食管癌放射治疗胸部组织校正与否对剂量学影响的研究

Research on that Making Breast Tissues Correction or No Impacts on Dosimetry Distribution in Esophageal Carcinoma Radiotherapy

目的:探讨不均匀胸部组织校正与否对食管癌癌患者的肿瘤靶区、正常组织及重要器官剂量分布的影响。方法:选择21例病理证实的食管癌癌,每个病例同时设计两组治疗计划,模拟常规放疗不校正不均匀胸部组织计划、三维适形放疗校正不均匀胸部组织计划。常规计划为照射60 Gy,通过调节剂量权重使处方剂量与常规放疗的相同;射野大小、及其他参数与常规放疗的相同,此时得到常规计划的剂量分布就是常规不校正不均匀肺组织在患者体内的实际分布。三维计划为三维适形放疗照射60 Gy。将常规计划与三维计划进行比较。结果:两组治疗计划临床靶区的最大值、平均值、95%体积剂量和100%体积剂量的均数有显著性差异(p<0.05);适形度指数值的均数有显著性差异(p<0.05);脊髓最大值,两肺V5、V20的均数有显著性差异(p<0.05);均匀性指数值和两肺平均值的均数无显著性差异(p>0.05)。结论:食管癌三维适形放疗,可使肿瘤获得比常规放疗更理想的剂量,更好地保护正常组织。

Objective： In order to probe that making non-uniform breast tissues correction or no impacts on dose distributions of carcinomatous target volumes, normal tissues and important organs of esophageal carcinoma patients. Methods： Choosing 21 cases of patients with esophageal carcinoma, we design two radiotherapy plans for each of them. One is conventional plan without making non-uniform breast tissues correction, and the other is 3-dimension conformal radiation therapy （3DCRT） plan with non-uniform breast tissues correction. In the first plan, the dose is 60 Gy. Through adjusting dose weights, we make prescribed dose equal to conventional radiotherapy dose. If irradiation field size and other parameters are still the same as conventional radiotherapy parameters, then we obtain actual dose distribution in patient＇s body which equal to the dose distribution of conventional plan. In 3DCRT, the dose is 60 Gy too. At last, we compare the dose distribution between conventional plan and 3DCRT plan.Results： There are significant differences between two plans （p 〈 0.05） as we have compared Dmax, Dmean, dose of 95% volume and dose of 100% volume; the conformity indexes also show a considerable difference （p 〈 0.05）; it is also remarkably different （p 〈 0.05） in Spinal cords＇ Dmax and two lungs＇ V2o. However, the differences in HI, V5 and Dmean of two lungs are not very significant since p 〉 0.05. Conclusions： In esophageal carcinoma radiotherapy, the dose distribution of 3DCRT is better than that of conventional treatment. Thus, 3DCRT can protest normal tissues better than regular radiotherapy.