Ultrasound dose parameter determination method and ultrasound treatment system

Abstract

The application provides an ultrasonic dose parameter determination method and an ultrasonic treatment system, wherein the ultrasonic dose parameter determination method comprises the following steps: detecting the tissue type and the corresponding tissue thickness between the ultrasonic treatment head and a treatment point; determining the temperature rise required for treatment according to the tissue type at the treatment point; presetting a first treatment duration; calculating the output power of the ultrasonic treatment head according to the tissue type, the tissue thickness, the temperature rise, the first treatment duration and an estimated function fitted in advance; and the estimated function represents the relationship between the output power of the ultrasonic treatment head and the tissue type, the tissue thickness, the temperature rise and the first treatment duration. The estimated result obtained by the embodiment of the application is obtained on the basis of the actual detection result of the tissue to be treated, so that the estimated result can be adaptively adjusted according to the actual situation of the tissue to be treated, thereby making the estimated result more in line with the actual treatment requirements, and meanwhile, the ultrasonic dose can be quickly estimated.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic therapy equipment technology, specifically relating to a method for determining ultrasonic dosage parameters and an ultrasonic therapy system. Background Technology

[0002] Currently, High-Intensity Focused Ultrasound (HIFU) is widely used for treating solid organs from outside the body due to its advantages such as non-invasiveness and precision. For example, it can be used to treat uterine fibroids, liver tumors, osteosarcoma, and pancreatic cancer. Specifically, the HIFU process involves focusing low-intensity ultrasound waves from outside the body onto a target area under the guidance of medical imaging. This causes the target tissue in the target area to rapidly heat up, leading to coagulative necrosis without damaging surrounding normal tissue.

[0003] Effective preoperative ultrasound dosage assessment and administration are crucial for improving the safety and efficacy of focused ultrasound (FUS). However, the dosage administration during clinical FUS treatment largely relies on the physician's experience, which can easily lead to undertreatment or overtreatment, resulting in poor treatment outcomes, increased risk of complications, and hindering postoperative recovery. Some related technologies use physical simulations to calculate the distribution of the ultrasound field and the focal intensity, and then further calculate the required dosage parameters. However, these simulations are computationally intensive, and the results are not adapted to the constantly changing tissue being treated, leading to inaccurate dosage parameters. Summary of the Invention

[0004] The present invention aims to solve the problems of difficulty in determining ultrasound dosage and low accuracy in predicting ultrasound dosage in existing ultrasound therapy, and proposes a method for determining ultrasound dosage parameters and an ultrasound therapy system.

[0005] To achieve the above technical objectives, embodiments of the present invention provide a method for determining ultrasound dosage parameters, comprising:

[0006] The tissue type and corresponding tissue thickness between the ultrasonic treatment head and the treatment point are detected; the required temperature rise for treatment is determined based on the tissue type at the treatment point.

[0007] Preset the first treatment duration;

[0008] The output power of the ultrasonic treatment head is calculated based on the tissue type, the tissue thickness, the temperature rise, the first treatment duration, and a pre-fitted estimation function; the estimation function represents the relationship between the output power of the ultrasonic treatment head and the tissue type, the tissue thickness, the temperature rise, and the first treatment duration.

[0009] Optionally, the estimation function includes an ultrasound attenuation function, a tissue heat conversion function, and a heat dissipation function;

[0010] Wherein, the ultrasound attenuation function represents the relationship between the focal power of the ultrasound signal at the focal point and the output power of the ultrasound treatment head in a specified type of tissue; the tissue heat transfer function represents the relationship between the focal power and the temperature rise of the tissue in a specified type of tissue; and the heat dissipation function represents the heat dissipation capacity of blood flow.

[0011] Optionally, after calculating the output power of the ultrasonic treatment head, the method further includes:

[0012] Determine whether the calculated output power exceeds a preset power safety threshold; if so, adjust the first treatment duration to reduce the subsequently calculated output power to within the power safety threshold; if not, send the calculated output power to the ultrasound treatment head.

[0013] Optionally, the method further includes a step of pre-fitting the ultrasonic attenuation function, which specifically includes:

[0014] For various types of tissues, ultrasound signals with specified output power are radiated onto the tissues at multiple different focal lengths through simulation. The simulated focal power data set is obtained by acquiring multiple simulated focal lengths and multiple simulated focal power data corresponding to the multiple focal lengths.

[0015] Based on the specified output power, multiple focal lengths, and the simulated focal power dataset, a single attenuation coefficient function of the tissue is fitted; wherein, the single attenuation coefficient function represents the relationship between the focal length and the power attenuation ratio of the ultrasound signal in the tissue;

[0016] After the step of detecting the tissue type and corresponding tissue thickness between the ultrasonic treatment head and the treatment point, the corresponding single attenuation coefficient function is selected according to the detected tissue type, and the corresponding single attenuation coefficient is calculated according to the corresponding single attenuation coefficient function and the detected tissue thickness.

[0017] The attenuation coefficient is calculated based on the sum of all the individual attenuation coefficients, and the attenuation coefficient is used as the coefficient of the ultrasonic attenuation function to obtain the ultrasonic attenuation function.

[0018] Optionally, the step of calculating the ultrasonic attenuation function further includes:

[0019] Acquire a specified type of tissue and control the ultrasound treatment head to output a verification ultrasound signal;

[0020] The temperature rise of the tissue located at the focal point is detected, and the corresponding verification focal power is calculated based on the temperature rise.

[0021] Find the corresponding simulated focus power value in the simulated focus power dataset corresponding to the organization, and calculate the difference between the verification focus power and the corresponding simulated focus power;

[0022] Determine whether the difference exceeds the preset calibration range; if not, continue with the step of fitting the single attenuation coefficient function of the tissue; if so, reacquire the simulation focal power dataset.

