非小细胞肺癌放射治疗不同模式的剂量学分析

Analysis of different models of non-small cell lung cancer radiotherapy dosimetry

目的分析常规放射治疗计划、三维适形放射治疗(3DCRT)计划和调强适形放射治疗(IMRT)计划治疗非小细胞肺癌(NSCLC)的疗效,评估3DCRT和IMRT与常规治疗的优越性。方法对经病理证实的50例中晚期NSCLC(Ⅲ～Ⅳ期)患者进行回顾性分析,计划靶区处方剂量66Gy,利用治疗计划系统(TPS)对每例患者分别设计常规、3DCRT和IMRT三种放疗计划,通过剂量体积直方图,比较三种计划对肿瘤靶区和正常组织器官的剂量分布。结果 (1)靶区适行度:处方剂量为66Gy时,三维适形放射治疗和调强适形放射治疗达此剂量的计划靶区(PTV)体积和95%PTV体积下的照射剂量均高于常规治疗,同时,调强适形放射治疗均高于三维适形放射治疗。(2)除全肺V20的IMRT检测外,3DCRT和IMRT治疗的肺受剂量均比常规治疗高。在全肺V5和全肺V10检测中,3DCRT比IMRT剂量低,其余检测中3DCRT比IMRT剂量高。(3)三种计划脊髓最大受照剂量均<45Gy。脊髓,食管及心脏受照剂量3DCRT均较常规放疗低,并且差异均有统计学意义(P<0.05)。结论 (1)3DCRT和IMRT较常规放射治疗明显提高了靶区的照射剂量和靶区的准确性,从而在相同处方剂量情况下提高了治疗肿瘤的控制率。(2)3DCRT和IMRT与常规放疗比较,对肺的保护性存在一定的局限性。(3)3DCRT和IMRT在一定程度上可降低正常组织受照剂量和并发症的发生概率,减少正常组织的放射损伤。(4)IMRT在靶区剂量分布上明显优于常规放射治疗和3DCRT,同时能在一定程度上更好的保护正常组织。

Objective Retrospectively studying the effect and comparing of dose distribution among ordinary radiotherapy plan,three dimensional conformal radiation therapy plan and intensity modulated radiotherapy plan for patients with non-small cell lung cancer（NSCLC）.Evaluated the superiority among the plans.Methods 50 patients with NSCLC proved pathologically were selected into the study.All patients were treated with the same treatment planning system（TPS） and the ordinary radiotherapy plan,3DCRT plan and IMRT plan were made for each patient with the treated dose for the planning conformity of 66Gy.Through the dose volume histogram,the comparison is made of which three plans have effects on the dose distribution of the cancer conformity and the normal tissues.Results（1） The conformity index（CI） CI：for the planning conformity of 66Gy,PTV of 3DCRT which reached the dose is higher than ordinary therapy,and so is IMRT.Meanwhile,it is found that by using IMRT,there is a higher PTV of reaching the dose than 3DCRT.（2）The accepted doses of lung of IMRT and of 3DCRT are all higher than that of the ordinary radiotherapy,except the value of V5.The V5 and V10 of IMRT is lower than these of 3DCRT,the rest of the values are opposite.（3）The accepted dose for critical organ of these three plans are all under 45Gy.The accepted doses for critical organs,the esophageal and the heart of 3DCRT are lower than the ordinary radiotherapy,there is a significant difference.Conclusions（1）3DCRT and IMRT improve the target volume dose and accuracy by comparing with ordinary radiotherapy,thus they reduce the incidence of tumor in the same prescription.（2） Comparing the with ordinary radiotherapy,3DCRT and IMRT exist some limitations in the aspect of protection lung.（3） 3DCRT and IMRT can reduce the accepted dose of normal tissue and incidence of complications to some extent.Thus they can decrease the damage of normal tissue.（4） Comparing with the ordinary radiotherapy and 3DCRT,the IMRT planning has a better dose distribution.Meanwhile it can protect normal tissue better.