| Wei Qicheng,Tan Huayan,Li Xianya,et al.A dosimetric study of high-dose region overlapping and cumulative doses in organs at risk in brachytherapy for cervical cancer[J].Chinese Journal of Radiological Medicine and Protection,2026,46(1):70-76 |
| A dosimetric study of high-dose region overlapping and cumulative doses in organs at risk in brachytherapy for cervical cancer |
| Received:June 20, 2025 |
| DOI：10.3760/cma.j.cn112271-20250620-000210 |
| KeyWords:Cervical cancer Brachytherapy Deformable image registration (DIR) |
| FundProject:广西医科大学青年科学基金项目(GXMUYSF202543) |
| Author Name | Affiliation | E-mail | | Wei Qicheng | Institute of Life Sciences, Guangxi Medical University, Nanning 530021, China | | | Tan Huayan | Department of Radiotherapy, Guangxi Medical University Cancer Hospital, Nanning 530021, China | | | Li Xianya | Department of Radiotherapy, Guangxi Medical University Cancer Hospital, Nanning 530021, China | 78598639@qq.com | | Gao Kun | Department of Radiotherapy, Guangxi Medical University Cancer Hospital, Nanning 530021, China | | | Fu Qingguo | Institute of Life Sciences, Guangxi Medical University, Nanning 530021, China
Department of Radiotherapy, Guangxi Medical University Cancer Hospital, Nanning 530021, China | |
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| Abstract:: |
| Objective To explore the overlap of high-dose regions in organs at risk (OARs) during the application of three brachytherapy techniques for cervical cancer using deformable image registration (DIR), to compare the differences in cumulative doses to OARs derived using DIR and the direct superposition method, and to analyze the correlation between these differences and the overlap. Methods A retrospective analysis was conducted for 45 cervical cancer patients who received brachytherapy. Among them, 15, 15, and 15 cases were treated with intracavitary brachytherapy (the ICBT group), intracavitary/interstitial brachytherapy (the IC/IS-BT group), and 3D-printed applicator (the 3D group), respectively. The high-dose regions corresponding to the D2 cm3 and D1 cm3 in the bladder and rectum were generated using the Boolean operations in the planning system. DIR was performed for the interfractional planned CT images, followed by an analysis of the overlap of interfractional high-dose regions in the bladder and rectum using the dice similarity coefficient (DSC). After DIR was conducted for all fractional CT images, the overall overlap of high-dose regions in the bladder and rectum was analyzed using the intersection over union (also known as the Jaccard index). The values of both the DSC and Jaccard index varied from 0 to 1, with lower values representing smaller overlapping regions. Based on a comparison between the deformation-based cumulative doses of all fractional plans derived using DIR and the direct superposition method, the correlations of the dosimetric differences with the DSC and Jaccard index were analyzed for high-dose regions in the bladder and rectum. Results The ICBT, IC/IS-BT, and 3D groups exhibited the DSC values of D2 cm3 and D1 cm3 of 0.470 ± 0.112, 0.452 ± 0.099, 0.412 ± 0.131 and 0.358 ± 0.110, 0.310 ± 0.110, 0.295 ± 0.139, respectively for the bladder, and 0.521 ± 0.159, 0.502 ± 0.118, 0.463 ± 0.141 and 0.411 ± 0.161, 0.365 ± 0.137, 0.347 ± 0.138, respectively for the rectum. These groups showed Jaccard indices of 0.110 ± 0.056, 0.076 ±0.059, 0.083 ± 0.067 and 0.049 ± 0.039, 0.032±0.031, 0.042±0.028, respectively for the bladder, and 0.167 ± 0.130, 0.114 ± 0.089, 0.110 ± 0.094 and 0.107 ± 0.095, 0.057 ± 0.065, 0.056 ± 0.067, respectively for the rectum. Therefore, the three groups showed both low DSC values and low Jaccard indices, with no statistically significant differences. Moreover, there were no significant difference between the cumulative doses to the bladder and rectum derived using DIR and the direct superposition method, demonstrating no correlation with the overlap of high-dose regions. Conclusions There is no significant difference in the overlap of high-dose regions among the three brachytherapy techniques, with no correlation between the magnitude of the overlap and dosimetric differences. The deformation superposition method can serve as an auxiliary approach to assessing the total dose of all fractions in current brachytherapy for cervical cancer. |
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