bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐C‐342‐01: Image Guidance During Minimally Invasive Cardiac Interventions : Beyond Fluoroscopy
Authors: Fahrig R 
Published: July 2008

Minimally invasive cardiac procedures using endovascular access have enabled treatment of patients that previously would have required open‐heart surgery. Such procedures are typically carried out in the interventional suite, with x‐ray fluoroscopy used to guide the placement of a catheter, followed by a phase of the procedure in which x‐ray fluoroscopy provides little to no information on the treatment. C‐arm CT has been under development since the early 90's, but has now entered a new phase as the ability to visualize soft tissue and low‐contrast lesions improves. By generating 3D images utilizing the x‐ray system in the interventional suite, the error prone and time‐consuming spatio‐temporal registration with prior CT or MRI exams can be avoided. However, C‐arm CT imaging in the presence of cardiac motion remains a challenge due to the slow rotation speed of the gantry, and the slow readout rates of the flat‐panel detectors. Three main data acquisition approaches to circumvent these limitations will be discussed: multi‐sweep retrospective ECG gating for myocardial visualization, single‐ or double‐sweep with volume image fusion for left atrium and pulmonary vein visualization and single‐sweep with retrospective gating for coronary artery visualization. Approaches to improve image quality, both hardware and software, such as optimized acquisition timing, motion compensation approaches and algorithms for non‐idealities such as x‐ray scatter, detector lag, limited field‐of‐view or angular coverage, data insufficiency and noise will be presented. With these developments the ultimate goal is to accomplish faster and more accurate catheter based interventions with an equivalent success rate as surgical procedures (80–90%). The C‐arm CT technology described here could eventually impact many minimally invasive procedures such as RF ablation for atrial fibrillation and coronary stenting, and also future procedures as they become available, such as endocardial injection of stem cells for treatment of myocardial infarction.Educational Objectives:1. Learn how 3D cardiac imaging is done in the interventional suite: acquisition protocols, injection protocols, challenges and solutions.2. Learn how image quality of 3D cardiac images can be improved using hardware and algorithm approaches.
TU‐C‐342‐02: Dual Energy CT: Promises and Challenges for Cardiovascular Imaging
Authors: McCollough C 
Published: July 2008

Dual‐energy CT can be expected to play a new and evolving role in cardiovascular imaging. Clinical uses already reported include 1) direct CT angiography, whereby the dual energy algorithm identifies and removes bone in a 3‐D CT angiographic data set, allowing direct visualization of iodinated vessels without the need for user intervention to remove overlying bony anatomy, 2) removal of smaller hard plaques within vessels, allowing more rapid and clearer visualization of patent lumens in MIP projections, and 3) visualization of the perfused blood volume, also referred to as blood pool imaging, to demonstrate focal perfusion deficits. Dual energy bone and plaque removal techniques can be applied in retrospectively‐gated cardiac imaging, suppressing the appearance of calcified plaque and providing improved visualization of stenotic lumens. Additionally, dual‐energy CT can be used to identify and remove calcified plaque prior to image reconstruction in order to reduce the effects of calcium blooming, which creates artifactual elevation of CT numbers in voxels adjacent to calcified objects, often obscuring the dimensions of the true lumen for large or dense coronary artery calcifications. Finally, using projection‐space dual‐energy methods, mono‐energetic CT images can be calculated, which greatly reduces beam hardening effects and increases the accuracy of CT number measurements. The use of dual‐energy CT techniques is being explored for the evaluation of myocardial perfusion deficits.Attendees of this presentation can expect to learn about:1) the technical approaches to dual‐energy cardiac CT currently implemented or under investigation on commercial CT systems,2) current clinical uses of dual‐energy CT in cardiovascular imaging and3) areas of future investigation.
TU‐D‐350‐02: Civil Law, Ethics and the Medical Physicist
Authors: Serago C 
Published: July 2008

