Laser emission modulation for the treatment of kidney stones

Abstract

A laser-based system and method for treating kidney stones. The system may include a laser configured to emit pulsed laser energy and a controller configured to control the laser. The laser may be modulated to operate in one of the following modes of operation: pulverization, fragmentation, or reduced backward movement. One or more of these modes of operation may include pulses composed of subpulses.

Description

Technical Field

[0001] (Cross - reference to related art) This application claims priority to U.S. Provisional Application No. 63 / 440191, filed on January 20, 2023, entitled "LASER EMISSION MODULATION FOR TREATMENT OF HARD TISSUE", the content of which is hereby incorporated by reference in its entirety.

[0002] This technical field generally relates to the laser treatment of kidney stones, and more specifically, to modulated pulsed laser energy in the treatment of kidney stones.

Background Art

[0003] Kidney stones are a common condition that is estimated to affect 12% of the world's population. Most patients can pass the stones naturally, but the condition can be severe enough to require medical intervention. Extreme pain, nausea, vomiting, infection, obstruction of urine flow, and loss of kidney function can ensue. Laser lithotripsy is a method of treating kidney stones that uses light energy directed by an optical fiber to break the stones into smaller pieces that can pass naturally.

[0004] Optimal targeting of kidney stones, such as stones, and minimizing the risk of accidental damage to surrounding healthy soft tissue are two major problems in laser lithotripsy. Therefore, technical solutions are needed to address both of these problems by optimizing the temporal structure of the laser output.

[0005] Until recently, related laser sources (e.g., Ho:YAG lasers) had very limited ability to be modulated. However, the emergence of newer laser sources (e.g., diode - laser - pumped Tm fiber lasers and Tm:YAG lasers) offers the possibility of modulating lasers over a wider range of outputs.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The embodiments and models relate to methods and systems for modulating laser emission for treating kidney stones using pulsed laser energy. [Means for solving the problem]

[0007] According to an exemplary embodiment, a laser system for treating kidney stones is provided, comprising: a laser configured to emit pulsed laser energy having a wavelength in the range of 1.85 to 2.2 micrometers (μm); and a controller configured to control the laser so that the pulsed laser energy is emitted as a sequence of subpulse groups separated in time by a pulse repetition interval, wherein each subpulse group includes at least two subpulses separated in time by a subpulse interval in the range of 0 to 10 milliseconds (ms), each subpulse in the subpulse group having a pulse duration in the range of 0.001 to 5 ms, each subpulse in the subpulse group having an energy in the range of 0.001 to 1 joule (J), and the pulse repetition interval being in the range of 1 to 1000 ms.

[0008] According to another exemplary embodiment, a method for treating a gallstone is provided, comprising: generating pulsed laser energy having a wavelength in the range of 1.85 to 2.2 micrometers (μm); emitting the pulsed laser energy as a sequence of subpulse groups temporally separated by a pulse repetition interval, each subpulse group comprising at least two subpulses temporally separated by a subpulse interval in the range of 0 to 10 milliseconds (ms); each subpulse in the subpulse group having a pulse duration in the range of 0.001 to 5 milliseconds (ms); each subpulse in the subpulse group having an energy in the range of 0.001 to 1 joule (J); and emitting the pulsed laser beam to a treatment area of ​​the gallstone.

[0009] In one example, the subpulse group contains 2 to 1000 subpulses. In another example, the subpulse group contains 2 to 100 subpulses. In yet another example, the subpulse group contains 2 to 10 subpulses.

[0010] In one example, the total energy of the subpulse group is in the range of 0.2 to 5 J. In another example, the total energy of the subpulse group is in the range of 0.5 to 2 J.

[0011] In one example, the energy of each subpulse is in the range of 0.01 to 1 J. In another example, the energy of each subpulse is in the range of 0.2 to 1 J.

[0012] In one example, the subpulse interval is in the range of 0.01 to 5 ms. In another example, the subpulse interval is in the range of 0.01 to 1 ms.

[0013] In one example, the duration of each subpulse is in the range of 0.1 to 1 ms.

[0014] In one example, the pulsed laser energy has an average power in the range of 2 to 120 watts (W). In another example, the average power is in the range of 2 to 40 watts. In yet another example, the average power is in the range of 5 to 40 watts.

[0015] In one example, the pulse repetition rate within a subpulse group is in the range of 0.5 to 500 Hz.

[0016] In one example, the peak power of the subpulses in a subpulse group is in the range of 250 to 20,000 W. In another example, the peak power of the subpulses in a subpulse group is in the range of 500 to 5,000 W.

[0017] In one example, at least one subpulse in a group of subpulses has a pulse shape such that the power of at least one subpulse increases monotonically from the beginning to the end of the subpulse.

[0018] For example, the laser could be a thulium fiber laser, a thulium solid-state laser, or a holmium solid-state laser.

[0019] In one example, the size of a calculus fragment after exposure to a pulsed laser beam is less than 1 mm in maximum cross-sectional dimensions.

[0020] According to another exemplary embodiment, a laser system for treating gallstones is provided, comprising: a laser configured to emit pulsed laser energy having a wavelength in the range of 1.85 to 2.2 micrometers (μm); and a controller configured to control the laser such that each pulse of the emitted pulsed laser energy includes two subpulse groups separated in time by a subpulse group interval, wherein each subpulse group includes at least two subpulses separated in time by a subpulse interval in the range of 0 to 1 millisecond (ms); the first subpulse group has sufficient total energy, total pulse length, and average power to generate mechanical stress in the target gallstone; the second subpulse group has sufficient total energy, total pulse length, and average power to generate thermomechanical shock in the target gallstone; the total energy of the two subpulse groups is in the range of 2 to 70 joules (J); and the repetition rate of the two subpulse groups is in the range of 0.5 to 10 hertz (Hz).

[0021] According to another exemplary embodiment, a method for treating a calculus, comprising generating pulsed laser energy having a wavelength in the range of 1.85 to 2.2 micrometers (μm), and emitting the pulsed laser energy as two sub-pulse groups temporally separated by a sub-pulse interval in the range of 0 to 1 millisecond (ms), wherein the two sub-pulse groups are configured such that the first sub-pulse group has a total energy, total pulse length, and average power sufficient to generate mechanical stress in the target calculus, and the second sub-pulse group has a total energy, total pulse length, and average power sufficient to generate a thermo-mechanical shock in the target calculus, and the total energy of the two sub-pulse groups is in the range of 2 to 70 joules (J), and the repetition rate of the two sub-pulse groups is in the range of 0.5 to 10 hertz (Hz), and directing the pulsed laser beam at the target calculus.

[0022] In one example, the size of the fragments of the target calculus after exposure to the pulsed laser energy is at least 1 mm in the maximum cross-sectional dimension. In another example, the size of the fragments of the target calculus after exposure to the pulsed laser energy is in the range of 1 to 5 mm in the maximum cross-sectional dimension. In another example, the size of the fragments of the target calculus after exposure to the pulsed laser energy is in the range of 1 to 3 mm in the maximum cross-sectional dimension.

