Nuclear magnetic resonance systems
US4449097A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1981 |
| Grant date | May 15, 1984 |
| Priority date | — |
| Expiry date | Jul 15, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4831
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Nuclear magnetic resonance methods have been proposed for examination of large bodies, including medical examination of patients. These include so-called steady state free precession methods. Such methods involve alternating excitation of a region of the body in such a way that an equilibrium condition is established at which a mean resonance signal is detectable. Typically for excitation of a planar region a radio frequency excitation field is provided in the presence of a field having an alternating gradient so that equilibrium is only reached in the plane. It is now proposed to achieve the same result by the application of two radio frequency fields having opposing gradients and pulsed in alternation to balance substantially only in the plane and provide equilibrium only there. The fields are provided by respective sets of saddle shaped coils divided into pairs of unequal dimension (1a, 1b, 2a, 2b) to provide the respective gradients.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.