Investigations of brain tumours with 99Tcm-HMPAO SPECT

The cerebral uptake of Tc-hexamethylpropyleneamine oxime (Tc-HMPAO) as measured with the use of single photon emission computed tomography (SPECT) was studied in 66 patients with various types of brain tumours and quantified by tumour-to-cerebellum ratios. The uptake of Tc-HMPAO by gliomas and meningiomas showed wide ranges of values. There were no significant differences among primary malignant gliomas (0.75±0.27, n = 25), recurrent malignant gliomas (0.81±0.25, n = 14) and benign gliomas (0.77±0.21, n = 9). Compared to gliomas, meningiomas exhibited a significantly higher Tc-HMPAO uptake (1.14±0.31, n = 13, p < 0.001) while the remaining four patients with tumours of various histopathology showed a low Tc-HMPAO uptake. Three of the 66 patients were scanned immediately and again 2 h after injection and they revealed a decrease in tumour activity. No changes in the pattern of uptake were observed in two patients with gliomas which were studied before and after intra-arterial chemotherapy, but a decrease in tumour uptake was found in the glioma patient who was studied before and after radiotherapy, The results obtained with Tc-HMPAO SPECT are in agreement with those on regional cerebral blood flow (rCBF) in brain tumours reported in the literature.