bluuebunny/crossref_metadata_2025 huggingface dataset:
WE‐EF‐BRA‐02: A Monte Carlo Study of Macroscopic and Microscopic Dose Descriptors for Kilovoltage Cellular Dosimetry
Authors: Oliver P , Thomson R
Published: June 2015

Purpose:

To investigate how doses to cellular (microscopic) targets depend on cell morphology, and how cellular doses relate to doses to bulk tissues and water for 20 to 370 keV photon sources using Monte Carlo (MC) simulations.

Methods:

Simulation geometries involve cell clusters, single cells, and single nuclear cavities embedded in various healthy and cancerous bulk tissue phantoms. A variety of nucleus and cytoplasm elemental compositions are investigated. Cell and nucleus radii range from 5 to 10 microns and 2 to 9 microns, respectively. Doses to water and bulk tissue cavities are compared to nucleus and cytoplasm doses.

Results:

Variations in cell dose with simulation geometry are most pronounced for lower energy sources. Nuclear doses are sensitive to the surrounding geometry: the nuclear dose in a multicell model differs from the dose to a cavity of nuclear medium in an otherwise homogeneous bulk tissue phantom by more than 7% at 20 keV. Nuclear doses vary with cell size by up to 20% at 20 keV, with 10% differences persisting up to 90 keV. Bulk tissue and water cavity doses differ from cellular doses by up to 16%. MC results are compared to cavity theory predictions; large and small cavity theories qualitatively predict nuclear doses for energies below and above 50 keV, respectively. Burlin's (1969) intermediate cavity theory best predicts MC results with an average discrepancy of 4%.

Conclusion:

Cellular doses vary as a function of source energy, subcellular compartment size, elemental composition, and tissue morphology. Neither water nor bulk tissue is an appropriate surrogate for subcellular targets in radiation dosimetry. The influence of microscopic inhomogeneities in the surrounding environment on the nuclear dose and the importance of the nucleus as a target for radiation‐induced cell death emphasizes the potential importance of cellular dosimetry for understanding radiation effects.

Funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Research Chairs Program (CRC), and the Ontario Ministry of Training, Colleges and Universities
WE‐EF‐BRA‐09: Microbeam Radiation Therapy Enhances Tumor Drug Uptake of PEGylated Liposomal Doxorubicin (PLD) in a Triple Negative Breast Cancer GEM Model
Authors: Chang SX , Madden AJ , Rivera JN , Santos CM , Hunter LM , Darr DB , Zamboni WC
Published: June 2015

Purpose:

Overcoming low anti‐cancer drug uptake in tumors is a key challenge limiting its clinical use. We propose to enhance the drug delivery using upfront Microbeam Radiation Therapy (MRT). MRT is a preclinical cancer therapy that utilizes microplanar beams to deliver spatially oscillating planes of high and low doses. Animal studies have demonstrated that ultrahigh dose (100s Gy) MRT eradicates tumors without damaging the function of normal tissue exposed to the same radiation. Our previous study indicated that MRT induces intense angiogenesis in tumor rim and surrounding normal tissue 1–2 days post radiation. We hypothesize that the tumor microenvironment modulation induced by MRT may enhance carrier‐mediated agent drug delivery to tumors with inherent poor drug uptake. We thus investigated MRT‐induced pharmacokinetics (PK) of PEGylated liposomal doxorubicin (PLD), a nano‐scale doxorubicin, in T11 genetically engineered mouse model of triple negative breast cancer.

Methods:

A research irradiator (160kVp, RadSource Technologies) with a customized collimator was used to produce the MRT microbeam of in average 390µm width and 1190µm peak‐to‐peak distance. The peak dose rate of 1–2Gy/min. Dosimetry is by EBT3 film cross‐calibrated with ion chamber at large fields. All mice were administered PLD at 6mg/kg IV x1 at 16h post MRT and sacrificed at 5min, 6h, 24h, and 96h post PLD administration (n=3 or 4 per group).

Results:

The MRT(28Gy)+PLD group mice had a total doxorubicin tumor concentration (area‐under‐the concentration‐curve, AUC) of 206,040ng/mL•h, 3.71 times the concentration of the PLD‐alone group. The MRT(34Gy)+PLD group had a higher mean total doxorubicin concentration in tumor (20,779ng/ml) than the MRT(28Gy)+PLD group (10,665ng/ml).

