A fast imaging method for breast positioning in a hemispherical ultrasound tomography system

Abstract

The present invention belongs to the field of ultrasonic tomography, and specifically relates to a rapid imaging method for breast positioning in a hemispherical ultrasonic tomography system, including: air-water data acquisition; breast data acquisition; parsing the acquired data; preprocessing the parsed data; calculating the attenuation coefficient; image reconstruction; processing the reconstructed image, storing the processed image in a designated memory location, and periodically reading it through a GUI end; displaying the breast position images of the coronal plane and the sagittal plane through the GUI end to judge whether the patient's breast position is in the optimal area. The present invention can image a pair of coronal plane and a pair of sagittal plane acoustic attenuation rate maps in real time, and can judge whether the breast is in the optimal imaging area in the XY direction through the coronal plane, and can judge whether the patient's prone position is deep enough in the Z direction through the sagittal plane. The present invention is integrated in the GUI operation interface, and the image is displayed in the GUI in real time, which is convenient for operation and judgment of whether the patient's breast position is in the optimal area.

Description

Technical Field

[0001] The invention belongs to the field of ultrasonic tomography, and in particular relates to a rapid imaging method for breast positioning in a hemispherical ultrasonic tomography system. Background Art

[0002] The imaging space of ultrasound tomography is three-dimensional, but the optimal imaging area is generally smaller than the imaging aperture size. When the patient lies prone on the device, the naked eye cannot judge whether the breast is in the optimal imaging area. The existing optical camera method cannot accurately determine the position of the patient's breast and the imaging effect varies greatly.

[0003] A Chinese patent with publication number CN113598825A discloses a breast positioning imaging method for an ultrasonic imaging system and its application. The scheme includes the following steps: setting a sequence of ultrasonic transducer array elements, each of which transmits and collects ultrasonic signals according to the sequence; calculating and obtaining the contour of a coronal plane of the breast based on the collected ultrasonic signals; performing spatial coordinate transformation on the contour to obtain the spatial distribution of the contour in the cross section of the ultrasonic imaging system. The present invention has the advantages of high positioning accuracy and good imaging effect.

[0004] However, the above breast positioning imaging method still has the following disadvantages:

[0005] The contrast is poor, the noise is obvious, it is difficult to effectively identify the position of the breast, and there is only one cross-section display (X, Y direction) without depth information. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, the present invention provides a technical solution of a rapid imaging method for breast positioning in a hemispherical ultrasonic tomography system.

[0007] A rapid imaging method for breast positioning in a hemispherical ultrasonic tomography system, comprising:

[0008] Step 1, air and water data collection;

[0009] Step 2, breast data collection;

[0010] Step 3, analyzing the collected data;

[0011] Step 4, preprocessing the parsed data;

[0012] Step 5, calculating the attenuation coefficient;

[0013] Step 6, performing image reconstruction;

[0014] Step 7, the reconstructed image is processed, and the processed image is stored in a specified memory location and periodically read through the GUI end.

[0015] Furthermore, in step 1 and step 2, each time data is collected, data of the coronal plane and data of the sagittal plane are collected simultaneously.

[0016] Furthermore, the step 3 comprises:

[0017] The transmitting TAS number, the transmitting array element number, the receiving TAS number, the receiving array element number and a segment of AScan are matched and stored in the memory.

[0018] Furthermore, the step 3 includes: distinguishing sagittal plane data from coronal plane data, and using them for reconstruction of sagittal plane and coronal plane images respectively.

[0019] Furthermore, the step 4 comprises:

[0020] Step 4.1, calculate the energy of each segment of AScan signal according to the following formula:

[0021]

[0022] Where L is the characteristic length of the transmitted signal, and t0 is the arrival time of the direct wave;

[0023] Step 4.2, LOR sorting, includes: connecting all pairs of transmitting array elements and receiving array elements, calculating the result of polar coordinate transformation of the Line in the original rectangular coordinate system, arranging the signal into a (R, theta) matrix, where R is the distance from the path to the center point, and theta is the angle between the path and the coordinate axis. The data in the sagittal and coronal planes are sorted separately for LOR.

