Dosimetric effect of CT truncated regionson radiotherapy for thoracic esophageal cancer
10.13491/j.issn.1004-714X.2022.06.015
- VernacularTitle:CT截断区域对食管癌患者放疗计划剂量学影响
- Author:
Kai XIE
1
,
2
,
3
;
Heng ZHANG
3
;
Qianyi XI
3
;
Fan ZHANG
3
;
Sai ZHANG
3
;
Liugang GAO
1
,
2
,
3
;
Jiawei SUN
1
,
2
,
3
;
Tao LIN
1
,
2
,
3
;
Jianfeng SUI
1
,
2
,
3
;
Xinye NI
1
,
2
,
3
Author Information
1. Department of Radiotherapy, Nanjing Medical University Affiliated Second People&rsquo
2. s Hospital of Changzhou, Changzhou 213000 China
3. Jiangsu Province Engineering Research Center of Medical Physics/Center for Medical Physics Nanjing Medical University/Key Laboratory of Medical Physics, Changzhou 213000 China.
- Publication Type:Journal Article
- Keywords:
Esophageal cancer;
Volumetric modulated arc therapy;
Truncated CT;
FOV;
Dosimetric parameters
- From:
Chinese Journal of Radiological Health
2022;31(6):724-730
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the dosimetric effect of truncated regions in computed tomography (CT) images on the targets and organs at risk in volumetric modulated arc therapy (VMAT) for middle thoracic esophageal cancer. Methods CT images of 15 patients with middle thoracic esophageal cancer were selected. Circle masks were used to make the volume of the truncated region account for 10%, 20%, 30%, and 40% of the arm volume, and the corresponding truncated CT images were obtained. The real CT was denoted as CT0. Two radiotherapy plans were made on CT0. One plan was VMAT_1F with full arcs, and the other one was VMAT_3F with arm avoidance. The plans were transplanted to four truncated CT, respectively, and the dosimetric differences between different plans were compared using Wilcoxon signed-rank test. Results Compared with VMAT_1F in CT0, Dmean and V5 of the lung decreased in VMAT_3F, but Dmax of the spinal cord, Dmean of the heart, and V20 of the lung increased. In VMAT_3F, there was no statistically significant difference between the dosimetric parameters in the four truncated CT and those in CT0 (all P > 0.05). In VMAT_1F, except for homogeneity index and Dmax of the spinal cord, the dosimetric parameters in four truncated CT were significantly different from those in CT0 (P < 0.05). The dosimetric difference increased with the increase in truncated region-to-volume ratio. Conclusion Complete CT data should be collected in clinical practice, and the radiation field avoiding the truncated regionshould be set if necessary to reduce the influence of the truncated region on dosimetry.
