Radio frequency source adjustable radio frequency tumor hyperthermia system

Abstract

The present application relates to the technical field of radio frequency hyperthermia equipment control, in particular to a radio frequency tumor hyperthermia system with adjustable radio frequency source, which comprises: a plurality of radio frequency sources, a radio frequency source controller; a radio frequency control module, which is used for reducing the frequency of abnormal radio frequency source when the abnormal radio frequency source appears, changing the frequency of normal radio frequency source according to the heat loss amount generated by the abnormal radio frequency source after the frequency is reduced and the distribution ratio, reducing the frequency of abnormal radio frequency source again when the abnormal radio frequency source appears again, adjusting the distribution ratio according to the temperature change of normal radio frequency source after the frequency is changed in the historical time, and changing the frequency of normal radio frequency source according to the heat loss amount generated by the abnormal radio frequency source after the frequency is reduced again and the adjusted distribution ratio. The present application can ensure that the deep part of the body tissue reaches sufficient temperature while avoiding the phenomenon of fat overheating, and adapt to the specific hyperthermia situation of the patient.

Description

Technical Field

[0001] This invention relates to the field of radiofrequency hyperthermia equipment control technology, specifically to a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source. Background Technology

[0002] Current hyperthermia devices use oscillation frequencies of 8MHz, 13.56MHz, 27.12MHz, and 40.68MHz, with two-electrode output and capacitive electric fields. Based on the principle of heat generation in the human body from high-frequency electromagnetic waves, a drawback is that during clinical treatment, the patient's surface temperature becomes too high to tolerate. To reduce capacitive reactance and prevent excessive heat generation from the skin and fat, cold water circulation can be used to couple and lower the surface temperature. However, to achieve sufficient deep tissue temperature, fat overheating still occurs, and power loss is significant. Furthermore, this method cannot completely solve the problem of excessively high surface temperatures preventing the attainment of the required temperature for deep lesions. Summary of the Invention

[0003] To address the above problems, the present invention provides a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source.

[0004] The radiofrequency tumor hyperthermia system with adjustable radiofrequency source of the present invention adopts the following technical solution:

[0005] One embodiment of the present invention provides a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source, comprising: a radiofrequency source, a body temperature sensor, and a radiofrequency source controller;

[0006] The number of radio frequency sources is greater than or equal to 2, and the body temperature sensor is installed at the location of each radio frequency source.

[0007] The RF source controller includes the following modules:

[0008] The body temperature detection module is used to collect and record the temperature of each radiofrequency source location at each moment during hyperthermia, and to determine in real time whether the temperature exceeds the upper limit of the tolerable temperature. Radiofrequency sources at locations that exceed the upper limit of the tolerable temperature are recorded as abnormal radiofrequency sources, while radiofrequency sources at locations that do not exceed the upper limit of the tolerable temperature are recorded as normal radiofrequency sources.

[0009] The radio frequency control module is used to reduce the frequency of the abnormal radio frequency source when an abnormal radio frequency source occurs, and to change the frequency of the normal radio frequency source according to the amount of heat loss and the distribution ratio generated by the abnormal radio frequency source after the frequency reduction.

[0010] When an abnormal radio frequency source reappears, the frequency of the abnormal radio frequency source is reduced again. The allocation ratio is adjusted according to the temperature change of the normal radio frequency source after changing its frequency in historical time. The frequency of the normal radio frequency source is changed according to the heat loss generated by the abnormal radio frequency source after reducing its frequency again and the adjusted allocation ratio.

[0011] The specific method for obtaining the heat loss is as follows:

[0012] The amount of heat loss is estimated based on the frequency of the abnormal radio frequency source after frequency reduction and the location of the tumor.

[0013] The steps involved in changing the frequency of the normal radio frequency source are as follows:

[0014] The heat loss is allocated to each normal RF source according to the allocation characteristics to obtain the frequency that each normal RF source needs to increase; the frequency of each normal RF source is changed according to the frequency that needs to be increased; the allocation characteristics include the allocation ratio and the adjusted allocation ratio, and each normal RF source corresponds to one allocation characteristic.

[0015] Preferably, the step of estimating the heat loss based on the frequency of the abnormal radio frequency source after frequency reduction and the location of the tumor includes the following steps:

[0016] The heat loss was estimated by substituting the frequency of the abnormal radiofrequency source after frequency reduction and the location of the tumor into the frequency-thermal model.

[0017] Preferably, the specific steps for allocating the heat loss to each normal RF source according to the allocation characteristics to obtain the frequency increase required for each normal RF source are as follows:

[0018] The product of the heat loss and the allocation characteristics of each normal radio frequency source is recorded as the heat loss allocated to each normal radio frequency source. The allocated heat loss and the location of the tumor are substituted into the frequency-thermal model to obtain the frequency that each normal radio frequency source needs to increase.

