| 摘要 |
PCT No. PCT/EP96/03857 Sec. 371 Date Feb. 9, 1998 Sec. 102(e) Date Feb. 9, 1998 PCT Filed Sep. 3, 1996 PCT Pub. No. WO97/09640 PCT Pub. Date Mar. 13, 1997The invention concerns a method and an arrangement for determining the position of a marker in an organic cavity, in particular for establishing local passage speeds within the framework of the medical diagnosis of the stomach-bowel tract. The object of the invention is to provide a solution which ensures position-determining accuracy of greater than 1 cm in all three co-ordinate directions and permits position-determining times of 10 seconds and less in each case. According to the invention, this object is achieved in that at least one coil is acted upon in a time interval in a pulsed manner by current whose sign changes in each case between two current pulses, when the primary magnetic field, of the coil, produced thereby has died out to sufficiently low values. The secondary magnetic field generated by a marker is measured separately at least once by anisotropic magnetic field sensors parallel and perpendicular to the coil axis. The coil arrangement is displaced relative to the marker until the magnetic field sensors used to determine the radial component of the secondary magnetic field of the marker supply a zero signal and the associated position of the coil axis and the associated measured values supplied by the magnetic field sensors used to detect the secondary magnetic field component of the marker, which component runs parallel to the coil axis, are stored and fed to a display.
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