EPA-402R-10003

FEDERAL GUIDANCE REPORT NO. 14

Radiation Protection Guidance for Diagnostic and In terventional X-Ray Procedures

Interagency Working Group on Medical Radiation U.S. Environmental Protection Agency Washington, D.C. 20460

2012

1I PREFACE 2

3 This document is Federal Guidance Report No. 14 (FG R 14), “Radiation Protection Guidance for 4 Diagnostic and Interventional X-ray Procedures.” I t replaces Federal Guidance Report No. 9 5 (FGR 9) (EPA 1976), “Radiation Protection Guidance for Diagnostic X-rays,” which was 6 released in October 1976. Federal Guidance reports were initiated under the Federal Radiation 7 Council (FRC), which was formed in 1959, through Ex ecutive Order 10831. A decade later its 8

functions were transferred to the Administrator of the newly formed Environmental Protection 9 Agency (EPA) as part of Reorganization Plan No. 3 o f 1970 (Dunn et al. 2012). Under these 10 authorities it is the responsibility of the Adminis trator to “advise the President with respect to 11 radiation matters, directly or indirectly affecting health, including guidance for all Federal 12 agencies in the formulation of radiation standards and in the establishment and execution of 13 programs of cooperation with States.” (EPA 2012) 14

15 FGR 9 provided constructive guidance on the use of diagnostic film radiography, for which there 16 was an incentive to deliver appropriate radiation d oses and avoid retakes resulting from under- or 17 over-exposing the film. This report, Federal Guida nce Report No. 14, focuses on the transition 18 to digital imaging, extends the scope (to include c omputed tomography (CT), interventional 19 fluoroscopy, bone densitometry, and veterinary prac tice), and updates sections on radiology and 20 dentistry that were covered in FGR 9. It also addr esses adequate imaging through justification of 21 the procedure and optimization, and features an exp anded section on occupational exposure. 22

23 FGR 9 was developed out of a growing concern in the 1970s among medical practitioners, 24 medical physicists, and other scientists that medic al uses of ionizing radiation represented a 25 significant and growing source of exposure for the U.S. population. Human exposures to 26 medical radiation were neither controlled by law no r covered by consensus guidance. In 1972, 27 the Federal Radiation Council released a report con cluding that “...medical diagnostic radiology 28

accounts for at least 90% of the total man-made rad iation dose to which the U.S. population is 29 exposed.” In response, the Environmental Protectio n Agency (EPA) and the Department of 30 Health, Education, and Welfare (predecessor of the Department of Health and Human Services 31 (DHHS)) developed and issued FGR 9, which was appro ved by President Carter (Carter 1978) 32 and published in the Federal Register on February 1, 1978. 33

34 According to EPA (Carter 1980), FGR 9 was the first Federal Guidance Report to provide a 35 framework for developing radiation protection progr ams for diagnostic uses of x-rays in 36 medicine. It introduced into Federal guidance the concepts of: 37

• Conducting medical x-ray studies only to obtain dia gnostic information, 38

• Limiting routine or elective screening examinations to those with demonstrated benefit 39 over risk, 40

• Considering possible fetal exposures during examina tions of pregnant or potentially 41 pregnant patients, 42

• Ensuring diagnostic equipment operators meet or exc eed the standards of credentialing 43 organizations, and 44

• Specifying that standard x-ray examinations should satisfy maximum numerical exposure 45

criteria. 46

47II

Much of FGR 9 has stood the test of time, but other parts have become obsolete. In particular, 48 the advent of digital x-ray image acquisition has e liminated film blackening as a built-in 49 deterrent to over-exposing patients. 50

51 Digital imaging methodologies have improved medical care by increasing the quality of 52 diagnostic images and significantly decreasing the need for exploratory surgeries. However, in 53 some cases, the use of this newer technology was ac companied by a significant increase in 54 patient radiation dose (Seibert et al. 1996). Some newly introduced technologies, e.g., CT, 55 yielded higher patient doses than the radiographic procedures they replaced. Finally, increased 56 utilization of imaging studies resulted in a greate r radiation dose to the population. 57

58 The U.S. Food and Drug Administration’s (FDA) perfo rmance standards for radiation emitting 59 products address radiography, fluoroscopy, and CT e quipment, and are codified at 21 CFR Part 60 1020 (FDA 2012e). The FDA revised these performanc e standards in 2005, in part to address 61

some of the radiation dose issues. 62

63

The National Council on Radiation Protection and Me asurements (NCRP) reports that medical 64 radiation exposure to the average member of the US population has increased rapidly and 65 continues to do so. Their previous estimate, based on 1970’s and early 1980’s data, was that 66 medical exposure accounted for 0.53 millisievert (m Sv) or 53 millirem (mrem) per year, which 67 was 15% of the total annual average (per capita) do se (NCRP 1989a). Based on 2006 data, this 68 estimate was increased to 3 mSv (300 mrem) per year or 48% of the total (NCRP 2009). 69

70

Concerns continue to be raised about the risks asso ciated with patients’ exposure to radiation 71 from medical imaging (Amis et al. 2007; FDA 2010b; FDA 2012e). Because ionizing radiation 72 can cause damage to DNA, exposure may increase a pe rson’s lifetime risk of developing cancer. 73 Although the risk to an individual from a single ex am may not itself be large, millions of exams 74 are performed each year, making radiation exposure from medical imaging an important public 75 health issue (Brenner 2007). Berrington de Gonzále z et al. estimate that approximately 29,000 76 future cancers could be due to CT scans performed i n the U.S. in 2007 (Berrington de González 77 et al. 2009). Smith-Bindman et al. estimate that 1 in 270 women and 1 in 600 men who undergo 78 CT coronary angiography at age 40 will develop canc er from that CT scan; the risks for 20-year79 olds are estimated to be roughly twice as large, an d those for 60-year-olds are estimated to be 80 roughly half as large (Smith-Bindman et al. 2009). Although experts may disagree on the extent 81 of the risk of cancer from medical imaging, there i s uniform agreement that care should be taken 82 to weigh the medical necessity of a given level of radiation exposure against the risks. 83

84 Given these changes in the available technologies, the reported increase in annual dose from 85 medical imaging, and concerns addressed above, EPA has decided to issue this new guidance to 86 the Federal medical community. Also, it is suitabl e for use by the broader medical community. 87 This guidance creates no binding legal obligation; rather, it offers recommendations for the safe 88 and effective use of x-ray imaging modalities. Fed eral agencies that adopt these 89 recommendations (e.g., into orders or standard oper ating procedures) should, at their discretion, 90 strengthen these statements where appropriate. EPA believes that the information contained in 91 this guidance will help users of diagnostic imaging equipment ensure that any given procedure is 92 justified for the patient being examined and that t he dose delivered to that patient is optimized. 93III

EPA also believes that the information contained in this guidance will provide for radiation 94 protection of medical workers. The goal of radiati on management is to keep patient and worker 95 radiation doses as low as reasonably achievable con sistent with the use of appropriate equipment 96 and the imaging requirements for specific patients and specific procedures. 97

98 FGR 14 establishes guidance for digital x-ray imagi ng that addresses protection aspects that were 99

not envisioned in FGR 9. These include: 100

• Reference levels and dose optimization 101

• Newer dose metrics 102

• Introduction of positron emission tomography/comput ed tomography (PET/CT) 103

• Computed tomography (CT), fluoroscopy (including in terventional fluoroscopy), bone 104 densitometry, and veterinary imaging as modalities additional to radiography and 105 dentistry 106

107 In carrying out its federal guidance responsibiliti es, EPA works closely with other federal 108 agencies through its participation on the Interagen cy Steering Committee on Radiation Standards 109 (ISCORS). Moreover, EPA recognizes, as it did in 1 976, that the expertise needed to make 110 sound recommendations for reducing unnecessary radi ation exposure due to the medical use of 111 x-rays in diagnostic and interventional procedures resides in several agencies. Therefore, this 112 report was prepared by the interagency Medical Work Group of the ISCORS Federal Guidance 113 Subcommittee that included physicians, medical phys icists, health physicists, and other scientists 114 and health professionals from the Department of Def ense, the Department of Veterans Affairs, 115 the Department of Health and Human Services, the De partment of Labor, and the EPA. 116

117 As in FGR 9, the recommendations contained in this report represent consensus judgment of the 118 Medical Work Group for the practice of diagnostic a nd interventional imaging by Federal 119 agencies. Since the body of knowledge on both the radiation exposure and efficacy of x-ray 120 examinations is rapidly changing, comments and sugg estions on the areas addressed by this 121 report will assist EPA to conduct periodic reviews and to make appropriate revisions. 122

123

124

125

126

127

128

129IV RECOMMENDATIONS FOR AGENCY ACTIONS 130

131

1. Patient safety requires that infrastructure exists for collecting, storing, and analyzing patient 132 dosimetry data. Federal facilities should plan for longitudinal tracking of patient radiation 133 doses. This planning should address the data acqui sition, networking, storage, analysis, and 134 security requirements of existing and planned futur e diagnostic devices. 135

2. All uses of radiation in diagnostic medical imaging should be justified and optimized. This 136 is the responsibility of all involved providers and technologists. Dose management begins 137 when a patient is considered for a procedure involv ing ionizing radiation, involves 138 equipment setup before the exam begins, and ends wh en any necessary radiation-related 139 follow-up is completed. 140

3. It is strongly recommended that the justification o f medical exposure for an individual 141 patient be carried out by the Referring Medical Pra ctitioner, in consultation with the 142 Radiological Medical Practitioner when appropriate. Each health care facility should 143 establish a formal mechanism whereby Referring Medi cal Practitioners have sources of 144 information available at the time of ordering regar ding appropriate diagnostic imaging 145 methods to answer the clinical question and to opti mize ionizing radiation dose to the 146 patient. 147

4. For each type of examination, Federal facilities an d agencies should promote the 148 development of national reference levels for use as quality assurance and quality 149 improvement tools. 150

5. For each type of examination there exists, within a vailable technology, an optimal 151 combination of imaging equipment and technique fact ors to produce adequate images at 152

doses below the reference level. Federal facilitie s should evaluate each imaging system’s 153 performance to optimize dose, and maintain this by establishing appropriate procedures and 154 conducting periodic monitoring. 155

6. Agencies should only adopt screening programs that have been submitted to rigorous 156 scientific evaluation of efficacy, as has been done for mammography, to ensure that the risk 157 posed to the population screened does not outweigh the benefits in detection of disease. 158

7. Agencies should use methods for estimating individu al occupational doses based on the 159 goal of assigning accurate doses rather than overly conservative estimates of doses. NCRP 160 Report No. 122 provides recommended methods for det ermining effective dose (E) and 161 effective dose equivalent. The various Federal reg ulatory agencies should establish 162 consistent methods and procedures for this purpose. 163V TABLE OF CONTENTS 164

165

PREFACE I 166

RECOMMENDATIONS FOR AGENCY ACTIONS IV 167

TABLES IX 168

INTERAGENCY WORKING GROUP ON MEDICAL RADIATION X 169

INTRODUCTION 1 170

RADIATION SAFETY STANDARDS AND GENERAL CONCERNS 4 171

GENERAL PRINCIPLES OF RADIATION PROTECTION 4 172

GENERAL STANDARDS FOR PROTECTION AGAINST RADIATION 6 173

Minors as Workers 6 174 Embryo or Fetus of Pregnant Workers 6 175

Members of the Public 7 176

GENERAL CONCEPTS FOR RADIATION PROTECTION 7 177

RADIATION SAFETY PROGRAM 8 178
Radiation Safety Officer 8 179
Qualified Physicist 9 180 Personnel and Area Monitoring 9 181
Patient Safety 10 182
Radiation Safety Procedures for Fluoroscopy 10 183
Special Patient Populations 11 184
Pregnant patients 11 185
Pediatric patients 12 186
Patients enrolled in a research protocol 12 187
Analysis of Risk from Radiation 13 188
Informed Consent for Research Involving Radiation 14 189
Occupational Radiation Safety Training 14 190
Notification and Reporting Requirements 14 191

STRUCTURAL SHIELDING AND DOOR INTERLOCK SWITCHES 15 192

REQUESTING AND PERFORMING STUDIES INVOLVING X-RAYS 15 193

REQUESTING STUDIES: REFERRING MEDICAL PRACTITIONERS (REQUESTING HEALTH 194
PROFESSIONALS) 15 195
Qualifications to Request X-ray Examinations 17 196

PERFORMING AND SUPERVISING STUDIES: RADIOLOGICAL ME DICAL PRACTITIONERS AND 197

TECHNOLOGISTS 17 198
Radiological Medical Practitioners 18 199VI

Radiologists 18 200
Medical Radiologic Technologists 19 201

SCREENING AND ADMINISTRATIVE PROGRAMS 19 202 Chest Radiography 20 203
Mammography 20 204

REFERRAL AND SELF-REFERRAL EXAMINATIONS 20 205
Patients Requesting Imaging on Themselves without a Referral from a Licensed Independent Practitioner 206
(Referring Medical Practitioner) 20 207
Physician Self-Referral 20 208

COMMUNICATION AMONG PRACTITIONERS 21 209

TECHNICAL QUALITY ASSURANCE IN MEDICAL IMAGING WITH X-RAYS 23 210

TECHNIQUE FACTORS 23 211

TESTING BY A QUALIFIED PHYSICIST 24 212

EQUIPMENT FAILURE 25 213

DEFICIENCY CORRECTION VERIFICATION 25 214

DOSIMETRY 25 215

REFERENCE LEVELS 26 216

GUIDANCE BY DIAGNOSTIC AND INTERVENTIONAL MODALITY 28 217

INTRODUCTION 28 218

RADIOGRAPHY 30 219
Equipment 30 220
Testing and Quality Assurance 31 221

Personnel 32 222
Radiological Medical Practitioner 32 223
Technologist 32 224
Other personnel 33 225

Procedures 33 226

FLUOROSCOPY 37 227 Equipment 37 228
Testing and Quality Assurance 40 229

Personnel 40 230

Procedures 42 231

Dose measurement 42 232
Recordkeeping 42 233 Patient management 43 234
Quality process 44 235
Staff safety 46 236

COMPUTED TOMOGRAPHY 47 237
Equipment 48 238
Testing and Quality Assurance 49 239

Personnel 49 240

Procedures 49 241VII

BONE DENSITOMETRY 52 242
Equipment 52 243
Testing and Quality Assurance 53 244

Personnel 55 245

Procedures 56 246

DENTAL 58 247
Equipment 58 248
Testing and Quality Assurance 60 249

Personnel 61 250

Procedures 62 251

VETERINARY 64 252
Equipment 64 253
Testing and Quality Assurance 65 254

Personnel 66 255

Procedures 66 256
Veterinary clinic setup 66 257
Personal protective equipment 67 258

Animal restraint 67 259
Use of x-ray equipment 67 260
Personal dosimetry 68 261
Special procedures for portable hand-held systems 68 262

MEDICAL IMAGING INFORMATICS 69 263

SUMMARY AND RECOMMENDATIONS FOR FACILITY ACTION 71 264

GENERAL 71 265

BONE DENSITOMETRY 71 266

CHILDREN AND PREGNANT WOMEN 72 267

DENTISTRY 72 268

FLUOROSCOPY 72 269

VETERINARY 73 270

INFORMATICS 73 271

INFORMED CONSENT 73 272

PRESCRIPTION 73 273

REFERENCE LEVELS 74 274

ACRONYMS AND ABBREVIATIONS 75 275

GLOSSARY 78 276

APPENDIX A – NIH INFORMED CONSENT TEMPLATES A-1 277

MINIMAL RISK A-2 278VIII

MINOR TO INTERMEDIATE RISK A-3 279

REFERENCES REF-1 280

281

282IX TABLES 283

284 Table 1. Testing Frequency of Imaging Equipment tha t Produces X-Rays ................................. 24 285 Table 2. Quality Assurance Measures for Film and Di gital Modalities .................................. ..... 34 286

287

288

289X INTERAGENCY WORKING GROUP ON MEDICAL RADIATION 290

291 292

293 Department of Health and Human Services 294 L. Samuel Keith, MS, CHP, CO-CHAIR 295 John L. McCrohan, MS (retired) 296 Donald L. Miller, MD, FSIR FACR 297 Petro Shandruk (retired) 298

299 Department of the Air Force 300 Cindy L. Elmore, Ph.D., DABR 301 LTC Scott Nemmers, BSC 302

303 Department of the Army 304 COL Mark W. Bower, CHP, Ph.D. 305 COL Erik H. Torring, DVM, MPH 306

307 Department of Labor, 308 Occupational Safety and Health Administration 309 Doreen G. Hill, MPH, Ph.D. 310

311 Department of the Navy 312 CAPT Stephen T. Sears, MC, CO-CHAIR 313 CAPT Michael A. Ferguson, MC 314 CDR Douglas W. Fletcher, MSC 315 CDR Chad A. Mitchell, MSC 316

317 Department of Veterans Affairs 318 Ronald C. Hamdy, MD, FRCP, FACP 319 Edwin M. Leidholdt, Jr., Ph.D. 320 Eleonore D. Paunovich, DDS, MS 321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340 341 Environmental Protection Agency 342 Michael A. Boyd, MSPH 343

344 Commonwealth of Pennsylvania 345

John P. Winston 346

347 Expert Consultants/Other Contributor s 348 Kimberly Applegate, MD, MS, FACR 349 Charles E. Chambers, MD, FACC FSCAI 350 Steven Don, MD 351 Marilyn Goske, MD 352 Fred A. Mettler, MD, MPH, FACR 353 Terrence J. O’Neil, MD, FACP 354 S. Jeff Shepard, MS 355 Dana M. Sullivan, RT(R)(M) , DVA 356

357

358

359

360 Acknowledgements 361

362 Environmental Protection Agency 363 Helen Burnett (retired) 364

Jessica Wieder 365

366 Department of Health and Human Services 367 J. Nadine Gracia, MD 368

Sandra Howard 369

3701 INTRODUCTION 371

372 There are a few commonalities that are integrated t hroughout this document. 373

374

1. This guidance was written without regard to specifi c models of equipment 375

2. It is intended to be a practical and appropriately prescriptive tool. 376

3. A balance was struck between being sufficiently spe cific and keeping the document generic 377 enough to remain current. 378

4. Dose reduction has been offset by increased utiliza tion (number and type of procedures) 379

5. Dose reduction technology should be incorporated in to the equipment. 380

6. Dose reduction technology only works when it is use d. 381

7. Operators need initial and periodic refresher train ing, easy to use tools (e.g., checklists), 382

and motivation. 383

8. Dose reduction strategies should be integrated into protocols, where possible. 384

9. Improvements in imaging and equipment will continue

. 385

386 The fundamental objective in performing an x-ray ex amination is to obtain the required 387 diagnostic information with only as much radiation dose as is required to achieve adequate image 388 quality. Achievement of this objective requires: 1 ) assuring equipment is functioning properly 389 and calibrated, 2) assuring equipment is operated o nly by competent personnel, 3) appropriately 390 preparing the patient, and 4) selecting appropriate equipment and using appropriate protocols. 391

392 Even more so than when the original FGR 9 (EPA 1976 ) was published in 1976, imaging in 2012 393 plays a critical role in medical care within the Un ited States. In the approximately thirty years 394 that have elapsed since the early 1980s, medical im aging has grown rapidly in utilization and 395 capability (NCRP 1989a; NCRP 2009). Computed tomog raphy (CT) provided a new cross 396 sectional imaging method, initially for evaluating the contents of the skull and then for other 397 body cavities and organs, for assessing tissues and organs that previously required surgery for 398 evaluation. This resulted in fewer exploratory sur gical procedures and permitted more accurate, 399 non-invasive diagnoses. The number of CT procedure s is growing at a rate greater than 10% per 400

year. 401

402 Smaller image detector elements increased the spati al resolution of CT imaging. Other 403 technological improvements have included improved m echanical function, multi-row detector 404 CT scanners, more capable computer technology, and improved x-ray tubes. As a result CT now 405 permits evaluation of physiologic characteristics a s well as anatomy, and permits pediatric exams 406 previously limited by motion artifact. Indications for imaging have increased as have use of 407 multi-sequence studies that allow organs to be eval uated during several phases of contrast 408

enhancement. 409

410 Improvements in fluoroscopy detector systems and im provements in techniques and equipment 411 (catheters, stents, embolic agents) facilitated an increase in the number and variety of image412 guided interventions. These procedures replaced ma ny open surgical procedures and now 413 provide new therapy options for many diseases. 414

415 With the vast information available through imaging and the increased availability of CT and 4162

fluoroscopy systems, there has been a marked increa se in the contribution of radiation dose from 417 x-ray based medical studies to the overall radiatio n dose to the US population. CT imaging 418

studies increased from 3 million in 1980 to 62 mill ion in 2006, at which time, scans were 419 increasing at the rate of 10% per year (ACR 2007d; NCRP 2009). During this period, the 420 estimated effective dose from all x-ray-related med ical procedures other than radiation therapy 421 increased from 0.39 to 2.23 millisievert per year ( mSv/y) (39 to 223 millirem per year (mrem/y)), 422 or from 11% to 36% of the total US population dose. By 2006, the annual x-ray effective dose in 423 the U.S. virtually equaled that from radon as well as the worldwide collective dose resulting 424 from the Chernobyl disaster (ACR 2007d; NCRP 2009). 425

426 Human epidemiological studies have demonstrated the potential of ionizing radiation to induce 427 cancer at an effective dose greater than 0.1 Sv. I t is prudent to consider that lower doses might 428 also carry a risk. National and international orga nizations have classified ionizing radiation 429 (including x-rays) as a known human carcinogen (NTP 2011). These groups include the 430 National Toxicology Program and the World Health Or ganization’s International Agency for 431 Research on Cancer (IARC 2012). 432

433 Technological advances have improved diagnostic cap abilities and image quality. Some of these 434 advances entail increases in patient dose. However , some have provided new and effective 435 methods for reduction of radiation exposure. Impro vements in film and film-screen technology 436 permitted reduction in the amount of radiation dose necessary to obtain standard images like the 437 chest radiograph. Improvement in image intensifier s and digital image receptors decreased the 438 amount of radiation necessary for fluoroscopic stud ies and the advent of pulsed fluoroscopy 439 permits even further reduction in the radiation req uired for a given imaging study. Simple 440 advances such as “last image hold” that cause the l ast image acquired to remain on the video 441 display screen after the fluoroscopy is stopped mar kedly reduce the dose of radiation involved in 442 these studies. Transition to improved systems also markedly reduced the radiation dose 443 necessary for mammography. In CT, improvements in detector composition and function, dose 444 modulation based on the patient’s size and body par t examined, advanced reconstruction 445 algorithms, and prospective acquisition gating duri ng the cardiac cycle have all provided 446 methods to significantly reduce the radiation dose from imaging studies. 447

448

Research has demonstrated that these dose-reduction techniques are not always employed or 449 used to best advantage in medical imaging, and medi cal education does not typically provide 450 focus on the effects of and protection from radiati on exposure (ICRP 2000b). Seemingly simple 451 and obvious items, like altering the energy and amo unt of radiation used in imaging children as 452 compared with adults, have not been adopted univers ally. Some units with pulsed fluoroscopy 453 capability have never been used in that mode. This document is intended to assist the reader in 454 appreciating the need for understanding doses from procedures and maximizing the benefit-risk 455 ratio in the use of medical imaging systems. 456

457 The primary goal of medical imaging is to answer a clinical question or guide an intervention. 458 When performing medical imaging with ionizing radia tion, using only as much radiation dose as 459 is required to achieve adequate image quality shoul d be the second goal. There are several ways 460 to reduce radiation dose that will be discussed spe cifically in the sections dedicated to each 461 imaging modality. 4623 463 Important ways to reduce radiation exposure to pati ents are to avoid duplicate studies and to 464 avoid any study that does not contribute effectivel y to the primary goal of answering the clinical 465 question. Sharing digital images among facilities reduces patient radiation doses by precluding 466 unnecessary duplicative imaging. The individual re questing the imaging examination should 467 have sufficient knowledge of the radiation doses as sociated with imaging examinations to be 468 able to request the most effective imaging study th at provides the necessary information at the 469 lowest radiation dose. When appropriate, examinati ons not involving ionizing radiation are 470 preferable. Organizations, such as the American Co llege of Radiology (ACR) and American 471 College of Cardiology (ACC), have published guidanc e that can help health professionals choose 472 the most appropriate examinations to answer their c linical questions. 473

474 As an example, in the evaluation of a patient with cough and fever, a standard two view chest x475 ray series may provide adequate information for the diagnosis and treatment of pneumonia at a 476

small fraction of the radiation dose that would be delivered by a chest CT. Similarly, a CT 477 angiogram may provide visualization of a large vasc ular distribution in a single imaging run with 478 a lower radiation dose than the multiple digital su btraction angiographic sequences that may be 479 required to adequately visualize the same area. 480

481 Once a specific imaging study is selected, technica l aspects of the image acquisition become the 482

most critical influence on radiation dose delivered to the patient and quality of the resulting 483 images. Although reduction of radiation exposure o verall should be a goal, reduction of dose to 484

a level that results in an increased number of unsa tisfactory examinations requiring repeat 485 imaging will actually increase patient dose overall and should be avoided as much as excessive 486

dose should be. In the use of film-screen technolo gy, over and under exposure were evident on 487 the resulting image, but with digital based imaging , these conditions are not as apparent. One 488 reason is that image quality may continue improving with increasing dose, even beyond what is 489 needed or adequate. As a result, good clinical pra ctices include effective quality control 490 programs, optimized imaging protocols providing onl y the necessary sequences, adjustment of 491 technical factors and dose of radiation for patient size and age, and employment of the best 492 available dose reduction technologies existing in t he equipment in use. 493

494

This document is intended to assist the reader in v alidating their efforts and maximizing the 495 benefit:risk ratio in requesting and performing med ical diagnostic and interventional procedures 496 involving x-rays. The document is divided into sec tions based on imaging modality. 497

498

499

5004 RADIATION SAFETY STANDARDS AND GENERAL CONCERNS 501

502

GENERAL PRINCIPLES OF RADIATION PROTECTION 503

504 The International Commission on Radiological Protec tion (ICRP) has formulated a set of three 505 fundamental principles for radiation protection (IC RP 2007a; ICRP 2007c). These principles are 506 justification

, optimization of protection , and application of dose limits . The first two principles 507 apply to a source of exposure, and thus are intende d to support protection for all individuals who 508 may be exposed to that source. The third principle applies to occupational and public exposure, 509 but explicitly excludes medical exposure of patient s. 510

511 The principle of justification states that, in general, “any decision that alters the radiation 512 exposure situation should do more good than harm. This means that by introducing a new 513 radiation source, by reducing existing exposure, or by reducing the risk of potential exposure, 514

one should achieve sufficient individual or societa l benefit to offset the detriment it causes” 515 (ICRP 2007a; ICRP 2007c). With regard to medical e xposures specifically, “the principal aim of 516 medical exposures is to do more good than harm to t he patient, subsidiary account being taken of 517 the radiation detriment from the exposure of the ra diological staff and of other individuals” 518 (ICRP 2007a). 519

520 The ICRP (ICRP 2007a) addresses justification in me dicine as follows: 521

522 “The principle of justification applies at three le vels in the use of radiation in medicine. 523 At the first level, the use of radiation in medicin e is accepted as doing more good than 524 harm to the patient. This level of justification c an now be taken for granted. 525

526 “At the second level, a specified procedure with a specified objective is defined and 527 justified (e.g., chest radiographs for patients sho wing relevant symptoms, or a group of 528

individuals at risk to a condition that can be dete cted and treated). The aim of the second 529 level of justification is to judge whether the radi ological procedure will usually improve 530 the diagnosis or treatment or will provide necessar y information about the exposed 531

individuals. 532

533 “At the third level, the application of the procedu re to an individual patient should be 534 justified (i.e., the particular application should be judged to do more good than harm to 535 the individual patient). Hence all individual medi cal exposures should be justified in 536 advance, taking into account the specific objective s of the exposure and the 537

characteristics of the individual involved.” 538

539 The principle of optimization of protection states that “the likelihood of incurring exposures , the 540 number of people exposed, and the magnitude of thei r individual doses should all be kept as low 541 as reasonably achievable, taking into account econo mic and societal factors. This means that the 542 level of protection should be the best under the pr evailing circumstances, maximizing the margin 543 of benefit over harm” (ICRP 2007a; ICRP 2007c). 544

5455

The principle of application of dose limits states that “the total dose to any individual from 546 regulated sources in planned exposure situations ot her than medical exposure of patients should 547 not exceed the appropriate limits recommended by th e Commission” (ICRP 2007a; ICRP 548 2007c). It is important to note this definition ex plicitly excludes medical exposure of patients. 549 Dose limits do not apply to medical exposure, which is defined by the ICRP as “the exposure of 550 persons as part of their diagnosis or treatment (orexposure of a patient’s embryo/fetus or breast551 feeding infant) and their comforters and carers (ot her than occupational)” (ICRP 2007c). As the 552 ICRP has stated, “Provided that the medical exposur es of patients have been properly justified 553

and that the associated doses are commensurate with the medical purpose, it is not appropriate to 554 apply dose limits or dose constraints to the medica l exposure of patients, because such limits or 555 constraints would often do more harm than good” (IC RP 2007c). This recommendation against 556 establishing absolute dose limits should not discou rage a facility from implementing threshold 557 guidelines for diagnostic procedures that trigger a review of practice at the facility, or from 558 establishing dose notification and alert values for CT (NOTE:cite NEMA standard XR25-2010 to 559 be provided by Ed 2012-08-17). 560

561 When an interventional procedure is indicated, the medical condition being treated and the non562 radiation risks of the procedure typically present a substantially greater risk of morbidity and 563 mortality than do the radiation risks (Miller 2008)

. 564

565 While dose limits do not apply to medical exposures , each physician must always strive to 566 minimize patient irradiation to the dose that is ne cessary to perform the procedure. Therefore, 567 radiation doses to patients should always be optimi zed. 568

569 The concept of patient radiation dose optimization is used throughout this document. Dose 570 optimization means delivering a radiation dose to t he organs and tissues of clinical interest no 571 greater than that required for adequate imaging and minimizing dose to other structures (e.g., the 572 skin (FDA 1994)). Patient radiation dose is consid ered to be optimized when imaging is 573 performed with the least amount of radiation requir ed to provide adequate image quality and, for 574 fluoroscopy, adequate imaging guidance (NIH NCI SIR 2005). The goal of every imaging 575 procedure is to provide images adequate for the cli nical purpose. What constitutes adequate 576 image quality depends on the modality being used an d the clinical question being asked. 577 Imaging requirements depend on the specific patient and the specific procedure. Reducing 578 patient radiation dose to the point where images ar e inadequate is counterproductive; it results in 579 radiation dose to the patient without answering the clinical question, ultimately resulting in the 580 need for additional radiation dose. Improving imag e quality beyond what is clinically needed 581 subjects the patient to additional radiation dose w ithout additional clinical benefit. The goal of 582 patient radiation management is to keep patient rad iation dose as low as reasonably achievable 583 consistent with the use of appropriate equipment an d the imaging requirements for a specific 584 patient and a specific procedure. 585

586 Ideally, dose would be accurately measured or estim ated in relevant tissues and organs in real 587 time. As of 2012, this is not possible. Currently , radiation dose is measured differently for CT, 588 fluoroscopically-guided procedures, and radiography due to the endpoint health effect of interest 589 (cancer or acute tissue damage), the way radiation is detected, and the way dose is calculated. 590

The dose metrics and units of measurement used for patient radiation dose measurement are 5916

necessarily dependent on the equipment and modality being used. Different dose metrics are 592 managed in different ways. For example, during flu oroscopically-guided procedures, it is 593 desirable to optimize kerma area product and refere nce air kerma (indicators of patient dose) 594 while also minimizing peak skin dose. The most app ropriate dose metrics available should be 595

used. 596

597

598

GENERAL STANDARDS FOR PROTECTION AGAINST RADIATION 599

600 Federal facilities must have safety programs in pla ce to protect workers, as required by Public 601 Law 91-596, Section 19 entitled Federal Agency Safe ty Programs and Responsibilities (Congress 602 2004) and Executive Order 12196 entitled Occupation al Safety and Health Programs for Federal 603 Employees (Carter 1980). For medical imaging the s tandards for protection against ionizing 604 radiation are promulgated by the Nuclear Regulatory Commission (NRC) for radioactive 605 materials in 10CFR20 (USNRC 2012c), and the US Occu pational Safety and Health 606 Administration (OSHA) for x-rays in 29CFR1910 (OSHA 2012). If both radioactive materials 607 and x-rays are utilized, then NRC regulations gener ally take precedence. Portions of the NRC 608 and OSHA regulations, when considered together, est ablish dose limits for staff and members of 609 the public; requirements for the wearing of dosimet ers; requirements for the posting of warning 610 signs; periodic employee training and hazard commun ication; comprehensive record keeping for 611 exposure monitoring results, periodic facility medi cal physicist assessments, and preventive 612 interventions; and timely reporting of results of e xposure monitoring and exposure incidents to 613 individual employees, including exposures to staff or members of the public that exceed 614 regulatory limits. It is important to note that th ese dose limits are for occupational, incidental, 615 and public exposure and do not specifically limit t he exposure that a patient may receive as a 616 result of medical evaluation or treatment in the pr ocess of their personal health care. As of 2012, 617 and consistent with recommendations from ICRP, ther e is no regulatory limit on the amount of 618 radiation a patient may receive. 619

620

Minors as W orkers 621

622

Readers of this document should be aware that the F ederal Regulations cited above also provide 623 direction concerning occupational radiation exposur e to individuals below the age of 18. Dose 624 limits for these individuals are generally 10% of t he occupational dose limits for adults. 625

626 Embryo or Fetus of Pregnant W orkers 627

628 As of 2012, the occupationally received dose equiva lent to the embryo or fetus of a radiation 629 worker who has voluntarily declared her pregnancy i n writing shall not exceed 5 mSv (0.5 rem) 630 during the remainder of the pregnancy, or an additi onal 0.5 mSv (0.05 rem) if the gestation limit 631 has been or is within 0.5 mSv (0.05 rem) of being e xceeded when the declaration is made 632 (USNRC 2012b). This limit does not pertain to the exposure of an embryo or fetus resulting 633 from a medical procedure to the pregnant worker. W hen a radiation worker informally advises 634 the facility that she is, might be, or is attemptin g to become pregnant, her past and current 635 exposure values should be evaluated and risks assoc iated with radiation exposure to the fetus 636 should be discussed. If she formally declares her pregnancy (i.e., becomes a “declared pregnant 6377

woman” per 10CFR20.1003 (USNRC 2012a)), she should be issued a dosimeter to be worn on 638 the lower abdomen, under the apron, at the level of the fetus, and exchanged monthly, unless 639 such a dosimeter is already being worn. The facili ty should avoid substantial variation above a 640 uniform monthly exposure rate of 0.5 mSv/month. 641

642

Members of the Public 643

644 The total effective dose equivalent to an individua l member of the public should not exceed 645 1 mSv (100 mrem) in a year from occupancy in uncont rolled areas in or near medical radiation 646 facilities (NCRP 2004a). In health care facilities , all non-radiation workers (e.g., janitorial staff

, 647 secretaries) should be afforded protection consiste nt with that afforded members of the public. 648 This is relevant to the design of radiation shieldi ng and occupancy limits. 649

650

651

GENERAL CONCEPTS FOR RADIATION PROTECTION 652

653 There are several principles by which workers can m inimize their exposure to x-rays. Most of 654 them are based on certain fundamental concepts conc erning x-rays: (1) limiting the time of 655 exposure reduces the dose, (2) except at short dist ances, radiation intensity is inversely 656 proportional to the square of the distance from the radiation source (Inverse Square Law), and (3) 657 x-rays travel in straight lines from their source a nd can be attenuated by shielding. Those who 658 are exposed to radiation should judiciously use tim e, distance, and shielding to limit their 659

radiation dose. 660

661 Humans should be exposed to the unattenuated primar y radiation beam(s) of x-ray imaging 662 equipment in federal medical facilities only for me dical purposes. For this definition, “medical 663 purposes” include research involving the exposure o f human subjects conducted in accordance 664 with the Federal Policy for the Protection of Human Subjects (OSTP et al. 1991). In particular, 665 humans may not be exposed to these unattenuated bea ms solely for training, to test equipment, or 666 to obtain images for accreditation. The only excep tion to this requirement is that precision 667 assessments may be made in dual energy x-ray bone d ensitometry in accordance with the 668 guidelines of the International Society for Clinica l Densitometry (ISCD 2007a; ISCD 2007b). 669

