Mid-infrared high power femtosecond laser atherosclerotic tissue ablation device and method

Abstract

The application relates to the field of solid ultrafast laser technology, in particular to a kind of middle infrared high-power femtosecond laser atherosclerotic tissue ablation device and method, including the chirp pulse amplification module for generating high-power femtosecond pump light in signal light path; middle infrared femtosecond laser generation module for generating 5.75 microns middle infrared high-power laser through two-stage optical parametric amplification module; atherosclerotic ablation module for outputting 5.75 microns external high-power femtosecond laser to ablate atherosclerotic tissue. Atherosclerotic tissue can be removed efficiently, minimally invasively and selectively.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid-state ultrafast laser technology, in particular to a kind of middle infrared high-power femtosecond laser atherosclerotic tissue ablation device and method. BACKGROUND

[0002] Atherosclerosis is a layer of lipid deposition on the artery wall like millet gruel, which makes the artery elasticity decrease and the lumen narrow. Once it develops to block the artery lumen, the tissue or organ supplied by the artery will be ischemic or necrotic. The present treatment method mainly includes drug therapy, surgical treatment, traditional Chinese medicine treatment. Drug therapy mainly adjusts blood lipids, dilates blood vessels, controls blood pressure and prevents arterial embolism, but drug therapy is generally for relief, and cannot always quickly and effectively treat the lesion site, and often has side effects including but not limited to digestive symptoms, bleeding, elevated blood transaminase and creatine kinase levels, muscle discomfort and increased heart rate, etc.

[0003] Surgical treatment can be performed by balloon dilation, stent implantation and bypass grafting, etc. Surgical treatment has better effect than drug therapy, but has higher cost and risk, and postoperative drug therapy must be insisted, the lesion site cannot be eradicated, and some patients do not accept surgical treatment.

[0004] The middle infrared femtosecond laser has very high peak power and very small thermal damage, and there are many molecular resonance peaks in the middle infrared band. In biological medicine, it can selectively ablate the lesion site without damaging the surrounding normal human tissues. In the atherosclerotic area of the human body, the main substance is cholesterol ester. The ester bond in the chemical molecular formula of this substance has a very strong absorption peak at 5.75 microns of middle infrared wavelength. After laser irradiation, cholesterol ester is decomposed into free cholesterol and oleic acid, which can be metabolized by the human body. At the same time, at the wavelength of 5.75 microns, laser irradiation can effectively decompose the atherosclerotic plaque. The laser irradiation time is basically within 5s, which can effectively decompose the atherosclerotic components, and does not damage the nearby albumin and artery wall. Compared with the wavelength of 6.1 microns, 5.75 microns is a more ideal wavelength for removing atherosclerotic areas. The 6.1 micron wavelength will obviously damage the surrounding human albumin during irradiation. In summary, there is an urgent need for a middle infrared high-power femtosecond laser device and method for efficiently, minimally invasively and selectively removing atherosclerosis. SUMMARY

[0005] The present application aims to provide a kind of middle infrared high-power femtosecond laser atherosclerotic tissue ablation device and method, which can efficiently, minimally invasively and selectively remove atherosclerotic tissue.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] The application discloses a kind of middle infrared high-power femtosecond laser atherosclerotic tissue ablation device, including being sequentially arranged on signal light path on chirp pulse amplification module, for generating high-power femtosecond pump light;Middle infrared femtosecond laser generation module, for generating 5.75 microns middle infrared high-power femtosecond laser by two-stage optical parametric amplification module;Atherosclerotic ablation module, for outputting 5.75 microns middle infrared high-power femtosecond laser to atherosclerotic tissue and carrying out ablation.

[0008] Further, the chirp pulse amplification module includes a seed source, a first mirror, a first thin film polarizer, a first half-wave plate, a second mirror, a third mirror, a first bichromatic mirror, a first Yb:YAG crystal, a fourth mirror, a second half-wave plate, a second thin film polarizer, a second bichromatic mirror, a second Yb:YAG crystal, a fifth mirror, a third half-wave plate, a third thin film polarizer, a compressor, and a pump source, which are sequentially arranged along the input direction of the signal light path; the first bichromatic mirror and the second bichromatic mirror are respectively connected with the output light path of the pump source; the seed source is used to emit 40W femtosecond laser as a seed.

[0009] Further, the middle infrared femtosecond laser generation module includes a white light signal generation module, a signal light optical parametric amplification module, and an idler light optical parametric amplification module; the white light signal generation module is used to generate white light signals; the signal light optical parametric amplification module is used to receive and amplify the white light signals to obtain signal pulse light; and the idler light optical parametric amplification module is used to receive and amplify the signal pulse light to obtain middle infrared high-power femtosecond laser with a wavelength of 5.75 microns and a pulse width of 280 fs.

