Osteoid osteoma microwave ablation thermal injury assessment method based on all-optical parameters

Abstract

The invention discloses a bone-like osteoma microwave ablation thermal injury assessment method based on all-optical parameters, which comprises the following steps: respectively considering thermal injury models of cortical bone and cancellous bone under different microwave ablation conditions by constructing a simulation model conforming to bone tissue characteristics; according to the method, construction of an incomplete P5 approximation model is proposed, bone tissue all-optical parameter anti-construction research based on steady-state radiance is carried out, the accuracy is high, calculation is convenient, temperature parameters and biological tissue all-optical parameters are analyzed in a combined mode, a tissue thermal damage model of the temperature and tissue all-optical parameters is established through theoretical research, and due to the characteristics of different bone tissues, the tissue thermal damage model can be used as a tissue thermal damage model of the temperature and tissue all-optical parameters. The tissue types are considered in the thermal damage model, and effective bone tissue thermal damage factors are designed based on different tissues, so that the evaluation accuracy is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave ablation treatment of osteoid osteoma, and particularly relates to a method for evaluating thermal damage of microwave ablation of osteoid osteoma based on full optical parameters. BACKGROUND

[0002] Minimally invasive microwave tumor thermal ablation treatment has been gradually applied to the treatment of osteoid osteoma due to its obvious curative effect and small side effects, but there are still some core scientific problems that need to be solved, such as the inability to conveniently, accurately and in real time obtain tissue thermal damage information during surgery, which mainly relies on the experience of doctors and preoperative image spatial position information for surgery at present, and the thermal radiation in the surgical process has the risk of damaging adjacent tissues and skin, but these information can only be obtained through postoperative image data, and the clinical curative effect is mainly evaluated by central temperature monitoring, which inevitably affects the surgical effect; there is a lack of accurate and effective real-time curative effect evaluation factor for microwave thermal ablation, and it is difficult to obtain dynamic temperature field in clinical practice, and real-time temperature cannot accurately reflect the ablation degree of tumor tissue, and the final ablation effect depends on the thermal ablation dose: power and time, but the dose still cannot describe the real-time thermal damage of the tissue, and it is difficult to realize accurate real-time curative effect evaluation during surgery, thereby affecting the microwave ablation treatment effect. SUMMARY

[0003] Technical purpose: in view of the deficiencies of the existing microwave ablation of osteoid osteoma, the present application discloses a method for evaluating thermal damage of microwave ablation of osteoid osteoma based on full optical parameters.

[0004] Technical scheme: in order to achieve the above technical purpose, the present application adopts the following technical scheme:

[0005] A method for evaluating thermal damage of microwave ablation of osteoid osteoma based on full optical parameters, comprising the following steps:

[0006] S01, microwave ablation experiment is carried out, non-isothermal heating method is used for thermal damage treatment experiment of simulation tissue, and temperature parameters and steady-state emissivity parameters of microwave ablation are obtained;

[0007] S02, full optical parameter inverse construction is carried out based on the steady-state emissivity parameters, absorption coefficient, scattering coefficient and anisotropy factor are obtained;

[0008] S03, the thermal damage degree of the simulation tissue is quantitatively analyzed based on the Arrhenius thermal damage model, the correlation between the absorption coefficient, the scattering coefficient and the anisotropy factor and the thermal damage degree is obtained by using the multiple regression analysis method, the thermal damage factor related to the full optical parameters is determined, the thermal damage model is established through the thermal damage factor, the input of the thermal damage model is the temperature parameter and the steady-state emissivity, and the output is the tissue type and the thermal damage degree of the tissue; the thermal damage degree of microwave ablation is evaluated by using the thermal damage model.

[0009] Preferably, in the full optical parameter reconstruction based on the steady-state radiance parameter, the application uses the steady-state radiance P5 approximation model to analyze the full optical parameters of the experiment, sets the radiance measurement source probe on the simulated tissue, measures 30 degrees, 60 degrees, 90 degrees, 120 degrees, 140 degrees and 170 degrees at each radiance measurement source probe, obtains the radiance measurement value at the six angles, and calculates the full optical parameters based on the radiance measurement value.

[0010] Preferably, the application uses a two-dimensional flat plate model to derive the P5 approximation expression of the steady-state radiance, and finally obtains the P5 expression of the radiance under the three-dimensional spherical symmetry model according to the coordinate relationship between the two-dimensional flat plate symmetry and the three-dimensional spherical symmetry.

