Coherence tomography-based laser fiber distance measurement

Abstract

Systems, devices, and methods for providing adjustable laser treatment of a target using fiber-target distance measurements are disclosed. An exemplary surgical laser system comprises a laser system for generating and delivering laser pulses to an anatomical target via an optical fiber, a feedback analyzer circuit for receiving a returning laser signal in response to a chirped laser beam directed at the target, and a control unit. Using the chirped laser and the returning laser signal, the feedback analyzer circuit can generate an optical coherence metric and determine the fiber-target distance between a distal end of the optical fiber and the target.Based at least on the distance between the fiber and the target, the control unit can adjust the position or orientation of the distal end of the optical fiber or adjust a surgical laser delivery setting to generate and deliver laser pulses to the target.

Description

PRIORITY CLAIM

[0001] This application claims priority over the preliminary US patent application with serial number 63 / 580,161, which was filed on September 1, 2024, and the contents of which are hereby incorporated by reference. AREA OF REVELATION

[0002] This document refers generally to endoscopic laser surgery systems and in particular to systems and methods for measuring the distance between a laser fiber and a treatment target, and for optimizing laser treatment based on the measured distance. BACKGROUND

[0003] Endoscopes are used in a variety of clinical procedures, including illumination, imaging, detection and diagnosis of one or more disease conditions, delivery of fluids (e.g., saline or other preparations via a fluid channel) to an anatomical region, provision of a passage (e.g., via a working channel) for one or more therapeutic devices or devices for the collection of biological substances for sampling or treatment of an anatomical region, and provision of suction passages for the collection of fluids (e.g., saline or other preparations), as well as for other procedures. Examples of such anatomical regions include the gastrointestinal tract (e.g., esophagus, stomach, duodenum, pancreatic and biliary tracts, intestines, colon, and the like), the renal region (e.g., kidney(s), ureter(s), bladder, urethra), and other internal organs (e.g.,Reproductive systems, sinuses, submucosal regions, respiratory tract) and the like.

[0004] Some endoscopes have a working channel through which the operator can perform suctioning, place diagnostic or therapeutic instruments (e.g., a brush, biopsy needle or forceps, stent, basket, or balloon), or perform minimally invasive procedures such as tissue sampling or the removal of unwanted tissue (e.g., benign or malignant strictures) or foreign bodies (e.g., stones). Some endoscopes can be used with a laser or plasma system to deliver energy to an anatomical target (e.g., soft or hard tissue or a stone) to achieve the desired treatment. Lasers are used, for example, for tissue ablation, coagulation, vaporization, fragmentation, and lithotripsy to break up stones in the kidney, gallbladder, ureter, and other stone-forming regions, or to fragment large stones into smaller pieces. SUMMARY

[0005] When treating various diseases and conditions with a laser surgery system, the distance between the distal end of a laser fiber (or the distal tip of a device such as an endoscope into which the laser fiber is integrated) and the anatomical target being treated (hereinafter referred to as the "fiber-target distance") is a crucial factor that can determine the success of the procedure. For example, when ablating tissue, if the laser fiber is too close to the target, flashes of light, fiber damage, and tissue adhesion can occur. If the fiber is too far from the target, more energy is required to achieve the desired therapeutic effect on the tissue.

[0006] Traditionally, the ideal or optimal distance between the fiber and the target depends heavily on the operator's (e.g., an endoscopist's) experience. Based on this "best possible estimate" of the ideal fiber-target distance, the operator manually positions the laser fiber relative to the treatment target to achieve the desired distance. This approach places high demands on operator experience and can therefore lead to variations between different operators or facilities, particularly in challenging cases where the treatment target has complex structures, compositions, or shapes, or is located in difficult-to-access areas.Manually positioning the laser fiber according to the desired distance between the fiber and the target typically requires considerable time and effort and can lead to operator fatigue, especially when constant repositioning of the fiber is necessary throughout the procedure to treat complex targets. For these reasons, at least, the inventor recognized an unmet need for devices and methods to automate the process of measuring the distance between the fiber and the target and adjusting the laser fiber positions during a laser procedure.

[0007] This document describes systems, devices, and methods for measuring the distance between a laser fiber and a treatment target during a laser treatment procedure and for optimizing the laser treatment of the target using the measured distance. An exemplary surgical laser system comprises a laser system for generating and delivering laser pulses to a target in a patient's anatomical environment via an optical fiber, a feedback analyzer circuit for receiving a returning laser signal from the target in response to a chirped laser emitted by the laser system and directed at the target, and a control unit.The feedback analyzer circuit can use at least a portion of the chirped laser and the returning laser signal to generate an optical coherence metric correlated with the laser orbital period between a distal end of the optical fiber and the target, and to determine a fiber-to-target distance based on this optical coherence metric. Based at least on this fiber-to-target distance, the control unit can adjust the position or orientation of the distal end of the optical fiber and adapt a surgical laser power setting to generate and deliver laser pulses to the target.

[0008] Example 1 is a surgical laser system comprising: a laser system configured to generate laser pulses and deliver them via an optical fiber to a target in a patient's anatomical environment; and a control unit comprising a feedback analyzer circuit configured to: receive a returning laser signal from the target in response to a chirped laser emitted by the surgical laser system and directed at the target; generate an optical coherence metric using at least a portion of the chirped laser and the returning laser signal, the optical coherence metric being correlated with the laser orbital period between a distal end of the optical fiber and the target;and determining a fiber-to-target distance between the distal end of the optical fiber and the target using the optical coherence metric, wherein the control unit is configured to generate a control signal to adjust a position or orientation of the distal end of the optical fiber relative to the target at least partially based on the determined fiber-to-target distance.

[0009] In Example 2, the subject of Example 1 optionally includes the feedback analyzer circuit, which can be configured to further determine the distance between the fiber and the target object based on a chirp rate of the chirped laser.

[0010] In Example 3, the subject of one or more of Examples 1-2 optionally includes the control unit that can be configured to adjust a surgical laser power setting of the surgical laser system at least partially on the basis of the determined distance between the fiber and the target object.

[0011] In Example 4, the subject of one or more of Examples 1 to 3 optionally comprises a light source configured to direct electromagnetic radiation onto the target, wherein the feedback analyzer circuit is configured to detect a reflected image signal from the target in response to the electromagnetic radiation directed at the target; to determine a spectroscopic property of the target from the reflected imaging signal; and to identify a target type or composition at least partially based on the determined spectroscopic property of the target.

[0012] In Example 5, the subject of Example 4 optionally includes the control unit, which may be configured to further generate the control signal for adjusting the position or orientation of the distal end of the optical fiber relative to the target, based on the identified target type or composition.

[0013] In Example 6, the subject of one or more of Examples 4-5 optionally includes the control unit, which may be configured to adjust a surgical laser power setting of the surgical laser system at least partially on the basis of the identified target type or target composition.

[0014] In Example 7, the subject of one or more of Examples 4 to 6 optionally includes the optical fiber, which may be configured to simultaneously direct the laser pulses and the reflected image signal.

[0015] In Example 8, the subject of one or more of Examples 1 to 7 optionally includes the control unit, which may be configured to supply the control signal to a robotic arrangement coupled to the optical fiber in order to robotically adjust the position or orientation of the distal end of the optical fiber relative to the target.

[0016] In Example 9, the subject of one or more of Examples 1 to 8 optionally includes a user interface configured to display to a user the determined distance between the fiber and the target, as well as a recommendation to adjust the position or orientation of the distal end of the optical fiber relative to the target.

[0017] In Example 10, the subject of one or more of Examples 1 to 9 optionally includes the target, which may be a tissue target, wherein the surgical laser system is configured to generate and deliver the laser pulses to treat the tissue target.

[0018] In Example 11, the subject of one or more of Examples 1 to 10 optionally includes the target, which may be a stone target, wherein the surgical laser system is configured to generate and deliver the laser pulses to ablate or fragment the stone.

[0019] In Example 12, the subject matter of one or more of Examples 1 to 11 optionally includes an endoscope containing or coupled to the surgical laser system, the endoscope comprising a longitudinal channel for passing the optical fiber.

[0020] In Example 13, the subject of one or more of Examples 1 to 12 optionally includes the feedback analyzer circuit, which can be configured to: identify one or more outlier measurements from a plurality of fiber-to-target distance measurements generated over time; filter the plurality of fiber-to-target distance measurements to exclude the identified one or more outlier measurements; and determine the fiber-to-target distance using the filtered plurality of fiber-to-target distance measurements.

[0021] In Example 14, the subject of Example 13 optionally includes the feedback analyzer circuit, which can be set up to identify one or more outlier measurements based on an average and variance of the majority of fiber-to-target distance measurements.

