CT device and its optical path abnormality detection method

Abstract

The present invention relates to a method for detecting abnormal optical path of a CT device. The CT device includes a radiation source for generating radiation and a detector for detecting radiation. The method includes the following steps: performing a detection scan along the optical path of the CT device to obtain detection scan data, where the optical path is the path that the radiation passes from the radiation source to the detector during scanning; establishing a state characteristic index of the optical path according to the detection scan data; and analyzing the state characteristic index to determine whether the optical path is abnormal. By making the CT device perform a detection scan and analyzing the obtained detection scan data, the present invention can determine whether the optical path components are in a normal state. Compared with the prior art, the present invention does not require manual inspection or the aid of auxiliary equipment, which is more convenient.

Description

[0001] This is a divisional application. The application number of the original application is 201511024391.1, the filing date is December 30, 2015, and the title is CT Equipment and Its Optical Path Abnormality Detection Method. Technical Field

[0002] The present invention relates to CT equipment, and particularly to a CT equipment and its optical path abnormality detection method. Background Art

[0003] Computed Tomography (CT) uses X-ray beams, γ rays, ultrasonic waves, etc. to scan a certain thickness of a layer of a human body part. The detector receives the X-ray beam, γ ray, and ultrasonic wave passing through this layer, converts them into visible light, then converts them into electrical signals through photoelectric conversion, and then converts them into digital signals through an Analog / Digital Converter (ADC) and inputs them into a computer for processing.

[0004] The optical path part in CT equipment includes filters, collimators, detectors, etc. The normal operation of these optical path components has an important impact on the quality of CT images. Before the CT equipment starts to work, it is often necessary to check whether these optical path components are normal, such as whether there are defects or foreign objects, whether they are tilted or shaken, to ensure that these optical path components are in a desired good state. However, some inspections require additional work from the operator. For example, checking for defects or foreign objects in the filter and detector requires the operator to pay a considerable amount of attention. In addition, some inspections, such as checking for the shaking of the filter and the tilt of the collimator, also require auxiliary equipment.

[0005] Therefore, it is desirable to provide a method and device for detecting optical path components of a CT equipment that do not require deep intervention from the operator. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a CT equipment and its optical path abnormality detection method, which can implement detection through the automatic operation of the CT equipment.

[0007] The technical solution adopted by the present invention to solve the above technical problem is to provide an optical path abnormality detection method for a CT equipment. The CT equipment includes a radiation source for generating radiation, a detector for detecting radiation, and an optical path component located between the radiation source and the detector. The method includes the following steps:

[0008] Performing a detection scan along the optical path of the CT equipment to obtain detection scan data, where the optical path is the path that the radiation passes through from the radiation source to the detector during scanning;

[0009] Establish the state characteristic indicators of the optical path component according to the data detected by the detection scan; and

[0010] Analyze the state characteristic indicators to determine whether the state of the optical path component is abnormal;

[0011] When the optical path component is a collimator, the state of the collimator includes whether the slice is tilted, and the state characteristic indicator is the attenuation coefficient of the collimator.

[0012] Optionally, analyzing the state characteristic indicators includes: comparing the state characteristic indicators with a standard characteristic indicator, and determining whether the state of the optical path component is abnormal according to the deviation degree of the comparison; when the optical path component is the collimator, the standard characteristic indicator is the standard attenuation coefficient; and / or, the step of analyzing the state characteristic indicators to determine whether the state of the optical path component is abnormal further includes: determining whether the radiation source and the detector are abnormal, or determining whether the path between the radiation source, the detector and the optical path component located between the radiation source and the detector is abnormal; and / or, the determination of whether the radiation source, the detector and the optical path component located between the radiation source and the detector are abnormal includes whether there is foreign matter.

[0013] Optionally, the detection scan is a stationary detection scan or a rotational detection scan; and / or, the detection scan is a single-focus or multi-focus detection scan; and / or, the number of times of the detection scan is multiple, and the scan conditions for each of the multiple detection scans are the same or different, and the scan conditions include at least one of the following: focus position, energy, object; rotational speed of the rotational scan; radiation source position.

[0014] Optionally, when the number of times of the detection scan is multiple, establish the state characteristic indicators according to the difference value of the data of the multiple scans; and / or, the object is air or a phantom.

