Photoacoustic imaging method and photoacoustic imaging system

Abstract

The invention discloses a photoacoustic imaging method and a photoacoustic imaging system, and the method comprises the steps: transmitting laser to an imaging target, and receiving a photoacoustic signal returned by the imaging target; determining the light intensity of the laser, and determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser; obtaining a luminous flux distribution result corresponding to the absorption coefficient of the skin layer, wherein the luminous flux distribution result is used for representing luminous flux distribution conditions of the biological tissue under different imaging depths; acquiring photoacoustic image data of the imaging target; compensating the photoacoustic image data based on the luminous flux distribution result to obtain compensated photoacoustic image data; and generating a photoacoustic image according to the compensated photoacoustic image data. The photoacoustic data is compensated according to the luminous flux distribution result corresponding to the absorption coefficient of the skin layer, and the quality and precision of the photoacoustic image can be improved.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic imaging technology, and more particularly to a photoacoustic imaging method and a photoacoustic imaging system. Background Art

[0002] During the propagation of light in the human body, behaviors such as scattering and absorption occur, which result in non-uniform light field flux in the human body. Different substances have different optical properties at different wavelengths. The mechanism of the photoacoustic effect mainly relies on the light absorption ability of substances to generate photoacoustic signals. The photoacoustic imaging technology relies on the differences in absorption coefficients between different substances to generate signals of different intensities, thereby identifying biological information. To ensure the accuracy of photoacoustic imaging, it is necessary to clarify the distribution of light flux in the imaging area.

[0003] By obtaining the light flux distribution in the imaging area for light flux correction, the accuracy of photoacoustic imaging can be improved, and the precision of photoacoustic quantitative analysis can be increased. However, in actual clinical applications, there may be significant differences in light flux distribution among different patients or different parts, and a single invariant model may not meet clinical needs. Summary of the Invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description section. The Summary of the Invention section of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0005] An embodiment of the present invention provides a photoacoustic imaging method, the method comprising:

[0006] Emitting a laser to an imaging target and receiving the photoacoustic signal returned by the imaging target;

[0007] Determining the light intensity of the laser, and determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser;

[0008] Obtaining a light flux distribution result corresponding to the absorption coefficient of the skin layer, the light flux distribution result being used to characterize the light flux distribution of biological tissues at different imaging depths;

[0009] Obtaining the photoacoustic image data of the imaging target;

[0010] Compensating the photoacoustic image data based on the light flux distribution result to obtain compensated photoacoustic image data;

[0011] Generating a photoacoustic image according to the compensated photoacoustic image data.

[0012] In one embodiment, determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser includes:

[0013] determining an initial acoustic pressure generated by the skin layer absorbing light energy according to the photoacoustic signal;

[0014] determining the light flux of the skin layer according to the light intensity of the laser;

[0015] An absorption coefficient of the skin layer is determined according to the initial sound pressure and the light flux, wherein the absorption coefficient is proportional to the initial sound pressure and inversely proportional to the light flux.

[0016] In one embodiment, determining the intensity of the laser light includes:

[0017] The light intensity of the laser light is measured by an optical sensor.

[0018] In one embodiment, the method further comprises:

[0019] The thickness and / or shape of the skin layer is determined, and the light flux distribution result also corresponds to the thickness and / or shape of the skin layer.

[0020] In one embodiment, determining the thickness and / or shape of the skin layer comprises:

[0021] displaying an ultrasound image of the imaging target, and displaying a first marker arranged along a boundary of the skin layer in the ultrasound image;

[0022] An adjustment operation on the first identifier is received, and the thickness and / or shape of the skin layer is determined according to the adjusted first identifier.

[0023] In one embodiment, determining the thickness of the skin layer comprises:

[0024] displaying an ultrasonic image of the imaging target, and displaying a second marker arranged along a thickness direction of the skin layer in the ultrasonic image;

[0025] An adjustment operation on the second identifier is received, and the thickness of the skin layer is determined according to the adjusted second identifier.

[0026] In one embodiment, the method further comprises: superimposing and displaying the photoacoustic image of the imaging target before correction on the ultrasound image.

[0027] In one embodiment, obtaining a light flux distribution result corresponding to the absorption coefficient of the skin layer includes:

[0028] Get the preset luminous flux distribution result;

[0029] Modify the preset light flux distribution result according to the absorption coefficient of the skin layer to obtain a light flux distribution result corresponding to the absorption coefficient of the skin layer.

[0030] In one embodiment, the obtaining of the light flux distribution result corresponding to the absorption coefficient of the skin layer includes:

[0031] Among a plurality of pre-stored light flux distribution results, select the light flux distribution result corresponding to the absorption coefficient of the skin layer, where the plurality of light flux distribution results are obtained by pre-simulating and imaging different simulation target tissues corresponding to different absorption coefficients;

[0032] Alternatively, perform real-time simulation and imaging on the simulation target tissue corresponding to the absorption coefficient of the skin layer to obtain a light flux distribution result corresponding to the absorption coefficient of the skin layer.

[0033] In one embodiment, the light flux distribution result also corresponds to the type of biological tissue of the imaging target.

[0034] In one embodiment, the light flux distribution result also corresponds to the emission mode of the laser.

[0035] In one embodiment, the compensating the photoacoustic image data based on the light flux distribution result includes:

[0036] Determine the compensation parameter of the photoacoustic image data based on the light flux distribution result;

[0037] Compensate the photoacoustic image data based on the compensation parameter.

[0038] In one embodiment, the light flux distribution result includes light flux distribution data of biological tissue at different imaging depths, and the compensating the photoacoustic image data based on the light flux distribution result includes:

[0039] Compensate the photoacoustic image data at different imaging depths based on the light flux distribution data at different imaging depths.

[0040] In one embodiment, the obtaining of the photoacoustic image data of the imaging target includes:

[0041] Perform signal processing on the photoacoustic signal to obtain the photoacoustic image data.

[0042] In one embodiment, the emitting of the laser towards the imaging target includes emitting a first laser of a first wavelength and a second laser of a second wavelength towards the imaging target, and the photoacoustic image data includes first photoacoustic image data corresponding to the first wavelength and second photoacoustic image data corresponding to the second wavelength;

[0043] The light flux distribution result includes a first light flux distribution result corresponding to the first wavelength and a second light flux distribution result corresponding to the second wavelength;

[0044] The compensating of the photoacoustic image data based on the light flux distribution result includes: compensating the first photoacoustic image data according to the first light flux distribution result to obtain compensated first photoacoustic image data, and compensating the second photoacoustic image data according to the second light flux distribution result to obtain compensated second photoacoustic image data;

[0045] The generating of the photoacoustic image according to the compensated photoacoustic image data includes: performing blood oxygen reconstruction on the compensated first photoacoustic image data and the compensated second photoacoustic image data to obtain a blood oxygen saturation image.

