SPECT / CT based 99m Methods for determining the attenuation coefficient of Tc, methods for calculating GFR value, and systems

Abstract

This invention discloses a SPECT / CT-based method 99m The method and system for determining the attenuation coefficient of Tc and calculating the GFR value include measuring the distance from the first and second sides of the body surface to the center of the target tissue, and calculating the first and second depths from the body surface to the center of the target tissue; and performing [treatment] on the target tissue. 99m SPECT dynamic imaging of Tc simultaneously acquires the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface; the radioactivity count is calculated and measured based on the first and second depths and the first and second radioactivity counts. 99m The attenuation coefficient of Tc in the target tissue is determined by comprehensively considering the influence of factors such as scattering effect and energy window on the attenuation coefficient. This makes the attenuation coefficient obtained by actual measurement more reflective of actual clinical work. Compared with the result of calculating GFR value using the theoretical value of attenuation coefficient, it is more accurate, thus providing strong data support for medical staff to assess and diagnose corresponding diseases.

Description

Technical Field

[0001] This invention relates to the field of nuclear medicine imaging technology, and in particular to a SPECT-based imaging method. 99m Methods for determining the attenuation coefficient of Tc, methods for calculating GFR value, and systems. Background Technology

[0002] Glomerular filtration rate (GFR) is helpful in assessing and diagnosing a wide range of kidney diseases, and is typically assessed by acquiring images of kidney function using various radionuclides. Currently, dynamic renal imaging commonly uses the Gates method to calculate the glomerular filtration rate, expressed by the following formula:

[0003]

[0004] Where: μ' represents the attenuation coefficient of the radionuclide in kidney tissue, A 右 B 右 A represents the radioactivity count measured in the right kidney and the radioactivity count in the background tissue surrounding the right kidney, respectively. 左 B 左 These represent the radioactivity count measured in the left kidney and the radioactivity count in the background tissue surrounding the left kidney, respectively. (d) 右 ,d 左 The depths of the right and left kidneys are represented respectively, and C' represents the drug count.

[0005] When calculating GFR using the Gates method described above, the attenuation coefficient is typically substituted into the theoretical value of 0.153 cm⁻¹ for narrow-beam gamma rays under scattering-free conditions. -1 Calculations are performed, but in practice, due to scattering, SPECT instruments typically use a wide window of 140 keV ± 10% for data acquisition and counting. Studies have shown that under these conditions, the actual attenuation coefficient is approximately 0.10–0.14 cm⁻¹. -1 If we still use the theoretical value of 0.153cm, then... -1 When performing calculations, the calculated GFR value will be significantly overestimated compared to the actual GFR value. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a SPECT / CT-based... 99m The invention relates to a method for measuring the attenuation coefficient of Tc, a method for calculating the GFR value, and a system for doing so, in order to solve the problem that the GFR value is seriously underestimated due to inaccurate attenuation coefficients in the prior art.

[0007] To achieve the above objectives, a first aspect of the present invention provides a SPECT / CT-based... 99m The method for determining the attenuation coefficient of Tc includes the following steps:

[0008] S1: Measure the distance from the first side of the body surface and the second side opposite to the first side of the body surface to the center of the target tissue, and calculate the first depth and the second depth from the body surface to the center of the target tissue;

[0009] S2: Conduct target organization 99m SPECT / CT dynamic imaging of Tc synchronously acquires the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface within a preset time.

[0010] S3: Calculate and measure the first and second radioactivity counts based on the first and second depths and the first and second radioactivity counts on the first and second sides of the body surface. 99m Tc attenuation coefficient in the target tissue.

[0011] Furthermore, step S1 includes the following sub-steps:

[0012] S101: Perform a CT pre-scan on the target tissue to obtain a CT scan image of the target tissue;

[0013] S102: Based on the CT scan images, determine the first distal distance and the first proximal distance from the first side of the body surface to the farthest and nearest ends of the target tissue, and calculate the first depth from the first side of the body surface to the center of the target tissue.

[0014] S103: Based on the CT scan images, measure the second distal distance and the second proximal distance from the second side of the body surface to the farthest and nearest ends of the target tissue, and calculate the second depth from the second side of the body surface to the center of the target tissue.

[0015] Furthermore, step S2 includes the following sub-steps:

[0016] S201: Conducting assessments of the target organization 99m SPECT / CT dynamic imaging of Tc and acquisition of anterior and posterior images of the target tissue;

[0017] S202: Based on the anterior and posterior images of the target tissue, simultaneously acquire the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface.

[0018] Further, in step S202, the first radioactivity count includes a first peak radioactivity count and a first average radioactivity count, and the second radioactivity count includes a second peak radioactivity count and a second average radioactivity count; step S202 includes the following steps:

[0019] S2021: Segment the front and rear view images of the target tissue to determine the target tissue region and the surrounding background tissue region of the target tissue;

[0020] S2022: Synchronously collect the first peak radioactivity count and the second peak radioactivity count on the first and second sides of the body surface in the corresponding target tissue area within a preset time, as well as the first average radioactivity count and the second average radioactivity count in the background tissue area surrounding the corresponding target tissue.

