A method for controlling beam intensity of medical cyclotron

Abstract

The present application relates to the field of cyclotron technology, and specifically to a method for controlling beam intensity of a medical cyclotron. The method comprises: real-time acquisition of multiple beam control parameter data of the medical cyclotron at each acquisition moment; determining a stable deviation value of a state response between any two beam control parameter data, and thereby determining a confidence difference value for each beam control parameter data; acquiring each time interval; determining a response difference value for each beam control parameter data within each time interval based on the confidence difference value and the difference in the degree of dispersion between each beam control parameter data and all other beam control parameter data within each time interval; determining a deviation response value of the beam intensity data at the current moment, and adjusting the feedback signal value at the current moment to control the beam intensity in the medical cyclotron. The present application aims to improve the control accuracy of the beam intensity of the medical cyclotron.

Description

Technical Field

[0001] The present application relates to the technical field of cyclotron accelerators, and in particular to a method for controlling the beam current intensity of a medical cyclotron accelerator. Background Art

[0002] Medical cyclotrons, large-scale medical devices used in clinical practice, have seen increasing frequency of use in recent years. They are used to produce medical radioisotopes. Medical cyclotrons utilize magnetic and electric fields to accelerate and swirl charged particles (such as protons and deuterons), achieving sufficiently high energies. These particles then react with target materials to produce the desired radioisotopes. Because medical cyclotrons inherently have high performance requirements, beam stability during operation is crucial.

[0003] For medical cyclotrons, different application scenarios and radioisotope production requirements require beams of specific energies. For example, the production of certain radioisotopes used in positron emission computed tomography (PET), such as fluorine-18, requires a beam with appropriate energy to undergo an effective nuclear reaction with the target material. During the acceleration process of a medical cyclotron, the stability of the beam intensity must be maintained to ensure that the accelerated particles do not diverge. However, in the actual control process, due to the influence of magnetic field strength and environmental factors, the stability of a series of parameters used to adjust and maintain beam stability in the medical cyclotron, such as magnetic field strength, radio frequency power, and vacuum degree, may shift. This may cause the beam to be unstable and thus fail to meet the production requirements of radioisotopes. Existing beam intensity control methods ignore the problem of large beam parameter detection errors caused by particle divergence during the actual detection process, resulting in still large errors in beam intensity control. Summary of the Invention

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

[0005] A medical cyclotron beam intensity control method of the present application adopts the following technical solution:

[0006] One embodiment of the present application provides a method for controlling the beam intensity of a medical cyclotron, the method comprising the following steps:

[0007] Real-time acquisition of various beam control parameter data of medical cyclotron at each acquisition moment, including beam intensity data;

[0008] Obtaining probability distribution curves of various beam control parameter data, and determining a stable deviation value of a state response between any two beam control parameter data based on a shape difference of the probability distribution curves between the any two beam control parameter data;

[0009] determining confidence difference values of the various beam control parameter data based on correlations between the various beam control parameter data and all other beam control parameter data, and the stable deviation values therebetween;

[0010] Based on the sudden change of the beam current intensity data, the acquisition time is divided into various time intervals, and based on the confidence difference value and the difference in the degree of dispersion between the various beam control parameter data in each time interval and all other beam control parameter data, the response difference value of the various beam control parameter data in each time interval is determined;

[0011] Based on the distribution of the response difference values of the beam intensity data in all time intervals, the deviation response value of the beam intensity data at the current moment is obtained;

[0012] The feedback signal value at the current moment is adjusted based on the deviation response value, and the beam current intensity in the medical cyclotron is controlled based on the adjusted feedback signal value.

[0013] In one embodiment, the process of acquiring the probability distribution curve is: performing probability statistics on various beam control parameter data respectively, and obtaining the probability distribution curves of the various beam control parameter data according to the probability statistics results.

[0014] In one embodiment, the process of determining the stable deviation value is as follows:

[0015] Obtain the skewness coefficient and kurtosis coefficient of the probability distribution curve of each beam control parameter data;

[0016] Calculating the difference in skewness coefficient and kurtosis coefficient between any two beam control parameter data, which are recorded as skewness difference and kurtosis difference respectively;

[0017] The stable deviation value is positively correlated with the skewness difference and the kurtosis difference, respectively.

[0018] In one embodiment, the stable deviation value is the mean of the skewness difference and the kurtosis difference.