[0015] Optionally, the optical path component is a filter, and the state of the filter further includes whether there are defects and whether there is foreign matter. The method includes:

[0016] Make the CT device perform one or more detection scans along the optical path of the CT device under the condition that the filter is included in the optical path, and obtain the first detection scan data;

[0017] Establish the state characteristic surface of the filter according to the first detection scan data; and

[0018] Compare the state characteristic surface with a standard characteristic surface to determine whether the filter has defects and whether there is foreign matter.

[0019] Optionally, it further includes causing the CT device to perform one or more detection scans under the condition that the filter is not included in the optical path, obtaining second detection scan data, and establishing a state characteristic surface of the filter according to a difference value between the first detection scan data and the second detection scan data.

[0020] Optionally, whether the detector is abnormal includes whether there are defects and whether there are foreign objects, and the method includes:

[0021] Causing the CT device to perform one or more detection scans along the optical path of the CT device under the condition that the detector is included in the optical path;

[0022] Establishing a state characteristic surface of the detector according to the data of the detection scan; and

[0023] Comparing the state characteristic surface with a standard characteristic surface to determine whether there are defects and whether there are foreign objects in the detector.

[0024] Optionally, the number of detection scans is multiple, the multiple detection scans are obtained under different scan conditions, and the state characteristic surface is established according to a difference value of the data of the multiple detection scans.

[0025] Optionally, the method for establishing the attenuation coefficient of the collimator includes:

[0026] Causing the CT device to perform one or more detection scans along the optical path of the CT device under the condition that the collimator is included in the optical path and exactly does not block the edge of the detector, obtaining first detection scan data;

[0027] Establishing the attenuation coefficient of the collimator according to the data of the detection scan.

[0028] Optionally, it further includes causing the CT device to perform one or more rotational detection scans under the condition that the collimator is not included in the optical path and completely does not block the edge of the detector, obtaining second detection scan data, and establishing the attenuation coefficient of the collimator according to a difference value between the first detection scan data and the second detection scan data.

[0029] Since the present invention adopts the above technical solutions, by causing the CT device to perform detection scans and analyzing the obtained detection scan data, it can be determined whether the optical path components are in a normal state. Compared with the prior art, the present invention does not require manual inspection or the aid of auxiliary equipment, which is more convenient. Description of the Drawings

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the accompanying drawings, wherein:

[0031] Figure 1 It is a schematic diagram of the overall structure of a computed tomography (CT) device.

[0032] Figure 2 It is a schematic diagram of the internal structure of the cavity of a computed tomography (CT) device.

[0033] Figure 3 It is a flowchart of a method for detecting an optical path anomaly of a CT device according to an embodiment of the present invention.

[0034] Figure 4 It is an example of detecting filter defects and foreign objects in a CT device of the present invention.

[0035] Figure 5 It is experimental data of an example of detecting filter defects and foreign objects in a CT device of the present invention.

[0036] Figure 6 It is an example of detecting filter shaking in a CT device of the present invention.

[0037] Figure 7 It is experimental data of an example of detecting filter shaking in a CT device of the present invention.

[0038] Figure 8 It is an example of detecting detector defects and foreign objects in a CT device of the present invention.

[0039] Figure 9 It is an example of detecting collimator tilt in a CT device of the present invention.

[0040] Figure 10 It is a circuit block diagram of a computed tomography (CT) device. Detailed implementation manners

[0041] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways different from those described herein, and thus the present invention is not limited by the specific embodiments disclosed below.

[0042] Embodiments of the present invention describe a method and apparatus for detecting optical path components of a computed tomography (CT) device, and detect abnormal states on the optical path components of the CT device by operating the CT device, such as defects, foreign objects, shaking or tilting.

[0043] Figure 1 It is a schematic diagram of the structure of a CT device, as Figure 1As shown in the figure, the CT device 100 includes a gantry 110, an examination table 120, a radiation source 131 for generating radiation, and a detector 132 for detecting radiation. For example, the gantry 110 has a rotatable part 130 that rotates around the axis S of the device. The rotatable part 130 has a radiation system, which consists of a relatively arranged radiation source 131 and a detector 132. The radiation used by the radiation source 131 is X-ray. There is a scanning cavity 135 in the center of the rotatable part 130, and the examination table 120 can be moved into and out of the scanning cavity 135.

[0044] During the examination, the subject on the examination table 120 can be pushed into the scanning cavity 135 along the Z axis. The radiation source 131 rotates around the S axis, and the detector 132 moves together with the radiation source 131 to collect projection measurement data, which are then used for image reconstruction. Helical scanning can also be performed. During helical scanning, by the continuous movement of the subject along the S axis and the simultaneous rotation of the radiation source 131, the radiation source 131 generates a helical trajectory relative to the subject.

