Photon counting equipment and counting rate correction method thereof

Abstract

The invention discloses photon counting equipment and a counting rate correction method thereof, and relates to the technical field of medical imaging. According to the method, after to-be-corrected first counting data is obtained, reference counting data similar to the first counting data can be determined from multiple pieces of second counting data, and the actual counting rate of each energy interval in the first counting data is calculated according to the ideal counting data corresponding to the reference counting data. The count rate is corrected to be an ideal count rate without a pile up effect. Therefore, correction of the first counting data can be realized to obtain a relatively accurate counting rate of each energy interval, so that the quality of an image obtained based on the corrected first counting data can be ensured to be relatively good.

Description

Technical Field

[0001] The present application relates to the field of medical imaging technology, and in particular to a photon counting device and a counting rate correction method thereof. Background Art

[0002] A photon counting computed tomography (CT) device includes a detector (also called a photon counting detector), which includes a plurality of detection units. The detector is capable of recording the number of photons captured by each detector unit and the energy carried by each photon, and classifying the photons into different energy intervals according to the energy of the photons. The energy of the photons received by any two energy intervals is different.

[0003] However, in the process of the detection unit receiving photons, if multiple photons arrive at the detection unit with a time interval less than the dead time, a pulse stacking phenomenon will occur, that is, the detector will record the multiple incident photons as one photon, and the energy of the photons will also be superimposed on each other during the recording process, resulting in a large difference between the number of photons in each energy interval finally recorded and the actual number, thereby resulting in a low accuracy of the counting rate in each energy interval. Summary of the invention

[0004] The present application provides a photon counting device and a counting rate correction method thereof, which can solve the problem of low accuracy of the counting rate in each energy interval of the detection unit. The technical solution is as follows:

[0005] In one aspect, a counting rate correction method for a photon counting device is provided, wherein the photon counting device comprises: a detection unit; the method comprises:

[0006] Acquire first counting data to be corrected of the detector unit, the first counting data comprising: an actual counting rate of at least one energy interval;

[0007] Based on the first counting data, determining reference counting data from a plurality of second counting data of the detection unit, each of the reference counting data having a similarity with the first counting data higher than a similarity threshold, the plurality of second counting data being obtained by the photon counting device scanning a scanning sample;

[0008] Based on the ideal counting data corresponding to the reference counting data, a correction result of the first counting data is determined, the correction result including a first ideal counting rate corresponding to the actual counting rate of each of the energy intervals.

[0009] Optionally, the number of the reference count data is multiple; and determining the correction result of the first count data based on the ideal count data corresponding to the reference count data includes:

[0010] Determine a mapping relationship between the ideal counting data and the actual counting data based on the plurality of reference counting data and the ideal counting data corresponding to each of the reference counting data;

[0011] Based on the mapping relationship, a correction result of the first counting data is determined.

[0012] Optionally, the number of the reference count data is multiple; and determining the correction result of the first count data based on the ideal count data corresponding to the reference count data includes:

[0013] Performing weighted summation on the ideal counting data corresponding to the plurality of reference counting data to obtain a correction result of the first counting data;

[0014] The weight of the ideal counting data corresponding to each of the reference counting data is proportional to the similarity between the reference counting data and the first counting data.

[0015] Optionally, the method further includes:

[0016] Determining weights of the reference count data based on similarities between each of the reference count data and the first count data;

[0017] The weight is positively correlated with the similarity.

[0018] Optionally, the number of the reference count data is one, and the reference count data has the highest similarity to the first count data; and determining a correction result of the first count data based on ideal count data corresponding to the reference count data includes:

[0019] Acquire ideal counting data corresponding to the reference counting data, the ideal counting data comprising: a second ideal counting rate of each of the energy intervals;

[0020] The second ideal counting rate in each of the energy intervals is determined as the first ideal counting rate corresponding to the actual counting rate in the energy interval in the first counting data.

[0021] Optionally, before determining the reference counting data from the plurality of second counting data of the detection unit, the method further includes:

[0022] determining a distance between each of the second counting data and the first counting data;

[0023] Based on the distance, a similarity between the second count data and the first count data is determined, and the similarity is negatively correlated with the distance.

[0024] Optionally, the number of the scan samples is multiple; before determining the reference counting data from the multiple second counting data of the detection unit, the method further includes:

[0025] Scanning a plurality of the scan samples to obtain a plurality of the second counting data;

[0026] The scan samples of any two scans are different, and / or the scan parameters are different.