[0019] Preferably, the specific steps of adjusting the allocation ratio based on the temperature change after the normal radio frequency source changes its frequency in historical time periods are as follows:

[0020] The heat loss generated by the abnormal radio frequency source after the frequency is reduced again is denoted as P. The heat loss P is allocated to each normal radio frequency source according to the allocation ratio to obtain the frequency that each normal radio frequency source needs to increase, denoted as L1.

[0021] For each normal RF source, the frequency change amount at each historical moment is used to obtain the adjusted allocation ratio of each normal RF source based on the difference between L1 and the frequency change amount at each frequency change, as well as the temperature change after each frequency change.

[0022] Preferably, the specific steps for obtaining the adjusted allocation ratio of each normal radio frequency source based on the difference between L1 and the frequency change amount at each frequency change, as well as the temperature change after each frequency change, are as follows:

[0023] Several frequency changes with the smallest difference from L1 are obtained and denoted as reference frequency changes. The temperature change rate is obtained based on the temperature change after each frequency change. Each reference frequency change corresponds to a temperature change rate. The adjusted allocation ratio of each normal RF source is obtained based on the temperature change rates corresponding to all reference frequency changes. The adjusted allocation ratio is negatively correlated with the temperature change rate.

[0024] Preferably, the specific steps for obtaining the frequency-heat model are as follows:

[0025] In each radiofrequency tumor hyperthermia session in history, the tumor location, the location of each radiofrequency source, and the average frequency of each radiofrequency source throughout the entire hyperthermia process were recorded and used as a sample; the reciprocal of the tumor ablation time in each radiofrequency tumor hyperthermia session was used as the sample label.

[0026] The frequency-thermal model takes as input the tumor location, radiofrequency source location, and frequency of each radiofrequency source in each sample, and outputs the heat at the tumor location.

[0027] The frequency-thermal model was trained using samples and labels obtained from all historical radiofrequency tumor hyperthermia procedures.

[0028] Preferably, the rate of temperature change is the absolute value of the average slope of the temperature over time after each change in frequency.

[0029] Preferably, the specific steps for obtaining the adjusted allocation ratio for each normal RF source based on the temperature change rate corresponding to all reference frequency changes are as follows:

[0030] The mean of the temperature change rate corresponding to all reference frequency changes is used as the allocation index w for each normal RF source. The allocation index w of the normal RF source is linearly normalized to obtain w1. The allocation ratio of each normal RF source is denoted as a. The adjusted allocation ratio of each normal RF source is negatively correlated with w1 and positively correlated with a.

[0031] Preferably, it also includes a tumor localization module for obtaining the tumor location based on the MRI equipment.

[0032] Preferably, each radio frequency source includes two electrodes, and a body temperature sensor is installed at each electrode position. When the temperature value output by either temperature sensor at the two electrode positions exceeds the upper limit of the tolerance temperature, the radio frequency source corresponding to the two electrodes is recorded as an abnormal radio frequency source; when the temperature values ​​output by all temperature sensors at the two electrode positions do not exceed the upper limit of the tolerance temperature, the radio frequency source corresponding to the two electrodes is recorded as a normal radio frequency source.

[0033] The beneficial effects of the technical solution of this invention are as follows: The invention uses at least two radiofrequency sources, ensuring that the required temperature is reached at deep lesion sites. Furthermore, the radiofrequency control module of this invention reduces the frequency of an abnormal radiofrequency source when one occurs, and adjusts the frequency of the normal radiofrequency source based on the heat loss and distribution ratio generated by the abnormal source after frequency reduction; this ensures that the heat loss is distributed among the normal radiofrequency sources, preventing sustained high temperatures at any one source location. Simultaneously, the distribution ratio is adjusted based on temperature changes after frequency changes at the normal radiofrequency source over historical periods, dynamically adjusting the ratio in conjunction with the physiological conditions of specific tissue sites during the operation of the normal radiofrequency sources to adapt to the specific conditions of different patient sites.

[0034] In summary, this invention ensures that the deep lesion sites in the human body reach the required temperature, while reasonably changing the frequency of the radio frequency source to adapt to the different hyperthermia conditions of the patient's body parts, thus avoiding overheating of fat and power loss. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the framework structure of a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source, provided in one embodiment of the present invention. Detailed Implementation

[0037] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] The following description, in conjunction with the accompanying drawings, details a specific scheme for a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source provided by the present invention.

[0040] Example 1:

[0041] Please see Figure 1 The diagram shows a structure of a radiofrequency tumor hyperthermia system with an adjustable radiofrequency source according to Embodiment 1 of the present invention. The system includes a radiofrequency source, a body temperature sensor, a radiofrequency source controller, and a tumor localization module.

[0042] The number of radio frequency sources is greater than or equal to 2. This embodiment uses 4 radio frequency sources as an example for description.