[0022] Example 15 is a method for feedback control of a surgical laser system during laser surgery on a patient, the method comprising the following steps: directing a chirped laser through an optical fiber of the surgical laser system toward a target in an anatomical environment of the patient and receiving a returning laser signal from the target in response to the irradiation of the target with the chirped laser; generating an optical coherence metric using at least a portion of the chirped laser and the reflected laser signal, wherein the optical coherence metric is correlated with the laser orbital period between a distal end of the optical fiber and the target; determining a fiber-to-target distance between the distal end of the optical fiber and the target using the optical coherence metric;and adjusting the position or orientation of the distal end of the optical fiber relative to the target, at least partially based on the determined fiber-to-target distance.

[0023] In Example 16, the subject of Example 15 optionally includes the determination of the distance between the fiber and the target, which is additionally based on a chirp rate of the chirped laser.

[0024] In Example 17, the subject of one or more of Examples 15-16 optionally includes adjusting a surgical laser power setting of the surgical laser system, at least partially based on the determined distance between fiber and target.

[0025] In Example 18, the subject of one or more of Examples 15 to 17 optionally includes directing electromagnetic radiation toward the target; receiving a reflected image signal from the target in response to the electromagnetic radiation; determining a spectroscopic property of the target from the reflected image signal; and identifying a target type or composition, at least partially based on the determined spectroscopic property of the target.

[0026] In Example 19, the subject of Example 18 optionally includes adjusting the position or orientation of the distal end of the optical fiber relative to the target, which may further be based on the identified target type or composition.

[0027] In Example 20, the subject of one or more of Examples 18-19 optionally includes adjusting a surgical laser output setting of the surgical laser system, at least partially based on the identified target type or target composition.

[0028] In Example 21, the subject of one or more of Examples 15 to 20 optionally includes the target, which may be a tissue target or a stone target.

[0029] In Example 22, the subject of one or more of Examples 15 to 21 optionally includes providing a control signal to a robotic arrangement coupled to the optical fiber in order to robotically adjust the position or orientation of the distal end of the optical fiber relative to the target.

[0030] In Example 23, the subject of one or more of Examples 15 to 22 optionally includes the display of the determined distance between fiber and target, as well as a recommendation for adjusting the position or orientation of the distal end of the optical fiber relative to the target on a user interface.

[0031] In Example 24, the subject of one or more of Examples 15 to 23 optionally includes identifying one or more outlier measurements from a plurality of fiber-to-target distance measurements, each generated over time based on appropriate optical coherence metrics; filtering the plurality of fiber-to-target distance measurements to exclude the identified one or more outlier measurements; and determining the fiber-to-target distance using the filtered plurality of fiber-to-target distance measurements.

[0032] In Example 25, the subject of Example 24 optionally includes identifying the one or more outlier measurements based on an average and variance of the majority of fiber distance measurements to the target.

[0033] The systems, devices, and procedures described here can be used in various endoscopic laser surgery procedures to improve the success rate of the operations. The fiber-to-target distance measurement and automatic fiber positioning described here can help reduce operator-to-operator variance associated with the subjective "best possible estimate" of the fiber-to-target distance, leading to more consistent and predictable surgical outcomes. The optical time-of-flight (ToF) method, as used in the automated fiber-to-target distance measurement, can provide more accurate and precise distance measurements.Compared to conventional methods, which are limited by inaccuracies at close range due to the short flight time of the pulses, time-of-flight (ToF) methods, such as optical coherence tomography (OCT) or frequency-modulated continuous wave (FMCW), can eliminate or reduce time jitter and offer higher accuracy, particularly for distance measurements at close range. According to some embodiments described here, fiber-to-target distance measurements can be filtered by automatically excluding outlier measurements identified using a statistical outlier detector, resulting in a more refined fiber-to-target distance. Automatic fiber-to-target distance measurement and fiber position control can lead to reduced user fatigue and faster procedures.Autonomous control of the laser fiber's retraction and extension enables more effective use of the laser system. Precise measurement of the distance between the fiber and the target, along with automatic control of the laser fiber's position, can also help prevent laser flashes, reduce the heating effect on fluids and tissues around the target, and achieve more efficient use of laser energy, as well as overall cost savings.

[0034] The systems, devices, and techniques described in this document according to various embodiments can be used in various endoscopic procedures involving laser treatment of tissue or other targets, including, for example, colonoscopy, anoscopy, arthroscopy, bronchoscopy, colposcopy, cystoscopy, esophagoscopy, gastroscopy, laparoscopy, laryngoscopy, neuroendoscopy, proctoscopy, sigmoidoscopy, thoracoscopy, etc.

[0035] This summary provides an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the subject matter. Further details of the subject matter can be found in the detailed description and the attached claims. Other aspects of the disclosure will be apparent to a person skilled in the art after reading and understanding the following detailed description and considering the drawings, which form part thereof; these are not to be understood in a limiting sense. The scope of the present disclosure is defined by the attached claims and their legal equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various embodiments are illustrated by way of example in the figures of the accompanying drawings. These embodiments serve for illustrative purposes and are not to be understood as exhaustive or exclusive embodiments of the present subject matter. Fig. Figure 1 is a block diagram showing an example of a laser energy system set up to perform laser treatment on an anatomical target. Fig. Figure 2 is a block diagram depicting a laser surgery system for providing adjustable laser treatment of a target using feedback information including fiber-to-target distance measurements. Fig. Figure 3 shows an example of a feedback-controlled endoscopic laser surgery system with automatic measurement of the fiber-to-target distance and optical fiber position control. Fig. 4A and Fig.Figure 4B shows diagrams illustrating the operating principle of using a frequency-modulated continuous wave (FMCW) method to estimate the distance between fiber and target. Fig. 5A-5B are diagrams that illustrate an example of how air bubbles affect the measurement of the fiber-to-target distance. Fig. Figure 6 shows an example of an overestimation of the fiber-to-target distance due to air bubbles present in the light path of the laser pulses. Fig. Figure 7 is a flowchart illustrating an example procedure for providing feedback control of a surgical laser system to provide adjustable laser treatment of a target using feedback incorporating measurements of the distance between the fiber and the target. Fig.Figure 8 is a block diagram showing an example of a machine on which one or more of the techniques (e.g., methodologies) described herein can be performed. DETAILED DESCRIPTION

[0037] This document describes systems, devices, and methods for providing adjustable laser treatment of a target using feedback, including fiber-to-target distance measurements. An exemplary surgical laser system comprises a laser system for generating and delivering laser pulses to a target in a patient's anatomical environment via an optical fiber, a feedback analyzer circuit for receiving a returning laser signal from the target in response to a chirped laser emitted by the laser system and directed at the target, and a control unit.The feedback analyzer circuit can use at least a portion of the chirped laser and the returning laser signal to generate an optical coherence metric correlated with the laser orbital period between a distal end of the optical fiber and the target, and to determine a fiber-to-target distance based on this optical coherence metric. The control unit can programmably adjust the position or orientation of the distal end of the optical fiber and set a surgical laser power level for generating and delivering laser pulses to the target, based at least on the fiber-to-target distance.

[0038] Fig.Figure 1 is a block diagram showing an example of a laser energy system 100 configured to perform laser treatment on a target structure 122 in an anatomical environment of a subject, such as an anatomical structure (e.g., soft tissue, hard tissue, or abnormal tissue such as cancerous tissue) or a stone structure (e.g., kidney, pancreatic, or gallstone). In some examples, the laser energy delivery system 100 can perform a precisely controlled therapeutic treatment of tissue or other anatomical structures (e.g., tissue ablation, coagulation, vaporization, or the like) or a treatment of non-anatomical structures (e.g., ablation or atomization of calculus structures).

[0039] The laser energy supply system 100 can comprise a feedback control system 101 and at least one laser system that is operationally connected to the feedback control system 101. By way of example and without limitation, the following shows Fig.1 The laser feedback system, which is connected to a first laser system 102 and optionally (represented by dotted lines) to a second laser system 104. Further laser systems are provided within the scope of this disclosure. The first laser system 102 can comprise a first laser source 106 and associated components such as power supply, display, cooling systems, and the like. The first laser system 102 can also comprise a first optical path 108, which is functionally coupled to the first laser source 106. In one example, the first optical path 108 comprises an optical fiber. The first optical path 108 can be configured to transmit laser beams from the first laser source 106 to the target structure 122.

