Method and apparatus for quality evaluation and control of motion information in pet scan process

Abstract

The application provides a quality evaluation and control method, device and system of motion information in a PET scanning process. The quality evaluation method collects list mode data and patient motion information according to a preset sampling frequency; generates to-be-evaluated position information of a region of interest at each sampling time according to the list mode data and the patient motion information; and finally obtains a quality evaluation result according to a preset quality evaluation index and the to-be-evaluated position information within a preset sampling time period. The quality control method of the application performs secondary correction on the patient motion information and / or the list mode data according to the distribution of the to-be-evaluated position information within the preset sampling time period when the quality evaluation result does not meet a preset quality requirement. The application can objectively evaluate the quality of motion information in the PET scanning process and correct the patient motion information and / or the list mode data when necessary, thereby improving the reconstruction efficiency and quality of a PET image.

Description

Technical Field

[0001] This invention relates to the field of digital medical technology, and in particular to a method for quality evaluation and control of motion information during PET scanning, a PET data processing device, and a PET imaging system. Background Technology

[0002] During PET scans, the scan time is relatively long, and patients inevitably move during the process. If PET image reconstruction is performed directly from the acquired scan data, artifacts may appear, resulting in poor image quality and hindering diagnosis. To improve the imaging quality of medical images and obtain high-quality PET images, current technologies typically correct motion information during the PET scan. However, since quality control of motion correction mainly relies on subjective evaluation or quantitative regional assessment of the reconstructed image by professionals, it is not only resource-intensive and inefficient, but also cannot correct images that do not meet diagnostic needs. This necessitates a rescan, which not only reduces PET image reconstruction efficiency and further wastes human and material resources, but also places an unnecessary scanning burden on the patient, negatively impacting their physical and mental health.

[0003] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies that lack direct and objective evaluation of motion correction information during PET scanning. This invention provides a method for quality evaluation and control of motion information during PET scanning, a PET data processing device, and a PET imaging system. These methods allow for objective evaluation of motion correction information and, when necessary, correction of patient data, thereby improving the efficiency and quality of PET scanning and saving human and material costs.

[0005] To achieve the above objectives, the present invention provides a method for evaluating the quality of motion information during PET scanning, comprising:

[0006] During a PET scan, list pattern data of the region of interest and patient motion information are collected according to a preset sampling frequency.

[0007] At each sampling time, the response line in the list pattern data is relocated using the patient motion information, and the location information of the region of interest to be evaluated at that sampling time is generated based on the relocated response line.

[0008] Based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period, a quality evaluation result of the patient's motion information is generated.

[0009] Optionally, the location information to be evaluated includes the centroid coordinates and / or rotation scale of the region of interest;

[0010] Before obtaining the centroid coordinates and / or rotation scale of the region of interest, the process also includes:

[0011] Each response line after relocation at the sampling time is back-projected into the region of interest;

[0012] Sensitivity correction is performed on each back-projection point after back-projection, and the centroid coordinates and / or rotation scale of the region of interest at the sampling time are obtained based on the sensitivity-corrected back-projection points.

[0013] Optionally, the centroid coordinates of the region of interest at this sampling time can be obtained through the following steps:

[0014] Based on all the back-projection points after the sensitivity correction, a point cloud map of the back-projection points at the sampling time is generated;

[0015] Based on the point cloud map, the centroid coordinates of the region of interest are calculated.

[0016] Optionally, the rotation scale of the region of interest at that sampling time can be obtained through the following steps:

[0017] For each of the back-projection points after sensitivity correction, the second-order rotational inertia matrix is ​​calculated based on the three-dimensional position coordinates of the back-projection point at the sampling time and the sensitivity correction value corresponding to the back-projection point.

[0018] The rotation matrix is ​​calculated based on the second-order moment of inertia matrix.

[0019] The rotation matrix is ​​converted into Euler angles in the X, Y, and Z directions to obtain the rotation scale of the region of interest.

[0020] Optionally, generating a quality evaluation result for the patient's motion information based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period includes:

[0021] The distribution stability of the location information to be evaluated is statistically analyzed according to the chronological order of the sampling times.

[0022] The quality evaluation result of the patient's motion information is given based on the deviation between the distribution stability of the location information to be evaluated and the preset evaluation threshold.

[0023] To achieve the above objectives, the present invention also provides a method for quality control of motion information during PET scanning, comprising:

[0024] The quality assessment results of the patient's motion information are obtained by using any of the quality assessment methods described above;

[0025] Determine whether the quality evaluation result meets the preset quality requirements: if not, then correct the patient movement information and / or list pattern data according to the distribution of the location information to be evaluated within the preset sampling time period.

[0026] Optionally, the step of correcting the patient's motion information based on the distribution of the location information to be evaluated within a preset sampling time period includes:

[0027] According to the first preset index, if it is determined that the distribution of the location information to be evaluated has a discontinuity within the preset sampling time period, the following steps are used to correct the patient's motion information:

[0028] Acquire each first sampling time point at the location where the location information to be evaluated occurs within the preset sampling time period; and divide the patient's motion information into several segments based on the first sampling time points;

[0029] For each segment of the patient motion information corresponding to the collected list pattern data, PET image reconstruction without attenuation correction is performed to obtain a reference PET image;

[0030] Each frame of the reference PET image except the first frame is registered to the first frame of the reference PET image to obtain the registration information corresponding to each frame of the reference PET image except the first frame;

[0031] Based on the registration information, the patient motion information is corrected to obtain the corrected patient motion information.

