A new homogenization mode laser ablation system

Abstract

The application discloses a novel homogenization mode laser ablation system and belongs to the technical field of laser medical devices. The application first adopts a diffusing pre-homogenization + square / polygonal integrated rod secondary homogenization mode to convert a Gaussian light beam into a high-uniform flat-top light spot; a multi-polygonal surface type matching coupling is adopted at an incident end of a beam combining fiber to be consistent with an exit surface of the integrated rod, so that the coupling efficiency is remarkably improved. The application solves inherent defects of traditional fiber homogenization, such as hot spot concentration, speckle, large mode noise, easy ablation, low coupling efficiency, and has outstanding advantages of higher uniformity, stronger power tolerance, more regular light spot, lower loss and more stable system compared with fiber homogenization, and greatly improves the safety and efficiency of laser ablation.

Description

Technical Field

[0001] This invention belongs to the field of laser medical equipment technology, specifically relating to a novel uniform light mode laser ablation system. Background Technology

[0002] People with high blood pressure, high cholesterol, heavy smoking, diabetes, or obesity are prone to atherosclerosis. Atherosclerosis can cause narrowing or blockage of blood vessels, leading to poor blood flow and potentially life-threatening situations.

[0003] Interventional arterial therapy has become an effective treatment for patients with atherosclerosis. This therapy involves inserting a catheter into a blood vessel and using techniques such as laser ablation to open narrowed or blocked vessels.

[0004] Laser ablation is a medical technique that uses ultraviolet laser light to ablate atherosclerotic plaques within blood vessels. When the ultraviolet light is absorbed by the atherosclerotic plaque, it breaks down the carbon-hydrogen bonds of the plaque molecules, causing the plaque tissue to heat up and generate microvapor bubbles at the catheter tip. The expansion and contraction of these microvapor bubbles disintegrate the plaque blocking the blood vessel. Simultaneously, debris at the catheter tip is broken down into water, gas, and particles smaller than 10 μm, which are ultimately absorbed by the reticuloendothelial system, thus preventing microvascular blockage.

[0005] Existing laser ablation systems generally use optical fibers for secondary homogenization, which has insurmountable drawbacks: optical fibers transmit in a modal manner, and Gaussian beams tend to retain central hot spots. High spatial coherence easily leads to modal noise, speckle, and lateral energy redistribution, directly causing fiber end-face ablation and catheter damage. Poor homogenization with optical fibers makes it difficult to achieve a truly flat-top beam, resulting in low ablation efficiency and a high risk of thermal damage to the vessel wall.

[0006] Therefore, how to solve the technical problems of uneven spot size, speckle noise, easy device ablation, high coupling loss and poor stability caused by the use of fiber homogenization in existing laser ablation systems has become an important issue that urgently needs to be addressed. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a novel uniform laser ablation system, which aims to solve the technical problems of uneven beam, speckle noise, easy device ablation, high coupling loss, and poor stability caused by the use of fiber homogenization in existing laser ablation systems, so as to achieve high uniformity, low loss, and high stability of laser beam transmission, thereby improving clinical ablation efficiency and surgical safety.

[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a novel laser ablation system with a uniform light mode, comprising a laser, a uniform light module a, a focusing lens group, a uniform light module b, a focusing coupling lens group, and a beam combining fiber optic conduit arranged coaxially along the optical path; the uniform light module a is a diffuser or a holographic uniform light module; the uniform light module b is a solid integrating rod; the incident end of the beam combining fiber optic conduit is designed to match the shape and size of the exit surface of the uniform light module b.

[0009] In this system, beam homogenization module a is a diffuser sheet that achieves initial diffuse homogenization; beam homogenization module b is a square / polygonal solid integrating rod that achieves secondary high-precision homogenization through multiple total internal reflections, converting the beam into a flat-top uniform distribution; the incident end of the beam combining fiber adopts a polygonal surface with the same shape as the exit surface of the integrating rod, achieving surface matching coupling; this system uses the integrating rod as the core homogenization device, which has significant advantages over traditional fiber homogenization: no mode noise, no central hot spot, no speckle interference, higher power tolerance, and better beam uniformity.

[0010] Based on the above scheme, the uniform light module b is a solid ultraviolet fused silica integrating rod with a rectangular or regular hexagonal cross-section.