[0023] In one example, the energy of the first sub-pulse group is in the range of 1 to 65 J. In another example, the energy of the first sub-pulse group is in the range of 6.5 to 65 J.

[0024] In one example, the energy of the second sub-pulse group is in the range of 1 to 6.5 J.

[0025] In one example, the target calculus has an ablation threshold, and the energy of the first sub-pulse group does not exceed the ablation threshold. In another example, the target calculus has an ablation threshold, and the energy of the first sub-pulse group is less than 1.5 times the ablation threshold.

[0026] In one example, the average power of the first sub-pulse group is in the range of 50 to 200 watts (W).

[0027] In one example, the first sub-pulse group includes at least two sub-pulses that are temporally separated by a sub-pulse interval. In another example, the sub-pulse interval is a duration that prevents fluid penetration of the region of the target stone exposed to the pulsed laser energy.

[0028] In one example, the first sub-pulse group includes 1 to 100 sub-pulses.

[0029] In one example, the peak power of the second sub-pulse group is in the range of 500 to 20,000 W. In another example, the peak power of the second sub-pulse group is in the range of 500 to 1500 W.

[0030] In one example, the laser is a thulium fiber laser or a solid-state laser.

[0031] These exemplary aspects and embodiments, as well as still other aspects, embodiments, and advantages, are discussed in detail below. Further, the foregoing information and the following detailed description are merely exemplary examples of various aspects and embodiments, and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed aspects and embodiments. It should be understood that the embodiments disclosed herein may be combined with other embodiments, and references to "one embodiment", "an example", "some embodiments", "some examples", "an alternative embodiment", "various embodiments", "one embodiment", "at least one embodiment", "this embodiment and other embodiments", "a particular embodiment", etc., are not necessarily mutually exclusive, and are intended to indicate that the particular features, structures, or characteristics described may be included in at least one embodiment. The appearance of such terms in this specification does not necessarily refer to all the same embodiments.

[0032] Various aspects of at least one embodiment are discussed below with reference to the accompanying drawings, which are not intended to be drawn to scale. The drawings are included to illustrate and further understand the various aspects and embodiments, are incorporated into and form part of this specification, but are not intended to be limitations on any particular embodiment. The drawings, together with the rest of this specification, are helpful in illustrating the principles and operation of the aspects and embodiments described and claimed herein. In the drawings, each component that is identical or substantially identical shown in various drawings is represented by similar numbers. For clarity, not all components may be labeled in all drawings. The drawings are as follows: [Brief explanation of the drawing]

[0033] [Figure 1A] This chart shows an example of a pulse sequence optimized for pulverization treatment according to one or more aspects of the present invention. [Figure 1B] This chart shows another example of a pulse sequence optimized for pulverization treatment according to one or more aspects of the present invention. [Figure 1C] This chart shows another example of a pulse sequence optimized for pulverization treatment according to one or more aspects of the present invention. [Figure 2A] This chart shows an example of a pulse sequence optimized for stone fragmentation treatment according to one or more aspects of the present invention. [Figure 2B] This chart shows another example of a pulse sequence optimized for stone fragmentation treatment according to one or more aspects of the present invention. [Figure 3] This image, captured from a high-speed video of a stone ablation procedure, shows the distribution and amount of ablation product between the stone and the distal end of the fiber according to an embodiment of the present invention. [Figure 4] These are three images taken from a high-speed video of a lithotripsy procedure, showing thermal radiation at the distal end of the fiber according to an embodiment of the present invention. [Figure 5]This chart shows an example of transmission vibration over time according to an aspect of the present invention. [Figure 6] This chart shows an example of the number of transmitted vibrations over time according to an aspect of the present invention. [Figure 7A] This chart shows an example of a pulse optimized to reduce backward movement, based on prior art. [Figure 7B] This chart shows an example of a pulse sequence optimized to reduce backward movement according to one or more aspects of the present invention. [Figure 7C] This chart shows another example of a pulse sequence optimized to reduce backward movement, according to one or more aspects of the present invention. [Figure 8] This chart shows an example of a pulse profile according to an aspect of the present invention. [Figure 9] This chart shows an example of a pulse configuration according to an aspect of the present invention. [Figure 10] This is a block diagram of a laser system for treating kidney stones according to one or more aspects of the present invention. [Modes for carrying out the invention]

[0034] According to one or more embodiments, specific systems and methods for modulating laser emission for the specific purpose of treating gallstones are discussed below. As used herein, the term “gallstone” refers to a calculus (stone) located in an anatomical location such as the ureter, kidney, or bladder. Gallstones include all types of stones in the body of a human or animal. One or more embodiments of this disclosure may be used with a diode-excited thulium (Tm) and holmium (Ho)-doped crystal or fiber laser having an output wavelength in the range of 1.85 μm to 2.2 μm. In some embodiments, a Tm fiber laser or a Tm:YAG laser may be employed. In some embodiments, a solid-state laser such as Tm:YAG or Ho:YAG may be used. According to various embodiments, a thulium fiber laser, a thulium solid-state laser, or a holmium solid-state laser may be used in the systems and methods described herein.

[0035] Maximizing the efficiency of the stone powdering process (powdering operation mode) The primary objective of pulverization is to generate the smallest possible stone fragments in the shortest possible time. The clinical goal of pulverization is to break the stone into particles having a size of less than 1 mm (preferably less than 0.25 mm, which is considered “fine pulverization”) to ensure the natural expulsion of all fragments within a few weeks post-operatively and prevent new stone formation. According to the pulverization modes described herein, according to at least one embodiment, the size of the stone fragments after exposure to a pulsed laser beam is less than 1 mm in maximum cross-sectional dimension (if the fragment is circular, this would be the diameter), and in some embodiments, less than 0.25 mm in maximum cross-sectional dimension. Conventional laser pulverization procedures utilize regular pulses generated by a laser that is not configured with any kind of special modulation. For example, the regular pulses generated by thulium fiber lasers, which are widely used in clinical practice, have a rectangular or flat-top pulse shape. Typically, these pulses have spurious modulation associated with relaxation oscillations, which appear as spikes with pulse lengths of 0.01 to 5 microseconds (μs). However, the typical energy of these spikes is lower than the threshold for lithotripsy, and the effect of these spikes is negligible. The pulse structure and pulse shape disclosed and described herein are defined regardless of the presence of such spikes.

[0036] At a fixed average power, the use of conventional high pulse energy / low repetition rate operating modes results in relatively large fragments that must be further destroyed. Alternatively, the use of conventional low pulse energy / high repetition rate operating modes produces smaller fragments, but lacks stone ablation efficiency and therefore leads to increased treatment time. Both of these results are suboptimal.

[0037] According to a particular embodiment, two pulverization mechanisms are proposed.

