A method and device for monitoring dark current induced by deflection of a medical cyclotron
By analyzing the stability and interaction of beam current and dark current in segments, combining Arima and CA algorithms, the sampling frequency is dynamically adjusted, which solves the accuracy and noise interference problems of dark current monitoring in medical cyclotrons, and improves operating efficiency and safety sex.
Patent Information
- Application Number
- CN202411406329.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-10
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2044-10-10
AI Technical Summary
The dark currents derived from deflection in medical cyclotrons are difficult to accurately monitor, especially in the context of strong beam current signals, weak dark current signals may be masked, resulting in difficulty in monitoring and difficult to balance the data volume and information acquisition of sampling frequency.
By collecting beam current intensity and dark current data, analyzing its stability and interactions in segments, using the Arima algorithm for time series analysis, combining the significance detection CA algorithm to dynamically adjust the sampling frequency to capture tiny changes in dark current and identify significance change.
It significantly improves the operating efficiency and safety of medical cyclotrons, optimizes resource allocation and data processing processes, reduces noise interference, improves data processing efficiency and accuracy, ensures timely adjustment of accelerator parameters, and ensures high efficiency and reliability.
Smart Images
Figure CN118914642B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of data processing, and in particular to a method and a device for monitoring dark current induced by deflection of a medical cyclotron. Background Art
[0002] Medical cyclotrons are often used to produce radioactive isotopes for diagnosis and treatment. During the deflection process, a series of changes caused by the interaction between high-energy particles and the accelerator structure will lead to the formation of dark current. To ensure the efficient and safe operation of medical cyclotrons, it is necessary to accurately monitor and effectively control the dark current. By analyzing the dark current data, the operator can adjust the accelerator parameters, such as magnetic field strength and RF power, to minimize the adverse effects of dark current on beam quality and radioactive isotope yield.
[0003] The dark current induced by deflection in medical cyclotrons is usually monitored by high-precision current measurement equipment and radiation detectors. However, dark current usually has a very low current intensity, which makes it difficult to measure directly and accurately. Against the background of strong beam signals, weak dark current signals may be masked, resulting in monitoring difficulties. Therefore, choosing the right sampling frequency is crucial to capturing small changes in dark current. Too high a sampling frequency may result in too much data, while too low a sampling frequency may miss important information. The beam current and dark current are closely related. By analyzing the relationship between the beam current and the dark current, the sampling frequency can be dynamically adjusted to more accurately monitor the dark current. Summary of the invention
[0004] The invention provides a method and device for monitoring dark current induced by deflection of a medical cyclotron accelerator, so as to solve the existing problems.
[0005] The present invention provides a method and device for monitoring dark current induced by deflection of a medical cyclotron accelerator, which adopts the following technical solutions:
[0006] The present invention proposes a method for monitoring dark current induced by deflection of a medical cyclotron, the method comprising the following steps:
[0007] Collect beam intensity and dark current data in medical cyclotrons and record the rotation period of cyclotrons;
[0008] The beam intensity and dark current data are segmented based on the rotation period, and the stability of each segment of beam intensity is obtained according to the numerical difference in each segment of beam intensity, and the stability of each segment of dark current data is obtained;
[0009] According to the stability of the beam intensity and dark current data, the slopes of the two stability straight lines of the beam intensity and the dark current and the two stability curves of the beam intensity and the dark current are obtained, and then the degree of interaction between the beam intensity and the dark current data is obtained; according to the time series distribution of the beam intensity, the predicted intensities of several beam intensities are obtained, and the predicted degree of change of each section of the beam intensity is obtained in combination with the beam intensity; according to the predicted degree of change of each section of the beam intensity and the degree of interaction between the beam intensity and the dark current data, the predicted change trend of each section of the dark current data is obtained;
[0010] According to the initial sampling frequency and the predicted change trend of each section of dark current data, the adjusted sampling frequency of each section of dark current data is obtained;
[0011] The dark current is dynamically collected according to the sampling frequency adjusted for each segment of dark current data, and the collected dark current data is analyzed using a significance detection CA algorithm to obtain significant changes in the dark current data.
