Method and device for acquiring steady-state temperature of target tissue with physiological temperature affected by medium

Abstract

The invention relates to a method and a device for acquiring a steady-state temperature of a target tissue with a medium influencing a physiological temperature, the method is applied to a computer, and the method comprises the following steps: acquiring a three-dimensional model of a magnetic resonance image of a region of interest; and after the physiological temperature is influenced by the medium, obtaining the steady-state temperature of the target tissue based on the three-dimensional model and the biological heat transfer model. Before formal temperature measurement, the influence mechanism influences the physiological body temperature of the target tissue, and magnetic resonance cannot directly measure the winner body temperature, so that the steady-state temperature of the target tissue after heat transfer and stabilization is calculated by constructing the spatial model and the biological heat transfer model of the local area. Therefore, the steady-state temperature of the target tissue can be obtained when the physiological temperature is influenced by the external medium in the magnetic resonance environment.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement, and in particular to a method and device for acquiring the steady-state temperature of a target tissue whose physiological temperature is affected by a medium. Background Art

[0002] Magnetic resonance-guided high-intensity focused ultrasound ablation has been used in the treatment of many diseases. Combined with magnetic resonance temperature measurement, the temperature changes during the ablation process can be visualized in imaging, which enables closed-loop monitoring of the entire treatment process to ensure safety and effectiveness.

[0003] At present, the most widely accepted magnetic resonance temperature measurement method in clinical practice is the proton resonance frequency (PRF) offset method of water protons. The magnetic resonance temperature measurement method can only measure the relative change of temperature. The baseline temperature of the target tissue and the heating temperature of the resonance measurement cannot be directly obtained in the magnetic resonance environment. Therefore, it is necessary to determine the reference temperature of the baseline phase and the temperature change measured by the PRF to obtain the magnetic resonance heating temperature, which more accurately reflects the degree of treatment. In general, the normal range of human body temperature is between 36.1°C and 37.1°C (i.e. physiological body temperature). In practical applications, 37°C is usually taken as the baseline temperature, and PRF temperature measurement is performed on this basis to monitor the treatment.

[0004] However, the aforementioned scheme for determining physiological body temperature lacks consideration of the influence of external media on physiological body temperature conditions. For example, when the target tissue is wrapped in the middle of the medium material, the physiological temperature of the target tissue will rise or fall sharply. The temperature equilibrium requires a certain amount of time, and it is no longer the normal physiological temperature of 37°C. If the conventional temperature is used for calculation, the reference temperature during magnetic resonance temperature measurement will be inaccurate, affecting the accuracy of magnetic resonance research and scheme settings. In summary, there is currently a lack of a method and device for directly obtaining the reference temperature of the target tissue and the heating temperature for measuring resonance in a magnetic resonance environment, and further, when the medium affects the physiological temperature of the target tissue, the steady-state temperature of the target tissue after being affected by the medium is obtained. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a method and device for obtaining the steady-state temperature of the target tissue whose physiological temperature is affected by the medium, so as to realize the steady-state temperature measurement of the target tissue whose physiological temperature is affected by the medium under the magnetic resonance environment.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In one aspect of the present invention, a method for obtaining the steady-state temperature of a target tissue in which a medium affects the physiological temperature is provided, which is applied to a computer and comprises the following steps:

[0008] obtaining a three-dimensional model of the magnetic resonance image of the region of interest;

[0009] After the physiological temperature is affected by the medium, the steady-state temperature of the target tissue is obtained based on the three-dimensional model and the bioheat transfer model.

[0010] As a preferred technical solution, a method for obtaining a three-dimensional model of a magnetic resonance image of a region of interest includes:

[0011] acquiring magnetic resonance images of one, two or more time frames;

[0012] Acquire a magnetic resonance image of the region of interest from the magnetic resonance image, wherein the magnetic resonance temperature measurement image of the region of interest includes a regional image of a target tissue and an influencing structure, wherein the influencing structure is a structure that affects the physiological temperature of the target tissue;

[0013] A spatial model is constructed based on the magnetic resonance image.