[0021] Furthermore, in step S2021, the anteroposterior images of the target tissue are segmented using the ROI (Region of Interest), specifically as follows:

[0022] The influence of the front and rear images is processed in grayscale, and the outline of the target tissue is pre-marked in the front and rear image images;

[0023] A region of interest is determined in the pre-labeled front and rear image frames. Based on the region of interest, the front and rear image frames are segmented into a foreground region and a background region, wherein the foreground region is the target tissue region and the background region is the background region surrounding the target tissue.

[0024] Furthermore, in step S3, the attenuation coefficient is calculated using the following formula:

[0025]

[0026] Where: μ is the attenuation coefficient, d F ,d R These are the first depth and the second depth, respectively, A F B F These are the first peak radioactivity count on the first side of the body surface and the first average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period. R B R These are the second peak radioactivity count on the second side of the body surface and the second average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period.

[0027] Furthermore, following step S3, the following steps are also included:

[0028] S4: Repeat steps S1 to S3 to determine the attenuation coefficients of several similar target tissues, and average the attenuation coefficients.

[0029] A second aspect of the present invention also provides a SPECT / CT-based method. 99m The attenuation coefficient measurement system for Tc includes:

[0030] The depth measurement module is used to measure the distance from the first side of the body surface and the second side opposite to the first side of the body surface to the center of the target tissue, and to calculate the first depth and the second depth from the body surface to the center of the target tissue.

[0031] The radioactive counting and acquisition module is used to analyze target tissue.99 Tc m SPECT / CT dynamic imaging, simultaneously acquiring the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface within a preset time; and

[0032] The attenuation coefficient calculation module is used to calculate and measure the attenuation coefficient based on the first depth and the second depth, and the first and second radioactivity counts on the first and second sides of the body surface. 99 Tc m Attenuation coefficient in the target tissue.

[0033] A third aspect of the present invention also provides a method for calculating GFR values ​​based on SPECT / CT, comprising the following steps:

[0034] P1: Using the SPECT / CT-based method described above. 99m Method for determining the attenuation coefficient of Tc 99m The attenuation coefficient of Tc in the target tissue;

[0035] P2: Calculate the GFR value of the target tissue based on the attenuation coefficient, the first radioactivity count, and the second radioactivity count.

[0036] A fourth aspect of the present invention also provides a SPECT / CT-based GFR value calculation system, comprising:

[0037] The attenuation coefficient measurement module is used to perform SPECT / CT-based measurements as described in any one of claims 1 to 7. 99 Tc m Attenuation coefficient determination method 99m The attenuation coefficient of Tc in the target tissue; and

[0038] The GFR value calculation module is used to calculate the GFR value of the target tissue based on the attenuation coefficient, the first radioactivity count, and the second radioactivity count.

[0039] This invention simultaneously performs radioactivity counting on the first and second sides of the target tissue's surface. Using the simultaneously acquired radioactivity counts from both sides, a linear attenuation formula is applied for conversion to obtain the actual attenuation coefficient of the radionuclide in the target tissue. During this process, images of the target tissue and corresponding radioactivity counts are acquired using a SPECT / CT instrument. Factors such as scattering effects and energy windows are comprehensively considered in the image of the attenuation coefficient, making the actually measured attenuation coefficient more reflective of clinical practice. This allows for the calculation of a more accurate GFR value, providing strong data support for medical personnel to assess and diagnose corresponding diseases. Furthermore, when converting the radioactivity counts measured on both sides of the body surface using the linear attenuation formula, CT measurement is used to obtain the actual depth of the target tissue. The measurement results are accurate and reliable, thereby reducing the error caused by the depth of the target tissue in the attenuation coefficient measurement. Attached Figure Description

[0040] Figure 1 This is the SPECT / CT-based embodiment of the present invention. 99m A flowchart of the method for determining the attenuation coefficient of Tc.

[0041] Figure 2 This is a flowchart of step S1.

[0042] Figure 3 The CT scan image used to determine the distance to the first side of the target tissue surface in step S1.

[0043] Figure 4 The CT scan image used in step S1 to determine the distance to the second side of the target tissue surface.

[0044] Figure 5 This is a flowchart of step S2.

[0045] Figure 6 This is a flowchart of step S202.

[0046] Figure 7 This is the SPECT / CT-based embodiment of the present invention, which is shown in Example 2 of the present invention. 99m Block diagram of the Tc attenuation coefficient measurement system.

[0047] Figure 8 This is a flowchart of the GFR value calculation method based on SPECT / CT according to Embodiment 3 of the present invention.

[0048] Figure 9 for Figure 8 The flowchart for step P1.

