Optical coherence tomography for biological imaging

Patent metadata

Field	Value
Publication number	US-11284839-B2
Application number	US-201916506851-A
Country	US
Kind code	B2
Filing date	Jul 9, 2019
Priority date	May 28, 2009
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

Described herein are catheters for use with Optical Coherence Tomography (OCT) that include an optical fiber core having a first refractive index and an interface medium having a second refractive index, where the first and second refractive indexes are mismatched such that receiving electronics configured to receive optical radiation reflected from the reference interface and the target operate in a total noise range that is within 5 dB of the shot noise limit. These OCT catheters may include a silicon die mirror having a reflective coating that is embedded in the interface medium. The optical fiber can be fixed at just the distal end of the catheter, and may be managed within a handle that is attached to the proximal end of the catheter body, and is configured to allow rotation of the both catheter body and the optical fiber relative to the handle.

First claim

What is claimed is:

1. A catheter system for optical coherence tomography, comprising:
an elongate catheter body;
an optical fiber within the elongate catheter body;
a swept-frequency source of optical radiation configured to provide optical radiation to a core of the optical fiber;
a reference medium comprising a solid transparent adhesive, a distal end of the optical fiber embedded within the reference medium, wherein the reference medium is configured to reflect a first portion of the optical radiation back into the core and to transfer a second portion of the optical radiation to a target;
receiving electronics configured to receive optical radiation from the core that has been reflected from the reference medium and the target; and
a processor configured to generate an image of the target based upon the optical radiation received by the receiving electronics.

2. The catheter system of claim 1 , wherein the solid transparent adhesive is an epoxy.

3. The catheter system of claim 1 , wherein the receiving electronics operate in a total noise range that is within 5 dB of a shot noise limit.

4. The catheter system of claim 1 , further comprising a mirror in an interface medium, the mirror configured to reflect the optical radiation from the optical fiber to the target.

5. The catheter system of claim 1 , further comprising a directional element configured to relay the optical radiation from the swept-frequency source to a distal end of the core.

6. The catheter system of claim 1 , wherein the core has a first refractive index n 1 and the reference medium has a second refractive index n 2 and wherein the first refractive index n 1 and the second refractive index n 2 are mismatched such that:

P
out

P

i
⁢

⁢
n

=

(

n
1

-

n
2

n
1

+

n
2

)

wherein P in is the power of the optical radiation at the distal end of the optical fiber prior to entering an interface medium, and wherein P out is the power of the optical radiation reflected from the reference medium such that the receiving electronics operate in a total noise range that is within 5 dB of a shot noise limit.

7. The catheter system of claim 6 , wherein the first refractive index n 1 and the second refractive index n 2 are mismatched such that:
P det =P out (1− L )

wherein L is the sum of the optical losses from the distal end of a probe to the receiving electronics and P det is the power at the receiving electronics.

8. The catheter system of claim 1 , wherein the elongate catheter body further comprises a cutter.

9. The catheter system of claim 1 , wherein the swept-frequency source is configured to operate at a wavelength between 250 nm-2000 nm.

10. The catheter system of claim 1 , wherein the swept-frequency source is configured to operate at a wavelength between 1300 nm and 1400 nm.

11. The catheter system of claim 1 , wherein the optical fiber is a single mode optical fiber.

12. The catheter system of claim 1 , wherein the solid transparent adhesive is a thermal or UV curable adhesive.

13. The catheter system of claim 1 , wherein the elongate catheter body comprises a side opening therein configured to expose the distal end of the optical fiber embedded within the reference medium, the side opening configured to allow the optical radiation to pass therethrough to the target.

14. The catheter system of claim 13 , wherein the elongate catheter body further comprises a groove radially aligned with the opening, the distal end of the optical fiber positioned within the groove.

15. The catheter system of claim 14 , wherein the reference medium covers the distal end of the optical fiber, the groove, and the opening.

16. The catheter system of claim 1 , wherein the optical fiber is configured to rotate about a longitudinal axis of the elongate catheter body.

17. The catheter system of claim 1 , wherein a proximal end of the optical fiber and the distal end of the optical fiber are fixed relative to the elongate catheter body, and wherein a reminder of the optical fiber is configured to float freely through the elongate catheter body.

18. The catheter system of claim 1 , wherein the image has a resolution of 6-15 microns.

19. The catheter system of claim 1 , wherein the system is configured to image to depths of at least 1-2 mm within the target.

20. The catheter system of claim 1 , wherein the reference medium is configured to provide a return loss of less than 65 dB.

Assignees

• Avinger Inc

Inventors

• Black John F
• Spencer Maegan K
• Zung Michael
• Mcnall Charles W
• Lumabas Evangeline
• Rosenthal Michael H
• Simpson John B

Classifications

• A61B5/6852 Primary

  Catheters · CPC title

• A61B5/0066

  Optical coherence imaging · CPC title