[0024] Furthermore, the step 5 comprises:

[0025] According to the energy I calculated in step 4, the sorted empty water and breast data are calculated according to the following formula:

[0026] Atten = log(I 空水 / I 物体 )

[0027] Where Atten is the attenuation coefficient of each transmitting and receiving pair.

[0028] Further, the step 6 comprises:

[0029] Reconstruct the processed Atten according to the following formula:

[0030]

[0031]

[0032]

[0033] Where f is the image, k is the number of iterations, n is the pixel number, and w mn is the intersection distance between the mth attenuation and the nth pixel, p m is the mth attenuation value, is the attenuation value of the mth weighted projection, W m+ is the normalization factor corresponding to the mth attenuation, λ k is the coefficient of the kth iteration, is the sampling point of the entire imaging system, w m’n It is the sum of the distances between pixel n and all attenuation intersections. m' is used to calculate the sum of the distances between pixel n and all attenuation intersections. It is a constant weight and can be removed.

[0034] Furthermore, the step 7 comprises:

[0035] Step 7.1, mapping the reconstructed image value to the range of 0 to 255;

[0036] Step 7.2, according to the theoretical optimal imaging area, add a rectangular frame mask to the sagittal and coronal plane reconstructed images respectively, retain the image within the mask, and set the image outside the mask to 0. The processed image is stored in the specified memory location and periodically read through the GUI end.

[0037] Furthermore, step 8 includes: the GUI terminal displays the breast position images of the coronal plane and the sagittal plane respectively through two windows to determine whether the patient's breast position is in the optimal area.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention can image a pair of coronal and sagittal acoustic attenuation rate maps in real time. The coronal plane can be used to determine whether the breast is in the optimal imaging area in the XY direction, and the sagittal plane can be used to determine whether the patient's prone position is deep enough in the Z direction. The present invention is integrated into a GUI operation interface, and images are displayed in the GUI in real time, which is convenient for operation and for determining whether the patient's breast position is in the optimal area. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings.

[0042] The hemispherical bracket used in the present invention refers to patent CN113598825A, and the ultrasonic transducer array and ultrasonic transducer array elements of the present invention are numbered according to the method in patent CN113598825A.

[0043] See also Figure 1 , a rapid imaging method for breast positioning of a hemispherical ultrasound tomography system, comprising the following steps:

[0044] Step 1: Air and water data collection

[0045] Empty-water data collection is data collection when there is only water but no objects, and its function is to provide a benchmark for the present invention.

[0046] The selection of the transmitting and receiving transducers follows the principle of geometric spatial position: the TAS at the intersection of the cut plane and the hemispherical transducer is selected. Each time the data is collected, the coronal and sagittal planes are collected simultaneously.

[0047] Step 2: Breast data collection

[0048] The breast data is collected using the same ultrasonic transducer and collection method as above.

[0049] Step 3: Data analysis

[0050] The main purpose is to match the transmit TAS number, transmit array element number, receive TAS number, receive array element number and a segment of AScan (4000 points) and save them in memory. At the same time, this step distinguishes the sagittal plane from the coronal plane, which are used for the reconstruction of sagittal and coronal images respectively.

[0051] Step 4: Data preprocessing

[0052] Step 4.1, calculate the energy of each segment of AScan signal and integrate it according to the following formula:

[0053]

[0054] Where L is the characteristic length of the transmitted signal and t0 is the arrival time of the direct wave.

[0055] Step 4.2, reorder the LOR (Line of Response). The specific method is to reorder the signals according to their geometric positions. Connect all pairs of transmitting array elements and receiving array elements, calculate the polar coordinate transformation of the Line in the original direct coordinate system, and arrange the signals into a (R, theta) matrix. R is the distance from the path to the center point, and theta is the angle between the path and the coordinate axis. In this step, the sagittal and coronal data need to be sorted separately for LOR.

[0056] Step 5: Calculate the attenuation coefficient

[0057] According to the energy I calculated in step 4, the sorted empty water and breast data are calculated according to the following formula:

[0058] Atten = log(I 水 / I 物体 )

[0059] Atten is the attenuation coefficient of each transmit-receive pair.