[0046] The second aspect of the embodiments of the present invention provides a photoacoustic imaging method, and the method includes:

[0047] Emitting a laser towards an imaging target and receiving a photoacoustic signal returned by the imaging target;

[0048] Determining an absorption coefficient of the surface tissue of the imaging target according to the photoacoustic signal;

[0049] Obtaining a light flux distribution result corresponding to the absorption coefficient of the surface tissue, where the light flux distribution result is used to characterize the light flux distribution of biological tissue at different imaging depths;

[0050] Obtaining photoacoustic image data of the imaging target;

[0051] Compensating the photoacoustic image data based on the light flux distribution result to obtain compensated photoacoustic image data;

[0052] Generating a photoacoustic image according to the compensated photoacoustic image data.

[0053] The third aspect of the embodiments of the present invention provides a photoacoustic imaging system, and the photoacoustic imaging system includes:

[0054] A photoacoustic probe;

[0055] A laser for emitting a laser towards an imaging target to cause the imaging target to return a photoacoustic signal;

[0056] A receiving circuit for controlling the photoacoustic probe to receive the photoacoustic signal;

[0057] A processor for performing the photoacoustic imaging method as described above to generate a photoacoustic image based on the photoacoustic signal;

[0058] A display for displaying the photoacoustic image.

[0059] The photoacoustic imaging method and system according to the embodiments of the present invention compensate the photoacoustic data according to the light flux distribution result corresponding to the absorption coefficient of the skin layer, which can make the light flux distribution result more in line with the actual situation of the imaging target, thereby improving the quality and accuracy of the photoacoustic image. Description of the Drawings

[0060] By describing the embodiments of the present invention in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present invention will become more obvious. The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings, the same reference numerals generally represent the same components or steps.

[0061] Figure 1 Showing a structural block diagram of a photoacoustic imaging system according to an embodiment of the present invention;

[0062] Figure 2 Showing a schematic flowchart of a photoacoustic imaging method according to an embodiment of the present invention;

[0063] Figure 3 Showing a curve graph of the absorption coefficients of different substances in the human body according to an embodiment of the present invention;

[0064] Figure 4 Showing a display interface for receiving a user's adjustment operation to determine the thickness / shape of the skin layer according to an embodiment of the present invention;

[0065] Figure 5 Showing a schematic diagram of the influence of the absorption coefficient on the light flux distribution;

[0066] Figure 6 Showing a schematic diagram of a simulated biological model according to an embodiment of the present invention;

[0067] Figure 7 Showing a schematic flowchart of a photoacoustic imaging method according to another embodiment of the present invention. Detailed Description of the Embodiments

[0068] To make the objectives, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. It should be understood that the present invention is not limited by the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0069] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present invention.

[0070] It should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to make the disclosure thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0071] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. As used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0072] To thoroughly understand the present invention, detailed structures will be presented in the following description to illustrate the technical solutions proposed by the present invention. The alternative embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may have other implementations.

[0073] Next, first refer to Figure 1 Describe a photoacoustic imaging system according to an embodiment of the present invention. Figure 1 FIG. shows a schematic structural block diagram of a photoacoustic imaging system 100 according to an embodiment of the present invention.

[0074] As Figure 1As shown, the photoacoustic imaging system 100 includes a laser 110, a photoacoustic probe 112, a transmitting circuit 114, a receiving circuit 116, a processor 118, and a display 120. Further, the photoacoustic imaging system may further include a transmit / receive selection switch 122 and a beam synthesis module 124. The transmitting circuit 114 and the receiving circuit 116 may be connected to the photoacoustic probe 112 through the transmit / receive selection switch 122.

[0075] The laser 110 is used to emit laser light towards the imaging target. After emitting the laser light towards the imaging target, the receiving circuit 116 can receive the photoacoustic signal returned by the imaging target under the excitation of the laser light through the photoacoustic probe 112. This photoacoustic signal is directly or after being processed and sent to the processor 118, and the processor 118 processes this photoacoustic signal to obtain the photoacoustic image data of the imaging target.

[0076] In one embodiment of the present application, the laser 110 may be connected to the transmit / receive selection switch 122, and the transmit / receive selection switch 122 controls the emission of laser light. The laser 120 may also be connected to the photoacoustic probe 112 through an optical conduction tool. An optical fiber bundle is coupled on the photoacoustic probe 112, and the laser light is conducted to both sides of the photoacoustic probe 110 by using the optical fiber bundle, and the imaging target is irradiated in a backlighting manner. In some implementation manners, the laser 120 and the optical fiber bundle may both be coupled inside the photoacoustic probe 112. Among them, the photoacoustic probe 112 further includes a plurality of transducer array elements for ultrasonic imaging. In this way, the photoacoustic probe 112 can be used not only for conventional ultrasonic imaging but also for photoacoustic imaging.

[0077] The plurality of transducer array elements in the photoacoustic probe 112 are arranged in a two-dimensional array, and the plurality of transducer array elements may also form a convex array. The transducer array elements are used to emit ultrasonic waves according to the excitation electrical signal, or convert the received ultrasonic waves into electrical signals. Therefore, each transducer array element can be used to realize the mutual conversion between the electrical pulse signal and the ultrasonic wave, so as to emit ultrasonic waves towards the tissue of the imaging target and can also be used to receive the ultrasonic wave echo reflected by the tissue.

[0078] When performing ultrasonic imaging, it is possible to control which transducer array elements are used to emit ultrasonic waves and which transducer array elements are used to receive ultrasonic waves through the transmit sequence and the receive sequence, or control the transducer array elements to be used to emit ultrasonic waves or receive the echo of ultrasonic waves in a time-sharing manner. The transducer array elements participating in the emission of ultrasonic waves can be simultaneously excited by electrical signals, so as to emit ultrasonic waves simultaneously; or, the transducer array elements participating in the emission of the ultrasonic beam can also be excited by several electrical signals with a certain time interval, so as to continuously emit ultrasonic waves with a certain time interval.