[0032] Optionally, the step of correcting the patient's motion information based on the distribution of the location information to be evaluated within a preset sampling time period includes:

[0033] According to the second preset index, if it is determined that there are outliers in the distribution of the location information to be evaluated within the preset sampling time period, the following steps are used to correct the list pattern data:

[0034] According to the second preset index, obtain the second sampling time point of the evaluation location information of each outlier;

[0035] Remove all the list pattern data collected at the second sampling time point to obtain the corrected list pattern data.

[0036] To achieve the above objectives, the present invention also provides a PET data processing apparatus, comprising: a data acquisition unit and a unit for acquiring location information to be evaluated, and at least one of an evaluation result acquisition unit and a correction unit; wherein,

[0037] The data acquisition unit is configured to acquire list-pattern data of the region of interest and patient motion information at a preset sampling frequency during PET scanning.

[0038] The unit for acquiring location information to be evaluated is configured to, at each sampling time, use the patient motion information to relocate the response line in the list pattern data, and generate the location information to be evaluated of the region of interest at that sampling time based on the relocated response line.

[0039] The evaluation result acquisition unit is configured to generate a quality evaluation result of the patient's motion information based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period.

[0040] The correction unit is configured to determine whether the quality evaluation result meets the preset quality requirements; if not, it corrects the patient movement information and / or the list pattern data according to the distribution of the location information to be evaluated within the preset sampling time period.

[0041] To achieve the above objectives, the present invention also provides a PET imaging system, the PET imaging system including a processor and a memory, the memory storing a computer program, the computer program being executed by the processor to implement the quality evaluation method for motion information during PET scanning as described in any of the preceding claims to evaluate patient motion information and / or the quality control method for motion information during PET scanning as described in any of the preceding claims to correct patient motion information and / or list pattern data.

[0042] Compared with existing technologies, the method for quality evaluation and control of motion information during PET scanning, the PET data processing device, and the PET imaging system provided by this invention have the following advantages:

[0043] The present invention provides a method for evaluating the quality of motion information during PET scanning. During the PET scan, firstly, list pattern data of the region of interest (ROI) and patient motion information are collected at a preset sampling frequency. At each sampling moment, the response lines in the list pattern data are repositioned using the patient motion information, and the location information of the ROI to be evaluated at that sampling moment is generated based on the repositioned response lines. Finally, a quality evaluation result of the patient motion information is generated based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period. Therefore, the method for evaluating the quality of motion information during PET scanning provided by the present invention, by collecting list pattern data of the ROI and patient motion information at a preset sampling frequency (e.g., 1 second) within a preset sampling time period (preferably the entire PET scan period, e.g., 40 minutes), can continuously (throughout the entire preset sampling time period) and with finer granularity (at the same sampling frequency) evaluate the quality of patient motion information. The evaluation location information (including but not limited to the centroid coordinates and rotation scale of the region of interest) is generated by simplified back projection of all response lines within a preset sampling time period, which is highly efficient. Furthermore, the quality evaluation result is obtained based on preset quality evaluation indicators and the evaluation location information within the preset sampling time period, which is not only highly reliable, but also requires no human intervention throughout the process, ensuring the objectivity and consistency of the quality evaluation result. This significantly saves manpower and material costs and has high quality evaluation efficiency.

[0044] Furthermore, the quality control method for motion information during PET scanning provided by this invention first employs the aforementioned quality evaluation method to obtain a quality evaluation result for the patient's motion information; then, when the quality evaluation result does not meet preset quality requirements, the patient's motion information and / or list pattern data are corrected based on the distribution of the location information to be evaluated within a preset sampling time period. Thus, the quality control method for motion information during PET scanning provided by this invention corrects patient motion information and / or list pattern data that do not meet preset quality requirements, thereby reconstructing the PET image of the region of interest using the corrected patient motion information and / or list pattern data. This achieves intelligent reconstruction of PET images while ensuring the quality of the reconstructed PET images, realizing an end-to-end process and saving manpower and material costs.

[0045] Since the PET data processing device and PET imaging system provided by this invention belong to the same inventive concept as the quality evaluation method and / or quality control method for motion information during PET scanning provided by this invention, they have at least the same beneficial effects, and will not be described in detail here. Attached Figure Description

[0046] Figure 1This is a schematic diagram of the overall process of the method for evaluating the quality of motion information during PET scanning provided in Embodiment 1 of the present invention;

[0047] Figure 2 This is a schematic diagram illustrating the distribution of the centroid coordinates of the region of interest in the X, Y, and X directions over time, as a specific example of Embodiment 1 of the present invention.

[0048] Figure 3 This is a schematic diagram of the overall process of the quality control method for motion information during PET scanning provided in Embodiment 2 of the present invention;

[0049] Figure 4 This is a block diagram of the PET data processing device provided in Embodiment 3 of the present invention;

[0050] Figure 5 This is a structural block diagram of the PET imaging system provided in Embodiment 4 of the present invention.

[0051] The accompanying figure is labeled as follows:

[0052] Data acquisition unit-110, location information acquisition unit to be evaluated-120, evaluation result acquisition unit-130, correction unit-140;

[0053] Processor-210, communication interface-220, memory-230, communication bus-240, imaging device-250, terminal-260, network-270. Detailed Implementation

[0054] The following detailed description, in conjunction with the accompanying drawings, provides a further detailed explanation of the method for quality evaluation and control of motion information during PET scanning, the PET data processing device, and the PET imaging system proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the purpose of the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read them, and are not intended to limit the implementation conditions of this invention. Any modifications to the structure, changes in proportions, or adjustments to the size, provided that the effects and objectives achieved by this invention are the same or similar, should still fall within the scope of the technical content disclosed in this invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific application and usage environment. Furthermore, in the embodiments described below, the same reference numerals are sometimes used across different figures to denote the same parts or parts having the same function, omitting repeated descriptions. In this specification, similar reference numerals and letters are used to denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures. Additionally, if the methods described herein comprise a series of steps, and the order of these steps presented herein is not necessarily the only possible order in which these steps can be performed, some described steps may be omitted and / or other steps not described herein may be added to the method.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The singular forms “a,” “an,” and “the” include plural objects. The term “or” is generally used to mean “and / or,” the term “several” is generally used to mean “at least one,” and the term “at least two” is generally used to mean “two or more.” Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0056] The core idea of ​​this invention is to provide a method for quality evaluation and control of motion information during PET scanning, a PET data processing device, and a PET imaging system, so as to objectively evaluate patient motion information and correct patient motion information and / or list pattern data when necessary, thereby improving the efficiency and quality of PET scanning imaging and saving manpower and material costs.