670 Optimization of protection is at the heart of a suc cessful radiation control program. It involves 671 evaluating and, where practical to do so, incorpora ting measures to reduce collective dose and 672 minimize the number of people exposed. In accordan ce with the ICRP’s principle of 673 optimization of protection, each facility should us e, to the extent practicable, procedures and 674 engineered controls to achieve occupational doses a nd doses to members of the public that are as 675 low as reasonably achievable (ALARA), with economic and social factors being taken into 676 account. The ALARA approach is applied after it ha s been determined that a proposed activity 677 will not exceed any mandatory dose limit. 678

679 The ALARA approach requires that only people whose presence is necessary are permitted in the 680 room while images are acquired. For radiation prot ection purposes, it is strongly recommended 681 that these people be shielded from radiation by mea ns such as protective aprons and/or portable 682 shields and maintain as much distance as possible f rom the point where the x-ray beam intersects 6838

the patient. To limit worker dose, it is strongly encouraged that the operator be behind a shielded 684 barrier when observing the patient during image acq uisition. 685

686

687

RADIATION SAFETY PROGRAM 688

689 A radiation safety program is the mechanism for an institution to ensure that: 690

• the use of ionizing radiation within its purview is performed in accordance with existing 691 laws and regulations, 692

• individual health professionals and technologists a re equipped with knowledge of the 693 options available to them as they make benefit:risk determinations and prescribe the 694 appropriate examination for each individual patient , and 695

• x-ray equipment users and the surrounding public re ceive adequate protection from this 696

radiation. 697 The primary objective is to obtain necessary diagno stic information or interventional results with 698 minimum irradiation of the patient. This also help s keep exposure to staff and members of the 699 public at a minimum. The key personnel and activit ies involved in managing a radiation safety 700

program are: 701

702 Radiation Safety Officer 703

704 The Radiation Safety Officer (RSO) is responsible f or radiation safety. The RSO may be the 705 same person designated for radiation safety for NRC purposes under Title 10, Code of Federal 706 Regulations, Part 35 (USNRC 2012d). An RSO should be designated for each facility that uses 707 ionizing radiation for medical imaging, and should be appointed in writing by the facility 708 director or agency. The RSO shall be permitted to directly communicate with facility executive 709 management. The RSO, whenever possible, should be a qualified expert as defined in this 710 document. The RSO should be a person having knowle dge and training in ionizing radiation 711 measurement and evaluation of safety techniques and the ability to advise regarding radiation 712 protection needs (for example, a person certified i n diagnostic medical physics by the American 713 Board of Radiology, or in health physics by the Ame rican Board of Health Physics, or those 714 having equivalent qualifications). The RSO has the following specific responsibilities: 715

716

1. Establish and implement radiation safety procedures and review them periodically to assure 717 their conformity with regulations and good radiatio n safety and medical physics practices. 718

2. Instruct personnel in regulatory requirements and p roper radiation protection practices 719 before they begin working with radiation and period ically thereafter to maintain and update 720 that knowledge. 721

3. Conduct or supervise radiation surveys where indica ted and keep records of such surveys 722 and tests, including summaries of corrective measur es recommended and/or instituted. 723

4. Assure that area monitoring and personnel monitorin g devices are used as required and 724 records are kept of the results of such monitoring. This function requires reviewing the 725 monitoring reports promptly to ensure that public a nd personnel doses do not exceed 726 regulatory limits and are ALARA, making dosimetry r ecords available to each worker at 727 any time, and periodically informing workers of the ir dose record. These records will be 7289

kept in a suitable organized file (readily retrieva ble but not necessarily on site) for the life 729 of the facility or as legally required. 730

5. Assure that any warning signals on imaging equipmen t and suites are regularly checked for 731 proper function and that required signs are properl y posted. 732

6. Monitor compliance with the requirements of regulat ions and the requirements specified in 733 the facility’s standard operating procedures. 734

7. In conjunction with a qualified physicist, promptly investigate each known or suspected 735 case of excessive or abnormal exposure, determine t he causes, take steps to prevent its 736 recurrence, monitor such corrective actions, and ma ke appropriate reports. 737

8. Ensure that required notifications and reports in t he case of personnel overexposures and 738 radiation medical events are submitted as required by regulations. 739

9. Promptly notify facility executive management of si gnificant safety hazards, significant 740 violations of regulations, exposures of staff or me mbers of the public that exceed regulatory 741 requirements, and radiation medical events. 742

10. Review or have a qualified expert review, prior to construction or modification, plans for 743 rooms in which x-ray producing equipment is to be i nstalled, including room layout, 744 shielding (AAPM 2006c; NCRP 2004a), and viewing and communications systems, and 745 verify that the shielding is installed according to plan and functions as designed before 746 clinical use of the equipment. 747

748 Qualified Physicist 749

750 The services of a qualified physicist are essential for the optimal use of medical imaging. The 751 following services should be performed by or under the supervision of a qualified physicist: 752

753

1. Participate in evaluation and selection of equipmen t 754

2. Conduct acceptance testing of new equipment 755

3. Monitor imaging systems at least annually 756

4. Evaluate, in conjunction with the RSO, unexpected r adiation events 757

5. Oversee the technical QA program 758

6. Investigate the root causes of image quality issues and identify appropriate solutions. 759

7. Design or review and approve x-ray room radiation s hielding 760

8. Perform verification surveys of x-ray room shieldin g 761

9. Periodically review existing imaging protocols 762

10. Assist with development and evaluation of new and r evised imaging protocols 763

11. Perform patient-specific radiation dose calculation s (e.g., fetal dose calculations) 764

12. Provide training on quality control and radiation s afety 765

13. Ensure that instruments used to monitor x-ray imagi ng systems are appropriate for the task, 766 appropriately calibrated for the task (e.g., energy and dose rate measurements), and 767

maintained 768

14. Evaluate the radiation-related aspects of research protocols 769

770 Personnel and Area Monitoring 771

772 Each worker who is expected to receive more than 10 % of the applicable dose limit should be 773 required to wear one or more dosimeters. There sha ll be a procedure for regular issuance and 77410

replacement of dosimeters for exposure evaluation, and records of the doses received shall be 775 retained as required by NRC in 10CFR20 (USNRC 2012c ) and OSHA in 29CFR1910.1096 776 (OSHA 2012). When a protective apron is worn, one dosimeter should be worn at the collar 777 outside the apron. A second dosimeter may be worn on the abdomen under the apron. The two 778 dosimeter method provides a more accurate method of assessing effective dose (NCRP 1995). 779 When multiple dosimeters are issued to an employee, each dosimeter should be labeled to 780 indicate the location on the body where it is to be worn. Facilities should ensure that workers 781 wear dosimeters as required, and in the designated locations; failure to do so can result in 782

incorrect dose assessments. Periodic assessments a nd feedback to employees regarding their 783 exposures are particularly important. If there is a question, the facility can also post dosimeters 784 in public areas adjacent to rooms where x-rays are produced in order to quantify the amount of 785 radiation a person in those areas might receive. F acilities/agencies should use methods for 786 estimating individual doses based on the goal of as signing accurate doses. Federal regulatory 787 agencies should adopt methods and procedures consis tent with NCRP Report No. 122, which 788 provides recommended methods for determining effect ive dose (E) (NCRP 1995). 789

790

Patient Safety 791

792 As with all medical procedures, there are critical elements of patient safety that must be 793 observed. The first critical element is ensuring t hat the correct patient undergoes the specified 794 diagnostic test or interventional procedure, and th at the examination is performed on the 795 appropriate body part. To that end, each facility should have in place a specified method for 796 verification of patient identity prior to events su ch as administration of medication or surgical 797 procedures. These precautions should also be exten ded to diagnostic and interventional imaging. 798 If the medical procedure involves intervention or a specific side of the patient’s anatomy, the 799 specific body part should be confirmed prior to the procedure. The precautions should be 800

commensurate with the risk from the examination or procedure, with greater precautions being 801 taken for procedures of greater risk. 802

803 Radiation Safety Procedures for Fluoroscopy 804

805 It is strongly recommended that, other than for the patient being examined, only staff and 806 ancillary personnel required for the procedure, or those in training, be in the room during the 807 fluoroscopic examination (AAPM 1998; ACR 2008c). N o body part of any staff or ancillary 808 personnel involved in a fluoroscopic examination sh ould be in the primary beam. However, if 809 primary beam exposure is unavoidable, it should be minimized. It is essential that all personnel 810 in the room during fluoroscopic procedures be prote cted from scatter radiation by either whole811 body shields or protective aprons. For procedures performed using microampere fluoroscopy 812 systems, a qualified physicist should determine if aprons are required. 813

814 Aprons should provide the desired protection at an acceptable weight, because the apron weight 815 itself can pose a substantial ergonomic risk to its wearer. Apron weight can be reduced by using 816 thinner lead or by replacing lead, completely or pa rtially, with a combination of one or more 817

other materials that have the same or better attenu ation for the scattered radiation from 818 fluoroscopic beams. Though 0.5 mm lead-equivalent aprons are considered the standard as of 81911

2012, an apron with thinner lead equivalence may pr ovide adequate protection. Based on the 820 calculation of effective dose (E) from dual monitor s, a 0.3 mm lead-equivalent apron will result 821 in a value of E that is only moderately higher (7 t o 16 %) than a 0.5 mm lead-equivalent apron 822 (NCRP 1995). The two-dosimeter method described ab ove under PERSONNEL AND AREA 823 MONITORING may be preferable for monitoring person nel in the room during high dose 824 interventional procedures. Monthly dose monitoring can also be implemented to ensure that staff 825 members who use garments with < 0.5 mm lead equival ent thickness continue to maintain an 826 occupational dose below the required dose limits. W ith these precautions in place, it is quite 827 possible to provide adequate protection with a 0.35 mm or less lead equivalent thickness. 828

829 Thyroid and eyes should be protected if the potenti al exposure to the worker will exceed 25% of 830 the annual regulatory dose limits for those organs. It is strongly recommended that lead 831 personnel protective equipment (e.g., aprons, glove s, thyroid collars) be evaluated at least 832 annually for lead protection integrity using visual and manual inspection (Miller et al. 2010b; 833 NCRP 2010). If a defect in the attenuating materia l is suspected, radiographic or fluoroscopic 834 inspection may be performed as an alternative to im mediately removing the item from service. 835 Protective aprons, gloves and thyroid shields shoul d be hung or laid flat and never folded, and 836

manufacturer’s instructions should be followed. Co nsideration should be given to minimizing 837 the radiation exposure of inspectors by minimizing unnecessary fluoroscopy. 838

839 Special Patient Populations 840

841 Specific special populations addressed here include : 842

843

1. Pregnant patients 844

2. Pediatric patients 845

3. Patients enrolled in a research protocol 846

847 Occupational radiation exposure to minors and to th e fetus of a pregnant worker is discussed in 848 the section General Standards for Protection Agains t Radiation. 849

850 Pregnant patients 851

852 Because of the special risk that radiation exposure poses to the embryo or fetus, each facility 853 should establish and implement procedures to determ ine, before conducting an examination or 854 procedure, whether a female patient of childbearing age may be pregnant. 855

856 Signs should be posted in suitable locations, such as patient reception areas and procedure 857 rooms, asking female patients to notify staff if th ey might be pregnant. Consideration should be 858 given to alternate tests or procedures, such as ult rasound, that would not expose the embryo or 859 fetus to ionizing radiation, or to modifying the ex amination or procedure to reduce the radiation 860 dose to the embryo or fetus. 861

862

Evaluation of the benefit:risk ratio in relation to the radiation dose from medical imaging in a 863 pregnant woman is very complex. In instances where a study using ionizing radiation is deemed 864 necessary, every effort should be made to avoid exp osing the fetus to the direct radiation beam. 86512

If a patient is pregnant, a radiologist, radiation oncologist, or other physician knowledgeable in 866 the risk from the radiation exposure should work wi th the patient in making the decision whether 867 to perform the examination or procedure. There sho uld be a discussion of the benefits and risks 868 with a pregnant patient prior to the imaging unless an emergent need for the imaging or her 869 condition precludes this. If a previously unrecogn ized pregnancy is identified after a procedure, 870 the referring physician should be notified and the patient counseled as appropriate. 871

872 The precautions should be commensurate with the ris k from the examination or procedure to be 873 performed, with greater precautions being taken for procedures imparting larger radiation doses 874 to the abdomen or pelvic region of the patient. Th e physician might consider delaying the 875 procedure until after pregnancy so as to avoid expo sing the embryo or fetus. For procedures that 876 may impart a dose to this region, and especially fo r those exceeding 0.05 Gy (5 rad), the 877 anticipated dose and associated risks should be inc luded as part of informed consent and a serum 878 pregnancy test should be obtained, unless a physici an determines that the delay caused by 879 performing the test would harm the patient. A conf irmatory pregnancy test would not be 880 necessary if pregnancy can be excluded by documente d surgical or medical history. Procedures 881 that may impart a dose to the embryo or fetus excee ding 0.05 Gy (5 rad) are prolonged 882 fluoroscopic procedures to the abdomen or pelvis an d CT imaging involving two or more scans 883 of the abdomen or pelvis. 884

885

The dose to a fetus should be estimated. If the do se to the embryo or fetus could exceed 0.05 Gy 886 (5 rad), a formal dose assessment should be perform ed by a qualified physicist and provided with 887 consultation to the referring physician so that the patient can be advised accordingly. Doses at or 888 above 0.1 Gy (10 rad) warrant discussions between t he patient and her physician of potentially 889 adverse fetal effects, and the fetal dose assessmen t should be included in the medical record. 890

891 Pediatric patients 892

893

Children are more sensitive to radiation and also h ave greater expected remaining life spans than 894 adults. As such, children represent a population a t greater risk for subsequent development of 895

radiation induced cancer than adults. This differe nce in the benefit:risk ratio should be 896 considered in the prescription of medical imaging r equiring ionizing radiation. Alternative 897 imaging modalities that do not use ionizing radiati on, such as ultrasound or MRI, should be 898 considered for imaging children. 899

900 Protocols for all ionizing radiation imaging should be “child-sized” or optimized so that the dose 901 is appropriate for the size of the infant or child (FDA 2001; Strauss et al. 2010). For 902 radiography, fluoroscopy, and CT, this key principl e holds true. For example, unlike abdominal 903 CT studies performed in adults, pediatric CT studie s usually do not require multiple passes 904 through the child’s body. This reduces the radiati on dose to the child without compromising 905 diagnosis. 906

907 Patients enrolled in a research protocol 908

909 All research involving human subjects that is condu cted, supported, or otherwise subject to 910 regulation by any Federal department or agency must conform to the most current version of the 91113

Federal Policy for the Protection of Human Subjects (FPPHS) (OSTP et al. 1991). This policy 912 requires approval of research protocols by a proper ly constituted institutional review board (IRB) 913 and obtaining informed consent from the patient. 914

915 Many protocols use radiation that is medically indicated ( also referred to as “standard-of-care”)

. 916 Medically-indicated radiation is used to diagnose o r guide treatment as a non-research medical 917 procedure for clinical management of the research s ubject. The radiation dose from a medically918 indicated procedure done as part of a research stud y should not require additional justification, 919 review, and approval by an IRB. When the radiation exposure is described as indicated for 920

research (the radiation use does not meet the criteria of “m edically indicated”) it must be 921 reviewed and approved. IRBs have responsibility fo r oversight of research involving human 922 subjects, but usually seek the advice of the instit ution’s Radiation Safety Committee regarding 923 the radiation risk from any non-medically indicated radiation use that is a component of the 924

research

. 925

926 Analysis of Risk from Radiation 927

928 An analysis of risk to the human research subjects, including that from radiation exposure, must 929 be performed prior to preparation of the informatio n to be provided to the subjects to seek 930 informed consent and prior to review of the researc h study by the IRB. The risks of both 931

deterministic and stochastic effects from the radia tion exposure should be considered. For 932 consideration of the risk of deterministic effects, the maximal doses to individual organs and 933 tissues should be estimated, although dose rate and dose fractionation may also be considered. 934

935 The risk from stochastic effects, particularly canc er, should also be considered. Ideally, this risk 936 should be calculated from estimating doses to indiv idual organs and tissues and using organ and 937 tissue specific risk coefficients that account for the age and gender of the subject. The 938

International Commission on Radiation Units and Mea surements (ICRU) provides useful 939 information for determining patient dose (ICRU 2005 , or most current version). However, for 940 many imaging procedures, this approach would consum e considerable resources and requiring it 941 would discourage many research studies from being p erformed. 942

943 The ICRP developed the quantity effective dose (E) for radiation protection purposes to assess 944

the risk of detriment to workers from stochastic ef fects caused by occupational exposure to 945 ionizing radiation (Harrison and Streffer 2007; ICR P 1991a). This quantity was intended to be 946 applied to a population of working-age adults of bo th genders. Although effective dose was not 947 intended to be used for assessing risk from medical exposures, it is commonly used to convey the 948 potential risk from radiation exposure for subjects participating in investigational protocols 949 (Martin 2007). For many imaging procedures, the ef fective dose can be estimated easily. 950 Furthermore, effective dose provides a single quantity from participating in a research study tha t 951 can be compared to other sources of radiation expos ure (e.g., medical procedures and natural 952 background radiation). From the research subject’s perspective, this comparison is simple and 953 expresses the risk in a meaningful way. The effect ive dose may be used for estimating risk from 954 stochastic effects to human research subjects, but should not be used without considering its 955 appropriateness in light of the characteristics of the study population, including their ages and 956 genders, the body parts being irradiated, and their expected life-spans. ICRP Publication 62 95714

(ICRP 1991b) provides guidance on the use of effect ive dose in estimating risk to human 958 subjects. 959

960

Informed Consent for Research Involving Radiation 961

962 To enroll in any research study using human subject s, participants must be knowledgeable about 963 the risks, benefits, privacy considerations and oth er matters. They must participate voluntarily 964 and must provide written informed consent using an IRB-approved consent form. Requirements 965 for human research in x-ray imaging facilities are addressed in the Federal Register (OSTP et al. 966 1991) and are specified in the current Code of Fede ral Regulations sections that apply to 967 individual facility operations (e.g., 32CFR219 for DoD, 45CFR46 for DHHS, 40CFR26 for 968 EPA, and 38CFR16 for VA). Appendix A contains samp le informed consent templates for the 969 research use of radiation, adapted from those used by NIH in 2012 (NIH 2008a; NIH 2008b; 970 NIH 2010). 971

972 These consent documents have been developed for use when patients are irradiated for research 973 purposes as opposed to being irradiated for clinica l care. These documents explain risk based on 974

effective dose. The maximum level of radiation ris k should be expected to be minimal, minor to 975 intermediate, or moderate when the respective socie tal benefit is minor, intermediate to 976 moderate, or substantial (ICRP 1991b). The specifi c values of numerical dose for each of these 977 ranges may vary according to the specific IRB and t he specific research population. The sample 978 consent templates in Appendix A may be considered a s a starting point for IRB consideration for 979 the general adult population. These consent templa tes should be modified as appropriate to meet 980 the particular requirements or needs of a given stu dy. 981

982 Occupational Radiation Safety Training 983

984 Each facility should train staff who operate x-ray producing equipment or who are routinely 985 exposed to radiation by the equipment. Training sh ould be provided initially prior to utilization 986 of the equipment and at least annually thereafter. The training should be commensurate with risk 987 to the staff and to the patient. It should include the risks from exposure to ionizing radiation, 988 regulatory requirements, recommendations of this gu idance document, facility requirements, 989 proper operation of the equipment, methods for main taining doses to staff within regulatory 990 limits and as low as reasonably achievable, and gui dance for protecting the patient and embryo 991

or fetus. 992

993 Notification and Reporting Requirements 994

995 If radiation exposures to staff or members of the p ublic exceed regulatory limits, the facility shall 996 make notifications and reports as required by the N RC or OSHA (OSHA 2012; USNRC 2012c). 997

998

99915 STRUCTURAL SHIELDING AND DOOR INTERLOCK SWITCHES 1000

1001 To prevent inadvertent patient injury or the need t o repeat exposures of patients, it is strongly 1002

recommended that interlock switches that terminate x-ray production not be placed on doors to 1003 any diagnostic or interventional x-ray room (NCRP 2 004a). 1004

1005 For the structural shielding of rooms containing x- ray imaging or x-ray-producing devices, the 1006 shielding design goal should be 5 mGy in a year to any person in controlled areas. For 1007 uncontrolled areas, the shielding design goal shoul d be a maximum of 1 mGy to any person in a 1008 year (0.02 mGy per week) (NCRP 2004a). Shielding d esign for and acceptance testing surveys 1009 of imaging rooms should be performed or reviewed by a qualified physicist using appropriate 1010 methodology such as is provided in NCRP reports. W henever room modifications are performed 1011 or the assumed shielding parameters change (e.g., n ew equipment, increased workload, or altered 1012 use of adjacent spaces), the suitability of the des ign should be reviewed by a qualified physicist. 1013 The shielding design calculations, as-built shieldi ng plans, and the report on the acceptance 1014 testing of the structural shielding should be kept for the duration of use of the room for x-ray 1015 imaging. The American Association of Physicists in Medicine guidance should be used as 1016 appropriate, for modalities not covered in NCRP rep orts. At the time of this writing, this 1017 includes guidance for PET/CT shielding (AAPM 2006c)

. 1018

1019 Mobile radiographic equipment is frequently used fo r bedside examinations. Effective radiation 1020 protection in these circumstances is normally provi ded through exposure time and distance 1021 (NCRP 1989b; NCRP 2000; NCRP 2004a). When mobile r adiographic or fluoroscopic 1022 equipment is used in a fixed location, or frequentl y in the same location, it is strongly 1023 recommended that a qualified expert evaluate the ne ed for structural shielding (NCRP 2004a). 1024 When radiographic or fluoroscopic equipment is used in a temporary facility (e.g., field 1025 hospital), the effective use of distance, exposure time, or non-structural shielding may eliminate 1026 the need for structural shielding. 1027

1028

1029 REQUESTING AND PERFORMING STUDIES INVOLVING X-RAYS 1030

1031 The following section uses the terms Referring Medi cal Practitioner and Radiological Medical 1032 Practitioner. The Referring Medical Practitioner i s a health professional who, in accordance with 1033 state and federal requirements, may refer individua ls to a Radiological Medical Practitioner for 1034 medical exposure (IAEA 2011b). The Radiological Me dical Practitioner is a health professional, 1035 with education and specialist training in the medic al uses of radiation, who is competent to 1036 independently perform or oversee procedures involvi ng medical radiation exposure in a given 1037 specialty (IAEA 2011b). 1038

1039 REQUESTING STUDIES: REFERRING MEDICAL PRACTITIONERS (REQUESTING 1040 HEALTH PROFESSIONALS) 1041

1042 A medical procedure should only be performed on a p atient if it is appropriately justified and 1043 optimized for that particular patient. In this con text, “appropriateness” is generally defined in 1044 terms of benefit and risk. The RAND corporation ha s developed a definition of “appropriate” 104516

that is widely used: the expected health benefit (i .e., increased life expectancy, relief of pain, 1046 reduction in anxiety, improved functional capacity) exceeds the expected negative consequences 1047 (i.e., mortality, morbidity, anxiety of anticipatin g the procedure, pain produced by the procedure, 1048 misleading or false diagnoses, time lost from work) by a sufficiently wide margin that the 1049 procedure is worth doing (NHS 1993; Sistrom 2008). In other words, the anticipated clinical 1050 benefits should exceed all anticipated procedural r isks, including radiation risk. This implies that 1051

radiation should be included in the benefit:risk ev aluation for each patient both before and during 1052 any procedure. 1053

1054 As with any medical procedure, the requesting or “o rdering” provider (i.e., the Referring 1055 Medical Practitioner) should have adequate knowledg e of the patient, understand the nature of 1056 the proposed and alternative imaging procedures, an d fully comprehend the medical diagnostic 1057 and treatment options available in order to be able to assess the benefit:risk ratios for the imaging 1058 procedures. These ratios balance the benefit of th e diagnostic examination being requested 1059 against the stochastic and deterministic risks to t he patient from radiation exposure during 1060 imaging, as well as the benefits and risks from alt ernative radiological and non-radiological 1061 procedures. The Referring Medical Practitioner (wi th privileges at the facility/within the 1062 healthcare network for the ordering of radiographic studies) should have determined that 1063 sufficient clinical history, symptoms, signs, or fi ndings exist to necessitate the examination. All 1064 exposures to radiation should involve a benefit:ris k analysis, in order to ensure that the expected 1065 benefits of the examination outweigh the potential risks, and that the most appropriate 1066 radiological or non-radiological procedure is selec ted on the basis of its benefit:risk ratio. In all 1067 cases, the use of radiation in diagnostic medical i maging should be justified and optimized. This 1068 is the responsibility of all involved providers and technologists. Dose management begins when 1069 a patient is considered for a procedure involving i onizing radiation, involves equipment setup 1070 before the exam begins, and ends when any necessary radiation-related follow-up is completed. 1071

1072 Physicians and licensed independent practitioners ( Referring Medical Practitioners) who have 1073 the legal authority and privileges to request diagn ostic imaging studies involving ionizing 1074 radiation should have a basic understanding of radi ation effects and protection methods. Also, 1075 they should have an appreciation for the radiation dose involved in a study and the potential 1076 effects of this dose over the lifetime of the patie nt to properly assess the benefit:risk ratio. The 1077 justification of medical exposure for an individual patient should be carried out by the Referring 1078 Medical Practitioner, in consultation with the Radi ological Medical Practitioner when 1079 appropriate. Each health care facility should esta blish a formal mechanism whereby Referring 1080

Medical Practitioners have sources of information a vailable at the time of ordering regarding 1081 appropriate diagnostic imaging methods to answer th e clinical question and to optimize ionizing 1082 radiation dose to the patient. These may include d ecision support software or appropriateness 1083

criteria. A mechanism for consultation with Radiol ogical Medical Practitioners should also be 1084

made available. 1085

1086 One of the most important methods for reducing radi ation exposure is the elimination of 1087 clinically unproductive examinations. This continu es to be a significant, but largely unrealized 1088 opportunity. Appropriate education of the requesti ng physician, utilization of existing current 1089 recommendations (such as the ACR Appropriateness Cr iteria (ACR 2012)) and consultation with 1090 a Radiological Medical Practitioner prior to genera tion of the examination request can all 109117

improve the probability that the most appropriate e xamination is performed relative to the 1092 clinical question. Automated algorithms integral t o electronic ordering systems have the 1093 capability to alert the referring provider to more appropriate examinations, and can alert them to 1094 unnecessary repeat examinations. 1095

1096 Follow-up examinations are commonly done so that si gnificant changes in clinical information 1097 are obtained for making proper decisions on continu ation or alteration of the management of the 1098 patient. These examinations may result in unnecess ary patient exposure if repeated before 1099 significant changes in patient status occur; theref ore, it is recommended that they be done only at 1100 time intervals long enough to make proper decisions concerning continuation or alteration of 1101

treatment. 1102

1103 Qualifications to Request X-ray Examinations 1104

1105 Requests for imaging examinations involving the use of x-rays in Federal health care facilities 1106 should be made only by physicians or other Referrin g Medical Practitioners who are licensed in 1107 the United States or one of its territories or poss essions and privileged within the healthcare 1108 facility or network. Properly trained individuals such as physician assistants and persons in 1109 postgraduate medical training status do not have to meet the above requirements, but should be 1110 under the general supervision of a licensed physici an who does. 1111

1112 It is recognized that medical students, interns, re sidents, and some physician assistants may not 1113 have developed medical judgment as to which test wo uld be most efficacious. Such lack of 1114 experience is remedied by work under conditions whe re there is sufficient expert supervision and 1115 radiology providers available for consultation who can monitor the appropriateness of 1116 examinations based on the clinical history and can provide assistance. 1117

1118 In addition to the privileges for which broad quali fications are needed, there are a number of 1119 specialties which require only limited types of x-r ay examinations. For example, Doctors of 1120 Dental Surgery or Dental Medicine may request appro priate examinations of the head, neck, and 1121 chest, although such requests are normally confined to the oral region. 1122

1123 Variances to the above qualification requirements s hould occur only for emergency or life1124 threatening situations, such as natural disasters. Also, non-peacetime operations in the field or 1125 aboard ship could require such variances. Equipmen t designed for field use might need to be 1126 operated by those personnel available to assist in the performance of necessary medical, dental, 1127 and veterinary services. 1128

1129

PERFORMING AND SUPERVISING STUDIES: RADIOLOGICAL ME DICAL 1130

PRACTITIONERS AND TECHNOLOGISTS 1131

1132 Responsible use of medical, dental, and veterinary x-ray equipment involves restricting its 1133 operation to properly qualified and supervised indi viduals. Such a policy should be established 1134 for each x-ray facility by the responsible authorit y upon the recommendations of medical, dental, 1135 and veterinary staff. Eligible radiological medical practitioners include those who are granted 1136 privileges for equipment use on the basis of the ne eds of patients served by the facility. These 113718

are privileges to use radiation-emitting equipment and are separate from privileges to perform 1138 procedures. Such privileges might include, as part of their practice, the use of CT equipment by 1139 radiologists and cardiologists; the use of fluorosc opes by cardiologists, radiologists, urologists, 1140 and others; and the use of dental x-ray equipment b y dentists. Before radiological medical 1141 practitioners are granted equipment use privileges, it is strongly recommended that they receive 1142 adequate training in equipment use and radiation pr otection. However, specific protocols 1143 limiting equipment use privileges to specified type s of radiological medical practitioners should 1144 be part of the written policy statement. 1145

1146 After completion of an accredited educational progr am and certification by a state or voluntary 1147 credentialing organization, radiologic technologist s should be able to produce radiographic 1148 images with lower average patient doses than incomp letely-trained or non-credentialed 1149 operators. Non-credentialed operators may have lit tle or no formal training in anatomy, patient 1150 positioning, or radiation protection practices. In adequately trained operators are likely to 1151 irradiate patients and themselves unnecessarily (EP A 2000). Personnel responsible for image 1152 acquisition should be trained in patient preparatio n and positioning, selection of technique 1153 factors and acquisition parameters, radiation prote ction measures, routine equipment QC, digital 1154 image post-processing and image processing. They s hould also be able to reduce to a minimum 1155 the number of repeat examinations. Performance of imaging examinations by incompletely 1156 trained personnel is not justified except for emerg ent circumstances. 1157

1158 In order to achieve lower patient doses, the operat or’s manual should be readily available to the 1159 user, and equipment operation should be guided by t he manufacturer’s instructions, including 1160 any appropriate adjustments for optimizing dose and ensuring adequate image quality. 1161

1162

Radiological Medical Practitioners 1163

1164 A Radiological Medical Practitioner is a health pro fessional, with education and specialist 1165 training in the medical uses of radiation, who is c ompetent to independently perform or oversee 1166 procedures involving medical exposure in a given sp ecialty. Within the Radiology department, 1167 this individual is typically a radiologist. Other individuals who use ionizing radiation for 1168 imaging, usually outside the Radiology department ( e.g., cardiac catheterization or fluoroscopy 1169 in the operating room), are also considered Radiolo gical Medical Practitioners. These 1170 individuals, when acting as a Radiological Medical Practitioner, have the same responsibilities 1171 for imaging protocols and for supervising equipment operation that would otherwise be assigned 1172 to a radiologist. The Radiological Medical Practit ioner is also responsible for optimizing the 1173 dose of ionizing radiation. 1174

1175 Radiologists 1176

1177 A radiologist is a licensed physician or osteopath who is certified in Radiology or Diagnostic 1178 Radiology by the American Board of Radiology or the American Osteopathic Board of 1179 Radiology (AOBR), or has completed a diagnostic rad iology residency program approved by the 1180

Accreditation Council for Graduate Medical Educatio n (ACGME) or the American Osteopathic 1181 Association (AOA). Within the Radiology department , the radiologist generally serves as the 118219

Radiological Medical Practitioner. In addition to interpreting imaging studies, radiologists set 1183 protocols for examinations involving x-ray systems and play a critical role in the performance of 1184 studies. Imaging protocols should be devised for e ach imaging system and each imaging study. 1185 These protocols should provide adequate image and s tudy quality while optimizing the radiation 1186 dose, particularly to radiosensitive tissues. Cons iderations include identifying the appropriate 1187 area of coverage, collimation, number of views to b e acquired, and image quality needs (which 1188 dictates the required x-ray beam energy and intensi ty). For CT, this includes CT-specific 1189 technique factors, area of coverage, and the number of CT examination phases. Radiologists are 1190 a source of knowledge on the advantages and disadva ntages of different imaging modalities and 1191 should be consulted when that expertise is needed. 1192

1193 Medical Radiologic Technologists 1194

1195 Medical Radiologic Technologists (MRTs) and Registe red Cardiovascular Invasive Specialists 1196 (RCIS) having appropriate radiation and other train ing are the personnel who operate the 1197 imaging equipment, deliver the radiation to the pat ients and capture the diagnostic images. As 1198 such, they are extremely important in the optimized use of diagnostic imaging. Operator 1199 competence is normally achieved by successful compl etion of a training program which provides 1200 both a didactic base and sufficient practical exper ience. The training program should be 1201 accredited by a mechanism acceptable to the appropr iate credentialing organization, e.g., the 1202 American Registry of Radiologic Technologists or Ca rdiovascular Credentialing International 1203 (CCI). Continuing competence and professional grow th should be encouraged with specific 1204 opportunities to further the technologist's knowled ge and skills through attendance at workshops 1205 or by other means of training. 1206

1207 The radiologic technologist should be familiar with and facile at utilizing the imaging systems 1208 and the techniques and technology available to them to reduce patient radiation dose while 1209 producing clinically adequate images. As a critica l part of the healthcare team, they should be 1210 empowered to question techniques and requests when alternatives which would deliver lower 1211

doses are available. 1212

1213

SCREENING AND ADMINISTRATIVE PROGRAMS 1214

1215 Screening programs using ionizing radiation should be justified, and the doses should be 1216 optimized for screening. It is important to keep r equirements current with technological 1217 advances. There are several reasons why individual s without known disease or symptoms may 1218 be referred for imaging examinations. Some are spe cifically for administrative or occupational 1219 safety programs such as the annual postero-anterior chest radiograph acquired to evaluate for 1220 pneumoconiosis in coal, silica and asbestos workers . Self-referral by patients for screening 1221 imaging to evaluate for disease in the absence of s ymptoms is an increasingly common 1222 occurrence whose appropriateness should be weighed and the individual counseled on the 1223 benefits and risks. If screening has been shown to have a positive benefit:risk ratio, it is 1224 generally warranted. As an example, in 2012, one a ccepted screening program is mammography 1225 (ACR 2009b). Generally, neither screening nor elec tive x-ray examinations should be performed 1226

on pregnant women. 1227

122820

Chest Radiography 1229

1230 Screening for tuberculosis is no longer performed i n the United States with chest radiography, 1231 although this technique may still be required durin g disaster relief and humanitarian operations 1232 in other parts of the world. 1233

1234 “Routine” radiographs without specific indications or symptoms should not be performed on 1235 admission to the hospital or while an inpatient. 1236

1237 Standard postero-anterior chest radiographs are per formed periodically to evaluate certain 1238 populations with high occupational risk for lung di sease. These populations include coal miners, 1239 asbestos workers, silica workers and a few other sp ecific populations. There are typically 1240 specific requirements for these images; yet, as wit h all other images, it is important to optimize 1241

the radiation dose delivered to the individual. 1242

1243 Mammography 1244

1245 Breast cancer is a common and significant health ri sk in the United States. Because of the 1246 importance of early detection in control and surviv al, mammography is an important screening 1247 modality. This technique has improved considerably since the publication of Federal Guidance 1248 Report 9 (EPA 1976), especially with respect to red ucing radiation dose per examination. 1249 Women and their health care providers are encourage d to refer to the most current NCI 1250 recommendations when deciding upon breast cancer sc reening examinations. Mammography 1251 facilities must comply with the Mammography Quality Standards Act (MQSA) regulations 1252 (FDA 2012c). 1253

