Method and system for inducing pulsed water jet to mediate laser ablation of biological hard tissue through ultrasonic waves

Abstract

The invention relates to a method and a system for laser ablation of biological hard tissue based on ultrasonic-induced pulsed water jet. The system mainly comprises an ultrasonic system, a water supply system, an air supply system, a laser transmission system, an optical fiber fixing system and a waste liquid recovery system. Ultrasonic waves are adopted to induce pulse water jet to be coaxial with the hollow optical fiber, gas with a certain pressure intensity is introduced into the hollow optical fiber, and a laser beam is reflected into the hollow optical fiber through a reflector to be coupled and then acts on biological hard tissue. Water transmitted by the water supply system passes through the water cavity and flows to a laser ablation area along the outer wall of the optical fiber, the ultrasonic system generates vibration through a transducer to drive water flow to form pulsating water jet to impact the surface of the ablation area, and the water jet is helpful to enter a narrow kerf under the pulsating effect and is helpful to discharge ablation debris. Therefore, large-depth and high-quality drilling and slotting of biological hard tissues can be realized. Meanwhile, the air supply system controls the thickness of a water layer in a laser acting area on the surface of the bone tissue by introducing gas with certain pressure through the center of the hollow optical fiber, so that the water layer is prevented from greatly absorbing the laser, and high ablation efficiency is ensured. According to the invention, large depth, high ablation efficiency and high cooling efficiency can be simultaneously realized in laser ablation of biological hard tissues.

Description

Technical Field

[0001] The present invention uses ultrasonic induction to generate vibrations through a transducer to drive the water flow guided by the optical fiber wall to form a pulsed water jet to impact the surface of the ablation area. The water jet helps to enter the narrow slit under the action of periodic pulses and is conducive to the discharge of ablation debris. At the same time, the gas supply system controls the thickness of the water layer in the laser action area on the surface of the bone tissue by passing a certain pressure of gas through the center of the hollow optical fiber, thereby avoiding the large absorption of the laser by the water layer and ensuring a high ablation efficiency. The above method forms a laser ablation system for biological hard tissue that can achieve large depth, high efficiency ablation and low thermal damage. Background Art

[0002] Water is often used for cooling in the field of laser ablation of biological hard tissues, but how to use water for efficient cooling during deep ablation is one of the keys to clinical applications. Ultrasonic transducers can convert electrical energy into mechanical vibrations. By controlling the ultrasonic input parameters through an ultrasonic generator to modulate the pulsed water jet, the ability of water to enter narrow slits is greatly enhanced, thereby improving cooling efficiency. At the same time, the pulsed water jet has a periodic impact on the target material, thereby improving the efficiency of water flushing the ablation residue.

[0003] Based on the above considerations, this patent designs a method and system for laser ablation of biological hard tissue that can achieve deep ablation while ensuring efficient ablation and efficient cooling. Summary of the invention

[0004] This patent proposes a method and system for laser ablation of biological hard tissues by guiding ultrasonic pulsed water jets attached to the fiber wall. The characteristics are that water-assisted cooling technology, ultrasonic actuation technology, gas-assisted technology and laser ablation technology are combined. The present invention adopts the method of guiding water flow through the outer wall of the hollow fiber through the ventilation center of the hollow fiber and applying ultrasonic actuation water flow at the same time. The structure reflects the laser into the hollow fiber through a reflector for coupling, and then acts on the biological hard tissue. The water supply system transmits water through the water cavity along the outer wall of the fiber to the laser ablation area. The ultrasonic system transmits a signal to the transducer to vibrate to drive the fiber wall to guide the water flow to form a pulsating water jet to impact the surface of the ablation area. The water jet helps to enter the narrow slit under the action of pulsation, and is conducive to the discharge of ablation debris. At the same time, the gas supply system passes a certain pressure gas through the center of the hollow fiber to reduce the thickness of the water layer in the laser action area on the surface of the bone tissue, reducing the absorption of the laser by the water layer and ensuring high ablation efficiency.

[0005] In order to achieve the above effects, this patent adopts the following technical methods:

[0006] A method and system for ultrasonic-induced pulsed water jet-mediated laser ablation of biological hard tissues comprises a laser transmission system, an ultrasonic system, a water supply system, an air supply system, an optical fiber fixing system and a waste liquid recovery system.

