Rotating optical catheter tip for optical coherence tomography

Abstract

The present invention relates to a rotating catheter tip for optical coherence tomography based on the use of an optical fiber that does not rotate, that is enclosed in a catheter, which has a tip rotates under the influence of a fluid drive system to redirect light from the fiber to a surrounding vessel and the light reflected or backscattered from the vessel back to the optical fiber.

What is claimed: 
     
         1 . A rotating catheter tip assembly, comprising:
 a housing member having a proximal, a distal end and a central chamber;   a housing cap disposed at the proximal end of the housing member;   at least one inlet port disposed through the housing cap;   a cap member disposed at the distal end of the housing member;   at least one fluid flow port disposed through the cap member;   a turbine disposed within the central chamber; and   a conduit that extends through the housing and the turbine, whereby the turbine rotates relative to the conduit to redirect optical energy from the conduit;   
     
     
         2 . The rotating catheter tip assembly of  claim 1 , further comprising a reflecting material that reflects optical energy emanating from the conduit and the reflecting material coupled with a focusing element to focus the energy from conduit to a target;
 the turbine includes a center axle and a plurality of vane members, wherein the center axle includes a window opening at the distal end, through which the reflecting material reflects the energy emanating from the conduit;   the vane members project radially outward from the center axle and provide a rotating torque to the center axle when a flowing fluid flows against the vane members, thereby causing the center axle to rotate about the conduit;   the central chamber that houses the turbine and includes an inflow and an outflow that define a fluid flow pathway for the flowing fluid, wherein the inflow runs along the turbine from the proximal to distal direction while the outflow exits distally out the at least one fluid flow port disposed through the cap member; and   the at least one inlet port disposed through the housing cap attaches to a plurality of fluid inlet tubes and the fluid inlet tubes are connected to a fluid source.   
     
     
         3 . The rotating catheter tip assembly of  claim 2 , wherein the fluid inlet ports pass through a generally central portion of the housing cap, to transmit fluid to the central chamber and the fluid inlet ports generally align with the turbine. 
     
     
         4 . The rotating catheter tip assembly of  claim 3 , wherein a first central opening disposed through the housing cap includes a concentric recessed seat in which the center axle sits and substantially rotates thereabout without wobbling; the central opening co-axially aligns with longitudinal bore and permits the conduit to be passed there through, whereby the turbine is freely rotatable without rotating the conduit; the axle is co-axially aligned to a second central opening at a distal end of the housing and the second central opening permits axle to rotate about an axis. 
     
     
         5 . The rotating catheter tip assembly of  claim 3 , wherein the cap member includes an inner annular member encircling the second central opening, an outer annular member, a plurality of spacer rib members, and a plurality of spaces, wherein the cap member is concentrically mounted onto the distal end of the axle through the inner annular member; the inner annular member permits the axle to freely rotate thereabout, without wobbling; and the inner annular member and the outer annular member are connected by the spacer rib members and are concentrically spaced apart, wherein the spaces between adjacent pairs of spacer rib members provide the outflow pathways for the fluid flow to pass from the central chamber to the distal end of housing and then out at least one fluid flow port. 
     
     
         6 . The rotating catheter tip assembly of  claim 5 , wherein the focusing element is attached to the conduit as to not rotate. 
     
     
         7 . The rotating catheter tip assembly of  claim 6 , further comprising a space in between the focusing element and the conduit, whereby the focusing element is attached to turbine as to rotate thereby. 
     
     
         8 . The rotating catheter tip assembly of  claim 7 , wherein the vane members have a predetermined curvature along the longitudinal axis of the turbine. 
     
     
         9 . The rotating tip assembly as described in  claim 8 , further comprising a cover having at least a portion which is transparent to the energy which encapsulates the housing and contacts the turbine so no fluid can escape from the housing except through at least one fluid port disposed therethrough. 
     
     
         10 . The rotating tip assembly as described in  claim 9 , wherein the transparent cover is made from any biocompatible transparent plastic. 
     
     
         11 . The rotating tip assembly as described in  claim 10 , wherein the focusing element is chosen from the group consisting of a lens, mirror, lens/mirror combination, prism and liquid crystal. 
     
     
         12 . The rotating tip assembly as described in  claim 11 , wherein the axle includes a wart to redirect energy back to the optical fiber to indicate angular position. 
     
     
         13 . The rotating tip assembly as described in  claim 12 , where the fluid source includes a pump which pumps the fluid from the fluid source. 
     
     
         14 . The rotating tip assembly as described in  claim 13 , wherein the center axle includes a plurality of turbine-like members projecting radially outward from a central longitudinal axis of the axle. 
     
     
         15 . A method for operating a catheter, the catheter comprising a conduit through which optical energy is transmitted; and a first portion through which the conduit extends, the first portion including an inlet tube through which fluid flows; a second portion which provides rotational movement relative to the conduit to redirect the optical energy from the conduit, wherein the second portion comprises a rotating catheter tip assembly, wherein the method comprising the steps of:
 rotating a second portion of a catheter relative to the conduit extending through a first portion of the catheter by flowing a fluid through an inlet tube against the vane members which extend from a rotating center axle of a turbine of the second portion to create a rotating torque on the center axle that causes center axle to rotate about the conduit that extends through the center axle, wherein the fluid flow exits out the distal end of the second portion through at least one fluid port disposed therethrough;   dispersing the fluid through the fluid port in the proximate area of a target to reduce light scattering effects;   redirecting an optical energy transmitted through the conduit to the target from the second portion;   receiving the energy reflected back to the second portion from a target; and   redirecting the reflected energy to the conduit.   
     
     
         16 . The method as described in  claim 15 , wherein the fluid is an artificial blood substitute. 
     
     
         17 . The method as described in  claim 16 , wherein flowing the fluid against vane members which extend from a rotating center axle of a turbine of the second portion to create a rotating torque on the center axle causes the center axle to rotate about the conduit that extends through the center axle. 
     
     
         18 . The method as described in  claim 17 , wherein the conduit does not rotate when the second portion of the catheter rotates. 
     
     
         19 . A rotating catheter tip assembly, comprising:
 a housing member having a proximal end, a distal end, an inner surface and an outer surface;   a cylinder disposed within the housing and having an inner surface that defines a central chamber and an outer surface, wherein a space between the outer surface of the cylinder and the inner surface of the housing defines a peripheral outlet channel;   a housing cap disposed at the proximal end of the housing member;   at least one inlet port disposed through the housing cap, wherein the inlet port is dimensioned for fluid inflow to the central chamber;   a cap member disposed at the distal end of the housing member;   an annular collection channel disposed on the surface of the cap member facing the central chamber,   a plurality of outflow ports disposed through the cap member, wherein the plurality of outflow ports provides fluid communication between the annular collection channel and the peripheral outlet channel such that fluid is collected by the annular collection channel from the central chamber and redirected to peripheral outlet channel by the plurality of outflow ports;   a turbine disposed within the central chamber; and   a conduit that extends through the housing and the turbine, whereby the turbine rotates relative to the conduit to redirect an energy from the conduit.