[0057] Before specifically introducing the method for quality evaluation and control of motion information during PET scanning, the PET data processing device, and the PET imaging system provided by the present invention, it should be noted that the method for quality evaluation and control of motion information during PET scanning provided by the present invention can be applied to the PET data processing device and / or PET imaging system of the embodiments of the present invention. The PET data processing device can be a personal computer, a mobile terminal, etc., and the mobile terminal can be a mobile phone, a tablet computer, or other hardware device with various operating systems.

[0058] Example 1

[0059] This embodiment provides a method for evaluating the quality of motion information during PET scanning. Please refer to [link / reference]. Figure 1 This diagram schematically illustrates the overall process flow of the motion information quality assessment method during PET scanning provided in this embodiment. From Figure 1 As can be seen, the method for evaluating the quality of motion information during PET scanning provided in this embodiment includes:

[0060] S100: During a PET scan, collect list pattern data of the region of interest and patient motion information according to a preset sampling frequency;

[0061] S200: At each sampling time, the response line in the list pattern data is repositioned using the patient motion information, and the location information of the region of interest to be evaluated at that sampling time is generated based on the repositioned response line.

[0062] S300: Generate a quality evaluation result for the patient's motion information based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period.

[0063] The method for evaluating the quality of motion information during PET scanning provided in this embodiment collects list-pattern data of the region of interest and patient motion information at a preset sampling frequency (e.g., 1 second) within a preset sampling time period (preferably the entire PET scan period, such as 40 minutes). This allows for continuous (the entire preset sampling time period) and finer-grained (same as the sampling frequency) evaluation of the quality of patient motion information. The method generates the location information to be evaluated (including but not limited to the centroid coordinates and rotation scale of the region of interest) by simplified back-projection of all response lines within the preset sampling time period, resulting in high generation efficiency. Furthermore, the quality evaluation results are obtained based on preset quality evaluation indicators and the location information to be evaluated within the preset sampling time period. This not only ensures high reliability but also eliminates the need for manual intervention, guaranteeing the objectivity and consistency of the quality evaluation results. It significantly saves manpower and material costs and has high quality evaluation efficiency.

[0064] Specifically, as those skilled in the art will understand, the imaging principle of a PET imaging system is as follows: Before a PET scan, a radioactively labeled drug / tracer is injected into the patient's body. During the PET scan, the drug / tracer decays and emits positrons, which annihilate with surrounding electrons to produce a pair of photons emitted in opposite directions. If both photons are detected simultaneously by the detectors of the PET imaging system, the radioactive isotope is considered to be on the line connecting the two detectors that captured the photons; this line is called the response line (LOR). The collection of all response lines during the PET scan constitutes the raw data for reconstructing the PET image, also known as list mode data. Simultaneously, a position tracking device collects patient motion information and sends the collected patient motion information to the imaging equipment of the PET imaging system. PET imaging systems typically employ continuous scanning mode so that the imaging equipment can reconstruct PET images (such as 3D medical images) based on the list mode data and the patient motion information.

[0065] It should be specifically noted that the list-mode data may be data without Time-of-Flight (TOF) information or data containing TOF information. This invention does not impose any limitations on this. As those skilled in the art will understand, if the list-mode data contains TOF information, then in the subsequent back-projection process, only the center point of the TOF box needs to be projected for each LOR to represent the LOR. Furthermore, the patient motion information may be rigid motion information based on six degrees of freedom, such as head movement or limb movement, or non-rigid motion information such as blood flow, heartbeat, or respiratory movement; in addition, the patient motion information may be motion information recorded by hardware devices or motion information estimated based on scan data using software algorithms.

[0066] It should be noted that the method for evaluating the quality of motion information during PET scanning provided in this embodiment has broad applicability. Specifically, firstly, the method for evaluating the quality of motion information during PET scanning provided by this invention does not impose any limitations on the PET imaging system and the reagent / tracer. The PET imaging system can be an emission computed tomography (ECT) device, a positron emission tomography (PET) device, a single photon emission computed tomography (SPECT) device, a multimodal device, or any combination thereof. Exemplary multimodal devices may include CT-PET imaging systems, MR-PET imaging systems, etc. Secondly, the method for evaluating the quality of motion information during PET scanning provided by this invention does not impose any limitations on the reagent / tracer. For example, in some embodiments, the reagent / tracer may include one or more radioactive elements such as carbon (¹¹C), nitrogen (¹³N), oxygen (¹⁵O), and fluorine (¹⁸F). In some embodiments, when the SPPET scanning system is selected as the PET imaging system, the tracer used may be one or more of technetium-99m, iodine-123, indium-111, and iodine-131. Exemplarily, the tracer can be a single tracer such as 18F-FDG, 18F-EF5, or 8F-ML-10; or a multi-tracer for dynamic scanning, such as dual tracers like 18F-FDG and 18F-FLT, or 11C-ACT and 18F-FDG. Furthermore, the present invention does not limit the acquisition device for collecting patient motion information. As mentioned above, the acquisition device includes, but is not limited to, scanners, trackers, and / or other image recording devices, and can also be a software algorithm. Further, the position tracking device can be a component of the PET imaging system or a separate device communicatively connected to the PET imaging system.

