Body surface laser ablation device

Abstract

The present invention proposes a body surface laser ablation device, comprising a laser, a beam shaper and a cylinder with double-sided openings. The laser emitted by the laser is incident into the cylinder through the beam shaper, and irradiates the irradiated object along the optical path in the cylinder. The device is characterized in that a radial magnetic field is provided at the focus of the optical path. The radial magnetic field is used to deflect the tissue residue after ablation in the plasma state, which ultimately leads to stable light output power and improved reliability of the ablation device.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a body surface laser ablation device. Background Art

[0002] In the field of medical devices, there are many devices that use lasers to ablate the surface of organisms, which are used to obtain various liquids in various organisms. This type of laser equipment emits a laser beam with a wavelength of 2.94μm in a very short time, and instantly generates high temperature gasification to form a micropore on the surface tissue of the organism, and its instantaneous temperature can reach 1000°C. The tissue residue after ablation is ejected in the direction of the laser light outlet in a plasma state, adsorbed on the surface of the optical lens group, causing pollution, interfering with the subsequent laser ablation process, resulting in unstable light output power and poor reliability.

[0003] Existing equipment of this type uses disposable protective covers to alleviate the contamination problem of the optical lens group. This method will increase the cost of using the instrument and the complexity of operation. The light-transmitting membrane in the disposable protective cover will cause loss of laser emission power. The batch-to-batch difference will reduce the consistency of laser energy under other equal conditions and increase the risk of laser ablation failure. Summary of the invention

[0004] In order to solve at least one of the above technical problems, an embodiment of the present invention aims to provide a body surface laser ablation device.

[0005] In order to achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] A body surface laser ablation device comprises a laser, a beam shaper and a cylinder with double-sided openings. The laser emitted by the laser is incident into the cylinder through the beam shaper and irradiates the irradiated object along the light path in the cylinder. The device is characterized in that a radial magnetic field is provided at the focus of the light path.

[0007] The radial magnetic field is used to deflect the plasma-state ablated tissue residues, so that these ablated tissue residues will not be ejected toward the laser light outlet, and will not be adsorbed on the surface of the optical lens group to cause pollution, and will not interfere with the subsequent laser ablation process, ultimately resulting in stable light output power and improved reliability of the ablation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A half-section view of the main structure of a body surface laser ablation device provided in an embodiment of the present invention, which includes 1 a laser, 2 a beam shaper, 3 a cylinder, and 4 a radial magnetic field.

[0009] Figure 2 An isometric view of a permanent magnet of a body surface laser ablation device provided in an embodiment of the present invention.

[0010] Figure 3 A schematic diagram of the matching of the light path and the pollution isolation structure of the laser ablation device for body surface provided by the embodiment of the present invention, which includes 3 cylinders, 5 pollution isolation structures, and 6 light paths.

[0011] Figure 4 A schematic diagram of the distribution of light holes and pollution holes on the pollution isolation structure of the body surface laser ablation device provided by an embodiment of the present invention, which includes 5 pollution isolation structures, 6 light holes, and 7 pollution holes.

[0012] Figure 5 The axonometric diagram of the light hole and the pollution hole on the pollution isolation structure of the body surface laser ablation device provided by the embodiment of the present invention includes 5 pollution isolation structure, 6 light hole and 7 pollution hole.

[0013] Figure 6 A partial cross-sectional view of a cylinder partition of a body surface laser ablation device provided by an embodiment of the present invention, which includes 3 cylinder, 5 pollution isolation structure, 6 light through hole, 7 pollution through hole, and 8 partition.

[0014] Figure 7 A schematic diagram of the distribution of drainage holes on the outer wall of a cylinder of a body surface laser ablation device provided in an embodiment of the present invention, which includes 3 cylinders and 9 drainage holes.

[0015] Figure 8 A schematic diagram of a barrel body surface contact structure of a body surface laser ablation device provided in an embodiment of the present invention, which includes 2 beam shapers, 3 barrel bodies, 10 surface contact structures, and 11 holes.

[0016] The realization of the purpose, functional characteristics and excellent effects of the present invention will be further described below in conjunction with specific embodiments and drawings. DETAILED DESCRIPTION

[0017] In the field of medical devices, there are many devices that use lasers to ablate the surface of organisms, which are used to obtain various liquids in various organisms. This type of laser equipment emits a laser beam with a wavelength of 2.94μm in a very short time, and instantly generates high temperature gasification to form a micropore on the surface tissue of the organism, and its instantaneous temperature can reach 1000°C. The tissue residue after ablation is ejected in the direction of the laser light outlet in a plasma state, adsorbed on the surface of the optical lens group, causing pollution, interfering with the subsequent laser ablation process, resulting in unstable light output power and poor reliability.