1254

REFERRAL AND SELF-REFERRAL EXAMINATIONS 1255

1256 There are two types of self-referral. One is patie nt self-referral, where patients refer themselves 1257 for an imaging procedure without having a physician request (referral). The other is physician 1258 self-referral where physicians see patients, decide to perform imaging procedures on those 1259 patients, and then refer the patients to themselves or their own medical practice for the 1260 procedure. 1261

1262 Patients Requesting Imaging on Themselves without a Referral from a Licensed 1263 Independent Practitioner (Referring Medical Practit ioner) 1264

1265 With the increased capabilities of imaging systems and particularly with CT imaging, there has 1266

been an increased interest in and demand for use of this technology to screen for pre-clinical 1267 disease in the general population. Such screening programs should be subjected to rigorous 1268 scientific evaluation, as has been done for mammogr aphy, to ensure that the risk posed to the 1269 population screened does not outweigh the benefits in detection of disease. 1270

1271 Physician Self-Referral 1272

1273 In this context, self-referral examinations are exa minations requested or ordered by the same 127421

physician who subsequently performs or interprets t hem. They are frequently performed by 1275 equipment operators lacking adequate training and h aving supervision by health professionals 1276 with inadequate radiologic experience. Some examin ations performed by non-radiologists may 1277 occur because of the convenience of having the x-ra y unit and the patient in the same location, 1278 or, in the case of civilian contract services, need to justify the equipment purchased or 1279

maintenance costs. 1280

1281 Unnecessary radiation exposure caused by self-refer ral practices that are not diagnostically 1282 relevant generally need not occur in Federal health care institutions where facilities staffed by 1283 radiologists are normally provided. Exceptions cou ld be small operational units, such as ships, 1284 field units, or isolated stations where the normal workload does not justify a staff radiologist. 1285 Thus, the conduct of self-referral x-ray examinatio ns should be permitted only by a physician 1286 whose qualifications to supervise, perform, and int erpret diagnostic radiologic procedures have 1287 been demonstrated to the appropriate authorities. 1288

1289 It is recognized that limited self-referral type ex aminations are performed in Federal medical 1290 centers in certain clinical specialties. The use o f such self-referral x-ray examinations should, 1291 however, be limited to studies unique to and requir ed by the specialty of the physician 1292 performing them and be consistent with a peer revie w policy. 1293

1294 Self-referral practices in federal facilities are e xpected to be immune to economic considerations 1295 for the referring physician. Self-referral practic es in contract civilian facilities can lead to 1296

overutilization due to economic incentives for the referring physician and should be prohibited. 1297 Exception may be made in remote areas where no prac ticable alternative exists. 1298

1299

COMMUNICATION AMONG PRACTITIONERS 1300

1301 Optimal medical care requires appropriate interacti on between the Referring Medical Practitioner 1302 and the Radiological Medical Practitioner. The inf ormation technology system also plays an 1303 important role. Requests for x-ray examinations sh ould be considered as medical consultations 1304 between the Referring Medical Practitioner and the Radiological Medical Practitioner. A request 1305 should state the diagnostic objective of the examin ation and should detail relevant medical 1306 history including results of previous diagnostic x- ray examinations and other relevant tests. 1307

1308 Whenever possible the Radiological Medical Practiti oner should review all examination requests 1309 requiring fluoroscopy, CT, or other complex or high -dose studies before the examination is given 1310 and preferably before it is scheduled. For this re ason, it is important that a thorough and accurate 1311 patient history be included with each examination r equest. Based upon the clinical question, 1312 history, and relevant available previous studies, t he Radiological Medical Practitioner should 1313 direct the examination using standard protocols, wi th any appropriate addition, substitution, or 1314 deletion of views or sequences. It is preferable t hat changes in the examination be done in 1315 consultation with the Referring Medical Practitione r. 1316

1317 Effective communication of the findings is an essen tial component of imaging studies. Facilities 1318 are strongly encouraged to have policies on the com munication of findings that are consistent 1319 with the guidelines of accrediting organizations an d professional societies (ACR 2010). 132022 1321 The provision of care by more than one medical faci lity may result in duplication of imaging 1322 studies. To prevent this, and as technology permit s, the Referring Medical Practitioner should 1323 review the patient’s medical record to determine wh ether the proposed imaging study would 1324 duplicate a previous study. This requires that the reports and images from all studies are 1325 accessible through the patient’s Electronic Health Record (EHR) (Congress 2007). 1326

1327 When referral from one facility to a second is anti cipated, only the studies needed for proper 1328 referral should be performed in the first facility. Those imaging studies should be made 1329 available to the second medical facility concurrent with the transfer, either electronically or in 1330 hard copy format. 1331

133223

TECHNICAL QUALITY ASSURANCE IN MEDICAL IMAGING WITH X-RAYS 1333

1334 Quality assurance refers to those steps that are ta ken to make sure that a facility consistently 1335 produces images that are adequate for the purpose w ith optimal patient exposure and minimal 1336 operator exposure. Quality assurance may be divide d into two major categories: quality 1337 administration and quality control. 1338

1339 Quality administration refers to the management asp ect of a quality assurance program. It 1340 includes those organizational steps taken to make s ure that testing techniques are properly 1341 performed and that the results of tests are used to effectively maintain a consistently high level of 1342 image quality. An effective program includes assig ning personnel to determine optimum testing 1343 frequency of the imaging devices, evaluate test res ults, schedule corrective action, provide 1344 training, and perform ongoing evaluation and revisi on of the quality assurance program. 1345

1346 Quality control comprises the procedures used for t he routine physical testing of the primary 1347 components of the imaging chain from the x-ray sour ce, through processing, to the viewing of 1348 images, as addressed in Table 1. Each facility, th rough its radiation quality control team (e.g. 1349 qualified physicist and biomedical maintenance pers onnel), needs to track maintenance and 1350 monitoring procedures. 1351

1352 Each facility performing medical imaging with x-ray s should establish in writing and implement 1353 a technical quality assurance, quality administrati on, and quality control program that conforms 1354

to the most recent version of the “ACR Technical St andard for Diagnostic Medical Physics 1355 Performance Monitoring of Radiographic and Fluorosc opic Equipment” (ACR 2006b) and the 1356 “ACR Technical Standard for Diagnostic Medical Phys ics Performance Monitoring of Computed 1357 Tomography (CT) Equipment” (ACR 2007b). The progra m should include all aspects of the 1358 imaging process from image acquisition through imag e display. For film-screen imaging, it 1359 should include film and chemical expiration dates a nd storage requirements, monitoring of film 1360 processing, dark-room conditions, cleaning of inten sifying screens, the cleaning and performance 1361 of view boxes, the ambient viewing conditions in ro oms used for image interpretation, and image 1362 repeat analysis. For imaging with solid state imag e receptors such as computed radiography and 1363 direct radiography, it should include testing calib ration of the CR plate readers and direct digital 1364 detectors, cleaning and inspection of CR plates, im age repeat/reject analysis, calibration of 1365 detector exposure indices, monitoring of doses to t he image receptors(exposure indices), 1366 uniformity of the sensitivity of the image receptor inventory, cleaning and monitoring of the 1367

luminance and calibration of video monitors used fo r initial image QC and interpretation, and the 1368 ambient viewing conditions in rooms used for image interpretation. Monitors for interpretation 1369 of grayscale images should be calibrated to the DIC OM Grayscale Standard Display Function 1370 (NEMA 2009). These quality assurance measures are addressed in the Radiography section 1371 under Testing and Quality Assurance. 1372

1373 TECHNIQUE FACTORS 1374

1375 Technique factors should be established for each im aging procedure. For radiographic 1376 examinations, these include kV, mAs and exposure ti me if automatic exposure control is not 1377 used, and perhaps choice of image receptor. For CT examinations, these include kV, mA, 137824

rotation speed, pitch, selection of a mode in which mA is modulated during the scan (if 1379 available), and degree of noise reduction (if avail able). Technique factors may be programmed 1380 into the imaging device, or they may be manually se lected. If they are programmed in, 1381 programming should be consistent across all similar devices at a facility. Technique factors 1382 should be chosen that produce a clinically-adequate image at the least dose to the patient, not an 1383 ideal image. Whenever possible, technique factors should be adjusted to the thickness of the 1384 patient. 1385

1386 If the review of technique factors used clinically or the comparison of dose indices indicates that 1387 an optimum balance has not been achieved between pa tient dose and image quality or that 1388 patient doses exceed national standards, the techni que factors, whether posted in a chart or 1389 programmed into the imaging device, and/or selectio n of image receptor, should be modified as 1390

necessary. 1391

1392 TESTING BY A QUALIFIED PHYSICIST 1393

1394 It is strongly recommended that the technical quali ty assurance program includes testing by a 1395 qualified physicist of all imaging equipment produc ing x-rays. The equipment should be tested 1396 after installation but before first clinical use, a nnually thereafter, and after each repair or 1397 modification that may affect patient dose or image quality. Testing after repair or modification 1398 should be performed before clinical use of the equi pment. The testing, including a summary of 1399 methods, instruments used, measurements and deficie ncies identified, should be documented in a 1400 written report signed by the qualified physicist. The testing should include the items in Table 1 1401

below: 1402 1403

Table 1. Testing Frequency of Imaging Equipment tha t Produces X-Rays

TASK INITIAL AFTER

MODIFICATION OR REPAIR (a) ANNUAL

Measure radiation output parameters, including beam intensity and beam quality X X X

Test modes of operation used clinically, such as automatic control systems (e.g., automatic exposure controls of radiographic systems, automatic exposure rate controls of fluoroscopy systems.) X X X

Assess image quality X X X Determine Detector Exposure Index Accuracy (b) X X X

Evaluate the accuracy of patient dose or dose

rate indicators X X X

Assess the typical patient dose delivered for various examinations for comparison to national

reference levels X X X

Perform an acceptance test X X25

Table 1. Testing Frequency of Imaging Equipment tha t Produces X-Rays

TASK INITIAL AFTER

MODIFICATION OR REPAIR (a) ANNUAL

Review the overall technical quality control

program X

Perform a periodic review of all CT protocols (c) X X (a) Testing following repairs or modifications may be l imited to features and parameters that would be affected by the repairs or modification. (b) Determine accuracy of detector exposure indice s according to AAPM TG116 methodology (AAPM 2009) and manufacturer’s recommendations if a vailable. (c) The review of CT protocols should be performed together by the radiologist, CT technologist, and medical physicist. Consider staggering annual reviews throughout the year to maintain momentum without impacting schedules.

1404 The qualified physicist may be assisted by other pr operly trained persons in obtaining test data 1405 for performance monitoring. These persons should b e trained by the qualified physicist in the 1406 techniques for performing the tests, the function a nd limitations of the imaging equipment and 1407 test instruments, the reasons for the tests, and th e importance of the test results. The qualified 1408 physicist should be present at the facility for the initial and annual testing and should promptly 1409 review, interpret, and approve all data measurement s and test results. 1410

1411 EQUIPMENT FAILURE 1412

1413 When x-ray imaging equipment fails to meet the perf ormance specifications, the equipment 1414 should be promptly adjusted or repaired to correct the deficiency or should be removed from 1415

clinical use. A written or electronic record shoul d be kept of the correction of such deficiencies 1416 in accordance with the organization’s record keepin g policy. The record should include the date 1417

of correction and the action taken to correct the d eficiency. 1418

1419

DEFICIENCY CORRECTION VERIFICATION 1420

1421 After correction of deficiencies that affect patien t dose or image quality, the equipment should be 1422 tested promptly, by or under the supervision of a q ualified physicist, to verify that the deficiency 1423

was corrected and that the correction did not cause other deficiencies. 1424

1425

DOSIMETRY 1426

1427 Patient dose indices, measured at clinically-used t echnique factors by or under the supervision of 1428 a qualified physicist, should be available for revi ew. For radiography, entrance skin exposures 1429 for common projections should be listed for a patie nt of typical thickness. For fluoroscopy 1430 systems that have appropriate dosimetry measurement capabilities (e.g., air kerma or dose area 1431 product), the accuracy should be measured and recor ded. For fluoroscopy systems that do not 1432 have dosimetry indicators, the typical and maximal entrance skin exposure estimates should be 1433 measured and recorded for each fluoroscopic mode of operation for small, average, and large 1434 patient thicknesses. 143526

REFERENCE LEVELS 1436

1437 The primary purpose of an imaging study using ioniz ing radiation is to answer a clinical question 1438 or assist in making a diagnosis. Production of suc h a study results in two determinants: the 1439 qualitative evaluation by the health professional o f the clinical value of the study, and the amount 1440 of radiation exposure required to conduct it. Each study should be evaluated for acceptable 1441 quality by a qualified individual (technologist or Radiological Medical Practitioner). A 1442 representative sampling and assessment of exposure indicators from each modality should be 1443 performed at least annually, but preferably quarter ly, by a radiologic technologist under the 1444 guidance of a qualified physicist. 1445

1446 Reference levels (RLs) are values used as quality a ssurance and quality improvement tools. 1447 Quality improvement uses quantitative and qualitati ve methods to improve the safety, 1448 effectiveness, and efficiency of health care delive ry processes and systems. Left unchanged, a 1449 system will produce the same results it has been ac hieving or degenerate. To achieve a higher 1450 level of performance, the system must be changed. 1451

1452 RLs were first introduced in the 1990s (ICRP 2003; Wall and Shrimpton 1998). RLs are used to 1453 help avoid radiation dose to the patient that does not contribute to the medical imaging task 1454 (ICRP 2003). They are intended to provide guidance on what is achievable with current good 1455 practice rather than optimum performance, and help identify unusually high radiation doses or 1456 exposure levels (ACR 2008b; IAEA 1996). RLs are a guide to good practice, but are neither 1457 dose limits nor thresholds that define competent pe rformance of the operator or the equipment 1458 (Vañó and Gonzalez 2001). For assessments where th e dose metric is determined using a 1459 phantom, a value above the reference level requires investigation. On the other hand, for 1460 interventional procedures, if the mean dose metric for a number of cases of a procedure exceeds 1461 the reference level, it does not always mean that t he procedure has been performed improperly. 1462 Similarly, a mean dose metric for a procedure that is less than the reference level does not 1463 guarantee that the procedure is being performed opt imally (Vañó and Gonzalez 2001). 1464

1465 These levels are based on exposure to a standard ph antom or actual patient dose metrics for 1466 specific procedures measured at a number of represe ntative clinical facilities. RLs are set at 1467 approximately the 75 th percentile (third quartile) of these measured data . The use of RLs is 1468 supported by national and international advisory bo dies (Amis et al. 2007; ICRP 2000a). These 1469 and other organizations have provided guidelines on measuring radiation dose metrics and 1470 setting reference levels (IAEA 1996; ICRP 1991a; IC RP 1996; ICRP 2007c; Wall and Shrimpton 1471 1998). RLs can be specific to the country or regio n, and may be derived from multinational, 1472 national or local data (ICRP 2003; ICRP 2007b). As of 2012, U.S. reference levels are not 1473 available for most imaging studies. In order to ge nerate national RLs for the U.S., it is essential 1474 that institutions where these procedures are perfor med submit radiation dose metrics to a central 1475 dose registry. 1476

1477 Each institution or individual practitioner should use reference levels as a quality improvement 1478 tool by collecting and assessing radiation dose dat a. Standard phantoms are used where the 1479 procedure is standardized (e.g., chest radiograph o r head CT). Patient dose metric data are 1480 collected if the procedure is individualized for ea ch patient (such as fluoroscopically guided 148127

interventions) and should be collected for standard ized procedures as well. The mean radiation 1482 dose for the examination is then compared to the re ference level for that examination (ICRP 1483 2003). If the mean radiation dose at the facility exceeds the reference level, equipment and 1484 clinical practices should be investigated in order to reduce radiation doses (NRPB 1990; Wall 1485 2001). Equipment function should be investigated f irst, followed by review of the clinical 1486 protocol (Vañó and Gonzalez 2001). Investigations are also appropriate where local values are 1487 substantially below the RLs, as excessively low dos es may be associated with poor image quality 1488 (Balter et al. 2008; IAEA 2009). As appropriate, o perator performance may be assessed if no 1489 other cause is found. The development of reference levels requires consideration of the 1490 technique factors which most affect patient exposur e. The Nationwide Evaluation of X-ray 1491

Trends (NEXT) is a program conducted by the Food and Drug Administration (FDA) in 1492 conjunction with the States and the Conference of R adiation Control Program Directors 1493 (CRCPD) (FDA 2010a). The NEXT data provide a profi le of aspects of medical and dental 1494 imaging using ionizing radiation in the United Stat es at the time of survey. These data provide a 1495 window into clinical practice because they reflect the myriad of combinations of imaging 1496 equipment, technique factors, and the skills of equ ipment operators. Therefore, regardless of the 1497 specific details of technique or combinations of al l these factors, the frequency distributions of 1498

dose derived from the NEXT data were assumed to be sufficiently representative of the complex 1499 interaction of Referring Medical Practitioner prefe rence, Radiological Medical Practitioner 1500 preference, operator technique, and x-ray equipment performance for each of the selected 1501 standard examinations. Thus, NEXT data, when avail able and current, serve as a useful source 1502 for the development of national reference levels in the U.S. (ACR 2008b). 1503

1504 Professional organizations in the U.S., such as the American College of Radiology (ACR 2008b) 1505 and the American Association of Physicists in Medic ine (Gray et al. 2005), support the use of 1506 third quartile values of particular dose indices. It is important, however, to emphasize that with 1507 good technique, practicable levels of exposure for most patients will be below these levels. 1508

1509 The ICRP considers RLs a useful tool to help optimi ze patient radiation dose in fluoroscopically 1510 guided interventional (FGI) procedures (ICRP 2007c) . As of 2012, some studies have presented 1511 RLs for cardiovascular procedures (Balter et al. 20 08; D'Helft et al. 2009; Neofotistou et al. 1512 2003; Peterzol et al. 2005) and a limited number of interventional radiology procedures (Aroua 1513 et al. 2007; Brambilla et al. 2004; Hart et al. 200 9; Miller et al. 2009; Tsalafoutas et al. 2006; 1514 Vano et al. 2008a; Vano et al. 2009; Vano et al. 20 08b; Verdun et al. 2005). Unfortunately, the 1515 observed distributions of patient doses for most ty pes of FGI procedures are very wide, because 1516 the dose for each instance of a procedure is strong ly dependent on individual clinical 1517 circumstances. A potential approach is to include the ‘complexity’ of the procedure in the 1518 analysis (Balter et al. 2008; IAEA 2009; ICRP 2007c ). Since, as of 2012, complexity cannot be 1519 quantified (with the exception of some intervention al cardiology procedures), this adjustment is 1520 not possible for FGI procedures (Balter et al. 2008 ; IAEA 2009). Because of the high individual 1521 variability of patient dose in cases of FGI procedu res, the number of cases recommended in the 1522 literature as sufficient to provide adequate radiat ion dose data for a single facility varies from 10 1523 to >50 (Vano et al. 2008a; Wall and Shrimpton 1998)

. 1524

1525 It is expected that U.S. reference levels will decr ease over time as outlier institutions improve 1526 their equipment and practices. In the United Kingd om, reference levels derived from data in the 152728

2000 review were approximately 20% lower than those derived from data in the 1995 review and 1528 approximately half of those determined in the mid-1 980s (Hart et al. 2009). 1529

1530 For each type of examination there exists, within a vailable technology, an optimal combination 1531 of imaging equipment and technique factors to produ ce adequate images at doses below the 1532 reference level. Hence, it is important to evaluat e each system’s performance to determine 1533 whether dose is optimized and to maintain this by e stablishing appropriate procedures and 1534 conducting periodic monitoring. 1535

1536

1537

GUIDANCE BY DIAGNOSTIC AND INTERVENTIONAL MODALITY 1538

1539

INTRODUCTION 1540

1541 Except in emergency situations, informed consent sh ould be obtained from the patient or the 1542 patient’s legal representative and appropriately do cumented prior to the initiation of any 1543 procedure that is likely to expose the patient, or fetus if the patient is pregnant, to significant 1544 risks and potential complications. When obtaining informed consent for image-guided 1545 procedures using ionizing radiation that are known to be potentially high dose, an estimation of 1546 the anticipated risks from the radiation dose shoul d be communicated to the patient as part of the 1547 overall discussion of risks (NCRP 2010). When a de lay in treatment would jeopardize the health 1548 of a patient and informed consent cannot be obtaine d from the patient or the patient’s legal 1549 representative, an exception to obtaining informed consent is made (ACR 2006a). 1550

1551 Once the physician or dentist determines that the p rescription of an x-ray examination is 1552 warranted for diagnostic purposes, other factors be come important in limiting patient exposure. 1553 Optimization of patient dose may not be accomplishe d, even when well-designed equipment is 1554 used, unless appropriate quality assurance programs exist to keep it functioning properly and 1555 those who operate it are properly qualified to use the features of the equipment. These latter 1556 considerations are discussed in the chapter on Tech nical Quality Assurance in Medical Imaging 1557 with X-Rays. To ensure that x-ray equipment used i s justifiably representative of present day 1558 technological advances, authorities should develop and periodically review a planned 1559 replacement schedule for all types of diagnostic x- ray equipment used in their programs. 1560

1561 All x-ray equipment used for the imaging of humans for medical purposes should be maintained 1562 so that it conforms, throughout its useful lifetime , to applicable FDA regulations (FDA 2012g). 1563 Furthermore, users should be aware of upgrades to s oftware and hardware that enhance safety. 1564 These should be evaluated and considered for implem entation. 1565

1566 The qualifications of x-ray imaging equipment opera tors should be defined by the responsible 1567 authority in a written protocol which details: 1) w ho may operate x-ray imaging equipment and 1568 the supervision required, 2) the education, trainin g, and proficiency requirements for x-ray 1569 imaging equipment operators, and 3) requirements fo r continuing education and demonstration 1570 of proficiency. This policy should be reviewed and revised as required. 1571

1572 Prior to each examination requiring ionizing radiat ion, there should be a pre-procedure 157329

“verification” that patient identity, intended proc edure and positioning, and equipment are 1574 correct. Also, the technologist should confirm tha t the patient, if female, is not pregnant and 1575 that, if contrast media is to be used, the patient is not allergic to it. Invasive procedures and CT 1576 examinations require both pre-procedure “verificati on” and “time-out” processes. Those 1577 processes should be as specified by The Joint Commi ssion for invasive procedures under the 1578 Universal Protocol (The Joint Commission 2012a; The Joint Commission 2012b). 1579

158030

RADIOGRAPHY 1581

1582 General radiography is a service usually provided b y a Radiology Department, either in a central 1583 department or satellite facilities. Requests (orde rs) for general radiography services are 1584 performed based on protocols for standard views of each anatomic area, modified, if needed, to 1585 suit special requests or circumstances. Authorized variations to these protocols should be made 1586 for patient age and body habitus. Each medical cen ter should have a written policy for the safe 1587 use of radiographic equipment. This policy should apply to all radiographic equipment, whether 1588 fixed or portable. This policy should: 1589

1590

1. require testing of the radiographic equipment by a qualified physicist (or under their 1591 guidance for facilities or locations where it is no t practicable to provide such staffing), 1592

2. require training and credentialing of persons opera ting or directing the operation of 1593 radiographic equipment, and 1594

3. specify procedures for the safe use of the equipmen t, including dose management and 1595 recordkeeping. 1596

1597 Equipment 1598

1599 Beginning in the 1990s, a transition occurred from film-screen radiography to digital 1600 radiography (radiography using other image receptor s). These newer image receptor 1601 technologies include storage phosphor plates and se veral direct-image-capture technologies. All 1602 of these digital radiography technologies produce d igital images that are most commonly viewed 1603 on video monitors, although the images may be print ed on film using a laser printer, chemically 1604 developed, and examined on a view box. 1605

1606 With film-screen radiography, there is feedback to the technologist if technique factors, primarily 1607 mAs, result in an excessive exposure to the patient . The pertinent measure of the response to 1608 radiation exposure is the optical density of the fi lm. Optical density is a non-linear function of 1609 radiation exposure. In film-screen radiography, wh en imaging a specific projection of a 1610 particular patient, only a narrow range of patient exposures will produce an adequate image. An 1611 exposure greater than this range produces an “overe xposed” film with excessive optical density 1612 and inadequate image contrast, and an exposure belo w this range produces an “underexposed” 1613 film with excessively low optical densities and ina dequate image contrast. Thus, provided that 1614 an appropriate x-ray tube voltage is used and the film is properly developed, the choice of film1615 screen combination largely determines the radiation exposure to a patient of a given size. 1616

1617 There are advantages and disadvantages to digital i mage receptors in comparison to film-screen 1618 receptors. Digital receptors respond to radiation over a wide range of exposures. The statistical 1619 noise in the image varies with the exposure, with h igher exposures producing images with 1620 relatively less statistical noise. One of the many advantages is that the wide range of exposures 1621 permits the exposure for a particular image to be m atched to the clinical task – for an imaging 1622 procedure in which more statistical noise can be to lerated, a lower exposure can be used. 1623 Another advantage is that images acquired with over ly high exposures and some of those 1624 acquired with overly low exposures may still be use ful, avoiding retakes. An image acquired 162531

with an excessively low exposure will have excessiv e statistical noise, but this may not render 1626 the image uninterpretable. 1627

1628 There are also disadvantages to digital radiography . Digital image receptors facilitate acquiring 1629 multiple images, which may encourage the acquisitio n of more images than are clinically 1630 necessary. As of 2012, radiography with storage ph osphor plates may require significantly 1631 larger patient exposures, by a factor of 1.5 to 2, than rare-earth phosphor film-screen systems to 1632 produce images of equivalent quality (Compagnone et al. 2006; Seibert et al. 1996). In digital 1633 radiography, an excessive exposure decreases statis tical noise and will likely produce an image 1634 that is of higher quality than needed for the clini cal task. Furthermore, it may not be apparent to 1635 either the technologist or the Radiological Medical Practitioner that the exposure was excessive. 1636 Thus, there may be a tendency for technologists to routinely use unnecessarily high exposures, a 1637 phenomenon called “dose creep” or “exposure creep” (Freedman et al. 1993; Seibert et al. 1996; 1638 Willis and Slovis 2005). Excessive exposures are e specially likely when using manually selected 1639 technique factors instead of automatic exposure con trol. Examinations made using storage 1640 phosphor plates and mobile radiographic machines ar e particularly susceptible to excessive 1641 exposures. Excessive exposures can also occur due to improper calibration of the automatic 1642 exposure control system, the incorrect configuratio n of protocols, or the use of an inappropriate 1643 protocol when automatic exposure control is used. Deliberate use of a protocol that provides an 1644 excessive exposure to avoid retakes or criticisms d ue to underexposure should be avoided. 1645

1646 Testing and Quality Assurance 1647

1648 Quality assurance measures for radiographic imaging using film-screen image receptors are well 1649 established, and are described in several publicati ons (AAPM 2006b; ACR 2006b; NCRP 1650 1989b). These measures include, among others, clea ning of image intensifying screens; 1651 establishing technique charts for exposures; and mo nitoring film processing, darkroom 1652 conditions, film storage, retakes, inadequate image s, view boxes, and viewing conditions. 1653 Digital radiography retains some of the quality ass urance issues seen with film screen image 1654 receptors, eliminates others, and adds new ones (AA PM 2005; AAPM 2006a; ICRP 2004). 1655

1656 Storage phosphor image receptor systems and many di rect image capture systems provide the 1657 capability to monitor the exposure to the image rec eptor from each individual imaging exposure, 1658 with a quantity termed the exposure indicator. The exposure indicator relates to receptor 1659 exposure, and not directly to patient dose. As of 2012, each manufacturer of these systems 1660 defines, calculates, and names their exposure indic ator differently. These proprietary exposure 1661 indicators are not consistent. Some are proportion al to the exposure and others are proportional 1662 to the logarithm of the exposure. Some increase as the exposure to the image receptor increases 1663 and others decrease as the exposure increases. A s tandard indicator of exposure to the image 1664 receptor (called the Exposure Index) for adoption b y all manufacturers was developed and 1665 published in 2009 and adopted by the International Electrotechnical Commission (AAPM 2009; 1666 IEC 2008). Each facility should have a program for monitoring indices of exposure to image 1667 receptors, and work toward adopting the standard in dex when feasible after it is adopted. 1668 Facilities should work with their Radiological Medi cal Practitioners and qualified physicists to 1669 develop procedures and establish target Exposure In dex values and respective Deviation Index 1670 ranges by category of examination and patient popul ation. 167132 1672 Quality assurance measures should be adopted for di gital radiography (ACR 2007a). Table 2 1673 below in the procedures section lists these measure s. 1674

1675 It is strongly recommended that radiographic techni que factors be established for common 1676 procedures. These either should be programmed into the x-ray machine or a technique chart 1677 should be immediately available to the operator. B ecause of the phenomenon of dose creep, the 1678 use of appropriate technique factors is especially important in digital radiography. The technique 1679 factors for imaging protocols should be optimized f or the age and size of the patient, and for the 1680 imaging task. Although a qualified physicist can a ssist with this process, protocol optimization 1681 also requires the efforts of a Radiological Medical Practitioner. This process can benefit from 1682 the involvement of a technologist and the vendor, a s well. It is particularly important to optimize 1683 the technique factors for radiographic imaging prot ocols performed on infants and children since 1684 the preset vendor protocols may result in unnecessa ry radiation dose. 1685

1686 Pediatric imaging imposes additional concerns. It is strongly recommended that particular 1687 attention be paid to dose optimization for pediatri c patients. For pediatric patients the operator 1688 should determine the need for an anti-scatter grid (if removable) and patient immobilization. 1689 Collimation should be adjusted appropriately and te chnique charts should be used for those body 1690 parts that do not cover the sensor of the automatic exposure control device. 1691

1692

Personnel 1693

1694 Each person who directs the operation or operates r adiographic equipment should be trained in 1695 the safe use of radiographic equipment, in order to ensure adequate image quality and optimize 1696 patient dose. Also see the section on PERFORMING A ND SUPERVISING STUDIES: 1697

RADIOLOGICAL MEDICAL PRACTITIONERS AND TECHNOLOGIST S. 1698

1699 Radiological Medical Practitioner 1700

1701 Radiographic equipment should be operated under the general supervision of a physician. This 1702 individual fulfills the responsibilities of the Rad iological Medical Practitioner. Depending on the 1703 study, the responsible physician may be a radiologi st, a surgeon, a cardiologist, a 1704 gastroenterologist, or another medical specialist. This individual should be appropriately trained 1705 in the imaging modality, should be familiar with th e principles of radiation protection, and 1706 should have a sufficient understanding of the medic al imaging modality’s features to determine 1707 the appropriate protocol to evaluate the patient’s clinical symptoms. 1708

1709 Technologist 1710

1711 The technologist is responsible for using facility- approved imaging protocols and radiation 1712 protection measures. Technologists should be train ed to produce adequate quality radiographic 1713 images and to assist in the quality assurance progr am. They should also be able to optimize 1714 various technique factors of the x-ray equipment to produce an adequate radiographic image at 1715 the lowest practicable patient dose and to use opti mal procedures in working with patients and 1716 ancillary equipment to reduce to a minimum the numb er of repeat examinations. Some operators 171733

have little or no formal training in anatomy, patie nt positioning, or radiation protection practices. 1718 Performance of x-ray examinations by these inadequa tely trained individuals is not justified 1719 except for emergencies. 1720

1721

Other personnel 1722

1723 Only personnel with specific, appropriate training should be permitted to operate x-ray 1724 equipment. The use of x-ray equipment by other ind ividuals is warranted only in an urgent or 1725 emergent situation when qualified personnel as spec ified above are not available to perform the 1726 examination in a timely fashion. 1727

1728

Procedures 1729

1730 It is strongly recommended that a radiologist provi de general supervision in facilities performing 1731 radiography. A board certified radiologist is pref erred. Periodic review of the radiographic 1732 images should be performed as part of the routine q uality assurance process. 1733

1734 X-ray examinations should be performed in accordanc e with approved imaging protocols. The 1735 technologist should not perform any examination whi ch has not been requested by an authorized 1736

person. 1737

1738

Collimation restricts the useful beam to the clinic al area of interest. Collimation to exclude body 1739 areas not being examined should be used to minimize unnecessary exposure. Masking portions 1740 of a digital image is not a substitute for collimat ion. 1741

1742 If it does not interfere with the examination, cont act or shadow shielding, using leaded aprons or 1743 other shields, should be employed to shield those p arts of the patient that are particularly 1744 radiosensitive and are within the primary beam. Go nadal shielding should be used as 1745 appropriate. It is strongly recommended that breas t shielding be used for scoliosis examinations 1746 on girls and young women. All shields should be pl aced between the x-ray source and the tissue 1747 to be shielded. When shielding is used, an automat ic exposure control sensor should be selected 1748 that is not within the shadow of the shield, or man ual exposure control should be used. 1749

1750 A written outline containing the minimum number of views to be obtained and the equipment to 1751 be used for each requested examination should be ma de available to each Radiological Medical 1752 Practitioner and equipment operator in every radiol ogy facility. Beyond the specified minimum 1753 views, the examination should be individualized acc ording to a patient's needs. 1754

1755 The outline of procedures should indicate who may a uthorize deviations from the standard set of 1756 views for any examination. Every effort should be made to reduce to a minimum the number of 1757 standard views for any examination. The necessity of additional views, such as comparison 1758 views, should be determined by the Radiological Med ical Practitioner. 1759

1760 A periodic review of all standard examination proce dures should be performed to determine if 1761 the established routine is achieving the objectives and whether modifications are warranted. 176234

Continuation of a standardized examination procedur e should be predicated on satisfying the 1763 following criteria: 1764

1765

1. the efficacy of the examination is sufficiently hig h to assure that the diagnosis could not 1766 have been made with less risk by other non-radiolog ical means or a smaller number of 1767 views, 1768

2. consideration of previous similar examinations perf ormed with multiple views established 1769 that in a significant number of the cases all views were necessary for the diagnoses 1770 rendered, and 1771

3. the yield or outcome of the examinations offsets th e radiation exposure delivered. 1772

1773 A periodic review should be performed at least annu ally by experts designated by departmental 1774 leadership, and with the input of referring physici ans. These reviews should consider applicable 1775 regulations as well as the consensus and advice of professional societies concerning the efficacy 1776 of radiologic examinations. 1777

1778 Other quality assurance measures are listed in Tabl e 2 below. The specifics of these measures 1779 may change over time. The user should consult the relevant AAPM testing protocols. 1780

Table 2. Quality Assurance Measures for Film and Di gital Modalities

Film-Screen Radiography

Task Frequency Methodology Physicist testing See Table 1 See section on Technical Quality Assurance in Medic al Imaging with X-Rays. Processor Monitoring Daily Clean crossover racks an d perform sensitometry test. Darkroom Cleaning Weekly Check for dust, clutter, e tc.

Processor Preventive

Maintenance Monthly Perform deep cleaning and evaluate darkroom chemicals as recommended by the manufacturer. Screen Cleaning Monthly Clean all screens in invent ory according to manufacturer’s

recommendations Repeat Analysis Quarterly Track the repeat/reject r ate and ensure it is less than or equal to 7% (NCRP 1988). Trends indicating deterio ration in performance or increase in patient dose should b e investigated. Darkroom Fog Annually Lightly expose a film (image a step wedge at 70 kVp, 5 mAs). In the darkroom with safelight on, cover hal f the latent image with an opaque material for at least 2 minutes then develop the film. A visible line between the two parts of the image indicates a darkroom fog problem. Film-Screen Contact Test Annually Follow film-scree n contact test tool instructions.

Review Local Radiation Protection and Quality Control Operating

Instructions Annually Revise as needed.35 1781 Computed Radiography

Task Frequency Methodology Physicist testing See Table 1 See section on Techni cal Quality Assurance in Medical Imaging with X-Rays. Image Plate Erasure Weekly, or daily if

unsure of

status Perform primary erasure of each plate following

manufacturer’s instructions. This should be perfor med before use if the status of the plate is unknown or fogging is anticipated. Plates in storage do not require eras ing until used (AAPM 2006a). Quality Control Phantom Image Acquisition Monthly Follow manufacturer’s recommendations.

