High power, multiple-frequency transmit-receive switch in magnetic resonance imaging
US6198288A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1998 |
| Grant date | Mar 6, 2001 |
| Priority date | — |
| Expiry date | Nov 25, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/3628
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic imaging apparatus includes an RF coil (F) in electrical communication with an RF signal generator (C) and a receiver (G) through an interface circuit (E). The signal generator transmits resonance excitation signals at one of at least two resonance frequencies, e.g. the resonance frequencies of hydrogen helium 3, fluorine, phosphorous, carbon, or xenon. During the transmit cycle, PIN diode (30) is forward biased forming a filter at a first resonance frequency, electrically isolating the receiver from first frequency excitation signals. Simultaneously during the transmit cycle, PIN diode (32) is forward biased forming a filter at a second resonance frequency electrically isolating the receiver from second frequency excitation signals. During a receive cycle, the diodes are reverse biased turning both filters into low impedance circuits around the first and second resonance frequencies allowing a received magnetic resonance signal to pass unimpeded from the RF coil to the receiver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.