Apparatus and method for nerve ablation in the wall of the digestive tract - Patent Application 20070229933

Abstract

To provide an apparatus and method for providing feedback on nerve ablation in the wall of a gastrointestinal tract GI.SOLUTION: There is provided a 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.SELECTED DRAWING: Figure 5A

Description

[Technical field]

[0001] The present disclosure relates generally to devices and methods for providing feedback to nerve ablation in the wall of the gastrointestinal (GI) tract. [Background technology]

[0002] Obesity is believed to be one of the main causes of type 2 diabetes, especially in people genetically predisposed to the disease. Obesity is often treated by performing bariatric surgery procedures (also known as weight loss surgery) on the digestive tract of obese patients to reduce body weight. Multiple clinical trials and reports have shown that in addition to weight loss, certain bariatric surgery procedures can contribute to the remission or improved disease management of type 2 diabetes, as well as reducing insulin resistance. This is especially true in the case of certain bariatric procedures that bypass the proximal gastrointestinal (GI) tract, such as Roux-en-Y gastric bypass (RYGB), duodenal-jejunal bypass (DJB) surgery, and gastrojejunal bypass (GJB) surgery, all of which aim to bypass the duodenum. Unfortunately, bariatric surgery is associated with high risks and high costs, making it a suboptimal solution for the management of the majority of non-obese patients with T2D, estimated at hundreds of millions worldwide. As a result, bariatric surgery is not typically considered a disease management tool for the majority of T2D patients.

[0003] Attempts to achieve similar results to bariatric surgery include the use of minimally invasive devices such as those inserted intraluminally, including staplers to reduce stomach size, intragastric balloons, implantation of electrical stimulators to intervene in stomach function (gastric electrical stimulation), sleeves that bypass the duodenum (e.g., EndoBarrier®, GI Dynamics™, and radiofrequency (RF) ablation), applied to the surface of the organ with non-penetrating electrodes targeting the duodenal mucosa, or by ablation of the area around the pyloric sphincter. However, these methods suffer from certain inherent limitations, such as association with adverse events and unwarranted side effects (e.g., vomiting, nausea, abdominal pain, mucosal laceration, bleeding, migration, and obstruction), the need for early device removal, complications, and limited or even absent efficacy.

[0004] Laser ablation has been proposed as a method to selectively block part of the neural activity in the small intestine, preferably the duodenum of a subject. However, creating a neural lesion in the intestinal wall is a challenge, because the wall is very thin and the thickness, as well as the folds and secretory components, are subject to high inter- and intra-patient variability. Damage or perforation of the wall can be dangerous. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore desirable to provide a means for monitoring, controlling and / or evaluating the efficacy of the ablation process during a procedure. [Means for solving the problem]

[0006] The present disclosure relates to methods, devices and systems for monitoring, controlling and / or evaluating the efficiency of the ablation process during a procedure.

[0007] Laser ablation selectively targets neural activity in the small intestine, preferably the duodenum of a subject. Ablation has been proposed as an efficient procedure to effectively block the neurohormonal and / or other signals triggered by the passage of food through the gastrointestinal (GI) tract, and thus the subject's sense of satiety.

[0008] However, neuropathies within the wall of the intestine are challenging because the wall is very thin, folded, and subject to high inter- and intra-patient variability. At the same time, injury and / or perforation of the intestinal wall can be dangerous.

[0009] Advantageously, the devices, methods, and systems disclosed herein can monitor and / or assess the extent of the impact caused to the duodenal wall in real time and, optionally, adjust ablation parameters accordingly.

[0010] The device may advantageously include an expandable member, such as a non-compliant balloon, configured to stretch the duodenal wall, thereby ensuring that the inner diameter of the duodenum is essentially constant along the section stretched and / or associated with the balloon. This advantageously allows a catheter inserted into the duodenum to be positioned at the center of the duodenum in the area designated for treatment, thereby ensuring that circumferential ablation is with essentially the same dose of laser energy regardless of the orientation of the laser. The described mechanisms for keeping ablation elements concentric in a "moving, dynamic" circular organ such as the intestine can be performed with a laser or any other non-direct energy emitting radiator, such as ultrasound or electromagnetic radiation. Most such methods have effects on tissue that are directly correlated with their linear velocity on the tissue, rather than angular velocity, and are therefore particularly beneficial for laser ablation.

[0011] The device further includes a laser transmission element configured to transmit a first laser radiation to a target region of the duodenal wall, thereby causing ablation and / or deformation thereof, and a second laser radiation configured to enable scanning of the tissue region, thereby obtaining feedback indicative of the extent of an effect caused to the tissue as a result of the first ablative laser radiation impinging on the tissue, advantageously allowing real-time assessment of deformation in the treated tissue.

[0012] According to some embodiments, the second laser beam may be delayed relative to the first laser beam with respect to essentially the same target area, which advantageously allows photothermal and / or photochemical processes to occur prior to monitoring by the feedback beam.

[0013] Additionally, according to some embodiments, the spot diameter of the first ablation radiation may be smaller than the spot diameter of the second evaluation radiation, which advantageously allows for the evaluation of "collateral" effects caused in tissue that is not directly ablated, but is affected by its proximity to the directly ablated tissue.

[0014] According to some embodiments, an apparatus for evaluating duodenal ablation in real time comprises a catheter, the catheter comprising an expandable member configured to stretch the duodenal wall and create a fixed distance between a center of the catheter and the duodenal wall; a laser transmission element coupled to the catheter body and configured to transmit a first laser beam and a second laser beam, the first laser beam having a first wavelength and a first spot diameter and configured to cause an ablation lesion in a region of the duodenal wall as a result of its impact against the region, and the second laser beam having a second wavelength and a second spot diameter and configured to detect deformation in a region of the duodenal wall resulting from the impact of the first laser beam against the region; and a laser transmission element coupled to the catheter body and configured to transmit a first laser beam and a second laser beam, the first laser beam having a first wavelength and a first spot diameter and configured to cause an ablation lesion in a region of the duodenal wall as a result of its impact against the region, and a laser emission and a deflection optical element operatively coupled to the element and configured to direct the laser beam to areas above and / or below the duodenal wall.

[0015] According to some embodiments, the laser emitter can include a first optical fiber configured to transmit the first laser beam and a second optical fiber configured to transmit the second laser beam, According to some embodiments, the first and second fibers are spatially offset.

[0016] According to some embodiments, the laser transmission element can further include a lens configured to deflect the first laser beam such that the first and second laser beams are transmitted toward different target areas of the duodenal wall and / or when the deflection optical element is rotated, the second laser beam impinges on a given target area later than the impingement of the first laser beam on the same area.

[0017] According to some embodiments, the laser emitter may include or be a double clad fiber. According to some embodiments, the first laser beam is transmitted through a core of the double clad fiber and the second beam is transmitted through a clad of the double clad fiber.