[0011] Preferably, in the full optical parameter analysis of the experiment based on the steady-state radiance P5 approximation model, the temperature distribution generated in the microwave ablation process is set for the radiance measurement source probe.

[0012] Preferably, the temperature distribution generated in the microwave ablation process includes: S001, establishing a microwave ablation needle geometric model and a bone tissue geometric model;

[0013] S002, based on the transmission and heat conduction of microwaves in biological tissues, a microwave ablation simulation model covering cancellous bone, cortical bone and double-layer bone tissue is established;

[0014] S003, the microwave ablation simulation model is meshed in COMSOL, the simulation parameters are set for bone tissue heating, the model is solved using a time domain solver, and the temperature distribution in the microwave ablation simulation model of cancellous bone, cortical bone and double-layer bone tissue at different times is obtained;

[0015] S004, based on the temperature distribution, the microwave ablation needle is taken as the center point, the radiance measurement source probe is arranged in the temperature distribution range, and near-infrared radiation and temperature detection are performed through the probe.

[0016] Preferably, the microwave ablation needle geometric model is constructed based on the structure of a 2450MHz microwave ablation needle used in clinical application, the front part of the needle body mainly consists of a microwave coaxial cable, a needle body sleeve, a puncture needle and a polytetrafluoroethylene insulating medium sleeve; the bone tissue shape is set as a cylindrical shape, and the microwave ablation needle and the bone tissue geometric model are simplified as an axisymmetric structure.

[0017] Preferably, in the simulation calculation of the present application, the boundary conditions of the simulation model can be defined according to the physical model of electromagnetic wave transmission and biological tissue heat conduction, the initial temperature of bone tissue in the model and the water-cooled constant temperature boundary are set to 37 DEG C, the microwave power in the simulation model is set to 50W, different heating times are set, and the simulation results under different heating conditions are obtained.

[0018] Beneficial effects: the bone-like osteoma microwave ablation heat damage evaluation method based on full optical parameters has the following beneficial effects:

[0019] 1. The present application is based on the research of radiation transmission theory, and proposes a residual P5 approximate model construction, and carries out the bone tissue full optical parameter inverse construction based on the steady-state radiation rate, which is high in accuracy and convenient to calculate.

[0020] 2. The present application constructs a microwave ablation simulation model of different bone tissues based on the heat damage theory, and the temperature rise and heat damage caused by microwave ablation will cause changes in tissue optical property parameters, blood oxygen parameters, etc., and the difference in porosity and density between cortical bone and cancellous bone is very large, resulting in obvious distinction in various parameters of them, and the heat damage conditions of cortical bone and cancellous bone under different microwave ablation conditions are considered respectively, and the simulation results lay a theoretical foundation for the research of bone tissue heat damage model.

[0021] 3. The present application combines temperature parameters and biological tissue full optical parameters for analysis, and establishes a tissue heat damage model of temperature and tissue full optical parameters through theoretical research, and due to the characteristics of different bone tissues, the tissue type is considered in the heat damage model, and effective bone tissue heat damage factors are designed based on different tissues, and the construction of different models is conducive to improving the evaluation accuracy, and lays a foundation for the design of individualized treatment plan of bone-like osteoma. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description.

[0023] Figure 1 The simulation result diagram of cancellous bone microwave ablation of the present application;

[0024] Figure 2 The probe arrangement schematic diagram of the present application;

[0025] Figure 3 The radiation rate measurement schematic diagram of the radiation rate measurement source probe point of the present application;

[0026] Figure 4 The bone-like osteoma model schematic diagram constructed by the microwave ablation experiment of the present application. DETAILED DESCRIPTION

[0027] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are set forth herein below. Each embodiment and example is provided by way of explanation of the present disclosure, not limitation. It will be apparent to those of ordinary skill in the art that various modifications and variations can be made to the present disclosure without departing from the scope or spirit of the present disclosure. Thus, it is intended that the present disclosure cover all such modifications and variations as fall within the scope of the present disclosure.

[0028] The application discloses a method for evaluating microwave ablation heat damage of osteoid osteoma based on full optical parameters, comprising the following steps:

[0029] S01, microwave ablation experiment is carried out, non-isothermal heating method is used for heat damage treatment experiment of simulation tissue, and temperature parameters and steady-state radiation rate parameters of microwave ablation are obtained;

[0030] The microwave ablation equipment adopts a microwave ablation instrument and an ablation needle commonly used in clinical treatment, the needle body has a length of 15 cm, an outer diameter of 1.9 mm, and a working frequency of 2450 MHz, and has a water circulation cooling function. The probe is inserted into the tissue for testing, the steady-state radiation rate is collected by a computer, and after calculation, the full optical parameters (scattering coefficient, absorption parameter, anisotropy factor) and temperature parameters of the biological tissue can be obtained.

