A scanning photoacoustic volumetric imaging apparatus with self-adaptive coupling cavity and method thereof

Abstract

The application discloses a kind of scanning photoacoustic volume imaging device and method of coupling cavity adaptive regulation, belong to photoacoustic volume imaging technical field, including coupling cavity adaptive regulation coupling device, photoacoustic volume imaging probe, photoacoustic host and display device;Coupling device includes acrylic cavity, photoacoustic window, photoacoustic soft membrane and telescopic folding cover, cylindrical ring acrylic cavity is connected with photoacoustic volume imaging probe, telescopic folding cover is connected with the lower end of acrylic cavity, water inlet is opened in the top of acrylic cavity, and oval through-hole is opened along the circumferential equidistance in the bottom of acrylic cavity, photoacoustic soft membrane is fixedly installed at the front end of photoacoustic window, and photoacoustic soft membrane is located below the detection end of photoacoustic volume imaging probe;Photoacoustic volume imaging probe is connected with photoacoustic host, and photoacoustic host is connected with display device.This application is applicable to clinical rapid screening, especially applicable to the free scanning high-resolution imaging of irregular tissue surface.

Description

Technical Field

[0001] This invention relates to the field of photoacoustic volumetric imaging technology, and more specifically to a scanning photoacoustic volumetric imaging device and method with adaptive adjustment of the coupling cavity. Background Technology

[0002] Photoacoustic tomography (PACT) combines the high contrast of optical imaging with the deep penetration of ultrasound imaging, making it a promising non-destructive testing technique in the field of biomedical imaging. This technique detects the ultrasonic signals generated when biological tissue absorbs pulsed laser light, enabling high-resolution imaging of tissue structure and function. Due to its advantages such as high resolution, deep imaging capabilities, high optical contrast, and non-destructive testing in vivo, PACT has received widespread attention and rapid development in recent years.

[0003] Photoacoustic imaging systems based on spherical arrays offer the capability to achieve three-dimensional volumetric imaging with a single excitation, significantly improving imaging efficiency. However, traditional handheld free-scanning spherical array photoacoustic imaging systems still have certain limitations in practical applications: imaging often requires immersing the sample in a coupling fluid or fixing it under a large tank filled with coupling fluid and coupling it through a soft membrane. This coupling method limits the system's free movement and multi-angle scanning capabilities in live imaging, reducing operational flexibility and applicable scenarios. Furthermore, the optimal acoustic field region of a spherical array is usually located near its center; to achieve the best imaging effect, the distance between the probe and the sample often needs to be adjusted along the axis, further increasing operational complexity.

[0004] Therefore, there is an urgent need to develop a compact, handheld integrated imaging device that can effectively integrate the coupling cavity and photoacoustic imaging probe, thereby improving the system's portability, flexibility, and ease of use while ensuring imaging quality, in order to meet the needs of photoacoustic volumetric imaging for living subjects, multiple angles, and free scanning.

[0005] Based on this, the present invention designs a scanning photoacoustic volumetric imaging device and method with adaptive adjustment of coupling cavity to solve the above problems. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a scanning photoacoustic volumetric imaging device and method with adaptive adjustment of coupling cavity.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A scanning photoacoustic volume imaging device with adaptively adjustable coupling cavity includes a coupling device with adaptively adjustable coupling cavity, a photoacoustic volume imaging probe, a photoacoustic host, and a display device.

[0009] The coupling device includes an acrylic cavity, a photoacoustic window, a photoacoustic diaphragm, and a retractable folding sleeve. The cylindrical annular acrylic cavity is connected to the photoacoustic volume imaging probe, and the retractable folding sleeve is connected to the lower end of the acrylic cavity. A water inlet is provided at the top of the acrylic cavity, and elliptical through holes are provided at equal intervals along the circumference at the bottom of the acrylic cavity. The photoacoustic diaphragm is fixedly installed at the front end of the photoacoustic window and is located below the detection end of the photoacoustic volume imaging probe.