[0038] (1) Adiabatic evaporation of water in the gaps between microcrystals that form the stone, as well as in clusters of microcrystals, and in pores and defects in other stones that are filled with water. The vapor pressure resulting from the evaporation of water initiates stone fragmentation into microcrystals having a size in the range of 0.01 to 50 μm, or into clusters having a size in the range of 10 to 1000 μm. To maximize the efficiency of this mechanism, in some embodiments the pulse width is shorter than the thermal relaxation time of the intercrystal or intercluster space filled with (thermally confined) water, and preferably shorter than the relaxation time of the (acoustically confined) vapor pressure. According to at least one embodiment, the laser pulse energy and fluence are higher than the water evaporation energy threshold.

[0039] (2) Microchipping (exfoliation) of small fragments from the bottom of the laser crater caused by a thermomechanical pressure gradient perpendicular to the surface at the bottom of the laser crater. The thickness of the microchip is approximately equal to the penetration depth of the laser light into the stone, defined by the absorption coefficient of water. The pulse width (pulse duration) should be shorter than the thermal relaxation time of the stone layer having a thickness corresponding to the penetration depth. Another mechanism of laser-induced exfoliation of small fragments from the bottom of the laser crater may be due to the formation of a dry layer of stone after the laser pulse, the penetration of energy of subsequent pulses through this layer, and the ablation of the wet stone layer beneath the dry layer.

[0040] The laser systems and methods disclosed herein are based on the applicant's finding that laser pulse structure modulation provides a substantial improvement in the rate of pulverization and a reduction in average fragment size. This finding was obtained by comparing various pulse structures and shapes generated by the laser with modulated pulse structures using preclinical and clinical settings and standard experimental methodologies. The pulse structure and shape, energy, power and pulse interval range, pulse length and other characteristics were defined based on a substantial improvement (greater than 25%) compared to existing (conventional) conventional pulse treatments. According to at least one embodiment, the pulverization treatment is performed using pulses with relatively low energy or pulses structured as a sequence of optimal subpulses (micropulses). In some embodiments, the subpulses or micropulses are implemented with short intervals between them to prevent stone cooling by water penetration between subpulses. As used herein, the terms “subpulse” or “micropulse” refer to short pulses, many of which together form a resulting pulse. In one embodiment, the sequence of low-energy subpulses is combined into groups of 2 to 1000 pulses; in another embodiment, into groups of 2 to 100 pulses; and in yet another embodiment, into groups of 2 to 10 pulses. According to at least one embodiment, the size of the gallstone is less than 0.25 mm in diameter.

[0041] Figure 1A shows one non-limiting example of two sub-pulse groups used in a pulse sequence for pulverization. The term “sub-pulse group” refers to several sub-pulses that are temporally separated (from each other) by the sub-pulse interval when transmitted. The sub-pulse groups are temporally separated by the pulse repetition interval. According to at least one embodiment, the sub-pulse group is initiated by one or more sub-pulses of lower peak power for the purpose of minimizing the back-movement effect, i.e., when the stone fragments are moving away from the energy source. In some embodiments, the peak power may be increased after the first 1-3 pulses. The presence of multiple short micropulses of low energy generates sufficiently small fragments, while the high cumulative energy created by the pulse sequence delivered at relatively short time intervals ensures high ablation efficiency. After ablation by each micropulse, the bottom of the laser crater is covered with a thin layer of dry stone with evaporated water. This layer can be removed by the next pulse as micro-chipping or delamination of the stone at the bottom of the laser crater, due to the ablation of the wet stone beneath the dry layer. For high ablation efficiency, it is important to keep the interval between pulses shorter than the penetration time of water in the dry layer that occurs between micropulses and cools the stone. According to some embodiments, the subpulse interval is in the range of 0 to 10 ms, in some embodiments it is in the range of 0.01 to 5 ms, in some embodiments it is in the range of 0.01 to 1 ms, in some embodiments it is in the range of 0.01 to 0.2 ms, and in some embodiments it is in the range of 0.01 to 1 ms. According to a particular embodiment, one or more of the subpulse intervals within a subpulse group can vary. For example, in Figure 1A, the first subpulse group includes four subpulses, and the subpulse interval between the first subpulse and the second subpulse is 0 (meaning that the first subpulse and the second subpulse are linked, as shown in Figure 1A), and this first subpulse interval is a different value from the duration of the other subpulse intervals within the subpulse group.

[0042] Some embodiments may include variations of the base sequence in Figure 1A. For example, the first few pulses in the sequence may have gradually increasing amplitude (peak power) to further minimize backward movement and shift the residual fragment size distribution toward smaller particles. One non-limiting example of such a group of pulses composed of such sequences is shown in Figure 1B, which is another example of a pulse sequence that may be used for pulverization treatment.

[0043] An additional example of a pulse sequence that may be used for pulverization is shown in Figure 1C. According to at least one embodiment, at least one subpulse in the subpulse group has a pulse shape such that the power of at least one subpulse increases monotonically from the beginning to the end of the subpulse. The second, third, and fourth pulses in the subpulse group in Figure 1C are non-limiting examples of such power profiles having a monotonically increasing function. This configuration and other examples are discussed in further detail below.

[0044] Returning to Figure 1C as an example, each subpulse can be optimized to have a pulse shape that maximizes the effect of stone ablation accompanied by powder formation. In experimental work using high-speed imaging, the applicant discovered that the attenuation of the laser beam increases during the laser pulse, and this effect increases with the peak power of the rectangular pulse. There are two mechanisms that can explain this phenomenon.

[0045] The first mechanism is due to the increased scattering and absorption of the laser beam relative to the flow of ablation products (a shielding effect on the laser crater) with increasing laser power. Figures 3A and 3B show two video frames of ablation craters and the flow of ablation products (i.e., particle-powder flow) of COM ore exposed to rectangular laser pulses generated by a thulium fiber laser with a wavelength of 1.94 μm, energy of 0.5 J, and peak power of 250 W (Figure 3A) and 2000 W (Figure 3B), with particular attention paid to the end of the laser pulse. From these figures, it can be seen that the angle of the ablation particle flow is greater at the lower peak power (Figure 3A) than at the higher peak power (Figure 3B), but the particle quantity and density, as well as beam scattering and absorption, are lower at 250 W (Figure 3A) compared to 2000 W (Figure 3B).