[0079] During the ultrasonic imaging process, the transmitting circuit 114 generates a transmission sequence under the control of the processor 118. The transmission sequence is used to control some or all of the multiple transducer elements to emit ultrasonic waves towards the target tissue. The transmission sequence parameters include the number of transducer element positions for transmission and the ultrasonic beam transmission parameters, such as amplitude, frequency, number of transmissions, transmission interval, transmission angle, waveform, focusing position, etc. In some cases, the transmitting circuit 114 is also used to perform phase delay on the transmitted beam so that different transducer elements emit ultrasonic waves at different times, so that each transmitted ultrasonic beam can be focused on a predetermined region of interest. The transmission sequence parameters corresponding to different imaging modes may be different. After the ultrasonic echo signal is received by the receiving circuit 116 and processed by subsequent modules and corresponding algorithms, ultrasonic images of different imaging modes can be generated.

[0080] The receiving circuit 116 may include one or more amplifiers, analog-to-digital converters, etc. The amplifier is used to amplify the received ultrasonic echo signal or photoacoustic signal after appropriate gain compensation, and the analog-to-digital converter is used to sample the analog echo signal at a predetermined time interval, thereby converting it into a digital signal. The digitized echo signal still retains amplitude information, frequency information, and phase information. The receiving circuit 116 sends the ultrasonic echo signal or photoacoustic signal to the beam synthesis module 124 for processing.

[0081] The beam synthesis module 124 performs processing such as focusing delay, weighting, and channel summation on the ultrasonic echo signal or photoacoustic signal, and then sends it to the processor 118. The processor 118 performs signal detection, signal enhancement, data conversion, logarithmic compression, etc. on the ultrasonic echo signal or photoacoustic signal to form an ultrasonic image or a photoacoustic image. The ultrasonic image or photoacoustic image obtained by the processor 118 can be displayed on the display 120 or stored in the memory 124.

[0082] Optionally, the processor 118 can be implemented as software, hardware, firmware, or any combination thereof, and can use one or more application specific integrated circuits (ASICs), one or more general integrated circuits, one or more microprocessors, one or more programmable logic devices, or any combination of the foregoing circuits and / or devices, or other suitable circuits or devices. Also, the processor 118 can control other components in the photoacoustic imaging system 100 to perform the corresponding steps of the methods in the various embodiments of this specification.

[0083] The display 120 is connected to the processor 118. The display 120 can be a touch display screen, a liquid crystal display screen, etc.; or, the display 120 can be an independent display such as a liquid crystal display or a television outside the photoacoustic imaging system 100; or, the display 120 can be the display screen of an electronic device such as a smart phone or a tablet computer, etc. Among them, the number of displays 120 can be one or more.

[0084] The display 120 can display the ultrasonic image or the photoacoustic image obtained by the processor 118. In addition, while displaying the ultrasonic image or the photoacoustic image, the display 120 can also provide a graphical interface for the user to perform human-computer interaction. One or more controlled objects are set on the graphical interface, and the user is provided with an input operation instruction through the human-computer interaction device to control these controlled objects, so as to execute corresponding control operations. For example, an icon is displayed on the graphical interface, and the icon can be operated by using the human-computer interaction device to perform a specific function, such as drawing a region of interest box on the ultrasonic image, etc.

[0085] Optionally, the photoacoustic imaging system 100 can further include other human-computer interaction devices outside the display 120, which are connected to the processor 118. For example, the processor 118 can be connected to the human-computer interaction device through an external input / output port. The external input / output port can be a wireless communication module, a wired communication module, or a combination of both. The external input / output port can also be implemented based on USB, bus protocols such as CAN, and / or wired network protocols, etc.

[0086] Among them, the human-computer interaction device can include an input device for detecting the input information of the user. The input information can be, for example, a control instruction for the ultrasonic emission / reception timing, an operation input instruction for drawing points, lines, or boxes on the ultrasonic image or the photoacoustic image, or can also include other instruction types. The input device can include one or a combination of multiple of a keyboard, a mouse, a roller, a trackball, a mobile input device (such as a mobile device with a touch display screen, a mobile phone, etc.), a multi-functional knob, etc. The human-computer interaction device can also include an output device such as a printer.

[0087] The photoacoustic imaging system 100 can further include a memory 124 for storing instructions executed by the processor, storing received ultrasonic echoes or photoacoustic signals, storing ultrasonic images or photoacoustic images, etc. The memory can be a flash memory card, a solid-state memory, a hard disk, etc. It can be a volatile memory and / or a non-volatile memory, a removable memory and / or a non-removable memory, etc.

[0088] It should be understood, Figure 1The components included in the photoacoustic imaging system 100 shown are only schematic, and it may include more or fewer components. The present invention is not limited thereto.

[0089] Next, a photoacoustic imaging method according to an embodiment of the present invention will be described with reference to Figure 2 Describe a photoacoustic imaging method according to an embodiment of the present invention. Figure 2 It is a schematic flowchart of a photoacoustic imaging method 200 according to an embodiment of the present invention.

[0090] As Figure 2 shown, a photoacoustic imaging method 200 according to an embodiment of the present invention includes the following steps:

[0091] In step S210, a laser is emitted towards the imaging target, and a photoacoustic signal returned by the imaging target is received;

[0092] In step S220, the light intensity of the laser is determined, and an absorption coefficient of the skin layer of the imaging target is determined according to the photoacoustic signal and the light intensity of the laser;

[0093] In step S230, a light flux distribution result corresponding to the absorption coefficient of the skin layer is obtained, and the light flux distribution result is used to characterize the light flux distribution of biological tissue at different imaging depths;

[0094] In step S240, photoacoustic image data of the imaging target is obtained;

[0095] In step S250, the photoacoustic image data is compensated based on the light flux distribution result to obtain compensated photoacoustic image data;

[0096] In step S260, a photoacoustic image is generated according to the compensated photoacoustic image data.

[0097] According to the photoacoustic imaging method 200 according to an embodiment of the present invention, compensating the photoacoustic data according to the light flux distribution result corresponding to the absorption coefficient of the skin layer can make the light flux distribution result more in line with the actual situation of the imaging target, thereby improving the quality and accuracy of the photoacoustic image.

[0098] Considering that the laser first acts on the human skin, and there are significant differences in the skin thickness and the melanin content on the skin among different individuals and different parts, and as Figure 3 shown, melanin has the strongest light scattering and light absorption in the entire imaging area, resulting in a large difference in the light flux under the skin among different individuals or different parts. Adaptively adjusting the light flux distribution result according to the individual differences of the skin layer can greatly improve the accuracy of the light flux distribution result.

