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WE-C-AUD C-06: Comparing Deformable Composite Planning with Conventional Composite Planning

Medical Physics 2008年第6PART23期35卷 2936-2936页

作者： J Mikell G Starkschall Univ. of Texas MD Anderson Cancer Center Houston TX UT MD Anderson Cancer Center Houston TX

Purpose: A major concern when planning radiation treatments to previously irradiated patients is the possibility of overlap of radiation fields with those of previous treatments, so accurate dose mapping from previous... 详细信息

Purpose: A major concern when planning radiation treatments to previously irradiated patients is the possibility of overlap of radiation fields with those of previous treatments, so accurate dose mapping from previous plans is essential. Current composite planning does not account for anatomical variations between courses when mapping previous dose. The purpose of this work is to demonstrate proof of principle that treatment planning based on deformable image registration can be implemented on a commercial treatment planning system. (Pinnacle 3 , Philips Healthcare, Milpitas CA) Method and Materials: Three thoracic patients were selected from our institution using an IRB-approved retrospective chart review. Conventional and deformable composite plans were created for 2 patients whose courses were separated by 23 (Patient A) and 67 (Patient B) months. Conventional, deformable, and inverse deformable composite plans were created for the third patient (Patient C) who underwent re-planning 11 days after the initial planning during a single course of treatment. computer scripts were developed and run to merge course information and enable inverse planning on merged datasets with deformed dose distributions. Dose volume histograms (DVH) of the lungs, heart, spinal cord, and target volumes were created. Results: For Patients A and B respectively, 10% of the planning target volume for the deformed composite plan received more than 88Gy and 124Gy versus 70Gy and 94.6Gy for the conventional plan. For Patient C the gross tumor volume receiving 95% of the prescribed dose was 96.5%, 93.75%, and 99.54% for the conventional, deformed, and inverse deformed composite plans respectively. There was little change in DVHs of critical structures for all plans. Conclusion: Deformable composite planning has the potential to identify issues that are not seen in conventional composite planning. Furthermore, inverse deformable composite planning has the ability to increase target dose uniform

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SU-GG-T-394: Efficient Mass Deployment of ROIS Client computers

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Medical Physics 2008年第6PART15期35卷 2815-2815页

作者： DYJ Kim SUNY Upstate Medical University Syracuse NY

Purpose: To develop an efficient method of deploying 31 new client PCs obtained as part of a Radiation Oncology Information System (ROIS) upgrade. The major challenges were 1) reconciling the Windows domain environmen... 详细信息

Purpose: To develop an efficient method of deploying 31 new client PCs obtained as part of a Radiation Oncology Information System (ROIS) upgrade. The major challenges were 1) reconciling the Windows domain environment required by the ROIS, with the Novell environment required for institutional (hospital-wide) applications, 2) getting all departmental, institutional, and extra-institutional client applications to work properly under normal user privileges, and 3) the short weekend timeframe of the upgrade. Method and Materials: The 31 Dell GX755 clients were preinstalled with a standard setup from the hospital IT department, including Windows XP, Novell Client, and hospital-wide applications. Deployment of the clients during the ROIS upgrade occurred in 2 groups. In Group 1, Windows domain membership and ROIS client applications were manually installed at each client. For Group 2, a single model client received the Group 1 installation, followed by exhaustive client testing. After fixing the various non-ROIS client applications that were discovered to be incompatible with the ROIS setup, the “perfected” model client was cloned via Microsoft Sysprep and Knoppix Linux to the other Group 2 clients. Results: Group 1 clients were deployed during the ROIS upgrade weekend; however, nonfunctional hospital applications were subsequently discovered, requiring individual patching. Group 2 clients were deployed one week after the upgrade weekend, but all client software worked properly from the start. Conclusion: The Group 2 method of “perfect then clone” is the preferable solution for mass deployments as it automates numerous tasks that would otherwise require repeating on every client. Post-upgrade, this method is undoubtedly superior as it provides an optimal method for restoring a disabled client. However, it requires that all troubleshooting occur “up front” before cloning, which, with proper planning, support, and expertise, should be possible to accomplish within the tim

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TU-E-350-02: Medical Imaging Physics: Career Opportunities and Considerations

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Medical Physics 2008年第6PART22期35卷 2915-2915页

作者： G Barnes University Alabama Birmingham Birmingham AL

Medical imaging is big business — a multibillion dollar business, both for the manufacturers of medical imaging equipment and for health care providors. It plays an important role in diagnosis and in therapy. For the... 详细信息