[0010] The photoacoustic volumetric imaging probe is connected to the photoacoustic host, and the photoacoustic host is connected to the display device.

[0011] Furthermore, the acrylic cavity is made of transparent medical-grade acrylic material.

[0012] Furthermore, the diameter of the photoacoustic window is 45mm, which is more than 1.5 times the diameter of the molding area.

[0013] Furthermore, the photoacoustic membrane is made of photoacoustic PDMS membrane with a smooth surface, a thickness of less than 0.5mm, a light transmittance of over 90%, and an ultrasonic transmittance of over 85%.

[0014] Furthermore, the retractable folding sleeve is wavy, and its adjustable length ranges from 5 to 20 mm.

[0015] Furthermore, the photoacoustic volumetric imaging probe includes a three-dimensional bowl-shaped ultrasonic transducer, an optical fiber bundle, a diffusion lens, and a probe housing. The three-dimensional bowl-shaped ultrasonic transducer is fixedly installed in the cavity of the probe housing. The optical fiber bundle is fixed in the reserved internal thread channel of the probe housing by an external threaded ring. The diffusion lens is fixed to the output end of the optical fiber bundle by a threaded connection and is located between the three-dimensional bowl-shaped ultrasonic transducer and the optical fiber bundle. The optical fiber bundle is connected to the photoacoustic host.

[0016] Furthermore, the three-dimensional bowl-shaped ultrasonic transducer includes 256 ultrasonic array elements with a diameter of 2.5 mm. The three-dimensional bowl-shaped ultrasonic transducer is fixedly installed in the cavity of the probe housing in three-dimensional space according to the Fibonacci-Fermat double helix law and the requirement that each array element is equidistantly distributed on the Z-axis. The cavity is a sphere with an inner diameter Rn of 100 mm and an angle of 130°.

[0017] Furthermore, the center frequency of the three-dimensional bowl-shaped ultrasonic transducer is 5MHz.

[0018] Furthermore, the photoacoustic host includes a laser module, a control module, a data acquisition module, and a data processing module; the laser module for generating pulsed lasers is connected to the fiber optic bundle, the data acquisition module for amplifying and receiving the electrical signals of the three-dimensional bowl-shaped ultrasonic transducer is connected to the three-dimensional bowl-shaped ultrasonic transducer, and the control module is connected to the laser module, the data acquisition module, and the data processing module.

[0019] An imaging method, utilizing a scanning photoacoustic volumetric imaging device with adaptively adjustable coupling cavity, includes the following steps:

[0020] Step 1: Stretch the photoacoustic diaphragm and lay it flat on the photoacoustic window, tighten it with metal screws, and cut off the excess part of the photoacoustic diaphragm.

[0021] Step 2: Adjust the telescopic folding sleeve to its maximum deformation state, and inject coupling fluid through the water inlet until the coupling fluid fills the entire probe housing. Then reset the telescopic folding sleeve. At this time, the photoacoustic diaphragm will deform and bulge due to the liquid pressure.

[0022] Step 3: Apply the photoacoustic membrane tightly to the surface of the tissue in the imaging area;

[0023] Step 4: The control module starts up, sends a synchronization signal, triggers the laser module to generate pulsed laser, the pulsed laser is transmitted through the fiber bundle and irradiates the imaging area, exciting the tissue to generate photoacoustic signals;

[0024] Step 5: Hold the probe housing and scan freely. Based on the deformation characteristics of the scanning path and the imaging surface, the retractable folding sleeve can achieve elastic adaptive adjustment, enabling the device to complete photoacoustic volumetric imaging under different angle and depth conditions.

[0025] Step Six: The three-dimensional bowl-shaped ultrasonic transducer receives the photoacoustic signal and converts it into an electrical signal; the data acquisition module amplifies, filters, and performs analog-to-digital conversion on the electrical signal and stores it; the data processing module performs three-dimensional image reconstruction on the stored digital signal to obtain a photoacoustic volume image; the display device interactively displays the reconstructed three-dimensional photoacoustic volume image in real time.

