Dosimetric verification of volumetric modulated arc therapy for middle thoracic esophageal carcinoma(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第1期
- Page:
- 33-36
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric verification of volumetric modulated arc therapy for middle thoracic esophageal carcinoma
- Author(s):
- LI Liang; XIE Xin; FAN Xuemei; XU Yumei; ZHANG Longzhen; XIN Yong
- Department of Radiation Oncology, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China
- Keywords:
- ; Keywords: middle thoracic esophageal carcinoma; volumetric modulated arc therapy; dosimetric verification; setup error
- PACS:
- R811.1；R735.4
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.01.007
- Abstract:
- Abstract: Objective To investigate the methods for dosimetric and location verifications in volumetric modulated arc therapy (VMAT) for middle thoracic esophageal carcinoma. Methods Varian Eclipse 10.0 treatment planning system was used to design VMAT plans for 10 patients with middle thoracic esophageal carcinoma who were randomly enrolled in this study. The doses were measured with IBA Compass 3.0 dose verification system and then compared with the data from treatment planning system (TPS). The differences in the doses and volumes of target areas (planning target volume, clinical target volume and gross tumor volume) and organs-at-risk were analyzed, and the gamma passing rates were calculated. Cone beam computed tomography (CBCT) scan was performed once a week for 6 weeks in total. Finally, the setup errors were obtained by the registration between CBCT images and positioning images. Results With the standard of 3 mm/3%, the gamma passing rates of target areas and organs-at-risk were higher than 95%. The differences between measured values of the D95% and Dmean in target areas and data from TPS were less than 2%. For the V20 and V30 of lungs, TPS data were lower than the measured values, and the difference was within 1.65%. For the Dmax of spinal cord and the V30, V40 of heart, the differences between measured values and data from TPS were 2.23% and less than 2%, respectively. Setup error analysis showed that the number of cases with error >3 mm in anterior-posterior and left-right directions was more than that of cases with error >3 mm in head-foot direction. Conclusion Compass 3.0 dose verification system and CBCT scan are necessary to ensure the safety and reliability of VMAT to treat patients with middle thoracic esophageal carcinoma.
Last Update: 2019-01-24