[0027] Optionally, the photon counting device further includes: a ray source; before determining a correction result of the first counting data based on the ideal counting data corresponding to the reference counting data, the method further includes:

[0028] Acquire the energy spectrum of the ray emitted by the ray source each time the scanning sample is scanned, the attenuation coefficient of each material that the ray passes through before reaching the detection unit, and the path length of each material that the ray passes through;

[0029] determining ideal count data corresponding to the second count data based on the energy spectrum, the attenuation coefficient of each of the materials, and the path length of each of the materials;

[0030] Alternatively, a low-dose scan is performed on the scanned sample to obtain second counting data at different low doses, wherein the second counting data is equal to the theoretical counting data under the low-dose scan;

[0031] Based on different low doses and second counting data corresponding to the different low doses, a linear relationship between the scanning dose and the theoretical counting data is obtained;

[0032] Based on the linear relationship, ideal count data under second count data under other scanning doses are acquired.

[0033] In another aspect, a photon counting device is provided, the photon counting device comprising: a detection unit and a processor; the processor is used to:

[0034] Acquire first counting data to be corrected of the detector unit, the first counting data comprising: an actual counting rate of at least one energy interval;

[0035] Based on the first counting data, determining reference counting data from a plurality of second counting data of the detection unit, each of the reference counting data having a similarity with the first counting data higher than a similarity threshold, the plurality of second counting data being obtained by the photon counting device scanning a scanning sample;

[0036] Based on the ideal counting data corresponding to the reference counting data, a correction result of the first counting data is determined, the correction result including a first ideal counting rate corresponding to the actual counting rate of each of the energy intervals.

[0037] On the other hand, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that when the computer program is executed by a processor, the counting rate correction method of the photon counting device as described in the above aspects is implemented.

[0038] On the other hand, a computer program product is provided, characterized in that the computer program product includes a computer program or computer instructions, and when the computer program or the computer instructions are executed by a processor, the counting rate correction method of the photon counting device as described in the above aspects is implemented.

[0039] The beneficial effects brought about by the technical solution provided by this application include at least:

[0040] The present application provides a photon counting device and a counting rate correction method thereof. After obtaining the first counting data to be corrected, the method can determine reference counting data that is relatively similar to the first counting data from a plurality of second counting data, and based on the ideal counting data corresponding to the reference counting data, correct the actual counting rate of each energy interval in the first counting data to the ideal counting rate without the pile up effect. Thus, the correction of the first counting data can be achieved to obtain a relatively accurate counting rate of each energy interval, thereby ensuring that the quality of the image obtained based on the corrected first counting data is good.

[0041] Moreover, since the multiple second counting data are obtained by the photon counting device performing multiple scans on the scanning sample, that is, the multiple second counting data are the data actually collected by the detection unit, they are closer to the actual counting rate of the detection unit than the counting rate determined by means of a mathematical model. Therefore, the first counting data is corrected based on the ideal counting data corresponding to the reference counting data that is more similar to the first counting data in the multiple second counting data, thereby ensuring that the accuracy of the correction result of the first counting data is higher.

[0042] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of a photon counting CT device provided in an embodiment of the present application;

[0044] Figure 2is a schematic diagram of the structure of a photon counting detector provided in an embodiment of the present application;

[0045] Figure 3 is a flow chart of a counting rate correction method for a photon counting device provided in an embodiment of the present application;

[0046] Figure 4 is a flow chart of another counting rate correction method for a photon counting device provided in an embodiment of the present application;

[0047] Figure 5 is a distribution diagram of a plurality of second counting data provided in an embodiment of the present application;

[0048] Figure 6 It is a CT image reconstructed without pile up correction;

[0049] Figure 7 A CT image reconstructed by performing pile up correction using the method provided in the present application is provided in an embodiment of the present application;

[0050] Figure 8 A CT image reconstructed from scanning data of an energy-integrating detector provided in an embodiment of the present application;

[0051] Fig. 9 This is a structural block diagram of a photon counting device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0053] The photon counting CT device includes a detector, which includes multiple detection units. The detector can record the number of photons captured by each detector unit and the energy carried by each photon, and divide the photons into different energy intervals according to the energy of the photons. The energy of the photons received by any two energy intervals is different.

