bluuebunny/crossref_metadata_2025 huggingface dataset:
TU‐AB‐209‐00: Model Observer Design and Its Validation for Task‐Based Evaluation of Digital Breast Tomosynthesis
Authors: Glick Stephen
Published: July 2016

Digital breast tomosynthesis (DBT), a limited‐angle tomographic technique by its nature has multiple optimal system configurations, which can lead to many potential changes to the existing and new DBT systems entering the US market. With the availability of computational tools such as for modeling imaging physics, it is becoming increasingly important to conduct virtual trials for a rigorous, preclinical and task‐based assessment of DBT. For such virtual assessment to be successful, it is critical to: (1) develop model‐observer approaches that can account for patient data statistics stemming from realistic or real breast backgrounds as well as lesion characteristics, thereby performing given tasks effectively and (2) validate the model‐observer approaches and their performance trends/levels with physical measurements from a prototype or real DBT system and a physical phantom ensemble. It is also important to understand trade‐offs between patient (phantom) sample/effect size and observer performance reliability for gaining knowledge on how to choose appropriate model observers for the given tasks. In this session, a variety of model‐observer approaches associated with currently available breast phantoms (either physical or virtual) and their sample size will be discussed. The presenters in this session will also discuss the limitations of each model observer approach to provide an understanding of the circumstances where each of these approaches can be more suitable than the others. The session is organized as follows: First, the development of virtual and physical phantoms that mimic breast anatomy will be presented. This will be followed by two presentations on model observers for DBT, one on the designing of model observers for signal‐known‐exactly (SKE) tasks and another on the development of visual search based model observers with the intent of identifying useful image features. Finally, this will be followed by practical examples where such model observers are applied to digital breast tomosynthesis.
TU‐AB‐209‐04: Practical Examples of Model Observer Applications in Digital Breast Tomosynthesis
Authors: Bosmans H.
Published: July 2016

Digital breast tomosynthesis (DBT), a limited‐angle tomographic technique by its nature has multiple optimal system configurations, which can lead to many potential changes to the existing and new DBT systems entering the US market. With the availability of computational tools such as for modeling imaging physics, it is becoming increasingly important to conduct virtual trials for a rigorous, preclinical and task‐based assessment of DBT. For such virtual assessment to be successful, it is critical to: (1) develop model‐observer approaches that can account for patient data statistics stemming from realistic or real breast backgrounds as well as lesion characteristics, thereby performing given tasks effectively and (2) validate the model‐observer approaches and their performance trends/levels with physical measurements from a prototype or real DBT system and a physical phantom ensemble. It is also important to understand trade‐offs between patient (phantom) sample/effect size and observer performance reliability for gaining knowledge on how to choose appropriate model observers for the given tasks. In this session, a variety of model‐observer approaches associated with currently available breast phantoms (either physical or virtual) and their sample size will be discussed. The presenters in this session will also discuss the limitations of each model observer approach to provide an understanding of the circumstances where each of these approaches can be more suitable than the others. The session is organized as follows: First, the development of virtual and physical phantoms that mimic breast anatomy will be presented. This will be followed by two presentations on model observers for DBT, one on the designing of model observers for signal‐known‐exactly (SKE) tasks and another on the development of visual search based model observers with the intent of identifying useful image features. Finally, this will be followed by practical examples where such model observers are applied to digital breast tomosynthesis.
TU‐B‐BRB‐03: Panel Member
Authors: Hadley S.
Published: July 2016

In this interactive session, liver SBRT patient cases will be presented to highlight real‐world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss approaches to challenges specific to liver SBRT including motion management, target delineation and imaging strategies, online treatment alignment, and appropriate prescription regimens and OAR dose limits. Audience participation will be encouraged.

