bluuebunny/crossref_metadata_2025 huggingface dataset:
MO‐DE‐BRA‐04: Hands‐On Fluoroscopy Safety Training with Real‐Time Patient and Staff Dosimetry
Authors: Vanderhoek M , Bevins N
Published: July 2016

Purpose:

Fluoroscopically guided interventions (FGI) are routinely performed across many different hospital departments. However, many involved staff members have minimal training regarding safe and optimal use of fluoroscopy systems. We developed and taught a hands‐on fluoroscopy safety class incorporating real‐time patient and staff dosimetry in order to promote safer and more optimal use of fluoroscopy during FGI.

Methods:

The hands‐on fluoroscopy safety class is taught in an FGI suite, unique to each department. A patient equivalent phantom is set on the patient table with an ion chamber positioned at the x‐ray beam entrance to the phantom. This provides a surrogate measure of patient entrance dose. Multiple solid state dosimeters (RaySafe i2 dosimetry systemTM) are deployed at different distances from the phantom (0.1, 1, 3 meters), which provide surrogate measures of staff dose. Instructors direct participating clinical staff to operate the fluoroscopy system as they view live fluoroscopic images, patient entrance dose, and staff doses in real‐time. During class, instructors work with clinical staff to investigate how patient entrance dose, staff doses, and image quality are affected by different parameters, including pulse rate, magnification, collimation, beam angulation, imaging mode, system geometry, distance, and shielding.

Results:

Real‐time dose visualization enables clinical staff to directly see and learn how to optimize their use of their own fluoroscopy system to minimize patient and staff dose, yet maintain sufficient image quality for FGI. As a direct result of the class, multiple hospital departments have implemented changes to their imaging protocols, including reduction of the default fluoroscopy pulse rate and increased use of collimation and lower dose fluoroscopy modes.

Conclusion:

Hands‐on fluoroscopy safety training substantially benefits from real‐time patient and staff dosimetry incorporated into the class. Real‐time dose display helps clinical staff visualize, internalize, and ultimately utilize the safety techniques learned during the training.

RaySafe/Unfors/Fluke lent us a portable version of their RaySafe i2 Dosimetry System for 6 months.
TU‐D‐204‐02: The Linear No‐Threshold Model (LNT): Made to Be Tested, Made to Be Questioned
Authors: Miller R.
Published: July 2016

Making of the Atomic Bomb

2015 is the 70th anniversary of the detonation of the first atomic bomb. Since then, few scientific issues have aroused so much public controversy as the effects of radiation. This lecture will present the extraordinary historical genesis and the thoughts of great men and women in the development of the atomic bomb. In addition, the difficult military and political decisions will be covered such as: target selection, the debate over whether to give the Japanese government a demonstration of its power and whether to use it at all. Also, were the German and Japanese scientists developing there own bomb? Declassified top secret documents now help in answering some of these questions.
TU‐D‐201‐03: Results of a Survey On the Implementation of the TG‐51 Protocol and Associated Addendum On Reference Dosimetry of External Beams
Authors: Kim G , Muir B , Culberson W , Davis S , Huang Y , Lee S , Lowenstein J , Sarfehnia A , Tolani N , Siebers J
Published: July 2016

Purpose:

The working group on the review and extension of the TG‐51 protocol (WGTG51) collected data from American Association of Physicists in Medicine (AAPM) members with respect to their current TG‐51 and associated addendum usage in the interest of considering future protocol addenda and guidance on reference dosimetry best practices. This study reports an overview of this survey on dosimetry of external beams.

Methods:

Fourteen survey questions were developed by WGTG51 and released in November 2015. The questions collected information on reference dosimetry, beam quality specification, and ancillary calibration equipment.

Results:

Of the 190 submissions completed worldwide (U.S. 70%), 83% were AAPM members. Of the respondents, 33.5% implemented the TG‐51 addendum, with the maximum calibration difference for any photon beam, with respect to the original TG‐51 protocol, being <1% for 97.4% of responses. One major finding is that 81.8% of respondents used the same cylindrical ionization chamber for photon and electron dosimetry, implying that many clinics are foregoing the use of parallel‐plate chambers. Other evidence suggests equivalent dosimetric results can be obtained with both cylindrical and parallel‐plate chambers in electron beams. This, combined with users comfort with cylindrical chambers for electrons will likely impact recommendations put forward in an upcoming electron beam addendum to the TG‐51 protocol. Data collected on ancillary equipment showed 58.2% (45.0%) of the thermometers (barometers) in use for beam calibration had NIST traceable calibration certificates, but 48.4% (42.7%) were never recalibrated.

Conclusion:

This survey provides a snapshot of TG‐51 external beam reference dosimetry practice in radiotherapy centers. Findings demonstrate the rapid take‐up of the TG‐51 photon beam addendum and raise issues for the WGTG51 to focus on going forward, including guidelines on ancillary equipment and the choice of chamber for electron beam dosimetry.
TU‐D‐201‐07: Severity Indication in High Dose Rate Brachytherapy Emergency Response Procedure
Authors: Li K , Rustad F
Published: July 2016

Purpose:

Understanding the corresponding dose to different staff during the High Dose Rate (HDR) Brachytherapy emergency response procedure could help to develop a strategy in efficiency and effective action. In this study, the variation and risk analysis methodology was developed to simulation the HDR emergency response procedure based on severity indicator.