Ethics Case Reports.Questionable ethical behavior may or may not also entail questionable lawful behavior. Several case reports are presented to differentiate legal and ethical issues. There is often an overlap of ethical and legal boundaries; so many situations may have both legal and ethical implications. The ramifications of legal vs. ethical violations are obviously different. Hypothetical case reports will include: hostile work environment, sexual harassment, graduate student progress impediments, substance abuse, and questionable practice.
TU‐D‐342‐02: What Every Medical Physicist Should Know About Breast Tomosynthesis
Authors: Lo JY 
Published: July 2008

Digital tomosynthesis (or “tomo”) is revolutionizing breast imaging. Based on modified full‐field digital mammography systems, breast tomo can achieve limited‐angle cone‐beam CT imaging which produces 3D slice images of the breast. This addresses the problem of overlapping dense tissue which is the most common cause for unnecessary callbacks as well as missed cancers in mammography screening. Tomo can provide 3D images while remaining comparable to mammography in terms of speed, resolution, cost, and dose. For these reasons, tomo may be only imaging technique with the potential to completely replace the current role of mammography as the primary tool in breast cancer screening and diagnosis. FDA approval is imminent, so it is all the more important for medical physicists to understand this new modality's potential as well as limitations.This presentation will cover both the hype and hope surrounding breast tomosynthesis. What do the initial clinical trials suggest about its performance? What are the on‐going physics issues in terms of clinical implementation, including compression, dose, and QA? What are some of the latest results from different research groups working on optimization of radiographic techniques, acquisition modes, and reconstruction algorithms? What is coming down the road in terms of advanced applications including quantitative imaging, computer aided detection, and contrast enhanced imaging? We will explore the answers to these and other questions together.The work discussed in this presentation was supported in part by grants from NIH/NCI, US Army Breast Cancer Research Program, Susan G. Komen for the Cure, General Electric Company, Hologic, and Siemens Medical Solutions.Educational Objectives:1. Understand the difference between breast tomosynthesis and dedicated breast CT.2. Appreciate the many medical physics issues involved in the development and optimization of breast tomosynthesis.3. Understand the clinical promise and concerns of using breast tomosynthesis.
TU‐EE‐A2‐05: Hypofractionation: What Does It Mean For Prostate Cancer Treatment?
Authors: Liao Y , Joiner M , Huang Y , Burmeister J 
Published: July 2008

Purpose: Using current radiobiological models, we quantitatively examined the predicted clinical consequences of hypofractionation in prostate cancer radiotherapy while varying biological indices such as α/β, SF2, and total dose and dose per fraction. Method and Materials: Four hypofractionated treatment regimens, 22×2.94Gy, 16×3.63Gy, 12×4.3Gy, and 5×6.7Gy, were compared with standard fractionation of 39×2Gy. All regimens produce similar EQD2 to the tumor assuming α/β=2.4Gy for prostate carcinoma. Actual α/β values ranging from 1.5 to 8.5Gy for prostate carcinoma and fixed α/β values of 4Gy for both rectum and bladder were used to calculate biologically relevant parameters. The LQ model and gEUD formalism were used to transform the physical dose distribution into normalized equivalent uniform dose (gEUD2), from which TCP and NTCP were calculated. Final ranking of the radiotherapy plans was based on “complication‐free tumor control probability”.Results: gEUD2 to rectum and bladder decreased by 28% and 23%, respectively, in the 6.7Gy/fraction regimen compared with 2Gy/fraction using “a”=5 for the gEUD calculation. A corresponding 10% decrease in NTCP was predicted for the 6.7Gy/fraction regimen compared with 2Gy/fraction. Conversely, predicted TCP for hypofractionated regimens decreases significantly with increasing SF2 and α/β. We found that for relatively responsive tumor cells (SF2=0.4–0.5), complication‐free tumor control probability was superior for nearly all hypofractionated regimens even for α/β values up to 8.5Gy. For less responsive tumor cells, (SF2=0.6), 6.7Gy/fx is predicted to be inferior to standard fractionation even when α/β=1.7Gy, and the other hypofractionation regimens remain superior to the standard fractionation for α/β values up to 3.5Gy. Conclusion: Existing radiobiological data and models predict better clinical results from hypofractionation than standard fractionation for prostate carcinoma when SF2<0.5 and <5×106 clonogenic cells, implying that it is superior for early stage disease. This is true even when tumor α/β is high.Part funded by Varian Medical Systems.
TU‐E‐AUD C‐01: Contemporary Concepts in Cellular and Molecular Biology for the Medical Physicist
Authors: Rosenstein B 
Published: July 2008

