EPID-Based Detection Method, Device, Equipment and Medium for Electron Linear Accelerator

Abstract

The present invention provides an EPID-based detection method, device, equipment and medium for an electron linear accelerator, relating to the field of electron linear accelerator detection; the method includes the following steps: collecting multiple EPID images of an EPID irradiating a target object multiple times, and taking each of the EPID images as a target image; calculating the MU linear value of the electron linear accelerator based on the multiple target images, and calculating the field flatness value and the field symmetry value of the electron linear accelerator based on a single target image; determining whether the MU linear value, the field flatness value and the field symmetry value are respectively within their corresponding set requirement ranges; applying the imaging function of the EPID system to the daily detection of the electron linear accelerator, greatly improving the daily detection efficiency of the electron linear accelerator, eliminating the need to rely on additional purchased quality control equipment, and reducing the cost of daily detection.

Description

Technical Field

[0001] The present invention relates to the field of electron linear accelerator detection, and more specifically, to an electron linear accelerator detection method, device, equipment and medium based on an EPID. Background Art

[0002] Currently, radiotherapy has become one of the main means of tumor treatment. As the main equipment for radiotherapy, the stability of medical electron linear accelerators directly affects the effect of radiotherapy. The daily detection of electron linear accelerators is a very important aspect of quality control. The traditional daily detection of electron linear accelerators includes the detection of main indicators such as MU linearity, field flatness, and field symmetry; traditional detection instruments include ionization chambers, morning inspection instruments, and three-dimensional water tanks. However, these traditional detection devices are complex and time-consuming to operate during the daily accelerator detection process. At the same time, EPID devices have become standard configuration devices for accelerators. Therefore, there is an urgent need to develop a daily detection method and device for electron linear accelerators based on EPIDs. Summary of the Invention

[0003] The purpose of the present invention is to provide an electron linear accelerator detection method, device, equipment and medium based on an EPID to solve the problems existing in the above background art.

[0004] Embodiments of the present invention are implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides an electron linear accelerator detection method based on an EPID, including the following steps:

[0006] Collect multiple EPID images of the EPID irradiating a target object multiple times, and use each EPID image as a target image;

[0007] Based on the multiple target images, calculate the MU linearity value of the electron linear accelerator, and based on a single target image, calculate the field flatness value and field symmetry value of the electron linear accelerator;

[0008] Judge whether the MU linearity value, field flatness value, and field symmetry value are respectively within their corresponding set requirement ranges;

[0009] If the MU linearity value, field flatness value, and field symmetry value are all within their corresponding set requirement ranges, obtain a first result that the MU linearity index, field flatness index, and field symmetry index of the electron linear accelerator are all qualified;

[0010] If the MU linear value is not within the corresponding set requirements range, a second result indicating that the MU linear index of the electron linear accelerator is unqualified is obtained; if the field flatness value is not within the corresponding set requirements range, a third result indicating that the field flatness index of the electron linear accelerator is unqualified is obtained; if the field symmetry value is not within the corresponding set requirements range, a fourth result indicating that the field symmetry index of the electron linear accelerator is unqualified is obtained.

[0011] The beneficial effects of the present invention are as follows: By applying the imaging function of the EPID system to the daily detection of the electron linear accelerator, the daily detection efficiency of the electron linear accelerator is greatly improved, without relying on additional purchased quality control equipment, and the cost of daily detection is reduced.

[0012] On the basis of the above technical solutions, the present invention can be further improved as follows.

[0013] Further, calculating the MU linear value of the electron linear accelerator according to multiple target images includes:

[0014] Calculating multiple target averages according to multiple target images, where the multiple target images include multiple groups of calculation images, and the MU values of the electron linear accelerator corresponding to the multiple groups of calculation images. Among them, the MU values corresponding to adjacent two groups of calculation images have a difference of a preset value between the two MU values, and the multiple target averages are the gray scale averages of the multiple groups of calculation images;

[0015] Calculating the MU linear value through the multiple target averages and the MU values corresponding to the target averages;

[0016] Among them, calculating the multiple target averages through the first formula, and the first formula is expressed as:

[0017]

[0018] In the formula, D ci represents the target average corresponding to the preset MU value, n represents the number of obtaining multiple groups of calculation images, and D cin represents the measured value corresponding to the preset MU value;

[0019] Calculating the values of S and b through the multiple target averages, and expressing the relationship between the gray scale value of the center point of the target image, S and b through the second formula, and the second formula is expressed as:

[0020] D c = SU + b;

[0021] In the formula, D c is the gray scale value of the center point of the target image, S is the linear factor, U is the corresponding MU value, and b is the intercept of the straight line with the vertical coordinate;

[0022] The MU linear value of the electron linear accelerator is calculated through the third formula, and the third formula is expressed as:

[0023]

[0024] In the formula, D c is the gray value of the center point of the target image obtained, D m is the measured gray value corresponding to the MU value, U m is the MU value corresponding to D c .