[0023] Optionally, the method further includes a step of fitting the tissue heat transfer function, which specifically includes:

[0024] The ultrasonic treatment head is controlled to emit ultrasonic signals to various types of tissues with a specified focal power and duration; the corresponding tissue density is obtained, and the focal volume of the ultrasonic treatment head is obtained.

[0025] Detect the temperature rise of the corresponding tissue;

[0026] The accumulated ultrasonic energy at the focal point is calculated based on the specified focal power and the specified duration.

[0027] A heat conversion coefficient is fitted based on the ultrasound energy, the focal volume, the tissue density, and the temperature rise, and the heat conversion coefficient is used as a coefficient in the tissue heat conversion function to obtain the tissue heat conversion function.

[0028] Optionally, the step of fitting the tissue heat transfer function further includes:

[0029] Magnetic resonance imaging was performed on various types of tissues, and the corresponding T2 signals in the magnetic resonance images were acquired respectively.

[0030] Based on the thermal conversion coefficients and T2 signals corresponding to various different types of the tissues, a functional relationship between the T2 signal and the thermal conversion coefficients is fitted.

[0031] Optionally, the method further includes a step of fitting the heat dissipation function, which specifically includes:

[0032] Within a specified time period, detect changes in blood flow and blood temperature;

[0033] The change in blood thermal energy is calculated based on the change in blood temperature and the blood flow rate.

[0034] A heat dissipation rate coefficient is fitted based on the change in blood thermal energy and the specified duration. The heat dissipation rate coefficient is a coefficient in the heat dissipation function to obtain the heat dissipation function.

[0035] Optionally, the number of treatment points is multiple; the method further includes:

[0036] Determine the target treatment area; wherein, multiple treatment points are located within the target treatment area, and the locations of the multiple treatment points are different;

[0037] The total volume and average tissue density of the target treatment area were detected.

[0038] Calculate the heat at each treatment point based on the output power at each treatment point, and sum the heat at all treatment points, using this sum as the total heat for treatment.

[0039] The predicted temperature rise of the target treatment area is calculated based on the total volume of the target treatment area, the average density of the tissue, and the total heat required for the treatment.

[0040] Determine whether the predicted temperature rise value exceeds the preset temperature rise threshold range; if so, adjust the output power of multiple treatment points to make the predicted temperature rise value fall within the preset temperature rise threshold range.

[0041] Optionally, the ultrasonic treatment head intermittently outputs ultrasonic signals to the treatment point; the method further includes a step of calculating the output period of the ultrasonic treatment head, specifically including:

[0042] The output cycle of the ultrasonic treatment head is divided into an interval of a first sub-cycle and multiple second sub-cycles; wherein the duration of the first sub-cycle is longer than the duration of each second sub-cycle, and the sum of the durations of the first sub-cycle and the multiple second sub-cycles is the first treatment duration.

[0043] As another technical solution, the present invention also provides an ultrasound therapy system, which includes:

[0044] An ultrasonic therapy head is used to output ultrasonic signals;

[0045] The processor is configured to execute the ultrasound dose parameter determination method as described above to control the output power of the ultrasound treatment head.

[0046] The present invention has the following beneficial effects:

[0047] The ultrasonic dose parameter determination method provided in this embodiment of the invention estimates the output power of the ultrasonic treatment head using a pre-fitted estimation function. This estimation function represents the relationship between the output power of the ultrasonic treatment head and tissue type, tissue thickness, the temperature rise required for treatment at the treatment point, and the first treatment duration. Therefore, the estimation process is based on the actual detection results of the tissue to be treated. This allows the estimation results to be adaptively adjusted according to the actual conditions of the tissue, making the estimation results more consistent with actual treatment requirements. The ultrasonic dose parameter determination method proposed in this embodiment can quickly estimate the ultrasonic dose while improving the adaptability and accuracy of the ultrasonic dose. Attached Figure Description

[0048] Figure 1 A flowchart of a method for determining ultrasonic dose parameters provided in an embodiment of the present invention;

[0049] Figure 2 This is a schematic diagram illustrating the treatment principle of the ultrasonic treatment head provided in an embodiment of the present invention;

[0050] Figure 3 Another flowchart of the method for determining ultrasonic dose parameters provided in an embodiment of the present invention. Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the invention and are not intended to limit the invention.

[0053] It is understood that, without conflict, the various embodiments of the present invention and the features thereof can be combined with each other.

[0054] It is understood that, for ease of description, the accompanying drawings of this invention only show the parts related to the embodiments of this invention, while the parts unrelated to the embodiments of this invention are not shown in the drawings.

[0055] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of the embodiments of the present invention may occur in a different order than that marked in the accompanying drawings.

[0056] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

[0057] Please refer to Figure 1 This embodiment provides a method for determining ultrasonic dose parameters, which can be used to set the parameters of an ultrasonic treatment head before the start of an ultrasonic therapy process. Specifically, the ultrasonic treatment head has at least one ultrasonic transducer for emitting ultrasonic signals. The method for determining ultrasonic dose parameters includes:

[0058] S11: Detect the tissue type and corresponding tissue thickness between the ultrasonic treatment head and the treatment point; and determine the required temperature rise for treatment based on the tissue type at the treatment point.

[0059] Specifically, such as Figure 2 As shown, during focused ultrasound therapy, the ultrasound signal emitted by the ultrasound treatment head 1 passes through the medium 2 (e.g., water or ultrasound gel) and multiple layers of different types of tissue 3a-3d in sequence, and finally reaches the treatment area 4. Moreover, the focal point of the ultrasound signal is located at the treatment point 5. Correspondingly, the detection object in step S11 is the type of tissue and the thickness of tissue that the ultrasound signal needs to pass through on the propagation path from the sound source to the focal point.

