CN-120242345-B - Zero-finding device, method and equipment for MLC (MLC) leaf encoder and storage medium

CN120242345BCN 120242345 BCN120242345 BCN 120242345BCN-120242345-B

Abstract

The application provides a zero-finding device, method and equipment for an MLC blade encoder and a storage medium, and relates to the technical field of medical equipment. The zero-searching device of the MLC leaf encoder effectively solves the problem of reference point error caused by damage of a light source and a photoelectric element in a high-radiation environment by dynamically adjusting the zero-searching threshold value. The device can automatically adapt to environmental changes, ensures accurate setting of the reference position after each power-on, and remarkably improves the accuracy and reliability of blade position control.

Inventors

GONG CHAO
LI JUNFENG
TIAN LIANG
XU ZHIJIAN

Assignees

中核粒子医疗科技有限公司

Dates

Publication Date: 20260508
Application Date: 20250425

Claims (7)

1. An MLC leaf encoder zero-finding device, the device comprising: a light source for generating light; a photodiode for receiving light generated by the light source and converting an optical signal into an electrical signal; the signal processing circuit is used for converting the electric signal generated by the photodiode under the non-shielding condition into a digital signal and determining a zero searching threshold value according to the digital signal; The comparator is used for comparing the intensity of the optical signal received by the photodiode under the shielding condition with the zero searching threshold value, and outputting a trigger signal when the intensity of the optical signal received under the shielding condition is equal to the zero searching threshold value; a relative encoder for setting a reference value according to a trigger signal of the comparator; A control circuit for controlling movement of the MLC leaves and receiving signals of the relative encoder; The signal processing circuit comprises a current-voltage conversion circuit, an analog-to-digital conversion circuit, a controller and a digital-to-analog conversion circuit, wherein the current-voltage conversion circuit is used for converting an electric signal generated by the photodiode under the condition of no shielding into a first voltage signal, the analog-to-digital conversion circuit is used for digitizing the first voltage signal, and the controller is used for controlling the digital-to-analog conversion circuit to output a threshold voltage according to the digitized first voltage signal, and the threshold voltage is used as the zero-finding threshold value; the outputting the threshold voltage according to the digitized first voltage signal includes: And calculating a threshold voltage V 0 ,V 1 as the first voltage signal by using a formula V 0 =A×V 1 +B, wherein A, B is a preset fixed coefficient.
2. The apparatus of claim 1, wherein the apparatus further comprises: And the collimator is arranged at the transmitting end and the receiving end and is used for reducing the influence of scattered light on position detection.
3. The device of claim 1, wherein the light source is an infrared light source.
4. The apparatus of claim 1, further comprising a narrow band light filter disposed between the photodiode and the light source for reducing the effect of ambient light on light detection.
5. A method of MLC leaf encoder zero-finding, the method comprising: Measuring an optical signal of the light source to the photodiode under an unobstructed condition before performing the reference position detection; determining a zero-finding threshold according to the light signal intensity of the light source to the photodiode under the non-shielding condition; driving a single MLC leaf to move towards a detection light path between the light source and the photodiode; When the intensity of the optical signal received by the photodiode is equal to the zero-finding threshold value, setting the current moment position of the encoder of the MLC blade as a reference value; The method for determining the zero-seeking threshold value according to the light signal intensity of the light source to the photodiode under the non-shielding condition comprises the steps of converting an electric signal generated by the photodiode under the non-shielding condition into a first voltage signal through a current-voltage conversion circuit, digitizing the first voltage signal through an analog-to-digital conversion circuit, and controlling the digital-to-analog conversion circuit to output a threshold voltage according to the digitized first voltage signal through a controller, wherein the threshold voltage is used as the zero-seeking threshold value; And calculating a threshold voltage V 0 by using a formula V 0 =A×V 1 +B, wherein V 1 is the first voltage signal, and A, B is a preset fixed coefficient.
6. A computing device, wherein the computing device comprises a memory, a processor; The memory is used for storing a computer program; the processor being configured to implement the method of claim 5 when executing the computer program.
7. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program which, when executed by a processor, implements the method according to claim 5.

