bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐AB‐202‐06: Quantitative Evaluation of Deformable Image Registration in MRI‐Guided Adaptive Radiation Therapy
Authors: Mooney K , Zhao T , Duan Y , Zhang M , Green O , Mutic S , Yang D 
Published: July 2016

Purpose:To assess the performance of the deformable image registration algorithm used for MRI‐guided adaptive radiation therapy using image feature analysis.Methods:MR images were collected from five patients treated on the MRIdian (ViewRay, Inc., Oakwood Village, OH), a three head Cobalt‐60 therapy machine with an 0.35 T MR system. The images were acquired immediately prior to treatment with a uniform 1.5 mm resolution. Treatment sites were as follows: head/neck, lung, breast, stomach, and bladder. Deformable image registration was performed using the ViewRay software between the first fraction MRI and the final fraction MRI, and the DICE similarity coefficient (DSC) for the skin contours was reported. The SIFT and Harris feature detection and matching algorithms identified point features in each image separately, then found matching features in the other image. The target registration error (TRE) was defined as the vector distance between matched features on the two image sets. Each deformation was evaluated based on comparison of average TRE and DSC.Results:Image feature analysis produced between 2000–9500 points for evaluation on the patient images. The average (± standard deviation) TRE for all patients was 3.3 mm (±3.1 mm), and the passing rate of TRE<3 mm was 60% on the images. The head/neck patient had the best average TRE (1.9 mm±2.3 mm) and the best passing rate (80%). The lung patient had the worst average TRE (4.8 mm±3.3 mm) and the worst passing rate (37.2%). DSC was not significantly correlated with either TRE (p=0.63) or passing rate (p=0.55).Conclusions:Feature matching provides a quantitative assessment of deformable image registration, with a large number of data points for analysis. The TRE of matched features can be used to evaluate the registration of many objects throughout the volume, whereas DSC mainly provides a measure of gross overlap.We have a research agreement with ViewRay Inc.
TU‐AB‐202‐07: A Novel Method for Registration of Mid‐Treatment PET/CT Images Under Conditions of Tumor Regression for Patients with Locally Advanced Lung Cancers
Authors: Sharifi Hoda , Zhang Hong , Jin Jian‐Yyue , Kong Feng‐Ming , Chetty Indrin J , Zhong Hualiang 
Published: July 2016

Purpose:In PET‐guided adaptive radiotherapy (RT), changes in the metabolic activity at individual voxels cannot be derived until the duringtreatment CT images are appropriately registered to pre‐treatment CT images. However, deformable image registration (DIR) usually does not preserve tumor volume. This may induce errors when comparing to the target. The aim of this study was to develop a DIR‐integrated mechanical modeling technique to track radiation‐induced metabolic changes on PET images.Methods:Three patients with non‐small cell lung cancer (NSCLC) were treated with adaptive radiotherapy under RTOG 1106. Two PET/CT image sets were acquired 2 weeks before RT and 18 fractions after the start of treatment. DIR was performed to register the during‐RT CT to the pre‐RT CT using a B‐spline algorithm and the resultant displacements in the region of tumor were remodeled using a hybrid finite element method (FEM). Gross tumor volume (GTV) was delineated on the during‐RT PET/CT image sets and deformed using the 3D deformation vector fields generated by the CT‐based registrations. Metabolic tumor volume (MTV) was calculated using the pre‐ and during–RT image set. The quality of the PET mapping was evaluated based on the constancy of the mapped MTV and landmark comparison.Results:The B‐spline‐based registrations changed MTVs by 7.3%, 4.6% and −5.9% for the 3 patients and the correspondent changes for the hybrid FEM method −2.9%, 1% and 6.3%, respectively. Landmark comparisons were used to evaluate the Rigid, B‐Spline, and hybrid FEM registrations with the mean errors of 10.1 ± 1.6 mm, 4.4 ± 0.4 mm, and 3.6 ± 0.4 mm for three patients. The hybrid FEM method outperforms the B‐Spline‐only registration for patients with tumor regressionConclusion:The hybrid FEM modeling technique improves the B‐Spline registrations in tumor regions. This technique may help compare metabolic activities between two PET/CT images with regressing tumors.The author gratefully acknowledges the financial support from the National Institutes of Health Grant
TU‐AB‐202‐08: Generating Organ Surfaces to Overcome Random Contouring Errors and Slice Thickness Variations On Multimodality Images
Authors: Oh S , Weiss E , Christensen G , Hugo G , Williamson J 
Published: July 2016

