CN116271569A - EPID-based electronic linear accelerator detection method, device, equipment and medium - Google Patents

EPID-based electronic linear accelerator detection method, device, equipment and medium Download PDF

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CN116271569A
CN116271569A CN202310122204.1A CN202310122204A CN116271569A CN 116271569 A CN116271569 A CN 116271569A CN 202310122204 A CN202310122204 A CN 202310122204A CN 116271569 A CN116271569 A CN 116271569A
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Abstract

The invention provides an EPID-based electronic linear accelerator detection method, an EPID-based electronic linear accelerator detection device, EPID-based electronic linear accelerator detection equipment and an EPID-based electronic linear accelerator detection medium, and relates to the field of electronic linear accelerator detection; the method comprises the following steps: collecting a plurality of EPID images of an EPID multi-time irradiation target object, and taking each EPID image as a target image; according to a plurality of target images, calculating to obtain MU linear values of the electronic linear accelerator, and according to a single target image, calculating to obtain a field flatness value and a field symmetry value of the electronic linear accelerator; judging whether the MU linear value, the portal flatness value and the portal symmetry value are respectively in the corresponding set requirement ranges or not; the imaging function of the EPID system is applied to the daily detection of the electronic linear accelerator, so that the daily detection efficiency of the electronic linear accelerator is greatly improved, the additionally purchased quality control equipment is not needed, and the daily detection cost is reduced.

Description

EPID-based electronic linear accelerator detection method, device, equipment and medium
Technical Field
The invention relates to the field of detection of electronic linear accelerators, in particular to a detection method, a detection device, a detection equipment and a detection medium of an electronic linear accelerator based on an EPID.
Background
Currently, radiotherapy has become one of the main means of tumor treatment, and as a main device of radiotherapy, the stability of the medical electronic linear accelerator directly influences the effect of radiotherapy, the daily detection of the electronic linear accelerator is a very important aspect of quality control, and the traditional daily detection of the electronic linear accelerator comprises detection of main indexes such as MU linearity, field flatness, field symmetry and the like; while the conventional detection apparatuses include an ionization chamber, a morning detector and a three-dimensional water tank, the conventional detection apparatuses are complicated and time-consuming to operate in the detection process of the daily accelerator, and meanwhile, the EPID apparatus has become an accelerator standard configuration apparatus, so that development of a daily detection method and device of the electronic linear accelerator based on EPID is needed.
Disclosure of Invention
The invention aims to provide an EPID-based electronic linear accelerator detection method, an EPID-based electronic linear accelerator detection device, EPID-based electronic linear accelerator detection equipment and an EPID-based electronic linear accelerator detection medium, so as to solve the problems in the background art.
Embodiments of the present invention are implemented as follows:
in a first aspect, an embodiment of the present application provides an EPID-based electronic linear accelerator detection method, including the steps of:
collecting a plurality of EPID images of the target object irradiated by the EPID for a plurality of times, and taking each EPID image as a target image;
according to the multiple target images, calculating to obtain MU linear values of the electronic linear accelerator, and according to the single target image, calculating to obtain the field flatness values and the field symmetry values of the electronic linear accelerator;
judging whether MU linear values, the portal flatness values and the portal symmetry values are in the corresponding set requirement ranges or not;
if the MU linear value, the field flatness value and the field symmetry value are in the corresponding set requirement ranges, obtaining a first result that the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are all qualified;
if the MU linear value is not in the corresponding set requirement range, obtaining a second result of unqualified MU linear index of the electronic linear accelerator; if the field flatness value is not in the corresponding set requirement range, obtaining a third result of disqualification of the field flatness index of the electronic linear accelerator; and if the field symmetry value is not in the corresponding set requirement range, obtaining a fourth result of disqualification of the field symmetry index of the electronic linear accelerator.
The beneficial effects of the invention are as follows: the imaging function of the EPID system is applied to the daily detection of the electronic linear accelerator, so that the daily detection efficiency of the electronic linear accelerator is greatly improved, the additionally purchased quality control equipment is not needed, and the daily detection cost is reduced.
On the basis of the technical scheme, the invention can be improved as follows.