[0026] Compared with the prior art, the beneficial effects of this invention are as follows: During the imaging process, the operator holds the photoacoustic volumetric imaging probe close to the tissue surface of the imaging area. The photoacoustic diaphragm of the coupling device contacts the tissue surface of the imaging area. The elastic, retractable, and foldable sleeve adjusts the depth of the coupling cavity as needed to adapt to different tissue surfaces and imaging depths, providing high flexibility and expanding the application scenarios of the system. The coupling fluid or deionized water is injected into the acrylic cavity through the water inlet and then filled into the retractable and foldable sleeve through the elliptical through-hole. The coupling fluid or deionized water fills the photoacoustic diaphragm and the photoacoustic volumetric imaging probe. The diaphragm deforms and expands under the liquid pressure, ensuring uniform filling with the coupling fluid or deionized water. The photoacoustic host controls the photoacoustic volumetric imaging probe to start, and the photoacoustic host and the photoacoustic volumetric imaging probe perform photoacoustic volumetric imaging. The results are then displayed on the display device, making the imaging process intuitive, efficient, and easy to operate. It is suitable for rapid clinical screening, especially for free-scanning high-resolution imaging of irregular tissue surfaces. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0028] Figure 1 This is a structural diagram of the coupling device;

[0029] Figure 2 Cross-sectional view of a scanning photoacoustic volumetric imaging device with adaptive adjustment of the coupling cavity;

[0030] Figure 3 System block diagram of a scanning photoacoustic volumetric imaging device with adaptive adjustment of the coupling cavity. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] The terms "left," "right," "front," "back," "up," and "down" used in the following description refer to the orientation from the perspective of the front view.

[0033] Example 1: In some embodiments, please refer to the accompanying drawings. Figure 1-3 A scanning photoacoustic volumetric imaging device with adaptively adjustable coupling cavity includes a coupling device with adaptively adjustable coupling cavity, a photoacoustic volumetric imaging probe, a photoacoustic host, and a display device.

[0034] The coupling device includes an acrylic cavity 1, a photoacoustic window 3, a photoacoustic diaphragm 4, and a retractable folding sleeve 5. The cylindrical annular acrylic cavity 1 is connected to the photoacoustic volume imaging probe, and the retractable folding sleeve 5 is connected to the lower end of the acrylic cavity 1. A water inlet 6 is provided at the top of the acrylic cavity 1, and elliptical through holes 2 are provided at equal intervals along the circumference at the bottom of the acrylic cavity 1. The photoacoustic diaphragm 4 is fixedly installed at the front end of the photoacoustic window 3 and is located below the detection end of the photoacoustic volume imaging probe.

[0035] The photoacoustic volumetric imaging probe is connected to the photoacoustic host, and the photoacoustic host is connected to the display device.

[0036] Water inlet 6 is connected to the liquid or deionized water supply equipment via a pipe;

[0037] During the imaging process, the operator holds the photoacoustic volumetric imaging probe close to the tissue surface of the imaging area. The photoacoustic diaphragm 4 of the coupling device contacts the tissue surface of the imaging area. The elastic, retractable, and foldable sleeve 5 adjusts the depth of the coupling cavity as needed to adapt to different tissue curvatures and imaging depths, offering high flexibility and expanding the system's application scenarios. Coupling fluid or deionized water is injected into the acrylic cavity 1 through the water inlet 6, and then filled into the retractable and foldable sleeve 5 through the elliptical through-hole 2. Coupling fluid or deionized water fills the photoacoustic diaphragm 4 and the photoacoustic volumetric imaging probe. The photoacoustic diaphragm 4 deforms and expands under liquid pressure, ensuring uniform filling with coupling fluid or deionized water. The photoacoustic host controls the photoacoustic volumetric imaging probe to start, and the photoacoustic host and the photoacoustic volumetric imaging probe perform photoacoustic volumetric imaging. The results are then displayed on the display device, making the imaging process intuitive, efficient, and easy to operate. It is suitable for rapid clinical screening, especially for high-resolution imaging of irregular tissue surfaces.

