Medical cyclotron beam flow intensity control method

Abstract

The invention relates to the technical field of cyclotrons, in particular to a medical cyclotron beam current intensity control method, which comprises the following steps: acquiring various beam current control parameter data of a medical cyclotron at each acquisition moment in real time; determining a stable deviation value of state response between any two kinds of beam control parameter data, and further determining a confidence difference value of various kinds of beam control parameter data; obtaining each time interval; determining response difference values of the various beam control parameter data in each time interval based on the confidence difference values and differences of discrete degrees between the various beam control parameter data in each time interval and all other beam control parameter data; and determining a deviation response value of the beam current intensity data at the current moment, and adjusting a feedback signal value at the current moment so as to control the beam current intensity in the medical cyclotron. The invention aims to improve the control precision of the beam current intensity of the medical cyclotron.

Description

Technical Field

[0001] This application relates to the technical field of cyclotrons, and particularly to a method for controlling the beam current intensity of a medical cyclotron. Background Art

[0002] As a large medical device in clinical practice, medical cyclotrons have been frequently used in clinical practice in recent years and are devices for producing medical radioisotopes. A medical cyclotron uses a magnetic field and an electric field to accelerate and cyclotron charged particles (such as protons, deuterons, etc.) to obtain sufficiently high energy, and then undergoes a nuclear reaction with a target substance to produce the required radioisotope. Because a medical cyclotron itself has relatively high performance requirements, the stability of the beam current is very important during the working state.

[0003] For a medical cyclotron, different application scenarios and radioisotope production requirements require beams with specific energies. For example, to produce certain radioisotopes used in Positron Emission Computed Tomography (PET), such as fluorine-18, the beam needs to have appropriate energy to undergo an effective nuclear reaction with the target substance. During the acceleration process of a medical cyclotron, it is necessary to maintain the stability of the beam current intensity to ensure that the accelerated particles do not diverge. However, in the actual control process, due to the influence of factors such as magnetic field strength and environmental factors, the stability of a series of parameters used to adjust and maintain the beam current stability in a medical cyclotron, such as magnetic field strength, radio frequency power, vacuum degree, etc., may shift, which may lead to beam instability and thus fail to meet the production requirements of radioisotopes. Moreover, the existing beam current intensity control methods ignore the problem of large detection errors of beam parameters caused by particle divergence during the actual detection process, resulting in relatively large control errors of the beam current intensity. Summary of the Invention

[0004] In view of the above, it is necessary to provide a method for controlling the beam current intensity of a medical cyclotron, which improves the control accuracy of the beam current intensity of the cyclotron compared with the traditional method for controlling the beam current intensity of a medical cyclotron.

[0005] A method for controlling the beam current intensity of a medical cyclotron in this application adopts the following technical solution: An embodiment of this application provides a method for controlling the beam current intensity of a medical cyclotron, and this method includes the following steps: Real-time collect various beam current control parameter data of the medical cyclotron at each acquisition moment, where there is beam current intensity data; Obtain the probability distribution curves of various beam control parameter data, and determine the stable deviation value of the state response between any two kinds of beam control parameter data based on the shape difference of the probability distribution curves between any two kinds of beam control parameter data; Determine the confidence difference values of various beam control parameter data based on the correlation between various beam control parameter data and all other kinds of beam control parameter data, as well as the stable deviation values therebetween; Based on the mutation situation of the beam current intensity data, divide the acquisition duration into each time interval, and determine the response difference values of various beam control parameter data in each time interval based on the confidence difference values and the difference in the degree of dispersion between various beam control parameter data and all other kinds of beam control parameter data in each time interval; Based on the distribution of the response difference values of the beam current intensity data in all time intervals, obtain the deviation response value of the beam current intensity data at the current moment; Adjust the feedback signal value at the current moment based on the deviation response value, and control the beam current intensity in the medical cyclotron based on the adjusted feedback signal value.

[0006] In one embodiment, the process of obtaining the probability distribution curve is: perform probability statistics on various beam control parameter data respectively, and obtain the probability distribution curves of various beam control parameter data according to the probability statistical results.

[0007] In one embodiment, the process of determining the stable deviation value is: Obtain the skewness coefficient and kurtosis coefficient of the probability distribution curve of each kind of beam control parameter data; Calculate the difference in the skewness coefficient and the difference in the kurtosis coefficient between any two kinds of beam control parameter data, which are respectively denoted as skewness difference and kurtosis difference; The stable deviation value is positively correlated with the skewness difference and the kurtosis difference respectively.