Methods:

A GammaMedplus iX HDR unit from Varian Medical System was used for this simulation. The emergency response procedure was decomposed based on risk management methods. Severity indexes were used to identify the impact of a risk occurrence on the step including dose to patient and dose to operation staff by varying the time, HDR source activity, distance from the source to patient and staff and the actions. These actions in 7 steps were to press the interrupt button, press emergency shutoff switch, press emergency button on the afterloader keypad, turn emergency hand‐crank, remove applicator from the patient, disconnect transfer tube and move afterloader from the patient, and execute emergency surgical recovery.

Results:

Given the accumulated time in second at the assumed 7 steps were 15, 5, 30, 15, 180, 120, 1800, and the dose rate of HDR source is 10 Ci, the accumulated dose in cGy to patient at 1cm distance were 188, 250, 625, 813, 3063, 4563 and 27063, and the accumulated exposure in rem to operator at outside the vault, 1m and 10cm distance were 0.0, 0.0, 0.1, 0.1, 22.6, 37.6 and 262.6. The variation was determined by the operators in action at different time and distance from the HDR source.

Conclusion:

The time and dose were estimated for a HDR unit emergency response procedure. It provided information in making optimal decision during the emergency procedure. Further investigation would be to optimize and standardize the responses for other emergency procedure by time‐spatial‐dose severity function.
TU‐D‐BRC‐02: Free Information ‐ EPID‐Based In Vivo Dosimetry
Authors: Greer P.
Published: July 2016

There has been increased deployment of gantry‐mounted linacs with onboard kilovoltage x‐ray imagers. Despite this trend, most clinics still employ beam's‐eye‐view (BEV) imaging using flat panel electronic portal imaging devices (EPIDs) as a highly useful means of verifying geometric localization pre‐ and post‐delivery. In recent years, there has been increased interest in the use of EPIDs for a variety of clinical and investigational applications ranging from megavoltage cone‐beam CT, in vivo dosimetry, patient‐specific QA to real‐time target localization for dynamic MLC‐based tumor tracking. In conjunction, there are several innovative EPID designs currently under investigation that hold great promise in bringing novel imaging and image‐guidance applications into clinical practice.

This symposium is aimed at clinical and research‐oriented medical physicists who want to learn more about current and future megavoltage imaging technology and applications. In this symposium, we will examine the (i) interesting applications that make use of current EPID technology such as volumetric 4D image‐based models, real‐time position estimation for dynamic MLC tracking, etc., (ii) clinical applications such as in vivo EPID dosimetry and (iii) innovative high‐performance EPID designs and exciting future applications, including designs based on thick segmented scintillators, hybrid kV/MV imagers using segmented strip scintillators, and energy‐resolving EPIDs based on multilayer imagers and poly‐Silicon active matrix flat panel imagers.

Learning Objectives – In this symposium, the attendees will learn

Novel applications using currently available EPIDs

Use of EPIDs to perform in vivo dosimetry

Novel designs using high‐efficiency, energy resolving EPIDs and future applications of megavoltage imaging

J. Rottmann, Varian Medical SystemsP. Greer, Research Grant Funding from Radiation Oncology Institute (Grant ROI2013‐912), 2013–2014
TU‐D‐BRB‐00: Dual Energy CT in Radiation Therapy
Authors: Labby Zacariah
Published: July 2016

Dual‐energy CT technology is becoming increasingly available to the medical imaging community. In addition, several models of CT simulators sold for use in radiation therapy departments now feature dual‐energy technology. The images provided by dual‐energy CT scanners add new information to the radiation treatment planning process; multiple spectral components can be used to separate and identify material composition as well as generate virtual monoenergetic images. In turn, this information could be used to investigate pathologic processes, separate the properties of contrast agents from soft tissues, assess tissue response to therapy, and other applications of therapeutic interest. Additionally, the decomposition of materials in images could directly integrate with and impact the accuracy of dose calculation algorithms.

This symposium will explore methods of generating dual‐energy CT images, spectral and image analysis algorithms, current and future applications of interest in oncologic imaging, and unique considerations when using dualenergy CT images in the radiation treatment planning process.

Learning Objectives:

Understand acquisition techniques and processing algorithms used in dual‐energy CT imaging.

Discover current and future applications of dual‐energy CT images in the radiological oncology setting.

Introduce some of the unique considerations and QA requirements when integrating a dual‐energy CT scanner into the radiation therapy environment.

N. Pelc: GE Healthcare, Philips Healthcare, Sony; U. Schoepf: Consultant for and / or research support from Astellas, Bayer,;Bracco, GE, Guerbet, Medrad, Siemens
TU‐D‐BRB‐01: Dual‐Energy CT: Techniques in Acquisition and Image Processing
Authors: Pelc N.
Published: July 2016

Dual‐energy CT technology is becoming increasingly available to the medical imaging community. In addition, several models of CT simulators sold for use in radiation therapy departments now feature dual‐energy technology. The images provided by dual‐energy CT scanners add new information to the radiation treatment planning process; multiple spectral components can be used to separate and identify material composition as well as generate virtual monoenergetic images. In turn, this information could be used to investigate pathologic processes, separate the properties of contrast agents from soft tissues, assess tissue response to therapy, and other applications of therapeutic interest. Additionally, the decomposition of materials in images could directly integrate with and impact the accuracy of dose calculation algorithms.

