bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐E‐352‐01: Medical Physics Education of Diagnostic Radiology Residents
Authors: Rzeszotarski M , Heintz P , Sprawls P 
Published: July 2008

This session provides a forum for discussion of the progress made in improving diagnostic radiology resident education and some of the opportunities in education becoming available due to new technologies available to the teacher and student.The first speaker will discuss the status of the curriculum for medical physics education of residents. At RSNA in November 2007, the AAPM medical physics resident curriculum committee met to review the first draft of new learning objectives which are being written for each section of the curriculum. The learning objectives are defined in three areas: 1) Fundamental Knowledge; 2) Clinical Application; and 3) Clinical Problem Solving. Radiologists and physicists are working together to develop these with a strong emphasis on clinical relevance.The second speaker will describe the efforts of a task force formed under the leadership of William Hendee, Ph.D. (AAPM) and George Bissett, M.D. (RSNA) to develop free web‐based educational modules for radiologic science (medical physics) education of residents. Two modules have been developed: one on CT dose and a second on interventional radiology dose and safety. RSNA has agreed to host these modules on their web site and will make them available free of charge to any AAPM (physicists) or RSNA members (radiologists and residents). Most important, both AAPM and RSNA have contributed substantial funds to encourage the development of these education modules. Authors will receive $3,000–$4,000 for the development of each module. Approximately 50 modules are planned. A Request for Proposals has been distributed requesting authors to contribute modules. Each physics module must be authored by a physicist and a radiologist and must follow specific guidelines regarding content, objectives, required post test and the use of clinical materials in the educational process. These modules will be useful for both residents in training and radiologists in clinical practice through their maintenance of certification process.The third speaker will provide a keynote lecture on “Evolving Models of Medical Image Physics and Technology Education.” See his abstract description for further details.
WE‐E‐351‐02: The Fusion of Molecular Imaging Into Clinical Medicine: A Role for AAPM?
Authors: Fullerton G 
Published: July 2008

The accelerating introduction of molecular imaging into medicine holds promise for cures of numerous intractable diseases. In vivo measurements of pathologic details at the molecular level are on the horizon but substantial work on improved precision and accuracy are necessary before methods can be clinically useful. Accurate knowledge of spatial and temporal dimensions of molecular measures is necessary before such measures can be validated as biomarkers of clinically significant endpoints. These are functions that AAPM members have performed over and over again in medicine over the five decade history of the association. The extension into molecular imaging, however, requires even broader participation in multi‐disciplinary teams extending beyond traditional departmental boundaries of radiology and radiation oncology. This presentation reviews developments in molecular imaging and the growing need to fuse molecular events to the spatial framework of well known anatomical imaging methods. The process of translation requires participation in preclinical studies using animal models to validate methods in experimentally controllable environments. The AAPM can play an important role in this process at numerous levels. Members can participate in the design and testing of new instrumentation for both preclinical/animal and human uses. Members can also use well documented society methods for developing nationally acceptable imaging standards and procedures for assuring the quality of data. This is especially important when data is intended for the use of regulatory agencies such as the FDA to prove the safety and efficacy of new methods of medical care.Educational Objectives:1. Understanding the meaning of “molecular imaging”2. Understanding the process for fusing molecular imaging into clinical medicine.3. Understand the potential role for medical physics in applying molecular imaging.
TH‐SAMS‐AUD B‐02: Image Fusion for Target Definition
Authors: Ulin K 
Published: July 2008

Imaging studies acquired at multiple times and using different modalities are important components to many clinical trials. Imaging is used for staging and protocol eligibility, for radiation therapy target definition, for adaptive radiation treatment delivery, for assessing response to therapy, and for outcome analysis. Currently co‐registration of CT, MR and PET scans may be important for any of these purposes; in the future, molecular and biomarker imaging may be incorporated.The challenges for the QA centers are to verify that institutions participating in protocols requiring image registration have the tools and expertise to perform the registrations, and to verify the appropriate registration for individual protocol patients. There are many software systems, many with multiple methods, available for image registration.One method to credential institutions is by benchmarking. QARC's “image fusion” benchmark requires the institution to download a DICOM MR and a DICOM CT scan set. The datasets are to be registered, the small lesion is to be outlined on the MR scan, and the geometrical center of the lesion on the CT scan is to be reported (lesion not visible on CT). Results from more than 50 institutions will be discussed.An increasing number of protocols require PET imaging. Registration of PET imaging is problematic, except for PET/CT. Since the DICOM standard does not include specifications for SUV calculations, currently only ACRIN, by using the manufacturers' workstations, is able to receive PET images and recalculate SUVs. Ideally these PET images would be registered with the planning CT in radiotherapy protocols.More and more protocols propose requiring IGRT, particularly for treatments with few fractions. For protocol participation, institutions need to demonstrate the reproducibility and accuracy of the imaging system used to adapt the daily treatment to the daily target position. Extensive questionnaires (QARC) and submission of representative patient data (RTOG) are required by the QA centers. The variety of systems — MV CT, kV CT, Tomotherapy, Cyberknife, ultrasound — provide a challenge for the QA center.An even greater challenge is how to provide QA for individual patient treatments. If CT/CT or CT/MR registration is used for target delineation, assessment of the registration presents the QA center with several questions. Should the QA center redo the registration? What tools can be developed to register and verify CT/PET registration? For adaptive radiotherapy, what is the benefit of reviewing the daily assessment of required repositioning? Is the benefit worth the cost of such an effort?Educational Objectives:1. Understand the issues faced by the QA centers in reviewing image registrations.2. Understand the difference between credentialing and providing individual patient QA for image registration.3. Become familiar with the current strategies of QA for image registration by the QA centers.
TH‐SAMS‐332‐02: ACR CT Accreditation Overview
Authors: Hernandez D 
Published: July 2008

