Patent ID: 7509158
Filing Date: 2009-03-24
Classification: A61B

Abstract:
1. A system comprising: a device that is swallowed, passed through a subject, and includes a magnetic field generator generating a constant magnetic field; and a position transducer that includes a first fixing unit that fixes at least a first magnetic detector to the subject, a second fixing unit that fixes at least second and third magnetic detectors to the subject, the first, second, and third magnetic detectors each detecting an intensity of the magnetic field, position coordinates of the second magnetic detector and the third magnetic detector being fixed with respect to each other, a position fluctuation detector that includes a distance measuring unit and a position fluctuation calculator, the distance measuring unit having a mechanism of detecting a range of variation in a length of the distance measuring unit so as to detect a distance fluctuation between a predetermined point on the first fixing unit and a predetermined point on the second fixing unit, the position fluctuation calculator calculating a fluctuation amount of the positional relation between the first magnetic detector and at least one of the second magnetic detector and the third magnetic detector based on the distance fluctuation detected by the distance measuring unit, a coordinate calibrating unit that calibrates position coordinate of the first magnetic detector based on a detection result by the position fluctuation detector, and a position processor that calculates a position of the device in the subject based on the intensity of the constant magnetic field detected by at least the first, second, and third magnetic detectors and based on at least the position coordinates of the first, second, and third magnetic detectors after the calibration of the position coordinate of the first magnetic detector by the coordinate calibrating unit.