Dosimetric analysis of intensity-modulated arc radiotherapy with fixed dose rate versus volumetric modulated arc therapy for lung cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2018年第2期
- Page:
- 176-182
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric analysis of intensity-modulated arc radiotherapy with fixed dose rate versus volumetric modulated arc therapy for lung cancer
- Author(s):
- LONG Yusong; TAN Junwen; HE Xiantao; LIANG Weixue; WANG Zhanyu; LI Gang; FENG Yongfu
- Department of Oncology, the Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou 545005, China
- Keywords:
- ; Keywords: lung cancer; volumetric modulated arc therapy; intensity-modulated arc radiotherapy; fixed dose rate
- PACS:
- R815.6
- DOI:
- DOI:10.3969/j.issn.1005-202X.2018.02.011
- Abstract:
- Objective To analyze the dosimetric differences between intensity-modulated arc radiotherapy (IMAT) with fix dose rate and volumetric modulated arc radiotherapy (VMAT) for lung cancer, and provide reference for the selection of dose rate mode of VMAT for lung cancer. Methods IMAT and VMAT plans were designed for 11 patients with lung cancer using RayStation treatment planning system, and the differences in dosimetric parameters, monitor unit and delivery time were compared. Results Both dual arc IMAT and VMAT plans for lung cancer in 11 patients met the clinical requirements, and no significant differences were found in the minimum dose D98%, the maximum dose D2%, the average dose Dmean, homogeneity index and conformal index of target areas. However, the target coverage rate of VMAT plan was better than that of IMAT plan. The V5, V10, V20, Dmean of whole lung and the V20 of heart in VMAT were lower than those in IMAT plan, and the differences in the V30 of whole lung, the V30 of heart and the D1% of spine between IMAT and VMAT plans were not obvious. Compared with IMAT plan, VMAT plan had lower V5, V10 and V15 of normal tissues in the low-dose area, and normal tissues-Dmean, but higher V30, V35, V40 of normal tissues; two plans had no significant differences in the V20 and V25 of normal tissues. The delivery time of VMAT plan was greatly reduced, only 62% of that of IMAT plan. Two plans had similar monitor unit, without statistical differences. Though the dose passing rate of VMAT plan was slightly lower than that of IMAT plan, with a difference of about 0.44%, both the dose passing rates of the two plans were more than 98.72%, meeting treatment requirements. Conclusion Compared with IMAT, VMAT for lung cancer has a stronger plan modulation ability, can obtain better target dose distribution, improve the efficiency of treatment, and protect the organs-at-risk better, especially reducing the low-dose irradiation volume of lung. VMAT can bring more benefits to patients with lung cancer.
Last Update: 2018-01-29