Transmit Phantom Image to Interpreting Medical Treatment Facility (MTF) Monthly For Teleradiology Sites Only: After acquis ition of QC image, transmit to interpreting MTF for verificatio n of image quality. Operator Console At least Monthly View and evaluate QC pattern (AAPM 2005), clean

monitors. Repeat Analysis Quarterly Track the repeat/reject r ate and ensure it is less than or equal to 7% (NCRP 1988). Trends indicating deterio ration in performance or increase in patient dose should b e investigated. Dose Monitoring Quarterly Review patient dose indic es according to manufacturer’s

recommendations. Detector Exposure Index Monitoring Quarterly Review exposure indicators according to A APM TG116 methodology (AAPM 2009) and compare with guidance levels. One source for appropriate guidance levels may be

the manufacturer. Image Plate Inspection and Cleaning Quarterly Follow manufacturer’s recommendations for proper cleaning technique using approved cleaning solution and proper safety precautions.

Review Local Radiation Protection and Quality Control Operating

Instructions Annually Revise as needed.

1782 Direct Digital Radiography

Task Frequency Methodology Physicist testing See Table 1 See section on Technical Quality Assurance in Medic al Imaging with X-Rays. Quality Control Phantom Image Acquisition Weekly Follow manufacturer’s recommendations.

Operator Console At least Monthly View and evaluate QC pattern (AAPM 2005), clean

monitors.36

Direct Digital Radiography

Task Frequency Methodology Transmit Phantom Image to Interpreting MTF Monthly For Teleradiology Sites Only: After acquis ition of QC image, transmit to interpreting MTF for verificatio n of image quality. Repeat Analysis Quarterly Track and trend the repea t/reject rate and ensure it is less than or equal to 7% (NCRP 1988). Dose Monitoring Quarterly Review patient dose indic es according to manufacturer’s

recommendations. Detector Exposure Index Monitoring Quarterly Review exposure indicators according to A APM TG116 methodology (AAPM 2009) and compare with guidance levels. One source for appropriate guidance levels may be

the manufacturer.

Review Local Radiation Protection and Quality Control Operating

Instructions Annually Revise as needed.

1783 Interpretation and QC Display Monitors

Task Frequency Methodology

User task: Visual assessment using QC test

pattern Daily AAPM TG-18 Online Report 3, table 8a or equiv alent (AAPM 2005)

Physicist, technologist tasks: Display system performance Monthly/ Quarterly AAPM TG-18 Online Report 3, table 8b or equivalent

(AAPM 2005)
Physicist tasks: display system calibration

verification Initially

and Annually AAPM TG-18 Online Report 3, table 8c, or equivalent

(AAPM 2005)

Monitor cleaning Monthly

and as

needed Clean monitors with cleaner approved by manufacture r

1784

Other External Equipment

Task Frequency Methodology Printer quality control See methodology Follow manufacturer’s recommendations

Digitizer quality control See methodology Follow manufacturer’s recommendations

1785

1786

178737

FLUOROSCOPY 1788

1789 Fluoroscopy may be employed by a variety of service s in a medical facility to guide procedures, 1790 including imaging. It can be performed with fixed, mobile or portable fluoroscopy systems. 1791 Some fluoroscopically guided procedures can deliver a large radiation dose to the patient, even 1792 when used properly. Prolonged procedures may resul t in injury, including non-healing ulcers, 1793 and other tissue injuries (FDA 1994). Because staf f must remain with the patient in the 1794 procedure room during fluoroscopy, their potential occupational radiation dose is non-trivial. 1795 Each medical center should have a written policy fo r the safe use of fluoroscopic equipment. 1796 This policy should apply to all fluoroscopy equipme nt, whether fixed, mobile, or portable, e.g., 1797 mobile C-arm systems and mini C-arm systems. This policy should 1798

1799

1. require testing of the fluoroscopic equipment by or under the direction of a qualified 1800 physicist, 1801

2. require training and credentialing of persons opera ting or directing the operation of 1802 fluoroscopic equipment, 1803

3. specify procedures for the safe use of the equipmen t, including dose management and 1804 recordkeeping, and 1805

4. require a clinical QA/QI program for fluoroscopy. 1806

1807 Although the aggregate population effective dose is larger from the use of general purpose 1808 diagnostic equipment and CT, the highest organ dose s (especially skin doses) to individuals, 1809 other than in radiation oncology, generally result from interventional fluoroscopic procedures. 1810 These procedures may require high exposure rates fo r long periods of time; thus, it is of utmost 1811 importance that Federal health care facilities give particular attention to fluoroscopic 1812 examinations. Even for simple and low-dose fluoros copic examinations, proper training is 1813 required to perform the procedure with the optimal radiation dose. Therefore, x-ray equipment 1814 capability should not exceed the medical mission of the facilities, i.e., fluoroscopy should not be 1815 available in facilities where qualified medical per sonnel are not assigned. Equipment, physicians 1816 and staff should all meet current guidelines of the American College of Radiology Technical 1817 Standard for Management of the Use of Radiation in Fluoroscopic Procedures and its successors 1818 (ACR 2008c). 1819

1820 Equipment requirements and training requirements fo r operators differ depending on whether the 1821 procedures to be performed will be relatively low d ose or potentially high dose. 1822 Fluoroscopically guided procedures should be classi fied as potentially high radiation dose if 1823 more than 5% of cases of that procedure result in a n air kerma at the interventional reference 1824 point exceeding 3 Gy or a kerma-area product (KAP) exceeding 300 Gy-cm 2 . Low dose 1825 procedures are below these levels (NCRP 2010). 1826

1827 Equipment 1828

1829 If the medical mission requires fluoroscopy, only i mage-intensified units (with image intensifiers 1830 or flat panel detectors) should be used. As of mid -2006, all fluoroscopic equipment sold in the 1831 United States provides a final indication of air ke rma (proportional to radiation dose) at a 1832 reference point at the completion of the examinatio n. This simplifies the process of measuring 183338

and recording radiation dose in the medical record. 1834

1835 Some operative procedures, both minimally invasive and open surgical, performed both inside 1836 and outside the operating room, (e.g., hip replacem ent, transsphenoidal hypophysectomy, some 1837 endoscopic procedures) may require fluoroscopic ass istance. In general, these procedures tend to 1838 be relatively low-dose. For these procedures, to t he fullest extent practicable, only equipment 1839 with features such as last-image-hold and reduced d ose pulsed fluoroscopy, or equipment with 1840 similar dose-reducing features, should be used. Th e advantage of this technology is that the 1841 radiation exposure can be reduced compared to conti nuous fluoroscopy, while adequate image 1842 quality is maintained. 1843

1844 For procedures with a potential for high patient do ses (this includes most interventional 1845 radiology, interventional cardiology, interventiona l neuroradiology and endovascular surgical 1846 procedures), additional requirements apply for both equipment and personnel (Hirshfeld et al. 1847 2004; Lipsitz et al. 2000; Miller et al. 2003a; Mil ler et al. 2003b; Padovani and Quai 2005; 1848 Suzuki et al. 2006). Fluoroscopy equipment intende d for these procedures should, at a 1849 minimum, be compliant with the version of Internati onal Electrotechnical Commission Standard 1850 60601-2-43 (IEC 2010) applicable to the equipment a t the time of purchase. New fluoroscopic 1851 imaging systems should incorporate high heat-loadin g tubes, adjustable-rate pulsed fluoroscopy 1852 capability, spectral shaping filters, and automatic exposure control logic to optimize radiation 1853 dose and ensure adequate image quality throughout t he procedure. As future systems incorporate 1854 improved methods for both tracking and optimization of patient dose during fluoroscopically1855 guided procedures, purchasers and operators should take advantage of them when appropriate. 1856 The additional cost of dose-reduction technology is justified because the reduction in patient 1857

radiation dose can be considerable. 1858

1859 Proper patient management during fluoroscopically-g uided interventions requires appropriate use 1860 of the various features of the fluoroscopic equipme nt. This will permit patient dose to be 1861 optimized and staff dose to be minimized. There is an extensive literature on this subject which 1862 can be used for guidance (Chambers et al. 2011; Mil ler et al. 2010a; NCRP 2010; Stecker et al. 1863 2009; Steele et al. 2012). 1864

1865

Measurement or estimation of skin dose is desirable for all procedures which are high dose or 1866 have the potential to result in high patient dose. The quantity of interest is the peak skin dose 1867 (PSD), the highest dose at any point on the patient ’s skin. This determines the severity of a 1868 radiation-induced skin injury. Ideally, equipment should also provide the operator with a near 1869 real-time indication of skin dose, including PSD in the current radiation field. The operator 1870 would then be able to modify his/her technique duri ng the procedure to minimize skin dose 1871 (FDA 1994; Miller et al. 2002). Skin dose can be m easured with special films, an array of 1872 thermoluminescent dosimeters (TLDs), optically stim ulated luminescence (OSL) dosimeters or 1873 real-time point-measurement devices (Balter et al. 2002). Currently, these methods are 1874 expensive, cumbersome and inconvenient, and are not commonly used in routine clinical 1875 practice. In the future, software-based systems sh ould be able to estimate and map skin dose in 1876

real time. 1877

1878 Cumulative air kerma (cumulative air kerma at the r eference point; also called reference point 187939

dose, reference air kerma, reference point air kerm a, or cumulative dose) is measured in Gy and 1880 displayed automatically on all fluoroscopic equipme nt in the United States sold after mid-2006 1881 per 21CFR1020.32(k) (FDA 2012d). It is the dose at a pre-defined reference point. This point is 1882 separately defined for different types of fluorosco pic equipment (FDA 2012d; FDA 2012f). For 1883 C-arm units, this point is located along the centra l ray of the x-ray beam, 15 cm from the 1884 isocenter towards the x-ray source (IEC 2010). Cum ulative air kerma is not the same as skin 1885 dose. Cumulative air kerma is measured at a point in space that is fixed with respect to the 1886 gantry and can move with respect to the patient whe n the table is moved or the gantry is angled. 1887 Cumulative air kerma does not take table height or these motions into account. As a result, 1888 reference dose is usually greater than PSD (IEC 201 0; Miller et al. 2003a; Miller et al. 2012). 1889

1890 Kerma-area product (KAP, also called dose-area prod uct or DAP) is the product of the air kerma 1891

and the area of the irradiated field and is measure d in Gy·cm 2 . It does not change with distance 1892 from the x-ray tube. It is a good measure of the t otal energy delivered to the patient, and 1893 therefore a good measure of stochastic risk. It is not a good indicator of deterministic risk 1894 (Kwon et al. 2011; Miller et al. 2012). 1895

1896 Fluoroscopy time has been the standard dose metric. It is easy to measure and the capability to 1897 measure it is widely available. However, fluorosco py time does not reflect the effects of 1898 fluoroscopic dose rate or the radiation dose from f luorography (e.g., digital subtraction 1899 angiography or cinefluorography) and is a poor indi cator of patient dose. As recommended in a 1900 joint Society of Interventional Radiology/Cardiovas cular and Interventional Radiological Society 1901 of Europe (SIR/CIRSE) guideline, use of fluoroscopy time as the sole dose metric is not 1902 advisable, and should not be done unless no other d ose metric is available (Stecker et al. 2009). 1903 Even then, the number of images and cine frames sho uld also be recorded. Procedures with a 1904 potential for high patient doses should not be perf ormed using fluoroscopy equipment that is not 1905 compliant with IEC 60601-2-43 or its successors (IE C 2010). 1906

1907 For patient care and for quality assurance purposes , it is highly desirable for all radiation data to 1908 be transferred automatically to the PACS (picture a rchiving and communication system), RIS 1909 (radiology information system), and Electronic Heal th Record (EHR) as part of the study data 1910 (along with images and demographic information) if the fluoroscopy unit is connected to a 1911 PACS. These data should include the peak skin dose , if available; the cumulative air kerma from 1912 both fluoroscopy and from image acquisition, if ava ilable; the kerma-area product, if available; 1913 and the cumulative fluoroscopy time and number of i mages or cine frames recorded (Miller et al. 1914 2012; NCRP 2010). The IHE REM integration profile provides a standard for the transfer of 1915 such information to the PACS ((IHE 2008) or curren t version). 1916

1917 There are several relatively new technologies as of 2012 (e.g., cone-beam CT, surgical O-arms,) 1918 (ACR 2008c; Orth et al. 2008; Wallace et al. 2008). Others will certainly appear in future 1919 interventional fluoroscopy equipment. Some of thes e technologies are intended to provide 1920 greater technical capability for complex surgical o r interventional procedures. Currently, most of 1921 these technologies are designed to enhance the fluo roscopy unit’s surgical capability for 1922 procedures performed outside the Radiology Departme nt. Mobile equipment with these 1923 technologies is smaller in size than its convention al fixed counterpart, but it can be just as 1924 dangerous to the operator and patient. Facilities should establish procedures for the testing and 192540

use of these types of equipment, and for the traini ng and credentialing of its operators. 1926

1927 Testing and Quality Assurance 1928

1929 Equipment testing for quality assurance should be p erformed by or under the direction of a 1930 Qualified Physicist after installation but before f irst clinical use, annually thereafter, and after 1931 each repair or modification that may affect patient dose or image quality. Testing should be 1932 performed as specified in the section of this docum ent entitled Technical Quality Assurance in 1933 Medical Imaging with X-Rays. 1934

1935

Personnel 1936

1937 Fluoroscopy can deliver a significant radiation dos e to the patient, even when used properly. 1938 Also, fluoroscopy presents the potential for greate r radiation dose to the operator as compared 1939 with other imaging modalities. Therefore, all fluo roscopic examinations should be performed by 1940 or under the direct supervision of a physician with demonstrated competence, who has received 1941 training in fluoroscopy and has been privileged by the facility to perform fluoroscopy. 1942

1943 In fluoroscopy, the operator effectively determines , prescribes and delivers the required x-ray 1944 dose to the patient in real-time. These systems ar e often used to guide imaging or interventions 1945 and the exposure is directly related to the complex ity of the procedure and inversely related to 1946 the skill of the individual performing the procedur e. Individuals who are privileged for the use 1947 of these systems, and particularly the high dose ca pable systems as are used in interventional 1948 procedures should have a thorough understanding of the biological effects of radiation exposure, 1949 the dose from this radiation exposure and its likel y deterministic and stochastic risks, and of the 1950 available technique and technology based methods fo r minimizing the radiation dose to any 1951 portion of the patient’s tissue during the examinat ion. 1952

1953 Every person who operates or directs the operation of fluoroscopic equipment should be trained 1954 in the safe use of fluoroscopic equipment, in order to optimize patient dose. Initial training 1955 should include didactic training, hands-on training , and clinical operation under a preceptor. 1956

1957 Didactic training is a formal course of instruction in radiation saf ety which meets guidelines 1958 established by the responsible authority. It shoul d include the following topics: (a) physics of x1959 ray production and interaction; (b) the technology of fluoroscopy machines, including modes of 1960 operation; (c) characteristics of image quality and technical factors affecting image quality in 1961 fluoroscopy; (d) dosimetric quantities, units, and their use in radiation management; (e) the 1962 biological effects of radiation; (f) principles of radiation protection in fluoroscopy, (g) applicable 1963 federal regulations and agency requirements; and (h ) techniques for minimizing dose to the 1964 patient and staff. Completion of this phase of tra ining should include successfully completing a 1965 written examination. Radiologists may fulfill the didactic portion of the initial training through 1966 the extensive training in radiation physics, radiat ion biology and radiation safety they receive 1967 during their residency. 1968

1969 Hands-on training is conducted by a qualified individual who is fami liar with the equipment. 1970 Hands-on training means operation of the actual flu oroscope that is to be used clinically (or an 197141

essentially similar fluoroscope), including the use of controls, activation of various modes of 1972 operation, and displays. This phase of training co uld include demonstrations of the effect of 1973 different modes of operation on the dose rate to a simulated patient and could include 1974

demonstration of the dose-rates at various location s in the vicinity of the fluoroscope. 1975

1976 Clinical operation under a preceptor means operation of the fluoroscope for clinical pur poses 1977 under the direct supervision of a preceptor experie nced in the operation of the device. 1978 Completion of this phase of training should include written attestation, signed by the preceptor, 1979 that the individual has achieved a level of compete ncy sufficient to function independently as a 1980 fluoroscopy operator. 1981

1982 Training should be conducted initially and then at periodic intervals. Records should be kept of 1983 the training. The records should include the date( s) of training, the name(s) of the person(s) 1984 providing the training, the topics included in the training, the duration of the training, the test 1985 questions, the names of the persons successfully co mpleting the training, and the test scores of 1986 these persons. The training records should also in clude the signed preceptor statements 1987 described above. Training need not be performed at or by the medical facility, provided that the 1988 facility determines that it meets these requirement s and was sufficiently recent, and the facility 1989 obtains written certification of successful complet ion of the training. Periodic refresher training 1990 should include the didactic training. At the facil ity’s discretion, it may also include hands-on1991 operation and clinical operation under a preceptor physician. 1992

1993 Each person who operates or directs the operation o f fluoroscopic equipment should be 1994 privileged by the medical facility. Privileging sh ould be contingent upon successful completion 1995 of training as described above. Maintenance of pri vileges should be contingent upon successful 1996 completion of periodic refresher training and on co mplying with agency and facility 1997 requirements for the safe use of fluoroscopic equip ment. In particular, it is not permissible for a 1998 physician or other medical professional who has not completed this training, and who is not 1999 privileged, to direct the operation of a fluoroscop y unit even if it is operated by a radiologic 2000 technologist. 2001

2002 Operators who perform fluoroscopically-guided proce dures with the potential for high patient 2003 doses require additional knowledge and training bey ond that necessary for operators whose 2004 practice is limited to low-dose fluoroscopy procedu res (ICRP 2000a; Vano 2003). Operator 2005 knowledge includes all the information described in the current American College of Cardiology 2006 Foundation/ American Heart Association/ Heart Rhyth m Society/ Society for Cardiac 2007 Angiography and Intervention fluoroscopy clinical c ompetence statement and its successors . In 2008 general, radiologists and interventional cardiologi sts receive most or all of this information as 2009 part of their training, and are tested on this know ledge as part of the board certification processes 2010 by their respective Boards. Physicians in other me dical specialties may or may not have received 2011 training or been examined on this subject matter du ring their residency or fellowship, and may 2012 require additional training. 2013

2014

2015

201642

Procedures 2017

2018 Fluoroscopic procedures should be performed so that procedure dose is optimized and skin dose 2019 is minimized. This requires the appropriate use of various features of the fluoroscopic 2020 equipment. Further details are available in the pu blished literature (Miller et al. 2010b; NCRP 2021 2010; Sidhu et al. 2009; Stecker et al. 2009; Wagne r et al. 2000). 2022

2023

Dose measurement 2024

2025 Methods for estimating PSD can be ranked from most reliable to least reliable. As of 2012, peak 2026 skin dose measuring software is the most reliable, followed by measurement of cumulative air 2027 kerma, KAP, and finally fluoroscopy time combined w ith a count of the number of fluorography 2028 frames or images. Dosimeters placed on the skin ar e useful but can provide underestimates for 2029 PSD if placed outside the area of highest skin dose . This area may be quite small (Miller et al. 2030 2003a). PSD and KAP are now the most useful predic tors for deterministic and stochastic 2031 injury, respectively. Cumulative air kerma is read ily available on fluoroscopy units purchased 2032 after mid-2006 and is an acceptable substitute for PSD. It does not correlate well with PSD in 2033 individual cases (Miller et al. 2003a; Miller et al . 2003b). Fluoroscopy time alone does not 2034 correlate with PSD (Fletcher et al. 2002). Monitor ing fluoroscopy time alone also 2035

underestimates the risk of radiation-induced skin e ffects (O'Dea et al. 1999). 2036

2037 All statements of patient dose contain some degree of uncertainty. As of 2012, dose 2038 measurement accuracy in clinical units has an allow ed calibration accuracy of ±35% (FDA 2039 2012d). Even the most sophisticated dose-measureme nt instrumentation has unavoidable 2040

uncertainties related to variations in instrument r esponse with changes in beam energy, dose rate, 2041 and collimator size. Converting these measurements into skin dose introduces yet further 2042

uncertainties related to beam orientation and incon sistencies in the relationship between the 2043 patient’s skin and the interventional reference poi nt. Finally, clinically available dose and KAP 2044 measurements ignore the effect of backscatter from the patient. Backscatter causes the skin dose 2045 to exceed air kerma at the same location by 10 to 4 0%, depending on the beam area and energy 2046 (ICRU 2005, or most current version). Skin doses e stimated from reference dose, KAP, or 2047 fluoroscopy time may differ from actual skin dose b y a factor of two or more. Users of dose data 2048

should be aware of these uncertainties. Federal fa cilities should strongly encourage the purchase 2049 of equipment with features that enhance the accurac y and clinical value of dosimetry systems. 2050

2051 Recordkeeping 2052

2053 A record should be kept of each fluoroscopic proced ure. Whenever possible, this should be 2054 performed electronically, with automatic transfer o f the necessary data, as appropriate, from the 2055 fluoroscopy unit to a PACS, RIS, and EMR (see above , under Equipment ). The record should 2056 list the individual fluoroscopy unit, the date of t he procedure, the procedure (e.g., barium enema, 2057 iliac artery angioplasty and stent placement), info rmation identifying the patient, and the name of 2058 the physician operating or directing the operation of the device. The record should also list the 2059 cumulative air kerma from both fluoroscopy and from image acquisition, if available; the kerma2060 area product, if available; the cumulative fluorosc opy time and number of images recorded; and 2061 other dose metrics as they are developed. This rec ord should be maintained according to the 206243

Federal facility’s requirements. 2063

2064 It is strongly recommended that patient radiation d ose data be recorded in the patient’s medical 2065 record, including patient skin dose data whenever p ossible. Where and how these data are 2066 recorded is subject to the policies and procedures of the individual institution. However, the 2067 choice of dose metrics to be recorded should be gui ded by published recommendations, such as 2068 the guidelines on recording dose in the medical rec ord published by SIR (Miller et al. 2012; 2069 Miller et al. 2004; Stecker et al. 2009). 2070

2071 When the dose to one or more areas of a patient’s s kin may have exceeded a threshold dose for 2072 deterministic effects, the physician performing the procedure should be advised of this event and 2073 should place an appropriate notation in the patient ’s medical record (Stecker et al. 2009). The 2074

information should include information on the beam entry sites and the estimated skin dose for 2075 each, if available. Provisions should be made for clinical follow-up of those areas for monitoring 2076 radiation effects. The possibility of overlap of t wo separate adjacent fluoroscopic fields, where 2077 skin dose of the overlapping area may have exceeded the threshold dose, should be taken into 2078 account. Ideally, skin dose from radiation therapy and imaging modalities other than 2079 fluoroscopy should also be considered. It is recog nized that at the time this report was prepared, 2080 no simple method for measuring or estimating skin d ose is available. As a substitute, cumulative 2081 air kerma may be used. Threshold values recommende d by professional societies or advisory 2082 bodies, such as the ACR, SIR, ICRP and NCRP, should be consulted (ACR 2008c; ICRP 2000a; 2083 Stecker et al. 2009). As of 2012, these threshold values are typically a PSD of 3 Gy or 2084 cumulative air kerma of 3 – 5 Gy (ACR 2008c; NCRP 2 010). 2085

2086 Patient management 2087

2088 Management of patients who have received radiation doses high enough to cause deterministic 2089 effects should be guided by recommendations from ap propriate advisory bodies, medical 2090 specialty societies, and other organizations, and b y current practice (ACR 2008c; Balter and 2091 Moses 2007; Stecker et al. 2009). For these patien ts, this includes justifying and documenting 2092 the high radiation dose in their medical record, no tifying the patient or their health care proxy 2093 (legally authorized representative) of the radiatio n dose that has been administered and the likely 2094 consequences, and follow-up by the physician who pe rformed the procedure to determine 2095 whether a skin injury has occurred (Balter et al. 2 010). 2096

2097 Device related deaths, including those related to r adiation dose, must be reported by the device 2098 user facility to the device manufacturer and to the Food and Drug Administration in accordance 2099 with 21 CFR 803 (FDA 2012b). Device-related seriou s injuries, including those resulting from 2100 radiation, must be reported by the device user faci lity to the device manufacturer or, if the 2101 manufacturer is unknown, to the Food and Drug Admin istration. A serious injury is one that is 2102 life-threatening, results in permanent impairment o f a body function or permanent damage to a 2103 body structure, or necessitates medical or surgical intervention to preclude permanent damage or 2104 impairment (FDA 2012a). If a patient’s skin receiv es an absorbed dose that meets the Joint 2105

Commission definition of a reviewable sentinel even t from a fluoroscopically guided procedure, 2106 or a dose likely to result in a serious injury, the event also should be reported to the Radiation 2107 Safety Officer and the facility’s Patient Safety Ma nager, or designee (Balter and Miller 2007; 210844

The Joint Commission 2006). 2109

2110 Quality process 2111

2112 All QA/QI programs for interventional fluoroscopy s hould include patient radiation safety 2113 aspects. These include evaluation of operator perf ormance in dose optimization and of 2114 procedures where patients received a radiation dose that caused a radiation injury. 2115

2116 A review of radiation doses delivered to patients d uring fluoroscopically guided interventional 2117 procedures is an essential aspect of any performanc e improvement program. The dose metrics 2118 for all procedures should be reviewed at intervals (quarterly, for example) for their magnitude 2119

and for the dose distribution of these cases. This will provide a picture of dose utilization; any 2120 abnormally high doses can be reviewed for appropria teness. For example, doses can be 2121 compared to available reference levels. Any recomm endations and actions for improvement 2122 should then be implemented. 2123

2124 Analysis of overall dosimetric performance for inte rventional fluoroscopy procedures, 2125 incorporating the effects of equipment function, pr ocedure protocols, and operator performance, 2126 requires a different process than the reference lev els (RLs) used for radiography (NCRP 2010). 2127 It also requires a more detailed presentation of th e reference data set. Guidance data for an 2128 interventional fluoroscopy procedure are generated by obtaining data for all instances of that 2129 procedure from a number of different facilities. T hese data are used to generate Guidance Levels 2130 (GLs), which are similar to the RLs used for radiog raphy. The guidance data set includes the 2131 data for all instances of the procedure at each fac ility. This differs from the data set used to 2132 generate RLs, which typically includes only a singl e datum from each facility. 2133

2134 Guidance data sets for interventional fluoroscopy p rocedures usually demonstrate a lognormal 2135 distribution. The high dose tail is of particular interest, because this tail represents the cases 2136 where doses may be high enough to cause determinist ic effects. Because differences between 2137 the shapes of the collected guidance data and the l ocal facility data are potentially useful, the 2138 FGI-procedure guidance data set should characterize the entire distribution, rather than just the 2139

10 th and 75 th percentile values typically used for radiography R Ls. Also, in order to provide a 2140 basis for comparison for facilities that use locall y derived substantial radiation dose levels 2141 (NCRP 2010; Stecker et al. 2009), these data sets s hould indicate the percentage of instances of 2142 each procedure that exceed specific radiation dose levels. Ideally, these percentages should be 2143 presented at 0.5 Gy intervals from 2 Gy to the maxi mum value observed in the data set. 2144

2145 Guidance data and GLs can be used, to some extent, in a fashion similar to RLs, but the 2146 lognormal shape of dose distributions for intervent ional fluoroscopy procedures mandates that 2147 the local median (50 th percentile) be used for comparison with the guidan ce data, rather than the 2148 local mean dose. Also, high-dose interventional fl uoroscopy cases require further evaluation. It 2149 is possible for the facility’s median dose for a pr ocedure to be within an acceptable range (below 2150

the 75 th percentile of the guidance data) at the same time that there are an excessive number of 2151 cases with a radiation dose greater than the 95 th percentile of the guidance data. It is necessary to 2152 compare the percentage of cases at the facility tha t exceed the local substantial radiation dose 2153 level (the radiation dose level that triggers radia tion follow-up) with the percentage of cases in 215445

the guidance data that exceed the same level. Loca l percentages that are markedly above or 2155 below the value obtained from the guidance data sho uld be investigated (NCRP 2010). 2156

2157 The following method, using cumulative air kerma as the radiation dose metric, is suggested as 2158 one method of evaluating dose utilization for inter ventional fluoroscopy procedures (NCRP 2159 2010). It is not the only possible method. Kerma- area product could also be used to evaluate 2160 general dose performance. Kerma-area product can b e used to evaluate operator performance 2161 with respect to collimation. However, it does not provide an unambiguous identification of the 2162 cases where a very high skin dose may result in det erministic effects. 2163

2164 An appropriate published guidance data set for the selected procedure (the guidance data) is used 2165 as the starting point, although published guidance data for FGI procedures are sparse as of 2012 2166 (Balter et al. 2008; Bleeser et al. 2008; Brambilla et al. 2004; IAEA 2009; Miller et al. 2009; 2167 Vano et al. 2008a; Vano et al. 2009). 2168

2169 A facility should judge its dose performance for in terventional fluoroscopy procedures in several 2170 steps. The first step is to compare the local subs tantial dose radiation level to the guidance data. 2171 The facility’s local substantial radiation dose lev el is either a value taken from the literature 2172 (ACR 2008c; Mahesh 2008; Stecker et al. 2009) or a locally determined value. The percentage 2173 of procedures in the guidance data set that exceed this value can now be determined. 2174

2175 The next step is to characterize the dose distribut ion for all instances of a specific procedure 2176 performed at the facility. Evaluation of subsets o f these data sorted by procedure room and 2177 operator can be useful as well, as discussed below. The percentage of instances exceeding the 2178 local substantial radiation dose level, and the med ian value of the entire local data set (and 2179 appropriate subsets) is calculated. 2180

2181 The local median can be compared with the 10 th , 50 th (median) and 75 th percentiles of the 2182 guidance data. A median value below the 10 th percentile of the guidance data may indicate 2183 incomplete procedures. A median value between the 50 th and 75 th percentile of the guidance data 2184 could be due to clinical differences between the gu idance data population and the local facility 2185 population or other factors. Understanding the rel evant reasons may be useful. An investigation 2186

is warranted if the local median exceeds the 75 th percentile of the guidance data (IAEA 2009; 2187 NCRP 2010). This step is analogous to the analysis performed using RLs for radiographic 2188

examinations. 2189

2190 The percentage of instances exceeding the local sub stantial radiation dose level can be compared 2191 to the percentage of instances exceeding the substa ntial radiation dose level in the guidance data. 2192 Local percentages significantly above or below the value obtained from the guidance data should 2193 be investigated. 2194

2195 It can be useful to perform the same analysis using a reference dose value of 3 Gy as well as the 2196

local substantial radiation dose level. An interve ntional fluoroscopy procedure is in the 2197 potentially-high radiation dose category if more th an 5% of instances of that procedure exceed a 2198 reference dose of 3 Gy (NCRP 2010). If fewer than 5% of the instances of the procedure at the 2199 local facility exceed this value, then the procedur e, as performed at the local facility, is not in 220046

that category. At that local facility, the procedu re may be performed safely in a fluoroscopy 2201 suite that does not meet the requirements of IEC 60 601-2-43 (IEC 2010). Also, those procedures 2202 at the local facility that are not in the potential ly-high radiation dose category may be audited 2203 less frequently than those that are in that categor y. 2204

2205 Lastly, the overall distribution of the local data may be compared to the distribution of the 2206 guidance data. Displacement or distortion of the l ocal distribution histogram relative to the 2207 guidance data may be due to differences in equipmen t, clinical complexity, or other factors. 2208

2209 The analysis may be extended to individual operator s or interventional fluoroscopy procedure 2210 rooms by comparing operator- or room-specific data to either a facility’s local distributions or to 2211 pooled distributions of data for multiple facilitie s (e.g., (Miller et al. 2009)). Care should be 2212 taken in such an analysis to account for statistica l interactions (e.g., statistical confounding 2213 between the operator and the interventional fluoros copy procedure room). 2214

2215 Procedures resulting in a substantial patient radia tion dose should be reviewed on a regular basis. 2216 Reported potential radiation injuries should be rev iewed at the regular QA meeting, with any 2217 available diagnoses, planned patient follow-up, and outcomes. If a radiation injury occurred, the 2218 procedure should be reviewed for appropriate use of radiation in the clinical context. It may be 2219 appropriate to periodically re-report on the status of known radiation injuries. Additionally, 2220 reporting of these cases to the institution’s Radia tion Safety Officer is desirable. 2221

2222 Staff safety 2223

2224 Other than the patient who is being examined, only staff and ancillary personnel required for the 2225 procedure, or those in training, should be in the r oom during the fluoroscopic examination. No 2226 body part of any staff or ancillary personnel invol ved in a fluoroscopic examination should be in 2227 the primary beam (Miller et al. 2010b). If primary beam exposure is unavoidable, it should be 2228 minimized. As required by various states, all pers onnel in the room during fluoroscopic 2229 procedures should be protected from scatter radiati on by either protective aprons or whole-body 2230 shields of not less than 0.25 mm of lead-equivalent material. An apron with lead equivalence of 2231 at least 0.35 mm is recommended. Thyroid and eyes should be protected if the potential 2232 exposure to the worker will exceed 25% of the annua l regulatory dose limits for those organs. It 2233 is strongly recommended that protective aprons and gloves be evaluated at least annually for lead 2234 protection integrity (Miller et al. 2010b; NCRP 201 0). 2235

2236 Pregnant individuals involved in fluoroscopically g uided procedures generally do not need to 2237 limit their time in the procedure room to remain be low the dose limit for the embryo and fetus, as 2238 long as they use appropriate protective garments an d radiation protection methods, and their 2239 occupational exposure is adequately monitored (NCRP 2010). 2240

2241

2242

224347

COMPUTED TOMOGRAPHY 2244

2245 Computed tomography (CT) is an imaging modality tha t utilizes one or more x-ray beams to 2246 acquire projection images from many angles around t he patient. The projection images are 2247 mathematically manipulated to obtain tomographic im ages that depict x-ray attenuation in a two 2248 dimensional cross sectional, projectional or three dimensional representation of the subject’s 2249
anatomy. 2250

2251 There have been important technological advances th at have greatly increased the clinical 2252 usefulness of CT imaging. However, these improveme nts have also led to increased use of CT, 2253 imaging of larger volumes of the body, and acquirin g an increased number of image sequences 2254 either during the various phases of tissue enhancem ent following contrast injection or to 2255 dynamically evaluate areas affected by motion. The se are incredibly powerful diagnostic tools 2256 that are invaluable to patient management and allow the elimination of more dangerous invasive 2257 procedures, such as exploratory surgery. But with this great benefit has come a price: there has 2258 been an increase in radiation dose to the populatio n, as well as to the individual patient. 2259

2260 In the U.S., the number of CT procedures performed annually increased by 10% to 11% per year 2261 from 1993 to 2006 (NCRP 2009). Although CT procedu res comprise only about 17 % of all 2262 medical x-ray imaging procedures, they now impart a bout 49 % of the cumulative effective dose 2263 from medical procedures received by the population of the U.S. (Mettler et al. 2008). As of 2264 2012, a typical single CT imaging procedure of the chest, abdomen, or pelvis of an adult imparts 2265 an effective dose on the order of 3-7 mSv (McCollou gh 2008; Mettler et al. 2008). These values 2266 are for single phase exams and the effective doses for multiple phase exams are correspondingly 2267 larger. Thus, CT imparts some of the largest doses per procedure in diagnostic medical imaging. 2268 These doses are significantly exceeded only by the doses from some complex fluoroscopically2269 guided interventional procedures. 2270

2271 Except in the extreme circumstance of multiple irra diations of the same anatomic region, the 2272 doses from CT examinations are unlikely to cause de terministic effects such as erythema or 2273 epilation (hair loss). Instead, the main concern i s stochastic effects, particularly cancer. The ris k 2274 to the patient is determined mainly by the doses to organs in or near the scanned portion of the 2275 patient, the age and gender of the patient, and the likely remaining lifespan of the patient. 2276