[0043] In this embodiment, multiple radio frequency sources jointly emit high-frequency electromagnetic waves to perform thermotherapy ablation on tumors, effectively solving the problems of overheating of fat and insufficient heating energy in the deep parts of the body.

[0044] Temperature sensors are installed at the location of each radio frequency source to collect the temperature generated on the body surface by each radio frequency source during radio frequency hyperthermia.

[0045] To avoid excessive heat generation on the skin and fat during hyperthermia from multiple radiofrequency sources, and to prevent adjacent electrode plates from generating circuits due to excessively similar frequencies, which would result in heat generation on the human body surface and failure to reach deeper tissues, a radiofrequency source controller is needed to automatically control multiple radiofrequency sources. This allows multiple radiofrequency sources to work together to ensure heat reduction during tumor hyperthermia while avoiding excessive heat generation on the human body surface.

[0046] The tumor localization module is used to obtain the location of the tumor based on MRI or CT equipment.

[0047] In this embodiment, the radio frequency source controller includes two parts: a body temperature detection module and a radio frequency control module.

[0048] The body temperature detection module is used to collect and record the temperature of each radiofrequency source location at each moment during hyperthermia, and to determine in real time whether the temperature exceeds the upper limit of the tolerable temperature. Radiofrequency sources at locations exceeding the upper limit of the tolerable temperature are recorded as abnormal radiofrequency sources, while those at locations not exceeding the upper limit of the tolerable temperature are recorded as normal radiofrequency sources. In this embodiment, the upper limit of the tolerable temperature is set to 41 degrees Celsius. Other values ​​may be set in other embodiments, and this embodiment does not impose specific limitations.

[0049] It should be noted that each radio frequency source contains two electrodes, and a body temperature sensor is installed at each electrode position. If the temperature value output by either temperature sensor at the two electrode positions exceeds the upper limit of the tolerance temperature, the radio frequency source corresponding to the two electrodes is recorded as an abnormal radio frequency source. When the temperature values ​​output by all temperature sensors at the two electrode positions do not exceed the upper limit of the tolerance temperature, the radio frequency source corresponding to the two electrodes is recorded as a normal radio frequency source.

[0050] The radio frequency control module is used to reduce the frequency of the abnormal radio frequency source when an abnormal radio frequency source occurs, and to change the frequency of the normal radio frequency source according to the amount of heat loss and the allocation ratio generated by the abnormal radio frequency source after the frequency reduction.

[0051] When an abnormal radio frequency source reappears, the frequency of the abnormal radio frequency source is reduced again. The allocation ratio is adjusted according to the temperature change of the normal radio frequency source after changing its frequency in historical time. The frequency of the normal radio frequency source is changed according to the heat loss generated by the abnormal radio frequency source after reducing its frequency again and the adjusted allocation ratio.

[0052] In the aforementioned radiofrequency control module, whenever an abnormal radiofrequency source is detected, its frequency is reduced to prevent excessively high skin temperature. When the frequency decreases, heat loss occurs at the tumor site, necessitating an increase in the power of the normal radiofrequency source to compensate for the lost heat. To reasonably increase the frequency of the normal radiofrequency source, the frequency needs to be adjusted proportionally based on the temperature change during frequency changes for each normal radiofrequency source. Considering the differences in skin and adipose tissue across different body parts, and the varying heat recording patterns of radiofrequency sources at different frequencies, the frequency adjustment ratio for each normal radiofrequency source in this embodiment is different. This allows for better utilization of different body parts and radiofrequency sources at different frequencies.

[0053] For example, when the abnormal radio frequency source occurs for the i-th time, according to the amount of heat loss and allocation ratio Change the frequency of the normal radio frequency source;

[0054] When an abnormal RF source occurs for the (i+1)th time, the amount of heat loss is determined according to... and allocation ratio Change the frequency of the normal radio frequency source; among which Not equal to ; Compared to In other words, It is about adjusting the allocation ratio. The adjusted allocation ratio is referred to as the adjusted allocation ratio.

[0055] When an abnormal RF source occurs for the i+2th time, the amount of heat loss is considered. and allocation ratio Change the frequency of the normal radio frequency source, among which Not equal to ; Compared to In other words, It is about adjusting the allocation ratio. The adjusted allocation ratio is referred to as the adjusted allocation ratio.

[0056] Therefore, the allocation ratio and the adjusted allocation ratio are relative to each of two consecutive occurrences of abnormal radio frequency sources.

[0057] During this process, the allocation ratio is dynamically adjusted in real time based on the temperature changes of the specific parts of the patient and the working status of the radiofrequency source.

[0058] In this embodiment, the specific method for obtaining the heat loss is as follows:

[0059] The amount of heat loss is estimated based on the frequency of the abnormal radiofrequency source after frequency reduction and the location of the tumor.