[0040] The feedback control system 101 can receive feedback signals 130 from the target. In one example, the feedback signals 130 can include signals indicating properties of the target or conditions of the surgical site. In another example, the feedback signals 130 can include an acoustic signal generated by a laser pulse propagating through the medium (e.g., liquid and vapor), projected onto the target, and causing the target to vibrate. In yet another example, the feedback signals 130 can include reflected electromagnetic signals (e.g., reflected illumination emitted by a light source). In yet another example, the feedback signals 130 can include images or video images of at least part of the surgical site, such as those generated by an imaging sensor during a procedure.In another example, the feedback signals 130 can include a returning laser signal in response to laser pulses directed at the target. The laser pulses can be generated by the first system 102 or the second system 104 according to a specific output setting, such as a chirped laser. The returning laser signal can be used to determine whether the target is within the laser firing range, as described below in relation to the... Fig. 2-3 is described.

[0041] The feedback signals 130 can be used to control the laser output, laser energy output, and / or other system parameters to improve the effectiveness of the therapy and to achieve or maintain a desired condition in the target area. For example, the feedback control system 101 can analyze the feedback signals 130 to determine one or more target properties. Based on the determined target properties, the feedback control system 101 can identify the target type or composition, adjust a laser power setting (e.g., one or more laser irradiation parameters such as power, duration, frequency, pulse shape, exposure time, or beam angle) or other system parameters, and generate and deliver laser pulses to the target according to the laser power setting to achieve a desired therapeutic effect or maintain a desired condition.For example, the feedback control system 101 can monitor properties of the target structure during a therapeutic procedure (e.g., ablating stones such as kidney stones into smaller fragments) to determine whether the tissue has been adequately ablated prior to another therapeutic procedure (e.g., coagulation of blood vessels). In another example, the feedback control system 101 can analyze the feedback signals 130 to automatically determine a distance between a distal end of the laser fiber and the target tissue to be treated, also referred to in this document as the "fiber-to-target" distance. The fiber-to-target distance can be used to guide the manual or autonomous positioning of the laser fiber (e.g., retracting or moving the distal end of the laser fiber forward or backward, or changing its orientation) to achieve more efficient laser treatment of the target.

[0042] In one example, the first laser source 106 can be configured to provide a first output 110. The first output 110 can extend over a first wavelength range, for example, one corresponding to a portion of the absorption spectrum of the target structure. The first output 110 can effect effective ablation and / or carbonization of the target structure because the first output 110 extends over a wavelength range corresponding to the absorption spectrum of the tissue.

[0043] In one example, the first laser source 106 can be configured such that the first output 110, emitted in the first wavelength range, corresponds to a high absorption (e.g., over approximately 250 cm⁻¹) of the incident first output 110 by the tissue. In other examples, the first laser source 106 can emit a first output 110 between approximately 1900 nanometers (nm) and approximately 3000 nm (e.g., corresponding to high absorption by water) and / or between approximately 400 nm and approximately 520 nm (e.g., corresponding to high absorption by oxyhemoglobin and / or deoxyhemoglobin). There are essentially two main mechanisms of light interaction with tissue: absorption and scattering.If the absorption of a tissue is high (absorption coefficient above 250 cm-1), the first absorption mechanism dominates, and if the absorption is low (absorption coefficient below 250 cm-1), for example with lasers in the wavelength range of 800 to 1100 nm, the scattering mechanism dominates.

[0044] Several commercially available, medical-grade laser systems can be suitable for the first laser source 106. Examples of laser source 106 include UV-VIS emitting InXGa1-XN semiconductor lasers, such as GaN lasers with emission at 515–520 nm, InXGa1-XN lasers with emission at 370–493 nm, GaXAll-XAs lasers with emission at 750–850 nm, or InXGa1-XAs lasers with emission at 904–1065 nm. Alternatively, infrared lasers (IR lasers) can be used, as summarized in Table 1 below. Table 1: Exemplary list of suitable IR lasers Laser Wavelengthλ (nm) Absorption coefficient µ a (cm -1 ) Optical penetration depthδ (µm) Thulium fiber laser: 1908 88 / 150 114 / 67 Thulium fiber laser: 1940 120 / 135 83 / 75 Thulium YAG: 2010 62 / 60 161 / 167 Holmium: YAG: 2120 24 / 24 417 / 417 Erbium:YAG: 2940 12.000 / 1.000 1 / 10

[0045] The optional second laser system 104 may include a second laser source 116 for providing a second output 120 and associated components such as power supply, display, cooling systems, and the like. The second laser system 104 may be either functionally separate from the first laser source 106 or, alternatively, functionally coupled to it. In some embodiments, the second laser system 104 may include a second optical path 118 (separate from the first optical path 108) that is functionally coupled to the second laser source 116 to transmit the second output 120. Alternatively, the first optical path 108 may be configured to transmit both the first output 110 and the second output 120.

[0046] In certain aspects, the second edition 120 may extend over a second wavelength range that differs from the first wavelength range. Accordingly, there need not be any overlap between the first and second wavelength ranges. Alternatively, the first and second wavelength ranges may overlap, at least partially. In advantageous aspects of the present disclosure, the second wavelength range may not correspond to portions of the absorption spectrum of the target structure where incident radiation is strongly absorbed by tissue that has not been previously ablated or carbonized. In some such aspects, the second edition 120 may advantageously not ablate non-carbonized tissue. In another embodiment, the second edition 120 may ablate carbonized tissue that has been previously ablated.In further embodiments, the second outlet 120 can achieve additional therapeutic effects. For example, the second outlet 120 may be better suited for the coagulation of tissue or blood vessels.

[0047] Fig. Figure 2 is a block diagram illustrating a laser surgery system 200 for performing feedback-controlled laser treatment of a target using feedback information, including fiber-to-target distance measurements. The system 200 can be an embodiment of the laser energy delivery system 100 for treating various types of anatomical targets or a lithotripsy system for breaking up hardened masses such as kidney stones, bezoars, gallstones, and other stones.

[0048] The laser surgery system 200 can include a feedback control system 210, one or more sensors 220, a laser system 230, a light source 240, a user interface 250, and an actuator 260. The laser system 230, which is an example of the one in Fig.The laser system 102 or laser system 104 shown in Figure 1 can include a laser source 232 (which can be, for example, the first laser source 106 or the second laser source 116) and an optical fiber 234 (which can be the first optical path 108 or the second optical path 118) for directing the laser energy to the target structure 122. The laser source 232 can generate laser pulses according to an output setting, which can include one or more laser irradiation parameters (e.g., intensity, power, duration, frequency or pulse shape, exposure time, or beam angle). At least some of the laser irradiation parameters are either automatically programmable or adjustable, for example, by the control unit 218, or manually by a user via the user interface 250. The laser pulses can be used for therapeutic purposes, for example, for the surgical removal or extraction of tissue or for ablating a stone.In some examples, the laser source can generate 232 laser pulses for non-therapeutic purposes, such as estimating a fiber-to-target distance, as described in this document according to various embodiments. In some examples, the laser source can comprise 232 different laser sources, including a first laser source (such as the one in ). Fig. 1 first laser source 106) shown for generating the therapeutic laser pulses and a second laser source (such as the one in Fig. 1 second laser source 116) shown for generating non-therapeutic laser pulses which can be used to estimate a fiber-to-target distance.

[0049]

[0001] The feedback control system 210, which is an embodiment of the in Fig.The feedback control system 101 shown in Figure 1 can comprise a feedback analyzer 212 and a control unit 218. According to exemplary embodiments, the feedback control system 210 or a part thereof (such as the feedback analyzer 212 and / or the control unit 218) can include processors, such as microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits, as well as any combination of such components, to perform one or more of the functions assigned to the control system 210.