[0025] The beneficial effect of adopting the above further scheme is that the MU linear value of the electron linear accelerator is obtained by the target average value and the preset MU value corresponding to the electron linear accelerator when each target image is obtained.

[0026] Further, calculating the field flatness value of the electron linear accelerator according to the single target image includes:

[0027] Intercept the single target image according to the preset field width ratio to obtain the target intercepted image corresponding to the single target image;

[0028] Calculate the maximum gray value and the minimum gray value in the target intercepted image according to the target intercepted image;

[0029] Calculate the field flatness value of the electron linear accelerator according to the maximum gray value and the minimum gray value;

[0030] Among them, calculating the field flatness value of the electron linear accelerator according to the maximum gray value and the minimum gray value, the field flatness value is calculated through the fourth formula, and the fourth formula is expressed as:

[0031]

[0032] In the formula, D max represents the maximum gray value, D min represents the minimum gray value.

[0033] The beneficial effect of adopting the above further scheme is that the field flatness value can be obtained by the ratio of the maximum gray value and the minimum gray value, and thus the field flatness value of the electron linear accelerator can be obtained.

[0034] Further, calculating the field symmetry value of the electron linear accelerator according to the single target image includes:

[0035] Construct a plane rectangular coordinate system with the center point coordinates of the single target image;

[0036] According to the plane rectangular coordinate system, at least one set of target gray values is calculated and obtained. The target gray values include a first gray value and a second gray value, and the first gray value and the second gray value are symmetric with each other about the center of the plane rectangular coordinate system;

[0037] According to the first gray value and the second gray value, the field symmetry value of the electron linear accelerator is calculated and obtained;

[0038] Among them, for calculating the field symmetry value of the electron linear accelerator according to the first gray value and the second gray value, the field symmetry value is calculated by a fifth formula, and the fifth formula is expressed as:

[0039]

[0040] In the formula, x i represents the first gray value, x -i represents the second gray value, i is the i-th pixel point from the origin, and -i is the i-th pixel point in the opposite direction.

[0041] The beneficial effect of adopting the above further scheme is: at least one set of target gray values is taken in the established plane rectangular coordinate system. For the first gray value and the second gray value in the target gray values, the first gray value and the second gray value are symmetric with each other about the center of the plane rectangular coordinate system, and the field symmetry value of the electron linear accelerator is obtained through the first gray value and the second gray value.

[0042] Further, the set requirement range corresponding to the above MU linear value is a first set range, the set requirement range corresponding to the field flatness value is a second set range, and the set requirement range corresponding to the field symmetry value is a third set range; judging whether each of the MU linear value, the field flatness value, and the field symmetry value is within its corresponding set requirement range includes:

[0043] Compare the MU linear value with the first set range. If the MU linear value is within the first set range, it is determined that the MU linear value is within the set requirement range corresponding to the MU linear value. If the MU linear value is not within the first set range, it is determined that the MU linear value is not within the set requirement range corresponding to the MU linear value;

[0044] Compare the field flatness value with the second set range. If the field flatness value is within the second set range, it is determined that the field flatness value is within the set requirement range corresponding to the field flatness value. If the field flatness value is not within the second set range, it is determined that the field flatness value is not within the set requirement range corresponding to the field flatness value;

[0045] Compare the field symmetry value with the third set range. If the field symmetry value is within the third set range, it is determined that the field symmetry value is within the set requirement range corresponding to the field symmetry value. If the field symmetry value is not within the third set range, it is determined that the field symmetry value is not within the set requirement range corresponding to the field symmetry value.

[0046] The beneficial effect of adopting the above further solution is: obtaining the results of whether the MU linear index, field flatness index, and field symmetry index of the electron linear accelerator are qualified.

