The aims of this study were to assess the clinical usefulness of [Tc-99m] tetrofosmin (TF) single photonemission computed tomography (SPECT) and X-ray transmission computed tomography (CT), performedsimultaneously with a hybrid imaging device for the functional anatomical mapping of brain tumors andto evaluate the additional information of SPECT/CT when compared to SPECT alone. Thirty (30) patientswere studied: 20 were evaluated before undergoing surgery and 10 after surgery and before radiotherapyplanning. The acquisition of both functional (SPECT) and morphologic (CT) images were obtainedin a single session. SPECT images were firstly evaluated alone and then reinterpreted by adding theanatomical (CT) planes. Fusion imaging was successfully obtained in all patients with precise correspondencebetween SPECT and CT slices. SPECT/CT had a significant clinical impact in 13 (43.3%) of30 cases; in particular, SPECT/CT accurately characterized eight lesions near sites of physiological uptake(i.e., four near ventricles/choroids plexus, three near venous sinuses, one near the skull) and localizedviable tumor tissue in 5 patients evaluated after surgery. SPECT/CT with TF using this hybrid devicerepresents a useful clinical tool in brain tumor imaging, both correctly categorizing focal areas nearsites of physiological uptake and localizing viable tumor tissue after surgery. [ABSTRACT FROM AUTHOR]