The impact of 125I seeds strand length on different reference points dose
10.3969/j.issn.1008-794X.2025.06.009
- VernacularTitle:粒子链长度对周围不同参考点剂量的影响
- Author:
Ke XU
1
;
Dingxin WANG
;
Guozhang XING
;
Huimin YU
;
Jinxin ZHAO
;
Zezhou LIU
;
Zeyang WANG
;
Hongtao ZHANG
;
Juan WANG
Author Information
1. 050051 河北石家庄 河北省人民医院肿瘤一科
- Keywords:
treatment planning system;
seeds strand;
dose;
reference point;
brachytherapy
- From:
Journal of Interventional Radiology
2025;34(6):609-613
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effect of different strand lengths of 125I seeds with the same activity on the dose of different reference points around the seeds.Methods The scanned images were transferred to the three-dimensional treatment planning system(3D-TPS)according to DICOM format.The target volume was delineated at 5 mm and 10 mm above and below the center of the phantom,and a 0.8 mCi seeds strand was simulated.The 1-20 seeds were arranged with an equal spacing of 5 mm(5 mm-100 mm).The 5 mm points above and below the center of the seeds strand were defined as point A and point A',and the 10 mm points above and below the center were defined as point B and point B'.5 mm above and below the edge of the seeds strand on the left side were defined as AL points and AL'points,and 5 mm above and below the edge of the seeds strand on the right side were defined as AR points and AR'points.Similarly,points 10 mm above the above mentioned positions were defined as BL points,BL'points,BR points,BR'points.The average dose symmetry points were measured at AL,AL',AR,and 5 mm,10 mm,15 mm and 20 mm inside AR' of the 45 mm-100 mm seeds strand.The dose at the center was compared with the dose at the end points.The dose at the center point A was compared with the average dose at the symmetry points of 5 mm,10 mm,15 mm and 20 mm inside of the end points AL,AL',AR and AR',and the dose at each point was curve fitting.The correlation between each point and seeds strands of different lengths was analyzed.Results There was a positive correlation between the dose and the length of each point.There was no statistically significant difference between the center point and the end point.There was a statistically significant difference in dosage at points 5 mm and 10 mm inside from point A,while there was no statistically significant difference in dosage at points 15 mm and 20 mm inside from point A.The dose of A,A',B and B' point increased steadily with the increase of seed chain length,and the fitting curves were obtained respectively:y=e(-0.620/x+5.28)(R2=0.992),y=e(-0.640/x+5.34)(R2=0.987),y=e(-0.82/x+4.80)(R2=0.984),y=e(-0.82/x+4.83)(R2=0.9g1).Conclusion The doses at points A,A',B,and B'are positively correlated with seeds strand length and have a high degree of stability.Point A can be used as a reference point for the target area dose of the seeds strand,and point B can be used as a reference point for the dose to critical organs.The dose at other positions is more variable and thus has a certain degree of uncertainty as a reference point for the seeds strand dose.