[0019] In one embodiment, the expression of the confidence difference value is:

[0020] Where, Indicates the Confidence difference value of the beam control parameter data; Indicates the Species and The stable deviation value of the state response between the beam control parameter data; Indicates the Kind and The correlation coefficient between the beam control parameter data; represents an exponential function with a natural constant as its base; Indicates the number of types of beam control parameters.

[0021] In one embodiment, the method for obtaining the time interval is: arranging all the collected beam current intensity data in time sequence to form a control parameter sequence, and dividing the collection time according to the time of the mutation point in the control parameter sequence to obtain each time interval.

[0022] In one embodiment, the response difference value is determined as follows:

[0023] Calculate the proportion of the confidence difference values of various beam control parameter data in the confidence difference values of all beam control parameter data;

[0024] The difference in the degree of dispersion between any beam control parameter data and the other beam control parameter data in each time interval is recorded as the dispersion difference;

[0025] Counting the maximum value of the proportions of any one beam control parameter data to other beam control parameter data in each time interval;

[0026] The response difference value of any one type of beam control parameter data in each time interval is positively correlated with the discrete difference and negatively correlated with the maximum value.

[0027] In one embodiment, the expression of the response difference value is:

[0028] Where, Indicates the The beam control parameter data is The response difference value within the time interval; 、 Respectively represent In the time interval Type, The discrete degree of the beam control parameter data; 、 Respectively represent Type, The proportion of the beam control parameter data; represents the maximum value function; Indicates the number of types of beam control parameters.

[0029] In one embodiment, the deviation response value is the average of normalized values of response difference values of the beam current intensity data in all time intervals.

[0030] In one embodiment, the expression for adjusting the feedback signal value at the current moment based on the deviation response value is:

[0031] ; Indicates the adjusted feedback signal value at the current moment; Indicates the feedback signal value before adjustment at the current moment; Indicates the deviation response value of the beam current intensity data at the current moment; Indicates a preset value greater than 0.

[0032] This application has at least the following beneficial effects:

[0033] The present application addresses the problem that existing methods do not fully consider the relationship between changes in beam stability and changes in various beam control parameters during actual use, resulting in large deviations in feedback signals and affecting the control accuracy of beam 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 all other types of beam control parameter data, and the stable deviation values between them, the confidence difference value of the various beam control parameter data is determined; the application has the beneficial effect of combining the stability differences and correlation differences between various beam control parameter data during actual use of a medical cyclotron to compare and analyze the overall characteristic differences of different types of beam control parameter data over time, which is conducive to accurately extracting the correlation state characteristics between different types of beam control parameter data;

[0034] Based on the sudden change of beam intensity data, the acquisition time is divided into time intervals. Based on the confidence difference value and the difference in the degree of dispersion between the various beam control parameter data and all other beam control parameter data in each time interval, the response difference value of the various beam control parameter data in each time interval is determined. The beneficial effect is that the response characteristics of different beam control parameters to beam stability deviations in the actual control process are different. In combination with the state correlation characteristics of different control parameters when stability deviations occur, the confidence difference of the parameter changes of different beam control parameters in the same time period is used to accurately highlight the local influence characteristics of different control parameters on stability deviation analysis.

[0035] Based on the distribution of response differences in beam intensity data across all time intervals, the deviation response value of the beam intensity data at the current moment is obtained. This has the beneficial effect of analyzing multiple beam control parameter data over a long period of time to determine the likelihood of differences in beam intensity responses. This allows for the capture of anomalies that may occur in different time intervals, thereby providing more accurate beam stability analysis results.

[0036] The feedback signal value at the current moment is adjusted based on the deviation response value, and the beam intensity in the medical cyclotron is controlled based on the adjusted feedback signal value; its beneficial effect is that the feedback signal is accurately adjusted based on the response deviation in the beam intensity control process, thereby improving the control accuracy of the beam intensity of the cyclotron. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 A flowchart of the steps of a medical cyclotron beam intensity control method provided in this application;

[0039] Figure 2 Schematic diagram of the process for determining the stable deviation value;

[0040] Figure 3 Schematic diagram of the process for determining the response difference value. DETAILED DESCRIPTION

[0041] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present the relevant concepts in a concrete manner.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application relates. The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be understood that, unless otherwise indicated, " / " represents or.

[0043] It should also be noted that the terms "first" and "second" in this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0044] The following describes in detail a specific scheme of a medical cyclotron beam intensity control method provided by the present application with reference to the accompanying drawings.