[0060] It should also be noted that the temperature rise required for treatment in step S11 is the temperature difference between the initial temperature of the tissue at the treatment point and the treatment temperature. The treatment temperature is the temperature at which the tissue at the treatment point can denature, i.e., the ablation temperature. Taking muscle tissue as an example, the treatment temperature for muscle tissue can be 60°C, while the temperature of the tissue at the treatment point can be determined by local body temperature detection, for example, 37°C. Accordingly, the required temperature rise is 23°C. Specifically, the required temperature rise can be determined by calling the pre-stored data table of tissue type and treatment temperature in the storage device; or, the operator can determine the required temperature rise based on the detected tissue type at the treatment point and their own experience.

[0061] S12: Preset first treatment duration;

[0062] S13: Calculate the output power of the ultrasonic treatment head based on tissue type, tissue thickness, first treatment duration, and pre-fitted estimation function;

[0063] The estimation function represents the relationship between the output power of the ultrasound treatment head and the tissue type, tissue thickness, and first treatment duration.

[0064] This embodiment proposes using a pre-fitted estimation function to estimate the output power of the ultrasonic treatment head. The estimation function represents the relationship between the output power of the ultrasonic treatment head and tissue type, tissue thickness, the required temperature rise for treatment, and the first treatment duration. Therefore, the estimation process is based on the actual detection results of the tissue to be treated. This allows the estimation results to be adaptively adjusted according to the actual conditions of the tissue, making the estimation results more consistent with actual treatment requirements. The ultrasonic dose parameter determination method proposed in this embodiment can quickly estimate the ultrasonic dose while improving the adaptability and accuracy of the ultrasonic dose, thereby reducing the occurrence of overtreatment or undertreatment, improving treatment efficacy, and reducing the incidence of complications.

[0065] For example, the detection method used in step S11 can be an imaging detection method. For instance, ultrasound imaging, computed tomography (CT), or magnetic resonance imaging (MR) can be used to detect tissue thickness and distinguish tissue types. Ultrasound imaging can distinguish the layers of tissue along the ultrasound signal path and acquire the thickness of each layer. It should be noted that ultrasound imaging devices have the advantages of small size and simple imaging conditions. In some treatment scenarios, the ultrasound treatment head can also function as an ultrasound imaging device, allowing detection and treatment to be completed in the same scenario. However, if the accuracy of ultrasound imaging in detecting tissue thickness is insufficient, MR or CT imaging can also be used in step S11. Both MR and CT imaging can spatially segment different tissues and perform three-dimensional reconstruction of the area to be detected, thereby separately detecting the thickness of each tissue layer and obtaining data such as skin thickness, subcutaneous fat thickness, and muscle thickness.

[0066] In some embodiments, the estimation function includes an ultrasound attenuation function, a tissue thermal conversion function, and a heat dissipation function. The ultrasound attenuation function represents the relationship between the focal power of the ultrasound signal at the focal point and the output power of the ultrasound treatment head in a specified type of tissue, indicating the attenuation effect of multiple tissue layers on the ultrasound signal along the path from the ultrasound treatment head to the treatment point. The tissue thermal conversion function represents the relationship between the focal power and the temperature rise of the tissue in a specified type of tissue, indicating the ability of that type of tissue to convert mechanical vibration into heat energy under the action of an ultrasound signal. The heat dissipation function represents the heat dissipation capacity of blood flow.

[0067] As can be seen, the estimation function proposed in this embodiment involves all aspects of the ultrasound signal that affect tissue heating during the treatment process, namely, the ultrasound signal transmission stage, the ultrasound heating stage, and the heat dissipation stage. In this way, the estimated output power can be as close as possible to the ultrasound power required for treatment, that is, the estimated output power value is neither too low nor too high, so as to effectively avoid undertreatment or overtreatment, thereby effectively improving the therapeutic effect of ultrasound therapy. Furthermore, since the multiple functions included in the estimation function in this embodiment are pre-fitted before treatment, this embodiment can improve the efficiency of determining ultrasound dosage parameters while ensuring the ultrasound therapy effect, thereby improving the overall efficiency of the treatment process and reducing the experience requirements of the operator.

[0068] As mentioned above, the output power and the first treatment duration in the estimation function are non-measured parameters, and the first treatment duration is preset. Therefore, the estimation function can be adjusted manually by adjusting the first treatment duration. Specifically, as... Figure 3 As shown, in some embodiments, after calculating the output power of the ultrasonic treatment head, the parameter determination method further includes:

[0069] S14: Determine whether the calculated output power exceeds the preset power safety threshold;

[0070] If so, adjust the first treatment duration to reduce the subsequently calculated output power to within the power safety threshold; that is, return to step S12 above to recalculate the output power.

[0071] If not, the calculated output power is sent to the ultrasound treatment head.

[0072] It should be noted that the basic principle of focused ultrasound therapy is as follows: by focusing an ultrasound signal onto a designated treatment point in the area to be treated, the tissue at the designated treatment point can be heated to the treatment temperature under the action of ultrasound and maintained at the treatment temperature for a certain period of time. In the actual process of focused ultrasound therapy, the corresponding tissue can be heated to the corresponding treatment temperature by ultrasound signal and continuously radiated for a certain period of time, thereby ablating the tissue and achieving an effective treatment effect. It can be seen that, based on the tissue type in the area to be treated and the corresponding treatment temperature, the ultrasound energy required for treatment can be determined. Then, under the condition of a preset first treatment duration, the ultrasound power at the focal point can be calculated using the relationship between energy, power and time. Specifically, according to the basic relationship between energy and power, under the condition of fixed energy, time and power are inversely proportional. Therefore, after determining in step S14 that the output power exceeds the preset safe power, the calculated output power can be reduced by extending the first treatment duration, thereby reducing the output power to within the safe power threshold.