[0067] Furthermore, the preset sampling time period is preferably the entire PET scan period (usually 20 to 40 minutes), and the sampling frequency is preferably once per second. As those skilled in the art will understand, this embodiment does not impose any restrictions on the sampling frequency and the preset sampling time period; for example, the sampling frequency can also be other values ​​such as once every 0.5 seconds or once every 2 seconds.

[0068] More specifically, in step S200, the location information to be evaluated includes, but is not limited to, at least one of the centroid coordinates and rotation scale of the region of interest at the sampling time. However, as a preferred embodiment, the location information to be evaluated of the region of interest at the sampling time is preferably motion information with six degrees of freedom: translational degrees of freedom and rotational degrees of freedom (rotation angles around the X, Y, and Z coordinate axes, respectively) in the X, Y, and Z rectangular coordinate axes.

[0069] It should be noted that, in step 200, the repositioning of the response lines in the list pattern data using the patient motion information is preferably performed by repositioning the response lines in the list pattern data to the patient reference position. Specifically, the present invention does not limit the patient reference position. For example, in some embodiments, the patient position at the start of the scan (which can also be understood as the position when the patient has not moved) can be used as the patient reference position; in other embodiments, any position within the PET system can be specified as the patient reference position.

[0070] Before obtaining the centroid coordinates and / or rotation scale of the region of interest at the sampling time, the process further includes:

[0071] S201: Back-project each response line after relocation at the sampling time into the region of interest;

[0072] S202: Perform sensitivity correction on each back-projection point after back-projection, and obtain the centroid coordinates and / or rotation scale of the region of interest at the sampling time based on the sensitivity-corrected back-projection points.

[0073] Therefore, the quality assessment method for motion information during PET scanning provided in this example performs backprojection on the repositioned response lines within the region of interest (ROI) and then performs sensitivity correction on the backprojected points. This allows for faster acquisition of the centroid coordinates and / or rotation scale of the ROI at each sampling moment within a preset sampling time period by performing simplified backprojection on all response lines, thus improving the efficiency of quality assessment. Furthermore, sensitivity correction improves the calculation accuracy of the centroid coordinates and / or rotation scale of the ROI at that sampling moment. It should be noted that for more detailed information on repositioning, backprojection, and sensitivity correction, please refer to the relevant descriptions in the prior art for understanding; these will not be elaborated upon here.

[0074] More specifically, in one exemplary embodiment, the centroid coordinates of the region of interest at that sampling time are obtained through the following steps:

[0075] S210: Generate a point cloud map of the back projection points at the sampling time based on all the back projection points after the sensitivity correction;

[0076] S220: Calculate the centroid coordinates of the region of interest based on the point cloud map.

[0077] Therefore, the quality evaluation method for motion information during PET scanning provided in this example generates the location information to be evaluated (including but not limited to the centroid coordinates and rotation scale of the region of interest) by simplifying back projection of all response lines within a preset sampling time period, which is highly efficient. Furthermore, the quality evaluation result is obtained based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period, which is not only highly reliable, but also requires no manual intervention throughout the process, laying a good foundation for the objectivity and consistency of the quality evaluation result.

[0078] It should be noted that, as a preferred embodiment, if the movement of the organ tissue (e.g., head) in the region of interest is rigid, the centroid coordinates of the region of interest in the X, Y, and Z directions are preferably the average of the coordinate values ​​of the organ tissue in the X, Y, and Z directions. If the movement of the organ tissue (e.g., blood) in the region of interest is flexible, the centroid coordinates obtained from the contour of the organ tissue obtained from the point cloud map are used as the centroid coordinates of the region of interest. Furthermore, as those skilled in the art will understand, detailed information on how to reconstruct the point cloud map to obtain the centroid coordinates can be found in the prior art and will not be repeated here.

[0079] In one exemplary embodiment, the rotation scale (rotation angles about the X, Y, and Z coordinate axes, respectively) of the region of interest at the sampling time is obtained through the following steps:

[0080] S221: For each of the back-projection points after sensitivity correction, the second-order rotational inertia matrix is ​​calculated based on the three-dimensional position coordinates of the back-projection point at the sampling time and the sensitivity correction value corresponding to the back-projection point.

[0081] S222: Calculate the rotation matrix based on the second-order moment of inertia matrix;

[0082] S223: Convert the rotation matrix into Euler angles in the X, Y and Z directions to obtain the rotation scale of the region of interest.

[0083] Specifically, in step S221, at sampling time t, the second-order rotational inertia matrix of the i-th projection point is calculated using the following formula:

[0084]

[0085] In the formula,

[0086]

[0087]

[0088]

[0089] x i ,y i ,z i Let s be the coordinates of the centroid of the i-th projection point in the X, Y, and Z directions, respectively. i This is the sensitivity correction value corresponding to the i-th projection point. As those skilled in the art will understand, the sensitivity correction value is a known value, determined by the PET imaging system itself.

[0090] More specifically, in step S222, calculating the rotation matrix based on the second-order moment of inertia matrix includes obtaining the rotation matrix R through singular value decomposition:

[0091] I t =R T IR

[0092] In the formula, I is a third-order identity matrix, and t is the sampling time.

