Photoacoustic emission device

Abstract

The invention relates to the technical field of photoacoustic, in particular to a photoacoustic emission device, which comprises a light guide component, one end of the light guide component is connected with an emission end of a pulse or modulated laser light source so as to guide pulse or modulated laser to the other end of the light guide component; the photoacoustic conversion and ultrasonic emitting component is arranged at the preset position of the other end of the light guide component, a preset shape cavity is formed in the direction perpendicular to the central axis of the light guide component, and the cavity is filled with a light absorption medium and a thermal expansion material so as to absorb the pulse transmitted by the light guide component or modulate the laser to generate ultrasonic waves. Therefore, the problems that an existing opto-acoustic transducer cannot accurately act on a specific area, the spatial resolution is limited, the energy conversion efficiency is low, and the ultrasonic action direction is limited are solved, and the opto-acoustic transducer can be successfully applied to the fields of orientation and high-spatial-resolution regulation in ultrasonic cranial nerve regulation, needle point tracking in a puncture needle tracking scene and the like.

Description

Technical Field

[0001] This invention relates to the field of photoacoustic technology, and in particular to a photoacoustic emitting device. Background Technology

[0002] Ultrasound technology, as an advanced technology that utilizes high-frequency sound waves for detection and processing, has demonstrated broad application potential in numerous fields due to its strong penetration, good directionality, and safety (non-invasive nature). In the medical field, the application of ultrasound technology is particularly noteworthy. It extends beyond the well-known ultrasound examination (B-scan), penetrating into more refined and complex medical procedures, such as intraoperative navigation and brain nerve modulation.

[0003] However, conventional piezoelectric ultrasonic transducers typically require acoustic lens assemblies to achieve effective convergence of the ultrasonic beam. However, acoustic lenses inevitably generate energy loss during physical beam manipulation, and their structural characteristics significantly limit the miniaturization of the device. On the other hand, multi-array ultrasonic transducers can achieve dynamic focusing by adjusting the emission delay between each array element; however, this approach requires a complex multi-channel control mechanism, leading to a significant increase in system cost and control complexity. In contrast, photoacoustic transducers exhibit significant advantages in detection accuracy, anti-interference capability, and cost control. Their basic principle is that when a pulsed or modulated beam of light irradiates a light-absorbing medium, the light is absorbed and converted into heat energy, causing a local temperature increase, which in turn causes a rapid change in the medium's density, generating ultrasonic waves.

[0004] Despite the immense potential of photoacoustic transducers, their clinical application currently faces three core challenges: First, the ultrasonic fields generated by photoacoustic transducers exhibit typical three-dimensional spherical divergence, resulting in insufficient spatial wavefront modulation capabilities. This makes it difficult to achieve subwavelength-scale spatial selective acoustic field focusing in scenarios requiring millimeter-level precision, such as neuromodulation. Second, traditional forward-emitting architectures are constrained by the physical limitations of the photoacoustic conversion interface, failing to meet the lateral directional beamforming requirements in interventional diagnostic and therapeutic scenarios (such as deep brain ultrasound stimulation and acoustic navigation of puncture needles). Finally, due to the combined effects of photothermal relaxation mechanisms and acoustic impedance matching characteristics, the photoacoustic conversion efficiency of existing devices is generally low. Achieving effective tissue penetration often necessitates the use of high-energy pulsed laser systems, leading to significant challenges in device integration and safety.

[0005] Therefore, there is an urgent need to develop a new type of photoacoustic transducer to solve the three core problems of existing technologies: excessive dispersion of the sound field in space, limited direction of ultrasonic action, and low conversion efficiency. Summary of the Invention

[0006] This invention provides a photoacoustic emitting device to solve the problems of existing photoacoustic transducers, such as difficulty in accurately targeting specific areas, limited spatial resolution, low energy conversion efficiency, and limited ultrasonic direction.

[0007] A first aspect of the present invention provides a photoacoustic emitting device, comprising: a light guide component, one end of which is connected to the emitting end of a pulsed or modulated laser source to guide the pulsed or modulated laser to the other end of the light guide component; and a photoacoustic conversion and ultrasonic emission component, which is disposed at a predetermined position at the other end of the light guide component and has a predetermined shaped cavity in a direction perpendicular to the central axis of the light guide component, the cavity being filled with a light-absorbing medium and a thermally expanding material to absorb the pulsed or modulated laser transmitted by the light guide component to generate ultrasonic waves.

