胃癌术后放疗方式对肾脏剂量学影响的比较研究

目的:比较胃癌术后三维适形放疗(3D-CRT)与调强适形放疗(IMRT)对肾脏剂量学的分布影响.方法:选择9例根治术后的进展期胃癌患者,应用Pinnacal三维计划系统(TPS)分别为每例患者设计4野3D-CRT和5、7野IMRT,所有计划给予处方剂量95％的计划靶体积(PTV)＞45 Gy; IMRT同时要求99％的PTV体积＞42.75 Gy.应用等剂量曲线及剂量体积直方图(DVH)比较各个计划之间靶区剂量的分布和肾脏的剂量受量差异.结果:4野3D-CRT和5、7野IMRT的靶区V45分别为0.96±0.03、0.95±0.02和0.95±0.02.所有计划靶区均满足处方剂量,与4野3D-CRT相比,IMRT明显提高靶区的剂量的均匀性(HI)和适形度(CI),并且降低双侧肾脏18 Gy的剂量体积百分比(V18),但在低剂量(10 Gy)体积百分比(V10)3种放射方式之间差异无统计学意义,P＞0.05.5和7野IMRT之间不论在靶区剂量分布还是危及器官的剂量受量上均差异无统计学意义,P＞0.05.结论:与3D-CRT比较,IMRT明显提高靶区均匀性,降低肾脏剂量受量和剂量体积百分比,但在V10上3种计划间差异无统计学意义.

Comparative research of the effect about the renal dosimetry with different radiotherapy after resection of gastric carcinoma

OBJECTIVE: Dose distribution of kidney with intensity-modulated radiotherapy(IMRT),Three-dimensional conformal radiotherapy(3D-CRT) was compared after resection of advanced gastric carcinoma.METHODS: Nine patients who had undergone curatively resected gastic cancer treatment were enrolled for this research.For each patient,four-field 3D-CRT、five-and seven-field IMRT were designed with a prescibed dose of 45 Gy to at least 95% of plan target volume(PTV) by Pinnacal Three-dimensional plan system(TPS),The IMRT plan was required with a prescibed dose of 42.75 Gy at least 99% of PTV at the same time.Dose distribution of PTVs and kidney were compared by using Isodose curves and Dose-volume histograms(DVH).RESULTS:The results of the percentage of volume receiving 45 Gy by PTVs with four field 3D-CRT,five field IMRT and seven field IMRT are 0.96±0.03,0.95±0.02 and 0.95±0.02 respectively.All plans accord with the prescibed dose.The dose distribution of PTVs were comparable,Where IMRT plans achieved better conformity index(HI) and dose uniformity(CI) compared to the 3D-CRT plans.The percentage of volume receiving 18 Gy by bilateral kidney reduced significantly with IMRT plans,Howere as to the percentage of volume receiving lower dose 10 Gy(V10),there was no discrepancy(P>0.05).There was no significantly statistical difference of dose distribution of PTVs and organs at risk(OARs) between 5-and 7-field IMRT(P>0.05).CONCLUSION: Compared with 3D-CRT,a better target dose distribution and significant dose reduction to kidney could be achieved with the IMRT plans.But as to V10,there was no discrepancy between IMRT and 3D-CRT.