[0018] Existing equipment of this type uses disposable protective covers to alleviate the contamination problem of the optical lens group. This method will increase the cost of using the instrument and the complexity of operation. The light-transmitting membrane in the disposable protective cover will cause loss of laser emission power. The batch-to-batch difference will reduce the consistency of laser energy under other equal conditions and increase the risk of laser ablation failure.

[0019] In order to solve the above problems, we proposed a body surface laser ablation device based on plasma jet deflection and turbulence technology, which makes the biological tissue residue after ablation deviate from the original jet path. Under the interference of the magnetic field, the residue no longer adheres to the light outlet, so as to solve the problem of tissue residue after blood collection contaminating various lenses.

[0020] By designing a turbulence cavity for the ejected residue, the plasma-state skin residue ejected in the reverse direction enters the cavity in one or more jets, interfering with the static gas and turbulence mechanism in the cavity, causing the axial jet flowing to the optical lens to turn and deviate from the axial center position of the optical lens, thereby achieving the purpose of preventing contamination of the light path.

[0021] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0022] like Figure 1 As shown, a body surface laser ablation device includes a laser, a beam shaper and a cylinder with double-sided openings. The laser emitted by the laser is incident into the cylinder through the beam shaper, and irradiates the irradiated object along the light path in the cylinder.

[0023] It is characterized in that

[0024] A radial magnetic field is arranged at the focus of the optical path.

[0025] Here, the beam shaper is a kind of optical lens, and the ejected ablated tissue residues are easily adsorbed on the surface of the beam shaper, causing contamination. The internal space of the double-sided opening cylinder is the spoiler cavity.

[0026] The tissue residue after ablation is in a plasma state due to the instantaneous high temperature. It is composed of positively charged ions and negatively charged electrons and is electrically neutral as a whole. The plasma residue will be deflected by the Lorentz force of the magnetic field during movement. Compared with positively charged ions, the mass of negatively charged electrons can be ignored, and the influence of the induced magnetic field on the flow field is not considered. Only the influence of the Lorentz force on the flow of the positive ion jet is considered. The Lorentz force it receives in the magnetic field satisfies the following equation:

[0027] F = V × B • q,

[0028] Where q is the charge per unit volume, and its calculation formula is:

[0029] q = Nαρe,

[0030] Among them, α is the ionization rate, that is, the ratio of charged particles to all particles, ρ is the density, e is the charge carried by a single electron, and N is the charge number carried by each ion, which is related to the properties of the plasma.

[0031] Due to the existence of the external magnetic field, the charged particles in the axial jet plasma of the tissue residues are deflected along the negative direction of the X-axis under the action of the Lorentz force, and their deflection trend is similar to the circular deflection of charged particles in a uniform magnetic field. The axial jet with a higher concentration in the lateral unit interface will deviate from the light exit hole in the laser light path, thereby reducing the contamination of the beam shaper.

[0032] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0033] It is characterized in that

[0034] The cylinder is a permanent magnet of radial magnetic field, or an external radial magnetic field is set outside the cylinder at the focus of the optical path. The plasma is composed of a large number of positive and negative ions and electrons. The movement of charged particles under the action of the magnetic field will inevitably cause changes in the plasma density distribution, shape and position in the laser transmission channel.

[0035] like Figure 2 As shown, when the cylinder itself is an annular permanent magnet with a radial magnetic field, the entire device is simpler than a device with an external radial magnetic field, and the cost is also reduced.

[0036] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0037] It is characterized in that

[0038] The magnetic field strength of the radial magnetic field must be greater than 0.1T.

[0039] Through our actual experiments and simulations, we found that when the magnetic field strength and other magnetic field parameters meet the requirements, 99.3% of the ejected ablated tissue residues will not be directed toward the axial center of the optical lens, thus achieving the purpose of preventing contamination of the optical path.

[0040] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0041] It is characterized in that

[0042] The middle part of the cylinder is provided with one or more dirt-isolating structures, and each dirt-isolating structure is provided with a light-passing hole.

[0043] like Figure 3As shown, the pollution isolation structure is a single-layer plane or a multi-layer plane structure, each layer includes a light exit hole. The pollution isolation structure is made of a polymer material, or a polymer coating is coated on its surface.

[0044] The aperture is designed as a through hole to avoid the loss of laser energy and prevent the loss of laser energy from vaporizing the material of the pollution isolation structure and causing additional residues (non-skin tissue residues). The size of the aperture matches the cross-sectional area of ​​the optical path of the aperture treatment.