Further, the calculating to obtain the MU linear value of the electronic linear accelerator according to the plurality of target images includes:
according to a plurality of target images, calculating to obtain a plurality of target average values, wherein the plurality of target images comprise a plurality of groups of calculated images, the plurality of groups of calculated images correspond to MU values of an electronic linear accelerator, the difference between the MU values corresponding to two adjacent groups of calculated images is a preset value, and the plurality of target average values are gray average values of the plurality of groups of calculated images;
calculating MU linear values through a plurality of target average values and MU values corresponding to the target average values;
wherein a plurality of the target averages are calculated by a first convention expressed as:
Figure BDA0004080357950000031
wherein D is ci Representing a target average value corresponding to a preset MU value, n represents the number for obtaining a plurality of groups of calculated images, D cin Representing a measured value corresponding to a preset MU value;
calculating the values of S and b through a plurality of target average values, and expressing the relation among the gray value of the center point of the target image, S and b through a second formula, wherein the second formula is expressed as follows:
D c ＝SU+b；
wherein D is c The gray value of the center point of the target image is represented by S, which is a linear factor, U is a corresponding MU value, and b is the intercept of the straight line and the ordinate;
the MU linear value of the electronic linear accelerator is obtained through calculation according to a third formula, wherein the third formula is expressed as:
Figure BDA0004080357950000032
wherein D is c D is the gray value of the center point of the target image m For the measured gray value corresponding to MU value, U m To correspond to D c MU value of (a).
The beneficial effects of adopting the further scheme are as follows: and obtaining the MU linear value of the electronic linear accelerator by the target average value and the MU value preset by the electronic linear accelerator when each target image is obtained.
Further, the calculating to obtain the field flatness value of the electron linac according to the image of the single Zhang Mubiao includes:
intercepting a single target image according to a preset portal width ratio to obtain a target intercepting image corresponding to the single target image;
according to the target cut-out graph, calculating to obtain a maximum gray value and a minimum gray value in the target cut-out graph;
according to the maximum gray value and the minimum gray value, calculating to obtain a field flatness value of the electronic linear accelerator;
according to the maximum gray level value and the minimum gray level value, calculating to obtain a portal flatness value of the electronic linear accelerator, wherein the portal flatness value is calculated through a fourth representation, and the fourth representation is as follows:
Figure BDA0004080357950000041
wherein D is max Represents the maximum gray value, D min Representing the minimum gray value.
The beneficial effects of adopting the further scheme are as follows: the calculated portal flatness value may be obtained by a ratio of a maximum gray value and a minimum gray value, whereby the portal flatness value of the electronic linear accelerator may be obtained.
Further, the calculating to obtain the field symmetry value of the electron linac according to the image of the single Zhang Mubiao includes:
constructing a plane rectangular coordinate system by using the center point coordinates of a single target image;
according to the plane rectangular coordinate system, calculating to obtain at least one group of target gray values, wherein the target gray values comprise a first gray value and a second gray value, and the first gray value and the second gray value are symmetrical along the center of the plane rectangular coordinate system;
according to the first gray value and the second gray value, calculating to obtain a field symmetry value of the electronic linear accelerator;
the method comprises the steps of obtaining a field symmetry value of the electronic linear accelerator through calculation according to the first gray value and the second gray value, wherein the field symmetry value is calculated through a fifth formula, and the fifth formula is expressed as:
Figure BDA0004080357950000042
wherein x is i Representing a first gray value, x -i And representing a second gray value, wherein i is the ith pixel point from the original point, and i is the ith pixel point in the opposite direction.
The beneficial effects of adopting the further scheme are as follows: at least one group of target gray values are taken from the established plane rectangular coordinate system, and 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 symmetrical to each other along the center of the plane rectangular coordinate system, and the field symmetry value of the electronic linear accelerator is obtained through the first gray value and the second gray value.
Further, the set requirement range corresponding to the 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 portal flatness value and the portal symmetry value are respectively in the corresponding set requirement ranges or not comprises the following steps:
comparing the MU linear value with a first set range, if the MU linear value is in the first set range, judging that the MU linear value is in a set request range corresponding to the MU linear value, and if the MU linear value is not in the first set range, judging that the MU linear value is not in the set request range corresponding to the MU linear value;
comparing the field flatness value with a second set range, if the field flatness value is within the second set range, judging that the field flatness value is within a set request range corresponding to the field flatness value, and if the field flatness value is not within the second set range, judging that the field flatness value is not within the set request range corresponding to the field flatness value;
and comparing the field symmetry value with a third setting range, if the field symmetry value is within the third setting range, judging that the field symmetry value is within the setting requirement range corresponding to the field symmetry value, and if the field symmetry value is not within the third setting range, judging that the field symmetry value is not within the setting requirement range corresponding to the field symmetry value.