[0046] The second mechanism discovered is shown in Figure 4, which shows three frames ((i), (ii), and (iii)) of video captured by a high-speed camera, which were used to deliver laser energy from the same fiber (i.e., a thulium fiber laser directed to a COM stone) as in Figures 3A and 3B, but with peak powers of 500 W (i), 1000 W (ii), and 2000 W (iii) at the end of rectangular pulses and an energy of 2 J, including video frames of the ablation crater and fiber tip state. The figure shows that the fiber tip is emitting visible light, which is thermal radiation from the fiber tip heated to a high temperature due to the initial ablation of the ablation product contaminating the distal end of the fiber tip with laser energy. The intensity of such thermal radiation in the visible spectrum increases with tip temperature. The image shown in Figure 4 shows that at a peak power of 500W (i), there is no thermal radiation from the fiber tip; at 1000W (ii), there is low thermal radiation; and at 2000W (iii), there is very strong thermal radiation. The tip temperature at the end of the pulse is below 400°C at 500W, 600-900°C at 1000W, and above 1300°C at 2000W. It is known that heating a quartz fiber to temperatures above 800°C causes a rapid increase in its absorption in the quartz material. This, in turn, increases the attenuation of the laser energy delivered to the stone for ablation, reducing the ablation efficiency. Normally, increasing the peak power or rectangular pulse with a given energy leads to an increase in ablation efficiency, but the additional effects of the two discovered mechanisms can negate or even reverse this effect. Comparing Figures 4(i), (ii), and (iii), it is clear that for the same laser energy of 2J, the crater size at the higher peak power (iii) is smaller than that at the lower peak power (i).There should be an optimal peak power that provides maximum ablation efficiency due to a combination of such mechanisms for any given conditions (local composition and structure of the stone, laser pulse energy, fiber diameter, distance between the fiber tip and the stone, etc.). Since this optimal peak power depends on factors that may change during stone treatment, according to at least one embodiment, a pulse shape having power that varies within a certain range of pulses ensures that this range contains the optimal peak power for various locations on the stone surface, changing gaps, and other variables during treatment.

[0047] According to at least one embodiment, at least one subpulse in a subpulse group has a pulse shape such that the power of at least one subpulse increases from the beginning to the end of the subpulse. According to various embodiments, this increase can be monotonic or non-monotonical. The increase can follow one or more functions, e.g., a step function, linear, polynomial, or exponential function. The second, third, and fourth pulses of the subpulse group in Figure 1C are non-limiting examples of such power profiles having a monotonically increasing function. In some embodiments, the energy of such subpulses can be in the range of 0.2 to 1 J. In some embodiments, the interval between such subpulses is in the range of 0.01 to 5 ms for the purpose of preventing water penetration into the laser crater between subpulses.

[0048] According to at least one embodiment, the optimal laser parameters for a pulverization operation mode using pulse modulation as described above are as follows: • Energy of each subpulse: 0.001 to 1 J, in some embodiments 0.01 to 1 J, in further embodiments 0.2 to 1 J, and in some embodiments the subpulse energy may vary within a subpulse group, for example, the first subpulse may have lower energy than the second subpulse in the subpulse group. The total energy of the pulse (energy of the sub-pulse group) is 0.2 to 5 J, preferably 0.5 to 2 J. • Pulse width (subpulse duration): 0.001 to 5 ms, preferably 0.1 to 1 ms, and in some embodiments, the subpulse duration may vary within a subpulse group, for example, the first subpulse may have a longer duration than the second subpulse within the subpulse group. The interval between micropulses (subpulse interval) is 0 to 10 ms, preferably 0.01 to 5 ms, and more preferably 0.01 to 1 ms. The average power depends on the anatomical location and the perfusion and suction speed, and is typically in the range of 2-120W, preferably 5-15W, in the ureter, 2-40W in the kidney, and 5-40W and 5-60W in the bladder. • Pulse repetition interval: 1 to 1000 ms. • Pulse repetition rate (within the sub-pulse group): in the range of 0.5 to 500 Hz. • (Peak power of subpulses within a subpulse group): In the range of 250 to 20,000 W, preferably in the range of 500 to 5,000 W, and in some embodiments, the peak power may vary within a subpulse group, for example, the first subpulse may have a lower or higher peak power than the second subpulse within the subpulse group.

[0049] To maximize the efficiency of the stone fragmentation treatment (fragmentation operation mode) The primary objective of stone fragmentation treatment is to break the stone into fragments small enough to be extracted by a basket or other tool, for example, by suction (usually for fragments of about 3 mm in size or less), especially when rigid instruments are used. Based on theoretical modeling, experimental work and clinical trials performed by the applicant, a novel mechanism of stone fragmentation is proposed and demonstrated and disclosed herein. For this purpose, according to at least one embodiment, the optimal scenario of treatment is to (1) first create a temperature gradient in the stone to generate mechanical stress in the stone structure by the slow release of residual laser energy converted into heating energy, and (2) then apply strong thermomechanical shocks to the stressed stone structure through shorter, higher energy pulses to generate cracks (typically one-dimensional linear defects (dislocations), two-dimensional surface defects (particles, microcrystalline clusters or crystalline domains, boundaries and free surfaces), and three-dimensional volume defects (pores), or along other surfaces separating regions of the stone having different structures, ultimately leading to the fracture of the stone. In certain embodiments, this is two parts: (mark This can be achieved using a laser pulse consisting of a first (initial) subpulse group to generate mechanical stress (within the target calculus) and a second (subsequent) subpulse group to generate thermomechanical shock, i.e., cracks in the mechanically stressed stone (target calculus). As used herein, the term “mechanical stress” refers to structural stress within the calculus resulting from pressure fluctuations or thermal gradients within the calculus, such stress can lead to fragmentation of the calculus itself. As used herein, the term “thermomechanical shock” refers to calculus fragmentation caused by thermal strain energy and stress, which occurs much faster during interaction with the first subpulse group (as will be described in more detail below).

[0050] According to one embodiment, the technique first injects sufficient laser energy into the stone without causing substantial ablation, and then delivers the aforementioned thermomechanical shock by following up with strong pulses. Note that in the fragmentation mode, the backward movement effect is less significant than in the pulverization mode, as typically only sufficiently large stones (about 8 mm or larger) are targeted for fragmentation. According to the fragmentation modes described herein, according to at least one embodiment, the size of the stone fragments after exposure to pulsed laser energy is at least 1 mm in maximum cross-sectional dimension (which would be the diameter in the case of circular fragments), and in some embodiments, the size of the stone fragments after exposure to pulsed laser energy is in the range of 1 to 5 mm in maximum cross-sectional dimension, and in preferred embodiments, it is in the range of 1 to 3 mm in maximum cross-sectional dimension.

[0051] In one embodiment, the desired effect can be achieved by applying a first subpulse group (1-100), where each subpulse of the first group has relatively low energy, and the subpulse interval (interval between subpulses) is short enough to prevent water (fluid) from penetrating the treatment area of ​​the stone during the subpulse interval, which functions to cool the stone structure. Then, an energy pulse is applied with a higher peak power (this may be referred to herein as the second subpulse group for simplicity). Thus, in some embodiments, the emitted pulsed laser energy includes two subpulse groups separated in time by a subpulse group interval. In certain embodiments, the first subpulse group has a subpulse group interval with a duration that prevents fluid penetration into the area of ​​the target stone exposed to the pulsed laser energy. In some embodiments, each group of subpulses includes at least two subpulses separated in time by a subpulse interval in the range of 0-1 ms. A subpulse interval with a value of 0 indicates that two subpulses are linked (see, for example, the first subpulse group in Figure 2B) and, in some cases, can be considered as a single subpulse. A second subpulse group may also have a subpulse interval of zero, indicating that the subpulses are linked (see, for example, the second subpulse group in Figure 2B). According to some embodiments, the first and second subpulse groups can be grouped together into a pulse group, which can be emitted continuously, and the pulse group is separated by a pulse repetition interval, as shown in Figure 2A.