The American College of Radiology CT accreditation program was launched in 2002. It has approximately 3320 active units and is growing daily.All sites that apply for CT accreditation receive a testing packet with the necessary paperwork and labels required for their testing material submission. CT accreditation involves the submission of clinical and phantom images. Qualified radiologists and medical physicists review all submissions.The medical physicist plays a vital role in the achievement of ACR accreditation. A team approach involving the supervising physician, lead technologist and medical physicist is necessary to ensure that all information is accurate and appropriate for ACR accreditation submission.For sites with filming capability, the phantom testing images are submitted on hard copy film. As more and more sites become film‐less, the need for electronic submission of phantom testing material has increased. Sites that have no filming capability can call the ACR and receive permission and instructions for submitting the CT phantom images electronically. Electronic phantom submission is currently a pilot program as the ACR actively works to define the process.Educational Objectives:1. Understand the basic materials and process of ACR CT accreditation.2. Understand the importance of a “team approach” in achievement of ACR accreditation.3. Understand the process of electronic submission of the CT phantom images.
TH‐B‐352‐01: Current IHE Topics: Mammography Display and CD Export
Authors: Flynn M , Peck D 
Published: July 2008

As a collaboration of professional societies and companies, Integrating the Healthcare Enterprise (IHE, www.ihe.net) seeks to establish methods wherein health computer systems can communicate to achieve specific functional objectives. IHE profiles define the detailed requirements that systems must meet in order to achieve the objective. These requirements often involve DICOM and HL7 standards. Periodic industry test sessions (called Connectathons) are used to demonstrate the conformance of specific products. Health domains include Radiology and Radiation Oncology. AAPM along with RSNA, SNM, and SIIM are member organizations and about 100 companies also participate. We focus this year on two recent IHE efforts which impact diagnostic radiology.1.)Radiology: Mammography Image (MAMMO) Integration Profile. In the Radiology Technical Framework, the MAMMO profile specifies how DICOM full field mammography images are created, exchanged, and used.The detailed specifications are supplemented in the IHE Radiology: Mammography User's Handbook. This profile provides important requirements for department implementing a mammography PACS system with workstation interpretation. Of particular importance are display specifications regarding presentation size, CAD overlays, and presentation states.2.)Radiology: Portable Data for Imaging (PDI) Integration Profile. This profile specifies methods that allow patients and referring physicians to obtain and view diagnostic images and reports. It is not intended to provide archival solutions. Use in operating rooms is specifically delineated. The use of CD media is specified along with both web based viewing support and DICOM standard CD records that can be imported and/or viewed by DICOM devices. The profile has taken on recent importance due to chronic problems in surgical specialties resulting from the prevalent use of proprietary formats on exported CDs. A problem now considered by the AMA to be a patient safety issue.Educational Objectives:1. Understand from two examples how the IHE profiles impact diagnostic radiology PACS.2. Learn how recent mammography profiles can be used when specifying systems for digital mammography reading.3. Understand how to avoid problems when exchanging image data between institutions.
TH‐C‐350‐05: Performance of a Beam Tracking System for Treatment of Moving Targets with Scanned Ion Beams
Authors: Bert C , Saito N , Schmidt A , Chaudhri N , Schardt D , Rietzel E 
Published: July 2008