Learning Objectives:

This panel session is designed to provide case demonstration and review for liver SBRT in terms of

clinical appropriateness in patient selection

strategies for motion management in simulation

treatment planning approaches with image fusion/co‐registration

image guidance in treatment delivery
TU‐A‐207B‐01: Imaging Genomics Associations and Biological Correlates of Radiomics
Authors: Zhu Y.
Published: July 2016

With the growth of quantitative imaging and quantitative image analysis, image‐based biomarkers (i.e. image‐based phenotypes) are becoming potential descriptors in personalized medicine as well as in cancer discovery research. Genomic study measures molecular cancer status and provides abundant information about cancer development mechanism. There is a need to understand the relationship between the image‐based cancer phenotypes (from radiomics) and the underlying molecular and genomic system. Imaging scientists and genomic scientists need to be able to speak the same language in this common era of Big Data. The objective of this session is to learn the basics and mathematics of phenotype‐genomics correlation and association studies, in particular radiomic phenotype‐genomic studies. We will take genomic data from The Cancer Genome Atlas (TCGA) and imaging data from The Cancer Imaging Archive (TCIA) as an example to show how to organize multi‐platform genomic data and integrate with quantitative tumor image phenotypes to perform association studies. We will show the software and procedure of discovering statistically significant associations between various imaging phenotypes (such as those characterizing tumor size, shape, margin, enhancement texture, and blood flow kinetics) and genomic features involved in multiple molecular regulation layers (including pathway gene expressions, pathway copy number variations, gene somatic mutations, miRNA expressions, and protein expressions). These findings form a basis for future studies using non‐invasive imaging techniques for accurate cancer diagnosis and prognosis and for discovering the genetic mechanisms leading to specific tumor phenotypes for the development of personalized cancer treatment.
TU‐B‐201‐02: Accounting for KV Imaging Dose
Authors: Alaei P.
Published: July 2016

Radiotherapy is in the era of image guided radiation therapy (IGRT) in which imaging procedures are routinely performed for patient positioning, and target localization. The additional imaging dose delivered may increase risk to the patient and therefore needs to be managed. This lecture provides an overview of the AAPM TG‐180 which is charged with: providing an overview on imaging dose including megavoltage electronic portal imaging (MV EPI), kilovoltage digital radiography (kV DR), Tomotherapy MV‐CT, megavoltage cone‐beam CT (MV‐CBCT) and kilovoltage cone‐beam CT (kV‐CBCT) as well as providing general guidelines for commissioning and managing imaging dose calculations. The dose to radiotherapy (RT) patients resulting from different image guidance procedures is reviewed and recommendations for managing the imaging dose are provided. Different techniques for reducing the image guidance dose are summarized. A recommended threshold beyond which imaging dose should be considered in the treatment planning process is discussed. This lecture also discusses kilovoltage imaging dose determination by calculation and estimation, and inclusion in treatment planning as well as accounting for MV imaging dose and the future of MV imaging.

Learning Objectives:

Learn the different image guidance modalities, typical organ doses resulting from different image procedures, and techniques to reduce the imaging dose;

Understand the imaging dose threshold and rationale for accounting for the imaging dose;

Learn how to account for kV imaging dose

Learn how to account for MV imaging dose and understand the future of MV imaging
TU‐B‐BRB‐00: PANEL DISCUSSION: SBRT/SRS Case Studies ‐ Liver
Authors: Brade Anthony , Evans Joshua
Published: July 2016

In this interactive session, liver SBRT patient cases will be presented to highlight real‐world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss approaches to challenges specific to liver SBRT including motion management, target delineation and imaging strategies, online treatment alignment, and appropriate prescription regimens and OAR dose limits. Audience participation will be encouraged.

Learning Objectives:

This panel session is designed to provide case demonstration and review for liver SBRT in terms of

clinical appropriateness in patient selection

strategies for motion management in simulation

treatment planning approaches with image fusion/co‐registration

image guidance in treatment delivery
TU‐B‐BRB‐02: Panel Member
Authors: Craig T.
Published: July 2016

In this interactive session, liver SBRT patient cases will be presented to highlight real‐world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss approaches to challenges specific to liver SBRT including motion management, target delineation and imaging strategies, online treatment alignment, and appropriate prescription regimens and OAR dose limits. Audience participation will be encouraged.

Learning Objectives:

This panel session is designed to provide case demonstration and review for liver SBRT in terms of

clinical appropriateness in patient selection

strategies for motion management in simulation

treatment planning approaches with image fusion/co‐registration

image guidance in treatment delivery
TU‐B‐206‐00: Do the Right Thing
Authors: Limmer Jeffrey
Published: July 2016

Purpose:

To reacquaint the participant with foundational aspects of educational, healthcare and research ethics as they relate to the Medical Physicist day to day role.

Methods:

Presenting recognized best practice guidelines and tenants applied to hypothetical scenarios and medical physics related occupations.