[0011] Among them, the uniform light module b is a solid ultraviolet fused silica integrating rod, which outputs a flat-top uniform light spot with no central hot spot through total internal reflection mixing on the inner wall.

[0012] Among them, the advantages of integrating rod homogenization compared with fiber homogenization are: (1) no mode interference, no fiber mode noise and speckle; (2) no energy lateral redistribution, avoiding ablation of fiber optic conduit; (3) regular edge of output spot, controllable shape, suitable for clinical ablation area; (4) higher power density tolerance, no risk of fiber core burning, aging, or breakage.

[0013] Based on the above scheme, the incident end face of the bundled fiber optic conduit is polygonal, with a fill factor ≥80% and a coupling loss ≤20%.

[0014] Based on the above scheme, the overall optical path further adopts a coaxial straight cylindrical structure.

[0015] The overall optical path has no reflectors, making assembly and adjustment simple and highly stable.

[0016] Based on the above scheme, the laser is further selected as a semiconductor-pumped ultraviolet laser with an output wavelength of 300nm~400nm ultraviolet laser; the output beam pulse width is 8ns~15ns, the repetition frequency is 25Hz~150Hz, the spot diameter is 4mm~12mm, and the single pulse energy reaches 50mJ~150mJ.

[0017] The laser is used to generate and emit an initial ultraviolet laser beam that conforms to a Gaussian energy distribution. The coupling module includes a homogenizing module a, a focusing lens group, a homogenizing module b, and a focusing coupling lens group connected coaxially in sequence. The end of the coupling module is connected to a bundled fiber optic conduit, which is used to convert the initial Gaussian beam into a highly uniform, low-coherence, hot-spot-free flat-top target beam and efficiently couple it to the conduit target point to act on atherosclerotic plaque tissue.

[0018] The homogenizing module a is a diffuser or a holographic homogenizer, which serves as a pre-homogenization unit. It receives the initial Gaussian beam output by the laser, diffuses and disperses the beam, completes the first homogenization, destroys the original Gaussian energy concentration distribution characteristics of the beam, reduces the spatial coherence of the beam, and obtains a pre-homogenized beam with initially uniform energy distribution.

[0019] Based on the above scheme, the bundled fiber optic conduit further adopts an eccentric annular light-emitting structure.

[0020] Based on the above scheme, the focusing lens group is further composed of a first focusing lens and a second focusing lens connected together.

[0021] Based on the above scheme, the focusing coupling lens group is further composed of a focusing coupling first lens and a focusing coupling second lens connected together.

[0022] Based on the above scheme, the bundled fiber optic conduit is further described as a quartz capillary tube fitted with a small-core quartz fiber.

[0023] The focusing lens group is an ultraviolet fused silica lens group, used to receive the pre-homogenized beam output from the homogenizing module a, focus and shape the diverging beam, and accurately project the beam onto the incident end face of the homogenizing module b, ensuring that the beam fully covers the effective light transmission area of ​​the integrating rod, while adjusting the energy density of the incident light spot to protect the core homogenizing device.

[0024] The homogenizing module b is a square or polygonal solid ultraviolet fused silica integrating rod, which is the core homogenization unit of this invention. It is used to receive the pre-shaped beam output by the focusing lens group and complete the beam aliasing homogenization through multiple continuous total internal reflections through the inner wall of the integrating rod, effectively eliminating beam energy distribution differences, central hot spots and speckle noise, and outputting an ideal flat-top uniform beam spot, thus completing the second high-precision homogenization.

[0025] The focusing coupling lens group consists of coaxially symmetrically arranged ultraviolet fused silica plano-convex lenses, which are used to receive the flat-top uniform beam output by the integrating rod, scale and collimate the beam, match the beam spot size and incident angle to the incident end of the fiber optic tube, reduce beam divergence loss, and achieve precise focusing coupling.

[0026] The incident end of the bundled fiber optic catheter adopts a polygonal surface structure that is completely consistent with the exit surface of the integrating bar, achieving a precise 1:1 surface matching coupling, significantly improving the beam filling factor and reducing coupling loss; the exit end of the bundled fiber adopts a ring layout structure, which can be adapted to both concentric and eccentric arrangements to meet the needs of different clinical ablation scenarios.

