WO2017124912A1

WO2017124912A1 - Double-focusing ultrasonic probe and sparse array photo-acoustic tomography system

Info

Publication number: WO2017124912A1
Application number: PCT/CN2016/113860
Authority: WO
Inventors: 孟静; 宋亮; 孙明健; 林日强; 禹继国
Original assignee: 中国科学院深圳先进技术研究院; 曲阜师范大学
Priority date: 2016-01-21
Filing date: 2016-12-30
Publication date: 2017-07-27
Also published as: CN105595964B; CN105595964A

Abstract

A double-focusing ultrasonic probe (1) and a sparse array photo-acoustic tomography system. The probe (1) comprises a recessed detection face (11), and a numerical aperture of the recessed detection face (11) in a first direction (13) is greater than that in a second direction (12), so that a signal receiving angle of the recessed detection face (11) in the first direction (13) is greater than that in the second direction (12), and the length of a focused area of the recessed detection face (11) in the second direction (12) is greater than that in the first direction (13), wherein the first direction (13) is perpendicular to the second direction (12).

Description

Dual-focus ultrasound probe and sparse array photoacoustic tomography system

Technical field

The present disclosure relates to the field of photoacoustic imaging technology, for example, to a dual focus ultrasound probe and a sparse array photoacoustic tomography system.

Background technique

The photoacoustic imaging method is a non-destructive, in vivo biomedical imaging method that combines the characteristics of both optical and ultrasonic imaging modes, combining high contrast and spectral specificity of optical imaging and high spatial depth imaging of ultrasound. Resolution is one of the fastest growing biomedical imaging technologies. The photoacoustic imaging method can invert the deposition of light energy in the tissue by detecting the ultrasonic signal generated by the instantaneous thermal expansion after the biological tissue absorbs the pulsed laser. The imaging method can realize the disease-related physiological functions and parameter imaging in the living body, such as hemoglobin concentration, blood oxygen concentration, oxygen metabolism, etc., without relying on the light absorption contrast of the tissue itself in the absence of the exogenous contrast agent. . Photoacoustic imaging methods can be applied to many aspects of biomedical fields such as tumor angiogenesis research, hemoglobin and blood oxygen concentration imaging, breast cancer diagnosis and cardiovascular and vascular vulnerable plaque imaging.

The photoacoustic imaging system is a photoacoustic imaging system in which ultrasound array elements are densely arranged, that is, the array elements of the ultrasonic array of such systems are densely arranged. For example, the small animal photoacoustic imaging system developed by the group of Professor Lihong Wang of Washington University in St. Louis, the imaging probe can be made up of 512 ring-shaped detection devices made of 512 ultrasonic elements with a center frequency of 5 MHz, at the center of each two adjacent elements. The interval between the two is about 300 micrometers, the array elements are densely arranged, and the manufacturing process is very demanding, which makes the photoacoustic imaging system expensive. In addition, the system can be equipped with a 64-channel data acquisition card. In this case, it takes 8 times to complete the photoacoustic signal acquisition of an imaging section. In addition to the system delay, the imaging frame rate is only 0.625 Hz, and the data acquisition speed is not clinical. The need for rapid imaging. Another example is the curved photoacoustic tomography system developed by Professor Vasilis of the Technical University of Munich, Germany. The system can include an array of 256-element arc-shaped arrays covering 240 degrees, which can be used for small animal tomography and whole body imaging. The array element has a center frequency of 3.3 MHz and a single element size of 4 mm x 4 mm. The system light path can be used with a bundle of 10 branches to create a circular illumination of the imaging section to ensure relatively uniform illumination of the imaged area. The system is equipped with a linear stage to move the object to be imaged through the sample holder for three-dimensional scanning and imaging. The system can achieve an imaging frame rate of 10 Hz per second under multi-channel data acquisition equipment, which can basically meet the needs of clinical applications. However, multi-channel data acquisition devices are expensive. Therefore, the photoacoustic imaging system in which the ultrasound array elements are densely arranged has the sound and sound Such as low speed, high price and other shortcomings, and dense array of elements, making the array element size smaller, tissue deep signal detection sensitivity is low.

