bluuebunny/crossref_metadata_2025 huggingface dataset:
SU‐G‐TeP4‐04: An Automated Monte Carlo Based QA Framework for Pencil Beam Scanning Treatments
Authors: Shin J , Jee K , Clasie B , Depauw N , Madden T , Sharp G , Paganetti H , Kooy H
Published: July 2016

Purpose:

Prior to treating new PBS field, multiple (three) patient‐field‐specific QA measurements are performed: two 2D dose distributions at shallow depth (M1) and at the tumor depth (M2) with treatment hardware at zero gantry angle; one 2D dose distribution at iso‐center (M3) without patient specific devices at the planned gantry angle. This patient‐specific QA could be simplified by the use of MC model. The results of MC model commissioning for a spot‐scanning system and the fully automated TOPAS/MC‐based QA framework will be presented.

Methods:

We have developed in‐house MC interface to access a TPS (Astroid) database from a computer cluster remotely. Once a plan is identified, the interface downloads information for the MC simulations, such as patient images, apertures points, and fluence maps and initiates calculations in both the patient and QA geometries. The resulting calculations are further analyzed to evaluate the TPS dose accuracy and the PBS delivery.

Results:

The Monte Carlo model of our system was validated within 2.0 % accuracy over the whole range of the dose distribution (proximal/shallow part, as well as target dose part) due to the location of the measurements. The averaged range difference after commissioning was 0.25 mm over entire treatment ranges, e.g., 6.5 cm to 31.6 cm.

Conclusion:

As M1 depths range typically from 1 cm to 4 cm from the phantom surface, The Monte Carlo model of our system was validated within +− 2.0 % in absolute dose level over a whole treatment range. The averaged range difference after commissioning was 0.25 mm over entire treatment ranges, e.g., 6.5 cm to 31.6 cm.

This work was supported by NIH/NCI under CA U19 21239
SU‐G‐TeP4‐10: Do Small Errors Matter When Treating Pituitary Adenoma Patients Using Gamma Knife?
Authors: Johnson P , Yang F , Lamichhane N
Published: July 2016

Purpose:

To determine whether positional errors on the order of 0.5–1 mm have any effect on critical structure dose or target coverage for pituitary adenoma patients treated with the Gamma Knife Perfexion.

Methods:

Treatment plans for six pituitary adenoma patients were modified to include positional shifts of 0.5 mm and 1 mm for each shot and in each cardinal direction. Twelve new plans were created per patient, and changes in target coverage and maximum dose to surrounding critical structures were recorded. Of particular interest were cases in which dose to the optic apparatus exceeded a tolerance of 8 Gy or dose to the brainstem exceeded a tolerance of 10–12 Gy. Target volumes ranged from 0.8–4.7 cc, and prescription doses ranged from 12–20 Gy.

Results:

Target coverage was significantly affected for only the smallest lesion. In this case, a shift of 1 mm in the superior or inferior direction resulted in a loss of coverage equal to 10%. A shift of 0.5 mm in the superior direction resulted in a loss of coverage equal to 4%. Critical structure tolerances were exceeded in 6/36 altered plans applying a 1 mm shift, and 3/36 altered plans applying a 0.5 mm shift. The increase in critical structure dose was between 2.0–2.7 Gy for these cases.

Conclusion:

In the world of radiosurgery accuracy is often quoted as sub‐millimeter. It is important to recognize, however, that even at this scale small errors can lead to situations where OAR tolerances are exceeded or target coverage is lost. The risk of such errors is dependent on the uncertainties involved with each step of the planning/treatment process. Future work will be devoted to better quantifying these uncertainties and defining the risk/benefit ratio for specific treatment approaches, i.e. margin vs no margin, optimization strategy, choice of prescription dose, etc.
SU‐G‐TeP4‐11: Implementation of a Non‐Measurement‐Based Patient‐Specific IMRT QA Program
Authors: Chen S , Guerrero M , Zhang B , Yi B , Mossahebi S , Prado K , D'Souza W , Langen K
Published: July 2016

Purpose:

To implement a comprehensive non‐measurement‐based verification program for patient‐specific IMRT QA

Methods:

Based on published guidelines, a robust IMRT QA program should assess the following components: 1) accuracy of dose calculation, 2) accuracy of data transfer from the treatment planning system (TPS) to the record‐and‐verify (RV) system, 3) treatment plan deliverability, and 4) accuracy of plan delivery.