[0060] For example, when an abnormal radio frequency source occurs for the i-th time, the frequency of the abnormal radio frequency source is reduced, and the frequency of the abnormal radio frequency source after the reduction is denoted as . ,according to Estimating heat loss based on tumor location ;

[0061] When an abnormal radio frequency source occurs for the (i+1)th time, the frequency of the abnormal radio frequency source is reduced. The frequency of the abnormal radio frequency source after the reduction is denoted as . ,according to Estimating heat loss based on tumor location ;

[0062] As an example, in this embodiment, the frequency of the abnormal radio frequency source is reduced by 5% each time an abnormal radio frequency source occurs. Other embodiments may reduce the frequency by other values, but this embodiment does not impose any specific limitations.

[0063] If multiple abnormal radiofrequency sources occur simultaneously, the frequency of each abnormal radiofrequency source is reduced by 5%. At this time, the amount of heat loss is estimated based on the frequencies of all abnormal radiofrequency sources after the frequency reduction and the location of the tumor.

[0064] The estimation of heat loss is based on the frequency of the abnormal radiofrequency source after frequency reduction and the location of the tumor, specifically including:

[0065] First, a frequency-thermal model is obtained. The inputs to the frequency-thermal model are the tumor location, the location of each radiofrequency source, and the frequency of each radiofrequency source. The output is heat. Then, the frequency and location of the abnormal radiofrequency sources after frequency reduction, and the location of the tumor are substituted into the frequency-thermal model to obtain the heat loss.

[0066] In this embodiment, changing the frequency of the normal radio frequency source includes the following steps:

[0067] The heat loss is allocated to each normal RF source according to the allocation characteristics to obtain the frequency increase required for each normal RF source; the frequency of each normal RF source is changed according to the required increase frequency; the allocation characteristics include the above allocation ratio and the adjusted allocation ratio.

[0068] For example, when the abnormal radio frequency source occurs for the i-th time, the heat loss will be... According to the allocation ratio The frequency of each normal radio frequency source is assigned to each normal radio frequency source, and the frequency that each normal radio frequency source needs to increase is obtained; that is, when an abnormal radio frequency source appears for the i-th time, the frequency of each normal radio frequency source is increased.

[0069] When the (i+1)th abnormal RF source occurs, the heat loss will be... According to the allocation ratio The frequency of each normal radio frequency source is assigned to each normal radio frequency source, and the frequency that each normal radio frequency source needs to increase is obtained; that is, when an abnormal radio frequency source appears for the (i+1)th time, the frequency of each normal radio frequency source is increased.

[0070] It should be noted that each normal RF source corresponds to a specific allocation characteristic. For example, if an abnormal RF source occurs for the i-th time, and there are 3 normal RF sources, when allocated according to a ratio of 0.1:0.8:0.1, the allocation ratio of the 3 normal RF sources is as follows: The values ​​are 0.1, 0.8, and 0.1 respectively.

[0071] It should be noted that the normal radio frequency source when the abnormal radio frequency source appears for the (i+1)th time is not necessarily the normal radio frequency source when the abnormal radio frequency source appears for the ith time; a normal radio frequency source needs to be reacquired in real time each time an abnormal radio frequency source appears.

[0072] Before hyperthermia treatment, all radiofrequency sources are considered normal and their initial allocation ratio is the same. For example, if there are four normal radiofrequency sources before hyperthermia treatment, the allocation ratio of the four normal radiofrequency sources is set to be the same, that is, the allocation ratio is 0.25:0.25:0.25:0.25. However, if abnormal radiofrequency sources occur during subsequent treatments (such as the first, second, or third treatment), the allocation ratio needs to be adjusted according to the temperature changes after the normal radiofrequency sources changed their frequencies in historical time periods.

[0073] In summary, the heat loss is distributed among the normal radiofrequency sources according to the allocation ratio, preventing any single radiofrequency source location from experiencing sustained high temperatures. Furthermore, the allocation ratio is adjusted based on temperature changes in the normal radiofrequency sources over historical periods after frequency modifications. This dynamic adjustment, combined with the physiological conditions of specific tissue sites during the operation of the normal radiofrequency sources, adapts to the specific circumstances of different patient locations.

[0074] As an example, the heat loss is allocated to each normal RF source according to the allocation characteristics to obtain the frequency increase required for each normal RF source. The steps include:

[0075] The product of the heat loss and the allocation characteristics of each normal RF source is recorded as the heat loss allocated to each normal RF source.

[0076] For example, when the abnormal radio frequency source occurs for the i-th time, the heat loss is... According to the allocation ratio The data is allocated to each of the three normal radio frequency sources, with the following allocation ratio: Then the heat loss of the first normal RF source is The heat loss of the second normal RF source is The heat loss of the third normal RF source is .

[0077] For example, when an abnormal RF source occurs for the (i+1)th time, the heat loss... According to the adjusted allocation ratio Assigned to each normal radio frequency source.