[0054] However, in the process of the detection unit capturing and receiving photons, if multiple photons arrive at the detection unit at a time interval less than the dead time, a pile-up phenomenon will occur, that is, the detector will record the multiple incident photons as one photon, and the energy of the photons will also be superimposed on each other during the recording process, resulting in a large difference between the number of photons in each energy interval finally recorded and the actual number, resulting in a low accuracy of the counting rate in each energy interval.

[0055] In the related art, a mathematical model can be established to describe the pile-up process of the detector of the photon counting CT device, and then the pile-up correction can be achieved by inverse solution. However, in the actual scanning process, the detector is affected by various factors, and its physical process of photon counting is difficult to accurately describe with a mathematical model. Therefore, the error between the count rate after pile-up determined in the related art and the count rate after pile-up in actual application is large, so the accuracy of the corrected count rate obtained by the method in the related art is low.

[0056] Figure 1 Schematic diagram of the structure of a photon counting CT device provided in an embodiment of the present application. Figure 1 As shown, the photon counting CT device includes: a scanning bed 01, a gantry 02, a radiation source 03, a photon counting detector 04, and a filter 05.

[0057] The ray source 03 and the photon counting detector 04 are both mounted on a rack 02, and the rack 02 can rotate and drive the ray source 03 and the photon counting detector 04 to rotate to scan the scanned object. The filter 05 is mounted near the ray source 03 to absorb soft rays that do not contribute to imaging. Optionally, the filter 05 can be a butterfly filter.

[0058] Figure 2 is a schematic diagram of the structure of a photon counting detector provided in an embodiment of the present application. Figure 2 The photon counting detector 04 may include: a plurality of detection units 031 (also referred to as detection pixels) arranged in an array along the channel direction and the slice direction of the photon counting CT device. Each detection unit 041 may receive incident photons.

[0059] The channel direction is Figure 2 The X direction in the layer is Figure 2 The Z direction (i.e. the forward and backward direction of the scanning bed), Figure 2 The Y direction is perpendicular to the X direction and the Z direction respectively.

[0060] The present application provides a counting rate correction method for a photon counting device, which is applied to the photon counting device. The photon counting device includes a detection unit. The photon counting device may be a photon counting X-ray imaging device or a photon counting CT device. For example, the photon counting device may be Figure 1 and Figure 2 Photon counting CT equipment shown. Figure 3 , the method comprising:

[0061] Step 101: Acquire first counting data to be calibrated of a detector unit.

[0062] The photon counting device can scan the scanning object to obtain the first counting data to be corrected of the detection unit. The first counting data includes: the actual counting rate of at least one (for example, multiple) energy intervals (also referred to as energy bins), and the actual counting rate refers to the counting rate in the presence of the pile up effect. The counting rate refers to: the number of photons received by the detection unit per unit time.

[0063] It can be understood that the first counting data may be a first counting vector. Each element in the first counting vector is an actual counting rate in an energy region.

[0064] Step 102: Determine reference counting data from a plurality of second counting data based on the first counting data.

[0065] The photon counting device can calculate the similarity between each second counting data in the plurality of second counting data and the first counting data, and determine the second counting data with a similarity higher than a similarity threshold as the reference counting data, that is, the reference counting data is relatively similar to the first counting data.

[0066] The number of parameter counting data may be one or more. The plurality of second counting data are obtained by the photon counting device scanning a plurality of scanning samples multiple times. The scanning samples and / or scanning parameters of any two scans are different. Each second counting data may include: the actual counting rate of each energy interval in at least one energy interval obtained by scanning the scanning sample. The at least one energy interval is the same as at least one energy interval in the first counting data.

[0067] It can be understood that the second counting data may be a second counting vector. Each element in the second counting vector is an actual counting rate in an energy interval obtained by scanning a scanning sample.

[0068] Step 103: Determine a correction result of the first counting data based on the ideal counting data corresponding to the reference counting data.

[0069] The photon counting device can correct the first counting data based on the ideal counting data corresponding to the reference counting data, so as to correct the actual counting rate of each energy interval in the first counting data to the ideal counting rate without the pile up effect, so as to obtain the correction result of the first counting data. That is, the correction result includes: the first ideal counting rate corresponding to the actual counting rate of each energy interval of the detection unit. The ideal counting data can be understood as the counting rate without the pile up effect.

[0070] In summary, the embodiment of the present application provides a counting rate correction method for a photon counting device. After obtaining the first counting data to be corrected, the method can determine reference counting data that is relatively similar to the first counting data from multiple second counting data, and based on the ideal counting data corresponding to the reference counting data, correct the actual counting rate of each energy interval in the first counting data to the ideal counting rate without the pile up effect. In this way, the correction of the first counting data can be achieved to obtain a more accurate counting rate of each energy interval, thereby ensuring that the quality of the image obtained based on the corrected first counting data is good.

