[Single photon emission tomography (SPECT). Cerebral function diagnosis for the clinical routine. Indications and radiotracers]

Nuclear medicine techniques have been powerful tools in neurology since their introduction. Computed tomography, magnetic resonance imaging and newer techniques, i.e. MR spectroscopy and angiography, sonography, Doppler sonography and EEG mapping with squid elements have overtaken most earlier nuclear medicine techniques for neurological diagnosis. Positron emission tomography is the gold standard for in vivo research in neurophysiology and pathology. The introduction of SPECT and the development of such tracers as 99mTc-HMPAO (99mTc-d,l-hexamethylpropylenaminoxim) and, more recently, 123I-iomazenil and 123I-IBZM (123I-3-iodo-6-methoxybenzamide) allowed closer examination of the perfusion of the brain and neuroreceptor density mapping in more than the few institutions that can afford PET and the production of special tracers marked with a positron emitting nucleus. Nuclear medicine's future will be based on neuroreceptor density mapping, as further tracers will become commercially available and no other technique can probably show such low concentrations of the receptors. Probably MR techniques will be used for brain's perfusion measurement in future. For examination of a limited cerebral region xenon-enhanced CT is an alternative to perfusion measurements with HMPAO, or a very interesting supplement. Of the old techniques in nuclear medicine, examination of the liquor dynamics is still feasible and well supplemented by SPECT.