bluuebunny/crossref_metadata_2025_split huggingface dataset:
TH‐E‐201‐01: Diagnostic Radiology Residents Physics Curriculum and Updates
Authors: Sensakovic W. 
Published: July 2016

The ABR Core Examination stresses integrating physics into real‐world clinical practice and, accordingly, has shifted its focus from passive recall of facts to active application of physics principles. Physics education of radiology residents poses a challenge. The traditional method of didactic lectures alone is insufficient, yet it is difficult to incorporate physics teaching consistently into clinical rotations due to time constraints.Faced with this challenge, diagnostic medical physicists who teach radiology residents, have been thinking about how to adapt their teaching to the new paradigm, what to teach and meet expectation of the radiology resident and the radiology residency program. The proposed lecture attempts to discuss above questions. Newly developed diagnostic radiology residents physics curriculum by the AAPM Imaging Physics Curricula Subcommittee will be reviewed. Initial experience on hands‐on physics teaching will be discussed. Radiology resident who will have taken the BAR Core Examination will share the expectation of physics teaching from a resident perspective.The lecture will help develop robust educational approaches to prepare radiology residents for safer and more effective lifelong practice.

Learning Objectives:
Learn updated physics requirements for radiology residents
Pursue effective approaches to teach physics to radiology residents
Learn expectation of physics teaching from resident perspectiveJ. Zhang, This topic is partially supported by RSNA Education Scholar Grant
TH‐E‐201‐03: A Radiology Resident's Perspectives of Physics Teaching
Authors: Key A. 
Published: July 2016

The ABR Core Examination stresses integrating physics into real‐world clinical practice and, accordingly, has shifted its focus from passive recall of facts to active application of physics principles. Physics education of radiology residents poses a challenge. The traditional method of didactic lectures alone is insufficient, yet it is difficult to incorporate physics teaching consistently into clinical rotations due to time constraints.Faced with this challenge, diagnostic medical physicists who teach radiology residents, have been thinking about how to adapt their teaching to the new paradigm, what to teach and meet expectation of the radiology resident and the radiology residency program. The proposed lecture attempts to discuss above questions. Newly developed diagnostic radiology residents physics curriculum by the AAPM Imaging Physics Curricula Subcommittee will be reviewed. Initial experience on hands‐on physics teaching will be discussed. Radiology resident who will have taken the BAR Core Examination will share the expectation of physics teaching from a resident perspective.The lecture will help develop robust educational approaches to prepare radiology residents for safer and more effective lifelong practice.

Learning Objectives:
Learn updated physics requirements for radiology residents
Pursue effective approaches to teach physics to radiology residents
Learn expectation of physics teaching from resident perspectiveJ. Zhang, This topic is partially supported by RSNA Education Scholar Grant
TH‐EF‐204‐01: Introduction
Authors: Cygler J. 
Published: July 2016

Joanna E. Cygler, Jan Seuntjens, J. Daniel Bourland, M. Saiful Huq, Josep Puxeu Vaque, Daniel Zucca Aparicio, Tatiana Krylova, Yuri Kirpichev, Eric Ford, Caridad BorrasStereotactic Radiation Therapy (SRT) utilizes small static and dynamic (IMRT) fields, to successfully treat malignant and benign diseases using techniques such as Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT). SRT is characterized by sharp dose gradients for individual fields and their resultant dose distributions. For appropriate targets, small field radiotherapy offers improved treatment quality by allowing better sparing of organs at risk while delivering the prescribed target dose. Specialized small field treatment delivery systems, such as robotic‐controlled linear accelerators, gamma radiosurgery units, and dynamic arc linear accelerators may utilize rigid fixation, image guidance, and tumor tracking, to insure precise dose delivery to static or moving targets. However, in addition to great advantages, small field delivery techniques present special technical challenges for dose calibration due to unique geometries and small field sizes not covered by existing reference dosimetry protocols such as AAPM TG‐51 or IAEA TRS 398. In recent years extensive research has been performed to understand small field dosimetry and measurement instrumentation. AAPM, IAEA and ICRU task groups are expected to provide soon recommendations on the dosimetry of small radiation fields. In this symposium we will: 1] discuss the physics, instrumentation, methodologies and challenges for small field radiation dose measurements; 2] review IAEA and ICRU recommendations on prescribing, recording and reporting of small field radiation therapy; 3] discuss selected clinical applications and technical aspects for specialized image‐guided, small field, linear accelerator based treatment techniques such as IMRT and SBRT.

