A dosimetric study of 3D intracavitary brachytherapy in combination with applicator-guided IMRT boost for cervical cancer
10.3760/cma.j.issn.1004-4221.2017.12.014
- VernacularTitle:宫颈癌三维腔内放疗同步体外施源器引导下IMRT剂量学研究
- Author:
Xinyu ZHAO
1
;
Jing ZHAO
;
Fei GU
;
Tianlong JI
;
bing XIA
;
Shuo ZHANG
;
Lei YAO
;
Guang LI
Author Information
1. 中国医科大学附属第一医院放疗科
- Keywords:
Cervical neoplasms/three-dimensional brachytherapy;
Cervical neoplasms/intensity-modulated radiotherapy;
Dosimetry
- From:
Chinese Journal of Radiation Oncology
2017;26(12):1421-1425
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the dosimetric feasibility of three-dimensional(3D)intracavitary brachytherapy in combination with applicator-guided intensity-modulated radiation therapy(IMRT)boost for patients with locally advanced cervical cancer who have unfavorable topography following external beam irradiation. Methods A total of 7 patients with locally advanced cervical cancer who had unfavorable topography following external beam irradiation were included. Two plans were generated for brachytherapy using Oncentra 4.3 treatment planning system:3D intracavitary brachytherapy and 3D intracavitary brachytherapy in combination with applicator-guided IMRT boost.To further evaluate cumulative doses to organs at risk(OAR)in the four fractions of combined plans,two methods were used:simple dose-volume histograms(DVH)parameter addition and deformable image registration(DIR)-based DVH accumulation. The D90, V100, and conformity index(CI)were evaluated. The paired t-test or Wi1coxon signed rank test was used for statistical analysis. Results Compared with the 3D plan,the combined plan yielded higher D90, V100, and CI(P=0.000), but showed no significant difference in D2ccof the rectum,sigmoid colon,and bladder(P>0.05). There were also no significant differences in D2ccof the rectum, sigmoid colon, and bladder calculated by the two methods for calculating OAR cumulative doses, simple DVH parameter addition and DIR-based DVH accumulation(P>0.05). Conclusions For patients with cervical cancer who have unfavorable topography following external beam irradiation,3D intracavitary brachytherapy in combination with applicator-guided IMRT boost can improve target coverage and CI, without increasing OAR doses. DIR-based DVH accumulation and simple DVH parameter addition may be both acceptable for assessing OAR cumulative doses.