[0050] The feedback analyzer 212 can be communicatively coupled with one or more sensors 220, receive feedback information from them, determine a target property based on this feedback information, and control the laser system 230 to provide a suitable laser treatment, at least partially based on the target property. This is an example without limitation, as shown in Fig. As shown in Figure 2, the one or more sensors 220 can comprise an imaging sensor 222 and a back laser detector 224. The imaging sensor 222 can be included in an imaging system, which further comprises a lens system. Examples of the imaging sensor 222 include a CCD or CMOS camera sensitive to ultraviolet (UV), visible (VIS), or infrared (IR) wavelengths. The imaging sensor 222 can be located on a distal section of an endoscope used during the procedure, as shown in Figure 2. Fig.Figure 3 illustrates this. The imaging sensor 222 can acquire an image signal of at least a portion of the target structure 122 during the procedure. In one example, the light source 240 can generate electromagnetic radiation and direct it toward the target structure 122, and the imaging sensor 222 can acquire the image signal in response to the electromagnetic radiation incident on the target structure 122. Table 2 below shows examples of the light source 240 suitable for the examples discussed herein. Table 2: Light sources for spectroscopic systems Application Wavelength range type Color / VIS / NIR 360-2500 nm Tungsten Halogen DUV 190-400 nm deuterium UV 215-400 nm deuterium UV / VIS / NIR reflection / absorption 215-2500 nm Deuterium / Halogen UV / VIS / NIR Absorption 200-2500 nm Deuterium / Halogen UV / VIS 200-1000 nm xenon FTIR 2000-25000 nm Silicon carbide UV / VIS / IR Fluorescence Multiple narrowband emission LED, laser diode

[0051] The return laser detector 224 can detect a return laser signal from the target structure 122 in response to an excitation laser directed at the target structure 122. The excitation laser pulses can be emitted by the laser system 230. The return laser detector 224 can be positioned at the distal end of the optical fiber 234, near the fiber tip from which the excitation laser pulses are emitted. In one example, the excitation laser can be a chirped laser, also known as a frequency-controlled laser, which has a time-varying instantaneous frequency. The system 230 can include an optical splitter that divides the chirped laser into a first part, which is directed toward and irradiates the target structure 122, and a second part, which is held locally and does not reach the target structure 122.The laser signal reflected from the target, which responds to the first part radiating towards the target, can be detected and recombined interferometrically with the second part of the chirped laser. As described below, a coherence metric can be determined and used to estimate the distance between the fiber and the target.

[0052] The image signal received by the imaging sensor 222 and the back laser signal detected by the back laser detector 224 can be fed to the feedback analyzer 212. The feedback analyzer 212 comprises one or more of the following elements: a spectrometer 213, a target identification circuit 214, an optical coherence circuit 215, a fiber-to-target distance estimator 216, and a distance filter 217. The spectrometer 213 can determine one or more spectroscopic properties from the target's imaging signal, such as reflectivity, absorption index, and other spectral properties. Examples of the spectrometer 213 include a Fourier-transform infrared (FTIR) spectrometer, a Raman spectrometer, a UV-Vis reflection spectrometer, a UV-Vis-IR spectrometer, a fluorescence spectrometer, and the like. FTIR is a method used for routine, simple and fast material analysis.This technique has relatively good spatial resolution and provides information about the chemical composition of the material. Raman spectroscopy offers good accuracy in identifying hard and soft tissue components. As a high-resolution technique, it is also useful for determining the distribution of components within a target. UV-VIS reflection spectroscopy is a method that gathers information from the light reflected by an object, similar to the information provided by the eye or a color image from a high-resolution camera, but more quantitative and objective. Reflection spectroscopy provides information about the material because light reflection and absorption depend on its chemical composition and surface properties. This technique also makes it possible to obtain unique information about the surface and bulk properties of the sample.Reflectance spectroscopy can be a valuable technique for determining the composition of hard or soft tissue. Fluorescence spectroscopy is a type of electromagnetic spectroscopy that analyzes the fluorescence of a sample. It uses a beam of light, usually ultraviolet light, which excites a material compound, causing it to emit light, typically in the visible or infrared range. This method is suitable for analyzing some organic components, such as hard and soft tissue.

[0053] The target identification circuit 214 can identify the type or composition of the target structure 122 (or a specific part thereof) during the procedure in vivo using one or more spectroscopic properties determined by the spectrometer 213. In endoscopic laser therapy, it is desirable to identify the type and composition of the target and to apply appropriate laser energy only to the treatment target (e.g., cancerous tissue or a specific type of stone), while avoiding or reducing laser irradiation of tissue not to be treated (e.g., normal tissue). Conventional target identification generally requires taking a sample of the target for in vitro analysis.Continuous monitoring and automated in vivo tissue identification at the tip of the endoscope can advantageously reduce operating time and complexity, provide clinicians with more information for better treatment setup during the procedure, and improve therapy effectiveness. For example, in laser lithotripsy, where lasers are used to break up or atomize stones, the automated and in vivo detection of stones of a specific type (e.g., the chemical composition of a kidney, pancreatic, or gallbladder stone) and their differentiation from surrounding tissue would allow a clinician to adjust laser settings (e.g., power, exposure time, or firing angle) to ablate the target stone more effectively while avoiding irradiation of adjacent, non-treatable tissues. The jointly assigned U.S. patent application No.16 / 947,488 entitled “LASER FIBER-TO-TARGET DISTANCE CONTROL” describes exemplary procedures for identifying or classifying various target structures, such as different compositions of kidney stones (e.g., calcium oxalate stone (monohydrate), calcium oxalate stone (dihydrate), calcium phosphate stones, struvite stones, and uric acid stones) using spectroscopic data, the description of which is hereby incorporated in its entirety by reference.

[0054] The optical coherence circuit 215 can compute a coherence metric using the laser signal reflected from the target, which is interferometrically recombined with the second part of the chirped laser, split off from the chirped laser pulses. The optical coherence metric can include an interferogram and an analysis of the frequency components of the interferogram. The fiber-target distance estimator 216 can estimate, at least partially, the distance between a distal end of the optical fiber 234 and the target structure 122 (the "fiber-target distance") based on the coherence metric.The optical coherence-based distance measurement method is also known as frequency-modulated continuous wave (FMCW) scanning, which has been implemented in LiDAR (Light Detection and Ranging) scanners and has found widespread application in land management and planning, hazard assessment, forestry, agriculture, geological mapping, and surveying of watersheds and rivers. Fig. Figures 4A-4B are graphics illustrating the operating principle of the FMCW method for measuring fiber-to-target distance. Fig.Figure 4A conceptually illustrates a figure 412 of the time-frequency plot of the second section of the chirped laser (LO) split off from the chirped laser emitted by system 230, and a figure 414 of the returning laser signal (RX) in response to the first section of the chirped laser beaming onto the target structure 122. As a non-restrictive example, and as shown, the chirped laser LO is a linear chirp with an optical frequency (on the y-axis) that is a linear ramp function of time (on the x-axis). The returning laser signal RX also has a linear ramp function of frequency over time, very similar to that of the chirped laser LO, and is emitted after a time delay τ. DThe LO is detected after the chirped laser. If the return laser detector 224 is positioned at the distal end of the optical fiber 234 near the fiber tip from which the excitation laser pulses are emitted, the time delay τ corresponds to D the laser orbital period between the target structure 122 and the detector 224. In particular, τ depends D with the distance between fiber and target (R) and the speed of the laser (v) in the medium (e.g. fluid) of the laser path according to the relationship given by equation (1): τD=2R / ν

[0055] A heterodynic beat f beat , which represents a frequency difference between the two optical fields corresponding to the chirped laser LO and the returning laser signal RX at any given time t, can be determined using the time delay τ Dand the chirp rate (κ), which represents the rate of change of the instantaneous frequency (in Hertz per second), can be determined as follows: fbeat=κ*τD

[0056] By combining the above equations (1) and (2), the distance between fiber and target can be determined using the following equation (3): R=fbeat*ν / 2κ

[0057] Fig. Figure 4B shows a complete waveform distance profile 420, which was obtained using a Fourier transform of the heterodyne beat frequency f. beat was calculated. The profile shows the size (power) of f beat (dB, on a logarithmic scale on the y-axis) at various frequencies, which can be converted into distances on the x-axis. The peak power 422 of f beatThis corresponds to the distance R between the fiber and the target. In an example, estimator 216 can determine the heterodyne beat frequency f for the distance between the fiber and the target. beat measuring over time (i.e., the time-dependent frequency difference between the chirped laser LO and the returning laser signal RX), the Fourier transform of the heterodyne beat frequency f beat calculate and determine the distance between fiber and target 424, which corresponds to the peak amplitude (power) of f beat corresponds.