Results:

The application of recognized standards of ethical behavior result in beneficial outcomes for all involved

Conclusion:

Ethics is multi‐faceted in its manifestation application; most facets are applicable to any avenue a medical physicist may pursue in their career.

In its pure sense, ethics is the branch of philosophy that concerns itself with notions of right and wrong, particularly as applied to human behavior. Questions of ethics generally are different from and more challenging than questions of adherence to social norms, religious teachings or civil law. On a more pragmatic level, most professions have an established set of ethical standards to which those who practice the profession are expected to adhere, and a formal structure for sanctioning those practitioners who do not. Such is the case with Medical Physics and the AAPM's Code of Ethics.

This symposium will provide a brief refresher as to the philosophical grounding that informs the ethical practice of Medical Physics.

The study of ethics in general, and more specifically medical professional ethics, has a rich history. A framework for discussion of ethical questions, including common vocabulary and guiding concepts will be presented with an emphasis on tools that can be personalized and employed for guiding one's own practice. The connections will be explored between this conceptual framework and the form and substance of the AAPM's Code of Ethics, which is currently under review and revision. Finally there will be some discussion of the nature of struggles that have been observed over time as our membership of scientists and engineers attempt to find clarity in a realm of philosophy that is only very rarely amenable to logical analysis.

The attendee will be exposed to:

The definition of ethics including comparisons to similar concepts such as law and morals.

The concepts of ethical expectations of behavior and its origins

Examples and choice analysis in the areas of research, education, and the clinic

Practical application of methods to help avoid being placed in the situation where their ethical behavior is questioned as a medical physicist

Attendees should be able to:

Understand the scope of the philosophical domain of ethics, and be familiar with core concepts and vocabulary.

Recognize the broader considerations of ethical professional practice as they are captured in the AAPM Code of Ethics.

Appreciate the non‐linear, non‐deterministic, context‐sensitive nature of ethical considerations, and be able to more deeply appreciate the structural importance of compassion and empathy in human interaction.
TU‐B‐206‐02: On the Algorithmic Approach to Ethical Conduct
Authors: Sherouse G.
Published: July 2016

Purpose:

To reacquaint the participant with foundational aspects of educational, healthcare and research ethics as they relate to the Medical Physicist day to day role.

Methods:

Presenting recognized best practice guidelines and tenants applied to hypothetical scenarios and medical physics related occupations.

Results:

The application of recognized standards of ethical behavior result in beneficial outcomes for all involved

Conclusion:

Ethics is multi‐faceted in its manifestation application; most facets are applicable to any avenue a medical physicist may pursue in their career.

In its pure sense, ethics is the branch of philosophy that concerns itself with notions of right and wrong, particularly as applied to human behavior. Questions of ethics generally are different from and more challenging than questions of adherence to social norms, religious teachings or civil law. On a more pragmatic level, most professions have an established set of ethical standards to which those who practice the profession are expected to adhere, and a formal structure for sanctioning those practitioners who do not. Such is the case with Medical Physics and the AAPM's Code of Ethics.

This symposium will provide a brief refresher as to the philosophical grounding that informs the ethical practice of Medical Physics.

The study of ethics in general, and more specifically medical professional ethics, has a rich history. A framework for discussion of ethical questions, including common vocabulary and guiding concepts will be presented with an emphasis on tools that can be personalized and employed for guiding one's own practice. The connections will be explored between this conceptual framework and the form and substance of the AAPM's Code of Ethics, which is currently under review and revision. Finally there will be some discussion of the nature of struggles that have been observed over time as our membership of scientists and engineers attempt to find clarity in a realm of philosophy that is only very rarely amenable to logical analysis.

The attendee will be exposed to:

The definition of ethics including comparisons to similar concepts such as law and morals.

The concepts of ethical expectations of behavior and its origins

Examples and choice analysis in the areas of research, education, and the clinic

Practical application of methods to help avoid being placed in the situation where their ethical behavior is questioned as a medical physicist

Attendees should be able to:

Understand the scope of the philosophical domain of ethics, and be familiar with core concepts and vocabulary.

Recognize the broader considerations of ethical professional practice as they are captured in the AAPM Code of Ethics.