[0071] Moreover, since the multiple second counting data are obtained by the photon counting device performing multiple scans on the scanning sample, that is, the multiple second counting data are the data actually collected by the detection unit, they are closer to the actual counting rate of the detection unit than the counting rate determined by means of a mathematical model. Therefore, the first counting data is corrected based on the ideal counting data corresponding to the reference counting data that is more similar to the first counting data in the multiple second counting data, thereby ensuring that the accuracy of the correction result of the first counting data is higher.

[0072] The present application embodiment takes the first counting data as the first counting vector, the second counting data as the second counting vector, and the at least one energy interval as multiple energy intervals as an example to exemplarily illustrate the flowchart of the counting rate correction method for the photon counting device provided in the present application embodiment. The method can be applied to the photon counting device, see Figure 4 , the method may include:

[0073] Step 201: Acquire multiple second counting vectors of a detection unit.

[0074] In an embodiment of the present application, before scanning the scanned object, the photon counting device may scan multiple scanned samples multiple times, and each scan will obtain a second counting vector, thereby obtaining multiple second counting vectors of the detection unit. Each second counting vector may include: the actual counting rate of each energy interval in the multiple energy intervals obtained by scanning the scanned sample, that is, the length of each second counting vector is the total number of multiple energy intervals. The total number is greater than or equal to 1.

[0075] Among the multiple scans, the scan samples and / or the scan parameters of any two scans are different. The different scan samples may refer to: the materials of the scan samples and / or the thickness of the scan samples are different. The thickness direction of the scan samples may be parallel to the rotation plane of the rack. The different scan parameters may include: the scan doses used in the scans are different, that is, the current of the radiation source is different.

[0076] That is, the photon counting device can scan based on multiple different parameter combinations to obtain multiple second counting vectors. The multiple different parameter combinations can be obtained by arranging and combining the material of the scanned sample, the thickness of the scanned sample, and the scanning parameters.

[0077] For example, assuming that the total number of the multiple energy intervals is 2, the distribution of the multiple second counting vectors of the detection unit can be as follows: Figure 5 shown. Figure 5 The horizontal axis represents the count rate of the first energy interval of the two energy intervals, and the vertical axis represents the count rate of the second energy interval.

[0078] Figure 5 In , each small circle corresponds to a second counting vector, and the horizontal axis value corresponding to each small circle is the actual counting rate of the first energy interval of the second counting vector, and the vertical axis corresponding to the small circle is the actual counting rate of the second energy interval of the second counting vector.

[0079] It can be understood that the photon counting device can obtain as many second counting vectors as possible to ensure that the obtained second counting vectors are relatively rich, thereby ensuring that a second counting vector that is relatively similar to the first counting vector to be corrected can be found from multiple second counting vectors, so as to ensure that the correction result obtained by correcting the first counting vector is more accurate.

[0080] Step 202: Determine an ideal counting vector corresponding to each second counting vector.

[0081] After the photon counting device obtains multiple second counting vectors, for each second counting vector, the photon counting device can determine the ideal counting vector corresponding to the second counting vector. The ideal counting vector of each second counting vector may include: the second ideal counting rate of each energy interval. The second ideal counting rate of each energy interval refers to: the second ideal counting rate of the energy interval in the absence of a pile up effect.

[0082] In an embodiment of the present application, for each second counting vector, the photon counting device can calculate the ideal counting vector corresponding to the second counting vector by a theoretical method or a low-dose fitting method. The theoretical method is based on the Lambert-Beer law to determine the ideal counting vector corresponding to the second counting vector. Specifically, the photon counting device can obtain the energy spectrum of the ray emitted by the ray source of the photon counting device each time the scanning sample is scanned, the attenuation coefficient of each material that the ray passes through before reaching the detection unit, and the path length of each material through which the ray passes. Then, the photon counting device can determine the ideal counting vector corresponding to the second counting vector by the Lambert-Beer law based on the energy spectrum, the attenuation coefficient of each material, and the path length of each material. For example, the photon counting device can bring the energy spectrum, the attenuation coefficient of each material, and the path length of each material into the formula of the Lambert-Beer law to obtain the ideal counting vector corresponding to the second counting vector.

