An ultrasonic CT phased-array method based on a ring array

Abstract

The application belongs to the technical field of ultrasonic imaging, and particularly relates to an ultrasonic CT phased array method based on a ring array, wherein the ultrasonic CT adopts a ring array sensor, including N ring-arranged array elements, and the excitation pulses of each array element are delayed and emitted according to the characteristics of the required ultrasonic beam in terms of delay time; during reception, the echo signals received by each array element are compensated in terms of delay according to the delay time during emission, and then coherent superposition is performed to realize beam forming. The application combines the advantages of the ring array, the ultrasonic CT technology and the phased array principle, combines the ultrasonic CT phased array principle based on the ring array, constructs the ultrasonic CT phased array method based on the ring array, and effectively improves the shortcomings of inaccurate ultrasonic detection, low imaging resolution and limited application field range.

Description

Technical Field

[0001] This invention belongs to the field of ultrasound imaging technology, specifically relating to an ultrasound CT phased array method based on a ring array. Background Technology

[0002] Ultrasound CT refers to the measurement of the projection data of an object under ultrasonic wave irradiation using an array of ultrasonic transducers without damaging the internal structure of the target body. This data can then be used to reconstruct two-dimensional or three-dimensional ultrasound images. It offers advantages such as tomographic imaging, high resolution, and flexible combinations of various imaging modes, demonstrating significant advantages in early screening in clinical medicine and non-destructive testing of materials. Therefore, using ultrasound as the emission source to replace X-ray irradiation of the target body has gradually become one of the new goals pursued by researchers in the field of ultrasound applications.

[0003] Phased array technology, with its flexible beam deflection and focusing capabilities, offers significant advantages over traditional ultrasonic testing in defect location and accuracy detection. Phased array ultrasonic transmission is based on the Huygens-Fresnel principle. When each array element is excited by pulses of the same frequency, the emitted ultrasonic waves interfere to form a composite wavefront, thus creating a stable ultrasonic field in space. If the excitation pulse times of each element are changed, causing them to emit with a certain delay, then according to Huygens' principle, the emitted ultrasonic waves will superimpose in space to synthesize a new wavefront, thereby achieving beam deflection or focusing. Based on the reciprocity principle, phased array reception also uses a delay method. The received information from each element is compensated for the delay based on the time difference of the echo arrival at each element, and then superimposed to obtain the reflected echo in a certain target direction, thereby obtaining data information about the medium or defect.

[0004] Currently, common linear array-based ultrasonic phased arrays are mainly used in medical ultrasound imaging, industrial non-destructive testing, oil well logging imaging, and high-temperature tumor treatment. However, for objects with arc-shaped or ring-shaped structures, linear array-based ultrasonic phased arrays do not fit snugly enough during detection. Moving the array causes signal loss in the gaps between the imaging planes, significantly limiting invasive detection capabilities due to planar acoustic imaging. Furthermore, the lateral resolution of the imaging is significantly lower than the axial resolution due to the target's position, resulting in poor detection quality. Summary of the Invention

[0005] The present invention overcomes the shortcomings of the existing technology and the technical problem to be solved is: to provide an ultrasound CT phased array method based on a ring array, so as to effectively improve the shortcomings of inaccurate ultrasound diagnosis and low imaging resolution.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a phased array ultrasound CT method based on a ring array, wherein the ultrasound CT uses a ring array sensor, including... The array consists of a ring of array elements, and the excitation pulse of each array element is delayed according to the characteristics of the ultrasonic beam required.

[0007] When focusing the ultrasonic beam transmitted by the ring array is required, the delay time of each element in the ring array is:

[0008] when When it is an odd number,

[0009] ;

[0010] when When it is even,

[0011] ;

[0012] in, Indicates the first time when the ring array is focused The delay time of each array element Indicates focal length. Represents the radius of curvature of the ring array. Indicates the center distance of the array elements. This indicates the speed of sound of ultrasound in a medium. This represents the time constant.

[0013] When the ultrasonic beam transmitted by the ring array needs to be deflected, the delay time of each element in the ring array is:

[0014] when When it is an odd number,

[0015] ;

[0016] when When it is even,

[0017] ;

[0018] Indicates the first time when the ring array deflects. The delay time of each array element Indicates the deflection angle.

[0019] When the ultrasonic beam transmitted by the ring array needs to be focused and deflected, the delay time of each element in the ring array is:

[0020] when When it is an odd number,

[0021]

[0022] when When it is even,

[0023]

[0024] Indicates the first time when the ring array is focused and deflected. The delay time of each array element.

