Patent ID: 7068867
Filing Date: 2006-06-27
Classification: A61B

Abstract:
1. A system for monitoring a position of an instrument in a subject comprising: a light transmission medium configured to transmit light pulses to a desired region to produce an acoustic signal, wherein the light transmission medium is an optical fiber; at least one ultrasound sensor configured to receive the acoustic signal and to produce a transduced signal from the acoustic signal; a processing unit connected to the at least one ultrasound sensor and configured to locate a source of the acoustic signal using the transduced signal; and a photoacoustic transducer including a photoacoustic material disposed in the desired region to absorb light transmitted by the light transmission medium to produce the acoustic signal, wherein the photoacoustic material is disposed at an end of the optical fiber, and wherein the photoacoustic material is a first photoacoustic material configured to produce a first frequency of sound from absorbed light, the system further comprising a second photoacoustic material configured to produce a second frequency of sound from absorbed light and coupled to the fiber distally from the first material, the first photoacoustic material being disposed and configured to absorb a first portion of light transmitted by the light transmission medium and to pass a second portion of the light transmitted by the light transmission medium.