三维适形放疗与调强放疗在不同肺叶非小细胞肺癌中的剂量学研究

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IMR...

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(3DCRT) 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 3DCRT 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.