Results:

We have implemented an IMRT QA program that consist of four components: 1) an independent re‐calculation of the dose distribution in the patient anatomy with a commercial secondary dose calculation program: Mobius3D (Mobius Medical Systems, Houston, TX), with dose accuracy evaluation using gamma analysis, PTV mean dose, PTV coverage to 95%, and organ‐at‐risk mean dose; 2) an automated in‐house‐developed plan comparison system that compares all relevant plan parameters such as MU, MLC position, beam iso‐center position, collimator, gantry, couch, field size settings, and bolus placement, etc. between the plan and the RV system; 3) use of the RV system to check the plan deliverability and further confirm using “mode‐up” function on treatment console for plans receiving warning; and 4) implementation of a comprehensive weekly MLC QA, in addition to routine accelerator monthly and daily QA. Among 1200 verifications, there were 9 cases of suspicious calculations, 5 cases of delivery failure, no data transfer errors, and no failure of weekly MLC QA. These 9 suspicious cases were due to the PTV extending to the skin or to heterogeneity correction effects, which would not have been caught using phantom measurement‐based QA. The delivery failure was due to the rounding variation of MLC position between the planning system and RV system.

Conclusion:

A very efficient, yet comprehensive, non‐measurement‐based patient‐specific QA program has been implemented and used clinically for about 18 months with excellent results
SU‐G‐TeP4‐12: Individual Beam QA for a Robotic Radiosurgery System Using a Scintillator Cone
Authors: McGuinness C , Descovich M , Sudhyadhom A
Published: July 2016

Purpose:

The targeting accuracy of the Cyberknife system is measured by end‐to‐end tests delivering multiple isocentric beams to a point in space. While the targeting accuracy of two representative beams can be determined by a Winston‐Lutz‐type test, no test is available today to determine the targeting accuracy of each clinical beam. We used a scintillator cone to measure the accuracy of each individual beam.

Methods:

The XRV‐124 from Logos Systems Int'l is a scintillator cone with an imaging system that is able to measure individual beam vectors and a resulting error between planned and measured beam coordinates. We measured the targeting accuracy of isocentric and non‐isocentric beams for a number of test cases using the Iris and the fixed collimator.

Results:

Collimator‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐Num. Beams‐‐‐‐‐‐‐Avg. Diff. (mm)‐‐‐‐‐‐StDev. (mm)‐‐‐‐‐‐‐‐Max Diff. (mm)Fixed 10mm____________52___________0.837____________0.380___________1.73Iris 10mm______________52___________1.076____________0.433___________1.873Iris 12.5mm____________52___________1.232____________0.489___________2.043Iris 15mm______________52___________1.218____________0.475___________2.01Iris 20mm______________52___________1.202____________0.501___________2.508Iris 25mm______________52___________1.234____________0.494___________2.32Iris 30mm______________52___________1.096____________0.483___________2.433PlanQA Fixed 20mm______86___________0.900____________0.388___________1.667 PlanQA Iris 12.5–30mm___164__________0.806____________0.313___________1.571 The average difference between plan and measured beam position was 0.8–1.2mm across the collimator sizes and plans considered here. The max error for a single beam was 2.5mm for the isocentric plans, and 1.67mm for the non‐isocentric plans. The standard deviation of the differences was 0.5mm or less.

Conclusion:

The CyberKnife System is specified to have an overall targeting accuracy for static targets of less than 0.95mm. In E2E tests using the XRV124 system we measure average beam accuracy between 0.8 to 1.23mm, with maximum of 2.5mm. We plan to investigate correlations between beam position error and robot position, and to quantify the effect of beam position errors on patient specific plans.

Martina Descovich has received research support and speaker honoraria from Accuray
MO‐AB‐204‐02: IHE RAD
Authors: Seibert J.
Published: July 2016

You've experienced the frustration: vendor A's device claims to work with vendor B's device, but the practice doesn't match the promise. Getting devices working together is the hidden art that Radiology and Radiation Oncology staff have to master. To assist with that difficult process, the Integrating the Healthcare Enterprise (IHE) effort was established in 1998, with the coordination of the Radiological Society of North America.

Integrating the Healthcare Enterprise (IHE) is a consortium of healthcare professionals and industry partners focused on improving the way computer systems interconnect and exchange information. This is done by coordinating the use of published standards like DICOM and HL7. Several clinical and operational IHE domains exist in the healthcare arena, including Radiology and Radiation Oncology. The ASTRO‐sponsored IHE Radiation Oncology (IHE‐RO) domain focuses on radiation oncology specific information exchange. This session will explore the IHE Radiology and IHE RO process for;

IHE solicitation process for new profiles.

Improving the way computer systems interconnect and exchange information in the healthcare enterprise

Supporting interconnectivity descriptions and proof of adherence by vendors

Testing and assuring the vendor solutions to connectivity problems.

Including IHE profiles in RFPs for future software and hardware purchases.

Learning Objectives:

Understand IHE role in improving interoperability in health care.