[0008] In one embodiment, the stable deviation value is the mean value of the skewness difference and the kurtosis difference.

[0009] In one embodiment, the expression of the confidence difference value is: ; where represents the confidence difference value of the th kind of beam control parameter data; represents the stable deviation value of the state response between the th kind and the th kind of beam control parameter data; represents the stable deviation value of the state response between the th kind and the The correlation coefficient between beam control parameter data; Denotes the exponential function with the natural constant as the base; Denotes the number of types of beam control parameters.

[0010] In one embodiment, the method for obtaining the time interval is as follows: Arrange all the collected beam current intensity data in chronological order to form a control parameter sequence, and divide the acquisition duration according to the moments where mutation points are located in the control parameter sequence to obtain each time interval.

[0011] In one embodiment, the determination process of the response difference value is as follows: Calculate the proportion of the confidence difference value of each type of beam control parameter data in the confidence difference values of all types of beam control parameter data; Record the difference in the degree of dispersion between any one type of beam control parameter data and the other types of beam control parameter data within each time interval as the dispersion difference; Statistically find the maximum value among the proportions of the above-mentioned any one type of beam control parameter data and the other types of beam control parameter data within each time interval; The response difference value of any one type of beam control parameter data within each time interval is positively correlated with the dispersion difference and negatively correlated with the maximum value.

[0012] In one embodiment, the expression of the response difference value is: ; where Denotes the response difference value of the th type of beam control parameter data within the th time interval; , respectively denote the degrees of dispersion of the th type and the th type of beam control parameter data within the th time interval; , respectively denote the proportions of the th type and the th type of beam control parameter data; Denotes the maximum value function; Denotes the number of types of beam control parameters.

[0013] In one embodiment, the deviation response value is the mean of the normalized values of the response difference values of the beam current intensity data within all time intervals.

[0014] In one embodiment, the expression for adjusting the feedback signal value at the current moment based on the deviation response value is: ; represents the adjusted feedback signal value at the current moment; represents the feedback signal value before adjustment at the current moment; represents the deviation response value of the beam current intensity data at the current moment; represents a preset value greater than 0.

[0015] This application has at least the following beneficial effects: In view of the problem that the existing method does not fully consider the relationship between the change of beam stability and the change of various beam control parameters during the actual use process, resulting in a large deviation of the feedback signal and affecting the control accuracy of the beam current intensity, based on the shape difference of the probability distribution curve between any two beam control parameter data, the stable deviation value of the state response between the any two beam control parameter data is determined; based on the correlation between various beam control parameter data and the remaining all beam control parameter data, and the stable deviation value therebetween, the confidence difference value of various beam control parameter data is determined; its beneficial effect lies in combining the stability difference and the correlation difference between various beam control parameter data during the actual use process of the medical cyclotron, and making a comparative analysis of the overall characteristic differences of different types of beam control parameter data changing with time, which is conducive to accurately extracting the correlation state characteristics between different types of beam control parameter data; Based on the mutation situation of the beam current intensity data, each time interval is obtained by dividing the acquisition duration. Based on the confidence difference value and the difference in the degree of dispersion between various beam control parameter data and the remaining all beam control parameter data within each time interval, the response difference value of various beam control parameter data within each time interval is determined; its beneficial effect lies in considering that different beam control parameters have different response characteristics to the beam stability deviation during the actual control process, combining the state correlation characteristics of different control parameters when the stability deviation occurs, and accurately highlighting the local influence characteristics of different control parameters for the stability deviation analysis through the confidence difference of the parameter changes of different beam control parameters within the same time period; Based on the distribution of the response difference values of the beam current intensity data in all time intervals, the deviation response value of the beam current intensity data at the current moment is obtained; its beneficial effect lies in analyzing a variety of beam control parameter data in a long time range, obtaining the possibility of differences in the response of the beam current intensity, being able to capture the possible anomalies in different time intervals, and thus providing a more accurate beam stability analysis result; Based on the deviation response value, the feedback signal value at the current moment is adjusted, and the beam current intensity in the medical cyclotron is controlled based on the adjusted feedback signal value; its beneficial effect lies in accurately adjusting the feedback signal based on the response deviation during the beam current intensity control process, and improving the control accuracy of the beam current intensity of the cyclotron. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a flowchart of the steps of a method for controlling the beam current intensity of a medical cyclotron provided by the present application; Figure 2 It is a schematic diagram of the determination process of the stable deviation value; Figure 3 It is a schematic diagram of the determination process of the response difference value. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary", "or", "for example" is intended to present relevant concepts in a specific manner.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. It should be understood that unless otherwise stated in this application, " / " means "or".