[0058] The fiber-to-target distance estimated using the FMCW method described above can be sensitive to the laser velocity (v) in the medium (e.g., fluid) within the target area. During endoscopic laser procedures, air bubbles can be generated by the laser energy and fluid irrigation and aspiration. Depending on the type of procedure and the target being treated, residues or stone fragments may also be present. These air bubbles, residues, stone fragments, and other particles or objects can create irregularities in the fluid space along the laser path, affecting the laser transmission velocity (v) and thus interfering with the fiber-to-target distance measurement. Fig. 5A and Fig. 5B illustrates examples of how air bubbles affect the measurement of the distance between the fiber and the target location. Fig.Figure 5A shows a laser signal emitted from a distal end 510 of the laser fiber and propagating through a uniform fluid environment without bubbles or other interfering objects (e.g., tissue residue, stone fragments) at a speed v. fluid , and reaches the target structure 122, which reflects at least part of the laser signal (the returning laser signal) traveling at velocity v fluid through the same uniform fluid medium to the laser tip. Fig. Figure 5B shows a laser signal emitted from the distal end 510 of the same laser fiber and traveling through a non-uniform fluid environment filled with air bubbles 520. Since water is denser than air, its refractive index is greater than that of air (~1.3 in water and ~1.0 in air). Compared to the speed of the laser in air c air of about 3*10 8 The speed of the laser in the fluid is meters per second (m / sec).fluid approximately 2.25*10 8 m / sec. If bubbles are present in the light path of the fluid, the laser's travel time is correspondingly longer than in a bubble-free fluid, which would lead to a greater (than actual) distance if one assumes that the entire light path is free of bubbles or other interfering objects. This is called overestimating the distance between the fiber and the target. Fig.Figure 6 illustrates an example of an overestimation of the fiber-target distance due to air bubbles or other interfering objects present in the fluid space of the light path. As shown, the fiber-target distance can be measured continuously or periodically over time using the optical coherence method described above. The resulting time series of distance measurements shows overestimations 610 of the fiber-target distance at the times when air bubbles or other interfering objects are present in the light path between the laser tip fiber and the target. These overestimations 610 are outliers that are larger than other distance measurements 620 performed in a bubble-free fluid.

[0059]

[0001] Referring to Fig. 2. The distance filter 217 can process a series of measurements of the distance between fiber and target acquired over time, as in Fig.Figure 6 illustrates how to filter out outliers, such as overestimations caused by air bubbles or other interfering objects in the fluid space along the light path. In one example, the distance filter 217 can use a statistical procedure to identify the outliers. Examples of statistical procedures include the Grubb test (when testing for a single outlier), the Tietjen-Moore test, or the Generalized Extreme Studentized Deviate (ESD) test. In another example, a distance threshold or acceptance range can be determined using an average (or other metrics of central tendency) of a plurality of distance measurements within a moving window and a tolerance margin, such as a fraction k of a variance or a standard deviation (SD) of the distance measurements within the moving window.Parameters such as the window length and the fraction k can be adjusted to ensure accurate distance measurements. In a non-restrictive example, the movable window has a length of 50 consecutive distance measurements. In a non-restrictive example, k takes values ​​between 0.25 and 0.5.

[0060] Each distance measurement generated by the Distance Estimator 216 between fiber and target can be reviewed against the distance threshold or the acceptance range and identified as either an outlier (e.g., an overestimate) if it exceeds the threshold (e.g., mean + 0.25*SD) or is outside the acceptance range (e.g., mean ± 0.25*SD), or otherwise as a qualified measurement. To improve the signal-to-noise ratio (SNR), a refined fiber-to-target distance can be calculated as the mean (or other central trend metrics) of a specified number (e.g., 30–50) of qualified distance measurements. The mean and variance (or SD) of the distance measurements can be updated as new distance measurements become available and are identified as qualified or outlier measurements. By excluding the outliers, only the qualified measurements are included in the update process.This enables a continuous, more accurate and more robust measurement of the distance between the fiber and the target.

[0061] The control unit 218 can be coupled to the feedback analyzer 212 via wired or wireless connections. The control unit 218 can control the laser system 230 according to one or more control algorithms described herein to control the laser power of the laser source 232. In some examples, the feedback analyzer 212 can continuously monitor the target structure 122 and continuously communicate with the control unit 218 to provide feedback control signals for adjusting the laser power, for example, by increasing or decreasing the pulse amplitude, pulse rate, power intensity, duration, frequency, pulse shape, exposure time, and other laser irradiation parameters. The control unit 218 can maintain the laser system 230 in a specific state (at a specific power) until a change in the feedback is detected.For example, if the target identification circuit 214 detects a different target type or composition based on the spectroscopic properties of the spectrometer 213, the control unit 218 can adjust the laser power of the laser source 232. In an example involving a kidney stone with a hard surface (composition one) and a softer core (composition two), the continuous tissue composition analysis by the target identification allows the use of an initial higher laser power to atomize the hard surface of the kidney stone. After atomization, the system automatically switches, or upon user confirmation, to a lower laser power to ablate the soft core of the stone. Alternatively, in some examples, the control unit 218 can adjust the laser power manually in a command mode.In this case, the control unit 218 can display the current laser power and information about the identified target type or target composition to a user (e.g., a surgeon or endoscopist) via a user interface and recommend to the user to adjust the laser power to achieve the desired therapeutic effect on the target structure 122.

[0062] In addition to target identification information (e.g., target type or target composition), the control unit 218 can control the laser system 230 to continue delivering laser energy to the target structure 122 based on the estimated distance between the fiber and the target. For example, if the target structure 122 is identified as the intended treatment type (e.g., a specific type of soft tissue or a specific type of stone) and if the distance between the fiber and the target (d) meets a condition (e.g., is below a threshold dth or is within a specific laser firing range), the laser pulses can be delivered to the target structure 122. However, if the target structure 122 is not within the laser firing range (e.g., d > d), the laser pulses will not be delivered. thThe control unit 218 can generate a control signal to temporarily "lock" the laser source 232, preventing laser pulses from being emitted to the target until the target structure 122 is within the laser firing range. The estimated distance between the fiber and the target, as well as an indication that the target structure 122 is outside the laser firing range (d > d), are also displayed. th ), can be displayed to the user on a user interface. The user can adjust the optical fiber 234, for example by repositioning the distal end of the optical fiber 234 to get closer to the target.

[0063] In some examples, the control unit 218 can generate a control signal to a robotic arrangement, such as an actuator 260, to robotically adjust the position or orientation of the distal end of the optical fiber 234 relative to the target structure 122. For example, in response to the control signal from the control unit 218, the actuator 260 can automatically move the optical fiber forward or backward or change the orientation (e.g., a target angle) of the distal end of the optical fiber 234 relative to the target structure 122. In one example, the control unit 218 can adjust the position or orientation of the distal end of the optical fiber based on the identified target type or composition.A desired or optimal distance or range for firing the laser at the target can depend on several factors, including the target type or composition, the target position and surrounding anatomy, the laser settings, the type of procedure, and the desired tissue effect. As described above, the laser power can be adjusted manually or automatically based on the target type or composition, allowing different parts of the target (e.g., the surface and core of a stone structure, each with a different composition) to be treated with different laser powers. In addition to or as an alternative to adjusting the laser power, in some cases the position or orientation of the distal end of the optical fiber can be adjusted based on the target type or composition.In an example of laser lithotripsy, while the target identification circuit 214 continuously analyzes the target type and composition, the control unit 218 can control the actuator 260 so that the distal end of the optical fiber 234 is moved closer to a kidney stone target when a hard surface of the target is identified, in order to better atomize the stone surface. In response to the identification of a soft core of the target stone, the control unit 218 controls the actuator 260 so that it retracts the distal end of the optical fiber 234 further away from the kidney stone target.

[0064] The user interface 250 can communicate operationally with the feedback control system 210. The user interface 250 can include a display unit to show information such as conditions at the operating site, like images, pressure, or other information acquired by the sensors 220; information generated by the feedback analyzer 212, including target identification and the estimated distance between the fiber and the target; and current device settings, such as the laser power setting. The display unit can show UI elements, including visual elements, warning messages, tactile feedback, or any combination thereof. In some examples, the user interface 250 can generate a warning message if the distance between the fiber and the target exceeds a threshold or a specific range.The warning message can be presented in an acoustic, visual, tactile, or otherwise human-perceived format. The user interface 250 can include one or more input units to receive user programming for various components of the laser surgery system 200, such as parameter values ​​used to identify the target type or composition, estimate the distance between the fiber and the target, and adjust the laser power. In some examples, the display unit can generate recommendations for adjusting the position or orientation of the distal end of the optical fiber 234, or for adjusting the laser power or other system parameters. A user can use the one or more input units to confirm, reject, or modify the recommended adjustments.

[0065] Fig.Figure 3 shows an example of a feedback-controlled endoscopic laser surgery system 300 with automatic measurement of the distance between the fiber and the target and optical fiber position control. System 300 can be an example of an implementation of the laser surgery system 200.