[0049] Figure 10 This is a structural block diagram of the SPECT / CT-based GFR value calculation system of Embodiment 4 of the present invention. Detailed Implementation

[0050] The following detailed description illustrates the specific implementation method:

[0051] Example 1

[0052] This embodiment is based on SPECT / CT. 99m The method for determining the attenuation coefficient of Tc involves measuring the distance from the center of the target tissue to the first and second sides of the body surface to obtain the corresponding depth from the center of the target tissue to the first and second sides of the body surface. The target tissue is then subjected to SPECT / CT dynamic imaging using a radionuclide to extract the target tissue region and its corresponding surrounding background tissue region. Radioactivity counts are performed on both the target tissue region and the surrounding background region to obtain the peak radioactivity count in the target tissue region and the average radioactivity count in the surrounding background region. The background count (i.e., the average radioactivity count) is subtracted from the peak radioactivity count. The actual attenuation coefficient of the radionuclide in the target tissue is then obtained using a linear attenuation formula combined with the depth from the center of the target tissue to the first and second sides of the body surface. The following example will use a radionuclide... 99m Tc. The method of this embodiment, targeting the kidneys (including the left and right kidneys), will be described in detail. It is understood that the method of this embodiment is not limited to using... 99m Tc dynamic imaging is not limited to the determination of the attenuation coefficient of radionuclides in the kidneys, but is also applicable to the determination of the attenuation coefficient of other radionuclides in any tissue of the human body.

[0053] like Figure 1 As shown, this embodiment is based on SPECT / CT. 99m A flowchart of the method for determining the attenuation coefficient of Tc. Specifically, this embodiment is based on SPECT / CT. 99m The method for determining the attenuation coefficient of Tc includes the following steps:

[0054] S1: Determine the first and second depths.

[0055] Specifically, CT scan images of the kidneys are acquired, and the distances from the first side of the body surface (front of the body surface in this embodiment) and the second side of the body surface (back of the body surface in this embodiment) to the center of the kidneys are measured respectively. The first depth from the first side of the body surface to the center of the kidneys and the second depth from the second side of the body surface to the center of the kidneys are calculated.

[0056] like Figure 2 As shown, step S1 includes the following steps:

[0057] S101: Perform a CT pre-scan on the target tissue.

[0058] The patient's lower abdomen was pre-scanned using computed tomography (CT) to obtain CT images of the kidneys.

[0059] S102: Determine the first depth from the first side of the body surface to the center of the target tissue.

[0060] like Figure 3 As shown, the left kidney is selected, and the position of the nearest end from the first side of the body surface to the anterior side of the left kidney is determined in the CT scan image. The distance from the first side of the body surface to the nearest end is measured to obtain the first proximal distance from the first side of the body surface to the nearest end of the anterior side of the left kidney. Then, the position of the farthest end from the first side of the body surface to the posterior side of the left kidney is determined, and the distance from the first side of the body surface to the farthest end is measured to obtain the first distal distance from the first side of the body surface to the farthest end of the posterior side of the left kidney. Finally, the first depth from the first side of the body surface to the center of the left kidney is calculated based on the first distal distance and the first proximal distance.

[0061] In this embodiment, the first depth from the first side of the body surface to the center of the left kidney is calculated using the following formula:

[0062]

[0063] Where: d F For the first depth, L l1 ,L l2 These are the first distal distance and the first proximal distance from the first side of the body surface to the farthest and nearest ends of the left kidney, respectively.

[0064] In this embodiment, the depth from the center of the right kidney to the first side of the body surface is the same as that of the left kidney. For details, please refer to the relevant description of the depth measurement from the center of the left kidney to the first side of the body surface described above.

[0065] In other embodiments, to ensure the accuracy of the first depth measurement, multiple CT pre-scans can be performed on the same patient at the same location to obtain multiple CT scan images. The corresponding first depth is measured based on each CT scan image, and finally the average of the multiple measured first depths is processed to improve the accuracy of the first depth measurement.

[0066] S103: Determine the second depth from the second side of the body surface to the center of the target tissue.

[0067] like Figure 4As shown, the left kidney is also selected. The position of the closest end from the second side of the body surface to the posterior side of the left kidney is determined in the CT scan image. The distance from the second side of the body surface to the closest end is measured to obtain the second proximal distance from the second side of the body surface to the closest end of the posterior side of the left kidney. Then, the position of the farthest end from the second side of the body surface to the anterior side of the left kidney is determined. The distance from the second side of the body surface to the farthest end is measured to obtain the second distal distance from the second side of the body surface to the farthest end of the anterior side of the left kidney. Finally, the second depth from the second side of the body surface to the center of the left kidney is calculated based on the second distal distance and the second proximal distance.

[0068] In this embodiment, the second depth from the second side of the body surface to the center of the left kidney is calculated using the following formula:

[0069]

[0070] Where: d R For the second depth, L r1 ,L r2 These are the second distal distance and the second proximal distance from the second side of the body surface to the farthest and nearest ends of the left kidney, respectively.

[0071] In this embodiment, the depth from the center of the right kidney to the second side of the body surface is the same as that of the left kidney. For details, please refer to the relevant description of the depth measurement from the center of the left kidney to the second side of the body surface described above.

[0072] In other embodiments, to ensure the accuracy of the second depth measurement results, multiple CT pre-scans can be performed on the same patient at the same location to obtain multiple CT scan images. The corresponding second depth is measured based on each CT scan image, and finally the average of the multiple measured second depths is processed to improve the accuracy of the second depth measurement.