[0007] The laser transmission system includes a laser, a focusing lens, a reflector, a hollow optical fiber, and an optical coupling system in sequence; the system adopts an Er:YAG laser generator with a wavelength of 2940nm, and utilizes the high absorption rate of Er:YAG laser to the main components of biological hard tissues such as hydroxyapatite, so as to obtain a higher ablation efficiency of biological hard tissues; the focusing lens is used to focus the parallel laser beam generated by the laser onto the reflector; the reflector couples the laser into a fixed optical fiber, the hollow optical fiber is used to accurately couple and transmit the laser through the central through hole of the optical fiber, and the optical coupling system is a single focusing lens or a coupling lens group composed of a concave lens and a focusing lens to diverge and converge the laser, thereby achieving the effect of accurately transmitting the laser.

[0008] The ultrasonic system includes an ultrasonic generator and a transducer. The input signal of the ultrasonic generator causes the ultrasonic coupling cavity containing the transducer, bolts and other structures to vibrate, generating resonance to drive the oscillation of the water flow attached to the optical fiber wall. After the oscillating fluid passes through the nozzle outlet, a strong pulse cavitation jet is formed.

[0009] The water supply system includes a water tank, a flow sensor, a flow regulating valve, a filter device, and a water suction pump. The water suction pump sucks water out of the water tank, obtains pure water through the filter device, and adjusts the water flow through the flow regulating valve.

[0010] The air supply system includes an air compressor, a pressure regulating valve, and an air pressure sensor. The pressure regulating valve is adjusted according to the parameters provided by the air pressure sensor to control the air compressor to supply air to the air cavity of the optical fiber fixing device.

[0011] The optical fiber fixing system comprises an air cavity, an outer bolt, an optical fiber fixing bolt, an outer shell, a gasket and a lower nozzle.

[0012] The waste liquid recovery system includes a water suction pump, a filter device, and a water tank. The waste water purified by the filter device is recovered to the water tank through the water suction pump for easy treatment.

[0013] A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue, comprising the following steps:

[0014] 1. Start the water supply system. The water supply system obtains the required water inlet flow and generates a stable water flow by adjusting the flow control valve. After being transmitted through the pipeline, the water enters the water cavity. After reaching the threshold, it reaches the area to be ablated along the outer wall of the hollow optical fiber.

[0015] 2. Start the waste liquid recovery system to absorb, filter and discharge the accumulated water and residue in the ablation area in real time.

[0016] 3. Start the air supply system, which transmits compressed air to the air cavity and acts on the ablation area through the central hole of the hollow optical fiber, reducing the concentration and stagnation time of water in the ablation area and reducing the absorption of water on the Er:YAG laser. It can also blow away the remaining residues of ablation in time, reduce thermal accumulation damage and clean the ablation area.

[0017] 4. Turn on the ultrasonic system. The ultrasonic system generates vibrations through the transducer to drive the water flow to form a pulsating water jet to impact the surface of the ablation area. The pulsating action of the water jet helps it enter the narrow incision and is conducive to the discharge of ablation debris.

[0018] 5. Start the laser to emit laser; transmit the laser beam to the reflector through the focusing lens, and the reflector couples the laser light into the central hole of the hollow optical fiber through the concave and convex lens group, and the end of the hollow optical fiber is close to the ablation area; while the laser ablates the biological hard tissue, water rushes to the ablation area in time for timely and effective cooling, and at the same time, compressed air acts on the ablation surface through the inner hole of the optical fiber, which plays a role in thinning and homogenizing the water layer, and can blow away the ablation residue, thereby improving the ablation efficiency and cleaning the ablation surface.

[0019] 6. After ablation is completed, turn off the laser first, then turn off the ultrasonic system, then turn off the air supply system, and finally turn off the water outlet in the hydraulic system. After ensuring that there is no excess water in the ablation area, turn off the water suction device to ensure the cleanliness of the ablation area.

[0020] The present invention has the following beneficial effects:

[0021] 1. The method and system of the ultrasonic-induced pulsed water jet-mediated laser ablation of biological hard tissue of the present invention are characterized in that they can be applied to a variety of laser ablation occasions, and are not limited to the type of optical fiber, and are widely used. This patent adopts an Er:YAG laser generator with a wavelength of 2940nm.

[0022] 2. The method and system of the present invention for laser ablation of biological hard tissue mediated by ultrasonically induced pulsed water jet is characterized in that during the laser ablation of biological hard tissue, after the action of the ultrasonically induced water jet pulse, the water jet helps to enter the narrow incision under the pulsating action and is beneficial to the discharge of ablation debris.

