Method of site shimming on permanent magnets
US5003276A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1989 |
| Grant date | Mar 26, 1991 |
| Priority date | — |
| Expiry date | Aug 11, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/3873
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Ferromagnetic pieces are mounted on a plurality of nonmagnetic radial rods located at desired locations parallel to a pole face of a permanent magnet used in a magnetic resonance imaging apparatus. The pieces comprise plates which are translatable radially along each rod. Each rod carrying the plates are each rotatable about the rod axis to produce an error field cancelling environmentally induced, low order perturbations. A method for accomplishing same is also included. In a preferred embodiment, the plates are mounted on radial rods positioned at equal angles from one another, preferably thirty degrees (30.degree.) apart and arranged as spokes of a wheel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.