[0018] According to some embodiments, the laser transmission element can further include a dispersive element configured to selectively refract the first and / or second laser beams such that the first and second laser beams are transmitted toward different target regions of the duodenal wall and / or when the deflection optics is rotated, the second laser beam impinges on a given target region later than the impingement of the first laser beam on that target region.

[0019] According to some embodiments, the first wavelength is 1550 nm or 1567 nm. According to some embodiments, the second wavelength is 980 nm.

[0020] According to some embodiments, the second spot diameter is larger than the first spot diameter, thereby enabling assessment of ablation damage caused to tissue directly and indirectly affected by the first laser beam.

[0021] According to some embodiments, the device may further include processing circuitry configured to assess the extent of the impact on a region of the duodenal wall based on the deformation detected within the region.

[0022] According to some embodiments, a method for evaluating duodenal ablation in real time includes inserting a catheter into a subject's duodenum; deploying an expandable member delivered by the catheter, thereby stretching the duodenal wall and creating a fixed distance between a center of the catheter and the duodenal wall; and transmitting a first laser beam toward the duodenal wall in a direction essentially perpendicular to a longitudinal axis of the catheter, the first laser beam having a first wavelength and a first spot diameter, the first laser beam having a first wavelength and a first spot diameter and configured to transmit the first laser beam toward the duodenal wall in a direction essentially perpendicular to a longitudinal axis of the catheter, the first laser beam having a first wavelength and a first spot diameter and configured to transmit the first laser beam toward the duodenal wall in a region of the duodenal wall. a first laser beam configured to cause an ablation lesion as a result of its impact on a region of the duodenal wall; transmitting a second laser beam essentially perpendicular to a longitudinal axis of the catheter, the second laser beam having a second wavelength and a second spot diameter, and configured to detect deformation within the region of the duodenal wall resulting from the impact of the first laser beam on the region; and assessing a degree of effect on the region of the duodenal wall based on the detected deformation within the region.

[0023] According to some embodiments, the first wavelength is in the range of 1450 to 1600 nm. According to some embodiments, the first wavelength is 1550 nm. According to some embodiments, the second wavelength is 980 nm.

[0024] According to some embodiments, the second spot diameter is larger than the first spot diameter, thereby enabling assessment of ablation damage caused to tissue directly and indirectly affected by the first laser beam.

[0025] According to some embodiments, the expandable member may include or be a non-compliant balloon.

[0026] According to some embodiments, the second laser beam is delivered to a region of the duodenal wall at a delay relative to the delivery of the first laser beam to that same region.

[0027] According to some embodiments, the delay is in the range of 0.1 to 10 seconds.

[0028] According to some embodiments, the first and second laser beams are simultaneously transmitted toward different target regions of the duodenal wall.

[0029] According to some embodiments, the method may further include rotating the deflection optics such that the first and / or second laser beams are deflected in an essentially circumferential pattern toward the duodenal wall.

[0030] According to some embodiments, assessing the extent of impact on an area of ​​the duodenal wall can include determining the depth and / or width of the resection lesion.

[0031] According to some embodiments, the method may further include adjusting parameters for the first laser beam based on an assessment of the extent of the impact on the region of the duodenal wall detected by the second laser beam.

[0032] Certain embodiments of the present disclosure may include some, all, or none of the above advantages. From the figures, descriptions, and claims contained herein, one or more technical advantages may be readily apparent to those skilled in the art. Furthermore, although certain advantages are listed above, various embodiments may include all, some, or none of the listed advantages.

[0033] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description. [Brief description of the drawings]

[0034] Examples illustrating the embodiments are described below with reference to the accompanying drawings. In the figures, identical structures, elements or parts that appear in more than one figure are usually labeled with the same numerals in all figures in which they appear. Alternatively, elements or parts that appear in more than one figure may be labeled with different numerals in the different figures in which they appear. Dimensions of components and features shown in the figures are usually selected for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below. [Figure 1] FIG. 1 is a schematic diagram of an optical system for ablation of duodenal tissue with real-time ablation feedback, according to some embodiments. [Diagram 2] 1A-1C show two optional optical concepts for spatial separation of an ablation beam and a feedback beam configured to evaluate the impact of the ablation beam, according to some embodiments. [Diagram 3] FIG. 1 illustrates an example of lateral beam separation for a target region within the duodenal wall, according to some embodiments. [Figure 4] 1 is a schematic diagram of the difference in spot diameter of an ablation laser beam and an evaluation laser beam according to some embodiments. [Figure 5A]FIG. 13 is a schematic diagram of a setup utilizing two separate optical fibers to deliver the ablation beam and the feedback beam, according to some embodiments. [Figure 5B] 1 is a schematic diagram of a setup utilizing a combiner (e.g., a double-clad optical fiber) according to some embodiments. [Figure 6] 1 is a schematic diagram of a balloon configured to stretch and / or expand the duodenum to a predetermined diameter or range of diameters, according to some embodiments. [Figure 7] FIG. 1 is a schematic diagram of a balloon configured to stretch and / or expand the duodenum to a predetermined diameter or range of diameters, having multiple balloon segments, according to some embodiments. [Figure 8A] 1 is a schematic diagram of a balloon in a folded configuration with multiple balloon sections within the duodenal lumen, according to some embodiments. [Figure 8B] 1 is a schematic diagram of a balloon in an expanded / inflated configuration with multiple balloon sections within the duodenal lumen, according to some embodiments. [Figure 9] FIG. 1 is a schematic diagram of a balloon configured to stretch and / or expand the duodenum to a predetermined diameter or range of diameters, according to some embodiments, the balloon including a support member configured to stabilize a laser transmission element within the center of the balloon. [Figure 10] FIG. 5B illustrates the correlation obtained between ablation power and detected feedback signal power using the optical setup shown in FIG. 5A. [Figure 11A] FIG. 13 shows results obtained from offline evaluation of duodenal ablation using a laser emitting a feedback beam. [Figure 11B] FIG. 13 shows results from offline assessment of duodenal ablation using visual observation. [Figure 12] FIG. 1 shows ablation power versus time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] In the following description, various aspects of the present disclosure are described. For the purpose of explanation, specific configurations and details are described to provide a thorough understanding of various aspects of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without the specific details set forth herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the present disclosure.

[0036] According to some embodiments, a device is provided for real-time assessment of duodenal ablation (or other lumen within the GI or pulmonary tract), the device including a catheter including an expandable member configured to stretch the duodenal wall and create a fixed distance between a center of the catheter and the duodenal wall, and a laser transmission element coupled to the catheter body and configured to transmit a first laser beam and a second laser beam.

[0037] As used herein, the term "duodenum" refers to a portion of the small intestine of a vertebrate digestive tract located between the stomach and the jejunum. According to some embodiments, the duodenum includes the pylorus of the stomach. The duodenum includes a lumen and a duodenal wall surrounding the lumen. The duodenal wall includes the following layers from the lumen outward: the mucosal villi layer, the submucosa (including the submucosal plexus, the circular muscle layer, and the myenteric plexus), the longitudinal muscle layer, and the peritoneal / mesenteric layer. The combination of the circular muscle layer and the longitudinal muscle layer may be referred to herein as the muscular layer.