[0014] As a preferred technical solution, the method for constructing a spatial model includes:

[0015] On the magnetic resonance image, the target tissue and the affected structure are identified and marked, and a spatial model is constructed.

[0016] As a preferred technical solution, a method for obtaining the steady-state temperature of a target tissue based on the bioheat transfer model includes:

[0017] Acquire several instantaneous temperatures of target tissues in continuous time;

[0018] A steady-state time and a steady-state temperature of the target tissue are obtained from the instantaneous temperature.

[0019] As a preferred technical solution, a method for obtaining several instantaneous temperatures of a target tissue in a continuous time includes:

[0020]

[0021] Among them, ρ t represents the density of the target tissue, c t represents the specific heat capacity of the target tissue, k represents the thermal conductivity of the target tissue, and ρ b represents the density of blood, c b represents the specific heat capacity of blood, ω b represents the blood perfusion rate, represents the change of instantaneous temperature in space with time, represents the blood temperature, Q meta , Q ext They represent the heat deposited at the focus by metabolic heat source and external heat source respectively.

[0022] As a preferred technical solution, the structure that affects physiological body temperature includes a water bag, a focused ultrasound transducer and a medium, the medium includes liquid and crystal, and the target tissue includes prostate and breast.

[0023] Another aspect of the present invention provides a method for obtaining the magnetic resonance heating temperature of a target tissue, comprising:

[0024] obtaining a three-dimensional model of the magnetic resonance image of the region of interest;

[0025] After the physiological temperature is affected by the medium, the steady-state temperature of the target tissue is obtained based on the three-dimensional model and the bioheat transfer model;

[0026] Acquiring a magnetic resonance temperature measurement image of the region of interest;

[0027] According to the magnetic resonance temperature measurement image, obtaining a temperature change value of the magnetic resonance image;

[0028] The magnetic resonance heating temperature of the target tissue is obtained according to the temperature change value and the steady-state temperature.

[0029] As a preferred technical solution, the external heat source of the magnetic resonance temperature measurement image includes one, two or more of radio frequency, focused ultrasound and microwave.

[0030] As a preferred technical solution, a method for obtaining a temperature change value of a magnetic resonance image according to the magnetic resonance temperature measurement image includes:

[0031] acquiring a phase map of a magnetic resonance temperature image;

[0032] Acquire the phase change value of the region of interest through the phase map;

[0033] A temperature change value of the region of interest is obtained according to the phase change value.

[0034] As a preferred technical solution, a method for obtaining a temperature change value of an area of ​​interest according to the phase change value includes:

[0035]

[0036] Where ΔT represents the temperature change, φ T represents the phase after temperature change, φ0 represents the phase corresponding to steady-state temperature, γ represents the gyromagnetic ratio, α represents the temperature sensitivity coefficient, B0 represents the magnetic field intensity, and TE represents the echo time of the gradient echo sequence.

[0037] Another aspect of the present invention provides a method for obtaining a magnetic resonance temperature time domain curve, comprising:

[0038] The aforementioned method for obtaining the magnetic resonance heating temperature of the target tissue;

[0039] A time domain magnetic resonance heating temperature curve is obtained according to the time domain model and the instantaneous magnetic resonance heating temperature of the target tissue.

[0040] Another aspect of the present invention provides a device for implementing the aforementioned method for obtaining the steady-state temperature of a target tissue in which the medium affects the physiological temperature, comprising:

[0041] An influencing mechanism, connected to the target tissue, and used to influence the physiological temperature of the target tissue;

[0042] A three-dimensional modeling mechanism, used to obtain magnetic resonance images of the influencing mechanism and the region of interest of the target tissue, and construct a three-dimensional model;

[0043] The steady-state temperature acquisition mechanism is connected to the three-dimensional modeling mechanism and is used to obtain the steady-state temperature of the target tissue based on the three-dimensional model and the biological heat transfer model.

