CN-121971809-A - Detector calibration method, device, medium and equipment applied to radiotherapy

CN121971809ACN 121971809 ACN121971809 ACN 121971809ACN-121971809-A

Abstract

The specification discloses a method, a device, a medium and equipment for calibrating a detector applied to radiotherapy, and relates to the technical field of medical equipment calibration. Dark flat field reference data, bright flat field reference data, dose response data, field correction data, phantom correction data, off-axis correction data, and artifact correction data may be obtained. The artifact correction data comprise a seventh gray value obtained after each irradiation is finished after the detector is irradiated by rays for a plurality of preset time periods respectively, and an eighth gray value obtained after artifact is disappeared. And determining the calibration dosage values corresponding to different gray values of the detector respectively according to the data. Therefore, the electronic equipment calibrates the detector based on the artifact data, the dose response data and other data, reduces the influence of the artifact, the dose change and other factors on the detector, and improves the accuracy of the detector.

Inventors

LIU LIYE
LIU ZHAOXING
LIU XIN
SHI ZHONGYAN
JIN HAIJING
LIANG RUNCHENG
ZHAO RI
LI HUA
CHEN FAGUO
YANG BIAO
GUO RONG
ZHANG JING

Assignees

中国辐射防护研究院

Dates

Publication Date: 20260505
Application Date: 20260212

Claims (14)