[0099] The parameters of the skin layer mainly include the optical parameters and morphological parameters of the skin layer. The morphological parameters mainly include shape and thickness, and the optical parameters mainly include the absorption coefficient. In the embodiments of the present invention, the absorption coefficient of the skin layer is determined according to the photoacoustic signal. Specifically, in step S210, a laser is emitted to the imaging target, and the photoacoustic signal returned by the imaging target is received; the light intensity of the laser is determined, and the absorption coefficient of the skin layer of the imaging target is determined according to the photoacoustic signal and the light intensity of the laser.

[0100] Among them, the laser can be emitted to the imaging target through the optical fiber bundle coupled to the photoacoustic probe. When the imaging target absorbs light energy, it will cause temperature rise and thermal expansion, thereby generating a photoacoustic signal that propagates outward. Exemplarily, after the laser generates a laser pulse, feedback information can be returned to the processor of the photoacoustic imaging system. The feedback information can include the actual transmission time of the laser pulse. The processor can calculate the interval duration for receiving the photoacoustic signal according to a preset algorithm, and control the photoacoustic probe to receive the photoacoustic signal returned from the imaging target through the receiving circuit.

[0101] Since the magnitude of the signal intensity p of the photoacoustic signal is related to the absorption coefficient u a and the light flux F, that is, p ∝ u a F, and the light flux F can be determined according to the light intensity of the laser. Therefore, in step S220, the light intensity of the laser is determined, and the absorption coefficient of the skin layer of the imaging target is determined according to the photoacoustic signal and the light intensity of the laser.

[0102] Specifically, the initial sound pressure p0 generated by the skin layer absorbing light energy is p0 = Γη th u a F. In the formula, Γ is the dimensionless parameter Grueneisen coefficient, which represents the thermodynamic characteristics of the absorbing substance, and η th represents the conversion efficiency of converting into heat energy. Both are approximately constants in human applications. u a is the absorption coefficient, and F is the light flux. It can be seen from the formula that the magnitude of the photoacoustic signal is proportional to the absorption coefficient u a and the light flux F. As long as the light flux is known, the absorption coefficient u of the skin layer can be solved according to the magnitude of the initial sound pressure p0 a , and because the initial light illumination of the skin layer is outside the body, the light flux F of the skin layer can be obtained more accurately by measuring the light intensity of the external excitation light source.

[0103] Based on the above principle, determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser includes: determining the initial sound pressure p0 generated by the skin layer absorbing light energy according to the photoacoustic signal; determining the light flux F of the skin layer according to the light intensity of the laser; determining the absorption coefficient u of the skin layer according to the initial sound pressure p0 and the light flux F a , where the absorption coefficient u ais proportional to the initial sound pressure p0 and inversely proportional to the light flux F, i.e., u a = p0 / Γη th F. Among them, the photoacoustic signals during the diffusion process can be superimposed to obtain the initial sound pressure p0 before diffusion. And the light intensity of the laser can be measured by an optical sensor, which can be integrated inside the laser or be an independent optical sensor. The embodiments of the present invention do not limit this.

[0104] Further, during the photoacoustic imaging process, at least two different wavelengths of lasers are required for photoacoustic imaging to obtain photoacoustic image data corresponding to the lasers of different wavelengths. Therefore, a first laser with a first wavelength can be emitted to the imaging target, and a first photoacoustic signal corresponding to the first laser is received. And a second laser with a second wavelength is emitted to the imaging target, and a second photoacoustic signal corresponding to the second laser is received. Among them, the first wavelength is different from the second wavelength. For example, the first laser is a short wavelength and the second laser is a long wavelength. Specifically, the laser can be controlled to alternately emit the first laser and the second laser to the imaging target to obtain the first photoacoustic signal and the second photoacoustic signal returned by the imaging target. Determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser can include determining the absorption coefficient according to the light intensity of the first laser and the first photoacoustic signal, determining the absorption coefficient according to the light intensity of the second laser and the second photoacoustic signal, or determining the absorption coefficient jointly according to the light intensities of the first laser and the second laser, the first photoacoustic signal and the second photoacoustic signal.

[0105] Exemplarily, since the morphological parameters such as the shape and thickness of the skin layer also affect the light flux distribution result, in addition to the absorption coefficient, the morphological characteristics such as the thickness and shape of the skin layer can also be determined, so as to select the light flux distribution result corresponding to the thickness, shape, etc. of the skin layer.

[0106] Exemplarily, the shape and / or thickness of the skin layer can be determined according to the ultrasonic image of the imaging target. Among them, the system can perform image recognition to automatically determine the shape and / or thickness of the skin layer, or the ultrasonic image of the imaging target can be displayed, and the shape and / or thickness of the skin layer can be determined in combination with the user's manual operation. The ultrasonic image can also be superimposed with the photoacoustic image before correction of the imaging target, so as to more clearly present the position of the skin layer. The ultrasonic image can also be superimposed with the photoacoustic image corrected according to the light flux distribution result, and the light flux distribution result and the photoacoustic image are updated in real time after determining the shape and thickness of the skin layer.

[0107] Such as Figure 4As shown, a first identifier 410 can be displayed in the ultrasonic image along the boundary of the skin layer; a regulation operation on the first identifier 410 is received, and the thickness and / or shape of the skin layer is determined according to the regulated first identifier 410. Specifically, the first identifier 410 can include an identifier extending along the upper surface of the skin layer and an identifier extending along the lower surface of the skin layer. A user can manually regulate the first identifier 410 to draw the shape and thickness of the skin layer.

[0108] Alternatively, a second identifier 420 can also be displayed in the ultrasonic image along the thickness direction of the skin layer, a regulation operation on the second identifier 420 is received, and the thickness of the skin layer is determined according to the regulated second identifier 420. Specifically, the second identifier 420 extends from the upper surface of the skin layer to the lower surface of the skin layer, and its length represents the thickness of the skin layer. A user can regulate the position of the second identifier 420 to measure the maximum thickness or minimum thickness of the skin layer.

[0109] Next, in step S230, a light flux distribution result corresponding to the absorption coefficient of the skin layer is obtained, and the light flux distribution result is used to characterize the light flux distribution of biological tissue at different imaging depths. As Figure 5 shown, the skin layer with a higher melanin content has a higher absorption coefficient, and the skin layer with a lower melanin content has a lower absorption coefficient, and the corresponding light flux distribution results of the two are also different. Therefore, obtaining the corresponding light flux distribution result according to the absorption coefficient of the skin layer can make the light flux distribution result more in line with the real situation of the imaging target.

