| 摘要 |
A method and apparatus for sequentially exposing a region of a patient to a low level DC magnetic field, first without movement of the region to null the sensing apparatus, then with movement of the region to detect synchronous changes in the detected signal, indicative of a ferromagnetic foreign body in the region. The nulling and signal detection can take place at a plurality of test zone set points at increasing magnitudes of the applied magnetic field. The sensing apparatus can be nulled at each test zone set point prior to introduction of the patient.
|
