Position detection system, medical-device guidance system, and position detection method

A position detection method comprising:

• a magnetic-field generating step of causing a first marker to produce a first alternating magnetic field having a first position-calculating frequency by means of an external power supply;
• an induced-magnetic-field generating step of causing a second marker including a magnetic induction coil to produce an induced magnetic field in response to the first alternating magnetic field;
• a magnetic-field detecting step of detecting a magnetic field at the first position-calculating frequency;
• an extracting step of extracting, from the detected magnetic field, a first detection-magnetic-field component having the first position-calculating frequency and having a phase equal to a phase of the first alternating magnetic field at the first position-calculating frequency;
• and
• a position/orientation analyzing step of calculating at least one of a position and an orientation of the first marker based on the intensity of the extracted first detection-magnetic-field component.

The position detection method according to 9,

• wherein the magnetic-field generating step includes a step of producing a second alternating magnetic field having at least one set of second position-calculating frequencies that are in the proximity of the first position-calculating frequency and are separated by a predetermined frequency with respect to the first position-calculating frequency with the first position-calculating frequency interposed therebetween,
• the induced-magnetic-field generating step includes a step of causing the second marker to produce an induced magnetic field in response to the second alternating magnetic field,
• the magnetic-field detecting step includes a step of detecting a magnetic field at the second position-calculating frequency,
• the extracting step includes a step of extracting, from a detected magnetic field, a difference between intensities of at least one set of second detection-magnetic-field components having the one set of second position-calculating frequencies, and
• the position/orientation analyzing step includes a step of calculating at least one of a position and an orientation of the second marker based on the extracted difference.