Method for magnetic field gradient eddy current compensation
US4698591A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1986 |
| Grant date | Oct 6, 1987 |
| Priority date | — |
| Expiry date | Jan 3, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/385
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is provided for characterizing the spurious, time-dependent magnetic field gradient response and for compensating therefor. In accordance with the method a small sample object is placed away from the system isocenter where the gradient to be compensated is non-zero. A magnetic field gradient pulse is applied to the sample, followed by the application after a variable time of a 90.degree. radio frequency pulse. The phase of the resulting free induction decay (FID) signal is monitored as a function of total time since the end of the gradient pulse. These data are related to the gradient impulse response and are fit to a set of (e.g., two or three) exponentials by regression techniques wherein an initial estimate is improved in one embodiment by chi-squared minimization of a Taylor's series expansion about the initial estimate point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.