Active shield type of elliptic cylinder-shaped gradient coil for magnetic resonance imaging
US6479998B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 2001 |
| Grant date | Nov 12, 2002 |
| Priority date | — |
| Expiry date | May 23, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4215
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A gradient coil for magnetic resonance imaging (MRI) ha an elliptic cylindrical first coil and a second coil arranged coaxially to the first coil. The second coil is located outside the first coil in the radial direction thereof. The second coil is either elliptic-cylindrical or cylindrical winding positions of wires of the second coil are determined so that a magnetic field created outside the second coil by the first coil is cancelled out. Practically, circumferential current densities of the first and second coils are expressed by weighted even and odd functions. Ratios between weights of the second and first coils are then determined on values derived from the number of waves in the coil axial direction and a flatness rate of the ellipse. The winding positions of wires of the second coil are determined on the values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.