[0020] In addition, it should be noted that the terms "first" and "second" in this application are used to distinguish similar objects and are not used to describe a specific order or sequence.

[0021] The following will specifically describe the specific solution of a method for controlling the beam current intensity of a medical cyclotron provided by the present application with reference to the drawings.

[0022] A method for controlling the beam current intensity of a medical cyclotron provided by an embodiment of the present application. Specifically, a method for controlling the beam current intensity of a medical cyclotron is provided as follows. Please refer to Figure 1 and the method includes the following steps: Step 1: Real-time collect various beam control parameter data of the medical cyclotron at each acquisition moment, where there is beam current intensity data.

[0023] During the use of a medical cyclotron, the stability of the beam current intensity has a significant impact on the production of radioactive isotopes. If the beam current intensity is too low, it cannot meet the production requirements of radioactive isotopes; if the beam current intensity is too high, it may damage the equipment. Therefore, an appropriate beam current intensity is crucial for the efficient production of radioactive isotopes and the safe and stable operation of the medical cyclotron.

[0024] During the use of a medical cyclotron, various beam control parameter data are collected in real time, including beam energy data, beam current intensity data, magnetic field intensity data, radio frequency power data, and vacuum degree data. Among them, the beam energy data is a key parameter reflecting the energy carried by the beam. In different medical scenarios and different production requirements of radioactive isotopes, the medical cyclotron has different requirements for the energy carried by the beam. In this application, an energy detector is used to collect the beam energy data; a beam monitor is used to collect the beam current intensity data; the magnitude and stability of the magnetic field intensity directly affect the motion trajectory and acceleration effect of the beam. In this application, a magnetic resonance probe is used to collect the magnetic field intensity data to avoid interference with the magnetic field during the collection process; the radio frequency power data is obtained through a power sensor; the medical cyclotron needs to operate in a high-vacuum environment to reduce the collision between the beam and gas molecules and ensure the stability and transmission efficiency of the beam. In this application, a vacuum gauge is used to collect the vacuum degree data.

[0025] In this embodiment, during the process of collecting the beam control parameter data, the collection time interval is 10 minutes. The value of the collection time interval is preset manually, and the implementer can set it by himself / herself. This application does not make special restrictions.

[0026] Due to the influence factors of the device itself for collecting the beam control parameter data or environmental interference, the quality of the collected beam control parameter data may be poor. Therefore, filtering processing is performed on each type of beam control parameter data respectively.

[0027] In this embodiment, the median filtering method is used to perform filtering processing on the beam control parameter data. As other implementation manners, on the basis of being able to perform filtering processing on the beam control parameter data, the implementer can adopt other existing technologies, such as the mean filtering method, the Gaussian filtering method, etc. This application does not make special restrictions.

[0028] Step 2: Based on the change correlation characteristics between the beam control parameters during the use of the medical cyclotron, perform a confidence characteristic analysis on the stability deviation of the beam control parameters of the cyclotron, and obtain the deviation response value of the beam current intensity data based on the analysis result.

[0029] During the control process of a medical cyclotron, due to changes in the usage environment and parameter variations of the instruments used in conjunction with the medical cyclotron, stability deviations may occur in the beam control parameters of the medical cyclotron; for example, a medical cyclotron needs to operate in a high-vacuum environment. If the vacuum environment fluctuates, it may cause the beam to interact with gas molecules, leading to the divergence of particles. At the same time, changes in the magnetic field strength and radio frequency power during the acceleration process may affect the beam trajectory and acceleration effect; therefore, during the use of the cyclotron, for the stability analysis of the beam intensity of the cyclotron, it is necessary to combine the changes in various beam control parameters to obtain an accurate analysis result of the beam stability deviation.

[0030] Furthermore, based on the above analysis, in view of the differences in the stability characteristics during the control process of the medical cyclotron in different application scenarios, a comparative analysis is conducted on the stability of the beam current intensity during the actual use process.

