System and method for measuring temperature in a strong electromagnetic field

Abstract

A system for monitoring the temperature of a patient undergoing an examination in strong magnetic field, such as that created by an MRI machine. The system includes a temperature sensor composed of a high accuracy temperature probe that is coupled to an electronics module by an RF current reduction network. The temperature sensor is excited by a constant current provided on two of the four leads comprising the RF current reduction network. The remaining two leads connect to an instrumentation amplifier. All of the circuitry is located within a Faraday housing, and all connections made between the sensor and the electronics module pass through RF filters mounted in the Faraday housing, allowing the electronics module to be positioned within the strong magnetic field. The temperature measurement signal provided by the instrumentation amplifier is pulse-width modulated and supplied to a fiber optic transmitter for transmission along a fiber optic cable to a temperature monitor located outside of the strong magnetic field. At the temperature monitor, a fiber optic receiver converts the received signal to an electrical signal for display of the measured temperature. In an alternative embodiment, a low battery signal is generated when the voltage of the battery powering the electronics module falls below a predetermined threshold. The low battery signal is combined with the temperature signal by a summing amplifier and the combined signal is transmitted to the temperature monitor. The temperature monitor then separates the two signals for display of the measured temperature and the battery status.

Dependencies are inferred from the claim text.