Understand process of profile development and implantation.

Understand how vendors prove adherence to IHE RO profiles.

S. Hadley, ASTRO Supported Activity
MO‐AB‐204‐04: Connectathons and Testing
Authors: Bosch W.
Published: July 2016

You've experienced the frustration: vendor A's device claims to work with vendor B's device, but the practice doesn't match the promise. Getting devices working together is the hidden art that Radiology and Radiation Oncology staff have to master. To assist with that difficult process, the Integrating the Healthcare Enterprise (IHE) effort was established in 1998, with the coordination of the Radiological Society of North America.

Integrating the Healthcare Enterprise (IHE) is a consortium of healthcare professionals and industry partners focused on improving the way computer systems interconnect and exchange information. This is done by coordinating the use of published standards like DICOM and HL7. Several clinical and operational IHE domains exist in the healthcare arena, including Radiology and Radiation Oncology. The ASTRO‐sponsored IHE Radiation Oncology (IHE‐RO) domain focuses on radiation oncology specific information exchange. This session will explore the IHE Radiology and IHE RO process for;

IHE solicitation process for new profiles.

Improving the way computer systems interconnect and exchange information in the healthcare enterprise

Supporting interconnectivity descriptions and proof of adherence by vendors

Testing and assuring the vendor solutions to connectivity problems.

Including IHE profiles in RFPs for future software and hardware purchases.

Learning Objectives:

Understand IHE role in improving interoperability in health care.

Understand process of profile development and implantation.

Understand how vendors prove adherence to IHE RO profiles.

S. Hadley, ASTRO Supported Activity
MO‐A‐BRB‐01: TG191: Clinical Use of Luminescent Dosimeters
Authors: Kry S.
Published: July 2016

This presentation will highlight the upcoming TG‐191 report: Clinical Use of Luminescent Dosimeters. Luminescent dosimetry based on TLD and OSLD is a practical, accurate, and precise technique for point dosimetry in medical physics applications. The charges of Task Group 191 were to detail the methodologies for practical and optimal luminescent dosimetry in a clinical setting. This includes (1) To review the variety of TLD/OSL materials available, including features and limitations of each. (2) To outline the optimal steps to achieve accurate and precise dosimetry with luminescent detectors and to evaluate the uncertainty induced when less rigorous procedures are used. (3) To develop consensus guidelines on the optimal use of luminescent dosimeters for clinical practice. (4) To develop guidelines for special medically relevant uses of TLDs/OSLs (e.g., mixed field i.e. photon/neutron dosimetry, particle beam dosimetry, skin dosimetry). While this report provides general guidelines for arbitrary TLD and OSLD processes, the report, and therefore this presentation, provide specific guidance for TLD‐100 (LiF:Ti,Mg) and nanoDot (Al2O3:C) dosimeters because of their prevalence in clinical practice.

Learning Objectives:

Understand the available dosimetry systems, and basic theory of their operation

Understand the range of dose determination methodologies and the uncertainties associated with them

Become familiar with special considerations for TLD/OSLD relevant for special clinical situations

Learn recommended commissioning and QA procedures for these dosimetry systems.
MO‐AB‐BRA‐04: Radiation Measurements with a DNA Double‐Strand‐Break Dosimeter
Authors: Obeidat M , Cline K , Stathakis S , Papanikolaou N , Rasmussen K , Gutierrez A , Ha CS , Lee SE , Shim EY , Kirby N
Published: July 2016

Purpose:

Many types of dosimeters are used to measure radiation, but none of them directly measures the biological effect of this dose. The purpose here is to create a dosimeter that can measure the probability of double‐strand breaks (DSB) for DNA, which is directly related to the biological effect of radiation.

Methods:

The dosimeter has DNA strands, which are labeled on one end with biotin and on the other with fluorescein. The biotin attaches these strands to magnetic beads. We suspended the DNA dosimeter in phosphate‐buffered saline (PBS) as it matches the internal environment of the body. We placed small volumes (50µL) of the DNA dosimeter into tubes and irradiated these samples in a water‐equivalent plastic phantom with several doses (three samples per dose). After irradiating the samples, a magnet was placed against the tubes. The fluorescein attached to broken DNA strands was extracted (called the supernatant) and placed into a different tube. The fluorescein on the unbroken strands remained attached to the beads in the tube and was re‐suspended with 50µL of PBS. A fluorescence reader was used to measure the fluorescence for both the re‐suspended beads and supernatant. To prove that we are measuring DSB, we tested dosimeter response with two different lengths of attached DNA strands (1 and 4 kilo‐base pair).