Photoacoustic imaging speed as a factor affecting the depth and breadth of clinical application of imaging technology. In the field of photoacoustic imaging applications (such as hemodynamics, oxygen metabolism, physiological state monitoring, etc.), high-speed photoacoustic imaging systems are needed to track and collect information reflecting the state of biological tissues in real time; clinical disease diagnosis applications Improve the data collection speed, reduce the time of the patient under the imaging device, and enable the doctor to obtain the disease information in real time and carry out targeted treatment in a timely manner. Photoacoustic computed tomography (PACT) based on ultrasonic array detection is a photoacoustic imaging method with rapid imaging potential. However, the PACT imaging system has a large number of array elements, large data volume, and data acquisition. High demands are placed on transmission and reconstruction, and imaging speeds in many applications still fall short of clinical real-time/fast imaging requirements.

In order to reduce the number of array elements used in imaging and achieve low-cost, fast data acquisition and imaging of large-area imaging, the team of Professor Huabei Jiang of the University of Florida has built a spherical, three-dimensional, sparse array photoacoustic imaging system. The ultrasonic detection part of the system is a self-made spherical detecting device. The device is designed with 640 holes, and 192 ultrasonic elements are arranged in three parts. Each ultrasonic element has an outer diameter of 5.5 mm and an effective detection area of 3 mm in diameter. The center frequency is 5 MHz, and each element has a signal receiving angle of 15 degrees. The system is illuminated at the top of the spherical device to form a uniform illumination area of approximately 2 square centimeters. In order to achieve fast data acquisition, a 64-channel data acquisition device (composed of eight 8-channel data acquisition cards) is configured. Under the multiplexed technology condition, a three-dimensional data acquisition speed of 0.3 frames per second and a two-dimensional imaging data acquisition rate of 10 Hz can be achieved. However, the system uses a sparse distribution pattern of the ultrasonic probe, and the signal receiving angle of the probe is very small, so the final imaging quality is not good enough. It can be seen that the sparse signal acquisition method can effectively reduce the data acquisition scale and reduce the design cost of the array, but the current image quality of the sparse signal acquisition photoacoustic imaging system is low, mainly because the traditional imaging method cannot achieve high under low signal acquisition amount. Quality image reconstruction.

It can be seen that there is currently no photoacoustic imaging system that combines fast imaging speed, low cost and good imaging quality.

Summary of the invention

The present disclosure proposes a dual-focus ultrasound probe and a sparse array photoacoustic tomography system, which can solve the problem of high cost, low imaging speed and low image acquisition quality of the photoacoustic imaging system.

In a first aspect, the dual focus ultrasound probe includes: a concave detection surface, the numerical aperture of the concave detection surface in the first direction is larger than the numerical aperture in the second direction, and the concave detection surface is in the first side The upward signal receiving angle is greater than the signal receiving angle in the second direction, and the length of the focusing region of the recess detecting surface in the second direction is greater than the length of the focusing region in the first direction, The first direction is perpendicular to the second direction.

Optionally, the recessed detecting surface is formed by bending a circular flat detecting surface by a first angle as a first axis of symmetry, and forming a second angle by symmetrically bending a second angle, wherein the first diameter is The second diameter is perpendicular, the first diameter is curved to form a first direction, and the second diameter is curved to form a second direction, the first angle being greater than the second angle.

Optionally, the length of the focus area of the recess detecting surface in the second direction is 50-80 times the length of the focus area in the first direction.

Optionally, the numerical aperture of the recess detecting surface along the first diameter direction is 7-9 times of the numerical aperture of the recess detecting surface along the second diameter direction.

Optionally, the probe is a cylinder, and the concave detecting surface is a bottom surface of the cylinder, and the cylinder has a diameter of 1-2 cm.

In the probe provided in this embodiment, since the numerical aperture of the recess detecting surface in the first direction is larger than the numerical aperture in the second direction, the signal receiving angle of the recess detecting surface in the first direction is greater than a signal receiving angle in the second direction, and a length of the focusing area of the recess detecting surface in the second direction is greater than a length of the focusing area in the first direction. In this case, the signal receiving angle of the concave detecting surface in the first direction is large, and also has a small virtual detecting point to form a strong focus. The length of the focus area in the second direction is large, forming a weak focus, which provides the ability to image a larger size section. When such a probe is applied to an imaging system, the image quality reconstructed by the low-sampling, virtual point detection-compression sensing image reconstruction method can be improved, and at the same time, since the signal receiving angle of the probe is large, the imaging system can adopt the sparse arrangement. The cloth pattern forms a circular array of probes, reducing the cost of the imaging system. Moreover, the large signal reception angle of the imaging section provided by the strong focus can reduce the amount of data acquisition required for high quality imaging, thereby improving data acquisition and imaging speed.