[0044] Another aspect of the present invention provides a system for obtaining a magnetic resonance heating temperature of a target tissue, comprising:

[0045] A device for acquiring the steady-state temperature of the target tissue in which the aforementioned medium affects the physiological temperature;

[0046] a temperature change acquisition device, connected to the steady-state temperature measurement device, for acquiring a temperature change value of the magnetic resonance image based on the magnetic resonance temperature measurement image;

[0047] The magnetic resonance temperature acquisition device is connected to the steady-state temperature measurement device and the temperature change acquisition device, and is used to obtain the magnetic resonance heating temperature of the target tissue according to the temperature change value and the steady-state temperature.

[0048] Another aspect of the present invention provides a computer-readable storage medium comprising one or more programs for execution by one or more processors of an electronic device, wherein the one or more programs include instructions for executing the aforementioned method for obtaining the steady-state temperature of a target tissue affected by the physiological temperature of the medium.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] In a magnetic resonance environment, the steady-state temperature of the target tissue is acquired when the physiological temperature is affected by external media: Before the formal temperature measurement is performed, since the influencing mechanism affects the physiological temperature of the target tissue and magnetic resonance cannot directly measure the body temperature, a spatial model and a biological heat transfer model of the local area are constructed to calculate the steady-state temperature of the target tissue after the heat is transferred and stabilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of a process for obtaining the magnetic resonance heating temperature of a target tissue in an embodiment;

[0052] Figure 2 A schematic diagram of a model of a prostate and a cooling water bag in an embodiment;

[0053] Figure 3 Schematic diagram of temperature distribution in biological heat transfer simulation in the embodiment;

[0054] Figure 4 It is a schematic diagram of a device for realizing a method for obtaining a steady-state temperature of a target tissue in which a medium affects a physiological temperature in an embodiment;

[0055] Figure 5 is a schematic diagram of a system for obtaining the magnetic resonance heating temperature of a target tissue in an embodiment,

[0056] Among them, 100, a device for acquiring the steady-state temperature of a target tissue whose physiological temperature is affected by a medium, 110, an influencing mechanism, 120, a three-dimensional modeling mechanism, 130, a steady-state temperature acquisition mechanism, 200, a temperature change acquisition device, and 300, a magnetic resonance temperature acquisition device. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0058] Example 1

[0059] This embodiment takes the transrectal focused ultrasound prostate ablation treatment scenario as an example, which usually uses 37°C directly as the reference temperature, which is inappropriate. In order for ultrasound to pass smoothly through tissues such as the rectal wall and prostate capsule, the ultrasound transducer will be wrapped in a layer of sound-transmitting membrane, and the membrane will be filled with 14°C constant temperature cooling water for heat dissipation of the ultrasound transducer during heating and coupling of the sound path during ultrasound propagation. Obviously, structurally, the prostate is very close to the outer wall of the membrane containing cooling water. Due to biological heat transfer, the 14°C cooling water in the membrane will cool the prostate tissue, causing its reference temperature to be lower than 37°C, resulting in inaccurate magnetic resonance temperature measurement.

[0060] In view of the above problems, this embodiment provides a method for obtaining the steady-state temperature of a target tissue whose physiological temperature is affected by a medium, which is applied to a computer. Hereinafter, the method will be described by taking the gland as the target tissue, the water bag, the focused ultrasound transducer and the medium as the external influences. The method includes the following steps:

[0061] Step S1, obtaining a three-dimensional model of the magnetic resonance image of the region of interest. The spatial model is constructed by identifying and marking the target tissue and the affected structure on the magnetic resonance image. This step includes the following sub-steps:

[0062] Step S101, acquiring magnetic resonance images of one, two or more time frames.

[0063] The size of the prostate and the spatial relationship between the prostate and the cooling water bag vary from person to person. In order to simulate bioheat transfer more accurately, the prostate (i.e., the target tissue) and the cooling water bag (i.e., the structure that affects the physiological body temperature) are scanned based on the T2-weighted sequence of magnetic resonance, and magnetic resonance imaging images of one or more time frames are obtained to perform bioheat transfer simulation of prostate cooling.

[0064] Preferably, after obtaining the magnetic resonance imaging images of one or more time frames, filtering and averaging processing is further performed to optimize the imaging quality.