[0073] For example, the aforementioned preset power safety threshold can be the rated power range of the ultrasonic treatment head.

[0074] In some embodiments, the parameter determination method further includes a step of pre-fitting an ultrasonic attenuation function, which specifically includes:

[0075] S21: For various types of tissues, simulate the radiation of ultrasound signals with specified output power to the tissue at multiple different focal lengths, and obtain multiple simulated focal power at multiple focal lengths and corresponding to multiple focal lengths through simulation to obtain a simulated focal power dataset.

[0076] That is, to obtain the simulated focal power of a specified tissue at different focal lengths under the same output power, so as to obtain the attenuation ability of tissues of different thicknesses to ultrasound signals; wherein the tissue is, for example, biological tissues such as skin tissue, subcutaneous adipose tissue, muscle tissue, or ultrasound medium tissues such as water or gel.

[0077] S22: Based on the specified output power, multiple focal lengths, and simulated focal power dataset, fit a single attenuation coefficient function for the tissue; whereby the single attenuation coefficient function represents the relationship between the focal length and power attenuation ratio of the ultrasound signal in the tissue.

[0078] S23: After detecting the tissue type and corresponding tissue thickness between the ultrasonic treatment head and the treatment point, i.e. after step S11, select the corresponding single attenuation coefficient function according to the tissue type detected in step S11, and calculate the corresponding single attenuation coefficient according to the corresponding single attenuation coefficient function and the detected tissue thickness.

[0079] As can be seen, the single attenuation coefficients are all calculated based on the actual measured values ​​and the pre-fitted single attenuation coefficient function. Therefore, multiple single attenuation coefficients can reflect the attenuation effect of all tissues that the ultrasound signal needs to pass through on the propagation path as accurately as possible, thus conforming to the actual treatment situation as much as possible.

[0080] S24: Calculate the attenuation coefficient based on the sum of all individual attenuation coefficients, and use the attenuation coefficient as the coefficient of the ultrasonic attenuation function to obtain the ultrasonic attenuation function.

[0081] Specifically, the attenuation coefficient calculated in step S24 above can be:

[0082]

[0083] Where Xa is the attenuation coefficient; x0 is the single attenuation coefficient of the transmission medium, such as water or ultrasonic gel. In the acoustic field, x0 is a commonly used value, usually between 0.2 and 0.05; (thi×xi)ni ×Ai is a single attenuation coefficient function for a specified tissue, where thi is the thickness of the specified tissue, which is a measured value, for example, obtained through MR or ultrasound imaging techniques; xi is the characteristic coefficient of the specified tissue, ni is the coefficient of the specified tissue, and Ai is the correction coefficient. Specifically, the parameters xi, ni, and Ai all need to be obtained through fitting. After fitting the above equation (1), the thickness thi of the specified tissue can be obtained in the detection step S11, and the thickness thi can be substituted into the above equation (1) to obtain the corresponding attenuation coefficient Xa. It can be seen that the single attenuation coefficient function pre-fitted in this embodiment has only one variable, namely the thickness of the specified tissue. Moreover, the computational workload of the single attenuation coefficient function is very small. Correspondingly, the computational workload of calculating the attenuation coefficient based on the sum of all single attenuation coefficients is also very small. In this way, the computational workload in the process of determining the ultrasound dose can be effectively reduced, the computational efficiency can be improved, and the overall efficiency of the ultrasound treatment process can be improved.

[0084] For example, if there are multiple different types of tissue between the ultrasonic treatment head and the treatment point, and the corresponding tissue thickness is detected, then the multiple tissue thicknesses can be substituted into the above equation (1) to calculate the corresponding attenuation coefficient Xa:

[0085] Xa = 1 - x0 - {(th1 × x1)} n1 A1+(th2×x2) n2 A2 +…} (2)

[0086] Where th1 is, for example, the thickness detection value of skin tissue, and correspondingly, x1, n1 and A1 are all coefficients in the single attenuation coefficient function corresponding to skin tissue; th2 is, for example, the thickness detection value of subcutaneous adipose tissue, and correspondingly, x2, n2 and A2 are all coefficients in the single attenuation coefficient function corresponding to subcutaneous adipose tissue; and so on, the above formula (2) may also include single attenuation coefficients of muscle tissue, single attenuation coefficients of tumor tissue or single attenuation coefficients of fibroid tissue, etc., and other calculation terms corresponding to different types of tissues.

[0087] Furthermore, after calculating the attenuation coefficient Xa, it can be substituted into the ultrasonic attenuation function to obtain the following formula:

[0088] Pf=Xa×Pa (3)

[0089] Where Pf is the focal ultrasound power, i.e., the ultrasound power at the treatment point; Pa is the output power of the ultrasound treatment head. Specifically, after obtaining the focal ultrasound power Pf, the output power Pa of the ultrasound treatment head can be calculated, thereby determining the key parameter in the ultrasound dosage parameters: output power Pa.

[0090] Specifically, the output power Pa can be calculated using the modified formula of the above equation (3): Pa = Pf / Xa.

[0091] It is easy to understand that the larger the amount of data, the higher the accuracy of the obtained ultrasound attenuation function, and the more accurately the tissue's ability to attenuate ultrasound is reflected by the function. However, if data is collected through actual measurements, the larger the amount of data, the higher the cost of the actual measurements. This embodiment, by using simulation, can obtain a large amount of data while reducing the cost of data acquisition.

