摘要
Abstract
Objective:To compare the dose differences of Acuros BrachyVision(BV)algorithm(based on the linear Boltzmann equation)and the Task Group No.43(TG-43)report algorithm of The American Association of Physicists in Medicine(AAPM)at target area and organ at risk(OAR)in brachytherapy of using various applicators,and to explore the effect of tissue heterogeneity calculation on calculation for dose distribution of brachytherapy.Methods:A retrospective analysis was conducted on 45 patients(30 cases were cervical cancer,8 cases were lung cancer,and 7 cases were tumor of lymph node metastasis)who underwent three-dimension(3D)brachytherapy at Cancer Center of Suining Central Hospital during October 2023 and December 2024.The Acuros BV algorithm based on the linear Boltzmann equation and the purity water dose algorithm of AAPM Task Group No.43(TG-43)report were respectively used to calculate the dose distribution of the radiotherapy plans of 45 patients.The dosimetric differences of target area dose among three kinds of applicators(single tube applicator for 15 cases,Manchester-type applicator for 15 cases,and titanium interstitial needle for 15 cases)were compared and analyzed in two kinds of algorithms,as well as the dosimetric differences at OAR(Bladder:Dmax,D2cm3,Rectum:Dmax and D2cm3,Small bowel:Dmax and D2cm3)between single tube applicator and Manchester-type applicator in two kinds of algorithms.Results:The D95%doses of target area of single tube applicator were respectively(5.65±0.13)Gy and(5.76±0.14)Gy in using Acuros BV and TG 43,and the D90%doses were(6.01±0.10)Gy and(6.18±0.11)Gy.The doses of target area of TG 43 algorithm all were higher than those of Acuros BV algorithm,and the differences were significant(t=2.19,3.50,P＜0.05).The D95%values of target area of Manchester-type applicator were respectively(4.98±0.29)Gy and(5.35±0.32)Gy in using Acuros BV algorithm and TG43 algorithm,and D90%values were(5.49±0.26)Gy and(5.90±0.28)Gy,and the dose of target area of TG-43 algorithm was higher than that of Acuros BV algorithm(t=3.3,4.13,P＜0.05).The D95%dose values of target area of titanium interstitial needle plans were respectively(20.84±1.19)Gy and(21.98±1.07)Gy in using Acuros BV and TG43 algorithm,and D90%dose values were(24.44±1.35)Gy and(25.67±1.35)Gy,and the differences were statistically significant(t=2.74,2.50,P＜0.05).The D95%and D90%values of TG43 were higher by 5%than those of Acuros BV algorithm.Furthermore,for the OAR dose of Manchester-type applicators,there were significant differences at bladder D2cm3,rectum Dmax,and rectum D2cm3 between the two kinds of algorithms(t=2.44,2.17,2.54,P＜0.05).The dose value of TG43 algorithm was higher by 7.43%-11.26%than those of Acuros BV algorithm,and there were not statistically significant differences at other OAR dose(P＞0.05).Conclusion:The TG-43 algorithm does not consider of tissue heterogeneity,which leaded to generally overestimates doses of the target area,and OARs such as the bladder and rectum.The materials of three kinds of applicators were different,so the degree of overestimating dose was different.Especially,Manchester-type applicator and titanium interstitial needle applicator should be cautiously evaluated.Therefore,we should try to use Acuros BV or Monte Carlo and other heterogeneity algorithm to conduct dose calculation.关键词
线性玻尔兹曼方程(Acuros BV)算法/美国医学物理师协会TG43号(AAPM TG43)报告/近距离治疗/后装施源器/组织非均匀性Key words
Linear Boltzmann equation(Acuros BV)algorithm/American Association of Physicists in Medicine Task Group NO.43(AAPM TG43)Report/Brachytherapy/Rear mounted applicator/Tissue heterogeneity分类
医药卫生