[0031] As shown in Figure 4 The simulation tissue uses a fresh isolated pig leg to establish an osteoid osteoma model, and when the simulation tissue is manufactured, first, the proximal joint of the femur of the fresh pig leg is sawn off by using an electric saw, the cortical transverse section of the femoral shaft is exposed, and then the thick cortical part is selected on the transverse section to make the model. A cylindrical bone channel with a diameter of 2 mm and a length of 2 cm is drilled in the cortical bone of the femur parallel to the long axis of the femur at a position 2 mm away from the cortical surface of the pig femur by using an electric drill with a drill bit with a diameter of 2 mm, to simulate the osteoid osteoma of the long bone. After the modeling is completed, the model is fixed by using a plastic support, and is placed in a water basin containing 37-degree constant-temperature physiological saline, so that the temperature of the model tissue gradually reaches 37 DEG C to simulate the body temperature in the human body.

[0032] After the osteoid osteoma model in the bone is established, the microwave treatment probe and the probe are inserted along the bone channel in parallel, so that the tips of the probe and the probe are located at the bottom of the cylindrical bone channel at the same time, and a small amount of soft tissue is used to seal the bone channel opening, so that the environment in the tumor nest of the osteoid osteoma model is closer to the environment in the tumor nest of the real human osteoid osteoma. After the preparation work is completed, the microwave source is adjusted for the experiment.

[0033] Different microwave powers are selected for multiple experiments, for example, the power output is selected as 50W, and parameters such as temperature and steady-state emissivity are monitored in real time; after each experiment, bone tissue is taken at the probe, and CT influence analysis is performed. Different ablation times are selected for multiple experiments, the microwave power output column in the microwave treatment control software is adjusted to the power output state, the microwave output power is gradually increased, the temperature curve is smoothly increased, for example, when the model tumor nest center temperature is gradually heated to 900 degrees Celsius, the microwave output power is kept unchanged, the tumor nest center temperature is kept at 900 degrees Celsius for 10 minutes, the temperature, steady-state emissivity and other parameters are monitored in real time, after each experiment, bone tissue is taken at the probe, and CT influence analysis is performed

[0034] S02, based on the steady-state emissivity parameter, the full optical parameter is inversely constructed, and the absorption coefficient, the scattering coefficient and the anisotropy factor are obtained

[0035] When the full optical parameter is inversely constructed based on the steady-state emissivity parameter, the full optical parameter is analyzed based on the steady-state emissivity residual P5 approximate model, the emissivity measurement source probe is set on the simulation tissue, and the emissivity measurement values L at six angles of 30 degrees, 60 degrees, 90 degrees, 120 degrees, 140 degrees and 170 degrees are measured at each emissivity measurement source probe, as shown in Figure 3 S0 represents the center point of the microwave ablation needle, the probes are arranged at distances r1 and r2 from the center point, respectively, the corresponding emissivity measurement values L at six angles are obtained, and the full optical parameters are calculated based on the emissivity measurement values.

[0036] Among them, the absorption effect and the scattering effect exist in most biological tissue bodies, and the scattering effect is dominant, based on the determination model, the expression of the corresponding radiation transfer equation can be determined L represents the emissivity, and the physical meaning is the energy flow per unit area per unit solid angle at position r along direction s, μ t is the attenuation coefficient, μ s is the scattering coefficient, is a phase function, the left side of the equation represents the change rate of the photon beam along its propagation direction, and the rightmost side of the equation represents the deviation of the photon beam direction caused by scattering. The radiation transfer equation is a very complex integral equation, which is difficult to solve directly, and the approximate solution or numerical solution is usually calculated.

[0037] The P5 approximate expression of the steady-state emissivity is derived using a two-dimensional flat plate model, and the P5 expression of the emissivity under the three-dimensional spherical symmetry model is finally obtained according to the coordinate relationship between the two-dimensional flat plate symmetry and the three-dimensional spherical symmetry. Under the condition of the flat plate model, the physical quantity emissivity is only related to the z-axis space variable and the angle.

