Correlation between dose distribution and implantation duration of 125I seed strand under the simulated curvature of the cavity condition
10.3969/j.issn.1008-794X.2025.11.009
- VernacularTitle:模拟腔道弧度条件下125I粒子链剂量分布与留置时间相关性研究
- Author:
Zezhou LIU
1
;
Dingxin WANG
;
Guozhang XING
;
Jinxin ZHAO
;
Ke XU
;
Hongtao ZHANG
;
Juan WANG
Author Information
1. 050051 河北石家庄 河北省人民医院(河北省肿瘤放射性粒子植入诊疗中心、河北省放射性粒子近距离治疗研究所)肿瘤一科
- Keywords:
125I seed strand;
intracavitary tumor;
absorbed dose;
brachytherapy
- From:
Journal of Interventional Radiology
2025;34(11):1213-1217
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the relationship between the absorbed dose and implantation duration at the target area and at the critical organ dose reference points in the application of radioactive 125I seed strands for the treatment of intraluminal tumors.Methods A self-developed 125I seed strand arc template with a 30-degree angle was used to place 10 seeds(each with activity of 1.0mCi)into the template.CT-based DICOM images were transferred to a treatment planning system(TPS)for dose calculation.Absorbed doses at multiple time points(from day 5 to day 90 with a 5-day interval)were measured at following four specific locations:point A'(5 mm inside the arc center),point A(5 mm outside the arc center),point B(10 mm outside the arc center),and point B'(10 mm inside the arc center).The TPS was first used to calculate the expected absorbed doses,followed by actual absorbed dose measurements over the 90-day period.The expected absorbed doses were calculated,and then the actual absorbed doses were calculated.The time-dose relationship of the above points was analyzed,and the curves and equations were obtained.Results The expected absorbed doses at points A',A,B,and B'were 221.36,196.39,115.78,and 136.32 Gy,respectively.The time(x)-dose(y)relationships of all the above points followed a quadratic function relationship in the form of y=c+bx-ax2.Within the time range of 5-90 days,the actual absorbed dose increased with the prolongation of time,and the increase speed showed a pattern of first fast and then slow.The increase in speed was fast within 20 days,than became stable between 20-75 days,and after 75 days the increase in speed became to slow down.Conclusion When using 125I seed strands to treat intraluminal tumors,the actual absorbed dose of the tumor needs to be accurately calculated based on the implantation duration.The actual absorbed dose initially accumulates rapidly and decreases significantly after 75 days.It is recommended to replace the 125I seed strand with a new one after implanting it for approximately 75 days.