1. A method for calibrating a detector for radiation therapy, comprising: The method comprises the steps of acquiring dark flat field reference data, bright flat field reference data, dose response data, radiation field correction data, die body correction data, off-axis correction data and artifact correction data, wherein the dark flat field reference data comprises a dark flat field radiation value and a first gray value acquired by each target point of a detector in a dark flat field, the bright flat field reference data comprises a bright flat field radiation value and a second gray value acquired by each target point of the detector in a bright flat field, the dose response data comprises a reference radiation value and a third gray value which are respectively acquired when the detector is in a plurality of preset reference radiation fields, the radiation field correction data comprises a radiation field radiation value and a fourth gray value which are respectively acquired when the detector corresponds to a plurality of preset radiation field areas, and the die body correction data comprises a die body radiation value and a fifth gray value which are respectively acquired when a plurality of preset thickness die bodies are arranged between the detector and a transmitting source; And determining the calibration dosage values respectively corresponding to different gray scale values of the detector according to the dark flat field reference data, the bright flat field reference data, the dosage response data, the radiation field correction data, the die body correction data, the off-axis correction data and the artifact correction data.
2. The method of claim 1, wherein determining the calibrated dose value for each of the different gray scale values of the detector based on the dark-flat-field reference data, the bright-flat-field reference data, the dose response data, the field correction data, the off-axis correction data of the phantom, and the artifact correction data comprises: According to the dark flat field reference data and the bright flat field reference data, determining a corrected gray value according to the gray value acquired by any one target point; And determining a calibration dose value corresponding to different gray values of a target point in the detector according to the corrected gray value, the dose response data, the field correction data, the off-axis correction data of the die body and the artifact correction data.
3. The method for calibrating a detector for radiation therapy according to claim 2, wherein determining a corrected gray value for a gray value acquired for any one target point based on the dark flat field reference data and the bright flat field reference data comprises: According to the dark flat field reference data and the bright flat field reference data, aiming at the gray value acquired by any target point, determining a corrected gray value according to the following formula: Wherein, the Corrected gray values for the target points (x, y); gray values acquired for the target point (x, y); for the first gray value corresponding to the target point (x, y) in the dark flat field reference data, A second gray value corresponding to the target point (x, y) in the bright flat field reference data; The average value of the second gray values corresponding to all target points (x, y) in the bright flat field reference data; And the average value of the first gray values corresponding to all target points (x, y) in the dark flat field reference data.
4. The method for calibrating a detector for use in radiation therapy according to claim 2, wherein before determining the calibration dose value corresponding to each of the different gray scale values of the target point in the detector, the method further comprises: Determining a dose-modifying parameter from the dose-response data; determining a radiation field correction parameter according to the radiation field correction data and the dose correction parameter; determining a die body correction parameter according to the die body correction data and the dose correction parameter; Determining an off-axis correction parameter according to the off-axis correction data and the dose correction parameter; and determining an artifact correction parameter according to the artifact correction data.
5. The method according to claim 4, wherein determining, for any one target point, a calibration dose value corresponding to a different gray value of the target point in the detector according to the corrected gray value, the dose response data, the field correction data, the off-axis correction data of the phantom, and the artifact correction data, respectively, comprises: according to the corrected gray value, the dose response data, the radiation field correction data, the off-axis correction data of the die body and the artifact correction data, for any one target point, determining the calibrated dose value corresponding to different gray values of the target point in the detector respectively through the following formula: Wherein, the Is the target point At a gray value of The corresponding calibrated dosage value; is the target point C is the dose correction parameter; correcting parameters for the portal; Correcting parameters for the die body; Correcting parameters for the off-axis; and correcting parameters for the artifact.
6. A method of calibrating a detector for use in radiation therapy according to claim 4, wherein said determining a dose-modifying parameter based on said dose-response data comprises: When any reference radiation field is generated, a reference radiation value and a third gray value are respectively acquired, and a dose correction value under the radiation dose corresponding to the reference radiation field is determined through the following formula: Wherein, the Is a dose correction value; a reference radiation value corresponding to the reference radiation field; the average value of the third gray values acquired by all target points when the detector is in the reference radiation field; and determining a dose correction parameter through an interpolation algorithm according to the dose correction value and the reference radiation value respectively corresponding to the reference radiation fields.
7. The method of claim 6, wherein determining the radiation field correction parameters based on the radiation field correction data and the dose correction parameters comprises: When the detector corresponds to a plurality of preset field areas respectively, a field radiation value and a fourth gray value are obtained respectively, and a corresponding field correction value of any one preset field area is determined through the following formula: Wherein, the A corresponding field correction value for the predetermined field area; a portal radiation value corresponding to the preset portal area; The average value of the fourth gray value of each target point corresponding to the preset field area is obtained; Correcting parameters for the dose; And determining the field correction parameters through an interpolation algorithm according to the dose correction values respectively corresponding to the plurality of preset field areas.
8. The method of calibrating a detector for radiation therapy according to claim 6, wherein said determining a phantom correction parameter based on said phantom correction data and said dose correction parameter comprises: when a plurality of die bodies with preset thickness are arranged between the detector and the emission source, a die body radiation value and a fifth degree value are respectively obtained, and a die body correction value corresponding to any die body with preset thickness is determined through the following formula: Wherein, the A die body correction value corresponding to the die body with the preset thickness; A die body radiation value corresponding to the die body with the preset thickness; the average value of the fifth gray value of each target point corresponding to the die body with the preset thickness is obtained; Correcting parameters for the dose; and determining die body correction parameters through an interpolation algorithm according to die body correction values respectively corresponding to a plurality of die bodies with preset thicknesses.
9. The method of claim 6, wherein determining the off-axis correction parameters based on the off-axis correction data and the dose correction parameters comprises: When the off-axis distance of the detector is a plurality of preset off-axis distances, respectively acquiring an off-axis radiation value and a sixth gray value, and determining an off-axis correction value corresponding to any one of the preset off-axis distances through the following formula: Wherein, the An off-axis correction value corresponding to the preset off-axis distance; an off-axis radiation value corresponding to the preset off-axis distance; The average value of the sixth gray value of each target point corresponding to the preset off-axis distance is obtained; Correcting parameters for the dose; and determining an off-axis correction parameter through an interpolation algorithm according to the off-axis correction values respectively corresponding to the preset off-axis distances.
10. The method of calibrating a detector for use in radiation therapy according to claim 4, wherein said determining artifact correction parameters based on said artifact correction data comprises: For any one preset duration, after the detector is irradiated for the preset duration, according to a seventh gray value corresponding to the preset duration, determining an artifact prediction value according to the following formula: Wherein, the An artifact prediction value for a coordinate point (x, y); the average value of the seventh gray values of all coordinate points; the preset duration is the preset duration; The time length is the time length after the preset time length; 、、、 All are preset attenuation parameters; according to the artifact predicted value of each coordinate point and the eighth gray value, determining an artifact correction value corresponding to the preset duration through the following formula: Wherein, the For a preset time length of And stop the irradiation for a period of time of Artifact correction values of (a); for a preset time length of An eighth gray value of the time coordinate point (x, y); Artifact correction data is determined from each artifact correction value.
11. A detector calibration apparatus for radiation therapy, comprising: The acquisition unit is used for acquiring dark flat field reference data, bright flat field reference data, dose response data, radiation field correction data, die body correction data, off-axis correction data and artifact correction data; the dark flat field reference data comprises a dark flat field radiation value, a first gray value collected by each target point of a detector in a dark flat field, a bright flat field reference data comprises a bright flat field radiation value, a second gray value collected by each target point of the detector in a bright flat field, dose response data comprises a reference radiation value and a third gray value which are respectively obtained when the detector is in a plurality of preset reference radiation fields, the field correction data comprises a field radiation value and a fourth gray value which are respectively obtained when the detector corresponds to a plurality of preset field areas, the die body correction data comprises a die body radiation value and a fifth gray value which are respectively obtained when a plurality of die bodies with preset thickness are arranged between the detector and a transmitting source, and the off-axis correction data comprises an off-axis radiation value and a sixth gray value which are respectively obtained when the detector corresponds to a plurality of preset off-axis distances; and the calibration unit is used for determining calibration dosage values corresponding to different gray values of the detector respectively according to the dark flat field reference data, the bright flat field reference data, the dosage response data, the radiation field correction data, the die body correction data, the off-axis correction data and the artifact correction data.
12. A computer readable storage medium, characterized in that the storage medium stores a computer program which, when executed by a processor, implements the method of any of the preceding claims 1-10.
13. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of the preceding claims 1-10 when executing the program.
14. A computer program product, characterized in that instructions in the computer program product, when executed by a processor of an electronic device, cause the electronic device to perform the method of any of claims 1-10.