The beneficial effects of adopting the further scheme are as follows: and obtaining whether the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are qualified or not.
In a second aspect, embodiments of the present application provide an EPID-based electronic linear accelerator detection device, comprising:
the acquisition module is used for acquiring a plurality of EPID images of the target object irradiated by the EPID for a plurality of times, and taking each EPID image as a target image;
the calculation module is used for calculating and obtaining MU linear values of the electronic linear accelerator according to the plurality of target images and also used for calculating and obtaining the field flatness values and the field symmetry values of the electronic linear accelerator according to the single Zhang Mubiao image;
the judging module is used for judging whether the MU linear value, the portal flatness value and the portal symmetry value are respectively in the corresponding set requirement range;
the qualification module is used for obtaining a first result that the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are qualified if the MU linear value, the field flatness value and the field symmetry value are all in the corresponding set requirement ranges;
the disqualification module is used for obtaining a second result of disqualification of the MU linear index of the electronic linear accelerator if the MU linear value is not in the corresponding set requirement range; if the field flatness value is not in the corresponding set requirement range, obtaining a third result of disqualification of the field flatness index of the electronic linear accelerator; and if the field symmetry value is not in the corresponding set requirement range, obtaining a fourth result of disqualification of the field symmetry index of the electronic linear accelerator.
Further, the calculation module includes:
an average value calculation unit for calculating a target average value of center grayscales of the plurality of target images;
the linear value calculating unit is used for calculating an MU linear value by comparing the preset MU value of the electronic linear accelerator with the target average value of each target image, wherein the difference between the MU values of the electronic linear accelerators corresponding to two adjacent target images is a preset value;
the intercepting unit is used for intercepting the single target image according to the preset portal width proportion ratio to obtain a target intercepting image corresponding to the single target image;
the gray value calculation unit is used for calculating and obtaining the maximum gray value and the minimum gray value in the target cut-out graph according to the target cut-out graph;
the flatness value calculation unit is used for calculating and obtaining the radiation field flatness value of the electronic linear accelerator according to the maximum gray value and the minimum gray value;
the construction unit is used for constructing a plane rectangular coordinate system by using the center point coordinates of the single target image;
the target gray value calculation unit is used for calculating and obtaining at least one group of target gray values according to the plane rectangular coordinate system, wherein the target gray values comprise a first gray value and a second gray value, and the first gray value and the second gray value are symmetrical along the center of the plane rectangular coordinate system;
and the symmetry value calculation unit is used for calculating and obtaining the field symmetry value of the electronic linear accelerator according to the first gray value and the second gray value.
Further, the setting request range corresponding to the MU linear value is a first setting range, the setting request range corresponding to the field flatness value is a second setting range, the setting request range corresponding to the field symmetry value is a third setting range, and the judging module includes:
the linear value judging unit is used for comparing the MU linear value with the first set range, judging that the MU linear value is in the set request range corresponding to the MU linear value if the MU linear value is in the first set range, and judging that the MU linear value is not in the set request range corresponding to the MU linear value if the MU linear value is not in the first set range;
a flatness value judging unit, configured to compare the field flatness value with a second set range, determine that the field flatness value is within a set required range corresponding to the field flatness value if the field flatness value is within the second set range, and determine that the field flatness value is not within the set required range corresponding to the field flatness value if the field flatness value is not within the second set range;
and the symmetry value judging unit is used for comparing the field symmetry value with a third set range, judging that the field symmetry value is in a set requirement range corresponding to the field symmetry value if the field symmetry value is in the third set range, and judging that the field symmetry value is not in the set requirement range corresponding to the field symmetry value if the field symmetry value is not in the third set range.
In a third aspect, embodiments of the present application provide an electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method of any one of the first aspects when executing the computer program.
