[Magnet systems for magnetic resonance tomography]

In the past fifteen years, Magnetic Resonance Tomography (MRT) has become a valuable tool for medical diagnostics. At the same time, Magnetic Resonance Spectroscopy (MRS) has attracted more and more attention in medical and other related areas of investigations. For both methods it is necessary to provide a magnetic field, which can be generated by resistive magnets, by permanent magnets as well as by superconducting magnets. These three concepts are described and compared together with the advantages of each design and the considerations that must be addressed regarding the planned use and the availability of a suitable site. In addition to the main magnet important additions like gradient and shim coils, aspects of site planning and future problems are discussed.