Evaluation of actual doses to bladder and rectum during image-guided volumetric modulated arc therapy for cervical cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第2期
- Page:
- 142-145
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Evaluation of actual doses to bladder and rectum during image-guided volumetric modulated arc therapy for cervical cancer
- Author(s):
- NI Xiaolei1; CHEN Rongqin2; BAI Penggang2; CHEN Wenjuan2; WENG Xing3; LIN Xiurong2; LI Qixin2; DAI Yitao2; CHEN Kaiqiang2; CHEN Jihong2; ZHANG Weiting
- 1. Longyan First Hospital, Fujian Medical University, Longyan 364000, China; 2. Fujian Tumor Hospital, Fujian Medical University, Fuzhou 350014, China; 3. School of Nuclear Science and Technology, University of South China, Hengyang 421001, China
- Keywords:
- ; Keywords: cervical cancer; cone beam computed tomography; image-guided radiotherapy; bladder; rectum; translational setup error; dosimetric change
- PACS:
- R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.02.004
- Abstract:
- Abstract: Objective To evaluate the effects of translational setup errors on the doses to bladder and rectum during image-guided volumetric modulated arc therapy for cervical cancer. Methods Twenty-five patients receiving volumetric modulated arc therapy for cervical cancer from February 2017 to April 2017 were enrolled in this study. Bladder and rectum were delineated on the planning computed tomography (CT) images and the cone beam CT (CBCT) images obtained in the first treatment fraction. Then, bladder and rectum were shifted in the anterior-posterior, left-right, and superior-inferior directions according to the first setup errors. The planned dose of bladder and rectum were compared by those data obtained with CBCT images considering setup errors, and the dosimetric differences were compared with paired t-test. Results The rectum volumes delineated on the planning CT and CBCT images were (33.0±16.0) cm3 and (21.8±16.5) cm3, respectively, and the bladder volumes were (387.1±222.3) and (227.8±107.3) cm3, respectively. The V50 of rectum based on the planning CT and CBCT images was (17.27±13.42) % and (23.9±26.58) %, respectively; and the V50 of bladder was (33.59±12.2) % and (44.27±22.61) %, respectively, with statistical differences (t=-3.60, P<0.01; t=-2.98，P<0.01). The maximum dose of rectum based on the planning CT and CBCT images was (5 324±383) and (5 370±441) cGy, respectively; and the maximum dose of bladder was (5 547±365) and (5 513±328) cGy, respectively, with no statistical differences (t=-1.18, P=0.20; t=0.66, P=0.51). Conclusion During the radiotherapy course for cervical cancer, the volumes and doses of bladder and rectum in planning CT are significantly different from those in the first treatment fraction. CT images should be obtained for multiple fractions to evaluate the dose distribution and further assess the benefits of radiotherapy.
Last Update: 2019-02-26