[0025] The aforementioned phased array method for ultrasound CT based on a ring array performs delay compensation on the echo signals received by each array element according to the delay time during transmission, and then performs coherent superposition to achieve beamforming.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] This invention provides an ultrasonic phased array method for CT based on a ring array, which can obtain echo data information of the object under test from all directions by controlling beamforming. At the same time, the ultrasonic phased array can flexibly, conveniently and effectively control the beam shape, effectively improving the shortcomings of ultrasonic detection such as inaccuracy, low imaging resolution and limited application range, and greatly improving the detection efficiency. Attached Figure Description

[0028] Figure 1 A schematic diagram illustrating the principle of a phased array ultrasound CT method based on a ring array, provided in an embodiment of the present invention;

[0029] Figure 2 The images show the beamforming acoustic field of a phased array ultrasound CT method based on a ring array. The first row shows the ring array beam focusing acoustic field, with focal lengths of 50mm, 100mm, and 150mm from left to right. The second row shows the ring array beam deflection acoustic field, with deflection angles of -10°, 0°, and 10° from left to right. The third row shows the ring array beam focusing deflection acoustic field, with focal lengths of 50.77mm, 115.47mm, and 173.21mm from left to right, corresponding to deflection angles of 10°, 30°, and -30°. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides a phased-array ultrasound CT method based on a ring array. During transmission, the excitation pulses of each element of the ring array are emitted with different delay times, causing the emitted ultrasound waves to superimpose and form a new wavefront. This results in a focused and deflected ultrasound beam. Simultaneously, during reception, the ultrasound signals received by each element are delayed based on the time difference of their arrival at each element, and then coherently superimposed to enhance the echo signal in a specific direction (region of interest, such as a defect or tumor) while weakening or even canceling echo signals in other directions, thereby further improving the system's detection sensitivity.

[0032] like Figure 1 As shown in this embodiment, during transmission, the basic principle of the ultrasonic CT phased array method based on a ring array is to excite each array element sequentially with a relative delay when transmitting sound waves, with the center of the ring array as the reference point. Using [reference point], the ultrasonic waves emitted by each element of the ring array are positioned at a focal length of [focal length]. The focus Focusing is achieved at the point where the center element (element 1) is located, or at the angle between the line connecting the center element and the center of the circle. It achieves focusing and deflection.

[0033] For by A circular array composed of n array elements, the nth The relative delay time of each array element can be obtained through focusing or deflection principles.

[0034] The beam control principle of ultrasound CT based on ring array includes:

[0035] (1)

[0036] (2)

[0037] in, Indicates the sound path difference, This indicates the speed of sound of ultrasound in a medium. Indicates the first The relative delay time of each array element. As the focus, and Indicates two different array elements to the focal point The line segment.

[0038] Therefore, according to spatial geometric relations, when If the number is odd, then we have:

[0039] (3)

[0040] when When it is even,

[0041] (4)

[0042] in, Indicates the first time when the ring array is focused The delay time of each array element Indicates focal length. Represents the radius of curvature of the ring array. Indicates the center distance of the array elements. This indicates the speed of sound of ultrasound in a medium. This represents the time constant.

[0043] Based on the emission deflection principle of ultrasound CT using a ring array, it can be derived that when... When the number is odd, then we have:

[0044] (5)

[0045] when When it is even,

[0046] (6)

[0047] Indicates the first time when the ring array deflects. The delay time of each array element Indicates the deflection angle.

[0048] The principle of focused acoustic beam deflection in ultrasound CT based on a ring array can be derived as follows: when When the number is odd, we have:

[0049] (5)

[0050] when When it is even,

[0051] (6)

[0052] in, Indicates the first time when the ring array is focused and deflected. The delay time of each array element.

[0053] During reception, delay compensation is performed on the echo signals received by each array element based on the delay time during transmission, and then coherent superposition is performed to achieve beamforming.

[0054] like Figure 2The image shows a beamforming acoustic field obtained using a ring array-based phased array method for ultrasound CT according to an embodiment of the present invention. The ring array has 128 elements, a radius of 100 mm, and an acoustic frequency of 1 MHz. The first row shows the ring array beam focusing acoustic field, with focal lengths from left to right of 50 mm, 100 mm, and 150 mm. The second row shows the ring array beam deflection acoustic field, with deflection angles from left to right of -10°, 0°, and 10°. The third row shows the ring array beam focusing deflection acoustic field, with focal lengths from left to right of 50.77 mm, 115.47 mm, and 173.21 mm, corresponding to deflection angles of 10°, 30°, and -30°. Therefore, the phased array method of the present invention can achieve ultrasound polarization and focusing.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phased array ultrasound CT method based on a ring array, characterized in that, Ultrasound CT uses a ring array sensor, including The array consists of a ring of array elements, and the excitation pulse of each array element is delayed according to the characteristics of the ultrasonic beam required. When focusing the ultrasonic beam transmitted by the ring array is required, the delay time of each element in the ring array is: when When it is an odd number, ； when When it is even, ； in, Indicates the first time when the ring array is focused The delay time of each array element Indicates focal length. Represents the radius of curvature of the ring array. Indicates the center distance of the array elements. This indicates the speed of sound of ultrasound in a medium. This represents the time constant.

2. The ultrasound CT phased array method based on a ring array according to claim 1, characterized in that, When the ultrasonic beam transmitted by the ring array needs to be deflected, the delay time of each element in the ring array is: when When it is an odd number, ； when When it is even, ； Indicates the first time when the ring array deflects. The delay time of each array element Indicates the deflection angle.

3. The ultrasound CT phased array method based on a ring array according to claim 1, characterized in that, When the ultrasonic beam transmitted by the ring array needs to be focused and deflected, the delay time of each element in the ring array is: when When it is an odd number, when When it is even, Indicates the first time when the ring array is focused and deflected. The delay time of each array element.

4. The ultrasound CT phased array method based on a ring array according to claim 1, characterized in that, During reception, delay compensation is performed on the echo signals received by each array element based on the delay time during transmission, and then coherent superposition is performed to achieve beamforming.

Images