[0052] A non-limiting example of a fragmentation mode for treating gallstones is shown in Figure 2A. During the first subpulse group phase of gallstone treatment with this therapy, residual heating energy from each subpulse propagates into the gallstone structure, creating a non-uniform temperature distribution and mechanical stress around the treatment area where the laser pulses propagate and are absorbed by the gallstone. According to at least one embodiment, the first subpulse group has a total energy (i.e., the combined energy of all subpulses included in the first subpulse group), a total pulse length (i.e., the combined pulse length (duration) of all subpulses in the first subpulse group), and an average power (i.e., the average power of the subpulses included in the first subpulse group) sufficient to generate mechanical stress in the target gallstone. If the energy of each individual subpulse is below the ablation threshold, only the phenomenon of mechanical stress occurs. If the energy of each individual subpulse is above the ablation threshold, pulverization occurs in addition to gallstone ablation. According to at least one embodiment, the second subpulse group has sufficient total energy (i.e., the combined energy of all subpulses included in the second subpulse group), total pulse length (i.e., the combined pulse length (duration) of all subpulses in the second subpulse group) and average power (i.e., the average power of the subpulses included in the second subpulse group) to generate a thermomechanical shock to the target stone. The latter effect will be described in more detail below. This combined effect enables the ability to fragment the target stone into fragments larger than 1 mm.

[0053] According to alternative embodiments, the subpulse group can be replaced by a single pulse with sufficiently low peak power and long duration, having power below or slightly above the ablation threshold (<1.5 times). In some embodiments, the target stone has an ablation threshold, and the energy of the first subpulse group does not exceed the ablation threshold. In another embodiment, the energy of the first subpulse group does not exceed the ablation threshold multiplied by a factor of 1.5.

[0054] One non-limiting example of another fragmentation mode for treating kidney stones is shown in Figure 2B. Preheating via a first sub-pulse group with lower power results in increased mechanical stress around the laser-irradiated stone area, leading to an increase in the absorption coefficient of the stone matrix of the stone or mineral or organic components due to heating above 100–250°C. A second sub-pulse group with higher power is absorbed more effectively by the stone material due to better absorption compared to the first sub-pulse group, generating more efficient thermomechanical damage and stress. The higher peak power of the second sub-pulse group, combined with the initial mechanical stress in the stone around the laser-irradiated area, results in an increased likelihood of the stone breaking into larger pieces.

[0055] According to both approaches described above, in certain embodiments, the two groups of subpulse shape structures described may consist of high energy (up to 70 J) and low repetition rates (0.5–5 Hz). The applicant has found that such high-energy pulses cause less damage when they accidentally hit soft tissue compared to "normal" low-energy pulses having the same average power and higher repetition rates as the two disclosed subpulse groups. This makes the disclosed stone treatment safer compared to conventional laser operating parameters used for stone fragmentation.

[0056] According to at least one embodiment, the optimal laser parameters for a fragmentation operation mode using pulse shape modulation as described above are as follows: The total pulse energy, including the first and second subpulse groups, is 2 to 70 J, preferably 2 to 4 J for ureteral stones and 7 to 60 J for kidney stones and bladder stones. The energy of the first sub-pulse group is 1 to 65 J, and in some embodiments, 6.5 to 65 J, and in some embodiments, 1 to 3 J for ureteral stones and 7 to 60 J for kidney stones and bladder stones. The energy of the second sub-pulse group is 1 to 10 J, and in some embodiments, 1 to 6.5 J, and in some embodiments, 1 to 3 J for ureteral stones and 3 to 10 J for kidney stones and bladder stones. The average power of the first sub-pulse group is 50-200W. The peak power of the pulses in the second sub-pulse group is 500 to 20,000 W, preferably 500 to 1,500 W. The repetition rates of the two subpulse groups are 0.5 to 10 Hz, preferably 0.5 to 5 Hz for ureteral stones and 0.5 to 2 Hz for kidney stones or bladder stones.

[0057] vibration It is conventionally known that during laser pulses in water, water evaporation occurs, forming vapor channels (Moses channels) between the distal end of the fiber and the stone surface. Experiments conducted by the applicant revealed that the channel initially expands in size, creating a vapor channel from the distal end of the fiber to the stone surface, and then collapses. After collapse, another channel is formed during the laser pulse, and this process is repeated throughout the duration of the laser pulse. This phenomenon, recognized by the applicant, is called the oscillation of the evaporation (Moses) channel. This channel oscillation occurs because the laser energy input to create the channel stops when the channel is formed, and this energy is stored in the surrounding water as increased potential energy. This potential energy relaxes, causing the channel to collapse. The coupling of laser energy to the collapsing water restarts the evaporation process, leading to the formation of the next channel. This process is repeated throughout the duration of the laser pulse. Experiments conducted by the applicant showed that, during the laser pulse, the transmission of laser power to the stone also oscillates during the laser pulse due to the oscillation of the vapor (Moses) channel. Figure 5 shows the transmission of laser power through an oscillating vapor channel (black curve) when the fiber-to-stone distance is 0.8 mm and the laser power (labeled in the figure) is 500 W for a pulse duration of 1 ms (using a TFL laser, 500 W peak power, and 1 ms pulse duration). As shown in Figure 6, the number of transmitted oscillations increases linearly with pulse duration at a rate dependent on the fiber-to-stone distance.