[0045] The CT device 100 may further include a controller 140 and a processor 142. The controller 140 is used to control the components of the CT device 100 according to a specific scanning protocol during the scanning process. The processor 142 is used to reconstruct an image based on the raw data collected by the detector 132. Figure 2 It is a schematic diagram of the internal structure of the cavity of a computed tomography (CT) device. As Figure 2 shown in the figure, a radiation source 131, a detector 132, a filter 133, and a collimator 134 are arranged on the rotatable part 130 of the CT device 100. The radiation source 131 and the detector 132 are respectively arranged at opposite ends of the rotatable part 130. The filter 133 and the collimator 134 are sequentially arranged on the rotatable part 130 and are located between the radiation source 131 and the subject 200. During operation, the radiation source 131 emits radiation R for detecting the subject 200. The detector 132 is used to receive the radiation R that has passed through the subject 200 and convert the detected radiation R into data required for subsequent image reconstruction.

[0046] The collimator 134 is used to control the irradiation range of the radiation R, and thus control the slice thickness of the part of the subject 200 to be scanned. The collimator 134 includes a plurality of slices whose positions can be controlled. The filter 133 is located between the radiation source 131 and the collimator 134, and is used to absorb low-energy radiation R and can control the irradiation intensity distribution of the radiation R.

[0047] When the CT device is working, the X-rays emitted from the ray source 131 will pass through components such as the filter 133 and the collimator 134, and finally reach the detector 132. The path that the rays pass through from the ray source 131 to the detector 132 during this scan is called the optical path. If there is an abnormality in this optical path, for example, the detector 132 or the filter 133 is defective or there is foreign matter on it, the filter 133 shakes or the collimator 134 is tilted, or there is foreign matter in the area between these components, it will affect the performance of the device. Advantageously, the abnormality of the optical path, such as the abnormal state of the detector 132, the filter 133, and the collimator 134 or the area between them, will be reflected in the data received by the detector 132 during the scan. Therefore, by analyzing these data, it is possible to determine whether there is an abnormal state in the detector 132, the filter 133, the collimator 134, or the area between them. For example, state characteristic indicators are established for the state of whether the detector 132 and the filter 133 are defective or have foreign matter, and are characterized by a characteristic surface; or state characteristic indicators are established for the state of whether the filter 133 shakes, which is characterized by a center-of-gravity parameter; or state characteristic indicators are established for the state of whether the collimator 134 is tilted, which is characterized by an attenuation coefficient; or state characteristic indicators are established for the area between the filter 133, the collimator 134, and the detector 132. By analyzing the state characteristic indicators of the detector 132, the filter 133, the collimator 134, and the area between them, it is possible to determine whether there is an abnormality in these components.

[0048] Of course, the embodiments of the present invention are not limited to judging these components, and may also be other components in the optical path of the CT device, as long as their states can be reflected in the scan data. Accordingly, state characteristic indicators can be established according to the characteristics of the optical path components.

[0049] Figure 3 It is a flowchart of a method for detecting an abnormality in the optical path of a CT device according to an embodiment of the present invention.

[0050] Reference Figure 3 As shown, the method includes the following steps:

[0051] Step 301, perform a detection scan along the optical path of the CT device to obtain detection scan data.

[0052] During the scan, the optical path components need to be included in the optical path, which means that the optical path components will affect the scan data. Taking Figure 2 the filter 133 as an example, including the filter 133 in the optical path means that the rays will pass through the filter 133 to reach the subject 200, so the signal sensed on the detector 132 will reflect the influence of the filter 133, and this influence will be transmitted to the scan data converted from the sensed signal. Taking Figure 2For the detector 132, since it is a component required for sensing signals, the detector 132 is included in the optical path. For Figure 2 the collimator 134, as long as the ray is blocked by at least one slice of the collimator 134, the collimator 134 is included in the optical path.