[0008] Optionally, the light guiding component is made of at least one of quartz optical fiber, plastic optical fiber, PDMS optical fiber, and PMMA optical fiber.

[0009] Optionally, the preset shaped cavity is any one of an inverted triangular cone, an inverted triangular pyramid, an inverted parabola, a sphere, and an ellipsoid that can apply ultrasound to a specified direction and area, and its central axis is perpendicular to the central axis of the light guide component.

[0010] Optionally, the light-absorbing medium is at least one of carbon nanotubes, graphene, carbon dots, candle ash particles, gold nanoparticles, iron oxide nanoparticles, and polypyrrole nanoparticles, and the thermal expansion material is at least one of a mixed solution of polydimethylsiloxane and isopropanol and soft biomaterials.

[0011] Optionally, it further includes: a light-reflecting medium, which is applied to the top of the other end of the light guide component to reflect any remaining laser light that is not completely absorbed by the light-absorbing medium at the other end of the light guide component, so that it can be absorbed again by the light-absorbing medium.

[0012] A second aspect of the present invention provides a puncture needle, comprising: a needle tip, the needle tip being hollow inside; a photoacoustic emitting device, the photoacoustic emitting device being disposed on one side of the hollow portion of the needle tip, and the preset shaped cavity of the photoacoustic emitting device being aligned with the shaped opening direction of the needle tip, and the front portion of the photoacoustic emitting device being coated with a light-reflecting medium.

[0013] A third aspect of the present invention provides an implantable deep brain ultrasound stimulation device, comprising: a photoacoustic emitting device, one end of which is connected to the pulsed laser, and the other end of which is implanted into a target brain tissue to modulate the target brain tissue by means of ultrasound waves generated by the photoacoustic emitting device.

[0014] The photoacoustic emitting device proposed in this invention uses a pulsed laser processing device to process a cavity structure with a special design shape and size on the end face of the light guide component. Combined with the synergistic effect of the light-absorbing medium injected into the cavity or the light-reflecting coating at the top, three key improvements can be achieved during pulsed / modulated light excitation: 1) The interface between the specially designed cavity and the thermally expanding material effectively constrains the range of ultrasonic waves. Traditional forward-emitting photoacoustic transducers suffer from easy scattering of sound waves and low resolution. This invention can concentrate the range of ultrasonic waves in a specific area, significantly improving the spatial resolution of the sound field. 2) Through the design of the lateral opening, it is able to perform lateral ultrasound modulation / probing tasks in interventional treatment scenarios and deep brain neural modulation scenarios; 3) The light-reflecting coating is used to reflect the laser light that is not completely absorbed, so that it can be absorbed again by the light-absorbing medium, which improves the light utilization efficiency and reduces the required laser power while maintaining the same sound pressure output. The above design effectively solves the problems of acoustic energy spatial dispersion, limited application space, and low light energy utilization in traditional forward-emitting architectures. While maintaining the miniaturization of the device, it can meet the core requirements of directional ultrasound emission for clinical applications such as puncture needle integration (space-constrained scenarios) and deep brain region stimulation (precise energy delivery).