In a second aspect, the sparse array photoacoustic tomography system comprises: a pulse laser, a fiber coupler, a ring fiber array formed by a plurality of fiber branch arrangements of the fiber bundle, a ring probe array formed by the plurality of double focus ultrasound probes, and a data processing device connected to the plurality of dual focus ultrasound probes, wherein:

The pulsed laser is configured to emit a laser pulse;

The fiber optic coupler is configured to couple the laser pulse into the fiber bundle;

The annular fiber array is configured to emit an annular spot that illuminates a cross section of the biological tissue;

The annular probe array is configured to collect an ultrasonic signal emitted by the biological tissue section under the illumination of the annular optical fiber array;

The data processing apparatus is configured to perform image reconstruction using a virtual point detection-compression sensing image reconstruction method according to the ultrasound signal.

Optionally, the system may further include:

A lens group is arranged to collimate or adjust the optical path direction prior to coupling the laser pulse into the fiber bundle.

Optionally, the system may further include:

A drive motor configured to drive a plurality of dual focus ultrasound probes in the array of annular probes to move around the biological tissue section.

Optionally, the data processing device includes:

a data acquisition card, configured to acquire an ultrasonic signal collected by the annular probe array according to a preset frequency;

The processing module is connected to the data acquisition card and configured to perform image reconstruction according to the ultrasonic signal collected by the data acquisition card.

In the sparse array photoacoustic tomography system of the embodiment, the dual focus probe has a larger signal receiving angle and a smaller virtual detection point for the imaging section, thereby improving the reconstruction of the virtual point detection-compression sensing image reconstruction method. Image Quality. Since the dual-focus ultrasonic probe in the embodiment has a large signal receiving angle to the imaging section, the annular probe array can be formed in a sparse arrangement manner, and does not need to be densely distributed, that is, the number of probes required is small. In this way, the cost of the imaging system can be reduced. At the same time, the probe sparse arrangement allows the design of larger size ultrasound probes, which can improve the deep signal detection sensitivity of the tissue. At the same time, the amount of data acquisition required for image reconstruction can be reduced, thereby increasing the data acquisition speed and imaging speed, and advancing the depth and breadth of application of photoacoustic imaging technology in hemodynamics and clinical treatment of diseases.

DRAWINGS

The one or more embodiments are exemplified by the accompanying drawings in the accompanying drawings, and FIG. The figures in the drawings do not constitute a scale limitation unless otherwise stated.

Fig. 1A is a schematic side view showing the structure of a dual focus ultrasound probe in the present embodiment.

FIG. 1B is a schematic cross-sectional view of the probe structure shown in FIG. 1A.

1C is a side view showing the first recess of the probe structure shown in FIG. 1A.

FIG. 1D is a schematic side view showing the second groove of the probe structure illustrated in FIG. 1A.

Fig. 2 is a view showing a focus signal detecting area of the dual focus ultrasonic probe in the embodiment.

Fig. 3 is a view showing a focus signal detecting area of the dual focus ultrasonic probe in the first direction in the embodiment.

Fig. 4 is a view showing a focus signal detecting area of the dual focus ultrasonic probe in the second direction in the embodiment.

FIG. 5 is a schematic diagram showing virtual point detection and signal reception of the dual focus ultrasound probe in the first direction in the embodiment.

Fig. 6 is a view showing the structure of a sparse array photoacoustic tomography system in the present embodiment.

Fig. 7 is a schematic view showing the coaxial distribution of the annular fiber array and the probe array in this embodiment.

detailed description

The above described objects, features, and advantages of the present embodiments will be more clearly understood from the following description. It should be noted that, in the case of no conflict, the features in the optional embodiment and the embodiment may be combined with each other.

In the following description, numerous details are set forth in order to facilitate a full understanding of the embodiments, but the present disclosure may be practiced in other ways than those described herein, and thus the scope of the present disclosure is not limited by the following embodiments. limit.

