bluuebunny/crossref_metadata_2025_split huggingface dataset:
MO‐B‐BRB‐03: 3D Dosimetry in the Clinic: Validating Special Techniques
Authors: Juang T. 
Published: July 2016

Full three‐dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging.In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques.

Learning Objectives:
L. John Schreiner: Background and Motivation

Understand recent developments enabling clinically practical 3D dosimetry,
Appreciate 3D dosimetry workflow and dosimetry procedures, and
Observe select examples from the clinic.
Sofie Ceberg: Application to dynamic radiotherapy

Observe full dosimetry under dynamic radiotherapy during respiratory motion, and
Understand how the measurement of high resolution dose data in an irradiated volume can help understand interplay effects during TomoTherapy or VMAT.
Titania Juang: Special techniques in the clinic and research

Understand the potential for 3D dosimetry in validating dose accumulation in deformable systems, and
Observe the benefits of high resolution measurements for precision therapy in SRS and in MicroSBRT for small animal irradiators
Geoffrey S. Ibbott: 3D Dosimetry in end‐to‐end dosimetry QA

Understand the potential for 3D dosimetry for end‐to‐end radiation therapy process validation in the in‐house and external credentialing setting.Canadian Institutes of Health Research; L. Schreiner, Modus QA, London, ON, Canada; T. Juang, NIH R01CA100835
MO‐B‐209‐01: Certificate Extension Process for DBT and the Medical Physicist's Role
Authors: Chakrabarti K. 
Published: July 2016

This presentation will describe the role of medical physicists during FDA's certificate extension process (CE). The presentation will outline FDA's CE process, with detailed discussions on training, MEE, and requirements for continued QA for the facility, vis‐a‐vis medical physicist's responsibilities. A few important tests will be discussed that need special emphasis for each of the DBT systems currently approved by FDA. What can be accepted as additional didactic and hands on training in fulfilling modality related training will be explained.

Learning Objectives:
Understand the certificate extension process
Understand medical physicist's responsibility in performing QC tests following the QC manual
Learn about proper presentation of data in reporting and generating soft copy phantom image
Understand on‐going responsibilities in monitoring QC technologists’ tests
MO‐DE‐204‐04: Dose Optimization in CT: Trends and Motivation in the US
Authors: Kofler J. 
Published: July 2016

The main topic of the session is to show how dose optimization is being implemented in various regions of the world, including Europe, Australia, North America and other regions.A multi‐national study conducted under International Atomic Energy Agency (IAEA) across more than 50 less resourced countries gave insight into patient radiation doses and safety practices in CT, mammography, radiography and interventional procedures, both for children and adults. An important outcome was the capability development on dose assessment and management.An overview of recent European projects related to CT radiation dose and optimization both to adults and children will be presented. Existing data on DRLs together with a European methodology proposed on establishing and using DRLs for paediatric radiodiagnostic imaging and interventional radiology practices will be shown.Compared with much of Europe at least, many Australian imaging practices are relatively new to the task of diagnostic imaging dose optimisation. In 2008 the Australian Government prescribed a requirement to periodically compare patient radiation doses with diagnostic reference levels (DRLs), where DRLs have been established. Until recently, Australia had only established DRLs for computed tomography (CT). Regardless, both professional society and individual efforts to improved data collection and develop optimisation strategies across a range of modalities continues. Progress in this field, principally with respect to CT and interventional fluoroscopy will be presented.In the US, dose reduction and optimization efforts for computed tomography have been promoted and mandated by several organizations and accrediting entities. This presentation will cover the general motivation, implementation, and implications of such efforts.

Learning Objectives:
Understand importance of the dose optimization in Diagnostic Radiology.
See how this goal is achieved in different regions of the World.
Learn about the global trend in the dose optimization and future prospectives.M. Rehani, The work was a part of the work of IAEA where I was an employee and IAEA is a United Nations organization
MO‐C‐BRB‐00: President's Symposium: Inspiring Leadership
Authors: Curran Bruce 
Published: July 2016

With the profound changes currently occurring in medicine, the role of the medical physicist cannot stagnate, but must evolve to meet the challenges and opportunities that are presented. Medical physicists must understand these changes and establish themselves not only as relevant but as leaders in this new environment. We must increase our presence in clinical settings such as tumor boards, patient rounds, and the development of new diagnosis, imaging, and treatment techniques. By establishing ourselves as competent scientists, we can and must participate in the development of technologies through research, teaching, and clinical implementation. As medical physicists we must define our roles and value to our physician colleagues, patients, referring physicians, and senior administrators. We cannot afford to be viewed solely as quality assurance technologists, but need to move forward in step with medical and practice advances, becoming recognized as having a leadership role in providing quality research, technological development, and quality patient care.In this session, four leaders in medical research and healthcare will discuss their observations on how medical physicists have contributed to advancements in healthcare and opportunities to continue leadership in providing quality medicine through the applications of physics to research, education, and clinical practice.