[0083] Each material includes a sample of the scanned sample. The attenuation coefficient of each material can be determined by the attenuation curve of the material.

[0084] The low-dose fitting method is a method based on experimental data. It assumes that at low doses, since the pile up effect is very light, the ideal counting rate at this time is very close to the actual counting rate, and there is a linear relationship between the actual counting rate and the dose. Specifically, a low-dose scan is performed on the scanned sample to obtain the second counting data at different low doses. Under the low-dose scan, the second counting data is equal to the theoretical counting data; based on different low doses and the second counting data corresponding to different low doses, the linear relationship between the scanning dose and the theoretical counting data is obtained; based on the linear relationship, the ideal counting data under the second counting data at other scanning doses is obtained. Other scanning doses may cause the second counting data to have a dose with a pile up effect. Therefore, the photon counting device can obtain the scanning dose of the scanned sample, and then based on the second counting vector, the scanning dose, and the corresponding relationship between the dose and the actual counting rate (i.e., the linear relationship), the ideal counting rate corresponding to the second counting vector can be obtained.

[0085] Optionally, after obtaining the ideal counting vector corresponding to each second counting vector, the photon counting device may record the plurality of second counting vectors and the corresponding ideal counting vectors in a correction table for pile up correction in correspondence.

[0086] Step 203: Obtain a first counting vector to be corrected of the detection unit.

[0087] When it is necessary to obtain a scanned image of a scanned object, the photon counting device can scan the scanned object to obtain a first counting vector to be corrected of the detection unit. The first counting vector includes: an actual counting rate of each energy interval.

[0088] Step 204: Determine a reference count vector from the plurality of second count vectors.

[0089] The photon counting device may determine the similarity between each second counting vector and the first counting vector in the plurality of second counting vectors. Then, the photon counting device may determine the second counting vectors whose similarity is greater than a similarity threshold as reference counting vectors. The number of the reference counting vectors may be one or more.

[0090] In an embodiment of the present application, the photon counting device may determine the distance between each second counting vector and the first counting vector, and then determine the similarity between the second counting vector and the first counting vector based on the distance. The similarity is negatively correlated with the distance. That is, the smaller the distance, the higher the similarity; the larger the distance, the lower the similarity. For example, the similarity may be the inverse of the distance. In other words, the photon counting device may determine the second counting vector whose distance from the first counting vector is less than the distance threshold as the reference counting vector.

[0091] Optionally, the distance between the first count vector and the second count vector may be a Euclidean distance or a Manhattan distance. For example, the distance may be a Euclidean distance.

[0092] It is understandable that in the process of acquiring the reference count vector, the photon counting device can adjust the distance threshold. Specifically, the photon counting device can first determine the initial target area based on the position of the first count vector and the initial distance threshold, and detect whether there is a second count vector in the target area. If the photon counting device determines that there is a second count vector in the target area, each second count vector in the target area can be determined as a reference count vector. If the photon counting device determines that there is no second count vector in the target area, the distance threshold can be increased to expand the target area until a second count vector exists in the target area.

[0093] The initial distance threshold may be pre-stored by the photon counting device. Optionally, the target area may be a circular area with the position of the first counting vector as the center and the distance threshold as the radius.

[0094] Step 205 : Determine a correction result of the first counting vector based on the ideal counting vector corresponding to the reference counting vector.

[0095] The correction result of the first counting vector may include: a first ideal counting rate of each energy interval in the first counting vector.

[0096] In the embodiment of the present application, the photon counting device may determine the correction result of the first counting vector based on the ideal counting vector corresponding to the reference counting vector in multiple ways. The embodiment of the present application takes the following optional implementations as examples to exemplarily illustrate the process of the photon counting device performing step 205:

[0097] In a first optional implementation, the number of reference count vectors is one. The reference count vector has the highest similarity to the first count vector. At this time, the photon counting device can directly determine the ideal count vector corresponding to the reference count vector as the correction result of the first count vector. Specifically, the ideal count vector can include a second ideal count rate for each energy interval. For each energy interval, the photon counting device can determine the second ideal count rate of the energy interval as the first ideal count rate corresponding to the actual count rate of the energy interval in the first count vector.

[0098] In a second optional implementation, there are multiple reference count vectors. The photon counting device can determine a mapping relationship between an ideal count vector and an actual count vector based on multiple reference count vectors and ideal count vectors corresponding to each reference count vector. Then, the photon counting device can determine a correction effect of the first count vector based on the mapping relationship.

