MULTI-RANGE OPTICAL SENSING

• US 20160081555A1
• Filed: 09/18/2014
• Published: 03/24/2016
• Est. Priority Date: 09/18/2014
• Status: Abandoned Application

• Current Assignee: Biosense Webster Incorporated (Johnson & Johnson)
• Original Assignee: Biosense Webster Incorporated (Johnson & Johnson)
• Inventors: Beeckler, Christopher Thomas, Keyes, Joseph Thomas
• Application Number:
  US14/490,210
• Publication Number:
  US 20160081555A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 1/00009 of image signals during a use of endoscope
• CPC Class Codes: A61B 1/00087 Tools A61B17/00234 takes precedence
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00057 Light
• CPC Class Codes: A61B 2017/00066 intensity
• CPC Class Codes: A61B 2018/00357 Endocardium
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00636 Sensing and controlling the application of energy
• CPC Class Codes: A61B 2018/00982 combined with or comprising means for visual or photographic inspections inside the body, e.g. endoscopes
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 5/0036 including treatment, e.g., using an implantable medical device, ablating, ventilating
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/6852 Catheters

Abstract

The depth of an ablation lesion is assessed using a differential optical response of a catheter with multiple fiberoptic transmitters and receivers at the tip. To detect tissue optical response at shallow depths, closely-spaced transmitter/receiver pairs of optical fibers are used. To detect deeper tissue response, the same or a different transmitter can be used with another receiver that is relatively farther away. The distance between the transmitter and receiver is chosen depending on the desired depth of sensing. Plateauing or peaking of the optical signal during the course of ablation indicates an end point at a selected tissue depth.

Claims

1. An apparatus, comprising:

an insertion tube having a distal portion configured for insertion into proximity with tissue in a body of a patient and containing a lumen comprising;

an electrical conductor for delivering energy to the tissue;

a conductive cap attached to the distal portion of the insertion tube and coupled electrically to the electrical conductor;

a plurality of optical fibers contained within the insertion tube and having terminations at the distal portion, the optical fibers being configurable as optical transmitting fibers to convey optical radiation to the tissue and being configurable as optical receiving fibers to convey reflected optical radiation from the tissue, wherein at the distal portion of the insertion tube, the terminations of the optical fibers are spaced apart at respective distances from one another;

an optical module configured to interrogate the tissue at a predetermined depth by selectively associating the optical transmitting fibers with the optical receiving fibers according to the respective distances therebetween, the optical module operative to emit light along a light path that passes through a selected optical transmitting fiber, reflects from the tissue, and returns to the optical module as reflected light via a selected optical receiving fiber while the electrical conductor is delivering energy to the tissue; and

a processor linked to the optical module for analyzing the reflected light.

2. The apparatus according to claim 1, wherein the optical module is operative for varying an intensity of the light being emitted in the light path.

3. The apparatus according to claim 1, wherein the emitted light in the light path is monochromatic.

4. The apparatus according to claim 3, wherein the emitted light in the light path has a wavelength of 675 nm.

5. The apparatus according to claim 1, wherein the selectively associated optical transmitting fibers and optical receiving fibers are spaced apart by intervals of 0.5-2 mm.

6. The apparatus according to claim 1, wherein analyzing the reflected light comprises determining a time at which the reflected light ceases to vary in intensity by more than a predetermined rate.

7. The apparatus according to claim 1, wherein analyzing the reflected light comprises identifying a time of a peak in intensity in the returning light.

8. The apparatus according to claim 1, wherein analyzing the reflected light comprises determining at respective depths of interrogation times at which variations in a rate of change of a reflected light intensity by more than a predetermined percentage occur.

9. The apparatus according to claim 1, wherein analyzing the reflected light comprises calculating a ratio of two wavelengths and determining a time at which the ratio ceases to vary by more than a predetermined rate.

10. A method, comprising the steps of:

configuring optical fibers contained within a probe as optical transmitting fibers and as optical receiving fibers, wherein terminations of the optical fibers are spaced apart at respective distances from one another;

inserting the probe into a body of a patient;

while delivering energy to a tissue in the body through an ablator of the probe, interrogating the tissue at a predetermined depth by selectively associating one of the optical transmitting fibers with one of the optical receiving fibers according to the respective distances therebetween; and

establishing a light path extending from a light emitter through the one optical transmitting fiber to reflect from the tissue and continuing as reflected light from the tissue through the one optical receiving fiber to a receiver;

transmitting light from the light emitter along the light path; and

analyzing the reflected light reaching the receiver via the one optical receiving fiber.

11. The method according to claim 10, wherein transmitting light comprises varying an intensity of the transmitted light.

12. The method according to claim 10, wherein the light emitter emits monochromatic light.

13. The method according to claim 12, wherein the light emitter emits light having a wavelength of 675 nm.

14. The method according to claim 10, wherein the selectively associated optical transmitting fibers and optical receiving fibers are spaced apart by intervals of 0.5-2 mm.

15. The method according to claim 10, comprising operating a plurality of receiver-transmitter pairs of the optical fibers concurrently at respective wavelengths.

16. The method according to claim 10, wherein analyzing the reflected light comprises determining a time at which the reflected light ceases to vary in intensity by more than a predetermined rate.

17. The method according to claim 10, wherein analyzing the reflected light comprises identifying a time of a peak in intensity in the reflected light.

18. The method according to claim 10, wherein analyzing the reflected light comprises determining at respective depths of interrogation times at which variations in a rate of change of a reflected light intensity by more than a predetermined percentage occur.

19. The method according to claim 10, wherein analyzing the reflected light comprises calculating a ratio of two wavelengths and determining a time at which the ratio ceases to vary by more than a predetermined rate.