中下段食管癌三维适形放射治疗的剂量学研究

Three-dimensional conformal radiotherapy dosimetric study for middle and lower thoracic esophageal carcinoma

目的探讨中下段食管癌不同放射治疗方法的优缺点。方法应用Varian Cadplan 6.2三维治疗计划系统,对15例首程放疗中晚期中下段食管鳞癌患者进行研究,为每一病例均设计5种放射治疗计划,分为模拟常规放疗(3野),三维适形放疗(3、4、6个野计划),常规+适形组合计划,即2D-3、3D-3、3D-4、3D-6、2D+3D治疗计划。各计划处方剂量均为66Gy。结果 5种治疗计划在肿瘤控制概率(TCP)、正常组织并发症概率(NTCP)、靶区适形指数(CI)等差异有统计学意义。结论三维适形放疗与常规普放及组合野照射相比,靶区适形指数及肿瘤控制概率提高,脊髓及心脏的受照剂量降低,减少正常组织并发症概率。

Objective To explore the advantages and disadvantages of different radiotherapy plans to middle and lower esophagus carcinoma. Methods The CT image data of 15 esophageal carcinoma patients treated with 3DCRT were studied. 5 kinds of treatment planning protocols were simulated by using three dimensional treatment planning system（Varian Cadplan 6.2） ,which were defined as 2D-3,3D-3,3D-4, 3D-6,2D ＋ 3D. The total radiation dose was 66 Gy. Results Compared with the index of tumor control probability （TCP） , normal tissue complication probability （NTCP） , and conformity index （CI）,the five techniques of radiotherapy had significant differences. Conclusion Three dimensional conformal radiotherapy techniques not only improve the CI and TCP, but also significantly reduce the radiation dose of spinal cord and heart. As a result, the normal tissue complication probability is decreased.