[0065] Step S102, obtaining a magnetic resonance image of a region of interest from the magnetic resonance image, wherein the magnetic resonance temperature measurement image of the region of interest includes regional images of the target tissue and the influencing structure, wherein the influencing structure is a structure that affects the physiological temperature of the target tissue.

[0066] Exemplarily, the structure affecting physiological body temperature may include a water bag, a focused ultrasound transducer and a medium, the medium includes liquid, crystal, and the target tissue includes prostate and breast.

[0067] Step S103: constructing a spatial model according to the magnetic resonance image.

[0068] like Figure 2 The figure shows a schematic diagram of the prostate space model. The cooling water bag is simplified into a sphere and the initial temperature is set to 37°C. The cooling water bag is simplified into a cone, which contains a focused ultrasound transducer and circulates 14°C constant temperature cooling water in the membrane. The prostate and the water bag are surrounded by other tissues, and the initial temperature is also 37°C. Using this three-dimensional model and these initial temperatures as the starting conditions, the solution of the biological heat transfer equation is solved.

[0069] Preferably, this step realizes the marking of the target tissue and the structure affecting the physiological body temperature by interacting with the user, thereby completing the construction of the spatial model.

[0070] Step S2, after the physiological temperature is affected by the medium, the steady-state temperature of the target tissue is obtained based on the three-dimensional model and the biological heat transfer model. Specifically, this step includes the following sub-steps:

[0071] Step S201, obtaining several instantaneous temperatures of the target tissue within a continuous time. Specifically, the temperature is calculated by the following formula:

[0072]

[0073] Among them, ρ t Indicates the density of the target tissue. In this case, it can be 1060kg / m 3 , c t represents the specific heat capacity of the target tissue, which can be taken as 3639 J / kg / ℃ in this example, k represents the thermal conductivity of the target tissue, which can be taken as 3825 J / kg / ℃ in this example, and ρ b Indicates the density of blood, which can be 1000kg / m 3 , c b represents the specific heat capacity of blood, which can be taken as 3825 J / kg / ℃ in this example, ω b Indicates blood perfusion rate, unit: ml / min / 100g or ml / min / m 3 , that is, the blood flow per unit mass or volume flowing into an organ per unit time, represents the change of instantaneous temperature in space with time, that is, Indicates blood temperature, usually 37°C, Q meta , Q ext They represent the heat deposited at the focus by metabolic heat source and external heat source respectively. In the focused ultrasound ablation treatment scenario of the prostate, the heating time is short and Q meta The effect of Q can be ignored. ext That is, the heat deposition on the focus. Preferably, the external heat source of the magnetic resonance temperature measurement image includes one, two or more of radio frequency, focused ultrasound and microwave.

[0074] Step S202, obtaining the steady-state time and the steady-state temperature of the target tissue from the instantaneous temperature.

[0075] Formula [1] can be solved by the Finite-Difference Time-Domain Method (FDTD) to obtain the temperature of each part of the tissue after cooling. The results are shown in Figure 3 As shown in the figure, the prostate is partially cooled and the reference temperature is lower than 37°C. The target position is determined by interaction with the user, and then the initial temperature (i.e., reference temperature) corresponding to φ0 in the following formula [2] and the phase corresponding to the initial temperature are determined to realize the calculation of the initial phase of magnetic resonance temperature measurement.

[0076] Example 2

[0077] Based on Example 1, see Figure 1 This embodiment provides a method for obtaining the magnetic resonance heating temperature of a target tissue. Compared with Embodiment 1, this method further includes the following steps:

[0078] Step S3, obtaining a magnetic resonance temperature measurement image of the region of interest.

[0079] Preferably, after obtaining the magnetic resonance temperature measurement image of the region of interest, filtering and averaging processing are also performed to optimize the imaging quality.

[0080] Step S4, obtaining the temperature change value of the magnetic resonance image according to the magnetic resonance temperature measurement image. Specifically, this step includes the following sub-steps:

[0081] Step S401, acquiring a phase map of a magnetic resonance temperature image.

[0082] Step S402: obtaining the phase change value of the region of interest through the phase map.