In this embodiment, a dual focus ultrasound probe is provided. As shown in FIG. 1A, the probe includes a recessed detection surface 11 , and the numerical aperture of the recessed detection surface in the first direction 13 is larger than the numerical aperture in the second direction 12 . a signal receiving angle of the recess detecting surface in the first direction 13 is greater than a signal receiving angle in the second direction 12, and a length of the focusing area of the recess detecting surface 11 in the second direction 12 Greater than the length of the focus area in the first direction 13, the first direction 13 and the second direction are perpendicular to 12.

Since the numerical aperture of the recess detecting surface 11 in the first direction 13 is larger than the numerical aperture in the second direction 12, the signal receiving angle of the recess detecting surface 11 in the first direction 13 is greater than that in the second direction 12 The upper signal receiving angle and the length of the focusing area of the recess detecting surface 11 in the second direction 12 are greater than the length of the focusing area in the first direction 13. In this case, the signal receiving angle of the recessed detecting surface 11 in the first direction 13 is relatively large, and also has a small virtual detecting point, forming a strong focus. The length of the focus area in the second direction 12 is relatively large, forming a weak focus, which can provide the ability to image a larger size section. When such a probe is applied to an imaging system, the image quality reconstructed by the virtual point detection-compression sensing image reconstruction method can be improved. At the same time, because the signal receiving angle of the probe is large, the imaging system can form a circular probe array by sparse arrangement, thereby reducing the cost. In addition, sparsely arranged probe arrays allow the design of larger sized probes, Improve the deep signal detection sensitivity of the tissue, and, due to the large signal reception angle of the imaging section, the amount of data acquisition required for imaging is reduced, so that the imaging speed can be improved.

In implementation, the length of the focus area of the recessed detection surface 11 in the second direction 12 may be 50-80 times the length of the focus area in the first direction 13. It can be seen that the length of the focus area of the recessed detection surface 11 in the second direction 12 is much larger than the length of the focus area in the first direction 13, providing the ability to image a large-sized section.

In implementation, the probe may employ a cylinder, and the recessed detection surface is a bottom surface of the cylinder. Due to the sparse arrangement of the probe, it is allowed to design a probe of a larger size, for example, a probe having a diameter of 1 to 2 cm, thereby improving the deep signal detection sensitivity of the tissue.

In an embodiment, the recessed detecting surface may be formed by bending a circular flat detecting surface by a first angle as a symmetry axis and bending a first angle and symmetrically bending a second angle by a second diameter, the first diameter being The second diameter is vertical, the first diameter is curved to form a first direction 13, and the second diameter is curved to form a second direction 12, the first angle being greater than the second angle.

In implementation, the numerical aperture of the recess detecting surface along the first diameter direction may be 7-9 times the numerical aperture of the recess detecting surface along the second diameter direction.

1A is a schematic side view showing an optional probe, FIG. 1B is a schematic cross-sectional view of the probe structure shown in FIG. 1A, and FIG. 1C is a side view showing the first recess of the probe structure shown in FIG. 1A. FIG. 1D is a schematic side view showing the second groove of the probe structure illustrated in FIG. 1A. 1A-1D, the probe is a hollow cylindrical structure having a certain thickness. The probe has a circular cross section, and the annular inner wall has a diameter of 18 mm. Two first grooves 130 and two second grooves 120 are disposed on the sidewall of the detecting end of the probe. The two first grooves 130 are symmetrically disposed along the first direction 13 and the two second grooves 120 are disposed. Opposed in the second direction 12 oppositely. As shown in FIGS. 1C and 1D, the degree of depression of the first groove 130 is smaller than the degree of depression of the second groove 120. Optionally, the distance from the lowest point M of the first groove 130 to the bottom surface of the probe is H1, the distance from the lowest point N of the second groove 120 to the bottom surface of the probe is H2, and the height difference between H1 and H2 is about 4 mm. That is, the numerical aperture of the concave detection surface of the probe in the first direction 13 is greater than the numerical aperture in the second direction 12, optionally, the numerical aperture in the first direction 13 is different from the numerical aperture in the second direction 12. 8 times. Among them, the ultrasonic transducer is the probe, and the numerical aperture is a dimensionless parameter that can be used to measure the angular range of the light collected by the probe. In FIGS. 1A and 1B, the first direction 13 and the second direction 12 are indicated by broken lines. The dotted line area below the cylinder in FIG. 2 is the focus signal detection area of the probe. It can be seen that the signal detection angle of the focus detection in the first direction 13 is larger, about 9 times of the second direction 12, in the second direction. The signal reception angle on 12 is small, but the focal length is longer, about 64 times the first direction. In Figure 3, the dotted line is the first side of the probe. The range of focus signals on 13 is detected. In Figure 4, the dashed line is the focus signal detection range of the probe in the second direction 12. In the first direction 13, the numerical aperture is 0.8, the focal length is 11.25 mm, and the signal receiving angle is about 100 degrees, which is a strong focus. In the second direction 12, the numerical aperture is 0.1, the focal length is about 90 mm, and the signal reception angle is about 11.4 degrees, which is a weak focus. A schematic diagram of virtual point detection and signal reception of the probe in a first direction 13 is shown in FIG.