[0012] Furthermore, the beam intensity and dark current data are segmented based on the rotation period, and the stability of each segment of beam intensity is obtained according to the numerical difference in each segment of beam intensity, and the stability of each segment of dark current data is obtained, including the following specific steps:
[0013] The beam intensity and dark current data are segmented respectively according to the rotation period of the cyclotron to obtain several segments of beam intensity and several segments of dark current data;
[0014] The stability of the beam intensity in each section is calculated by the following specific formula:
[0015]
[0016] in, Indicates The stability of the beam intensity; Indicates Standard deviation of the segment beam intensity; Indicates the number of beam intensities in each beam intensity segment; Indicates The beam intensity of the first beam intensity value; Indicates The maximum beam intensity value among the segment beam intensities; Indicates The minimum beam intensity value in the segment beam intensity; represents the absolute value function; represents an exponential function with a natural constant as base;
[0017] The dark current data is processed in the same segmentation manner, and the stability of each segment of the dark current data is obtained.
[0018] Furthermore, the slopes of two stability straight lines of beam intensity and dark current and two stability curves of beam intensity and dark current are obtained according to the stability of beam intensity and dark current data, and the specific steps include the following:
[0019] The order of the segments is taken as the horizontal coordinate, and the stability of each segment of the beam intensity and each segment of the dark current data is taken as the vertical coordinate. The beam intensity and dark current data of all segments are plotted as scatter plots, and the stability of the beam intensity and dark current data in the scatter plots are fitted with straight lines by the least square method to obtain two stability straight lines and their slopes for the beam intensity and dark current data.
[0020] The stability of the beam intensity and dark current data in each segment of the scatter plot are connected respectively to obtain two stability curves of the beam intensity and dark current data.
[0021] Furthermore, the step of obtaining the interaction degree between beam intensity and dark current data includes the following specific steps:
[0022]
[0023] in, Indicates the degree of interaction between beam intensity and dark current data; The slope of the stability line representing the beam intensity; The slope of the stability line representing the dark current data; represents the stability curve representing the beam intensity; shows the stability curve representing the dark current data; Indicates calculating the DTW distance between two curves; represents the absolute value function; Represents the sigmoid function; Represents an exponential function with a natural constant as its base.
[0024] Furthermore, the step of obtaining predicted intensities of a plurality of beam intensities according to the time series distribution of the beam intensity includes the following specific steps:
[0025] The time series of beam intensity is analyzed by Arima algorithm to obtain the predicted intensity of several beam intensities.
[0026] Furthermore, the step of obtaining the predicted variation degree of each beam intensity segment includes the following specific steps:
[0027]
[0028] in, Indicates The predicted degree of variation of the beam intensity in the segment; Indicates The stability of the beam intensity; Indicates The number of predicted intensities in the segment beam intensity; Indicates The beam intensity in the first The prediction strength; represents the mean of all beam intensity values; represents the absolute value function; Represents an exponential function with a natural constant as its base.
[0029] Furthermore, the predicted change trend of each section of dark current data is obtained according to the predicted change degree of each section of beam intensity and the degree of interaction between beam intensity and dark current data, and the specific steps include the following:
[0030] Calculate the interaction degree between beam intensity and dark current data and the The product of the predicted variation degree of the beam intensity of the first segment is recorded as Predicted change trend of dark current data in the segment.
[0031] Furthermore, the method of obtaining the adjusted sampling frequency of each segment of dark current data according to the initial sampling frequency and the predicted change trend of each segment of dark current data includes the following specific steps:
[0032] Calculate 1 and The product of the initial sampling frequency and the predicted change trend of the dark current data of the first segment is recorded as The dark current data of this segment has an adjusted sampling frequency.
