体部γ-刀与3D-CRT在周围型非小细胞肺癌中剂量分布的比较研究

Study on Dose Distribution of Body Gamma-knife and Three-dimensional Conformal Radiotherapy for Peripheral Non-small-cell Lung Cancer

[目的]应用体部γ-刀放射治疗技术和三维适形放射治疗（3D-CRT）技术对周围型非小细胞肺癌实施放疗计划,比较两种治疗方法的剂量学特点.[方法]选择周围型非小细胞肺癌（NSCLC）10例,同时应用体部γ-刀和3D-CRT制定放射治疗计划,治疗方式为2Gy/次,1次/日,5次/周,总剂量为66Gy.计划标准为处方剂量至少覆盖95%的计划靶体积（PTV）,各危及器官剂量均要求在耐受剂量范围内.通过靶区的等剂量分布、剂量体积直方图（DVH）以及靶区适形指数（CI）和均匀指数（HI）等比较肿瘤靶区剂量和正常组织受照射剂量的差异.[结果]3D-CRT计划的PTV的CI、HI优于γ-刀计划,但γ-刀计划周围正常组织的剂量相对较低,全肺的V20、V30均低于3D-CRT.γ-刀PTV最大剂量（Dmax）、平均剂量（Dmean）也优于相应的3D-CRT指标,靶区剂量比3D-CRT计划要高.[结论]γ-刀治疗周围型NSCLC可显著提高靶区剂量,同时很好地保护周围正常组织,在综合治疗中更有提高治疗比的潜能,但其剂量学优势有待于进一步的临床研究验证.

[Objective]To compare the dosimetric features of body gamma-knife vs three-dimensional conformal radiotherapy（3D-CRT） for peripheral non-small-cell lung cancer in order to provide the reference of the clinical choice of radiotherapy techniques. [Methods] Ten patients with peripheral non-small-cell lung cancer were selected. Body gamma-knife and 3D-CRT plans were designed for each patient. The total dose was 66Gy with the dose of 2Gy once a day for 5 times a week. The plan standard was that the prescribed dose covered 95% of planned target volume（PTV） at least. The risk dose was within the tolerated dose. Isodose distribution of target area, dose-volume histogram（DVH）, conformity index（CI） and heterogeneity index（HI） were used to compare the difference between the dose in tumor target area and the radiation dose in normal tissue. [Results] Both CI and HI in PTV area of 3D-CRT plan were better than gamma-knife plan, whereas the dose in normal tissue of gamma-knife plan was relatively lower. V20 and V30 of whole lung of gamma-knife plan were lower than those of 3D-CRT plan. The maximum dose（Dmax） and mean dose（Dmean） of PTV of gam- ma-knife plan were also better than those of 3D-CRT. The target dose of gamma-knife plan was higher than that of 3D-CRT. [Conclusion] Gamma-knife for the treatment of peripheral non-small-cell lung cancer can significantly improve the target dose and protect surrounding normal tissue well. It also has more potential to increase the therapeutic ratio. Nevertheless, the dosimetric advantages of gamma knife should be further verified by clinical research.