[0023] 3. The method and system of the present invention for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue is characterized in that the cooling effect of the pulsed water flow can effectively control the temperature of the target material and reduce the range of the heat-affected zone.

[0024] 4. The method and system of the ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue of the present invention are characterized by the use of hollow optical fiber, which can better thin and homogenize the water layer in the ablation area on the surface of biological hard tissue where the Er:YAG laser acts. Since water has a large absorption of Er:YAG laser, this method can effectively reduce the absorption of Er:YAG laser by water and improve the ablation efficiency.

[0025] 5. The method and system of the present invention for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue is characterized in that the pulsed water flow has a strong impact force and can enter narrower incisions and holes, thereby achieving effective cooling of biological hard tissue at a greater depth during the ablation process.

[0026] 6. The method and system of the present invention for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue is characterized in that the pulsed water flow has a pulsating impact force, which can facilitate the discharge of ablation debris during the ablation process of the biological hard tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the overall structure of a method and system for ultrasonic-induced pulsed water jet-mediated laser ablation of biological hard tissue in Example 1 of the present invention

[0028] Description of Reference Numerals Laser—1, focusing lens—2, reflector—3, concave lens—4, convex lens—5, air pressure sensor—6, pressure regulating valve—7, air compressor—8, flow sensor—9, flow regulating valve—10, medical pump—11, filter device—12, water tank—13, ultrasonic generator—14, air cavity—15, outer bolt—16, optical fiber fixing bolt—17, housing—18, gasket—19, transducer—20, lower nozzle—21, hollow optical fiber—22, workbench—23, filter device—24, water suction pump—25, waste water tank—26. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Example 1

[0031] The invention discloses a method and system for ultrasonic-induced pulsed water jet-mediated laser ablation of biological hard tissue, comprising a laser transmission system, an ultrasonic system, a water supply system, an air supply system, an optical fiber fixing system and a waste liquid recovery system.

[0032] The laser transmission system includes a laser 1, a focusing lens 2, a reflector 3, a concave lens 4, a convex lens 5, and a hollow optical fiber 22. Figure 1 As shown, the laser beam emitted by the laser 1 is transmitted to the reflector 3 through the focusing lens 2. The reflector 3 projects the laser to the concave lens 4 through a specific reflection angle for divergence, and then is focused by the convex lens 5. After the transmission process, the laser beam is coupled into the inner hole of the hollow optical fiber 22. The laser energy is radiated to the surface to be ablated through the hollow optical fiber 22.

[0033] The air supply system includes an air pressure sensor 6, a pressure regulating valve 7, and an air compressor 8. Pure compressed air is introduced from the air compressor 8 into the air cavity through the air pipe, and the pressure regulating valve 7 can be used to obtain the required air pressure through the parameters reflected by the air pressure sensor 6.

[0034] The water supply system includes a flow sensor 9, a flow regulating valve 10, a medical pump 11, a filter device 12, and a water tank 13. The medical pump 11 draws pure water from the water tank 13, passes through the filter device 12, and then enters the water cavity for operation. At the same time, the flow regulating valve 10 can be adjusted according to the real-time data reflected by the flow sensor 9 to obtain the required flow rate.

[0035] The ultrasonic system includes an ultrasonic generator 14 and a transducer 20. The ultrasonic generator 14 emits an ultrasonic vibration signal which is transmitted to the transducer 20, and the transducer 20 converts electrical energy into mechanical energy to generate vibration.

[0036] The optical fiber fixing system includes an air cavity 15 , an outer bolt 16 , an optical fiber fixing bolt 17 , an outer shell 18 , a gasket 19 , and a lower nozzle 21 .

[0037] The waste liquid recovery system includes a filter device 24, a water suction pump 25, and a waste water tank 26. The waste water obtained after ablation is filtered through the filter device 25 by the water suction pump 24, and the purified waste water is sucked into the waste water tank 26, which is convenient for waste water classification treatment and recycling.