[0045] An embodiment of the present application provides a method for controlling the beam current intensity of a medical cyclotron accelerator. Specifically, the following method for controlling the beam current intensity of a medical cyclotron accelerator is provided. Figure 1 , the method comprises the following steps:

[0046] Step 1: Real-time acquisition of various beam control parameter data of a medical cyclotron at each acquisition moment, including beam intensity data.

[0047] During the use of medical cyclotrons, the stability of the beam current has a significant impact on the production of radioactive isotopes. If the beam current is too low, it cannot meet the production needs of radioactive isotopes; if the beam current is too high, it may damage the equipment. Therefore, appropriate beam current is crucial for the efficient production of radioactive isotopes and the safe and stable operation of medical cyclotrons.

[0048] During the use of the medical cyclotron, a variety of beam control parameter data are collected in real time, including beam energy data, beam current intensity data, magnetic field strength data, radio frequency power data and vacuum degree data. Among them, beam energy data is a key parameter reflecting the energy carried by the beam. The medical cyclotron has different requirements for beam energy in different medical scenarios and different radioisotope production needs. In this application, an energy detector is used to collect beam energy data; a beam monitor is used to collect beam current intensity data; the magnitude and stability of the magnetic field strength directly affect the motion trajectory and acceleration effect of the beam. In this application, a magnetic resonance probe is used to collect magnetic field strength data to avoid interference with the magnetic field during the collection process; radio frequency power data is obtained through a power sensor; the medical cyclotron needs to operate in a high vacuum environment to reduce collisions between the beam and gas molecules and ensure beam stability and transmission efficiency. In this application, a vacuum gauge is used to collect vacuum degree data.

[0049] In this embodiment, during the process of collecting beam control parameter data, the collection time interval is 10 minutes. The value of the collection time interval is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0050] Due to the influence of the device itself or environmental interference for collecting beam control parameter data, 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.

[0051] In this embodiment, the median filtering method is used to filter the beam control parameter data. As other implementation methods, on the basis of being able to filter the beam control parameter data, the implementer can adopt other existing technologies, such as the mean filtering method, the Gaussian filtering method, etc., and this application does not impose any special restrictions.

[0052] Step 2: Based on the correlation characteristics of the changes between the beam control parameters during the use of the medical cyclotron, the confidence characteristic analysis of the stability deviation of the beam control parameters of the cyclotron is performed, and the deviation response value of the beam current intensity data is obtained based on the analysis results.

[0053] During the control process of a medical cyclotron, changes in the operating environment and parameters of the instruments used in conjunction with the medical cyclotron may cause stability deviations 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, triggering particle divergence. At the same time, changes in 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, the stability analysis of the cyclotron beam intensity needs to be combined with the changes in multiple beam control parameters to obtain accurate analysis results of the beam stability deviation.

[0054] Furthermore, based on the above analysis, a comparative analysis of the stability of the beam current intensity during actual use was conducted to determine the differences in the stability characteristics of the medical cyclotron control process in different application scenarios.

[0055] Step 2.1: Obtain probability distribution curves of various beam control parameter data, and determine a 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 the any two beam control parameter data.

[0056] Because changes in the vacuum environment, magnetic field, and radio frequency power during the use of a medical cyclotron can affect the particle velocity, energy, and direction of the beam, the stability analysis of the beam intensity in a medical cyclotron requires comprehensive consideration of the correlation differences between the data changes of different beam control parameters. When different beam control parameters are affected by beam stability during actual use, the distribution of these parameters will vary. Therefore, probability statistics are performed on the data of various beam control parameters, and curve fitting is performed on the probability statistical results. The resulting fitting curves are used as probability distribution curves for the various beam control parameter data. The probability distribution curves represent the distribution of each beam control parameter during the use of the medical cyclotron. Specifically, under normal circumstances, the distribution of each beam control parameter in a medical cyclotron should be concentrated, specifically manifested as a single peak or spike.

[0057] In this embodiment, the least squares method is used to perform curve fitting on the probability statistical results. As other implementation methods, on the basis of being able to perform curve fitting on the probability statistical results, the implementer may use other existing technologies for curve fitting, such as local weighted regression, K-nearest neighbor regression, etc., and this application does not impose any special restrictions.

