bluuebunny/crossref_metadata_2025 huggingface dataset:
TU‐AB‐BRA‐07: Distortion‐Free 3D Diffusion MRI On An MRI‐Guided Radiotherapy System for Longitudinal Tumor Response Assessment
Authors: Gao Y , Yang Y , Rangwala N , Cao M , Low D , Hu P
Published: July 2016

Purpose:

To develop a reliable, 3D distortion‐free diffusion MRI technique for longitudinal tumor response assessment and MRI‐guided adaptive radiotherapy(RT).

Methods:

A diffusion prepared 3D turbo spin echo readout (DP‐TSE) sequence was developed and compared with the conventional diffusion‐weighted single‐shot echo‐planar‐imaging (DW‐ssEPI) sequence in a commercially available diffusion phantom, and one head‐and‐neck and one brain cancer patient on an MRI‐guided RT system (ViewRay). In phantom study, the geometric fidelity was quantified as the ratio between the left‐right (RL) and anterior‐posterior (AP) dimension. Ten slices were measured on DP‐TSE, DW‐ssEPI and standard TSE images where the later was used as the geometric reference. ADC accuracy was verified at both 0°C (reference ADC available) and room temperature with a range of diffusivity between 0.35 and 2.0*10−3mm2/s. The ADC reproducibility was assessed based on 8 room‐temperature measurements on 6 different days. In the pilot single‐slice in‐vivo study, CT images were used as the geometric reference, and ADC maps from both diffusion sequences were compared.

Results:

Distortion and susceptive‐related artifact were severe in DW‐ssEPI, with significantly lower RL/AP ratio (0.9579±0.0163) than DP‐TSE (0.9990±0.0031) and TSE (0.9995±0.0031). ADCs from the two diffusion sequences both matched well with the vendor‐provided values at 0°C; however DW‐ssEPI fails to provide accurate ADC for high diffusivity vials at room temperature due to high noise level (10 times higher than DP‐TSE). The DP‐TSE sequence had excellent ADC reproducibility with <4% ADC variation among 8 separate measurements. In patient study, DP‐TSE exhibited substantially improved geometric reliability. ROI analysis in ADC maps generated from DP‐TSE and DW‐ssEPI showed <5% difference where high b‐value images were excluded from the latter approach due to excessive noise level.

Conclusion:

A diffusion MRI sequence with excellent geometric fidelity, accurate and highly reproducible ADC measurements was proposed for longitudinal tumor response assessment using an MRI‐guided RT system.

Yu Gao acknowledges research support from ViewRay.
TU‐AB‐BRA‐08: Slice by Slice Approach to Quantifying Inter‐Fractional Organ Motion
Authors: Mazur T , Cardenas M , Li H , Mutic S , Bradley J , Tsien C , Green O
Published: July 2016

Purpose:

To demonstrate the feasibility of a rapid computational algorithm for generating esophageal margin expansions.

Methods:

Inter‐fraction MRI allows visualization of relative variations of the esophagus and other critical structures when compared to planning CT. We have developed a rapid computational method for quantifying this motion. CT simulation and on‐treatment MR data sets of seven patients were obtained using a 0.3 T MR‐guided RT system. Rigid registration guided by bony anatomy from the cricoid to the gastro‐esophageal junction was used for transferring CT contours to MR volumes. CT‐ and MR‐based contours were re‐sampled to form boundaries – BCT and BMR respectively – that densely sample the image grid. Centroids CCT and CMR were calculated slice‐by‐slice from BCT and BMR respectively. For each CT boundary point BCT(i) within an area enclosed by the MR boundary points, the intersection BMR(j) was calculated between the MR boundary and a line defined by BCT(i) and CCT. The length of the vector defined by BCT(i) and BMR(j) provides a margin expansion within a given slice for that vector orientation. This procedure is repeated for every slice to characterize margin expansions along the esophagus.

Results:

Expansions were determined for in‐plane quadrants along the length of the esophagus. With the analysis relying on simple geometry, the non‐negligible time constraint in the procedure is manual contouring. Given the soft tissue contrast on MR volumes, systematic margin uncertainties are ultimately determined by in‐plane spatial resolution (1.5×1.5 mm2 in most cases).