Description

Detector calibration method, device, medium and equipment applied to radiotherapy Technical Field The present disclosure relates to the field of medical equipment calibration technologies, and in particular, to a method, an apparatus, a medium, and a device for calibrating a detector applied to radiotherapy. Background Radiation therapy is a treatment for cancer. During treatment, it is necessary to irradiate cancer cells in the patient with ionizing radiation (e.g., X-rays, gamma rays, energetic electrons or heavy particles) to kill the cancer cells. Quality control and dose verification of therapeutic doses during radiation therapy are related to therapeutic efficacy and patient safety. An X-ray flat panel detector is an array type digital imaging device. The detector has the two-dimensional detection capability with large area and high resolution, excellent linearity, wide dynamic range and quick real-time reading capability, and therefore has the potential of being applied to radiotherapy dose verification. In the prior art, an X-ray flat panel detector is mainly oriented to medical diagnostic imaging, and a conversion relation exists between a readout value of the X-ray flat panel detector which is a gray value and a received radiation dose value. To achieve accurate dose measurement, the detector needs to be calibrated accurately by means of standard radiation fields and absolute dose measurement equipment (ionization chamber, etc.). However, in practical applications, factors such as pixel sensitivity, field size, thickness of the phantom, off-axis distance, and artifacts affect the accuracy of calibration. An accurate detector calibration scheme is lacking in the prior art. Disclosure of Invention The present specification provides a method, apparatus, medium and device for calibrating a detector for radiation therapy, to at least partially solve the above-mentioned problems of the prior art. The technical scheme adopted in the specification is as follows: The specification provides a method for calibrating a detector for radiation therapy, comprising: The method comprises the steps of acquiring dark flat field reference data, bright flat field reference data, dose response data, radiation field correction data, die body correction data, off-axis correction data and artifact correction data, wherein the dark flat field reference data comprises a dark flat field radiation value and a first gray value acquired by each target point of a detector in a dark flat field, the bright flat field reference data comprises a bright flat field radiation value and a second gray value acquired by each target point of the detector in a bright flat field, the dose response data comprises a reference radiation value and a third gray value which are respectively acquired when the detector is in a plurality of preset reference radiation fields, the radiation field correction data comprises a radiation field radiation value and a fourth gray value which are respectively acquired when the detector corresponds to a plurality of preset radiation field areas, and the die body correction data comprises a die body radiation value and a fifth gray value which are respectively acquired when a plurality of preset thickness die bodies are arranged between the detector and a transmitting source; And determining the calibration dosage values respectively corresponding to different gray scale values of the detector according to the dark flat field reference data, the bright flat field reference data, the dosage response data, the radiation field correction data, the die body correction data, the off-axis correction data and the artifact correction data. Preferably, the determining the calibration dose value corresponding to each of the different gray scale values of the detector according to the dark flat field reference data, the bright flat field reference data, the dose response data, the field correction data, the off-axis correction data of the phantom, and the artifact correction data includes: According to the dark flat field reference data and the bright flat field reference data, determining a corrected gray value according to the gray value acquired by any one target point; And determining a calibration dose value corresponding to different gray values of a target point in the detector according to the corrected gray value, the dose response data, the field correction data, the off-axis correction data of the die body and the artifact correction data. Preferably, the determining, according to the dark flat field reference data and the bright flat field reference data, the corrected gray value for the gray value collected by any one target point includes: According to the dark flat field reference data and the bright flat field reference data, aiming at the gray value acquired by any target point, determining a corrected gray value according to the following formula: Wherein, the Corrected gray values for the target points