[0058] Furthermore, during the use of a medical cyclotron, if the beam current stability deviates, the deviation in the beam current stability will affect the distribution state of multiple beam control parameters, including the environment, magnetic field strength and power. That is, there are differences in the responses of vacuum degree, magnetic field strength and power to the stability deviation, resulting in large differences in the peak states of the distributions of different beam control parameters, and differences in the peak shape and peak offset changes. Therefore, the skewness coefficient and kurtosis coefficient of the probability distribution curve of each beam control parameter data are obtained; the difference in the skewness coefficient and the peak value between any two beam control parameter data are calculated. The difference in the coefficients of skewness and kurtosis are recorded as skewness difference and kurtosis difference respectively, and the mean of the skewness difference and the kurtosis difference between any two beam control parameter data is used as the stable deviation value of the state response between any two beam control parameter data; the larger the stable deviation value is, the greater the distribution difference of any two beam control parameter data is during the operation of the medical cyclotron; further, the correlation coefficient between any two beam control parameter data is calculated, and the larger the correlation coefficient is, the more significant the overall correlation characteristics of the two beam control parameter data over time during operation. Among them, the calculation process of the skewness coefficient and the kurtosis coefficient of the probability distribution curve is a well-known technology and will not be repeated in this application. The schematic diagram of the flow chart for determining the stable deviation value is shown in the figure below. Figure 2 shown.

[0059] In this embodiment, in the process of calculating the stable deviation value, the differences involved are all absolute values of the differences. As other implementation methods, based on the differences between measurable skewness coefficients and kurtosis coefficients, the implementer can use other calculation methods for measurement, such as ratios, squares of differences, etc. This application does not impose any special restrictions.

[0060] In this embodiment, the correlation coefficient between the two beam control parameter data is the Pearson correlation coefficient. As other implementation methods, on the basis of being able to measure the correlation between the two beam control parameter data, the implementer may use other existing technologies for measurement, such as the Spearman correlation coefficient, the Kendall rank correlation coefficient, etc., and this application does not impose any special restrictions.

[0061] Step 2.2: determining confidence difference values of various beam control parameter data based on the correlation between various beam control parameter data and all other beam control parameter data, and the stable deviation values therebetween.

[0062] The expressions of the confidence difference values of the various beam control parameter data are as follows:

[0063] Where, Indicates the Confidence difference value of the beam control parameter data; Indicates the Kind and The stable deviation value of the state response between the beam control parameter data; Indicates the Kind and The correlation coefficient between the beam control parameter data; It represents an exponential function with a natural constant as the base, in order to avoid the denominator being 0; Indicates the number of types of beam control parameters.

[0064] It should be noted that the larger the calculated confidence difference value is, the more accurate the analysis of the parameter characteristics of the medical cyclotron is. The greater the difference in stability characteristics between the seed beam control parameter data and the other seed beam control parameter data, the greater the difference in the correlation distribution of the overall parameter changes between them.

[0065] Step 2.3: Based on the sudden change of the beam current intensity data, the acquisition time is divided into various time intervals. Based on the confidence difference value and the difference in the degree of discreteness between the various beam control parameter data in each time interval and all other beam control parameter data, the response difference value of the various beam control parameter data in each time interval is determined.

[0066] Through the above analysis, a comparative analysis was conducted on the overall characteristic differences of different beam control parameter data changing over time during the operation of the medical cyclotron. The purpose is to accurately extract the associated state characteristics between different beam control parameter data based on the differences in the correlation between the environment, magnetic field, power, energy and beam intensity, as well as the direct or indirect influence of the state characteristic differences during the operation of the medical cyclotron, and then accurately analyze the impact of different beam control parameters on the deviation of beam stability during the beam control process.

[0067] During the use of a medical cyclotron, if the beam stability deviates in a short period of time, it may be due to the disturbance of parameters such as the environment, magnetic field, and power, which leads to a decrease in beam stability and makes it impossible to ensure that the beam particles are stably accelerated along the trajectory at the set flux intensity. Therefore, considering that different beam control parameters have different response characteristics to beam stability deviations 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 difference of parameter changes of different beam control parameters in the same time period is used to accurately highlight the local influence characteristics of different control parameters when analyzing stability deviations; 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. The purpose is to quantify the comparative differences between different beam control parameters and highlight the local comparative characteristics between different beam control parameters.

[0068] Furthermore, during the use of a medical cyclotron, the influences of different control parameters occur successively, that is, changes in vacuum, 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 within a short period of time; therefore, all the collected beam flux data are arranged in time sequence to form a control parameter sequence, and a mutation point detection algorithm is used to obtain the mutation point in the control parameter sequence. The acquisition time is divided according to the time of the mutation point to obtain each time interval.

