Electrostatically driven image probe

• US 20080243002A1
• Filed: 01/22/2008
• Published: 10/02/2008
• Est. Priority Date: 01/19/2007
• Status: Active Grant

• Current Assignee: University Health Network
• Original Assignee: University Health Network
• Inventors: Munce, Nigel Robert, Yang, Victor Xiao Dong, Thind, Amandeep Singh, Courtney, Brian
• Granted Patent: US 7,972,272 B2
• Time in Patent Office: Days
• US Class Current: 600/459
• CPC Class Codes: A61B 1/00112 Connection or coupling means
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00183 for variable viewing angles
• CPC Class Codes: A61B 5/0035 adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/5238 for combining image data of patient, e.g. merging several images from different acquisition modes into one image for image registration algorithms G06T7/30
• CPC Class Codes: A61B 8/5292 using additional data, e.g. patient information, image labeling, acquisition parameters
• CPC Class Codes: A61B 8/543 involving acquisition triggered by a physiological signal
• CPC Class Codes: G02B 23/2423 of the distal end
• CPC Class Codes: G02B 6/3604 : Rotary joints allowing relative rotational movement between opposing fibre or fibre bundle ends
• CPC Class Codes: G10K 11/002 : Devices for damping, suppressing, obstructing or conducting sound in acoustic devices G10K1/06 - G10K1/10 take precedence; for electro-mechanical transducers for communication H04R3/002

Abstract

The present invention provides an imaging probe for imaging mammalian tissues and structures using high resolution imaging, including ultrasound and optical coherence tomography. The imaging probe uses electrostatic discharge for actuating a metalized cantilever which holds the end portion of imaging assembly which emits energy in the imaging probe device by holding the cantilever at a potential such that it is neither grounded or charged such that the only electrical path to ground is through a dissipative polymer forming part of the device which is enveloped by a wire or coil held at ground potential. A high voltage electrode attracts the metalized cantilever and the dissipative polymer is used to connect to the cantilever to ground causing the cantilever to move about thereby scanning the region in front of the probe.

Claims

1. Electrostatically driven imaging probe, comprising:

a) an elongate hollow catheter sheath having distal front and back sections and an elongate proximal section and having a diameter suitable to permit insertion of the elongate hollow catheter sheath into bodily lumens and cavities, the distal back section containing an electrically dissipative polymer sealed therein which is wrapped by a metal coil which is connected to ground potential and a trigger circuit;

b) imaging means located in said distal front section for emitting energy and receiving energy reflected back from interior surfaces of said bodily lumens and cavities, said distal front section containing a medium sealed therein which is transparent to said energy emitted by the imaging means, said imaging means being connected to an imaging conduit which extends through a proximal end of the elongate hollow catheter sheath and being connected to an image processing and display system, said imaging conduit being enveloped by metal and a portion of the metal enveloped imaging conduit in the distal front section forming a cantilever; and

c) an elongate electrode located in the elongate hollow catheter sheath having an elongate uninsulated electrode section located in said front distal section, the elongate electrode being connected to a high voltage power supply, wherein in operation when a high voltage is applied to the elongate electrode the cantilever is electrically attracted to the elongate uninsulated electrode section and undergoes deflection towards the elongate uninsulated electrode section and upon contacting the elongate uninsulated electrode section the portion of the metal enveloped imaging conduit in the distal front section acquires an electrical charge from the elongate uninsulated electrode section thereby causing the metal enveloped imaging conduit in the distal front section to be repelled therefrom thereby causing the imaging means to scan the field of view.

2. The electrostatically driven imaging probe according to claim 1 wherein said imaging conduit is an optical fiber and wherein said imaging means includes optical radiation emitted from an end portion of said optical fiber located in said distal front section, said optical fiber being optically coupled to a source of optical radiation through said proximal end of the elongate hollow catheter sheath.

3. The electrostatically driven imaging probe according to claim 1 wherein said imaging means is an ultrasound transducer located in said distal front section for emitting ultrasound signals and detecting reflected ultrasound signals, and wherein said imaging conduit is a coaxial electrical cable electrically connected to said ultrasound transducer at one end and to a power supply through said proximal end of the elongate hollow catheter sheath at another end thereof.

4. The electrostatically driven imaging probe according to claim 2 wherein said imaging means includes focusing optics located in a distal end portion of said distal front section for directing and focusing light emitted from said optical fiber and collecting light reflected back into said distal front section.

5. The electrostatically driven imaging probe according to claim 4 wherein said focusing optics includes a GRIN lens mounted in the distal end portion of said distal front section.

6. The electrostatically driven imaging probe according to claim 4 wherein said focusing optics includes a ball lens attached to end portion of said optical fiber.