[0038] In the parallel model, the emissivity L(z, η), the light source S(z, η), and the phase function are... Using Legendre polynomial P l Expanding (η) and taking the first six terms, as follows:

[0039]

[0040] Substituting the Hermite-Gaussian phase functions into formula (1), g is obtained through calculation. l =g l Substitute equation (1) into the radiative transfer equation, and multiply both sides of the equation by P. l (η) and integrate. Based on the orthogonality of Legendre polynomials, the radiative transfer equation can be transformed into a system of first-order differential equations:

[0041]

[0042] For the P5 approximation, let l < 5, and the Legendre moments of each term are 0. The first six terms of equation (2) can be written as equation (3).

[0043] μ a φ0+φ1′=q0

[0044]

[0045] Within the tissue region, the Legendre moments of each order of emissivity satisfy the homogeneous equations of formula (3). According to the plane wave method, the solution to the homogeneous equations in formula (3) is assumed to be:

[0046]

[0047] Substituting formula (4) into the homogeneous system of equations corresponding to formula (3) and simplifying, we get the following formula (5).

[0048] μ a B0+vB1=0

[0049] vB0+3σ1B1+2vB2=0

[0050] 2vB1 + 5σ2B2 + 3vB3 = 0

[0051] 3vB² + 7σ³B³ + 4vB⁴ = 0

[0052] 4vB3+9σ4B4+5vB5=0

[0053] 5vB4+11σ5B5=0 (5)

[0054] Solve for B using formula (5) lThe determinant of the coefficient matrix in formula (5) is 0, therefore B l In the sequence (l = 0, ..., 5), one variable is a free variable. Assuming B0 is a free variable, we can solve for B. l / B0(l=0,...5), and defined as h l (v)(l=0,...5), there is formula (6).

[0055]

[0056] Based on equation (6), the expressions for the other parameters can be derived:

[0057] σ0=μ a =h1(v)·v

[0058]

[0059] The scattering coefficient μ can be obtained from the definitions of σ1 and σ2. s The expression for each anisotropic factor g is given by equation (8).

[0060]

[0061] Absorption coefficient μ of all optical parameters a scattering coefficient μ s The anisotropy factor g can be calculated using the effective attenuation coefficients v, h1, h2, and h3, as shown in equation (9).

[0062] μ a =h1·v

[0063]

[0064] The problem of reconstructing the total optical parameters is transformed into the problem of extracting v, h1, h2, and h3 from the emissivity measurements at different source distances and angles. The total optical parameters can be calculated directly by measuring the emissivity at each source point.

[0065] When performing full optical parameter analysis for experiments using the residual P5 approximation model based on steady-state emissivity, this invention sets the temperature distribution generated during microwave ablation of the emissivity measurement source probes. Based on the temperature distribution range, the measurement range is determined, and then the corresponding number of probes is determined based on the spacing between the emissivity measurement source probes.

[0066] The process of temperature distribution generated during microwave ablation in this invention includes: S001, establishing a geometric model of the microwave ablation needle and a geometric model of bone tissue;

[0067] S002. Based on the transport and heat conduction of microorganisms in biological tissues, establish a microwave ablation simulation model covering cancellous bone, cortical bone and double-layered bone tissue;

[0068] S003. In COMSOL, the microwave ablation simulation model is meshed, simulation parameters are set for bone tissue heating, and a time-domain solver is used to solve the model. The temperature distribution of cancellous bone, cortical bone, and double-layer bone tissue within the microwave ablation simulation model at different time points is obtained. This invention... Figure 1 This is a schematic diagram of the simulation results of microwave ablation of cancellous bone.

[0069] S004, Based on temperature distribution, such as Figure 2 As shown, with the location of the microwave ablation needle as the center point, probes are arranged at the emissivity measurement source points within the temperature distribution range to perform near-infrared radiation and temperature detection.

[0070] The geometric model of the microwave ablation needle in this invention is based on the structure of the 2450MHz microwave ablation needle used in clinical applications. The front part of the needle body is mainly composed of a microwave coaxial cable, a needle body sheath, a puncture needle tip, and a polytetrafluoroethylene insulating dielectric sheath. The bone tissue shape is set as cylindrical, and the geometric model of the microwave ablation needle and bone tissue is simplified to an axisymmetric structure.

[0071] In the simulation calculation of this invention, the boundary conditions of the simulation model can be defined according to the physical models of electromagnetic wave transmission and biological tissue heat conduction. The initial temperature of bone tissue and the water-cooled isothermal boundary in the model are set to 37°C, the microwave power in the simulation model is set to 50W, and different heating times are set to obtain simulation results under different heating conditions.

