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[Positron emission computed tomography and cerebrovascular disorders: significance and principles of the technic, first applications in cerebrovascular diseases].

Positron emission computed tomography is a new technic allowing to map the functional state (metabolism and circulation) of a given human organ. By using the coincidence detection of annihilation radiation emitted by positron emitting radionuclides and applying the three-dimensional reconstruction technic to the regional radionuclide distribution in the tissue, it yields an image of the distribution of a previously administered radionuclide in any desired transverse section of the body and allows through already developed mathematical models the precise measurement of local values of metabolism and circulation. This approach appears to be especially promising for the study of the nomal and diseased brain. It circumvents many of the problems of conventional radionuclides and detection systems. Principles, interest and first results of the technic in relation to cerebrovascular problems are presented.