[0073] S2: Perform dynamic imaging of the target tissue and collect radioactivity counts.

[0074] Specifically, targeting the organization 99m SPECT / CT dynamic imaging of Tc, and synchronously acquiring the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface within a preset time.

[0075] like Figure 5 As shown, step S2 includes the following sub-steps:

[0076] S201: Acquire anterior and posterior images of the target tissue.

[0077] Using a SPECT / CT scanner, the anterior and posterior probes of the SPECT / CT scanner are activated to simultaneously acquire anteroposterior images of the kidney for dynamic imaging, in order to perform [further imaging] on the target tissue. 99m SPECT / CT dynamic imaging of Tc.

[0078] In some other embodiments, when performing dynamic renal imaging, additional methods may be used besides... 99m Other radionuclides besides Tc.

[0079] S202: Simultaneously collect the first and second radioactivity counts on the first and second sides of the body surface.

[0080] Specifically, based on anteroposterior images of the target tissue, the kidney region and the surrounding background tissue region are determined. A first radioactivity count is simultaneously acquired on a first side of the body surface, and a second radioactivity count is acquired on a second side of the body surface. In this embodiment, the first radioactivity count includes a first peak radioactivity count corresponding to the kidney region and a first average radioactivity count corresponding to the surrounding background tissue region of the kidney, acquired on the first side of the body surface; the second radioactivity count includes a second peak radioactivity count corresponding to the kidney region and a second average radioactivity count corresponding to the surrounding background tissue region of the kidney, acquired on the second side of the body surface.

[0081] like Figure 6 As shown, step S202 includes the following steps:

[0082] S2021: Segment the front and rear images to determine the target tissue region and the surrounding background tissue region.

[0083] First, grayscale processing is performed on the anterior and posterior images. Based on the contour of the kidney, several contour points are determined, and the contour curve of the kidney is obtained by fitting two adjacent contour points. The contour curves are then used to form the contour line of the kidney, thereby obtaining the kidney contour and pre-marking the kidney contour.

[0084] Then, the region of interest is determined in the pre-labeled anteroposterior images, which is the kidney region and its corresponding surrounding background tissue region in the anteroposterior images;

[0085] Finally, the foreground region (i.e., the kidney region marked with an outline) and the background region (i.e., the surrounding background tissue region outside the outline) are extracted within the region of interest, thereby completing the segmentation of the kidney region and the surrounding background tissue region in the anterior and posterior view images.

[0086] In this embodiment, when segmenting the region of interest, experienced medical personnel can be selected to delineate the kidney outline within the region of interest to determine the kidney region and the surrounding background tissue region, thereby achieving segmentation of the anterior and posterior view images.

[0087] Of course, in other embodiments, to improve the segmentation accuracy of the anterior and posterior images, a binary segmentation method can also be used to segment the kidney region and the surrounding background tissue region within the region of interest. Specifically, a grayscale threshold is determined using a threshold iteration method; based on the determined grayscale threshold, all pixels in the grayscale-processed anterior and posterior images are binarized to segment the anterior and posterior images into foreground and background regions, thereby segmenting the kidney region and the surrounding background tissue region. More specifically, when determining the grayscale threshold using the threshold iteration method, firstly, the grayscale values ​​of all pixels in the preceding and following image slices are calculated, and the average of all grayscale values ​​is processed to obtain a first grayscale average value, which is used as an initial grayscale threshold. Then, based on this initial grayscale threshold, each pixel in the preceding and following image slices is divided into a first part and a second part, and the average value of all pixels contained in the first part and the second part is calculated respectively, denoted as the second grayscale average value. Next, the second grayscale average value of the first part and the second grayscale average value of the second part are averaged to obtain a second grayscale threshold. Finally, it is determined whether the probability of the grayscale value corresponding to the initial grayscale threshold and the probability of the grayscale value corresponding to the second grayscale threshold satisfy the threshold iteration calculation formula. The threshold iteration calculation formula is expressed as follows:

[0088] q0(T C+1 )=p(T C+1 )+q0(T C (3)

[0089] Where: q0(T) C q0(T) represents the probability of the gray value appearing corresponding to the initial gray threshold. C+1 p(T) represents the probability of the gray value corresponding to the second gray threshold appearing. C+1 The grayscale value corresponding to the second grayscale threshold is T. C+1 The probability of.

[0090] If the initial grayscale threshold T is obtained c The probability of the corresponding grayscale value appearing and the second grayscale threshold T c+1 If the probability of the corresponding gray value appearing is sufficient to make the above formula (3) hold, then the second gray threshold T is used. c+1 The final grayscale threshold is used to segment the foreground and background regions of the image.

[0091] If the initial grayscale threshold T is obtained c The probability of the corresponding grayscale value appearing and the second grayscale threshold T c+1If the probability of the corresponding gray value appearing does not make the above formula (3) true, then the second gray threshold is regarded as the initial gray threshold in step b, and step b is repeated until the obtained gray threshold and the previous gray threshold satisfy the iterative calculation formula of the threshold, so as to determine the final gray threshold.

