Comparative evaluation of "1"1C-MET PET-CT and MRI for GTV delineation in precision radiotherapy for gliomas

Abstract

Objective To evaluate the difference between MRI and 11C-MET PET-CT for gross tumor volume (GTV) delineation in the precision radiotherapy for gliomas.Methods Six patients with a pathologically confirmed diagnosis of gliomas were selected for target delineation.Five physicians in our department were called to delineate the GTV based on the preoperative MRI and 11C-MET PET-CT images of these patients.The GTVs based on the two methods were compared.Results There was no significant difference between the GTVs based on MRI and 11C-MET PET-CT (P =0.917),and their coefficients of variation were also similar (P =0.600).The coincidences of GTVs were different among the patients,with a maximum value of 73.0％ and a minimum value of 51.8％.GTV showed no significant difference when defined by different physicians on MRI and PET-CT (P =0.709) ; the biggest difference was 27.66 cm3 on PET-CT and 40.37 cm3 on MRI.Conclusions The boundaries of gliomas defined on MRI and PET-CT are different.The GTVs delineated by different physicians on MRI and PET-CT are similar,and the biggest difference on PET-CT is smaller than that on MRI,which suggests that 11C-MET PET-CT is a more direct way for displaying GTV. Key words: Brain neoplasms; Tomography, positron-emission, 11C-methionine; Magnetic resonance imaging; Gross tumor volume delineation