[0078] The required increase in frequency for each normal radiofrequency source is determined based on the heat loss allocated to each normal radiofrequency source, the location of the tumor, and the frequency-thermal model of the location of each normal radiofrequency source.

[0079] Example 2:

[0080] In this embodiment, as an optional example, adjusting the allocation ratio based on the temperature change of a normal radio frequency source after changing its frequency at historical times includes the following method:

[0081] The average temperature of a normal radio frequency source after changing its frequency at historical moments is denoted as M. The larger M is, the more likely the normal radio frequency source is to accumulate temperature. In this case, it is necessary to reduce the allocation ratio of the normal radio frequency source. Therefore, the reciprocal of the average value of all normal radio frequency sources is normalized to obtain the adjusted allocation ratio of each normal radio frequency source.

[0082] The average temperature after changing the frequency refers to the average temperature over a period of time between each frequency change and the next frequency change.

[0083] In this example, the computational load is low, but it does not take into account whether the allocation ratio was appropriate when the abnormal heat source occurred last time. Instead, it directly redistributes the ratio without further adjusting the allocation ratio according to the patient's specific situation. This results in an inefficient process of finding a suitable allocation ratio to adapt to the heat therapy situation of different parts of the patient.

[0084] In this embodiment, as a preferred example, adjusting the allocation ratio based on the temperature change of a normal radio frequency source after changing its frequency at historical times includes the following method:

[0085] Assuming that the heat loss occurs for the i-th time due to an abnormal radio frequency source, According to the allocation ratio The frequency required to be increased for each normal radio frequency source is determined by allocating the frequency to each normal source; that is, when an abnormal radio frequency source appears for the i-th time, it is determined according to the allocation ratio. To allocate the required additional frequency to each normal radio frequency source.

[0086] When an abnormal radio frequency source occurs for the (i+1)th time, the allocation ratio needs to be adjusted. Adjustments were made to adapt to the patient's real-time physical condition, and the adjusted allocation ratio was expressed as follows: .

[0087] For the allocation ratio The specific steps for making the adjustments are as follows:

[0088] The heat loss generated by the abnormal radio frequency source when the (i+1)th abnormal radio frequency source occurs, after the (i+1)th frequency reduction, is denoted as . ;

[0089] First, consider the heat loss. According to the allocation ratio The frequency L1 required to be increased for each normal radio frequency source is obtained by allocating the frequency to each normal radio frequency source. The specific process has been described in Example 1 and will not be repeated here.

[0090] It should be noted that the normal radio frequency sources here refer to the normal radio frequency sources when the abnormal radio frequency source appears for the (i+1)th time. These normal radio frequency sources may have been normal radio frequency sources or abnormal radio frequency sources in history.

[0091] The frequency L1 that each normal RF source needs to increase at this time represents the frequency that needs to be increased when allocating using the previous allocation ratio, not the frequency that needs to be increased when an abnormal RF source occurs this time.

[0092] For each normal RF source, the frequency change amount at each historical moment is used to obtain the adjusted allocation ratio of each normal RF source based on the difference between L1 and the frequency change amount at each frequency change, as well as the temperature change after each frequency change; wherein changing the frequency includes increasing the frequency and decreasing the frequency.

[0093] The temperature change after each frequency change describes the temperature characteristics of the body tissue at the location of the normal radiofrequency source during its historical operation under different frequency changes. For example, the characteristics of temperature rising or falling slowly or rapidly. This characteristic is used to adjust the previous allocation ratio so that the current allocation ratio is more adapted to the specific situation of the patient's body tissue, such as avoiding a rapid increase in temperature.

[0094] The difference between L1 and the frequency change amount at each frequency change describes: the heat loss amount when the abnormal radio frequency source occurs for the current time (i.e., the i+1th time) according to the distribution ratio when the abnormal radio frequency source occurs for the previous time (i.e., the ith time). When allocating, the magnitude of the resulting increase in frequency compared to the historical frequency change is considered. Different magnitudes of this difference correspond to different temperature characteristics, which influence the allocation ratio. The adjustment range also varies.

[0095] Therefore, this embodiment adjusts the previous allocation ratio based on the differences in frequency change and the temperature characteristics of temperature change. This can guarantee the adjusted allocation ratio. It is more adapted to the specific conditions of the patient's body tissues.

[0096] As an example, the method for obtaining the adjusted allocation ratio of each normal RF source based on the difference between L1 and the frequency change amount at each frequency change, as well as the temperature change after each frequency change, includes:

[0097] The N frequency changes (excluding L1) that have the smallest difference from L1 are obtained and are denoted as reference frequency changes. The temperature change rate is obtained based on the temperature change after each frequency change. Each reference frequency change corresponds to a temperature change rate. The adjusted allocation ratio of each normal RF source is obtained based on the temperature change rates corresponding to all reference frequency changes. The adjusted allocation ratio is negatively correlated with the temperature change rate.