[0038] Acrylic cavity 1 is made of transparent medical-grade acrylic material;

[0039] The diameter of the photoacoustic window 3 is 45mm, which is more than 1.5 times the diameter of the molding area.

[0040] The elliptical through-hole 2 is provided with at least 12 sets;

[0041] To avoid the hardware structure blocking the propagation path of the acoustic signal, and at the same time reduce the deformation of the soft membrane caused by the liquid pressure in the coupling cavity;

[0042] The photoacoustic diaphragm 4 has a smooth surface and a thickness of less than 0.5 mm, a light transmittance of over 90%, and an ultrasonic transmittance of over 85%.

[0043] It has good light transmittance and ultrasonic penetration.

[0044] The retractable folding sleeve 5 is wavy and made of silicone rubber, allowing for multi-angle elastic stretching and adjustment in the imaging depth direction.

[0045] The adjustable length of the retractable folding sleeve 5 is 5-20mm.

[0046] When imaging deep tissues is required, the folding sleeve is compressed to a length of 5 mm; when imaging superficial tissues is required, the folding sleeve is stretched to a length of 20 mm.

[0047] Achieve high-quality imaging of regions at different depths.

[0048] The photoacoustic window 3 is provided with external threads, which can fix the photoacoustic diaphragm 4 to the front end of the photoacoustic window 3 by a matching metal screw ring.

[0049] The photoacoustic volumetric imaging probe includes a three-dimensional bowl-shaped ultrasonic transducer 7, an optical fiber bundle 8, a diffusion lens 9, and a probe housing 10. The three-dimensional bowl-shaped ultrasonic transducer 7 is fixedly installed in the cavity of the probe housing 10. The optical fiber bundle 8 is fixed in the reserved internal thread channel of the probe housing 10 by an external threaded ring. The diffusion lens 9 is fixed to the output end of the optical fiber bundle 8 by a threaded connection and is located between the three-dimensional bowl-shaped ultrasonic transducer 7 and the optical fiber bundle 8. The optical fiber bundle 8 is connected to the photoacoustic host.

[0050] The height of the acrylic cavity 1 is half the outer diameter of the probe housing 10.

[0051] The three-dimensional bowl-shaped ultrasonic transducer 7 includes 256 ultrasonic array elements with a diameter of 2.5 mm. The three-dimensional bowl-shaped ultrasonic transducer 7 is fixedly installed in the cavity of the probe housing 10 in three-dimensional space according to the Fibonacci-Fermat double helix law and the requirement that each array element is equidistantly distributed on the Z-axis. The cavity is a spherical surface with an inner diameter Rn of 100 mm and an angle of 130°.

[0052] The acrylic cavity 1 is fixedly connected to the probe housing 10 by adhesive bonding. The top of the acrylic cavity 1 is higher than the ultrasonic array element of the uppermost three-dimensional bowl-shaped ultrasonic transducer 7.

[0053] The center frequency of the three-dimensional bowl-shaped ultrasonic transducer 7 is 5MHz.

[0054] The three-dimensional bowl-shaped ultrasonic transducer 7 has a 1-inch diameter non-array threaded through hole at its center, which is used to allow the excitation light to uniformly illuminate the imaging area from directly above.

[0055] Fiber bundle with 8 cores, 200μm in diameter;

[0056] The photoacoustic host includes a laser module, a control module, a data acquisition module, and a data processing module; the laser module for generating pulsed lasers is connected to the fiber bundle 8, the data acquisition module for amplifying and receiving electrical signals from the three-dimensional bowl-shaped ultrasonic transducer 7 is connected to the three-dimensional bowl-shaped ultrasonic transducer 7, and the control module is connected to the laser module, the data acquisition module, and the data processing module.