[0033] Furthermore, the dark current is dynamically collected according to the sampling frequency adjusted according to each section of dark current data, and the specific steps include the following:
[0034] During the normal operation of the medical cyclotron, the dark current data is collected using the sampling frequency adjusted for the latest dark current data, and the adjusted sampling frequency for the next dark current data is obtained, and the data is collected backwards according to the adjusted sampling frequency, and so on, until the cyclotron is completed and the dark current data collection is completed.
[0035] The present invention also proposes a dark current monitoring device derived from the deflection of a medical cyclotron accelerator, the device comprising:
[0036] A data acquisition module, a data processing module and a data detection module; wherein the data acquisition module is used to collect beam intensity and dark current data in a medical cyclotron, the data processing module obtains the adjusted sampling frequency of each section of dark current data through the steps of a dark current monitoring method induced by deflection of a medical cyclotron, the data detection module dynamically collects dark current according to the adjusted sampling frequency of each section of dark current data, and detects significant changes in the collected dark current data.
[0037] The beneficial effects of the technical solution of the present invention are:
[0038] Through accurate dark current monitoring and effective dynamic adjustment, the operation efficiency and safety of medical cyclotrons have been significantly improved, and resource allocation and data processing processes have been optimized. Specifically, by segmenting the beam intensity and dark current data and obtaining their stability respectively, accurate data analysis is ensured; combining the stability curves and slopes of beam intensity and dark current, the degree of interaction between beam intensity and dark current data is accurately calculated; using the Arima algorithm for time series analysis, several beam intensity prediction values are obtained, which improves the accuracy of the prediction; the dynamically collected dark current data is analyzed by the significance detection CA algorithm to identify significant changes in the data; according to the predicted change trend of the dark current data, the sampling frequency is dynamically adjusted to avoid data redundancy and information omission caused by too high or too low sampling frequency; by dynamically collecting dark current data, noise interference is effectively reduced, and the efficiency and accuracy of data processing are improved; by real-time monitoring and adjustment of dark current, the operator can adjust the accelerator parameters in time, reducing the adverse effects of dark current on beam quality and radioisotope yield, and ensuring the efficiency and reliability of medical cyclotrons in the process of producing radioisotopes. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0040] Figure 1 The present invention is a flowchart of the steps of a method for monitoring dark current induced by deflection of a medical cyclotron. DETAILED DESCRIPTION
[0041] Figure 1 , which shows a flowchart of a method for monitoring dark current induced by deflection of a medical cyclotron provided by an embodiment of the present invention, the method comprising the following steps:
[0042] Step S001: Collect beam intensity and dark current data in a medical cyclotron, and record the rotation period of the cyclotron.
[0043] The purpose of this embodiment is to predict the changing trend of the dark current in the medical cyclotron, thereby realizing dynamic monitoring and real-time adjustment of the dark current. Therefore, it is necessary to collect the dark current data through a beam detector.
[0044] It should be noted that when a particle beam passes through a beam detector, it will cause corresponding physical reactions (such as luminescence or ionization). The signals generated by these physical reactions can be read by the beam detector after conversion (such as photoelectric conversion), thereby enabling real-time collection and recording.
[0045] Specifically, the beam detector is placed at the exit of the particle guide tube and before the sample stage. The collected output signal is transmitted to the data acquisition system through the detector. The beam intensity is continuously measured and recorded by recording and analyzing the data in real time and providing instant feedback on the beam intensity. In the load circuit of the medical cyclotron, the dark current is monitored in real time through current transformers and monitoring instruments, and the collected data is filtered and denoised to obtain denoised dark current data. The rotation period of the cyclotron is recorded, and the beam intensity and dark current data are aligned in time series.
[0046] Step S002: segmenting the beam intensity and dark current data based on the rotation period, obtaining the stability of each segment of beam intensity according to the numerical difference in each segment of beam intensity, and obtaining the stability of each segment of dark current data.
