中心型非小细胞肺癌三维适形放疗与调强放疗治疗计划比较

Comparison of treatment planning between three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for central non-small cell lung cancer

目的:对比研究中心型非小细胞肺癌(NSCLC)三维适形放疗(3D-CRT)和正向调强(fIMRT)及逆向调强(iIM-RT)放疗计划特点,为中心型NSCLC放疗计划制定提供指导。方法:选择拟行根治性放疗的21例中心型NSCLC患者进行3D-CRT、fIMRT和iIMRT治疗计划设计,对3种治疗计划的相关剂量学参数进行比较。结果:3D-CRT、fIMRT和iIMRT治疗计划的适形指数(CI)差异有统计学意义,P=0.000;均匀性指数(HI)差异也有统计学意义,P=0.032。全肺V20和全肺平均受照剂量(MLD)差异均无统计学意义,P值分别为0.896和0.926;全肺V10和全肺V35组间差异均有统计学意义,P值分别为0.001和0.022;全肺V15和全肺V30组间差异为临界值,P值分别为0.058和0.051。心脏Dmean组间差异无统计学意义,P=0.989;心脏V40组间差异也无统计学意义,P=0.934。食管V45组间差异无统计学意义,P=0.708。脊髓Dmax组间差异无统计学意义,P=0.216。结论:对中心型NSCLC而言,采用iIMRT可以获得更好的靶区适形度,但iIMRT计划的剂量均匀性优势并不显著。iIMRT对中心型NSCLC正常肺组织的影响需要辨证看待,其并没有显著降低全肺V20和MLD而且增加了全肺V10、V15及键侧肺V5、V10、V15,但其显著降低了全肺V30。iIMRT没能使中心型NSCLC患者心脏、食管及脊髓受照剂量显著下降。

OBJECTIVE：To investigate the dosimetric characteristics of treatment planning of three-dimensional conformal radiotherapy,forward intensity-modulated radiotherapy, inverse intensity-modulated radiotherapy for central non-small cell lung cancer （NSCLC） to serve as guideline in clinical practice of treatment planning making for central NSCLC. METHODS.. The treatment planning of three-dimensional conformal radiotherapy （3D-CRT）, forward intensity-modulated radiotherapy （fIMRT） and inverse intensity-modulated radiotherapy （iIMRT） were separately designed on the CT simulation image of the selected twenty-one patients with central NSCLC who were prescribed to receive radical radiotherapy. The advantage and disadvantage of the three different treatment planning were compared based on the dosimetric characteristics. RESULTS：The difference of CI between three groups was statistically significant （P= 0. 000）, HI （P = 0. 032）. The difference of V20 and MLD of the whole lungs were all not statistically significant （P value were 0. 896 and 0. 926 ,respectively）, but statistically significant for V10 and V30 （P value were 0. 001 and 0. 022, respectively）, statistically marginally significant for V15 and V30 （P value were 0. 058 and 0. 051）. The difference of D of the heart between three groups was not statistically significant （P=0. 989） ,also V40 of the heart （P=0. 934）. There was not statistically significant between the groups for V40 of the esophagus （P=0. 708） ,and for Dmax of the spinal cord （P=0. 216）. CONCLUSIONS： For central NSCLC, the better conformal index （CI） of the target can be formed by iIMRT, but the advantage of heterogeneity index （HI） of iIMRT is not more marked. We need to treat the influence of iIMRT in a dialectical perspective on the normal lung tissue for the patients with NSCLC. In iIMRT planning, V20 and MLD of the whole lung is not been decreased and V10 and V15 of the whole lung and Vs, V10 and V15 of the opposite lung is also not been decreased, but V30 of the whole lung is been markedly increased. The named dosage for the heart, esophagus and spinal cord in iIMRT planning does not markedly decrease for the patients with central NSCLC.