[0099] In the embodiment of the present application, the mapping relationship can be represented by a linear transformation matrix. Assuming that the total number of multiple energy intervals is W, that is, the dimensions of the first count vector and each second count vector are W, and assuming that the total number of multiple reference count vectors is S, then the multiple reference count vectors can form a first matrix M1 with a size of S×W, and the ideal count vectors corresponding to the multiple reference count vectors can form a second matrix M2 with a size of S×W.

[0100] Since the reference count vectors are usually located in a small range near the first count vector compared to all the second count vectors, it can be approximately considered that the first matrix and the second matrix satisfy a linear relationship, that is, M2 = T × M1. T is a linear transformation matrix between the first matrix and the second matrix, and the dimension of T is W × W.

[0101] Then, the photon counting device obtains the linear transformation matrix T between the first matrix and the second matrix by the least square method. T can satisfy: T = M2 × M1 -1 , M1 -1 is the pseudo-inverse matrix of the first matrix. Assuming that the first count vector is V1, after correcting the first count vector based on the linear transformation matrix, the correction result V2 obtained can satisfy: V2 = T × V1.

[0102] In a third optional implementation, there are multiple reference count vectors, and the photon counting device may perform weighted summation on the ideal count vectors corresponding to the multiple reference count vectors, thereby obtaining a correction result of the first count vector.

[0103] The weight of the ideal count vector corresponding to each reference count vector is proportional to the similarity between the reference count vector and the first count vector. For example, the weight may be the inverse of the distance between the reference count vector and the first count vector, or may be the square of the inverse.

[0104] For example, Figure 6 A CT image reconstructed without pile up correction is shown. Figure 7 This is a CT image reconstructed by performing pile up correction using the method provided in the embodiment of the present application. Figure 8 A CT image reconstructed using scanning data of an energy-integrating detector is shown. Figure 8 The CT image shown can be used as a standard image.

[0105] contrast Figure 6 , Figure 7 and Figure 8 It can be seen that compared with Figure 6 The CT images shown, Figure 7 The CT image shown is closer Figure 8 It can be seen that the pile up correction by the method provided in the embodiment of the present application can ensure that the count rate after correction is closer to the ideal count rate, thereby ensuring that the quality of the CT image obtained based on the count rate after correction can be significantly improved.

[0106] It is understandable that the above embodiment is an illustrative description using one detection unit as an example. Since the detection units of the detector are independent of each other, the counting rate correction of each detection unit can be implemented by the method described above.

[0107] It is understandable that the order of the steps of the counting rate correction method of the photon counting device provided in the embodiment of the present application can be appropriately adjusted, and the steps can be increased or decreased accordingly according to the situation. For example, step 202 can also be deleted according to the situation. Any technician familiar with the technical field can easily think of a method of change within the technical scope disclosed in this application, which should be included in the protection scope of this application, so it will not be repeated.

[0108] In summary, the embodiment of the present application provides a counting rate correction method for a photon counting device. After obtaining the first counting data to be corrected, the method can determine reference counting data that is relatively similar to the first counting data from multiple second counting data, and based on the ideal counting data corresponding to the reference counting data, correct the actual counting rate of each energy interval in the first counting data to the ideal counting rate without the pile up effect. In this way, the correction of the first counting data can be achieved to obtain a more accurate counting rate of each energy interval, thereby ensuring that the quality of the image obtained based on the corrected first counting data is good.

[0109] Moreover, since the multiple second counting data are obtained by the photon counting device performing multiple scans on the scanning sample, that is, the multiple second counting data are the data actually collected by the detection unit, they are closer to the actual counting rate of the detection unit than the counting rate determined by means of a mathematical model. Therefore, the first counting data is corrected based on the ideal counting data corresponding to the reference counting data that is more similar to the first counting data in the multiple second counting data, thereby ensuring that the accuracy of the correction result of the first counting data is higher.

[0110] The present application embodiment provides a photon counting device, see Fig. 9 The photon counting device includes: a processor 110. The photon counting device also includes: a detection unit. The processor 110 is used to:

[0111] Acquire first counting data to be corrected of the detector unit, the first counting data comprising: an actual counting rate of at least one energy interval;

[0112] Based on the first counting data, determining reference counting data from a plurality of second counting data of the detection unit, each reference counting data having a similarity with the first counting data higher than a similarity threshold, the plurality of second counting data being obtained by scanning the scanning sample by a photon counting device;

[0113] Based on the ideal counting data corresponding to the reference counting data, a correction result of the first counting data is determined, the correction result including a first ideal counting rate corresponding to the actual counting rate of each energy interval.

