肝癌体部γ刀与HT的剂量特点分析

Analysis on the dose characteristics of Body γ Knife and Tomotherapy treatment for hepatocellular carcinoma

目的 分析肝癌在体部γ刀和HT计划中的剂量特点,评估两组计划在OAR保护和全身低剂量区体积大小方面的差异.方法 选取12例已行γ刀治疗的肝癌患者CT定位图像,勾画肿瘤靶区和OAR,分别设计γ刀和HT计划,通过DVH图评估靶区和OAR剂量学参数并配对t检验差异.结果 γ刀组与HT组相比靶区Dmean、Dmax增高（P=0.002、0.000）,适形度降低（P =0.001）,脊髓、左肾Dmax和胃、左肾Dmean降低（P=0.013、0.012、0.010、0.023）,正常组织（全身-PTV）V40、V35、V30 、V25和V20增高（P=0.001、0.001、0.001、0.007、0.029）,肝脏（全肝-GTV）V40、V35、V30、V25增高（P =0.002、0.004、0.008、0.046）,V10、V5降低（P =0.019、0.031）,胃Dmax、右肾和肝脏Dmean相近（P=0.247、0.308、0.401）.结论 两组计划均能符合临床治疗要求.相同剂量下γ刀组靶区Dmean明显高于HT组,但HT组能获得更好靶区适形度,并能更好减少正常组织和肝脏V25-V40,同时也使V5-V10增加.

Objective To study the dose characteristics of Body γ Knife and Tomotherapy treatment plans for hepatocellular carcinoma,and compare their differences between organs at risk （OAR） dose and the range of low dose.Methods CT simulation images of twelve patients with hepatocellular carcinoma were selected,the target volume and OAR were drew by doctor.Body γ Knife and Tomotherapy treatment plans were optimized with their own planning station.The dosimetric characteristics were evaluated by dose volume histograms and were compared.To analyze the difference between the two techniques,the paired t-test was applied.Results The Dmax and Dmean of target with Body γ Knife were higher than Tomotherapy （P =0.002,0.000）,but the conformal index of PTV of Tomotherapy was superior to the Body γ Knife （P =0.001）.The Dmax of spinal cord and left kidney with Body γ Knife was lower than Tomotherapy （P =0.013,0.012）,and it was also in the Dean of stomach and left kidney （P =0.010,0.023）.In the volume dose comparison,the V40,V35,V30,V25 and V20 of normal tissue （all Body-PTV） and liver （all liver-GTV） with Body γ Knife were higher than Tomotherapy （P =0.001,0.001,0.001,0.007,0.029）,but the V10 and V5 were lower （P =0.019,0.031）,the Dmax of stomach,Dmean of right kidney and liver were no statistical difference （P =0.247,0.308,0.401）.Conclusions Both treatment plans could meet the clinical dosimetric need,by the same prescription dose,Dmax and Dmean of target of Body γ Knife were higher than Tomotherapy.Tomotherapy had excellent dose-target conformal and could reduce the range of V25-V40 of OAR and normal tissue,but the range of V5-V10 was increased obviously.