精确放射治疗中改进的楔形挡板剂量修正算法  

Improved Corrected Algorithm of Wedge Factors in Accuracy Radiotherapy

作　　者：兰海洋[1,2] 郑华庆[1,3] 李贵[1,3] 宋钢[1,3] 程梦云[1,3] 吴宜灿[1,3,4] 

机构地区：[1]中国科学院等离子体物理研究所,安徽合肥230031 [2]合肥工业大学应用物理系,安徽合肥230009 [3]安徽省精确放疗工程技术研究中心,安徽合肥230009 [4]中国科学技术大学核科学技术学院,安徽合肥230027

出　　处：《原子核物理评论》2010年第1期77-81,共5页Nuclear Physics Review

基　　金：国家自然科学基金青年基金资助项目(30900386);安徽省自然科学基金资助项目(090413095)~~

摘　　要：在精确放射治疗中,精确计算楔形挡板的楔形因子是精确修正加入楔形挡板后剂量值的关键。提出了基于衰减系数法思想的改进楔形野剂量修正算法,首先计算了楔形挡板材料的线性衰减系数,再根据楔形挡板的实际剖面尺寸,建立了线性拟合公式计算射线束穿过楔形挡板的实际厚度,精确计算楔形因子,并以AAPM55号报告提供的45°楔形挡板进行了验证。该方法在保证计算精度的同时减少了大量离轴测量数据,减轻了物理师的负担,可以作为一种有效的楔形挡板修正算法应用于放射治疗计划系统中。In accuracy radiotherapy,it is difficult to calculate dose accurately during wedge fields.In this paper,an improved corrected algorithm of wedges based on the line-attenuation was proposed.The line-attenuation coefficient of wedges was calculated firstly,then the actual path of radial beam in the wedge was calculated by the ＂linear fitting＂ according to the sizes of wedges section.Finally the wedge factors could be determined accurately,and the dose could be corrected.The data of the 45 degree wedge in the report of AAPM 55 were used to make the calculation and verificaton.Using this algorithm,amount of measured data were decreased,the accuracy of calculation could be assured,and the job of physician could be reduced,so this algorithm could be applied in the treatment planning system as an effective calculation method of wedges field.

关 键 词：精确放射治疗 楔形挡板 楔形因子 线性衰减系数 剂量计算 

分 类 号：R815.6[医药卫生—放射医学]