Feasibility study of volumetric modulated arc therapy with constant dose rate for endometrial cancer

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• 作者：Ruijie Yang ; Junjie Wang ; Feng Xu ; Hua Li ; Xile Zhang
• 关键词：Volumetric modulated arc therapy ; Constant dose rate ; Intensity-modulated radiation therapy ; Endometrial cancer
• 刊名：Medical Dosimetry
• 出版年：2013
• 出版时间：Autumn, 2013
• 年：2013
• 卷：38
• 期：3
• 页码：351-355
• 全文大小：2466 K

文摘

To investigate the feasibility, efficiency, and delivery accuracy of volumetric modulated arc therapy with constant dose rate (VMAT-CDR) for whole-pelvic radiotherapy (WPRT) of endometrial cancer. The nine-field intensity-modulated radiotherapy (IMRT), VMAT with variable dose-rate (VMAT-VDR), and VMAT-CDR plans were created for 9 patients with endometrial cancer undergoing WPRT. The dose distribution of planning target volume (PTV), organs at risk (OARs), and normal tissue (NT) were compared. The monitor units (MUs) and treatment delivery time were also evaluated. For each VMAT-CDR plan, a dry run was performed to assess the dosimetric accuracy with MatriXX from IBA. Compared with IMRT, the VMAT-CDR plans delivered a slightly greater V₂₀ of the bowel, bladder, pelvis bone, and NT, but significantly decreased the dose to the high-dose region of the rectum and pelvis bone. The MUs decreased from 1105 with IMRT to 628 with VMAT-CDR. The delivery time also decreased from 9.5 to 3.2 minutes. The average gamma pass rate was 95.6 % at the 3 % /3 mm criteria with MatriXX pretreatment verification for 9 patients. VMAT-CDR can achieve comparable plan quality with significant shorter delivery time and smaller number of MUs compared with IMRT for patients with endometrial cancer undergoing WPRT. It can be accurately delivered and be an alternative to IMRT on the linear accelerator without VDR capability.