201TI SPECT FOR EVALUATION OF BRAIN TUMORS AS COMPARED WITH 123I-IMP SPECT AND 18F-FDG PET

Abstract

Clinical usefulness of 201T1 SPECT for evaluation of brain tumors was studied in comparison with 123I-IMP SPECT and 18F-FDG PET.201T1 SPECT and 123IMP SPECT were performed in 73 patients with brain neoplasm (group 1) and 15 patients with non-tumor cerebral diseases (group 2). Among them, 31 patients in group 1 and 5 patients in group 2 received 18F-FDG PET. SPECT was done with a ring type machine (HEADTOME SET011) and PET with a neuro PET (PCT H1).Forty-eight of 73 (65.8%) patients in group 1 showed increased accumulation of 201T1 in tumor site, whereas only 9 (12.3%) patients showed increased radioactivity of 123I-IMP in the lesion. Eighteen of 31 (58.1%) patients with neoplasm demonstrated increased regional cerebral metabolic rate of glucose (rCMRgl) in the lesion. Only two out of 15 (13.3%) patients with non-tumor lesion demonstrated increased accumulation of 201T1. None of them showed accumulation of 123I-IMP or increased rCMRgl. Patients with malignant neoplasm demonstrated higher uptake of 201T1 in the lesion than those with benign neoplasm or non-tumor lesions. Post-therapeutic patients with glioblastoma or metastatic tumors showed lower 201T1 uptake than before therapy. Superimposed images of both 201T1 and 123I-IMP resemble rCMRgl functional images, suggesting increased 201T1 radioactivity in viable tumor tissue with decreased radioactivity in surrounding areas.201T1 SPECT is useful for diagnosis of brain tumors and evaluation of effectiveness of therapy or evidence of residual tumor tissue. It may differentiate malignant tumors from benign tumors or non-tumor intracranial diseases including radiation injury and detect tumor recurrence earlier.