[0072] The propagation of microwaves within biological tissues is typically solved using the electromagnetic wave propagation equation in a lossy conductive medium, where the electric field wave equation is:

[0073]

[0074] Where μ is the magnetic permeability, in H·m -1 γ is the conductivity, in S·m -1 ε is the dielectric constant, in F·m. -1 The absorption of microwaves by tissues can be expressed by the absorptivity (SAR):

[0075]

[0076] Where ρ is the tissue density, with units of kg·m³. -3 Let |E| represent the root mean square of the magnitudes of the components of the electric field in each direction. Then, the unit of SAR is W·kg. -1 In the simulation model, SAR characterizes the absorption of microwave energy per unit mass of tissue and its conversion into heat.

[0077] The absorption and heat transfer analysis of wave energy was solved using a biological tissue heat conduction model (Pennes equations). The external heat source term Qext was transformed according to the SAR definition.

[0078]

[0079] The above equation represents the absorption of microwave energy by the tissue, which is the external heat source for tissue heat conduction. This also serves as the bridge for coupling the biological tissue heat conduction model with the electromagnetic wave transmission model. To accurately reflect the influence of the ablation needle tip on the heat conduction of the central ablation region and the cooling effect of water circulation on the needle body, the thermal conductivity effect of the emitter and insulating medium in the simulation model is analyzed using the solid-state heat conduction equation:

[0080]

[0081] Where ρ is density, in kg·m -3 C represents specific heat capacity, measured in J·kg⁻¹. -1 ·K -1 k is thermal conductivity, in W·m -1 ·K -1 Q represents the heat source term, in W·m³. -3 A simplified isothermal boundary condition is used in the water-cooled portion of the needle body to describe the effect of cooling water on the ablation zone, thereby improving the accuracy of heat conduction analysis in the ablation center region.

[0082] S03. Based on the Arrhenius thermal damage model, the degree of thermal damage to simulated tissue is quantitatively analyzed. The correlation between absorption coefficient, scattering coefficient and anisotropy factor and the degree of thermal damage is obtained by using multiple regression analysis. The thermal damage factor related to the total optical parameters is determined. A thermal damage model is established through the thermal damage factor. The input of the thermal damage model is temperature parameter and steady-state emissivity. The output is tissue type and degree of thermal damage. The thermal damage model is used to evaluate the degree of thermal damage from microwave ablation.

[0083] The Arrhenius thermal damage model based on chemical reaction kinetics can be used to describe thermal damage to biological tissues. It assumes that the thermal damage process of biological tissues is a first-order chemical reaction of a single reactant, and that the reaction rate is related to temperature. The accumulation of thermal damage depends on the temperature and time of the tissue.

[0084] Thermal damage is quantitatively described by the thermal damage factor Ω, which changes at a rate of dΩ / dt. Therefore, the cumulative thermal damage over time t is: Where A is the pre-exponential factor (or frequency factor), in units of s. -1 E a The activation energy is expressed in J·mol⁻¹. -1R is the gas constant, 8.3143, in J·mol⁻¹ -1 ·K -1 T represents absolute temperature, measured in Kelvin (K).

[0085] The entire process of tissue thermal damage is described as the integral of the damage factor Ω, a process determined by A and E. a Two parameters determine this. When using a non-isothermal heating method to perform thermal damage treatment on tissue, the temperature changes over time, and we can obtain:

[0086]

[0087] Taking the logarithm of both sides of the above equation, we get

[0088]

[0089] Define function Then there is,

[0090]

[0091] In the non-isothermal heating process, Φ(T,t) is a space curve whose projection onto the plane Φ⁻¹ / T is a straight line with a slope of -E. a / R, with intercept lnA, can be used to solve for A and E by fitting this line. a The system calculates the tissue scattering coefficient, absorption coefficient, and anisotropy factor in real time from the collected steady-state emissivity after acquiring temperature and total optical parameters. The value of the function Φ(T, t) can be calculated through curve fitting. A straight line projecting Φ(T, t) onto the Φ-1 / T plane is constructed using this function, which varies with temperature T. The thermal damage factor Ω is then fitted using the slope and intercept of this line.