7. The electrostatically driven imaging probe according to claim 4 wherein said focusing optics includes an axicon lens attached to the end portion of said optical fiber.

8. The electrostatically driven imaging probe according to claim 3 wherein said ultrasound sensor has a shaped end face for focusing the emitted ultrasound signals.

9. The electrostatic imaging probe according to claim 1 including a ground electrode having an uninsulated section located in one or both of said distal front and back sections connected to said electrical ground potential wherein when said cantilever comes into physical contact with said ground electrode it quickly dissipates all of its acquired charge upon contact and is therefore immediately available to be attracted to the elongate electrode once again so that said cantilever can undergo rapid oscillation.

10. The electrostatically driven imaging probe according to claim 1 including a rotational drive mechanism such that both the distal front and back sections of the electrostatically driven imaging probe are rotated such that the scanning of the cantilever encompasses a two dimensional area in said bodily lumens and cavities in front of said distal front section.

11. The electrostatically driven imaging probe according to claim 1 including at least one additional elongate electrode located in said distal front section connected to said high voltage power supply.

12. The electrostatically driven imaging probe according to claim 11 wherein said high voltage power supply is configured to apply time varying electrical potentials independently to said elongate electrode and to said at least one additional elongate electrode to give a desired scanning motion of the cantilever.

13. The electrostatically driven imaging probe according to claim 12 wherein said high voltage power supply is configured to hold any one of said elongate electrode and said at least one additional elongate electrode at ground potential.

14. The electrostatically driven imaging probe according to claim 12 wherein said at least one additional elongate electrode is three (3) additional elongate electrodes each connected to said high voltage power supply.

15. The electrostatically driven imaging probe according to claim 9 wherein said uninsulated section of said ground electrode is located soley inside said dissipative polymer such that it is not in direct contact with said media in the distal front section.

16. The electrostatically driven imaging probe according to claim 9 wherein said uninsulated section of said ground electrode is located soley inside said distal front section.

17. The electrostatically driven imaging probe according to claim 9 wherein said uninsulated section of said ground electrode is located in both said distal front and back sections

18. The electrostatically driven imaging probe according to claim 1 wherein said dissipative polymer is selected from the group consisting of antistatic molecules blended with polymers, and conductive particles blended with conventional insulating polymers.

19. The electrostatically driven imaging probe according to claim 1 wherein said dissipative polymer is Polyamide/Polyether Block Copolymer (Pebax)™

.

20. The electrostatically driven imaging probe according to claim 1 wherein said medium sealed in said distal front section is selected from the group consisting of fluids and vacuum.

21. The electrostatically driven imaging probe according to claim 20 wherein said medium sealed in said distal front section is a fluid having a pre-selected viscosity for damping oscillatory motion of the cantilever to give pre-selected scanning speeds.

22. Electrostatically driven imaging probe, comprising:

a) an elongate hollow catheter sheath having distal-front and back sections and an elongate proximal section and having a diameter suitable to permit insertion of the elongate hollow catheter sheath into bodily lumens and cavities, the distal back section containing an electrically dissipative polymer sealed therein which is wrapped by a metal coil which is connected to ground potential and a trigger circuit;

b) imaging means located in said distal front section for emitting energy and receiving energy reflected back from interior surfaces of said bodily lumens and cavities, said distal front section containing a medium sealed therein which is transparent to said energy emitted by the imaging means, said imaging means being connected to an imaging conduit which extends through a proximal end of the elongate hollow catheter sheath and being connected to an image processing and display system;

c) a conductive, reflective disc pivotally mounted about a pivot axis in said front distal section and electrically coupled to said electrically dissipative polymer, said reflective member being positioned to receive and reflect said energy from said imaging means, and to receive and reflect said energy reflected back from interior surfaces of said bodily lumens and cavities back to said imaging means;

d) a ground electrode having an uninsulated section located in said distal front section connected to said electrical ground potential; and

e) an elongate electrode located in the elongate hollow catheter sheath having an elongate uninsulated electrode section located in said front distal section, the elongate electrode being connected to a high voltage power supply, wherein in operation when a high voltage is applied to the elongate electrode the conductive, reflective disc is electrically attracted to the elongate uninsulated electrode section causing said conductive, reflective disc to pivot about said pivot axis in one direction causing an outer edge off said conductive, reflective disc to tilt towards said elongate electrode and upon contact with said elongate electrode said conductive, reflective disc acquires charge from said elongate electrode causing it to be repelled thereby resulting in the conductive, reflective disc to pivot towards said ground electrode, and upon contact of said conductive, reflective disk with said ground electrode the conductive, reflective disk loses its charge resulting in its ability to once again be attracted to said electrode.