bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐EF‐207‐11: Energy and Depth Response of Thermoluminescent Dosimeters and Ionization Chambers in Water for Kilovoltage X‐Ray Beams
Authors: Lawless M , Palmer B , DeWerd L 
Published: June 2015

Purpose:To assess the effects of changes in beam quality on detector response in the kilovoltage energy range by modulating the x‐ray tube voltage and the measurement depth in water.Methods:Measurements were performed with TLD‐100 and TLD‐100H thermoluminescent dosimeters and an A12 farmer‐type ionization chamber. To assess the energy response of the detectors, irradiations were performed at a depth of 3 cm in a custom‐built thin‐window water phantom using the moderately filtered x‐ray beams at the UWADCL (20 kVp‐250 kVp) and a Co‐60 beam.The x‐ray beams and detectors were modeled using the EGSnrc Monte Carlo code. The model was validated by simulating dose to the collecting volume of an A12 farmer chamber and comparing it with measured A12 signal as a function of depth. Dose was tallied to each detector and to water for comparison with measurements. Simulations were used to calculate the predicted energy response, which was compared to the measured response of each detector. Dose to each detector and dose to water as a function of depth were also simulated.Results:Detector output per dose to water was found to deviate by up to 15%, 20% and 30% as a function of energy relative to Co‐60 for the A12, TLD‐100H and TLD‐100, respectively. The EGSnrc simulations produced results similar to the measurements for ionization chambers, but discrepancies of up to 30% were observed for TLD‐100H. Simulated detector response as a function of depth was found to vary by up to 3%.Conclusion:These results suggest that changes in beam quality in kilovoltage x‐ray beams can have a significant impact on detector response. In‐water detector response was found to differ from the previously investigated in‐air response. Deviations in detector response as a function of depth were less significant, but could potentially cause dosimetric errors if ignored.
WE‐E‐201‐02: Phases, Levels, Controls, and All That: An Informal Session On Clinical Trials
Authors: Hipp E. 
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‐210‐01: Advances in Coherent Image Formation and Volume Imaging in Ultrasound
Authors: Rao B. 
Published: June 2015

Recent advances in ultrasound‐related technologies have had a significant impact on enhancing image quality as well as offering new approaches for quantitative ultrasonic imaging and therapeutic applications. The presentations associated with this session will provide an overview of advances in ultrasound image formation, the development of using nanoparticles for therapeutic ultrasound applications, as well as approaches for assessing the intrinsic viscoelastic properties of tissue and methods for monitoring tissue response to therapy.Learning Objectives:

Develop a general understanding of new technologies associated with enhanced ultrasound image formation and volume imaging.
Develop an understanding of new ultrasound‐based technologies for quantitative assessment of intrinsic tissue properties.
Develop an understanding of novel approaches for ultrasound‐mediated non‐invasive therapeutic applications.
Dr. Rao is an employee of Siemens Ultrasound
WE‐EF‐210‐05: Diagnosis and Quantification of Liver Steatosis with Quantitative Ultrasound Backscatter Technique
Authors: Andre M , Heba E , Han A , Lin S , Wolfson T , Ang B , Gamst A , Erdman J , O'Brien W , Sirlin C , Loomba R 
Published: June 2015

Purpose:Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the United States, affects 30% of adult Americans and may progress to more serious diseases. Liver biopsy is the standard method for diagnosing NAFLD. MRI can accurately diagnose and quantify hepatic steatosis but is expensive. Sonography with qualitative interpretation by radiologists is lower cost, more accessible but less sensitive for detection. The objective of this study, using MRI proton density fat fraction (PDFF) as reference, is to assess the accuracy for diagnosing and quantifying steatosis with two quantitative US parameters‐‐ backscatter coefficient (BSC) and attenuation coefficient (AC)‐‐derived from RF signals using the calibration phantom technique.Methods:We performed a prospective, cross‐sectional analysis of a cohort of adults (n=204) with NAFLD (MRI‐PDFF≥5%) and without NAFLD (controls). Subjects underwent MRI‐PDFF and BSC and AC US analyses of the liver on the same day. Patients were randomly assigned to training (n=102, mean age 51±17 years, mean body mass index 31±7 kg/m2) and validation (n=102, mean age 49±17 years, body mass index 30±6 kg/m2) groups; 69% of patients in each group had NAFLD.Results:BSC provided AUC 0.98 (95% CI 0.95–1.00, p<0.0001) for diagnosis of NAFLD; the optimal BSC cut‐off provided sensitivity, specificity, positive and negative predictive values (PPV, NPV) of 87%, 91%, 95%, and 76%, respectively. AC provided AUC 0.89 (95% CI 0.81–0.96, p<0.0001) for diagnosis of steatosis; the optimal AC cut‐off provided sensitivity, specificity, PPV, NPV of 80%, 84%, 92%, and 66%, respectively. BSC and AC both correlated significantly with MRI‐PDFF (P<0.0001).Conclusion:QUS BSC and AC can accurately diagnose and quantify hepatic steatosis, using MRI‐PDFF as reference. With further validation, QUS may emerge as an inexpensive, widely available tool for NAFLD assessment.General support: NIH R01 CA111289, K23 ‐DK090303, AmerGastroAssoc Found, TF Williams Scholarship, S3000 scanner loaned by Siemens, Sucampo, JA Hartford Found, Atlantic Philanthropies Amer Gastroenterological Assoc. Agencies had no role in design/conduct of study, collection, management, analysis or interpretation of the data; preparation, review, or approval of the manuscript.
WE‐EF‐210‐06: Ultrasound 2D Strain Measurement of Radiation‐Induced Toxicity: Phantom and Ex Vivo Experiments
Authors: Liu T , Torres M , Rossi P , Jani A , Curran W , Yang X 
Published: June 2015

