A dynamic image filtering method for cone-beam breast CT imaging

Abstract

The present invention discloses a dynamic image filtering method for cone beam breast CT imaging, including installation of a filter plate motion device, setting of a dynamic control system, and image reconstruction preprocessing. The advantages of the present invention over the prior art are: the present invention proposes a dynamic filter device and method for compensating for image consistency problems caused by breast morphology, which is achieved through steps such as installation of a filter plate motion device, setting of a dynamic control system, and image reconstruction preprocessing, thereby simplifying the diagnosis process, reducing the difficulty of diagnosis, and improving the accuracy of diagnosis.

Description

Technical Field

[0001] The present invention relates to cone-beam breast CT (Cone-Beam Breast CT, CBBCT) images, and is used to compensate for the image consistency problem caused by breast morphology. Background Art

[0002] In 2020, the latest data from the World Health Organization showed that breast cancer has surpassed lung cancer to become the cancer with the highest incidence rate among all cancers, and also the cancer with the highest mortality rate among women. In 2020, the incidence rate of breast cancer in Chinese women was 59.0 / 100,000, ranking first in the national incidence spectrum of female malignant tumors. According to data released by the National Cancer Center, there were 304,000 new cases of breast cancer in Chinese women in 2015, accounting for 17.1% of the number of new cases of malignant tumors in women. There is currently no effective way to prevent and control the occurrence of breast cancer. If breast cancer is diagnosed and treated early, the 5-year survival rate can be as high as 99%. The low survival rate of breast cancer in underdeveloped areas is generally believed to be due to the lack of effective early detection methods and screening systems, resulting in a large number of women being in the late stage when breast cancer is discovered, missing the best treatment time and treatment methods. Early screening and early diagnosis are still the most important ways to improve the survival rate of breast cancer and prolong survival time.

[0003] Breast imaging methods are the main means of early detection of breast cancer. The commonly used breast imaging method using X-rays is mammography. Mammography has the advantages of good imaging effect and low cost, and has been proven to effectively reduce breast cancer mortality in long-term application. Therefore, mammography is recommended as the main breast cancer screening method for women at general risk. However, as a two-dimensional imaging method, mammography takes projected images by squeezing the breast, which leads to overlapping of breast tissue, not only poor patient experience, but also greatly reduces the imaging effect for dense and small breasts commonly found in Oriental women. Studies have shown that for dense breasts, the sensitivity of mammography is less than 40%.

[0004] The Cone Beam Breast CT (CBBCT) system is a three-dimensional breast imaging technology based on cone beam X-rays and high-speed flat-panel detector technology. It is currently the only commercial breast CT system in the world. Since its launch and obtaining the registration certificate from the State Food and Drug Administration, the system has been applied in the field of breast imaging with its true three-dimensional, high resolution, and no tissue overlap. It has shown its superiority over existing mammography imaging in all aspects. At present, the application of CBBCT in breast cancer diagnosis has accumulated a lot of experience and data.

[0005] In CBBCT scanning, the breast does not need to be squeezed vigorously, but scanned in a naturally drooping state to improve the patient's comfort. Due to the influence of the breast's outer contour in the natural state, when X-rays pass through the breast, the penetration of X-ray photons in the larger breast diameter is less than that in the smaller breast diameter. The imaging on the flat-panel detector will also have a large density difference, which will bring problems such as image quality consistency and artifacts. Summary of the invention

[0006] The technical problem to be solved by the present invention is that under the existing technology, the pixel CT values ​​of the same tissue at different positions in the CBBCT image are different, which brings certain difficulties to the diagnosis.

[0007] In order to solve the above technical problems, the present invention provides a technical solution: a dynamic image filtering method for cone beam breast CT imaging, comprising the following steps:

[0008] Step 1: Install the filter plate motion device. The filter plate 1 is installed on a moving platform composed of an X-axis linear slide 7, a Z-axis linear slide 8, and a Y-axis linear slide 9. The X-axis linear slide 7, the Z-axis linear slide 8, and the Y-axis linear slide 9 respectively control the spatial movement of the filter plate 1 on the X, Y, and Z axes. The filter and the slide are fixed on the tube fixing frame 10 and rotate with the rotation of the device. For breasts of different shapes or different shapes of breasts at different exposure angles, the three-dimensional position of the filter plate 1 is adjusted to form the best match with the specific breast shape.

[0009] Step 2: Set up a dynamic control system. When the device rotates 360° along the central axis of rotation for scanning, the control system estimates the optimal filter position based on the current breast projection image, and controls the X-axis linear slide 7, the Z-axis linear slide 8, and the Y-axis linear slide 9 to move to the corresponding position. As the scanning angle changes, the control system continuously monitors the breast morphology and adjusts the position of the filter plate 1 according to the difference until the scanning is completed.

