原发性肝癌结合双呼吸时相三维适形放射治疗的剂量学研究

Dosimetric Study of Two-phase for Three-Dimensional Conformal Radiotherapy in Primary Liver Cancer

目的:研究原发性肝癌结合双呼吸时相的三维适形放射治疗(放疗)计划与自由呼吸计划的剂量学参数比较。方法:入选患者进行呼吸训练,分双时相与自由呼吸进行CT定位,勾画靶区,TPS计划设计,摆位验证双呼吸时相技术应用于原发性肝癌放疗的可行性。比较计划靶体积、正常肝脏的平均剂量、照射量大于23Gy的肝脏的体积比的剂量学参数。结果:15例入选该研究的患者均配合良好。采用双呼吸时相结合形成的PTV为(385.9±206.1)cm3,自由呼吸的PTV为(556.8±281.1)cm3,(P<0.01);双呼吸时相技术的平均MDTNL为(16.9±4.9)Gy,而自由呼吸则为(22.7±6.3)Gy(P<0.01);双呼吸时相技术和自由呼吸的V23分别为32.9%和45.3%。结论:双呼吸时相技术用于肝癌适形放疗是可行的。该技术能减少正常肝的照射体积,降低平均剂量,较好地保护了患者的正常肝脏。

Objective：To compare two plan＇s dosimetric parameters of three-Dimensional Conformal Radiotherapy （3D-CRT） for primary liver cancer（PLC）＇s plans,one plan is combined with static exhalation phase and static inhalation phase （two-phase）,and another is in free breathing（FB）.Methods：PLC patients received Breathing training,two sequences of CT images was on two-phase,one sequences of CT images was on FB.The doctor draw the two targets,two 3D-CRT＇s plans were genetated,set-up errors of patient position were evaluated by comparisons of electronic portal image（EPI）and digital reconstructive graph（DRR）,Compared dosimetric parameters of the two plans include planning target volume（PTV）,mean dose to normal liver（MDTNL）and the percentage of liver volume which received radiation dose more than 23Gy（V23）. Results：15 patients were eligib1e for this study.PTV-2P was （385.9±206.1）cm3,and PTV-FB was （556.8±281.1）cm3.MDTNL of two-phase was （16.9±4.9）Gy,MDTNL of FB was （22.7±6.3）Gy.V23 were 32.9%and 45.3%.Conclusion：The technology of two-phase was feasible.use of the technology could decrease irradiated liver volume and MDTNL,Better protection of the patients with normal liver.