[0057] The pulse width range of the laser module is 5-10 ns.

[0058] The control module generates a square wave control signal, which activates the laser module and the data acquisition module. The laser module generates pulsed laser light, which is transmitted through fiber bundle 8 to irradiate and excite the imaging area to generate photoacoustic signals. The data acquisition module amplifies and receives the electrical signals from the three-dimensional bowl-shaped ultrasonic transducer 7, then performs analog-to-digital conversion and stores them. The data processing module processes the stored data, performs three-dimensional image reconstruction, and real-time three-dimensional stitching.

[0059] The display device is used to interactively display the reconstructed 3D photoacoustic volumetric image in real time.

[0060] PDMS: Polydimethylsiloxane;

[0061] An imaging method, utilizing a scanning photoacoustic volumetric imaging device with adaptively adjustable coupling cavity, includes the following steps:

[0062] Step 1: Stretch the photoacoustic membrane 4 and lay it flat on the photoacoustic window 3. Tighten and fix it with metal screw rings. Cut off the excess part of the photoacoustic membrane 4.

[0063] Step 2: Adjust the retractable folding sleeve 5 to its maximum deformation state, and inject coupling fluid through the water inlet 6 until the coupling fluid fills the entire probe housing 10. Then reset the retractable folding sleeve 5. At this time, the photoacoustic diaphragm 4 will deform and bulge due to the liquid pressure.

[0064] Step 3: Apply the photoacoustic membrane 4 tightly to the surface of the tissue in the imaging area;

[0065] Step 4: The control module starts up, sends a synchronization signal, triggers the laser module to generate pulsed laser, the pulsed laser is transmitted through fiber bundle 8 and irradiates the imaging area, exciting the tissue to generate photoacoustic signals;

[0066] Step 5: Hold the probe housing 10 and perform free scanning. Based on the deformation characteristics of the scanning path and the imaging surface, the retractable folding sleeve can achieve elastic adaptive adjustment, enabling the device to complete photoacoustic volumetric imaging under different angle and depth conditions.

[0067] Step Six: The three-dimensional bowl-shaped ultrasonic transducer 7 receives the photoacoustic signal and converts it into an electrical signal; the data acquisition module amplifies, filters, and performs analog-to-digital conversion on the electrical signal and stores it; the data processing module performs three-dimensional image reconstruction on the stored digital signal to obtain a photoacoustic volume image; the display device interactively displays the reconstructed three-dimensional photoacoustic volume image in real time.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A scanning photoacoustic volumetric imaging device with adaptively adjustable coupling cavity, characterized in that: It includes a coupling device with adaptive adjustment of the coupling cavity, a photoacoustic volumetric imaging probe, a photoacoustic host, and a display device; The coupling device includes an acrylic cavity (1), a photoacoustic window (3), a photoacoustic diaphragm (4), and a retractable folding sleeve (5). The cylindrical annular acrylic cavity (1) is connected to the photoacoustic volume imaging probe. The retractable folding sleeve (5) is connected to the lower end of the acrylic cavity (1). A water inlet (6) is opened at the top of the acrylic cavity (1). Elliptical through holes (2) are opened at equal intervals along the circumference at the bottom of the acrylic cavity (1). The photoacoustic diaphragm (4) is fixedly installed at the front end of the photoacoustic window (3). The photoacoustic diaphragm (4) is located below the detection end of the photoacoustic volume imaging probe. The photoacoustic volumetric imaging probe is connected to the photoacoustic host, and the photoacoustic host is connected to the display device. The diameter of the photoacoustic window (3) is 45 mm, and the diameter of the photoacoustic window (3) is more than 1.5 times the diameter of the forming area; The retractable folding sleeve (5) is wavy, and the adjustable length range of the retractable folding sleeve (5) is 5-20mm; The photoacoustic volumetric imaging probe includes a three-dimensional bowl-shaped ultrasonic transducer (7), an optical fiber bundle (8), a diffusion lens (9), and a probe housing (10). The three-dimensional bowl-shaped ultrasonic transducer (7) is fixedly installed in the cavity of the probe housing (10). The optical fiber bundle (8) is fixed in the reserved internal thread channel of the probe housing (10) by an external threaded ring. The diffusion lens (9) is fixed to the output end of the optical fiber bundle (8) by a threaded connection. The diffusion lens (9) is located between the three-dimensional bowl-shaped ultrasonic transducer (7) and the optical fiber bundle (8). The optical fiber bundle (8) is connected to the photoacoustic host. The three-dimensional bowl-shaped ultrasonic transducer (7) includes 256 ultrasonic array elements with a diameter of 2.5 mm. The three-dimensional bowl-shaped ultrasonic transducer (7) is fixedly installed in the cavity of the probe housing (10) in three-dimensional space according to the Fibonacci-Fermat double helix law and the requirement that each array element is equidistantly distributed on the Z-axis. The cavity is a spherical surface with an inner diameter Rn of 100 mm and an angle of 130°. The center frequency of the three-dimensional bowl-shaped ultrasonic transducer (7) is 5MHz.