[0038] In the actual processing process, the steps are as follows: (1) Start the water supply system first, adjust the flow rate to the set parameters, and allow the outer wall of the hollow-core optical fiber 22 to obtain a stable water flow; (2) The waste liquid recovery system is turned on to collect the accumulated water and residues in the workbench 23 in real time; (3) Start the air supply system, transmit compressed air through the inner hole of the hollow-core optical fiber to the surface of the biological hard tissue to thin and homogenize the water layer. (4) Start the ultrasonic system, turn on the ultrasonic generator 14, and the transducer 20 starts to work and generates vibration. (5) Start the laser 1, and the laser is transmitted through the focusing lens 2, the reflector 3, the concave lens 4, and the convex lens 5 and then coupled with the hollow-core optical fiber. The laser energy acts on the surface of the biological hard tissue at the end of the hollow-core optical fiber 22 to ablate; (6) When the ablation is completed, first turn off the laser 1, then turn off the ultrasonic system, then turn off the air supply system, then turn off the water supply system, and finally turn off the waste liquid recovery system.

[0039] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. Any known variations such as various changes, modifications, substitutions and variations of these embodiments without departing from the principle and spirit of the present invention still fall within the technical scope to be protected by the present invention.

Claims

1. The present invention discloses a method and system for laser ablation of biological hard tissue mediated by ultrasonic-induced pulsed water jet, which mainly includes an ultrasonic system, a water supply system, an air supply system, a laser transmission system, an optical fiber fixing system and a waste liquid recovery system. The present invention adopts an ultrasonic-induced pulsed water jet to maintain coaxiality with a hollow optical fiber, and introduces a certain pressure gas into the hollow optical fiber. The laser beam is reflected into the hollow optical fiber through a reflector for coupling, and then acts on the biological hard tissue. The water supply system transmits water through the water cavity along the outer wall of the optical fiber to the laser ablation area. The ultrasonic system generates vibrations through the transducer to drive the water flow to form a pulsating water jet to impact the surface of the ablation area. The water jet helps to enter the narrow slit under the action of pulsation, and is conducive to the discharge of ablation debris, thereby achieving deep and high-quality drilling and slit of biological hard tissue. At the same time, the air supply system passes a certain pressure gas through the center of the hollow optical fiber to control the thickness of the water layer in the laser action area on the surface of the bone tissue, thereby avoiding the large absorption of the laser by the water layer and ensuring high ablation efficiency. The present invention can simultaneously achieve a large depth, high ablation efficiency and high cooling efficiency in laser ablation of biological hard tissue.

2. A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue according to claim 1, characterized in that An Er:YAG laser generator with a wavelength of 2940 nm is used but not limited thereto, and the laser is guided through a hollow optical fiber to reduce the attenuation of laser energy.

3. A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue according to claim 1, characterized in that The cooling effect of the pulsed water flow can effectively control the temperature of the target material and reduce the scope of the heat affected zone.

4. A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue according to claim 1, characterized in that By introducing a certain pressure of gas into the hollow optical fiber, the water layer in the ablation area on the surface of biological hard tissue can be thinned and homogenized better. Since water has a strong absorption of Er:YAG laser, this method can effectively reduce the absorption of Er:YAG laser by water and improve the ablation efficiency.

5. A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue according to claim 1, characterized in that The pulsed water flow has a strong impact force and can enter narrower incisions and holes, thereby achieving effective cooling of biological hard tissues at greater depths during the ablation process.

6. A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue according to claim 1, characterized in that The pulsed water flow has a pulsating impact force, which can facilitate the discharge of ablation debris during the ablation process of biological hard tissue.

7. A method and system for ultrasonically induced pulsed water jet-mediated laser ablation of biological hard tissue according to claim 1, characterized in that The steps to use are as follows: S1 turns on the water supply system, which obtains the required water inlet flow by adjusting the flow regulating valve and generates a stable water flow into the water cavity, flowing along the outer wall of the optical fiber to the tissue action area. S2 starts the waste liquid recovery system to absorb, filter and discharge the accumulated water and residue in the ablation area in real time; S3 turns on the air supply system, transmitting compressed air through the inner hole of the hollow optical fiber to the surface of the biological hard tissue to thin and homogenize the water layer. S4 turns on the ultrasonic system. The ultrasonic system generates vibrations through the transducer to form a pulsed water jet along the fiber wall to impact the surface of the ablation area. The water jet helps to enter the narrow incision under the periodic pulse impact, which is beneficial to the effective cooling of the ablation area at a large depth, and is beneficial to the discharge of ablation debris, thereby improving the ablation surface quality. S5 starts and controls the laser generating device, and the laser emits laser light; the laser beam is transformed into a large angle through a focusing lens and then coupled into the hollow optical fiber, and acts on the ablation area through optical fiber reflection transmission. After S6 ablation is completed, turn off the laser first and then the water outlet in the hydraulic system to ensure the cleanliness of the ablation area.

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