Conclusion:

We demonstrate a rapid method for assessing inter‐fractional variation for the sake of suggesting thorough treatment margins (applied to the esophagus). Ongoing work aims to assess intra‐fractional esophageal motion.
TU‐AB‐BRA‐09: A Novel Method of Generating Ultrafast Volumetric Cine MRI (VC‐MRI) Using Prior 4D‐MRI and On‐Board Phase‐Skipped Encoding Acquisition for Radiotherapy Target Localization
Authors: Wang C , Yin F , Harris W , Cai J , Chang Z , Ren L
Published: July 2016

Purpose:

To develop a technique generating ultrafast on‐board VC‐MRI using prior 4D‐MRI and on‐board phase‐skipped encoding k‐space acquisition for real‐time 3D target tracking of liver and lung radiotherapy.

Methods:

The end‐of‐expiration (EOE) volume in 4D‐MRI acquired during the simulation was selected as the prior volume. 3 major respiratory deformation patterns were extracted through the principal component analysis of the deformation field maps (DFMs) generated between EOE and all other phases. The on‐board VC‐MRI at each instant was considered as a deformation of the prior volume, and the deformation was modeled as a linear combination of the extracted 3 major deformation patterns. To solve the weighting coefficients of the 3 major patterns, a 2D slice was extracted from VC‐MRI volume to match with the 2D on‐board sampling data, which was generated by 8‐fold phase skipped‐encoding k‐space acquisition (i.e., sample 1 phase‐encoding line out of every 8 lines) to achieve an ultrafast 16–24 volumes/s frame rate. The method was evaluated using XCAT digital phantom to simulate lung cancer patients. The 3D volume of end‐ofinhalation (EOI) phase at the treatment day was used as ground‐truth onboard VC‐MRI with simulated changes in 1) breathing amplitude and 2) breathing amplitude/phase change from the simulation day. A liver cancer patient case was evaluated for in‐vivo feasibility demonstration.

Results:

The comparison between ground truth and estimated on‐board VC‐MRI shows good agreements. In XCAT study with changed breathing amplitude, the volume‐percent‐difference(VPD) between ground‐truth and estimated tumor volumes at EOI was 6.28% and the Center‐of‐Mass‐Shift(COMS) was 0.82mm; with changed breathing amplitude and phase, the VPD was 8.50% and the COMS was 0.54mm. The study of liver patient case also demonstrated a promising in vivo feasibility of the proposed method

Conclusion:

Preliminary results suggest the feasibility to estimate ultrafast VC‐MRI for on‐board target localization with phase skipped‐encoding k‐space acquisition.

Research grant from NIH R01‐184173
TU‐A‐206‐00: Professional Liability Insurance ‐ What You Need to Know
Authors: Jordan David
Published: July 2016

Professional liability insurance is an important tool to manage risks to a medical physicist's assets that can result from errors or omissions in the course of professional practice. AAPM has partnered with Mercer Consumer to offer coverage tailored to the professional activities and specific risks encountered in medical physics practice. This program has specific eligibility criteria, benefit options, exclusions, and enrollment options for both self‐employed medical physicists and those who practice in an employment setting.

There are important nuances to the form of coverage chosen and the determination of the coverage period for individual policies. The need for and role of professional liability insurance varies for each individual physicist, and one of the most important factors is the physicist's employment or self‐employment status and involvement in consulting activities.

This session will provide an overview of the AAPM‐sponsored program (administered by Mercer) and the various options available to consulting and employed physicists. The fundamental concepts of professional liability insurance in general will be reviewed, and the roles of occurrence and claims‐made coverage forms within the AAPM program will be explained. Information drawn from claims data from the AAPM program will be used to illustrate the role of professional liability insurance benefits in realistic cases involving losses and liabilities due to errors and omissions in medical physics practice.

Learning Objectives:

Explain how professional liability insurance protects a medical physicist in the event of a lawsuit.

Understand the basic concepts of the professional liability insurance coverage forms: occurrence and claims‐made.

Explain AAPM's professional liability insurance program for the consulting and non‐consulting medical physicist.

Understand the recent claim/expense data from AAPM's professional liability insurance program.

Graham Fuller is an employee of Mercer Consumer.
TU‐A‐206‐02: Is Professional Liability Insurance Really Necessary
Authors: Orfali A.
Published: July 2016

Professional liability insurance is an important tool to manage risks to a medical physicist's assets that can result from errors or omissions in the course of professional practice. AAPM has partnered with Mercer Consumer to offer coverage tailored to the professional activities and specific risks encountered in medical physics practice. This program has specific eligibility criteria, benefit options, exclusions, and enrollment options for both self‐employed medical physicists and those who practice in an employment setting.

There are important nuances to the form of coverage chosen and the determination of the coverage period for individual policies. The need for and role of professional liability insurance varies for each individual physicist, and one of the most important factors is the physicist's employment or self‐employment status and involvement in consulting activities.