[0058] Reduced backward movement (operating mode) The water flow during channel formation and expansion, the vapor pressure within the channel, and the water flow during and after channel collapse are all forces acting on the stone at different times. The final result is the vibrational motion of the stone, which occurs in sync with the channel vibration. The applicant refers to this as the “capture” effect. Experiments conducted by the applicant demonstrated that the amplitude of the stone vibration during the capture effect is much smaller than 1 mm for a stone size of approximately 5 mm. Smaller / larger amplitude vibrations are expected for larger / smaller stones, respectively. The non-vibrational motion of the stone after the laser pulse depends on the characteristics and timing of the final channel collapse. The final channel collapse generates water flow, which is the main cause of undesirable backward movement of the stone. The direction of the water flow depends on the conditions of the final channel, i.e., the channel shape, the velocity at its boundary, and the pressure difference. For example, symmetrical channel collapse does not generate any net fluid momentum that can be transmitted to the stone. Conversely, a well-formed channel can collapse, providing negative / positive stone motion toward / away from the fiber, respectively. The final channel state can be controlled by the laser power and pulse profile. The use of a combination of two sub-pulses to reduce backshift is known in the art, an example of which is shown in Figure 7A, which is from PCT application PCT / US2019 / 042491, published as International Publication 2020 / 033121, owned by the applicant, and incorporated herein by reference in its entirety. A first sub-pulse or portion is used to initiate channel formation between the fiber and the stone, ablation of the stone, and preheating of the stone around the ablation crater, depending on the distance between the fiber and the stone. Recent experiments by the applicant have demonstrated that backshift can be further reduced if the duration of the first sub-pulse is reduced to a fraction of a single channel period. The backshift effect of such pulse generation will be reduced because a more symmetrical channel and channel collapse will occur and less momentum will be transferred to the fluid. In Figure 7A, T1 is the duration of the first sub-pulse or portion, and T2 is the duration of the second sub-pulse or portion.In addition, the energy or power profile of the first subpulse or portion is at level P. min It is constant, or P min From P max The function can take the form of a linear function, exponential function, or polynomial function that increases up to P, where P max is the peak power of the second subpulse or portion. Recent experiments by the applicant have demonstrated that when the power of the first subpulse is low and its duration is synchronized with the frequency of the channel or bubble, a further reduction in backshift occurs.

[0059] Recent research conducted by the applicant has demonstrated the importance of both the leading and trailing edges of the pulse. In particular, the collapse rate of the final Moses channel can be reduced at lower power settings, delaying the final collapse and decreasing the flow velocity of the collapsing water. This is achieved by introducing an additional post-subpulse at the reduced power level, thereby creating a “triple” pulse, i.e., three subpulses. In some embodiments, the controller is configured to adjust the laser power profile so that each emitted pulse energy contains three subpulses. One non-limiting example of such a “triple” pulse is shown in Figure 7B. As shown in Figure 7B, the first subpulse (energy) may increase according to a linear, polynomial, or exponential function, and the third subpulse may decrease according to a linear, polynomial, or exponential function. In addition, the third subpulse (energy, power) is at level P minThis can be kept constant. Furthermore, some embodiments of the "triple" pulse (energy, power) may involve the use of subpulses with opposite gradients, a non-limiting example of which is shown in Figure 7C. For example, in some embodiments, the energy gradients of the first and third subpulses are reciprocals of each other. In yet other embodiments, the later subpulse format may include a sequence of subpulses that are chirpened (reducing pulse duration and pulse power) to match the decreasing Moses channel diameter and their duration (proportional to the channel diameter under a given ambient pressure).

[0060] According to at least one embodiment, the following laser parameters are optimal for the preceding first and following third subpulses in order to reduce backward movement and further ensure the effectiveness of the pulse for the intended purpose (e.g., pulverization, fragmentation): • Peak power is in the range of 50 to 200 W, preferably in the range of 100 to 130 W. The pulse energy is in the range of 0.005 to 1 J, preferably in the range of 0.01 to 0.3 J. • The duration of the first subpulse is in the range of 100 microseconds to 1 ms. According to some embodiments, the following laser parameters may be used in a reduced backward movement mode: • The second subpulse has higher energy than the first and third subpulses. • The second sub-pulse energy is in the range of 0.01 to 10 J and 0.1 to 3 J. The second subpulse peak power is in the range of 400 to 4000 W, preferably in the range of 400 to 1500 W. • The sub-pulse interval (duration between sub-pulses) is in the range of 0 to 0.5 ms. • The sub-pulse interval is in the range of 0 to 300 μs. • The subpulse duration is in the range of 0.1 to 1 ms.

[0061] An additional embodiment, as shown in Figure 8, involves the concept that the laser power is increased at the end of the pulse, which results in a faster channel recovery. Thus, more energy is transferred to the stone for ablation per pulse.

[0062] For stones that have moved away from the fiber (distance > 2 mm), the pulse profile shown in Figure 8 can be applied to pull the stones back towards the fiber (negative backward movement). The applicant refers to this process as stone "retraction." This occurs because the final Moses channel collapses, similar to how water flows towards the fiber.

[0063] According to these embodiments, the following laser parameters may be used in the enhanced ablation efficiency / retraction mode: • The first subpulse has lower energy than the subsequent subpulse. • The second sub-pulse energy is in the range of 0.01–10 J, and the intermediate power level for channel evaporation is in the range of 0.1–3 J. The third subpulse is at its highest power level to generate higher pressure at the distal end of the channel (near the rock) due to greater asymmetrical collapse (collapse towards the fiber) at the distal end than at the proximal end.

[0064] Stones smaller than 5 mm can be captured and vibrated during a laser pulse. The amplitude of the stone vibration can be in the range of 0.1 to 3 mm, and the frequency of the Moses channel vibration can be in the range of 0.5 to 10 kHz, depending on the average fiber-stone distance. The above embodiment is a method for reducing or maintaining the average distance of the stone relative to the fiber and increasing the ablation efficiency accordingly. An additional method for both increasing the ablation efficiency and reducing backshifting is to enable laser pulse power modulation synchronized with the Moses channel vibration (Figure 8), and also to reduce the amplitude of the stone vibration to less than 1 mm, preferably less than 0.5 mm. This will increase the ablation efficiency.

[0065] The applicant observed that there are three important phases in a laser pulse: Phase 1, duration T1, is the optimal power and duration for initiating channel formation, influencing the shape and dynamics of the channel near the fiber. Phase 2, duration T2, is the optimal power and duration for rock ablation (through a fully developed channel). Phase 3, duration T3, is the optimal power and pulse duration for final channel collapse at the end of the laser pulse. Thus, the power in the laser pulse can be modulated and synchronized with channel oscillations to increase ablation efficiency while simultaneously reducing backmovement. A non-limiting example of such a pulse configuration is shown in Figure 9. Period T1 is set to a power such that it affects the state of the Moses channel at the fiber end, T2 is set to a high power for the best rock ablation rate, and T3 is set to a power level such that symmetric channel conditions are obtained from the rock end to the fiber end for reduced backmovement.

[0066] According to these embodiments, the following laser parameters may be used in this operating mode: • The duration T1 is in the range of 0.050 to 2ms at a power range of 50 to 250W, preferably 100 to 130W. • Duration T2 is in the range of 0.050 to 2ms at power levels ranging from 50 to 4000W. • Duration T3 is in the range of 0.050 to 2 ms for power levels in the range of 50 to 1000 W, and pulse energy is in the range of 0.005 to 1 J. • Duration T4 is in the range of 1-6ms at power levels ranging from 50 to 4000W.

[0067] Laser system Figure 10 is a block diagram showing one non-exclusive example of a laser system configured to generate the laser pulse operating modes described above. It should be understood that other configurations may be used to implement the aforementioned pulse modes.