[0069] 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. This application does not impose any special restrictions.

[0070] 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 、 、 、 、 , the time interval is divided into .

[0071] 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 is calculated to reflect the local stability characteristics of each beam control parameter during the control process of the medical cyclotron.

[0072] In this embodiment, the degree of discreteness is the coefficient of variation. As other implementation methods, based on the ability to measure the uneven distribution of each beam control parameter data in each time interval, the implementer may use other existing technologies for measurement, such as variance, standard deviation, etc. This application does not impose any special restrictions.

[0073] Based on the confidence difference value and the difference in discreteness between the various beam control parameter data in each time interval and all other beam control parameter data, the response difference value of the various beam control parameter data in each time interval is determined, and the expression is:

[0074] Where, Indicates the The beam control parameter data is The response difference value within the time interval; 、 Respectively represent In the time interval Type, The discrete degree of the beam control parameter data; 、 Respectively represent Type, The proportion of the beam control parameter data; represents the maximum value function; Indicates the number of types of beam control parameters.

[0075] It should be noted that the larger the calculated response difference value is, the more accurate the local stability characteristics comparison is during the operation of the medical cyclotron. The more significant the local correlation effect of the beam control parameters, the more significant the characteristics. The flow chart for determining the response difference value is as follows: Figure 3 shown.

[0076] Step 2.4: 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.

[0077] During the use of the medical cyclotron, the response deviation in the beam intensity control process is accurately analyzed in combination with the analysis results of the local correlation influence characteristics of the beam intensity data up to the current moment. Specifically, the average of the normalized values of the response difference values of the beam intensity data in all time intervals is used as the deviation response value of the beam intensity data at the current moment.

[0078] In this embodiment, the Z-Score normalization method is used to normalize the response difference value. As other implementation methods, on the basis of being able to normalize the response difference value, the implementer can use other existing technologies to normalize the response difference value, such as the Min-Max normalization method, the decimal calibration normalization method, etc., and this application does not impose any special restrictions.

[0079] It should be noted that: the larger the deviation response value, the greater the possibility that the beam current intensity response will differ due to the influence of environmental changes and changes in related parameters during the operation of the medical cyclotron; the smaller the deviation response value, the smaller the possibility that the beam current intensity response will differ due to the influence of environmental changes and changes in related parameters during the operation of the medical cyclotron.

[0080] Step 3: adjusting the feedback signal value at the current moment based on the deviation response value, and controlling the beam current intensity in the medical cyclotron based on the adjusted feedback signal value.

[0081] In the process of controlling beam intensity, if the variation characteristics of different control parameters are analyzed and the response of beam intensity varies significantly, then the beam intensity error should also be large during the actual feedback adjustment process. Therefore, the deviation of the currently fed-back beam intensity is adjusted based on the deviation response value of the current beam intensity data. The specific adjustment relationship is: ; Indicates the adjusted feedback signal value at the current moment; Indicates the feedback signal value before adjustment at the current moment; Indicates the deviation response value of the beam current intensity data at the current moment; Indicates that the preset value is greater than 0, in order to avoid the feedback signal value after adjustment being too small. The value of is preset by humans and can be set by the implementer. The value of is 0.5.

[0082] Based on the adjusted feedback signal value at the current moment, a PID controller is used to feedback control the beam flux in the medical cyclotron. The specific parameters of the PID controller can be determined by the attenuation curve method. The specific use of the PID controller is well known to those skilled in the art and will not be repeated in this application.

[0083] In summary, the present application addresses the problem that existing methods fail to fully consider the relationship between changes in beam stability and changes in various beam control parameters during actual use, resulting in large deviations in feedback signals and affecting the accuracy of beam intensity control. Based on the shape difference of the probability distribution curves 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 all other types of beam control parameter data, and the stable deviation values between them, the confidence difference value of the various beam control parameter data is determined; the beneficial effect is that, by combining the stability differences and correlation differences between various beam control parameter data during actual use of a medical cyclotron, the overall characteristic differences of different types of beam control parameter data over time are compared and analyzed, which is conducive to accurately extracting the correlation state characteristics between different types of beam control parameter data;

[0084] Furthermore, based on the sudden change of the beam intensity data, the acquisition time is divided into various time intervals. Based on the confidence difference value and the difference in the degree of dispersion between the various beam control parameter data and all other beam control parameter data in each time interval, the response difference value of the various beam control parameter data in each time interval is determined. This has the beneficial effect of considering the different response characteristics of different beam control parameters to beam stability deviations in the actual control process, combining the state correlation characteristics of different control parameters when stability deviations occur, and accurately highlighting the local influence characteristics of different control parameters on stability deviation analysis through the confidence difference of parameter changes of different beam control parameters in the same time period.