This session will provide an overview of the AAPM‐sponsored program (administered by Mercer) and the various options available to consulting and employed physicists. The fundamental concepts of professional liability insurance in general will be reviewed, and the roles of occurrence and claims‐made coverage forms within the AAPM program will be explained. Information drawn from claims data from the AAPM program will be used to illustrate the role of professional liability insurance benefits in realistic cases involving losses and liabilities due to errors and omissions in medical physics practice.

Learning Objectives:

Explain how professional liability insurance protects a medical physicist in the event of a lawsuit.

Understand the basic concepts of the professional liability insurance coverage forms: occurrence and claims‐made.

Explain AAPM's professional liability insurance program for the consulting and non‐consulting medical physicist.

Understand the recent claim/expense data from AAPM's professional liability insurance program.

Graham Fuller is an employee of Mercer Consumer.
TU‐AB‐209‐01: Virtual and Physical Breast Phantoms That Mimic Patients
Authors: Lo J.
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‐A‐207B‐00: Imaging Genomics Associations and Biological Correlates of Radiomics
Authors: Zhu Yitan
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‐201‐00: TG180: Imaging Dose During RT
Authors: Ding George
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‐201‐01: An Overview of TG‐180
Authors: Ding G.
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‐01: Panel Member
Authors: Brade A.
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‐206‐01: Navigating the Black, White, and Gray
Authors: Limmer J.
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‐207B‐00: Challenges in Radiomics and Big Data
Authors: Drukker Karen
Published: July 2016

The general learning objectives are to get a better understanding of

The pitfalls along the radiomics/radiogenomics (imaging genomics) pipeline

The crucial role of statistics in the design and evaluation of radiomics/radiogenomics phenotypes and systems

The special challenges associated with big data

Introduction

Basic statistical concepts

Association, correlation, and causality

Know when your numbers are significant

Reproducibility

Replication studies

The extent of the problem

Curse of dimensionality, overfitting, multiple hypothesis testing

Sample size, P‐value variability

“Big Data”

“Big data” vs. “medium data” vs. “small data”

Training and testing data sets

Harmonization

KD receives royalties from Hologic
TU‐B‐207B‐01: Challenges in Radiomics and Big Data
Authors: Drukker K.
Published: July 2016

The general learning objectives are to get a better understanding of

The pitfalls along the radiomics/radiogenomics (imaging genomics) pipeline

The crucial role of statistics in the design and evaluation of radiomics/radiogenomics phenotypes and systems

The special challenges associated with big data

Introduction

Basic statistical concepts

Association, correlation, and causality

Know when your numbers are significant

Reproducibility

Replication studies

The extent of the problem

Curse of dimensionality, overfitting, multiple hypothesis testing

Sample size, P‐value variability

“Big Data”

“Big data” vs. “medium data” vs. “small data”

Training and testing data sets

Harmonization

KD receives royalties from Hologic
TU‐C‐HORIZONS‐01: The Expanding Horizons Travel Grant Program: ePosters and Discussion
Authors: Siewerdsen J , Jeraj R
Published: July 2016

The Expanding Horizons travel grant program provides opportunity for students and trainees to broaden the scope of scientific meetings they attend and gain insight from research outside traditional domains of medical physics. Through participation in such conferences, early‐career researchers are introduced to new topics with relevance to medical physics research as a means to expand the scientific horizons of our discipline. This year, 21 Expanding Horizons travel grants were awarded, granting travel to 17 conferences, including: Radiomics, the World Molecular Imaging Society (WMIS), the 3D Printing Conference and Expo, the GPU Technology Conference, the SIAM Imaging Science Conference, the Human Brain Mapping Conference, the OSA Conference on Clinical and Translational Biophotonics, the Society for Neuroscience, the AACR Conference on Tumor Microenvironment, and the Conference on Knowledge Discovery and Data Mining. The Expanding Horizons electronic poster session gives a venue for AAPM conference attendees to meet and discuss with awardees, learn the hot topics and emerging research areas presented at these conferences, and understand the relevance to future medical physics research.
TU‐D‐BRC‐01: Novel Applications for Current EPID Technology
Authors: Rottmann J.
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‐BRC‐03: Future EPID Technology and Applications
Authors: Antonuk L.
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‐202‐01: Is ITV the Correct Motion Encompassing Strategy?
Authors: van Herk M.
Published: July 2016

Respiratory motion has long been recognized as an important factor affecting the precision of radiotherapy. After the introduction of the 4D CT to visualize the respiratory motion in 3D, the internal target volume (ITV) has been widely adopted as simple method to take the motion into account in treatment planning and delivery. The ITV is generated as the union of the CTVs as the patient goes through the respiratory cycle. Many issues have been identified with the ITV. In this session three alternatives for the ITV will be discussed: 1) An alternative motion‐inclusive approach with better imaging and smaller margins, called mid‐position CT. 2) The tracking approach and 3) The gating approach.