[0053] Here, the number of scans can be one or more. For the case of multiple scans, the scan conditions can be the same or different. The scan conditions are, for example, the focal position, energy, object; the rotation speed of rotational scanning; the ray source position, etc. In one aspect, the number can be determined according to the reliability requirement. For example, comprehensively considering the results of multiple scans under the same scan conditions helps to improve the reliability of the scan data and reduce accidental interference. On the other hand, the number can be determined according to the accuracy requirement. For example, comprehensively considering the results of multiple scans under different scan conditions helps to improve the accuracy or sensitivity of the scan data. For example, in the conventional case, scanning is only required at a single focal position, and comparing the scan data obtained at different focal positions can improve the accuracy or sensitivity of the scan data. To obtain data at different focal positions, multi-focal scanning can be performed, and flying focal scanning can also be introduced. The energy is the energy of the ray radiated by the ray source 131. The object can be air (i.e., without placing a phantom on Figure 1 the examination bed) or a phantom. During multiple scans, a state characteristic index can be established based on the difference value of the data from multiple scans to improve the detection sensitivity.

[0054] Here, the scan mode can be static scanning or rotational scanning, which can be determined according to the characteristics of the state detection of the optical path components. For example, for foreign object, defect, or tilt detection, both static scanning and rotational scanning are applicable. In step 302, a state characteristic index of the optical path is established based on the detection scan data.

[0055] The state characteristic index characterizes a certain aspect of the optical path component, such as the state of defect, foreign object, wobbling, or tilt. For example, the characteristic surface established for the detector 132 and the filter 133 characterizes whether there are defects or foreign objects in these components; or the center-of-gravity parameter established for the filter 133 characterizes whether this component wobbles; or the attenuation coefficient characteristic established for the collimator 134 characterizes whether this component is tilted.

[0056] In step 303, the state characteristic index is analyzed to determine whether the optical path is abnormal.

[0057] Since the state characteristic index can characterize the state of the associated optical path component, by analyzing this index, the state of the optical path component in the relevant aspect can be determined. For example, the state of the optical path component includes whether there is a defect, whether there is a foreign object, whether it wobbles, and whether it is tilted.

[0058] Optionally, according to an embodiment of the present invention, standard state characteristic indexes are pre-established for the normal states of the detector 132, the filter 133, and the collimator 134. For example, standard state characteristic indexes are established for the state where the detector 132 and the filter 133 are free of defects and foreign objects, which is characterized by a standard characteristic surface; or standard state characteristic indexes are established for the state where the filter 133 has no shaking, which is characterized by a relatively stable center-of-gravity parameter; or standard state characteristic indexes are established for the state where the collimator 134 has no tilt, which is characterized by a reasonable attenuation coefficient. By comparing the state characteristic indexes of the detector 132, the filter 133, and the collimator 134 with the standard state characteristic indexes and calculating their deviation degrees, it can be determined whether there are abnormalities in these components.

[0059] Since the state characteristic index can also characterize the state of the region between the optical path components associated therewith, the state of the optical path in relevant aspects can be determined by analyzing this index. For example, whether there are foreign objects in the region between the optical path components.

[0060] Figure 4 is an example of detecting defects and foreign objects in the filter of the CT device of the present invention. Refer to Figure 4 As shown, in this example, the detection method is specifically embodied in the following steps:

[0061] In step 401, one or more detection scans are performed along the optical path of the CT device to obtain first detection scan data.

[0062] Specifically, a detection scan with air as the object and with the filter can be performed first, and then a detection scan with air as the object and without the filter can be performed. The scan data of the two detection scans are used as the first detection scan data.

[0063] In step 402, a state characteristic surface of the filter is established according to the first detection scan data.

[0064] Specifically, the scan data of the two detection scans obtained in step 401 can be divided to obtain the state characteristic surface L1 of the filter. In step 403, the state characteristic surface is compared with a standard characteristic surface to determine whether the filter has defects and whether there are foreign objects.

[0065] Specifically, the state characteristic surface L1 can be smoothed to obtain L1_smooth, and L1_smooth is used as the standard characteristic surface. By determining whether L1_smooth - L1 exceeds a certain threshold, it can be determined whether the filter has defects or foreign objects.

[0066] In step 401, the detection scan method can be static detection scan or rotational detection scan. To eliminate errors, different detection scan data can be obtained by performing detection scans multiple times under different conditions, and these detection scan data can be comprehensively considered. For example, in step 401, the CT device can also perform one or more detection scans under the condition that the filter is not included in the optical path to obtain second detection scan data. Then in step 402, a state feature surface can be established based on the difference value between the first detection scan data and the second detection scan data. Those skilled in the art can also select other scan conditions accordingly to obtain different detection scan data. Here, the calculation of the difference value can be subtracting the two detection scan data or dividing the two detection scan data.