[0047] In a second aspect, an embodiment of the present application provides an electron linear accelerator detection device based on an EPID, including:

[0048] An acquisition module, configured to acquire multiple EPID images of the EPID irradiating a target object multiple times, and use each EPID image as a target image;

[0049] A calculation module, configured to calculate the MU linear value of the electron linear accelerator according to multiple target images, and is further configured to calculate the field flatness value and field symmetry value of the electron linear accelerator according to a single target image;

[0050] A judgment module, configured to judge whether each of the MU linear value, field flatness value, and field symmetry value is within its corresponding set requirement range;

[0051] A qualified module, configured to, if the MU linear value, field flatness value, and field symmetry value are all within their corresponding set requirement ranges, obtain a first result that the MU linear index, field flatness index, and field symmetry index of the electron linear accelerator are all qualified;

[0052] An unqualified module, configured to, if the MU linear value is not within the corresponding set requirement range, obtain a second result that the MU linear index of the electron linear accelerator is unqualified; if the field flatness value is not within the corresponding set requirement range, obtain a third result that the field flatness index of the electron linear accelerator is unqualified; if the field symmetry value is not within the corresponding set requirement range, obtain a fourth result that the field symmetry index of the electron linear accelerator is unqualified.

[0053] Further, the above calculation module includes:

[0054] An average value calculation unit, configured to calculate the target average value of the central gray levels of multiple target images;

[0055] A linear value calculation unit, configured to calculate the MU linear value through the MU value preset for the electron linear accelerator corresponding to each target image and the target average value, where, for the MU values of the electron linear accelerator corresponding to two adjacent target images, the difference between the two MU values is a preset value;

[0056] An interception unit, configured to intercept a single target image according to a preset field width ratio to obtain a target intercepted image corresponding to the single target image;

[0057] A grayscale value calculation unit, configured to calculate a maximum grayscale value and a minimum grayscale value in the target intercepted image according to the target intercepted image;

[0058] A flatness value calculation unit, configured to calculate a field flatness value of an electron linear accelerator according to the maximum grayscale value and the minimum grayscale value;

[0059] A construction unit, configured to construct a plane rectangular coordinate system with the center point coordinates of a single target image;

[0060] A target grayscale value calculation unit, configured to calculate at least one set of target grayscale values according to the plane rectangular coordinate system, where the target grayscale values include a first grayscale value and a second grayscale value, and the first grayscale value and the second grayscale value are symmetric about the center of the plane rectangular coordinate system;

[0061] A symmetry value calculation unit, configured to calculate a field symmetry value of an electron linear accelerator according to the first grayscale value and the second grayscale value.

[0062] Further, the set requirement range corresponding to the above MU linear value is a first set range, the set requirement range corresponding to the field flatness value is a second set range, and the set requirement range corresponding to the field symmetry value is a third set range. The judgment module includes:

[0063] A linear value judgment unit, configured to compare the MU linear value with the first set range. If the MU linear value is within the first set range, it is determined that the MU linear value is within the set requirement range corresponding to the MU linear value; if the MU linear value is not within the first set range, it is determined that the MU linear value is not within the set requirement range corresponding to the MU linear value;

[0064] A flatness value judgment unit, configured to compare the field flatness value with the second set range. If the field flatness value is within the second set range, it is determined that the field flatness value is within the set requirement range corresponding to the field flatness value; if the field flatness value is not within the second set range, it is determined that the field flatness value is not within the set requirement range corresponding to the field flatness value;

[0065] A symmetry value judgment unit, configured to compare the field symmetry value with the third set range. If the field symmetry value is within the third set range, it is determined that the field symmetry value is within the set requirement range corresponding to the field symmetry value; if the field symmetry value is not within the third set range, it is determined that the field symmetry value is not within the set requirement range corresponding to the field symmetry value.

[0066] In a third aspect, an embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method according to any one of the first aspect is implemented.

[0067] In a fourth aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium, characterized in that the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the method according to any one of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0069] Figure 1 It is a flowchart of the method for detecting an electron linear accelerator in an embodiment of the present invention;

[0070] Figure 2 It is a schematic connection diagram of the electron linear accelerator detection device in an embodiment of the present invention;

[0071] Figure 3 It is a schematic connection diagram of the electronic device in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0072] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0073] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0074] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0075] Embodiment

[0076] In a first aspect, the present embodiment provides an EPID-based detection method for an electron linear accelerator, including the following steps:

[0077] S1. Collect multiple EPID images of the EPID irradiating a target object multiple times, and use each EPID image as a target image;

[0078] Among them, the EPID is a real-time image verification system, also known as an electronic portal imaging device (EPID). The EPID system consists of two parts: ray detection and computer processing of ray signals. The differences between different systems are mainly manifested in the former part, and the latter part is the same or similar for all systems. This system verifies the position of radiotherapy before and during the treatment of patients. By matching the irradiation field image with the digitally reconstructed image generated by the simulation positioning film or treatment planning system, the geometric accuracy of the patient's setup irradiation field is verified. In this solution, through the imaging function of the EPID system, the EPID images obtained are used to verify the MU linearity index, beam flatness index, and beam symmetry index of the electron linear accelerator.