The following topics will be addressed by Marcel van Herk (“Is ITV the correct motion encompassing strategy”): Magnitude of respiratory motion, effect of motion on radiotherapy, motion encompassing strategies, and software solutions to assist in motion encompassing strategies. Then Paul Keall (“Make margins simple: Use real‐time target tracking”) will discuss tracking with: clinical drivers for tracking, current clinical status of tumor tracking, future tumor tracking technology, and margin margin challenges with and without tracking. Finally Daniel Low will discuss gating (“Gating is the best ITV killer”): why ITV in the first place, requirements for planning, requirements at the machine, benefits and costs.

The session will end with a discussion and live demo of motion simulation software to illustrate the issues and explain the relative benefit and appropriate uses for the three methods.

Learning Objectives:

Explain the 4D imaging and treatment planning process.

Summarize the various approaches to deal with respiratory motion during radiotherapy

Discuss the tradeoffs involved when choosing one of the three discussed approaches.

Explain in which situation each method is the best choice

Research is partly funded by Elekta Oncology Systems and the Dutch Cancer Foundation; M. van Herk, Part of the research was funded by Elekta Oncology Systems and the Dutch Cancer Foundation
TU‐D‐206‐02: Body Tomosynthesis Image Features and Artifacts
Authors: Flynn M.
Published: July 2016

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

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

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

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

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

Learning Objectives:

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

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

Learn to radiation dose associated with common protocols.

Understand how to best evaluate a newly purchased tomosynthesis system.

J. Sabol, Presenter is an employee of GE Healthcare.
TU‐D‐206‐04: Body TS Acceptance Testing and QC
Authors: Jones A.
Published: July 2016

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

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

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

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

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

Learning Objectives:

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

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

Learn to radiation dose associated with common protocols.

Understand how to best evaluate a newly purchased tomosynthesis system.

J. Sabol, Presenter is an employee of GE Healthcare.
TU‐D‐209‐03: Alignment of the Patient Graphic Model Using Fluoroscopic Images for Skin Dose Mapping
Authors: Oines A , Oines A , Kilian‐Meneghin J , Karthikeyan B , Rudin S , Bednarek D
Published: July 2016

Purpose:

The Dose Tracking System (DTS) was developed to provide realtime feedback of skin dose and dose rate during interventional fluoroscopic procedures. A color map on a 3D graphic of the patient represents the cumulative dose distribution on the skin. Automated image correlation algorithms are described which use the fluoroscopic procedure images to align and scale the patient graphic for more accurate dose mapping.

Methods:

Currently, the DTS employs manual patient graphic selection and alignment. To improve the accuracy of dose mapping and automate the software, various methods are explored to extract information about the beam location and patient morphology from the procedure images. To match patient anatomy with a reference projection image, preprocessing is first used, including edge enhancement, edge detection, and contour detection. Template matching algorithms from OpenCV are then employed to find the location of the beam. Once a match is found, the reference graphic is scaled and rotated to fit the patient, using image registration correlation functions in Matlab. The algorithm runs correlation functions for all points and maps all correlation confidences to a surface map. The highest point of correlation is used for alignment and scaling. The transformation data is saved for later model scaling.

Results:

Anatomic recognition is used to find matching features between model and image and image registration correlation provides for alignment and scaling at any rotation angle with less than onesecond runtime, and at noise levels in excess of 150% of those found in normal procedures.

Conclusion:

The algorithm provides the necessary scaling and alignment tools to improve the accuracy of dose distribution mapping on the patient graphic with the DTS.

Partial support from NIH Grant R01‐EB002873 and Toshiba Medical Systems Corp.
TU‐D‐207B‐06: Pathological Response Prediction by Radiomic Data From Primary and Lymph Nodes in NSCLC
Authors: Coroller T , Agrawal V , Narayan V , Lee S , Mak R , Aerts H
Published: July 2016

Purpose:

In advanced non‐small cell lung cancer (NSCLC) patient, metastasis can spread from the primary tumor to the lymph nodes and hence could have a distinct phenotype compared to unaffected nodes. In this study we investigated the complementary information of radiomics extracted from lymph nodes and the primary tumor in order to predict pathological response at time of surgery after chemoradiation in patients with stage II‐III NSCLC.

