作　　者： (高行新）; (王洪花）; (陆军）; (李莎）; (张超）; (崔晓磊）; (黄永辉）;

机构地区： 兰州军区兰州总医院放射治疗科,甘肃兰州730050

出　　处： 《中国医学装备》 2017年第9期20-23,共4页

摘　　要： 目的:研究射波刀治疗计划中计算框的大小对靶区剂量分布的影响,为射波刀治疗计划设计时计算框的选择提供参考。方法:选择3个肿瘤最大直径分别为10 mm、30 mm和50 mm的靶区,计算框大小分别为靶区外15 mm、30 mm、50 mm和最大扫描体积,然后进行计划设计,并分析计算框的大小和靶区剂量分布之间的关系。结果:(1)计算时间随着计算框的增大而大幅度减少,而治疗时间随着计算框的增加均有减少的趋势,但变化不大;(2)随着计算框的增大,等剂量曲线数值呈下降的趋势,由开始轻微改变到在最大扫描体积时变化最大,如10 mm靶区,曲线数值由89%~70%,而30 mm靶区,曲线数值由85%~74%,对50 mm靶区,曲线数值由77%~70%。射线束变化趋势和等剂量曲线类似;(3)对不同大小的靶区,适形度会随着计算框的增大而增加,但随着靶区的增大,适形度增加幅度变小。结论:受计算时间和其他靶区剂量分布影响,对于肿瘤直径为10 mm的靶区,计划设计时选择较小的计算框,如靶区外15 mm;对于肿瘤直径为30 mm靶区,选择适中的计算框为宜,如靶区外30~50 mm;而对于肿瘤直径为50 mm的靶区,计算框可以选择大些,如靶区外50 mm或更大范围计算框,可以有效减少计算时间,提高工作效率。 Objective To research the influence of calculation grid size for dose distribution of target region inthe therapy plan of CyberKnife so as to provide references for the choosing of calculation grid in the design oftherapy plan of CyberKnife. Methods： Three target regions which largest diameters were 10mm, 30mm and 50mm,respectively, were selected. The calculation grid sizes were 15mm, 30mm and 50mm out of target region and thelargest scanning volume, respectively. And then, the plan and design were carried out and the relationship betweencalculation grid size and distribution of target dose was analyzed. Results： （1）The calculation time was reducedwith the enlarging of calculation grid and the reduced range was very large, while the treatment time appeareda reducing trend with the enlarging of calculation grid and its change was not obvious. （2）With the enlarging ofcalculation grid, the value of isodose curve appeared a decreasing trend, and the change was slight in begin and wasobvious in largest scanning volume, such as for 10mm target region, the value of curve was from 89% to 70%, and itwas from 85% to 74% for 30 mm target region, and it was from 77% to 70% for 50 mm target region. And the changetrend of bundle of rays was similar with isodose curve. （3）For differently sized target region, the conformal degreewas increase with the enlarging of calculation grid, while its increase range became smaller with the enlarging oftarget region. Conclusion： Based the influence for the consideration of calculation time and other dose distributionof target region, the planning and design should choose smaller calculation grid for the target region of 10mm tumordiameter, such as 15 mm out of target region. And it should choose medium calculation grid for the target region of30 mm tumor diameter, such as 30-50 mm out of target region. Further, it should choose more calculation grid forthe target region of 50 mm, such as 50 or more than 50mm out of target region. This method can reduce calculationtime and

关 键 词： 射波刀 计算框 靶区剂量分布 放射治疗