[0060] Step 6: Image reconstruction

[0061] The processed Atten is reconstructed according to the following formula.

[0062]

[0063]

[0064]

[0065] Where f is the image, k is the number of iterations, n is the pixel number, and w mn is the intersection distance between the mth attenuation and the nth pixel, p m is the mth attenuation value, is the attenuation value of the mth weighted projection, W m+ is the normalization factor corresponding to the mth attenuation, λ k is the coefficient of the kth iteration, is the sampling point of the entire imaging system, and m' is used to calculate the sum of pixel n and all attenuation intersection distances. It is a constant weight and can be removed.

[0066] Step 7: Image processing

[0067] Step 7.1, map the reconstructed image value to the range of 0 to 255.

[0068] Step 7.2, according to the theoretical optimal imaging area, add a rectangular frame mask to the sagittal and coronal reconstructed images respectively. The mask is a two-dimensional matrix with 1 inside the optimal area and 0 outside. The image inside the mask is retained, and the image outside is set to 0. The processed image will be stored in the specified memory location and read periodically by the GUI end.

[0069] Step 8, Image GUI display

[0070] The GUI (Graphical User Interface) has two windows that display the breast position images in the coronal plane and sagittal plane respectively, to determine whether the patient's breast position is in the optimal area. If the breast is not in the optimal imaging area, the patient is guided to move and adjust the breast position until the breast is in the optimal area.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 rapid imaging method for breast positioning in a hemispherical ultrasonic tomography system, characterized in that: include: Step 1: empty and water data collection. Each time the data is collected, the coronal and sagittal data are collected simultaneously. Step 2: Breast data collection. Each time the data is collected, the coronal and sagittal data are collected simultaneously. Step 3: Analyze the collected data, including: Match the transmitting TAS number, transmitting array element number, receiving TAS number, receiving array element number and a segment of AScan, save them in the memory, distinguish the sagittal plane data from the coronal plane data, and use them for the reconstruction of sagittal plane and coronal plane images respectively; Step 4: preprocess the parsed data, including: Step 4.1, calculate the energy of each AScan signal according to the following formula: Where L is the characteristic length of the transmitted signal, and t0 is the arrival time of the direct wave; Step 4.2, LOR sorting, includes: connecting all pairs of transmitting array elements and receiving array elements, calculating the result of polar coordinate transformation of the connection line in the original rectangular coordinate system, arranging the signal into a (R, theta) matrix, where R is the distance from the path to the center point, and theta is the angle between the path and the coordinate axis, wherein the sagittal and coronal data are separately sorted for LOR; Step 5, calculating the attenuation coefficient, includes: According to the energy I calculated in step 4, the sorted empty water and breast data are calculated according to the following formula: Atten=log(I 空水 / I 物体 ) Where Atten is the attenuation coefficient of each transmitting and receiving pair; Step 6, performing image reconstruction, including: Reconstruct the processed Atten according to the following formula: Where f is the image, k is the number of iterations, n is the pixel number, and w mn is the intersection distance between the mth attenuation and the nth pixel, p m is the mth attenuation value, is the attenuation value of the mth weighted projection, W m+ is the normalization factor corresponding to the mth attenuation, λ k is the coefficient of the kth iteration, is the sampling point of the entire imaging system, w m’n is the sum of the distances between pixel n and all attenuation intersections, m' is used to calculate the sum of the distances between pixel n and all attenuation intersections, and is a constant weighted; Step 7, processing the reconstructed image, and storing the processed image in a specified memory location, including: Step 7.1, mapping the reconstructed image value to the range of 0 to 255; Step 7.2, according to the theoretical optimal imaging area, add a rectangular frame mask to the sagittal and coronal plane reconstructed images respectively, retain the image within the mask, and set the image outside the mask to 0. The processed image is stored in the specified memory location and periodically read through the GUI end.

2. The rapid imaging method for breast positioning of a hemispherical ultrasonic tomography system according to claim 1, characterized in that: The method further includes step 8, which includes: the GUI terminal displays the breast position images of the coronal plane and the sagittal plane respectively through two windows to determine whether the patient's breast position is in the optimal area.

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