Appreciate the non‐linear, non‐deterministic, context‐sensitive nature of ethical considerations, and be able to more deeply appreciate the structural importance of compassion and empathy in human interaction.
TU‐D‐201‐02: Medical Physics Practices for Plan and Chart Review: Results of AAPM Task Group 275 Survey
Authors: Fong de los Santos L , Dong L , Greener A , Johnson J , Johnson P , Kim G , Mechalakos J , Napolitano B , Parker S , Schofield D , Wells M , Yorke E , Ford E
Published: July 2016

Purpose:

AAPM Task Group (TG) 275 is charged with developing riskbased guidelines for plan and chart review clinical processes. As part of this work an AAPM‐wide survey was conducted to gauge current practices.

Methods:

The survey consisted of 103 multiple‐choice questions covering the following review processes for external beam including protons: 1) Initial Plan Check, 2) On‐Treatment and 3) End‐of‐Treatment Chart Check. The survey was designed and validated by TG members with the goal of providing an efficient and easy response process. The survey, developed and deployed with the support of AAPM headquarters, was released to all AAPM members who have self‐reported as working in the radiation oncology field and it was kept open for 7 weeks.

Results:

There are an estimated 4700 eligible participants. At the time of writing, 962 completed surveys have been collected with an average completion time of 24 minutes. Participants are mainly from community hospitals (40%), academicaffiliated hospitals (31%) and free‐standing clinics (18%). Among many other metrics covered on the survey, results so far indicate that manual review is an important component on the plan and chart review process (>90%) and that written procedures and checklists are widely used (>60%). However, the details of what is reviewed or checked are fairly heterogeneous among the sampled medical physics community.

Conclusion:

The data gathered from the survey gauging current practices will be used by TG 275 to develop benchmarks and recommendations for the type and extent of checks to perform effective physics plan and chart review processes.
TU‐D‐201‐08: Experience Complying with The Joint Commission Element of Performance On Radiation Dose Index Monitoring
Authors: Supanich MP
Published: July 2016

Purpose:

A new Joint Commission element of performance effective July 2015 requires incidents where the radiation dose index exceeds a defined level be reviewed, analyzed and compared to external benchmarks. This work offers a comprehensive review of the CT exams in which the notification level was exceeded and the reason at one academic medical center. This review may help other institutions set reference levels at clinically relevant values.

Methods:

Radiation Dose Structured Reports from each of the 5 diagnostic CT scanners at our institution are automatically sent to our radiation dose index monitoring software platform, Radimetrics from Bayer Healthcare. Global notification levels for CTDIvol and DLP were configured in Radimetrics for head, chest and abdomen studies for 0–2 year old, 2–13 year old and adult age categories. Global CTDIvol notification levels were set lower than the AAPM recommended values. Additional notification levels were configured for specific protocols that do not use AEC or have better or limited image quality requirements. Notifications of exams exceeding the global or protocol specific notification levels were reviewed on an ongoing basis by a Qualified Medical Physicist and the reason(s) for the acquisition or exam exceeding the level recorded.

Results:

Out of 80 notifications for acquisitions or exams exceeding notification levels over an 8 month period, 72 occurred due to large patients or due to implants or external hardware in the scan range. Four instances of the incorrect protocol being selected were recorded and 4 instances of incorrect manual technique application were observed.

Conclusion:

Properly configured notification levels, even below those recommended by AAPM, produce few dose notifications on modern scanners using AEC and/or iterative reconstruction. Using SSDE instead of CTDI for notifications may provide more clinically relevant data on exams well above or below the clinical norm for dose and image quality.

Mark P. Supanich: Global Informatics Advisory Board Member: Bayer HealthCare
TU‐D‐BRC‐00: The EPID Strikes Back
Authors: Sawant Amit
Published: July 2016

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

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

Learning Objectives – In this symposium, the attendees will learn

Novel applications using currently available EPIDs

Use of EPIDs to perform in vivo dosimetry

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

J. Rottmann, Varian Medical SystemsP. Greer, Research Grant Funding from Radiation Oncology Institute (Grant ROI2013‐912), 2013–2014
TU‐D‐207B‐02: Delta‐Radiomics: The Prognostic Value of Therapy‐Induced Changes in Radiomics Features for Stage III Non‐Small Cell Lung Cancer Patients
Authors: Fave X , Zhang L , Yang J , Mackin D , Stingo F , Followill D , Balter P , Jones A , Gomez D , Court L
Published: July 2016

Purpose:

To determine how radiomics features change during radiation therapy and whether those changes (delta‐radiomics features) can improve prognostic models built with clinical factors.

