(18)F-FDG-PET-CT模拟定位在Ⅲ期非小细胞肺癌放疗中的应用研究

BACKGROUND AND OBJECTIVE: PET-CT have emerged as powerful imaging tools in radiotherapy to add information that might lead to a change in GTV definition in patients with non-small cell lung cancer (NSCLC). The aim of this study was to investigate the impact of co-registering (18)F-FDG-PET-CT images on the gross tumor volume (GTV), the planning target volume (PTV), and critical organ dose in radiation therapy planning of NSCLC. METHODS: Thirty patients with stage Ⅲ NSCLC, referred for radical radiation therapy, underwent PET-CT scanning. GTV was delineated on the CT imaging and PET-CT fused imaging respectively. The two images were used to develop the radiotherapy planning at the GE Advantage Sim 6.0 workstation. Dose-volume histograms (DVH) parameters were selected to be paralleled to compare the quality of the two plans and the impact of PET-CT on radiation plan (RP) was further analyzed. RESULTS: (1) PET-CT image changed the clinical stage: 3 patients (10%) upstaged and 3 patients (10%) downstaged. (2) PET-CT image altered GTV and PTV: GTV and PTV was decreased by PET-CT image fusion in 18 patients (60%) and was increased in 12 patients (40%). A significant (> 25%) treatment volume modification was observed in 17 patients (56.67%). (3) PET-CT image changed the parameters of DVH: to deliver the same target dose of 60 Gy in 30 fractions, all dose-volume characteristics decreased in treatment planning for the 18 patients with decreased PTV based on PET-CT; the issue was the contrary for the 12 patients who had enlarged PTV based on PET-CT. CONCLUSION: The use of the co-registration of PET-CT significantly reduced inaccurate outlining of the GTV and/or to geographic misses.