A comparative study of 11C-MET PET with MRI for target volume delineation in postoperative radiotherapy for brain high grade glioma

Abstract

Objective To evaluate the value of L-(methyl-11C)-labeled methionine positron emissions tomography (MET PET) and MRI in target volume delineation for postoperative radiotherapy for brain high grade glioma (HGG).Methods Thirty-seven patients with supratentorial HGG were included.Both MRI and MET PET scan were performed in the same treatment position for all patients.The consistency to determine residual tumor between MRI and MET PET was analyzed.Imaging data of MET PET and MRI were coregistered using the BrainLAB image fusion software.The extension of the volume with high uptake (VMET) on MET PET were compared quantitately with the enhancing area on MRI T1W gadolinium enhancement (VGd) and the hyperintensity area on MRI T2W (VT2).Results Both MET PET and MRI were positive for 19 patients and negative for 7 patients.The consistency between these two scans was 70.3%.MET PET was integrated with MRI in 30 patients with positive MET uptake.VMET were partially or entirely outside VGd in 29 patients and VT2 in 17 patients, whereas VGd and VT2 were partially or entirely outside VMET in all patients.The maximal distance from the margin of VMET to VGd was ≥ 2.0 cm in 50%patients and the corresponding distance of VMET to VT2 was ≥ 1.0 cm in 33% patients.Conclusions The differences are existing between MET PET and MRI in determination and identification of the location and extension of residual tumor for patients with HGG.The integration of MET PET and MRI can accurately delineate radiation target volume. Key words: Brain neoplasm; Tomography,positron emissions,11C-labeled methionine; Magnetic resonance imaging; Radiation target volume