2277 In 2001, it was reported that standard adult techni que factors were commonly used for CT 2278 imaging of patients in the U.S. regardless of body habitus, including children and even infants 2279 (Brenner et al. 2001; Paterson et al. 2001). If ad ult technique factors are used for imaging the 2280 abdomen or thorax of a small child or infant, the l arger doses together with the larger risk of 2281 cancer per unit dose is estimated to pose a risk of fatal cancer on the order of one per thousand 2282 examinations (Brenner et al. 2001). Therefore, it is essential to optimize dose when imaging 2283 children (FDA 2001). Of the many methods for adjus ting CT techniques for children, perhaps 2284 the simplest and most widely used techniques utiliz es the Breslow method familiar to clinical 2285 providers as a way to estimate the weight, drug dos ing, and equipment sizing for children. Many 2286 sites have developed specific CT protocols that adj ust the kVp and mAs based on the 2287 approximate size of a child matching each Breslow c olor scheme category. Professional 228848

societies provide excellent guidance on imaging, su ch as the “Image Gently” campaign (Goske 2289 MJ et al. 2008; Strauss et al. 2010). 2290

2291 Many advances in CT technique and technology have b een specifically targeted at reduction of 2292 the radiation dose delivered to the patient during CT examinations. To be effective, these 2293 techniques must be used, and used properly. It is imperative that Radiological Medical 2294 Practitioners, physicists, and technologists involv ed in CT imaging keep abreast of current 2295 developments and utilize all techniques available t o them to reduce the patient’s radiation 2296 exposure as much as possible while obtaining the cl inically needed information. 2297

2298 Equipment 2299

2300

CT was introduced in the mid-1970s. For several de cades, a constant x-ray tube current was the 2301 only available technology for performing a CT exami nation. Tube current did not change, 2302 regardless of the angle of the x-ray beam as the x- ray tube rotated around the patient, and 2303 regardless of the attenuation along the path of the beam through the patient. However, this 2304 attenuation varies greatly with the angle of the be am and the location on the patient’s body. As 2305 of 2012, developments in technology allow automated tube current modulation, providing 2306 similar image quality with lower radiation dose. F acilities should use equipment that provides 2307 relevant patient dose information. This equipment should allow the facility to program in dose 2308 alerts to inform operators if selected operating pa rameters might produce a radiation dose 2309 exceeding that recommended by the facility. Equipm ent manufacturers should incorporate these 2310 features into the equipment. 2311

2312 The dose of radiation to a patient, in conjunction with the attenuation provided by the part of the 2313 patient that is scanned and the presence or absence of IV contrast, determines the signal-to-noise 2314 ratio in the resultant images. The signal-to-noise ratio needed for diagnostic confidence depends 2315 upon the diagnostic task. Smaller and thinner pati ents require smaller doses than larger and 2316 thicker patients to produce similar signal to noise ratios in the images. Imaging procedures to 2317 detect or assess larger structures and structures w ith more inherent or enhanced contrast 2318 (difference in density) require a smaller dose than imaging procedures to detect or assess smaller 2319

structures and those with less inherent contrast. 2320

2321 Stand-alone CT scanners have been complemented by t he development of hybrid modalities such 2322 as Positron Emission Tomography/CT [PET/CT] and Sin gle Photon Emission Computed 2323 Tomography/CT [SPECT/CT]. These hybrid modalities use two equipment components to 2324 acquire two types of images of a patient in the sam e setting, without changing the patient’s 2325 position on the imaging system table. This allows co-registration of image data so that the 2326 anatomic detail provided by one imaging modality ca n be matched to the physiologic marker 2327 capability of the second modality to provide more s pecific information about the location and 2328 extent of disease. These CT devices may be operate d at lower doses if the CT portions of the 2329 exams are not intended to be used for diagnosis ind ependent of the SPECT or PET exam. 2330

2331 Technological development in image reconstruction, increases in computer processor power, 2332 equipment innovation, and optimization techniques i n general have led to a marked increase in 2333 the ability to obtain adequate quality images at lo wer patient doses. These improvements should 233449

be implemented to the fullest extent practicable. Facilities should use equipment that provides 2335 relevant patient dose information. This equipment should allow the facility to program in dose 2336 alerts to inform operators if selected operating pa rameters might produce a radiation dose 2337 exceeding that recommended by the facility. Equipm ent manufacturers should incorporate these 2338 features into the equipment. 2339

2340 Testing and Quality Assurance 2341

2342 Equipment testing for quality assurance should be p erformed after installation but before first 2343 clinical use, annually thereafter, and after each r epair or modification that may affect patient dose 2344 or image quality. Testing should be performed as s pecified in the section of this document 2345 entitled Technical Quality Assurance in Medical Ima ging with X-Rays. In addition, the 2346

recommendations found in the current version of ICR P Publication 102 (NCRP 1989b) should be 2347 followed when applicable. 2348

2349 A quality control program should be established. T he program should conform to the ACR 2350 Technical Standard for the Diagnostic Medical Physi cs Performance Monitoring of Computed 2351 Tomography (CT) Equipment or equivalent guidance. 2352

2353

Personnel 2354

2355 A CT system should only be operated by a Radiologic Technologist registered by the American 2356 Registry of Radiological Technologists (ARRT) or eq uivalent, preferably with advanced 2357 certification in CT, operating under the supervisio n of a Radiological Medical Practitioner with 2358 appropriate training in CT physics, radiation safet y and CT image interpretation. 2359

2360 Ideally, a PET/CT or SPECT/CT should be operated by a technologist certified in both nuclear 2361 medicine and CT. However, a PET/CT or SPECT/CT may also be operated by a nuclear 2362 medicine technologist with Certified Nuclear Medici ne Technologist (CNMT) or Radiological 2363 Technologist Nuclear qualified (RT(N)) certificatio n and additional training in CT imaging 2364 sufficient to safely operate a CT system. Alternat ively, a PET/CT may be operated by a 2365 technologist who is qualified to operate a CT syste m and who also has additional training in PET 2366 imaging sufficient to safely operate a PET system. If a technologist who meets these 2367 requirements is not available, the PET/CT or SPECT/ CT system should be operated by two 2368 technologists, one a nuclear medicine technologist qualified to operate the PET or SPECT 2369 system and the other a Diagnostic Radiological Tech nologist (DRT) or a therapist in radiation 2370 oncology who is qualified to operate the CT system. Utilization and training requirements for 2371 the operation of other hybrid modalities should be evaluated as new combinations of modalities 2372

emerge. 2373

2374

Procedures 2375

2376 One of the most effective ways to optimize the dose of radiation delivered to the patient in a CT 2377 study is to tailor the study to the patient’s speci fic needs. 2378

237950

A CT protocol specifies the parameters for the imag e acquisition and largely determines the dose 2380 to the patient. It defines the portion of the pati ent’s anatomy to be imaged, whether and how 2381 contrast agents will be administered, the number an d timing of imaging sequences, and 2382 acquisition technical parameters. Imaging sequence s in a multiphase study may include several 2383 phases, such as a pre-contrast phase, an arterial p hase, a venous phase and/or a delayed phase. 2384 Acquisition technical parameters may include pitch, collimation (beam width), kV, mA (constant 2385 or modulated), rotation time, physiologic gating, i mage quality factors, and reconstruction 2386

method. In addition: 2387

1. In some cases, the kV may be adjusted for the type of examination (e.g., contrast enhanced 2388 angiography) to accommodate patient size. 2389

2. If constant mA is selected, the protocol should uti lize a chart for adjusting the mA for the 2390 patient’s size (girth or thickness). If mA modulat ion is selected, the protocol should specify 2391 the parameters determining the balance between imag e noise and patient dose. 2392

3. Organ-specific tube current modulation, where avail able, technically feasible, and clinically 2393 appropriate, should be considered to protect organs such as the breast in younger female 2394 patients and the lens of the eye. 2395

4. Where applicable, the prescription of image acquisi tion technique factors should take into 2396 account the availability of advanced image reconstr uction techniques to decrease the 2397 required patient dose. 2398

5. Once the image sequence is acquired, the user can s elect alternative reconstruction 2399 parameters (e.g., reconstructed slice thickness) to view the images differently without 2400 having to rescan the patient. 2401

2402 Each CT protocol should be documented in two ways. The first way is a document detailing all 2403 relevant information. The second way provides a mo re limited subset of programmable 2404 information, primarily acquisition parameters, stor ed on the imaging device. 2405

2406 It is important to image only the area of anatomy i n question and acquire only the necessary 2407 sequences. This is accomplished by determining the imaging protocol for the examination. 2408 Where appropriate, the radiological medical practit ioner should select and adjust the protocol to 2409 ensure that the patient is examined using the appro priate techniques and dose. 2410

2411 The technologist performing the study is responsibl e for limiting the length of the patient being 2412 scanned to the minimum clinically necessary. The t echnologist is also responsible for setting up 2413 the CT system so that the correct protocol is used and the imaging parameters are appropriate for 2414 the patient’s size, age, and intended examination. Before performing the study, the technologist 2415 should confirm that the technical parameters and th e radiation dose metric are appropriate for the 2416 patient and planned study. If existing equipment d oes not provide a dose metric, efforts should 2417 be made to upgrade or replace it. To prevent accid ental overexposure, the projected dose should 2418 correspond to the doses normally associated with th e protocol, within reasonable variability. 2419 This should be confirmed again after the patient ha s been scanned. 2420

2421 Optimization of CT protocols is important for minim izing patient dose. The facility’s standard 2422 protocols for CT imaging should be reviewed by a te am, including a physician expert in CT 2423 image interpretation, a technologist expert in perf orming CT examinations, and a qualified 2424 physicist: 242551

1. when the protocol is developed, 2426

2. when the protocol is significantly modified, 2427

3. on a regular basis (preferably annually), and 2428

4. after an equipment upgrade or replacement. 2429

2430 It is strongly recommended that procedures be estab lished to avoid inadvertent or unapproved 2431 modification of CT protocols. Methods, such as lim iting access through the use of passwords, 2432 should be adopted to implement these procedures. S uperseded protocols should be archived for 2433

future reference. 2434

2435 Reviews and revisions should align protocols with c urrent clinical practice, evaluate the 2436 magnitude of delivered radiation doses, and optimiz e the radiation dose. Modifications of the 2437 protocol to suit the needs of an individual patient generally do not require a specific review, but 2438 the impact on radiation dose should be understood a nd considered. 2439

2440 Operator selectable parameters on CT scanners that affect the dose to the patient include the 2441 voltage applied to the x-ray tube (kV), the x-ray t ube current (mA) or current-time product per 2442 x-ray tube rotation (mAs), and the pitch (increment al table movement per x-ray tube rotation 2443 divided by the nominal x-ray beam width at isocente r). The radiation dose to the patient within 2444 the scanned volume is approximately proportional to the square of the kV and is proportional to 2445 the effective mAs (the mAs divided by the pitch). Technique factors should be appropriate for 2446 the size (and not just the age) of the patient and the body part being imaged. In particular, adult 2447 technique factors should not be used for children a nd infants. Technique factors should be 2448 chosen that produce a diagnostically adequate image rather than a “perfect image,” thus 2449 matching the radiation exposure to the diagnostic r equirement. If available on the CT scanner, 2450

automated modulation of the tube current should be used for those procedures for which it 2451 produces substantial dose savings, e.g., scans of t he thorax. Using this feature appropriately can 2452 reduce dose significantly, whereas errors in its us e have produced substantial increases in dose. 2453 For gated cardiac CT imaging, utilize (when availab le) the feature that reduces or terminates the 2454 beam current during portions of the cardiac cycle t hat will not be used for image reconstruction 2455 (ICRP 2012). 2456

2457 Several phantom-derived dose indices specific to CT have been defined. These can be useful to 2458 compare one study protocol to another in the assess ment of benefit and risk; these are described 2459 in the literature (McNitt-Gray 2002). Two indices in common use are the volumetric computed 2460 tomography dose index (CTDI VOL ), which is approximately the average dose in the s canned 2461 volume, and the dose-length product (DLP), defined as the CTDI VOL multiplied by the scanned 2462 length. These indices indicate the radiation expos ure delivered by the CT scanner to a phantom, 2463 not the specific radiation energy (i.e., dose) rece ived by any patient. Both of these measures may 2464 be available from current CT scanners, and future d evices may incorporate more accurate and 2465 useful dose metrics. The DLP and the portion of th e patient that is scanned (e.g., head, thorax, or 2466 abdomen) may be used to estimate the effective dose to the patient. Effective dose is an 2467

indicator of stochastic risk. CT dose indices shou ld be recorded as part of the patient record in 2468 the imaging study or medical record. 2469

247052

BONE DENSITOMETRY 2471

2472 Bone densitometry noninvasively measures certain ph ysical characteristics of bone that reflect 2473 bone strength, typically reported as bone mineral c ontent or bone mineral density. It is used for 2474 diagnosing osteoporosis and estimating fracture ris k. It is also used to monitor changes in bone 2475 mineral content, whether from age, conditions causi ng bone mineral loss, or treatment. Devices 2476

that measure bone mineral content are called bone densitometers . Non-invasive methods for 2477 measuring bone mineral content are based on the tra nsmission of x-rays or gamma rays through 2478 the bone. The radiation beams can be produced as p encil or fan beams. The advantage of the 2479 latter is that it is faster, but the radiation dose is increased by a factor of about 4. 2480

2481

There are also devices that use the transmission of sound waves through bone to assess bone 2482

structure. These are ultrasound devices that do no t directly measure bone mineral content, but 2483 are also commonly called densitometers. 2484

2485 Equipment 2486

2487 The principal methods in routine clinical use in 20 12 for the non-invasive measurement of bone 2488 mineral content using ionizing radiation include: x -ray absorptiometry and quantitative x-ray 2489 computed tomography (QCT). X-ray absorptiometers m easure attenuation of two x-ray beams 2490 of well-separated average photon energies to discri minate between bone mineral and soft tissue. 2491 This method is called dual-energy x-ray absorptiome try (DXA or DEXA). The other principal 2492 method for assessment of bone structure regarding o steoporosis is quantitative ultrasound (QUS) 2493 (ACR 2008a; Bonnick and L. 2006). 2494

2495 Of all the methodologies available in 2012, DXA is the only one that can be used to make a 2496 diagnosis of osteoporosis. The World Health Organi zation has developed criteria for diagnosing 2497 normal bone density, osteopenia, and osteoporosis ( Kanis et al. 1994). This classification is 2498 specific for DXA (total hip or femur and neck, PA l umbar vertebrae, or distal 1/3 radius) and 2499 cannot be applied to any other technology (ISCD 200 7a; ISCD 2007b). As of 2012, DXA is also 2500 the most commonly used technology for monitoring ch anges in bone mineral density (BMD). 2501 QCT is sometimes used to monitor changes in the tra becular portion of the vertebrae when there 2502 is a need to measure changes more frequently than w ith DXA. QCT, nevertheless, involves a 2503 much higher exposure to radiation, especially if do ne sequentially, and is more expensive and 2504 requires more specialized equipment and staff exper tise than DXA. 2505

2506 Bone mineral can be assessed non-invasively by thes e methods at several sites in the axial and 2507 appendicular skeleton. DXA is most commonly used t o assess the lumbar spine, proximal 2508 femurs, and distal radii. DXA measurements of the thoracic spine cannot be performed because 2509 the ribs overlap the thoracic vertebrae. Measureme nts of the proximal femurs are commonly 2510 referred to as “hip” measurements, but the bone min eral content measurements themselves are 2511 limited to the proximal femurs. DXA and SXA device s are available for measurements of 2512 peripheral sites such as the radius and the calcane us. The standard evaluation of bone mineral 2513 density includes evaluation of at least one proxima l femur and the lumbar spine in the frontal 2514 plane. 2515

251653

Some DXA devices are also capable of imaging the sp ine to detect vertebral fractures. This is 2517 called vertebral fracture assessment (VFA). Detect ion of vertebral compression fractures is an 2518 independent method for diagnosing osteoporosis. Th is is performed with imaging of the thoracic 2519 and lumbar spine in the lateral plane. Exposure to radiation is higher with VFA than with DXA 2520 but still considerably lower than for conventional radiography of the same area (Genant et al. 2521 1996). 2522

2523 Some DXA devices allow the C-arm holding the x-ray tube and detector to rotate to a position 2524 permitting lateral bone mineral density measurement s of the lumbar spine in the supine patient, 2525

in addition to the usual PA or AP measurements. So me DXA devices permit the acquisition of 2526 projection images of the entire lateral spine for v ertebral morphometry. Furthermore, some 2527 DXA devices permit PA or AP scans of the entire bod y for body composition analysis, providing 2528 an estimation of total bone mineral mass, lean body mass, and fat mass. 2529

2530 QCT measurements are usually performed of the lumba r spine, but there are options to perform 2531

measurements at other anatomical sites as well. Un like DXA, QCT is able to differentiate 2532 mineral content in the bone as opposed to mineral c ontent outside bones, such as in osteophytes 2533 or aortic calcifications. The presence of these ex tra-osseous calcifications makes the use of 2534 DXA of the vertebrae less reliable in older people. QCT, on the other hand, is able to focus on 2535 the trabecular or cortical component of bone. QCT may be performed with a standard CT 2536 system; however, a special phantom and software are needed. QUS is used to measure sites in 2537 the appendicular skeleton, most commonly the calcan eus. 2538

2539 Testing and Quality Assurance 2540

2541 Each facility performing bone densitometry should h ave a quality assurance program. The 2542 procedures for this program should be documented in writing. The program should conform to 2543

manufacturer’s recommendations and recommendations of professional societies such as the 2544 International Society for Clinical Densitometry (IS CD) and the American College of Radiology. 2545

2546 The quality assurance program should include daily assessments of accuracy and periodic 2547 assessments of precision. Cross calibration should be performed whenever the densitometer is 2548 repaired, modified, or replaced. This helps ensure proper measurement of bone mineral content, 2549 detection of osteoporosis, estimation of fracture r isk, and changes over short and long periods of 2550 time (i.e., minutes and years) even as equipment is repaired, modified, or replaced. 2551

2552 Accuracy check 2553

2554 Accuracy is the degree to which a measurement value estimates the actual value of the quantity 2555 being measured. The test for accuracy primarily me asures equipment characteristics. Most 2556 densitometers will not allow a DXA scan to be perfo rmed unless the accuracy test is passed. 2557 Phantoms are available and an accuracy assessment s hould be obtained daily. 2558

2559

2560

2561

256254 Precision 2563

2564 Precision is the degree to which the same value is obtained when a measurement is repeated 2565 (Bonnick and L. 2006; ISCD 2012). The better the p recision, the smaller the Least Significant 2566 Change (LSC), and the more likely is the detection of small changes in BMD. Precision studies 2567 assess the technologist’s skills at positioning the patient reproducibly. Several patient factors 2568 affect positioning, including obesity, arthropathie s, pain, deformities, fractures, and other 2569 conditions limiting patient mobility. Phantoms are not available for assessing precision; this is 2570 due to the complexity of relating phantom data to p atient results. Given these clinical variables 2571 and lack of appropriate phantom, precision studies should be conducted on subjects who are 2572 representative of the bulk of the population scanne d at the particular facility. For instance, if 2573 most patients scanned in a facility are over the ag e of 65 years, precision studies should not be 2574 done in that facility on young athletes. Each faci lity should establish a range of acceptable 2575 precision performance and ensure that each technolo gist meets this standard. If a facility has 2576 more than one technologist, an average precision er ror combining data from all technologists 2577 should be used to establish precision error and LSC for the facility. 2578

2579 For DXA, precision is affected by the positioning o f patients. Therefore, precision assessments 2580 should be performed using repeated measurements of patients, with repositioning of the patients 2581

between measurements. Precision studies can be don e on either 30 patients scanned twice (after 2582 the patient is repositioned in between scans) or 15 patients scanned 3 times, also after 2583 repositioning in between each scan (ISCD 2012). Th e technician’s or facility’s precision is then 2584 used to calculate the Least Significant Change (LSC ) to determine whether an observed change 2585 in BMD over a period of time is significant (higher than LSC) or not (less than the LSC). The 2586 patients imaged for precision studies should be rep resentative of the facility’s patient population. 2587 Retraining should occur if a technologist's precisi on is worse than values recommended by 2588 professional societies, e.g., ACR and ISCD. 2589

2590

Cross calibration 2591

2592 Cross-calibration is a method to derive equivalent BMD values when measured on the original 2593

densitometer and a modified or new densitometer. C ross-calibration should be performed when 2594 repairing, modifying, or replacing the entire syste m or any portion of the system that might alter 2595

the absolute BMD value. The old and new densitomet ers should be cross-calibrated to establish 2596 a new baseline. As with precision assessments, pha ntoms are not available for cross calibration. 2597 Cross-calibration is conducted in-vivo by scanning 60 to 100 patients with a wide range of bone 2598 densities (normal to osteoporosis) on both the old and new densitometer. A cross-calibration 2599 equation is then developed (by using linear regress ion methods), and can be used to predict the 2600

BMD value on the different densitometer. 2601

2602 Justification for quality assurance studies 2603

2604 Patients enrolled in precision studies benefit indi rectly and may benefit directly because these 2605 studies improve the reliability of the results. Pa tients enrolled in cross calibration studies benefi t 2606 directly in that these processes allow a better com parison with future scans done on the same or 2607 different equipment. It is in a patient’s best int erest to be scanned in a facility where precision i s 260855

high and LSC small, as the results are more reliabl e and comparisons with other scans more 2609 meaningful. 2610

2611

Precision and cross-calibration studies conducted b y scanning patients are not research. Thus, 2612 these studies do not need approval of an institutio nal review board. However, the facility should 2613 obtain informed consent from each patient participa ting in a precision or cross-calibration study. 2614 Although each scan results in a low effective dose to the individual patient, radiation doses to the 2615 individual patient can be reduced by scanning a lar ger number of patients a fewer number of 2616 times and by not including a patient in both precis ion and cross-calibration studies. Patients or 2617 staff should not be scanned solely for the purpose of training. 2618

2619 Cross-calibration should be performed when changing the entire system or any portion of the 2620 system that might alter the absolute BMD value. 2621

2622 Patient radiation dose should be determined by a qu alified physicist or a qualified medical health 2623 physicist after installation, after service that ma y affect the radiation dose, and at least annually 2624

thereafter. 2625

2626 In most cases, structural shielding will not be req uired for DXA or SXA devices or for QCT 2627 devices designed for use only on the appendicular s keleton. Nonetheless, the radiation safety 2628 officer or a qualified physicist should make a dete rmination whether shielding is needed. After 2629 device installation, whether or not additional shie lding is installed, dose measurements should be 2630 made in adjacent areas and at the operator’s statio n (which may be inside the room) and should 2631 be documented in a written report. This will help determine the need for occupational dosimetry 2632 and provide a historical record to ensure proper eq uipment functioning. 2633

2634

Personnel 2635

2636 Technologists performing absorptiometry should have documented formal training in the use of 2637 the absorptiometry equipment they are operating, in cluding performance of all manufacturer2638 specified and facility quality assurance (QA) proce dures. Each person performing bone 2639 densitometry should meet the State licensing requir ements in addition to at least one of the 2640 following qualifications: 2641

1. be a Diagnostic Radiologic Technologist (DRT), 2642

2. be certified by the American Registry of Radiologic Technologists (ARRT) in Nuclear 2643 Medicine Technology, 2644

3. be certified by the Nuclear Medicine Technology Cer tification Board, 2645

4. be certified by the International Society of Clinic al Densitometry as a Certified 2646 Densitometry Technologist, 2647

5. have ARRT post-primary certification in Bone Densit ometry, or 2648

6. have state licensure or limited licensure in Bone M ineral Densitometry, when the licensure 2649 requires successful completion of the ARRT Limited Scope Bone Densitometry 2650

Examination. 2651

265256

Interpretation of the results is important and the interpreting Radiological Medical Practitioner 2653 should be knowledgable in bone densitometry. Relia nce on the report generated by the 2654 equipment alone is inadequate. Clinicians should a lso examine the plates and raw data. 2655

2656

Procedures 2657

2658 Organizations that use bone densitometry should ref er to current versions of procedures or 2659 position statements issued by professional organiza tions (ISCD 2007a; ISCD 2007b). The 2660 following guidance applies to DXA scans. 2661

2662 Before the DXA scan, the technologist should: 2663

1. Ensure that the various quality assurance parameter s have been fulfilled. 2664

2. Verify that there are no contraindications to the D XA scans. Pregnant patients or patients 2665 likely to be pregnant should not have a DXA scan. It is also not recommended to scan 2666 patients whose weight exceeds the weight limit of t he densitometer as the results may not 2667 be accurate and the densitometer table may be damag ed. 2668

3. Verify that there are no artifacts. Patients who h ave a prosthetic hip or orthopedic device in 2669 the lumbar vertebrae should not have this part of t he body scanned. It is also recommended 2670 not to scan patients who have taken calcium supplem ents the day of the scan as the calcium 2671 tablet may be in the path of the X-rays and artific ially elevate the mineral content of the 2672 area scanned. Similarly patients who have undergon e radiological contrast studies on the 2673

abdomen should not be scanned until the contrast ma terial is no longer in the patient’s 2674 body. Patients should not have metallic objects on the parts scanned, including navel rings 2675 which interfere with the absorption of radiation. Other common artifacts include zippers, 2676

buttons and wallets. 2677

4. Enter and verify the accuracy of all the relevant p atient demographic information, such as 2678 the age, race, gender, weight and height. Any erro neous information will invalidate the 2679 subsequent calculation of the T- and Z-scores and h ence the validity of the scan. 2680

5. Position the patient according to the criteria set by the manufacturer. If it is not possible to 2681 position the patient as per the recommendations bec ause the patient is unable to be placed 2682 in that position because of pain or limitation of m ovement, the technologist should make a 2683

note to that effect. 2684

6. Note the scan mode (e.g., fan beam or pencil beam) and the type of leg block used. 2685

2686 During the DXA scan: 2687

1. The patient must refrain from moving. 2688

2. The technologist should: 2689

a. Ascertain that the patient’s positioning is good. If the patient positioning is not as per 2690 the accepted recommendations, the subsequent analys is of the scan will not be valid. 2691

b. Ascertain that there are no artifacts. 2692

c. Ascertain that all the regions of interest are clea rly visualized. 2693

d. Stop the DXA scan and restart it if positioning is not adequate, if there are artifacts, or if 2694 the regions of interest are not clearly visualized. 2695

2696 Analysis of the DXA scan: 2697

1. Before the analysis, the technologist needs to asce rtain that: 269857

a. The patient’s demographics are correctly noted. 2699

b. The patient’s positioning is good. 2700

c. There are no artifacts. 2701

d. The various regions of interest are clearly visuali zed. 2702

2. During the analysis, the technologist will follow t he manufacturer’s recommended 2703 procedure to identify the various regions of intere st. 2704

2705 After the analysis the technologist will print out the results of the exam that would have been 2706 configured according to parameters set by the facil ity where the scans are done. 2707

2708 Reporting the DXA scan results: 2709

1. Reports are automatically generated by the equipmen t, and should be modified to meet the 2710 needs of the facility where the scans are done. Ot her information also may be added such 2711 as risk factors for osteoporosis and fracture risk assessment FRAX scores for hips and other 2712 major fracture sites. FRAX is the World Health Org anization’s (WHO’s) Fracture 2713 Assessment Tool, a computer program used to estimat e the probability of the patient 2714 sustaining a hip or other major osteoporotic fractu re in the following ten years (WHO 2004; 2715 WHO 2012). Various models of reporting are also av ailable from the International Society 2716 of Clinical Densitometry. These may include inform ation about recommended diagnostic 2717 tests and treatment options. It is important howev er, to tailor the reports to the needs of the 2718 referring physicians. 2719

2. Various report styles exist. The ones preferred by the facility and which satisfy the needs 2720 of the referring physician should be used. Structu red reports should be used if electronic 2721 records are maintained by the facility. 2722

272358

DENTAL 2724

2725 Diagnostic imaging is an integral part of dentistry . Dental radiographs are estimated to 2726 contribute approximately one percent (0.006 mSv) of the total population’s effective dose. The 2727 daily background effective dose to a member of the U.S. general population is estimated to be 2728 3.0 mSv/365 = 0.008 mSv/day (NCRP 2009). As of 201 2, there is no scientific or epidemiologic 2729 evidence to suggest that the effective dose to the U.S. population from dental diagnostic 2730 radiographic procedures estimated to be in the rang e of 0.006 mSv carries significant potential 2731 biological risk either at the population level, or individual level. 2732

2733 The dental health-care worker’s goal is to keep rad iation exposures to the minimum necessary to 2734 meet diagnostic requirements. In 2003, the NCRP up dated its recommendations on radiation 2735 protection in dentistry (NCRP 2003). The Centers f or Disease Control and Prevention published 2736

its Guidelines for Infection Control in Dental Heal th-Care Settings in 2003, and the U.S. Food 2737 and Drug Administration along with the American Den tal Association updated selection criteria 2738 for dental radiographs in 2004 (ADA FDA 2004; CDC 2 003). In 2006, the American Dental 2739 Association published its practice recommendation f or the use of dental radiographs . All of 2740 these recommendations were considered when developi ng the following guidelines. 2741

2742 Equipment 2743

2744 It is strongly recommended that dental x-ray machin e be capable of being operated in at least the 2745 60-90 kVp range, with the x-ray beam filtration con sistent with the FDA requirements ((FDA 2746 2012f) Table 1). It is also strongly recommended t hat the equipment be collimated with a lead2747 lined 40 cm (16 in) beam indicating device (BID) ( NCRP 2003), which results in less beam 2748 divergence and less volume of patient’s tissue irr adiated per exposure. Utilization of rectangular 2749 collimation is recommended for intra-oral technique s. This further restricts the beam to 2750 approximately the size of the film/imaging receptor being used (Gibbs 2000; NCRP 2003). Use 2751 of rectangular collimation reduces the exposed area to approximately 48% compared with round 2752 collimation. This improves image quality by reduci ng scatter, resulting in a radiograph with 2753

better resolution and better contrast. 2754

2755 The dental health professional (dentist or dental h ygienist) has a variety of image receptors to 2756 select from that include conventional film, along w ith evolving digital technology which include 2757 photostimulable imaging plates and digital imaging sensors. Although digital radiography offers 2758 a potential for significant dose reduction, the num ber of retakes (commonly due to poor 2759 positioning of the bulky sensors with encumbering w ire) may result in actual increased dose for 2760 the patient unless care is given to providing prope r training and the use of image receptor 2761 positioning devices. Furthermore, due to the small er active area of some sensors, more than one 2762 exposure may be required to cover the anatomical ar ea imaged using a single conventional film. 2763 Therefore, it is recommended that an image receptor positioning device be used with sensors, 2764 that specific and ongoing training be given to orie nt operators on ways to eliminate the need for 2765 retakes, and that technique charts provided by manu facturers be reviewed for proper sensor 2766 placement. 2767

276859

In clinics or field use environments where film is still used, the fastest appropriate film should be 2769 used. For periapical and bite-wing radiographs, on ly films of American National Standard 2770 Institute Speed Group “F” or faster are recommended (NCRP 2003). Since there are minimal 2771 diagnostic differences between the various intraora l films available in 2012, the use of faster 2772 films (E- or F-speed) is preferred because they red uce the radiation dose by more than 50% when 2773 compared with D-speed film. 2774

2775 When panoramic and other extraoral projections are taken, it is recommended that high speed 2776 films be matched to their rare earth intensifying s creens. The higher speed of the rare earth 2777 screen-film combinations (400 or higher system spee d) are twice as fast as conventional calcium 2778 tungstate screen-film combinations with equivalent diagnostic value at 1/2 to 1/4 the dose to the 2779 patient (Miles et al. 1989). 2780

2781 It is imperative that the operator’s manual for all imaging acquisition hardware is readily 2782 available to the user, and that the equipment is op erated and maintained following the 2783 manufacturer’s instructions, including any appropri ate adjustments for optimizing dose and 2784 image quality. 2785

2786 Leaded aprons were recommended for dentistry when d ental x-ray equipment was poorly 2787 collimated, unfiltered, and films were much slower than those available in 2012. Given the 2788 advent of good collimation, filtration, direct curr ent x-ray machines, faster film speeds, and 2789 digital sensors, gonadal and effective doses result ing from scatter radiation are extremely low 2790 and are not significantly reduced by the use of the leaded aprons. According to NCRP Report 2791 No. 145 , technological advancements have eliminate d the requirement for lead aprons on 2792 patients when all of the following recommendations are followed: a 60-80 kVp intraoral 2793 exposure unit is used, the source-to-image receptor distance for intraoral radiography is between 2794 20-40 cm, a rectangular collimator is used for intr aoral radiographs, and a minimum of E-speed 2795 equivalent exposure film/sensors is used. It is no t unreasonable to have aprons available for 2796 patients who request their use (NCRP 2003). 2797

2798 The thyroid gland is among the most sensitive organ s to radiation-induced tumors, especially in 2799 children. NCRP Report No. 145 states that, “thyroid shielding shall be provided for children, and 2800 should be provided for adults, when it will not int erfere with the examination” (NCRP 2003). 2801 These recommendations may be relaxed in the cases w here anatomy or the inability of the 2802 patient to cooperate makes beam-receptor alignment awkward. The positive projection-angle of 2803 the panoramic x-ray beam of +4 o to +7 o essentially eliminates thyroid dose. 2804

2805 Protective aprons and thyroid shields should be hung or laid flat and never folded, and 2806

manufacturer’s instructions should be followed. Al l protective shields should be evaluated for 2807 damage (e.g., tears, folds, and cracks) at least an nually using visual and manual inspection 2808 (Miller et al. 2010b). If a defect in the attenuat ing material is suspected, radiographic or 2809 fluoroscopic inspection may be performed as an alte rnative to immediately removing the item 2810 from service. Consideration should be given to min imizing the radiation exposure of inspectors 2811 by minimizing unnecessary fluoroscopy. 2812

281360

As of 2012, hand-held, battery-powered x-ray system s are available for intra-oral radiographic 2814 imaging. The hand-held exposure device is activate d by a trigger on the handle of the device. 2815 Device operation, at first glance, poses several co ncerns, which appear inconsistent with 2816 previously established dental radiological protecti on guidelines. These concerns include: (1) the 2817 x-ray tube assembly is hand-held by the operator ra ther than wall mounted, (2) the trigger for x2818 ray exposure is on the hand-held device and not rem otely located away from the source of 2819 radiation, and (3) the operator does not stand behi nd a barrier. However, dosimetry studies 2820 indicate that these hand-held devices present no gr eater radiation risk than standard dental 2821 radiographic units to the patient or the operator ( Goren et al. 2008; Masih et al. 2006; Witzel 2822 2008). No additional radiation protection precauti ons are needed when the device is used 2823 according to the manufacturer’s instructions. Thes e include: (1) holding the device at mid-torso 2824 height, (2) orienting the shielding ring properly w ith respect to the operator, and (3) keeping the 2825 cone as close to the patient’s face as practical. If the hand-held device is operated without the 2826 ring shield in place, it is recommended that the op erator wear a lead apron. 2827

2828 All operators of hand-held units should be instruct ed on their proper storage. Due to the portable 2829 nature of these devices, they should be secured pro perly when not in use to prevent accidental 2830 damage, theft or operation by an unauthorized user. Hand held units should be stored in locked 2831 cabinets, locked storage rooms or locked work areas when not under the direct supervision of an 2832

individual authorized to use them. Units with user -removable batteries should be stored with the 2833 batteries removed. Records listing the names of ap proved individuals who are granted access 2834 and use privileges should be prepared and kept curr ent. 2835

2836 Testing and Quality Assurance 2837

2838 Quality assurance refers to those steps that are ta ken to make sure that a dental facility or 2839 imaging facility consistently produces images that are adequate for the purpose with optimal 2840 patient and minimal operator exposure. Quality ass urance may be divided into two major 2841 categories: quality administration and quality cont rol. Quality administration refers to the 2842 management aspect of a quality assurance program. It includes those organizational steps taken 2843 to make sure that testing techniques are properly p erformed and that the results of tests are used 2844 to effectively maintain a consistently high level o f image quality. An effective program includes 2845 assigning personnel to determine optimum testing fr equency of the imaging devices, evaluate 2846 test results, schedule corrective action, provide t raining, and perform ongoing evaluation and 2847 revision of the quality assurance program. 2848

