肺追踪优化对射波刀Synchrony建模的价值

Value of lung tumor tracking optimization methods for CyberKnife synchrony modeling

目的:探讨射波刀肺部追踪肿瘤直径的范围并分析利用肺追踪优化措施对降低Synchrony重建次数的价值。方法:选取152例肺部肿瘤患者执行肺追踪放疗,按肿瘤直径大小分为10 mm≤d<15 mm、15 mm≤d<20 mm、≥20 mm3组。对肿瘤跟踪算法失败的目标分别采用偏移模式、调整跟踪范围、调整不确定性、二次脊柱追踪辅助定位和启用建议影像/主要参考影像进行优化处理,统计优化前后3组能通过Synchrony建模的患者,比较优化前后射波刀治疗过程中Synchrony模型重建的频率。结果:优化前后治疗执行系统能够正确识别肿瘤并通过建模的病例数由10 mm≤d<15 mm组3例(7.5%)、15 mm≤d<20 mm组24例(36.9%)、≥20 mm组43例(91.5%)改变为10 mm≤d<15 mm组8例(20%)、15 mm≤d<20 mm组53例(81.5%)、≥20 mm组45例(95.7%),差异有统计学意义(P=0.047);治疗过程中不优化模型重建频率分别为3.67、1.48和0.47,优化后治疗模型重建频率分别为1.67、0.71和0.33。结论:综合采用肺追踪优化措施,能够降低Synchrony重建次数,对于肿瘤直径在15 mm≤d<20 mm左右的患者有助于治疗的顺利进行;对于肿瘤小于15 mm的患者不建议执行肺部追踪放射治疗。

Objective To discuss the applicability of CyberKnife lung tumor tracking for the tumor diameter,and to explore the value of lung tracking optimization for decreasing the times of Synchrony reconstruction.Methods Totally 152 lung tumor patients undergoing tracking radiotherapy were divided into three groups respectively with the tumor diameters not less than 10 mm while less than 15 mm,not less than 15 mm while less than 20 mm as well as not less than 20 mm.Optimization was executed for the patients with failed tumor tracking,involving in selecting deviation mode,modulating tracking scope,regulating uncertainty,secondary spine tracking aided positioning and adopting preferred projection.The data of the three groups completing Synchrony modeling were summarized before and after optimization,and the frequencies of Synchrony reconstruction before and after optimization were compared during CyberKnife therapy.Results Optimization made the numbers of the cases increased from 3(7.5%)in the group with the diameter not less than 10 mm while less than 15 mm,24(36.9%)in the group with the diameter not less than 15 mm while less than 20 mm and 43(91.5%)in the group with the diameter not less than 20 mm to 8(20%),53(81.5%)and 45(95.7%)respectively,and there were significant differences between the results before and after optimization.The frequencies of the models with no optimization were 3.67,1.48 and 0.47 respectively in the three groups,while the ones after optimization were 1.67,0.71 and 0.33 respectively.Conclusion Comprehensive lung tracking optimization measures contribute to decreasing the times of Synchrony reconstruction,which facilitate the treatment for the patient with the tumor diameter not less than 15 mm and less than 20 mm while are not applicable for the one with the tumor diameter less than 15 mm.[Chinese Medical Equipment Journal,2019,40(3):34-37]