适形放疗计划评估Ⅱ-Ⅲa期非小细胞肺癌术后放疗的临床剂量学研究

Clinical dosimetry of a conformal radiotherapy plan for evaluating postoperative radiotherapy in stage Ⅱto stage Ⅲ a non-small cell lung cancer

目的探讨非小细胞肺癌(NSCLC)术后三维适形放疗与传统常规照射在临床剂量学方面的差异。方法选取术后存在高危复发因素的Ⅱ-Ⅲa期NSCLC患者30例,分别进行三维适形放疗计划设计和传统常规照射计划设计,通过剂量体积直方图(DVH),比较两种计划中靶区和正常组织的剂量分布优劣。结果三维适形放疗计划的靶区适形指数(TCI)、靶区均匀性(TH)及临床靶区(CTV)最小剂量(Dmin)均明显高于传统常规照射计划(P<0.01),心脏30%等剂量线包绕的计划靶体积(V30)、V40及脊髓CTV最大剂量(Dmax)、平均剂量(Dmean)均明显低于传统常规照射计划(P<0.01),两肺V20、V30及食管V45、V50与传统常规照射计划比较无明显差异(P>0.05)。结论与传统常规照射比较,NSCLC术后三维适形放疗具有明显的临床剂量学优势,可减少心脏、脊髓等正常组织的受照量,但对食管、双肺无明显保护作用。

Objective To analyze the difference in the clinical dosimetry between three-dimensional conformal postoperative radiotherapy and conventional postoperative radiotherapy for non-small cell lung cancer（NSCLC）.Methods A total of 30 cases of stage Ⅱ to stage Ⅲa NSCLC with high-risk of recurrence were selected to formulate a three-dimensional conformal radiotherapy plan and a conventional radiotherapy plan. The dose volume histogram method was used to compare the dose distributions for the target area and the normal tissue in the two plans.Results The target conformal index,target homogeneity, and the minimum dose of the clinical target volume（CTV） in the three-dimensional conformal radiotherapy plan were higher than those in the conventional radiotherapy plan（P0.01）.The maximum dose and the mean dose of heart V30,V40,and spinal cord CTV in the conformal plan were lower than those in the conventional plan（P0.001）;the lung V20,V30,and esophagus V45 and V50 in the conformal plan exhibited no obvious differences compared with the conventional radiotherapy plan（P0.05）.Conclusion Clinical dosimetry revealed that postoperative three-dimensional conformal radiotherapy is significantly better than conventional radiotherapy for NSCLC.Postoperative three-dimensional conformal radiotherapy reduces the reception dosage of normal tissues, including the heart,spinal cord and so on.However,it does not protect the esophagus and lungs.