Learning Objectives:
To learn the physics of small fields in contrast to dosimetry of conventional fields
To learn about detectors suitable for small fields
To learn about the role of Monte Carlo simulations in determination of small field output factors
To provide an overview of the IAEA small field dosimetry recommendations
To provide an overview of the content of the ICRU report on Prescribing, Reporting and Recording of Small Field Radiation Therapy.
To learn about special technical considerations in delivering IMRT and SBRT treatments
To appreciate specific challenges of IMRT implementationJ. Seuntjens, Natural Sciences and Engineering Research Council; Canadian Institutes of Health Research
TH‐EF‐BRB‐05: 4pi Non‐Coplanar IMRT Beam Angle Selection by Convex Optimization with Group Sparsity Penalty
Authors: O'Connor D , Voronenko Y , Nguyen D , Yin W , Sheng K 
Published: July 2016

Purpose:Integrated beam orientation and fluence map optimization is expected to be the foundation of robust automated planning but existing heuristic methods do not promise global optimality. We aim to develop a new method for beam angle selection in 4π non‐coplanar IMRT systems based on solving (globally) a single convex optimization problem, and to demonstrate the effectiveness of the method by comparison with a state of the art column generation method for 4π beam angle selection.Methods:The beam angle selection problem is formulated as a large scale convex fluence map optimization problem with an additional group sparsity term that encourages most candidate beams to be inactive. The optimization problem is solved using an accelerated first‐order method, the Fast Iterative Shrinkage‐Thresholding Algorithm (FISTA). The beam angle selection and fluence map optimization algorithm is used to create non‐coplanar 4π treatment plans for several cases (including head and neck, lung, and prostate cases) and the resulting treatment plans are compared with 4π treatment plans created using the column generation algorithm.Results:In our experiments the treatment plans created using the group sparsity method meet or exceed the dosimetric quality of plans created using the column generation algorithm, which was shown superior to clinical plans. Moreover, the group sparsity approach converges in about 3 minutes in these cases, as compared with runtimes of a few hours for the column generation method.Conclusion:This work demonstrates the first non‐greedy approach to non‐coplanar beam angle selection, based on convex optimization, for 4π IMRT systems. The method given here improves both treatment plan quality and runtime as compared with a state of the art column generation algorithm. When the group sparsity term is set to zero, we obtain an excellent method for fluence map optimization, useful when beam angles have already been selected.NIH R43CA183390, NIH R01CA188300, Varian Medical Systems; Part of this research took place while D. O'Connor was a summer intern at RefleXion Medical.
TH‐EF‐BRB‐06: Implementation of a Modulated‐Arc Total Body Irradiation (TBI) Technique Using the RayStation Treatment Planning System
Authors: Phillips J , Cheung J , Held M , Han D , Morin O 
Published: July 2016

Purpose:To develop a clinical workflow for delivering a modulated‐arc total body irradiation (TBI) with RayStation scripting. This technique uses arc fields with the patient lying at floor level on a padded table and is validated through measurements taken on a custom‐made TBI phantom.Methods:Treatment planning was performed for a retrospective cohort of eight patients with a diverse range of heights and body types. Each was replanned using an open‐field dual arc method, with the patient in supine and prone positions on the floor of the vault. All plans were optimized using Raystation Planning 4.7.2.5 (RaySearch Laboratories, Stockholm, Sweden), with 200 cGy prescribed to the 95% of the body contour − 5mm. This results in an open‐field beam that sweeps craniocaudally across the length of the patient. The technique is validated with measurements at 10 cm intervals in a custom‐milled, 5 cm thick acrylic phantom. A centrally located CC13 ion chamber and a Mobile MOSFET (Best Medical Canada, Ottawa, ON) detector array were used to measure dose. Supine and prone arcs for each patient were consecutively delivered, and the aggregate dose at each point was compared to the planned dose calculated in the phantom.Results:The ion chamber measurements differed from the planned dose by an average of .5%, with a standard deviation of 2.1%. All measured data for the MOSFETS were within 10% of the corresponding planned dose except for two outlying points. The standard deviation of dose differences across the entire cohort was 4.0%. Most significant discrepancies occurred either in inhomogeneous regions with large gradients, or at inferior points where beam angle was steepest.Conclusion:We have confirmed that the planned dose is well matched to our measurements within 10% for this method of planning and delivery. We are currently incorporating this technique into our clinical workflow.This work is supported by RaySearch.
TH‐EF‐BRA‐02: A Novel Markerless 4D CBCT Projection Phase Sorting Technique Using Prior Knowledge and Patient Motion Modeling: A Feasibility Study
Authors: Zhang L , Zhang Y , Yin F , Harris W , Cai J , Ren L 
Published: July 2016