Description

Zero-finding device, method and equipment for MLC (MLC) leaf encoder and storage medium Technical Field The application relates to the technical field of medical equipment, in particular to a zero-finding device, method, equipment and storage medium of an MLC blade encoder. Background In the medical field, multi-leaf collimators (multi-leaf collimator, MLC) are widely used in conformal radiation therapy as a key mechanical moving part. The position of the blade is accurately controlled, so that a radiation field matched with the shape of the lesion can be generated, and the accuracy and the effect of radiotherapy are improved. However, in order to achieve accurate control of the blade position, accurate detection of its position is required. In existing applications, a fixed threshold is typically used to determine the reference position, which can yield acceptable results in a non-radiative environment. However, in medical accelerator systems, the MLC is in a high-radiation environment, which presents special challenges to its position detection system. Specifically, radiation may cause damage to the light source device, thereby reducing luminous efficiency and weakening output light intensity. At the same time, the radiation also causes a reduction in the photoelectric conversion efficiency, so that the output signal is reduced. If the threshold is not adjusted accordingly in this case, the position of the vane when the threshold is reached may shift, resulting in a fiducial error. Such errors can directly affect the accuracy of the MLC leaf position, and thus the effectiveness and safety of the radiation treatment. Disclosure of Invention In view of the above problems, the present application provides a zero-finding device for an MLC leaf encoder, which comprises the following components: in a first aspect, the present application provides an MLC leaf encoder zero-finding device, the device comprising: a light source for generating light; a photodiode for receiving light generated by the light source and converting an optical signal into an electrical signal; the signal processing circuit is used for converting the electric signal generated by the photodiode under the non-shielding condition into a digital signal and determining a zero searching threshold value according to the digital signal; The comparator is used for comparing the intensity of the optical signal received by the photodiode under the shielding condition with the zero searching threshold value, and outputting a trigger signal when the intensity of the optical signal received under the shielding condition is equal to the zero searching threshold value; a relative encoder for setting a reference value according to a trigger signal of the comparator; and the control circuit is used for controlling the movement of the MLC blade and receiving signals of the relative encoder. Optionally, the signal processing circuit includes a current-to-voltage conversion circuit, an analog-to-digital conversion circuit, a controller and a digital-to-analog conversion circuit, where the current-to-voltage conversion circuit is configured to convert an electrical signal generated by the photodiode under a non-shielding condition into a first voltage signal, the analog-to-digital conversion circuit is configured to digitize the first voltage signal, and the controller is configured to control the digital-to-analog conversion circuit to output a threshold voltage according to the digitized first voltage signal, and take the threshold voltage as the zero-seeking threshold. Optionally, the outputting the threshold voltage according to the digitized first voltage signal includes: And calculating a threshold voltage V 0,V1 as the first voltage signal by using a formula V 0＝A×V1 +B, wherein A, B is a preset fixed coefficient. Optionally, the apparatus further includes: And the collimator is arranged at the transmitting end and the receiving end and is used for reducing the influence of scattered light on position detection. Optionally, the light source is an infrared light source. Optionally, the device further comprises a narrow-band light filter, disposed between the photodiode and the light source, for reducing the influence of ambient light on light detection. In a second aspect, the present application provides a method for zeroing an MLC leaf encoder, the method comprising: Measuring an optical signal of the light source to the photodiode under an unobstructed condition before performing the reference position detection; determining a zero-finding threshold according to the light signal intensity of the light source to the photodiode under the non-shielding condition; driving a single MLC leaf to move towards a detection light path between the light source and the photodiode; When the intensity of the optical signal received by the photodiode is equal to the zero-seeking threshold value, the current moment position of the encoder of the MLC blade is set as a r