[0092] The thermal damage model expression is: (h α (D) = Ψ(Ω, X1, X2, X3, Y), where hα refers to the bone tissue type (cancellous bone or compact bone), D is the degree of tissue thermal damage, X1 represents the tissue absorption coefficient, X2 represents the scattering coefficient, X3 represents the anisotropy factor, Y represents the tissue temperature parameter, Ω represents the thermal damage factor, and E a Related to A.

[0093] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for assessing microwave ablation thermal lesion of osteoid osteoma based on full optical parameters, characterized in that, The method comprises the steps of: S01, microwave ablation experiment is carried out, non-isothermal heating method is used for heat damage treatment experiment of simulation tissue, temperature parameters and steady-state radiation parameters of microwave ablation are obtained; S02, full optical parameter reconstruction is carried out based on the steady-state radiation parameters, the absorption coefficient, the scattering coefficient and the anisotropy factor are obtained; S03, the degree of heat damage of the simulation tissue is quantitatively analyzed based on the Arrhenius heat damage model, the correlation between the absorption coefficient, the scattering coefficient and the anisotropy factor and the degree of heat damage is obtained by using the multiple regression analysis method, the heat damage factor related to the full optical parameters is determined, the heat damage model is established through the heat damage factor, the input of the heat damage model is the temperature parameters and the steady-state radiation, and the output is the type of tissue and the degree of heat damage of the tissue; The heat damage model is used for evaluating the degree of heat damage in microwave ablation.

2. The all-optical parameter based osteoid osteoma microwave ablation thermal lesion assessment method of claim 1, wherein, When the full optical parameter reconstruction is carried out based on the steady-state radiation parameters, the P5 approximate model based on the incomplete steady-state radiation is used for experimental full optical parameter analysis, the radiation measurement source probe points are set on the simulation tissue, the radiation measurement values at six angles of 30 degrees, 60 degrees, 90 degrees, 120 degrees, 140 degrees and 170 degrees are obtained, and the full optical parameters are calculated based on the radiation measurement values.

3. The all-optical parameter based osteoid osteoma microwave ablation thermal lesion assessment method of claim 2, wherein, The P5 approximate expression of the steady-state radiation is derived by using a two-dimensional flat plate model, and the P5 expression of the radiation under the three-dimensional spherical symmetry model is finally obtained according to the coordinate relationship between the two-dimensional flat plate symmetry and the three-dimensional spherical symmetry.

4. The method of assessing microwave ablation thermal lesion of osteoid osteoma based on full optical parameters according to claim 2, characterized in that, When the full optical parameter analysis is carried out by using the P5 approximate model based on the incomplete steady-state radiation, the temperature distribution generated in the microwave ablation process is set for the radiation measurement source probe points.

5. The all-optical parameter based osteoid osteoma microwave ablation thermal lesion assessment method of claim 4, wherein, The temperature distribution generated in the microwave ablation process comprises the following steps: S001, a microwave ablation needle geometric model and a bone tissue geometric model are established; S002, a microwave ablation simulation model covering cancellous bone, cortical bone and double-layer bone tissue is established based on the transmission and heat conduction of microwaves in biological tissue; S003, the microwave ablation simulation model is meshed in COMSOL, simulation parameters are set for bone tissue heating, a time domain solver is used for model solving, and the temperature distribution in the microwave ablation simulation model of cancellous bone, cortical bone and double-layer bone tissue at different times is obtained; 6. The all-optical parameter based osteoid osteoma microwave ablation thermal lesion assessment method of claim 5, wherein, S004, based on the temperature distribution, the radiation measurement source probe points are arranged around the center point of the microwave ablation needle, near-infrared radiation and temperature detection are carried out through the probe. The microwave ablation needle geometric model is constructed based on the structure of a 2450MHz microwave ablation needle used in clinical application, the front part of the needle body mainly comprises a microwave coaxial cable, a needle body sleeve, a puncture needle and a polytetrafluoroethylene insulating medium sleeve; the bone tissue shape is set as a cylindrical shape, and the microwave ablation needle and the bone tissue geometric model are simplified as an axisymmetric structure.

7. The all-optical parameter based osteoid osteoma microwave ablation thermal lesion assessment method of claim 5, wherein, In the simulation calculation, the boundary conditions of the simulation model can be defined according to the physical models of electromagnetic wave transmission and biological tissue heat conduction, the initial temperature of the bone tissue in the model and the water-cooled constant temperature boundary are set to 37 DEG C, the microwave power in the simulation model is set to 50 W, different heating times are set, and the simulation results under different heating conditions are obtained.

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