[0098] This process also applies to each normal radio frequency source when an abnormal radio frequency source occurs for the (i+1)th time.

[0099] This embodiment uses N=5 as an example. Other embodiments can be set to other values. This embodiment does not impose specific limitations. When the frequency change with the smallest difference from L1 is less than N, then the number of frequency changes with the smallest difference is considered. The difference mentioned here refers to the absolute value of the difference.

[0100] The aforementioned changes in reference frequency are relatively similar to L1; therefore, the temperature characteristics (i.e., the rate of temperature change) of the patient's body tissues corresponding to the changes in reference frequency are more likely to reflect the allocation ratio. Whether the increased frequency L1 is appropriate, and thus reflects the allocation ratio. The adjustment range.

[0101] As an example, the method for obtaining the adjusted allocation ratio for each normal RF source based on the temperature change rate corresponding to all reference frequency changes includes:

[0102] The rate of temperature change is the absolute value of the average slope of temperature over time after each frequency change, indicating the magnitude of the effect of frequency change on temperature. The larger the mean of the rate of temperature change, the more likely the frequency change will cause a larger temperature change; the smaller the mean of the rate of temperature change, the more likely the frequency change will cause a smaller temperature change.

[0103] It should be noted that the average slope of temperature over time after each frequency change refers to the average slope of temperature over time during the period between each frequency change and the next frequency change.

[0104] The average of the temperature change rates corresponding to all reference frequency changes is denoted as k1. k1 is used as the allocation index w for each normal RF source. The larger w is, the stronger the allocation ratio will be, as in the previous allocation. The more the frequency L1 is increased, the more likely it is to cause a significant temperature change; therefore, it is necessary to reduce it more when an abnormal RF source is first detected. This avoids the normal radio frequency source distributing too much frequency. The smaller w is, the more likely the frequency distribution will follow the previous allocation ratio. The more frequently L1 is increased, the less likely it is to cause a significant temperature change; therefore, it is currently necessary to increase the frequency. This allows the normal radio frequency source to distribute more frequencies.

[0105] The allocation index w of all normal radio frequency sources is linearly normalized to obtain the normalized allocation index w1, which falls within the range of 0 to 1. Based on the allocation ratio of each normal radio frequency source... And the adjusted allocation ratio for each normal RF source is obtained from the normalized allocation index w1. The formula is: .

[0106] In other embodiments, it can be made .

[0107] This embodiment only requires and A negative correlation is acceptable; no specific calculation model is required.

[0108] It should be noted that, in order to ensure that the sum of the adjusted allocation ratios of all normal RF sources equals 1, it is also necessary to adjust the adjusted allocation ratio of each normal RF source. Normalization is performed again, this time using the Softmax function normalization method. The Softmax function is a well-known technique, and will not be described in detail in this embodiment.

[0109] Example 3:

[0110] As an example, the method for constructing a frequency-heat model is as follows:

[0111] In each radiofrequency tumor hyperthermia session in history, the tumor location, the location of each radiofrequency source, and the average frequency of each radiofrequency source throughout the entire hyperthermia process were recorded and used as a sample; the heat at the tumor location during each radiofrequency tumor hyperthermia session was used as a label for the sample.

[0112] Therefore, all radiofrequency tumor hyperthermia procedures in history correspond to multiple samples and their labels.

[0113] Considering that the heat at the tumor location cannot be directly obtained, but the heat at the tumor location is negatively correlated with the tumor ablation time, that is, the higher the heat, the shorter the tumor ablation time, this embodiment uses the reciprocal of the tumor ablation time as the label for each sample, but it can still be considered that the label can represent the heat at the tumor location.

[0114] The location of the tumor can be obtained by MRI or CT techniques, which will not be described in detail in this embodiment.

[0115] A frequency-thermal model is trained using all samples and labels. The inputs to the model are the tumor location in each sample, the location of each radiofrequency source, and the average frequency of each radiofrequency source during the entire hyperthermia process. The output is the heat at the tumor location. It should be noted that the heat at the tumor location output by the frequency-thermal model is represented by the reciprocal of the tumor ablation time, and it is not necessary to output the true and accurate heat at the tumor location.

[0116] Furthermore, considering that the number of radiofrequency sources used in each hyperthermia process in history may vary, resulting in inconsistent dimensions of the input data for the frequency-thermal model, this embodiment fills the missing dimensions with 0. That is, the location and average frequency of the missing radiofrequency sources are replaced with 0. This is a commonly used sample data preprocessing method, which will not be elaborated on in this embodiment.

