三维适形放疗与调强放疗在不同肺叶非小细胞肺癌中的刘量学研究

目的比较不同肺叶非小细胞肺癌（NSCLC）的调强放疗（IMRT）和三维适形放疗（3DCRT）的剂量学特点。方法以肿瘤位于上叶（上叶组）及下叶（下叶组）的各10例接受根治性放疗的NSCLC患者为研究对象，分别制定5野IMRT计划及3—5野3DCRT计划，应用剂量体积直方图评估两组治疗计划，分别比较上叶组、下叶组IMRT与3DCRT计划之间的剂量学参数。结果1）上叶组、下叶组的IMRT计划的以下指标优于相应的3DCRT计划，差异均有统计学意义（P〈0．05）：PTV参数、适形指数、异质性指数、平均肺剂量及肺V10～V65、食管Dmean及V55、心脏V40、食管的早晚期正常组织并发症发生率；2）IMRT计划比3DCRT计划平均降低了上叶组约2．7％的肺V5值及下叶组约1．1％的V5值，但差异无统计学意义（P〉0．05）；3）与3DCRT计划比较，上叶组、下叶组的IMRT计划的食管V35、心脏Dmean均较低，在上叶组的差异有统计学意义（P〈0．05），在下叶组的差异无统计学意义（P〉0．05）。结论在NSCLC的根治性放疗中，5野IMRT较3DCRT更能提高靶区的剂量分布均匀性，在保护正常组织器官方面也显示出较明显的优势；且IMRT应用于上叶NSCLC的优势有可能大于下叶者。

A Dosimetric Study of Three Dimensional Conformal Radiotherapy and Intensity Modulated Radiotherapy for Different Pulmonary Lobes of Non-Small Cell Lung Cancer

Objective To compare the dosimetry characteristics of intensity modulated radiation therapy （IMRT） and three dimensional conformal radiotherapy （3 DCRT） with different pulmonary lobes of non-small cell lung cancer （NSCLC）. Methods The study was performed to compare IMRT and 3DCRT of 10 patients with NSCLC in the upper lobes （the upper lobe group） and 10 patients with NSCLC in the lower lobes （the lower lobe group）. All the patients would receive radical radiotherapy. In the IMRT plans, five coplanar beams were designed. Three to five coplanar beams were designed for 3DCRT plans. The two series of plans were evaluated by the dose volume histogram. The differences of dosimetry parameter were analyzed too. Results 1 ）The indices of IMRT plans were superior to the 3DCRT plans of NSCLC in the upper lobe group or the lower lobe group,the difference was statistically significant （P 〈0.05 ） ,including the indices of PTV,conformity index, heterogeneity index, mean lung dose, V10：V65 of lung parenchyma, V55 and mean dose of esophagus, V40 of heart, acute and late normal tissue complication probability of esophagus ;2） compared with the 3 DCRT plans, the average V5 of lung was degraded about 2.7 % in the upper lobe group, and 1.1% in the lower lobe group, but the difference was not statistically significant （ P 〉 0.05 ） ; 3 ） compared with the 3DCRT plans,the IMRT plans of NSCLC in the upper lobe group,the difference of V35 of esophagus and mean dose of heart were statistically significant （P 〈 0.05 ）, but of NSCLC in the lower lobe group, the difference was not statistically significant （P 〉 0.05 ）. Conclusion For the patients with NSCLC who received radical radiotherapy, the five beam IMRT plans can have better dose uniformity and protect the normal organ better than the 3DCRT plans. The application of IMRT for NSCLC located in the upper lobes may be superior to the lower lobes.