[Emission tomography of the brain (author's transl)]

Emission tomography (ET) is a method for visualization of radionuclide distribution in transaxial section of a body region, especially the brain. Both single-photon emitting and positron emitting radionuclides may be utilized. Conventional radiopharmaceuticals are used for single-photon ET; it shows three-dimensional distribution of radionuclides in normal and pathological brain structures and, when fast scanning techniques are used, permits the quantitative measurement of flow in small brain regions without interference from overprojection of differently perfused tissues. Coincidence detection of short-lived positron emitting radionuclides has the advantage of good attenuation correction so that quantitative determination of the concentration of the radionuclide in small tissue volumes is possible. With these short-lived, usually cyclotron-produced radionuclides, dynamic and metabolic processes may be followed (e.g. regional oxygen consumption with 15O2, regional blood volume with 11CO, C15O or 68Ga, regional perfusion with 13NH3, C15O2 or 77Kr) and the consumption and distribution of labelled organic compounds may be quantified (e.g. local metabolic rate of glucose with 18F-deoxyglucose or glucose distribution with 11C-methylglucose). The clinical application of these techniques may render new insight into pathophysiological mechanisms and the therapeutic management of diseases of the central nervous system.