[0117] The frequency-heat model in this embodiment is a 5th-order polynomial model containing parameters to be learned. Other embodiments may use a Gaussian mixture model or a fully connected neural network model. During training, the parameters to be learned are updated using the stochastic gradient descent algorithm, and the loss function is the mean squared error loss function. The training methods for both the 5th-order polynomial model and the fully connected neural network model are the same and well-known, and will not be elaborated upon in this embodiment. The 5th-order polynomial model in other embodiments can also obtain the parameters to be learned using the least squares method; the specific process will not be detailed in this embodiment.

[0118] It should be noted that the frequency-thermal model described above is not an accurate model for measuring the frequency domain and heat of a radiofrequency source. This is because, firstly, the body tissue structures of different patients at different locations vary, making it difficult to obtain a simple and accurate frequency-thermal model. Secondly, since tumors are located inside the body, it is impossible to obtain heat data from the tumor location. Considering that the purpose of all embodiments of this invention is to assign frequencies to different radiofrequency sources, the heat loss amount required in this embodiment is only an intermediate variable and is not used for measuring actual physical laws. Therefore, this embodiment uses the above method to construct a frequency-thermal model that can roughly assess the heat loss amount.

[0119] As an example, the heat loss is obtained based on the frequency and location of the abnormal radiofrequency source after frequency reduction, the location of the tumor, and the frequency-thermal model. The methods include:

[0120] The frequency and location of the abnormal radiofrequency source after frequency reduction, the frequency and location of the normal radiofrequency source, and the location of the tumor are substituted into the trained frequency-thermal model, and the model output is denoted as R1.

[0121] The frequency and location of the abnormal radiofrequency source before frequency reduction, the frequency and location of the normal radiofrequency source, and the location of the tumor are substituted into the trained frequency-thermal model, and the model output is denoted as R2.

[0122] R2-R1 represents the heat loss.

[0123] As an example, the frequency increase required for each normal radiofrequency source is determined based on the heat loss allocated to each normal radiofrequency source, the location of the tumor, and a frequency-thermal model of the location of each normal radiofrequency source. The methods include:

[0124] When the abnormal radio frequency source occurs for the i-th time:

[0125] For all radiofrequency sources at this time, including the reduced abnormal radiofrequency sources and normal radiofrequency sources, substitute the frequency and location of all radiofrequency sources and the location of the tumor into the trained frequency-thermal model, and denote the model output as R3;

[0126] Let the heat loss allocated to the j-th normal RF source be denoted as . .

[0127] Let the frequency that the j-th normal RF source needs to increase be denoted as the parameter to be solved. The frequency of the j-th normal radio frequency source is denoted as . ;Will The frequencies of all radiofrequency sources other than the j-th normal radiofrequency source, along with the locations of all radiofrequency sources and the tumor, are substituted into the trained frequency-thermal model to solve for... Make the output of the frequency-heat model equal to .

[0128] The solution The frequency that needs to be increased for the j-th normal RF source can be obtained similarly for the frequencies that need to be increased for other normal RF sources.

[0129] Similarly, when an abnormal radio frequency source appears for the (i+1)th time, the same method is used to obtain the frequency increase required for each normal radio frequency source.

[0130] It should be noted that when the frequency-heat model is a polynomial model, the analytical method of function can be used to solve it. This embodiment uses the stochastic gradient descent method to solve the problem. In other embodiments, when a fully connected neural network is used, stochastic gradient descent can also be used to solve the problem. The stochastic gradient descent method is not only a commonly used and well-known algorithm for training models, but also an optimization algorithm for solving optimal parameters. They are essentially the same, so the specific process of the stochastic gradient descent method will not be described in detail in this embodiment.

[0131] 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 within the protection scope of the present invention.