[0067] In step 403, when comparing the state feature surface with the standard feature surface, each point on the state feature surface is compared with each point on the standard feature surface to determine whether the difference of any point exceeds a threshold. If it exceeds, it is considered whether there is a defect or foreign object in the filter.

[0068] In step 403, the standard feature surface can also be obtained and saved in advance. For example, steps 401 and 402 are pre-executed under the condition that the filter is free of defects and foreign objects, and the obtained feature surface is used as the standard feature surface.

[0069] Figure 5 is the state feature surface obtained from the example of detecting defects and foreign objects in the filter of the CT device. Figure 5 (a) The abscissa represents each channel of the detector, and the ordinate represents the data obtained by dividing the scan data of the two detection scans. 51 is the state feature surface L1 obtained by the detection scan, and 52 is the standard feature surface L1_smooth. Figure 5 (b) The ordinate represents the value of L1_smooth - L1. As Figure 5 shown, the state feature surface L1 has an image in the middle compared with the standard feature surface L1_smooth. If the mutation value (i.e., L1_smooth - L1) exceeds a certain threshold, it is determined whether there is a defect or foreign object in the filter.

[0070] Figure 6 is an example of detecting filter shake in the CT device of the present invention. In this example, the detection method is specifically implemented as the following steps:

[0071] In step 601, one or more detection scans are performed along the optical path of the CT device to obtain first detection scan data.

[0072] In step 602, a state feature surface of the filter is established based on the first detection scan data.

[0073] In this embodiment, the further details of steps 601 and 602 are the same as those of steps 401 and 402 in the previous embodiment, and will not be elaborated here. It should be noted that the detection scan performed in this embodiment must be a scan of the rotating gantry. In step 603, the centroid parameter of the filter is obtained according to the state characteristic surface.

[0074] Specifically, the centroid parameter is obtained by calculating the geometric centers of the filter in the Channel and Slice directions at each view angle of the rotating detection scan.

[0075] In step 604, the centroid parameter is analyzed to determine whether the filter is shaking.

[0076] Figure 7 is the centroid parameter of the filter obtained in the example of detecting the shaking of the filter of the CT device. Refer to Figure 7 , where the abscissa represents the different view directions, and the ordinate represents the centroid position. When the filter is not shaking, the centroid positions in these different view directions should be fixed, that is, it should be a straight line parallel to the horizontal axis; if the filter shakes, the centroids of the filter in each view direction do not coincide, presenting a curve as shown in Figure 7 . Therefore, if the maximum deviation value or the average deviation value of the centroid of the filter in each view direction exceeds a certain threshold, it is determined that the filter is shaking; if the deviation value of the centroid of the filter in each view direction does not exceed the threshold, it is determined that the filter is not shaking.

[0077] Figure 8 is an example of detecting detector defects and foreign objects in the CT device of the present invention. Refer to Figure 8 shown. In this example, the detection method is specifically implemented as the following steps:

[0078] In step 801, the CT device performs one or more detection scans along the optical path of the CT device under the condition that the detector is included in the optical path.

[0079] In step 802, a state characteristic surface of the detector is established according to the data of the detection scan.

[0080] In step 803, the state characteristic surface is compared with a standard characteristic surface to determine whether the detector has defects and whether there are foreign objects.

[0081] In step 801, the detection scan mode can be a stationary detection scan or a rotating detection scan. In the rotating detection scan mode, the detection scan data in each view direction are averaged.

[0082] To improve the accuracy, different detection scan data can be obtained by performing multiple detections and scans under different conditions, and these detection scan data can be comprehensively considered. For example, in step 801, two detection scans can be performed at two focal points to obtain detector data at the two focal point positions, and then a state characteristic surface can be established based on the difference value between the two detection scan data. Or perform a scan under a flying focal point to obtain data at two focal point positions, and then establish a state characteristic surface based on the difference value between the two detection scan data. Another example is to detect and scan air once and then detect and scan a phantom once to obtain two detection scan data, and then establish a state characteristic surface based on the difference value between the two detection scan data. Here, the phantom is preferably a thick and uniform phantom to increase the ray hardness. Another example is to perform two detection scans at different energies to obtain two detection scan data, and then establish a state characteristic surface based on the difference value between the two detection scan data. Of course, those skilled in the art can also select other scan conditions accordingly to obtain different detection scan data. Here, the calculation of the difference value can be to subtract the two detection scan data or divide the two detection scan data.