Progress in translational biomedical research, whose goal is to translate basic research findings from the laboratory into the clinic to improve patient care, depends extensively upon the use of molecular and cellular concepts and tools. Thus, research activities often focus upon the use of cellular and molecular biology to examine research questions with potential clinical implications. As such, medical physicists may be at somewhat of a loss to comprehend these studies since they are frequently not equipped with an understanding of these applications. This restricts the role for the medical physicist and often limits their participation in conferences and seminars, which is unfortunate since these individuals may be able to provide a key contribution to ongoing research activities. A knowledge of cellular and molecular biology is also important for clinical applications of therapies and diagnostics which rely upon an understanding of the biologic basis behind their effectiveness. The goal of this educational session is to provide medical physicists with a basic working knowledge of the most common and important contemporary cellular and molecular approaches used in translational biomedical research.Educational Objectives:1. To provide medical physicists with an understanding of the following topics in cellular and molecular biology:a. DNA, RNA and protein structure, synthesis and function.b. Vectors and recombinant moleculesReporter gene assays.c. Genetic libraries.d. Gel electrophoresis.e. Polymerase chain reactionf. Gene analyses; southern, northern and western blots.g. Microarrays.h. Single nucleotide polymorphisms.i. Knockout mice.j. EMSA, ELISA and immunoprecipitation.k. Monoclonal antibodies.l. Gene silencing.m. Detection and measurement of DNA damage.
TU‐E‐351‐01: Writing and Reviewing Medical Physics Papers
Authors: Hendee W , Slattery P , Karellas A , Rogers D 
Published: July 2008

There is an art to writing a scientific paper so that it communicates accurately, succinctly, and comprehensively. Developing this art comes with experience, and sharing that experience with younger physicists is an obligation of senior scientists, especially those with editorial responsibilities for the journal. In this workshop, the preparation of a scientific manuscript will be dissected so participants can appreciate how each part is developed and then assembled into a complete paper. Then the review process for the paper will be discussed, including how to examine a paper and write an insightful and constructive review. Finally, we will consider the challenge of accommodating the concerns and recommendations of a reviewer in preparing a revision of the paper.A second feature of the workshop will be a discussion of the process of electronic submission of a paper for consideration by Medical Physics. The web‐based PeerX‐Press engine for manuscript submission and management will be examined, with attention to special features such as EPAPS and line referencing. Finally, new features of Medical Physics will be explained, such as Vision 20/20 manuscripts, Physics Letters and the standardized formatting of book reviews.Education Objectives:1. Improve the participants' abilities to write a scientific manuscript.2. Understand the review process for Medical Physics manuscripts and how to participate in and benefit from it.3. Appreciate the many features of the PeerX‐Press electronic management process for Medical Physics manuscripts.4. Develop a knowledge of new features of Medical Physics.
WE‐E‐AUD B‐07: EGSnrc Benchmarking Against High‐Precision Angular Electron Scattering Data Through Thin Foils
Authors: Cojocaru C , Ross C , McEwen M , McDonald A , Faddegon B 
Published: July 2008