[0092] This allows for higher precision compared to manually marking the kidney area by medical staff, resulting in a more accurate final radioactivity count.

[0093] S2022: Synchronous collection of radioactivity counts.

[0094] Specifically, simultaneous sampling of the first and second sides of the body surface was performed. 99m The first and second peak radioactivity counts of the corresponding kidney region, and the first and second average radioactivity counts of the surrounding background tissue region, are obtained under SPECT / CT dynamic imaging of Tc. In this embodiment, to ensure the accuracy and reliability of the radioactivity counts, images acquired over a period of 2.5 to 3 minutes are preferred.

[0095] S3: Calculate and determine the attenuation coefficient.

[0096] Because under the same conditions and measurement time, the actual radioactivity counts obtained by subtracting the background count (i.e., the average radioactivity count) from the peak radioactivity counts on the same side and converting them using the linear decay formula are equal. Specifically, based on the first and second depths measured in step S1, and the first peak radioactivity count, first average radioactivity count, second peak radioactivity count, and second average radioactivity count measured in step S2, combined with the equality of the actual radioactivity counts between the first and second sides of the body surface, the actual radioactivity counts can be calculated and measured. 99m Tc attenuation coefficient in the target tissue.

[0097] In this embodiment, the equality of the actual radioactivity counts on the first and second sides of the body surface is expressed as follows:

[0098]

[0099] Where: μ is the attenuation coefficient, d F ,d R These are the first depth and the second depth, respectively, A F B F These are the first peak radioactivity count on the first side of the body surface and the first average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period. R B RThese are the second peak radioactivity count on the second side of the body surface and the second average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period.

[0100] By converting the above formula (4), we can obtain 99m The attenuation coefficient of Tc in the target tissue, wherein the attenuation coefficient is expressed as:

[0101]

[0102] As a preferred embodiment, to further improve the accuracy of attenuation coefficient measurement, the following steps are included after step S3:

[0103] S4: Optimize the attenuation coefficient.

[0104] Specifically, repeat steps S1 to S3, and measure under the same measurement conditions. 99m The attenuation coefficients of Tc in the kidneys of several patients were obtained, resulting in several attenuation coefficients. These attenuation coefficients were then averaged to obtain the final actual value of the attenuation coefficient based on SPECT / CT. In this embodiment, an arithmetic mean can be used to average the attenuation coefficients. However, in other embodiments, a weighted mean can be used, where the attenuation coefficients measured for each patient are weighted according to individual patient differences to calculate the final attenuation coefficient.

[0105] To verify the accuracy of this embodiment, the attenuation coefficient will be measured in 25 patients of different ages, genders, heights, and weights. The patients' physical conditions are shown in Table 1 below:

[0106]

[0107]

[0108] Table 1

[0109] The method of this embodiment was used to measure the patients in Table 1 above. 99m The attenuation coefficient of Tc for different kidneys, and the relevant data of the measurement process are shown in Table 2 below:

[0110]

[0111]

[0112] Table 2

[0113] Table 2 above shows that the average attenuation coefficient of the 25 patients is 0.115, which is consistent with the actual attenuation coefficient of SPECT / CT using a wide window acquisition technique of 140keV±10% under scattering conditions.

[0114] This embodiment is based on SPECT / CT. 99m The method for determining the attenuation coefficient of Tc involves simultaneously counting radioactivity on the first and second sides of the kidney's surface. The radioactivity counts from both sides, acquired simultaneously, are converted using a linear attenuation formula to obtain the actual attenuation coefficient of the radionuclide in the kidney. During this process, images of the kidney and corresponding radioactivity counts are acquired using SPECT / CT, taking into account factors such as scattering effects and energy windows. This ensures that the measured attenuation coefficient more accurately reflects clinical practice. Furthermore, when converting the radioactivity counts measured on both sides of the body surface using the linear attenuation formula, the actual depth of the kidney is measured using CT, resulting in accurate and reliable measurements that reduce the error caused by kidney depth in the attenuation coefficient determination.

[0115] Example 2

[0116] like Figure 7 As shown, this embodiment is based on SPECT / CT. 99m System block diagram of the Tc attenuation coefficient measurement system. This embodiment is based on SPECT / CT. 99m The Tc attenuation coefficient measurement system is mainly used to realize the SPECT / CT-based measurement as described in Example 1. 99m Method for determining the attenuation coefficient of Tc. Specifically, this embodiment is based on SPECT / CT. 99m The attenuation coefficient measurement system for Tc includes a depth measurement module 201, a radioactivity counting and acquisition module 202, and an attenuation coefficient calculation module 203; wherein:

[0117] The depth measurement module 201 is used to measure the distance from the first side of the body surface and the second side opposite to the first side of the body surface to the center of the kidney, and to calculate the first depth and the second depth from the body surface to the center of the kidney. Specifically, the depth measurement module 201 acquires CT scan images of the kidney, determines the positions of the farthest and nearest ends from the first side of the body surface and the second side of the body surface to the center of the kidney, and calculates the first depth from the first side of the body surface to the center of the kidney and the second depth from the second side of the body surface to the center of the kidney based on the positions of the first side of the body surface and the second depth from the second side of the body surface to the center of the kidney, respectively. In this embodiment, the specific process of the depth measurement module 201 measuring the first depth and the second depth is described in step S1 of Embodiment 1, and will not be repeated in this embodiment.