Purpose: Scanned ion beam therapy of intra‐fractionally moving targets requires motion mitigation to prevent deteriorations of the delivered doses due to interplay. A beam tracking system was developed and experiments with various detectors were performed to assess system performance. Method and Materials: Tracking of moving targets with scanned ion beams requires simultaneous lateral and longitudinal range adaptation of pencil beam positions. Lateral beam tracking is achieved directly with the beam scanning system. Longitudinal tracking is performed with a dedicated energy modulation system consisting of fast, motorized absorber wedges. In experiments with radiographic films, a range telescope, and an array of pin‐point ionization chambers in a water phantom, the precision of lateral, longitudinal, and 3D motion compensation was measured. Motion was induced laterally by a sliding table and longitudinally by ramp‐shaped absorbers. Motion detection was performed with a laser‐triangulation sensor. Experimental tracking data were compared to results of measurements with stationary detector systems. Films were analyzed with respect to geometrical shape as well as mean, minimum, and maximum response level within the target region. Ionization chamber data were analyzed for different volumes of the setup. Analysis of range telescope data focused on Bragg‐peak shapes and ranges. Results: Film analysis yielded conservation of geometrical shape and responses (mean±SD, minimum, maximum) of (0.276±0.010, 0.241, 0.288) and (0.275±0.007, 0.252, 0.284) for stationary irradiation and tracking respectively. Within the target volume, ionization chamber data with beam tracking deviated from stationary irradiation by 0.3 ± 1.5% with −2.7% minimum and 3.7% maximum deviation. The Bragg peak range for tracking deviated by less than 0.25 mm water‐equivalent from the stationary reference. Conclusion: The tracking system for scanned ion beams successfully restored dose distributions for moving targets by adapting individual Bragg peaks during irradiations in quasi real time.Research sponsored in part by Siemens Healthcare, Particle Therapy.
TH‐C‐350‐09: 4D Treatment Planning and Dosimetric Validation of Helical Tomotherapy Treatments of Moving Tumors
Authors: Goddu S , Noel C , Chaudhari S , Parikh P , Khullar D , Santanam L , Low D 
Published: July 2008

Purpose: The objectives of this study are to describe the 4D treatment planning process for moving targets and to evaluate the dosimetric consequences caused by target motion during tomotherapy delivery. Method and Materials: A lung cancer patient was CT scanned using our standard 4D‐CT protocols on Phillips brilliance 64 slice CT scanner. A maximum intensity projection CT dataset was used for treatment planning. Tumor motion trajectory and amplitude was determined from the inhale and exhale phases of the 4DCT. A three‐dimensional motion pattern was created by scaling the breathing form to an average magnitude of the target motion. The three‐dimensional trajectory was programmed into the Washington University 4D Phantom to simulate target motion. Eight EDR2 films were loaded into a phantom for dosimetric verification. Measurements were performed on a static phantom and then repeated on the oscillating phantom. Experiments were repeated for their reproducibility. Films were analyzed using Hi‐Art TPS. Results: To quantify the dose errors, gamma analysis was performed. In static phantom study, >97% of the points passed with a gamma criteria of 3% and 3mm. When the same criterion was applied for the oscillating phantom, 15–25% of the points failed. When the gamma threshold was increased to 8% and the gamma analysis window was tailored to be within the CTV, >98% of the points passed indicating that the dose errors are of the order of 5% for majority of the points. In order to find the maximum dose errors, the tolerance was increased until 100% of points passing the criteria. Conclusion: 4D treatment planning process for helical tomotherapy is discussed. Gamma analysis revealed that, the dose errors are of the order of 5% for majority of the points and the maximum dose error within the CTV was 11%.This work is supported in part by Tomotherapy Inc.
TH‐C‐AUD A‐04: Calibration of Image‐Guided Robotic System for Prostate Brachytherapy
Authors: Buzurovic I , Podder T , Hu Y , Yan K , Valicenti R , Dicker A , Yu Y 
Published: July 2008

