Cryogenic MRI magnets
US5701112A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1995 |
| Grant date | Dec 23, 1997 |
| Priority date | — |
| Expiry date | Nov 13, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/3815
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electromagnet for use in MRI apparatus comprising an annular vessel inside which annular windings energizable to produce a magnetic field are contained together with iron components, hereinafter termed cold iron, which components are mechanically anchored with respect to the windings, and iron shim rings positioned externally of the vessel within its annular bore, hereinafter termed warm iron, the size and relative position of the shim rings being chosen so that instability of the magnetic field introduced by one shim ring, due to vibration or temperature changes, is substantially compensated for by an equal and opposite effect produced by one or more other shim rings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.