[0110] In one embodiment, obtaining the light flux distribution result corresponding to the absorption coefficient of the skin layer includes: obtaining a preset light flux distribution result; correcting the preset light flux distribution result according to the absorption coefficient of the skin layer to obtain the light flux distribution result corresponding to the absorption coefficient of the skin layer. Further, the preset light flux distribution result can also be corrected according to the thickness and / or shape of the skin layer to obtain the light flux distribution result corresponding to the thickness and / or shape of the skin layer. Among them, the preset light flux distribution result can be obtained by pre-simulating photoacoustic imaging of a simulated target tissue. Correcting the preset light flux distribution result according to the absorption coefficient of the skin layer requires less computing amount, can ensure the computing speed while improving the accuracy of the light flux distribution result, and improve the examination efficiency of doctors.

[0111] Exemplarily, the light flux distribution result also corresponds to the biological tissue type of the imaging target, that is, a preset light flux distribution result corresponding to the biological tissue type of the imaging target can be obtained and corrected according to the absorption coefficient of the skin layer. Specifically, multiple simulated target tissues can be pre-simulated for imaging. During the simulation imaging process, laser irradiation of the simulated target tissues is simulated, so as to obtain the light flux distribution results of each simulated target tissue, and record the corresponding relationship between the light flux distribution results and the biological tissue types of the simulated target tissues. During the actual imaging process, the light flux distribution result of the simulated target tissue most similar to it is retrieved from the database according to the biological tissue type of the imaging target, and used to optimize the photoacoustic image.

[0112] Exemplarily, before photoacoustic imaging of the imaging target, first obtain the ultrasonic image data of the imaging target, determine the biological tissue type of the imaging target according to the ultrasonic image data, so as to select the light flux distribution result corresponding to the biological tissue type. Specifically, before photoacoustic imaging, first enter the ultrasonic imaging mode, such as the tissue imaging mode (i.e., B mode). In the tissue imaging mode, control the ultrasonic probe to emit ultrasonic waves to the imaging target, receive the ultrasonic echo signal, and perform processing such as logarithmic compression, dynamic range adjustment, and digital scan conversion on the ultrasonic echo signal to obtain the ultrasonic image data for reflecting the tissue morphological structure of the imaging target.

[0113] After obtaining the ultrasonic image data of the imaging target, determine the biological tissue type of the imaging target based on the ultrasonic image data, so as to facilitate the selection of the light flux distribution result suitable for the imaging target. The biological tissue type can be the organ or part corresponding to the imaging target, etc. For example, the biological tissue type of the imaging target can be determined as thyroid tissue, breast tissue or other organs or parts based on the ultrasonic imaging data. Or, the biological tissue type can be the structural type of the imaging target. For example, the imaging target simply includes a skin layer and a homogeneous tissue layer, or the imaging target includes a skin layer, a muscle layer, a blood vessel layer, etc., or the structural type of the imaging target can be further refined. The photoacoustic imaging system can preset multiple structural types of imaging targets and determine the actual corresponding structural type of the imaging target according to the ultrasonic image. The acquisition method of this biological tissue type can be automatic recognition based on machine learning, neural network training models, etc., or can be manually determined by the user based on the characteristics of the ultrasonic image data and the structure displayed on the interface of the ultrasonic image data.

[0114] Exemplarily, simulation analysis software such as COMSOL can be used to perform simulation imaging on the simulated target tissue. As Figure 6As shown, during the simulation imaging process, it is necessary to construct a simulation target tissue model corresponding to the biological tissue type according to the clinical use scenario of photoacoustic imaging, and construct a simulated laser light source above the simulation target tissue to simulate laser irradiation of the simulation target tissue. Among them, two fiber bundles are arranged on both sides of the photoacoustic probe, and the laser source is incident at a certain angle in the plane and vertical direction of the photoacoustic probe through two optical fibers, ensuring that the two-dimensional detection surface of the photoacoustic probe and the irradiation area of the fiber bundle maintain a coplanar mode during the imaging process. In one embodiment, the light flux distribution result also corresponds to the emission mode of the laser. The emission mode of the laser includes the spacing, angle, etc. of the light source. During the simulation imaging process, different laser emission modes can be simulated so as to select the light flux distribution results corresponding to different laser emission modes subsequently.

[0115] In one embodiment, the simulation target tissue is at least divided into a skin layer and a tissue layer. The thickness and absorption coefficient of the skin layer can be adjusted according to actual needs. Below the skin layer are other background tissues, such as the breast layer, thyroid layer, etc. In some embodiments, the simulation target tissue can be divided into three layers: a gel cushion layer, a skin layer, and a breast layer. The gel pad is a colorless, transparent, and sound-conducting material that can make the laser propagate basically in a straight line, and at the same time has extremely low attenuation to sound. Clinically, it is used to better fit the imaging site and improve the quality of photoacoustic images.

[0116] Next, obtain the constraint conditions describing the propagation characteristics of the laser in the simulation target tissue, and solve according to the biological tissue information and constraint conditions of the simulation target tissue to obtain the light flux distribution result of the laser incident on the simulation target tissue. Exemplarily, the constraint conditions include the following diffusion equation:

[0117]

[0118] Among them, is the light flux per unit time, u a is the absorption coefficient, D is calculated according to the absorption coefficient and scattering coefficient, and S is the energy of the incident light source.

[0119] After the equation is input in the simulation software, grid division and calculation are performed, and the two-dimensional light flux distribution result of the simulation target tissue relative to the body surface at different imaging depths can be obtained. Further, the one-dimensional light flux distribution result of the simulation target tissue relative to the body surface at different imaging depths can also be obtained. The one-dimensional light flux distribution result can be the one-dimensional light flux distribution result at the center position of the simulated imaging section in the simulation target tissue. The one-dimensional light flux distribution result can also be the one-dimensional light flux distribution result obtained by statistically analyzing the light flux distribution data at multiple positions on the simulated imaging section. The one-dimensional distribution result of this light flux can actually be regarded as a compensation surface because for the photoacoustic data at the same depth, the compensation parameter of the light flux is the same.

[0120] In some embodiments, the light flux distribution result corresponding to the biological tissue type can be determined in combination with user interaction. Specifically, options for at least two alternative light flux distribution results can be provided on the display interface, a selection instruction for the above options can be received, and the light flux distribution result corresponding to the actual biological tissue type of the imaging target can be determined from the alternative light flux distribution results according to the received selection instruction.