[0038] As used herein, the terms "submucosal plexus" and "Meissner's plexus" may be used interchangeably and refer to a plexus present in the submucosa of the duodenal wall. Without being bound by any theory, the submucosal plexus transmits nerve signals within the duodenum to nerves outside the duodenum, such as the vagus nerve, duodenal ganglion, sympathetic nerves, and parasympathetic nerves. The submucosal plexus primarily contains sensory neurons that transmit nerve signals derived from chemical and / or mechanical sensors within the duodenum that are activated by the passage of food through the duodenum.

[0039] According to some embodiments, the target area is an area in the duodenal wall that contains sensory neurons. According to some embodiments, the target area includes at least a portion of neurons in an area selected from the group consisting of the enteric plexus, the submucosal plexus, the duodenal branch of the vagus nerve, the sympathetic nerves innervating the duodenal wall, the parasympathetic nerves innervating the duodenal wall, the VAN array in the duodenal wall, and combinations thereof. Each possibility represents a separate embodiment of the present disclosure.

[0040] As used herein, the term "catheter" refers to a catheter configured to be introduced into the lumen of the duodenum. According to some embodiments, the catheter is configured to be introduced into the lumen of the duodenum through the mouth of a subject. According to some embodiments, the catheter is configured to be introduced through the colon. According to some embodiments, the catheter includes an intraluminal duodenal catheter. According to some embodiments, the catheter is an intraluminal duodenal catheter. According to some embodiments, the catheter is a laser emitting catheter. According to some embodiments, a laser element is included, and in some cases disposed, within the catheter.

[0041] According to some embodiments, the first laser beam may be an ablative laser beam, ie, a laser beam configured to ablate tissue upon which it impinges.

[0042] According to some embodiments, the second laser beam may be an evaluation and / or feedback laser beam, i.e. a laser beam configured to enable detection of deformations in tissue caused by the ablation laser beam.

[0043] According to some embodiments, the second laser beam can optionally scan perpendicularly to the ablation line with different power densities. According to some embodiments, the second laser beam can scan back and forth across the ablation line, possibly linearly and / or spirally. According to some embodiments, the amount of backscattered second laser beam is optionally linearly correlated with the degree of ablation and / or deformation caused to the tissue. According to some embodiments, the laser transmission element includes a sensor configured to detect and / or absorb the backscattered light of the first and / or second laser beam.

[0044] As used herein, the term "ablation" can refer to affecting tissue by vaporizing, chipping, cutting, impacting, denervating, deforming, damaging, detaching or other erosive process or combination of processes, or alternatively, disrupting at least a portion of neurons in a target area. Each possibility is a separate embodiment. According to some embodiments, ablation can refer to a process in which damage is caused to duodenal tissue and / or sensory nerves in the duodenal tissue by transmitting laser radiation. According to some embodiments, ablation includes thermal damage. According to some embodiments, ablation includes mechanical damage. According to some embodiments, the ablative laser radiation can be configured to heat the target area to at least 45-75°C or significantly higher temperatures to induce more significant damage when exposure is very brief. According to some embodiments, ablation ... The present invention can affect the neurohormonal and / or other signals transmitted thereby affecting the subject's feelings of satiety and / or hunger and / or hormone secretion.

[0045] According to some embodiments, the first and / or second laser radiation may be pulsed laser radiation. According to some embodiments, the first ablative laser radiation may be focused on a target area that includes sensory neurons. According to some embodiments, tissue surrounding the target area remains functional.

[0046] According to some embodiments, the first and / or second laser beams may be configured to be transmitted in a direction essentially perpendicular to the longitudinal axis of the catheter, for example, using a prism, mirror, or other suitable deflection element. According to some embodiments, a deflection element operatively coupled to the laser emitter may be configured to direct the laser beam to an area above and / or below the duodenal wall. According to some embodiments, the deflection element (e.g., a prism or mirror) may be rotatable to cause circumferential ablation. As used herein, the terms "circumferential ablation" or "ablation along a circumferential trajectory" may be used interchangeably and may refer to ablation provided around the duodenal wall. According to some embodiments, the circumferential ablation may be circular, i.e., where the laser beam rotates 360 degrees without moving the catheter and / or the laser emitter. According to some embodiments, the circumferential ablation may be helical, i.e., where the laser beam rotates simultaneously with the forward (or backward) movement of the catheter and / or the laser emitter.

[0047] According to some embodiments, the deflection element can deflect the first and / or second laser radiation at a 90 degree angle from the longitudinal axis of the catheter. According to some embodiments, the deflection element deflects the first and / or second laser radiation through one or more openings in the catheter. According to some embodiments, the deflection element can be disposed in a distal head of the catheter. According to some embodiments, the deflection element can be associated with or be an integral part of the laser transmission element. According to some embodiments, the deflection element can be rotatable. According to some embodiments, the deflection optical element can direct the laser radiation to multiple target regions along a circular trajectory within or in contact with the duodenal wall. Each possibility represents a separate embodiment of the present disclosure. According to some embodiments, the deflection element can be or include a prism, or optionally a rotatable prism. According to some embodiments, the deflection element can be or include a beam splitter prism. According to some embodiments, the device can further include at least one lens element. According to some embodiments, the lens element is or includes a corrective lens configured to correct aberrations.

[0048] According to some embodiments, the deflecting optics / elements may be selected from the group consisting of wide angle lenses, dove prisms, inverting or "K" prisms, delta or Pechan prisms, dispersing prisms, reflecting prisms, beam splitting prisms, deflecting prisms, triangular prisms, trapezoidal prisms, Glan-Taylor or Glan-Laser prisms, high power laser light right angle prisms, retroreflectors and combinations thereof. Each possibility is a separate embodiment. According to some embodiments, the prism is a low loss deflecting prism. According to some embodiments, the dispersing prism is a triangular prism, a Pellin-Broca prism, an Abbe prism, or a compound prism. According to some embodiments, the optical element may be a wide angle lens system capable of correcting fθ distortion or fsin(θ) distortion. According to some embodiments, the system includes a focusing element placed in front of an optionally rotatable optical element, with a focal length long enough to allow focusing on a target. Further includes:

[0049] According to some embodiments, the first ablation laser radiation is a pulsed laser radiation configured to initiate nonlinear energy absorption and interaction with tissue. Without wishing to be bound by any theory or mechanism, the short-pulse focused laser radiation directed at tissue can result in nonlinear interaction with tissue, whereby plasma formation and / or photoablation occurs only at sites in tissue with a high enough energy flux that the energy peak in a given area exceeds a predetermined threshold. According to some embodiments, photoablation in the presence of a high enough peak power in the focal area can involve some absorption of the laser beam by adjacent tissue. A non-limiting example of a laser that can be used to generate such laser radiation is a micro Q-switched Nd:YAG laser, such as, but not limited to, the one manufactured by Kigre (MK-367), which is very compact and generates a beam that exceeds the ablation threshold when sufficiently focused. Alternatively, standard flash-pumped Q-switched lasers (including those that are self-Q-switched), high repetition rate solid-state diode-pumped Nd:YAG lasers, fiber lasers that use small spots to achieve high enough peak power to cause damage, or any combination thereof. Each possibility represents a separate embodiment. Other non-limiting examples include CW, quasi-CW or Q-switched lasers, such as CW lasers in the 1550-1570 nm range. Suitable lasers can be, for example, 532 nm double YAG, or 980 nm or 808 nm laser diodes, lasers in the 1500 nm range, or 2 micron holmium / thulium lasers.