[0085] Furthermore, based on the distribution of response differences of the beam intensity data across all time intervals, the deviation response value of the beam intensity data at the current moment is obtained. This has the beneficial effect of determining the possibility of differences in beam intensity responses by analyzing multiple beam control parameter data over a long period of time. This allows for the capture of anomalies that may occur in different time intervals, thereby providing more accurate beam stability analysis results.

[0086] Furthermore, the feedback signal value at the current moment is adjusted based on the deviation response value, and the beam intensity in the medical cyclotron is controlled based on the adjusted feedback signal value; the beneficial effect is that the feedback signal is accurately adjusted based on the response deviation in the beam intensity control process, thereby improving the control accuracy of the beam intensity of the cyclotron.

[0087] The flowcharts and block diagrams in the accompanying drawings show the possible implementation architectures, functions and operations of the systems, methods and computer program products according to the embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment or part of the code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical functions. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

[0088] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic characteristics of the present application. Therefore, from all perspectives, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. A method for controlling the beam intensity of a medical cyclotron, characterized in that: The method comprises the following steps: Real-time acquisition of various beam control parameter data of medical cyclotron at each acquisition moment, including beam intensity data; Obtaining probability distribution curves of various beam control parameter data, and determining a stable deviation value of a state response between any two beam control parameter data based on a shape difference of the probability distribution curves between the any two beam control parameter data; determining confidence difference values of the various beam control parameter data based on correlations between the various beam control parameter data and all other beam control parameter data, and the stable deviation values therebetween; Based on the sudden change of the beam current intensity data, the acquisition time is divided into various time intervals, and based on the confidence difference value and the difference in the degree of dispersion between the various beam control parameter data in each time interval and all other beam control parameter data, the response difference value of the various beam control parameter data in each time interval is determined; Based on the distribution of the response difference values of the beam intensity data in all time intervals, the deviation response value of the beam intensity data at the current moment is obtained; The feedback signal value at the current moment is adjusted based on the deviation response value, and the beam current intensity in the medical cyclotron is controlled based on the adjusted feedback signal value.

2. A medical cyclotron beam intensity control method according to claim 1, characterized in that: The acquisition process of the probability distribution curve is: performing probability statistics on various beam control parameter data respectively, and obtaining the probability distribution curves of the various beam control parameter data according to the probability statistics results.

3. The method for controlling the beam intensity of a medical cyclotron according to claim 1, wherein: 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; Calculating the difference in skewness coefficient and kurtosis coefficient between any two beam control parameter data, which are recorded as skewness difference and kurtosis difference respectively; The stable deviation value is positively correlated with the skewness difference and the kurtosis difference, respectively.

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

5. The method for controlling the beam intensity of a medical cyclotron according to claim 1, wherein: The expression of the confidence difference value is: Where, Indicates the Confidence difference value of the beam control parameter data; Indicates the Species and The stable deviation value of the state response between the beam control parameter data; Indicates the Kind and The correlation coefficient between the beam control parameter data; represents an exponential function with a natural constant as its base; Indicates the number of types of beam control parameters.

6. The method for controlling the beam intensity of a medical cyclotron according to claim 1, wherein: The method for obtaining the time interval is as follows: all the collected beam current intensity data are arranged in time sequence to form a control parameter sequence, and the collection time is divided according to the time of the mutation point in the control parameter sequence to obtain each time interval.

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

8. The method for controlling the beam intensity of a medical cyclotron according to claim 7, wherein: The expression of the response difference value is: Where, Indicates the The beam control parameter data is The response difference value within the time interval; 、 Respectively represent In the time interval Type, The discrete degree of the beam control parameter data; 、 Respectively represent Type, The proportion of the beam control parameter data; represents the maximum value function; Indicates the number of types of beam control parameters.

9. The method for controlling beam intensity of a medical cyclotron according to claim 1, wherein: The deviation response value is the average of the normalized values of the response difference values of the beam current intensity data in all time intervals.

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

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