Dosimetric study on coplanar unequal 5-field versus jaw tracking intensity-modulated radiotherapy for middle thoracic esophageal cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第7期
- Page:
- 810-815
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric study on coplanar unequal 5-field versus jaw tracking intensity-modulated radiotherapy for middle thoracic esophageal cancer
- Author(s):
- YANG Han; ZHONG Mingsong; WU Furong; LI Qicheng; JIN Fu
- Chongqing University Cancer Hospital/Chongqing Cancer Institute/Department of Radiation Oncology, Chongqing Cancer Hospital, Chongqing 400030, China
- Keywords:
- Keywords: esophageal cancer jaw tracking static jaw intensity-modulated radiotherapy dosimetry
- PACS:
- R735.1；R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.07.003
- Abstract:
- Abstract: Objective To compare the dosimetric different of 4 different intensity-modulated radiotherapy (IMRT) plans, and to explore the dosimetric effects of different field arrangements and jaw tracking (JT) technique on target areas and organs-at-risk in radiotherapy for middle thoracic esophageal cancer. Methods Ten patients with squamous cell carcinoma were enrolled in the study. Four kinds of radiotherapy plans, including 3 static jaw plans and 1 JT plan, were designed for each patient. The static jaw plans included IMRT1 (0°, 130°, 160°, 195°, 220°), IMRT2 (0°, 130°, 165°, 200°, 330°) and IMRT3 (0°、30°、130°、200°、330°), and there was only 1 JT plan (IMRT-JT) in which the dose was recalculated and assessed by JT technique based on IMRT2. The dose-volume parameters of target areas and organs-at-risk, conformity index (CI), homogeneity index (HI) and monitor units (MU) were compared among 4 different plans. Results The target dose distribution in 4 plans all met the prescribed dose requirements. The comparison among IMRT1, IMRT2 and IMRT3 showed that the CI of PTV in IMRT1 and IMRT3 was slightly higher than that in IMRT2, and that the V20, V30, V40 and Dmean of the heart were highest in IMRT3, followed by IMRT2 and IMRT1 (P<0.05), and that the Dmax and D1% of spinal cord were highest in IMRT2, followed by IMRT3 and IMRT1 (P<0.05), and that compared with the other two plans, IMRT2 plan significantly reduced the V5, V20 and Dmean of lungs, but increased MU (P<0.05). There was no statistically significant difference in the HI of PTV between IMRT2 and IMRT-JT, but the CI of IMRT-JT was higher than that in IMRT2 (P<0.05). IMRT-JT was superior to IMRT2 in decreasing the dosimetric parameters of lungs (V5, V20, V30, Dmean), the heart (V20, V30, V40, Dmean), and spinal cord (Dmax, D1%, Dmean), but MU in IMRT-JT was increased as compared with that in IMRT2 (P<0.05). Conclusion Although IMRT1 and IMRT2 can decrease the doses to the heart and lungs, respectively, JT technique can further decrease the doses to organs-at-risk.
Last Update: 2020-07-28