[0066] The system 300 can comprise an endoscope 301 integrated with a feedback control system 310, a laser system comprising a laser source 332 and an optical fiber 334, and a robotic arrangement such as an actuator. The endoscope 301 has a proximal section and an elongated distal section designed to be inserted into a patient's surgical site during an endoscopic procedure. The endoscope 301 can be used for the visual inspection or treatment of soft (e.g., non-calcified) or hard (e.g., calcified) targets, including, but not limited to, stone structures. As described in Fig.As shown in Figure 3, the endoscope 301 can include or provide visualization and illumination optics, such as a visualization light path 360 and an illumination light path 350, each extending longitudinally along the elongated body of the endoscope 301. An eyepiece, camera, or image display can be provided on or connected to the optical path 360 to allow the user or machine to visualize a target area at or near a distal end of the endoscope 301. The target area can be illuminated by light 370, provided, for example, by an illumination light source 324 at a proximal end of the illumination optical path 350 and emitted from a distal end of the illumination optical path 350. The light source 324 can, for example, include a xenon lamp, a light-emitting diode (LED), a laser diode, or any combination thereof.In one example, the light source 324 can comprise two or more light sources that emit light with different illumination characteristics, known as illumination modes. For instance, the illumination modes might include a white light illumination mode or a specialized light illumination mode such as a narrowband imaging mode, an autofluorescence imaging mode, or an infrared imaging mode. A specialized light illumination mode might, for example, concentrate and intensify specific wavelengths of light, resulting in improved visualization of tissue or other structures at the surgical site.

[0067] The endoscopic laser surgery system 300 can contain or be coupled to the laser source 332, which may be, for example, the first laser source 106 or the second laser source 116 in Fig. 1 or the laser source 232 in Fig.2. The laser source 332 can be mechanically and optically connected to the optical fiber 334, which can comprise a single optical fiber or a bundle of optical fibers. The optical fiber 334, which is an embodiment of the first optical path 108 or the second optical path 118 in Fig. 1 or the optical fiber 234 in Fig. 2 can be inserted through a proximal access port of the endoscope 301 and extend within a working channel or other longitudinal passage or lumen of the endoscope 301 or a similar instrument.

[0068] In some examples, the laser source 332 can be a first laser source (such as the one in Fig. 1 first laser source 106) shown, which is configured to generate therapeutic laser pulses (also called a treatment beam) for surgical removal or extraction of tissue or for ablating a stone, and a second laser source (such as the one shown in Fig. 1. A second laser source (116) shown is used to generate non-therapeutic laser pulses, such as excitation laser pulses, which are used to estimate the distance between the fiber and the target. The therapeutic laser pulses and the non-therapeutic laser pulses can be directed to the target via the same or different optical paths.

[0069] The endoscopic laser surgery system 300 can include a camera or an imaging device 325. The camera or imaging device 325 can include an imaging sensor (such as the image sensor 222 in Fig. 2) comprising, which can generate an image signal 365 of the target in response to electromagnetic radiation (e.g., illumination light 370) from the target at or near the site of operation. The camera or imaging device 325 may be a CCD or CMOS camera or a laser scanner. As in Fig.As shown in Figure 3, the target structure 122 is located within the field of view of the camera or imaging device 325, so that the camera or imaging device 325 can detect the signal reflected by the target structure 122 in response to the electromagnetic radiation and generate an imaging signal 365 of the target structure 122. The imaging signal 365 can be transmitted to the feedback control system 310 (which is an example of the feedback control system 210) via the optical path 360 or alternatively via the optical fiber 334. In one example, the optical fiber 334 can simultaneously transmit the laser pulses (including the chirped laser 383 and the returning laser signal 385) and the reflected imaging signal 365. The feedback control system 310 can include a feedback analyzer 312 and a control unit 318.In one example, the imaging signal can pass through an optical splitter before reaching the feedback analyzer 312. The feedback analyzer 312, which is an example of the feedback analyzer 212 in . Fig. 2 can include a spectrometer capable of generating one or more spectroscopic properties from the imaging data. The feedback analyzer 312 can identify the target as a tissue type or a stone with a different composition based on the one or more spectroscopic properties, as described above in relation to Fig. 2 described.

[0070] The feedback analyzer 312 can calculate or estimate a fiber-to-target distance between a distal end 336 of the optical fiber 334 and the target structure 122. In one example, the fiber-to-target distance can be estimated using an FMCW method, where a coherence metric can be derived using a chirped laser 383 emitted from the laser source 332 and a returning laser signal 385 in response to a portion of the chirped laser beaming onto the target structure 122, as described above. Fig.2 and 4A-4B are described. The control unit 318 can generate a control signal to the laser source 332 to adjust an output setting for the therapeutic laser pulse. The adjustment of the therapeutic laser output setting can be based, at least in part, on the identified target type or composition. In some examples, the adjustment of the therapeutic laser output setting can also be based on the determined fiber-to-target distance. For example, the control unit 318 can temporarily "lock out" the laser source 332 to prevent it from emitting laser pulses when the estimated fiber-to-target distance exceeds a threshold range.

[0071] The control unit 318 can additionally or alternatively generate a control signal to a robotic arrangement to adjust the position or orientation of the distal end 336 of the optical fiber 334. The robotic arrangement, such as the actuator 338, can be coupled to a section of the optical fiber 334 and can be electrically connected to the control unit 318. For example, the actuator 338 can be located at or near the distal end of the endoscope 301.The actuator 338 may comprise one or more of the following elements: an electromagnetic element, an electrostatic element, a piezoelectric element, or another actuating element to actuate or otherwise enable the longitudinal or rotational positioning of the distal end 336 of the optical fiber 334 with respect to the working channel or other longitudinal passage of the endoscope 301, or with respect to another reference location for which the endoscope 301 may serve as a reference frame. At least partially based on the identified target type or composition, the control unit 318 may activate the actuator 338 to adjust the position or orientation of a distal end 336 of the optical fiber 334, for example, by adjusting the longitudinal position by moving forward or retracting the distal end 336 to increase or decrease the distance to the target structure 122.to reduce the size, or to adjust the rotational position by steering the distal end 336 to increase or decrease the target angle relative to the target structure 122. Such an adjustment of the position or orientation of a distal end of the optical fiber can improve the effectiveness of the laser treatment while conserving laser energy.

[0072] Fig. Figure 7 is a flowchart illustrating an example procedure 700 for providing feedback control of a surgical laser system to provide adjustable laser treatment of a target using feedback including fiber distance measurements to the target. The procedure 700 can be found in the Fig. 2 laser surgery system 200 shown or the one in Fig.The feedback-controlled endoscopic laser surgery system 300, as shown in Figure 3, is implemented and executed and is used for laser lithotripsy of kidney stones, bezoars, gallstones, and other stone structures, or for laser incision or vaporization of soft tissue, for example, during an endoscopic procedure. Although the processes of Procedure 800 are depicted in a flowchart, they need not be performed in a specific order. In various examples, some of the processes may be performed in a different sequence than shown here.

[0073] At 710, a chirped laser can be directed at a target structure, and a returning laser signal can be received in response to the target being irradiated with the chirped laser. The chirped laser can be emitted from a laser source through an optical fiber of a laser system, such as the Laser Surgery System 200 or the Feedback Controlled Endoscopic Laser Surgery System 300. The chirped laser, also known as a frequency-controlled laser, has a time-varying instantaneous frequency. The chirped laser can be split into a first part that travels through the optical fiber to the target structure and a second part that remains local and does not travel to the target structure. A returning laser signal can be detected in response to the first part of the chirped laser beam directed at the target. The first part of the chirped laser is also referred to as the chirped laser excitation.In one example, the chirped laser is a linear chirp, so the optical frequency of the chirped laser is a linear ramp function of time. As in the example above regarding . Fig. As described in 4A, the returning laser signal can have a similar time-frequency profile (e.g., a linear ramp function of frequency over time) to the chirped laser directed at the target, except that the returning laser is essentially a time-delayed version of the exciting chirped laser, the time delay being related to the orbital period between the distal end of the laser fiber and the target structure.

[0074] At 720, an optical coherence metric can be generated between the chirp laser excitation and the returning laser signal. This optical coherence metric correlates with the chirp laser's orbital period between the distal end of the optical fiber and the target structure. At 730, using this coherence metric, a distance between the distal end of the optical fiber and the target structure (the "fiber-to-target distance") can be determined. Such an optical coherence-based distance measurement is also known as the frequency-modulated continuous wave (FMCW) method. As above regarding Fig. As described in 4B, the FMCW method includes detecting a heterodyne beat fbeat, which represents a frequency difference between the two optical fields corresponding to the chirp laser excitation and the returning laser signal at any given time, and identifying the peak amplitude (power) of fbeat. beatin a frequency space (e.g., a Fourier transform of the heterodynamic beat f) beat The distance between the fiber and the target can be determined as the frequency-converted distance, which corresponds to the peak amplitude (power) of f. beat corresponds.

