| Accuracy of EGSnrc calculations at 60Co energies for the response of ion chambers configured with various wall materials and cavity dimensions. | |
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MedLine Citation:
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PMID: 19175120 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In this investigation, five experimental data sets are used to evaluate the ability of the EGSnrc Monte Carlo code to calculate the change in chamber response associated with changes in wall material and cavity dimension at 60Co energies. Calculations of the ratios of response per unit mass of air as a function of cavity volume for walls ranging from polystyrene to lead are generally within 1%-3% of experiments. A few exceptions, which are discussed, include 20%-30% discrepancies with experiments involving lead-walled chambers used by Attix et al. [J. Res. Natl. Bur. Stand. 60, 235-243 (1958)] and Cormack and Johns [Radiat. Res. 1, 133-157 (1954)], and 5% discrepancies for the graphite chamber of Attix et al. (relative to data for other wall materials). Simulations of the experiment by Whyte [Radiat. Res. 6, 371-379 (1957)], which varied cavity air pressure in a large cylindrical chamber, are generally within 0.5% (wall/electrode materials ranging from beryllium to copper). In all cases, the agreement between measurements and EGSnrc calculations is much better when the response as a function of cavity height or air pressure is considered for each wall material individually. High-precision measurements [Burns et al., Phys. Med. Biol. 52, 7125-7135 (2007)] of the response per unit mass as a function of cavity height for a graphite chamber are also accurately reproduced, and validate previous tests of the transport mechanics of EGSnrc. Based on the general agreement found in this work between corresponding experimental results and EGSnrc calculations it can be concluded that EGSnrc can reliably be used to calculate changes in response with changes in various wall materials and cavity dimensions at 60Co energies within a accuracy of a few percent or less. |
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Authors:
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Daniel J La Russa; D W O Rogers |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Medical physics Volume: 35 ISSN: 0094-2405 ISO Abbreviation: Med Phys Publication Date: 2008 Dec |
Date Detail:
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Created Date: 2009-01-29 Completed Date: 2009-02-20 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0425746 Medline TA: Med Phys Country: United States |
Other Details:
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Languages: eng Pagination: 5629-40 Citation Subset: IM |
Affiliation:
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Carleton Laboratory for Radiotherapy Physics, Ottawa Carleton Institute of Physics, Ottawa, Ontario, Canada. dlarussa@physics.carleton.ca |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Algorithms Cobalt Radioisotopes / diagnostic use* Equipment Design Graphite Ions Kinetics Materials Testing Models, Statistical Polystyrenes Radiation Dosage Radiotherapy Dosage Radiotherapy Planning, Computer-Assisted / instrumentation, methods Reproducibility of Results Scattering, Radiation |
| Chemical | |
Reg. No./Substance:
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0/Cobalt Radioisotopes; 0/Ions; 0/Polystyrenes; 7782-42-5/Graphite |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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