Purpose:Radiation‐induced fibrosis is a common long‐term complication affecting many patients following cancer radiotherapy. Standard clinical assessment of subcutaneous fibrosis is subjective and often limited to visual inspection and palpation. Ultrasound strain imaging describes the compressibility (elasticity) of biological tissues. This study's purpose is to develop a quantitative ultrasound strain imaging that can consistently and accurately characterize radiation‐induce fibrosis.Methods:In this study, we propose a 2D strain imaging method based on deformable image registration. A combined affine and B‐spline transformation model is used to calculate the displacement of tissue between pre‐stress and post‐stress B‐mode image sequences. The 2D displacement is estimated through a hybrid image similarity measure metric, which is a combination of the normalized mutual information (NMI) and normalized sum‐of‐squared‐differences (NSSD). And 2D strain is obtained from the gradient of the local displacement. We conducted phantom experiments under various compressions and compared the performance of our proposed method with the standard cross‐correlation (CC)‐ based method using the signal‐to‐noise (SNR) and contrast‐to‐noise (CNS) ratios. In addition, we conducted ex‐vivo beef muscle experiment to further validate the proposed method.Results:For phantom study, the SNR and CNS values of the proposed method were significantly higher than those calculated from the CC‐based method under different strains. The SNR and CNR increased by a factor of 1.9 and 2.7 comparing to the CC‐based method. For the ex‐vivo experiment, the CC‐based method failed to work due to large deformation (6.7%), while our proposed method could accurately detect the stiffness change.Conclusion:We have developed a 2D strain imaging technique based on the deformable image registration, validated its accuracy and feasibility with phantom and ex‐vivo data. This 2D ultrasound strain imaging technology may be valuable as physicians try to eliminate radiation‐induce fibrosis and improve the therapeutic ratio of cancer radiotherapy.This research is supported in part by DOD PCRP Award W81XWH‐13‐1‐0269, and National Cancer Institute (NCI) Grant CA114313.
WE‐EF‐210‐07: Development of a Minimally Invasive Photo Acoustic Imaging System for Early Prostate Cancer Detection
Authors: Sano M , Yousefi S , Xing L 
Published: June 2015

Purpose:The objective of this work is to design, implement and characterize a catheter‐based ultrasound/photoacoustic imaging probe for early‐diagnosis of prostate cancer and to aid in image‐guided radiation therapy.Methods:The need to image across 6–10cm of tissue to image the whole prostate gland limits the resolution achievable with a transrectal ultrasound approach. In contrast, the urethra bisects the prostate gland, providing a minimally invasive pathway for deploying a high resolution ultrasound transducer. Utilizing a high‐frequency (20MHz) ultrasound/photoacoustic probe, high‐resolution structural and molecular imaging of the prostate tissue is possible. A custom 3D printed probe containing a high‐frequency single‐element ultrasound transducer is utilized. The diameter of the probe is designed to fit inside a Foley catheter and the probe is rotated around the central axis to achieve a circular B‐scan. A custom ultrasound amplifier and receiver was set up to trigger the ultrasound pulse transmission and record the reflected signal. The reconstructed images were compared to images generated by traditional 5 MHz ultrasound transducers.Results:The preliminary results using the high‐frequency ultrasound probe show that it is possible to resolve finely detailed information in a prostate tissue phantom that was not achievable with previous low‐frequency ultrasound systems. Preliminary ultrasound imaging was performed on tissue mimicking phantom and sensitivity and signal‐to‐noise ratio of the catheter was measured.Conclusion:In order to achieve non‐invasive, high‐resolution, structural and molecular imaging for early‐diagnosis and image‐guided radiation therapy of the prostate tissue, a transurethral catheter was designed. Structural/molecular imaging using ultrasound/photoacoustic of the prostate tissue will allow for localization of hyper vascularized areas for early‐stage prostate cancer diagnosis.
WE‐F‐304‐05: Cranial TCP/NTCP Modeling Insights and Caveats
Authors: El Naqa I. 
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‐213‐01: Building, Maintaining and Improving Physics Residency Programs
Authors: Klein E. 
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‐213‐02: Building, Maintaining and Improving Physics Residency Programs
Authors: Nye J. 
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‐304‐02: Recurrent HNC Treated with SBRT: TCP‐Based Outcome Estimates
Authors: Clump D. 
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‐02: Setting the Stage for Incorporation of Toxicity Measures in Treatment Plan Assessments
Authors: Mayo C. 
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