[0121] Alternatively, image recognition can also be performed on the ultrasonic image data to automatically obtain the biological tissue type and parameter information of the imaging target, and the corresponding light flux distribution result can be obtained according to the biological tissue type and parameter information, thus eliminating the need for manual measurement by the user and improving the measurement efficiency.

[0122] In another embodiment, obtaining the light flux distribution result corresponding to the absorption coefficient of the skin layer includes: selecting, from a plurality of pre-stored light flux distribution results, the light flux distribution result corresponding to the absorption coefficient of the skin layer, where the plurality of light flux distribution results are obtained by pre-simulating the imaging of simulation target tissues corresponding to different absorption coefficients. Exemplarily, when simulating the imaging of the simulation target tissue, simulation target tissues with different absorption coefficients of the skin layer can be set to obtain light flux distribution results corresponding to different absorption coefficients, and only a suitable light flux distribution result needs to be selected during the actual photoacoustic imaging process, thereby improving the imaging speed.

[0123] In yet another embodiment, real-time simulation imaging can also be performed on the simulation target tissue corresponding to the absorption coefficient of the skin layer to obtain the light flux distribution result corresponding to the absorption coefficient of the skin layer. Real-time simulation imaging can include inputting various parameters such as the biological tissue type of the imaging target and the absorption coefficient of the skin layer into the simulation model to obtain a more accurate light flux distribution result.

[0124] In step S240, photoacoustic image data of the imaging target is obtained. Specifically, the photoacoustic signal obtained in step S210 can be signal-processed to obtain the photoacoustic image data, that is, the absorption coefficient of the skin layer and the photoacoustic imaging of the imaging target are determined based on the same set of photoacoustic signals. After receiving the photoacoustic signal, the noise in the photoacoustic signal can be removed, and then through processes such as beamforming and image reconstruction, the photoacoustic image data of the imaging target is obtained. Alternatively, a laser can also be re-emitted to the imaging target, the photoacoustic signal returned by the imaging target is received, and the photoacoustic image data is obtained based on the photoacoustic signal, that is, the absorption coefficient of the skin layer and the photoacoustic imaging of the imaging target are determined based on different sets of photoacoustic signals.

[0125] Next, in step S250, the photoacoustic image data is compensated based on the light flux distribution result to obtain the compensated photoacoustic image data.

[0126] Among them, the compensation parameters of the photoacoustic image data can be determined based on the light flux distribution result, and the photoacoustic image data can be compensated according to the compensation parameters. The light flux distribution result includes the light flux distribution data of biological tissues at different imaging depths, and the photoacoustic image data at different imaging depths can be compensated based on the light flux distribution data at different imaging depths. Among them, when the light flux distribution result is a one-dimensional light flux distribution result, the light flux data at different imaging depths can be obtained according to the light flux distribution result, and the light flux data at different imaging depths are determined as the compensation parameters at the corresponding depths, so as to obtain one-dimensional compensation parameters. When the light flux distribution result is a two-dimensional light flux distribution result, the light flux data at different imaging depths and different widths can be obtained according to the light flux distribution result, and the light flux data at different imaging depths and different widths are determined as the compensation parameters at the corresponding imaging depths and corresponding widths, so as to obtain two-dimensional compensation parameters. Or, other operations can also be performed on the light flux distribution result to obtain the compensation parameters of the photoacoustic image data.

[0127] Exemplarily, according to the photoacoustic effect principle, the light absorption energy density A(r) under short-pulse laser can be described as: A(r) = μ(r) × F(r), that is

[0128] μ(r) = A(r) / F(r)

[0129] where r represents the position coordinate, F represents the light flux, and μ represents the absorption coefficient.

[0130] Therefore, when the compensation parameter is a one-dimensional compensation parameter, dividing the photoacoustic image data at different imaging depths by the compensation parameter at the corresponding depth can obtain the compensated photoacoustic image data. When the compensation parameter is a two-dimensional compensation parameter, dividing the photoacoustic image data at different imaging depths and different widths by the compensation parameter at the corresponding depth and corresponding width can obtain the compensated photoacoustic image data.

[0131] Exemplarily, when the photoacoustic image data includes first photoacoustic image data and second photoacoustic image data corresponding to lasers of different wavelengths, when performing simulation imaging on the simulated target tissue, lasers of different wavelengths are simulated to irradiate the simulated target tissue, and light flux distribution results corresponding to lasers of different wavelengths are obtained, that is, a first light flux distribution result corresponding to the first wavelength and a second light flux distribution result corresponding to the second wavelength. When compensating the photoacoustic image data based on the light flux distribution result, the first photoacoustic image data is compensated according to the first light flux distribution result, and the second photoacoustic image data is compensated according to the second light flux distribution result, so as to obtain the compensated first photoacoustic image data and second photoacoustic image data respectively.

[0132] Finally, in step S260, an optoacoustic image is generated based on the compensated optoacoustic image data. Specifically, blood oxygen reconstruction can be performed on the compensated first optoacoustic image data and the compensated second optoacoustic image data to obtain a blood oxygen saturation image.

[0133] Oxygen Saturation (SaO2) refers to the percentage of oxyhemoglobin content in the blood accounting for all the bindable hemoglobin, that is, the concentration of blood oxygen. Clinically, arterial oxygen saturation is detected to evaluate the oxygen content in the blood. In different physiological states of the human body, the metabolic conditions of various organs and tissues are different, and the need for blood flow is also different. For example, compared with normal tissues, cancerous tissues usually exhibit the characteristics of "high blood and low oxygen". Based on the dual-wavelength tissue detection technology of photoacoustic imaging, that is, according to the different optical absorption characteristics of oxyhemoglobin and deoxyhemoglobin in the near-infrared light region, blood flow signals and their blood oxygen saturation in human tissues are detected by emitting two specific wavelengths of infrared light. Furthermore, by comparing the blood oxygen content in diseased tissues and healthy tissues, the benign and malignant nature of the mass can be determined.

[0134] Specifically, according to the pixel values of each pixel point in the compensated first optoacoustic image data and the compensated second optoacoustic image data, and according to the extinction coefficient of deoxyhemoglobin corresponding to the first laser, the extinction coefficient of oxyhemoglobin corresponding to the first laser, the extinction coefficient of deoxyhemoglobin corresponding to the second laser, and the extinction coefficient of oxyhemoglobin corresponding to the second laser, the content of deoxyhemoglobin corresponding to each pixel point and the content of oxyhemoglobin corresponding to each pixel point can be obtained. SO2 is the blood oxygen saturation of the target pixel point, and the blood oxygen saturation corresponding to each pixel point is obtained according to the content of deoxyhemoglobin and oxyhemoglobin corresponding to each pixel point.