[0092] For example, the fitting method used in steps S21-S22 above can be linear regression fitting, or it can be second-order or higher-order fitting. Among them, linear regression fitting has a small amount of computation but limited accuracy; higher-order fitting requires more data and has a larger amount of computation, but it can improve the accuracy of the fitted function.

[0093] It should be noted that since different types of tissues have different attenuation effects on ultrasound signals, the above data simulation step S21 and fitting step S22 need to be performed once for each type of tissue. In this way, each type of tissue has a corresponding single attenuation coefficient function.

[0094] Furthermore, since different models of ultrasonic treatment heads may produce different sound field morphologies, focal point shapes, and focal point positions, the corresponding single attenuation coefficient functions may differ when treating the same type of tissue. Therefore, for each model of ultrasonic treatment head, the aforementioned data simulation step S21 and fitting step S22 need to be performed once. In this way, each model of ultrasonic treatment head has a set of single attenuation coefficient functions corresponding to different types of tissue. For example, the corresponding single attenuation coefficient function sets can be stored in the controller connected to the ultrasonic treatment head in the form of a data table.

[0095] Furthermore, in some specific embodiments, the step of calculating the ultrasonic attenuation function further includes:

[0096] S211: Acquire a specified type of tissue and control the ultrasound treatment head to output a verification ultrasound signal;

[0097] It should be noted that "specified tissue type" means that the tissue type is fixed in a single experiment; for example, a piece of muscle tissue is obtained and the ultrasound treatment head under test is controlled to output a verification ultrasound signal to it; while the tissue type used in different experiments should be different.

[0098] S212: Detect the temperature rise of the tissue located at the focal point and calculate the corresponding calibration focal power based on the temperature rise;

[0099] S213: Locate the corresponding simulated focus power value in the simulated focus power dataset corresponding to the organization, and calculate the difference between the verification focus power and the corresponding simulated focus power;

[0100] S214: Determine whether the difference exceeds the preset calibration range; if not, continue with step S22, which involves fitting a single attenuation coefficient function of the tissue; if so, reacquire the simulation focal power dataset. Specifically, the preset calibration range can be set manually, for example, from 0W to 0.5W.

[0101] In this way, by selecting the same type of tissue and the same model of ultrasound treatment head, and comparing the measured calibration focal power with the simulated focal power, the accuracy of the data obtained from the simulation can be effectively verified. Moreover, the data verification steps S211-S214 above can use sampling verification, so that the accuracy of the entire simulated focal power dataset can be verified with fewer experiments, thereby improving the accuracy of the subsequently fitted function while reducing experimental costs.

[0102] It should be noted that steps S211-S214 above are verification steps, and this application does not limit their order in the entire method. Preferably, the above verification steps can be performed before fitting a single attenuation coefficient function, so as to ensure the accuracy of the data involved in the fitting before fitting, thereby avoiding repeated fitting steps and improving the efficiency of the entire process of fitting the ultrasonic attenuation function.

[0103] In some embodiments, the parameter determination method further includes a step of fitting a tissue thermal conversion function, specifically, the tissue thermal conversion function representing the ability of this type of tissue to convert the mechanical energy of an ultrasound signal into thermal energy; this step specifically includes:

[0104] S31: Control the ultrasonic treatment head to emit ultrasonic signals to various types of tissues with a specified focal power and duration; obtain the corresponding tissue density and the focal volume of the ultrasonic treatment head;

[0105] Specifically, the actual output power corresponding to the specified focal power can be calculated based on the ultrasonic attenuation function mentioned above; or, it can be obtained from the simulated focal power dataset mentioned above.

[0106] S32: Detect the temperature rise of the corresponding tissue;

[0107] S33: Calculate the accumulated ultrasonic energy at the focal point based on the specified focal power and specified duration;

[0108] S34: Fit the thermal conversion coefficient based on the ultrasound energy, focal volume, tissue density, and temperature rise. The thermal conversion coefficient is the coefficient in the tissue thermal conversion function to obtain the tissue thermal conversion function.

[0109] Specifically, the heat conversion coefficient fitted in step S34 above can be:

[0110] Ch=E / (Vol×ρ×Δt×j)(4)

[0111] E=Pf×tm(5)

[0112] Wherein, Ch is the thermal conversion coefficient, which is the parameter to be fitted; E is the ultrasonic energy at the focal point; Pf is the focal power, which is a known parameter; tm is the duration of ultrasonic signal radiation, i.e., the treatment duration, and correspondingly, the thermal energy E at the focal point can be calculated by the above formula (5); Vol is the focal volume, which is a fixed parameter of the ultrasonic treatment head; Δt is the temperature rise, i.e., the difference between the temperature detection values ​​of the corresponding tissue before and after ultrasonic radiation; ρ is the tissue density, which is a known parameter corresponding to the tissue type; j is the thermal-mechanical equivalent coefficient, specifically approximately 4.184 joules / calorie. Specifically, various types of tissues and their corresponding multiple thermal conversion coefficients Ch can be stored in the form of a data table.

[0113] Furthermore, after fitting the heat transfer coefficient Ch, the tissue heat transfer function can be obtained as follows:

[0114] E=Δt×Ch×Vol×ρ×j(6)

[0115] In this way, during the process of determining the ultrasonic dose, the detected tissue type and corresponding tissue density ρ, along with the known focal volume Vol, thermal conversion coefficient Ch, and the required temperature rise of the ultrasonic treatment head, can be used to calculate the ultrasonic energy E required at the focal point for treatment. This allows us to know how much ultrasonic energy needs to be applied at the focal point to raise the tissue temperature to the preset treatment temperature.