Results:

The probability of DSB at the dose levels of 5, 10, 25, and 50 Gy were 0.05, 0.08, 0.12, and 0.19, respectively, while the coefficients of variation were 0.14, 0.07, 0.02, and 0.01, respectively. The 4 kilo‐base‐pair dosimeter produced 5.3 times the response of the 1 kilo‐base‐pair dosimeter.

Conclusion:

The DNA dosimeter yields a measurable response to dose that scales with the DNA strand length. The goal now is to refine the dosimeter fabrication to reproducibly create a low coefficient of variation for the lower doses.

This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)
MO‐AB‐BRA‐10: Super High Temporal Resolution Cardiac CT Imaging Using SMART‐RECON
Authors: Li Y , Cao X , Xing Z , Sun X , Hsieh J , Chen G
Published: July 2016

Purpose:

Coronary CT angiography is a challenging task currently limited by the achievable temporal resolution of modern MDCT scanners. In this work, a highly innovative method has been developed and validated to improve temporal resolution of the MDCT by a factor of four with the newly developed SMART‐RECON method to enable high quality coronary CTA exams. The primary purpose of this paper is to investigate the relationships between: (1) SMART‐RECON and the motion pattern; (2) SMART‐RECON and the average speed of moving vessels; (3) SMART‐RECON and the position and direction of moving vessels.

Methods:

Using data acquired from a short scan angular range, the entire cardiac window is divided into 4–5 narrower cardiac windows, each corresponding to a 60‐degree angular sector. These 4–5 sub‐cardiac phase images can be jointly reconstructed with SMART‐RECON to globally improve temporal resolution and noise properties. A hybrid phantom consisting of realistic cardiac anatomy and eight moving objects was constructed to validate the method under a wide variety of conditions and studied quantitatively. Additionally, in vivo data from twenty human subjects were used to demonstrate that SMART‐RECON can significantly improve the quality of CTA using a Discovery CT 750 HD (GE Healthcare, WI, USA) with 350 ms gantry rotation time.

Results:

The performance of the proposed SMART‐RECON cardiac CT imaging method is independent of motion speed, orientation, and location as long as there is a motionless phase that corresponds to 60° angular range. In contrast, the currently available FBP cardiac reconstruction with Parker weights demonstrates significant motion artifacts. The human subject results also demonstrate the significant improvement of coronary CTA quality cross all subjects.

Conclusion:

With a single short‐scan acquisition, SMART‐RECON can be used to systematically improve the temporal resolution for MDCT cardiac CT imaging by a factor of 4 with no prior knowledge of motion.

Funding support: This work was support in part by GE Healthcare. Disclosures: Y. Li: None. X. Cao, Z. Xing, X. Sun and H. Jiang: GE employee. G. Chen: Research contract with GE Healthcare; Research contract with Siemens AX; Royalty received from GE Healthcare
MO‐AB‐206‐02: Testing Gamma Cameras Based On TG177 WG Report
Authors: Halama J.
Published: July 2016

This education session will cover the physics and operation principles of gamma cameras and PET scanners.

The first talk will focus on PET imaging. An overview of the principles of PET imaging will be provided, including positron decay physics, and the transition from 2D to 3D imaging. More recent advances in hardware and software will be discussed, such as time‐of‐flight imaging, and improvements in reconstruction algorithms that provide for options such as depth‐of‐interaction corrections. Quantitative applications of PET will be discussed, as well as the requirements for doing accurate quantitation. Relevant performance tests will also be described.

Learning Objectives:

Be able to describe basic physics principles of PET and operation of PET scanners.

Learn about recent advances in PET scanner hardware technology.

Be able to describe advances in reconstruction techniques and improvements

Be able to list relevant performance tests.

The second talk will focus on gamma cameras. The Nuclear Medicine subcommittee has charged a task group (TG177) to develop a report on the current state of physics testing of gamma cameras, SPECT, and SPECT/CT systems. The report makes recommendations for performance tests to be done for routine quality assurance, annual physics testing, and acceptance tests, and identifies those needed satisfy the ACR accreditation program and The Joint Commission imaging standards. The report is also intended to be used as a manual with detailed instructions on how to perform tests under widely varying conditions.

Learning Objectives:

At the end of the presentation members of the audience will:

Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of gamma cameras for planar imaging.

Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of SPECT systems.

Be familiar with the tests of a SPECT/CT system that include the CT images for SPECT reconstructions.

Become knowledgeable of items to be included in annual acceptance testing reports including CT dosimetry and PACS monitor measurements.