[0075] At 740, a time series of fiber-to-target distance measurements obtained during a continuous or periodic distance measurement using the optical coherence described above can be filtered, for example, using the method described in Fig. 2 distance filter 217 shown. One or more outlier measurements can be identified from the fiber-to-target distance measurements. The outliers, as above in relation to Fig.As described in section 5B, overestimations can include those caused by air bubbles generated by the laser energy and fluid wetting and aspiration, tissue residue, stone fragments, and other particles or objects. These air bubbles and interfering objects can introduce inconsistencies in the fluid space and affect the laser transmission velocity, potentially leading to overestimations of the fiber-to-target distance. A statistical method can be used to identify outlier measurements and filter them out of the fiber-to-target distance data. Examples of statistical methods include the Grubb test (when checking for a single outlier), the Tietjen-Moore test, or the Generalized Extreme Studentized Deviate (ESD) test.In one example, outlier measurements can be identified based on the average and variance or standard deviation (SD) of the majority of fiber-to-target distance measurements. In another example, a distance threshold or acceptance range can be determined based on a moving average (mean or other central tendency) of a large number of distance measurements within a moving window and a tolerance margin, such as a fraction k of the SD of the distance measurements within the moving window. Each new distance measurement can be checked against the distance threshold or acceptance range and either identified as an outlier if it exceeds the threshold or is outside the acceptance range, or otherwise considered a qualifying measurement.A refined distance between fiber and target can be calculated as the average of a specific number of qualified distance measurements.

[0076] At 750, a control signal can be generated for the surgical laser system to adjust the position or orientation of the distal end of the optical fiber relative to the target, at least partially, based on the determined distance between the fiber and the target. This adjustment can be performed using a robotic setup, such as the one described in Fig.Actuator 260 shown in Figure 2 can robotically move the optical fiber forward or backward or change the aiming angle of the distal end of the optical fiber relative to the target structure. For example, if the fiber-to-target measurement exceeds a distance threshold, the optical fiber can be robotically manipulated to move the distal end closer to the target. Additionally or alternatively, the position or orientation of the distal end of the optical fiber relative to the target object can be adjusted based on the target object type or composition, which can be identified at least partially from the target object's spectroscopic properties, for example, using the target object identification circuit 214, as described above. Fig. 2 described.

[0077] At 760, laser treatment of the target structure can be performed according to a laser power setting. The laser power setting includes one or more laser power parameters such as pulse amplitude, pulse rate, power intensity, duration, frequency, pulse shape, exposure time, and other laser irradiation parameters. The laser power setting can be adjusted based on the target type or composition, which can be identified, at least in part, by its spectroscopic properties, as described above. Fig.2 described. Additionally or alternatively, the laser power setting can be adjusted based on the measurement of the distance between the fiber and the target. For example, if the target structure is identified as an intended treatment target type (e.g., a specific soft tissue or stone structure) and if the distance between the fiber and the target meets a certain condition (e.g., falls below a distance threshold or is within a specific laser firing range), the laser pulses can be delivered to the target structure. If the target structure is not within the laser's range, the laser source can be temporarily "locked out" so that no laser pulses are delivered to the target until the target structure is within the laser firing range.In some examples, the laser set settings, target type or composition identification, and fiber-to-target distance measurement can be displayed to a user on a user interface. The user can then, for example, accept, reject, or modify the laser set settings via the interface before they are applied to the laser system to initiate or adjust the laser treatment of the target.

[0078] Fig. Figure 8 shows a general block diagram of an example machine 800 on which one or more of the techniques (e.g., methodologies) described herein can be executed. Parts of this description may apply to the computing framework of various parts of the laser surgery system 200 or the endoscopic laser surgery system 300.

[0079] In alternative embodiments, the Machine 800 can operate as a standalone device or be connected (e.g., networked) to other machines. In a networked deployment, the Machine 800 can operate as a server machine, a client machine, or both in server-client network environments. For example, the Machine 800 can function as a peer machine in a peer-to-peer (P2P) network environment (or other distributed network environment). The Machine 800 can be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web device, a network router, a switch or bridge, or any other machine capable of executing instructions (sequentially or otherwise) that specify the actions to be performed by that machine.Although only a single computer is depicted, the term "computer" also includes any collection of computers that individually or collectively execute a set (or multiple sets) of instructions to perform one or more of the methods described herein, such as cloud computing, software as a service (SaaS), or other computer cluster configurations.

[0080] Examples, as described here, can include or operate logic or a set of components or mechanisms. Circuit sets are a collection of circuits implemented in tangible units that include hardware (e.g., simple circuits, gates, logic, etc.). Membership in a circuit set can be flexible over time and due to the variability of the underlying hardware. Circuit sets include elements that, alone or in combination, can perform specific operations when in operation. In one example, the hardware of the circuit set may be immutably designed to perform a specific operation (e.g., hardwired). In another example, the hardware of the circuit set may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.), including a computer-readable medium that is physically modified (e.g.,(magnetic, electrical, movable arrangement of unchanging mass particles, etc.) to encode commands for the specific operation. By connecting the physical components, the underlying electrical properties of a hardware component are changed, for example, from an insulator to a conductor or vice versa. The commands allow the embedded hardware (e.g., the execution units or a loading mechanism) to create members of the circuit set within the hardware via the variable connections to execute parts of the specific operation when in operation. Accordingly, the computer-readable medium is communicatively connected to the other components of the circuit set member when the device is in operation. In one example, each of the physical components can be used in more than one element of more than one circuit set.For example, execution units can be used in operation at one time in a first circuit of a first circuit set and reused at another time by a second circuit in the first circuit set or by a third circuit in a second circuit set.

[0081] The machine (e.g., a computer system) 800 may comprise a hardware processor 802 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), main memory 804, and static memory 806, some or all of which may communicate with each other via a connection (e.g., a bus) 808. The machine 800 may further comprise a display unit 810 (e.g., a raster display, a vector display, a holographic display, etc.), an alphanumeric input device 812 (e.g., a keyboard), and a user interface (UI) navigation device 814 (e.g., a mouse). In an example, the display unit 810, the input device 812, and the UI navigation device 814 may be a touchscreen display. The machine 800 can additionally include a storage device (e.g. a drive unit) 816, a signal generation device 818 (e.g.The machine 800 may include a loudspeaker, a network interface device 820, and one or more sensors 821, such as a GPS (Global Positioning System) sensor, a compass, an accelerometer, or other sensors. The machine 800 may include an output control unit 828, such as a serial (e.g., Universal Serial Bus (USB)), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection for communicating with or controlling one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0082] The storage device 816 can comprise a machine-readable medium 822 on which one or more sets of data structures or instructions 824 (e.g., software) are stored, embodying or utilizing one or more of the techniques or functions described herein. The instructions 824 may also be stored, in whole or in part, in the main memory 804, the static memory 806, or the hardware processor 802 during their execution by the machine 800. In an example, any one or any combination of the hardware processor 802, the main memory 804, the static memory 806, or the storage device 816 can constitute a machine-readable medium.

[0083] While the machine-readable medium 822 is represented as a single medium, the term "machine-readable medium" can encompass a single medium or multiple media (e.g., a centralized or distributed database and / or associated caches and servers) configured to store the one or more instructions 824.

[0084] The term “machine-readable medium” can encompass any medium capable of storing, encoding, or transmitting instructions for execution by the Machine 800 that cause the Machine 800 to execute one or more of the techniques of this disclosure, or capable of storing, encoding, or transmitting data structures used by or associated with such instructions. Examples of non-restrictive machine-readable media include solid-state storage media as well as optical and magnetic media. In one example, a mass-based machine-readable medium comprises a machine-readable medium with a plurality of particles having an unchanging (e.g., rest) mass. Accordingly, mass-based machine-readable media do not include transient propagation signals.Specific examples of mass-based machine-readable media can include non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EPSOM)) and flash memory devices; magnetic disks, such as internal hard disks and removable media; magneto-optical disks; and CD-ROM and DVD-ROM disks.

