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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)>45Gy;IMRT同时要求99%的PTV体积>42.75Gy。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18Gy的剂量体积百分比(V18),但在低剂量(10Gy)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。
Objective: To compare the effects of three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated conformal radiotherapy (IMRT) on the distribution of renal dosimetry in patients with gastric cancer. METHODS: Nine patients with advanced gastric cancer undergoing radical surgery were enrolled. Four fields of 3D-CRT and 5,7 fields of IMRT were designed for each patient using the Pinnacal 3D planning system (TPS). All planned doses of 95% of the planned target Volume (PTV)> 45 Gy; IMRT requires 99% of the PTV volume to be> 42.75 Gy. Isodose curves and dose-volume histograms (DVHs) were used to compare dose distributions across the various plans with those of the kidneys. Results: The target areas V45 of 4-field 3D-CRT and 5,7-field IMRT were 0.96 ± 0.03, 0.95 ± 0.02 and 0.95 ± 0.02, respectively. Compared with 4-field 3D-CRT, IMRT significantly improved the homogeneity of dose (HI) and conformality (CI) in the target area and decreased the dose-volume percentage of 18 Gy in bilateral kidneys V18). However, there was no significant difference between the three radiation modes of low dose (10Gy) (V10). There was no significant difference between the three dose groups (P> 0.05.5) and the seven IMRT The difference was not statistically significant, P> 0.05. Conclusion: Compared with 3D-CRT, IMRT significantly improves the uniformity of the target area and decreases the dosage of kidney dose and the percentage of dose volume. However, there is no significant difference in V10 among the three plans.