T. Turkington, GE Healthcare
MO‐A‐209‐01: AAPM Journal Finances: Facts, Figures, and Fundamentals
Authors: Armato S.
Published: July 2016

Scientific publishing is a major endeavor of the AAPM. Although publishing requires substantial resources, it has the potential to generate both reputation and revenue to further the missions of our society. The AAPM owns and publishes two journals: Medical Physics and the Journal of Applied Clinical Medical Physics (JACMP). Medical Physics, with the tagline “The international journal of medical physics research and practice,” publishes research concerned with the application of physics and mathematics to the solution of problems in medicine and human biology, with an emphasis on theoretical and experimental approaches. The JACMP is an applied journal that publishes papers designed to help clinical medical physicists perform their responsibilities more effectively and efficiently for the greater benefit of patients. The two journals reflect two different missions, reach two different (yet often overlapping) audiences, engage two different publication approaches, and operate under two different financial models. A journal must serve both “producers” (authors who submit manuscripts to – and ultimately have their work published in – the journal) and “consumers” (readers – either individuals who access journal content or subscribing institutions that make the journal's content available to its members). Any viable publication model and cost‐recovery structure must satisfy the interests of both groups without sacrificing the needs of the scientific community. The purpose of this symposium is to explore the roles of the AAPM's two journals in advancing the scientific and clinical missions of the society and to understand the complex interplay of economic factors that impact financial decisions governing the journals and the returns they bring to the AAPM.

Learning Objectives:

Appreciate the complementary roles of Medical Physics and JACMP in advancing the scientific and clinical missions of the AAPM.

Understand AAPM resources committed to the two journals and the return on these investments.

Understand the role of the AAPM's Journals Business Management Committee in the financial stability of the two journals.

Explore the potential benefits and pitfalls of various economic and publication models for the two journals.

J. Bourland, Member, Journals Business Management Committee, AAPM.
MO‐B‐201‐00: Motion Management in Current Stereotactic Body Radiation Therapy (SBRT) Practice
Authors: Shang Charles
Published: July 2016

The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on‐going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects to these different imaging processes is a prerequisite for a decent motion management program. The commonly used motion control techniques to physically restrict tumor motion, if adopted correctly, effectively increase the conformity and accuracy of hypofractionated treatment. The effective application of such requires one to understand the mechanics of the application and the related physiology especially related to respiration. The image‐guided radiation beam control, or tumor tracking, further realized the endeavor for precision‐targeting. During tumor tracking, the respiratory motion is often constantly monitored by non‐ionizing beam sources using the body surface as its surrogate. This then has to synchronize with the actual internal tumor motion. The latter is often accomplished by stereo X‐ray imaging or similar techniques. With these advanced technologies, one may drastically reduce the treated volume and increase the clinicians’ confidence for a high fractional ablative radiation dose. However, the challenges in implementing the motion management may not be trivial and is dependent on each clinic case. This session of presentations is intended to provide an overview of the current techniques used in managing the tumor motion in SBRT, specifically for routine lung SBRT, proton based treatments, and newly‐developed MR guided RT.

Learning Objectives:

Through this presentation, the audience will

understand basic roles of commonly used imaging modalities for lung cancer studies;

familiarize the major advantages and limitations of each discussed motion control methods;

familiarize the major advantages and limitations of each discussed radiation beam control methodology and tumor tacking method;

understand the key points in motion management for a high quality SBRT program.
MO‐B‐201‐03: MRI‐Guided Tracking and Gating
Authors: Green O.
Published: July 2016

The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on‐going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects to these different imaging processes is a prerequisite for a decent motion management program. The commonly used motion control techniques to physically restrict tumor motion, if adopted correctly, effectively increase the conformity and accuracy of hypofractionated treatment. The effective application of such requires one to understand the mechanics of the application and the related physiology especially related to respiration. The image‐guided radiation beam control, or tumor tracking, further realized the endeavor for precision‐targeting. During tumor tracking, the respiratory motion is often constantly monitored by non‐ionizing beam sources using the body surface as its surrogate. This then has to synchronize with the actual internal tumor motion. The latter is often accomplished by stereo X‐ray imaging or similar techniques. With these advanced technologies, one may drastically reduce the treated volume and increase the clinicians’ confidence for a high fractional ablative radiation dose. However, the challenges in implementing the motion management may not be trivial and is dependent on each clinic case. This session of presentations is intended to provide an overview of the current techniques used in managing the tumor motion in SBRT, specifically for routine lung SBRT, proton based treatments, and newly‐developed MR guided RT.

Learning Objectives:

Through this presentation, the audience will

understand basic roles of commonly used imaging modalities for lung cancer studies;

familiarize the major advantages and limitations of each discussed motion control methods;

familiarize the major advantages and limitations of each discussed radiation beam control methodology and tumor tacking method;

understand the key points in motion management for a high quality SBRT program.
MO‐B‐BRB‐02: 3D Dosimetry in the Clinic: IMRT Technique Validation in Sweden
Authors: Ceberg S.
Published: July 2016

Full three‐dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging.