Purpose: To perform calibration and evaluation of an image‐guided brachytherapy robotic system. Method and Materials: Brachytherapy robot calibration consists of three steps: mechanical robotic calibration, image calibration and overall system calibration. Mechanical calibration determines 1)system resolution, as the smallest incremental movement that the robot can physically perform, 2)repeatability as a measure of the ability of the robot to move back to the same position and orientation and 3)accuracy, as the robot's ability to precisely move to a desired position in 3D space. Imaging calibration for our system is the procedure where distance from ultrasound images is transformed to the metric distance in robot absolute coordinates. Overall system calibration is to determine the exact position of image stacks, calculated in absolute robotic system coordinates. These steps were performed using high‐resolution camera, specially‐designed phantom box for imaging calibration and CMM device for mechanical calibration. The system software allows mutual calibration between mechanical and imaging robotic modules. Mechanical calibration consists of DHV table definition for robotic system, matrix transformation, definition of composite matrices, direct kinematics solution, inverse kinematics solution, definition of robot initial position, calculation of position error, and error correction method. The robot errors gathered by position measurement are minimized by numerical optimization. Results: The calibrated precision of translation movements for the stylet and cannula are in the range of 0.03–0.08mm (depending on load); lateral and vertical movements for the gantry are 0.03mm; probe translation and rotation are 0.05mm and 0.03deg, respectively. The fiducial error for imaging is less than 0.1mm in x and y image coordinates. Conclusion: Overall robotic brachytherapy calibration plays a crucial role in accurate delivery. The calibrated precisions of the image‐guided brachytherapy robotic system are considered satisfactory for the given clinical application.Acknowledgement: Supported by NCI‐R01‐CA091763.
TH‐C‐AUD A‐05: Experimental Validation of An Iterative Forward Projection Matching Algorithm for Seeds Center Localization Using Conebeam‐CT X‐Ray Projections
Authors: Pokhrel D , Murphy M , Todor D , Williamson J 
Published: July 2008

Purpose: To experimentally validate a new algorithm for reconstructing the 3D positions of implanted brachytherapy seeds from 2D projection images. Method and materials: The iterative forward projection matching (IFPM) algorithm consists of finding the 3D seed geometry that minimizes the sum‐of‐squared‐difference of the pixel‐by‐pixel intensities between computed projection images and measured auto‐segmented images of implanted seeds. IFPM starts with an approximation to the initial seeds configuration, e.g., the pre‐implant seed arrangement. It then iteratively refines the 3D seed coordinates until the computed projections match with the measured projections. Three pairs of computed and measured projection images, with known imaging geometry, are used. Two brachytherapy phantoms were fabricated with 12 and 72 seeds in known configurations. Three projections of each phantom were acquired using an Acuity digital simulator along with a full 660 projection Conebeam CT (CBCT). Image pre‐processing steps were performed to create the binary seed centroids images for use by IFPM algorithm. To quantify IFPM accuracy, the actual seed positions were extracted from the CBCT images by the Brachy Vision‐planning system. Results: For the 12 seed phantom data, the mean reconstruction error was found to be 0.83±0.34mm where as for 72 seed phantom it was 0.97±0.37mm. The each test trials converged in 4–10 iterations with computation time of 2.8–62 min on a 2 GHz processor. Discussion: The IFPM algorithm avoids establishing seed projection correspondence required by standard back‐projection methods. In phantom studies we have demonstrated 1 mm accuracy in reconstructing the 3D positions of brachytherapy seeds from 2D projection images. This supports the potential of this algorithm for accurate and robust seed reconstruction in patients.This project was supported by grant from Varian Medical Systems.
TH‐C‐351‐01: Design of the Washington University Small Animal Conformal Micro Irradiator
Authors: Izaguirre EW , Diao X , Stojadinovic S , Mutic S , Khullar D , Deasy J , Parikh P , Hope A , Grigsby P , Low DA 
Published: July 2008

Purpose: To design a conformal small animal micro radiation therapy (microRT) instrument, consisting of a cone beam microCT subsystem for submillimeter low dose structural imaging and image guided radiotherapy and an orthovoltage conformal micro irradiator with high radiation dose rate for high throughput conformal irradiation. Method and Materials: The microCT subsystem is based on an 80kVp micro‐focus x‐ray source with 75×75 um2 focal spot and a flat panel amorphous silicon detector with 1024×1024 pixels. The microRT subsystem design utilizes a 320kVp orthovoltage source with dual focus spots (0.4×0.4 mm2 at 800W and 1×1 mm2 at 1800 W). The orthovoltage beam is collimated using two orthogonal jaws and exchangeable apertures. The resolution of the cone‐beam micro CT and the therapy beam spatial precision was determined using a numerical model. The microCT radiation dose, the orthovoltage source spectral output, and dose rate were evaluated using a mouse digital phantom (MOBY) and a pencil beam algorithm. Results: microCT reconstructed tomographic data with a resolution of 125 μm is achievable using 128 projections and a maximum radiation dose of 2cGy. Automatic animal positioning and handling is performed within a precision of 100 μm. The treatment beam can be aimed at different latitude and longitude angles in steps of 2 arc min. and translated at 50μm steps (x,y,z). The beam cross section can be modulated with submillimeter precision using steps of 50μm. A radiation dose rate of 40 Gy/min is delivered when the system is operated at an average half‐value layer of 4.6 mm Cu and a maximum beam penumbra of 0.35 mm. Conclusion: We designed and numerically evaluated the performance of a microRT system integrated with a microCT for conformal radiotherapy of murine animal models.This work supported in part by NIH grant CA108677.