[0079] Specifically, before collecting the EPID image, it is necessary to first adjust the position of the EPID board of the EPID system, that is, by moving the EPID board, ensure that the center of the EPID board coincides with the radiation field center of the electron linear accelerator. The radiation field center of the electron linear accelerator refers to the center point of the irradiation field formed on the central plane after the tungsten gate of the electron linear accelerator is opened.

[0080] Among them, since the target object in the target image is in the process of detecting the electron linear accelerator, the target object can be the environment or a human model, that is, the content in the target image is uncertain.

[0081] S2. Calculate the MU linearity value of the electron linear accelerator based on multiple target images, and calculate the beam flatness value and beam symmetry value of the electron linear accelerator based on a single target image;

[0082] Among them, when calculating the MU linearity value of the electron linear accelerator, multiple target images are required; while when calculating the beam flatness value and beam symmetry value of the electron linear accelerator, a single target image can be used.

[0083] Optionally, the above-mentioned calculation of the MU linearity value of the electron linear accelerator based on multiple target images may include:

[0084] Based on multiple target images, multiple target averages are calculated. The multiple target images include multiple groups of calculation images, and the MU values of the electron linear accelerator corresponding to the multiple groups of calculation images. Among them, the MU values corresponding to adjacent two groups of calculation images have a preset difference between the two MU values. The multiple target averages are the gray-scale averages of the multiple groups of calculation images;

[0085] The MU linear value is calculated through the multiple target averages and the MU values corresponding to the target averages.

[0086] Among them, the multiple target averages are the gray-scale averages of each group of calculation images in the multiple groups of calculation images.

[0087] Specifically, when calculating the multiple target averages, the following method can be used for calculation:

[0088]

[0089] In the formula, D ci represents the target average corresponding to the preset MU value, n represents the number of the multiple groups of calculation images obtained, and D cin represents the measured value corresponding to the preset MU value.

[0090] Among them, the MU values of the electron linear accelerator corresponding to adjacent two groups of calculation images, and there is a preset difference between the two MU values; for example, 5 groups of calculation images are acquired, and the MU values of the 5 groups of calculation images obtained can be 100 MU, 300 MU, 500 MU, 700 MU, and 900 MU in sequence, and 5 target averages of the 5 groups of calculation images can be obtained.

[0091] Specifically, the values of S and b can be obtained by using the least squares method with the multiple target averages obtained above, and then the following formula can be obtained:

[0092] D c = SU + b

[0093] In the formula, D c is the gray-scale value of the center point of the target image, S is the linear factor, U is the corresponding MU value, and b is the intercept of the straight line and the vertical coordinate.

[0094] The obtained D c , and then the MU linear value of the electron linear accelerator is calculated through the following formula:

[0095]

[0096] In the formula, D c is the obtained gray-scale value of the center point of the target image, D m is the measured gray-scale value corresponding to the corresponding MU value, and U m is corresponding to D cThe MU value.

[0097] Optionally, calculating the field flatness value of the electron linear accelerator based on a single target image includes:

[0098] Cropping the single target image according to a preset field width ratio to obtain a target cropped image corresponding to the single target image;

[0099] Calculating the maximum gray value and the minimum gray value in the target cropped image based on the target cropped image;

[0100] Calculating the field flatness value of the electron linear accelerator based on the maximum gray value and the minimum gray value. Calculating the field flatness value of the electron linear accelerator based on a single target image may include:

[0101] Cropping the single target image according to a preset field width ratio to obtain a target cropped image corresponding to the single target image;

[0102] Among them, cropping the single target image according to a preset field width ratio to obtain a target cropped image corresponding to the single target image, the preset field width ratio may be 0.8; for example, the set radiation field is 10*10 cm 2 , calculating the width of the target cropped image to be 8 cm through the preset field width of 0.8, that is, taking the range of 8*8 cm in the middle of the target image as the target cropped image. 2 as the target cropped image.

[0103] Calculating the maximum gray value and the minimum gray value in the target cropped image based on the target cropped image;

[0104] Among them, the maximum gray value D in the target cropped image can be calculated through the gray value calculation formula max and the minimum gray value D min . Among them, by traversing the gray value in the target cropped image, the maximum gray value D max and the minimum gray value D min can be obtained.