In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques.

Learning Objectives:

L. John Schreiner: Background and Motivation

Understand recent developments enabling clinically practical 3D dosimetry,

Appreciate 3D dosimetry workflow and dosimetry procedures, and

Observe select examples from the clinic.

Sofie Ceberg: Application to dynamic radiotherapy

Observe full dosimetry under dynamic radiotherapy during respiratory motion, and

Understand how the measurement of high resolution dose data in an irradiated volume can help understand interplay effects during TomoTherapy or VMAT.

Titania Juang: Special techniques in the clinic and research

Understand the potential for 3D dosimetry in validating dose accumulation in deformable systems, and

Observe the benefits of high resolution measurements for precision therapy in SRS and in MicroSBRT for small animal irradiators

Geoffrey S. Ibbott: 3D Dosimetry in end‐to‐end dosimetry QA

Understand the potential for 3D dosimetry for end‐to‐end radiation therapy process validation in the in‐house and external credentialing setting.

Canadian Institutes of Health Research; L. Schreiner, Modus QA, London, ON, Canada; T. Juang, NIH R01CA100835
MO‐B‐BRB‐03: 3D Dosimetry in the Clinic: Validating Special Techniques
Authors: Juang T.
Published: July 2016

Full three‐dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging.

In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques.

Learning Objectives:

L. John Schreiner: Background and Motivation

Understand recent developments enabling clinically practical 3D dosimetry,

Appreciate 3D dosimetry workflow and dosimetry procedures, and

Observe select examples from the clinic.

Sofie Ceberg: Application to dynamic radiotherapy

Observe full dosimetry under dynamic radiotherapy during respiratory motion, and

Understand how the measurement of high resolution dose data in an irradiated volume can help understand interplay effects during TomoTherapy or VMAT.

Titania Juang: Special techniques in the clinic and research

Understand the potential for 3D dosimetry in validating dose accumulation in deformable systems, and

Observe the benefits of high resolution measurements for precision therapy in SRS and in MicroSBRT for small animal irradiators

Geoffrey S. Ibbott: 3D Dosimetry in end‐to‐end dosimetry QA

Understand the potential for 3D dosimetry for end‐to‐end radiation therapy process validation in the in‐house and external credentialing setting.

Canadian Institutes of Health Research; L. Schreiner, Modus QA, London, ON, Canada; T. Juang, NIH R01CA100835
MO‐B‐209‐01: Certificate Extension Process for DBT and the Medical Physicist's Role
Authors: Chakrabarti K.
Published: July 2016

This presentation will describe the role of medical physicists during FDA's certificate extension process (CE). The presentation will outline FDA's CE process, with detailed discussions on training, MEE, and requirements for continued QA for the facility, vis‐a‐vis medical physicist's responsibilities. A few important tests will be discussed that need special emphasis for each of the DBT systems currently approved by FDA. What can be accepted as additional didactic and hands on training in fulfilling modality related training will be explained.

Learning Objectives:

Understand the certificate extension process

Understand medical physicist's responsibility in performing QC tests following the QC manual

Learn about proper presentation of data in reporting and generating soft copy phantom image

Understand on‐going responsibilities in monitoring QC technologists’ tests
MO‐DE‐204‐04: Dose Optimization in CT: Trends and Motivation in the US
Authors: Kofler J.
Published: July 2016

The main topic of the session is to show how dose optimization is being implemented in various regions of the world, including Europe, Australia, North America and other regions.

A multi‐national study conducted under International Atomic Energy Agency (IAEA) across more than 50 less resourced countries gave insight into patient radiation doses and safety practices in CT, mammography, radiography and interventional procedures, both for children and adults. An important outcome was the capability development on dose assessment and management.

An overview of recent European projects related to CT radiation dose and optimization both to adults and children will be presented. Existing data on DRLs together with a European methodology proposed on establishing and using DRLs for paediatric radiodiagnostic imaging and interventional radiology practices will be shown.

Compared with much of Europe at least, many Australian imaging practices are relatively new to the task of diagnostic imaging dose optimisation. In 2008 the Australian Government prescribed a requirement to periodically compare patient radiation doses with diagnostic reference levels (DRLs), where DRLs have been established. Until recently, Australia had only established DRLs for computed tomography (CT). Regardless, both professional society and individual efforts to improved data collection and develop optimisation strategies across a range of modalities continues. Progress in this field, principally with respect to CT and interventional fluoroscopy will be presented.

In the US, dose reduction and optimization efforts for computed tomography have been promoted and mandated by several organizations and accrediting entities. This presentation will cover the general motivation, implementation, and implications of such efforts.

