食管癌三维适形放疗与常规放疗的剂量学研究

目的：比较食管癌三维适形放疗与常规放疗在靶区及周围组织器官的剂量分布。方法：对29例首程放疗的食管癌患者同时进行三维适形放疗与常规放疗，并对其剂量学参数进行比较分析。结果：三维适形治疗计划、常规治疗计划的GTV最大剂量分别为6910．7ecy、6883．4cCy，GTV最小剂量分别为5981．2cGy、4776．2eCy，GTV平均剂量分别为6526．7cCy、6430．6cCy，PTV平均剂量分别为6473．0cGy、6262．0cCy，P1rV最小剂量分别为5504．9eCy、3431．9cGy，右肺平均剂量分别为1292．1cGy、1434．5cCy，V20分别为24．8％、28．3％，V30分别为13．0％、16．2％，左肺平均剂量分别为1362．OcGy、1549．8cGy，V20分别为25．3％、30．0％，V30分别为17．0％、20．6％，心脏平均剂量分别为1994．6cGy、2404．6cCy，最小剂量分别为100．2cGy、125．0eCy，40％心脏体积受量分别为2313．8cGy、2648．3cGy，脊髓最大剂量分别为3258．5cGy、4224．1cGy。结论：三维适形放疗技术能够提高肿瘤靶区剂量，并使周围正常组织得到保护。

Dosimetry study on three dimensional conformal radiotherapy and conventional radio- therapy for esophageal carcinoma

Objective：To compare the dose distribution by three dimensional conformal treatment planning system for the target and normal tissues around esophagus carcinaoma in contrast to conventional radiotherapy plan. Methods： Twenty -six patients with untreated esophageal carcinoma were studied before treatment. The three dimensional eonformal treatment plan and conventional treatment plan were used for each patient to assess the outcomes. Results： The maximal dose of GTV was 6910.7cGy and 6883.4cGy for three dimensional conformal treatment plan and conventional radiotherapy plan, respectively. The minimal dose of GTV was 5981.2cGy, 4776.2cGy, respectively. The mean dose of GTV was 6473.0cGy,6262.0cGy,respeetively. The mean dose of PTV was 6473.0cGy and 6262.0eGy for three dimensional conformal treatment plan and conventional radiotherapy plan, respectively. The minimal dose of PTV was 5504.9cGy ,3431.9cGy, respectively. The mean dose of the right lung was 1292.1 cGy, 1434.5cGy , respectively. The V20 ,V30 of the right lung in three dimensional eonformal treatment plan were 24.8 % , 13.0% , in convention- al plan were 28.3% , 16.2% , respectively. The mean dose of the left lung was 1362.0cGy, 1549.8cGy , respectively. The V20 ,V30 of the left lung in three dimensional conformal treatment plan were 25.3% , 17.0% , in conventional plan were 30.0% ,20.6% ,respectively. The mean dose of heart was respectively 1994.6cGy,2404.6eGy. The minireal dose of heart was 100.2cGy,125.0eGy. The 40% volume dose of heart was 2313.8cGy,2648.3eGy,respeetively. The maximal dose of spinal cord was 3258.5cGy,4224. lcGy respectively. Conclusion： Three dimensional conformal radiotherapy technique not only improve the target dose , but also protect the normal tissues around the esophagus earcinaoma.