Conclusion:

Our preliminary results indicate that microbeam radiation therapy (MRT) can enhance nano‐scale anti‐cancer drug delivery to tumors approximately 4‐fold. The exact working mechanism, the comparison with broad beam irradiation, and optimization of MRT for drug delivery enhancement are under investigation.
WE‐EF‐BRA‐12: Magnetic Resonance‐ Guided High‐Intensity Focused Ultrasound for Localized Ablation of Head and Neck Tissue Structures: A Feasibility Study in An Animal Model
Authors: Partanen A , Ellens N , Noureldine S , Burdette E , Tufano R , Farahani K
Published: June 2015

Purpose:

High‐intensity focused ultrasound (HIFU) ablation is feasible in the head and neck [1]. This study aims to expand upon these findings to assess the feasibility of treatment planning and monitoring via magnetic resonance imaging (MRI) guidance using a clinical MR‐guided HIFU platform.

Methods:

Two 31 kg pigs were anaesthetized, shaved, and positioned prone on the HIFU table (Sonalleve, Philips Healthcare, Vantaa, Finland). The necks were acoustically coupled to the integrated transducer using gel pads and degassed water. MR imaging verified acoustic coupling and facilitated target selection in the thyroid and thymus. Targets were thermally ablated with 130–200 W of acoustic power over a period of 16 s at a frequency of 1.2 MHz while being monitored through real‐time, multi‐planar MR‐thermometry. Contrast‐enhanced MR imaging was used to assess treatment efficacy. Post‐treatment, animals were euthanized and sonicated tissues were harvested for histology assessment.

Results:

MR‐thermometry, post‐contrast‐imaging, and gross pathology demonstrated that the system was capable of causing localized thermal ablation in both the thyroid and the thymus without damaging the aerodigestive tract. In one animal, superficial bruising was observed in the ultrasound beam path. Otherwise, there were no adverse events. Analysis of the tissue histology found regions of damage consistent with acute thermal injury at the targeted locations.

Conclusion:

It is feasible to use a clinical MR‐guided HIFU platform for extracorporeal ablation of porcine head and neck tissues. MR guidance and thermometry are sufficient to target and monitor treatment in the thyroid region, despite the presence of the inhomogeneous aerodigestive tract. Further study is necessary to assess efficacy and survival using a tumor model, and to examine what modifications should be made to the transducer positioning system and associated patient positioning aids to adapt it for clinical head and neck targets.Reference:[1] Esnault et al. (2011). Thyroid, 21(9), 965– 973.

Funding support provided by Philips Healthcare. Ari Partanen is a paid employee of Philips Healthcare.
WE‐EF‐303‐04: An Advanced Image Processing Method to Improve the Spatial Resolution of Proton Radiographies
Authors: Rinaldi I , Parodi K , Krah N
Published: June 2015

Purpose:

We present an optimization method to improve the spatial resolution and the water equivalent thickness accuracy of proton radiographies.

Methods:

The method is designed for imaging systems measuring only the residual range of protons without relying on tracker detectors to determine the beam trajectory before and after the target. Specifically, the method was used for an imaging set‐up consisting of a stack of 61 parallel‐plate ionization chambers (PPIC) working as a range telescope. The method uses a decomposition approach of the residual range signal measured by the PPIC and constructs subimages with small size pixels geometrically rearranged and appropriately averaged to be merged into a final single radiography. The method was tested using Monte Carlo simulated and experimental proton radiographies of a PMMA step phantom and an anthropomorphic head phantom.

Results:

For the step phantom, the effective spatial resolution was found to be 4 and 3 times higher than the nominal resolution for the simulated and experimental radiographies, respectively. For the head phantom, a gamma index was calculated to quantify the conformity of the simulated proton radiographies with a digitally reconstructed X‐ray radiography convolved with a Gaussian kernel equal to the proton beam spot‐size. For DTA=2.5 mm and RD=2.5%, the passing ratio was 100%/85% for the optimized/non‐optimized case, respectively. An extension of the method allows reducing the dose given to the patient during radiography acquisition. We show that despite a dose reduction of 25 times (leading to a dose of 0.016 mGy for the current imaging set‐up), the image quality of the optimized radiographies remains fairly unaffected for both the simulated and experimental results.

Conclusion:

The optimization method leads to a significant increase of the spatial resolution allowing recovering image details that are unresolved in non‐optimized radiographies. These results represent a major step towards clinical application of proton radiography.
WE‐EF‐303‐07: Imaging of Prompt Gamma Rays Emitted During Delivery of Clinical Proton Beams with a Compton Camera: Feasibility Studies for Range Verification
Authors: Polf J , Avery S , Mackin D , Beddar S
Published: June 2015

Purpose:

Evaluation of a prototype Compton camera (CC) for imaging prompt gamma rays (PG) emitted during clinical proton beam irradiation for in vivo beam range verification.