Methods:

86 NSCLC patients with primary tumor and involved lymph nodes (LN) were included in this study. Twenty radiomic features were selected based on stability and variance. Predictive power was evaluated using AUC and false discovery rate (FDR) corrected p‐values. Conventional imaging features (total tumor / LN volume and axial tumor diameter) and clinical characteristics were included for comparison. Classification power was investigated using random forest. Performances were assessed using cross validation (1000 iterations, 70% training / 30% validation).

Results:

Three radiomic features were predictive for pathologic (GRD) gross residual disease (AUC range 0.69–0.75, p<0.05) and two pathologic (pCR) complete response (AUC range 0.65–0.68, p<0.05). No conventional imaging features were predictive of either outcome (range AUC = 0.51 to 0.61, p>0.05). Patients with pCR were likely to have more homogeneous LN (large area emphasis, AUC=0.74, p<0.05) when in the other hand patients with GRD present rounder primary tumor shape (spherical disproportionality, AUC= 0.68 p<0.05). Cross validation AUC values shown that the combined radiomics‐clinical features set outperformed for each outcomes (median AUC = 0.68 and 0.74 respectively for pCR and GRD).

Conclusion:

We demonstrate that LN phenotypic information, ascertained from radiomic features, is complementary to imaging features obtained from the primary tumor. These features are strongly associated with response to chemoradiation as determined by pathologic response and provide greater predictive performance than clinical characteristics and conventional assessment of tumor burden by diameter or volume.

R.M. have consulting interest with Amgen.
TU‐D‐PinS Room/Hall E‐01: Siemens Digital Breast Tomosynthesis: Design of a Wide Angle System & Quality Control
Authors: Klinnert T.
Published: July 2016

This session along with the others on Digital Breast Tomosynthesis (DBT) offered at this years meeting as part of the Educational, Scientific and Partners in Solutions is intended to meet the FDA requirements for physicists to survey a DBT system. Specifically, this vendor offered session held as part of the Partners in Solutions is also meant to focus on those requirements. This session is being done along with the other two vendors of approved DBT systems in order to cover the machine specific features of those systems.

Learning Objectives:

Meet FDA requirement of introducing vendor specific features of this respective DBT system
TU‐FG‐207B‐05: Funding Opportunities at the National Science Foundation
Authors: Olbricht W.
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‐H‐204‐02: Work of NRC, States and of re‐evaluating dose limits by NCRP
Authors: Dauer L.
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‐201‐00: New Member Symposium
Authors: Keener Justin , Johnson Amirh
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‐201‐02: AAPM Overview
Authors: Miller R.
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‐07: Therapeutic Benefit in Spatially Fractionated Radiotherapy (GRID) Using Helical Tomotherapy
Authors: Narayanasamy G , Zhang X , Meigooni A , Liang X , Paudel N , Morrill S , Maraboyina S , Peacock L , Penagaricano J
Published: July 2016

Purpose:

The aim of this project is to study the therapeutic ratio (TR) for helical Tomotherapy (HT) based spatially fractionated radiotherapy (GRID). Estimation of TR was based on the linear‐quadratic cell survival model by comparing the normal cell survival in a HT GRID to that of a uniform dose delivery in an open‐field for the same tumor survival.

Methods:

HT GRID plan was generated using a patient specific virtual GRID block pattern of non‐divergent, cylinder shaped holes using MLCs. TR was defined as the ratio of normal tissue surviving fraction (SF) under HT GRID irradiation to an open field irradiation with an equivalent dose that result in the same tumor cell SF. The ratio was estimated from DVH data on ten patient plans with deep seated, bulky tumor approved by the treating radiation oncologist. Dependence of the TR values on radio‐sensitivity of the tumor cells and prescription dose were also analyzed.

Results:

The mean ± standard deviation (SD) of TR was 4.0±0.7 (range: 3.1 to 5.5) for the 10 patients with single fraction dose of 20 Gy and tumor cell SF of 0.5 at 2 Gy. In addition, mean±SD of TR = 1±0.1 and 18.0±5.1 were found for tumor with SF of 0.3 and 0.7, respectively. Reducing the prescription dose to 15 and 10 Gy lowered the TR to 2.0±0.2 and 1.2±0.04 for a tumor cell SF of 0.5 at 2 Gy. In this study, the SF of normal cells was assumed to be 0.5 at 2 Gy.

Conclusion:

HT GRID displayed a significant therapeutic advantage over uniform dose from an open field irradiation. TR increases with the radioresistance of the tumor cells and with prescription dose.