[0010] Further, the white light signal generation module includes a sixth mirror, a seventh mirror, a fourth half-wave plate, a fourth thin film polarizer, a YAG crystal, a first long-wave pass filter, an eighth mirror, and a ninth mirror, which are sequentially arranged along the input direction of the signal light path; the YAG crystal is used to self-phase modulate pump light to achieve spectral broadening.

[0011] Further, the signal light optical parametric amplification module includes a fifth half-wave plate, a fifth thin film polarizer, a tenth mirror, a third bichromatic mirror, a first LGS crystal, a second long-wave pass filter, an eleventh mirror, and a twelfth mirror, which are sequentially arranged along the input direction of the signal light path; the fourth thin film polarizer divides the high-power femtosecond pump light into the YAG crystal and the fifth half-wave plate; the third bichromatic mirror is used to receive white light signals and combine with the high-power femtosecond pump light.

[0012] Further, the idler light optical parametric amplification module comprises a 13th mirror, a 14th mirror, a fourth dichroic mirror, a second LGS crystal and a germanium sheet arranged in sequence along the input direction of the signal light path.

[0013] Further, the atherosclerosis ablation module comprises a 15th mirror, a 16th mirror and a zinc selenide convex lens arranged in sequence along the input direction of the signal light path.

[0014] Further, the light guide ablation component is a CaF2 window sheet or an optical fiber.

[0015] A method for using a mid-infrared high-power femtosecond laser atherosclerosis tissue ablation device, based on the mid-infrared high-power femtosecond laser atherosclerosis tissue ablation device, comprising the following steps:

[0016] S1: Pump the first-stage Yb:YAG crystal and the second-stage Yb:YAG crystal to the excited state by the pump source of the chirped pulse amplification module; at the same time, output 135W laser with a wavelength of 1030nm through the first-stage Yb:YAG crystal and the second-stage Yb:YAG crystal by taking the 40W femtosecond laser generated by the seed source as the seed; then output high-power femtosecond pump light after pulse compression by the compressor;

[0017] S2: Perform self-phase modulation and spectral broadening on the high-power femtosecond pump light generated by the chirped pulse amplification module to obtain a broadband white light signal by the white light signal generation module; after receiving the white light signal, the signal light optical parametric amplification module combines with the high-power femtosecond pump light, performs first-stage optical parametric amplification, and then filters out the high-power femtosecond pump light to obtain amplified signal pulse light;

[0018] S3: After combining the signal pulse light with the high-power femtosecond pump light by the idler light optical parametric amplification module, perform second-stage optical parametric amplification on the generated idler light, filter out the high-power femtosecond pump light to obtain 5.75-micron, 280-fs pulse-width mid-infrared high-power femtosecond laser;

[0019] S4: Focus the received mid-infrared high-power femtosecond laser to different spot sizes by the zinc selenide convex lens; then guide it into the atherosclerosis tissue for ablation by the light guide ablation component.

[0020] Further, the ablation by the light guide ablation component includes ablation by a CaF2 window piece or a fiber to guide light to the lesion area to remove the plaque efficiently.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] 1. The present application provides a kind of middle infrared high power femtosecond laser atherosclerotic tissue ablation device and method, using 5.75 microns specific wavelength to human atherosclerotic tissue to achieve the effect of high efficiency selective ablation.

[0023] 2. The present application can remove plaque efficiently by CaF2 window piece or fiber to guide light to the lesion area.

[0024] 3. The present application can irradiate without damaging the surrounding human protein and artery wall, achieving the effect of minimally invasive. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present application, but not limit the present application.

[0026] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0027] Figure 2 It is the infrared spectrum and microscope image under different parameters of the present application;

[0028] Figure 3 It is the protein absorption spectrum and artery injury section image under different parameters of the present application;

[0029] Figure 4 It is the Raman spectrum result graph excited by 532nm after irradiation by laser parameters of 5.75 microns 210mw power 1000 microns spot;

[0030] Figure 5 It is the power output graph of the present application;

[0031] Figure 6 It is the spectrum comparison graph when the output wavelength of the present application is 5.75 microns and 6.1 microns.