2849 Quality control comprises the procedures used for t he routine physical testing of the primary 2850 components of the dental imaging chain from the x-r ay machine, through processing, to the 2851 viewing of dental images. Quality control measures are listed in Table 2. Each facility, through 2852 its radiation quality control team (e.g. health phy sicist, medical physicist, biomedical 2853 maintenance personnel), needs to track maintenance and monitoring procedures. Dental clinics 2854 that use film should evaluate film processing darkr ooms and daylight loaders for light leaks and 2855 safelight performance. 2856

2857

285861

Personnel 2859

2860 As in general medical radiology, it is important to eliminate unproductive radiation exposure in 2861 dentistry; thus, privileges to order dental x-ray e xaminations should be limited to Doctors of 2862 Dental Surgery or Dental Medicine who are eligible for licensure in the United States or one of 2863 its territories or commonwealths. Exception may be granted for persons in post graduate training 2864 status under the supervision of a person meeting su ch requirements. Variances to the above 2865 qualification requirements should occur only for em ergency or life-threatening situations, such as 2866 natural disasters. Also, non-peacetime operations in the field or aboard ship could require such 2867 variances. Dental equipment operators should recei ve appropriate education and training in the 2868 areas of anatomy, physics, technique and principles of radiographic exposure, radiation 2869 protection, radiographic positioning, and image pro cessing that are relevant to dental imaging. 2870 Proficiency can be demonstrated by satisfying exist ing state certification programs for dental 2871 auxiliaries. Also, proficiency can be improved by r eviewing dental radiology practice 2872

recommendations from the American Dental Associatio n. 2873

2874 Operators of dental x-ray equipment may be exposed to primary radiation in the useful beam, 2875 leakage radiation from the tube housing, and scatte red radiation. Operator protection measures 2876 are required to minimize their occupational exposur e. There are three basic methods to reduce 2877 the occupational dose from x-rays: position, distan ce, and shielding. The most effective way of 2878 reducing operator exposure to primary radiation is to enforce strict application of the position 2879

and distance rule (i.e., the operator should stand at least 2 m (6 ft ) away from the tube head of 2880 the dental x-ray generator). If the operator canno t stand at least this far from the patient during 2881 the exposure, he or she should stand behind an appr opriate barrier or outside the operatory 2882 behind a wall. In clinics or field situations, whe re the operator is required to be in the immediate 2883 exposure area, the operator should be positioned at the location of minimum exposure. This 2884 location, also known as the safe quadrant, is at an angle between 90 and 135 o to the primary 2885 beam. Dental personnel should not hold image recep tors in patients’ mouths. If a patient has to 2886 be restrained during exposure, a relative or friend of the patient should do so. The relative or 2887 friend may be provided a lead apron and latex glove s if the image receptor is to be held in the 2888 mouth so they have protection during exposure. 2889

2890 In panoramic imaging, scattered radiation is typica lly low due to the narrow beam of radiation 2891 and the shielding incorporated into the cassette ca rrier. With a typical workload, operators can 2892 produce panoramic images without the use of shieldi ng as long as they are at least 2 meters (6 2893 feet) from the unit. An appropriate shield should be used if this distance cannot be maintained. 2894

2895 Structural shielding criteria are provided by NCRP (NCRP 2003). Only a qualified individual 2896 (preferably a qualified physicist) can determine ho w much shielding is needed for a given 2897 situation. The walls of the dental x-ray operatory must provide sufficient attenuation to limit the 2898 exposure of other individuals to permissible levels . Usually, it is not necessary to line the walls 2899 with lead to meet this requirement when intraoral o r panoramic equipment is used. A wall 2900 constructed of gypsum wall board (drywall) has been determined to be sufficient for use of this 2901 equipment in the average dental office (MacDonald e t al. 1983). 2902

290362

Any individual who is likely to exceed a designated fraction of the regulatory dose limit shall be 2904 enrolled in a radiation monitoring program (OSHA 20 12; USNRC 2012c). Historically, dental 2905 radiation workers have not approached these limits and have not required dosimetry when good 2906 radiation practices have been used. To determine i f dosimeters are required, evaluations of 2907 occupational dose should be conducted by a qualifie d physicist when a program is initiated, 2908 facilities are significantly modified, or equipment or processes change. The evaluation may 2909 consist, for example, of monitoring personnel for a period of time or assessing the radiation field 2910 around the equipment. With regard to workers who h ave declared their pregnancy, NCRP 2911 Report No. 145 states that “Personal dosimeters sha ll be provided for known pregnant 2912 occupationally-exposed personnel” (NCRP 2003). 2913

2914

Procedures 2915

2916 Justification applies to imaging in dentistry. The number of images obtained should be the 2917 minimum necessary to obtain essential diagnostic in formation. Dental radiographs should be 2918 prescribed only following an evaluation of the pati ent’s needs that includes a health history 2919 review, a clinical dental history assessment, a cli nical examination and an evaluation of 2920 susceptibility to dental diseases. A full mouth su rvey or panoramic radiograph of the teeth and 2921 jaw structure may be justified for forensic purpose s for military personnel. Postoperative 2922 radiographs should be taken only when there is clin ical indication and not as verification for 2923 third-party payment plans. This is consistent with the recommendations of the Food and Drug 2924

Administration and the American Dental Association (ADA FDA 2004; NCRP 1990). In cases 2925 where emerging new dental imaging technologies are used by physicians for non-dental 2926 evaluations, these physicians should request these studies through their medical imaging ordering 2927 procedures as determined by their local facility. 2928

2929 Optimization also applies to imaging in dentistry. In order to achieve lower exposures, the 2930 operator’s manual should be readily available to th e user, and the equipment should be operated 2931 following the manufacturer’s instructions, includin g any appropriate adjustments for optimizing 2932 dose and ensuring adequate image quality. The x-ra y machine should be operated at the highest 2933 kilovoltage (kVp) adequate for diagnosis. An image receptor holding device should be used for 2934 proper film, photostimulable phosphor (PSP) plates, or sensor positioning whenever possible. 2935 Technique charts provided by manufacturers should b e reviewed for proper image receptor 2936 placement. Protocols may be relaxed in the cases w here anatomy or the inability of the patient to 2937 cooperate makes beam-receptor alignment awkward. 2938

2939 Cone beam computed tomography (CBCT) is used for de ntal implant planning, orthodontics, 2940 surgical assessment of pathology, pre- and postoper ative assessment of craniofacial fractures, 2941 and temporomandibular joint assessment. CBCT provi des high-resolution computed 2942 tomographic images with short scanning times (appro ximately 20 seconds) and high geometric 2943 accuracy (actual size of item imaged without distor tion) (Scarfe et al. 2006). The major 2944 advantage of CBCT over multi-row detector computed tomography systems (MDCT) is the 2945

lower radiation dose . CBCT scanners utilize a nar row, collimated cone beam of radiation that 2946

scans both the maxilla and mandible at one time. T he effective dose of a CBCT examination is 2947 approximately 7 times greater than a panoramic imag e but only 2-5% of a conventional CT of 2948 the same region (Scarfe et al. 2006). Given these low radiation doses, the same radiation 294963

protection guidelines recommended for conventional dental imaging should be implemented for 2950

CBCT. 2951

295264

VETERINARY 2953

2954 Diagnostic radiology is an essential part of presen t-day veterinary practice. The typical imaging 2955 workload in a veterinary practice is low on the ave rage; however, certain practices unique to 2956 veterinary radiology can expose the staff at a grea ter rate than typical operators. In veterinary 2957 medicine, the possibility that anyone may be expose d to enough radiation to create deterministic 2958 effect is extremely remote. 2959

2960 There are two main aspects of the problem to be con sidered. First, personnel working with x-ray 2961 imaging equipment should be protected from excessive exposure to radiation d uring their work. 2962 Secondly, personnel in the vicinity of veterinary r adiology facilities and the general public 2963 require adequate protection (NCRP 2004b; OSHA 2012; USNRC 2012c). 2964

2965 Equipment 2966

2967 The recommendations pertaining to the use of medica l radiographic equipment and shielding 2968 requirements for humans apply to the use of similar equipment in veterinary medicine. The 2969 following points are highlighted for veterinary app lications: 2970

2971

1. In a fixed facility, the floors, walls, ceilings an d doors should be built with materials 2972 providing adequate radiation protection to workers. 2973

2. The shielding should be constructed to form an unbr oken barrier. 2974

3. In a fixed facility, a control booth should be prov ided for the protection of the operator. 2975 Mobile protective barriers are not considered adequ ate as a control booth except for 2976 facilities requiring no shielding at 1 meter from s ource, or where 1/20 of permissible dose 2977 equivalent limits are not likely to be exceeded at 1 meter. 2978

4. The control booth should be located, whenever possi ble, such that the radiation has to be 2979 scattered at least twice before entering the booth. In facilities where the radiation beam 2980 may be directed toward the booth, the booth becomes a primary barrier and should be 2981 shielded accordingly. 2982

5. The control booth should be positioned so that duri ng an irradiation no one can enter the 2983 radiographic room without the knowledge of the oper ator. 2984

6. Required warning signs should be posted on all entr ance doors of each x-ray imaging room. 2985

7. Mobile x-ray equipment used routinely in one locati on is considered to be a fixed 2986 installation, and the facility should be shielded a ccordingly. 2987

8. Protective aprons, gloves and thyroid shields used for veterinary x-ray examinations should 2988 provide attenuation equivalent to at least 0.5 mm o f lead-equivalence at x-ray tube voltages 2989 of up to 150 kVp. Protection should be provided th roughout the glove, including fingers 2990 and wrist. Further discussion is provided in the se ction on RADIATION SAFETY 2991

PROCEDURES FOR FLUOROSCOPY. 2992

2993

2994 An addition to the diagnostic veterinary imaging in ventory as of 2012 is hand-held, battery2995 powered x-ray systems which have been developed for radiographic imaging. The hand-held 2996 exposure device is activated by a trigger in the ha ndle of the device by the operator. This 2997 technology, at first glance, poses several concerns , which appear inconsistent with previously 299865

established radiological protection guidelines. Th e first concern is that the x-ray tube assembly 2999 is hand-held by the operator rather than wall mount ed. The second concern is that the trigger for 3000 x-ray exposure is within the hand-held device and n ot remotely located away from the source of 3001 radiation. The final concern is that the operator does not stand behind a barrier. These concerns 3002 arise from previous guidelines that were establishe d to: 1) protect the operator from possible 3003 radiation leakage from the housing of the device; 2 ) protect the operator from backscatter from 3004 the patient; and 3) protect the patient from excess ive radiation or repeat exposures when 3005 inadequate image quality results from movement of t he hand-held x-ray generator. 3006

3007 For additional information, see the veterinary sect ion below on SPECIAL PROCEDURES FOR 3008

PORTABLE HAND-HELD SYSTEMS. 3009

3010 Testing and Quality Assurance 3011

3012 Since veterinary equipment is generally identical t o medical equipment all the quality assurance 3013 tasks associated with medical equipment can be appl ied to veterinary equipment; however, based 3014 on the typical workload a reduced quality assurance program is probably warranted in most 3015 cases. A typical testing and QA program would cons ist of at least the following: 3016

1. It is essential that a radiation safety survey be c ompleted on all new veterinary x-ray 3017 equipment by or under the direction of a qualified expert. As stated in NCRP Report No. 3018 148, “Resurveys shall be made following replacement of irradiation equipment, or 3019 modifications that could change the radiation sourc e, whenever the workload increases 3020 significantly, or if other operating conditions are modified that could affect the radiation 3021 dose in occupied areas. Resurveys are required aft er the installation of supplementary 3022 shielding to determine the adequacy of the modifica tion” (NCRP 2004b). 3023

2. Prior to the first use of a mobile fluoroscope, a r adiation exposure survey should be done 3024 with the x-ray beam and maximum operating potential and with an appropriate test 3025 phantom in place to determine the perimeter of the area within which individuals without 3026 radiation protection apparel should not be present (NCRP 2004b). 3027

3. Reduce radiation exposure to the animal patient, op erator, and members of the public by 3028 minimizing the need for repeat exposures because of inadequate image quality (NCRP 3029 2004b). 3030

4. For film-based systems, a sensitometry and densitom etry test should be done each day the 3031 system is used in order to ensure consistent operat ion. A step wedge test may be used as a 3032 substitute for the standard sensitometry and densit ometry test. 3033

5. Darkroom fog or darkroom integrity should be evalua ted biannually. This may be 3034 especially relevant if the darkroom is not a single use room. 3035

6. It is strongly recommended that lead personnel prot ective equipment (e.g., aprons, gloves, 3036 thyroid collars) be evaluated at least annually for lead protection integrity using visual and 3037 manual inspection (Miller et al. 2010b; NCRP 2010). If a defect in the attenuating material 3038 is suspected, radiographic or fluoroscopic inspecti on may be performed as an alternative to 3039 immediately removing the item from service. Consid eration should be given to minimizing 3040 the radiation exposure of inspectors by minimizing unnecessary fluoroscopy. 3041

3042

304366

Personnel 3044

3045 Veterinary x-ray equipment operators, similar to me dical x-ray equipment operators, should 3046 receive appropriate education and training in the a reas of anatomy, physics, technique and 3047 principles of radiographic exposure, radiation safe ty, radiographic positioning, and image 3048 processing that are relevant to veterinary imaging. Only personnel with specific, appropriate 3049 training should be permitted to operate x-ray equip ment. It is strongly recommended that the 3050 veterinary medical application of x-ray equipment b e performed only by or under the general 3051 supervision of a veterinarian properly trained and credentialed to operate such equipment. 3052 Individuals who routinely use veterinary radiologic equipment need a basic understanding of the 3053 following: 3054

3055

1. animal positioning techniques to allow for minimal radiation exposure for employees; 3056

2. basic principles and concepts of radiation in gener al and x-radiation in particular; 3057

3. component parts/workings of the x-ray machine and t he production of x-rays; 3058

4. factors affecting the quality of the x-ray beam and the radiographic image; 3059

5. effects of ionizing radiation on living tissues; 3060

6. radiation bioeffects, health, and safety; 3061

7. radiation protection procedures for the operator an d the patient; 3062

8. selection of appropriate imaging surveys, image rec eptor types, duplicating, and record 3063 keeping; 3064

9. technique of proper image processing, handling, and record keeping; 3065

10. viewing techniques and principles of interpretation ; 3066

11. digital imaging and alternate imaging modalities; 3067

12. appearances of normal radiographic landmarks, artif acts, and shadows; and 3068

13. requirements for monitoring and documenting staff o ccupational radiation exposure. 3069

3070

Procedures 3071

3072 The procedures pertaining to the use of veterinary radiography are generally equivalent to 3073 procedures for medical (human) radiography. The fo llowing recommendations will minimize 3074 the dose to veterinary facility staff and clients f rom veterinary diagnostic radiographic 3075 procedures. All suggestions will secondarily minim ize the dose to the radiation operator and 3076 consequently, the results may be considered as a do uble benefit to the patient and the worker. 3077 The guidelines and procedures outlined in this sect ion are primarily directed toward occupational 3078 health protection. Adherence to these guidelines w ill also provide protection to visitors and 3079 other individuals in the vicinity of an x-ray facil ity. However, the safe work practices and 3080 procedures for using various types of x-ray equipme nt should be regarded as a minimum to be 3081 augmented with additional requirements, when warran ted, to cover special circumstances in 3082 particular facilities. To achieve optimum safety, operators should make every reasonable effort 3083 to keep exposures to themselves and to other person nel as low as reasonably achievable. 3084

3085

Veterinary clinic setup 3086

3087

1. An x-ray room should be used for only one x-ray pro cedure at a time. 308867

2. All entrance doors to an x-ray room should be kept closed while a radiographic procedure is 3089 being performed. 3090

3. Where a control booth or protective barrier is avai lable, it is strongly recommended that 3091 operators remain inside or behind when making an ir radiation. If a control booth or 3092 protective screen is not available, the operator sh ould always wear protective clothing. 3093

4. When film screen imaging is used, the fastest combi nation of films and intensifying screens 3094 consistent with diagnostically acceptable results a nd within the capability of the equipment 3095

should be used. 3096

5. When digital x-ray imaging is used, procedures shou ld be established to prevent 3097 excessively high doses, also known as dose creep, a s addressed in the radiography section 3098

of this document. 3099

3100 Personal protective equipment 3101

3102

1. Personnel should use protective devices, as appropr iate. 3103

2. Protective aprons, gloves and thyroid shields shoul d be hung or laid flat and never folded, 3104

and manufacturer’s instructions should be followed. 3105

3. Armored gloves (welding gloves) should be used to r estrain fractious animals. Since lead3106 lined gloves will not protect against bites that co uld puncture the lead, the radiation 3107 protection provided by the garment may be compromis ed (NCRP 2004b). 3108

3109

Animal restraint 3110

3111

1. If necessary, the animal should be sedated or holdi ng devices used during radiography. 3112 However, if this is not possible and a person must restrain the animal, that person should 3113 wear appropriate radiation protective equipment (ap rons, gloves, etc.) and avoid direct 3114 irradiation by the primary x-ray beam. No person s hould routinely hold animal patients 3115 during x-ray examinations (NCRP 2004b). 3116

2. Individuals under the age of 18 and pregnant or pot entially pregnant women should not be 3117 permitted to hold animals during radiography. 3118

3119 Use of x-ray equipment 3120

3121

1. X-ray equipment should be operated only by or under the direct supervision of qualified 3122

individuals. 3123

2. X-ray machines that are energized and ready to prod uce radiation should be supervised. 3124

3. The x-ray room should contain only those persons wh ose presence is essential when a 3125 radiological procedure is carried out. 3126

4. The radiation beam should always be directed toward adequately shielded or unoccupied 3127

areas. 3128

5. The radiation beam and scattered radiation should b e attenuated as closely as possible to the 3129

source. 3130

6. Personnel should keep as far away from the x-ray be am as is practicable at all times (2 m). 3131 Exposure of personnel to the x-ray beam should neve r be allowed unless the beam is 3132 adequately attenuated by the animal and by protecti ve clothing or barriers. 3133

7. A hand-held radiographic cassette or image receptor should not be used. 313468

8. For table-top radiography when the sides of the tab le are not shielded, a sheet of lead at 3135 least 1 mm in thickness and slightly larger than th e maximum beam size should be placed 3136 immediately beneath the cassette or film. 3137

9. Veterinarians should not allow veterinary diagnosti c radiation devices under their control to 3138 be used on human beings (NCRP 2004b). 3139

10. Technique charts should be developed for all animal types that are routinely radiographed. 3140

3141 Personal dosimetry 3142

3143

1. The workload in a typical veterinary clinic may not be sufficient to require the issuance of 3144 personal dosimetry; however, a qualified expert sho uld be consulted for a clinic’s particular 3145

situation. 3146

2. Personal dosimetry should be worn in a manner that complies with regulatory requirements 3147

and ensures that radiation doses can be determined accurately. See the section on 3148

PERSONNEL AND AREA MONITORING. 3149

3. Occupational radiation dose limits in veterinary an d human medical practice should be the 3150

same. See the section on PERSONNEL AND AREA MONITO RING. 3151

3152 Special procedures for portable hand-held systems 3153

3154

1. Portable hand-held x-ray systems should be used as outlined in the instructions that come 3155 with the unit. Exposures using this unit should be made only when the area adjacent to the 3156

clinical area is free of all individuals not direct ly involved in the imaging procedure. When 3157 standard radiology protocols are utilized according to manufacturer instructions, with the 3158 ring shield in place, there is no indication for ad ditional radiation protection 3159

recommendations. 3160

3161

2. Portable hand-held x-ray systems use essentially th e same amount of radiation as 3162 traditional wall mounted x-ray units since the amou nt of radiation needed to generate an 3163 adequate image is determined by the image receptor, not by the x-ray device. Radiation 3164 safety criteria for operators of the hand-held devi ce should be the same as mentioned 3165 earlier for conventional exposure systems. 3166

3167

3. All operators of these units should be instructed o n its proper storage. Due to the portable 3168 nature of the hand-held device, it should be secure d properly when not in use to prevent 3169 accidental damage, theft or operation by an unautho rized user. Hand held units should be 3170 stored in locked cabinets, locked storage rooms or locked work areas when not under the 3171 direct supervision of an individual authorized to u se them. Units with user-removable 3172

batteries should be stored with the batteries remov ed. Records listing the names of 3173 approved individuals that are granted access and us e privileges should be prepared and kept 3174 current (quarterly review). 3175

317669 MEDICAL IMAGING INFORMATICS 3177

3178 Digital information systems are used for the orderi ng, scheduling, tracking, processing, storage, 3179 transmission, and viewing of imaging studies and pr oviding the reports of study interpretations. 3180 These systems should be used to the greatest extent possible. They include picture archiving and 3181 communication systems (PACSs), teleradiology system s, radiology information systems, 3182 hospital information systems, and the Electronic He alth Record (Congress 2007). For efficiency 3183 of workflow, these systems do not operate independe ntly, but instead are connected to the 3184 imaging devices and each other by computer networks and exchange information in accordance 3185 with standards such as TCP/IP (Transmission Control Protocol/Internet Protocol, or the Internet 3186 protocol suite), DICOM, HL7, and IHE. These inform ation systems are complex and will not be 3187 discussed in detail in this report. However, there are certain aspects of these systems that 3188 indirectly can affect the radiation doses to patien ts from imaging studies. Proper planning, 3189 design, management, and use of these systems can he lp avoid performing unnecessary or 3190 inappropriate studies and repeat studies. These sy stems can also help in monitoring doses to 3191 patients and image receptors and monitoring retakes ; the information from this monitoring can 3192 help in optimizing doses from imaging procedures. 3193

3194 These information systems can help avoid the orderi ng of unnecessary or inappropriate imaging 3195 studies. At the time that a Referring Medical Prac titioner places the order for an imaging study, 3196 the system can provide decision support regarding t he appropriateness of the study for the 3197 particular patient and notification of alternatives that may impart less or no radiation. These 3198 information systems can also notify the Referring M edical Practitioner of previously acquired 3199 studies that may render an additional imaging study unnecessary. 3200

3201 The inability to retrieve an imaging study can crea te the need for a repeat study. These digital 3202 information systems and procedures for their use sh ould be designed to protect against data loss. 3203 Such measures should include administrative, physic al, and technical safeguards, including 3204 storing information on stable media, ensuring the s torage location is secure from natural and 3205 human threats, ensuring the stored information is s ecure from deliberate or accidental erasure or 3206 modification, storing duplicate backup copies of th e information on media in a remote location 3207 or locations, and precautions against loss of infor mation from media wear and aging and media 3208 obsolescence. Additionally, the facility should ha ve a disaster plan in place to guide operations 3209 when the network is inoperable or power outage affe cts operation of the PACS system. It is the 3210 responsibility of the institution to meet the recor ds retention, security, privacy, and retrieval 3211 requirements of its agency and other Federal requir ements (e.g., HIPAA and associated Federal 3212 regulations) (ACR 2007c; ACR 2009a; DHHS 2012b), an d to address the aforementioned issues. 3213

3214 These systems also provide an important quality ass urance function. They should facilitate 3215 monitoring of patient dose indices, the doses to ra diographic image receptors, and the 3216 number of retakes and inadequate images. This requ ires both capture and storage of this 3217 information and appropriate software tools for data analysis and display. Equipment 3218 manufacturers should be encouraged to work with pro fessional societies and standards 3219 organizations to develop and implement standardized dose reporting systems. These 3220 systems should provide an estimate of patient radia tion dose that is accurate for the 3221 individual, available in real time to the operator, and documented for the individual 322270

patient. These systems should also be capable of t ransmitting de-identified patient 3223 radiation dose data to a central dose registry. To this end, Federal facilities should give 3224 preference to equipment with these standardized dos e reporting systems when making 3225 purchasing decisions. 3226

322771 SUMMARY AND RECOMMENDATIONS FOR FACILITY ACTION 3228

3229

GENERAL 3230

3231

1. Each facility should establish a formal mechanism w hereby Referring Medical Practitioners 3232

have sources of information available at the time o f ordering regarding appropriate 3233 diagnostic imaging methods to answer the clinical q uestion and to optimize ionizing 3234 radiation dose to the patient. These may include d ecision support software or 3235 appropriateness criteria. A mechanism for consulta tion with Radiological Medical 3236

Practitioners should also be made available. 3237

2. The Universal Protocol should always be followed to ensure the right patient gets the right 3238 procedure. 3239

3. Physicians and staff should always strive to limit patient irradiation to that necessary to 3240 perform the procedure. 3241

4. Facilities involved in health care delivery should ensure that operators of medical imaging 3242 equipment that use x-rays: 1) are adequately traine d to produce acceptable quality images, 3243 2) know how to produce these images with appropriat e patient doses, and 3) periodically 3244 demonstrate continuing competence. 3245

5. Facilities should ensure that the operator’s manual is readily available to the user, and the 3246 equipment is operated following the manufacturer’s instructions, including any appropriate 3247 adjustments for optimizing dose and ensuring adequa te image quality. 3248

6. Facilities should establish a formal mechanism wher eby Radiological Medical Practitioners 3249 are available to consult with Referring Medical Pra ctitioners regarding the optimal 3250 diagnostic imaging method to answer the clinical qu estion while minimizing ionizing 3251 radiation dose to the patient. 3252

7. Facilities should use equipment that provides relev ant patient dose information. This 3253 equipment should allow the facility to program in d ose alerts to inform operators if selected 3254 operating parameters might produce a radiation dose exceeding that recommended by the 3255 facility. 3256

8. Facilities should use the dose information from ind ividual patient imaging procedures that 3257 is provided by imaging equipment as part of the qua lity assurance program for identifying 3258 opportunities to reduce dose. . 3259

9. Facilities should use reference levels as a quality improvement tool by collecting and 3260 assessing radiation dose data. Each facility shoul d also submit its radiation dose data to a 3261 national registry, if and when such a registry is a vailable. 3262

10. Facilities should be aware of upgrades to software and hardware of x-ray imaging systems 3263 that enhance safety. These should be evaluated and considered for implementation. 3264

11. Facilities should assess the radiation exposure of workers and provide periodic feedback to 3265 them. In addition, each worker who is expected to receive more than 10% of the applicable 3266 dose limit should be required to wear one or more d osimeters. 3267

3268

BONE DENSITOMETRY 3269

3270

1. Facilities should establish a range of acceptable p recision performance and ensure each 3271 technologist is trained and meets this standard. 327272

2. The facility should ensure that patients imaged for precision and cross-calibration studies 3273 should be representative of the facility’s patient population 3274

3. Facilities should ensure that practitioners who int erpret bone densitometry results are 3275 knowldegable in this field and not rely solely on a report produced by the equipment.. 3276

3277

CHILDREN AND PREGNANT WOMEN 3278

3279

1. Facilities should ensure that when a monitored radi ation worker declares her pregnancy she 3280 wears a dosimeter on the lower abdomen, underneath the apron at the level of the fetus. 3281 The dosimeter should be exchanged monthly. She sho uld be issued this dosimeter unless 3282 such a dosimeter is already being worn. 3283

2. Children are more radiosensitive than adults. Faci lities should ensure that technique and 3284 imaging protocols are appropriate for the child’s s ize or weight to ensure adequate image 3285 quality and optimize radiation dose. 3286

3. In general, facilities should ensure that neither s creening nor elective x-ray examinations 3287 are performed on pregnant women. 3288

3289

DENTISTRY 3290

1. Facilities should ensure that beam indicating devic es are used with sensors, specific and 3291 ongoing training is given to orient operators on wa ys to eliminate the need for retakes, and 3292 technique charts provided by manufacturers are revi ewed periodically for proper sensor 3293 placement. 3294

2. In clinics or field use environments where film may still need to be used, the fastest and 3295 most appropriate film should be used. 3296

3. In facilities where panoramic and other extraoral p rojections are obtained using film, it is 3297 recommended that high speed film be used and spectr ally matched to its appropriate rare 3298 earth intensifying screen. 3299

4. An image receptor holding device for proper film, P SP or sensor positioning should be used 3300 whenever possible. 3301

5. Thyroid shielding shall be provided for children, a nd should be provided for adults, when it 3302 will not interfere with the examination (NCRP 2003)

. 3303

6. Dental clinics that use film should evaluate film p rocessing darkrooms and daylight loaders 3304 for light leaks and safelight performance. 3305

3306

FLUOROSCOPY 3307

1. The facility’s procedures should be written with th e understanding that fluoroscopy can 3308 deliver a significant radiation dose to the patient , even when used properly. 3309

2. The facility should ensure that every person who op erates or directs the operation of 3310 fluoroscopic equipment is trained in the safe use o f the equipment. 3311

3. When a facility purchases fluoroscopic equipment, t he additional cost of including dose3312 reduction technology is justified because the reduc tion in patient radiation dose can be 3313

considerable. 3314

4. Some types of fluoroscopic procedures have a potent ial for patient skin doses exceeding 2 3315 Gy. The facility should ensure that there are addi tional training requirements for operators 3316 and additional equipment requirements for these pro cedures. 331773

5. The facility should ensure that patient radiation d ose data, including patient skin dose data 3318 when available, are recorded in the patient’s medic al record. 3319

3320

VETERINARY 3321

3322

1. Facilities should ensure that the veterinary medica l application of x-ray equipment is 3323 performed only by or under the general supervision of a veterinarian properly trained and 3324 credentialed to operate such equipment. 3325

2. Facilities should ensure that individuals who routi nely use veterinary radiographic 3326 equipment have a basic understanding of using medic al x-rays and animal positioning 3327 techniques. 3328

3. Facilities should ensure that armored gloves (weldi ng gloves) are used to restrain fractious 3329 animals since lead-lined gloves will not protect ag ainst bites that could puncture the lead. 3330

4. Facilities should have animal sedatives and holding devices available, and ensure they are 3331 used, if necessary. 3332

5. Facilities should not allow anyone to routinely hol d animal patients during x-ray 3333

examinations. 3334

6. Facilities should not allow veterinary diagnostic r adiation devices under their control to be 3335 used on human beings. 3336

3337

INFORMATICS 3338

3339

1. Patient safety requires that infrastructure exists for collecting, storing, and analyzing patient 3340 dosimetry data. Facilities should plan for longitu dinal tracking of patient radiation doses. 3341 This planning should address the data acquisition, networking, storage, analysis, and 3342 security requirements of existing and planned futur e diagnostic devices. 3343

2. Digital information systems should be used in Feder al facilities to the greatest extent 3344 possible. 3345

3. Facilities should give preference to equipment with standardized dose reporting systems 3346 when making purchasing decisions. 3347

4. Facilities should ensure that their health professi onals use digital information systems, to 3348 help avoid the ordering of unnecessary or inappropr iate imaging studies. 3349

3350

INFORMED CONSENT 3351

3352 Federal facilities should ensure that, except in em ergency situations, informed consent is 3353 obtained from the patient or the patient’s legal re presentative and is appropriately 3354 documented prior to the initiation of any procedure that is likely to expose the patient, or 3355 fetus if the patient is pregnant, to significant ri sks and potential complications. 3356

3357

PRESCRIPTION 3358

3359 Facilities should ensure that appropriate informati on is obtained and reviewed at the time of 3360 ordering/prescribing to optimize the choice of stud y and protocol, and to optimize the dose. 3361

336274

REFERENCE LEVELS 3363

3364

1. Reference levels are dose values for a standard pha ntom or actual patient for specific 3365 procedures measured at a number of representative c linical facilities. Facilities should use 3366 reference levels as quality assurance and quality i mprovement tools. 3367

2. National reference levels that are specific for the U.S. population should continue to be 3368 developed. The on-going nationwide collection of t hese data from government and non3369 government facilities, such as by NEXT and ACR, is essential to this effort. Facilities 3370 should submit radiation dose data to a national reg istry, if and when available. 3371

3. Facilities should ensure that a representative samp ling and assessment of exposure 3372 indicators from each modality is performed at least annually, but preferably quarterly. It 3373 should be reviewed by the chief technologist. This effort should be performed under the 3374 guidance of a qualified physicist. 3375

4. If the mean radiation dose at the facility exceeds the reference level, the facility should 3376 investigate as appropriate to reduce radiation dose . If the mean radiation dose is 3377 significantly lower than the reference level, the f acility should evaluate image quality. 3378

5. If local practice at a facility results in a mean r adiation dose that is greater than the RL, the 3379 facility should investigate the equipment. If the equipment is functioning properly and 3380 within specification, operator technique and proced ure protocols should be examined. 3381

3382A-75 ACRONYMS AND ABBREVIATIONS 3383

3384 AAPM American Association of Physicists in Medicin e 3385 ACC American College of Cardiology 3386 ACCF American College of Cardiology Foundation 3387

ACGME Accreditation Council for Graduate Medical Ed ucation 3388 ACR American College of Radiology 3389 ACS American Cancer Society 3390

ADA American Dental Association 3391 AEC automatic exposure control 3392

AHA American Heart Association 3393 ALARA as low as reasonably achievable 3394

AMA American Medical Association 3395

ANSI American National Standards Institute 3396 AOA American Osteopathic Association 3397 AOBR American Osteopathic Board of Radiology 3398 ARRT American Registry of Radiologic Technologists 3399 ATSDR Agency for Toxic Substances and Disease Regis try 3400 BEIR Biological Effects of Ionizing Radiation 3401 BID beam indicating device 3402 BMD bone mineral density 3403 CBCT cone beam computed tomography (cone beam CT) 3404 CFR Code of Federal Regulations 3405 CIRSE Cardiovascular and Interventional Radiology Society of Europe 3406

cm centimeter 3407 CNMT Certified Nuclear Medicine Technologist 3408 CR computed radiography 3409 CRCPD Conference of Radiological Control Program Di rectors 3410 CT computed tomography 3411 CTDI computed tomography dose index 3412

CTDI vol volumetric CTDI 3413 DAP dose area product (units are Gy-cm 2 ) 3414

DC direct current 3415

DDM Doctor of Dental Medicine 3416 DDR Direct digital radiography 3417 DDS Doctor of Dental Surgery 3418

DEXA see DXA 3419 DHHS Department of Health and Human Services 3420 DLP dose length product 3421 DoD Department of Defense 3422 DR digital radiography 3423 DRT Diagnostic Radiologic Technologist 3424 DXA dual-energy x-ray absorptiometry (formerly DEX A) 3425

EHR Electronic Health Record 3426 EPA Environmental Protection Agency 3427 ESE entrance skin exposure 342876

ESEG entrance skin exposure guide 3429 FDA Food and Drug Administration 3430 FGI Fluoroscopically-guided interventional 3431 FGR Federal Guidance Report 3432

FOV field of view 3433 GI gastrointestinal 3434 GSD genetically significant dose 3435 Gy gray (radiation dose, equal to 100 rem). Subuni t is mGy (milligray) 3436 HRS Heart Rhythm Society 3437 ICRP International Commission on Radiological Prot ection 3438

IEC International Electrotechnical Commission 3439

IRB Institutional Review Board 3440 ISCD International Society for Clinical Densitomet ry 3441 ISCORS Interagency Steering Committee on Radiation Standards 3442 KAP kerma area product 3443 kerma kinetic energy released in matter (type of r adiation measurement in air) 3444

kV kilovolts 3445 kVp kilovolts potential (or kilovolts peak) 3446 mA milliampere 3447 mammo mammography 3448 mAs milliampere-second 3449 MDCT multi-row detector computed tomography (multi -detector CT) 3450 MQSA Mammography Quality Standards Act 3451

mrem millirem 3452

mSv millisievert 3453

NCI National Cancer Institute 3454

NCRP National Council on Radiation Protection and Measurements 3455 NEXT Nationwide Evaluation of X-ray Trends 3456

NIH National Institutes of Health 3457 OSHA Occupational Safety and Health Administration 3458 OSL optically stimulated luminescence 3459 PACS picture archiving and communication system 3460 PET positron emission tomography 3461 PSD position-sensitive x-ray detection 3462 PSP photostimulable phosphor 3463 RCIS Registered Cardiovascular Invasive Specialist s 3464 rem Traditional radiation unit for equivalent dose (product of absorbed dose [rad] and 3465 radiation weighting factor). Subunit is mrem (milli rem) or μrem (microrem) 3466 RSO Radiation Safety Officer 3467 RT(N) Radiological Technologist Nuclear qualificat ion 3468 SCAI Society for Cardiac Angiography and Intervent ion 3469 SPECT single particle emission computed tomography 3470 SIR Society of Interventional Radiology 3471

SSD source-to-skin distance 3472 Sv sievert (SI radiation unit for equivalent dose o r effective dose). Subunit is mSv 3473 (millisievert) or μSv (microsievert) 347477

