Nmr system for the non-invasive study of phosphorus metabilism

Abstract

A nuclear magnetic resonance analytic apparatus for obtaining tissue metabolism information from a living body member. The apparatus consists of a large high-intensity electromagnet with an inner space having a uniform magnetic field, for receiving the body member. The space has a probe coil mounted therein with which the body member is engageable. For phosphorus-31 metabolite, there is provided a 24.33 MHz RF generator connected through a control logic section and a driver unit to the probe coil via a transmitter/receiver switching unit arranged to in effect switch the probe coil from a normal connection with a demodulation circuit to the driver unit responsive to a burst of RF pulse energy applied to the switching unit by the driver unit via the control logic section by command of a computer. The control logic section controls the system so as to first apply short pulses of the RF signal to the probe coil for a predetermined excitation time period, gating-off the demodulation unit. After this excitation period, the transmitter circuit is disabled, the demodulation circuit is gated-on, and the switching unit restores the normal connection of the probe coil to the demodulation unit, allowing the free induction decay signals sensed by the probe coil to be demodulated and furnished in analog form to the computer, which converts these analog signals into representations of the intensities versus frequency shift of the respective metabolite components of the tissue. Means is provided for applying a predetermined simulated free induction decay signal to the demodulation circuit for testing the apparatus.