Application of fluence-smoothing technique of Eclipse system in intensity-modulated radiotherapy for head and neck tumors(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第10期
- Page:
- 1224-1229
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Application of fluence-smoothing technique of Eclipse system in intensity-modulated radiotherapy for head and neck tumors
- Author(s):
- JIA Xiaobin1; DONG Xiaoqing2; ZHU Hao3; DING Jiping1; YUAN Zhengxi1; YUE Kun1
- 1. Department of Radiotherapy, the Ninth Peoples Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 201900, China 2. Department of Radiotherapy, Tenth Peoples Hospital of Tongji University, Shanghai 200072, China 3. Clinical Application Department of Varian Medical Systems, Inc., Beijing 102600, China
- Keywords:
- Keywords: head and neck tumors fluence-smoothing technique intensity-modulated radiotherapy average leaf pair opening
- PACS:
- R815
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.10.003
- Abstract:
- Abstract: Objective To analyze and evaluate fluence-smoothing technique in the radiotherapy for head and neck tumors based on Edge system. Methods The clinical information of 40 postoperative patients with head and neck tumors were retrospectively analyzed, and 6 reverse intensity-modulated radiotherapy (IMRT) plans were designed for each patient with Eclipse v13.6 system. The 6 groups of plans included control group (Smooth 0, 0) which were optimized with the smoothing values of X, Y at 0, experimentalⅠgroup (Smooth 20, 20), experimental Ⅱ group (Smooth 40,40), experimental Ⅲ group (Smooth 60,60), experimental Ⅳ group (Smooth 80, 80) and experimental Ⅴ group (Smooth 100, 100). The dosimetric differences of target areas and organs-at-risk were evaluated among different groups, and the average leaf pair opening (ALPO), MU factor and gamma passing rate were also analyzed. Results Compared with the dosimetric parameters in control group, there were statistical differences in the HI and CI of PCTV60, the HI of PCTV54 and the V50 of larynx in experimental groups (P<0.05), the Dmax of spinal cord in experimental Ⅱ to Ⅴ groups (P<0.05), the Dmean of larynx in experimental Ⅳ and Ⅴ groups (P<0.05), the V30 of parotid-L in experimental Ⅲ and Ⅴ groups (P<0.05), the Dmean of parotid-L in experimental Ⅱ and Ⅳ groups (P<0.05), and the V30 and Dmean of parotid-R in experimental Ⅴ group (P<0.05). With the increase of smoothing values, the CI of PCTV60 showed an increasing and then decreasing trend (reaching the maximum in Smooth 40, 40 plan), while the HI of PCTV60 and PCTV54 presented a decreasing and then increasing trend (reaching the minimum in Smooth 40, 40 plan). MU factor also showed a decreasing (Smooth 0,0 to Smooth 60, 60) and then increasing tendency (Smooth 60,60 to Smooth 100, 100). Moreover, gamma passing rate, the V50 of larynx and ALPO were increased as the increase of smoothing values, while MU showed a decreasing tendency. Conclusion Moderate fluence-smoothing reduces the complexity of plan delivery, but excessive fluence-smoothing affects target coverage and increases the dose of OAR. Based on clinical demands and linac limitations, the smoothing values of X,Y should be set at 40.
Last Update: 2020-10-29