This symposium will explore methods of generating dual‐energy CT images, spectral and image analysis algorithms, current and future applications of interest in oncologic imaging, and unique considerations when using dualenergy CT images in the radiation treatment planning process.

Learning Objectives:

Understand acquisition techniques and processing algorithms used in dual‐energy CT imaging.

Discover current and future applications of dual‐energy CT images in the radiological oncology setting.

Introduce some of the unique considerations and QA requirements when integrating a dual‐energy CT scanner into the radiation therapy environment.

N. Pelc: GE Healthcare, Philips Healthcare, Sony; U. Schoepf: Consultant for and / or research support from Astellas, Bayer,;Bracco, GE, Guerbet, Medrad, Siemens
TU‐D‐206‐01: Body Tomosynthesis Introduction
Authors: Bath M.
Published: July 2016

The current use of tomosynthesis for musculo‐skeletal, abdominal, and thoracic imaging will be considered in four sections:

A. Current Practice (M. Bath) : The presently available systems for body tomosynthesis will be reviewed and the current diagnostic applications described.

B. Image Features and artifacts (M. FLynn): The consequence of a limited angle linear acquisition scan on image features and artifacts will be explained.

C. Radiation Dose (J. Sabol): The organ dose associated with common tomosynthesis protocols will be reported and compared to the dose for radiographic and computed tomography procedures.

D. Acceptance testing and Quality Assurance (K. Jones): Recommended medical physics acceptance test will be described and appriate programs for quality assurance discussed.

Learning Objectives:

Learn how body tomosynthesis is currently being used in diagnostic radiology.

Understand how scan acquisitions can be designed to optimize image content and minimize artifacts.

Learn to radiation dose associated with common protocols.

Understand how to best evaluate a newly purchased tomosynthesis system.

J. Sabol, Presenter is an employee of GE Healthcare.
TU‐D‐206‐03: TS Body Dose
Authors: Sabol J.
Published: July 2016

The current use of tomosynthesis for musculo‐skeletal, abdominal, and thoracic imaging will be considered in four sections:

A. Current Practice (M. Bath) : The presently available systems for body tomosynthesis will be reviewed and the current diagnostic applications described.

B. Image Features and artifacts (M. FLynn): The consequence of a limited angle linear acquisition scan on image features and artifacts will be explained.

C. Radiation Dose (J. Sabol): The organ dose associated with common tomosynthesis protocols will be reported and compared to the dose for radiographic and computed tomography procedures.

D. Acceptance testing and Quality Assurance (K. Jones): Recommended medical physics acceptance test will be described and appriate programs for quality assurance discussed.

Learning Objectives:

Learn how body tomosynthesis is currently being used in diagnostic radiology.

Understand how scan acquisitions can be designed to optimize image content and minimize artifacts.

Learn to radiation dose associated with common protocols.

Understand how to best evaluate a newly purchased tomosynthesis system.

J. Sabol, Presenter is an employee of GE Healthcare.
TU‐D‐209‐02: A Backscatter Point Spread Function for Entrance Skin Dose Determination
Authors: Vijayan S , Xiong Z , Shankar A , Rudin S , Bednarek D
Published: July 2016

Purpose:

To determine the distribution of backscattered radiation to the skin resulting from a non‐uniform distribution of primary radiation through convolution with a backscatter point spread function (PSF).

Methods:

A backscatter PSF is determined using Monte Carlo simulation of a 1 mm primary beam incident on a 30 × 30 cm × 20 cm thick PMMA phantom using EGSnrc software. A primary profile is similarly obtained without the phantom and the difference from the total provides the backscatter profile. This scatter PSF characterizes the backscatter spread for a “point” primary interaction and can be convolved with the entrance primary dose distribution to obtain the total entrance skin dose. The backscatter PSF was integrated into the skin dose tracking system (DTS), a graphical utility for displaying the color‐coded skin dose distribution on a 3D graphic of the patient during interventional fluoroscopic procedures. The backscatter convolution method was validated for the non‐uniform beam resulting from the use of an ROI attenuator. The ROI attenuator is a copper sheet with about 20% primary transmission (0.7 mm thick) containing a circular aperture; this attenuator is placed in the beam to reduce dose in the periphery while maintaining full dose in the region of interest. The DTS calculated primary plus backscatter distribution is compared to that measured with GafChromic film and that calculated using EGSnrc Monte‐Carlo software.

Results:

The PSF convolution method used in the DTS software was able to account for the spread of backscatter from the ROI region to the region under the attenuator. The skin dose distribution determined using DTS with the ROI attenuator was in good agreement with the distributions measured with Gafchromic film and determined by Monte Carlo simulation

Conclusion:

The PSF convolution technique provides an accurate alternative for entrance skin dose determination with non‐uniform primary x‐ray beams.