[0083] In step 803, when comparing the state characteristic surface with the standard characteristic surface, each point on the state characteristic surface is compared with each point on the standard characteristic surface to determine whether the difference value of any point exceeds a threshold. If it exceeds, it is considered whether there is a defect or foreign object in the detector.

[0084] In step 803, the standard characteristic surface can be obtained and saved in advance. For example, steps 801 and 802 are pre-executed under the condition that the detector is free of defects and foreign objects, and the obtained characteristic surface is used as the standard characteristic surface. As an alternative, the standard characteristic surface can be obtained immediately after step 802 by performing a smoothing operation on the state characteristic surface.

[0085] Figure 9 is an example of collimator tilt detection of the CT device of the present invention. Refer to Figure 9 As shown, in this example, the detection method is specifically embodied as the following steps:

[0086] In step 901, the CT device is made to perform one or more detection scans along the optical path of the CT device under the condition that the collimator is included in the optical path and just does not block the edge of the detector.

[0087] In step 902, the attenuation coefficient of the collimator is established based on the detection scan data.

[0088] In step 903, the attenuation coefficient is compared with a standard attenuation coefficient to determine whether the slice of the collimator is tilted.

[0089] In step 901, the scanning method can be stationary detection scanning or rotational detection scanning. The setting that the collimator just does not block the edge of the detector can make the collimator not block a row of the detector edge.

[0090] To eliminate errors, different detection scanning data can be obtained by performing multiple detection scans under different conditions, and these detection scanning data can be comprehensively considered. For example, in step 901, the CT device can also perform one or more rotational detection scans under the condition that the collimator is not included in the optical path and does not block a row of the detector edge at all, to obtain second detection scanning data. Then in step 902, the attenuation coefficient of the collimator can be established according to the difference value between the first detection scanning data and the second detection scanning data. Those skilled in the art can also select other scanning conditions to obtain different detection scanning data accordingly. Here, the calculation of the difference value can be subtracting the two detection scanning data or dividing the two detection scanning data.

[0091] In step 903, by comparing the attenuation coefficient with the standard attenuation coefficient to determine whether the attenuation coefficient exceeds the threshold value compared with the standard attenuation coefficient, it is determined whether the collimator slice is tilted.

[0092] Figure 10 It is a circuit block diagram of a computed tomography (CT) device. Refer to Figure 10 As shown, the circuit includes the aforementioned radiation source 131 and detector 132, as well as a controller 140, a processor 142, and a display 146. The radiation source 131 is used to generate radiation, and it is arranged on the rotatable part of the CT device. The detector 132 is used to detect radiation, and it is arranged on the rotatable part and is arranged opposite to the radiation source 131. The radiation source 131 and the detector 132 form an image scanner for collecting projection measurement data of the subject. The processor 142 is connected to the detector 132 to obtain the projection measurement data of the subject for subsequent processing. The controller 140 is connected to the radiation source 131 to control the scanning process. The display 146 is used to present the interface, data, and images to the user. The controller 140 is connected to the radiation source 131 to control the scanning process. The controller 140 is also connected to the processor 142 and the display 146 to control the operation of these two components.

[0093] According to this embodiment, the controller 140 is configured to perform detection scanning along the optical path of the CT device. The processor 142 is connected and configured to obtain detection scanning data, establish a state characteristic index of the optical path according to the detected scanning data, and analyze the state characteristic index to determine whether the optical path is abnormal.

[0094] According to the previous embodiments, the controller 140 and the processor 142 can perform specific detection operations according to different anomaly detections. For example, if there are defects or foreign objects in the detector 132 and the filter 133, then perform as Figure 4 、8 the operations shown. If it is detected whether the filter 133 is wobbling, then execute Figure 6 the operations shown. If it is detected whether the collimator 134 is tilted, then execute as Figure 9 the operations shown. The details of these operations and other details of the operation of the CT apparatus have been described in detail in the foregoing embodiments and will not be elaborated herein.

[0095] The method for detecting an optical path component of the CT apparatus according to the foregoing embodiments of the present invention can be implemented in a computer-readable medium such as computer software, hardware, or a combination of computer software and hardware. For hardware implementation, the embodiments described in the present invention can be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic devices for performing the above functions, or a selected combination of the above devices. In some cases, such embodiments can be implemented by a controller.

[0096] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the claims.