TLD thermoluminescent dosimeter 3475

USPSTF United States Preventive Services Task Force 3476 USN United States Navy 3477 VA US Department of Veterans Affairs 3478

347978 GLOSSARY 3480

3481 Acceptance test – a test carried out after new equi pment has been installed or major 3482 modifications have been made to existing equipment, in order to verify compliance with the 3483 manufacturer’s specifications, contractual specific ations, and applicable local regulations or 3484 equipment standards 3485 Adequate image – an image that provides the informa tion needed to answer the clinical question 3486 at an optimized dose, i.e., the lowest dose possibl e to produce that image 3487 Adequate image quality – image quality sufficient f or the clinical purpose. Whether the image 3488 quality is adequate depends on the modality being u sed and the clinical question being asked. 3489 ALARA (as low as reasonably achievable) – a princip le of radiation protection philosophy that 3490 requires that exposures to ionizing radiation be ke pt as low as reasonably achievable, 3491 economic and social factors being taken into accoun t. The protection from radiation exposure 3492 is ALARA when the expenditure of further resources would be unwarranted by the reduction 3493 in exposure that would be achieved. 3494 Ancillary personnel – personnel beyond the operatio nal medical staff who provide support 3495

services 3496 Angiography – radiography of vessels after the inje ction of a radiopaque contrast material; 3497 usually requires percutaneous insertion of a radiop aque catheter and positioning under 3498 fluoroscopic control (Stedman 2006) 3499 Attenuation – reduction in radiation intensity, suc h as via the use of shielding 3500 Backscatter (as opposed to scatter) – a Compton sca ttering event in which a photon strikes an 3501 object and deflects at an angle greater than 90°, i .e., in a direction back toward its source 3502 Beam indicating device (BID) – a lead lined tube at tached to an x-ray tube head through which 3503 the primary x-ray beam will travel, used by the ope rator, especially in a dental setting, to align 3504 the beam with the image receptor 3505 Benefit – the probability or quantifiable likelihoo d that health will improve or deterioration will 3506 be prevented as a result of performing or not perfo rming a medical procedure 3507 Benefit:risk ratio – a determination (possibly subj ective) of the benefit to the patient from 3508 undergoing a procedure involving imaging using ioni zing radiation compared with the risk to 3509 the patient from receiving a radiation dose associa ted with the consequent imaging. 3510 Maximizing the benefit:risk ratio involves balancin g the benefit:risk ratio to the patient from 3511 an x-ray procedure against that from alternatives ( e.g., ultrasound, MRI, or no action). 3512 Bone densitometry – the noninvasive measurement of certain physical characteristics of bone 3513 that reflect bone strength (typically reported as b one mineral content or bone mineral density) 3514 and used for diagnosing osteoporosis, estimating fr acture risk, and monitoring changes in 3515

bone mineral content 3516

Collimator – a device used to reduce the cross-sect ional area of the useful beam of photons or 3517 electrons with an absorbing material 3518 Computed radiography (CR; also see DR) – a projecti on x-ray imaging method in which a 3519 cassette houses a sensor plate rather than photogra phic film. This photo-stimulable phosphor3520 coated plate captures a latent image when exposed t o x-rays and, when processed, releases 3521 light that is converted to a digital image. 3522 Computed tomography (CT) – an imaging procedure tha t uses multiple x-ray transmission 3523 measurements and a computer program to generate tom ographic images of the patient (NCRP 3524 2000) 352579

Cone – an open-ended device on a dental x-ray machi ne designed to indicate the direction of the 3526 central ray and to serve as a guide in establishing a desired source-to-image receptor distance 3527 (NCRP 2000) 3528 Cone Beam Computed Tomography system (CBCT) – A dig ital volume tomography method 3529 used in some imaging applications using two dimensi onal digital detector arrays, and a cone3530 shape x-ray beam (instead of fan-shaped) that rotat es around the patient to generate a high3531 resolution, 3D image, with high geometric accuracy. Reconstruction algorithms can be used 3532 to generate images of any desired plane. 3533 Credential – diploma, certificate, or other evidenc e of adequate educational performance that 3534 gives one a title or credit 3535

CTDI vol – a radiation dose parameter derived from the CTDI

w (weighted or average CTDI given 3536 across the field of view). The formula is: 3537

CTDI vol = N·T·CTDI

w / I, where 3538 N = number of simultaneous axial scans per x-ray so urce rotation, 3539 T = thickness of one axial scan (mm), and 3540 I = table increment per axial scan (mm). 3541

Deterministic effects – effects that occur in all i ndividuals who receive greater than the threshold 3542 dose and for which the severity of the effect varie s with the dose (NCRP 2003) 3543 Diagnosis – the determination of the nature of a di sease, injury, or congenital defect (Stedman 3544 2006) 3545 Digital radiography (DR) – an x-ray imaging method (or radiography) which produces a digital 3546 rather than film projection image. Includes both C R and DDR 3547 Direct digital radiography (DDR; also see CR and DR ) – an x-ray imaging method in which a 3548 digital sensor, rather than photographic film, is u sed to capture an x-ray image. DDR is a 3549 cassette-less imaging method (providing faster acqu isition time than cassette-based CR) using 3550 an electronic sensor that converts x-rays to electr onic signals (charge or current) when 3551 exposed to x-rays. 3552 Dose – a measure of the energy deposited by radiati on in a target. Used in this report as a 3553 generic term unless context refers to a specific qu antity, such as absorbed dose, committed 3554 equivalent dose, committed effective dose, effectiv e dose, equivalent dose or organ dose, as 3555 indicated by the context. 3556 Cumulative air kerma – sum of the kinetic energy r eleased to a small volume of air at a 3557 specific point in space during a specified event ortime frame when irradiation by an x3558 ray beam 3559

Cumulative dose – total radiation dose from all del ivered to any specific organ or tissue 3560 Dose area product (DAP), also called kerma-area pro duct (KAP) – the product of the air 3561

kerma and the area of the irradiated field and is m easured in Gy·cm 2 , so it does not 3562 change with distance from the x-ray tube. A good m easure of total energy delivered to 3563 the patient, and of stochastic risk. Not a good in dicator of deterministic risk 3564 Dose alert value - a value of CTDIvol (in units of mGy) or of DLP (in units of mGy·cm) 3565 that is set by the operating institution to trigger an alert to the operator prior to 3566 scanning within an ongoing examination if it would be exceeded by an accumulated 3567 dose index, on acquisition of the next confirmed pr otocol element group. An alert 3568 value represents a value above which the accumulate d dose index value would be well 3569 above the institution’s established range for the e xamination that warrants more 3570 stringent review and consideration before proceedin g. (see dose notification value) 357180

Dose equivalent – the product of the absorbed dose at a point in the tissue or organ and 3572 the appropriate quality factor for the type of radi ation giving rise to the dose 3573 Dose length product (DLP) – an indicator of the int egrated radiation dose from a 3574 complete CT examination. It addresses the total sc an length by the formula DLP = 3575

CTDI vol x scan length, with the units mGy-cm. 3576 Dose notification value - A value of CTDIvol (in un its of mGy) or of DLP (in units of 3577 mGy·cm) that is set by the operating institution to trigger a notification to the operator 3578 prior to scanning when exceeded by a corresponding dose index value expected for the 3579 selected protocol element. A notification value re presents a value above which a dose 3580

index value would be above the institution’s establ ished range for the protocol 3581 element. (see dose alert value) 3582 Dose registry – see registry 3583

Effective dose – ( E )

– the sum of the weighted equivalent doses for the ra diosensitive 3584 tissues and organs of the body. It is given by the expression E = Σ T ( w T H T ), in which 3585

H T is the equivalent dose in tissue or organ T and w T is the tissue weighting factor for 3586 tissue or organ T. The unit of E and H T is joule per kilogram (J kg –1 ), with the special 3587 name sievert (Sv) (see equivalent dose and tissue weighting factor ). 3588 Equivalent dose (formerly dose equivalent) – ( H T ): the mean absorbed dose (D T ) in a 3589 tissue or organ modified by the radiation weighting factor (w R ) for the type and energy 3590 of the radiation. The quantity HT,R, defined as H T,R = w R ⋅ D T,R , where D T,R is the 3591 absorbed dose delivered by radiation type R average d over a tissue or organ T and w R 3592 is the radiation weighting factor for radiation typ e R (IAEA 2011a). The unit for H T is 3593 J kg –1 , with the special name sievert (Sv). 3594 Reference point dose – radiation dose at the refere nce point, selected for reporting 3595 purposes, which is located at the center or in the central part of the planning target 3596 volume (PTV) 3597

Skin dose – radiation dose to the dermis 3598 Dosimeter – dose measuring device (NCRP 2003) 3599 Electronic Health Record (EHR) – an electronic reco rd of health-related information on an 3600 individual that is created, gathered, managed, and consulted by authorized health 3601 professionals and staff (Congress 2007) 3602 Exposure – in this report, exposure is used most often in its general sense, meaning to be 3603 irradiated. When used as the specifically defined radiation quantity, exposure is a measure of 3604 the ionization produced in air by x or gamma radiat ion. The unit of exposure is coulomb per 3605 kilogram (C kg –1 ). The special unit for exposure is roentgen (R), w here 1 R = 2.58 × 10 –4 C 3606 kg –1

. 3607 Exposure categories – 3608 Medical exposure – exposure incurred by patients fo r the purpose of medical or dental 3609 diagnosis or treatment; by carers and comforters as sociated with medical, dental, and 3610 veterinary procedures; and by volunteers in a progr am of biomedical research involving their 3611

exposure 3612 Occupational exposure – exposure of workers incurre d in the course of their work 3613 Public exposure – exposure incurred by members of t he public from sources in planned 3614 exposure situations, emergency exposure situations, and existing exposure situations, 3615 including incidental medical exposure, but excludin g any occupational or prescribed medical 3616

exposure 361781

Film/film radiograph – film is a thin, transparent sheet of polyester or similar material coated on 3618

one or both sides with an emulsion sensitive to rad iation and light; a radiograph is a film or 3619 other record produced by the action of x-rays on a sensitized surface (NCRP 2003) 3620

Filtration – material in the useful beam that usual ly absorbs preferentially the less penetrating 3621 radiation (NCRP 2003) 3622 Fluoroscopy – the process of producing a real-time image using x-rays (NCRP 2003) 3623 Gamma ray – a photon emitted in the process of nucl ear transition or radioactive decay 3624 Gray (Gy) – the special SI name for the unit of the quantities absorbed dose and air kerma. 1 Gy 3625 = 1 J kg –1 (see rad, rem, gray, and Sievert) 3626 Guidance level – optimal range of detector exposure index values that should be based on patient 3627 body habitus, anatomical view, clinical question, a nd other relevant factors 3628 Health physics – the field of science concerned wit h radiation physics and radiation biology and 3629 their application to radiation protection. Health physicists may specialize in nuclear power, 3630 environmental and waste management, laws and regula tions, dosimetry, emergency response, 3631 medicine or a host of other sub-specialties where r adiation is utilized. Of particular interest 3632 for this document is the medical health physics sub -specialty. 3633 Health physicist – a health professional, with educ ation and specialist training in the concepts 3634 and techniques of applying physics in medical, envi ronmental, or occupational settings, or 3635 competent to practice independently in one or more of the subfield specialties of medical 3636 physics or in health physics 3637 Health professional – an individual who has been fo rmally recognized through appropriate 3638 national procedures to practice a profession relate d to health (e.g., medicine, dentistry, 3639 chiropractic, podiatry, nursing, veterinary medicin e) (adapted from (IAEA 2011a)) 3640 Helical – spiral in form; a curve traced on a cylin der (or human body) by the rotation of a point 3641 crossing its right section at a constant oblique an gle 3642 Image – representation of an object produced by mac hine-produced ionizing radiation 3643 Image receptor – a system for deriving a diagnostic ally usable image from the x-rays transmitted 3644 through the patient (NCRP 2003) 3645 Incidental exposure – exposure not associated with the primary purpose for which it was 3646

delivered 3647 Informed consent – voluntary agreement given by a p erson or a patients' responsible proxy (e.g., 3648 a parent) for participation in a study, immunizatio n program, treatment regimen, invasive 3649 procedure, etc., after being informed of the purpos e, methods, procedures, benefits, and risks. 3650

The essential criteria of informed consent are that the subject has both knowledge and 3651 comprehension, that consent is freely given without duress or undue influence, and that the 3652 right of withdrawal at any time is clearly communic ated to the patient. Other aspects of 3653 informed consent in the context of epidemiologic an d biomedical research, and criteria to be 3654 met in obtaining it, are specified in International Guidelines for Ethical Review of 3655 Epidemiologic Studies (Chanaud 2008; Stedman 2006)( Geneva: CIOMS/WHO 1991) and 3656

International Ethical Guidelines for Biomedical Res earch Involving Human Subjects (Geneva: 3657 CIOMS/WHO 1993). 3658 Intensifying screen – a device consisting of fluore scent material, which is placed in contact with 3659 the film in a radiographic cassette. Radiation int eracts with the fluorescent material, releasing 3660 light photons. (adapted from (NCRP 2003) 366182

Interlock – device that automatically shuts off or reduces the radiation emission rate from an 3662 accelerator to acceptable levels ( e.g ., by the opening of a door into a radiation area). In 3663 certain applications, an interlock can be used to p revent entry into a treatment room. 3664 Intervention – any measure taken to alter the cours e of medical diagnosis whose purpose is to 3665 improve a health outcome 3666 Isocenter – the small point in space (or generally spherical or elliptical volume) where radiation 3667 beams emitted during the rotational swing of an x-r ay tube gantry intersect 3668 Justification – the process of determining for a pl anned exposure situation whether a practice is, 3669 overall, beneficial, i.e. whether the expected bene fits to individuals and to society from 3670 introducing or continuing the practice outweigh the harm (including radiation detriment) 3671 resulting from the practice (IAEA 2011a) 3672 Kerma (kinetic energy released per unit mass, or ki netic energy released in matter) – the sum of 3673 the initial kinetic energies of all the charged par ticles liberated by uncharged particles (e.g., x3674 rays) in a material of mass δ m (IAEA 2011a). The unit for kerma is J kg–1, with the special 3675 name gray (Gy). Kerma can be quoted for any specifi ed material at a point in free space or in 3676 an absorbing medium ( e.g ., air kerma). 3677 Kerma-area product (KAP, also called dose-area prod uct or DAP) – the product of the air kerma 3678

and the area of the irradiated field and is measure d in Gy·cm 2 , so it does not change with 3679 distance from the x-ray tube. A good measure of to tal energy delivered to the patient, and of 3680 stochastic risk. Not a good indicator of determini stic risk. 3681 Licensed independent practitioner – any individual permitted by law and by the organization to 3682 provide care and services, without direction or sup ervision, within the scope of the 3683

individual's license and consistent with individual ly granted clinical privileges (see Referring 3684 Medical Practitioner and Radiological Medical Pract itioner) 3685 Mammography – the use of x-rays to produce a diagno stic image of the breast 3686 Medical exposure – exposure incurred by patients fo r the purposes of medical or dental diagnosis 3687 or treatment; by careres and comforters; and by vol unteers subject to exposure as part of a 3688 program of biomedical research (IAEA 2011a) 3689 Medical health physics – the profession dedicated t o the protection of healthcare providers, 3690 members of the public, and patients from unwarrante d radiation exposure. Medical health 3691 physicists are knowledgeable in the principles of h ealth physics and in the applications of 3692 radiation in medicine. While medical physics and m edical health physics have a number of 3693 similarities and overlapping fields of study and in terest, the emphasis of practice or day-to3694 day routines are different. 3695 Medical physics
– a field of science concerned with applying physics to medical imaging and 3696 determining patient dose. The Medical Physicist's clinical practice focuses on methods to assure 3697 the safe and effective delivery of radiation to ach ieve a diagnostic or therapeutic result as 3698 prescribed in patient care. 3699 Medical physicist – a health professional, with edu cation and specialist training in the concepts 3700 and techniques of applying physics in medicine, com petent to practice independently in one or 3701 more of the subfield specialties of medical physics (IAEA 2011a) 3702 Medical technologist – a health professional, with specialist education and training in medical 3703 radiation technology, competent to carry out radiol ogical procedures, on delegation from the 3704 radiological medical practitioner, in one or more o f the specialties of medical radiation 3705 technology (IAEA 2011a) 370683

Members of the public – all persons who are not alr eady considered occupationally exposed by a 3707 source or practice under consideration. When being irradiated as a result of medical care, 3708 patients are a separate category. 3709 Occupational exposure – exposure to an individual t hat is incurred in the workplace as a result of 3710 situations that can reasonably be regarded as being the responsibility of management 3711 (exposures associated with medical diagnosis or tre atment for the individual are excluded). 3712 (NCRP 2003) 3713 Optically stimulated luminescent (OSL) dosimeter – a dosimeter containing a crystalline solid 3714 for measuring radiation dose, plus filters to help characterize the types of radiation 3715 encountered. When irradiated with intense light, O SL crystals that have been exposed to 3716 ionizing radiation give off light proportional to t he energy they receive from the radiation 3717 (NCRP 2003). 3718 Optimal dose – the minimum radiation dose required to be delivered by an x-ray imaging system 3719 to produce an image that is of adequate quality for the intended purpose. This requires that 3720 the x-ray generator and imaging equipment to be wor king appropriately, (see adequate image). 3721 Optimization of protection – the process of determi ning what level of protection and safety 3722 would result in the magnitude of individual doses, the number of individuals (workers and 3723 members of the public) subject to exposure and the likelihood of exposure being “as low as 3724 reasonably achievable, economic and social factors being taken into account” (ALARA) (as 3725 required by the System of Radiological Protection). For medical exposures of patients, the 3726 optimization of protection and safety is the manage ment of the radiation dose to the patient 3727 commensurate with the medical purpose. “Optimizati on of protection and safety” means that 3728 optimization of protection and safety has been appl ied and the result of that process has been 3729 implemented. (IAEA 2011a) 3730 Personal protective equipment – specialized clothin g or equipment (e.g., leaded or tungsten 3731 apron, gloves, thyroid collar, eyeglasses) worn by an employee to protect against a hazard. 3732 General work clothes not intended to serve as a pro tection against a hazard are not considered 3733 to be personal protective equipment. 3734 Phantom – as used in this report, a volume of tissu e- or water-equivalent material used to 3735 simulate the absorption and scattering characterist ics of the patient’s body or portion thereof 3736 Picture archiving and communications system (PACS) – electronic system for the archival 3737 storage and transfer of information associated with x-ray images 3738 Pitch – in CT, table incrementation per x-ray tube rotation divided by the nominal x-ray beam 3739

width at isocenter 3740 Prescribe – the process of requesting or ordering a n exam to be performed, or the process of 3741 determining how an exam should be done in order to optimize the choice of study and 3742 protocol, and optimize the radiation dose 3743 Protocol – selected parameters for image acquisitio n that defines the portion of the patient’s 3744 anatomy to be imaged, whether and how contrast agen ts will be administered, the number and 3745 timing of imaging sequences, and acquisition techni cal parameters (pitch, collimation or beam 3746 width, kV, mA (constant or modulated and specifying the parameters determining the balance 3747 between image noise and patient dose), rotation tim e, physiologic gating, image quality 3748 factors, and reconstruction method 3749 Pulsed (as in pulsed fluoroscopy) – x-rays not prod uced continuously, but in rapid succession as 3750 pulses. Reduces dose by using a lower pulse rate ( e.g., 15 or 7.5 pulses/sec) and in 3751 conjunction with digital image memory to provide a continuous video display 375284

Qualified expert – an individual who, by virtue of certification by appropriate boards or societies, 3753 professional licenses or academic qualifications an d experience, is duly recognized as having 3754 expertise in a relevant field of specialization, e. g. medical physics, radiation protection

, 3755 occupational health, fire safety, quality assurance or any relevant engineering or safety 3756 specialty (IAEA 2011a) 3757 Qualified physicist – an individual who is competen t to practice independently in the relevant 3758 medical subfield of medical physics or health physi cs. In general, a health physicist or 3759 medical physicist with appropriate training and exp erience regarding the medical use of x-rays 3760 is considered a qualified physicist. Ideally, pers ons should have certification from the 3761 American Board of Health Physics, the American Boar d of Medical Physics, the American 3762 Board of Radiology, or the American Board of Indust rial Hygiene, to be considered a 3763 qualified expert in these respective fields. For t he purposes of this document, the relevant 3764 subfield of medical physics is diagnostic radiologi cal physics. Certification, continuing 3765 education, and experience are factors toward demons trating that an individual is a qualified 3766 physicist. Individual federal agencies may develop their own criteria for determining when a 3767 physicist is a “Qualified Physicist” as defined in this document. 3768 Qualified medical physicist – an individual who is competent to practice independently in the 3769 relevant subfield of medical physics. For the purp oses of this document, the relevant subfield 3770 is diagnostic radiological physics. Certification and continuing education and experience in 3771 the relevant subfield is one way to demonstrate tha t an individual is competent to practice in 3772 that subfield of medical physics and to be a qualif ied medical physicist. 3773 Quality assurance – the function of a management sy stem that provides confidence that specified 3774 requirements will be fulfilled 3775 Rad – the special (traditional or historical) name for the unit of absorbed dose. 1 rad = 0.01 J kg 3776

1 . In the SI system of units, it is replaced by the special name gray (Gy). 1 Gy = 100 rad 3777 (NCRP 2000). (see rad, rem, gray, and Sievert) 3778 Radiation Safety Officer – the individual whose res ponsibility it is to ensure adequate protection 3779 of workers and the public from exposure to ionizing radiation 3780 Radiation weighting factor, w R – a number (as specified in the System for Radiolo gical 3781 Protection) by which the absorbed dose in a tissue or organ is multiplied to reflect the relative 3782 biological effectiveness of the radiation in induci ng stochastic effects at low doses, the result 3783 being the equivalent dose (IAEA 2011a) 3784 Radiography – the production of images on film or o ther record by the action of x-rays 3785 transmitted through the patient (NCRP 2003) 3786 Radiological Medical Practitioner – a health profes sional with specialist education and training 3787 in the medical uses of radiation, who is competent to perform independently or to oversee 3788 procedures involving medical exposure in a given sp ecialty (IAEA 2011a) (see licensed 3789 independent practitioner) 3790 Reference dose, patient entrance reference dose (or reference air kerma, reference dose, 3791 cumulative dose, cumulative air kerma, K A,R ) – the dose at the patient entrance reference 3792 point. For C-arm fluoroscopic equipment, this is a lso known as the interventional reference 3793 point, and is located along the central ray of the x-ray beam, 15 cm back from the isocenter 3794 toward the x-ray tube. The isocenter is the centra l point about which the C-arm rotates. 3795 Reference dose is measured in Gy and is not the sam e as skin dose (IEC 2008). 379685

Reference level – a level used in medical imaging t o indicate whether, in routine conditions, the 3797 dose to the patient in a specified radiological pro cedure is unusually high or low for that 3798 procedure 3799 Referring Medical Practitioner – a health professio nal who, in accordance with national 3800 requirements, may refer individuals to a radiologic al medical practitioner for medical 3801 exposure (IAEA 2011a) (see licensed independent pra ctitioner) 3802 Registry – central national repository for patient radiation dose and equipment parameter data 3803 Rem – the special (traditional or historical) name for the unit of dose equivalent numerically 3804 equal to the absorbed dose (D) in rad, modified by a quality factor (Q). 1 rem = 0.01 J kg -1 . In 3805 the SI system of units, it is replaced by the speci al name sievert (Sv), which is numerically 3806 equal to the absorbed dose (D) in gray modified by a radiation weighting factor ( ω R ). 1 Sv = 3807 100 rem (NCRP 2003). (see rad, rem, gray, and Siev ert) 3808 Resolution – in the context of an imaging system, t he output of which is finally viewed by the 3809 eye, it refers to the smallest size or highest spat ial frequency of an object of given contrast that 3810 is just perceptible. The resolution actually achie ved with imaging lower contrast objects is 3811 normally much less, and depends upon many variables such as subject contrast levels and 3812 noise of the overall imaging system (NCRP 2003). 3813 Risk – the probability or quantifiable likelihood t hat a detriment to health will occur as a result of 3814 performing or not performing a medical procedure 3815 Roentgen – the special name for exposure, which is a specific quantity of ionization (charge) 3816 produced by the absorption of x- or gamma-radiation energy in a specified mass of air under 3817

standard conditions. 1 R = 2.58 x 10 -4 coulombs per kilogram (C kg -1 ) (NCRP 2003). 3818 Screening – the evaluation of an asymptomatic perso n in a population to detect a disease process 3819

not known to exist at the time of evaluation 3820 Sievert (Sv) - the special SI name for the quantiti es equivalent dose or effective dose. 3821 Equivalent dose is the radiation protection quantit y used for setting limits that help ensure that 3822 deterministic effects (e.g. damage to a particular tissue) are kept within acceptable levels. The 3823 SI unit of equivalent dose is the J kg -1 , and is abbreviated H T . It is numerically equal to a 3824 radiation weighting factor ( ω R ) [or quality factor (Q)] multiplied by the absorbe d dose in 3825 tissue T (D T,R ). 1 Sv = 100 rad (NCRP 2003). The formula is: 3826

H T = ∑ R ω R D T,R or ∑ R Q R D T,R 3827

where 3828

ω R = radiation weighting factor, 3829

D T,R = absorbed dose to tissue T from radiation type R, and 3830 Q R = quality factor. 3831

3832 Effective dose is the radiation protection quantity used for setting limits that help ensure that 3833 stochastic effects (i.e., cancer and genetic effect s) are kept within acceptable levels. The SI 3834 unit of effective dose is the J kg -1 , and is abbreviated H E . It is numerically equal to a radiation 3835 weighting factor ( ω R ) multiplied by a tissue weighting factor ( ω T ) and the absorbed dose from 3836 that radiation in tissue T (D T,R ) in gray. Identically, it is the equivalent dose multiplied by a 3837 tissue weighting factor. 1 Sv = 100 rem (NCRP 2003 ). The formula is: 3838

H E = ∑ T ω T ∑ R ω R D T,R = ∑ T H T ω T 3839

where 3840

H E = the effective dose (or effective dose equivalent ) to the entire individual, 3841

ω T = the tissue weighting factor in tissue T, 384286

H T = the equivalent dose (or dose equivalent), 3843

ω R = the radiation weighting factor, and 3844

D T,R = the absorbed dose to tissue T from radiation typ e R. 3845 (see rad, rem, gray, and Sievert) 3846 Signal to noise ratio – the ratio of input signal t o background interference. The greater the ratio, 3847 the clearer the image (NCRP 2003). 3848 Skin dose – radiation dose to the dermis, measured for example as entrance skin dose or peak 3849

skin dose 3850

Slice – a 2-dimensional reconstructed cross-section al image depicting a patient’s anatomy 3851 produced using x-rays, MRI, ultrasound, or other no n-invasive means 3852 Step wedge – a device with various thicknesses of a luminum used to verify the consistency of 3853 the x-ray and film processing systems. Typically e ach step of the stepwedge is about 1 mm 3854 thick and about 3 to 4 mm wide with at least 6 step s. The device is placed on a film cassette 3855 and exposed under the exact same exposure parameter s and geometry set up. The film is then 3856 developed and the steps are visually compared to th e reference film identically exposed and 3857 processed in fresh solutions under ideal conditions . A reproducible change of one step or 3858 more in density should signal the need for correcti ve action. 3859 Stochastic effects – effects, the probability of wh ich, rather than their severity, is a function of 3860 radiation dose, implying the absence of a threshold . More generally, stochastic means random 3861 in nature (NCRP 2003). 3862 Supervision, general – means the procedure is furni shed under the supervising individual’s 3863 overall direction and control, but the supervising individual’s presence is not required during 3864 the performance of the procedure. Under general su pervision, the training of the personnel 3865 who actually perform the task and the maintenance o f the necessary equipment and supplies 3866 are the continuing responsibility of the supervisin g individual (adapted from (DHHS 2012a) 3867 Supervision, direct – means the supervising individ ual must be present in the local area (for 3868 physicians, in the office suite) and immediately av ailable to furnish assistance and direction 3869 throughout the performance of the procedure. It do es not mean that the supervising individual 3870 must be present in the room when the task is perfor med (adapted from (DHHS 2012a)). 3871 Supervision, personal – means a supervising individ ual must be in attendance in the room during 3872 the performance of the task (adapted from (DHHS 201 2a)) 3873 Technique factor – operator selectable parameter af fecting the x-ray beam (e.g., kV, mA, time) 3874 Tissue weighting factor, wT – multiplier of the equ ivalent dose to an organ or tissue, as given by 3875 the System for Radiological Protection, used for ra diation protection purposes to account for 3876 the different sensitivities of different organs and tissues to the induction of stochastic effects 3877 of radiation (IAEA 2011a) 3878 Tomography – a special technique to show in detail images of structures lying in a 3879 predetermined plane of tissue, while blurring or el iminating detail in images of structures in 3880 other planes (NCRP 2003) 3881 Total effective dose equivalent (TEDE) – the sum of the deep-dose equivalent (for external 3882 exposures) and the committed effective dose equival ent (for internal exposures) 3883 Universal Protocol – A Joint Commission process dev eloped to address wrong site, wrong 3884 procedure, and wrong person surgeries and other pro cedures. The three principal components 3885 of the Universal Protocol include a pre-procedure v erification, site marking, and a timeout 3886 (The Joint Commission 2012a; The Joint Commission 2 012b) 388787

Worker – any person who works, whether full time, p art time or temporarily, for an employer 3888 and who has recognized rights and duties in relatio n to occupational radiation protection 3889 (IAEA 2011a) 3890A-1 3891

APPENDIX A – NIH INFORMED CONSENT TEMPLATES 3892

3893

3894 The guidance in this appendix is suitable for resea rch involving diagnostic and interventional x3895 ray procedures. It applies to radiation use indica ted for research involving human subjects. 3896 Examples might include evaluating new mammography p rotocol using lower kVp as 3897 recommended by ICRP, virtual colonoscopy, and natio nal lung screening trials. It excludes 3898 radiation oncology research, in which radiation dos es to subjects may be much higher. A 3899 discussion of human subjects research ethics, patie nt benefit:risk considerations, and the role of 3900 Institutional Review Boards is beyond the scope of this document, but is an essential process 3901 prior to the conduct of research involving human su bjects. 3902

3903 The risk from research protocols involving radiatio n use indicated for research, as described 3904 above, can be categorized into groups. A useful ap proach is to group risk as minimal, minor to 3905 intermediate, or moderate. The templates on the fo llowing pages are adapted from those used by 3906 the NIH in 2012 (less than 1 mSv (100 mrem) “minima l” and 1-50 mSv (100 mrem – 5 rem) 3907 “minor to intermediate”). Doses above 50 mSv (5 re m) may be considered to range from 3908 moderate to substantial. The specific ranges and t ext may be adjusted as required by the specific 3909 IRB (NIH 2001; NIH 2008a; NIH 2008b; NIH 2010). An other approach to selecting the dose 3910 ranges and descriptors for these templates is shown below. 3911

3912 Classification schemes for use of E as a qualitativ e indicator of stochastic risk for diagnostic and interventional x-ray procedures Range of E (mSv) Radiation Risk Descriptor Expected Minimum

Individual or Societal Benefit ICRP Martin (2007) NCRP <0.1 Trivial Negligible Negligible Describable

0.1-1 Minor Minimal Minimal Minor

1-10 Intermediate Very low Minor Moderate

10-100 Moderate Low Low Substantial >100 - - Acceptable (in

context of the expected benefit) Justifiable expectation of very

substantial individual benefit

Adapted from: (ICRP 1991b; Martin 2007)

3913

3914

3915A-2

MINIMAL RISK 3916 Adapted from NIH TEMPLATE A (Total effective dose less than or equal to 1 mSv ( 100 mrem)) 3917

3918 This research study involves exposure to radiation from ( insert type of procedure or procedures ). 3919 Please note that this radiation exposure is not necessary for your medical care and is for research 3920 purposes only. 3921

3922 The total amount of radiation you will receive in t his study is from ( insert maximum number ) of 3923 ( insert description of type of x-ray procedure )

. The Radiation Safety Committee has reviewed 3924 the use of radiation in this research study and has approved this use as involving minimal risk 3925 and necessary to obtain the research information de sired. 3926

3927 You will receive a total of ( XX) mSv or (YY) rem to your (insert highest-dosed organ, typically 3928 skin) from participating in this study. All other parts of your body will receive smaller amounts 3929 of radiation. Although each organ will receive a d ifferent dose, the amount of radiation exposure 3930 you will receive from this study is equal to a unif orm whole-body exposure of less than ( insert 3931 total effective dose value ). This calculated value is known as the “effectiv e dose” and is used to 3932 relate the dose received by each organ to a single value. 3933

3934 For comparison, the average person in the United St ates receives a radiation dose of 3 mSv (300 3935 mrem) per year from natural background sources, suc h as from the sun, outer space, and from 3936 radioactivity found naturally in the earth’s air an d soil. The dose that you will receive from 3937 participation in this research study is about the s ame amount you would normally receive in 3938 (insert number) months from these natural sources. 3939

3940

While there is no direct evidence that the small ra diation dose received from participating 3941 in this study is harmful, there is indirect evidenc e it may not be completely safe. There 3942 may be an extremely small increase in the risk of c ancer. 3943

3944A-3

MINOR TO INTERMEDIATE RISK 3945 Adapted from NIH TEMPLATE B ( 1 mSv < Total effective dose = < 50 mSv ) or (100 mrem < 3946 Total effective dose = < 5 rem) 3947

3948 This research study involves exposure to radiation from ( insert type of procedure or procedures ). 3949 Please note that this radiation exposure is not necessary for your medical care and is for research 3950 purposes only. 3951

3952 The total amount of radiation you will receive in t his study is from ( insert maximum number ) 3953 ( scans or repetitions ) of ( insert description of type of x-ray procedure )

. The Radiation Safety 3954

Committee has reviewed the use of radiation in this research study and has approved this use as 3955 involving low risk (more than minimal but less than moderate) and necessary to obtain the 3956

research information desired. 3957

3958 Although each organ will receive a different dose, the amount of radiation exposure you will 3959 receive from this study is equal to a uniform whole -body exposure of less than ( insert total 3960 effective dose value ). This calculated value is known as the “effectiv e dose” and is used to relate 3961 the dose received by each organ to a single value. The amount of radiation you will receive in 3962 this study is less than the annual radiation dose o f 50 mSv per year (5 rem per year) permitted for 3963 someone who works with radiation on a daily basis. 3964

3965 For comparison, the average person in the United St ates receives a radiation dose of 3 mSv (300 3966 mrem) per year from natural background sources, suc h as from the sun, outer space, and from 3967 radioactivity found naturally in the earth’s air an d soil. The dose that you will receive from 3968 participation in this research study is about the s ame amount you would normally receive in 3969 (insert number) months from these natural sources. 3970

3971 The effects of radiation exposure on humans have be en studied for over 60 years. In fact, these 3972 studies are the most extensive ever done of any pot entially harmful agent that could affect 3973 humans. In all these studies, no harmful effect to humans has been observed from the levels of 3974 radiation you will receive by taking part in this r esearch study. However, scientists disagree on 3975

whether radiation doses at these levels are harmful . Even though no effects have been observed, 3976

some scientists believe that radiation can be harmf ul at any dose - even low doses such as those 3977 received during this research. 3978

3979

While there is no direct evidence that the radiatio n dose received from participating in this 3980 study is harmful, there is indirect evidence it may not be completely safe. There may be a 3981

small increase in the risk of cancer. 3982

3983 (INCLUSION OF THIS PARAGRAPH IS OPTIONAL) Some people may be concerned that 3984 radiation exposure may have an effect on fertility or cause harm to future children. The radiation 3985 dose you will receive in this research study is wel l below the level that affects fertility. In 3986 addition, radiation has never been shown to cause h arm to the future children of individuals who 3987 have been exposed to radiation. Harm to future gen erations has been found only in experiments 3988

on animals that have received radiation doses much higher than the amount you will receive in 3989 this study. 3990REF-1 3991