Methods:

We irradiated a water phantom with 114 MeV and 150 MeV proton pencil beams at clinical beam currents ranging from 1 nA up to 5 nA. The CC was placed 15 cm from the beam central axis and PGs from 0.2 MeV up to 6.5 MeV were measured during irradiation. From the measured data, 2‐dimensional (2D) PG images were reconstructed. One‐dimensional (1D) profiles from the PG images were compared to measured depth dose curves.

Results:

The CC was able to measure PG emission during delivery of both a single 150 MeV pencil beam and a 5 cm × 5 cm mono‐energetic layer of 114 MeV pencil beams. From the 2D images, a strong correlation was seen between the depth of the distal falloff of PG emission and the Bragg peak (BP). 1D profiles extracted from the PG images show that the distal 60% falloff of the PG emission lined up well with the distal 90% of the BP. Shifts as small as 3 mm in the beam range could be detected on both the 2D PG images and 1D profiles with an uncertainty of 1.5 mm. With the current CC prototype, a minimum dose delivery of 400 cGy was required to produce usable PG images.

Conclusions:

It was possible to measure and image PG emission with our prototype CC during proton beam delivery and to detect shifts in the BP range in the images. Therefore prompt gamma imaging with a CC for the purpose of in vivo range verification is feasible. However, for the studied system improvements in detector efficiency and reconstruction algorithms are necessary to make it clinically viable.
WE‐EF‐303‐10: Single‐ Detector Proton Radiography as a Portal Imaging Equivalent for Proton Therapy
Authors: Doolan P , Bentefour E , Testa M , Cascio E , Royle G , Gottschalk B , Lu H
Published: June 2015

Purpose:

In proton therapy, patient alignment is of critical importance due to the sensitivity of the proton range to tissue heterogeneities. Traditionally proton radiography is used for verification of the water‐equivalent path length (WEPL), which dictates the depth protons reach. In this work we propose its use for alignment. Additionally, many new proton centers have cone‐beam computed tomography in place of beamline X‐ray imaging and so proton radiography offers a unique patient alignment verification similar to portal imaging in photon therapy.

Method:

Proton radiographs of a CIRS head phantom were acquired using the Beam Imaging System (BIS) (IBA, Louvain‐la‐Neuve) in a horizontal beamline. A scattered beam was produced using a small, dedicated, range modulator (RM) wheel fabricated out of aluminum. The RM wheel was rotated slowly (20 sec/rev) using a stepper motor to compensate for the frame rate of the BIS (120 ms). Dose rate functions (DRFs) over two RM wheel rotations were acquired. Calibration was made with known thicknesses of homogeneous solid water. For each pixel the time width, skewness and kurtosis of the DRFs were computed. The time width was used to compute the object WEPL. In the heterogeneous phantom, the excess skewness and excess kurtosis (i.e. difference from homogeneous cases) were computed and assessed for suitability for patient set up.

Results:

The technique allowed for the simultaneous production of images that can be used for WEPL verification, showing few internal details, and excess skewness and kurtosis images that can be used for soft tissue alignment. These latter images highlight areas where range mixing has occurred, correlating with phantom heterogeneities.

Conclusion:

The excess skewness and kurtosis images contain details that are not visible in the WET images. These images, unique to the time‐resolved proton radiographic method, could be used for patient set up according to soft tissues.
WE‐EF‐204‐03: Strategies for Synergizing Pre‐Clinical and Clinical Acquisition for Future Co‐Clinical Trials
Authors: Keshari K.
Published: June 2015

As molecular biology breakthroughs in understanding cancers and other diseases, hundreds of new drugs wait testing. In the last decade, mouse models have been evolved to better mimic human diseases genetically and biologically. These reliable mouse models allow us to determine which genetic elements, pathways and mutations impact on therapy. The co‐clinical trial strategy is to conduct a human clinical trial for a therapeutic drug and test it in mouse models at the same time. This strategy has the potential to accelerate the drug testing process and identify the patient population that will respond to the drug. Imaging plays an important role in co‐clinical trials. In this symposium, four speakers will discuss advancements and issues in pre‐clinical imaging, murine models, imaging hardware and software, and funding opportunities in co‐clinical trials.

Learning Objectives:

Multi‐modality pre‐clinical imaging hardware and software, and new technologies (e.g., hyperpolarized MRI)

Selection of animal models from physiological and genetic perspectives with examples in colon, pancreatic and lung cancers

NCI funding opportunities
WE‐EF‐204‐04: NCI Interest in Promoting Best Practices for Co‐Clinical Trials
Authors: Clarke L.
Published: June 2015

As molecular biology breakthroughs in understanding cancers and other diseases, hundreds of new drugs wait testing. In the last decade, mouse models have been evolved to better mimic human diseases genetically and biologically. These reliable mouse models allow us to determine which genetic elements, pathways and mutations impact on therapy. The co‐clinical trial strategy is to conduct a human clinical trial for a therapeutic drug and test it in mouse models at the same time. This strategy has the potential to accelerate the drug testing process and identify the patient population that will respond to the drug. Imaging plays an important role in co‐clinical trials. In this symposium, four speakers will discuss advancements and issues in pre‐clinical imaging, murine models, imaging hardware and software, and funding opportunities in co‐clinical trials.