[0032] Wherein, 1-seed source, 2-the first mirror, 3-the first film polarizer, 4-the first half-wave plate, 5-the second mirror, 6-the third mirror, 7-the first dichroic mirror, 8-the first Yb:YAG crystal, 9-the fourth mirror, 10-the second half-wave plate, 11-the second film polarizer, 12-the second dichroic mirror, 13-the second Yb:YAG crystal, 14-the fifth mirror, 15-the third half-wave plate, 16-the third film polarizer, 17-compressor, 18-pump source, 19-the sixth mirror, 20-the seventh mirror, 21-the fourth half-wave plate, 22-the fourth film polarizer, 23-YAG crystal, 24-the first long-wave pass filter, 25-the eighth mirror, 26-the ninth mirror, 27-the third dichroic mirror, 28-the fifth half-wave plate, 29-the fifth film polarizer, 30-the tenth mirror, 31-the first LGS crystal, 32-the second long-wave pass filter, 33-the 11th mirror, 34-the 12th mirror, 35-the fourth dichroic mirror, 36-the 13th mirror, 37-the 14th mirror, 38-the second LGS crystal, 39-germanium sheet, 40-the 15th mirror, 41-the 16th mirror, 43-zinc selenide convex lens, 44-analog blood vessels, 45-peristaltic pump 45, 46-the 17th mirror, 47-the second zinc selenide convex lens, 48-CaF2window sheet, 49-mid-infrared spectrometer, 50-the 18th mirror, 51-the third zinc selenide convex lens, 52-the 19th mirror, 53-the second CaF2window sheet, 54-Raman spectrometer. DETAILED DESCRIPTION

[0033] The application will be further described below through specific examples:

[0034] Reference Figure 1 , 5 , 6, a kind of mid-infrared high-power femtosecond laser atherosclerotic tissue ablation device, including sequentially arranged on the signal light path Chirp pulse amplification module, for generating high-power femtosecond pump light;Mid-infrared femtosecond laser generation module, for generating 5.75 microns mid-infrared high-power laser by two-stage optical parametric amplification module;Atherosclerotic ablation module, for outputting 5.75 microns external high-power femtosecond laser to atherosclerotic tissue ablation.

[0035] The chirped pulse amplification module comprises a seed source 1, a first mirror 2, a first film polarizer 3, a first half-wave plate 4, a second mirror 5, a third mirror 6, a first dichroic mirror 7, a first-stage Yb:YAG crystal 8, a fourth mirror 9, a second half-wave plate 10, a second film polarizer 11, a second dichroic mirror 12, a second-stage Yb:YAG crystal 13, a fifth mirror 14, a third half-wave plate 15, a third film polarizer 16, a compressor 17 and a pump source 18, which are sequentially arranged along an input direction of a signal light path; the first dichroic mirror 7 and the second dichroic mirror 12 are connected with two ends of an output light path of the pump source 18 respectively; and the seed source 1 is used for emitting 40W femtosecond laser as a seed.

[0036] The mid-infrared femtosecond laser generation module comprises a white light signal generation module, a signal light optical parametric amplification module and an idler light optical parametric amplification module; the white light signal generation module is used for generating a white light signal; the signal light optical parametric amplification module is used for receiving and amplifying the white light signal to obtain signal pulse light; and the idler light optical parametric amplification module is used for receiving and amplifying the signal pulse light to obtain a 5.75-micron mid-infrared high-power femtosecond laser with a pulse width of 280fs.

[0037] The white light signal generation module comprises a sixth mirror 19, a seventh mirror 20, a fourth half-wave plate 21, a fourth film polarizer 22, a YAG crystal 23, a first long-wave pass filter 24, an eighth mirror 25 and a ninth mirror 26, which are sequentially arranged along an input direction of a signal light path; and the YAG crystal 23 is used for self-phase modulation of pump light to achieve spectral broadening.

[0038] The signal light optical parametric amplification module comprises a fifth half-wave plate 28, a fifth film polarizer 29, a tenth mirror 30, a third dichroic mirror 27, a first LGS crystal 31, a second long-wave pass filter 32, an eleventh mirror 33 and a twelfth mirror 34, which are sequentially arranged along an input direction of a signal light path; the fourth film polarizer 22 is used for splitting high-power femtosecond pump light to the YAG crystal 23 and the fifth half-wave plate 28; and the third dichroic mirror 27 is used for receiving white light signals and combining with high-power femtosecond pump light.

[0039] The idler light optical parametric amplification module comprises a thirteenth mirror 36, a fourteenth mirror 37, a fourth dichroic mirror 35, a second LGS crystal 38 and a germanium sheet 39, which are sequentially arranged along an input direction of a signal light path; the fifth film polarizer 29 is used for splitting high-power femtosecond pump light to the tenth mirror 30 and the thirteenth mirror 36; and the fourth dichroic mirror 35 is used for receiving signal pulse light and combining with high-power femtosecond pump light.