2. The scanning photoacoustic volumetric imaging device with adaptive coupling cavity adjustment according to claim 1, characterized in that, The acrylic cavity (1) is made of transparent medical-grade acrylic material.

3. The scanning photoacoustic volumetric imaging device with adaptive coupling cavity adjustment according to claim 1, characterized in that, The photoacoustic soft membrane (4) is a photoacoustic PDMS soft membrane with a smooth surface, a thickness of less than 0.5 mm, a light transmittance of more than 90%, and an ultrasonic transmittance of more than 85%.

4. The scanning photoacoustic volumetric imaging device with adaptive coupling cavity adjustment according to claim 3, characterized in that, The photoacoustic host includes a laser module, a control module, a data acquisition module, and a data processing module; the laser module for generating pulsed lasers is connected to the fiber bundle (8), the data acquisition module for amplifying and receiving the electrical signals of the three-dimensional bowl-shaped ultrasonic transducer (7) is connected to the three-dimensional bowl-shaped ultrasonic transducer (7), and the control module is connected to the laser module, the data acquisition module, and the data processing module.

5. An imaging method utilizing the scanning photoacoustic volumetric imaging device with adaptive coupling cavity adjustment as described in claim 4, characterized in that, Includes the following steps: Step 1: Stretch the photoacoustic membrane (4) and lay it flat on the photoacoustic window (3), tighten and fix it with metal screw rings, and cut off the excess part of the photoacoustic membrane (4). Step 2: Adjust the retractable folding sleeve (5) to the maximum deformation state, and inject coupling fluid through the water inlet (6) until the coupling fluid fills the entire probe housing (10). Reset the retractable folding sleeve (5). At this time, the photoacoustic diaphragm (4) will deform and bulge due to the liquid pressure. Step 3: Place the photoacoustic membrane (4) tightly onto the surface of the tissue in the imaging area; Step 4: The control module starts up, sends a synchronization signal, triggers the laser module to generate pulsed laser, the pulsed laser is transmitted through the fiber bundle (8) and irradiates the imaging area, exciting the tissue to generate photoacoustic signals; Step 5: Hold the probe housing (10) and perform free scanning. Based on the deformation characteristics of the scanning path and the imaging surface, the retractable folding sleeve can achieve elastic adaptive adjustment, so that the device can complete photoacoustic volume imaging under different angles and depths. Step 6: The three-dimensional bowl-shaped ultrasonic transducer (7) receives the photoacoustic signal and converts it into an electrical signal; the data acquisition module amplifies, filters and converts the electrical signal into an analog-to-digital signal and stores it; the data processing module performs three-dimensional image reconstruction on the stored digital signal to obtain a photoacoustic volume image; the display device displays the reconstructed three-dimensional photoacoustic volume image in real time.

Images