Learning Objectives:

Multi‐modality pre‐clinical imaging hardware and software, and new technologies (e.g., hyperpolarized MRI)

Selection of animal models from physiological and genetic perspectives with examples in colon, pancreatic and lung cancers

NCI funding opportunities
WE‐EF‐207‐02: The Rotate‐Plus‐Shift C‐Arm Trajectory: Theory and First Clinical Results
Authors: Ritschl L , Kachelriess M , Kuntz J
Published: June 2015

Purpose:

The proposed method enables the acquisition of a complete dataset for 3D reconstruction of C‐Arm data using less than 180° rotation.

Methods:

Typically a C–arm cone–beam CT scan is performed using a circle–like trajectory around a region of interest. Therefore an angular range of at least 180° plus fan–angle must be covered to ensure a completely sampled data set. This fact defines some constraints on the geometry and technical specifications of a C–arm system, for example a larger C radius or a smaller C opening respectively. This is even more important for mobile C‐arm devices which are typically used in surgical applications.To overcome these limitations we propose a new trajectory which requires only 180° minusfan–angle of rotation for a complete data set. The trajectory consists of three parts: A rotation of the C around a defined iso–center and two translational movements parallel to the detector plane at the begin and at the end of the rotation (rotate plus shift trajectory). This enables the acquisition of a completely sampled dataset using only 180° minus fan–angle of rotation.

Results:

For the evaluation of the method we show simulated and measured data. The results show, that the rotate plus shift scan yields equivalent image quality compared to the short scan which is assumed to be the gold standard for C‐arm CT today. Compared to the pure rotational scan over only 165°, the rotate plus shift scan shows strong improvements in image quality.

Conclusion:

The proposed method makes 3D imaging using C–arms with less than 180° rotation range possible. This enables integrating full 3D functionality into a C‐ arm device without any loss of handling and usability for 2D imaging.
WE‐EF‐207‐03: Design and Optimization of a CBCT Head Scanner for Detection of Acute Intracranial Hemorrhage
Authors: Xu J , Sisniega A , Zbijewski W , Dang H , Stayman J , Wang X , Foos DH , Aygun N , Koliatsos V , Siewerdsen JH
Published: June 2015

Purpose:

To design a dedicated x‐ray cone‐beam CT (CBCT) system suitable to deployment at the point‐of‐care and offering reliable detection of acute intracranial hemorrhage (ICH), traumatic brain injury (TBI), stroke, and other head and neck injuries.

Methods:

A comprehensive task‐based image quality model was developed to guide system design and optimization of a prototype head scanner suitable to imaging of acute TBI and ICH. Previously reported models were expanded to include the effects of x‐ray scatter correction necessary for detection of low contrast ICH and the contribution of bit depth (digitization noise) to imaging performance. Task‐based detectablity index provided the objective function for optimization of system geometry, x‐ray source, detector type, anti‐scatter grid, and technique at 10–25 mGy dose. Optimal characteristics were experimentally validated using a custom head phantom with 50 HU contrast ICH inserts imaged on a CBCT imaging bench allowing variation of system geometry, focal spot size, detector, grid selection, and x‐ray technique.

Results:

The model guided selection of system geometry with a nominal source‐detector distance 1100 mm and optimal magnification of 1.50. Focal spot size ∼0.6 mm was sufficient for spatial resolution requirements in ICH detection. Imaging at 90 kVp yielded the best tradeoff between noise and contrast. The model provided quantitation of tradeoffs between flat‐panel and CMOS detectors with respect to electronic noise, field of view, and readout speed required for imaging of ICH. An anti‐scatter grid was shown to provide modest benefit in conjunction with post‐acquisition scatter correction. Images of the head phantom demonstrate visualization of millimeter‐scale simulated ICH.

Conclusions:

Performance consistent with acute TBI and ICH detection is feasible with model‐based system design and robust artifact correction in a dedicated head CBCT system. Further improvements can be achieved with incorporation of model‐based iterative reconstruction techniques also within the scope of the task‐based optimization framework.