The height difference between the first groove and the second groove of the probe is caused by the difference in curvature between the first direction and the second direction, and the curvature can determine the depth of focus of the probe. When the focus of the probe needs to be designed, the first one can be increased. The difference in height between the groove and the second groove can reduce the difference in height between the first groove and the second groove when it is required to design the probe to be far away.

In this embodiment, a sparse array photoacoustic tomography system is further provided. As shown in FIGS. 6 and 7, the system includes a pulse laser, a fiber coupler, and a plurality of branch fiber bundles formed by the plurality of branches of the fiber bundle 2, and more An annular probe array formed by the above dual focus ultrasound probe 1 and a data processing device connected to the plurality of the dual focus ultrasound probes, wherein:

The pulsed laser is configured to emit a laser pulse;

Compressed sensing technology can be used in photoacoustic imaging systems based on sparse signal acquisition, which can show good reconstruction effects. However, the reconstruction performance of the compressed sensing technology and the minimum information sparsity required are closely related to the signal receiving angle of the probe, while the photoacoustic imaging system is generally an unfocused or unidirectional focusing ultrasonic detecting method, which cannot provide a sufficiently large signal receiving angle. May affect the performance of compression-sensing photoacoustic imaging. However, the probe designed in this embodiment has a large signal receiving angle to the imaging section, and thus the image quality reconstructed by the compressed sensing image reconstruction method can be improved. Since the dual-focus ultrasonic probe in the embodiment has a large signal receiving angle to the imaging section, the annular probe array can be formed in a sparse arrangement manner, and does not need to be densely distributed, that is, the number of probes required is small. In this way, the cost of the imaging system can be reduced. At the same time, the amount of data collection can be reduced, thereby increasing the data acquisition speed and imaging speed, and advancing the depth and breadth of application of photoacoustic imaging technology in hemodynamics and clinical treatment of diseases. Because of the sparse arrangement, each probe can be used in a larger size. Because the large-sized probe can improve the detection sensitivity of deep signals in biological tissues, it can Promote deep imaging capabilities and clinical application potential of photoacoustic tomography systems.

Since a plurality of dual-focus ultrasound probes form an annular probe array, ultrasonic signals emitted by biological tissues can be collected in an all-round and rapid manner. In this embodiment, in order to effectively distribute the light source in the reconstructed image region and improve the performance of the photoacoustic tomography, the circular probe array is used to collect the ultrasonic signal of the biological tissue section irradiated by the annular fiber array, that is, the optical and optical coaxial optical transmission is adopted. Harmony signal detection mode.

The workflow of the imaging system provided in this embodiment is roughly as follows:

The pulsed laser emits a laser pulse, and the fiber coupler couples the laser pulse into the fiber bundle, and the output end of each fiber branch in the annular fiber bundle emits laser light to form a relatively uniform annular illumination spot to be irradiated on the biological tissue section. The probe array collects the ultrasonic signals emitted by the irradiated biological tissue section, and the data processing device processes the collected signals to achieve fast/real-time imaging.

In practical applications, pulsed lasers can use high-energy OPO pulsed lasers with a pulse width of about 5-7 ns and a repetition rate of 10 Hz. In the near-infrared band, single-pulse energy can reach more than 10 MJ.

In an implementation, the imaging system provided in this embodiment may further include:

A lens group is arranged to collimate or adjust the optical path direction prior to coupling the laser pulse into the fiber bundle. Here, the laser energy coupled into the fiber bundle can be increased by collimating or adjusting the optical path direction before the laser pulse is coupled into the fiber bundle by the lens group.

Each of the dual focus ultrasound probes in the annular probe array needs to move along a circular trajectory as shown, so the imaging system provided in this embodiment may further include a drive motor for driving the annular probe array. A plurality of dual focused ultrasound probes move around the biological tissue section. Alternatively, the drive motor can be a stepper motor.

