Biomedical subjects
Publications and source records attributed to W E Timms.
Installing high-field magnets in hospital environments has implications for safety, for the performance of the equipment and for the well-being of the subjects who will be examined. This paper outlines the relevant properties of magnets and identifies the requirements necessary for a safe and usable installation. One approach to the meeting of these requirements is described.
The object of this paper is to inform prospective users of clinical NMR equipment about the various magnets which may form the heart of the system. The peripheral magnetic field of the magnet must be considered when the site is planned and prepared. Some of the planning criteria are discussed with respect to the magnet, and its ancillary equipment and services.
A pragmatic approach to interference in NMR and MRI systems is presented with the objective of raising the awareness of problems associated with larger installations. The basic premise is that an installation is a system composed of interconnected sub-systems, each with its own idiosyncracies. Consequently all problems should be considered from this view-point. Practical warnings and solutions are given along with simple mathematical equations to permit one to calculate some interference effects. Most problems are associated with RF and gradient sub-systems, so the main content deals with degradation of the NMR signal by noise and coherent RF interference and with the interaction of sub-systems. Attention is drawn to the correct identification of the source of a problem, and the importance of a well engineered solution. 'Quick-fix repairs' can lead to very baffling problems when the system is reconfigured for a different experiment.