Active-passive electromagnetic shielding to reduce MRI acoustic noise
US7375526B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Oct 20, 2006 |
| Grant date | May 20, 2008 |
| Priority date | — |
| Expiry date | Dec 22, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4215
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including passive shielding located outside the actively shielded gradient winding elements in order to reduce the magnitude of fields that spread outside the gradient coil assembly in unwanted directions and interact with the magnet cryostat or other metallic magnet parts, inducing eddy currents that cause consequent acoustic noise. The passive shielding elements are conducting layers located on the outer radius of the cylindrical gradient coil assembly in a cylindrical magnet system, conducting layers located at the ends of the gradient coil assembly in a cylindrical magnet system, and conducting layers located inside the actively shielded gradient winding inner elements in a cylindrical magnet system. The passive shielding could also be located on separate structures that are vibrationally isolated from the magnet cryostat. The actively shielded gradient winding can also be extended to portions at the ends of the actively shielded gradient winding and further to portions inside the inner radius of the inner portion of the actively shielded gradient winding. The actively…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.