[0047] It should be noted that due to the weakness of dark current, its current intensity may be comparable to the electronic noise level of the monitoring equipment. If the trend of dark current changes is predicted directly through historical dark current monitoring data, the monitoring accuracy will be low. The intensity and energy of the beam will affect the generation of dark current, and there is interaction and mutual influence between the beam and dark current. Therefore, by analyzing the relationship between beam current and dark current, the trend of dark current changes can be predicted, and the sampling frequency can be adjusted to capture small changes in dark current.
[0048] It should be further explained that the dark current is usually very weak, with an intensity at the nanoampere (nA) or even picoampere (pA) level, and is easily interfered by noise. It is challenging to measure and process, and it is also difficult to predict. However, the change of dark current reflects the problem in the deflection process of the cyclotron. In order to capture the slight change of dark current caused by the deflection problem of the cyclotron and prevent the prediction error caused by noise interference, it is necessary to indirectly predict the change trend of dark current through beam data closely related to dark current. In medical cyclotrons, the beam intensity directly affects the magnitude of dark current. The beam is generated by the acceleration of high-energy particles, and some of these particles may deviate from the predetermined trajectory to form "dark current". The beam changes during the operation of the accelerator due to various factors (such as the pressure of the ion source gas, the stability of the magnetic field, etc.), and is reflected in the performance of dark current. Therefore, by monitoring the beam intensity generated by the medical cyclotron and analyzing the relationship between the beam intensity and the dark current, the change trend of the dark current can be indirectly inferred. When analyzing the relationship between the beam intensity and the dark current, the beam intensity can be analyzed in segments. In a medical cyclotron, charged particles repeatedly rotate in a magnetic field, perform isochronous cyclotron acceleration, and draw out a beam with a constant rotation period. Through the above analysis, we can more accurately capture the slight changes in dark current and provide effective monitoring and prediction of cyclotron performance.
[0049] Specifically, the beam intensity is segmented according to the rotation period of the cyclotron to obtain several sections of beam intensity; according to each section of beam intensity, the stability of each section of beam intensity can be obtained, and the specific calculation formula is:
[0050]
[0051] in, Indicates The stability of the beam intensity; Indicates Standard deviation of the segment beam intensity; Indicates the number of beam intensities in each beam intensity segment; Indicates The beam intensity of the first beam intensity value; Indicates The maximum beam intensity value among the segment beam intensities; Indicates The minimum beam intensity value in the segment beam intensity; represents the absolute value function; represents an exponential function with a natural constant as the base. In this embodiment, Model to present inverse proportional relationship and normalization, As the input of the model, the implementer can set the inverse proportional function and normalization function according to the actual situation.
[0052] It should be noted that Indicates The coefficient of variation of the beam intensity of a segment is expressed by the ratio of the standard deviation to the mean value. The smaller the coefficient of variation, the more stable the beam intensity of the segment. Indicates The difference between the maximum beam intensity value and the minimum beam intensity value in the segment beam intensity is the fluctuation range of the beam intensity in this segment. The smaller the difference is, the smaller the fluctuation of the beam intensity in this segment is concentrated in a smaller range, indicating that the stability of the beam intensity in this segment is stronger.
[0053] At this point, the stability of the beam intensity in each segment is obtained; similarly, the dark current data is subjected to the same segmentation processing, and the stability of the dark current data in each segment is obtained.
[0054] Step S003: According to the stability of the beam intensity and dark current data, the slopes of two stability straight lines of the beam intensity and the dark current and two stability curves of the beam intensity and the dark current are obtained, and then the degree of interaction between the beam intensity and the dark current data is obtained; according to the time series distribution of the beam intensity, several predicted intensities of the beam intensities are obtained, and the predicted degree of change of each section of the beam intensity is obtained in combination with the beam intensity; according to the predicted degree of change of each section of the beam intensity and the degree of interaction between the beam intensity and the dark current data, the predicted change trend of each section of the dark current data is obtained.