[0105] Calculating the field flatness value of the electron linear accelerator based on the maximum gray value and the minimum gray value.

[0106] Among them, the field flatness value can be obtained by the ratio of the maximum gray value and the minimum gray value, and it can be: Thus, the field flatness value of the electron linear accelerator can be obtained.

[0107] Optionally, calculating the field symmetry value of the electron linear accelerator based on a single target image may include:

[0108] Construct a plane rectangular coordinate system with the center point coordinates of a single target image;

[0109] According to the plane rectangular coordinate system, at least one set of target gray values is calculated. The target gray values include a first gray value and a second gray value, and the first gray value and the second gray value are symmetric with each other about the center of the plane rectangular coordinate system;

[0110] According to the first gray value and the second gray value, the field symmetry value of the electron linear accelerator is calculated.

[0111] Among them, after constructing a plane rectangular coordinate system with the center point coordinates of the target image, at least one set of target gray values is taken in the established plane rectangular coordinate system. For the first gray value and the second gray value in the target gray values, the first gray value and the second gray value are symmetric with each other about the center of the plane rectangular coordinate system.

[0112] Specifically, the field symmetry value can be calculated by the ratio of the first gray value and the second gray value, and it can be In the formula, x i represents the first gray value, x -i represents the second gray value, i is the i-th pixel point from the origin, and -i is the i-th pixel point in the opposite direction.

[0113] S3. Judge whether the MU linear value, the field flatness value, and the field symmetry value are respectively within their corresponding set requirement ranges;

[0114] Among them, by judging whether the MU linear value, the field flatness value, and the field symmetry value are respectively within their corresponding set requirement ranges, the results of whether the MU linear index, the field flatness index, and the field symmetry index of the electron linear accelerator are qualified are obtained.

[0115] Optionally, the set requirement range corresponding to the above MU linear value is a first set range, the set requirement range corresponding to the field flatness value is a second set range, and the set requirement range corresponding to the field symmetry value is a third set range; judging whether the MU linear value, the field flatness value, and the field symmetry value are respectively within their corresponding set requirement ranges includes:

[0116] Compare the MU linear value with the first set range. If the MU linear value is within the first set range, it is determined that the MU linear value is within the set requirement range corresponding to the MU linear value. If the MU linear value is not within the first set range, it is determined that the MU linear value is not within the set requirement range corresponding to the MU linear value;

[0117] Compare the field flatness value with the second set range. If the field flatness value is within the second set range, it is determined that the field flatness value is within the set requirement range corresponding to the field flatness value. If the field flatness value is not within the second set range, it is determined that the field flatness value is not within the set requirement range corresponding to the field flatness value;

[0118] Compare the field symmetry value with the third set range. If the field symmetry value is within the third set range, it is determined that the field symmetry value is within the set requirement range corresponding to the field symmetry value. If the field symmetry value is not within the third set range, it is determined that the field symmetry value is not within the set requirement range corresponding to the field symmetry value.

[0119] S4. If the MU linearity value, the field flatness value, and the field symmetry value are all within their respective corresponding set requirement ranges, obtain the first result that the MU linearity index, the field flatness index, and the field symmetry index of the electron linear accelerator are all qualified;

[0120] S5. If the MU linearity value is not within the corresponding set requirement range, obtain the second result that the MU linearity index of the electron linear accelerator is unqualified; if the field flatness value is not within the corresponding set requirement range, obtain the third result that the field flatness index of the electron linear accelerator is unqualified; if the field symmetry value is not within the corresponding set requirement range, obtain the fourth result that the field symmetry index of the electron linear accelerator is unqualified.

[0121] In a second aspect, an embodiment of the present application provides an EPID-based electron linear accelerator detection device, including:

[0122] An acquisition module for acquiring multiple EPID images of the EPID irradiating a target object multiple times, and taking each EPID image as a target image;

[0123] A calculation module for calculating the MU linearity value of the electron linear accelerator according to multiple target images, and also for calculating the field flatness value and the field symmetry value of the electron linear accelerator according to a single target image;

[0124] A judgment module for judging whether the MU linearity value, the field flatness value, and the field symmetry value are respectively within their respective corresponding set requirement ranges;

[0125] A qualification module for obtaining the first result that the MU linearity index, the field flatness index, and the field symmetry index of the electron linear accelerator are all qualified if the MU linearity value, the field flatness value, and the field symmetry value are all within their respective corresponding set requirement ranges;

[0126] The unqualified module is used to obtain the second result that the MU linearity index of the electron linear accelerator is unqualified if the MU linear value is not within the corresponding set requirement range; obtain the third result that the field flatness index of the electron linear accelerator is unqualified if the field flatness value is not within the corresponding set requirement range; obtain the fourth result that the field symmetry index of the electron linear accelerator is unqualified if the field symmetry value is not within the corresponding set requirement range.