David Foos and Xiaohui Wang are employees of Carestream Health
WE‐E‐201‐00: Practical Statistics for Medical Physicists
Authors: Sensakovic William
Published: June 2015

Physicists are often expected to have a solid grounding in experimental design and statistical analysis, sometimes filling in when biostatisticians or other experts are not available for consultation. Unfortunately, graduate education on these topics is seldom emphasized and few opportunities for continuing education exist. Clinical physicists incorporate new technology and methods into their practice based on published literature. A poor understanding of experimental design and analysis could Result in inappropriate use of new techniques. Clinical physicists also improve current practice through quality initiatives that require sound experimental design and analysis. Academic physicists with a poor understanding of design and analysis may produce ambiguous (or misleading) results. This can Result in unnecessary rewrites, publication rejection, and experimental redesign (wasting time, money, and effort).

This symposium will provide a practical review of error and uncertainty, common study designs, and statistical tests. Instruction will primarily focus on practical implementation through examples and answer questions such as: where would you typically apply the test/design and where is the test/design typically misapplied (i.e., common pitfalls)? An analysis of error and uncertainty will also be explored using biological studies and associated modeling as a specific use case.

Learning Objectives:

Understand common experimental testing and clinical trial designs, what questions they can answer, and how to interpret the results

Determine where specific statistical tests are appropriate and identify common pitfalls

Understand the how uncertainty and error are addressed in biological testing and associated biological modeling.
WE‐E‐201‐01: Use and Abuse of Common Statistics in Radiological Physics
Authors: Labby Z.
Published: June 2015

Physicists are often expected to have a solid grounding in experimental design and statistical analysis, sometimes filling in when biostatisticians or other experts are not available for consultation. Unfortunately, graduate education on these topics is seldom emphasized and few opportunities for continuing education exist. Clinical physicists incorporate new technology and methods into their practice based on published literature. A poor understanding of experimental design and analysis could Result in inappropriate use of new techniques. Clinical physicists also improve current practice through quality initiatives that require sound experimental design and analysis. Academic physicists with a poor understanding of design and analysis may produce ambiguous (or misleading) results. This can Result in unnecessary rewrites, publication rejection, and experimental redesign (wasting time, money, and effort).

This symposium will provide a practical review of error and uncertainty, common study designs, and statistical tests. Instruction will primarily focus on practical implementation through examples and answer questions such as: where would you typically apply the test/design and where is the test/design typically misapplied (i.e., common pitfalls)? An analysis of error and uncertainty will also be explored using biological studies and associated modeling as a specific use case.

Learning Objectives:

Understand common experimental testing and clinical trial designs, what questions they can answer, and how to interpret the results

Determine where specific statistical tests are appropriate and identify common pitfalls

Understand the how uncertainty and error are addressed in biological testing and associated biological modeling.
WE‐EF‐210‐08: BEST IN PHYSICS (IMAGING): 3D Prostate Segmentation in Ultrasound Images Using Patch‐Based Anatomical Feature
Authors: Yang X , Rossi P , Jani A , Ogunleye T , Curran W , Liu T
Published: June 2015

Purpose:

Transrectal ultrasound (TRUS) is the standard imaging modality for the image‐guided prostate‐cancer interventions (e.g., biopsy and brachytherapy) due to its versatility and real‐time capability. Accurate segmentation of the prostate plays a key role in biopsy needle placement, treatment planning, and motion monitoring. As ultrasound images have a relatively low signal‐to‐noise ratio (SNR), automatic segmentation of the prostate is difficult. However, manual segmentation during biopsy or radiation therapy can be time consuming. We are developing an automated method to address this technical challenge.

Methods:

The proposed segmentation method consists of two major stages: the training stage and the segmentation stage. During the training stage, patch‐based anatomical features are extracted from the registered training images with patient‐specific information, because these training images have been mapped to the new patient’ images, and the more informative anatomical features are selected to train the kernel support vector machine (KSVM). During the segmentation stage, the selected anatomical features are extracted from newly acquired image as the input of the well‐trained KSVM and the output of this trained KSVM is the segmented prostate of this patient.

Results:

This segmentation technique was validated with a clinical study of 10 patients. The accuracy of our approach was assessed using the manual segmentation. The mean volume Dice Overlap Coefficient was 89.7±2.3%, and the average surface distance was 1.52 ± 0.57 mm between our and manual segmentation, which indicate that the automatic segmentation method works well and could be used for 3D ultrasound‐guided prostate intervention.

Conclusion:

We have developed a new prostate segmentation approach based on the optimal feature learning framework, demonstrated its clinical feasibility, and validated its accuracy with manual segmentation (gold standard). This segmentation technique could be a useful tool for image‐guided interventions in prostate‐cancer diagnosis and treatment.

