Technetium-99m sestamibi brain single-photon emission tomography for detection of recurrent gliomas after radiation therapy

Technetium-99m sestamibi (MIBI), an alternative radiopharmaceutical for myo cardial perfusion imaging, has also been proposed for use as an imaging age nt for various tumours, including breast cancer, lung cancer, lymphomas, me lanomas and brain rumours. After routine radiation therapy, deteriorating c linical status or treatment failure may be due to either radiation-induced changes or recurrent tumour. Computed tomography and magnetic resonance ima ging offer imperfect discrimination of tumour viability and radionecrosis. Against this background we undertook a retrospective study of 35 malignant glioma patients in whom clinical deterioration had occurred, in order to cl arify the value of Tc-99m-MIBI SPET in identifying tumour recurrence. SPET was performed 15 min after intravenous injection of 1110 MBq Tc-99m-MIBI. T he images were obtained with a dual-headed gamma camera using a fan-beam co llimator. Transverse, coronal and sagittal views were reconstructed. Intens e MIBI uptake was found in 31 patients. This uptake was correlated with tum our recurrence as proved by histology and/or rapid, fatal evolution of thes e cases. The statistical analysis performed on this population of patients with MIBI uptake revealed a group of patients with a long mean survival and a group with a short mean survival. Two subgroups were found within each o f these groups, according to the functional index ratio (tumour uptake/pitu itary gland uptake ratio). No MIBI uptake was found in four patients who ar e still alive and can be considered to be disease-free. In those cases show ing MIBI uptake, death occurred an average of 6.69 months following brain S PET. According to our results, the specificity and sensitivity of Tc-99m-MI BI brain SPET seem to be high. Moreover, this technique is more accurate th an computed tomography or magnetic resonance imaging for discriminating bet ween tumour recurrence and radionecrosis.