[0027] Furthermore, the present invention adopts a coaxial straight cylindrical optical path structure without redundant reflector structure. With the central axis of the laser output port as the central axis of the overall optical path, all optical components are coaxially arranged to form an integrated cage-like fixed structure. This structure is simple to assemble and adjust, compact, and has strong optical path stability, effectively avoiding spot distortion and energy loss caused by optical path offset.

[0028] Furthermore, the laser is a semiconductor-pumped ultraviolet laser with an output wavelength of 300nm~400nm ultraviolet light, free from 1064nm and 532nm stray light interference, and its beam parameters are stable and controllable. The laser output beam pulse width is 8ns~15ns, the repetition frequency is 25Hz~150Hz, the spot diameter is 4mm~12mm, and the single pulse energy can reach 50mJ~150mJ. Precise single pulse energy control can be achieved through an external main controller, adapting to the ablation needs of different types of lesions such as fibrous plaques and lipid plaques. Compared to traditional excimer lasers, this laser does not require a long preheating time and can operate stably immediately upon startup. The equipment is smaller, less expensive, and consumes less energy, making it suitable for emergency and critical surgery scenarios.

[0029] Furthermore, the cross-section of the integrating rod of the homogenizing module b can be any one of square, rectangular, or regular hexagonal, and the material is high-transmittance ultraviolet fused silica. It has the characteristics of high temperature resistance, laser damage resistance, aging resistance, shock resistance, and displacement resistance. It can withstand high-power ultraviolet laser irradiation for a long time without ablation or deformation, and is almost maintenance-free. Its service life is far superior to that of traditional homogenized optical fiber.

[0030] Furthermore, the polygonal incident end face of the bundled fiber optic conduit is perfectly matched with the exit face of the integrating bar, which greatly improves energy utilization compared to the traditional circular fiber coupling structure. The conduit adopts a pluggable positioning structure with matching positioning grooves and positioning posts, which makes it easy to assemble and disassemble, and provides precise positioning, and is compatible with various minimally invasive interventional surgical instruments.

[0031] Furthermore, when the bundled fiber optic catheter adopts an eccentric annular light-emitting structure, the ablation fiber can be rotated to drive the laser ablation coverage area to expand significantly. There is no need to repeatedly adjust the catheter position, and the circumferential plaque ablation can be completed in a single positioning, effectively improving the efficiency of surgical ablation.

[0032] In the embodiments of this application, the beam uniformity is significantly superior. Traditional fiber optic mode transmission cannot eliminate Gaussian energy distribution, resulting in prominent hot spots at the center of the beam and poor uniformity. This invention can output a standard flat-top beam with uniform energy distribution, regular edges, and no local energy accumulation, thus avoiding vascular thermal damage and device ablation from the source. It effectively eliminates optical interference defects. Traditional fiber optic transmission inevitably produces mode noise, interference speckle, and lateral energy redistribution, which are the core reasons for device damage and uneven ablation. The integrating rod of this invention is a mode-free transmission device, which greatly reduces the spatial coherence of the beam and eliminates speckle, noise, and energy redistribution problems in principle, significantly improving the optical path transmission quality.

[0033] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention is the first to employ a diffuse pre-homogenization + square / polygonal integrating rod secondary homogenization method to transform the Gaussian beam into a highly uniform flat-top beam. The incident end of the combined fiber adopts a polygonal surface matching coupling consistent with the exit surface of the integrating rod, significantly improving coupling efficiency. This invention effectively solves the inherent defects of traditional fiber homogenization: concentrated hot spots, heavy speckle, high mode noise, easy ablation, and low coupling efficiency. Compared with fiber homogenization, it has outstanding advantages such as higher uniformity, stronger power tolerance, more regular beam, lower loss, and more stable system, greatly improving the safety and efficiency of laser ablation.

[0034] 2. This invention optimizes beam output quality and improves surgical safety; by using a composite uniform beam architecture to output a flat-top laser spot that is free of hot spots and speckles, it effectively solves the problems of uneven energy and local overheating in traditional beams, effectively avoids surgical complications such as thermal damage to blood vessel walls and microvascular embolism, and significantly improves the targeting accuracy and safety of laser ablation surgery.