Purpose: The EGSnrc Monte Carlo code was benchmarked against newly measured angular scattering distributions of electron beams through thin materials. Method and Materials: The BEAMnrc user code was used for the simulation of the experimental setup. The geometry, beam and material properties were implemented in BEAMnrc, while the DOSXYZnrc user code was used to score the absorbed dose up to angles of 10°. The electron beam was generated using the National Research Council of Canada (NRC) Vickers linear accelerator, which allows for the production of narrow pencil beams of electrons with well known energies. Six materials: Be, C, Al, Ti, Cu, Ta and Au, were used as scattering foils and measurements were made at two energies — 13 MeV and 20 MeV. Great care was taken to obtain high accuracy experimental data for comparison with the results of the simulations. Results: The obtained angular distributions were fitted with a Gaussian and the characteristic angle (the angle at which the absorbed dose decreases by 1/e) was used to compare the measured and simulated distributions. The discrepancy between the measured and the EGSnrc characteristic angles is on average about 1.5%. A careful error estimation was performed on the measured data, that resulted in a value of about 1%. The EGSnrc code shows an agreement with the measured data at the 2σ level. In general, the EGSnrc predicts narrower distributions. The full distributions were also compared and the shapes were found to be very similar even at large angles. Conclusion: The present study shows that the EGSnrc code predicts electron angular scattering distributions in agreement with the measured data at the 2% level. It is intended to make the experimental data available to the user community to be used for benchmarking of other Monte Carlo codes.Partial support from NIH R01 CA104777‐01A2.
WE‐E‐AUD C‐07: A Robust Approach for Estimating Tumor Volume Change During Radiotherapy of Lung Cancer
Authors: ElNaqa I , Apte A , Yang D , Noel C , Bradle J , Deasy J 
Published: July 2008

Purpose: Radiotherapy treatment of lung cancer patients is complicated by changes in tumor position due to breathing and changes in size due to regression. Accurate quantification of these changes during the course of treatment would likely improve tumor response and reduce toxicity risks. We are investigating robust methods for tracking and estimating tumor volume changes between treatment fractions. Method and Materials: We have developed a registration—assisted segmentation approach based on the level‐set deformable model, in which pre‐treatment contours are propagated and adapted to fractions times at selected respiratory phases. At any time‐point during treatment, a reference respiratory phase is selected and corresponding 3D‐CT volumes are reconstructed from 4D‐CT acquisition data. Images are then globally aligned using an efficient registration algorithm. Pre‐treatment planning contours are copied to selected time‐points. In our tumor regression analysis, the GTV contour was used to initialize the level set algorithm in‐place and the PTV contour was used to narrowband the region, thus improving the algorithm's convergence. The feasibility of the proposed approach was investigated on a set of patients with repeated 4D scans acquired at three time‐intervals. Results: Our preliminary analysis indicates that the proposed approach can properly capture the boundary of the shrinking tumor region or split regions due to its topological adaptation ability. On an initial cohort of four NSCLC patients, the estimated tumor volume reductions ranged between 3–46% with a median of 8% by mid‐treatment and between 26–51% with a median of 34% by the end of treatment. Conclusion: We have demonstrated a new approach for tracking tumor regression during the course of radiotherapy treatment of NSCLC patients based on a novel level‐set segmentation algorithm. This approach provides us with a semi‐automated tool for quantifying tumor shrinkage and allows accurate estimates of ‘true’ accumulated dose to the tumor.Supported by CA85181 grant.
TH‐SAMS‐332‐01: Dosimetry and Common Pitfalls in the ACR CT Accreditation Program
Authors: Pfeiffer D 
Published: July 2008

Facilities participating in the American College of Radiology Computed Tomography Accreditation Program require significant support from Medical Physicists. A number of presentations in prior years have covered the mechanics of preparing a submission to the program. Recently, changes and clarification were made to the program. Rather than covering the basics of scanning the phantom, this presentation will focus on these recent changes and some common pitfalls and how to avoid them. Issues around dosimetry measurements will be covered. Finally, areas where Medical Physicists can provide additional support to facilities will be briefly discussed.Educational Objectives:1. To become aware of the new dose limits of the ACR CT Accreditation Program.2. To gain an understanding of some of the common application pitfalls and how to avoid them.3. To gain insight regarding the role of the Medical Physicist within a clinical CT program.
TH‐SAMS‐332‐03: Design and Performance Evaluation of Cone Beam CT Systems : Cone Beam Angio CT
Authors: Fahrig R 
Published: July 2008