[0116] Furthermore, in some specific embodiments, the step of fitting the tissue heat transfer function further includes:

[0117] S35: Perform magnetic resonance imaging (MR) on various types of tissues and obtain the corresponding T2 signals from the MR images;

[0118] Specifically, the T2 signal represents the decay and disappearance time of the transverse magnetic vector in the MR detection results;

[0119] S36: Based on the tissue thermal conversion function and T2 signal corresponding to various different types of tissues, fit the functional relationship between the T2 signal and the tissue thermal conversion function.

[0120] Specifically, regarding thermal conversion capacity, the inventors discovered through experiments that it is related not only to tissue density but also to tissue water content. Tissue water content has a significant impact on its thermal conversion capacity; for example, the thermal conversion capacity of liver tissue differs greatly from that of uterine fibroid tissue. Furthermore, the T2 signal detected during MR imaging can accurately characterize the water-expressing signal in the detected region; that is, the T2 signal can accurately represent the tissue water content. Therefore, this embodiment establishes a relationship between the T2 signal and the tissue thermal conversion function, thus correlating the thermal conversion coefficient Ch with the tissue water content, thereby obtaining a thermal conversion coefficient Ch that approximates the tissue's true thermal conversion capacity as closely as possible.

[0121] Specifically, the functional relationship fitted in step S36 above is as follows:

[0122] Ch = a(T2) 2 + b (7)

[0123] Where a and b are coefficients of the equation, both of which are parameters to be fitted. The coefficients a and b can be fitted by multiple thermal conversion coefficients Ch and multiple corresponding T2 signals. Thus, in the process of determining the ultrasound dose, in step S11, the treatment point can be detected by MR technology to obtain the measured T2 signal value. Then, the T2 signal value can be substituted into the above equation (7) to calculate the corresponding thermal conversion coefficient Ch of the tissue. Then, the thermal conversion coefficient Ch can be substituted into the tissue thermal conversion function to prepare for the subsequent estimation of the actual energy E required by the tissue to be treated.

[0124] In some embodiments, the parameter determination method further includes a step of fitting a heat dissipation function. Specifically, the heat dissipation of the tissue to be treated is mainly carried away by the continuous flow of blood. Therefore, the heat dissipation rate of the tissue is related to the blood flow velocity and volume in its vicinity and / or within it, and not to the tissue's own parameters such as tissue type or volume. Specifically, blood flow velocity is generally positively correlated with the heat dissipation rate, that is, the faster the blood flow velocity, the faster the heat dissipation rate. The step of fitting the heat dissipation function specifically includes:

[0125] S41: Detect changes in blood flow and blood temperature within a specified time period;

[0126] S42: Calculate the change in blood heat energy based on the change in blood temperature and blood flow rate;

[0127] S43: Fit the heat dissipation rate coefficient based on the change in blood heat energy and the specified duration. The heat dissipation rate coefficient is a coefficient in the heat dissipation function to obtain the heat dissipation function.

[0128] Specifically, the heat dissipation rate coefficient can represent the rate at which blood flow carries away heat. It should be noted that since blood flow velocity is affected by various factors, such as heart rate, the above steps of detecting changes in blood flow and blood temperature can be performed just before the start of ultrasound treatment. In this way, the heat dissipation function fitted subsequently can be as close as possible to the actual heat dissipation rate of blood flow during ultrasound treatment, thereby making the final calculation of ultrasound dose more accurate.

[0129] Specifically, the heat dissipation function fitted in step S43 above is:

[0130] EL=S×tm (8)

[0131] Wherein, EL is the change in blood thermal energy, that is, the total heat dissipation through blood flow; S is the heat dissipation rate coefficient; and tm is the treatment duration.

[0132] It should be noted that blood flow velocity detection is a relatively mature technology. Therefore, MR technology or color Doppler ultrasound technology can be used to measure blood flow velocity in the above steps.

[0133] For example, steps S41-S43 of fitting the heat dissipation function can be performed after step S11.

[0134] In summary, by combining the pre-fitted ultrasound attenuation function, tissue heat conversion function, and heat dissipation function, the output power of the ultrasound treatment head can be deduced. Specifically, by combining equations (3), (6), and (8) above, the relationship between the output power of ultrasound treatment and the target temperature rise of the treated tissue can be derived as follows:

[0135] E=Xa×Pa×tm-S×tm=Δt×Ch×Vol×ρ×j(9)

[0136] Where tm is the treatment duration, which can be the preset first treatment duration; Δt is the required temperature increase for treatment, which is the temperature difference between the initial temperature at the treatment point and the target temperature required for treatment. It can be a preset value. For example, if the initial temperature is 37℃ and the target temperature is 60℃, then the required temperature increase Δt is 23℃. As mentioned above, the other parameters Xa, Ch, Vol, ρ, and j in the above formula (9) are all pre-fitted values; Pa is the output power of the ultrasonic treatment head, which is the value to be calculated, that is, the only unknown in the above formula (9). Therefore, the output power Pa of the ultrasonic treatment head can be calculated, and in the subsequent treatment process, the output power of the ultrasonic treatment head can be set to the output power Pa.

[0137] Since ultrasonic therapy heads typically output ultrasonic signals to the treatment site at intervals, in some embodiments, the parameter determination method further includes the step of calculating the output period of the ultrasonic therapy head, specifically including:

[0138] S51: The output cycle of the ultrasound treatment head is divided into an interval of first sub-cycle and multiple second sub-cycles; wherein the duration of the first sub-cycle is longer than the duration of each second sub-cycle, and the sum of the durations of the first sub-cycle and multiple second sub-cycles is the first treatment duration.