In a fourth aspect, embodiments of the present application provide a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions that cause a computer to perform the method of any one of the first aspects.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for detecting an electronic linear accelerator according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing connection of an electronic linear accelerator detection device according to an embodiment of the present invention;
fig. 3 is a schematic connection diagram of an electronic device according to an embodiment of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Examples
In a first aspect, the present embodiment provides an EPID-based electronic linear accelerator detection method, including the steps of:
s1, acquiring a plurality of EPID images of an EPID multi-time irradiation target object, and taking each EPID image as a target image;
the EPID is a real-time image verification system, also called an electronic portal imaging system (EPID), and the EPID system consists of two parts of ray detection and computer processing of ray signals; the differences in the different systems are mainly manifested in the former part, which is the same or similar for all systems; the system verifies the positions of radiation treatment before and during the treatment of a patient, and verifies the geometric accuracy of the patient positioning irradiation field by matching the irradiation field image with a digital reconstruction image generated by an analog locating plate or a treatment planning system; according to the scheme, through the imaging function of the EPID system, the purposes of verifying the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are achieved through the obtained EPID image.
Specifically, before acquiring an EPID image, the position of an EPID plate of the EPID system needs to be adjusted, that is, by moving the EPID plate, it is ensured that the center of the EPID plate and the center of the field of the electronic linac are at the same point, and the center of the field of the electronic linac refers to the center point of the irradiation field formed on the center plane after the tungsten gate of the electronic linac is opened.
The target object in the target image is a process of detecting the electronic linear accelerator, so the target object can be an environment or a human body model, namely the content in the target image is indefinite.
S2, calculating to obtain MU linear values of the electronic linear accelerator according to the multiple target images, and calculating to obtain the field flatness values and the field symmetry values of the electronic linear accelerator according to the single target image;
wherein, when calculating MU linear value of the electronic linear accelerator, a plurality of target images are needed to pass; in the case of calculating the field flatness value and the field symmetry value of the electronic linear accelerator, the calculation may be performed by a single target image.
Optionally, the calculating to obtain the MU linear value of the electronic linear accelerator according to the multiple target images may include:
according to a plurality of target images, calculating to obtain a plurality of target average values, wherein the plurality of target images comprise a plurality of groups of calculated images, the plurality of groups of calculated images correspond to MU values of an electronic linear accelerator, the difference between the MU values corresponding to two adjacent groups of calculated images is a preset value, and the plurality of target average values are gray average values of the plurality of groups of calculated images;
and calculating the MU linear value through the target average values and the MU value corresponding to the target average values.
The target average values are the gray average values of each group of calculated images in the plurality of groups of calculated images.
Specifically, the calculation of the plurality of target average values may be performed by:
Figure BDA0004080357950000101
wherein D is ci Representing a target average value corresponding to a preset MU value, n represents the number for obtaining a plurality of groups of calculated images, D cin Representing the measured value corresponding to the preset MU value.
The method comprises the steps of calculating MU values of electronic linear accelerators corresponding to images in two adjacent groups, wherein the difference between the MU values is a preset value; for example, 5 sets of calculated images are acquired, and MU values of the 5 sets of calculated images obtained may be 100MU, 300MU, 500MU, 700MU, and 900MU in this order, and 5 target average values of the 5 sets of calculated images may be obtained.
Specifically, the values of S and b can be obtained by the least square method through the plurality of target averages obtained above, and the following formula can be obtained:
D c ＝SU+b
wherein D is c And S is a linear factor, U is a corresponding MU value, and b is the intercept of the straight line and the ordinate.
D obtained by calculation c Then the electronic linear accelerator is obtained through the calculation of the following formulaMU linear value:
Figure BDA0004080357950000111
wherein D is c D is the gray value of the center point of the target image m For the measured gray value corresponding to MU value, U m To correspond to D c MU value of (a).
Optionally, the calculating to obtain the field flatness value of the electronic linear accelerator according to the image of the single Zhang Mubiao includes:
intercepting a single target image according to a preset portal width ratio to obtain a target intercepting image corresponding to the single target image;
according to the target cut-out graph, calculating to obtain a maximum gray value and a minimum gray value in the target cut-out graph;
and calculating to obtain the spot flatness value of the electronic linear accelerator according to the maximum gray value and the minimum gray value. According to a single target image, calculating and obtaining the field flatness value of the electronic linear accelerator can comprise the following steps:
intercepting a single target image according to a preset portal width ratio to obtain a target intercepting image corresponding to the single target image;
the method comprises the steps of intercepting a single target image through a preset portal width ratio to obtain a target intercepting image corresponding to the single target image, wherein the preset portal width ratio can be 0.8; for example, the radiation field is 10 x 10cm 2 The width of the target cut-out image is calculated to be 8cm through the preset radiation field width of 0.8, namely 8cm is taken as the middle target image of the target image 2 Is the target cut-out.