As shown in FIG. 6, in the imaging system provided in this embodiment, the data processing apparatus may include:

The processing module is connected to the data acquisition card and configured to perform image reconstruction according to the ultrasonic signal collected by the data acquisition card. The processing module here can use a high performance computer as shown in FIG. 6.

The data acquisition card can use a multi-channel high-speed data acquisition card.

This embodiment is based on an acoustic resolution, array photoacoustic imaging system, and is developed to solve the problem of high cost, high data set acquisition and low sampling rate high quality and rapid imaging. The system uses the virtual point detection-compression sensing method to reconstruct the photoacoustic image. To verify the effectiveness and superiority of the method in photoacoustic image reconstruction, the method has been applied to the acoustic resolution photoacoustic microscopy imaging system (acoutic- Resolution photoacoustic microscopy, AR-PAM), extends the imaging depth of the AR-PAM by reconstructing the out-of-focus area. Experimental results show that virtual points can provide greater signal connections The angle of convergence, combined with the theory of compressed sensing, can reduce the data acquisition rate and improve the quality of photoacoustic imaging.

In the present disclosure, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless specifically defined otherwise.

Industrial applicability

The present disclosure provides a dual focus ultrasound probe and a sparse array photoacoustic tomography system. The system can improve the image quality reconstructed by the compressed sensing image reconstruction method at a low sampling rate, and the annular probe array can be formed by using a sparse arrangement to reduce the cost of the imaging system. It also reduces the amount of data acquisition required for image reconstruction, which in turn increases data acquisition speed and imaging speed.

Claims

A dual focus ultrasound probe comprising:

a concave detecting surface, the numerical aperture of the concave detecting surface in the first direction is larger than the numerical aperture in the second direction, so that the signal receiving angle of the concave detecting surface in the first direction is greater than in the second direction a signal receiving angle, and a length of the focusing area of the recess detecting surface in the second direction is greater than a length of the focusing area in the first direction, the first direction being perpendicular to the second direction.
The probe according to claim 1, wherein the concave detecting surface is configured to bend the circular flat detecting surface by a first angle symmetrical about a first axis and to bend the second angle symmetrically with the second diameter thereof. Forming, the first diameter is perpendicular to the second diameter, the first diameter is curved to form a first direction, and the second diameter is curved to form a second direction, the first angle is greater than the second angle .
The probe according to claim 1, wherein a length of the focus area of the recess detecting surface in the second direction is 50-80 times a length of the focus area in the first direction.
The probe according to claim 1, wherein a numerical aperture of the recess detecting surface along the first diameter direction is 7-9 times a numerical aperture of the recess detecting surface along the second diameter direction.
The probe according to any one of claims 1 to 4, wherein the probe is a cylinder, and the recess detecting surface is a bottom surface of the cylinder, and the cylinder has a diameter of 1 to 2 cm.
A sparse array photoacoustic tomography system comprising: a pulsed laser, a fiber coupler, an annular fiber array formed by a plurality of branches of the fiber bundle, and a plurality of dual focus ultrasound probes according to any one of claims 1-5 An annular probe array formed and a data processing device coupled to the dual focus ultrasound probe, wherein:

The pulsed laser is configured to emit a laser pulse;

The fiber optic coupler is configured to couple the laser pulse into the fiber bundle;

The annular fiber array is configured to emit an annular spot that illuminates a cross section of the biological tissue;

The annular probe array is configured to acquire an ultrasonic signal emitted by the biological tissue section under illumination of the annular fiber array;

The data processing apparatus is configured to perform image reconstruction using a virtual point detection-compression sensing image reconstruction method according to the ultrasound signal.
The system of claim 6 further comprising:

A lens group is arranged to collimate or adjust the optical path direction prior to coupling the laser pulse into the fiber bundle.
The system of claim 6 further comprising:

a drive motor configured to drive a plurality of dual focus ultrasound probes in the array of annular probes around said Biological tissue section movement.
The system of claim 6 wherein said data processing device comprises:

a data acquisition card, configured to acquire an ultrasonic signal collected by the annular probe array according to a preset frequency;

The processing module is connected to the data acquisition card and configured to perform image reconstruction according to the ultrasonic signal collected by the data acquisition card.