[0050] According to some embodiments, the ablation beam can have a wavelength in the range of 1300-1400 nm, 1450-1600 nm, 1530-1590 nm, 1550-1570 nm, 980-1064 nm, or 1850-1950 nm. As a non-limiting example, the ablation beam can have a wavelength of 1550 nm. As another non-limiting example, the ablation beam can have a wavelength of 1064 nm. As another non-limiting example, the ablation beam can have a wavelength of 1067 nm. As another non-limiting example, the ablation beam can have a wavelength of 980 nm.

[0051] According to some embodiments, the feedback beam can have a wavelength that is the same or different from that of the ablation beam. According to some embodiments, the feedback beam can have a wavelength of 532 nm, 780 nm, 808 nm, 980 nm, 1310 nm, 635 nm, 1550-1570 nm, and can use a green laser in CW or modulated mode, or a blue LED. As a non-limiting example, the feedback beam can have a wavelength of 980 nm with a power of less than 1 watt in CW mode or a modulation of 21-990 Hz. The ablation beam can have a wavelength of 1550-1567 nm with a power in the range of 0.1-30 watts or 3-30 watts in CW mode, or a modulation of 5-100 Hz.

[0052] According to some embodiments, the feedback can be based on back reflection and / or scattering of light from the ablated tissue. According to some embodiments, the feedback beam can scan over the ablation line generated by the rotating ablation laser beam. According to some embodiments, the feedback beam allows for evaluating the width of the ablation line, the amplitude of the peak of the ablation line, the ablation area, or any combination thereof. Each possibility is a separate embodiment.

[0053] According to some embodiments, the same laser may be used for both ablation and feedback, for example the 1550-1567 nm lasers listed above.

[0054] According to some embodiments, different lasers may be used for ablation and feedback. According to some embodiments, ablation may be performed using a single mode laser (SM) while feedback may be performed using a multimode laser (MM). According to some embodiments, the ablation fiber is single mode while feedback is based on a multimode fiber configured to provide high focal depth for ablation and high collection throughput for imaging / feedback. According to some embodiments, the SM ablation fiber may be coupled to a core fiber with a controlled / limited increase in beam diameter, i.e., from about 10 microns to 50-200 microns, which reduces the beam divergence. According to some embodiments, M-squared increases by no more than 3-5 times.

[0055] According to some embodiments, the laser emitter can include two or more optical fibers, i.e., a first optical fiber configured to transmit a first ablation laser beam and a second optical fiber configured to transmit a second evaluation laser beam. According to some embodiments, the fiber pairs can be assembled, for example, in a V-groove, assembled separately, or fused to a lens to obtain a target displacement that correlates with a required displacement in the imaging plane, as described further below.

[0056] According to some embodiments, the fiber configured to transmit the first ablation radiation may have a smaller core than the fiber used for the feedback radiation, such that the spot diameter of the feedback radiation on the tissue is larger than the spot diameter of the ablation beam, as further detailed herein.

[0057] According to some embodiments, the fiber configured to transmit both the first ablation radiation and the second evaluation radiation may have a smaller core than the fiber used to read or sense the feedback radiation.

[0058] According to some embodiments, the laser emitter can include a double-clad fiber configured to transmit a first ablation laser beam through the core and a second evaluation laser beam through the cladding.

[0059] According to some embodiments, the laser emitter can include a double clad fiber configured to send a first ablation laser beam and a second evaluation beam through the core and sense / read scattered back reflections of the evaluation laser beams through the cladding.

[0060] According to some embodiments, the fiber configured to transmit the ablation radiation may have a smaller core than the fiber used to read the feedback of the radiation.

[0061] As used herein, the term "real-time assessment" refers to assessing effects caused to tissue, such as duodenal tissue, as a result of the delivery of ablative radiation performed during an ablation procedure. According to some embodiments, the real-time assessment may be performed simultaneously with the ablation, for example by simultaneously delivering ablative radiation and evaluation laser radiation toward the target area. According to some embodiments, the real-time assessment may be sequential, as further detailed herein.

[0062] According to some embodiments, the real-time assessment may include post-ablation assessment. This can be done by sensing the light scattered in one direction.

[0063] According to some embodiments, the feedback beam can monitor and / or identify at least one parameter related to the ablation of duodenal tissue. According to some embodiments, the feedback beam can monitor and / or identify two or more parameters related to the ablation of duodenal tissue, such as 2, 3, 4, 5, 10 or more parameters. Each possibility is a separate embodiment. Non-limiting examples of suitable parameters that may be evaluated, monitored and / or identified by the feedback beam include: effectiveness of the ablation, abnormalities and / or malfunctions in the ablation process (e.g., improper expansion of the expandable member, improper termination of the laser treatment, beam rotation failure, etc.), beam rotation speed, diameter of the expanded portion (e.g., by measuring the diameter of the expandable member once expanded), identification of previous ablated sections, such as to align repositioning of the expandable member for a repeat intervention, identification of undesirable tissue such as, but not limited to, the papilla, or any other suitable parameter or combination of parameters. Each possibility is a separate embodiment.

[0064] Additionally or alternatively, the evaluation of the ablation may include collection of back-reflected and / or scattered light resulting from the ablation laser beam itself, thus eliminating the need for additional lasers and / or optical fibers. According to some embodiments, the feedback may include operating the laser transmission element in a first ablation mode and then operating the laser transmission element in a second evaluation mode configured to detect and / or collect the back-reflected and / or scattered radiation. According to some embodiments, the feedback may be based on the amplitude and / or phase shift and / or noise spectrum of the reflected beam and / or noise within a preset frequency range and / or deviation from a preset range associated with the reflection / scattering.

[0065] According to some embodiments, the laser beam can be used to provide feedback regarding the effects achieved using other ablation modalities such as, but not limited to, radio frequency (RF) ablation, microwave ablation, ultrasound ablation, thermal ablation, etc. Each possibility is a separate embodiment.

[0066] According to some embodiments, the first ablation laser beam can have the same or a different spot diameter on the tissue compared to the second evaluation laser beam.

