Siemens Helicon: a novel 2 tesla superconducting whole-body MR magnet

A superconducting 2-T magnet for whole-body magnetic resonance imaging and spectroscopy has been developed as a serial product. The authors summarize the extensive function and safety tests that have been performed during the development on two complete units and one cryostat model. The so called HELICON magnet has a very stable suspension system for the helium vessel and radiation shield. Loops of glass-fiber-reinforced plastic with limited heat conduction are used to take up medium forces. Forces exceeding a certain level are taken up by bump stops. The construction of the magnet is based on finite-element calculation methods. The mechanical structure was tested on a 1:1 scale room temperature cryostat model with careful recording of accelerations, forces, and displacements. The tests included behavior under extreme transport conditions and a 15-cm free-fall of one magnet end. Component tests were performed at liquid-nitrogen temperature. The test results confirmed that the HELICON magnet can be shipped cold without taking more precautions than disconnecting the refrigerator. >