Claims

1. A radiofrequency tumor hyperthermia system with an adjustable radiofrequency source, characterized in that, The system includes a radio frequency source, a body temperature sensor, and a radio frequency source controller; The number of radio frequency sources is greater than or equal to 2, and the body temperature sensor is installed at the location of each radio frequency source. The RF source controller includes the following modules: The body temperature detection module is used to collect and record the temperature of each radiofrequency source location at each moment during hyperthermia, and to determine in real time whether the temperature exceeds the upper limit of the tolerable temperature. Radiofrequency sources at locations that exceed the upper limit of the tolerable temperature are recorded as abnormal radiofrequency sources, while radiofrequency sources at locations that do not exceed the upper limit of the tolerable temperature are recorded as normal radiofrequency sources. The radio frequency control module is used to reduce the frequency of the abnormal radio frequency source when an abnormal radio frequency source occurs, and to change the frequency of the normal radio frequency source according to the amount of heat loss and the distribution ratio generated by the abnormal radio frequency source after the frequency reduction. When an abnormal radio frequency source reappears, the frequency of the abnormal radio frequency source is reduced again. The allocation ratio is adjusted according to the temperature change of the normal radio frequency source after changing its frequency in historical time. The frequency of the normal radio frequency source is changed according to the heat loss generated by the abnormal radio frequency source after reducing its frequency again and the adjusted allocation ratio. The specific method for obtaining the heat loss is as follows: The amount of heat loss is estimated based on the frequency of the abnormal radio frequency source after frequency reduction and the location of the tumor. The steps involved in changing the frequency of the normal radio frequency source are as follows: The heat loss is allocated to each normal RF source according to the allocation characteristics to obtain the frequency increase required for each normal RF source. The frequency of each normal radio frequency source is changed according to the required increase frequency; the allocation feature includes the allocation ratio and the adjusted allocation ratio, and each normal radio frequency source corresponds to one allocation feature; The specific steps involved in adjusting the allocation ratio based on the temperature change after the normal radio frequency source changes its frequency in historical time periods are as follows: The heat loss generated by the abnormal radio frequency source after the frequency is reduced again is denoted as P. The heat loss P is allocated to each normal radio frequency source according to the allocation ratio to obtain the frequency that each normal radio frequency source needs to increase, denoted as L1. For each normal RF source, the frequency change amount at each time the frequency is changed in the historical time is used to obtain the adjusted allocation ratio of each normal RF source based on the difference between L1 and the frequency change amount at each time the frequency is changed, as well as the temperature change after each frequency change. The specific steps involved in obtaining the adjusted allocation ratio for each normal radio frequency source based on the difference between L1 and the frequency change amount at each frequency change, as well as the temperature change after each frequency change, are as follows: Obtain several frequency changes that have the smallest difference from L1, and denote them as reference frequency changes. Obtain the temperature change rate based on the temperature change after each frequency change. Each reference frequency change corresponds to a temperature change rate. Obtain the adjusted allocation ratio of each normal RF source based on the temperature change rates corresponding to all reference frequency changes. The adjusted allocation ratio is negatively correlated with the rate of temperature change. The specific steps involved in obtaining the adjusted allocation ratio for each normal RF source based on the temperature change rate corresponding to all reference frequency changes are as follows: The mean of the temperature change rate corresponding to all reference frequency changes is used as the allocation index w for each normal RF source. The allocation index w of the normal RF source is linearly normalized to obtain w1. The allocation ratio of each normal RF source is denoted as a. The adjusted allocation ratio of each normal RF source is negatively correlated with w1 and positively correlated with a.

2. The radiofrequency tumor hyperthermia system with adjustable radiofrequency source according to claim 1, characterized in that, The steps for estimating heat loss based on the frequency of the abnormal radio frequency source after frequency reduction and the location of the tumor include: The heat loss was estimated by substituting the frequency of the abnormal radiofrequency source after frequency reduction and the location of the tumor into the frequency-thermal model.

3. The radiofrequency tumor hyperthermia system with an adjustable radiofrequency source according to claim 1, characterized in that, The specific steps involved in allocating the heat loss to each normal RF source according to the allocation characteristics, to obtain the frequency increase required for each normal RF source, are as follows: The product of the heat loss and the allocation characteristics of each normal radio frequency source is recorded as the heat loss allocated to each normal radio frequency source. The allocated heat loss and the location of the tumor are substituted into the frequency-thermal model to obtain the frequency that each normal radio frequency source needs to increase.

4. A radiofrequency tumor hyperthermia system with an adjustable radiofrequency source according to claim 2 or 3, characterized in that, The specific steps for obtaining the frequency-thermal model are as follows: In each radiofrequency tumor hyperthermia session in history, the tumor location, the location of each radiofrequency source, and the average frequency of each radiofrequency source throughout the entire hyperthermia process were recorded and used as a sample; the reciprocal of the tumor ablation time in each radiofrequency tumor hyperthermia session was used as the sample label. The frequency-thermal model takes as input the tumor location, radiofrequency source location, and frequency of each radiofrequency source in each sample, and outputs the heat at the tumor location. The frequency-thermal model was trained using samples and labels obtained from all historical radiofrequency tumor hyperthermia procedures.

5. The radiofrequency tumor hyperthermia system with adjustable radiofrequency source according to claim 1, characterized in that, The rate of temperature change is the absolute value of the average slope of temperature over time after each change in frequency.

6. The radiofrequency tumor hyperthermia system with adjustable radiofrequency source according to claim 1, characterized in that, It also includes a tumor localization module, used to obtain the tumor location based on the MRI equipment.

7. The radiofrequency tumor hyperthermia system with adjustable radiofrequency source according to claim 1, characterized in that, Each radio frequency (RF) source contains two electrodes, with a body temperature sensor installed at each electrode location. If the temperature value output by either temperature sensor at either electrode location exceeds the upper limit of the tolerance temperature, the RF source corresponding to both electrodes is recorded as an abnormal RF source. If the temperature values ​​output by all temperature sensors at both electrode locations do not exceed the upper limit of the tolerance temperature, the RF source corresponding to both electrodes is recorded as a normal RF source.

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