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of a photoacoustic emitting device according to an embodiment of the present invention, wherein (a) is an inverted triangular pyramid, and (b) is an inverted triangular cone, an inverted parabola, a sphere, or an ellipsoid. Figure 2 This is a schematic diagram of the operation of a photoacoustic emitting device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of another photoacoustic emitting device provided according to an embodiment of the present invention; Figure 4 This is a transient analysis ultrasonic simulation diagram of a photoacoustic emitting device provided according to an embodiment of the present invention; Figure 5 This is a flowchart illustrating the fabrication method of the photoacoustic emitting device according to an embodiment of the present invention; Figure 6This is a schematic diagram of a puncture needle according to an embodiment of the present invention, wherein (a) is a side view, (b) is a front view, (c) is a perspective view, and (d) is a sectional view; Figure 7 This is a schematic diagram illustrating the working principle of a puncture needle applied to a puncture / minimally invasive surgical device according to an embodiment of the present invention. Figure 8 This is a flowchart illustrating the application of a puncture needle in a puncture / minimally invasive surgical device according to an embodiment of the present invention. Figure 9 This is a schematic diagram of an implantable deep brain ultrasound stimulation device according to an embodiment of the present invention; Figure 10 This is a flowchart illustrating the execution of an implantable deep brain ultrasound stimulation device according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 100-Photoacoustic emitting device, 101-Light guiding component, 102-Light emitting part, 103-Light reflecting medium, 104-Light absorbing medium and thermal expansion material, 200-Punch needle, 201-Needle tip diameter, 300-Cranial ultrasound stimulation device and 301-Pulse laser. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] The photoacoustic emitting device according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of a photoacoustic emitting device provided according to an embodiment of the present invention.

[0021] like Figure 1 As shown, the photoacoustic emitting device 100 includes: a light guiding component 101 and a photoacoustic conversion and ultrasonic emission component 102.

[0022] One end of the light guide component 101 is connected to the emitting end of a pulsed or modulated laser source to guide the pulsed or modulated laser to the other end of the light guide component 101. The photoacoustic conversion and ultrasonic emission component 102 is located at a preset position at the other end of the light guide component 101, and has a preset shaped cavity in a direction perpendicular to the central axis of the light guide component 101. The cavity is filled with a light-absorbing medium and a thermally expanding material 104 to absorb the pulsed or modulated laser in the optical path of the light guide component 101 to generate photoacoustic waves. The preset shaped cavity is any one of an inverted triangular cone, an inverted triangular pyramid, an inverted parabola, a sphere, and an ellipsoid that can act on the ultrasound in a specified direction and area, and its central axis is perpendicular to the central axis of the light guide component.

[0023] In some embodiments, the light guide component 101 is connected to the emitting end of a pulsed or modulated laser source using an optical fiber shaping device that employs at least one of silica optical fiber, plastic optical fiber, PDMS optical fiber, or PMMA optical fiber. That is, optical fiber technology is used to guide the pulsed or modulated laser from one end of the optical fiber shaping device to the vicinity of the opening at the other end of the optical fiber shaping device.

[0024] In some embodiments, when the light guide component 101 uses quartz optical fiber, the quartz optical fiber is an optical fiber with a core of pure quartz glass material with a high refractive index and a sheath of organic or inorganic material with a low refractive index, which gives the quartz optical fiber the characteristics of high acoustic impedance and excellent acoustic reflection capability. When one end of the quartz optical fiber is connected to the emitting end of a pulsed or modulated laser source, the pulsed or modulated laser source can be guided as far as possible from one end of the quartz optical fiber to the vicinity of the hole at the other end of the quartz optical fiber.

[0025] In some embodiments, such as Figure 2 As shown, when the preset shape of the photoacoustic conversion and ultrasonic emission component 102 is an inverted triangular cone hole, the inverted triangular cone hole is located in the optical path, perpendicular to and penetrating the preset position at the other end of the light guide component 101. The preset position is generally close to the other end of the light guide component 101, that is, the inverted triangular cone hole and the emitting end of the pulsed or modulated laser light source are respectively set at both ends of the light guide component 101.

[0026] Furthermore, the inverted triangular cone hole is filled with a light-absorbing medium and a thermal expansion material 104. Since the light-absorbing medium and the thermal expansion material 104 are directly placed in the optical path of the light guide component 101, they can effectively absorb a large number of photons of pulsed or modulated lasers in the optical path, thereby causing local transient heating and volume expansion, generating corresponding photoacoustic waves, and emitting them directionally from the inverted triangular cone hole.

[0027] The light-absorbing medium 104 can be formed by mixing at least one of carbon nanotubes, graphene, carbon dots, candle ash particles, gold nanoparticles, iron oxide nanoparticles and polypyrrole nanoparticles, and the thermal expansion material 104 can be at least one of polydimethylsiloxane and isopropanol mixture, soft biomaterials and a small amount of organic solvent.