Methods:

62 radiomics features, including histogram, co‐occurrence, run‐length, gray‐tone difference, and shape features, were calculated from pretreatment and weekly intra‐treatment CTs for 107 stage III NSCLC patients (5–9 images per patient). Image preprocessing for each feature was determined using the set of pretreatment images: bit‐depth resample and/or a smoothing filter were tested for their impact on volume‐correlation and significance of each feature in univariate cox regression models to maximize their information content. Next, the optimized features were calculated from the intratreatment images and tested in linear mixed‐effects models to determine which features changed significantly with dose‐fraction. The slopes in these significant features were defined as delta‐radiomics features. To test their prognostic potential multivariate cox regression models were fitted, first using only clinical features and then clinical+delta‐radiomics features for overall‐survival, local‐recurrence, and distant‐metastases. Leave‐one‐out cross validation was used for model‐fitting and patient predictions. Concordance indices(c‐index) and p‐values for the log‐rank test with patients stratified at the median were calculated.

Results:

Approximately one‐half of the 62 optimized features required no preprocessing, one‐fourth required smoothing, and one‐fourth required smoothing and resampling. From these, 54 changed significantly during treatment. For overall‐survival, the c‐index improved from 0.52 for clinical factors alone to 0.62 for clinical+delta‐radiomics features. For distant‐metastases, the c‐index improved from 0.53 to 0.58, while for local‐recurrence it did not improve. Patient stratification significantly improved (p‐value<0.05) for overallsurvival and distant‐metastases when delta‐radiomics features were included. The delta‐radiomics versions of autocorrelation, kurtosis, and compactness were selected most frequently in leave‐one‐out iterations.

Conclusion:

Weekly changes in radiomics features can potentially be used to evaluate treatment response and predict patient outcomes. High‐risk patients could be recommended for dose escalation or consolidation chemotherapy.

This project was funded in part by grants from the National Cancer Institute (NCI) and the Cancer Prevention Research Institute of Texas (CPRIT).
TU‐D‐207B‐04: Identifying High‐Risk Tumor Volume Based On Multi‐Region and Integrated Analysis of Multi‐Parametric MR Images for Prognostication of Glioblastoma
Authors: Ren X , Cui Y , Gao H , Li R
Published: July 2016

Purpose:

To identify high‐risk tumor volume for predicting survival in patients with glioblastoma on the basis of multi‐region and integrated analysis of multi‐parametric MR images.

Methods:

In this retrospectively study, 34 patients with glioblastoma from the Cancer Imaging Archive (TCIA) were analyzed. The patients were included if all of the pre‐operative 1) T1‐weighted contrast‐enhanced (T1c), 2) T2‐weighted fluid‐attenuation inversion recovery (FLAIR), and 3) diffusion‐weighted (DW) MR images were available. The apparent diffusion coefficient (ADC) map was calculated from the DW images. Both the FLAIR and ADC images were co‐registered onto the T1c image by rigid transformation. For each patient, gross tumor volume (GTV) was first semi‐automatically delineated with a cell automation and level‐set evolution algorithm. To fully capture the intrinsic intra‐tumor heterogeneity of glioblastoma reflected on multiparametric MR images, we further segmented the delineated tumor into several spatially distinct and phenotypically consistent subregions using k‐means clustering, with T1c, FLAIR, and ADC voxel intensities as input features. The optimal number of clusters was determined based on the Calinski‐Harabasz statistic. Finally, tumor volumes associated with potentially high‐risk subregions were evaluated in terms of overall survival (OS) prediction.

Results:

Three tumor subregions were identified within each glioblastoma. The tumor volume associated with the subregion of the lowest mean ADC values was prognostic of OS, with a concordance index (CI) of 0.648 (log‐rank P=0.005, hazard ratio=3.82) and outperforming GTV (CI=0.627, log‐rank P=0.019, hazard ratio=3.04). Less or similar prognostic performances were achieved for tumor volumes associated with subregions of the highest mean T1c intensities (CI=0.607, log‐rank P=0.035, hazard ratio=2.57) and the highest mean FLAIR intensities (CI=0.613, log‐rank P=0.014, hazard ratio=3.08).