[0139] Specifically, the first sub-cycle in the output cycle of ultrasound therapy is the longest, allowing the target tissue to be heated from the initial temperature to the target temperature in the first sub-cycle, thus achieving initial heating; while the subsequent second sub-cycles can be shorter, so as to keep the target tissue at the target temperature without further heating, thereby avoiding unnecessary damage.

[0140] For example, the duration of the first sub-cycle can be 40% of the duration of the first treatment. Correspondingly, the duration of the second sub-cycle can be adjusted by adjusting the number of second sub-cycles, thereby avoiding the duration of the second sub-cycle from exceeding the preset duration range. For example, the number of second sub-cycles can be 4, and each second sub-cycle can be 15% of the duration of the first treatment.

[0141] For example, the preset duration range of the second sub-cycle duration can be 0.5s to 5s.

[0142] For example, the interval between two sub-cycles of the ultrasonic treatment head can be in the range of 1s to 5s. Within this range, the interval between sub-cycles will not be too short, which would lead to excessive heat accumulation and damage to the ultrasonic treatment head. Nor will the interval between sub-cycles be too long, which would lead to excessive heat loss and inaccurate estimated dose parameters.

[0143] As described above, the parameter determination method can calculate the dose parameters for a single treatment point. However, in actual ultrasound treatment, there are usually more than one treatment point in the treatment area, and these treatment points are distributed in different locations in space. Therefore, in some embodiments, the parameter determination method further includes:

[0144] S61: Identify the target treatment area;

[0145] Among them, multiple treatment points are located within the target treatment area, and the locations of the multiple treatment points are different;

[0146] S62: Detect the total volume and average tissue density of the target treatment area;

[0147] S63: Calculate the heat at each treatment point based on the output power of each treatment point, and sum the heat at all treatment points, and use this sum as the total heat for treatment.

[0148] S64: Calculate the predicted temperature rise of the target treatment area based on the total volume of the target treatment area, the average tissue density, and the total heat of treatment.

[0149] S65: Determine whether the predicted temperature rise value exceeds the preset temperature rise threshold range;

[0150] If yes, then the output power of multiple treatment points is adjusted to ensure that the predicted temperature rise value is within the preset temperature rise threshold range; if no, it indicates that the output power of multiple treatment points meets the requirements.

[0151] Specifically, if the calculated total temperature rise prediction value is less than the minimum value of the temperature rise threshold range, it indicates that the ultrasound dose is insufficient. In this case, the output power corresponding to at least one of the multiple treatment points can be appropriately increased to avoid the total temperature rise of multiple treatment points being too low, resulting in incomplete ablation of the tissue in the target treatment area and thus treatment failure. If the calculated total temperature rise prediction value is greater than the maximum value of the temperature rise threshold range, it indicates that the ultrasound dose is too high. In this case, the output power corresponding to at least one of the multiple treatment points can be appropriately reduced to avoid the total temperature rise of multiple treatment points being too high, resulting in damage to tissues that do not need to be treated.

[0152] For example, the preset temperature rise threshold range can be 15℃ to 40℃.

[0153] Specifically, the predicted temperature rise value in step S64 above can be:

[0154] tall=(Eall-EL) / (V×ρ×j)(10)

[0155] Where tall is the total predicted temperature rise; Eall is the total energy at the focal point; EL is the total energy dissipated by blood flow; V is the total volume of the target treatment area; and ρ is the average density of the tissue in the target treatment area.

[0156] In the above formula (10), the total focal energy Eall is the focal heat of all treatment points in the target treatment area. Specifically, the total focal energy Eall can be expressed by the following formula:

[0157]

[0158] Where n is the number of treatment points; Ei is the output energy corresponding to a single treatment point, which can be calculated according to the above formula (9).

[0159] It should be noted that the treatment doses at multiple treatment points within the entire target treatment area are not necessarily the same. This is because ultrasound treatment of the first treatment point in the treatment sequence may cause some damage to the boundary of the target treatment area. Taking a uterine fibroid as an example, ultrasound treatment of the first treatment point may damage the capsule of the uterine fibroid. Therefore, in some implementations, the output power corresponding to the first treatment point needs to be higher than the output power corresponding to other treatment points that are treated subsequently.

[0160] As another technical solution, this embodiment also provides an ultrasound therapy system, which includes an ultrasound therapy head and a controller. The ultrasound therapy head is used to output ultrasound signals; the processor is used to execute the ultrasound dose parameter determination method described above to determine the output power corresponding to the actual treatment situation, so as to control the output power of the ultrasound therapy head.

[0161] Moreover, as mentioned above, the processor can also determine dose parameters such as treatment duration, output cycle duration, and output cycle interval duration by executing the ultrasound dose parameter determination method described above.

[0162] For example, the processor can communicate with external detection devices to acquire the required detection data, such as MR devices, CT devices, or ultrasound imaging devices. Alternatively, the processor can communicate with external human-machine interface devices to allow operators to manually input detection data and preset data.

[0163] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for determining ultrasonic dosage parameters, characterized in that, include: Detect the tissue type and corresponding tissue thickness between the ultrasound treatment head and the treatment point; The required temperature rise for treatment is determined based on the tissue type at the treatment site. Preset the first treatment duration; The output power of the ultrasonic treatment head is calculated based on the tissue type, the tissue thickness, the temperature rise, the first treatment duration, and a pre-fitted estimation function; the estimation function represents the relationship between the output power of the ultrasonic treatment head and the tissue type, the tissue thickness, the temperature rise, and the first treatment duration.