[0114] Optionally, the number of reference count data is multiple. The processor 110 can be used for:

[0115] Determine a mapping relationship between the ideal counting data and the actual counting data based on the plurality of reference counting data and the ideal counting data corresponding to each reference counting data;

[0116] Based on the mapping relationship, a correction result of the first count data is determined.

[0117] Optionally, the number of reference count data is multiple. The processor 110 can be used for:

[0118] Performing weighted summation on the ideal counting data corresponding to the plurality of reference counting data to obtain a correction result of the first counting data;

[0119] The weight of the ideal counting data corresponding to each reference counting data is proportional to the similarity between the reference counting data and the first counting data.

[0120] Optionally, the number of reference count data is one, and the reference count data has the highest similarity to the first count data. The processor 110 may be configured to:

[0121] Acquire ideal counting data corresponding to the reference counting data, the ideal counting data including: a second ideal counting rate in each energy interval;

[0122] The second ideal counting rate in each energy interval is determined as the first ideal counting rate corresponding to the actual counting rate in the energy interval in the first counting data.

[0123] Optionally, the processor 110 may also be configured to:

[0124] Before determining the reference counting data from the plurality of second counting data of the detection unit, determining the distance between each second counting data and the first counting data;

[0125] Based on the distance, the similarity between the second count data and the first count data is determined, and the similarity is negatively correlated with the distance.

[0126] Optionally, the number of scan samples is multiple. The processor 110 can also be used to

[0127] Before determining the reference counting data from the plurality of second counting data of the detection unit, scanning the plurality of scanning samples to obtain the plurality of second counting data;

[0128] The scanning samples of any two scans are different, and / or the scanning parameters are different.

[0129] Optionally, the photon counting device further includes: a ray source. The processor 110 can also be used for:

[0130] Obtaining the energy spectrum of the ray emitted by the ray source, the attenuation coefficient of each material that the ray passes through before reaching the detection unit, and the path length of each material that the ray passes through each time the scanning sample is scanned;

[0131] Determining ideal count data corresponding to the second count data based on the energy spectrum, the attenuation coefficient of each material, and the path length of each material;

[0132] Alternatively, obtaining a scan dose when scanning a scan sample;

[0133] Based on the second counting data, the scanning dose, and the corresponding relationship between the dose and the actual counting rate, ideal counting data corresponding to the second counting data is determined.

[0134] In summary, the embodiment of the present application provides a photon counting device, which, after acquiring the first counting data to be corrected, can determine reference counting data that is relatively similar to the first counting data from a plurality of second counting data, and based on the ideal counting data corresponding to the reference counting data, correct the actual counting rate of each energy interval in the first counting data to the ideal counting rate without the pile up effect. In this way, the first counting data can be corrected to obtain a more accurate counting rate of each energy interval, thereby ensuring that the quality of the image obtained based on the corrected first counting data is good.

[0135] Moreover, since the multiple second counting data are obtained by the photon counting device performing multiple scans on the scanning sample, that is, the multiple second counting data are the data actually collected by the detection unit, they are closer to the actual counting rate of the detection unit than the counting rate determined by means of a mathematical model. Therefore, the first counting data is corrected based on the ideal counting data corresponding to the reference counting data that is more similar to the first counting data in the multiple second counting data, thereby ensuring that the accuracy of the correction result of the first counting data is higher.

[0136] like Fig. 9 As shown, the photon counting device 100 includes: a processor 110 and a memory 130. The processor 110 and the memory 130 are connected, such as through a bus 120. Optionally, the photon counting device 100 may also include a transceiver 140. It should be noted that in actual applications, the transceiver 140 is not limited to one, and the structure of the photon counting device 100 does not constitute a limitation on the embodiments of the present application.

[0137] The processor 110 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor 110 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0138] The bus 120 may include a path to transmit information between the above components. The bus 120 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 120 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig. 9 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0139] The memory 130 is used to store a computer program corresponding to the counting rate correction method of the photon counting device of the above embodiment of the present application, and the computer program is controlled and executed by the processor 110. The processor 110 is used to execute the computer program stored in the memory 130 to implement the content shown in the above method embodiment.

[0140] The present application embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the counting rate correction method of the photon counting device provided in the above method embodiment is implemented. Figure 3 or Figure 4 The method shown.