[0028] In some embodiments, such as Figure 3 As shown, it also includes: a light-reflecting medium 103, which can be silver or other reflective materials. It is coated on the top of the other end of the light guide component 101 and close to the photoacoustic conversion and ultrasonic emission component 102 to reflect the laser light that is not completely absorbed at the other end of the light guide component 101 and converge it to the photoacoustic conversion and ultrasonic emission component 102 so that it can be absorbed again by the light-absorbing medium. This can improve the utilization rate of photons and prevent the light emitted from the other end of the light guide component 101 from damaging the target tissue.

[0029] In some embodiments of the present invention, the operation of the photoacoustic emitting device 100 is as follows: A pulsed or modulated laser emitted from a pulsed or modulated laser source is guided to the other end of a light guide component 101. A photoacoustic conversion and ultrasonic emission component 102, filled with a light-absorbing medium and a thermally expanding material 104 and positioned at a predetermined location at the other end of the light guide component 101, absorbs the pulsed or modulated laser in the optical path of the light guide component 101, causing a local transient temperature rise and resulting in volume expansion, thereby generating photoacoustic waves, which are then directionally emitted from the photoacoustic conversion and ultrasonic emission component 102. Furthermore, this embodiment of the invention also performs transient analysis and ultrasonic simulation of the photoacoustic emission device, such as... Figure 4 As shown, it can be observed that it has a strong directionality.

[0030] In addition, a light-reflecting medium 103 can be coated on the other end of the light guide component 101 to reflect the pulsed or modulated laser at the other end of the light guide component 101, so as to converge it into the photoacoustic conversion and ultrasonic emission component 102, thereby improving the utilization rate of photons.

[0031] It should be noted that, as Figure 5 As shown, the photoacoustic emitting device proposed in this embodiment of the invention generally uses a femtosecond laser to etch a hole with a preset shape cavity on the side of an optical fiber, injects a pre-configured light absorption medium that meets the requirements into the hole etched with the preset shape cavity on the side of the optical fiber, and then heats and cures it or places it in a constant temperature and pressure environment for a long time to obtain the photoacoustic emitting device.

[0032] The following is in conjunction with the appendix Figure 6-10 This invention provides a detailed description of some applications of the photoacoustic emitting device proposed in the embodiments of the present invention.

[0033] like Figure 6 As shown, the photoacoustic emitting device proposed in this embodiment of the invention is applied to a puncture needle. Specifically, the puncture needle 200 based on the photoacoustic emitting device includes: a hollow needle tip 201 and a photoacoustic emitting device 100. The photoacoustic emitting device 100 is placed on one side of the hollow length of the needle tip 201, and the preset shape cavity of the photoacoustic emitting device 100 is consistent with the opening direction of the needle tip 201. The front part of the photoacoustic emitting device is coated with a light-reflecting medium.

[0034] like Figure 7 and 8 As shown in the embodiments of the present invention, the puncture needle can be used for intraoperative navigation and positioning during puncture. After the doctor determines the surgical or puncture target, the puncture needle is inserted into the target tissue, and a pulsed laser is emitted to the photoacoustic emitting device in the puncture needle, thereby emitting photoacoustic waves to the target tissue. In addition, an ultrasonic emission control circuit can be used to synchronously emit ultrasonic waves to the target tissue with the puncture needle. Finally, the ultrasonic transducer array receives and converts the ultrasonic waves and photoacoustic waves to obtain the corresponding electrical signals. The electrical signals are then converted from analog to digital signals, and the digital signals are used to reconstruct the image to obtain the current ultrasound image after the needle has been inserted into the target tissue. After obtaining the current ultrasound image, the doctor can use the current ultrasound image as a navigation tool to move the puncture needle and continuously acquire new ultrasound images during the movement until the target position is reached.