2. The method for determining ultrasonic dose parameters according to claim 1, characterized in that, The estimation function includes the ultrasound attenuation function, the tissue heat conversion function, and the heat dissipation function; Wherein, the ultrasound attenuation function represents the relationship between the focal power of the ultrasound signal at the focal point and the output power of the ultrasound treatment head in a specified type of tissue; the tissue heat transfer function represents the relationship between the focal power and the temperature rise of the tissue in a specified type of tissue; and the heat dissipation function represents the heat dissipation capacity of blood flow.

3. The method for determining ultrasonic dose parameters according to claim 1, characterized in that, After calculating the output power of the ultrasonic treatment head, the method further includes: Determine whether the calculated output power exceeds a preset power safety threshold; if so, adjust the first treatment duration to reduce the subsequently calculated output power to within the power safety threshold; if not, send the calculated output power to the ultrasound treatment head.

4. The method for determining ultrasonic dose parameters according to claim 2, characterized in that, The method further includes a step of pre-fitting the ultrasonic attenuation function, which specifically includes: For various types of tissues, ultrasound signals with specified output power are radiated onto the tissues at multiple different focal lengths through simulation. The simulated focal power data set is obtained by acquiring multiple simulated focal lengths and multiple simulated focal power data corresponding to the multiple focal lengths. Based on the specified output power, multiple focal lengths, and the simulated focal power dataset, a single attenuation coefficient function of the tissue is fitted; wherein, the single attenuation coefficient function represents the relationship between the focal length and the power attenuation ratio of the ultrasound signal in the tissue; After the step of detecting the tissue type and corresponding tissue thickness between the ultrasonic treatment head and the treatment point, the corresponding single attenuation coefficient function is selected according to the detected tissue type, and the corresponding single attenuation coefficient is calculated according to the corresponding single attenuation coefficient function and the detected tissue thickness. The attenuation coefficient is calculated based on the sum of all the individual attenuation coefficients, and the attenuation coefficient is used as the coefficient of the ultrasonic attenuation function to obtain the ultrasonic attenuation function.

5. The method for determining ultrasonic dose parameters according to claim 4, characterized in that, The step of calculating the ultrasonic attenuation function further includes: Acquire a specified type of tissue and control the ultrasound treatment head to output a verification ultrasound signal; The temperature rise of the tissue located at the focal point is detected, and the corresponding verification focal power is calculated based on the temperature rise. Find the corresponding simulated focus power value in the simulated focus power dataset corresponding to the organization, and calculate the difference between the verification focus power and the corresponding simulated focus power; Determine whether the difference exceeds the preset calibration range; if not, continue with the step of fitting the single attenuation coefficient function of the tissue; if so, reacquire the simulation focal power dataset.

6. The method for determining ultrasonic dose parameters according to claim 2, characterized in that, The method further includes a step of fitting the tissue heat transfer function, which specifically includes: The ultrasonic treatment head is controlled to emit ultrasonic signals to various types of tissues with a specified focal power and duration; the corresponding tissue density is obtained, and the focal volume of the ultrasonic treatment head is obtained. Detect the temperature rise of the corresponding tissue; The accumulated ultrasonic energy at the focal point is calculated based on the specified focal power and the specified duration. A heat conversion coefficient is fitted based on the ultrasound energy, the focal volume, the tissue density, and the temperature rise, and the heat conversion coefficient is used as a coefficient in the tissue heat conversion function to obtain the tissue heat conversion function.

7. The method for determining ultrasonic dose parameters according to claim 6, characterized in that, The step of fitting the tissue heat conversion function further includes: Magnetic resonance imaging was performed on various types of tissues, and the corresponding T2 signals in the magnetic resonance images were acquired respectively. Based on the thermal conversion coefficients and T2 signals corresponding to various different types of the tissues, a functional relationship between the T2 signal and the thermal conversion coefficients is fitted.

8. The method for determining ultrasonic dose parameters according to claim 2, characterized in that, The method further includes a step of fitting the heat dissipation function, which specifically includes: Within a specified time period, detect changes in blood flow and blood temperature; The change in blood thermal energy is calculated based on the change in blood temperature and the blood flow rate. A heat dissipation rate coefficient is fitted based on the change in blood thermal energy and the specified duration. The heat dissipation rate coefficient is a coefficient in the heat dissipation function to obtain the heat dissipation function.

9. The method for determining ultrasonic dose parameters according to claim 1, characterized in that, The number of treatment points is multiple; the method further includes: Determine the target treatment area; wherein, multiple treatment points are located within the target treatment area, and the locations of the multiple treatment points are different; The total volume and average tissue density of the target treatment area were detected. Calculate the heat at each treatment point based on the output power at each treatment point, and sum the heat at all treatment points, using this sum as the total heat for treatment. The predicted temperature rise of the target treatment area is calculated based on the total volume of the target treatment area, the average density of the tissue, and the total heat required for the treatment. Determine whether the predicted temperature rise value exceeds the preset temperature rise threshold range; if so, adjust the output power of multiple treatment points to make the predicted temperature rise value fall within the preset temperature rise threshold range.

10. The method for determining ultrasonic dose parameters according to claim 3, characterized in that, The ultrasonic treatment head intermittently outputs ultrasonic signals to the treatment point; The method further includes a step of calculating the output cycle of the ultrasonic treatment head, specifically including: The output cycle of the ultrasonic treatment head is divided into an interval of a first sub-cycle and multiple second sub-cycles; wherein the duration of the first sub-cycle is longer than the duration of each second sub-cycle, and the sum of the durations of the first sub-cycle and the multiple second sub-cycles is the first treatment duration.

11. An ultrasound therapy system, characterized in that, include: An ultrasonic therapy head is used to output ultrasonic signals; A processor is configured to execute the ultrasonic dose parameter determination method as described in any one of claims 1-10 to control the output power of the ultrasonic treatment head.

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