Purpose:To investigate the feasibility of a novel marker‐less motion‐modeling based method for automatic 4D‐CBCT projection phase sorting.Methods:Patient on‐board image volume at any instant is considered as a deformation of one phase of the prior planning 4D‐CT. The deformation field map(DFM) is represented as a linear combination of three major deformation patterns extracted from the planning 4D‐CT using principle‐component‐analysis(PCA). The PCA coefficients are solved for each single projection based on data fidelity constraint, and are used as motion information for phase sorting. Projections at the valleys of the Z direction coefficient are sorted as phase 0/100% and projection phases in between are linearly interpolated. 4D‐digital‐extended‐cardiac‐torso(XCAT) phantoms and 3 patient cases were used for evaluation. XCAT phantoms simulated different patient respiratory and anatomical changes from prior 4D‐CT to on‐board image volume, including changes of tumor size, locations, motion amplitudes and motion directions. Three patient cases include 2 full‐fan slow‐rotation and one half‐fan normal‐rotation case. Manual phase sorting based on visual inspection was used as the gold standard. The average absolute phase difference, and the pass rate (percentage of projections sorted within 10% phase error) were used to evaluate sorting accuracy.Results:The amplitude of PCA coefficient motion curve correlated with the actual motion amplitude. The algorithm was robust against respiratory and anatomical changes from prior to on‐board imaging. For all XCAT cases, the average phase errors were lower than 1.43%, and the pass rate was 100%. The patient data set showed average phase error of 2.47%, 1.90% for full fan slow rotation case and 2.78% for half fan normal rotation case, respectively. The corresponding pass rates were 99.4%, 98.5% and 99.5%, respectively.Conclusion:Preliminary results demonstrated the robustness and high accuracy of the marker‐less PCA based phase sorting algorithm for different patient scenarios and 4D‐CBCT scanning protocols.
TH‐EF‐BRA‐03: Assessment of Data‐Driven Respiratory Motion‐Compensation Methods for 4D‐CBCT Image Registration and Reconstruction Using Clinical Datasets
Authors: Riblett MJ , Weiss E , Christensen GE , Hugo GD 
Published: July 2016

Purpose:To evaluate the performance of a 4D‐CBCT registration and reconstruction method that corrects for respiratory motion and enhances image quality under clinically relevant conditions.Methods:Building on previous work, which tested feasibility of a motion‐compensation workflow using image datasets superior to clinical acquisitions, this study assesses workflow performance under clinical conditions in terms of image quality improvement. Evaluated workflows utilized a combination of groupwise deformable image registration (DIR) and image reconstruction. Four‐dimensional cone beam CT (4D‐CBCT) FDK reconstructions were registered to either mean or respiratory phase reference frame images to model respiratory motion. The resulting 4D transformation was used to deform projection data during the FDK backprojection operation to create a motion‐compensated reconstruction. To simulate clinically realistic conditions, superior quality projection datasets were sampled using a phase‐binned striding method. Tissue interface sharpness (TIS) was defined as the slope of a sigmoid curve fit to the lung‐diaphragm boundary or to the carina tissue‐airway boundary when no diaphragm was discernable. Image quality improvement was assessed in 19 clinical cases by evaluating mitigation of view‐aliasing artifacts, tissue interface sharpness recovery, and noise reduction.Results:For clinical datasets, evaluated average TIS recovery relative to base 4D‐CBCT reconstructions was observed to be 87% using fixed‐frame registration alone; 87% using fixed‐frame with motion‐compensated reconstruction; 92% using mean‐frame registration alone; and 90% using mean‐frame with motion‐compensated reconstruction. Soft tissue noise was reduced on average by 43% and 44% for the fixed‐frame registration and registration with motion‐compensation methods, respectively, and by 40% and 42% for the corresponding mean‐frame methods. Considerable reductions in view aliasing artifacts were observed for each method.Conclusion:Data‐driven groupwise registration and motion‐compensated reconstruction have the potential to improve the quality of 4D‐CBCT images acquired under clinical conditions. For clinical image datasets, the addition of motion compensation after groupwise registration visibly reduced artifact impact.This work was supported by the National Cancer Institute of the National Institutes of Health under Award Number R01CA166119. Hugo and Weiss hold a research agreement with Philips Healthcare and license agreement with Varian Medical Systems. Weiss receives royalties from UpToDate. Christensen receives funds from Roger Koch to support research.
TH‐E‐202‐01: Pitfalls and Remedies in PET/CT Imaging for RT Planning
Authors: Pan T. 
Published: July 2016

PET/CT is a very important imaging tool in the management of oncology patients. PET/CT has been applied for treatment planning and response evaluation in radiation therapy. This educational session will discuss:

Pitfalls and remedies in PET/CT imaging for RT planning
The use of hypoxia PET imaging for radiotherapy
PET for tumor response evaluationThe first presentation will address the issue of mis‐registration between the CT and PET images in the thorax and the abdomen. We will discuss the challenges of respiratory gating and introduce an average CT technique to improve the registration for dose calculation and image‐guidance in radiation therapy. The second presentation will discuss the use of hypoxia PET Imaging for radiation therapy. We will discuss various hypoxia radiotracers, the choice of clinical acquisition protocol (in particular a single late static acquisition versus a dynamic acquisition), and the compartmental modeling with different transfer rate constants explained. We will demonstrate applications of hypoxia imaging for dose escalation/de‐escalation in clinical trials. The last presentation will discuss the use of PET/CT for tumor response evaluation. We will discuss anatomic response assessment vs. metabolic response assessment, visual evaluation and semi‐quantitative evaluation, and limitations of current PET/CT assessment. We will summarize clinical trials using PET response in guiding adaptive radiotherapy. Finally, we will summarize recent advancements in PET/CT radiomics and non‐FDG PET tracers for response assessment.

Learning Objectives:
Identify the causes of mis‐registration of CT and PET images in PET/CT, and review the strategies to remedy the issue.
Understand the basics of PET imaging of tumor hypoxia (radiotracers, how PET measures the hypoxia selective uptake, imaging protocols, applications in chemo‐radiation therapy).
Understand the basics of dynamic PET imaging, compartmental modeling and parametric images.
Understand the basics of using FDG PET/CT for tumor response evaluation.
Learn about recent advancement in PET/CT radiomics and non‐FDG PET tracers for response assessment.This work was supported in part by the National Cancer Institute Grants R01CA172638.; W. Lu, This work was supported in part by the National Cancer Institute Grants R01CA172638.
TH‐EF‐207A‐06: High‐Resolution Optical‐CT/ECT Imaging of Unstained Mice Femur, Brain, Spleen, and Tumor
Authors: Yoon S , Boss M , Birer S , Dewhirst M , Oldham M 
Published: July 2016

Purpose:Optical transmission and emission computed tomography (optical‐CT/ECT) provides high‐resolution 3D attenuation and emission maps in unsectioned large (∼1cm3) ex vivo tissue samples at a resolution of 12.9µm3 per voxel. Here we apply optical‐CT/ECT to investigate high‐resolution structure and auto‐fluorescence in a range of optically cleared mice organs, including, for the first time, mouse bone (femur), opening the potential for study of bone metastasis and bone‐mediated immune response.Methods:Three BALBc mice containing 4T1 flank tumors were sacrificed to obtain spleen, brain, tumor, and femur. Tissues were washed in 4% PFA, fixed in EtOH solution (for 5, 10, 10, and 2 days respectively), and then optically cleared for 3 days in BABBs. The femur was also placed in 0.25M aqueous EDTA for 15–30 days to remove calcium. Optical‐CT/ECT attenuation and emission maps at 633nm (the latter using 530nm excitation light) were obtained for all samples. Bi‐telecentric optical‐CT was compared side‐by‐side with conventional optical projection tomography (OPT) imaging to evaluate imaging capability of these two rival techniques.Results:Auto‐fluorescence mapping of femurs reveals vasculatures and fluorescence heterogeneity. High signals (A.U.=10) are reported in the medullary cavity but not in the cortical bone (A.U.=1). The brain strongly and uniform auto‐fluoresces (A.U.=5). Thick, optically dense organs such as the spleen and the tumor (0.12, 0.46OD/mm) are reconstructed at depth without significant loss of resolution, which we attribute to the bi‐telecentric optics of optical‐CT. The attenuation map of tumor reveals vasculature, attenuation heterogeneity, and possibly necrotic tissue.Conclusion:We demonstrate the feasibility of optical‐CT/ECT imaging of un‐sectioned mice bones (femurs) and spleen with high resolution. This result, and the characterization of unstained organs, are important steps enabling future studies involving optical‐CT/ECT applied to study metastasis and immunologic responses via fluorescence staining.
TH‐E‐209‐03: Development of An In‐House CT Dose Monitoring and Management System Based On Open‐Source Software Resources ‐‐ Pearls and Pitfalls
Authors: Zhang D. 
Published: July 2016

Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data‐driven protocol management and informed case follow up are now feasible.Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co‐exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex.Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home‐grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope.Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home‐grown IT solution and dose data analysis framework.

Learning Objectives:
Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice
Review examples of data available from a variety of systems and how it managed and conveyed.
Reflect on the role of the physicist in radiation dose awareness.