SUSCEPTOMETERS FOR FOREIGN BODY DETECTION

摘要

Methods and apparatus for minimizing the effects of temperature drift in a magnetic susceptibility measurement instrument, such as an instrument used i n pre-MRI screening for the presence of ferromagnetic foreign bodies. The magnetic fie ld source and magnetic sensors can be combined into a single, rigid unit. The stabilit y and sensitivity required in high quality magnetic susceptibility measurements ca n be achieved through symmetrical design of the source-sensor unit, minimization of therma l stresses, minimization of temperature variations, use of materials with low thermal expansion coefficients, or through appropriate combinations thereof. Use of patient ey e movement where an eye is being screened, use of a water bag between the patient and t he instrument, or use of telemedicine to facilitate performance of the necessar y computations can also be incorporated.