[0010] Step 3: Image reconstruction preprocessing: the collected projection image is restored according to the position of the filter plate 1, and the projection image is restored to the situation without the filter plate 1. The restored projection image can be reconstructed into a normal three-dimensional image.

[0011] The advantages of the present invention over the prior art are as follows: the present invention proposes a dynamic filter device and method for compensating for the image consistency problem caused by breast morphology, which is achieved through the steps of installing a filter plate motion device, setting a dynamic control system, and image reconstruction preprocessing, thereby simplifying the diagnosis process, reducing the difficulty of diagnosis, and improving the accuracy of diagnosis.

[0012] Furthermore, the filter plate 1 is a plate structure that is close to the shape of the breast. The material of the filter plate 1 is aluminum or other suitable materials. Its thickness distribution is consistent with the general standard breast shape and thickness to compensate for the intensity difference of the X-ray, so that the intensity of the X-ray beam 3 that finally reaches the detector 2 is relatively consistent. The filter plate 1 has a consistent density, a smooth shape and surface, and does not bring about image artifacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention is a structural schematic diagram of a filter plate of a dynamic image filtering method for cone-beam breast CT imaging.

[0014] Figure 2 The present invention is a schematic diagram of the device structure of a dynamic image filtering method for cone-beam breast CT imaging.

[0015] As shown in the figure: 1. filter plate, 2. detector, 3. X-beam, 4. rotating center axis, 5. breast, 6. tube, 7. X-axis linear slide, 8. Z-axis linear slide, 9. Y-axis linear slide, 10. tube fixing frame. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0017] When the present invention is specifically implemented, Figure 1 and Figure 2 In the embodiment shown, a dynamic filter device and method are proposed to compensate for the image consistency problem caused by breast morphology. The dynamic filter device and method include four components:

[0018] 1) Breast morphology filter. The filter is made of aluminum or other suitable materials, and its thickness distribution is consistent with the general standard breast morphology and thickness to compensate for the intensity difference of X-rays, so that the X-ray intensity reaching the detector is relatively consistent. The filter has a uniform density, smooth shape and surface, and does not bring image artifacts.

[0019] 2) Filter plate movement device. The filter plate is installed on a moving platform composed of three sets of linear slides, X, Y, and Z. The three sets of slides control the spatial movement of the filter plate on the X, Y, and Z axes respectively. The filter and slide are fixed on the tube fixing frame and rotate with the rotation of the equipment. For different shapes of breasts, or different shapes of breasts at different exposure angles, the three-dimensional position of the filter plate is adjusted to form the best match with the specific breast shape.

[0020] 3) Dynamic control system. When the device rotates 360° along the central axis, the control system estimates the optimal filter position based on the current breast projection image and controls the X, Y, and Z slides to move to the corresponding position. As the scanning angle changes, the control system continuously monitors the breast morphology and adjusts the filter plate position according to the difference until the scan is completed.

[0021] 4) Image reconstruction preprocessing. The collected projection image is restored according to the position of the filter plate, and the projection image is restored to the situation without the filter plate. The restored projection image can be reconstructed into a normal three-dimensional image.

[0022] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A dynamic image filtering method for cone-beam breast CT imaging, Features The following steps are involved: Step 1: Installing the filter plate motion device, the filter plate (1) is installed on a moving platform composed of an X-axis linear slide (7), a Z-axis linear slide (8), and a Y-axis linear slide (9), wherein the X-axis linear slide (7), the Z-axis linear slide (8), and the Y-axis linear slide (9) respectively control the spatial movement of the filter plate (1) along the X, Y, and Z axes, and the filter plate (1) and the slide are fixed on a tube fixing frame (10) and rotate along with the rotation of the device, wherein the filter plate (1) is a plate structure close to the breast shape, and its thickness distribution is consistent with the thickness of a general standard breast shape; Step 2: Setting a dynamic control system. When the device rotates 360° along the central axis of rotation for scanning, the control system estimates the optimal position of the filter plate (1) based on the current breast projection image, and controls the X-axis linear slide (7), the Z-axis linear slide (8), and the Y-axis linear slide (9) to move to the corresponding position. As the scanning angle changes, the control system continuously monitors the breast morphology and adjusts the position of the filter plate (1) according to the difference until the scanning is completed. Step three, image reconstruction preprocessing, the collected projection image is subjected to image restoration processing according to the position of the filter plate (1), the projection image is restored to the situation without the filter plate (1), and the restored projection image can be used for normal three-dimensional image reconstruction.

2. A dynamic image filtering method for cone-beam breast CT imaging according to claim 1, Features The filter plate (1) is made of aluminum or other suitable materials, and its thickness distribution is consistent with the thickness of the general standard breast shape to compensate for the intensity difference of the X-ray, so that the intensity of the X-ray beam (3) finally reaching the detector (2) is relatively consistent. The filter plate (1) has a consistent density, a smooth shape and a smooth surface, and does not cause image artifacts.

Images