According to the target cut-out graph, calculating to obtain a maximum gray value and a minimum gray value in the target cut-out graph;
wherein, the maximum gray value D in the target cut-out graph can be calculated and obtained through a gray calculation formula max And a minimum gray value D min . Traversing the gray value in the target intercept graph to obtain the maximum gray value D max And a minimum gray value D min 。
And calculating to obtain the spot flatness value of the electronic linear accelerator according to the maximum gray value and the minimum gray value.
The calculated field flatness value may be obtained by a ratio of a maximum gray value to a minimum gray value, and may be:
Figure BDA0004080357950000121
thereby, the field flatness value of the electron linac can be obtained.
Optionally, the calculating to obtain the field symmetry value of the electronic linear accelerator according to the image of the single Zhang Mubiao may include:
constructing a plane rectangular coordinate system by using the center point coordinates of a single target image;
according to the plane rectangular coordinate system, calculating to obtain at least one group of target gray values, wherein the target gray values comprise a first gray value and a second gray value, and the first gray value and the second gray value are symmetrical along the center of the plane rectangular coordinate system;
and calculating to obtain the field symmetry value of the electronic linear accelerator according to the first gray value and the second gray value.
After a plane rectangular coordinate system is built by using the center point coordinates of the target image, at least one group of target gray values are taken from the built plane rectangular coordinate system, and the first gray value and the second gray value in the target gray values are symmetrical along the center of the plane rectangular coordinate system.
Specifically, the field symmetry value may be calculated by a ratio of the first gray value to the second gray value, and may be
Figure BDA0004080357950000122
Wherein x is i Representing a first gray value, x -i And representing a second gray value, wherein i is the ith pixel point from the original point, and i is the ith pixel point in the opposite direction.
S3, judging whether the MU linear value, the field flatness value and the field symmetry value are respectively in the corresponding set requirement ranges;
and judging whether the MU linear value, the field flatness value and the field symmetry value are in the respective corresponding set requirement ranges, so as to obtain the result of whether the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are qualified.
Optionally, the set requirement range corresponding to the 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 portal flatness value and the portal symmetry value are respectively in the corresponding set requirement ranges or not comprises the following steps:
comparing the MU linear value with a first set range, if the MU linear value is in the first set range, judging that the MU linear value is in a set request range corresponding to the MU linear value, and if the MU linear value is not in the first set range, judging that the MU linear value is not in the set request range corresponding to the MU linear value;
comparing the field flatness value with a second set range, if the field flatness value is within the second set range, judging that the field flatness value is within a set request range corresponding to the field flatness value, and if the field flatness value is not within the second set range, judging that the field flatness value is not within the set request range corresponding to the field flatness value;
and comparing the field symmetry value with a third setting range, if the field symmetry value is within the third setting range, judging that the field symmetry value is within the setting requirement range corresponding to the field symmetry value, and if the field symmetry value is not within the third setting range, judging that the field symmetry value is not within the setting requirement range corresponding to the field symmetry value.
S4, if the MU linear value, the field flatness value and the field symmetry value are in the corresponding set requirement ranges, obtaining a first result that the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are all qualified;
s5, if the MU linear value is not in the corresponding set requirement range, obtaining a second result of disqualification of the MU linear index of the electronic linear accelerator; if the field flatness value is not in the corresponding set requirement range, obtaining a third result of disqualification of the field flatness index of the electronic linear accelerator; and if the field symmetry value is not in the corresponding set requirement range, obtaining a fourth result of disqualification of the field symmetry index of the electronic linear accelerator.