[0035] 3. This invention improves plaque ablation efficiency and shortens operation time. The regular and controllable flat-top light spot can achieve full coverage and uniform ablation of vascular plaques without ablation blind spots. Combined with the eccentric annular light-emitting structure, it expands the ablation coverage area, reduces repeated ablation operations, significantly improves operation efficiency, and buys time for emergency and critically ill patients.

[0036] 4. This invention enhances equipment operational stability and reduces maintenance costs. By using a solid integrating rod to replace traditional vulnerable optical fibers, it effectively solves problems such as fiber core burning, aging, breakage, and high loss. This significantly reduces equipment failure rates, extends service life, eliminates the need for frequent component replacements, and effectively reduces maintenance investment in clinical equipment.

[0037] 5. This invention improves laser energy utilization and reduces energy consumption. The polygonal surface-type precise coupling structure significantly reduces optical path transmission loss, substantially improves the effective utilization rate of laser energy, reduces the workload of the laser and the energy consumption of the equipment, and further enhances the long-term stability of the system.

[0038] 6. This invention has strong structural versatility and high clinical application value. The optical path structure of this invention is compact, easy to assemble and adjust, and widely adaptable. It is compatible with various vascular interventional laser ablation devices, meeting the clinical needs of different lesion types and surgical scenarios, and possesses extremely high clinical application and market promotion value. Attached Figure Description

[0039] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a laser output device provided in an embodiment of this application; Figure 2 This is a schematic diagram of the specific structure of the laser output device provided in the embodiments of this application; Figure 3 This is a diagram of the incident end face of the bundled optical fiber provided in an embodiment of this application; Figure 4 This is a diagram of the output end face of the bundled optical fiber provided in an embodiment of this application; Figure 5 This is a surface profile diagram of the integrator bar end face provided in an embodiment of this application; In the diagram: 10, laser; 20, homogenizing module a; 30, focusing lens group; 301, first focusing lens; 302, second focusing lens; 40, homogenizing module b; 401, square cross-section; 402, regular hexagonal cross-section; 50, focusing coupling lens group; 501, first focusing coupling lens; 502, second focusing coupling lens; 60, bundled fiber optic conduit; 601, small-core quartz fiber; 602, quartz capillary. Detailed Implementation

[0041] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention. Example 1

[0042] This embodiment provides a novel uniform-light mode laser ablation system. The system adopts a coaxial straight-cylinder integrated cage structure, with the central axis of the laser output port as the optical path reference axis. No reflectors are set throughout the entire process, and all optical components are coaxially fixed and assembled along the optical path.

[0043] Please see Figures 1 to 2As shown, the overall optical path arrangement in this embodiment is arranged sequentially along the laser propagation direction as follows: semiconductor pumped ultraviolet laser 10, homogenizing module a20, focusing lens group 30, homogenizing module b40, focusing coupling lens group 50, and fiber optic cable 60.

[0044] Specifically, after the laser 10 is started, it outputs a Gaussian-distributed 355nm ultraviolet parallel initial beam. The initial beam is first incident on the homogenizing module a20 to complete the diffuse pre-homogenization, which initially disrupts the Gaussian energy distribution and transforms the parallel beam into a diffuse beam. The pre-homogenized diffuse beam passes through the focusing lens group 30, which may include a first focusing lens 301 and a second focusing lens 302. The first focusing lens 301 is a plano-convex lens, and the second focusing lens 302 is a plano-convex lens. The convex surfaces of the first focusing lens 301 and the second focusing lens 302 are arranged opposite to each other and coaxially. The pre-homogenized beam obtained after diffusion by the homogenization module a20 passes through the focusing lens group 30 to obtain the target beam. The target beam is vertically focused and incident on the incident end of the square integrating rod 40. Therefore, the focusing lens group 30 and the square integrating rod 40 need to be coaxially set. The beam is homogenized twice with high precision through continuous total internal reflection inside the integrating rod, and is transformed into a highly uniform flat-top beam. The flat-top beam passes through the focusing coupling lens group 50, which specifically includes a focusing coupling first lens 501 and a focusing coupling second lens 502. The focusing coupling first lens 501 and the focusing coupling second lens 502 are plano-convex lenses. The convex surfaces of the focusing coupling first lens 501 and the focusing coupling second lens 502 are set opposite to each other and placed coaxially. After passing through the focusing coupling lens group 50, the flat-top beam is further collimated and scaled, and then coupled into the medical optical fiber in the bundled fiber optic conduit 60 in a surface matching manner. Finally, the laser beam is output from the front end of the conduit and acts on the atherosclerotic plaque inside the blood vessel.