[0040] The atherosclerosis ablation module comprises a 15th mirror 40, a 16th mirror 41, a zinc selenide convex lens 43 and a light guide ablation component arranged in sequence along the input direction of the signal light path.

[0041] A method for using a mid-infrared high-power femtosecond laser atherosclerosis tissue ablation device, based on the above-mentioned mid-infrared high-power femtosecond laser atherosclerosis tissue ablation device, comprising the following steps:

[0042] S1: Pump the first Yb:YAG crystal and the second Yb:YAG crystal to the excited state by the pump source of the chirped pulse amplification module; at the same time, generate 40W femtosecond laser as a seed by the seed source, output the laser with a power of 135W and a wavelength of 1030nm through the first Yb:YAG crystal and the second Yb:YAG crystal, and then output high-power femtosecond pump light after pulse compression by the compressor;

[0043] S2: Perform self-phase modulation and spectral broadening on the high-power femtosecond pump light generated by the chirped pulse amplification module to obtain a broadband white light signal by the white light signal generation module; after receiving the white light signal, the signal light optical parametric amplification module combines with the high-power femtosecond pump light, performs first-stage optical parametric amplification, and then filters out the high-power femtosecond pump light to obtain amplified signal pulse light;

[0044] S3: After combining the signal pulse light with the high-power femtosecond pump light by the idler light optical parametric amplification module, perform second-stage optical parametric amplification on the generated idler light, filter out the high-power femtosecond pump light, and obtain a 5.75-micron, 280-fs pulse-width mid-infrared high-power femtosecond laser;

[0045] S4: Focus the received mid-infrared high-power femtosecond laser to different spot sizes by a zinc selenide convex lens; then introduce the mid-infrared high-power femtosecond laser into the atherosclerosis tissue through a light guide ablation component for ablation.

[0046] The ablation of the atherosclerosis tissue by the light guide ablation component includes introducing the mid-infrared high-power femtosecond laser into the plaque site for ablation through a CaF2 window piece or using an optical fiber attached to the inside of the puncture needle to guide the mid-infrared high-power femtosecond laser to the atherosclerosis tissue for ablation.

[0047] Design a living flow device, test the infrared transmission spectrum, and test the Raman spectrum to analyze the effects of different parameters of the mid-infrared high-power femtosecond laser atherosclerosis tissue ablation device. Figure 2As shown, the first row of infrared spectra at the focal wavelength of 5.75 μm (80 mW, 130 mW, and 210 mW) reveals the disappearance of absorption at 210 mW, indicating the decomposition of the plaque material. The second row of infrared spectra at 2500 μm, 1500 μm, and 1000 μm, corresponding to a 5.75 μm 210 mW spot, shows the absorption peak gradually disappearing as the spot size decreases, until it completely disappears at a 1000 μm spot, further indicating the decomposition of the plaque material. The third row of microscopic images at the focal wavelength of 5.75 μm (80 mW, 130 mW, and 210 mW) confirms the results.

[0048] like Figure 3 As shown, the first row corresponds to protein absorption spectra, irradiated with a 300mw 5.75μm laser and an 80mw 6.1μm laser. Damage from the 6.1μm laser is clearly visible, while no damage is observed from the 5.75μm laser. The second row corresponds to a 5.75μm 300mw arterial injury slice. The average damage at the focal point is only 23μm, and no significant damage is observed when the spot size is increased to 700μm.

[0049] like Figure 4 As shown, after irradiation, the peak value of C=O shifted from the peak of 1740cm-(1) corresponding to cholesterol ester to the peak of 1710cm-(1) corresponding to oleic acid, which confirms that the cholesterol ester in the plaque was effectively decomposed.

[0050] The living flow device includes a simulated blood vessel and a peristaltic pump. After simulating the actual thickness of the human plaque and the actual blood flow, a 5.75-micron mid-infrared high-power femtosecond laser ablation is performed, and the plaque is significantly ablated. Therefore, this invention has a good effect on the ablation of atherosclerotic tissue.