Partial support from NIH Grant R01‐EB002873 and Toshiba Medical Systems Corp.
TU‐D‐209‐05: Automatic Calculation of Organ and Effective Dose for CBCT and Interventional Fluoroscopic Procedures
Authors: Xiong Z , Vijayan S , Oines A , Rudin S , Bednarek D
Published: July 2016

Purpose:

To compare PCXMC and EGSnrc calculated organ and effective radiation doses from cone‐beam computed tomography (CBCT) and interventional fluoroscopically‐guided procedures using automatic exposure‐event grouping.

Methods:

For CBCT, we used PCXMC20Rotation.exe to automatically calculate the doses and compared the results to those calculated using EGSnrc with the Zubal patient phantom. For interventional procedures, we use the dose tracking system (DTS) which we previously developed to produce a log file of all geometry and exposure parameters for every x‐ray pulse during a procedure, and the data in the log file is input into PCXMC and EGSnrc for dose calculation. A MATLAB program reads data from the log files and groups similar exposures to reduce calculation time. The definition files are then automatically generated in the format used by PCXMC and EGSnrc. Processing is done at the end of the procedure after all exposures are completed.

Results:

For the Toshiba Infinix CBCT LCI‐Middle‐Abdominal protocol, most organ doses calculated with PCXMC20Rotation closely matched those calculated with EGSnrc. The effective doses were 33.77 mSv with PCXMC20Rotation and 32.46 mSv with EGSnrc. For a simulated interventional cardiac procedure, similar close agreement in organ dose was obtained between the two codes; the effective doses were 12.02 mSv with PCXMC and 11.35 mSv with EGSnrc. The calculations can be completed on a PC without manual intervention in less than 15 minutes with PCXMC and in about 10 hours with EGSnrc, depending on the level of data grouping and accuracy desired.

Conclusion:

Effective dose and most organ doses in CBCT and interventional radiology calculated by PCXMC closely match those calculated by EGSnrc. Data grouping, which can be done automatically, makes the calculation time with PCXMC on a standard PC acceptable. This capability expands the dose information that can be provided by the DTS.

Partial support from NIH Grant R01‐EB002873 and Toshiba Medical Systems Corp.
TU‐D‐209‐06: Head and Neck Tissue Dose From X‐Ray Scatter to Physicians Performing Cardiovascular Procedures
Authors: Fetterly K , Schueler B , Grams M , Sturchio G
Published: July 2016

Purpose:

The purpose of this work was to characterize the spatial distribution of scatter radiation to the head and neck of a physician performing an x‐ray interventional procedure and assess brain, eye lens, and carotid artery dose.

Methods:

Radiographic x‐ray beams were tuned to match the peak energy (56 to 106 keV) and HVL (3.5 to 6.5 mm Al) of x‐ray scatter originating from a patient during a fluoroscopic procedure. The radiographic beam was directed upon a Rando phantom from an inferior‐left location to mimic a typical patient‐operator geometric relationship. A lead‐equivalent protective garment was secured to the phantom. Direct exposure Gafchromic film (XRQA2) was placed between the transverse plane layers of the head and neck region of the phantom and exposed with 4 scatter‐equivalent radiographic beams. A 3×3 cm2 film placed at the left collar of the phantom was used to monitor incident dose in the position of a radiation monitoring badge. The films were converted to 2D dose distribution maps using FilmQA Pro software and an Epson 11000‐XL scanner. The 2D dose distributions maps were normalized by the left collar dose and the percent of left collar dose (%LCD) was calculated for select tissues.

Results:

The dose maps had high dynamic range (104) and spatial detail. Considering all transverse planes and 4 scatter beam qualities, the median %LCD values were: whole brain 8.5%, left brain 13%, right brain 5.4%, left eye lens 67%, right eye lens 25%, left carotid artery 72%, and right carotid artery 28%.

Conclusion:

Scatter radiation dose to an operator can be simulated using a tuned radiographic beam and used to expose a phantom and Gafchromic film, thereby creating detailed 2D dose distribution maps. This work facilitates individualized estimation of dose to select head and neck tissues based on an operator's radiation monitoring badge value.
TU‐D‐209‐07: Monte Carlo Assessment of Dose to the Lens of the Eye of Radiologist Using Realistic Phantoms and Eyeglass Models
Authors: Xu X , Lin H , Gao Y , Caracappa P , Wang Y , Huo W , Pi Y , Feng M , Chen Z , Dauer L , Thornton R , Dauer Z , Alvarado K , St. Germain J , Solomon S
Published: July 2016

Purpose:

To study how eyeglass design features and postures of the interventional radiologist affect the radiation dose to the lens of the eye.

Methods:

A mesh‐based deformable phantom, consisting of an ultra‐fine eye model, was used to simulate postures of a radiologist in fluoroscopically guided interventional procedure (facing the patient, 45 degree to the left, and 45 degree to the right). Various eyewear design features were studied, including the shape, lead‐equivalent thickness, and separation from the face. The MCNPX Monte Carlo code was used to simulate the X‐ray source used for the transcatheter arterial chemoembolization procedure (The X‐ray tube is located 35 cm from the ground, emitting X‐rays toward to the ceiling; Field size is 40cm X 40cm; X‐ray tube voltage is 90 kVp). Experiments were also performed using dosimeter placed on a physical phantom behind eyeglasses.

