Method and Apparatus for Detecting a Dipole Position Marker

A system for detecting a position within a body, the system comprising:

• a capsule that defines a sealed internal cavity, the capsule having a biocompatible outer surface;
• and
• a dipole positioned in the internal cavity, the capsule and the dipole each shaped such that the dipole is capable of oscillating or rotating within the internal cavity in response to an applied field,
• an electric or magnetic field generator that applies, in a target region of the body, a field that causes the dipole to oscillate or rotate within the capsule;
• a first Doppler transmitter and receiver configured to direct first ultrasound energy at the dipole from a first position outside of the body, receive first ultrasound reflections from the dipole, and process the first ultrasound reflections using Doppler processing to obtain first velocity data;
• a second Doppler transmitter and receiver configured to direct second ultrasound energy at the dipole from a second position outside of the body, receive second ultrasound reflections from the dipole, and process the second ultrasound reflections using Doppler processing to obtain second velocity data;
• a third Doppler transmitter and receiver configured to direct third ultrasound energy at the dipole from a third position outside of the body, receive third ultrasound reflections from the dipole, and process the third ultrasound reflections using Doppler processing to obtain third velocity data;
• and
• a triangulation system that determines the position of the dipole based on the first velocity data, the second velocity data, and the third velocity data.

A method of detecting a position within a body, the method comprising:

• inserting, at a target location within a body, a dipole that is able to oscillate within the body;
• applying an electric or a magnetic field in the vicinity of the dipole, wherein the field and the dipole are configured such that the field causes the dipole to oscillate;
• directing first ultrasound energy at the dipole from a first position outside of the body;
• directing second ultrasound energy at the dipole from a second position outside of the body;
• directing third ultrasound energy at the dipole from a third position outside of the body;
• and
• determining a position of the dipole based on (a) detected reflections of the first ultrasound energy from the dipole, (b) detected reflections of the second ultrasound energy from the dipole, and (c) detected reflections of the third ultrasound energy from the dipole, and (d) knowledge of a relationship between the first position, the second position and the third position.

A method of detecting a position within a body, the method comprising:

• inserting, at a target location within a body, a dipole that is able to oscillate or rotate within the body;
• applying an electric or a magnetic field in the vicinity of the dipole, wherein the field and the dipole are configured such that the field causes the dipole to oscillate or rotate;
• directing first ultrasound energy at the dipole from a first position outside of the body;
• receiving imaging information for the target location;
• and
• determining a position of the dipole based on (a) detected reflections of the first ultrasound energy from the dipole and (b) additional imaging information.