Learning Objectives:

Understand importance of the dose optimization in Diagnostic Radiology.

See how this goal is achieved in different regions of the World.

Learn about the global trend in the dose optimization and future prospectives.

M. Rehani, The work was a part of the work of IAEA where I was an employee and IAEA is a United Nations organization
MO‐C‐BRB‐00: President's Symposium: Inspiring Leadership
Authors: Curran Bruce
Published: July 2016

With the profound changes currently occurring in medicine, the role of the medical physicist cannot stagnate, but must evolve to meet the challenges and opportunities that are presented. Medical physicists must understand these changes and establish themselves not only as relevant but as leaders in this new environment. We must increase our presence in clinical settings such as tumor boards, patient rounds, and the development of new diagnosis, imaging, and treatment techniques. By establishing ourselves as competent scientists, we can and must participate in the development of technologies through research, teaching, and clinical implementation. As medical physicists we must define our roles and value to our physician colleagues, patients, referring physicians, and senior administrators. We cannot afford to be viewed solely as quality assurance technologists, but need to move forward in step with medical and practice advances, becoming recognized as having a leadership role in providing quality research, technological development, and quality patient care.

In this session, four leaders in medical research and healthcare will discuss their observations on how medical physicists have contributed to advancements in healthcare and opportunities to continue leadership in providing quality medicine through the applications of physics to research, education, and clinical practice.

Learning Objectives:

Understand the changes in the healthcare environment and how medical physicists can contribute to improving patient care.

Learn how medical physicists are currently leading research efforts to improve clinical imaging and diagnosis.

Understand the role of medical physicists in developing new technology and leading its translation into clinical care.
MO‐D‐BRB‐00: SBRT Workflow Overview
Authors: Xing Lei
Published: July 2016

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image‐guided patient setup and on‐treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real‐time image guidance during SBRT dose delivery using gated/un‐gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state‐of‐art imaging and planning techniques.

Learning Objectives:

Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA.

Update on the use of multi‐dimensional and multi‐modality imaging for reliable guidance of SBRT.

Discuss treatment planning and QA issues specific to SBRT.

Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT.

NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems
MO‐DE‐BRA‐01: Flipped Physics Courses Within a Radiologic Technologist Program: Video Production and Long Term Outcomes
Authors: Oshiro T , Donaghy M , Slechta A
Published: July 2016

Purpose:

To determine if the flipped class format has an effect on examination results for a radiologic technologist (RT) program and discuss benefits from creating video resources.

Methods:

From 2001–2015, students had taken both a radiological physics and quality control (QC) class as a part of their didactic training. In 2005/2006, the creation of videos of didactic lectures and QC test demonstrations allowed for a flip where content was studied at home while exercises and reviews were done in‐class. Final examinations were retrospectively reviewed from this timeframe. 12 multiple choice physics questions (MCP) and 5 short answer QC questions (SAQC) were common to pre and post flip exams. The RT program's ARRT exam scores were also obtained and compared to national averages.

Results:

In total, 36 lecture videos and 65 quality control videos were created for the flipped content. Data was ∼2.4GB and distributed to students via USB or CD media. For MCP questions, scores improved by 7.9% with the flipped format and significance (Student's t‐test, p<0.05) was found for 3 of the 12 questions. SAQC questions showed improvement by 14.6% and significance was found for 2 of the 5 questions. Student enrollment increased from ∼14 (2001–2004) to ∼23 students (2005–15). Content was continuously added post‐flip due to the efficiency of delivery. The QC class in 2003 covered 45 test setups in‐class while 65 were covered with video segments in 2014. Flipped materials are currently being repurposed. In 2015, this video content was restructured into an ARRT exam review guide and in 2016, the content was reorganized for fluoroscopy training for physicians.

Conclusion:

We believe that flipped classes can improve efficiency of content delivery and improve student performance even with an increase in class size. This format allows for flexibility in learning as well as re‐use in multiple applications.
TU‐A‐BRB‐03: Panel Member
Authors: Winey B.
Published: July 2016

Brain stereotactic radiosurgery (SRS) and spine stereotactic body radiation therapy (SBRT) are commonly treated by a multidisciplinary team of neurosurgeons, radiation oncologists, and medical physicists. However the treatment objectives, constraints, and technical considerations involved can be quite different between the two techniques. In this interactive session an expert panel of speakers will present clinical brain SRS and spine SBRT cases in order to demonstrate real‐world considerations for ensuring safe and accurate treatment delivery and to highlight the significant differences in approach for each treatment site. The session will include discussion of topic such as clinical indications, immobilization, target definition, normal tissue tolerance limits, and beam arrangements.

