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Author Ma, Lijun ♦ Mason, Erica ♦ Sneed, Penny K. ♦ McDermott, Michael ♦ Polishchuk, Alexei ♦ Larson, David A. ♦ Sahgal, Arjun
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword RADIOLOGY AND NUCLEAR MEDICINE ♦ BEAMS ♦ COMPARATIVE EVALUATIONS ♦ DELIVERY ♦ GEOMETRY ♦ MATERIALS ♦ MODULATION ♦ PLANNING ♦ RADIATION DOSES ♦ RADIOTHERAPY ♦ SURGERY
Abstract Purpose: To demonstrate the clinical feasibility and potential benefits of sector beam intensity modulation (SBIM) specific to Gamma Knife stereotactic radiosurgery (GKSRS). Methods and Materials: SBIM is based on modulating the confocal beam intensities from individual sectors surrounding an isocenter in a nearly 2π geometry. This is in contrast to conventional GKSRS delivery, in which the beam intensities from each sector are restricted to be either 0% or 100% and must be identical for any given isocenter. We developed a SBIM solution based on available clinical planning tools, and we tested it on a cohort of 12 clinical cases as a proof of concept study. The SBIM treatment plans were compared with the original clinically delivered treatment plans to determine dosimetric differences. The goal was to investigate whether SBIM would improve the dose conformity for these treatment plans without prohibitively lengthening the treatment time. Results: A SBIM technique was developed. On average, SBIM improved the Paddick conformity index (PCI) versus the clinically delivered plans (clinical plan PCI = 0.68 ± 0.11 vs SBIM plan PCI = 0.74 ± 0.10, P=.002; 2-tailed paired t test). The SBIM plans also resulted in nearly identical target volume coverage (mean, 97 ± 2%), total beam-on times (clinical plan 58.4 ± 38.9 minutes vs SBIM 63.5 ± 44.7 minutes, P=.057), and gradient indices (clinical plan 3.03 ± 0.27 vs SBIM 3.06 ± 0.29, P=.44) versus the original clinical plans. Conclusion: The SBIM method is clinically feasible with potential dosimetric gains when compared with conventional GKSRS.
ISSN 03603016
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-03-01
Publisher Place United States
Journal International Journal of Radiation Oncology, Biology and Physics
Volume Number 91
Issue Number 3


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