[0055] It should be noted that since the dark current changes are relatively weak and are at the same level as the noise, it is greatly affected by the noise. It is impossible to predict the trend of dark current changes based on historical data. Therefore, the trend of dark current changes can only be predicted through the relationship between beam current and dark current. In medical cyclotron accelerators, the beam current and dark current will affect each other. The deviated particles in the beam will generate dark current. When the beam intensity increases or the stability improves, the dark current will increase accordingly, because more particles may deviate from the predetermined orbit, thus converting into dark current. This conversion may be caused by a variety of factors, such as changes in the electromagnetic field in the accelerator, mechanical vibrations, or instability of the beam itself. Therefore, changes in dark current can reflect fluctuations in the beam state. If the dark current suddenly increases or decreases, it means that there may be problems in the beam, such as unstable beam intensity, deviation of particle orbits, or abnormalities in the acceleration process.
[0056] Specifically, the order value of the segment is taken as the horizontal coordinate, and the stability of each segment of the beam intensity and each segment of the dark current data is taken as the vertical coordinate. The beam intensity and dark current data of all segments are plotted as scatter plots, and the stability of the beam intensity and dark current data in the scatter plots are linearly fitted by the least squares method to obtain two stability straight lines and slopes of the beam intensity and dark current data; at the same time, the stability of the beam intensity and dark current data of each segment in the scatter plot is connected to obtain two stability curves of the beam intensity and dark current data; according to the slopes of the two stability straight lines of the beam intensity and dark current and the two stability curves, the degree of interaction between the beam intensity and dark current data is obtained, and the specific calculation formula is:
[0057]
[0058] in, Indicates the degree of interaction between beam intensity and dark current data; The slope of the stability line representing the beam intensity; The slope of the stability line representing the dark current data; represents the stability curve representing the beam intensity; shows the stability curve representing the dark current data; represents the absolute value function; Indicates calculating the DTW distance between two curves; represents a sigmoid function, and this embodiment uses the sigmoid function for normalization processing; represents an exponential function with a natural constant as the base. In this embodiment, The model shows an inverse proportional relationship. As the input of the model, the implementer can set the inverse proportional function according to the actual situation.
[0059] It should be noted that represents the difference in the slope of the stability line between the beam intensity and the dark current data. The slope of the stability line between the beam intensity and the dark current data represents the change trend of the beam intensity and the dark current data. That is, it indicates the difference in the stability change trend between the beam intensity and the dark current data. The smaller the difference, the more consistent the stability change trend of the beam intensity and the dark current data are, and the greater the interaction between the beam intensity and the dark current data is. It represents the matching distance of the stability curves of beam intensity and dark current data, that is, the similarity between the two types of data. The smaller the value, the greater the similarity between the stability changes of beam intensity and dark current data over time, and the greater the mutual influence and interaction between beam intensity and dark current.
[0060] It should be noted that the beam intensity directly reflects the number of particles per unit time and area in the particle accelerator, and directly affects the degree of interaction between particles and the accelerator structure. The interaction between particles and the accelerator structure will produce secondary particles and other electromagnetic effects, including the generation of dark current. Therefore, by understanding the changes in beam intensity, the trend of dark current changes can be indirectly inferred. Experimental data show that in high-current pulsed ion beam experiments, the state of the material surface is extremely sensitive to beam intensity, and changes in beam intensity will directly affect the generation of dark current. Therefore, it can be used as a method to support indirect prediction through beam intensity. The important characteristic of dark current is its weakness. Direct measurement of dark current may be affected by many factors such as equipment accuracy and environmental noise. By performing time series analysis on beam intensity, more stable and accurate prediction data can be provided, which can smooth short-term fluctuations and capture long-term trends, thereby improving the reliability of prediction. At the same time, direct prediction of dark current requires complex models to deal with various uncertainties and nonlinear factors, while indirect prediction of dark current through beam intensity can use rich beam intensity data with mature monitoring technology to reduce the generation of errors.