REFERENCES 3992

3993

3994 AAPM. 1998. AAPM Report No. 58: Managing the use of Fluoroscopy in Medical Institutions. 3995 American Association of Physicists in Medicine. 3996 AAPM. 2005. AAPM TG18 On-line Report No. 03: Assess ment of Display Performance for 3997 Medical Imaging Systems. College Park, MD: American Association of Physicists in 3998

Medicine. 3999 AAPM. 2006a. AAPM Report No. 93: Acceptance Testing and Quality Control of 4000 Photostimulable Storage Phosphor Imaging Systems. A merican Association of Physicists 4001

in Medicina. 4002 AAPM. 2006b. AAPM Report No. 94: validating Automat ic Film Processor Performance. 4003 American Association of Physicists in Medicine. 4004 AAPM. 2006c. AAPM Report Task Group 108: PET and PE T/CT Shielding requirements. 4005 Medical Physics 33(1):4-15. 4006 AAPM. 2009. AAPM Report No. 116: An Exposure Indica tor for Digital Radiography. College 4007 Park, MD: American Association of Physicists in Med icine. 4008 ACR. 2006a. ACR practice guideline on informed cons ent for image-guided procedures. Practice 4009 Guidelines and Technical Standards 2007. Reston, VA : American College of Radiology. 4010 ACR. 2006b. ACR technical standard for diagnostic m edical physics performance monitoring of 4011 radiographic and fluoroscopic equipment. Practice G uidelines and Technical Standards 4012 2007. Reston, VA: American College of Radiology. 4013 ACR. 2007a. ACR practice guideline for digital radi ography. Practice Guidelines and Technical 4014 Standards 2007. Reston, VA American College of Rad iology. 4015 ACR. 2007b. ACR technical standard for diagnostic m edical physics performance monitoring of 4016 computed tomography (CT) equipment. Practice Guidel ines and Technical Standards 4017 2007. Reston, VA: American College of Radiology. 4018 ACR. 2007c. ACR technical standard for electronic p ractice of medical imaging. Practice 4019 Guidelines and Technical Standards 2007. Reston, VA : American College of Radiology. 4020 ACR. 2007d. American College of Radiology white pap er on radiation dose in medicine. J Am 4021

Coll Radiol 4:13. 4022 ACR. 2008a. ACR-SSR practice guideline for the perf ormance of dual-energy x-ray 4023 absorptiometry (DXA). Practice Guidelines and Techn ical Standards 2007. Reston, VA: 4024 American College of Radiology. 4025 ACR. 2008b. ACR practice guideline for diagnostic r eference levels in medical X-ray imaging. 4026

Practice Guidelines and Technical Standards 2008. R eston, VA: American College of 4027 Radiology. p 799-804. 4028 ACR. 2008c. ACR technical standard for management o f the use of radiation in fluoroscopic 4029 procedures. Practice Guidelines and Technical Stand ards 2008. Reston, VA American 4030 College of Radiology. p 1143-1149. 4031 ACR. 2009a. ACR-SIIM practice guideline for electro nic medical information privacy and 4032 security. Practice Guidelines and Technical Standar ds 2007. Reston, VA: American 4033 College of Radiology. 4034REF-2

ACR. 2009b. ACR practice guideline for the performa nce of computed tomography (CT) 4035 colonography in adults. Practice Guidelines and Tec hnical Standards 2007. Reston, VA: 4036 American College of Radiology. 4037 ACR. 2010. ACR practice guideline for communication of diagnostic imaging findings. Reston, 4038 VA: American College of Radiology. 4039 ACR. 2012. ACR appropriateness criteria. Practice G uidelines and Technical Standards 2007, 4040 Last update 2012. Reston, VA: American College of R adiology. 4041 ADA FDA. 2004 The selection of patients for dental radiographic examinations. 4042 Amis ES, Jr., Butler PF, Applegate KE, Birnbaum SB, Brateman LF, Hevezi JM, Mettler FA, 4043 Morin RL, Pentecost MJ, Smith GG and others. 2007. American College of Radiology 4044 white paper on radiation dose in medicine. J Am Col l Radiol 4(5):272-84. 4045 Aroua A, Rickli H, Stauffer JC, Schnyder P, Trueb P R, Valley JF, Vock P, Verdun FR. 2007. 4046 How to set up and apply reference levels in fluoros copy at a national level. Eur Radiol 4047 17(6):1621-33. 4048 Balter S, Hopewell JW, Miller DL, Wagner LK, Zelefs ky MJ. 2010. Fluoroscopically guided 4049 interventional procedures: a review of radiation ef fects on patients' skin and hair. 4050 Radiology 254(2):326-41. 4051 Balter S, Miller DL. 2007. The new Joint Commission sentinel event pertaining to prolonged 4052 fluoroscopy. Journal of the American College of Rad iology 4(7):497-500. 4053 Balter S, Miller DL, Vano E, Ortiz Lopez P, Bernard i G, Cotelo E, Faulkner K, Nowotny R, 4054 Padovani R, Ramirez A. 2008. A pilot study explorin g the possibility of establishing 4055 guidance levels in x-ray directed interventional pr ocedures. Med Phys 35(2):673-80. 4056 Balter S, Moses J. 2007. Managing patient dose in i nterventional cardiology. Catheterization and 4057 Cardiovascular Diagnosis 70:244-249. 4058 Balter S, Shope TB, Jr., Fletcher DW, Kuan HM, Chan RC. 2002. Techniques to estimate 4059 radiation dose to skin during fluoroscopically guid ed procedures. Intravascular 4060 brachytherapy. Fluoroscopically guided intervention s. Madison, WI: Medical Physics 4061 Publishing. p 731-764. 4062 Berrington de González A, Mahesh M, Kim K, et al. 2 009. PRojected cancer risks from 4063 computed tomographic scans performed in the united states in 2007. Archives of Internal 4064 Medicine 169(22):2071-2077. 4065 Bleeser F, Hoornaert MT, Smans K, Struelens L, Buls N, Berus D, Clerinx P, Hambach L, 4066 Malchair F, Bosmans H. 2008. Diagnostic reference l evels in angiography and 4067 interventional radiology: a Belgian multi-centre st udy. Radiat Prot Dosimetry 129(1- 4068 3):50-5. 4069 Bonnick SL, L. L. 2006. Bone densitometry for techn ologists: Humana Press. 4070 Brambilla M, Marano G, Dominietto M, Cotroneo AR, C arriero A. 2004. Patient radiation doses 4071 and references levels in interventional radiology. Radiol Med 107(4):408-18. 4072 Brenner D, Elliston C, Hall E, Berdon W. 2001. Esti mated risks of radiation-induced fatal cancer 4073 from pediatric CT. AJR Am J Roentgenol 176(2):289-9 6. 4074 Brenner DJ, Hall E.J. 2007. Computed Tomography — A n Increasing Source of Radiation 4075 Exposure. New England Journal of Medicine 357:2277- 2284. 4076

Carter J. 1978. Title 3 - The President: Radiation protection guidance to Federal agencies for 4077 diagnostic x-rays. In: Department E, editor. Washin gton, DC: Federal Register. p 4377- 4078

4380. 4079REF-3

Carter J. 1980. Executive Order 12196: Occupational Safety and Health Programs for Federal 4080 Employees. In: President Oot, editor. Washington, D C: White House. 4081

CDC. 2003. Guidelines for Infection Control in Dent al Health-Care Settings --- 2003. In: 4082 Prevention CfDCa, editor. Atlanta, GA: Morbidity an d Mortality Daily Report. p 1-61. 4083 Chambers CE, Fetterly KA, Holzer R, Lin PJ, Blanken ship JC, Balter S, Laskey WK. 2011. 4084 Radiation safety program for the cardiac catheteriz ation laboratory. Catheterization and 4085 Cardiovascular Interventions 77(4):546-56. 4086 Chanaud CM. 2008. Determination of required content of the informed consent process for 4087 human participants in biomedical research conducted in the U.S.: A practical tool to 4088 assist clinical investigators. Contemporary Clinica l Trials 29(4):501-506. 4089 Compagnone G, Baleni MC, Pagan L, Calzolaio FL, Bar ozzi L, Bergamini C. 2006. Comparison 4090 of radiation doses to patients undergoing standard radiographic examinations with 4091 conventional screen-film radiography, computed radi ography and direct digital 4092 radiography. British Journal of Radiology 79(947):8 99-904. 4093 Congress. 2004. OSH Act of 1970 as amended, Section 19, Federal agency safety programs and 4094 responsibilities. In: Congress US, editor. 4095 Congress. 2007. Health Information Technology for E conomic and Clinical Health Act 4096 (HITECH Act). XIII. 4097 D'Helft CJ, Brennan PC, McGee AM, McFadden SL, Hugh es CM, Winder JR, Rainford LA. 4098

2009. Potential Irish dose reference levels for car diac interventional examinations. Br J 4099 Radiol 82(976):296-302. 4100 DHHS. 2012a. 42CFR410.32: Diagnostic x-ray tests, d iagnostic laboratory tests, and other 4101 diagnostic tests: Conditions. In: Services DoHaH, e ditor. Title 42 Code of Federal 4102 Regulations Part 410.32. 4103 DHHS. 2012b. 45CFR164: Security and privacy. In: Se rvices DoHaH, editor. Title 45 Code of 4104 Federal Regulations Part 164. 4105 Dunn NL, Ha M, Radosevich AT. 2012. Main Group Redo x Catalysis: Reversible P(III)/P(V) 4106 Redox Cycling at a Phosphorus Platform. Journal of the American Chemical Society 2:2. 4107 EPA. 1976. Federal Guidance Report No. 9: Radiation Protection Guidance for Diagnostic X 4108 Rays. 4109 EPA. 2000. Radiation protection at EPA: The first 3 0 years. 4110 EPA. 2012. TItle 42 U.S.C. 2021(h): Cooperation wit h states - Consultative, advisory, and 4111

miscellaneous functions of Administrator of Environ mental Protection Agency. In: 4112 Congress US, editor. 4113 FDA. 1994. Avoidance of serious x-ray induced skin injuries to patients during fluoroscopically4114 guided procedures. In: Administration FaD, editor. 4115 FDA. 2001. FDA Public Health Notification: Reducing Radiation Risk from Computed 4116 Tomography for Pediatric and Small Adult Patients. In: Administration FaD, editor. 4117 FDA. 2010a. National Exposure to X-ray Trends. In: Administration FaD, editor. 4118 FDA. 2010b. Safety investigation of CT brain perfus ion scans: Update 12/8/2009. In: 4119 Administration FaD, editor. 4120

FDA. 2012a. 21CFR803.3: How does FDA define the ter ms used in this part? In: Administration 4121 FaD, editor. Title 21 Code of Federal Regulations P art 803.3. 4122 FDA. 2012b. 21CFR803: Medical device reporting. In: Administration FaD, editor. Title 21 4123 Code of Federal Regulations Part 803. 4124REF-4

FDA. 2012c. 21CFR900: Mammography. In: Administrati on FaD, editor. Title 21 Code of 4125 Federal Regulations Part 900. 4126

FDA. 2012d. 21CFR1020.32: Performance standards for ionizing radiation emitting products - 4127 Fluoroscopic equipment. 4128

FDA. 2012e. 21CFR1020: Performance standards for io nizing radiation emitting products. In: 4129 Administration FaD, editor. Title 21 Code of Federa l Regulations Part 1020. 4130

FDA. 2012f. 21CFR 1020.30: Performance standards fo r ionizing radiation emitting products - 4131 Diagnostic x-ray systems and their major components . In: Administration FaD, editor. 4132 Title 21 Code of Federal Regulations Part 1020.30. 4133 FDA. 2012g. 21CFR Subchapter J: Radiological health (parts 1000-1050). In: Administration 4134 FaD, editor. Title 21 Code of Federal Regulations S ubchapter J 4135 Fletcher DW, Miller DL, Balter S, Taylor MA. 2002. Comparison of four techniques to estimate 4136 radiation dose to skin during angiographic and inte rventional radiology procedures. 4137 Journal of Vascular and Interventional Radiology 13 (4):391-397. 4138 Freedman M, Pe E, Mun S, So S-C, Nelson M. 1993. Th e potential for unnecessary patient 4139 exposure from the use of storage phosphor imaging s ystems. Kim Y, editor. Medical 4140 Imaging 1993: Image Capture, Formatting, and Displa y. 4141 Genant HK, Jergas M, Palermo L, Nevitt M, Valentin RS, Black D, SR. C. 1996. Comparison of 4142 semiquantitative visual and quantitative morphometr ic assessment of prevalent and 4143 incident vertebral fractures in osteoporosis: The s tudy of osteoporotic fractures research 4144 group. J Bone Miner Res 11(7):984-996. 4145 Gibbs SJ. 2000. Effective dose equivalent and effec tive dose: Comparison for common 4146 projections in oral and maxillofacial radiology. Or al Surgery, Oral Medicine, Oral 4147 Pathology, Oral Radiology, and Endodontology 90(4): 538-545. 4148 Goren A, Bonvento M, Biernacki J, Colosi D. 2008. R adiation exposure with the NOMAD 4149 portable X-ray system. Dentomaxillofac Radiol 37(2) :109-112. 4150 Goske MJ, Applegate KE, Boylan J, Butler PF, Callah an MJ, Coley BD, Farley S, Frush DP, 4151 Hernanz-Schulman M, Jaramillo D and others. 2008. T he Image Gently campaign: 4152 working together to change practice. AJR Am J Roent genol 190(2):273-274. 4153 Gray JE, Archer BR, Butler PF, Hobbs BB, Mettler FA , Jr., Pizzutiello RJ, Jr., Schueler BA, 4154 Strauss KJ, Suleiman OH, Yaffe MJ. 2005. Reference values for diagnostic radiology: 4155 application and impact. Radiology 235(2):354-8. 4156 Harrison JD, Streffer C. 2007. The ICRP protection quantities, equivalent and effective dose: 4157 their basis and application. Radiat Prot Dosimetry 127(1-4):12-8. 4158 Hart D, Hillier MC, Wall BF. 2009. National referen ce doses for common radiographic, 4159 fluoroscopic and dental X-ray examinations in the U K. Br J Radiol 82(973):1-12. 4160 Hirshfeld JW, Jr., Balter S, Brinker JA, Kern MJ, K lein LW, Lindsay BD, Tommaso CL, Tracy 4161 CM, Wagner LK. 2004. ACCF/AHA/HRS/SCAI clinical com petence statement on 4162 physician knowledge to optimize patient safety and image quality in fluoroscopically 4163 guided invasive cardiovascular procedures: a report of the American College of 4164 Cardiology Foundation/American Heart Association/Am erican College of Physicians 4165 Task Force on Clinical Competence and Training. Jou rnal of the American College of 4166 Cardiology 44(11):2259-2282. 4167 IAEA. 1996. Safety Series No. 115: International ba sic safety standards for protection against 4168 ionizing raidiation and the safety of radiation sou rces. Vienna: International Atomic 4169 Energy Agency. 4170REF-5

IAEA. 2009. Establishing guidance levels in x ray g uided medical interventional procedures: A 4171 pilot study. Safety Reports Series No. 59. Vienna: International Atomic Energy Agency. 4172

IAEA. 2011a. IAEA SAFETY STANDARDS SERIES No. GSR P art 3 (Interim): Radiation 4173 protection and safety of radiation sources - Intern ational Basic Safety Standards. Vienna: 4174 International Atomic Energy Agency. 4175 IAEA. 2011b. IAEA Safety Standards: Radiation Prote ction and Safety of Radiation Sources - 4176 IARC. 2012. Agents Classified by the IARC Monograph s, Volumes 1–105. Lyon: International 4177 Agency for Research on Cancer, World Health Organiz ation. 4178

ICRP. 1991a. ICRP Publication No. 60: 1990 Recommen dations of the International 4179 Commission on Radiological Protection. Internationa l Commission on Radiological 4180 Protection. Annals of the ICRP 21(1-3):1-201. 4181 ICRP. 1991b. ICRP Publication No. 62: Radiological protection in biomedical research : A 4182 report of Committee 3 adopted by the International Commission on Radiological 4183 Protection. International Commission on Radiologica l Protection. Ann ICRP 22(3). 4184 ICRP. 1996. ICRP Publication No. 73: Radiologcal pr otection and safety in medicine. Oxford: 4185 Pergamon Press. 4186

ICRP. 2000a. ICRP Publication No. 85: Avoidance of radiation injuries from medical 4187 interventional procedures. International Commission on Radiological Protection. Annals 4188 of the ICRP 30(2):7-67. 4189 ICRP. 2000b. ICRP Publication No. 87: Managing pati ent dose in computed tomography. 4190 Oxford: Pergamon Press. 4191 ICRP. 2003. Diagnostic reference levels in medical imaging: review and additional advice. 4192

ICRP online educational reference.: International C ommission on Radiological 4193

Protection. 4194 ICRP. 2004. ICRP Publication No. 93: Manating patie nt dose in digital radiology. International 4195 Commission on Radiological Protection. Ann ICRP. Ox ford: Pergamon Press. 4196

ICRP. 2007a. ICRP Publication No. 103: The 2007 Rec ommendations of the International 4197 Commission on Radiological Protection. Internationa l Commission on Radiological 4198 Protection. Ann ICRP 37(2-4):1-332. 4199

ICRP. 2007b. ICRP Publication No. 103: The 2007 Rec ommendations of the International 4200 Commission on Radiological Protection.: Internation al Commission on Radiological 4201 Protection. 1-332 p. 4202 ICRP. 2007c. ICRP Publication No. 105: Radiation pr otection in medicine. International 4203 Commission on Radiological Protection. Ann ICRP 37( 6):1-63. 4204 ICRP. 2012. ICRP Publication No. 120: Radiological Protection in Cardiology. Ann ICRP 41(3). 4205 ICRU. 2005, or most current version. ICRU Report 74 : Patient dosimetry for X rays used in 4206 medical imaging. International Commission on Radiat ion Units & Measurements. Journal 4207 of the ICRU 5(2):1-113. 4208 IEC. 2008. IEC Report 62494-1: Medical electrical e quipment - Exposure index of digital x-ray 4209 imaging systems - Part 1: Definitiona and requireme nts for general radiography. 4210

International Electrotechnical Commission. 4211 IEC. 2010. IEC Report 60601: Medical electrical equ ipment - Part 2-43: Particular requirements 4212 for the safety of X-ray equipment for interventiona l procedures. Geneva, Switzerland: 4213 International Electrotechnical Commission. Report n r 60601-2-43. 4214REF-6

IHE. 2008. IHE Radiology Technical Framework Supple ment 2007-2008 (public comment 4215 draft): Radiation exposure monitoring (REM) integra tion profile. Integrating the 4216 Healthcare Enterprise. 4217 ISCD. 2007a. Official positions of the Internationa l Society for Clinical Densitometry. West 4218 Hartford, CT: International Society for Clinical De nsitometry. 4219

ISCD. 2007b. Pediatric Official Positions of the In ternational Society for Clinical Densitometry. 4220 W. Hartford, CT: International Society for Clinical Densitometry. 4221 ISCD. 2012. ISCD home page. International Society f or Clinical Densitometry. 4222 Kanis JA, Melton LJ, 3rd, Christiansen C, Johnston CC, Khaltaev N. 1994. The diagnosis of 4223 osteoporosis. Journal of Bone and Mineral Research 9(8):1137-41. 4224 Kwon D, Little MP, Miller DL. 2011. Reference air k erma and kerma-area product as estimators 4225 of peak skin dose for fluoroscopically guided inter ventions. Medical Physics 38(7):4196- 4226

204. 4227 Lipsitz EC, Veith FJ, Ohki T, Heller S, Wain RA, Su ggs WD, Lee JC, Kwei S, Goldstein K, 4228 Rabin J and others. 2000. Does the endovascular rep air of aortoiliac aneurysms pose a 4229 radiation safety hazard to vascular surgeons? Journ al of Vascular Surgery 32(4):704-710. 4230 MacDonald JC, Reid JA, Berthoty D. 1983. Drywall co nstruction as a dental radiation barrier. 4231 Oral Surgery, Oral Medicine, Oral Pathology 55(3):3 19-26. 4232 Mahesh M. 2008. How to prepare for the Joint Commis sion's sentinel event policy pertaining to 4233 prolonged fluoroscopy. J Am Coll Radiol 5(4):601-3. 4234

Martin CJ. 2007. Effective dose: how should it be a pplied to medical exposures? Br J Radiol 4235 80(956):639-47. 4236 Masih S, Morrison L, Massoth R, Taylor T, Maxwell P . 2006. Working with a Hand-Held Dental 4237 X-Ray Unit : Equipment Evaluation. 4238 McCollough CH. 2008. CT dose: how to measure, how t o reduce. Health Phys 95(5):508-17. 4239 McNitt-Gray MF. 2002. AAPM/RSNA Physics Tutorial fo r Residents: Topics in CT. Radiation 4240 dose in CT. Radiographics 22(6):1541-53. 4241 Mettler FA, Jr., Huda W, Yoshizumi TT, Mahesh M. 20 08. Effective doses in radiology and 4242 diagnostic nuclear medicine: a catalog. Radiology 2 48(1):254-63. 4243 Miles DA, Van Dis ML, Peterson MG. 1989. Informatio n yield: a comparison of Kodak T-Mat 4244 G, Ortho L and RP X-Omat films. Dento-Maxillo-Facia l Radiology 18(1):15-8. 4245 Miller DL. 2008. Overview of contemporary intervent ional fluoroscopy procedures. Health Phys 4246 95(5):638-44. 4247 Miller DL, Balter S, Cole PE, Lu HT, Berenstein A, Albert R, Schueler BA, Georgia JD, Noonan 4248 PT, Russell E and others. 2003a. Radiation doses in interventional radiology procedures: 4249 The RAD-IR study Part II. Skin dose. Journal of Vas cular and Interventional Radiology 4250 14(8):977-990. 4251 Miller DL, Balter S, Cole PE, Lu HT, Schueler BA, G eisinger M, Berenstein A, Albert R, 4252 Georgia JD, Noonan PT and others. 2003b. Radiation doses in interventional radiology 4253 procedures: The RAD-IR study Part I. Overall measur es of dose. Journal of Vascular and 4254 Interventional Radiology 14(6):711-727. 4255 Miller DL, Balter S, Dixon RG, Nikolic B, Bartal G, Cardella JF, Dauer LT, Stecker MS. 2012. 4256 Quality improvement guidelines for recording patien t radiation dose in the medical 4257 record for fluoroscopically guided procedures. Jour nal of Vascular and Interventional 4258 Radiology 23(1):11-8. 4259REF-7

Miller DL, Balter S, Noonan PT, Georgia JD. 2002. M inimizing radiation-induced skin injury in 4260 interventional radiology procedures. Radiology 225( 2):329-336. 4261 Miller DL, Balter S, Schueler BA, Wagner LK, Straus s KJ, Vano E. 2010a. Clinical radiation 4262 management for fluoroscopically guided intervention al procedures. Radiology 4263 257(2):321-32. 4264 Miller DL, Balter S, Wagner LK, Cardella JF, Clark TWI, Neithamer CD, Jr., Schwartzberg MS, 4265 Swan TL, Towbin RB, Rholl KS and others. 2004. Qual ity improvement guidelines for 4266 recording patient radiation dose in the medical rec ord. J Vasc Interv Radio 15(5):423- 4267

429. 4268 Miller DL, Kwon D, Bonavia GH. 2009. Reference leve ls for patient radiation doses in 4269 interventional radiology: proposed initial values f or U.S. practice. Radiology 253(3):753- 4270

764. 4271 Miller DL, Vano E, Bartal G, Balter S, Dixon R, Pad ovani R, Schueler B, Cardella JF, de Baere 4272 T. 2010b. Occupational radiation protection in inte rventional radiology: A joint guideline 4273 of the Cardiovascular and Interventional Radiology Society of Europe and the Society of 4274 Interventional Radiology. Cardiovasc Intervent Radi ol 33(2):230-9. 4275 NCRP. 1988. NCRP Report No. 99: Quality assurance f or diagnostic imaging. Bethesda, MD: 4276

National Council on Radiation Protection and Measur ements. 4277 NCRP. 1989a. NCRP Report No. 100: Exposure of the U .S. population from diagnostic medical 4278 radiation. Bethesda, MD: National Council on Radiat ion Protection and Measurements. 4279 NCRP. 1989b. NCRP Report No. 102: Medical X-ray, El ectron Beam and Gamma-ray 4280 Protection for Energies Up to 50 MeV (Equipment Des ign, Performance, and Use 4281 (Supersedes NCRP Report No. 33). . Bethesda, MD. 4282 NCRP. 1990. NCRP Report No. 107: Implementation of the principle of ALARA for medical 4283 and dental personnel. Bethesda, MD: National Counci l on Radiation Protection and 4284

Measurements. 4285 NCRP. 1995. NCRP Report No. 122: Use of personal mo nitors to estimate effective dose 4286 equivalent and effective dose to workers for extern al exposure to low-LET radiation. 4287 Bethesda, MD: National Council on Radiation Protect ion and Measurements. 4288 NCRP. 2000. NCRP Report No. 133: Radiation protecti on for procedures performed outside the 4289 radiology department. Bethesda, MD: National Counci l on Radiation Protection and 4290

Measurements. 4291 NCRP. 2003. NRCP Report No. 145: Radiation protecti on in dentistry. Bethesda, MD: National 4292

Council on Radiation Protection and Measurements. 4293 NCRP. 2004a. NCRP Report No. 147: Structural shield ing design for medical x-ray imaging 4294 facilities. Bethesda, MD: National Council on Radia tion Protection and Measurements. 4295 NCRP. 2004b. NCRP Report No. 148: Radiation protect ion in veterinary medicine. Bethesda, 4296

MD: National Council on Radiation Protection and Me asurements. 4297 NCRP. 2009. NCRP Report No. 160: Ionizing radiation exposure of the population of the United 4298 States. Bethesda, MD: National Council on Radiation Protection and Measurements. 4299 NCRP. 2010. NCRP Report No. 168: Radiation dose man agement for fluoroscopically guided 4300 interventional medical procedures. Bethesda, MD: Na tional Council on Radiation 4301

Protection and Measurements. 4302 NEMA. 2009. NEMA PS 3.14: Digital Imaging and Commu nications in Medicine (DICOM) 4303 Part 14: Grayscale Standard Display Function. In: A ssociation NEM, editor. 4304REF-8

Neofotistou V, Vano E, Padovani R, Kotre J, Dowling A, Toivonen M, Kottou S, Tsapaki V, 4305 Willis S, Bernardi G and others. 2003. Preliminary reference levels in interventional 4306 cardiology. Eur Radiol 13(10):2259-63. 4307 NHS. 1993. What do we mean by appropriate health ca re? Report of a working group prepared 4308 for the Director of Research and Development of 4309 the NHS Management Executive, National Health Servi ce. Quality in Health Care 2(2):117-123. 4310 NIH. 2001. Improving informed consent for research radiation studies. National Institutes of 4311

Health. 4312 NIH. 2008a. Informed consent template B: Radiation exposure consent language (less than 5 rem 4313 effective dose) 4314 NIH. 2008b. Informed consent template C: Total effe ctive dose > 5 rem. In: Health NIo, editor. 4315 NIH. 2010. Informed Consent Template A: Total effec tive dose less than or equal to 0.3 rem. 4316

National Institutes of Health. 4317

NIH NCI SIR. 2005. NIH Publication No. 05-5286: Int erventional Fluoroscopy: Reducing 4318

Radiation Risks for Patients and Staff. National In stitutes of Health, National Cancer 4319 Institute and The Society of Interventional Radiolo gy. 4320 NRPB. 1990. Patient dose reduction in diagnostic ra diology: Report by the Royal College of 4321 Radiologists and the National Radiological Protecti on Board. London: National Radiation 4322 Protection Board. 1-46 p. 4323 NTP. 2011. Twelfth Report on Carcinogens. Departmen t of Health and Human Services, 4324 National Toxicology Program. 4325 O'Dea TJ, Geise RA, Ritenour ER. 1999. The potentia l for radiation-induced skin damage in 4326 interventional neuroradiological procedures: a revi ew of 522 cases using automated 4327 dosimetry. Med Phys 26(9):2027-33. 4328 Orth RC, Wallace MJ, Kuo MD. 2008. C-arm Cone-beam CT: General Principles and Technical 4329 Considerations for Use in Interventional Radiology. Journal of Vascular and 4330 Interventional Radiology 19(6):814-20. 4331 OSHA. 2012. 29CFR1910.1096: Ionizing radiation. In: Administration OSH, editor. Title 29 4332 Code of Federal Regulations Part 1910.1096. 4333 OSTP, USDA, DOE, NASA, DOC, CPSC, IDCAAID, HUD, DOJ , DoD and others. 1991. 4334 56FR28002-28032: Federal policy for the protection of human subjects. In: rule Mc, 4335 editor: Federal Register. p 28002-28032. 4336 Padovani R, Quai E. 2005. Patient dosimetry approac hes in interventional cardiology and 4337 literature dose data review. Radiat Prot Dosimetry 117(1-3):217-221. 4338 Paterson A, Frush DP, Donnelly LF. 2001. Helical CT of the body: are settings adjusted for 4339 pediatric patients? AJR. American Journal of Roentg enology 176(2):297-301. 4340 Peterzol A, Quai E, Padovani R, Bernardi G, Kotre C J, Dowling A. 2005. Reference levels in 4341 PTCA as a function of procedure complexity. Radiati on Protection Dosimetry 117(1- 4342 3):54-58. 4343 Scarfe WC, Farman AG, Sukovic P. 2006. Clinical app lications of cone-beam computed 4344 tomography in dental practice. Journal / Canadian D ental Association. Journal de l 4345 Association Dentaire Canadienne 72(1):75-80. 4346 Seibert JA, Shelton DK, Moore EH. 1996. Computed ra diography X-ray exposure trends. 4347 Academic Radiology 3(4):313-8. 4348 Sidhu MK, Goske MJ, Coley BJ, Connolly B, Racadio J , Yoshizumi TT, Utley T, Strauss KJ. 4349 2009. Image gently, step lightly: increasing radiat ion dose awareness in pediatric 4350REF-9

interventions through an international social marke ting campaign. J Vasc Interv Radiol 4351 20(9):1115-9. 4352 Sistrom CL. 2008. In support of the ACR Appropriate ness Criteria®. Journal of the American 4353 College of Radiology 5(5):630-5; discussion 636-7. 4354 Smith-Bindman R, Lipson J, Marcus R, Kim KP, Mahesh M, Gould R, Berrington de Gonzalez 4355 A, Miglioretti DL. 2009. Radiation dose associated with common computed tomography 4356

examinations and the associated lifetime attributab le risk of cancer. Arch Intern Med 4357 169(22):2078-86. 4358 Stecker MS, Balter S, Towbin RB, Miller DL, Vañó E, Bartal G, Angle JF, Chao CP, Cohen 4359 AM, Dixon RG and others. 2009. Guidelines for patie nt radiation dose management. J 4360 Vasc Interv Radiol 20(7S):S263-S273. 4361 Stedman. 2006. Stedman's Medical Dictionary. In: Wi lkins LW, editor. 28th ed. 4362 Steele JR, Jones AK, Ninan EP. 2012. Quality initia tives: Establishing an interventional 4363 radiology patient radiation safety program. Radiogr aphics 32(1):277-87. 4364 Strauss KJ, Goske MJ, Kaste SC, Bulas D, Frush DP, Butler P, Morrison G, Callahan MJ, 4365 Applegate KE. 2010. Image gently: Ten steps you can take to optimize image quality and 4366 lower CT dose for pediatric patients. AJR Am J Roen tgenol 194(4):868-73. 4367 Suzuki S, Furui S, Kohtake H, Yokoyama N, Kozuma K, Yamamoto Y, Isshiki T. 2006. 4368 Radiation exposure to patient's skin during percuta neous coronary intervention for 4369 various lesions, including chronic total occlusion. Circ.J. 70:44-48. 4370

The Joint Commission. 2006. Sentinel event: Radiati on overdose FAQs. 4371 The Joint Commission. 2012a. Accreditation Program: Hospital National Patient Safety Goals. 4372 In: Commission TJ, editor. p 11-13. 4373

The Joint Commission. 2012b. Universal Protocol web page. The Joint Commission. 4374 Tsalafoutas IA, Goni H, Maniatis PN, Pappas P, Bouz as N, Tzortzis G. 2006. Patient doses from 4375 noncardiac diagnostic and therapeutic interventiona l procedures. Journal of Vascular and 4376 Interventional Radiology 17(9):1489-98. 4377

USNRC. 2012a. 10CFR20.1003: Definitions. In: Commis sion NR, editor. Title 10 Code of 4378 Federal Regulations Part 20.1003. 4379 USNRC. 2012b. 10CFR20.1208: Dose equivalent to an e mbryo/fetus. In: Commission NR, 4380 editor. Title 10 Code of Federal Regulations Part 2 0.1208. 4381 USNRC. 2012c. 10CFR20: Standards for protection aga inst radiation. In: Commission NR, 4382 editor. Title 10 Code of Federal Regulations Part 2 0. 4383

USNRC. 2012d. 10CFR35: Medical use of radioactive m aterial. In: Commission UNR, editor. 4384 Vano E. 2003. Radiation exposure to cardiologists: how it could be reduced. Heart 89(10):1123- 4385

4. 4386 Vañó E, Gonzalez L. 2001. Approaches to establishin g reference levels in interventional 4387 radiology. Radiat Prot Dosimetry 94(1-2):109-112. 4388 Vano E, Järvinen H, Kosunen A, Bly R, Malone J, Dow ling A, Larkin A, Padovani R, Bosmans 4389 H, Dragusin O and others. 2008a. Patient dose in in terventional radiology: a European 4390 survey. Radiat Prot Dosimetry 129(1-3):39-45. 4391 Vano E, Sanchez R, Fernandez JM, Gallego JJ, Verdu JF, de Garay MG, Azpiazu A, Segarra A, 4392 Hernandez MT, Canis M and others. 2009. Patient dos e reference levels for 4393 interventional radiology: a national approach. Card iovasc Intervent Radiol 32(1):19-24. 4394REF-10

Vano E, Segarra A, Fernandez JM, Ordiales JM, Simon R, Gallego JJ, Del Cerro J, Casasola E, 4395 Verdu JF, Ballester T and others. 2008b. A pilot ex perience launching a national dose 4396 protocol for vascular and interventional radiology. Radiat Prot Dosimetry 129(1-3):46-9. 4397 Verdun FR, Aroua A, Trueb PR, Vock P, Valley JF. 20 05. Diagnostic and interventional 4398 radiology: a strategy to introduce reference dose l evel taking into account the national 4399 practice. Radiat Prot Dosimetry 114(1-3):188-91. 4400 Wagner LK, Archer BR, Cohen AM. 2000. Management of patient skin dose in fluoroscopically 4401 guided interventional procedures. Journal of Vascul ar and Interventional Radiology 4402 11(1):25-33. 4403 Wall BF. 2001. Diagnostic reference levels--the way forward. Br J Radiol 74(885):785-8. 4404 Wall BF, Shrimpton PC. 1998. The historical develop ment of reference doses in diagnostic 4405 radiology. Radiat Prot Dosimetry 80(1-3):15-19. 4406 Wallace MJ, Kuo MD, Glaiberman C, Binkert CA, Orth RC, Soulez G. 2008. Three4407 Dimensional C-arm Cone-beam CT: Applications in the Interventional Suite. Journal of 4408 Vascular and Interventional Radiology 19(6):799-813

. 4409 WHO. 2004. WHO Scientific Group on the Assessment o f Osteoporosis at Primary Health Care 4410 Level, Summary meeting report, Brussels, Belgium 5- 7 May 2004. Geneva: World 4411 Health Organization. 4412

WHO. 2012. WHO fracture risk assessment tool. Unive rsity of Sheffield, UK World Health 4413 Organization Collaborating Centre for Metabolic Bon e Diseases. 4414 Willis CE, Slovis TL. 2005. The ALARA concept in pe diatric CR and DR: dose reduction in 4415 pediatric radiographic exams--a white paper confere nce. AJR. American Journal of 4416 Roentgenology 184(2):373-4. 4417 Witzel J. 2008. Operational and radiation safety gu idelines for hand held intraoral x-ray systems 4418 - A thesis. San Antonio, TX: The University of Texa s Health Science Center at San 4419 Antonio. 47 p. 4420

4421

4422