Conebeam CT using C‐arm mounted large area flat panels (FPs) is becoming more commonly used in neuro‐ and body‐interventional suites. The ability to visualize vascular geometry in 3D along with soft tissue during an intervention is providing information that may increase accuracy, shorten procedure time and may even change the course of treatment. However, acquisition of the projection data required for volume imaging requires dose to the patient, and understanding the trade‐offs between acquisition parameters, dose and image quality is critical to the appropriate adoption of this imaging technique.Unlike conventional CT, the beam length in conebeam CT can cover the entire length of the object to be imaged or can be varied with the use of collimation, and the concept of CTDI is not, therefore, the metric of choice for measurement of dose. In addition, most C‐arm conebeam CT systems use a short‐scan (pi plus fan‐angle) acquisition, and the dose distribution within the object is not cylindrically symmetric. Finally, since FP design has been optimized for fluoroscopy, image quality when used for CT must be carefully evaluated.This lecture will describe a dose metric that is appropriate for conebeam CT and allows direct comparison with the CTDIw of conventional CT. A perception study using the CATPHAN 600 phantom for a range of acquisition parameters will be described, and the relationships between kVp, image noise, dose and contrast perception will be discussed.Research sponsored by Siemens Medical Solutions AG, AX Division, by NIH grant R01 EB003524 and by the Lucas Foundation.Educational Objectives:1. Understand how differences in acquisition geometry between conebeam and conventional CT affect dose distribution and dose measurement.2. Understand how contrast perception in conebeam CT images depends on acquisition parameters.
TH‐A‐342‐01: ACR MR Accreditation Update: The Role of the Medical Physicist
Authors: Price R 
Published: July 2008

In 2006, the ACR council approved a resolution requiring the current ACR MRI Accreditation Program to be redesigned into a modular program. The current program is limited to only whole‐body and cardiac accreditation. The new modular program will offer six clinical modules and is designed to allow a facility to have an accreditation that is more appropriately matched to the individual practice and the patient population being served. The six modules are: body, head, MR angiography (MRA), spine, musculoskeletal and cardiac. A breast MR accreditation program is currently under development; however, will not be one of these MR modules. Instead, it will be part of the Breast Imaging Accreditation Program. Also, an accreditation program specifically designed for special‐purpose orthopedic systems is under development.This continuing education course will review the current status and requirements of the ACR Whole Body MRI Accreditation Program, anticipated changes related to the proposed modular program and anticipated changes in the MRI Quality Control Manual as related to the Annual Medical Physicist Performance Survey.Educational Objectives:1. Review the role of the Medical Physicist in the current Whole Body Accreditation Program with emphasis on the requirements of the annual performance survey.2. Discuss the status of the proposed ACR modular accreditation program as well as the new initiatives into cardiac and orthopedic accreditation and the anticipated impact that these changes will have on the role of the medical physicist.3. Discuss special accreditation considerations related to 3T systems and for systems with parallel imaging capability.
TH‐B‐AUD C‐01: Functional Imaging for Therapy
Authors: Cao Y 
Published: July 2008

The clinical value of in vivo functional and physiological imaging (perfusion, diffusion, and diffusion tensor imaging) for assessment of therapeutic responses has been demonstrated in recent years. In vivo functional and physiological imaging can provide early prediction for treatment outcomes and organ and tissue complications, compared to conventional clinical methods and anatomic imaging. The advantage of early assessment is to allow for re‐optimizing individual patients' treatment plans, including decisions of total dose, modifying risks of critical normal tissue, and optimizing use of concomitant therapies. Clinical applications of perfusion, permeability, diffusion and diffusion tensor imaging are increasing rapidly.This lecture will provide an overview of physiological origins of perfusion, permeability, diffusion and diffusion tensor imaging, as well as clinical applications, typical imaging acquisition protocols, and image processing methods. The limitations of these techniques will also be discussed.Educational Objectives:1. Understand the physiological origins of perfusion, diffusion and diffusion tensor imaging.2. Understand typical imaging acquisition protocols and basic image processing methods.3. Understand clinical applications and limitations.