[0141] The present application embodiment provides a computer program product, which includes a computer program or computer instructions, and when the computer program or computer instructions are executed by a processor, a counting rate correction method for a photon counting device as provided in the above method embodiment is implemented. Figure 3 or Figure 4 The method shown.

[0142] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0143] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0144] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0145] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0146] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0147] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A counting rate correction method for a photon counting device, characterized in that: The photon counting device comprises: a detection unit; the method comprises: Acquire first counting data to be corrected of the detector unit, the first counting data comprising: an actual counting rate of at least one energy interval; Based on the first counting data, determining reference counting data from a plurality of second counting data of the detection unit, each of the reference counting data having a similarity with the first counting data higher than a similarity threshold, the plurality of second counting data being obtained by the photon counting device scanning a scanning sample; Based on the ideal counting data corresponding to the reference counting data, a correction result of the first counting data is determined, the correction result including a first ideal counting rate corresponding to the actual counting rate of each of the energy intervals.

2. The method according to claim 1, characterized in that The number of the reference count data is multiple; based on the ideal count data corresponding to the reference count data, determining the correction result of the first count data includes: Determine a mapping relationship between the ideal counting data and the actual counting data based on the plurality of reference counting data and the ideal counting data corresponding to each of the reference counting data; Based on the mapping relationship, a correction result of the first counting data is determined.

3. The method according to claim 1, characterized in that The number of the reference count data is multiple; based on the ideal count data corresponding to the reference count data, determining the correction result of the first count data includes: Performing weighted summation on the ideal counting data corresponding to the plurality of reference counting data to obtain a correction result of the first counting data; The weight of the ideal counting data corresponding to each of the reference counting data is proportional to the similarity between the reference counting data and the first counting data.

4. The method according to claim 1, characterized in that: The number of the reference count data is one, and the reference count data has the highest similarity with the first count data; Determining a correction result of the first counting data based on the ideal counting data corresponding to the reference counting data includes: Acquire ideal counting data corresponding to the reference counting data, the ideal counting data comprising: a second ideal counting rate of each of the energy intervals; The second ideal counting rate in each of the energy intervals is determined as the first ideal counting rate corresponding to the actual counting rate in the energy interval in the first counting data.

5. The method according to any one of claims 1 to 4, characterized in that: Before determining the reference counting data from the plurality of second counting data of the detection unit, the method further comprises: determining a distance between each of the second counting data and the first counting data; Based on the distance, a similarity between the second count data and the first count data is determined, and the similarity is negatively correlated with the distance.

6. The method according to any one of claims 1 to 4, characterized in that: The number of the scan samples is multiple; before determining the reference counting data from the multiple second counting data of the detection unit, the method further includes: Scanning a plurality of the scan samples to obtain a plurality of the second counting data; The scan samples of any two scans are different, and / or the scan parameters are different.

7. The method according to any one of claims 1 to 4, characterized in that: The photon device further includes: a ray source; before determining a correction result of the first counting data based on the ideal counting data corresponding to the reference counting data, the method further includes: Acquire the energy spectrum of the ray emitted by the ray source each time the scanning sample is scanned, the attenuation coefficient of each material that the ray passes through before reaching the detection unit, and the path length of each material that the ray passes through; determining ideal count data corresponding to the second count data based on the energy spectrum, the attenuation coefficient of each of the materials, and the path length of each of the materials; Alternatively, a low-dose scan is performed on the scanned sample to obtain second counting data at different low doses, wherein the second counting data is equal to the theoretical counting data under the low-dose scan; Based on different low doses and second counting data corresponding to the different low doses, a linear relationship between the scanning dose and the theoretical counting data is obtained; Based on the linear relationship, ideal count data under second count data under other scanning doses are acquired.

8. A photon counting device, characterized in that The photon counting device comprises: a detection unit and a processor; the processor is used for: Acquire first counting data to be corrected of the detector unit, the first counting data comprising: an actual counting rate of at least one energy interval; Based on the first counting data, determining reference counting data from a plurality of second counting data of the detection unit, each of the reference counting data having a similarity with the first counting data higher than a similarity threshold, the plurality of second counting data being obtained by the photon counting device scanning a scanning sample; Based on the ideal counting data corresponding to the reference counting data, a correction result of the first counting data is determined, the correction result including a first ideal counting rate corresponding to the actual counting rate of each of the energy intervals.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program or a computer instruction, and when the computer program or the computer instruction is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images