POSITION DETECTING DEVICE, MEDICAL DEVICE GUIDANCE SYSTEM, POSITION DETECTING METHOD, AND MEDICAL DEVICE GUIDING METHOD

1 . A position detecting device comprising:

a detected object that includes a circuit with at least one internal coil;

a first magnetic-field generator that includes at least one magnetic-field generating coil for generating a first magnetic field with respect to a detection space of the detected object;

a plurality of detection coils that detect an induced magnetic field generated from the internal coil caused by the first magnetic field;

a magnetic-field-generating-coil switching unit that selects at least one magnetic-field generating coil to be operated from the magnetic-field generating coils in the first magnetic-field generator;

a storage unit that stores predetermined information for selecting at least one magnetic-field generating coil to be operated from the magnetic-field generating coils in the first magnetic-field generator; and

a control unit that controls the magnetic-field-generating-coil switching unit to select the at least one magnetic-field generating coil to be operated among the magnetic-field generating coils in the first magnetic-field generator, based on at least one of a position and a direction of the detected object and based on the predetermined information.

2 . The position detecting device according to claim 1 , wherein the control unit hysteretically selects the magnetic-field generating coil based on the predetermined information.

3 . The position detecting device according to claim 1 , wherein the predetermined information is a continuous operation time of the selected magnetic-field generating coil.

4 . The position detecting device according to claim 1 , wherein the predetermined information is a selection sequence of the magnetic-field generating coil.

5 . The position detecting device according to claim 1 , wherein the predetermined information is information of the first magnetic field generated by the magnetic-field generating coils.

6 . The position detecting device according to claim 1 , further comprising at least one signal generator that outputs an alternating-current signal to the at least one magnetic-field generating coil, wherein

at a time of selecting the magnetic-field generating coil, the control unit stops an output of the signal generator in an active state, and after a predetermined time has passed, disconnects between the magnetic-field generating coil which is in an active state and the magnetic-field-generating-coil switching unit, then after a predetermined time has passed, connects the selected magnetic-field generating coil with the magnetic-field-generating-coil switching unit, and then after a predetermined time has passed, starts an output of the selected signal generator.

7 . The position detecting device according to claim 1 , further comprising at least one signal generator that outputs an alternating-current signal to the at least one magnetic-field generating coil, wherein

at a time of selecting the magnetic-field generating coil, the control unit connects the selected magnetic-field generating coil with the magnetic-field-generating-coil switching unit, and after a predetermined time has passed, starts an output of the selected signal generator, then after a predetermined time has passed, stops an output of the signal generator, which has been in an active state, and then after a predetermined time has passed, disconnects between the magnetic-field generating coil, which has been in an active state, and the magnetic-field-generating-coil switching unit.

8 . The position detecting device according to claim 1 , further comprising a position and direction calculator that calculates a position and a direction of the detected object based on detection results of the detection coils, wherein

the control unit stops calculation of a position and direction by the position and direction calculator during a period where the magnetic-field-generating-coil switching unit is selecting a magnetic-field generating coil.

9 . The position detecting device according to claim 1 , wherein the control unit selects a plurality of detection coils to be operated from the detection coils according to the selected magnetic-field generating coil.

10 . A medical device guidance system comprising:

a medical device that includes a circuit with at least one internal coil and a magnet, the medical device being a detected object;

the position detecting device according to claim 1 ; and

a second magnetic-field generator that generates a second magnetic field for guiding the medical device by operating the magnet.

11 . A position detecting method comprising:

generating a first magnetic field with respect to a detection space of a detected object that includes a circuit with at least one internal coil;

detecting, by a plurality of detection coils, an induced magnetic field generated from the internal coil caused by the first magnetic field;

calculating at least one of a position and a direction of the detected object based on a detection result of the induced magnetic field;

selecting at least one magnetic-field generating coil for generating the first magnetic field, based on at least one of a position and a direction of the detected object and based on predetermined information for selecting at least one magnetic-field generating coil to be operated; and

controlling a magnetic-field-generating-coil switching unit to switch to the selected magnetic-field generating coil.

12 . The position detecting method according to claim 11 , wherein the selecting includes hysteretically selecting the magnetic-field generating coil based on the predetermined information.

13 . The position detecting method according to claim 11 , further comprising selecting at least one signal generator that outputs an alternating-current signal to the at least one magnetic-field generating coil, wherein

the controlling includes:

stopping an output of the signal generator in an active state that outputs an alternating-current signal to the magnetic-field generating coil in an active state;

disconnecting, after a predetermined time has passed, between the magnetic-field generating coil which is in an active state and the magnetic-field-generating-coil switching unit;

then connecting, after a predetermined time has passed, the magnetic-field generating coil selected at the magnetic-field generating-coil selecting step with the magnetic-field-generating-coil switching unit; and

then causing, after a predetermined time has passed, the selected signal generator to start an output of an alternating-current signal.

14 . The position detecting method according to claim 11 , further comprising selecting at least one signal generator that outputs an alternating-current signal to the at least one magnetic-field generating coil, wherein

the controlling includes:

connecting the selected magnetic-field generating coil with the magnetic-field-generating-coil switching unit;

starting, after a predetermined time has passed, an output of the selected signal generator;

then stopping, after a predetermined time has passed, an output of the signal generator which is in an active state; and

then disconnecting, after a predetermined time has passed, between the magnetic-field generating coil which is in an active state and the magnetic-field-generating-coil switching unit.

15 . The position detecting method according to claim 11 , further comprising selecting a plurality of detection coils to be prepared from the detection coils according to the selected magnetic-field generating coil.