In a second aspect, embodiments of the present application provide an EPID-based electronic linear accelerator detection device, comprising:
the acquisition module is used for acquiring a plurality of EPID images of the target object irradiated by the EPID for a plurality of times, and taking each EPID image as a target image;
the calculation module is used for calculating and obtaining MU linear values of the electronic linear accelerator according to the plurality of target images and also used for calculating and obtaining the field flatness values and the field symmetry values of the electronic linear accelerator according to the single Zhang Mubiao image;
the judging module is used for judging whether the MU linear value, the portal flatness value and the portal symmetry value are respectively in the corresponding set requirement range;
the qualification module is used for obtaining a first result that the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are qualified if the MU linear value, the field flatness value and the field symmetry value are all in the corresponding set requirement ranges;
the disqualification module is used for obtaining a second result of disqualification of the MU linear index of the electronic linear accelerator if the MU linear value is not in the corresponding set requirement range; if the field flatness value is not in the corresponding set requirement range, obtaining a third result of disqualification of the field flatness index of the electronic linear accelerator; and if the field symmetry value is not in the corresponding set requirement range, obtaining a fourth result of disqualification of the field symmetry index of the electronic linear accelerator.
Further, the calculation module includes:
an average value calculation unit for calculating a target average value of center grayscales of the plurality of target images;
the linear value calculating unit is used for calculating an MU linear value by comparing the preset MU value of the electronic linear accelerator with the target average value of each target image, wherein the difference between the MU values of the electronic linear accelerators corresponding to two adjacent target images is a preset value;
the intercepting unit is used for intercepting the single target image according to the preset portal width proportion ratio to obtain a target intercepting image corresponding to the single target image;
the gray value calculation unit is used for calculating and obtaining the maximum gray value and the minimum gray value in the target cut-out graph according to the target cut-out graph;
the flatness value calculation unit is used for calculating and obtaining the radiation field flatness value of the electronic linear accelerator according to the maximum gray value and the minimum gray value;
the construction unit is used for constructing a plane rectangular coordinate system by using the center point coordinates of the single target image;
the target gray value calculation unit is used for calculating and obtaining at least one group of target gray values according to the plane rectangular coordinate system, wherein the target gray values comprise a first gray value and a second gray value, and the first gray value and the second gray value are symmetrical along the center of the plane rectangular coordinate system;
and the symmetry value calculation unit is used for calculating and obtaining the field symmetry value of the electronic linear accelerator according to the first gray value and the second gray value.
Further, the setting request range corresponding to the MU linear value is a first setting range, the setting request range corresponding to the field flatness value is a second setting range, the setting request range corresponding to the field symmetry value is a third setting range, and the judging module includes:
the linear value judging unit is used for comparing the MU linear value with the first set range, judging that the MU linear value is in the set request range corresponding to the MU linear value if the MU linear value is in the first set range, and judging that the MU linear value is not in the set request range corresponding to the MU linear value if the MU linear value is not in the first set range;
a flatness value judging unit, configured to compare the field flatness value with a second set range, determine that the field flatness value is within a set required range corresponding to the field flatness value if the field flatness value is within the second set range, and determine that the field flatness value is not within the set required range corresponding to the field flatness value if the field flatness value is not within the second set range;
and the symmetry value judging unit is used for comparing the field symmetry value with a third set range, judging that the field symmetry value is in a set requirement range corresponding to the field symmetry value if the field symmetry value is in the third set range, and judging that the field symmetry value is not in the set requirement range corresponding to the field symmetry value if the field symmetry value is not in the third set range.
In a third aspect, embodiments of the present application provide an electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method of any one of the first aspects when executing the computer program.
In a fourth aspect, embodiments of the present application provide a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions that cause a computer to perform the method of any one of the first aspects.
It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (10)

1. The electronic linear accelerator detection method based on the EPID is characterized by comprising the following steps of:
collecting a plurality of EPID images of an EPID multi-time irradiation target object, and taking each EPID image as a target image;
according to a plurality of target images, calculating to obtain MU linear values of the electronic linear accelerator, and according to a single target image, calculating to obtain a field flatness value and a field symmetry value of the electronic linear accelerator;
judging whether the MU linear value, the portal flatness value and the portal symmetry value are respectively in the corresponding set requirement ranges or not;
if the MU linear value, the field flatness value and the field symmetry value are in the corresponding set requirement ranges, obtaining a first result that the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are all qualified;
if the MU linear value is not in the corresponding set requirement range, a second result that the MU linear index of the electronic linear accelerator is unqualified is obtained; if the field flatness value is not in the corresponding set requirement range, obtaining a third result of disqualification of the field flatness index of the electronic linear accelerator; and if the field symmetry value is not in the corresponding set requirement range, obtaining a fourth result of disqualification of the field symmetry index of the electronic linear accelerator.