Results:

Without protective eyewear, the radiologist's eye lens can receive an annual dose equivalent of about 80 mSv. When wearing a pair of lead eyeglasses with lead‐equivalent of 0.5‐mm Pb, the annual dose equivalent of the eye lens is reduced to 31.47 mSv, but both exceed the new ICRP limit of 20 mSv. A face shield with a lead‐equivalent of 0.125‐mm Pb in the shape of a semi‐cylinder (13cm in radius and 20‐cm in height) would further reduce the exposure to the lens of the eye. Examination of postures and eyeglass features reveal surprising information, including that the glass‐to‐eye separation also plays an important role in the dose to the eye lens from scattered X‐ray from underneath and the side. Results are in general agreement with measurements.

Conclusion:

There is an urgent need to further understand the relationship between the radiation environment and the radiologist's eyewear and posture in order to provide necessary protection to the interventional radiologists under newly reduced dose limits.
TU‐D‐207B‐01: A Prediction Model for Distinguishing Radiation Necrosis From Tumor Progression After Gamma Knife Radiosurgery Based On Radiomics Features From MR Images
Authors: Zhang Z , Ho A , Wang X , Brown P , Guha‐Thakurta N , Ferguson S , Fave X , Zhang L , Mackin D , Court L , Li J , Yang J
Published: July 2016

Purpose:

To develop and validate a prediction model using radiomics features extracted from MR images to distinguish radiation necrosis from tumor progression for brain metastases treated with Gamma knife radiosurgery.

Methods:

The images used to develop the model were T1 post‐contrast MR scans from 71 patients who had had pathologic confirmation of necrosis or progression; 1 lesion was identified per patient (17 necrosis and 54 progression). Radiomics features were extracted from 2 images at 2 time points per patient, both obtained prior to resection. Each lesion was manually contoured on each image, and 282 radiomics features were calculated for each lesion. The correlation for each radiomics feature between two time points was calculated within each group to identify a subset of features with distinct values between two groups. The delta of this subset of radiomics features, characterizing changes from the earlier time to the later one, was included as a covariate to build a prediction model using support vector machines with a cubic polynomial kernel function. The model was evaluated with a 10‐fold cross‐validation.

Results:

Forty radiomics features were selected based on consistent correlation values of approximately 0 for the necrosis group and >0.2 for the progression group. In performing the 10‐fold cross‐validation, we narrowed this number down to 11 delta radiomics features for the model. This 11‐delta‐feature model showed an overall prediction accuracy of 83.1%, with a true positive rate of 58.8% in predicting necrosis and 90.7% for predicting tumor progression. The area under the curve for the prediction model was 0.79.

Conclusion:

These delta radiomics features extracted from MR scans showed potential for distinguishing radiation necrosis from tumor progression. This tool may be a useful, noninvasive means of determining the status of an enlarging lesion after radiosurgery, aiding decision‐making regarding surgical resection versus conservative medical management.
TU‐D‐207B‐03: Early Assessment of Response to Chemoradiotherapy Based On Textural Analysis of Pre and Mid‐Treatment FDG‐PET Image in Locally Advanced Head and Neck Cancer
Authors: Cui Y , Pollom E , Loo B , Le Q , Hara W , Li R
Published: July 2016

Purpose:

To evaluate whether tumor textural features extracted from both pre‐ and mid‐treatment FDG‐PET images predict early response to chemoradiotherapy in locally advanced head and neck cancer, and investigate whether they provide complementary value to conventional volume‐based measurements.

Methods:

Ninety‐four patients with locally advanced head and neck cancers were retrospectively studied. All patients received definitive chemoradiotherapy and underwent FDG‐PET planning scans both before and during treatment. Within the primary tumor we extracted 6 textural features based on gray‐level co‐occurrence matrices (GLCM): entropy, dissimilarity, contrast, correlation, energy, and homogeneity. These image features were evaluated for their predictive power of treatment response to chemoradiotherapy in terms of local recurrence free survival (LRFS) and progression free survival (PFS). Logrank test were used to assess the statistical significance of the stratification between low‐ and high‐risk groups. P‐values were adjusted for multiple comparisons by the false discovery rate (FDR) method.

Results:

All six textural features extracted from pre‐treatment PET images significantly differentiated low‐ and high‐risk patient groups for LRFS (P=0.011–0.038) and PFS (P=0.029–0.034). On the other hand, none of the textural features on mid‐treatment PET images was statistically significant in stratifying LRFS (P=0.212–0.445) or PFS (P=0.168–0.299). An imaging signature that combines textural feature (GLCM homogeneity) and metabolic tumor volume showed an improved performance for predicting LRFS (hazard ratio: 22.8, P<0.0001) and PFS (hazard ratio: 13.9, P=0.0005) in leave‐one‐out cross validation. Intra‐tumor heterogeneity measured by textural features was significantly lower in mid‐treatment PET images than in pre‐treatment PET images (T‐test: P<1.4e‐6).

