| Relative biological damage and electron fluence in and out of a 6 MV photon field. | |
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MedLine Citation:
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PMID: 19826205 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Scattered radiation in the penumbra of a megavoltage radiation therapy beam can deposit a non-negligible dose in the healthy tissue around a target volume. The lower energy of the radiation in this region suggests that its biological effectiveness might not be the same as that of the open beam. In this work, we determined the relative biological damage in normal human fibroblasts after megavoltage irradiation in two geometries. The first was an open-beam irradiation and the second was a blocked configuration in which only scattered radiation could reach the target cells. The biological damage was evaluated by the gamma-H2AX immunofluorescence assay, which is capable of detecting DNA double-strand breaks in individual cells. We report that the scattered radiation is more effective at producing biological damage than the open beam radiation. We found a 27% enhancement in the net mean nuclear gamma-H2AX fluorescence intensity at 2 Gy and a 48% enhancement at 4 Gy. These findings are of interest due to the increased doses of penumbral radiation close to target volumes both in dose escalation studies and in IMRT treatment deliveries where high dose gradients exist for the purpose of conformal avoidance of healthy tissues. |
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Authors:
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A Syme; C Kirkby; R Mirzayans; M MacKenzie; C Field; B G Fallone |
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Publication Detail:
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Type: Journal Article Date: 2009-10-14 |
Journal Detail:
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Title: Physics in medicine and biology Volume: 54 ISSN: 1361-6560 ISO Abbreviation: Phys Med Biol Publication Date: 2009 Nov |
Date Detail:
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Created Date: 2009-10-20 Completed Date: 2010-02-18 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0401220 Medline TA: Phys Med Biol Country: England |
Other Details:
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Languages: eng Pagination: 6623-33 Citation Subset: IM |
Affiliation:
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Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Cell Nucleus
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metabolism Dose-Response Relationship, Radiation Electrons Fibroblasts / radiation effects* Histones / metabolism Humans Image Processing, Computer-Assisted Microscopy, Fluorescence / methods Models, Statistical Monte Carlo Method Photons* Radiotherapy Dosage Radiotherapy Planning, Computer-Assisted Radiotherapy, Intensity-Modulated Scattering, Radiation |
| Chemical | |
Reg. No./Substance:
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0/H2AFX protein, human; 0/Histones |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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