射波刀治疗中shell1大小对靶区剂量的分布影响研究  

Research on influence of shell1 size on target dose distribution in Cyberknife treatment planning

作　　者：高行新 陆军 李莎 张超 崔晓磊 姜澎 GAO Xing-xin;LU Jun;LI Sha;ZHANG Chao;CUl Xiao-lei;JIANG Peng(Department of Radiotherapy,the 940th Hospital of Joint Logistics Support Force,Lanzhou 730050,China)

机构地区：[1]解放军联勤保障部队第940医院放射治疗科,兰州730050

出　　处：《医疗卫生装备》2018年第11期60-62,69,共4页Chinese Medical Equipment Journal

基　　金：国家自然科学基金青年科学基金(81501623)

摘　　要：目的:研究shell1的大小对靶区剂量分布的影响,为射波刀治疗计划中shell1数值的选择提供参考。方法:选取肿瘤最大直径分别为10、30和50 mm 3类形状规则的代表性靶区,在其他参数不变的情况下,shell1的数值分别选择0、1、2、3、4和5 mm设计治疗计划,然后分析shell1的大小对不同尺寸靶区剂量分布的影响。结果:对肿瘤直径为10 mm靶区,等剂量曲线值在shell1=0 mm时最大,随着shell1的增大呈现先减小后平缓的趋势;适形度随shell1的增大变化较大,呈现先增大后平缓的趋势;正常组织的数值随着shell1的增大呈现先增加后减小的趋势。对肿瘤直径为30 mm靶区,等剂量曲线值没有变化,适形度随着shell1的增大略微增大但变化较小,正常组织数值变化同10 mm靶区一致。对肿瘤直径为50 mm靶区,等剂量曲线值基本没有变化,适形度随着shell1的增大基本上变化不大,正常组织数值变化与10和30 mm靶区基本一致。结论:Shell1的数值大小对小靶区剂量分布影响较大,对大靶区剂量分布影响较小。考虑靶区适形度和覆盖体积等因素影响,建议肿瘤最大直径为10 mm的小靶区,shell1数值取0或者1 mm;而对于肿瘤最大直径为30和50 mm的靶区,shell1根据需要采取适中数值;对于太大或者复杂的靶区,可以采用增大shell1的数值和其他限制条件来得到最优治疗计划。Objective To study the influence of shell1 size on target dose distribution, and provide reference for the numerical selection of shell1 in Cyberknife treatment planning. Methods Three typical targets with 10, 30 and 50 mm tumor diameter were selected respectively, the values of shell1 were set as 0, 1, 2, 3, 4, and 5 （mm） to execute treatment planning, and then the effects of shell1 size were analyzed on the dose distribution of the target area with different sizes. Results For the tumor diameter was 10 mm target： the isodose curve value was the largest at shell1=0 mm, and the tendency dropped first and then turned flatten with the increase of shell1; the conformability showed the trend of first increasing and then gentle; the value of normal tissue changed with the increase of shell1. For tumor diameter was 30 mm target area： no changes occurred in the value of the isodose curve; the conformability showed a trend of first stabilizing and then slightly increasing; the changes of normal tissue values were consistent with those of the 10 mm target area. For tumor diameter was 50 mm target area： the value of the isodose curve was basically unchanged; the conformability basically changed little with the increase of shell1; the trend of normal tissue numerical changes was consistent with those of 10 and 30 mm target areas. Conclusion Shell1 size has less influence on dose distribution at small target area when compared with bigger ones. Factors such as conformal degree and target coverage taken into considerations, the value of shell1 is suggested to be 0 or 1 mm for 10 mm target, to be moderate in case the maximum diameter was 30 or 50 ram, and to be increased with other constraints added in case of excessive or compl icated target.

关 键 词：射波刀 shell1 适形度 肿瘤靶区 剂量 立体定向放射治疗 

分 类 号：R318[医药卫生—生物医学工程] R815[医药卫生—基础医学]