[0067] According to some embodiments, the spot diameter of the second evaluation laser beam may be larger than the spot diameter of the first ablation laser beam. For example, the first laser beam may have a spot diameter in the range of 10-500 microns, 20-400 microns, 100-400 microns, 100-300 microns, 20-200 microns, or any other range of spot diameters in the range of 10-500 microns. Each possibility is a separate embodiment. On the other hand, the second laser beam may have a spot diameter in the range of, for example, 400-1500 microns, 500-1000 microns, 500-750 microns, or any other range of spot diameters in the range of 400-1500 microns. Each possibility is a separate embodiment. According to some embodiments, the second evaluation laser beam may be 1.5-100 times larger, 1.5-50 times larger, or 2-25 times larger than the spot diameter of the first ablation laser beam. Each possibility is a separate embodiment. Such differences in spot size can enable evaluation of tissue adjacent to tissue directly affected by the ablation, also referred to herein as collaterally affected tissue. As discussed further below, having a larger spot diameter can require the evaluation beam to be delayed relative to the ablation beam.

[0068] According to some embodiments, the spot diameter of the second evaluation laser beam may be smaller than the spot diameter of the first ablation laser beam, which may serve to ensure that the signal detected by the evaluation laser beam is not distorted, attenuated, or otherwise affected by undamaged tissue or by tissue in which photothermal and / or photochemical processes have not yet occurred.

[0069] According to some embodiments, the laser emitter may be configured to transmit a delayed second evaluation laser beam, the purpose of this embodiment being to allow photothermal and / or photochemical processes to occur prior to monitoring by the feedback beam, which may be particularly important when the evaluation laser beam has a larger spot size than the ablation laser beam.

[0070] According to some embodiments, the laser emitter may be configured to transmit the second evaluation laser beam with a delay of, for example, 0.1-1.0 seconds, 0.1-0.5 seconds, 0.25-0.75 seconds, 0.5-1.0 seconds, or any other suitable delay within a range of 0.1-100.0 seconds, each possibility being a separate embodiment.

[0071] According to some embodiments, the delay can be caused by temporarily separating the transmission of the first and second laser beams, for example, the transmission of the second evaluation laser beam can be delayed by 0.1 seconds relative to the first ablation laser beam.

[0072] According to some embodiments, the delay can be induced by spatially separating the first (ablative) laser beam and the second (feedback) laser beam, so that in operation, the first beam hits the tissue first and the second beam hits it with a delay.

[0073] According to some embodiments, the optical fiber may be laterally separated by using two optical fibers configured to provide offset laser beams. According to some embodiments, the laser transmission element may include an isolation element, such as, but not limited to, a lens configured to widen the angular separation, for example, by 500-5000 microns, or 700-3000 microns, when the duodenal wall is reached (approximately 10-25 mm from the center of the catheter). As further described herein, it is understood that the distance between the ablation spot and the feedback spot may be determined by the focal length of the lens and the offset of the fiber. According to some embodiments, the lens may include several lenses, such as, but not limited to, a collimation lens and a focusing lens.

[0074] According to some embodiments, the optical fibers may be angularly separated. According to some embodiments, the first (ablation) and second (feedback) laser beams may be overlapping beams that are angularly separated using a separation element, such as, but not limited to, a dispersive element, a diffractive optical element, a prism, or other suitable element configured to selectively separate the first (ablation) laser beam and the second (feedback) laser beam. According to some embodiments, the distance between the ablation spot and the feedback spot may be determined by the type of separation element used. According to some embodiments, the overlapping beams may be transmitted by two separate optical fibers. According to some embodiments, the overlapping beams may be transmitted by a double clad fiber.

[0075] According to some embodiments, the spot size of the feedback beam is double-clad. The feedback beam can be determined / set by controlling the core diameter of the fiber and / or by controlling the divergence of the laser light emitted from the fiber. According to some embodiments, the apparatus can include a lens associated with the feedback beam.

[0076] According to some embodiments, the device may further include a rotating shaft configured to rotate the catheter and / or the laser transmission element or a portion thereof (e.g., the deflection element) during the ablation procedure. According to some embodiments, the rotating shaft may be made of at least two sections with different flexibilities. According to some embodiments, the rotating shaft may include a pivot point. This serves to ensure that the portion of the shaft including the laser transmission element is not moved by the forces applied to the shaft by the proximal segment when the distal portion of the duodenum is treated before the treatment of the more proximal portion, thus requiring a backward movement of the catheter, balloon and / or laser transmission element. That is, the shaft may be configured to withstand and / or remain stable despite forces perpendicular to the axis of the lumen / shaft caused by intestinal movements.

[0077] According to some embodiments, the device can include processing circuitry configured to assess the extent of the impact on a region of the duodenal wall based on the detected deformation of the region.

[0078] According to some embodiments, the processing circuitry may be configured to detect abnormalities and / or malfunctions in the ablation process, such as, but not limited to, improper expansion of the expandable member, improper termination of laser treatment, and / or faulty rotation of the beam. Each possibility is a separate embodiment.

[0079] Additionally or alternatively, the processing circuitry may be configured to determine and / or monitor a rotational velocity of the ablation beam and / or the feedback beam on the tissue.

[0080] Additionally or alternatively, the processing circuitry may be configured to determine a size, diameter, and / or shape of the expandable member based on a signal obtained from the feedback beam.

[0081] Additionally or alternatively, the processing circuitry can be configured to determine and / or monitor the diameter of the expanded portion, for example, by measuring the diameter of the expandable member once expanded.

[0082] Additionally or alternatively, the processing circuitry may be configured to detect previously treated portions, which may be of greatest importance when a portion of the duodenum requiring treatment extends the length of the expandable member and thus requires its repositioning.

[0083] Additionally or alternatively, the processing circuitry may be configured to enable identification of undesirable tissue, such as, but not limited to, the papilla of Vater or any other identifiable anatomical structure.

[0084] According to some embodiments, the processing circuitry may be configured to recommend ablation parameters (e.g., ablation power or pulse frequency) based on the degree of impact on the detected region of the duodenal wall. According to some embodiments, the processing circuitry may be configured to adjust the ablation parameters based on the degree of impact on the detected region of the duodenal wall.

[0085] According to some embodiments, the processing circuitry may be configured to correlate the extent of the detected effect with a histological observation.

[0086] According to some embodiments, the processing circuitry may be configured to identify non-target regions (e.g., bile ducts or pancreatic ducts) where ablation should be avoided based on signals obtained from the feedback beam. According to some embodiments, the processing circuitry may be configured to direct and / or position the catheter based on those identifications such that ablation of non-target regions is avoided. Additionally or alternatively, the positioning and / or orientation of the catheter and / or laser transmission element may be based on detection of non-target regions by endoscopy or by estimation of their location based, for example, on an anatomical map. According to some embodiments, the processing circuitry may be configured to stop and / or pause the beam when the laser beam reaches a non-target region and / or an already treated region.