[0083] Step S403, obtain the temperature change value of the region of interest according to the phase change value. This step is implemented using the following formula:

[0084]

[0085] Where ΔT represents the temperature change, φ T represents the phase after temperature change, φ0 represents the phase corresponding to the steady-state temperature, γ represents the gyromagnetic ratio, which is 42.576 MHz / T in this embodiment, α represents the temperature sensitivity coefficient, which is 0.01 ppm / °C in this embodiment, B0 represents the magnetic field intensity, and TE represents the echo time of the gradient echo sequence.

[0086] Step S5, obtaining the magnetic resonance heating temperature of the target tissue according to the temperature change value and the steady-state temperature.

[0087] In the actual measurement process, when performing magnetic resonance temperature measurement based on formula [1], phase data of 1-2 time frames are usually collected before heating as the phase corresponding to the reference temperature. Subsequently, scanning is performed continuously during the heating process to collect phase data during the temperature change process, and the data is substituted into formula [2] for calculation to achieve continuous temperature measurement.

[0088] This method constructs the three-dimensional spatial position of the prostate and the cooling water bag, and performs bioheat transfer simulation based on the Pennes equation to determine the baseline temperature of the prostate after cooling during treatment, thereby achieving accurate temperature measurement during focused ultrasound transrectal ablation of prostate lesions. It has the following advantages:

[0089] (1) High accuracy of temperature measurement: In magnetic resonance temperature measurement, the phase corresponding to the reference temperature is determined while taking into account the structures that affect the physiological body temperature. This solves or partially solves the problem of temperature measurement errors caused by inaccurate reference phase of PRF under non-physiological body temperature conditions.

[0090] (2) Simple interaction: It is only necessary to manually mark the target tissue and the structure that affects the physiological body temperature before measurement, and select the target position on the target tissue as the reference during measurement. The interaction is simple.

[0091] (3) Wide application: It can be used for intraoperative and / or non-operative temperature measurement of various tissues.

[0092] It should be noted that applying the initial phase calculation method of magnetic resonance temperature measurement under non-physiological body temperature conditions to ablation therapy is only one application of this method. This temperature measurement method can also be applied to magnetic resonance temperature measurement under other non-physiological body temperature conditions, such as temperature measurement of tissues in colonoscopy and gastroscopy.

[0093] Example 3

[0094] Based on the above embodiments, this embodiment provides a method for obtaining a magnetic resonance temperature time domain curve, including:

[0095] The method for obtaining the magnetic resonance heating temperature of the target tissue as described in Example 2;

[0096] A time domain magnetic resonance heating temperature curve is obtained according to the time domain model and the instantaneous magnetic resonance heating temperature of the target tissue.

[0097] Among them, the time domain model can be implemented using an existing model.

[0098] Example 4

[0099] See also Figure 4 Based on the above-mentioned embodiment, this embodiment provides a device 100 for implementing the above-mentioned method for obtaining the steady-state temperature of a target tissue affected by the physiological temperature of the medium, comprising:

[0100] The influencing mechanism 110 is connected to the target tissue and is used to influence the physiological temperature of the target tissue. In this embodiment, the influencing mechanism includes a water bag, a focused ultrasonic transducer and a medium, the medium includes a liquid and a crystal, and the target tissue includes a prostate and a breast. The water bag includes a sound-permeable membrane, which encloses a closed space. There is a coolant in the closed space, and there is a temperature difference between the liquid temperature of the coolant and the physiological body temperature; the ultrasonic transducer is located in the coolant, and the coolant is used to achieve heat dissipation of the ultrasonic transducer and coupling of the sound path during ultrasonic propagation.

[0101] The three-dimensional modeling mechanism 120 is used to obtain magnetic resonance images of the region of interest of the impact mechanism 110 and the target tissue and construct a three-dimensional model.

[0102] The steady-state temperature acquisition mechanism 130 is connected to the three-dimensional modeling mechanism 120 and is used to obtain the steady-state temperature of the target tissue based on the three-dimensional model and the biological heat transfer model.