[0045] Specifically, the aforementioned focusing first lens 301, focusing second lens 302, focusing coupling first lens 501, and focusing coupling second lens 502 can all be lenses whose applicable wavelength range covers the aforementioned ultraviolet laser wavelength. As a preferred embodiment, all of the above lenses are ultraviolet fused silica lenses.

[0046] Specifically, a solid 401 integral bar with a square cross-section is used. The material is ultraviolet fused silica, for example, but not limited to a square with a side length of 4mm and a bar length of 80mm.

[0047] Specifically, the optical fiber input end is designed with a square face, consisting of a bundle of small-core silica optical fibers 601. Multiple small-core silica optical fibers 601 are completely fitted and matched to the output surface of the integrating rod. A silica capillary 602 is used to bundle the small-core silica optical fibers 601. The beam fill factor of the small-core silica optical fibers is ≥82%, and the coupling loss is ≤18%. Example 2

[0048] Please see Figures 3 to 5 As shown, this embodiment is basically the same as embodiment 1 in structure. The only difference is the cross-sectional shape and size of the uniform light module b40 and the end face structure of the bundled fiber. The other device models, optical path spacing and optical parameters remain unchanged.

[0049] Specifically, a solid 402 integrating rod with a regular hexagonal cross section is used. The material is still ultraviolet fused silica, for example, but not limited to, a regular hexagonal circumcircle diameter of 8mm and a rod length of 80mm. After total internal reflection homogenization, the output light spot outline is a regular hexagon with regular edges.

[0050] Specifically, the fiber optic input end is designed with a regular hexagonal surface, formed by bundling together small-core silica fibers 601. Multiple small-core silica fibers 601 are perfectly fitted and matched to the output surface of the integrating rod. A silica capillary tube 602 is used to bundle the small-core silica fibers 601. The beam fill factor of the small-core silica fibers is ≥81%, and the coupling loss is ≤19%. The fiber optic output end adopts an eccentric annular layout, and the guide tube can be externally connected to a rotation drive mechanism.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel uniform-mode laser ablation system, characterized in that, The system includes a laser, a homogenizing module a, a focusing lens group, a homogenizing module b, a focusing coupling lens group, and a beam combiner arranged coaxially along the optical path. The homogenizing module a is a diffuser or a holographic homogenizing plate. The homogenizing module b is a solid integrating rod. The incident end of the beam combiner is designed to match the shape and size of the exit surface of the homogenizing module b.

2. The system according to claim 1, characterized in that, The uniform light module b is a solid ultraviolet fused silica integrating rod with a rectangular or regular hexagonal cross-section.

3. The system according to claim 1, characterized in that, The incident end face of the bundled fiber optic conduit is polygonal, with a fill factor ≥80% and a coupling loss ≤20%.

4. The system according to claim 1, characterized in that, The overall optical path has a coaxial straight cylindrical structure.

5. The system according to claim 1, characterized in that, The laser is a semiconductor-pumped ultraviolet laser with an output wavelength of 300nm~400nm ultraviolet laser; the output beam pulse width is 8ns~15ns, the repetition frequency is 25Hz~150Hz, the spot diameter is 4mm~12mm, and the single pulse energy is 50mJ~150mJ.

6. The system according to claim 1, characterized in that, The bundled fiber optic conduit adopts an eccentric annular light-emitting structure.

7. The system according to claim 1, characterized in that, The focusing lens group consists of a first focusing lens and a second focusing lens connected together.

8. The system according to claim 1, characterized in that, The focusing coupling lens group consists of a first focusing coupling lens and a second focusing coupling lens connected together.

9. The system according to claim 1, characterized in that, The fiber optic cable is a quartz capillary tube fitted with a small-core quartz optical fiber.

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