[0087] According to some embodiments, the expandable member may be a balloon. According to some embodiments, the balloon may be semi-compliant or non-compliant. According to some embodiments, the balloon may expand the duodenum to a predetermined radius (using a non-compliant balloon) or a preset range of diameters (using a semi-compliant balloon) while conforming to the shape of the duodenal lumen along the longitudinal axis. The lack of compliance of the balloon may be critical to ensure that a predetermined dose of laser energy is used regardless of the angular orientation of the laser beam so that uniform ablation is obtained across the duodenal surface. This is because a semi / non-compliant balloon ensures that the rotating beam is derived from the center of the balloon and therefore the center of the duodenum. Ensuring uniform ablation is complicated by the fact that the inner shaft used to rotate the beam is subject to radial forces exerted by duodenal sections before and after the working area.

[0088] According to some embodiments, the ablation line is created when the duodenum is expanded / stretched to a diameter of 25-70 mm. According to some embodiments, the diameter is determined by a non-compliant balloon stretching the duodenum. According to some embodiments, a semi-compliant or compliant balloon may be used along with a means for determining the diameter to ensure that the desired dose can be determined and / or adjusted by modulation of the laser power and / or rotation speed.

[0089] According to some embodiments, the distance of the laser rotating element to the duodenal wall, i.e., the balloon radius, may be 12.5-25 mm, 15-30 mm, 18-25 mm, or any other suitable distance within the range of 12.5-35 mm. Each possibility is a separate embodiment. As a non-limiting example, the distance may be 18 mm.

[0090] According to some embodiments, the balloon, or other expandable member, can include multiple sections. According to some embodiments, the sections of the balloon can be interconnected by links that allow bending between the sections (e.g., 120 degree bends) to allow expansion of the duodenal lumen while maintaining its three-dimensional shape. According to some embodiments, the segments can be of the same or different lengths and / or diameters to fit the anatomy. According to some embodiments, the angle of the balloon wall between the segments can be minimized to 15 degrees (± 5 degrees) to reduce the "dead area" between the segments, as shown herein below. According to some embodiments, the connection points (also called bending sites) can serve as landing / support areas or axial sites for the rotating shaft.

[0091] According to some embodiments, the segments of the balloon can be inflated simultaneously or sequentially. According to some embodiments, the distal segment can be configured to inflate first to allow application of a pushing force and stretching of the catheter at the end of the catheter closest to the ablation target (e.g., the beginning of the duodenum after the pyloric junction). According to some embodiments, the force applied to stretch / stretch the catheter and duodenum can be from air pressure applied by the endoscope. According to some embodiments, the catheter can be stretched by applying a pushing force to or towards the distal portion of the catheter using the inner shaft.

[0092] According to some embodiments, the balloon distal facet is used as an anchor to stabilize the axis of the central shaft and is held in place using the pressure of the balloon.

[0093] According to some embodiments, the balloon (or optionally sections thereof) can be coated with parylene to increase thermal resistance to counter the heating effects on tissue exposed to the ablation laser beam, thus protecting the balloon from damage.

[0094] According to some embodiments, the balloon can include longitudinal lines configured to allow for determining the rotational speed of the first and / or second laser beams and / or the diameter of the balloon. According to some embodiments, the angular velocity of the ablation beam can be determined by measuring the modulation frequency of the feedback obtained from these lines as they rotate. According to some embodiments, the longitudinal lines can be located on the outer or inner surface of the balloon. According to some embodiments, the longitudinal lines can be made of metal, dye, heat-based marks or other materials that do not expand to ensure that the longitudinal lines maintain a constant width necessary to allow for the determination of the diameter of the balloon. This is by measuring the time it takes to cross the ablation line when the angular velocity is known, since the line velocity increases as the diameter increases, thus reducing the time required to scan the line.

[0095] According to some embodiments, a semi-compliant or compliant balloon may be used instead of a non-compliant or semi-compliant balloon to allow for greater flexibility in terms of the balloon diameter. This may allow for the use of a lower profile catheter since a balloon with less stretch can be accommodated in a smaller profile catheter than a larger PET balloon that can expand to 30-50 mm in diameter when compressed. Thus, a means is needed to determine the diameter of the expanded balloon at the target to ensure that the desired amount of ablation is applied.

[0096] According to some embodiments, the balloon can include a circumferential line (width band) configured to determine the linear velocity of the catheter and / or the laser transmission element.

[0097] According to some embodiments, interruptions and / or divergence of the signal obtained from back reflection of radiation from longitudinal and / or circumferential lines may be used to detect rotational disturbances, balloon malfunctions, malfunctioning optics, or any other suitable parameter or combination of parameters.

[0098] According to some embodiments, radiation reflected back from the longitudinal and / or circumferential lines can be used to calibrate the intensity of the laser beam used for ablation and / or feedback. According to some embodiments, free space or fiber beam splitters can be used. In such cases, radiation that does not reach the sample can be used. One of the channels can be used for calibration. According to some embodiments, the arm of the fiber splitter that projects the beam not directed at the tissue can be used to monitor the intensity of the laser beam directed at the tissue, normalize for fluctuations / changes in laser intensity, and / or control the laser power.

[0099] Additionally or alternatively, an imaging device such as a CMOS or CCD camera can be used to detect beam blockage and / or rotation cessation by detecting a frozen video signal.

[0100] According to some embodiments, the device may include a support member configured to stabilize the laser transmission element within the expandable member (e.g., within the balloon). According to some embodiments, the support member may be made from a shape memory material, such as, but not limited to, Nitinol.

[0101] In some embodiments, an inner wire is introduced into the balloon to: (i) pull the catheter to the distal end and tension it with a motor as it is pulled back. The motor pulls the shaft and maintains tension on the wire connected to the tip of the shaft to keep it centered; or (ii) have at least one, but preferably two or three wires maintained at minimal tension. The wires act as rails for the tip of the catheter sliding over / over them; or (iii) have a string that exerts a pulling force on the distal rotating tip, ensuring that it is centered on the balloon and oriented parallel to the lumen axis. The pulling force can be obtained, for example, from rubber or a suitable metal coil.

[0102] In some embodiments, means are included for detecting the macro 3D shape of the multi-balloon structure in the duodenum, making it possible to detect its position and orientation with respect to other geometric structures, such as to detect the angle / orientation of the main duodenal papilla (opening of the pancreatic duct into the duodenum) to disable laser firing in this area. This advantageously makes it possible to detect the position of the papilla and avoid ablation in this area, thus reducing the risk of blocking the passage of bile and pancreatic secretions into the duodenum. This can be based on one or more means, such as: (i) the use of optical means, such as a feedback signal, to detect the position; (ii) detection of the position of a pulling wire, which obtains its position according to the smaller curvature (and thereby the associated macroscopic orientation). Detecting the position of the papilla can be achieved by determining the inner curvature of the duodenum, due to the anatomical structure of the bile duct. Determining the inner curvature of the duodenum can be achieved by stretching a wire inside the balloon, which of course takes the inner curved side between the two bending points. Identifying this wire can be accomplished by using an endoscope or any other image of the balloon positioning, or by an encapsulated feedback mechanism that can identify the wire angle as described below.