[0135] After that, the value of the blood oxygen saturation corresponding to each pixel point can be used as the pixel value of the pixel point, or the value of the blood oxygen saturation of each pixel point is calculated according to a preset algorithm to obtain the pixel value of the pixel point. According to the pixel values of each pixel point, the blood oxygen saturation image of the imaging target can be obtained.

[0136] In summary, the photoacoustic imaging method 200 of the embodiments of the present invention takes into account the individual differences of the imaging target, selects the skin layer signal that is easy to measure and has a greater impact as the optimized feedback value, compensates the photoacoustic data according to the light flux distribution result corresponding to the absorption coefficient of the skin layer. In addition, the thickness / shape of the skin layer can be determined in combination with user interaction to select a suitable light flux distribution result, further increasing the applicability and accuracy of the light flux correction process.

[0137] Next, reference will be made to Figure 7 Describe a photoacoustic imaging method according to another embodiment of the present invention.Figure 7 It is a schematic flowchart of a photoacoustic imaging method 700 according to an embodiment of the present invention.

[0138] As Figure 7 shown, the photoacoustic imaging method 700 according to an embodiment of the present invention includes the following steps:

[0139] In step S710, a laser is emitted towards the imaging target, and the photoacoustic signal returned by the imaging target is received;

[0140] In step S720, the absorption coefficient of the surface tissue of the imaging target is determined according to the photoacoustic signal;

[0141] In step S730, a light flux distribution result corresponding to the absorption coefficient of the surface tissue is obtained, and the light flux distribution result is used to characterize the light flux distribution of biological tissue at different imaging depths;

[0142] In step S740, the photoacoustic image data of the imaging target is obtained;

[0143] In step S750, the photoacoustic image data is compensated based on the light flux distribution result to obtain compensated photoacoustic image data;

[0144] In step S760, a photoacoustic image is generated according to the compensated photoacoustic image data.

[0145] The main difference between the photoacoustic imaging method 700 according to the embodiment of the present invention and the photoacoustic imaging method 200 described above is that, firstly, the surface tissue of the imaging target is not limited to the skin layer. For example, in the application scenario of endovascular imaging, the laser light source does not directly act on the skin, but acts on the inner wall of the blood vessel. At this time, the surface tissue is the inner wall of the blood vessel, and the absorption coefficient of the inner wall of the blood vessel can also be determined according to the photoacoustic signal to obtain the corresponding light flux distribution result. Secondly, when calculating the absorption coefficient of the surface tissue, the light intensity of the laser can be not measured. For example, the default light intensity can be used in combination with the photoacoustic signal to determine the absorption coefficient of the surface tissue. More specific details of the photoacoustic imaging method 700 according to the embodiment of the present invention can refer to the relevant description of the photoacoustic imaging method 200, which will not be elaborated here.

[0146] The photoacoustic imaging method 700 according to the embodiment of the present invention compensates the photoacoustic data according to the light flux distribution result corresponding to the absorption coefficient of the surface tissue, which can make the light flux distribution result more in line with the actual situation of the imaging target, thereby improving the quality and accuracy of the photoacoustic image.

[0147] The embodiment of the present invention also provides a photoacoustic imaging system for implementing the above-mentioned photoacoustic imaging method 200 or photoacoustic imaging method 700. Now referring back to Figure 1 , the photoacoustic imaging system can be implemented asFigure 1 The photoacoustic imaging system 100 shown. The photoacoustic imaging system 100 may include a laser 110, a photoacoustic probe 112, a transmitting circuit 114, a receiving circuit 116, a processor 118, and a display 120. Optionally, the photoacoustic imaging system 100 may further include a transmit / receive selection switch 122 and a beam synthesis module 124. The transmitting circuit 114 and the receiving circuit 116 may be connected to the photoacoustic probe 112 through the transmit / receive selection switch 122. The laser 110 is used to emit laser light to an imaging target, causing the imaging target to return a photoacoustic signal; the receiving circuit 116 is used to control the photoacoustic probe 112 to receive the photoacoustic signal; the processor 118 is used to execute the photoacoustic imaging method 200 or the photoacoustic imaging method 700 as described above to generate a photoacoustic image based on the photoacoustic signal. The display 120 is used to display the photoacoustic image. The relevant descriptions of each component can refer to the relevant descriptions above and will not be elaborated here.

[0148] Only the main functions of the components of the photoacoustic imaging system are described above. For more details, refer to the relevant descriptions of the photoacoustic imaging method 200 and the photoacoustic imaging method 700. The photoacoustic imaging system 100 of the embodiments of the present invention compensates the photoacoustic data according to the light flux distribution result corresponding to the absorption coefficient of surface tissues such as skin layers, which can make the light flux distribution result more in line with the actual situation of the imaging target, thereby improving the quality and accuracy of the photoacoustic image.

[0149] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present invention thereto. Those of ordinary skill in the art can make various changes and modifications therein without departing from the scope and spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as claimed in the appended claims.

[0150] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the present invention.

[0151] In several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0152] In the specification provided herein, a number of specific details are set forth. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail so as not to obscure an understanding of the present specification.

[0153] Similarly, it should be understood that in order to streamline the present invention and assist in understanding one or more of the various inventive aspects, in the description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present invention should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the corresponding claims, the inventive point lies in that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim itself serves as a separate embodiment of the present invention.

[0154] Those skilled in the art will appreciate that, except where features are mutually exclusive, any combination can be employed of all the features disclosed in this specification (including the accompanying claims, abstract and drawings) and all the processes or units of any method or apparatus so disclosed. Each feature disclosed in this specification (including the accompanying claims, abstract and drawings), unless otherwise expressly stated, may be replaced by alternative features serving the same, equivalent or similar purpose.

[0155] In addition, those skilled in the art will be able to understand that although some of the embodiments described herein include certain features included in other embodiments but not others, the combination of features of different embodiments means that it is within the scope of the present invention and forms different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0156] Each component embodiment of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some modules according to the embodiments of the present invention. The present invention can also be implemented as a device program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present invention can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier signal, or in any other form.

[0157] It should be noted that the above embodiments illustrate the present invention rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claims. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In the unit claims listing several devices, several of these devices can be embodied by the same item of hardware. The use of first, second, and third, etc. does not denote any order. These words can be interpreted as names.