[0103] When the target tissue is wrapped in the medium, the physiological temperature of the target tissue will rise or fall sharply. It takes a certain amount of time for the temperature to balance, and it is no longer the normal physiological body temperature of 37°C. If the normal temperature is used for calculation, the reference temperature during magnetic resonance temperature measurement will be inaccurate. The above device achieves the accuracy of the target tissue reference temperature measurement, and no longer uses the normal 37°C, solving the problem that the magnetic resonance device cannot measure the reference temperature.

[0104] Example 5

[0105] See also Figure 5 Based on the above-mentioned embodiment, this embodiment provides a system for obtaining the magnetic resonance heating temperature of a target tissue, comprising:

[0106] The device 100 for acquiring the steady-state temperature of a target tissue in which the medium affects the physiological temperature as described in Example 4;

[0107] The temperature change acquisition device 200 is connected to the steady-state temperature acquisition device 100 and is used to acquire the temperature change value of the magnetic resonance image according to the magnetic resonance temperature measurement image;

[0108] The magnetic resonance temperature acquisition device 300 is connected to the steady-state temperature acquisition device 100 and the temperature change acquisition device 200, and is used to obtain the magnetic resonance heating temperature of the target tissue according to the temperature change value and the steady-state temperature.

[0109] Furthermore, in magnetic resonance temperature measurement, the phase corresponding to the reference temperature is determined under the premise of a structure that affects physiological body temperature, thereby solving the problem of temperature measurement error caused by inaccurate reference phase of PRF under non-physiological body temperature conditions.

[0110] Furthermore, it is only necessary to manually or automatically mark the target tissue and the structure that affects the physiological body temperature before measurement, and select the target position on the target tissue as a reference during measurement, and the interaction is simple.

[0111] Example 6

[0112] The present embodiment provides a computer-readable storage medium, including one or more programs for execution by one or more processors of an electronic device, wherein the one or more programs include instructions for executing a method for acquiring a steady-state temperature of a target tissue affected by the physiological temperature of the aforementioned medium, a method for acquiring a magnetic resonance heating temperature of a target tissue, or a method for acquiring a magnetic resonance temperature time domain curve.

[0113] The various embodiments of the present invention are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0114] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for obtaining the steady-state temperature of a target tissue in which a medium affects physiological temperature, characterized in that: Applied to a computer, the method comprises the following steps: obtaining a three-dimensional model of the magnetic resonance image of the region of interest; After the physiological temperature is affected by the medium, the steady-state temperature of the target tissue is obtained based on the three-dimensional model and the bioheat transfer model.

2. The method for obtaining the steady-state temperature of a target tissue in which a medium affects physiological temperature according to claim 1, characterized in that: A method for obtaining a three-dimensional model of a magnetic resonance image of a region of interest, comprising: acquiring magnetic resonance images of one, two or more time frames; Acquire a magnetic resonance image of the region of interest from the magnetic resonance image, wherein the magnetic resonance temperature measurement image of the region of interest includes a regional image of a target tissue and an influencing structure, wherein the influencing structure is a structure that affects the physiological temperature of the target tissue; A spatial model is constructed based on the magnetic resonance image.

3. The method for obtaining the steady-state temperature of a target tissue in which a medium affects physiological temperature according to claim 2, characterized in that: The method for constructing a spatial model comprises: On the magnetic resonance image, the target tissue and the affected structure are identified and marked, and a spatial model is constructed.

4. The method for obtaining the steady-state temperature of a target tissue in which a medium affects physiological temperature according to claim 1, characterized in that: The method for obtaining the steady-state temperature of the target tissue based on the bioheat transfer model comprises: Acquire several instantaneous temperatures of target tissues in continuous time; A steady-state time and a steady-state temperature of the target tissue are obtained from the instantaneous temperature.

5. The method for obtaining the steady-state temperature of a target tissue in which a medium affects physiological temperature according to claim 4, characterized in that: The method for obtaining several instantaneous temperatures of a target tissue in a continuous time includes: Among them, ρ t represents the density of the target tissue, c t represents the specific heat capacity of the target tissue, k represents the thermal conductivity of the target tissue, and ρ b represents the density of blood, c b represents the specific heat capacity of blood, ω b represents the blood perfusion rate, represents the change of instantaneous temperature in space with time, represents the blood temperature, Q meta , Q ext They represent the heat deposited at the focus by metabolic heat source and external heat source respectively.