[0093] In one preferred embodiment, step S300, generating a quality evaluation result for the patient's motion information based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period, includes:

[0094] S310: Calculate the distribution stability of the location information to be evaluated according to the order in which the sampling times occur;

[0095] S320: Based on the deviation between the distribution stability of the location information to be evaluated and the preset evaluation threshold, the quality evaluation result of the motion information during the PET scan is given.

[0096] Therefore, the quality evaluation method for motion information during PET scanning provided in this embodiment, wherein the quality evaluation result is obtained based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period, is not only highly reliable, but also requires no human intervention throughout the process, ensuring the objectivity and consistency of the quality evaluation result, and can significantly save manpower and material costs, thus having high quality evaluation efficiency.

[0097] As those skilled in the art will understand, when the duration of the preset sampling time period (e.g., greater than 20 minutes) is much greater than the preset sampling frequency (e.g., 1 second), the distribution of the location information to be evaluated should theoretically tend to be stable, and as time goes by, the patient's actual motion information forms a continuous broken line that is approximately straight; that is, the stability of the distribution of the location information to be evaluated can indirectly reflect the similarity (quantitative indicator) between the collected patient motion information and the patient's actual motion information.

[0098] Specifically, in one exemplary embodiment, the six degrees of freedom of the region of interest are evaluated, including the centroid coordinates in the X, Y, and Z directions and the rotation angles in the X, Y, and Z directions. For ease of understanding and to avoid redundancy, the following explanation uses the centroid coordinates of the region of interest in the X, Y, and Z directions as an example. For the rotation angles of the region of interest in the X, Y, and Z directions, please refer to the relevant explanation of the centroid coordinates of the region of interest in the X, Y, and Z directions for a more appropriate understanding; further explanation will not be provided here.

[0099] Specifically, see Figure 2 It schematically illustrates the change of the centroid coordinates of the region of interest in the X, Y, and Z directions over time in one specific example. Figure 2 In the diagram, the COD curve represents the centroid coordinate curve of the region of interest acquired at various time points; the MCCOD curve represents the corresponding motion-corrected centroid coordinate curve. From... Figure 2It can be seen that, along the X-axis, although the centroid coordinates of the region of interest acquired around the 41st and 51st minutes showed significant jumps, after motion correction, the centroid coordinates of the region of interest remained relatively stable along the X-axis (basically parallel to the time axis). Similarly, along the Y-axis, although there were breaks between the 44th and 50th minutes and at the 54th minute, the centroid coordinates of the region of interest remained relatively stable along the Y-axis (basically parallel to the time axis). Along the Z-axis, although there were breaks between the 45th and 50th minutes and at the 54th minute, and a significant jump occurred at the 48th minute, the centroid coordinates of the region of interest remained relatively stable along the Z-axis (basically parallel to the time axis). Therefore, Figure 2 After motion correction, the centroid coordinates of the region of interest remain basically stable, meeting the expected standards.

[0100] It should be noted that those skilled in the art should understand that Figure 2 This is merely an illustrative example to facilitate understanding of the invention and is not intended to limit the invention. In specific implementations, the stability of the distribution of the location information to be evaluated can be measured using quantitative indicators, including but not limited to range, mean deviation, and standard deviation.

[0101] In summary, the quality evaluation method for motion information during PET scanning provided in this embodiment realizes an end-to-end process without human intervention, ensuring the objectivity and consistency of the quality evaluation results. Moreover, it can significantly save manpower and material costs and has high quality evaluation efficiency.

[0102] Example 2

[0103] This example provides a method for quality control of motion information during PET scanning. For details, please refer to [link to relevant documentation]. Figure 3 ,from Figure 3 As can be seen, the quality control method for motion information during PET scanning provided in this example includes the following steps:

[0104] Step A: Using the quality assessment method for motion information during PET scanning as described in Embodiment 1 above, the quality assessment result of the patient's motion information is obtained;

[0105] Step B: Determine whether the quality evaluation result meets the preset quality requirements: If not, then correct the patient movement information and / or list pattern data according to the distribution of the location information to be evaluated within the preset sampling time period.

[0106] The quality control method for motion information during PET scanning provided in this example corrects patient motion information and / or list pattern data that do not meet preset quality requirements. As a result, the PET image of the region of interest is reconstructed using the corrected patient motion information and / or list pattern data. This method can achieve intelligent reconstruction of PET images while ensuring the quality of the reconstructed PET images, realizing an end-to-end process and thus saving manpower and material costs.

[0107] Specifically, the detailed process for obtaining the quality assessment result of the patient's motion information in step A is described in Embodiment 1 above, and will not be elaborated further here to avoid redundancy. Furthermore, as those skilled in the art will understand, when the quality assessment result meets the preset quality requirements, there is no need to correct the patient's motion information; the imaging device of the PET imaging system can reconstruct the PET image (e.g., a 3D medical image) based on the list pattern data and the patient's motion information.