Purpose:To propose a new method that generates smooth organ surface meshes that overcomes random contouring errors and volume averaging artifacts for hollow organs.Methods:The proposed contour‐to‐smooth mesh generation method (CSMG) consists of two parts; 1) reconstructing the inner and outer surfaces of the hollow organ with triangular meshes based on parametric active surface (PAS) and 2) modifying the reconstructed inner surface in order to satisfy minimum wall thickness constraints and matching the patient's known organ wall volume. In both steps, PAS evolved gradually to physician contours by minimizing defined energy functions. CSMG surface meshes were evaluated using two digital phantoms and 72 contours from 3 cervix cancer patients (4 images per patient, 3 organs per image, 2 inner‐and‐outer‐wall contours per organ). The CSMG and treatment planning system (TPS) surface meshes were compared using Gaussian curvature, Dice conformity index (DCI) and signed minimum distance (SMD). DCI and SMD were calculated between the physician contours and the contour extracted by averaging the surface over the slice thickness.Results:CSMG meshes were smoother and more continuous than TPS surface meshes. The DCI differences between CSMG and TPS were 0.2%, 0.9% and 1.5% on average for bladder, rectum and vagina, respectively. TPS meshes had larger average SMDs (0.44±0.64, 0.43±0.62 and 0.42±0.61 mm for the three organs) compared to CSMG meshes (0.01±0.84, −0.05±0.93 and 0.13±0.91 mm). Larger grand mean and smaller pooled standard deviation of TPS SMDs implied that TPS overfitted the noise on contours but PM smoothed out the noise. The wall thicknesses were 2.7±1.3, 2.6±1.1 and 1.6±0.5 mm for bladder, rectum and vagina, respectively. The wall volume differed from reference volume less than ±2.5%.Conclusion:The proposed method reconstructs the smooth and continuous organ surface from sparsely sampled data points without introducing large systematic errors.This work was supported in part by Varian Research agreement. The authors have the following disclosures: NIH (Williamson, Hugo, Christensen, and Weiss), Philips research agreement (Hugo and Weiss), Varian license agreement (Hugo and Weiss), Roger Koch fund (Christensen), UpToDate royalties (Weiss). There is no COI.
TU‐AB‐202‐11: Tumor Segmentation by Fusion of Multi‐Tracer PET Images Using Copula Based Statistical Methods
Authors: Lapuyade‐Lahorgue J , Ruan S , Li H , Vera P 
Published: July 2016

Purpose:Multi‐tracer PET imaging is getting more attention in radiotherapy by providing additional tumor volume information such as glucose and oxygenation. However, automatic PET‐based tumor segmentation is still a very challenging problem. We propose a statistical fusion approach to joint segment the sub‐area of tumors from the two tracers FDG and FMISO PET images.Methods:Non‐standardized Gamma distributions are convenient to model intensity distributions in PET. As a serious correlation exists in multi‐tracer PET images, we proposed a new fusion method based on copula which is capable to represent dependency between different tracers. The Hidden Markov Field (HMF) model is used to represent spatial relationship between PET image voxels and statistical dynamics of intensities for each modality. Real PET images of five patients with FDG and FMISO are used to evaluate quantitatively and qualitatively our method. A comparison between individual and multi‐tracer segmentations was conducted to show advantages of the proposed fusion method.Results:The segmentation results show that fusion with Gaussian copula can receive high Dice coefficient of 0.84 compared to that of 0.54 and 0.3 of monomodal segmentation results based on individual segmentation of FDG and FMISO PET images. In addition, high correlation coefficients (0.75 to 0.91) for the Gaussian copula for all five testing patients indicates the dependency between tumor regions in the multi‐tracer PET images.Conclusion:This study shows that using multi‐tracer PET imaging can efficiently improve the segmentation of tumor region where hypoxia and glucidic consumption are present at the same time. Introduction of copulas for modeling the dependency between two tracers can simultaneously take into account information from both tracers and deal with two pathological phenomena. Future work will be to consider other families of copula such as spherical and archimedian copulas, and to eliminate partial volume effect by considering dependency between neighboring voxels.
TU‐AB‐202‐12: A Novel Method to Map Endoscopic Video to CT for Treatment Planning and Toxicity Analysis in Radiation Therapy
Authors: Ingram W , Yang J , Beadle B , Wendt R , Rao A , Court L 
Published: July 2016

Purpose:Endoscopic examinations are routine procedures for head‐and‐neck cancer patients. Our goal is to develop a method to map the recorded video to CT, providing valuable information for radiotherapy treatment planning and toxicity analysis.Methods:We map video frames to CT via virtual endoscopic images rendered at the real endoscope's CT‐space coordinates. We developed two complementary methods to find these coordinates by maximizing real‐to‐virtual image similarity:(1)Endoscope Tracking: moves the virtual endoscope frame‐by‐frame until the desired frame is reached. Utilizes prior knowledge of endoscope coordinates, but sensitive to local optima. (2)Location Search: moves the virtual endoscope along possible paths through the volume to find the desired frame. More robust, but more computationally expensive. We tested these methods on clay phantoms with embedded markers for point mapping and protruding bolus material for contour mapping, and we assessed them qualitatively on three patient exams. For mapped points we calculated 3D‐distance errors, and for mapped contours we calculated mean absolute distances (MAD) from CT contours.Results:In phantoms, Endoscope Tracking had average point error=0.66±0.50cm and average bolus MAD=0.74±0.37cm for the first 80% of each video. After that the virtual endoscope got lost, increasing these values to 4.73±1.69cm and 4.06±0.30cm. Location Search had point error=0.49±0.44cm and MAD=0.53±0.28cm. Point errors were larger where the endoscope viewed the surface at shallow angles<10 degrees (1.38±0.62cm and 1.22±0.69cm for Endoscope Tracking and Location Search, respectively). In patients, Endoscope Tracking did not make it past the nasal cavity. However, Location Search found coordinates near the correct location for 70% of test frames. Its performance was best near the epiglottis and in the nasal cavity.Conclusion:Location Search is a robust and accurate technique to map endoscopic video to CT. Endoscope Tracking is sensitive to erratic camera motion and local optima, but could be used in conjunction with anchor points found using Location Search.
TU‐A‐206‐01: Professional Liability Insurance ‐ Protecting You and Your Practice
Authors: Fuller G. 
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‐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‐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 involvedConclusion: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 physicistAttendees 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 involvedConclusion: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 physicistAttendees 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.