[0158] As described above, it is only the specific implementation manner of the present invention or the description of the specific implementation manner. The protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all of them should be covered by the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A photoacoustic imaging method, characterized in that, The method includes: Emitting a laser towards an imaging target and receiving a photoacoustic signal returned by the imaging target; Determining the light intensity of the laser, and determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser; Obtaining a light flux distribution result corresponding to the absorption coefficient of the skin layer, where the light flux distribution result is used to characterize the light flux distribution of biological tissue at different imaging depths; Obtaining photoacoustic image data of the imaging target; Compensating the photoacoustic image data based on the light flux distribution result to obtain compensated photoacoustic image data; Generating a photoacoustic image according to the compensated photoacoustic image data.

2. The photoacoustic imaging method according to claim 1, characterized in that The determining the absorption coefficient of the skin layer of the imaging target according to the photoacoustic signal and the light intensity of the laser includes: Determining an initial sound pressure generated by the skin layer absorbing light energy according to the photoacoustic signal; Determining the light flux of the skin layer according to the light intensity of the laser; Determining the absorption coefficient of the skin layer according to the initial sound pressure and the light flux, where the absorption coefficient is proportional to the initial sound pressure and inversely proportional to the light flux.

3. The photoacoustic imaging method according to claim 1 or 2, characterized in that The determining the light intensity of the laser includes: Measuring the light intensity of the laser through an optical sensor.

4. The photoacoustic imaging method according to claim 1, wherein The method further includes: Determining the thickness and / or shape of the skin layer, and the light flux distribution result also corresponds to the thickness and / or shape of the skin layer.

5. The photoacoustic imaging method according to claim 4, characterized in that The determining the thickness and / or shape of the skin layer includes: Displaying an ultrasonic image of the imaging target and displaying a first identifier set along the boundary of the skin layer in the ultrasonic image; Receiving an adjustment operation on the first identifier and determining the thickness and / or shape of the skin layer according to the adjusted first identifier.

6. The photoacoustic imaging method according to claim 4, characterized in that The determining the thickness of the skin layer includes: Displaying an ultrasonic image of the imaging target and displaying a second identifier set along the thickness direction of the skin layer in the ultrasonic image; Receiving an adjustment operation on the second identifier and determining the thickness of the skin layer according to the adjusted second identifier.

7. The photoacoustic imaging method according to claim 5 or 6, characterized in that The method further includes: superimposing and displaying a photoacoustic image of the imaging target before correction on the ultrasonic image.

8. The photoacoustic imaging method according to claim 1, wherein The obtaining the light flux distribution result corresponding to the absorption coefficient of the skin layer includes: Obtaining a preset light flux distribution result; Correcting the preset light flux distribution result according to the absorption coefficient of the skin layer to obtain a light flux distribution result corresponding to the absorption coefficient of the skin layer.

9. The photoacoustic imaging method according to claim 1, wherein The obtaining the light flux distribution result corresponding to the absorption coefficient of the skin layer includes: Selecting, from a plurality of pre-stored light flux distribution results, a light flux distribution result corresponding to the absorption coefficient of the skin layer, where the plurality of light flux distribution results are obtained by pre-simulating imaging of simulation target tissues corresponding to different absorption coefficients; Or, simulating imaging of a simulation target tissue corresponding to the absorption coefficient of the skin layer in real time to obtain a light flux distribution result corresponding to the absorption coefficient of the skin layer.

10. The photoacoustic imaging method according to claim 1, wherein The light flux distribution result also corresponds to the type of biological tissue of the imaging target.

11. The photoacoustic imaging method according to claim 1, wherein The light flux distribution result also corresponds to the emission mode of the laser.

12. The photoacoustic imaging method according to claim 1, wherein Compensating the photoacoustic image data based on the light flux distribution result includes: Determining compensation parameters of the photoacoustic image data based on the light flux distribution result; Compensating the photoacoustic image data based on the compensation parameters.

13. The photoacoustic imaging method according to claim 1, wherein The light flux distribution result includes light flux distribution data of biological tissue at different imaging depths. Compensating the photoacoustic image data based on the light flux distribution result includes: Compensating the photoacoustic image data at different imaging depths based on the light flux distribution data at different imaging depths.

14. The photoacoustic imaging method according to claim 1, characterized in that, Obtaining the photoacoustic image data of the imaging target includes: Performing signal processing on the photoacoustic signal to obtain the photoacoustic image data.

15. The photoacoustic imaging method according to claim 14, wherein Emitting laser to the imaging target includes emitting a first laser with a first wavelength and a second laser with a second wavelength to the imaging target. The photoacoustic image data includes first photoacoustic image data corresponding to the first wavelength and second photoacoustic image data corresponding to the second wavelength; The light flux distribution result includes a first light flux distribution result corresponding to the first wavelength and a second light flux distribution result corresponding to the second wavelength; Compensating the photoacoustic image data based on the light flux distribution result includes: compensating the first photoacoustic image data according to the first light flux distribution result to obtain compensated first photoacoustic image data, and compensating the second photoacoustic image data according to the second light flux distribution result to obtain compensated second photoacoustic image data; Generating a photoacoustic image according to the compensated photoacoustic image data includes: performing blood oxygen reconstruction on the compensated first photoacoustic image data and the compensated second photoacoustic image data to obtain a blood oxygen saturation image.

16. A photoacoustic imaging method, characterized in that, The method includes: Emitting laser to an imaging target and receiving a photoacoustic signal returned by the imaging target; Determining an absorption coefficient of the surface tissue of the imaging target according to the photoacoustic signal; Obtaining a light flux distribution result corresponding to the absorption coefficient of the surface tissue, where the light flux distribution result is used to characterize the light flux distribution of biological tissue at different imaging depths; Obtaining the photoacoustic image data of the imaging target; Compensating the photoacoustic image data based on the light flux distribution result to obtain compensated photoacoustic image data; Generating a photoacoustic image according to the compensated photoacoustic image data.

17. A photoacoustic imaging system, characterized in that, The photoacoustic imaging system includes: A photoacoustic probe; A laser for emitting laser to an imaging target to make the imaging target return a photoacoustic signal; A receiving circuit for controlling the photoacoustic probe to receive the photoacoustic signal; A processor for executing the photoacoustic imaging method according to any one of claims 1 - 16 to generate a photoacoustic image based on the photoacoustic signal; A display for displaying the photoacoustic image.

Images