[0108] Furthermore, those skilled in the art should understand that in the quality evaluation method for motion information during PET scanning provided by this invention, the preset quality evaluation index refers to a dimension for evaluating the quality of motion information during PET scanning. The preset quality evaluation index includes, but is not limited to, jumps and tomographic breaks in motion information, and this invention does not limit these. The quality evaluation result refers to the degree of deviation between the distribution stability of the location information to be evaluated and the preset evaluation threshold under a determined quality evaluation dimension. For example, in some embodiments, the preset quality evaluation index is the degree of jump in the location information to be evaluated (see details...). Figure 2(To aid understanding), for example, the evaluation result for the location information to be evaluated if the distance between it and the patient's reference position is less than a preset evaluation threshold is considered as no jump. The evaluation result for the location information to be evaluated if the distance between it and the patient's reference position is greater than or less than a preset evaluation threshold includes the location information to be evaluated having a jump and the corresponding jump variable. Furthermore, if the jump variable exceeds the preset quality requirements, the patient's motion information needs to be corrected. It should be particularly noted that those skilled in the art should understand that there are various reasons why the location information to be evaluated may not meet the preset quality requirements. Obviously, finding and analyzing the causes, and correctly correcting the collected patient motion information, has always been one of the important research topics for those skilled in the art. To provide an objective quality assessment of motion information during PET scans, the inventors of this invention, through extensive research and continuous practical application, discovered that the following two main reasons cause the evaluated positional information (indirectly reflecting the inability of corrections to patient motion information to meet the requirements of PET image reconstruction) to fail to meet preset quality requirements: First, motion markers used for positioning on the patient slip during scanning, causing jumps in the acquired patient motion information (e.g., after being detected and then returned to their original position), resulting in gaps in the acquired patient motion information and inconsistencies in the acquired reference position. Second, large movements by the patient during scanning cause interference to the acquired patient motion information for a short period (e.g., less than 1 minute), leading to significant abrupt changes in the acquired patient motion information within a short time.

[0109] Based on the above research, to address the issue of inconsistent patient motion information leading to substandard evaluation location information, the inventors of this invention employ different correction methods to refine patient motion information and / or list-pattern data. Detailed explanations are as follows:

[0110] In one exemplary embodiment, step B, which involves correcting the patient's motion information based on the location information to be evaluated within a preset sampling time period, specifically includes: if, based on a first preset index, it is determined that the distribution of the location information to be evaluated has a discontinuity within the preset sampling time period, then the following steps are used to correct the patient's motion information:

[0111] B12: Obtain each first sampling time point at the location where the location information to be evaluated occurs within the preset sampling time period; and divide the patient's motion information into several segments based on the first sampling time points;

[0112] B13: For each segment of the patient motion information corresponding to the collected list pattern data, perform PET image reconstruction without attenuation correction to obtain a reference PET image;

[0113] B14: Register each of the reference PET images except the first frame to the first frame of the reference PET image, and obtain the registration information corresponding to each of the reference PET images except the first frame;

[0114] B15: Based on the registration information, the patient motion information is corrected to obtain the corrected patient motion information.

[0115] Therefore, the quality control method for motion information during PET scanning provided in this embodiment, when it is determined that a tomographic fault occurs in the location information to be evaluated, divides the patient's motion information into several segments according to each first sampling time point at the fault location, performs registration on each segment, and corrects the patient information based on the registration information. This makes the corrected motion information more consistent with the patient's actual motion information, laying a solid foundation for reconstructing high-quality PET images.

[0116] In another exemplary embodiment, step B, which involves correcting the list pattern data based on the location information to be evaluated within a preset sampling time period, specifically includes: based on a second preset index, if it is determined that there are outliers in the distribution of the location information to be evaluated within the preset sampling time period, then the following steps are used to correct the list pattern data:

[0117] B21: Based on the second preset index, obtain the second sampling time point of the evaluation location information of each outlier;

[0118] B22: Remove all the list pattern data collected at the second sampling time point to obtain the corrected list pattern data.

[0119] Therefore, the quality control method for motion information during PET scanning provided in this embodiment corrects the list pattern data by deleting the list pattern data corresponding to the second sampling time point of outlier evaluation location information. This eliminates the list pattern data collected under interference conditions, making the corrected list pattern data more reliable and laying a solid foundation for reconstructing high-quality PET images.

[0120] It should be noted that those skilled in the art should understand that the present invention does not limit the specific values ​​of the first preset indicator and the second preset indicator. Taking the first preset indicator as an example, by performing mathematical statistics on the location information to be evaluated according to the sampling time sequence, it can be determined whether the location information to be evaluated has a segmented distribution within the preset sampling time period based on the specific value of the first preset indicator. Similarly, for the second preset indicator, by performing mathematical statistics on the location information to be evaluated according to the sampling time sequence, it can be determined whether the location information to be evaluated has outliers within the preset sampling time period based on the specific value of the second preset indicator. Furthermore, those skilled in the art should understand that in practical applications, when the location information to be evaluated does not meet the preset quality requirements, the present invention does not limit the order of the above two correction methods, and the above two correction methods are not mutually exclusive. For example, for list-mode data after correction (removing outliers), it is still possible that the distribution of the location information to be evaluated within the preset sampling time period may still have gaps. In this case, the patient's motion information can still be corrected (segmented correction based on registration information).

[0121] In summary, the quality control method for motion information during PET scanning provided in this embodiment corrects patient motion information and / or list pattern data that do not meet preset quality requirements in order to reconstruct PET images of the region of interest. While realizing intelligent reconstruction of PET images, it ensures the quality of the reconstructed PET images, realizes an end-to-end process, and thus saves manpower and material costs.

[0122] Example 3

[0123] This embodiment provides a PET data processing device. For details, please refer to [link to relevant documentation]. Figure 4 The diagram illustrates the structure of the PET data processing device provided in this embodiment. Figure 4 As can be seen, the PET data processing device provided in this example includes: a data acquisition unit 110 and a location information acquisition unit 120 to be evaluated, and at least one of an evaluation result acquisition unit 130 and a correction unit 140.

[0124] Specifically, the data acquisition unit 110 is configured to acquire list-mode data and patient motion information at a preset sampling frequency during PET scanning. The evaluation location information acquisition unit 120 is configured to relocate the response lines in the list-mode data using the patient motion information at each sampling time, and generate evaluation location information of the region of interest at that sampling time based on the relocated response lines. The evaluation result acquisition unit 130 is configured to generate a quality evaluation result of the motion information during the PET scan based on preset quality evaluation indicators and the evaluation location information within a preset sampling time period. The correction unit 140 is configured to determine whether the quality evaluation result meets preset quality requirements; if not, it corrects the patient motion information and / or the list-mode data based on the distribution of the evaluation location information within the preset sampling time period.