Conclusion:

Multi‐region, integrated analysis of multi‐parametric MRI identified high‐risk tumor volume in glioblastoma. Integration of functional imaging with conventional MR sequences can potentially improve prediction of survival.
TU‐D‐207B‐05: Intra‐Tumor Partitioning and Texture Analysis of DCE‐MRI Identifies Relevant Tumor Subregions to Predict Early Pathological Response of Breast Cancer to Neoadjuvant Chemotherapy
Authors: Wu J , Gong G , Cui Y , Li R
Published: July 2016

Purpose:

To predict early pathological response of breast cancer to neoadjuvant chemotherapy (NAC) based on quantitative, multi‐region analysis of dynamic contrast enhancement magnetic resonance imaging (DCE‐MRI).

Methods:

In this institution review board‐approved study, 35 patients diagnosed with stage II/III breast cancer were retrospectively investigated using DCE‐MR images acquired before and after the first cycle of NAC. First, principal component analysis (PCA) was used to reduce the dimensionality of the DCE‐MRI data with a high‐temporal resolution. We then partitioned the whole tumor into multiple subregions using k‐means clustering based on the PCA‐defined eigenmaps. Within each tumor subregion, we extracted four quantitative Haralick texture features based on the gray‐level co‐occurrence matrix (GLCM). The change in texture features in each tumor subregion between pre‐ and during‐NAC was used to predict pathological complete response after NAC.

Results:

Three tumor subregions were identified through clustering, each with distinct enhancement characteristics. In univariate analysis, all imaging predictors except one extracted from the tumor subregion associated with fast wash‐out were statistically significant (p< 0.05) after correcting for multiple testing, with area under the ROC curve or AUCs between 0.75 and 0.80. In multivariate analysis, the proposed imaging predictors achieved an AUC of 0.79 (p = 0.002) in leave‐one‐out cross validation. This improved upon conventional imaging predictors such as tumor volume (AUC=0.53) and texture features based on whole‐tumor analysis (AUC=0.65).

Conclusion:

The heterogeneity of the tumor subregion associated with fast wash‐out on DCE‐MRI predicted early pathological response to neoadjuvant chemotherapy in breast cancer.
TU‐D‐207B‐07: Radiomic Response Assessment for Recurrent Glioblastoma Treated with Bevacizumab in the BRAIN Trial
Authors: Grossmann P , Narayan V , Huang R , Aerts H
Published: July 2016

Purpose:

To develop radiomic biomarkers for non‐invasive response assessment of Bevacizumab (Avastin; Genentech) treatment in recurrent glioblastoma multiforme (GBM).

Methods:

We analyzed prospectively acquired data from the BRAIN trial. For 167 patients, we extracted 71 radiomic features each from normalized post‐contrast T1‐weighted and fluid attenuation inversion recovery (FLAIR) sequences at baseline (pretreatment), and at follow‐ups of six and twelve weeks (post‐treatment), respectively, where available. For every imaging modality and time point, we selected 10 comprehensive features using an unsupervised feature selection approach that did not take clinical outcomes into account to limit overfitting. We investigated these features in terms of their prognostic value for overall survival (OS), progression‐free survival (PFS), as well as early and late progressors.

Results:

T1 and FLAIR features showed only low correlation at baseline (mean positive and negative Pearson correlation of ‐ 0.13 and 0.3) indicating complementary effects of imaging modalities at the radiomic level. We identified a textural‐heterogeneity feature (large area emphasis) that had higher prognostic value of OS at baseline as compared to conventional tumor volume (C‐index 0.71 vs 0.52, p = 0.006). Highest prognostic value was observed for the delta difference between baseline and six week follow‐up values for short‐run lengths of image intensities (Cindex 0.86, p = 2×10−8). Radiomic features generally showed similar or lower performances for PFS. Comparing radiomic feature values of early and late progressors directly showed significant differences in tumor surface and textural features after correcting for multiple‐testing (Wilcoxon rank sum test, p < 0.05).