Medical imaging is big business — a multibillion dollar business, both for the manufacturers of medical imaging equipment and for health care providors. It plays an important role in diagnosis and in therapy. For these and other reasons medical imaging physics offers a number of highly satisfying career paths — clinical support in small to moderate sized medical centers, consulting clinical support, academic radiology positions, and positions in industry. For the past 30+ years, the career path an individual takes depends primarily on individual interest and capabilities and to a lesser extent on job availability. This session focuses on the responsibilities of the medical imaging physicist in these different career paths. Presented are examples of different career paths. Discussed are the responsibilities that medical physicists typically have, minimum educational and experience requirements, and desirable skills and credentials. This Meet the Expert Session will be moderated by Gary T. Barnes, Ph.D. Dr. Barnes has worked for more than thirty-five years in medical imaging. His experience encompasses routine clinical support, radiology resident teaching, mentoring of young medical physicists, research, and prototype medical imaging equipment development. He is a Fellow of the AAPM, ACR and AIMBE, and is currently Professor Emeritus, Department of Radiology, UAB Medical Center, President of RAD Physics, Inc., a medical physics consulting company he founded in 1978, and President of X-Ray Imaging Innovations, a technology development company he founded in 1998. For the fifteen years prior to his retirement from UAB and becoming Professor Emeritus, he was the Director of the Physics and Engineering Division of the Department of Radiology. The Division included medical physics faculty, medical imaging equipment service engineers, QC technologists and technicians, computer programmers, and other informatics specialists. At the time of his retirement the Division had twen

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SU-GG-I-156: Potential Sources of Variation in Quantitative Ultrasound Quality Control Measurements

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Medical Physics 2008年第6PART5期35卷 2677-2677页

作者： R Marsh R Stafford D Reeve UT MD Anderson Cancer Center Houston TX

Purpose: The AAPM Ultrasound Task Group No. 1 has recommended various quality control (QC) tests for ultrasound systems, including quantitative measures of spatial resolution (via full width half maximum, or FWHM) and... 详细信息

Purpose: The AAPM Ultrasound Task Group No. 1 has recommended various quality control (QC) tests for ultrasound systems, including quantitative measures of spatial resolution (via full width half maximum, or FWHM) and depth of penetration (DOP) of the ultrasound beam. In our department, FWHM and DOP are measured using spatial measurement tools built into the ultrasound system software. However, the measurements are subjective, compounding variations in how each physicist makes the measurements with variations in the performance of the ultrasound system. Here, we seek to determine the role of these user-based measurement variations. Method and Materials: To remove user subjectivity, a Matlab program was written to automate the measurement of FWHM and DOP, requiring the user only to draw a cross-section through the filament target in the phantom (for FWHM) and define the edges of the images (for DOP). The automated software was used to analyze QC images for L12-5 ultrasound transducers (n=11) used with Philips iU22 scanners; analysis was performed by three physics technologists, all of whom have been trained to routinely perform ultrasound QC. Results were compared with historical measurements made by visual inspection. Results: The two measurement techniques yielded axial and lateral FWHM values that differed by an average of 18% and 15%, respectively. The manual measurements had a range of 0.56mm and 0.47mm, respectively, while the automated measurements had an average range of 0.28mm and 0.13mm. The automated DOP measurements differed from the manual measurements by an average of 3.9mm±5.9mm; there was little difference in the range of DOP values. Conclusion: While little improvement was seen in the measurement of DOP, images that did not meet the criteria set forth by TG1 for FWHM when measured manually passed using the automated technique. This highlights the importance of distinguishing between user- and equipment-dependent variations in QC measurements.

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MO‐A‐BRB‐01: Review of the AAPM TG‐105

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Medical Physics 2007年第6期34卷 2510-2511页

作者： Chetty, I.J. Rogers, Dwo Univ of Nebraska Med Center Omaha NE United States Carleton University Ottawa ON Canada

Despite its proven accuracy and the potential for improved dose distributions to influence treatment outcomes, the long calculation times previously associated with MC simulation rendered this method impractical for r... 详细信息