[0118] The radioactive counting and acquisition module 201 is used to perform radioactive counting on the kidneys. 99 Tc m The system performs SPECT / CT dynamic imaging and simultaneously acquires a first radioactivity count on the first side of the body surface and a second radioactivity count on the second side of the body surface within a preset time period. Specifically, the first radioactivity counting module 201 simultaneously acquires anteroposterior images of the kidney dynamic imaging to perform... 99m SPECT / CT dynamic imaging of Tc, based on anteroposterior images of the kidney, determines the kidney region and the surrounding background tissue region. The SPECT / CT instrument simultaneously acquires a first radioactivity count on the first side of the body surface and a second radioactivity count on the second side. In this embodiment, the specific process of the first radioactivity counting module 201 acquiring the first and second radioactivity counts is described in step S2 of Embodiment 1, and will not be repeated here.

[0119] The attenuation coefficient calculation module 203 is used to calculate and measure the attenuation coefficient based on the first and second depths measured by the depth measurement module 201 and the first and second radioactive counts measured by the radioactive count acquisition module 202 on the first and second sides of the body surface. 99 Tc m The attenuation coefficient in the kidney. Specifically, the first radioactivity count includes a first peak radioactivity count corresponding to the kidney region collected on the first side of the body surface and a first average radioactivity count corresponding to the background tissue region surrounding the kidney; the second radioactivity count includes a second peak radioactivity count corresponding to the kidney region collected on the second side of the body surface and a second average radioactivity count corresponding to the background tissue region surrounding the kidney. In this embodiment, the specific process of the attenuation coefficient calculation module 203 calculating and measuring the attenuation coefficient is described in step S3 of Embodiment 1, and will not be repeated in this embodiment.

[0120] As a preferred embodiment, a mean processing module 204 is also included. The mean processing module 204 is used to measure several attenuation coefficients under multiple identical conditions, and then perform mean processing on the several attenuation coefficients to obtain a more accurate, reliable and clinically suitable attenuation coefficient.

[0121] This embodiment is based on SPECT / CT. 99mThe Tc attenuation coefficient measurement system, through the setting of a depth measurement module 201, uses CT to measure the actual depth of the kidney. The measurement results are accurate and reliable, and can reduce the error caused by the kidney depth in the attenuation coefficient measurement. At the same time, through the setting of a radioactive counting acquisition module 202 and an attenuation coefficient calculation module 203, radioactive counts are performed on the first and second sides of the body surface simultaneously, and the conversion is performed using a linear attenuation formula to obtain the actual attenuation coefficient of the radionuclide in the kidney, so as to truly reflect the clinical work.

[0122] Example 3

[0123] like Figure 8 The diagram shows a flowchart of the SPECT / CT-based GFR value calculation method of this embodiment. This SPECT / CT-based GFR value calculation method is implemented based on the attenuation coefficient measured by the method in Embodiment 1. By using the attenuation coefficient measured in Embodiment 1 to calculate the actual GFR, a more accurate GFR value is obtained. Specifically, the SPECT / CT-based GFR value calculation method of this embodiment includes the following steps:

[0124] P1: Measure the attenuation coefficient.

[0125] Specifically, the SPECT / CT-based method described in Example 1 is employed. 99m Method for determining the attenuation coefficient of Tc 99m The attenuation coefficient of Tc in the target tissue.

[0126] like Figure 9 As shown, step P1 includes the following steps:

[0127] P101: Determine the first and second depths.

[0128] Specifically, CT scan images of the kidneys are acquired, and the distances from the first side of the body surface (front of the body surface in this embodiment) and the second side of the body surface (back of the body surface in this embodiment) to the center of the kidneys are measured respectively. The first depth from the first side of the body surface to the center of the kidneys and the second depth from the second side of the body surface to the center of the kidneys are calculated.

[0129] P102: Perform dynamic imaging of the target tissue and collect radioactivity counts.

[0130] Specifically, targeting the organization 99m SPECT / CT dynamic imaging of Tc, and synchronously acquiring the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface within a preset time.

[0131] P103: Calculate and determine the attenuation coefficient.

[0132] Because under the same conditions and measurement time, the actual radioactivity counts obtained by subtracting the background count (i.e., the average radioactivity count) from the peak radioactivity counts on the same side and converting them using the linear decay formula are equal. Specifically, based on the first and second depths measured in step S1, and the first peak radioactivity count, first average radioactivity count, second peak radioactivity count, and second average radioactivity count measured in step S2, combined with the equality of the actual radioactivity counts between the first and second sides of the body surface, the actual radioactivity counts can be calculated and measured. 99m Tc attenuation coefficient in the target tissue.