Conclusion:

For the first time, our study allows the definition of radiomic response phenotypes of Bevacizumab treatment in recurrent GBM by leveraging high‐quality prospective trial data. Importantly, our data suggests the increased benefit of measuring radiomic patient profiles longitudinally after treatment has been initiated to monitor progression and resistance for immediate intervention and treatment adaptation.
TU‐FG‐204‐00: Compliance with the AAPM CT Clinical Practice and Joint Commission Guidelines
Authors: Szczykutowicz Timothy
Published: July 2016

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

Learning Objectives:

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

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

T. Szczykutowicz, TPS provides CT protocols to GE Healthcare under a license agreement. TPS receives grant support from GE Healthcare.
TU‐FG‐204‐04: An Overview of the CT Protocol Optimization Team at MD Anderson Cancer Center
Authors: Cody D.
Published: July 2016

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

Learning Objectives:

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

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

T. Szczykutowicz, TPS provides CT protocols to GE Healthcare under a license agreement. TPS receives grant support from GE Healthcare.
TU‐FG‐204‐05: Diagnostic Imaging: Surveyor Education, Survey Experience, and Trends
Authors: Browne A.
Published: July 2016

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

Learning Objectives:

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

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

T. Szczykutowicz, TPS provides CT protocols to GE Healthcare under a license agreement. TPS receives grant support from GE Healthcare.
TU‐FG‐207B‐00: Federal Funding Opportunities and Grantsmanship
Authors: Farahani Keyvan
Published: July 2016

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

Learning Objectives:

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

To learn about tactics important for crafting convincing research proposals

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

B. Whelan, this work was commissioned and funded by the AAPM
TU‐FG‐207B‐02: NIBIB Funding Opportunities
Authors: Krosnick S.
Published: July 2016

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

Learning Objectives:

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

To learn about tactics important for crafting convincing research proposals

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

B. Whelan, this work was commissioned and funded by the AAPM
TU‐FG‐207B‐03: NCI Small Business Funding Opportunities
Authors: Narayanan D.
Published: July 2016

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

Learning Objectives:

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

To learn about tactics important for crafting convincing research proposals

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

B. Whelan, this work was commissioned and funded by the AAPM
TU‐E‐TOUR‐T‐01: Microdosimeters for Therapy
Authors: Das I.
Published: July 2016

Tour Leader: Indra Das, NYU Langone Medical Center, New York, NY

Tour Guides:

Hsui Ai, Indiana University School of Medicine, Indianapolis, IN

Aaron Andersen, Indiana University School of Medicine, Indianapolis, IN

Olga Volotoskova, NYU Langone Medical Center, New York, NY

Participating Vendors:

IBA

PTW – New York

RTI Electronics, Inc.

Standard Imaging, Inc.

Sun Nuclear Corporation

Small fields are increasing used in specialized radiation treatments such as Gammaknife, Cyberknife, Tomotherapy, IMRT, VMAT, SRS and SBRT. Due to small field size electron transport creates lateral electronic disequilibrium and thus dosimetry could be very difficult. Microdetectors are used for small field dosimetry which will be discussed in preface of this tour as below:

Understanding small field e.g. meaning and definition of small field

IAEA definition and approach

Characteristics of microdetectors in terms of perturbation, recombination, correction

Suitability of microdetectors in small field dosimetry
TU‐H‐204‐03: NCRP PAC 4 (Radiation Protection in Medicine)
Authors: Miller D.
Published: July 2016

Since 1928, the International Commission on Radiological Protection (ICRP) has developed, maintained, and elaborated the International System of Radiological Protection used world‐wide as the common basis for radiological protection standards, legislation, guidelines, programs, and practice. ICRP provides and periodically revises radiation and tissue weighing factors, provides and updates recommended dose limits for occupational and public exposures, recommends dose levels for termination of pregnancy, and estimates threshold doses for tissue reactions (deterministic effects). ICRP developed the dose quantity “effective dose”.

NCRP Council Committee 1 (CC‐1) is charged with developing recommendations for revising radiation protection guidance for the United States. Topics to be discussed include a summary of current ICRP guidance, NCRP CC‐1 directions, NRC regulatory changes on the horizon, and potential implications of radiation protection guidance changes on the practice of medicine. The opinions of AAPM members on potential changes are welcomed.

NCRP Program Area Committee (PAC) 4 has oversight of activities in radiation protection in medicine, including protection of patients and training of health care workers. Documents have been published recently on diagnostic reference levels and achievable doses, health effects of preconception and prenatal radiation exposure, and administrative policies for quality assurance and peer review of tissue reactions associated with fluoroscopically guided interventions. Additional documents are in preparation.

Learning Objectives:

To understand the international system of radiation protection and learn about the work of the International Commission on Radiological Protection (ICRP) in relation to activities of medical physicists

To understand the ongoing work of NCRP in developing new guidance for radiation protection in the U.S.

To understand the ongoing work of NCRP in developing new recommendations for radiation protection in medicine.

