Dosimetric impact of dwell position spacing in three-dimensional interstitial brachytherapy plans for cervical cancer
10.3760/cma.j.cn113030-20240718-00276
- VernacularTitle:驻留间距对宫颈癌三维插植后装放疗计划的剂量学影响
- Author:
Wenwen ZHANG
1
;
Yuanjie CAO
;
Jie CHEN
;
Zhiyong YUAN
;
Jiaming ZHANG
;
Zhiyong CUI
;
Zhirong ZHANG
;
Wei WANG
;
Qingxin WANG
Author Information
1. 天津医科大学肿瘤医院放射治疗科，国家恶性肿瘤临床医学研究中心，天津市恶性肿瘤临床医学研究中心，天津市肿瘤防治重点实验室，天津 300060
- Publication Type:Journal Article
- Keywords:
Brachytherapy;
Three-dimensional interstitial brachytherapy;
Treatment planning;
Dwell position spacing;
Uterine cervical neoplasms;
Plan quality
- From:
Chinese Journal of Radiation Oncology
2025;34(5):476-481
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the dosimetric impact of dwell position spacing in the design of three-dimensional (3D) interstitial brachytherapy plans for cervical cancer, and to provide a reference for selecting dwell spacing in clinical planning.Methods:A total of 15 patients with cervical cancer who underwent 3D interstitial brachytherapy at Tianjin Medical University Cancer Institute & Hospital between March 2022 and March 2024 were selected using simple random sampling. For each patient, 10 brachytherapy plans were generated with different dwell position spacings set at 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 mm, respectively. Key parameters among different dwell spacings compared included D 90%, V 100%, V 200%, and V 300% for the high-risk clinical target volume (HRCTV); D 90% for the intermediate-risk clinical target volume (IRCTV); D 2 cm3 for organs at risk (OARs) (bladder, small intestine, colon, and rectum); and the total dwell time. Statistical analyses were performed using repeated measurement ANOVA or the Friedman test. Results:Among different dwell spacings, there were no statistically significant differences in HRCTV D 90%, HRCTV V 100%, bladder D 2 cm3, and rectum D 2 cm3 among different dwell spacings ( P=0.075, 0.061, 0.480, 0.639). All plans with dwell spacings ≤ 3 mm met clinical dose requirements. When the dwell spacing was set to 1 mm, HRCTV V 200% and V 300% had the smallest mean values, while IRCTV D 90% and total dwell time had the largest mean values; all differences were statistically significant ( P<0.05). When the dwell spacing was ≥6 mm, an increase in spacing led to a decrease in mean small intestine D 2 cm3, and total dwell time, but an increase in HRCTV V 200% and a decrease in IRCTV D 90%, with statistically significant differences compared to spacings of 1-4 mm ( P<0.05). When the dwell spacing was ≥8 mm, the median colon D 2 cm3 decreased, with statistically significant differences compared to spacings of 1-3 mm ( P<0.05). Conclusions:For 3D interstitial brachytherapy planning in cervical cancer, dwell position spacings ≤ 3 mm can meet clinical dose requirements, with 1 mm providing optimal target coverage. Spacings ≥6 mm / ≥8 mm can reduce radiation dose to the small intestine and colon, respectively, while also shortening dwell time.