This research is supported in part by DOD PCRP Award W81XWH‐13‐1‐0269, and National Cancer Institute (NCI) Grant CA114313.
WE‐F‐213‐00: Building, Maintaining and Improving Physics Residency Programs
Authors: Klein Eric
Published: June 2015

In this session we will discuss the key steps for building, maintaining and improving a physics residency program. The initial momentum starts with a secure commitment of; a program director, physics faculty, physicians, key technical personnel, and, of course, administration. The ultimate goal is to build a strong clinical physicist who practice independently and/or work in an interdisciplinary team. Part of the initiation is to find out the right balance of training, resident empowerment, and service contributed back to the clinic.

Another key step that will be discussed is the recruitment of resident candidates. Namely, where the residents are coming from, what their educational background is, and most importantly during interviews, how to gauge what makes an ideal resident. Experiences on the first year of Medphys Match will be shared as well as strategies for placement following graduation.

The key to maintenance of a residency program is to not allow stagnation, but rather to constantly update. Examples will be given of evolution of programs in terms of the didactic and clinical rotational components. In addition, how to allocate the resident developmental work, whether it be clinical or benchmark, without disrupting training. We will also discuss how to evaluate faculty on the ownership they take regarding resident training. We will discuss both therapy and imaging programs.

Finally, we will share experiences on steps to continually improve one's program.

Learning Objectives:

To obtain from the experience of long standing programs the lessons learned.

To find out what historically has worked out to be ideal resident candidates.

Guidelines for continually improving a program.
WE‐F‐304‐00: Outcomes of Hypofractionated Treatments ‐ Results of the WGSBRT
Authors: Grimm Jimm
Published: June 2015

Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT's work for cranial sites, and recurrent head and neck cancer. From literature‐based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear‐quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer‐reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes.

1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose‐volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60.

Learning Objectives:

Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT

List the radiobiological models that compete with the linear‐quadratic model in explaining the results of hypofractionated RT

Describe the dose/volume metrics that are considered safe in SBRT treatment of tumors near the optic structures.

Discuss the efficacy of hypofractionation and dosing schedules used in treating vestibular schwannomas

Identify some difficulties in modeling TCP and NTCP for cranial tumors treated with hypofractionation.

One moderator, Dr. Grimm, designed and holds intellectual property rights to the DVH Evaluator software tool which is an FDA‐cleared product in commercial use, and can analyze some of this data.

No others have relevant conflicts of interest.
WE‐F‐304‐01: Overview of the Working Group On Stereotactic Body Radiation Therapy (WGSBRT)
Authors: Yorke E.
Published: June 2015

Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT's work for cranial sites, and recurrent head and neck cancer. From literature‐based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear‐quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer‐reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes.

1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose‐volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60.

Learning Objectives:

Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT

List the radiobiological models that compete with the linear‐quadratic model in explaining the results of hypofractionated RT

Describe the dose/volume metrics that are considered safe in SBRT treatment of tumors near the optic structures.

Discuss the efficacy of hypofractionation and dosing schedules used in treating vestibular schwannomas

Identify some difficulties in modeling TCP and NTCP for cranial tumors treated with hypofractionation.

One moderator, Dr. Grimm, designed and holds intellectual property rights to the DVH Evaluator software tool which is an FDA‐cleared product in commercial use, and can analyze some of this data.

No others have relevant conflicts of interest.
WE‐F‐304‐03: Optic Nerve/Chiasm Hypofractionated SRS/SRT Dose Tolerance
Authors: Milano M.
Published: June 2015

Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT's work for cranial sites, and recurrent head and neck cancer. From literature‐based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear‐quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer‐reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes.

1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose‐volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60.

Learning Objectives:

Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT

List the radiobiological models that compete with the linear‐quadratic model in explaining the results of hypofractionated RT

Describe the dose/volume metrics that are considered safe in SBRT treatment of tumors near the optic structures.

Discuss the efficacy of hypofractionation and dosing schedules used in treating vestibular schwannomas

Identify some difficulties in modeling TCP and NTCP for cranial tumors treated with hypofractionation.

One moderator, Dr. Grimm, designed and holds intellectual property rights to the DVH Evaluator software tool which is an FDA‐cleared product in commercial use, and can analyze some of this data.