2. The EPID-based electronic linear accelerator detection method according to claim 1, wherein the calculating to obtain MU linear values of the electronic linear accelerator from a plurality of the target images includes:
calculating to obtain a plurality of target average values according to a plurality of target images, wherein the plurality of target images comprise a plurality of groups of calculated images, and the plurality of groups of calculated images correspond to MU values of an electronic linear accelerator, wherein the difference between the MU values corresponding to two adjacent groups of calculated images is a preset value, and the plurality of target average values are gray average values of the plurality of groups of calculated images;
calculating the MU linear value through a plurality of target average values and MU values corresponding to the target average values;
wherein a plurality of the target averages are calculated by a first convention expressed as:
Figure FDA0004080357940000021
wherein D is ci Representing a target average value corresponding to a preset MU value, n represents the number for obtaining a plurality of groups of calculated images, D cin Representing a measured value corresponding to a preset MU value;
calculating the values of S and b through a plurality of target average values, and expressing the relation among the gray value of the center point of the target image, S and b through a second formula, wherein the second formula is expressed as follows:
D c ＝SU+b；
wherein D is c The gray value of the center point of the target image is represented by S, which is a linear factor, U is a corresponding MU value, and b is the intercept of the straight line and the ordinate;
the MU linear value of the electronic linear accelerator is obtained through calculation according to a third formula, wherein the third formula is expressed as:
Figure FDA0004080357940000022
wherein D is c D is the gray value of the center point of the target image m For the measured gray value corresponding to MU value, U m To correspond to D c MU value of (a).
3. The EPID-based electronic linear accelerator detection method according to claim 1, wherein calculating a field flatness value of the electronic linear accelerator from the single target image comprises:
intercepting a single target image according to a preset portal width proportion ratio to obtain a target intercepting diagram corresponding to the single target image;
according to the target interception graph, calculating to obtain a maximum gray value and a minimum gray value in the target interception graph;
according to the maximum gray value and the minimum gray value, calculating to obtain a portal flatness value of the electronic linear accelerator;
according to the maximum gray level value and the minimum gray level value, calculating to obtain a portal flatness value of the electronic linear accelerator, wherein the portal flatness value is calculated through a fourth representation, and the fourth representation is as follows:
Figure FDA0004080357940000031
wherein D is max Represents the maximum gray value, D min Representing the minimum gray value.
4. The EPID-based detection method of electronic linear accelerator according to claim 1, wherein calculating a field symmetry value of the electronic linear accelerator from a single target image comprises:
constructing a plane rectangular coordinate system by using the center point coordinates of the single target image;
calculating to obtain at least one group of target gray values according to the plane rectangular coordinate system, wherein the target gray values comprise a first gray value and a second gray value, and the first gray value and the second gray value are symmetrical to each other along the center of the plane rectangular coordinate system;
according to the first gray value and the second gray value, calculating to obtain a field symmetry value of the electronic linear accelerator;
the method comprises the steps of obtaining a field symmetry value of the electronic linear accelerator through calculation according to the first gray value and the second gray value, wherein the field symmetry value is calculated through a fifth formula, and the fifth formula is expressed as:
Figure FDA0004080357940000032
wherein x is i Representing a first gray value, x -i And representing a second gray value, wherein i is the ith pixel point from the original point, and i is the ith pixel point in the opposite direction.
5. The EPID-based electronic linear accelerator detection method according to claim 1, wherein the setting request range corresponding to the MU linear value is a first setting range, the setting request range corresponding to the portal flatness value is a second setting range, and the setting request range corresponding to the portal symmetry value is a third setting range; the determining whether the MU linear value, the portal flatness value, and the portal symmetry value are within the respective corresponding set requirement ranges includes:
comparing the MU linear value with the first set range, if the MU linear value is in the first set range, judging that the MU linear value is in a set request range corresponding to the MU linear value, and if the MU linear value is not in the first set range, judging that the MU linear value is not in the set request 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, determining that the field flatness value is within a set required range corresponding to the field flatness value, and if the field flatness value is not within the second set range, determining that the field flatness value is not within the set required range corresponding to the field flatness value;
and comparing the field symmetry value with the third set range, if the field symmetry value is within the third set range, determining that the field symmetry value is within a set requirement range corresponding to the field symmetry value, and if the field symmetry value is not within the third set range, determining that the field symmetry value is not within the set requirement range corresponding to the field symmetry value.