[0031] Step 2.1, obtain the probability distribution curves of various beam control parameter data, and based on the shape differences between the probability distribution curves of any two beam control parameter data, determine the stable deviation value of the state response between the any two beam control parameter data.

[0032] Since during the use of a medical cyclotron, changes in its vacuum environment, magnetic field, and radio frequency power will affect the particle velocity, energy, and direction of the beam, when analyzing the stability of the beam current intensity in a medical cyclotron, it is necessary to comprehensively consider the correlation differences in data changes between different beam control parameters. During the actual use process, when different beam control parameters are affected by beam stability, the distribution of the parameters will vary; therefore, probability statistics are separately performed on various beam control parameter data, and curve fitting is separately performed on the probability statistical results. The obtained fitting curves are used as the probability distribution curves of various beam control parameter data. The probability distribution curves represent the distribution of each beam control parameter during the use of the medical cyclotron, that is, under normal circumstances, the distribution of each beam control parameter of the medical cyclotron should be a concentrated distribution, specifically manifested as a single-peak or sharp-peak state.

[0033] In this embodiment, the least squares method is used to perform curve fitting on the probability statistical results. As other implementation manners, on the basis of being able to perform curve fitting on the probability statistical results, the implementer can use other existing technologies for curve fitting, such as locally weighted regression, K-nearest neighbor regression, etc. This application does not make special restrictions.

[0034] Further, during the use of a medical cyclotron, if there is a deviation in the beam current intensity stability, the deviation in the beam current intensity stability will affect the distribution states of multiple beam control parameters, including the environment, magnetic field intensity, and power, that is, there are differences in the responses of the vacuum degree, magnetic field intensity, and power to the stability deviation, resulting in relatively large differences in the peak states of the distributions of different beam control parameters, and there are difference characteristics in the peak shape and peak shift changes; therefore, obtain the skewness coefficient and kurtosis coefficient of the probability distribution curve of each beam control parameter data; calculate the difference in the skewness coefficient and the difference in the kurtosis coefficient between any two beam control parameter data, which are respectively denoted as the skewness difference and the kurtosis difference, and take the mean of the skewness difference and the kurtosis difference between the any two beam control parameter data as the stable deviation value of the state response between the any two beam control parameter data; the larger the stable deviation value, the greater the distribution difference between the any two beam control parameter data during the operation of the medical cyclotron; further, calculate the correlation coefficient between any two beam control parameter data, and the larger the correlation coefficient, the more significant the overall correlation characteristics of these two beam control parameter data changing with time. Among them, the calculation processes of the skewness coefficient and kurtosis coefficient of the probability distribution curve are well-known technologies and will not be elaborated in this application. The schematic diagram of the determination process of the stable deviation value is as Figure 2 shown.

[0035] In this embodiment, during the calculation of the stable deviation value, all the involved differences are absolute values of differences. As other implementation manners, on the basis of being able to measure the differences between skewness coefficients and the differences between kurtosis coefficients, implementers can use other calculation methods for measurement, such as ratios, squares of differences, etc., and this application does not make special restrictions.

[0036] In this embodiment, the correlation coefficient between two beam control parameter data is the Pearson correlation coefficient. As other implementation manners, on the basis of being able to measure the correlation between two beam control parameter data, implementers can use other existing technologies for measurement, such as the Spearman correlation coefficient, Kendall rank correlation coefficient, etc., and this application does not make special restrictions.

[0037] Step 2.2, based on the correlations between various beam control parameter data and all the other types of beam control parameter data, and the stable deviation values therebetween, determine the confidence difference values of various beam control parameter data.

[0038] The expression of the confidence difference values of various beam control parameter data is: ; in the formula, represents the confidence difference value of the th type of beam control parameter data; represents the The stable deviation value of the state response between the th and the th beam control parameter data; The correlation coefficient between the th and the th beam control parameter data; An exponential function with the natural constant as the base, aiming to avoid a denominator of 0;

[0039] It should be noted that: the larger the calculated confidence difference value, the greater the difference in the stability characteristics between the th beam control parameter data and the remaining beam control parameter data during the analysis of the parameter characteristics in the operation of the medical cyclotron, and the greater the difference in the associated distribution of the overall parameter changes between them.

[0040] Step 2.3: Based on the mutation situation of the beam current intensity data, divide the acquisition duration to obtain each time interval. Based on the confidence difference value and the difference in the degree of dispersion between each beam control parameter data and the remaining all beam control parameter data within each time interval, determine the response difference value of each beam control parameter data within each time interval.