[0068] The laser system 100 comprises a power supply 103, a laser driver 125 which may include an optional energy storage device 120, a pump 115, a laser module 130, and a controller 150, also referred to herein as a control module. Laser energy from the laser module 130 is directed to the target stone 160. The laser system 100 may also include a beam delivery system or module 145 and an optical coupler 140.

[0069] Pump 115 is configured with one or more diode lasers that energize the laser 130. Power supply 103 powers the system, and an optional energy storage device 125 (e.g., an electrical capacitor and / or inductor) can be configured to store a sufficient amount of energy to form laser pulses. The laser driver 125 of pump 115 forms electrical pulses of specified characteristics in response to control signals from the control module 150. The electrical pulses are received by one or more diodes in pump 115 that form optical pulses necessary to pump the laser medium in the laser module 130. The output of the laser module 130 is coupled to a beam delivery system 145, and in some cases, this coupling occurs via an optical coupler 140.

[0070] One or more components of the laser system 100 are controlled by a controller 150, which is programmed with control signals used to control the laser driver 125, the power supply 103, and / or the laser module 130. For example, control signals from the controller 150 can be used to directly modulate the pump current of the driver 125, which is used to pump the diode 115 to output a desired pulse energy, power, and temporal structure, as will be understood by those skilled in the art. In some embodiments, the diode current can be modulated using a single charge-discharge cycle of the energy storage device 120.

[0071] The embodiments disclosed herein in accordance with the present invention are not limited in their application to the configuration details and arrangement of components described below or shown in the accompanying drawings. These embodiments can incorporate other embodiments and can be implemented or performed in a variety of ways. Examples of specific implementations are provided herein for illustrative purposes only and are not intended to limit them. In particular, the operations, components, elements, and features considered in relation to any one or more embodiments are not intended to be excluded from similar roles in any other embodiments.

[0072] Furthermore, the expressions and terms used herein are for illustrative purposes only and should not be considered limiting. Any singular reference to an example, embodiment, component, element, or act of a system or method herein may include plural embodiments, and any plural reference to any embodiment, component, element, or act herein may include singular embodiments. References in the singular or plural form are not intended to limit the systems or methods, their components, acts, or elements of the disclosure. The use of “includes,” “equips,” “has,” “contains,” “accompanies,” and variations thereof herein means that the items listed thereafter and their equivalents, as well as additional items, are included. References to “or” may be interpreted as comprehensive, such that any term used with “or” may refer to one, two or more, or all of the terms listed. Furthermore, in the event of any inconsistency in the use of terminology between this document and any document incorporated herein by reference, the use of terminology in the incorporated reference should be considered supplementary to the use herein. In the event of irreconcilable inconsistencies, the use of terminology herein shall prevail. Furthermore, titles or subtitles may be used herein for the convenience of the reader and shall not affect the scope of the invention.

[0073] While several aspects of at least one example have been described in this manner, it should be understood that various changes, modifications, and improvements will be readily conceivable to those skilled in the art. For example, the examples disclosed herein may be used in other contexts. Such changes, modifications, and improvements are intended to be part of this disclosure and within the scope of the examples considered herein. Thus, the description and drawings herein are merely examples.

Claims

1. A laser system for treating kidney stones, A laser configured to emit pulsed laser energy having a wavelength in the range of 1.85 to 2.2 μm, A controller configured to control the laser such that the pulsed laser energy is emitted as a sequence of subpulse groups separated in time by a pulse repetition interval, wherein each subpulse group includes at least two subpulses separated in time by a subpulse interval in the range of 0 to 10 ms. Each subpulse in the subpulse group has a pulse duration in the range of 0.001 to 5 ms. Each subpulse in the subpulse group has an energy in the range of 0.001 to 1 J. A laser system in which the pulse repetition interval is in the range of 1 to 1000 ms.

2. The laser system according to claim 1, wherein the subpulse group includes 2 to 1,000 subpulses.

3. The laser system according to claim 2, wherein the subpulse group includes 2 to 100 subpulses.

4. The laser system according to claim 3, wherein the subpulse group includes 2 to 10 subpulses.

5. The laser system according to claim 1, wherein the total energy of the subpulse group is in the range of 0.2 to 5 J.

6. The laser system according to claim 5, wherein the total energy of the subpulse group is in the range of 0.5 to 2 J.

7. The laser system according to claim 1, wherein the energy of each subpulse is in the range of 0.01 to 1 J.

8. The laser system according to claim 7, wherein the energy of each subpulse is in the range of 0.2 to 1 J.

9. The laser system according to claim 1, wherein the subpulse interval is in the range of 0.01 to 5 ms.

10. The laser system according to claim 9, wherein the subpulse interval is in the range of 0.01 to 1 ms.

11. The laser system according to claim 1, wherein the duration of each subpulse is in the range of 0.1 to 1 ms.

12. The laser system according to claim 1, wherein the pulsed laser energy has an average power in the range of 2 to 120 W.

13. The laser system according to claim 12, wherein the average power is in the range of 2 to 40 W.

14. The laser system according to claim 13, wherein the average power is in the range of 5 to 40 W.

15. The laser system according to claim 1, wherein the pulse repetition rate within the subpulse group is in the range of 0.5 to 500 Hz.

16. The laser system according to claim 1, wherein the peak power of the subpulses in the subpulse group is in the range of 250 to 20,000 W.

17. The laser system according to claim 16, wherein the peak power of the subpulses in the subpulse group is in the range of 500 to 5000 W.

18. The laser system according to claim 1, wherein at least one subpulse of the subpulse group has a pulse shape such that the power of the at least one subpulse increases monotonically from the beginning of the subpulse to the end of the subpulse.

19. The laser system according to claim 1, wherein the laser is a thulium fiber laser, a thulium solid-state laser, or a holmium solid-state laser.

20. A method for treating kidney stones, 1. To generate pulsed laser energy having a wavelength in the range of 1.85 to 2.2 μm, The pulse laser energy is emitted as a sequence of subpulse groups separated in time by the pulse repetition interval, Each subpulse group includes at least two subpulses separated in time by a subpulse interval in the range of 0 to 10 ms. Each subpulse in the subpulse group has a pulse duration in the range of 0.001 to 5 ms. Each subpulse in the subpulse group has an energy in the range of 0.001 to 1 J. A method comprising emitting a pulsed laser beam, wherein the pulse repetition interval is in the range of 1 to 1000, and directing the pulsed laser beam to a treatment area for a gallstone.

21. The method according to claim 20, wherein the size of the stone fragments after exposure to the pulsed laser beam is less than 1 mm in maximum cross-sectional dimensions.

