Bolus材质对乳腺癌胸壁电子束放疗剂量分布的影响  

Effect of Bolus materials on dose distribution of electron beam radiotherapy of chest wall of breast cancer

作　　者：吴经 李白威 杨伟强 孔栋[1] 孔燕[1] Wu Jing;Li Baiwei;Yang Weiqiang;Kong Dong;Kong Yan(Department of Oncology Radiotherapy,Affiliated Hospital of Jiangnan University,Wuxi,214122,China)

机构地区：[1]江南大学附属医院肿瘤放疗科,无锡214122

出　　处：《中国医学装备》2024年第9期7-12,共6页China Medical Equipment

摘　　要：目的:评估组织等效物Bolus材质对乳腺癌术后胸壁电子束放疗剂量分布的影响。方法:构建乳腺癌改良根治术后胸壁放疗模型,基于国际原子能机构(IAEA)官网中6 MeV电子束相空间文件(PSF)和Geant4蒙特卡罗应用软件包,计算Bolus材质中水、聚苯乙烯、聚乳酸、甘油和硅胶5种不同材质电子束放疗胸部剂量分布,对比胸壁和肺组织中剂量分布差异。结果:Bolus材质对电子束在胸壁的最大剂量深度(d_(max))影响较小,10 mm厚的Bolus所致d_(max)最大差异约2 mm;对剂量分布产生影响较大,尤其在胸壁后缘和浅表肺组织中,胸壁后缘剂量由大到小对应Bolus材质依次为聚苯乙烯、水、聚乳酸、硅胶和甘油,对于5 mm和10 mm厚的Bolus材质,剂量差异分别约为8%和15%;浅表肺组织中剂量由大到小对应Bolus材质依次是水、聚苯乙烯、聚乳酸、硅胶和甘油,对于5 mm和10 mm厚的Bolus材质,剂量差异最大分别可达约50%和70%。结论:Bolus材质对胸壁电子束放疗剂量分布所产生影响较大,合理选择Bolus材质有助于保证靶区剂量,减少肺组织中剂量沉积。Objective:To assess the effect of Bolus materials(a material has the same effect with tissue)on dose distribution of electron beam radiotherapy on chest wall after surgery for breast cancer.Methods:Radiotherapy model of chest wall after modified radical mastectomy for breast cancer was constructed in this study.Based on the 6 MeV electron beam phase space file(PSF),which came from the International Atomic Energy Agency(IAEA)official website,and the Geant4 Monte Carlo software package,the research calculated the dose distributions of the electron beam radiotherapy of 5 kinds of different materials included water,polystyrene,polylactic acid,glycerol and silica-gel in Bolus materials,and compared the differences of the dose distributions between chest wall and lung tissue.Results:The Bolus materials have a relatively minor effect on the depth of maximum dose(d_(max))of electron beams on the chest wall.The d_(max) maximum difference that was caused by Bolus with 10mm thickness only was 2mm.The Bolus materials with 10mm thickness have a notable effect on dose distribution,particularly in the posterior edge of the chest wall and shallow lung tissue.The order of Bolus materials corresponding to the dose in the posterior edge of the chest wall,from large to small,was polystyrene,water,polylactic acid,silica-gel and glycerol.For Bolus materials with 5 mm thickness and 10 mm thickness,the dose differences were approximate 8%and 15%,respectively.In shallow lung tissue,the corresponding Bolus materials with doses from large to small were water,polystyrene,polylactic acid,silica-gel and glycerol.For Bolus materials with 5 mm thickness and 10 mm thickness,the maximum dose differences were approximate 50%and 70%,respectively.Conclusion:The effect of Bolus materials has larger effect on the dose distribution of electron beam radiotherapy on the chest wall.The reasonable selection of Bolus materials is contributed to ensure the dose of target region,and minimize dose deposition of lung tissue.

关 键 词：组织等效物(Bolus)材质 电子束 剂量分布 乳腺癌 放射治疗 

分 类 号：R814.2[医药卫生—影像医学与核医学]