[0061] Specifically, the time series of beam intensity is analyzed by using the Arima algorithm to obtain the predicted intensity of several beam intensities. The Arima algorithm is a common and well-known algorithm, and the specific steps are not repeated here. According to the degree of interaction between the beam intensity and the dark current data and the predicted intensity of the beam intensity, the change trend of the dark current data is predicted, and the specific calculation formula for the predicted change degree of each section of the beam intensity is obtained:
[0062]
[0063] in, Indicates The predicted degree of variation of the beam intensity in the segment; Indicates The stability of the beam intensity; Indicates The number of predicted intensities in the segment beam intensity; Indicates The beam intensity in the first The prediction strength; represents the mean of all beam intensity values; represents the absolute value function; represents an exponential function with a natural constant as the base. In this embodiment, Model to present inverse proportional relationship and normalization, As the input of the model, the implementer can set the inverse proportional function and normalization function according to the actual situation.
[0064] It should be noted that The average value of all beam intensity values is The difference between the mean values of the predicted intensity values in the segment beam intensity indicates the difference between the predicted value obtained by time series analysis and the average level of beam intensity. The larger the value, the greater the degree of change in the predicted beam intensity of the segment.
[0065] Furthermore, according to the predicted change degree of each section of beam intensity and the interaction degree between beam intensity and dark current data, the predicted change trend of each section of dark current data is obtained. The specific calculation formula is:
[0066]
[0067] in, Indicates Predicted change trend of segment dark current data; Indicates the degree of interaction between beam intensity and dark current data; Indicates The predicted degree of change of the segment beam intensity; it should be noted that since the beam intensity and dark current data are segmented based on the rotation period of the cyclotron, a segment of beam intensity and a segment of dark current data with the same order value have the same length and the same time series distribution position, so they can correspond directly.
[0068] Step S004: obtaining the adjusted sampling frequency of each section of dark current data according to the initial sampling frequency and the predicted change trend of each section of dark current data.
[0069] It should be noted that the purpose of monitoring the dark current induced during the deflection of a medical cyclotron accelerator is to discover problems in the operation of the accelerator through changes in the dark current, thereby adjusting the accelerator magnetic field settings and accurately controlling the radiation dose. Since the real-time changes in the dark current are of great significance, when the dark current data to be monitored has a possible trend or possibility of change, it is necessary to set a higher sampling frequency to capture the specific details of the dark current changes.
[0070] Specifically, the specific calculation formula for the adjusted sampling frequency of each segment of dark current data is:
[0071]
[0072] in, Indicates The sampling frequency of the dark current data after adjustment; represents the initial sampling frequency; Indicates Predicted change trend of dark current data in the segment.
[0073] It should be noted that the initial sampling frequency is the common sampling frequency in the medical cyclotron industry. It means that when The greater the predicted change trend of a segment of dark current data is, the more likely it is that there are change details in this segment of dark current data that need to be paid attention to and analyzed, and the change details need to be amplified to capture them. Therefore, the sampling frequency of this segment of data needs to be increased to observe the specific changes in this segment of dark current data and realize the observation of the operating status of the cyclotron.
[0074] Step S005: dynamically collect dark current according to the adjusted sampling frequency of each segment of dark current data, analyze the collected dark current data by using the significance detection CA algorithm, and obtain the significance changes in the dark current data.
[0075] It should be noted that by collecting the dark current at the adjusted sampling frequency for each segment of dark current data, the details of the changes in the dark current can be effectively captured. The larger the adjusted sampling frequency, the more important the dark current changes in that segment are.
