多发性肝癌质子放射治疗剂量学研究

Dosimetric study of proton therapy for multiple hepatocellular carcinomas

目的被动散射质子治疗(passive-scattering proton therapy,PSPT)是临床最常用的质子放疗方式。调强质子治疗(intensity modulated proton therapy,IMPT)实现了剂量强度的调制,能进一步优化剂量分布,但在多发性肝癌中是否有优势尚不明确。本研究比较PSPT和IMPT在多发性肝癌中靶区剂量分布和正常肝脏受量的差异,为临床应用提供剂量学参考。方法 2013-08-10-2015-11-25淄博万杰肿瘤医院诊断为多发性肝癌患者10例,CT定位扫描,勾画靶区和周围正常组织,分别制定PSTP计划和IMPT计划,两个计划的处方剂量均为60Gy。应用剂量体积直方图(dosevolume histogram,DVH)比较2种不同质子治疗技术靶区的剂量分布和正常肝脏组织的受照剂量。结果 IMPT计划靶区的均匀性指数(homogeneity index,HI,t=3.563,P=0.006)和适形指数(conformal index,CI,t=-7.444,P<0.001)均优于PSPT计划,差异均有统计学意义。IMPT计划正常肝脏V_5(t=6.751,P<0.001)、V_(10)(Z=-2.803,P=0.005)、V_(15)(t=7.232,P<0.001)、V_(20)(t=9.694,P<0.001)、V_(25)(Z=-2.803,P=0.005)、V_(30)(t=8.407,P<0.001)、V_(35)(t=11.667,P<0.001)、V_(40)(Z=-2.803,P=0.005)和正常肝脏平均剂量(mean dose to normal liver,MDTNL,Z=-2.803,P=0.005)均明显低于PSPT计划,差异有统计学意义。结论 IMPT能改善多发性肝癌靶区的剂量分布,并降低正常肝脏的受照剂量,为临床应用提供了重要依据。IMPT有望提高多发性肝癌放疗疗效并降低并发症。

OBJECTIVE Passive-scattering proton therapy（PSPT） is the most commonly used method of proton ra- diation therapy. The intensity modulated proton therapy（IMPT） achieves the dose intensity modulation and can further optimize the dose distribution, but it is not clear whether there is an advantage for multiple hepatocellular carcinoma. This study was to compare different treatment techniques with PSPT and IMPT for the multiple hepatocellular carcinomas, the dose delivered to target volume and normal liver, which provide a dosimetric reference for patients with multiple hepato- cellulsr carcinomas. METHODS Form August 10, 2013 to November 25, 2015, 10 patients with multiple hepatocellular carci- nomas were selected. The PSPT plans and IMPT plans were designed for each patient with the prescribed dose 60 Gy. Dose-vol ume histograms （DVH） was used to compare the dose of target volume and normal liver. RESULTS Homogeneity index （HI） （t=3. 563,P=0. 006）and conformal index （CI）（t --7. 444,P〈0. 001）in IMPT plans were better than those in PSPT plans, the difference was statistically significant. Compared with PSPT plans, IMPT plans reduced the V：, （t= 6.751, P〈20. 001） ,V10 （Z= 2.803,P=0. 005）,V15（t=7.232,P〈0. 001）,V2o（t=9.694,P〈0. 001）,V25（Z--2.803,P： 0. 005） ,V30 （t--8. 407 ,P〈0. 001） ,V3 （t： 11. 667 ,P%0. 001） ,V40 （Z= -2. 803 ,P=0. 005） and the mean dose to normal liver（MDTNL）（Z=-2. 803,P〈0. 005）, the difference was statistically significant. CONCLUSIONS IMPT plan had better target coverage and more superior normal liver sparing than PSPT plan for multiple hepatocellular carcinomas. IM PT may improve the efficacy of multiple hepatocellular carcinomas and reduce complications.