No others have relevant conflicts of interest.
WE‐F‐304‐04: Radiosurgery for Vestibular Schwannomas: Tumor Control Probability Analyses and Recommended Reporting Standards
Authors: Soltys S.
Published: June 2015

Stereotactic Body Radiation Therapy (SBRT) was introduced clinically more than twenty years ago, and many subsequent publications have reported safety and efficacy data. The AAPM Working Group on Biological Effects of Hypofractionated Radiotherapy/SBRT (WGSBRT) extracted published treatment outcomes data from extensive literature searches to summarize and construct tumor control probability (TCP) and normal tissue complication probability (NTCP) models for six anatomical regions: Cranial, Head and Neck, Thoracic, Abdominal, Pelvic, and Spinal. In this session, we present the WGSBRT's work for cranial sites, and recurrent head and neck cancer. From literature‐based data and associated models, guidelines to aid with safe and effective hypofractionated radiotherapy treatment are being determined. Further, the ability of existing and proposed radiobiological models to fit these data is considered as to the ability to distinguish between the linear‐quadratic and alternative radiobiological models such as secondary cell death from vascular damage, immunogenic, or bystander effects. Where appropriate, specific model parameters are estimated. As described in “The lessons of QUANTEC,” (1), lack of adequate reporting standards continues to limit the amount of useful quantitative information that can be extracted from peer‐reviewed publications. Recommendations regarding reporting standards are considered, to enable such reviews to achieve more complete characterization of clinical outcomes.

1 Jackson A, Marks LB, Bentzen SM, Eisbruch A, Yorke ED, Ten Haken RK, Constine LS, Deasy JO. The lessons of QUANTEC: recommendations for reporting and gathering data on dose‐volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys. 2010 Mar 1;76(3 Suppl):S155–60.

Learning Objectives:

Describe the techniques, types of cancer and dose schedules used in treating recurrent H&N cancers with SBRT

List the radiobiological models that compete with the linear‐quadratic model in explaining the results of hypofractionated RT

Describe the dose/volume metrics that are considered safe in SBRT treatment of tumors near the optic structures.

Discuss the efficacy of hypofractionation and dosing schedules used in treating vestibular schwannomas

Identify some difficulties in modeling TCP and NTCP for cranial tumors treated with hypofractionation.

One moderator, Dr. Grimm, designed and holds intellectual property rights to the DVH Evaluator software tool which is an FDA‐cleared product in commercial use, and can analyze some of this data.

No others have relevant conflicts of interest.
WE‐F‐BRB‐00: New Developments in Knowledge‐Based Treatment Planning and Automation
Authors: McNutt Todd
Published: June 2015

Advancements in informatics in radiotherapy are opening up opportunities to improve our ability to assess treatment plans. Models on individualizing patient dose constraints from prior patient data and shape relationships have been extensively researched and are now making their way into commercial products. New developments in knowledge based treatment planning involve understanding the impact of the radiation dosimetry on the patient. Akin to radiobiology models that have driven intensity modulated radiotherapy optimization, toxicity and outcome predictions based on treatment plans and prior patient experiences may be the next step in knowledge based planning. In order to realize these predictions, it is necessary to understand how the clinical information can be captured, structured and organized with ontologies and databases designed for recall. Large databases containing radiation dosimetry and outcomes present the opportunity to evaluate treatment plans against predictions of toxicity and disease response. Such evaluations can be based on dose volume histogram or even the full 3‐dimensional dose distribution and its relation to the critical anatomy.

This session will provide an understanding of ontologies and standard terminologies used to capture clinical knowledge into structured databases; How data can be organized and accessed to utilize the knowledge in planning; and examples of research and clinical efforts to incorporate that clinical knowledge into planning for improved care for our patients.

Learning Objectives:

Understand the role of standard terminologies, ontologies and data organization in oncology

Understand methods to capture clinical toxicity and outcomes in a clinical setting

Understand opportunities to learn from clinical data and its application to treatment planning

Todd McNutt receives funding from Philips, Elekta and Toshiba for some of the work presented
WE‐G‐304‐01: Introduction
Authors: Starkschall G.
Published: June 2015

In the past few years, several high‐profile medical physicists found their positions terminated. It is a fact that no medical physics job is a sinecure, and that individuals can be terminated through no fault of their own. Medical physicists need to be prepared for such an occurrence. Termination provisions in an employment contract, whether individually negotiated or as part of an employee manual, are important, and also generally overlooked when one is going into a new job. Coupled with the fact that most states are “at‐will,” that makes for a tough position for any physicist who finds his/her position terminated.

In this course, a medical physicist who is also a practicing attorney will start the discussion with a description of the various types of employment situations and employment agreements. This will be followed by two high‐profile medical physicists who had their positions terminated in recent years, who will describe their experiences, including answering such questions as

How much time were you given before termination was effective?

Did you have any foreshadowing of what was coming?

How did you deal with the termination?

Given hindsight, what would you have done differently to mitigate the effects of your termination?

During job interviews, are there ways to open closets to find the skeletons?

What advice would you give medical physicists if faced with a similar situation?

What can you negotiate in a termination agreement?

What kinds of termination agreements could be presented?

The symposium will conclude with a panel discussion.

Learning Objectives:

Identify the various types of employment contracts with an emphasis on termination provisions.

Recognize the implications of non‐compete clauses in employment contracts.

Recognize the possibility of termination of employment.