Claims

1. A method for detecting abnormal optical path of a CT device, the CT device comprising a radiation source for generating radiation, a detector for detecting radiation, and an optical path component located between the radiation source and the detector, characterized in that, The method includes the following steps: Performing a detection scan along the optical path of the CT device to obtain detection scan data, where the optical path is the path that the ray passes from the ray source to the detector during scanning; Establishing a state characteristic index of the optical path component according to the detection scan data; and Analyzing the state characteristic index to determine whether the state of the optical path component is abnormal; When the optical path component is a collimator, the state of the collimator includes whether the slice is tilted, and the state characteristic index is the attenuation coefficient of the collimator.

2. The method according to claim 1, characterized in that Analyzing the state characteristic index includes: comparing the state characteristic index with a standard characteristic index, and determining whether the state of the optical path component is abnormal according to the deviation degree of the comparison; when the optical path component is the collimator, the standard characteristic index is the standard attenuation coefficient; and / or, the step of analyzing the state characteristic index to determine whether the state of the optical path component is abnormal further includes: determining whether the ray source and the detector are abnormal; and / or, the step of analyzing the state characteristic index to determine whether the state of the optical path component is abnormal further includes: determining whether there is foreign matter in the path between the ray source, the detector, and the optical path components located between the ray source and the detector.

3. The method according to claim 1, characterized in that, Analyzing the state characteristic index includes: comparing the state characteristic index with a standard characteristic index, and determining whether the state of the optical path component is abnormal according to the deviation degree of the comparison; when the optical path component is the collimator, the standard characteristic index is the standard attenuation coefficient; and / or, determining whether the path between the ray source, the detector, and the optical path components located between the ray source and the detector is abnormal.

4. The method according to claim 3, wherein Determining whether the path between the ray source, the detector, and the optical path components located between the ray source and the detector is abnormal includes whether there is foreign matter.

5. The method according to claim 1, characterized in that The detection scan is a stationary detection scan or a rotational detection scan; and / or, the detection scan is a single-focus or multi-focus detection scan; and / or, the number of detection scans is multiple, and the scan conditions for each of the multiple detection scans are the same or different, and the scan conditions include at least one of the following: focal position, energy, object; rotational speed of rotational scan; ray source position.

6. The method according to claim 5, wherein When the number of detection scans is multiple, establishing the state characteristic index according to the difference value of the data of multiple scans; and / or, the object is air or a phantom.

7. The method according to any one of claims 2-4, characterized in that, The optical path component is a filter, and the state of the filter further includes whether there are defects and whether there is foreign matter. The method includes: Making the CT device perform one or more detection scans along the optical path of the CT device under the condition that the filter is included in the optical path to obtain first detection scan data; Establishing a state characteristic surface of the filter according to the first detection scan data; and Comparing the state characteristic surface with a standard characteristic surface to determine whether the filter has defects and whether there is foreign matter.

8. The method according to claim 7, wherein It further includes causing the CT device to perform one or more detection scans under the condition that the filter is not included in the optical path, obtaining second detection scan data, and establishing a state characteristic surface of the filter according to a difference value between the first detection scan data and the second detection scan data.

9. The method according to claim 5, characterized in that, Whether the detector is abnormal includes whether there are defects and whether there is foreign matter, and the method includes: Causing the CT device to perform one or more detection scans along the optical path of the CT device under the condition that the detector is included in the optical path; Establishing a state characteristic surface of the detector according to the data of the detection scan; and Comparing the state characteristic surface with a standard characteristic surface to determine whether there are defects and whether there is foreign matter in the detector.

10. The method according to claim 9, wherein The number of the detection scans is multiple, the multiple detection scans are obtained under different scan conditions, and the state characteristic surface is established according to a difference value between the data of the multiple detection scans.

11. The method according to claim 1, wherein The method for establishing the attenuation coefficient of the collimator includes: Causing the CT device to perform one or more detection scans along the optical path of the CT device under the condition that the collimator is included in the optical path and just does not block the edge of the detector, obtaining first detection scan data; Establishing the attenuation coefficient of the collimator according to the data of the detection scan.

12. The method according to claim 11, wherein It further includes causing the CT device to perform one or more rotational detection scans under the condition that the collimator is not included in the optical path and does not block the edge of the detector at all, obtaining second detection scan data, and establishing the attenuation coefficient of the collimator according to a difference value between the first detection scan data and the second detection scan data.

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