[0133] P104: Optimize the attenuation coefficient.

[0134] Specifically, repeat steps P101 to P103, and measure under the same measurement conditions. 99m The attenuation coefficients of Tc in the kidneys of several patients were obtained, resulting in several attenuation coefficients. These attenuation coefficients were then averaged to obtain the final actual value of the attenuation coefficient based on SPECT / CT. In this embodiment, an arithmetic mean can be used to average the attenuation coefficients. However, in other embodiments, a weighted mean can be used, where the attenuation coefficients measured for each patient are weighted according to individual patient differences to calculate the final attenuation coefficient.

[0135] In this embodiment, steps P101 to P104 correspond one-to-one with steps S1 to S4 in Embodiment 1. For a detailed description, please refer to the relevant description in Embodiment 1. This embodiment will not repeat the details.

[0136] P2: Calculate the GFR value of the target tissue.

[0137] The GFR value of the target tissue is calculated based on the attenuation coefficient measured in step P1 and the first and second radioactive counts. In this embodiment, the GFR value is calculated using the Gates method, and the calculation formula is as follows:

[0138]

[0139] Where: μ is 99m The attenuation coefficient of Tc in kidney tissue, A r B r The radioactivity counts measured in the right kidney and the background radioactivity counts in the right kidney's surrounding tissues are respectively A. l B l These represent the radioactivity count measured in the left kidney and the radioactivity count in the background tissue surrounding the left kidney, respectively. (d) r ,d l The depths of the right and left kidneys are indicated, respectively, and C represents the drug count.

[0140] The GFR value calculation method based on SPECT / CT in this embodiment calculates GFR values ​​by... 99m The determination of the actual attenuation coefficient of Tc in kidney tissue, and the calculation of GFR value based on this actual attenuation coefficient, can yield a relatively accurate and reliable GFR value, thus providing strong data support for medical staff to assess and diagnose kidney diseases.

[0141] Example 4

[0142] like Figure 10 The diagram shown is a structural block diagram of the SPECT / CT-based GFR value calculation system of this embodiment. This SPECT / CT-based GFR value calculation system is mainly used to implement the SPECT / CT-based GFR value calculation method described in Embodiment 3. Specifically, the SPECT / CT-based GFR value calculation system of this embodiment includes an attenuation coefficient measurement module 401 and a GFR value calculation module 402; wherein:

[0143] The attenuation coefficient measuring module 401 is used for measuring... 99m The attenuation coefficient of Tc in the kidney was determined. Specifically, the attenuation coefficient measurement module 401 measured the distance from the center of the kidney to the first and second sides of the body surface to obtain the first depth and the second depth, and then applied a method to the kidney. 99m SPECT / CT dynamic imaging with Tc was performed to extract the kidney region and its corresponding surrounding background tissue region. Radioactivity counts were performed on both the kidney region and the surrounding background region to obtain the corresponding peak and average radioactivity counts. Finally, the results were obtained using a linear attenuation formula combined with the first and second depths. 99m The actual attenuation coefficient of Tc in the kidney. In this embodiment, the specific process of attenuation coefficient measurement module 401 for attenuation coefficient measurement is described in step P1 of embodiment 1 or embodiment 3, and will not be repeated in this embodiment.

[0144] The GFR value calculation module 402 is used to calculate the GFR value of the kidney based on the attenuation coefficient measured by the attenuation coefficient measurement module 401, as well as the first radioactivity count and the second radioactivity count. In this embodiment, the specific process by which the GFR value calculation module 402 calculates the actual GFR value is described in step P2 of embodiment 3, and will not be repeated in this embodiment.

[0145] The SPECT / CT-based GFR value calculation system in this embodiment uses an attenuation coefficient measurement module 401 to... 99mThe determination of the actual attenuation coefficient of Tc in kidney tissue, and the calculation of GFR value based on this actual attenuation coefficient by setting up a GFR value calculation module, can obtain a relatively accurate and reliable GFR value, thus providing strong data support for medical staff to assess and diagnose kidney diseases.

Claims

1. SPECT / CT based 99m The method for determining the attenuation coefficient of Tc is characterized by, Includes the following steps: S1: Measure the distance from the first side of the body surface and the second side opposite to the first side of the body surface to the center of the target tissue, and calculate the first depth and the second depth from the body surface to the center of the target tissue; S2: performing on the target tissue 99m SPECT / CT dynamic imaging of Tc, synchronously acquiring first radioactivity counts of a first side of the body surface and second radioactivity counts of a second side of the body surface within a preset time; the first radioactivity counts include first peak radioactivity counts of a target tissue region corresponding to the first side of the body surface and first average radioactivity counts of surrounding background tissue of the target tissue, and the second radioactivity counts include second peak radioactivity counts of a target tissue region corresponding to the second side of the body surface and second average radioactivity counts of surrounding background tissue of the target tissue; S3: Calculate and measure the first and second radioactivity counts based on the first and second depths and the first and second radioactivity counts on the first and second sides of the body surface. 99m The attenuation coefficient of Tc in the target tissue is calculated using the following formula: in: The attenuation coefficient is... These are the first depth and the second depth, respectively. These are the first peak radioactivity count on the first side of the body surface and the first average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period. These are the second peak radioactivity count on the second side of the body surface and the second average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period.

