【摘要】 目的:设计食管癌不同模式下的等中心放疗与三维适形放疗计划,比较重要器官受量和靶区剂量的差别。方法:选取32例中、晚期食管癌病例,按统一标准勾画靶区,在3DTPS上为每个病例设计8组放疗计划,均采用4个共面野(前野、后野、两后斜野)照射。比较指标:肺V5、V20、V30、MLD;心脏Dmean、D60%;靶区VPTV60、VGTV65、VPTV65。结果:①缩野放疗和不缩野放疗比较,靶区适形程度(VPTV60、VPTV65)明显提高,P<0.01;心脏受量降低,但差别无统计学意义,P>0.05。在等中心放疗计划中,缩野放疗比不缩野放疗肺受量明显降低,在V5、V20、V30、MLD上有显著差异,P<0.05。②脊髓最大剂量由40Gy提高至45Gy后,肺受量(V20、MLD)明显降低,P均<0.05;而V5、心脏及靶区剂量的各项指标前后差异均无统计学意义,P>0.05。结论:增加脊髓最大剂量至45Gy后,等中心放疗结合缩野方法,可以使计划在较大程度上优化,进一步降低肺受量,增加靶区适形程度,达到与适形放疗相似的、较好的治疗效果。更多还原

【Abstract】 Objective: To compare the dosimetric difference between isocentric radiotherapy planning and three-dimensional conformal radiotherapy planning in different modes for esophageal carcinoma.Methods: A total of 32 patients with advanced middle-third esophageal carcinoma were enrolled in this study.According to spinal cord dose at two range (below 40Gy and below 45Gy), the technique used (conformal or isocentric), and whether the reduced field was applied, we designed eight plans for each patient.Four coplanar fields were used in all plans.Results: (1) The differences in V5, V20, V30, and MLD between the conformal and isocentric radiotherapy planning were statistically significant (P<0.01).These indices were decreased obviously in the conformal plan.(2) VPTV60 and VPTV65 were increased significantly in reduced field plan compared with that in non-reduced field plan (P<0.01).The indices of the lung were decreased remarkably in isocentric reduced field planning (P<0.05).(3) V20 and MLD were decreased remarkably when Dmax of the spinal cord was increased from 40Gy to 45Gy, but the other indices were not statistically different.(4) V20, V30 and MLD were decreased remarkably in the conformal radiotherapy with reduced field plan or in the plan with Dmax of 45 Gy.Conclusion: Conformal radiotherapy planning outweighs the isocentric radiotherapy in increasing the target conformity and deceasing the dose in the lung and heart, especially in deceasing V5.Isocentric radiotherapy is similar to conformal radiotherapy in deceasing the lung dose and increasing the target conformity when reduced field technique is used and when Dmax of the spinal cord is increased to 45Gy.更多还原