[0103] Reference is now made to FIG. 1. FIG. 1 is an overview of an optical system 100 for ablating duodenal tissue (or other lumen in the GI or pulmonary tract) with real-time ablation feedback, according to some embodiments. The system 100 includes a first laser 110 configured to emit a first laser beam 112 configured to cause ablation of tissue it impinges upon. The first laser beam 112 may, for example, have a wavelength of about 1550 nm and a power of 10 W. The system 100 also includes a second laser 120 configured to emit a second laser beam 122, the backscattered light of which allows for evaluation of tissue deformation caused by the ablation. The second laser beam 122 may, for example, have a wavelength of about 980 nm and a fixed power density on the target. The first laser beam 112 The first and second laser beams 112 and 122 are directed to a first optical element, here a wavelength division multiplexing (WDM) system 130, which multiplexes multiple optical carrier signals into a single optical fiber and separates them at the exit. The WDM 130 allows for bidirectional communication and therefore allows for receiving a portion of the second laser beam 122 reflected back from the tissue and sending the reflected beam to a sensor 126 configured to detect its intensity, as indicated by arrow 124. Upon exiting the WDM system 130, the first and second laser beams 112 and 122 reach a second optical element, also referred to herein as a laser transmission element 140. The laser transmission element 140 is configured to generate a spatial separation between the first and second laser beams 112 and 122, as further described herein below in FIG. 2, thus allowing for a delay between the ablation first laser beam 112 and the feedback beam 122. The beams are then deflected using a third deflection optical element 150 (such as, but not limited to, a mirror or prism) configured to deflect the first laser beam 112 and the second laser beam 122 at an essentially 90 degree angle, which are then focused by a lens 152 onto a target area (indicated by box 190) within the duodenal wall. Importantly, to accommodate a maximum 1.8 mm diameter optical fiber and to maximize spatial separation between the beams, the laser transmission element 140 should preferably be located before the deflection element 150.

[0104] The deflection element 150 may be rotatable, such that the first laser beam 112 and the second laser beam 122 are deflected circumferentially around the duodenal wall, such that the first laser beam 112 generates an ablation line 154. The ablation line 154 causes a backscattering of the second laser beam 122 differently than untreated tissue. The power intensity of the back-reflected portion of the laser beam 122 detected by the sensor 126 may thus be used to assess the extent of the ablation damage / deformation caused.

[0105] Reference is now made to Figure 2, which illustrates two optional optical concepts (suitable for use as laser transmission element 140) for spatial separation of an ablation laser beam, such as first laser beam 112, and a feedback beam, such as second laser beam 122.

[0106] According to the first concept, the spatial separation of the beams can be achieved by lateral separation of the laser beams. That is, at the beginning, the laser beams can be offset, for example, by using two separate optical fibers. Due to their initial offset, the beams impinge on a separation element, such as, but not limited to, a collimating lens, at different positions, thereby displacing and / or diverging, for example, the ablation beam relative to the feedback beam. It is understood that according to this embodiment, the degree of separation can be determined by the initial offset of the laser beams and / or the focal length (divergence) of the beams. Furthermore, it is understood that in order to maximize the return acceptance angle, the feedback beam should preferably be placed in the center of the beam.

[0107] According to the second concept, the spatial separation of the beams can be achieved by angular separation of the laser beams. That is, at the start, the laser beams can be overlapped, for example by using a double-clad optical fiber, and pass through a lens together. In this case, a separation element in the form of a dispersive element, a DOE, a prism, or other optical element allowing wavelength-discriminating refraction of the beams can be included. This element can differentially refract and / or displace, for example, the ablation beam, while allowing the feedback beam to pass undiverged. It is understood that according to this embodiment, the degree of separation can be determined by the type of dispersive element utilized.

[0108] According to some embodiments, the separation of the impingement points of the ablation beam and the feedback beam is , is further determined by the distance between the center of the catheter through which the laser radiation is transmitted and the target area within the duodenal wall, which in turn depends on the diameter / radius of the expandable member (e.g., 16-23 mm), as exemplarily shown in Figure 3. In addition, it will be appreciated that the magnitude of delay between the ablation beam and the feedback beam at a particular point on the duodenal wall may be determined by the degree of separation and rotation speed of the beams.

[0109] According to some embodiments, in order to evaluate photothermal and / or photochemical processes occurring in tissue adjacent to the impingement point of the ablation beam, the feedback beam can have a spot diameter larger than that of the ablation beam as shown in FIG. 4. FIG. 4 shows a schematic of the difference in spot diameters, here a feedback (probe) spot diameter 420 of 400-2000 microns and an ablation spot diameter 410 of 50-200 microns. The difference in spot diameters can be achieved, for example, by using an optical fiber with a larger core diameter for the feedback beam compared to the ablation beam. Alternatively, when using a double clad fiber, the ablation beam can be transmitted through the core of the double clad fiber while the feedback beam is transmitted (and collected) through the cladding. In yet another alternative, both laser beams are transmitted through the core fiber and the cladding is used to collect scattered light from the ablation spot. According to some embodiments, a delay of x0.1-0.5 seconds, obtained for example by a spot separation of 700-3000 microns and a scan speed of 1.5 mm / s, allows the feedback beam to reach the impact area long enough for photothermal and / or photochemical processes to occur. Additionally, due to the larger spot diameter of the feedback beam, nearly the entire impact area, such as impact area 430 caused by previous impacts of the laser beam, can be evaluated.

[0110] 5A and 5B, which respectively show a configuration 500a suitable for using two separate optical fibers to deliver the ablation beam and the feedback beam, and a configuration 500b suitable for using a combiner (e.g., a double-clad optical fiber). According to some embodiments, a significant difference in spot diameter between the ablation beam and the feedback beam is more easily achieved by using separate optical fibers, as shown in configuration 500a compared to configuration 500b.

[0111] Reference is now made to FIG. 6. FIG. 6 illustrates, in schematic form, an expandable member, here a balloon 600, configured to stretch and / or expand the duodenum to a predetermined diameter or range of diameters, according to some embodiments. According to some embodiments, the balloon 600 can include longitudinal marks 610. The longitudinal marks 610 can be configured to allow for determining the rotational speed of the first and / or second laser beams and / or the diameter of the balloon. According to some embodiments, the angular velocity of the ablation beam can be determined by measuring the modulation frequency of the feedback obtained from the lines 610 upon rotation. According to some embodiments, the longitudinal lines 610 can be located on the outer or inner surface of the balloon. According to some embodiments, the longitudinal lines can be made of metal, dye, heat-based marks or other materials that do not expand, to ensure that the longitudinal lines maintain a constant width necessary to allow for the determination of the diameter of the balloon. According to some embodiments, the balloon 600 can further include a circumferential line (width band) 620 configured to determine the linear velocity of the catheter and / or the laser transmission element. According to some embodiments, the balloon 600 may be coated with parylene to increase thermal resistance, to counter the heating effects on tissue exposed to the ablation laser beam, and / or to direct the laser beam.