Learning Objectives:
Understand the changes in the healthcare environment and how medical physicists can contribute to improving patient care.
Learn how medical physicists are currently leading research efforts to improve clinical imaging and diagnosis.
Understand the role of medical physicists in developing new technology and leading its translation into clinical care.
MO‐D‐BRB‐00: SBRT Workflow Overview
Authors: Xing Lei 
Published: July 2016

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image‐guided patient setup and on‐treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real‐time image guidance during SBRT dose delivery using gated/un‐gated VMAT/IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state‐of‐art imaging and planning techniques.

Learning Objectives:
Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA.
Update on the use of multi‐dimensional and multi‐modality imaging for reliable guidance of SBRT.
Discuss treatment planning and QA issues specific to SBRT.
Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT.NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems
MO‐DE‐BRA‐01: Flipped Physics Courses Within a Radiologic Technologist Program: Video Production and Long Term Outcomes
Authors: Oshiro T , Donaghy M , Slechta A 
Published: July 2016

Purpose:To determine if the flipped class format has an effect on examination results for a radiologic technologist (RT) program and discuss benefits from creating video resources.Methods:From 2001–2015, students had taken both a radiological physics and quality control (QC) class as a part of their didactic training. In 2005/2006, the creation of videos of didactic lectures and QC test demonstrations allowed for a flip where content was studied at home while exercises and reviews were done in‐class. Final examinations were retrospectively reviewed from this timeframe. 12 multiple choice physics questions (MCP) and 5 short answer QC questions (SAQC) were common to pre and post flip exams. The RT program's ARRT exam scores were also obtained and compared to national averages.Results:In total, 36 lecture videos and 65 quality control videos were created for the flipped content. Data was ∼2.4GB and distributed to students via USB or CD media. For MCP questions, scores improved by 7.9% with the flipped format and significance (Student's t‐test, p<0.05) was found for 3 of the 12 questions. SAQC questions showed improvement by 14.6% and significance was found for 2 of the 5 questions. Student enrollment increased from ∼14 (2001–2004) to ∼23 students (2005–15). Content was continuously added post‐flip due to the efficiency of delivery. The QC class in 2003 covered 45 test setups in‐class while 65 were covered with video segments in 2014. Flipped materials are currently being repurposed. In 2015, this video content was restructured into an ARRT exam review guide and in 2016, the content was reorganized for fluoroscopy training for physicians.Conclusion:We believe that flipped classes can improve efficiency of content delivery and improve student performance even with an increase in class size. This format allows for flexibility in learning as well as re‐use in multiple applications.
TU‐A‐BRB‐03: Panel Member
Authors: Winey B. 
Published: July 2016

Brain stereotactic radiosurgery (SRS) and spine stereotactic body radiation therapy (SBRT) are commonly treated by a multidisciplinary team of neurosurgeons, radiation oncologists, and medical physicists. However the treatment objectives, constraints, and technical considerations involved can be quite different between the two techniques. In this interactive session an expert panel of speakers will present clinical brain SRS and spine SBRT cases in order to demonstrate real‐world considerations for ensuring safe and accurate treatment delivery and to highlight the significant differences in approach for each treatment site. The session will include discussion of topic such as clinical indications, immobilization, target definition, normal tissue tolerance limits, and beam arrangements.