[0076] Specifically, during the normal operation of the medical cyclotron, the dark current data is collected using the sampling frequency adjusted for the latest dark current data, and the adjusted sampling frequency for the next dark current data is obtained according to the above method, and the dark current data is collected according to the adjusted sampling frequency, and so on, until the cyclotron is completed and the dark current data collection is completed. In this way, the dark current data monitored at different sampling frequencies are continuously obtained to avoid the omission of important data. The dark current data obtained by sampling the dynamically adjusted sampling frequency (i.e., the dark current data monitored at different sampling frequencies) is analyzed by the significance detection CA algorithm for its average value, peak value, and irregular changes (different from the change pattern in the historical records). When there is a significant change in the dark current data, the operator of the medical cyclotron is prompted to perform further manual diagnosis, and the accelerator parameters are adjusted in time based on the monitoring and analysis results to ensure the beam quality and the yield of radioactive isotopes.
[0077] At this point, this embodiment is completed.
[0078] The present invention also provides a dark current monitoring device for deflection induced by a medical cyclotron, the device comprising a data acquisition module, a data processing module and a data detection module; wherein the data acquisition module is used to collect beam intensity and dark current data in the medical cyclotron, the data processing module implements steps S001 to S005 of the above method by calling a computer program to obtain the adjusted sampling frequency of each segment of dark current data, the data detection module dynamically collects the dark current according to the adjusted sampling frequency of each segment of dark current data, and detects significant changes in the collected dark current data.
[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for monitoring dark current induced by deflection of a medical cyclotron, characterized in that: The method comprises the following steps: Collect beam intensity and dark current data in medical cyclotrons and record the rotation period of cyclotrons; The beam intensity and dark current data are segmented based on the rotation period, and the stability of each segment of beam intensity is obtained according to the numerical difference in each segment of beam intensity, and the stability of each segment of dark current data is obtained; According to the stability of the beam intensity and dark current data, the slopes of the two stability straight lines of the beam intensity and the dark current and the two stability curves of the beam intensity and the dark current are obtained, and then the degree of interaction between the beam intensity and the dark current data is obtained; according to the time series distribution of the beam intensity, the predicted intensities of several beam intensities are obtained, and the predicted degree of change of each section of the beam intensity is obtained in combination with the beam intensity; according to the predicted degree of change of each section of the beam intensity and the degree of interaction between the beam intensity and the dark current data, the predicted change trend of each section of the dark current data is obtained; According to the initial sampling frequency and the predicted change trend of each section of dark current data, the adjusted sampling frequency of each section of dark current data is obtained; The dark current is dynamically collected according to the sampling frequency adjusted for each segment of dark current data, and the collected dark current data is analyzed using a significance detection CA algorithm to obtain significant changes in the dark current data.
2. A method for monitoring dark current derived from deflection of a medical cyclotron according to claim 1, characterized in that: The beam intensity and dark current data are segmented based on the rotation period, and the stability of each segment of beam intensity is obtained according to the numerical difference in each segment of beam intensity, and the stability of each segment of dark current data is obtained, including the following specific steps: The beam intensity and dark current data are segmented respectively according to the rotation period of the cyclotron to obtain several segments of beam intensity and several segments of dark current data; The stability of the beam intensity in each section is calculated by the following specific formula: in, Indicates The stability of the beam intensity; Indicates Standard deviation of the segment beam intensity; Indicates the number of beam intensities in each beam intensity segment; Indicates The beam intensity of the first beam intensity value; Indicates The maximum beam intensity value among the segment beam intensities; Indicates The minimum beam intensity value in the segment beam intensity; represents the absolute value function; represents an exponential function with a natural constant as base; The dark current data is processed in the same segmentation manner, and the stability of each segment of the dark current data is obtained.
