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目的:对比研究胃癌术后患者辅助割裂野单中心半野适形放疗(3D-SF-CRT)、三维适形放疗(3D-CRT)及前后对穿野常规放疗(AP-PA)的剂量学特点。方法:在放疗计划系统为有术后辅助放疗适应证的胃癌患者15例设计相同计划靶体积(PTV)下的3种放射治疗方案,处方剂量均为45 Gy,根据剂量体积直方图(DVH)计算并比较3种放疗方法各参数的标准差。结果:3种放疗技术的计划靶区的V95、D95差异无统计学意义(P值分别为0.521和0.241),2种适形放疗技术的适形指数差异无统计学意义(P=0.189),但均高于AP-PA,P=0.02。3D-SFCRT、3D-CRT和AP-PA的脊髓最大点剂量分别为(33.24±0.45)、(35.01±0.48)和(51.90±0.92)Gy,P=0.06。3D-SFCRT的双肾V20~V45均小于其他2种放疗技术,P<0.05。3D-SFCRT的肝脏V25~V45比3D-CRT高,但差异均无统计学意义,P=0.261。3D-SFCRT的右肾T5/5明显低于3D-CRT,P值分别为0.001和0.008;在左肾、脊髓及肝脏,差异无统计学意义,P值均<0.05;与AP-PA相比,3D-SF-CRT的脊髓、双肾的T5/5明显为低,P值均<0.05;在肝脏两者类似,P=0.261。结论:胃癌术后辅助放疗,与常规适形放疗技术相比,应用割裂野单中心半野适形照射技术能在确保PTV获得满意剂量分布的同时,更好地保护脊髓及双侧肾脏,值得推广。
Objective: To compare the dosimetry features of 3D-SF-CRT, 3D-CRT and anteroposterior routine radiotherapy (AP-PA) in postoperative patients with gastric cancer. . Methods: Fifteen patients with gastric cancer who had postoperative adjuvant radiotherapy indications were enrolled in the study. Three radiotherapy regimens with the same planned target volume (PTV) were designed. The prescribed dose was 45 Gy. According to the dose-volume histogram (DVH) The standard deviations of the three radiotherapy methods were calculated and compared. Results: There were no significant differences in V95 and D95 between the three radiotherapy techniques (P values were 0.521 and 0.241, respectively). There was no significant difference in conformal indices between the two conformal radiotherapy techniques (P = 0.189) (P <0.05), but both were higher than that of AP-PA. The maximal dose of spinal cord in 3D-CRT and AP-PA were 33.24 ± 0.45, 35.01 ± 0.48 and 51.90 ± 0.92 Gy, P = 0.06.3D-SFCRT in both kidneys V20 ~ V45 were less than the other two radiotherapy techniques, P <0.05.3D-SFCRT of liver V25 ~ V45 higher than 3D-CRT, but the difference was not statistically significant, P = 0.261. The 3D-SFCRT of right kidney T5 / 5 was significantly lower than that of 3D-CRT, with P values of 0.001 and 0.008, respectively. There was no significant difference in left kidney, spinal cord and liver between the two groups , And the spinal cord of 3D-SF-CRT and T5 / 5 of both kidneys were significantly lower, both P <0.05; P = 0.261 in the liver. Conclusions: Compared with conventional conformal radiotherapy, postoperative adjuvant radiotherapy for gastric cancer can effectively protect the spinal cord and bilateral kidneys while ensuring a satisfactory dose distribution of PTV and is worth promoting .