Conclusion:

Tumor textural features on pretreatment FDG‐PET images are predictive for response to chemoradiotherapy in locally advanced head and neck cancer. The complementary information offered by textural features improves patient stratification and may potentially aid in personalized risk‐adaptive therapy.
TU‐FG‐204‐02: An Overview of the CT Protocol Optimization Team at Johns Hopkins
Authors: Mahesh M.
Published: July 2016

The role of a medical physicist involved with clinical CT activities is changing rapidly. No longer is the physicist responsible for simply ensuring scanner QA. This shift is evident by looking at the trend to regulate more and more aspects of what activities must be performed to keep a CT practice within compliance. In this symposium, new guidelines from the ACR, Joint Commission, and several states will be addressed. An overview of these regulations will be provided. Then, three speakers will provide an in‐depth account of how their CT protocol Optimization team functions. Lastly, a representative from the Joint Commission will provide recent surveyor education, experience, and trend information.

Learning Objectives:

Understand the ACR, Joint Commission, and aspects of several state regulations/guidelines related to the clinical practice of CT.

Learn how a CT protocol optimization is organized and what tasks physicists perform from the perspective of four different institutions.

T. Szczykutowicz, TPS provides CT protocols to GE Healthcare under a license agreement. TPS receives grant support from GE Healthcare.
TU‐FG‐207B‐01: Report On Development of a Database of NIH Funding of Medical Physicists
Authors: Whelan B.
Published: July 2016

Up‐to‐date knowledge about federal funding opportunities related to medical physics research, as well as obtaining skills for writing effective grant proposals are critical for academic and entrepreneurial medical physicists. In this symposium, program directors from key federal research funding agencies, including the National Cancer Institute, the National Institute of Biomedical Imaging and Bioengineering, and the National Science Foundation, will present information about current funding opportunities relevant to the field of medical physics. They will also provide insight to issues that applicants should pay special attention to when crafting their research grant proposals. In addition, the symposium will include presentations on research funding for small business concerns, and the results of an independent AAPM study of the National Institutes of Health funding of AAPM members from 2002–2015.

Learning Objectives:

To learn about current federal funding initiatives relevant to medical physics research

To learn about tactics important for crafting convincing research proposals

To learn about an independent study of NIH funding of research done by AAPM members

B. Whelan, this work was commissioned and funded by the AAPM
TU‐F‐PinS Room/Hall E‐01: Hands‐on GE SenoClaire Digital Breast Tomosynthesis: Technical Characteristics & Quality Control
Authors: Lordache R.
Published: July 2016

This session along with the others on Digital Breast Tomosynthesis (DBT) offered at this years meeting as part of the Educational, Scientific and Partners in Solutions is intended to meet the FDA requirements for physicists to survey a DBT system. Specifically this vendor offered session held as part of the Partners in Solutions is also meant to focus on those requirements. This session is being done along with the other two vendors of approved DBT systems in order to cover the machine specific features of those systems.
TU‐G‐PinS Room/Hall E‐01: Hologic Tomosynthesis, Synthesized 2D, Tomo‐Guided Biopsy, and Dual Energy Imaging – System Design Principles and QC Protocols
Authors: Smith A.
Published: July 2016

This session along with the others on Digital Breast Tomosynthesis (DBT) offered at this years meeting as part of the Educational, Scientific and Partners in Solutions is intended to meet the FDA requirements for physicists to survey a DBT system. Specifically, this vendor offered session held as part of the Partners in Solutions is also meant to focus on those requirements. This session is being done along with the other two vendors of approved DBT systems in order to cover the machine specific features of those systems.
TU‐H‐201‐05: Panel Discussion Member
Authors: Fraass B.
Published: July 2016

The New New Symposium is a symposium for members relatively new to the organization to learn about the organizational structure and operational procedures of the society; how decisions are made, how the council and committee leadership is appointed and operates, opportunities for volunteer involvement, and a brief overview of the services and efforts provided by the HQ staff and the website. Attendees will hear from council chairs, key staff and chairs, and members with volunteer experience.

After the symposium a social hour ensues with opportunities to interact with key AAPM members. The New Member Symposium is a (free) ticket option when you register online for the Annual Meeting. And don't forget registrants receive one (free) ticket for a beverage of your choice during the social afterwards.
TU‐H‐BRC‐04: Feasibility of Using TomoDirect for Pulsed Reduced Dose‐Rate Radiotherapy
Authors: Geurts M
Published: July 2016

Purpose:

Pulsed reduced dose‐rate radiotherapy (PRDR) is a technique used for treatment of recurrent disease where a planned treatment is split into 0.2 Gy pulses, each separated by three‐minute intervals, to achieve a time averaged dose rate of 0.0667 Gy/min. This study investigated the feasibility of using TomoTherapy's fixed angle delivery feature (TomoDirect) to create high quality IMRT plans that meet the radiobiological constraints of PRDR.

Methods:

Two plans (one craniospinal irradiation and a complex shaped temporal lobe re‐irradiation) were created using a conventional technique and then TomoDirect. Plan quality was compared between techniques. Next, the dose rate to each voxel in the target was computed for each TomoDirect beam to verify that the time‐averaged dose rate is less than 0.0667 Gy/min.

