基于D2SRS微光栅系统的早期非小细胞肺癌体部立体定向放射治疗计划设计

Stereotactic body radiotherapy plan based on D2SRS micro collimator system for early stage nonsmall cell lung cancer

目的探讨基于D2SRS微型光栅对于早期非小细胞肺癌体部立体定向放射治疗的计划设计及临床应用的可行性。方法选取2015年6月至2016年1月间石家庄市第一医院收治的2例早期非小细胞肺癌患者,基于调强放疗技术(intensity-modulated radiation therapy,IMRT)设计体部立体定向放射治疗计划,分析对比Elekta Synergy VMAT 10mm多叶光栅与D2SRS 2mm微型光栅2种计划模式下靶区和危及器官所接受的剂量。结果基于D2SRS 2mm微型光栅的治疗计划与目前临床常规应用的ELekta Synergy VMAT 10mm多叶光栅计划相比进一步优化了治疗计划质量,适形度及均匀度提高,肺和脊髓等危及器官中剂量降低了。结论 D2SRS微型光栅系统可以用于早期肺癌体部立体定向放射治疗,其2mm的等中心叶片厚度相对于10mm多叶光栅计划,对靶区有更好的适形性和剂量跌落梯度,危及器官的剂量更低。

Objective To research the feasibility of stereotactic body radiotherapy （SBRT） plan based on D2SRS micro collimator system for early stage lung cancer. Methods Two patients with early stage non-small cell lung cancer （NSCLC） treated at First Hospital of Sbijiazhuang City from June 2015 to Januray ：2016 were selected. The two patients received SBRT which was designed based on intensity-modulated radiation therapy （IMRT）. Dose distribution inside the target volume and organs at risk （OARs） were analyzed and compared between Elekta Synergy VMAT 10 mm multi leaf collimator （MLC） and D2SRS 2 mm micro collimator system. Results Compared with the routine clinically used Elekta Synergy VMAT l0 mm MLC, the D2SRS 2 mm collimator plan further optimized the treatment efficacy including conformation and evenness and reduced the dose to OARs for lung and spinal marrow. Conclusion It is feasible to apply D2SRS 2 mm collimator in SBRT for lung cancer. The thickness of 2 mm leaf at isocenter for D2SRS makes better conformal and dose falling gradient near targets compared with 10 mm MLC with less dose to OARs.