[0125] Since the PET data processing device provided in this embodiment belongs to the same inventive concept as the quality evaluation method for motion information during PET scanning provided in Embodiment 1 and / or the quality control method for motion information during PET scanning provided in Embodiment 2, the PET data processing device provided in this embodiment has at least all the advantages of the quality evaluation method described in Embodiment 1 and / or the quality control method for motion information during PET scanning provided in Embodiment 2. Here, they will not be described in detail. For details, please refer to Embodiment 1 and / or Embodiment 2 above.

[0126] Example 4

[0127] This embodiment provides a PET imaging system; please refer to [reference needed]. Figure 5 The diagram illustrates the block structure of the PET imaging system provided in this embodiment. Figure 5 As shown, the PET imaging system includes a processor 210 and a memory 230. The memory 230 stores a computer program. When the computer program is executed by the processor 210, it implements the quality evaluation method for motion information during PET scanning as described in any of the above claims to evaluate the patient's motion information and / or the quality control method for motion information during PET scanning as described in any of the above claims to correct the patient's motion information and / or list pattern data.

[0128] like Figure 5As shown, the PET imaging system may further include an imaging device 250, a terminal 260, a network 270, a communication interface 220, and a communication bus 240. The components of the PET imaging system can be connected in one or more ways. For example, in one example, the imaging device 250 can be directly connected to the processor 210 via the communication bus 240 or via the network 270. As another example, the terminal 260 can be directly connected to the processor 210 via the communication bus 240 or via the network 270. The processor 210, the communication interface 220, and the memory 230 communicate with each other via the communication bus 240.

[0129] In some embodiments, the imaging device 250 can scan a patient and acquire patient-related data. In some embodiments, the imaging device 250 can be an emission computed tomography (ECT) device, a positron emission tomography (PET) device, a single-photon emission computed tomography (SPECT) device, a multimodal device, or any combination thereof. Exemplary multimodal devices may include CT-PET imaging systems, MR-PET imaging systems, etc. In some embodiments, the multimodal imaging device 250 may include modules and / or components for performing PET imaging and / or related analyses. In other embodiments, the imaging device 250 may be a PET imaging system.

[0130] Terminal 260 can connect to and / or communicate with imaging device 250, processor 210, and / or memory 230. In some embodiments, terminal 260 includes, but is not limited to, mobile devices, tablet computers, laptop computers, and any combination thereof. In some embodiments, terminal 260 may also include input devices, output devices, etc. Input devices include keyboards, touchscreens (e.g., devices with haptic or haptic feedback), voice input, eye-tracking input, brain monitoring systems, or any other similar input mechanism capable of receiving character and / or numeric input. Other types of input devices may include cursor control devices, such as mice, trackballs, or cursor arrow keys. Output devices may include displays, printers, and any combination thereof.

[0131] The network 270 may include any suitable network 270 that can facilitate the exchange of information and / or data between the PET imaging system and the imaging system. The network 270 may include, but is not limited to, wired or wireless connections, such as Bluetooth, infrared, NFC, local area network, wide area network, etc., which are represented by only one thick dashed line in the figure.

[0132] The communication bus 240 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus 240 can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is used to represent it in the figure, but this does not indicate that there is only one bus or one type of bus. The communication interface 220 is used for communication between the aforementioned PET data processing device and other devices.

[0133] The processor 210 can process data and / or information acquired from the imaging device 250, memory 230, and / or terminal 260. Furthermore, the processor 210 can also serve as the control center of the PET imaging system, connecting various parts of the entire PET imaging system via various interfaces and lines.

[0134] Furthermore, the processor 210 referred to in this invention can be a Central Processing Unit (CPU), or other general-purpose processors 210, digital signal processors 210 (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor 210 can be a microprocessor 210, or any conventional processor 210, etc.

[0135] Additionally, the memory 230 can also be used to store data and / or any other information. In some embodiments, the memory 230 may store data acquired from the imaging device 250, the processor 210, and / or the terminal 260. The data may include image data acquired by the processor 210, algorithms and / or models for processing the image data, etc.

[0136] The memory 230 may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0137] Additionally, code for a computer program that performs the operations of the present invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as the "C" language or similar programming languages.

[0138] In summary, compared with the prior art, the method for quality evaluation and control of motion information during PET scanning, the PET data processing device, and the PET imaging system provided by the present invention have the following advantages:

[0139] The method for evaluating the quality of motion information during PET scanning provided by this invention collects list-pattern data and patient motion information at a preset sampling frequency (e.g., 1 second) within a preset sampling time period (preferably the entire PET scan period, such as 40 minutes). This allows for continuous (the entire preset sampling time period) and finer-grained (same as the sampling frequency) evaluation of the quality of patient motion information. The method generates the location information to be evaluated (including but not limited to the centroid coordinates and rotation scale of the region of interest) by simplified back-projection of all response lines within the preset sampling time period, resulting in high generation efficiency. Furthermore, the quality evaluation results are obtained based on preset quality evaluation indicators and all the location information to be evaluated within the preset sampling time period. This not only ensures high reliability but also eliminates the need for manual intervention, guaranteeing the objectivity and consistency of the quality evaluation results. It significantly saves manpower and material costs and has high quality evaluation efficiency.