Results:

The TomoDirect CSI plan provided improved target coverage and organ at risk sparing with a per‐beam treatment time ranging from 21.6 to 43.5 seconds and mean time‐averaged dose rate of 0.032 Gy/min. The TomoDirect temporal lobe plan showed equivalent plan quality to a non‐PRDR TomoHelical IMRT plan with per‐beam treatment times ranging from 43.7 to 44.9 seconds and a mean time‐averaged dose rate of 0.052 Gy/min.

Conclusion:

Our initial investigation suggests that TomoDirect PRDR is not only feasible but ideal for delivering superior conformality and target homogeneity to complex and large fields.
TU‐H‐BRC‐09: Validation of a Novel Therapeutic X‐Ray Array Source and Collimation System
Authors: Trovati S , Borchard P , King GJ , Limborg CG , Loo BW , Maxim P , McCormick D , Nicolas LY , Schueler E , Tantawi S , Wang J , Wang L
Published: July 2016

Purpose:

We have experimentally characterized and simulated the dosimetric properties and spatial fidelity of a novel X‐ray array source and collimation system called SPHINX that has the potential to generate complex intensity modulated X‐ray beams by varying the electron beam intensity only, and without any moving parts like in multi‐leaf collimators.

Methods:

We investigated the spatial fidelity and the X‐ray performances of a SPHINX prototype in tungsten, using a Cyber Knife and the experimental high‐energy electron beam line at XTA at SLAC National Laboratory. Dose distributions were recorded with gafchromic films, placed at the distal end of SPHINX and at several depths in a solid water phantom. The geometry of SPHINX and of the experimental set‐ups was also modeled in Monte Carlo (MC) simulations with the FLUKA code, used to reproduce the experimental results and, after validation, to predict and optimize the performance and design of the SPHINX.

Results:

The results indicate significant particle leakage through the channels during a single‐channel irradiation for high incident energies, followed by a rapid decrease for energies of clinical interest. When the collimator channels are used as target, the photon production increases, however at expense of the beam size that is also enlarged. The illumination of all channels simultaneously shows a fairly even transmission of the beam.

Conclusion:

With the measurements we have verified the MC models and the uniformity of beam transmission through SPHINX, and we have evaluated the importance of particle leakage through adjacent channels. These results can be used to optimize SPHINX design through the validated MC simulations.

Funding: Weston Havens Foundation, Office of the Dean of Medical School and Office of the Provost (Stanford University).

Loo, Maxim, Borchard, Tantawi are co‐founders of TibaRay Inc.

Loo and Tantawi are TibaRay Inc. board members.

Loo and Maxim received grants from Varian Medical Systems and RaySearch Laboratory.
TU‐H‐BRB‐00: Radiation Countermeasures Research and Development
Authors: Daniel J.
Published: July 2016

The US government has substantial research and development activities underway for medical countermeasures that will insure the long‐term safety and survival of the country's population after unfortunate large‐scale biological, chemical and radiological and nuclear events. Preparedness includes research and development of medical countermeasures to address radiation‐induced cutaneous and internal injury from radiation and nuclear events as well as for minimizing radiation risks incurred during and after travel in space. Other important research and development efforts include the repurposing of countermeasures and development of radioprotectors and mitigators to improve the outcome of radiation treatment. Participating agencies include NIAID, BARDA, NCI, and NASA, with examples of research and development funding that includes the Centers for Medical Countermeasures against Radiation (CMCR) consortia (NIAID) and primary and sub‐contracts with commercial entities (BARDA). Each of these programs requires substantial medical and health physics effort in collaboration with biology colleagues to provide a range of radiation sources, dosimetry instrumentation and assessment methods, and animal models for specific radiation‐induced effects and injuries. Radiation countermeasure activities for government agencies will be reviewed, the importance of model development will be stressed, example radiation countermeasure research projects will be reviewed, and the roles for medical physicists will be discussed.

Learning Objectives:

Review US national radiation countermeasure activities.

Review the roles for medical physicists in radiation countermeasures research and development.

Understand specific physics challenges in radiation research that need solutions.

Research for JD Bourland supported in part by: NIH/NIAID, U19 AI67798 (subcontract 131714). NIH/NCI, R01CA155293. HHSO10020130019C, BARDA/Argentum Medical LLC.; J. Bourland, Research supported in part by:

NIH/NIAID, U19 AI67798 (subcontract 131714); NIH/NCI, R01CA155293; HHSO10020130019C, BARDA/Argentum Medical LLC.; P. Prasanna, Supported by the Radiation Research Program, National Cancer Institute
TU‐H‐BRB‐01: Physics and Dosimetry for Radiation Countermeasure Research
Authors: Bourland J.
Published: July 2016

The US government has substantial research and development activities underway for medical countermeasures that will insure the long‐term safety and survival of the country's population after unfortunate large‐scale biological, chemical and radiological and nuclear events. Preparedness includes research and development of medical countermeasures to address radiation‐induced cutaneous and internal injury from radiation and nuclear events as well as for minimizing radiation risks incurred during and after travel in space. Other important research and development efforts include the repurposing of countermeasures and development of radioprotectors and mitigators to improve the outcome of radiation treatment. Participating agencies include NIAID, BARDA, NCI, and NASA, with examples of research and development funding that includes the Centers for Medical Countermeasures against Radiation (CMCR) consortia (NIAID) and primary and sub‐contracts with commercial entities (BARDA). Each of these programs requires substantial medical and health physics effort in collaboration with biology colleagues to provide a range of radiation sources, dosimetry instrumentation and assessment methods, and animal models for specific radiation‐induced effects and injuries. Radiation countermeasure activities for government agencies will be reviewed, the importance of model development will be stressed, example radiation countermeasure research projects will be reviewed, and the roles for medical physicists will be discussed.

