The Advancement of Nuclear Medicine : Cerebral Blood Flow Imaging by SPECT(Recent Progress in Medical Imaging)

The imaging of cerebral metabolism is important for diagnosis and treatment of cerebral vascular disorders. Recently, single photone emission computed tomography (SPECT) and new several radio-pharmaceuticals have been developed for cerebral metabolic imaging. Especially, one of the most usefull radio-pharmaceuticals is N-isopropyl-p (^<123>I) iodoamphetamine (IMP). There is still more unknown portion in tracer kinetics of ^<123>I-IMP, though, it is thought to be true that early SPECT images of ^<123>I-IMP show the distribution of regional cerebral blood flow. And it is also an advantage of ^<123>I-IMP to be able to measure regional cerebral blood flow (rCBF) by the modified arterial blood sampling method. On early SPECT images of ^<123>I-IMP in the ischemic cerebral vascular disorders, the low perfusion area usually consists of three or four parts differing in severity. The regional blood flow (rCBF) of the area corresponding to the low density area, peri-low density area and normal density and low perfusion area on X-ray CT are 15ml/100g・brain/min, 34ml/100g・brain/min and 46ml/100g・brain/min, respectively. The redistribution phenomenone is frequently observed on delayed ^<123>I-IMP SPECT images. This phenomenone is especially observed in the area in which rCBF is between 25 to 35ml/100g・brain/min