[0140] Furthermore, the quality control method for motion information during PET scanning provided by this invention first employs the aforementioned quality evaluation method to obtain a quality evaluation result for the patient's motion information; then, when the quality evaluation result does not meet preset quality requirements, the patient's motion information and / or list pattern data are corrected based on the distribution of the location information to be evaluated within a preset sampling time period. Thus, the quality control method for motion information during PET scanning provided by this invention corrects patient motion information / list pattern data that does not meet preset quality requirements to reconstruct PET images of the region of interest. While achieving intelligent reconstruction of PET images, it ensures the quality of the reconstructed PET images, realizing an end-to-end process and thereby saving manpower and material costs.

[0141] Since the PET data processing device and PET imaging system provided by this invention belong to the same inventive concept as the quality evaluation method and / or quality control method for motion information during PET scanning provided by this invention, they have at least the same beneficial effects, and will not be described in detail here.

[0142] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0143] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0144] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure are within the protection scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for evaluating the quality of motion information during PET scanning, characterized in that, include: During a PET scan, list pattern data of the region of interest and patient motion information are collected according to a preset sampling frequency. At each sampling time, the response line in the list pattern data is relocated using the patient motion information, and the location information to be evaluated of the region of interest at that sampling time is generated based on the relocated response line. Based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period, a quality evaluation result of the patient's motion information is generated.

2. The quality evaluation method according to claim 1, characterized in that, The location information to be evaluated includes the centroid coordinates and / or rotation scale of the region of interest; Before obtaining the centroid coordinates and / or rotation scale of the region of interest, the process also includes: Each response line after relocation at the sampling time is back-projected into the region of interest; Sensitivity correction is performed on each back-projection point after back-projection. Based on the sensitivity-corrected back-projection points, the centroid coordinates and / or rotation scale of the region of interest at that sampling time are obtained.

3. The quality evaluation method according to claim 2, characterized in that, The centroid coordinates of the region of interest at this sampling time are obtained through the following steps: Based on all the back-projection points after the sensitivity correction, a point cloud map of the back-projection points at the sampling time is generated; Based on the point cloud map, the centroid coordinates of the region of interest are calculated.

4. The quality evaluation method according to claim 2, characterized in that, The rotation scale of the region of interest at this sampling time is obtained through the following steps: For each of the back-projection points after sensitivity correction, the second-order rotational inertia matrix is ​​calculated based on the three-dimensional position coordinates of the back-projection point at the sampling time and the sensitivity correction value corresponding to the back-projection point. The rotation matrix is ​​calculated based on the second-order moment of inertia matrix. The rotation matrix is ​​converted into Euler angles in the X, Y, and Z directions to obtain the rotation scale of the region of interest.

5. The quality evaluation method according to claim 2, characterized in that, The step of generating a quality evaluation result for the patient's motion information based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period includes: The distribution stability of the location information to be evaluated is statistically analyzed according to the chronological order of the sampling times. The quality evaluation result of the patient's motion information is given based on the deviation between the distribution stability of the location information to be evaluated and the preset evaluation threshold.

6. A method for quality control of motion information during PET scanning, characterized in that, include: The quality assessment method according to any one of claims 1-5 is used to obtain the quality assessment result of the patient's motion information; Determine whether the quality evaluation result meets the preset quality requirements: if not, then correct the patient movement information and / or list pattern data according to the distribution of the location information to be evaluated within the preset sampling time period.

7. The quality control method according to claim 6, characterized in that, The step of correcting the patient's motion information based on the distribution of the location information to be evaluated within a preset sampling time period includes: According to the first preset index, if it is determined that the distribution of the location information to be evaluated has a discontinuity within the preset sampling time period, the following steps are used to correct the patient's motion information: Acquire each first sampling time point at the location where the location information to be evaluated occurs within the preset sampling time period; and divide the patient's motion information into several segments based on the first sampling time points; For each segment of the patient motion information corresponding to the collected list pattern data, PET image reconstruction without attenuation correction is performed to obtain a reference PET image; Each frame of the reference PET image except the first frame is registered to the first frame of the reference PET image to obtain the registration information corresponding to each frame of the reference PET image except the first frame; Based on the registration information, the patient motion information is corrected to obtain the corrected patient motion information.

8. The quality control method according to claim 6, characterized in that, The step of correcting the list pattern data based on the distribution of the location information to be evaluated within a preset sampling time period includes: According to the second preset index, if it is determined that there are outliers in the distribution of the location information to be evaluated within the preset sampling time period, the following steps are used to correct the list pattern data: According to the second preset index, obtain the second sampling time point of the evaluation location information of each outlier; Remove all the list pattern data collected at the second sampling time point to obtain the corrected list pattern data.

9. A PET data processing device, characterized in that, include: The system includes at least one of a data acquisition unit and a location information acquisition unit, and an evaluation result acquisition unit and a correction unit; wherein, The data acquisition unit is configured to acquire list-pattern data of the region of interest and patient motion information at a preset sampling frequency during PET scanning. The unit for acquiring location information to be evaluated is configured to, at each sampling time, use the patient motion information to relocate the response line in the list pattern data, and generate the location information to be evaluated of the region of interest at that sampling time based on the relocated response line. The evaluation result acquisition unit is configured to generate a quality evaluation result of the patient's motion information based on preset quality evaluation indicators and the location information to be evaluated within a preset sampling time period. The correction unit is configured to determine whether the quality evaluation result meets the preset quality requirements; if not, it corrects the patient movement information and / or the list pattern data according to the distribution of the location information to be evaluated within the preset sampling time period.

10. A PET imaging system, characterized in that, The device includes a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, implements a method for evaluating the quality of motion information during PET scanning as described in any one of claims 1 to 5, and / or a method for controlling the quality of motion information during PET scanning as described in any one of claims 6 to 8, to correct the patient's motion information and / or list pattern data.

Images