3. A method for monitoring dark current derived from deflection of a medical cyclotron according to claim 1, characterized in that: The method of obtaining the slopes of two stability straight lines of beam intensity and dark current and two stability curves of beam intensity and dark current according to the stability of beam intensity and dark current data includes the following specific steps: The order of the segments is taken as the horizontal coordinate, and the stability of each segment of the beam intensity and each segment of the dark current data is taken as the vertical coordinate. The beam intensity and dark current data of all segments are plotted as scatter plots, and the stability of the beam intensity and dark current data in the scatter plots are fitted with straight lines by the least square method to obtain two stability straight lines and their slopes for the beam intensity and dark current data. The stability of the beam intensity and dark current data in each segment of the scatter plot are connected respectively to obtain two stability curves of the beam intensity and dark current data.
4. A method for monitoring dark current derived from deflection of a medical cyclotron according to claim 1, characterized in that: The step of obtaining the interaction degree between beam intensity and dark current data includes the following specific steps: in, Indicates the degree of interaction between beam intensity and dark current data; The slope of the stability line representing the beam intensity; The slope of the stability line representing the dark current data; represents the stability curve representing the beam intensity; shows the stability curve representing the dark current data; Indicates calculating the DTW distance between two curves; represents the absolute value function; Represents the sigmoid function; Represents an exponential function with a natural constant as its base.
5. The method for monitoring dark current induced by deflection of a medical cyclotron according to claim 1, characterized in that: The step of obtaining predicted intensities of a plurality of beam intensities according to the time series distribution of beam intensities includes the following specific steps: The time series of beam intensity is analyzed by Arima algorithm to obtain the predicted intensity of several beam intensities.
6. A method for monitoring dark current derived from deflection of a medical cyclotron according to claim 1, characterized in that: The step of obtaining the predicted variation degree of each beam intensity segment includes the following specific steps: in, Indicates The predicted degree of variation of the beam intensity in the segment; Indicates The stability of the beam intensity; Indicates The number of predicted intensities in the segment beam intensity; Indicates The beam intensity in the first The prediction strength; represents the mean of all beam intensity values; represents the absolute value function; Represents an exponential function with a natural constant as its base.
7. A method for monitoring dark current derived from deflection of a medical cyclotron according to claim 1, characterized in that: The method of obtaining the predicted change trend of each segment of dark current data according to the predicted change degree of each segment of beam intensity and the interaction degree between beam intensity and dark current data includes the following specific steps: Calculate the interaction degree between beam intensity and dark current data and the The product of the predicted variation degree of the beam intensity of the first segment is recorded as Predicted change trend of dark current data in the segment.
8. The method for monitoring dark current induced by deflection of a medical cyclotron according to claim 1, characterized in that: The method of obtaining the adjusted sampling frequency of each segment of dark current data according to the initial sampling frequency and the predicted change trend of each segment of dark current data includes the following specific steps: Calculate 1 and The product of the initial sampling frequency and the predicted change trend of the dark current data of the first segment is recorded as The dark current data of this segment has an adjusted sampling frequency.
9. A method for monitoring dark current derived from deflection of a medical cyclotron according to claim 1, characterized in that: The dark current is dynamically collected according to the sampling frequency adjusted for each segment of dark current data, and the specific steps include the following: During the normal operation of the medical cyclotron, the dark current data is collected using the sampling frequency adjusted for the latest dark current data, and the adjusted sampling frequency for the next dark current data is obtained, and the data is collected backwards according to the adjusted sampling frequency, and so on, until the cyclotron is completed and the dark current data collection is completed.
10. A dark current monitoring device for deflection of a medical cyclotron, characterized in that: The device comprises: A data acquisition module, a data processing module and a data detection module; wherein the data acquisition module is used to collect beam intensity and dark current data in a medical cyclotron, the data processing module implements the steps of a dark current monitoring method induced by deflection of a medical cyclotron as described in any one of claims 1 to 9 by calling a computer program to obtain the adjusted sampling frequency of each segment of dark current data, the data detection module dynamically collects dark current according to the adjusted sampling frequency of each segment of dark current data, and detects significant changes in the collected dark current data.