Dynamic SPECT using Tc-99m hexamethylpropyleneamine oxime in the patients with intracranial mass lesions

Dynamic single photon emission computed tomography (SPECT) using Tc-99m hexamethylpropyleneamine oxime (HM-PAO) and N-isopropyl-p[I-123]iodoamphetamine (IMP) was performed in 23 patients with intracranial mass lesions (primary brain tumor; 13, metastatic brain tumor; 6, arterio-venous malformation (AVM); 3, cavernous hemangioma; 1). Instruments used were ring type emission computed tomography (SET-020, Shimadzu Co.) with minicomputer system (ECLIPSE S-120, Japan Datageneral Co.). Dynamic scans were carried out immediately after intravenous injection of the radiopharmaceuticals (2 min. per frame x 10 frames.). Tumor activities (T/N ratios) were calculated in each frame compared to contralateral side. T/N ratios in the patients with angioblastic meningioma, meningothelial meningioma, AVM and high grade astrocytoma were high in early stage, and showed good correlation with those of rCBF image obstained by Xe-133 gas inhalation method (correlation coefficients were 0.9 in HM-PAO, 0.76 in IMP), which seemed to indicate the rate of blood flow in the mass lesions. T/N ratios in metastatic brain tumors and low grade astrocytomas were constant during 0 - 20 min after injection and were not related to tumor types. In summary, dynamic SPECT may be useful method to evaluate the blood flows in brain tumors, and T/N ratios may reflect those of tumors. (author)