Patent ID: 8460177

Claim:
A capsule medical device guidance system, comprising: a capsule medical device that includes a magnetic-field responding unit; a magnetic field generator that generates at least a gradient magnetic field in a vertical direction for the magnetic-field responding unit to guide the capsule medical device, the magnetic field generator being capable of changing a gradient distribution of the gradient magnetic field to be generated in the vertical direction; an operation input unit through which operating information for magnetically guiding the capsule medical device is input; a control unit that controls the magnetic field generator according to the operating information input through the operation input unit to guide the capsule medical device, the control unit controlling the magnetic field generator to change a gradient distribution of the gradient magnetic field to be generated in the vertical direction; and a position detector that detects a position of the capsule medical device in the vertical direction based on a gradient distribution of the gradient magnetic field generated by the magnetic field generator, a physical parameter of the capsule medical device, and a physical parameter of a liquid when the capsule medical device starts to move, wherein the control unit sets a magnetic field to be generated by the magnetic field generator based on the position of the capsule magnetic device in the vertical direction detected by the position detector; the control unit controls the magnetic field generator to generate a gradient magnetic field having a gradient in a direction opposite to a direction of a resultant force of buoyancy of the capsule medical device and gravity of the capsule medical device, and controls, after controlling the magnetic field generator to generate a gradient magnetic field for bringing the capsule medical device in contact with a reference surface in an initial state, the magnetic field generator to gradually change the gradient distribution of the gradient magnetic field to be generated such that the capsule medical device is away from a reference surface, the reference surface being at least one of an upper boundary surface and a lower boundary surface of the liquid, and the position detector detects the position of the capsule medical device in the vertical direction based on the gradient distribution of the gradient magnetic field generated by the magnetic field generator when the capsule medical device starts to move, the gradient distribution of the gradient magnetic field having been gradually changed.