High-frequency system for nuclear spin tomography with shield for delimitation of an electric field

摘要

A high-frequency apparatus for nuclear spin tomography includes a high-frequency antenna arrangement in the region of a biological body to be imaged. Such an apparatus often exhibits an undesirable electric field coupling between the antenna arrangement and the body. To avoid the effects of such a coupling, the present invention provides at least one plate-shaped or layer-shaped shielding element consisting of a dielectric material with an epsilon r of at least 50 and a tan delta of at most 2.5x10-2. This shielding element is arranged at least in a region of increased electric field strength prevailing on the antenna arrangement.