| Comparison of IMRT planning with two-step and one-step optimization: a strategy for improving therapeutic gain and reducing the integral dose. | |
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MedLine Citation:
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PMID: 19920309 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The aim of this study was to evaluate the effectiveness and efficiency in inverse IMRT planning of one-step optimization with the step-and-shoot (SS) technique as compared to traditional two-step optimization using the sliding windows (SW) technique. The Pinnacle IMRT TPS allows both one-step and two-step approaches. The same beam setup for five head-and-neck tumor patients and dose-volume constraints were applied for all optimization methods. Two-step plans were produced converting the ideal fluence with or without a smoothing filter into the SW sequence. One-step plans, based on direct machine parameter optimization (DMPO), had the maximum number of segments per beam set at 8, 10, 12, producing a directly deliverable sequence. Moreover, the plans were generated whether a split-beam was used or not. Total monitor units (MUs), overall treatment time, cost function and dose-volume histograms (DVHs) were estimated for each plan. PTV conformality and homogeneity indexes and normal tissue complication probability (NTCP) that are the basis for improving therapeutic gain, as well as non-tumor integral dose (NTID), were evaluated. A two-sided t-test was used to compare quantitative variables. All plans showed similar target coverage. Compared to two-step SW optimization, the DMPO-SS plans resulted in lower MUs (20%), NTID (4%) as well as NTCP values. Differences of about 15-20% in the treatment delivery time were registered. DMPO generates less complex plans with identical PTV coverage, providing lower NTCP and NTID, which is expected to reduce the risk of secondary cancer. It is an effective and efficient method and, if available, it should be favored over the two-step IMRT planning. |
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Authors:
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A Abate; M C Pressello; M Benassi; L Strigari |
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Publication Detail:
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Type: Comparative Study; Journal Article Date: 2009-11-17 |
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 Dec |
Date Detail:
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Created Date: 2009-11-20 Completed Date: 2010-02-19 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: 7183-98 Citation Subset: IM |
Affiliation:
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Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome, Italy. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Head and Neck Neoplasms
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radiotherapy Humans Probability Radiation Dosage* Radiotherapy Dosage Radiotherapy Planning, Computer-Assisted / methods* Radiotherapy, Intensity-Modulated / adverse effects, methods* Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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