Claims

1. A mid-infrared high-power femtosecond laser atherosclerotic tissue ablation device, characterized by: The application relates to atherosclerosis ablation device and method. The chirped pulse amplification module comprises a seed source (1), a first reflector (2), a first film polarizer (3), a first half-wave plate (4), a second reflector (5), a third reflector (6), a first bichromatic mirror (7), a first-stage Yb:YAG crystal (8), a fourth reflector (9), a second half-wave plate (10), a second film polarizer (11), a second bichromatic mirror (12), a second-stage Yb:YAG crystal (13), a fifth reflector (14), a third half-wave plate (15), a third film polarizer (16), a compressor (17) and a pump source (18) which are sequentially arranged along the input direction of a signal light path; the first bichromatic mirror (7) and the second bichromatic mirror (12) are respectively connected with the output light path of the pump source (18); the seed source (1) is used for emitting 40W femtosecond laser as a seed; The mid-infrared femtosecond laser generation module comprises a white light signal generation module, a signal light parametric amplification module and an idler light parametric amplification module; the white light signal generation module is used for generating white light signals; the signal light parametric amplification module is used for receiving and amplifying the white light signals to obtain signal pulse light; the idler light parametric amplification module is used for receiving and amplifying the signal pulse light to obtain 5.75-micron mid-infrared high-power femtosecond laser with a pulse width of 280fs; The white light signal generation module comprises a sixth reflector (19), a seventh reflector (20), a fourth half-wave plate (21), a fourth film polarizer (22), a YAG crystal (23), a first long-wave pass filter (24), an eighth reflector (25) and a ninth reflector (26) which are sequentially arranged along the input direction of a signal light path; the YAG crystal (23) is used for self-phase modulation of pump light to realize spectrum broadening; The signal light parametric amplification module comprises a fifth half-wave plate (28), a fifth film polarizer (29), a tenth reflector (30), a third bichromatic mirror (27), a first LGS crystal (31), a second long-wave pass filter (32), an eleventh reflector (33) and a twelfth reflector (34) which are sequentially arranged along the input direction of a signal light path; the fourth film polarizer (22) divides the high-power femtosecond pump light into beams to the YAG crystal (23) and the fifth half-wave plate (28); the third bichromatic mirror (27) is used for receiving white light signals and combining the white light signals with the high-power femtosecond pump light; The idler light optical parametric amplification module comprises a 13th mirror (36), a 14th mirror (37), a fourth dichroic mirror (35), a second LGS crystal (38), and a germanium wafer (39) arranged in sequence along the input direction of the signal light path.

2. The mid-infrared high-power femtosecond laser atherosclerotic tissue ablation device according to claim 1, characterized in that: The fifth thin film polarizer (29) divides the high-power femtosecond pump light into the tenth mirror (30) and the 13th mirror (36); the fourth dichroic mirror (35) is used to receive the signal pulse light and combine with the high-power femtosecond pump light; the atherosclerosis ablation module comprises a 15th mirror (40), a 16th mirror (41), a zinc selenide convex lens (43), and a light-guiding ablation component arranged in sequence along the input direction of the signal light path.

3. A method of using a mid-infrared high-power femtosecond laser atherosclerotic tissue ablation device based on the mid-infrared high-power femtosecond laser atherosclerotic tissue ablation device of claim 2, characterized in that: The light-guiding ablation component is a CaF2 window sheet or an optical fiber. The method comprises the following steps: S1: Pumping the first Yb:YAG crystal (8) and the second Yb:YAG crystal (13) to the excited state by the pump source (18) of the chirped pulse amplification module; at the same time, generating 40W femtosecond laser as a seed by the seed source (1), outputting 135W laser with a wavelength of 1030nm through the first Yb:YAG crystal (8) and the second Yb:YAG crystal (13), and then outputting high-power femtosecond pump light after pulse compression by the compressor; S2: Self-phase modulation and spectral broadening of the high-power femtosecond pump light generated by the chirped pulse amplification module to obtain a white light signal with a wide spectrum by the white light signal generation module; after receiving the white light signal, the signal light optical parametric amplification module combines with the high-power femtosecond pump light, performs first-stage optical parametric amplification, filters out the high-power femtosecond pump light, and then obtains amplified signal pulse light; S3: After combining the signal pulse light with the high-power femtosecond pump light by the idler light optical parametric amplification module, performing second-stage optical parametric amplification, filtering out the high-power femtosecond pump light, and then obtaining 5.75-micron, 280-fs mid-infrared high-power femtosecond laser; 4. The method of using a mid-infrared high-power femtosecond laser atherosclerotic tissue ablation device according to claim 3, wherein: S4: Adjusting the received mid-infrared high-power femtosecond laser to different spot sizes by the zinc selenide convex lens (43), and then introducing the mid-infrared high-power femtosecond laser into the atherosclerotic tissue for ablation by the light-guiding ablation component. The method of introducing the mid-infrared high-power femtosecond laser into the atherosclerotic tissue for ablation by the light-guiding ablation component comprises introducing the mid-infrared high-power femtosecond laser into the plaque site for ablation by the CaF2 window sheet or puncturing to the lesion site, using an optical fiber attached to the inside of the puncture needle, and introducing the mid-infrared high-power femtosecond laser into the atherosclerotic tissue for ablation.

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