Learning Objectives:
Understand the differences in indications and dose/fractionation strategies for intracranial SRS and spine SBRT.
Describe the different treatment modalities which can be used to deliver intracranial SRS and spine SBRT.
Cite the major differences in treatment setup and delivery principles between intracranial and spine treatments.
Identify key critical structures and clinical dosimetric tolerance levels for spine SBRT and intracranial SRS.
Understand areas of ongoing work to standardize intracranial SRS and spine SBRT procedures.Schlesinger: Research support: Elekta Instruments, AB; D. Schlesinger, Elekta Instruments, AB ‐ research support; B. Winey, No relevant external funding for this subject.
TU‐AB‐BRA‐04: An Investigation of Metal Artifact Effects in Multi‐Modalities: Development of MRI‐CT Heterogeneous Head and Neck Phantom for MRI‐CT Registration
Authors: Lee M , Song K , Choe B , Suh T 
Published: July 2016

Purpose:The purpose of this investigation was to develop an CT‐MR head and neck phantom which can investigate dose calculation differences between density‐assigned MRI and CT, and to compare non‐implant inserted registered MR‐CT registered image with artifact reduced image of MR‐CT registered image. It is to identify potential limitations related to dental implants of MR image and CT image and maximize the advantages to find interactive method to use registered image.Methods:The phantom comprises half‐circled shape which shaped to simulated the anatomical structures of a human head and neck. Through applying various clinical cases, the developed phantom is closely allied to human. Developed phantom can be verified in to opened‐mouth and closed‐mouth phantom. The case of the phantom was made of acrylic, which introduces a 0.003 parts per million (ppm) phase shift, whereas the Teflon results in a 0.03 ppm shift measured at 3T which represents human bone. Both materials are considered acceptable for MR field measurements. The phantom was filled with a solution of nickel chloride and sodium chloride. The implants and teeth were imaged by means of 3T MRI system.Results:In MRI image, the metal artifact reduced and the results in improved image quality and reduction of susceptibility artifacts originate in MR images. CT and MR artifact correction method resulted in substantial artifact reduction, both quantitatively and qualitatively. On head and neck CT images, it remained anatomical conformation but it has reduced streak and dark artifact which appeared around the dental restoration. The artifact reduced MR‐CT image improved image quality and calculation accuracy for patients with severe CT artifacts.Conclusion:By using MRI/CT and the artifact‐free slice location of the phantom, we demonstrated that the proposed artifact reduction method can effectively remove streak artifacts from a metal object.
TU‐AB‐BRA‐06: BEST IN PHYSICS (JOINT IMAGING‐THERAPY): An MRI Compatible Externally and Internally Deformable Lung Motion Phantom for Multi‐Modality IGRT
Authors: Sabouri P , Arai T , Sawant A 
Published: July 2016

Purpose:MRI has become an attractive tool for tumor motion management. Current MR‐compatible phantoms are only capable of reproducing translational motion. This study describes the construction and validation of a more realistic, MRI‐compatible lung phantom that is deformable internally as well as externally. We demonstrate a radiotherapy application of this phantom by validating the geometric accuracy of the open‐source deformable image registration software NiftyReg (UCL, UK).Methods:The outer shell of a commercially‐available dynamic breathing torso phantom was filled with natural latex foam with eleven water tubes. A rigid foam cut‐out served as the diaphragm. A high‐precision programmable, in‐house, MRI‐compatible motion platform was used to drive the diaphragm. The phantom was imaged on a 3T scanner (Philips, Ingenia). Twenty seven tumor traces previously recorded from lung cancer patients were programmed into the phantom and 2D+t image sequences were acquired using a sparse‐sampling sequence k‐t BLAST (accn=3, resolution=0.66×0.66×5mm3; acquisition‐time=110ms/slice). The geometric fidelity of the MRI‐derived trajectories was validated against those obtained via fluoroscopy using the on board kV imager on a Truebeam linac. NiftyReg was used to perform frame by frame deformable image registration. The location of each marker predicted by using NiftyReg was compared with the values calculated by intensity‐based segmentation on each frame.Results:In all cases, MR trajectories were within 1 mm of corresponding fluoroscopy trajectories. RMSE between centroid positions obtained from segmentation with those obtained by NiftyReg varies from 0.1 to 0.21 mm in the SI direction and 0.08 to 0.13 mm in the LR direction showing the high accuracy of deformable registration.Conclusion:We have successfully designed and demonstrated a phantom that can accurately reproduce deformable motion under a variety of imaging modalities including MRI, CT and x‐ray fluodoscopy, making it an invaluable research tool for validating novel motion management strategies.This work was partially supported through research funding from National Institutes of Health (R01CA169102).
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.