[0041] Through the above analysis, the overall characteristic differences in the variation of different beam control parameter data over time during the operation of the medical cyclotron are compared and analyzed. The purpose is to combine the direct or indirect influence relationships between the correlation differences and the state characteristic differences among the environment, magnetic field, power, energy, and beam intensity due to the beam stability change during the operation of the medical cyclotron, accurately extract the associated state characteristics between different beam control parameter data, and then accurately analyze the influence of different beam control parameters on the deviation of beam stability during the beam control process.

[0042] During the use of a medical cyclotron, if the stability of the beam deviates in a short period of time, it may be that the disturbance of parameters such as the environment, magnetic field, and power leads to a decrease in beam stability, and it is impossible to ensure that the beam particles are stably accelerated along the trajectory under the set current intensity. Therefore, considering that the response characteristics of different beam control parameters to beam stability deviations are different in the actual control process, combined with the state correlation characteristics of different control parameters when stability deviations occur, when performing stability characteristic analysis between different beam control parameters, the confidence differences of parameter changes of different beam control parameters in the same time period are used to accurately highlight the local influence characteristics of different control parameters during stability deviation analysis; therefore, for the control process of a medical cyclotron, the proportion of the confidence difference values ​​of various beam control parameter data in the confidence difference values ​​of all beam control parameter data is calculated, with the aim of quantifying the comparative differences between different beam control parameters and highlighting the local comparative characteristics between different beam control parameters.

[0043] Furthermore, during the use of the medical cyclotron, the influences of different control parameters appear successively, that is, changes in vacuum degree, magnetic field and power within a local time range will cause beam particles to diverge, thereby leading to continuous instantaneous changes in energy and flux in a short period of time; therefore, all the collected beam flux data are arranged in time series to form a control parameter sequence, and a mutation point detection algorithm is used to obtain the mutation point in the control parameter sequence, and the acquisition time is divided according to the time of the mutation point to obtain each time interval.

[0044] In this embodiment, the Pettitt mutation point detection algorithm is used to obtain the mutation points in the control parameter sequence. As other implementation methods, on the basis of being able to obtain the mutation points in the control parameter sequence, the implementer can use other existing technologies to obtain the mutation points in the control parameter sequence, such as the Bayesian mutation point detection algorithm, the Mann-Kendall mutation point detection algorithm, etc., and this application does not make any special restrictions.

[0045] In this embodiment, the time interval is divided as follows: for example, the time at which the mutation point in the control parameter sequence is located is , , , , , then the time interval is divided into .

[0046] Furthermore, in order to accurately analyze the correlation differences in the stability changes of beam control parameters during the actual operation of the medical cyclotron, the discrete degree of the data of each beam control parameter in each time interval was calculated to reflect the local stability characteristics of each beam control parameter during the control process of the medical cyclotron.

[0047] In this embodiment, the degree of dispersion is the coefficient of variation. As other implementation manners, based on the basis of being able to measure the degree of uneven distribution of each kind of beam control parameter data within each time interval, the implementer can use other existing technologies for measurement, such as variance, standard deviation, etc., and this application does not make special restrictions.

[0048] Based on the confidence difference value and the difference in the degree of dispersion between each kind of beam control parameter data and all the other kinds of beam control parameter data within each time interval, determine the response difference value of each kind of beam control parameter data within each time interval. The expression is: ; In the formula, represents the response difference value of the th kind of beam control parameter data within the th time interval; , respectively represent the degrees of dispersion of the th and the th kinds of beam control parameter data within the th time interval; , respectively represent the proportions of the th and the th kinds of beam control parameter data; represents the maximum value function; represents the number of types of beam control parameters.

[0049] It should be noted that: the larger the calculated response difference value is, it indicates that during the operation of the medical cyclotron, through the comparison of local stability characteristics, the characteristics of the local correlation influence of the th kind of beam control parameter are more significant. The schematic diagram of the determination process of the response difference value is as Figure 3 shown.

[0050] Step 2.4, based on the distribution of the response difference values of the beam current intensity data within all time intervals, obtain the deviation response value of the beam current intensity data at the current moment.

[0051] During the use of the medical cyclotron, in combination with the analysis result of the characteristics of the local correlation influence of the beam current intensity data up to the current moment, accurately analyze the response deviation during the beam current intensity control process. Specifically, take the mean value of the normalized values of the response difference values of the beam current intensity data within all time intervals as the deviation response value of the beam current intensity data at the current moment.