[0045] After turbulent interference and electromagnetic interference, the axial high-density jet of the tissue residue deviates from the light path, and most of it is blocked by the pollution isolation structure and adsorbed on the polymer material of the pollution isolation structure. Only a small amount of residue passes through the light hole into the inner cavity of the tube between the beam shaper and the pollution isolation structure, reducing the contamination of the beam shaper by the tissue residue.

[0046] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0047] It is characterized in that

[0048] In addition to one light-passing hole, the dirt-isolating structure also has one or more dirt-passing holes.

[0049] like Figure 4 , Figure 5 As shown, the direction of the axial high-density jet ejected after ablation is biased towards the dirt hole, thereby guiding most of the jet not to stay in the cavity between the dirt isolation structure and the plane where the focus is located, and further guiding most of the jet not to adhere to the beam shaper.

[0050] The cavity between the pollution isolation structure and the beam shaper is a hollow device, which forms a closed space with the beam shaper. The cavity is made of polymer material, or a polymer material coating is sprayed on its surface.

[0051] After the tissue residue passes through the cavity interference and the pollution isolation structure between the pollution isolation structure and the plane where the focus is located, the remaining part passes through the light hole and the pollution hole and enters the cavity between the pollution isolation structure and the beam shaper. The design of the size and shape of the pollution hole refers to the discrete phase equation of the residual particle trajectory model, as shown below:

[0052] du p / dt = F D (u -u p ) + g(ρ p -ρ) / ρ p + F.

[0053] where u p is the particle velocity, F Dis the phase drag coefficient, F D (u -u p ) is the drag force, ρ p is the solid phase density, ρ is the gas phase density; F is the additional force phase; u is the gas phase velocity.

[0054] Because the cavity between the pollution-isolating structure and the beam shaper is closed, the jet swirls after entering the cavity, and the airflow direction at the entrance does not point directly to the beam shaper. In addition, the airflow velocity in the cavity between the pollution-isolating structure and the beam shaper is low, which can slow down the movement of tissue residues after entering the cavity. The two jets that enter the cavity through the light hole and the pollution hole collide with each other and turn in the cavity, thereby avoiding the jets from directly impacting the beam shaper, solving the problem of protecting the beam shaper from contamination. Through simulation analysis and experiments on the movement state of tissue residues with different particle diameters, it was found that the total contamination ratio of the beam shaper decreased by 93.3%.

[0055] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0056] It is characterized in that

[0057] A partition is arranged in the cylinder, which can further prevent the axial high-density jet ejected after ablation from adhering to the beam shaper.

[0058] like Figure 6 As shown, the partition plate can be used together with the pollution isolation structure to divide the interior of the cylinder into four cavities, namely, upper left, upper right, lower left and lower right. The upper left and lower left cavities contain the light-passing holes in the pollution isolation structure, and the upper right and lower right cavities contain the pollution-passing holes in the pollution isolation structure. This ensures that the incident light beam is basically separated from the axial high-density jet ejected after ablation, and ultimately results in that most of the jet will not adhere to the beam shaper.

[0059] The length of the partition between the lower left and lower right cavities is shorter than the distance between the pollution isolation structure and the plane where the focus is located, so as not to affect the incidence of the laser beam and avoid laser energy loss.

[0060] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0061] It is characterized in that

[0062] The outer wall of the cylinder has one or more drainage holes.

[0063] like Figure 7As shown, in particular, there is one or more drainage holes on the outer wall of the cylinder corresponding to the upper right and lower right cavities, which can further guide part of the jet passing through the drainage holes to be discharged into the cavity of the cylinder with double-sided openings, thereby ensuring that most of the jet will not adhere to the beam shaper.

[0064] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0065] It is characterized in that

[0066] A flow guiding device (such as a suction fan) is arranged outside the cylinder outside the sewage discharge hole to further enhance the guiding effect on the jet, thereby ensuring that most of the jet will not adhere to the beam shaper.

[0067] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0068] It is characterized in that

[0069] The end of the cylinder away from the beam shaper has a body surface contact structure, and the body surface contact structure is provided with a hole, and the diameter of the hole is less than 1 cm.

[0070] This type of equipment that uses lasers to ablate the surface of biological bodies often has a smaller laser hole and a larger barrel diameter. For example, when collecting body fluids on the surface of the human body, the human skin will have a certain curvature, resulting in inaccurate focusing of the optical path and poor light energy focusing performance, making it impossible to complete the required ablation function; or the ablation area is too large and the ablation material is too much, which leads to excessive mass of the axial high-density jet ejected after ablation, which will also affect the increase in contamination on the surface of the optical lens group, thereby interfering with the subsequent laser ablation process, and ultimately causing the light output power of the ablation device to be unstable and the reliability to be reduced. For this reason, we impose constraints at the contact point on the body surface.