Despite its proven accuracy and the potential for improved dose distributions to influence treatment outcomes, the long calculation times previously associated with MC simulation rendered this method impractical for routine clinical treatment planning. However, the development of faster codes optimized for radiotherapy calculations and improvements in computer processor technology have substantially reduced calculation times to, in some instances, within minutes on a single processor. Several commercial vendors have released or are currently in the process of releasing MC algorithms for photon and/or electron beam treatment planning. Consequently, the accessibility and use of MC treatment planning algorithms may well become widespread in the radiotherapy community. With MC simulation, dose is computed stochastically using first principles;this method is therefore quite different from conventional dose algorithms. Issues such as statistical uncertainties, the use of variance reduction techniques, the ability to account for geometric details in the accelerator treatment head simulation, and other features, are all unique components of a MC treatment planning algorithm. Successful implementation by the clinical physicist of such a system will require an understanding of the basic principles of MC techniques. Educational Objectives: 1. To provide an educational review of the physics of the MC including discussion of methods used for coupled photon and electron transport. 2. To review the methods used to improve the simulation efficiency. 3. To briefly review the vendor transport codes currently used for clinical treatment planning. 4. To describe the development of treatment head models for clinical treatment planning. 5. To discuss the factors associated with MC dose calculation within the patient‐specific geometry, such as statistical uncertainties, CT‐to‐material, and reporting of dose‐to‐medium versus dose‐to‐water. 6. To discuss the issues associated with experimen

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Renormalization group approach to satisfiability

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EPL 2007年第3期77卷

作者： Coppersmith, S. N. Univ Wisconsin Dept Phys Madison WI 53706 USA

Satisfiability is a classic problem in computational complexity theory, in which one wishes to determine whether an assignment of values to a collection of Boolean variables exists in which all of a collection of clau... 详细信息

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Recommendation model based on opinion diffusion

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EPL 2007年第6期80卷

作者： Zhang, Y. -C. Medo, M. Ren, J. Zhou, T. Li, T. Yang, F. Univ Fribourg Dept Phys CH-1700 Fribourg Switzerland Renmin Univ China Dept Phys Beijing 100872 Peoples R China Univ Sci & Technol China Dept Modern Phys Hefei 230026 Peoples R China

Information overload in the modern society calls for highly efficient recommendation algorithms. In this letter we present a novel diffusion-based recommendation model, with users' ratings built into a transition ... 详细信息

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MO‐A‐M100F‐01: Integrating the Healthcare Enterprise (IHE) in Radiation Oncology: Will It Help You?

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Medical Physics 2007年第6期34卷 2511-2511页

作者： Curran, B. Univ Michigan Medical Center Ann Arbor MI United States

Initiated in 2005, Integrating the Healthcare Environment for Radiation Oncology (IHE‐RO) is a multi‐society, multi‐vendor effort to improve the safety, reliability, and integration of computer and information syst... 详细信息

Initiated in 2005, Integrating the Healthcare Environment for Radiation Oncology (IHE‐RO) is a multi‐society, multi‐vendor effort to improve the safety, reliability, and integration of computer and information systems within the radiation oncology arena. IHE‐RO works to accomplish this by coordinating the use of standards such as DICOM and HL7 to effectively exchange information between diverse computer systems involved in the process of planning and delivery of radiation therapy treatments. It attempts to remove ambiguity where it exists in these standards by defining consensus profiles to solve real‐world situations. Each IHE domain (radiology, cardiology, radiation oncology, …) identifies areas where improvements need to be made in the sharing / exchange of information between disparate systems. An IHE Planning Committee then defines a real‐world use case illustrating this process and a trial Integration Profile for improving it. This profile is then discussed by the Technical Committee, which defines the specific standards and methods for exchanging information that will be used to satisfy the needs of the profile and use case. Finally, the Integration Profile and detailed implementation specifics are published in the domain's Technical Frameworks documentation. Once published, those vendors participating in the IHE process develop / refine products to meet the Integration Profile's requirements. Testing occurs via test tools developed for the profiles and then demonstrated in a formal Connectathon, held under the auspices of the society sponsoring the domain. Companies that successfully demonstrate their compliance with the profile are then included in a public demonstration, held at the society's annual meeting. The complete process from profile initiation to public demonstration typically takes 20–24 months. In this session, the progress of the IHE‐RO effort will be reviewed. The profile selected for demonstration at the ASTRO 2007 Annual Meeting will be disc

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SU‐FF‐T‐410: The Influence of Scanner Parameters On the Accuracy of Film Dosimetry: A Comparison of the Epson Expression 1680 Flatbed and the Vidar VXR‐16 Dosimetry PRO Film Scanners

