PET/CT对非小细胞肺癌三维适形放疗中治疗计划参数的影响

目的:观察PET/CT对非小细胞肺癌(NSCLC)三维适形放疗(3D-CRT)中治疗计划参数的影响.方法:对83例在PET/CT定位下拟行根治性3D-CRT的NSCLC患者,分别以CT图像和PET/CT融合图像勾画大体肿瘤靶区(GTVCT和GTVPET/CT),分别制定放疗计划,并对两者进行比较.结果:PET/CT明显改变44例(53.01％)患者GTV或PTV,31例PTV和(或)GTV减小,13例PTV和(或)GTV增加.根据PET/CT和CT分别制定的放疗计划在VGTV、VE50、SCM和ESM的差异有统计学意义,P值分别为0.001、0.001、0.000和0.002.结论:应用PET/CT制定NSCLC3D-CRT治疗计划可降低食管和脊髓的受照射剂量,从而有利于放疗剂量的提升.

Impact of PET/CT on dosimetric parameters of three-dimensional conformal radiotherapy planning in patients with non-small cell lung cancer

OBJECTIVE: To investigate the impact of PET/CT on three-dimensional conformal radiotherapy(3D-CRT) planning of non-small cell lung cancer(NSCLC).METHODS: PET/CT scanning was performed in 83 pathologically proven NSCLC patients for radical radiotherapy.The gross tumor volume(GTV) was delineated on the CT images(GTVCT) alone and then coregestered CT and 18F-FDG-PET data(GTVPET/CT).For each patient,two three-dimensional conformal radiotherapy plans were made: one with a CT-based target volume and one with a PET/CT-based target volume.From the dose-volume histograms and dose distributions on each plan,the dosimetric factors were analyzed and compared.RESULTS: PET/CT clearly altered the radiation therapy volume in 44(53.01%,44/83) cases,while 31 with the reduction of planning target volume(PTV) and/or GTV,and 13 with the enlargement.Between the PET/CT and CT radiotherapy planning,the difference of volume of GTV(VGTV) and dosimetric parameters including esophageal volume receiving at least 50 Gy(VE50),the maximum dose of spinal cord receiving(SCM) and the maximum dose of esophagus receiving(ESM) were statistically significant(P were 0.001,0.001,0.000 and 0.002).CONCLUSION: The incorporation of 18F-FDG-PET information in CT-based radiotherapy planning reduced the radiation exposure of the esophagus and spinal cord,and thus allowed significant radiation dose escalation while respecting all relevant normal tissue constraints.