Learning Objectives:

Understand the differences in indications and dose/fractionation strategies for intracranial SRS and spine SBRT.

Describe the different treatment modalities which can be used to deliver intracranial SRS and spine SBRT.

Cite the major differences in treatment setup and delivery principles between intracranial and spine treatments.

Identify key critical structures and clinical dosimetric tolerance levels for spine SBRT and intracranial SRS.

Understand areas of ongoing work to standardize intracranial SRS and spine SBRT procedures.

Schlesinger: Research support: Elekta Instruments, AB; D. Schlesinger, Elekta Instruments, AB ‐ research support; B. Winey, No relevant external funding for this subject.
TU‐AB‐BRA‐04: An Investigation of Metal Artifact Effects in Multi‐Modalities: Development of MRI‐CT Heterogeneous Head and Neck Phantom for MRI‐CT Registration
Authors: Lee M , Song K , Choe B , Suh T
Published: July 2016

Purpose:

The purpose of this investigation was to develop an CT‐MR head and neck phantom which can investigate dose calculation differences between density‐assigned MRI and CT, and to compare non‐implant inserted registered MR‐CT registered image with artifact reduced image of MR‐CT registered image. It is to identify potential limitations related to dental implants of MR image and CT image and maximize the advantages to find interactive method to use registered image.

Methods:

The phantom comprises half‐circled shape which shaped to simulated the anatomical structures of a human head and neck. Through applying various clinical cases, the developed phantom is closely allied to human. Developed phantom can be verified in to opened‐mouth and closed‐mouth phantom. The case of the phantom was made of acrylic, which introduces a 0.003 parts per million (ppm) phase shift, whereas the Teflon results in a 0.03 ppm shift measured at 3T which represents human bone. Both materials are considered acceptable for MR field measurements. The phantom was filled with a solution of nickel chloride and sodium chloride. The implants and teeth were imaged by means of 3T MRI system.

Results:

In MRI image, the metal artifact reduced and the results in improved image quality and reduction of susceptibility artifacts originate in MR images. CT and MR artifact correction method resulted in substantial artifact reduction, both quantitatively and qualitatively. On head and neck CT images, it remained anatomical conformation but it has reduced streak and dark artifact which appeared around the dental restoration. The artifact reduced MR‐CT image improved image quality and calculation accuracy for patients with severe CT artifacts.

Conclusion:

By using MRI/CT and the artifact‐free slice location of the phantom, we demonstrated that the proposed artifact reduction method can effectively remove streak artifacts from a metal object.
TU‐AB‐BRA‐06: BEST IN PHYSICS (JOINT IMAGING‐THERAPY): An MRI Compatible Externally and Internally Deformable Lung Motion Phantom for Multi‐Modality IGRT
Authors: Sabouri P , Arai T , Sawant A
Published: July 2016

Purpose:

MRI has become an attractive tool for tumor motion management. Current MR‐compatible phantoms are only capable of reproducing translational motion. This study describes the construction and validation of a more realistic, MRI‐compatible lung phantom that is deformable internally as well as externally. We demonstrate a radiotherapy application of this phantom by validating the geometric accuracy of the open‐source deformable image registration software NiftyReg (UCL, UK).

Methods:

The outer shell of a commercially‐available dynamic breathing torso phantom was filled with natural latex foam with eleven water tubes. A rigid foam cut‐out served as the diaphragm. A high‐precision programmable, in‐house, MRI‐compatible motion platform was used to drive the diaphragm. The phantom was imaged on a 3T scanner (Philips, Ingenia). Twenty seven tumor traces previously recorded from lung cancer patients were programmed into the phantom and 2D+t image sequences were acquired using a sparse‐sampling sequence k‐t BLAST (accn=3, resolution=0.66×0.66×5mm3; acquisition‐time=110ms/slice). The geometric fidelity of the MRI‐derived trajectories was validated against those obtained via fluoroscopy using the on board kV imager on a Truebeam linac. NiftyReg was used to perform frame by frame deformable image registration. The location of each marker predicted by using NiftyReg was compared with the values calculated by intensity‐based segmentation on each frame.

Results:

In all cases, MR trajectories were within 1 mm of corresponding fluoroscopy trajectories. RMSE between centroid positions obtained from segmentation with those obtained by NiftyReg varies from 0.1 to 0.21 mm in the SI direction and 0.08 to 0.13 mm in the LR direction showing the high accuracy of deformable registration.

Conclusion:

We have successfully designed and demonstrated a phantom that can accurately reproduce deformable motion under a variety of imaging modalities including MRI, CT and x‐ray fluodoscopy, making it an invaluable research tool for validating novel motion management strategies.

This work was partially supported through research funding from National Institutes of Health (R01CA169102).