To learn about other national organizations in US whose work plays a useful role in the activities of medical physicists.

M. Rehani, Work done as part of being member of ICRP. ICRP is an independent charity.
TU‐H‐201‐01: Introduction
Authors: Curran B.
Published: July 2016

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

After the symposium a social hour ensues with opportunities to interact with key AAPM members. The New Member Symposium is a (free) ticket option when you register online for the Annual Meeting. And don't forget registrants receive one (free) ticket for a beverage of your choice during the social afterwards.
TU‐H‐BRC‐02: Biological Dose Escalation for Liver SBRT Through Spatiotemporal Fractionation
Authors: Unkelbach J , Perko Z , Wolfgang J , Hong T
Published: July 2016

Purpose:

Stereotactic body radiotherapy (SBRT) has become an established treatment option for liver cancer. For patients with large tumors, the prescription dose is often limited by constraints on the mean liver dose, leading to tumor recurrence. In this work, we demonstrate that spatiotemporal fractionation schemes, ie delivering distinct dose distributions in different fractions, may allow for a 10% increase in biologically effective dose (BED) in the tumor compared to current practice where each fraction delivers the same dose distribution.

Methods:

We consider rotation therapy delivered with x‐ray beams. Treatment plan optimization is performed using objective functions evaluated for the cumulative BED delivered at the end of treatment. This allows for simultaneously optimizing multiple distinct treatment plans for different fractions.

Results:

The treatment that optimally exploits fractionation effects is designed such that each fraction delivers a similar dose bath to the uninvolved liver while delivering high single fraction doses to complementary parts of the target volume. Thereby, partial hypofractionation in the tumor is achieved along with near uniform fractionation in the surrounding liver ‐ leading to an improvement in the therapeutic ratio. The benefit of such spatiotemporal fractionation schemes depends on tumor geometry and location as well as the number of fractions. For 5‐fraction treatments (allowing for 5 distinct dose distributions) an improvement in the order of 10% is observed.

Conclusion:

Delivering distinct dose distributions in different fractions, purely motivated by fractionation effects rather than geometric changes, may improve the therapeutic ratio. For treatment sites where the prescriptions dose is limited by mean dose constraints in the surrounding organ, such as liver cancer, this approach may facilitate biological dose escalation and improved cure rates.
TU‐H‐BRC‐03: Evaluation of Very High‐Energy Electron (VHEE) Beams in Comparison to VMAT and PBS Treatment Plans
Authors: Schueler E , Eriksson K , Hynning E , Loo B , Maxim P
Published: July 2016

Purpose:

The aim of this study was to evaluate the performance of very high‐energy electron (VHEE) beams in comparison to clinically delivered treatment plans generated with volumetric modulated arc therapy (VMAT) and proton pencil beam scanning (PBS) technology.

Methods:

Three clinical cases were selected (prostate, lung, and pediatric CNS). The VHEE plans were calculated in the Monte Carlo EGSnrc code and pencil beam doses were calculated using the DOSxyznrc MC code for 100 and 200 MeV beams. Treatment plans with VHEE, VMAT, and PBS were optimized in a research version of RayStation using an in house build script in order to minimize operator bias between the different techniques.

Results:

For the prostate cancer case, the PBS plan showed lower mean organ at risk (OAR) doses compared to the other modalities. An exception was the femoral heads, due to the lateral beam arrangements. The VMAT plan showed lower mean doses to the rectum and the bladder compared to the 100 MeV VHEE plan. The lung cancer case showed minor differences between the three modalities. However, the PBS plan showed a lower contralateral lung dose. The pediatric CNS case showed a better conformity and lower spinal cord dose for the 100 MeV VHEE plan. For all cases, the 200 MeV VHEE plans were found to be similar to or better than the 100 MeV VHEE plans.

Conclusion:

The present study showed that VHEE plans are similar or superior to VMAT plans with reduced mean OAR dose and increased target conformity for a variety of clinical cases. With increased VHEE energy, better conformity and even higher reductions in mean OAR doses can be achieved.

Funding: DoD, Award#:W81XWH‐13‐1‐0165, Weston Havens Foundation, Bio‐X (Stanford University), the Office of the Dean of the Medical School, the Office of the Provost (Stanford University), and the Swedish Childhood Cancer Foundation. BL and PM are founders of TibaRay,Inc. BL and PM have received research grants from Varian and RaySearch Laboratory.