6. The method for obtaining the steady-state temperature of a target tissue in which a medium affects physiological temperature according to claim 1, characterized in that: The structure affecting physiological temperature includes a water bag, a focused ultrasound transducer and a medium, wherein the medium includes liquid and crystal, and the target tissue includes a prostate and a breast.

7. A method for obtaining the magnetic resonance heating temperature of a target tissue, characterized in that: include: obtaining a three-dimensional model of the magnetic resonance image of the region of interest; After the physiological temperature is affected by the medium, the steady-state temperature of the target tissue is obtained based on the three-dimensional model and the bioheat transfer model; Acquiring a magnetic resonance temperature measurement image of the region of interest; According to the magnetic resonance temperature measurement image, obtaining a temperature change value of the magnetic resonance image; The magnetic resonance heating temperature of the target tissue is obtained according to the temperature change value and the steady-state temperature.

8. The method for obtaining the magnetic resonance heating temperature of a target tissue according to claim 7, characterized in that: The external heat source of the magnetic resonance temperature measurement image includes one, two or more of radio frequency, focused ultrasound and microwave.

9. The method for obtaining the magnetic resonance heating temperature of a target tissue according to claim 7, characterized in that: The method for obtaining the temperature change value of the magnetic resonance image according to the magnetic resonance temperature measurement image comprises: acquiring a phase map of a magnetic resonance temperature image; Acquire the phase change value of the region of interest through the phase map; A temperature change value of the region of interest is obtained according to the phase change value.

10. The method for obtaining the magnetic resonance heating temperature of a target tissue according to claim 9, characterized in that: The method for obtaining a temperature change value of an area of ​​interest according to the phase change value comprises: Among them, ΔT represents the temperature change value, φ T represents the phase after temperature change, φ0 represents the phase corresponding to the steady-state temperature, γ represents the gyromagnetic ratio, α represents the temperature sensitivity coefficient, B0 represents the magnetic field intensity, and TE represents the echo time of the gradient echo sequence.

11. A method for acquiring a magnetic resonance temperature time domain curve, characterized in that: include: The method for obtaining the magnetic resonance heating temperature of a target tissue according to any one of claims 7 to 10; A time domain magnetic resonance heating temperature curve is obtained according to the time domain model and the instantaneous magnetic resonance heating temperature of the target tissue.

12. A device for implementing the method for obtaining the steady-state temperature of a target tissue affected by the physiological temperature of a medium as claimed in any one of claims 1 to 6, characterized in that: include: An influencing mechanism, connected to the target tissue, and used to influence the physiological temperature of the target tissue; A three-dimensional modeling mechanism, used to obtain magnetic resonance images of the influencing mechanism and the region of interest of the target tissue, and construct a three-dimensional model; The steady-state temperature acquisition mechanism is connected to the three-dimensional modeling mechanism and is used to obtain the steady-state temperature of the target tissue based on the three-dimensional model and the biological heat transfer model.

13. A system for obtaining magnetic resonance heating temperature of a target tissue, characterized in that: include: The device for acquiring the steady-state temperature of a target tissue whose physiological temperature is affected by a medium as claimed in claim 12; a temperature change acquisition device, connected to the steady-state temperature measurement device, for acquiring a temperature change value of the magnetic resonance image based on the magnetic resonance temperature measurement image; The magnetic resonance temperature acquisition device is connected to the steady-state temperature measurement device and the temperature change acquisition device, and is used to obtain the magnetic resonance heating temperature of the target tissue according to the temperature change value and the steady-state temperature.

14. A computer-readable storage medium, characterized in that: It comprises one or more programs for execution by one or more processors of an electronic device, wherein the one or more programs include instructions for executing a method for acquiring a steady-state temperature of a target tissue in which a medium affects a physiological temperature as described in any one of claims 1 to 6.

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