[0127] Furthermore, the above calculation module includes:

[0128] The average value calculation unit is used to calculate and obtain the target average value of the central gray level of multiple target images;

[0129] The linear value calculation unit is used to calculate the MU linear value through the preset MU value of the electron linear accelerator corresponding to each target image and the target average value, where, for the MU values of the electron linear accelerator corresponding to two adjacent target images, the difference between the two MU values is a preset value;

[0130] The interception unit is used to intercept a single target image according to the preset ratio of the field width, and obtain the target intercepted image corresponding to the single target image;

[0131] The gray level value calculation unit is used to calculate and obtain the maximum gray level value and the minimum gray level value in the target intercepted image according to the target intercepted image;

[0132] The flatness value calculation unit is used to calculate and obtain the field flatness value of the electron linear accelerator according to the maximum gray level value and the minimum gray level value;

[0133] The construction unit is used to construct a plane rectangular coordinate system with the center point coordinates of a single target image;

[0134] The target gray level value calculation unit is used to calculate and obtain at least one group of target gray level values according to the plane rectangular coordinate system, the target gray level values include a first gray level value and a second gray level value, and the first gray level value and the second gray level value are symmetric with each other about the center of the plane rectangular coordinate system;

[0135] The symmetry value calculation unit is used to calculate and obtain the field symmetry value of the electron linear accelerator according to the first gray level value and the second gray level value.

[0136] Furthermore, the corresponding set requirement range of the above MU linear value is the first set range, the corresponding set requirement range of the field flatness value is the second set range, the corresponding set requirement range of the field symmetry value is the third set range, and the judgment module includes:

[0137] A linear value judgment unit is configured to compare the MU linear value with a first set range. If the MU linear value is within the first set range, it is determined that the MU linear value is within the set requirement range corresponding to the MU linear value; if the MU linear value is not within the first set range, it is determined that the MU linear value is not within the set requirement range corresponding to the MU linear value.

[0138] A flatness value judgment unit is configured to compare the field flatness value with a second set range. If the field flatness value is within the second set range, it is determined that the field flatness value is within the set requirement range corresponding to the field flatness value; if the field flatness value is not within the second set range, it is determined that the field flatness value is not within the set requirement range corresponding to the field flatness value.

[0139] A symmetry value judgment unit is configured to compare the field symmetry value with a third set range. If the field symmetry value is within the third set range, it is determined that the field symmetry value is within the set requirement range corresponding to the field symmetry value; if the field symmetry value is not within the third set range, it is determined that the field symmetry value is not within the set requirement range corresponding to the field symmetry value.

[0140] In a third aspect, an embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method according to any one of the first aspect is implemented.

[0141] In a fourth aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium, characterized in that the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the method according to any one of the first aspect.

[0142] For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present application is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. An EPID-based detection method for electron linear accelerators, characterized in that, Including the following steps: Collect multiple EPID images of the target object irradiated by the EPID multiple times, and use each of the EPID images as a target image; Based on the multiple target images, calculate the MU linear value of the linear accelerator, and based on a single target image, calculate the field flatness value and field symmetry value of the linear accelerator; Judge whether the MU linear value, the field flatness value, and the field symmetry value are respectively within their corresponding set requirement ranges; If the MU linear value, the field flatness value, and the field symmetry value are all within their corresponding set requirement ranges, obtain the first result that the MU linear index, the field flatness index, and the field symmetry index of the linear accelerator are all qualified; If the MU linear value is not within the corresponding set requirement range, obtain the second result that the MU linear index of the linear accelerator is unqualified; if the field flatness value is not within the corresponding set requirement range, obtain the third result that the field flatness index of the linear accelerator is unqualified; if the field symmetry value is not within the corresponding set requirement range, obtain the fourth result that the field symmetry index of the linear accelerator is unqualified; The calculating the MU linear value of the linear accelerator based on the multiple target images includes: Based on the multiple target images, calculate multiple target averages. The multiple target images include multiple groups of calculation images, and the MU values of the linear accelerator corresponding to the multiple groups of calculation images. Among them, the MU values corresponding to adjacent two groups of calculation images have a difference of a preset value between the two MU values. The multiple target averages are the gray-scale averages of the multiple groups of calculation images; Calculate the MU linear value through the multiple target averages and the MU values corresponding to the target averages; Among them, calculate the multiple target averages through the first formula, and the first formula is expressed as: ； In the formula, represents the target average value corresponding to the preset MU value, and n represents the number of groups of calculated images obtained; represents the measured value corresponding to the preset MU value; Calculate the values of S and b through the multiple target averages, and represent the relationship between the gray-scale value of the center point of the target image, S, and b through the second formula. The second formula is expressed as: ； In the formula, is the gray value of the center point of the target image, is the linear factor, is the corresponding MU value, is the intercept of the straight line and the vertical coordinate; Calculate the MU linear value of the linear accelerator through the third formula. The third formula is expressed as: ； In the formula, is the gray value of the center point of the target image obtained, is the measured gray value corresponding to the MU value, corresponds to is the MU value.