[0085] The instructions 824 can also be transmitted or received via a communication network 826 using a transmission medium via the network interface device 820 using any one of a number of transmission protocols (e.g., Frame Relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), etc.). Examples of communication networks include local area networks (LANs), wide area networks (WANs), packet data networks (e.g., the Internet), cellular networks (e.g., mobile networks), POTS (Plain Old Telephone Service) networks, and wireless data networks (e.g., the IEEE 802.11 family of standards, known as WiFi®, the IEEE 802.16 family of standards, known as WiMAX®, the IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks, and others). In one example, the 820 network interface device can have one or more physical ports (e.g.,The Network Interface Device 820 may include Ethernet, coaxial, or telephone jacks, or one or more antennas for connecting to the Communication Network 826. For example, the Network Interface Device 820 may include multiple antennas for wireless communication using at least one of the following techniques: Single-Input Multiple-Output (SIMO), Multiple-Input Multiple-Output (MIMO), or Multiple-Input Single-Output (MISO). The term "transmission medium" is to be understood as including any intangible medium capable of storing, encoding, or transmitting instructions for execution by the Machine 800, and includes digital or analog communication signals or other intangible media to facilitate communication by such software. Additional remarks

[0086] The foregoing detailed description contains references to the accompanying drawings, which form part of the detailed description. The drawings illustrate specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as "examples." Such examples may include additional elements beyond those shown or described. However, the present inventor also considers examples in which only the elements shown or described are provided. Furthermore, the inventor also considers examples that use any combination or permutation of the elements shown or described (or one or more aspects thereof), either in relation to a particular example (or one or more aspects thereof) or in relation to other examples shown or described herein (or one or more aspects thereof).

[0087] In this document, the terms "a" or "an" are used, as is customary in patent documents, to include one or more instances, irrespective of other instances or uses of "at least one" or "one or more". In this document, the term "or" is used to indicate a non-exclusive combination, so that "A or B" includes "A but not B", "B but not A", and "A and B" unless otherwise indicated. In this document, the terms "including" and "in which" are used as simple linguistic equivalents of the respective terms "comprising" and "in which". Furthermore, in the following claims, the terms "including" and "comprising" are open, i.e.,A system, device, article, composition, formulation, or method that includes further elements in addition to those listed in a claim following such term remains within the scope of that claim. Furthermore, in the following claims, the terms "first," "second," and "third," etc., are used merely as designations and are not intended to impose any numerical requirements on their objects.

[0088] The above description is for illustrative purposes only and is not limiting. For example, the examples described above (or one or more aspects thereof) may be used in combination. Other embodiments may also be used, for example, by a person skilled in the art after reviewing the above description. The summary is intended to enable the reader to quickly assess the nature of the technical disclosure. It is presented with the understanding that it is not intended to be used for interpreting or limiting the scope or meaning of the claims. Furthermore, various features may be summarized in the above detailed description to streamline the disclosure. This should not be interpreted as meaning that an unclaimed disclosed feature is essential to a claim.Rather, the inventive subject matter may consist of fewer than all features of a particular disclosed embodiment. Therefore, the following claims are hereby included in the detailed description as examples or embodiments, each claim constituting a separate embodiment, and it is intended that such embodiments may be combined with one another in various combinations or permutations. The scope of the invention should be determined by reference to the appended claims together with the full scope of the equivalents to which such claims are entitled. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 16 / 947,488

[0053]

Claims

A surgical laser system comprising: a laser system configured to generate laser pulses and deliver them via an optical fiber to a target in a patient's anatomical environment; and a control unit, including a feedback analysis circuit, configured to: receive a returning laser signal from the target in response to a chirp laser emitted by the surgical laser system and directed at the target; generate an optical coherence metric using at least a portion of the chirped laser and the returning laser signal, wherein the optical coherence metric is correlated with the laser orbital period between a distal end of the optical fiber and the target;and a fiber-to-target distance between the distal end of the optical fiber and the target is determined using the optical coherence metric, wherein the control unit is configured to generate a control signal to adjust a position or orientation of the distal end of the optical fiber relative to the target, at least partially, based on the determined fiber-to-target distance. The surgical laser system according to claim 1, wherein the feedback analyzer circuit is configured to further determine the fiber-to-target distance based on a chirp rate of the chirped laser. The surgical laser system according to one of claims 1-2, wherein the control unit is configured to adjust a surgical laser power setting of the surgical laser system at least partially on the basis of the determined distance between fiber and target object. The surgical laser system according to any one of claims 1 to 3, further comprising a light source configured to direct electromagnetic radiation onto the target, wherein the feedback analyzer circuit is configured to: detect a reflected image signal from the target in response to the electromagnetic radiation at the target; determine a spectroscopic property of the target from the reflected imaging signal; and identify a target type or target composition at least partially based on the determined spectroscopic property of the target. The surgical laser system according to claim 4, wherein the control unit is configured to further generate the control signal for adjusting the position or orientation of the distal end of the optical fiber relative to the target based on the identified target type or identified target composition. The surgical laser system according to one of claims 4-5, wherein the control unit is configured to adjust a surgical laser power setting of the surgical laser system at least partially on the basis of the identified target type or identified target composition. The surgical laser system according to one of claims 4 to 6, wherein the optical fiber is configured to simultaneously direct the laser pulses and the reflected image signal. The surgical laser system according to any one of claims 1 to 7, wherein the control unit is configured to supply the control signal to a robot arrangement coupled with the optical fiber in order to robotically adjust the position or orientation of the distal end of the optical fiber relative to the target. The surgical laser system according to any one of claims 1 to 8, comprising a user interface configured to display to a user the determined distance between fiber and target as well as a recommendation to adjust the position or orientation of the distal end of the optical fiber relative to the target. The surgical laser system according to any one of claims 1 to 9, wherein the target comprises a tissue target, wherein the surgical laser system is configured to generate and deliver the laser pulses to treat the tissue target. The surgical laser system according to any one of claims 1 to 10, wherein the target comprises a stone target, wherein the surgical laser system is configured to generate and deliver the laser pulses to ablate or fragment the stone. Surgical laser system according to one of claims 1 to 11, comprising an endoscope containing or coupled to the surgical laser system, wherein the endoscope comprises a longitudinal channel for passing the optical fiber. The surgical laser system according to any one of claims 1 to 12, wherein the feedback analyzer circuit is further configured to: identify one or more outlier measurements from a plurality of fiber-to-target distance measurements generated over time; filter the plurality of fiber-to-target distance measurements to exclude the identified outlier measurement(s); and determine the fiber-to-target distance using the filtered plurality of fiber-to-target distance measurements. The surgical laser system according to claim 13, wherein the feedback analyzer circuit is configured to identify one or more outlier measurements based on an average and variance of the majority of fiber distance measurements to the target. A method for feedback control of a surgical laser system during laser surgery on a patient, comprising: directing a chirped laser through an optical fiber of the surgical laser system toward a target in an anatomical environment of the patient and receiving a returning laser signal from the target in response to the irradiation of the target with the chirped laser; generating an optical coherence metric using at least a portion of the chirped laser and the reflected laser signal, wherein the optical coherence metric is correlated with the laser orbital period between a distal end of the optical fiber and the target; determining a fiber-to-target distance between the distal end of the optical fiber and the target using the optical coherence metric;and adjusting the position or orientation of the distal end of the optical fiber relative to the target, at least partially based on the determined fiber-to-target distance. Method according to claim 15, wherein the determination of the distance between fiber and target object is further based on a chirp rate of the chirped laser. Method according to one of claims 15 to 16, further comprising setting a surgical laser power setting of the surgical laser system, which is based at least partially on the determined distance between fiber and target. The method according to any one of claims 15 to 17, further comprising: directing electromagnetic radiation at the target; receiving a reflected image signal from the target in response to the electromagnetic radiation; determining a spectroscopic property of the target from the reflected image signal; and identifying a target type or target composition, at least partially based on the determined spectroscopic property of the target. Method according to claim 18, wherein the adjustment of the position or orientation of the distal end of the optical fiber relative to the target object is further based on the identified target object type or composition. Method according to one of claims 18 to 19, further comprising setting a surgical laser power setting of the surgical laser system, which is based at least partially on the identified target type or target composition. Method according to any one of claims 15 to 20, wherein the target comprises a tissue target or a stone target. Method according to any one of claims 15 to 21, comprising providing a control signal to a robot arrangement coupled to the optical fiber in order to robotically adjust the position or orientation of the distal end of the optical fiber relative to the target. Method according to any one of claims 15 to 23, comprising displaying the determined distance between fiber and target as well as a recommendation for adjusting the position or orientation of the distal end of the optical fiber relative to the target on a user interface. A method according to any one of claims 15 to 23, comprising: identifying one or more outlier measurements from a plurality of fiber-to-target distance measurements generated over time, each based on appropriate optical coherence metrics; filtering the plurality of fiber-to-target distance measurements to exclude the identified outlier measurement(s); and determining the fiber-to-target distance using the filtered plurality of fiber-to-target distance measurements. Method according to claim 24, wherein the identification of the one or more outlier measurements is based on an average and a variance of the majority of fiber distance measurements to the target.

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