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.