2. The method for detecting an electron linear accelerator based on an EPID according to claim 1, wherein The calculating the field flatness value of the linear accelerator based on a single target image includes: Intercept the single target image according to a preset field width ratio to obtain a target intercepted image corresponding to the single target image; Based on the target intercepted image, calculate the maximum gray-scale value and the minimum gray-scale value in the target intercepted image; Based on the maximum gray-scale value and the minimum gray-scale value, calculate the field flatness value of the linear accelerator; Among them, based on the maximum gray-scale value and the minimum gray-scale value, calculate the field flatness value of the linear accelerator. The field flatness value is calculated through the fourth formula, and the fourth formula is expressed as: ； In the formula, represents the maximum gray value, represents the minimum gray value.

3. The method for detecting an electron linear accelerator based on an EPID according to claim 1, characterized in that The calculating the field symmetry value of the linear accelerator based on a single target image includes: Construct a plane rectangular coordinate system with the center point coordinates of the single target image; According to the plane rectangular coordinate system, at least one set of target gray values is calculated and obtained. The target gray values include a first gray value and a second gray value, and the first gray value and the second gray value are symmetric with each other about the center of the plane rectangular coordinate system; According to the first gray value and the second gray value, the field symmetry value of the electron linear accelerator is calculated and obtained; Among them, for calculating and obtaining the field symmetry value of the electron linear accelerator according to the first gray value and the second gray value, the field symmetry value is calculated by a fifth formula, and the fifth formula is expressed as: ； In the formula, represents the first grayscale value, represents the second grayscale value, i is the i-th pixel point from the origin, and -i is the i-th pixel point in the opposite direction.

4. The method for detecting an electron linear accelerator based on an EPID according to claim 1, wherein The corresponding set requirement range of the MU linear value is a first set range, the corresponding set requirement range of the field flatness value is a second set range, and the corresponding set requirement range of the field symmetry value is a third set range; Judging whether each of the MU linear value, the field flatness value, and the field symmetry value is within its corresponding set requirement range includes: Comparing the MU linear value with the first set range. If the MU linear value is within the first set range, it is determined that the MU linear value is within the set requirement range corresponding to the MU linear value. If the MU linear value is not within the first set range, it is determined that the MU linear value is not within the set requirement range corresponding to the MU linear value; Comparing the field flatness value with the second set range. If the field flatness value is within the second set range, it is determined that the field flatness value is within the set requirement range corresponding to the field flatness value. If the field flatness value is not within the second set range, it is determined that the field flatness value is not within the set requirement range corresponding to the field flatness value; Comparing the field symmetry value with the third set range. If the field symmetry value is within the third set range, it is determined that the field symmetry value is within the set requirement range corresponding to the field symmetry value. If the field symmetry value is not within the third set range, it is determined that the field symmetry value is not within the set requirement range corresponding to the field symmetry value.

