[Value of 11C-methionine and PET in the diagnosis of low grade gliomas].

Ten patients with low grade glioma were examined with positron emission tomography (PET) using 11C-methyl-L-methionine (11C-Met). In 4 cases, follow-up study was performed after radiation therapy. 11C-Met uptake index was calculated by sequential arterial blood sampling and PET image on 45 minutes after injection. The tumor was clearly seen in the images, and uptake index in the tumor lesion was higher than that in the normal cortex. The uptake of 11C-Met was observed in a recurrent lesion that was confirmed by operation. 11C-Met uptake indices were decreased in the tumor lesions after radiation therapy. From these results PET with 11C-Met is a useful clinical tool for diagnosis of low grade gliomas.