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Medical Physics 2007年第6期34卷 2496-2496页

作者： Wilcox, E. Daskalov, G. Nedialkova, L. St. Francis Hospital Hartford CT United States

Purpose: To investigate the properties of Vidar VXR‐16 Dosimetry PRO™ and Epson Expression 1680 film scanners with Gafchromic EBT and EDR2 radiographic films for dosimetry applications. Method and Materials: The EDR2... 详细信息

Purpose: To investigate the properties of Vidar VXR‐16 Dosimetry PRO™ and Epson Expression 1680 film scanners with Gafchromic EBT and EDR2 radiographic films for dosimetry applications. Method and Materials: The EDR2 and EBT films are irradiated with 10 × 10 cm² 6 MV X‐ray beams in solid water. Dose calibration curves are obtained using an MLC generated stepwedge. Each EDR2 or EBT film is scanned in both vertical and horizontal orientation with Vidar and Epson scanners in transmission mode and analyzed using FilmQA™ (3cognition LLC) software. The RIT (Radiological Imaging technology, Colorado Springs) software is used with the Vidar only. Epson scans are done without color correction in the 48‐bit RGB mode, resolution 75 dpi. The R channel image is used for analysis. Vidar scans are done with resolution 71 dpi, logarithmic and linear translation tables, and the 16‐bit grayscale image is analyzed. Results: For the EDR2 film no differences are observed for different scan orientations on either Epson or Vidar scanners with both RIT and FilmQA software. The EBT scans show no difference for different scan directions on either scanner. However, artifacts are associated with different translation tables with the Vidar while up to 2% differences are observed in the penumbra with Epson. Scanning measurement, calibration, and background films in the same direction estimates doses on central axis with 2% accuracy for both film types and scanners. However, inconsistent scan directions result in errors up to 10% on Epson and 41%‐45% on Vidar scanner. Conclusion: Calibration curve differences depend on the type of scanner, scanning mode, scanning software, and film orientation. The EDR2 on either scanner reproduces relative profiles and dose to better than 2% regardless of orientation. For the EBT the scanner parameters, orientation, and software corrections become important for accurate dosimetry results and to avoid artifacts. © 2007, American Association of Physicis

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TH‐D‐L100J‐06: Streaming Architectures for Cone‐Beam CT Image Reconstruction and Deformable Registration

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Medical Physics 2007年第6期34卷 2634-2634页

作者： Singh, H. Kandasamy, N. Folkert, M. Sharp, G. Drexel University Philadelphia PA United States Massachusetts General Hospital Boston MA United States

Purpose: To develop data‐parallel algorithms for tomographic reconstruction and deformable registration within a stream‐processing paradigm, and execute them on cheap stream processors such as graphics processing un... 详细信息

Purpose: To develop data‐parallel algorithms for tomographic reconstruction and deformable registration within a stream‐processing paradigm, and execute them on cheap stream processors such as graphics processing units (GPUs). Method and Materials: In the computer sciences, the stream‐processing paradigm is emerging as a cost‐effective way of solving large‐scale parallel computing problems. This is due to the recent introduction of high‐performance stream‐processing hardware such as the Cell processor and GPUs—both are commodity stream (or vector) processors, designed specifically to support large‐scale parallel computing on a single chip. This presentation describes how to use the stream‐processing model to significantly accelerate the complex problems of data reconstruction and fusion for radiotherapy. Highly data‐parallel models were developed for: (1) the Feldkamp, Davis, and Kress (FDK) reconstruction algorithm, and (2) Demon's algorithm for optical‐flow based deformable registration. These models were implemented within the Brook programming environment and executed on an nVIDIA 8800 GPU. Results: The performance of GPU‐based implementations of the FDK and Demon's algorithms was analyzed using data obtained from an IGRT testbed of a preserved swine lung. The results indicate a substantial speedup of up to 17 times for FDK, and up to 33 times for Demons, when compared with a 2.4 GHz Intel Duo‐Core processor. In addition, the GPU was found to be capable of high‐quality reconstructions, with differences within a few Hounsfield unit. Conclusions: Results indicate that data‐parallel image‐processing algorithms, when properly designed and executed on a GPU, achieve significant speedup when compared to high‐end desktop CPUs. The acceleration of key data‐processing stages will decrease the time needed to perform image‐guided patient positioning and analysis. © 2007, American Association of Physicists in Medicine. All rights reserved.

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