Identify ways to recognize possibly poor employment situations

Identify steps that one could take to mitigate the effects of termination.
WE‐G‐304‐04: My Personal Experience
Authors: Grant W.
Published: June 2015

In the past few years, several high‐profile medical physicists found their positions terminated. It is a fact that no medical physics job is a sinecure, and that individuals can be terminated through no fault of their own. Medical physicists need to be prepared for such an occurrence. Termination provisions in an employment contract, whether individually negotiated or as part of an employee manual, are important, and also generally overlooked when one is going into a new job. Coupled with the fact that most states are “at‐will,” that makes for a tough position for any physicist who finds his/her position terminated.

In this course, a medical physicist who is also a practicing attorney will start the discussion with a description of the various types of employment situations and employment agreements. This will be followed by two high‐profile medical physicists who had their positions terminated in recent years, who will describe their experiences, including answering such questions as

How much time were you given before termination was effective?

Did you have any foreshadowing of what was coming?

How did you deal with the termination?

Given hindsight, what would you have done differently to mitigate the effects of your termination?

During job interviews, are there ways to open closets to find the skeletons?

What advice would you give medical physicists if faced with a similar situation?

What can you negotiate in a termination agreement?

What kinds of termination agreements could be presented?

The symposium will conclude with a panel discussion.

Learning Objectives:

Identify the various types of employment contracts with an emphasis on termination provisions.

Recognize the implications of non‐compete clauses in employment contracts.

Recognize the possibility of termination of employment.

Identify ways to recognize possibly poor employment situations

Identify steps that one could take to mitigate the effects of termination.
WE‐G‐BRD‐05: Inline Magnetic Fields Enhance Tumor Dose for Small Lung Cancers
Authors: Oborn B , Ge Y , Hardcastle N , Metcalfe P , Keall P
Published: June 2015

Purpose:

To report on significant dose enhancement effects caused by magnetic fields aligned parallel to 6MV photon beam radiotherapy of small lung tumors. Findings are applicable to future inline MRI‐guided radiotherapy systems.

Methods:

9 clinical lung plans were recalculated using Monte Carlo methods and external inline (parallel to the beam direction) magnetic fields of 0.5 T, 1.0 T and 3 T were included. Three plans were 6MV 3D‐CRT and six were 6MV IMRT. The GTV's ranged from 0.8 cc to 73 cc, while the PTV ranged from 1 cc to 180 cc.

Results:

The inline magnetic field has a moderate impact in lung dose distributions by reducing the lateral scatter of secondary electrons and causing a small local dose increase. Superposition of multiple small beams acts to superimpose the small dose increases and can lead to significant dose enhancements, especially when the GTV is low density. Two plans with very small, low mean density GTV's (<1 cc, ρ(mean)<0.35g/cc) showed uniform increases of 16% and 23% at 1 T throughout the PTV. Three plans with moderate mean density PTV's (3–13 cc, ρ(mean)=0.58–0.67 g/cc) showed 6% mean dose enhancement at 1 T in the PTV, however not uniform throughout the GTV/PTV. Replanning would benefit these cases. The remaining 5 plans had large dense GTV's (∼ 1 g/cc) and so only a minimal (<2%) enhancement was seen. In general the mean dose enhancement at 0.5 T was 60% less than 1 T, while 5–50% higher at 3 T.

Conclusions:

A paradigm shift in the efficacy of small lung tumor radiotherapy is predicted with future inline MRI‐linac systems. This will be achieved by carefully taking advantage of the reduction of lateral electronic disequilibrium withing lung tissue that is induced naturally inside strong inline magnetic fields.
WE‐G‐BRB‐03: Innovating the Delivery of Radiation Therapy
Authors: Bortfeld T.
Published: June 2015

Over the past 20 years the NIH has funded individual grants, program projects grants, and clinical trials which have been instrumental in advancing patient care. The ways that each grant mechanism lends itself to the different phases of translating research into clinical practice will be described. Major technological innovations, such as IMRT and proton therapy, have been advanced with R01‐type and P01‐type funding and will be discussed. Similarly, the role of program project grants in identifying and addressing key hypotheses on the potential of 3D conformal therapy, normal tissue‐guided dose escalation and motion management will be described. An overview will be provided regarding how these technological innovations have been applied to multi‐institutional NIH‐sponsored trials. Finally, the panel will discuss regarding which research questions should be funded by the NIH to inspire the next advances in radiation therapy.

Learning Objectives:

Understand the different funding mechanisms of the NIH

Learn about research advances that have led to innovation in delivery

Review achievements due to NIH‐funded program project grants in radiotherapy over the past 20 years

Understand example advances achieved with multi‐institutional clinical trials

NIH