[0071] like Figure 8 As shown, since the holes of the body surface contact structure are smaller, the curvature of the body surface is reduced, the focusing performance is improved, and the mass of the axial high-density jet ejected after ablation is reduced, thereby reducing the amount of contamination on the surface of the optical lens group.

[0072] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0073] It is characterized in that

[0074] The beam shaper is a long focal depth diffractive optical element.

[0075] Although the body surface contact structure reduces the curvature of the body surface, the body surface is still not completely straight in many scenarios. When the ablation device is working, it is necessary to ablate biological tissue at a certain depth. At this time, the optical system often cannot directly move the focus of its light path, which affects its ablation effect.

[0076] The beam shaper is a diffractive optical element with a long focal depth. In the scenario of this type of medical device, it is necessary to ensure that the focal depth range of the optical path of the body surface laser ablation device is greater than 3mm.

[0077] Long focal depth diffractive optical elements are a new solution that can achieve longer focal depth and higher lateral resolution (smaller spot size). Long focal depth requires a small numerical aperture, and a small spot size requires a large numerical aperture. These two are originally conflicting, but long focal depth diffractive optical elements can enable lasers to have both characteristics at the same time, so they are very suitable for some industrial applications. For example, laser drilling, cutting of transparent materials (glass, sapphire, etc.), thick steel plate laser cutting, etc.

[0078] Conventional optical elements (such as spherical lenses, mirrors, etc.) cannot meet these two characteristics at the same time. However, long focal depth diffractive optical elements can produce a long focal depth focus similar to a "long cylinder", with sharp edges and longer focal depth, while keeping the laser spot size very small.

[0079] The function of the long focal depth diffractive optical element is to make the incident laser produce a focus with nearly uniform energy distribution and focal depth of tens of microns to several millimeters near the focal length. Compared with the ordinary laser focus (the energy is very concentrated, the length and width are limited), the long focal depth diffractive optical element can stretch the laser focus to dozens to hundreds of times the original, while the width remains basically unchanged. The long focal depth spot with uniform energy is particularly suitable for deep cutting of materials.

[0080] Furthermore, the cross-sectional shape of the holes on the body surface contact structure matches the shape of the light waist, which will not affect the incidence of the laser beam and avoid laser energy loss.

[0081] Furthermore, as a specific embodiment of a body surface laser ablation device provided by the present invention, the body surface laser ablation device,

[0082] It is characterized in that

[0083] The beam shaper has a positive optical power and a clear aperture of less than 10 mm, so that the spot radius at the light waist of the body surface laser ablation device is less than 0.7 mm.

[0084] The above optical parameters are more suitable for scenarios of medical devices such as body surface laser ablation equipment, and have better ablation effects.

[0085] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A body surface laser ablation device, comprising a laser, a beam shaper and a cylinder with double-sided openings, wherein the laser emitted by the laser is incident into the cylinder through the beam shaper, and irradiates the irradiated object along the light path in the cylinder, characterized in that: A radial magnetic field is arranged at the focus of the optical path. The middle of the cylinder has one or more pollution isolation structures. Each pollution isolation structure has a light passing hole. In addition to one light passing hole, the pollution isolation structure has one or more pollution passing holes.

2. A body surface laser ablation device as claimed in claim 1, characterized in that: The cylinder is an annular permanent magnet with a radial magnetic field, or an external radial magnetic field is arranged outside the cylinder at the focus of the optical path.

3. A body surface laser ablation device as claimed in claim 2, characterized in that: The magnetic field strength of the radial magnetic field must be greater than 0.1T.

4. A body surface laser ablation device as claimed in claim 1, characterized in that: A partition is arranged in the cylinder.

5. A body surface laser ablation device as claimed in claim 4, characterized in that: The outer wall of the cylinder has one or more drainage holes.

6. A body surface laser ablation device as claimed in claim 1, characterized in that: The end of the cylinder away from the beam shaper has a body surface contact structure, and the body surface contact structure is provided with a hole, and the diameter of the hole is less than 1 cm.

7. A body surface laser ablation device as claimed in claim 1, characterized in that: The beam shaper is a long focal depth diffractive optical element.

8. A body surface laser ablation device as claimed in claim 7, characterized in that: The beam shaper has a positive optical power and a clear aperture of less than 10 mm, so that the spot radius at the light waist of the body surface laser ablation device is less than 0.7 mm.

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