Learning Objectives:

Review US national radiation countermeasure activities.

Review the roles for medical physicists in radiation countermeasures research and development.

Understand specific physics challenges in radiation research that need solutions.

Research for JD Bourland supported in part by: NIH/NIAID, U19 AI67798 (subcontract 131714). NIH/NCI, R01CA155293. HHSO10020130019C, BARDA/Argentum Medical LLC.; J. Bourland, Research supported in part by:

NIH/NIAID, U19 AI67798 (subcontract 131714); NIH/NCI, R01CA155293; HHSO10020130019C, BARDA/Argentum Medical LLC.; P. Prasanna, Supported by the Radiation Research Program, National Cancer Institute
TU‐H‐BRB‐02: The NIAID Radiation/Nuclear Medical Countermeasures Program
Authors: Taliaferro L.
Published: July 2016

The US government has substantial research and development activities underway for medical countermeasures that will insure the long‐term safety and survival of the country's population after unfortunate large‐scale biological, chemical and radiological and nuclear events. Preparedness includes research and development of medical countermeasures to address radiation‐induced cutaneous and internal injury from radiation and nuclear events as well as for minimizing radiation risks incurred during and after travel in space. Other important research and development efforts include the repurposing of countermeasures and development of radioprotectors and mitigators to improve the outcome of radiation treatment. Participating agencies include NIAID, BARDA, NCI, and NASA, with examples of research and development funding that includes the Centers for Medical Countermeasures against Radiation (CMCR) consortia (NIAID) and primary and sub‐contracts with commercial entities (BARDA). Each of these programs requires substantial medical and health physics effort in collaboration with biology colleagues to provide a range of radiation sources, dosimetry instrumentation and assessment methods, and animal models for specific radiation‐induced effects and injuries. Radiation countermeasure activities for government agencies will be reviewed, the importance of model development will be stressed, example radiation countermeasure research projects will be reviewed, and the roles for medical physicists will be discussed.

Learning Objectives:

Review US national radiation countermeasure activities.

Review the roles for medical physicists in radiation countermeasures research and development.

Understand specific physics challenges in radiation research that need solutions.

Research for JD Bourland supported in part by: NIH/NIAID, U19 AI67798 (subcontract 131714). NIH/NCI, R01CA155293. HHSO10020130019C, BARDA/Argentum Medical LLC.; J. Bourland, Research supported in part by:

NIH/NIAID, U19 AI67798 (subcontract 131714); NIH/NCI, R01CA155293; HHSO10020130019C, BARDA/Argentum Medical LLC.; P. Prasanna, Supported by the Radiation Research Program, National Cancer Institute
TU‐H‐BRA‐07: Design, Construction, and Installation of An Experimental Beam Line for the Development of MRI‐Linac Compatible Electron Accelerator
Authors: Whelan B , Keall P , Holloway L , Gierman S , Schmerge J , Tantawi S , Tremaine A , Trautwein A , Scott B , Fahrig R
Published: July 2016

Purpose:

MRI guided radiation therapy (MRIgRT) is a rapidly growing field; however, Linac operation in MRI fringe fields represents an ongoing challenge. We have previously shown in‐silico that Linacs could be redesigned to function in the in‐line orientation with no magnetic shielding by adopting an RF‐gun configuration. Other authors have also published insilico studies of Linac operation in magnetic fields; however to date no experimental validation data is published. This work details the design, construction, and installation of an experimental beam line to validate our in‐silico results.

Methods:

An RF‐gun comprising 1.5 accelerating cells and capable of generating electron energies up to 3.2MeV is used. The experimental apparatus was designed to monitor both beam current (toroid current monitor), spot size (two phosphor screens with viewports), and generate peak magnetic fields of at least 1000G (three variable current electromagnetic coils). Thermal FEM simulations were developed to ensure coil temperature remained within 100degC. Other design considerations included beam disposal, vacuum maintenance, radiation shielding, earthquake safety, and machine protection interlocks.

Results:

The beam line has been designed, built, and installed in a radiation shielded bunker. Water cooling, power supplies, thermo‐couples, cameras, and radiation shielding have been successfully connected and tested. Interlock testing, vacuum processing, and RF processing have been successfully completed. The first beam on is expected within weeks. The coil heating simulations show that with care, peak fields of up to 1200G (320G at cathode) can be produced using 40A current, which is well within the fields expected for MRI‐Linac systems. The maximum coil temperature at this current was 84degC after 6 minutes.

Conclusion:

An experimental beam line has been constructed and installed at SLAC in order to experimentally characterise RF gun performance in in‐line magnetic fields, validate in‐silico design work, and provide the first published experimental data relating to accelerator functionality for MRIgRT.