[0052] In this embodiment, the Z-Score normalization method is used to normalize the response difference value. As other implementation manners, on the basis of being able to normalize the response difference value, implementers can use other existing technologies to normalize the response difference value, such as the Min-Max normalization method, the decimal scaling normalization method, etc. This application does not make special restrictions.

[0053] It should be noted that: the larger the deviation response value is, the greater the possibility that the response of the beam current intensity is different due to the influence of environmental changes and related parameter changes during the operation of the medical cyclotron; the smaller the deviation response value is, the smaller the possibility that the response of the beam current intensity is different due to the influence of environmental changes and related parameter changes during the operation of the medical cyclotron.

[0054] Step 3, adjust the feedback signal value at the current moment based on the deviation response value, and control the beam current intensity in the medical cyclotron based on the adjusted feedback signal value.

[0055] In the process of realizing the control of the beam current intensity, if the response changes of the beam current intensity have large differences in combination with the change characteristics analysis of different control parameters, the beam current intensity error should also be relatively large in the actual feedback adjustment process; therefore, based on the deviation response value of the beam current intensity data at the current moment, adjust the deviation of the currently feedback beam current intensity; the specific adjustment relationship formula is: ; represents the adjusted feedback signal value at the current moment; represents the feedback signal value before adjustment at the current moment; represents the deviation response value of the beam current intensity data at the current moment; represents a preset value greater than 0, and the purpose is to avoid the adjusted feedback signal value being too small. The value of is preset manually, and implementers can set it by themselves. In this embodiment, the value of is 0.5.

[0056] Based on the adjusted feedback signal value at the current moment, use a PID controller to perform feedback control on the beam current intensity in the medical cyclotron. The specific parameters of the PID controller can be determined by the attenuation curve method. The specific usage method of the PID controller is well known to those skilled in the art, and this application will not elaborate.

[0057] In summary, in view of the problem that the existing method does not fully consider the relationship between the change of beam current stability and the change of various beam current control parameters during the actual use process, resulting in a large deviation of the feedback signal and affecting the control accuracy of the beam current intensity, based on the shape difference of the probability distribution curve between any two beam current control parameter data, the stable deviation value of the state response between the any two beam current control parameter data is determined; based on the correlation between various beam current control parameter data and all the other beam current control parameter data, and the stable deviation value therebetween, the confidence difference value of various beam current control parameter data is determined; the beneficial effect lies in that by combining the stability difference and the correlation difference between various beam current control parameter data during the actual use process of the medical cyclotron, the overall characteristic difference of the change of different types of beam current control parameter data over time is compared and analyzed, which is conducive to accurately extracting the correlation state characteristics between different types of beam current control parameter data. Further, based on the mutation situation of the beam current intensity data, each time interval is divided for the acquisition duration. Based on the confidence difference value and the difference in the degree of dispersion between various beam current control parameter data and all the other beam current control parameter data within each time interval, the response difference value of various beam current control parameter data within each time interval is determined; the beneficial effect lies in that considering that different beam current control parameters have different response characteristics to the beam current stability deviation during the actual control process, combining the state correlation characteristics of different control parameters when the stability deviation occurs, and through the confidence difference of the parameter changes of different beam current control parameters within the same time period, the local influence characteristics of different control parameters for the stability deviation analysis are accurately highlighted. Further, based on the distribution situation of the response difference values of the beam current intensity data in all time intervals, the deviation response value of the beam current intensity data at the current moment is obtained; the beneficial effect lies in that by analyzing a variety of beam current control parameter data in a long time range, the possibility of the response of the beam current intensity to appear different is obtained, and the anomalies that may occur in different time intervals can be captured, so as to provide a more accurate beam current stability analysis result. Further, based on the deviation response value, the feedback signal value at the current moment is adjusted, and the beam current intensity in the medical cyclotron is controlled based on the adjusted feedback signal value; the beneficial effect lies in that based on the response deviation during the beam current intensity control process, the feedback signal is accurately adjusted, and the control accuracy of the beam current intensity of the cyclotron is improved.

[0058] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of code, or a part thereof that contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the blocks may occur in a different order than noted in the accompanying drawings. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. In the description corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0059] For those skilled in the art, it is obvious that the present application is not limited to the details of the above-described exemplary embodiments, and without departing from the basic characteristics of the present application, the present application can be implemented in other specific forms. Therefore, from any point of view, the above-described embodiments of the present application should be regarded as exemplary and non-limiting.