2. The SPECT / CT-based method according to claim 1 99m The method for determining the attenuation coefficient of Tc is characterized by, Step S1 includes the following sub-steps: S101: Perform a CT pre-scan on the target tissue to obtain a CT scan image of the target tissue; S102: Based on the CT scan images, determine the first distal distance and the first proximal distance from the first side of the body surface to the farthest and nearest ends of the target tissue, and calculate the first depth from the first side of the body surface to the center of the target tissue. S103: Based on the CT scan images, measure the second distal distance and the second proximal distance from the second side of the body surface to the farthest and nearest ends of the target tissue, and calculate the second depth from the second side of the body surface to the center of the target tissue.

3. The SPECT / CT-based method according to claim 1 99m The method for determining the attenuation coefficient of Tc is characterized by, Step S2 includes the following sub-steps: S201: Conducting assessments of the target organization 99m SPECT / CT dynamic imaging of Tc and acquisition of anterior and posterior images of the target tissue; S202: Based on the anterior and posterior images of the target tissue, simultaneously acquire the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface.

4. The SPECT / CT-based method according to claim 3 99m The method for determining the attenuation coefficient of Tc is characterized by, In step S202, the first radioactivity count includes a first peak radioactivity count and a first average radioactivity count, and the second radioactivity count includes a second peak radioactivity count and a second average radioactivity count; step S202 includes the following steps: S2021: Segment the front and rear view images of the target tissue to determine the target tissue region and the surrounding background tissue region of the target tissue; S2022: Synchronously collect the first peak radioactivity count and the second peak radioactivity count on the first and second sides of the body surface in the corresponding target tissue area within a preset time, as well as the first average radioactivity count and the second average radioactivity count in the background tissue area surrounding the corresponding target tissue.

5. The SPECT / CT-based method according to claim 4 99m The method for determining the attenuation coefficient of Tc is characterized by, In step S2021, the anteroposterior images of the target tissue are segmented using the Region of Interest (ROI). The specific method is as follows: The front and rear images are processed in grayscale, and the outline of the target tissue is pre-marked in the front and rear images; A region of interest is determined in the pre-labeled front and rear image frames. Based on the region of interest, the front and rear image frames are segmented into a foreground region and a background region, wherein the foreground region is the target tissue region and the background region is the background region surrounding the target tissue.

6. The SPECT / CT-based method according to claim 1 99m The method for determining the attenuation coefficient of Tc is characterized by, Following step S3, the following steps are also included: S4: Repeat steps S1 to S3 to determine the attenuation coefficients of several similar target tissues, and average the attenuation coefficients.

7. SPECT / CT based 99m The attenuation coefficient measurement system for Tc is characterized in that, include: The depth measurement module is used to measure the distance from the first side of the body surface and the second side opposite to the first side of the body surface to the center of the target tissue, and to calculate the first depth and the second depth from the body surface to the center of the target tissue. The radioactivity counting acquisition module is used to perform 99Tcm SPECT / CT dynamic imaging on the target tissue and simultaneously acquire the first radioactivity count on the first side of the body surface and the second radioactivity count on the second side of the body surface within a preset time. The first radioactivity count includes the first peak radioactivity count of the target tissue area corresponding to the first side of the body surface and the first average radioactivity count of the surrounding background tissue of the target tissue. The second radioactivity count includes the second peak radioactivity count of the target tissue area corresponding to the second side of the body surface and the second average radioactivity count of the surrounding background tissue of the target tissue. as well as The attenuation coefficient calculation module is used to calculate and determine the attenuation coefficient of 99Tcm in the target tissue based on the first depth and the second depth, and the first and second radioactive counts on the first and second sides of the body surface. The attenuation coefficient is calculated using the following formula: in: The attenuation coefficient is... These are the first depth and the second depth, respectively. These are the first peak radioactivity count on the first side of the body surface and the first average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period. These are the second peak radioactivity count on the second side of the body surface and the second average radioactivity count of the background tissue surrounding the target tissue, respectively, within a preset time period.

8. A method for calculating GFR values ​​based on SPECT / CT, characterized in that, Includes the following steps: P1: Using SPECT / CT based as described in any one of claims 1 to 6 99m Method for determining the attenuation coefficient of Tc 99m The attenuation coefficient of Tc in the target tissue; P2: Calculate the GFR value of the target tissue based on the attenuation coefficient, the first radioactivity count, and the second radioactivity count.

9. A GFR value calculation system based on SPECT / CT, characterized in that, include: The attenuation coefficient measurement module is used to perform SPECT / CT-based measurements as described in any one of claims 1 to 6. 99 Tc m Attenuation coefficient determination method 99m The attenuation coefficient of Tc in the target tissue; as well as The GFR value calculation module is used to calculate the GFR value of the target tissue based on the attenuation coefficient, the first radioactivity count, and the second radioactivity count.

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