Apparatus and method for nerve ablation in the wall of the gastrointestinal tract
Catheter for real-time evaluation of duodenal ablation, the catheter including an expandable member configured to stretch the duodenal wall and to generate a fixed distance between a center of the catheter and the duodenal wall; a laser transmitting element coupled with the catheter body and configured to transmit a first laser beam and a second laser beam; wherein the first laser beam is configured to cause ablative damage in a region of the duodenal wall as a result of its impingement thereon, and wherein the second laser beam is configured to detect modifications in the region of the duodenal wall resulting from the impingement of the first laser beam thereon.
1. An ablation device comprising:
a catheter comprising an expandable member configured to stretch a wall of a body lumen and to generate a fixed distance between a center of the catheter and the wall;
a laser transmitting element configured to couple to the catheter and to transmit a first laser beam and a second laser beam;
wherein the first laser beam has a first infrared wavelength and is configured to impinge on the wall with a first spot diameter so as to cause ablative damage in a first region of the wall; and wherein the second laser beam has a second wavelength shorter than the first wavelength and in the visible or near-infrared range, and is configured to be transmitted to impinge on a second region of the wall with a second spot diameter;
a sensing arrangement configured to detect backscattered light resulting from the second laser beam impinging on the second region of the wall;
processing circuitry configured to detect an extent of ablative damage in the second region of the wall based on the detected backscattered light and to adjust one or more parameters of the first laser beam based on the detected extent of the ablative damage; and
a rotatable deflective optical element functionally coupled with a laser emitting element and configured to direct the first and second laser beams so as to move the first and second regions in a circumferential trajectory around the wall;
wherein the second spot diameter is larger than the first spot diameter and the second region includes ablative damage illuminated by the second laser beam at a time delay after irradiation by the first laser beam that caused the ablative damage.
2. The device of claim 1 , wherein the laser emitting element comprises a first optical fiber configured to transmit the first laser beam and a second optical fiber configured to transmit the second laser beam, wherein the first and second fibers are spatially off-set.
3. The device of claim 2 , wherein said second laser beam impinges on a given region of the wall at a delay relative to the impingement of the first laser beam, when the deflective element is rotated.
4. The device of claim 1 , wherein the laser transmitting element further comprises a lens configured to deflect the first laser beam.
5. The device of claim 1 , wherein said laser emitting element comprises a double cladded fiber, wherein the first laser beam is delivered through a core of the double cladded fiber and wherein the second beam is delivered through the clad of the double cladded fiber.
6. The device of claim 1 , wherein the laser transmitting element further comprises a dispersive element configured to selectively refract the first and/or second laser beam.
7. An ablation device comprising:
a catheter comprising:
an expandable member configured to stretch a wall of a gastro-intestinal (GI) lumen and to generate a fixed distance between a center of the catheter and the wall;
a laser transmitting element configured to couple to the catheter and to transmit a first laser beam and a second laser beam; wherein the first laser beam has a first infrared wavelength and a first spot diameter and is configured to cause ablative damage in a region of the wall as a result of its impingement thereon; and wherein the second laser beam has a second blue-red wavelength and a second spot diameter, and is configured to be transmitted to a second region of the wall to enable detection of modifications in the region of the wall resulting from the impingement of the first laser beam thereon; and
a rotatable deflective optical element functionally coupled with a laser emitting element and configured to direct the first and/or second laser beam to a region on and/or beneath the wall;
wherein the first and second laser beams are configured to be transmitted towards and/or cause ablative damage to different regions of the wall,
and wherein the second spot diameter is larger than the first spot diameter.
8. The device of claim 1 , wherein the second laser beam is transmitted through a multimode fiber.
9. An ablation method comprising:
inserting a catheter into a body lumen of a subject;
deploying an expandable member delivered by the catheter, thereby stretching a wall of the body lumen and generating a fixed distance between a center of the catheter and the wall;
transmitting a first laser beam in a direction essentially perpendicular to a longitudinal axis of the catheter, towards the wall, wherein the first laser beam has a first infrared wavelength and impinges on the wall with a first spot diameter so as to cause ablative damage in a first region of the wall;
transmitting a second laser beam essentially perpendicularly to the longitudinal axis of the catheter, wherein the second laser beam has a second wavelength shorter than the first wavelength and in the visible or near-infrared range, and impinges on the wall with a second spot diameter at a second region;
employing a sensor arrangement to generate an output indicative of backscattered light resulting from the second laser beam impinging on the second region of the wall;
employing processing circuitry to process the output of the sensor arrangement to detect an extent of ablative damage in the second region of the wall and to adjust one or more parameters of the first laser beam based on the detected extent of the ablative damage;
wherein transmitting of the first and second laser beams is performed so as to move the first and second regions in a circumferential trajectory around the wall,
and wherein the second spot diameter is larger than the first spot diameter and the second region includes ablative damage illuminated by the second laser beam at a time delay after irradiation by the first laser beam that caused the ablative damage.
10. The method of claim 9 , wherein the second laser beam is transmitted at a delay relative to the transmission of the first laser beam.
11. The method of claim 9 , wherein the first and second laser beams are transmitted simultaneously towards the different regions of the wall.
12. The device of claim 1 , wherein the second region is non-overlapping with the first laser spot and configured to follow behind the first laser spot along the circumferential trajectory.
13. The device of claim 1 , wherein the time delay is at least a tenth of a second.
14. The method of claim 9 , wherein the time delay is at least a tenth of a second.