Gd-enhanced T1-weighted MRI,
C-4DST PET, and
F-FLT PET of two patients. (A) A 76-year-old woman with newly diagnosed glioblastoma (Case 8). Gd-enhanced T1-weighted MR image demonstrates a round lesion with irregular ring enhancement in the right frontal lobe. PET studies with 11C-4DST and 18F-FLT PET show almost identical tracer uptake in the tumor. Background uptake of 11C-4DST is higher than 18F-FLT PET. (B) A 29-year-old woman with recurrent glioblastoma with oligodendroglioma component (Case 20). Gd-enhanced T1-weighted MR image demonstrates multiple spotty enhancements in the right temporo-occipital lobes extending to the basal ganglia. The tumor is faintly visualized with 11C-4DST but well visualized with 18F-FLT. 18F-FLT, 3′-deoxy-3′-[18F]fluorothymidine; 11C-4DST, 4′-[methyl-11C]thiothymidine.