[0035] like Figure 9 and 10 As shown, the photoacoustic emitting device proposed in this embodiment of the invention is applied to an implantable deep brain ultrasound stimulation device 300. This implantable deep brain ultrasound stimulation device 300 may include a pulsed laser 301 and a photoacoustic emitting device 100. The pulsed laser 301 emits a low-power, fast-pulsed laser source, and the energy and frequency of the pulsed laser source are adjustable. One end of the photoacoustic emitting device 100 is connected to the pulsed laser, and the other end is implanted into the target brain tissue. Because the ultrasound emission direction of the photoacoustic emitting device 100 is fixed, after the pulsed or modulated laser emitted by the pulsed laser 301, the light absorption medium 104 of the photoacoustic emitting device 100 absorbs a stronger wavelength to obtain the optimal photoacoustic wave, which can then directionally activate the target brain region. That is, the optimal photoacoustic wave is used to activate the target brain tissue, thereby affecting the relevant behavior of the experimental subject (such as a mouse). When this implantable deep brain ultrasound stimulation device 300 is applied to brain nerve stimulation scenarios, it can accurately locate and activate brain regions without the need for transgenic or viral transfection.

[0036] In summary, the photoacoustic emitting device proposed in this embodiment of the invention, by using an optical fiber shaping device to drill a hole of a specific size at one end of the optical fiber shaping device, enables the photoacoustic signal to be emitted in a predetermined direction and with a specific acoustic beam. Injecting a light-absorbing medium into the hole allows photoacoustic waves to be excited when pulsed or modulated light irradiates the light-absorbing medium, achieving efficient energy conversion. This significantly reduces the energy requirements of the laser, lowers the overall system cost, and enables directional emission through the hole, achieving precise control of the ultrasound action area. This solves the problem that current photoacoustic transducers struggle to achieve directional photoacoustic wave emission while maintaining signal strength and a small size. It can be applied to multiple fields such as medical imaging, puncture / intraoperative guidance, and intracranial ultrasound stimulation, demonstrating significant practicality and flexibility.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A photoacoustic emission device, characterized by, The application relates to a photoacoustic emission device, comprising: a light guide component, one end of which is connected with an emission end of a pulse or modulated laser light source to guide the pulse or modulated laser light to the other end of the light guide component; a photoacoustic conversion and ultrasonic emission component, which is arranged at a preset position of the other end of the light guide component and is provided with a preset shape cavity in a vertical direction of a central axis of the light guide component, and the cavity is filled with a light absorption medium and a thermal expansion material to absorb the pulse or modulated laser light transmitted by the light guide component to generate ultrasonic waves.

2. The photoacoustic emission device of claim 1, wherein, The light guide component is at least one of a quartz optical fiber, a plastic optical fiber, a PDMS optical fiber and a PMMA optical fiber.

3. The photoacoustic emission apparatus according to claim 1, characterized by, The preset shape cavity is any one of an inverted triangular cone, an inverted triangular pyramid, an inverted paraboloid, a spherical surface and an ellipsoidal surface, which can apply ultrasonic waves to a specified direction and region, and the central axis direction is perpendicular to the central axis of the light guide component.

4. The photoacoustic emission apparatus according to claim 3, characterized by The light absorption medium is at least one of carbon nanotubes, graphene, carbon dots, candle soot particles, gold nanoparticles, iron oxide nanoparticles and polypyrrole nanoparticles, and the thermal expansion material is at least one of a polydimethylsiloxane and isopropyl alcohol mixed solution and a soft biological metamaterial.

5. The photoacoustic emission apparatus according to claim 1, characterized by The application further comprises: a light reflection medium, which is applied to the top end of the other end of the light guide component to reflect the remaining laser light which is not completely absorbed by the light absorption medium at the other end of the light guide component, so as to be reabsorbed by the light absorption medium.

6. A puncture needle characterized by, The application relates to a photoacoustic emission device, comprising: a needle tip, which is hollow inside; a photoacoustic emission device, which is arranged on one side of the hollow part of the needle tip, the preset shape cavity of the photoacoustic emission device is consistent with the opening direction of the shape of the needle tip, and the front part of the photoacoustic emission device is coated with a light reflection medium.

7. An implantable deep brain ultrasound stimulation device, characterized in that, The application relates to a photoacoustic emission device, comprising: a photoacoustic emission device, one end of which is connected with the pulse laser, and the other end of which is implanted into target brain tissue to regulate the target brain tissue through ultrasonic waves generated by the photoacoustic emission device.

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