5. The EPID-based electron linear accelerator detection device is characterized in that, Including: An acquisition module, configured to acquire multiple EPID images of the EPID irradiating a target object multiple times, and use each EPID image as a target image; A calculation module, configured to calculate and obtain the MU linear value of the electron linear accelerator according to multiple target images, and is also configured to calculate and obtain the field flatness value and the field symmetry value of the electron linear accelerator according to a single target image; A judgment module, configured to judge whether each of the MU linear value, the field flatness value, and the field symmetry value is within its corresponding set requirement range; A qualified module, configured to, if the MU linear value, the field flatness value, and the field symmetry value are all within their corresponding set requirement ranges, obtain a first result that the MU linear index, the field flatness index, and the field symmetry index of the electron linear accelerator are all qualified; The unqualified module is used to obtain the second result that the MU linearity index of the electron linear accelerator is unqualified if the MU linear value is not within the corresponding set requirement range; to obtain the third result that the field flatness index of the electron linear accelerator is unqualified if the field flatness value is not within the corresponding set requirement range; and to obtain the fourth result that the field symmetry index of the electron linear accelerator is unqualified if the field symmetry value is not within the corresponding set requirement range. The calculating, based on the multiple target images, to obtain the MU linear value of the electron linear accelerator includes: Calculating multiple target averages based on the multiple target images. The multiple target images include multiple groups of calculation images, and the MU values of the electron linear accelerator corresponding to the multiple groups of calculation images. Among them, for the MU values corresponding to adjacent two groups of calculation images, the difference between the two MU values is a preset value. The multiple target averages are the gray-scale averages of the multiple groups of calculation images. Calculating the MU linear value through the multiple target averages and the MU values corresponding to the target averages. Among them, calculating the multiple target averages through the first formula, and the first formula is expressed as: ； Wherein, represents the target average value corresponding to the preset MU value, and n represents the number of groups of calculated images obtained; represents the measured value corresponding to the preset MU value; Calculating the values of S and b through the multiple target averages, and expressing the relationship between the gray-scale value of the center point of the target image, S and b through the second formula. The second formula is expressed as: ； In the formula, is the gray value of the center point of the target image, is the linear factor, is the corresponding MU value, is the intercept of the straight line and the vertical coordinate; Calculating the MU linear value of the electron linear accelerator through the third formula. The third formula is expressed as: ； Wherein, is the gray value of the calculated center point of the target image, is the measured gray value corresponding to the MU value, corresponds to is the MU value.

6. The EPID-based electron linear accelerator detection device according to claim 5, wherein, The calculation module includes: An average value calculation unit for calculating the target average of the central gray-scale of the multiple target images. A linear value calculation unit for calculating the MU linear value through the MU value preset for the electron linear accelerator corresponding to each target image and the target average. Among them, for the MU values of the electron linear accelerator corresponding to adjacent two target images, the difference between the two MU values is a preset value. An intercepting unit for intercepting a single target image according to a preset field width ratio to obtain a target intercepted image corresponding to the single target image. A gray-scale value calculation unit for calculating the maximum gray-scale value and the minimum gray-scale value in the target intercepted image according to the target intercepted image. A flatness value calculation unit for calculating the field flatness value of the electron linear accelerator according to the maximum gray-scale value and the minimum gray-scale value. A construction unit for constructing a plane rectangular coordinate system with the coordinate of the center point of a single target image. A target gray-scale value calculation unit for calculating at least one group of target gray-scale values according to the plane rectangular coordinate system. The target gray-scale values include a first gray-scale value and a second gray-scale value, and the first gray-scale value and the second gray-scale value are symmetric with each other along the center of the plane rectangular coordinate system. A symmetry value calculation unit for calculating the field symmetry value of the electron linear accelerator according to the first gray-scale value and the second gray-scale value.

7. The EPID-based electron linear accelerator detection device according to claim 5, wherein The setting requirement range corresponding to the MU linear value is the first setting range, the setting requirement range corresponding to the field flatness value is the second setting range, and the setting requirement range corresponding to the field symmetry value is the third setting range. The judgment module includes: A linear value judgment unit configured to compare the MU linear value with the first setting range. If the MU linear value is within the first setting range, it is determined that the MU linear value is within the setting requirement range corresponding to the MU linear value; if the MU linear value is not within the first setting range, it is determined that the MU linear value is not within the setting requirement range corresponding to the MU linear value. A flatness value judgment unit configured to compare the field flatness value with the second setting range. If the field flatness value is within the second setting range, it is determined that the field flatness value is within the setting requirement range corresponding to the field flatness value; if the field flatness value is not within the second setting range, it is determined that the field flatness value is not within the setting requirement range corresponding to the field flatness value. A symmetry value judgment unit configured to compare the field symmetry value with the third setting range. If the field symmetry value is within the third setting range, it is determined that the field symmetry value is within the setting requirement range corresponding to the field symmetry value; if the field symmetry value is not within the third setting range, it is determined that the field symmetry value is not within the setting requirement range corresponding to the field symmetry value.

8. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method described in any one of claims 1-4 is implemented.

9. A non-transitory computer-readable storage medium, characterized in that The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the method described in any one of claims 1-4.

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