[0112] Reference is now made to Figure 7, which illustrates a schematic of a balloon 700 having multiple balloon segments 710, three of which are shown here. In one embodiment, the balloon segments 710 can be interconnected by connection points 720 that allow bending (e.g., 120 degree bending) between segments to allow expansion of the duodenal lumen while maintaining its 3D shape in both its folded configuration and its inflated form, as shown in FIG. 8A and FIG. 8B, respectively. According to some embodiments, the balloon segments 710 can have essentially the same length and / or diameter as shown herein, and / or can have different lengths and / or diameters to follow the anatomical structure. Options not shown. According to some embodiments, the balloon segments 710 can be inflated simultaneously or sequentially. According to some embodiments, the distal of the balloon segments 710 can be configured to inflate first to allow application of catheter push force and catheter stretching at the end of the catheter closest to the ablation target (e.g., the beginning of the duodenum after the pyloric junction). According to some embodiments, each balloon segment, or several balloon segments (e.g., the most distal balloon segment), can include longitudinal and / or circumferential markings, as described in FIG. 6. According to some embodiments, the balloon segment 710 may be coated with parylene to increase thermal resistance, to counter the heating effects on tissue exposed to the ablation laser beam, and / or to direct the laser beam.

[0113] Reference is made to Figure 9. Figure 9 illustrates a schematic of an expandable member, here a balloon 900, configured to stretch and / or expand the duodenum to a predetermined diameter or range of diameters, according to some embodiments. The balloon 900 includes a support member 910 configured to stabilize a laser transmission element within the balloon 900. According to some embodiments, the support member may be made from a shape memory material, such as, but not limited to, Nitinol.

[0114] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural unless the context clearly indicates otherwise. It will be further understood that as used herein, the term "comprises" or "comprising" specifies the presence of a stated feature, integer, step, operation, element, or component, but does not exclude or preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. According to some embodiments, the term "comprises" may be replaced with the term "consisting essentially of" or "consisting of".

[0115] While several exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, additions, and subcombinations thereof. It is therefore intended that the appended claims and those introduced below be construed to include all such modifications, additions, and subcombinations as are within their true spirit and scope.

[0116] Working Example EXAMPLES

[0117] Correlation between ablation power and detected feedback signal power

[0118] The ability of the system disclosed herein to assess ablation impact is illustrated in Figure 10, which shows an essentially linear correlation between ablation power and the strength of the signal detected by the feedback sensor using the setup shown in Figure 5A. This demonstrates that the ablation / feedback system disclosed herein is able to assess the impact of ablation on duodenal tissue. It is clearly shown that it can be used to evaluate the extent of the impact of the ablation beam. EXAMPLES

[0119] Ex vivo offline analysis of duodenal ablation

[0120] Ex vivo analysis was performed on duodenal tissue segments ablated using a single mode laser beam essentially as described herein. Following ablation, a second feedback beam was used to scan the ablation line vertically at a constant speed, as essentially described herein. As can be seen in FIG. 11A and FIG. 11B, different feedback intensities were readily detectable for non-ablated versus ablated tissue. Furthermore, comparison of the figures demonstrated that an ablation line visually observed as a thin ablation line, such as ablation line A, provided a narrow feedback curve, such as feedback curve 1. Similarly, an ablation line observed as a wider ablation line, such as ablation line B, when scanned by the laser, appeared as a wider ablation curve 2. This clearly demonstrates that the ablation / feedback system disclosed herein provides a reliable quantitative assessment of the impact of ablation on tissue. EXAMPLES

[0121] In vivo real-time analysis of duodenal ablation

[0122] In this example, a standard catheter was used to collect backscattered / backreflected beams during in vivo tissue ablation of porcine duodenum using a 1550 nm, 10 W laser. Concurrently with ablation (at a predefined delay), the effect of ablation on the duodenal tissue was assessed by laterally separating the beams using a second laser with a wavelength of 980 nm essentially as illustrated in Figure 5A.

[0123] As can be seen from FIG. 12, the evaluation of the power intensity of the feedback beam clearly indicated a globally homogenous ablation of the duodenal tissue. Moreover, at one point where the ablation laser beam was directed at the same target area over an extended period of time, ablation exceeding the upper ablation threshold level (indicated by horizontal line T2) was readily identified. This result clearly demonstrates that the systems and methods for ablation feedback evaluation disclosed herein enable immediate identification of excessive ablation events, thus allowing the ablation procedure to be paused and / or terminated before damage (such as, but not limited to, perforation) is caused to the tissue.

[0124] The above described examples are non-limiting examples and are not intended to limit the scope of the present disclosure. The described examples may include different features, not all of which are required in all embodiments of the present disclosure.

Claims

1. An ablation device comprising a catheter, The catheter comprises: an expandable member configured to radially stretch a wall of the GI tract to create a fixed radial distance between a center of the catheter and the wall, wherein expansion of a balloon creates a fixed distance between the center of the catheter and the wall; and a laser transmission element coupled to the catheter and configured to transmit a first laser beam and a second laser beam, the first laser beam has a first wavelength and a first spot diameter and is configured to cause an ablation lesion in a region of the GI tract as a result of impingement against the region; the second laser beam having a second wavelength and a second spot diameter and configured to enable detection of an ablation lesion within the region of the GI tract resulting from impingement of the first laser beam on the region; a laser transmission element, the second spot diameter being greater than the first spot diameter; and a rotatable deflection optical element operatively coupled to a laser emitter and configured to direct the first laser beam and / or the second laser beam at a wall of the gastrointestinal tract.

2. The apparatus of claim 1, wherein when the deflecting optical element is rotated, the second laser beam impinges on the region of the wall later than the impingement of the first laser beam.

3. The apparatus of claim 1 , wherein the laser transmission element further comprises a lens configured to deflect the first laser beam.

4. The laser light emitting element comprises a double clad fiber, The apparatus of claim 1 , wherein the first laser beam is transmitted through a core of the double-clad fiber and the second laser beam is transmitted through a cladding of the double-clad fiber.

5. 10. The apparatus of claim 1, wherein the laser transmission element further comprises a dispersive element configured to selectively refract the first laser beam and / or the second laser beam.

6. 2. The apparatus of claim 1, wherein the first wavelength is 1550 nm, 1567 nm or 980 nm.

7. The apparatus of claim 1 , wherein the second wavelength is 532 nm.

8. The apparatus of claim 1, wherein the second laser beam is transmitted through a multimode fiber.

9. The device of claim 1 , wherein the expandable member is a non-compliant balloon or a semi-compliant balloon.

10. The device of claim 1, wherein the balloon comprises a plurality of balloon segments.

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