22. The method according to claim 20, wherein the subpulse group includes 2 to 1,000 subpulses.

23. The method according to claim 22, wherein the subpulse group includes 2 to 100 subpulses.

24. The method according to claim 23, wherein the subpulse group includes 2 to 10 subpulses.

25. The method according to claim 20, wherein the total energy of the subpulse group is in the range of 0.2 to 5 J.

26. The method according to claim 25, wherein the total energy of the subpulse group is in the range of 0.5 to 2 J.

27. The method according to claim 20, wherein the energy of each subpulse is in the range of 0.01 to 1 J.

28. The method according to claim 27, wherein the energy of each subpulse is in the range of 0.2 to 1 J.

29. The method according to claim 20, wherein the subpulse interval is in the range of 0.01 to 5 ms.

30. The method according to claim 29, wherein the subpulse interval is in the range of 0.01 to 1 ms.

31. The method according to claim 20, wherein the duration of each subpulse is in the range of 0.1 to 1 ms.

32. The method according to claim 20, wherein the pulsed laser energy has an average power in the range of 2 to 120 W.

33. The method according to claim 32, wherein the average power is in the range of 2 to 40 W.

34. The method according to claim 33, wherein the average power is in the range of 5 to 40 W.

35. The method according to claim 20, wherein the pulse repetition rate within the subpulse group is in the range of 0.5 to 500 Hz.

36. The method according to claim 30, wherein the peak power of the subpulses in the subpulse group is in the range of 250 to 20,000 W.

37. The method according to claim 36, wherein the peak power of the subpulses in the subpulse group is in the range of 500 to 5000 W.

38. The method according to claim 20, wherein at least one subpulse of the subpulse group has a pulse shape such that the power of the at least one subpulse increases monotonically from the beginning of the subpulse to the end of the subpulse.

39. The method according to claim 20, further comprising providing a thulium fiber laser, a thulium solid-state laser, or a holmium solid-state laser for generating the pulsed laser energy.

40. A laser system for treating kidney stones, A laser configured to emit pulsed laser energy having a wavelength in the range of 1.85 to 2.2 μm, A controller configured to control the laser such that each pulse of the emitted pulsed laser energy includes two subpulse groups separated in time by a subpulse group interval, Each group of subpulses includes at least two subpulses separated in time by a subpulse interval in the range of 0 to 1 ms. The first sub-pulse group has sufficient total energy, total pulse length, and average power to generate mechanical stress in the target stone. The second sub-pulse group has sufficient total energy, total pulse length, and average power to generate a thermomechanical shock to the target stone. The total energy of the two sub-pulse groups is in the range of 2 to 70 J. A laser system in which the repetition rates of the two subpulse groups are in the range of 0.5 to 10 Hz.

41. The laser system according to claim 40, wherein the size of the fragment of the target calculus after exposure to the pulsed laser energy is at least 1 mm in maximum cross-sectional dimensions.

42. The laser system according to claim 40, wherein the size of the fragment of the target calculus after exposure to the pulsed laser energy is in the range of 1 to 5 mm in maximum cross-sectional dimensions.

43. The laser system according to claim 40, wherein the size of the fragments of the target calculus after exposure to the pulsed laser energy is in the range of 1 to 3 mm in maximum cross-sectional dimensions.

44. The laser system according to claim 40, wherein the energy of the first subpulse group is in the range of 1 to 65 J.

45. The laser system according to claim 44, wherein the energy of the first subpulse group is in the range of 6.5 to 65 J.

46. The laser system according to claim 40, wherein the energy of the second subpulse group is in the range of 1 to 6.5 J.

47. The laser system according to claim 40, wherein the target stone has an ablation threshold, and the energy of the first subpulse group does not exceed the ablation threshold.

48. The laser system according to claim 40, wherein the target stone has an ablation threshold, and the energy of the first subpulse group is less than the ablation threshold multiplied by a coefficient of 1.

5.

49. The laser system according to claim 40, wherein the average power of the first subpulse group is in the range of 50 to 200 W.

50. The laser system according to claim 40, wherein the first subpulse group includes at least two subpulses separated in time by a subpulse interval.

51. The laser system according to claim 50, wherein the sub-pulse interval is a duration that prevents fluid penetration of the region of the target stone exposed to the pulsed laser energy.

52. The laser system according to claim 50, wherein the first subpulse group includes 1 to 100 subpulses.

53. The laser system according to claim 40, wherein the peak power of the second subpulse group is in the range of 500 to 20,000 W.

54. The laser system according to claim 53, wherein the peak power of the second subpulse group is in the range of 500 to 1500 W.

55. The laser system according to claim 40, wherein the laser is a thulium fiber laser or a solid-state laser.

56. A method for treating kidney stones, 1. To generate pulsed laser energy having a wavelength in the range of 1.85 to 2.2 μm, The pulsed laser energy is emitted as two sub-pulse groups separated in time by a sub-pulse interval in the range of 0 to 1 ms, wherein the two sub-pulse groups are The first sub-pulse group has sufficient total energy, total pulse length, and average power to generate mechanical stress in the target stone. The second sub-pulse group has sufficient total energy, total pulse length, and average power to generate a thermomechanical shock to the target stone. The total energy of the two sub-pulse groups is in the range of 2 to 70 J. The two subpulse groups are configured such that their repetition rates are in the range of 0.5 to 10 Hz, and they emit... A method comprising directing a pulsed laser beam towards the target gallstone.

57. The method according to claim 56, wherein the size of the fragment of the target stone after exposure to the pulsed laser energy is at least 1 mm in maximum cross-sectional dimensions.

58. The method according to claim 56, wherein the size of the fragment of the target stone after exposure to the pulsed laser energy is in the range of 1 to 5 mm in maximum cross-sectional dimensions.

59. The method according to claim 56, wherein the size of the fragment of the target stone after exposure to the pulsed laser energy is in the range of 1 to 3 mm in maximum cross-sectional dimensions.

60. The method according to claim 56, wherein the energy of the first subpulse group is in the range of 1 to 65 J.

61. The method according to claim 60, wherein the energy of the first subpulse group is in the range of 6.5 to 65 J.

62. The method according to claim 56, wherein the energy of the second subpulse group is in the range of 1 to 6.5 J.

63. The method according to claim 56, wherein the average power of the first subpulse group is in the range of 50 to 200 watts.

64. The method according to claim 56, wherein the target stone has an ablation threshold, and the energy of the first subpulse group does not exceed the ablation threshold.

65. The method according to claim 56, wherein the target stone has an ablation threshold, and the energy of the first subpulse group is less than the ablation threshold multiplied by a coefficient of 1.

5.

66. The method according to claim 56, wherein the first subpulse group includes at least two subpulses separated in time by a subpulse interval.

67. The method according to claim 66, wherein the sub-pulse interval is a duration that prevents fluid penetration of the region of the target stone exposed to the pulsed laser energy.

68. The method according to claim 56, wherein the first subpulse group includes 1 to 100 subpulses.

69. The method according to claim 56, wherein the peak power of the second subpulse group is in the range of 500 to 20000 W.

70. The method according to claim 69, wherein the peak power of the second subpulse group is in the range of 500 to 1500 W.

71. The method according to claim 56, further comprising providing a thulium fiber laser or a solid-state laser for generating the pulsed laser energy.

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