Claims

1. A method for controlling the beam current intensity of a medical cyclotron, characterized in that, The method includes the following steps: Collect various beam control parameter data of the medical cyclotron in real time at each acquisition moment, where there is beam current intensity data; Obtain the probability distribution curves of various beam control parameter data, and determine the stable deviation value of the state response between any two beam control parameter data based on the shape difference of the probability distribution curves between any two beam control parameter data; Determine the confidence difference value of various beam control parameter data based on the correlation between various beam control parameter data and all other types of beam control parameter data, and the stable deviation value therebetween; Based on the mutation situation of the beam current intensity data, divide the acquisition duration to obtain each time interval, and determine the response difference value of various beam control parameter data in each time interval based on the confidence difference value and the difference in the degree of dispersion between various beam control parameter data and all other types of beam control parameter data in each time interval; Based on the distribution of the response difference values of the beam current intensity data in all time intervals, obtain the deviation response value of the beam current intensity data at the current moment; Adjust the feedback signal value at the current moment based on the deviation response value, and control the beam current intensity in the medical cyclotron based on the adjusted feedback signal value.

2. The beam current intensity control method of a medical cyclotron according to claim 1, characterized in that, The process of obtaining the probability distribution curve is as follows: perform probability statistics on various beam control parameter data respectively, and obtain the probability distribution curves of various beam control parameter data according to the probability statistical results.

3. The beam intensity control method of a medical cyclotron according to claim 1, characterized in that The process of determining the stable deviation value is as follows: Obtain the skewness coefficient and kurtosis coefficient of the probability distribution curve of each beam control parameter data; Calculate the difference in the skewness coefficient and the difference in the kurtosis coefficient between any two beam control parameter data, and record them as skewness difference and kurtosis difference respectively; The stable deviation value is positively correlated with the skewness difference and the kurtosis difference respectively.

4. The beam current intensity control method of a medical cyclotron according to claim 3, characterized in that, The stable deviation value is the mean of the skewness difference and the kurtosis difference.

5. A beam current intensity control method for a medical cyclotron according to claim 1, characterized in that, The expression of the confidence difference value is: ; wherein, represents the confidence difference value of the th beam current control parameter data; represents the stable deviation value of the state response between the th and the th beam current control parameter data; represents the correlation coefficient between the th and the th beam current control parameter data; represents the exponential function with the natural constant as the base; represents the number of types of beam current control parameters.

6. The beam current intensity control method of a medical cyclotron according to claim 1, wherein The method of obtaining the time interval is as follows: arrange all the collected beam current intensity data in time sequence to form a control parameter sequence, and divide the acquisition duration according to the moments where the mutation points are located in the control parameter sequence to obtain each time interval.

7. A method for controlling the beam current intensity of a medical cyclotron according to claim 1, characterized in that, The process of determining the response difference value is as follows: Calculate the proportion of the confidence difference value of various beam control parameter data in the confidence difference values of all types of beam control parameter data; Record the difference in the degree of dispersion between any one beam control parameter data and all other types of beam control parameter data in each time interval as the dispersion difference; Statistical maximum value of the proportion in each time interval between any one beam control parameter data and all other types of beam control parameter data; The response difference value of any one beam control parameter data in each time interval is positively correlated with the dispersion difference and negatively correlated with the maximum value.

8. The method for controlling beam current intensity of a medical cyclotron according to claim 7, characterized in that, The expression of the response difference value is: ; wherein, represents the response difference value of the th beam current control parameter data in the th time interval; and respectively represent the dispersion degrees of the th and th beam current control parameter data in the th time interval; and respectively represent the said proportions of the th and th beam current control parameter data; represents the maximum value function; represents the number of types of beam current control parameters.

9. The beam current intensity control method of a medical cyclotron according to claim 1, characterized in that The deviation response value is the mean of the normalized values of the response difference values of the beam current intensity data in all time intervals.

10. A beam current intensity control method for a medical cyclotron according to claim 1, characterized in that, The expression of adjusting the feedback signal value at the current moment based on the deviation response value is: ; represents the adjusted feedback signal value at the current moment; represents the feedback signal value before adjustment at the current moment; represents the deviation response value of the beam current intensity data at the current moment; represents a preset value greater than 0.

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