6. An EPID-based electronic linear accelerator detection device comprising:
the acquisition module is used for acquiring a plurality of EPID images of the target object irradiated by the EPID for a plurality of times, and taking each EPID image as a target image;
the calculation module is used for calculating and obtaining MU linear values of the electronic linear accelerator according to a plurality of target images, and calculating and obtaining the field flatness values and the field symmetry values of the electronic linear accelerator according to a single target image;
the judging module is used for judging whether the MU linear value, the portal flatness value and the portal symmetry value are respectively in the corresponding set requirement range or not;
the qualification module is used for obtaining a first result that the MU linear index, the field flatness index and the field symmetry index of the electronic linear accelerator are qualified if the MU linear value, the field flatness value and the field symmetry value are all in the respective corresponding set requirement ranges;
the disqualification module is used for obtaining a second result of disqualification of the MU linear index of the electronic linear accelerator if the MU linear value is not in the corresponding set requirement range; if the field flatness value is not in the corresponding set requirement range, obtaining a third result of disqualification of the field flatness index of the electronic linear accelerator; and if the field symmetry value is not in the corresponding set requirement range, obtaining a fourth result of disqualification of the field symmetry index of the electronic linear accelerator.
7. The EPID based electronic linac detection device according to claim 6, characterized in that the calculation module comprises:
an average value calculation unit configured to calculate a target average value of center grayscales of the plurality of target images;
the linear value calculating unit is used for calculating the MU linear value through the preset MU value of the electronic linear accelerator corresponding to each target image and the target average value, wherein the difference between the MU values of the electronic linear accelerators corresponding to two adjacent target images is a preset value;
the intercepting unit is used for intercepting a single target image according to the preset portal width proportion ratio to obtain a target intercepting image corresponding to the single target image;
the gray value calculation unit is used for calculating and obtaining a maximum gray value and a minimum gray value in the target cut-out graph according to the target cut-out graph;
a flatness value calculation unit, configured to calculate and obtain a field flatness value of the electronic linear accelerator according to the maximum gray value and the minimum gray value;
the construction unit is used for constructing a plane rectangular coordinate system according to the center point coordinates of the single target image;
the target gray value calculation unit is used for calculating and obtaining at least one group of target gray values according to the plane rectangular coordinate system, wherein the target gray values comprise a first gray value and a second gray value, and the first gray value and the second gray value are symmetrical along the center of the plane rectangular coordinate system;
and the symmetry value calculation unit is used for calculating and obtaining the field symmetry value of the electronic linear accelerator according to the first gray value and the second gray value.
8. The EPID-based electronic linear accelerator detection device according to claim 6, wherein the setting request range corresponding to the MU linear value is a first setting range, the setting request range corresponding to the field flatness value is a second setting range, the setting request range corresponding to the field symmetry value is a third setting range, and the judging module comprises:
a linear value judging unit, configured to compare the MU linear value with the first set range, determine that the MU linear value is in a set requirement range corresponding to the MU linear value if the MU linear value is in the first set range, and determine that the MU linear value is not in the set requirement range corresponding to the MU linear value if the MU linear value is not in the first set range;
a flatness value determining unit, configured to compare the field flatness value with the second set range, determine that the field flatness value is within a set required range corresponding to the field flatness value if the field flatness value is within the second set range, and determine that the field flatness value is not within a set required range corresponding to the field flatness value if the field flatness value is not within the second set range;
and the symmetry value judging unit is used for comparing the field symmetry value with the third setting range, judging that the field symmetry value is in the setting requirement range corresponding to the field symmetry value if the field symmetry value is in the third setting range, and judging that the field symmetry value is not in the setting requirement range corresponding to the field symmetry value if the field symmetry value is not in the third setting range.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method of any one of claims 1-5 when the computer program is executed by the processor.
10. A non-transitory computer readable storage medium storing computer instructions that cause a computer to perform the method of any one of claims 1-5.
CN202310122204.1A 2023-02-06 2023-02-06 EPID-based electronic linear accelerator detection method, device, equipment and medium Pending CN116271569A (en)

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