阅读说明：本技术 一种用于肝肿瘤的微波消融治疗剂量的控制方法 (Control method of microwave ablation treatment dosage for liver tumor ) 是由 蔡惠明 钱志余 冯宇 方舟 晋晓飞 于 2020-06-23 设计创作，主要内容包括：本发明公开了一种用于肝肿瘤的微波消融治疗剂量的控制方法,包括以下步骤：S1、构建肝脏微波消融仿真模型；S2、根据实际肿瘤大小设置消融剂量即消融功率和消融时间,测温针距消融针旁开距离以及消融针、测温针的插入深度；S3、按设置好的消融剂量,完成仿真消融,同时获得相应旁开距离测温位点的温度实时变化数据；S4、将消融针与测温针按预设距离并排插入肿瘤组织中,开始实际消融；S5、按照预设消融剂量开始实际消融,进行相应的判断。该方法利用术前仿真和术中测温来建立更为准确的消融剂量反馈控制方案,根据参数不断修正消融结果,实现更好的治疗效果。(The invention discloses a control method of microwave ablation treatment dosage for liver tumor, which comprises the following steps: s1, constructing a liver microwave ablation simulation model; s2, setting ablation dosage, namely ablation power and ablation time, a temperature measuring needle and an ablation needle side-by-side distance and the insertion depth of the ablation needle and the temperature measuring needle according to the actual tumor size; s3, completing simulated ablation according to the set ablation dosage, and simultaneously obtaining real-time temperature change data of the temperature measurement sites of the corresponding side-by-side distances; s4, inserting the ablation needle and the temperature measuring needle into the tumor tissue side by side according to a preset distance, and starting actual ablation; and S5, starting actual ablation according to the preset ablation dosage and carrying out corresponding judgment. The method utilizes preoperative simulation and intraoperative temperature measurement to establish a more accurate ablation dosage feedback control scheme, and continuously corrects an ablation result according to parameters to realize a better treatment effect.)

1. A control method of microwave ablation treatment dosage for liver tumor is characterized in that: the method can feedback control the therapeutic dose of microwave ablation according to the temperature data obtained by the temperature measuring needle in the tumor ablation process and the temperature data of the same site in the simulated temperature field, and comprises the following steps:

s1, constructing a liver microwave ablation simulation model according to the size of an actual liver tumor, designing the geometric structures of an ablation needle and the liver by adopting a two-dimensional axisymmetric assembly, setting material parameters, and constructing an electromagnetic radiation model and a biological heat conduction model;

s2, setting ablation dosage, namely ablation power and ablation time, a temperature measuring needle and ablation needle side-by-side distance and the insertion depth of the ablation needle and the temperature measuring needle according to the actual tumor size;

s3, completing simulated ablation according to the set ablation dosage, and simultaneously obtaining real-time temperature change data of the temperature measurement sites of the corresponding side-by-side distances;

s4, inserting the ablation needle and the temperature measuring needle into the tumor tissue side by side according to a preset distance, ensuring that the ablation needle and the temperature measuring needle are positioned on the same plane, simultaneously connecting the ablation needle and the temperature measuring needle with a microwave ablation treatment system and a temperature measuring system, and starting actual ablation;

s5, starting actual ablation according to a preset ablation dosage, comparing the average value of the temperature measuring point on the temperature measuring needle with the average value of the temperature of the same point in simulation in real time every 15 seconds, feeding back and regulating the ablation dosage according to the result, keeping the ablation dosage unchanged if the result of subtracting the simulation temperature average value from the actual temperature average value is more than or equal to 0 and less than or equal to 15 ℃, and continuing to ablate until the end; if the difference between the actual temperature average value and the simulated temperature average value is larger than 15 ℃, reducing the ablation dosage to a preset ablation dosage, and continuing ablation; and if the simulation temperature average value minus the actual temperature average value is more than 15 ℃, increasing the ablation dosage to a preset ablation dosage, and continuing ablation.

2. The method for controlling microwave ablation treatment dosage for liver tumor according to claim 1, wherein the step S1 includes the following steps:

s11, selecting a two-dimensional axisymmetric component, and setting the length unit as mm;

s12, constructing a liver ablation model, which is mainly divided into a liver and an ablation needle body, wherein the ablation needle body comprises a puncture head, a stainless steel sleeve, a coaxial cable and an insulating medium sleeve, the coaxial cable comprises an inner conductor, an insulating medium and an outer conductor, the puncture head and the inner conductor of the coaxial cable are combined into a domain, the insulating medium and the insulating medium sleeve of the coaxial cable are combined into a domain, the liver is a domain, and the rest of the domain is set as an ideal electric conductor boundary, so that a two-dimensional axisymmetric model liver microwave ablation geometric figure is constructed;

s13, setting the parameters of material, electromagnetic radiation and biological heat conduction, such as constant pressure heat capacity Cp, heat conductivity к, density rho, and relative dielectric constant of liver_rConductivity σ, etc.

3. The method for controlling microwave ablation therapeutic dose for liver tumor according to claim 1, wherein the temperature measuring needle is a single-point temperature measuring needle, the temperature measuring point is at the needle tip, the ablation needle and the temperature measuring needle are inserted into the liver tissue on the same plane, and the side distance is the separation distance.

Technical Field

The invention relates to the field of medical treatment, in particular to a control method of microwave ablation treatment dosage for liver tumor.

Background

Currently, the setting of microwave thermal dose for a tumor of a specific shape and specific location is still largely dependent on the subjective judgment and clinical experience of the doctor. The temperature as a parameter directly reflecting the heat absorption of the tissue can provide important basis for the guiding of the heat treatment and the dosage control, and is widely used as an important reference for the evaluation of the tissue ablation result in clinic. In clinical treatment, a single-point temperature measuring needle is usually inserted to obtain temperature to evaluate the ablation curative effect, ablation simulation results under different microwave thermal doses are mainly displayed by a 2D/3D microwave ablation temperature field or a thermal injury field thereof, and during the ablation process, the thermal injury of tissues is the accumulation of temperature. In the microwave ablation process of tumors, in order to achieve the best treatment effect, the key is to monitor the temperature distribution of tissues in real time in the ablation process. The computer simulation of the temperature field is a non-invasive temperature measurement method, and the temperature field distribution in the whole ablation process can be obtained according to a thermal field model. Medical care personnel can visually know the treatment process and the treatment result under different microwave thermal doses before the microwave thermal ablation operation is carried out, and can correct the ablation result according to partial parameters to finally achieve the ideal treatment effect. Therefore, how to achieve a fully conformal ablation of a tumor, how to achieve an accurate control of the microwave thermal dose and a reliable simulation of the ablation result is a key issue in microwave hyperthermia.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a control method of microwave ablation treatment dosage for liver tumors, and the invention adopts the following technical scheme for solving the technical problems:

a control method for microwave ablation treatment dosage of liver tumor can feedback regulate and control treatment dosage of microwave ablation according to temperature data obtained by a temperature measuring needle in a tumor ablation process and temperature data of the same site in a simulation temperature field, and comprises the following steps:

s1, constructing a liver microwave ablation simulation model according to the size of an actual liver tumor, and designing the geometric structures of an ablation needle and the liver by adopting a two-dimensional axisymmetric assembly, setting material parameters, and setting an electromagnetic radiation model and a biological heat conduction model;

s2, setting ablation dosage, namely ablation power and ablation time, a temperature measuring needle and an ablation needle side-by-side distance and the insertion depth of the ablation needle and the temperature measuring needle according to the actual tumor size;

s3, completing simulated ablation according to the set ablation dosage, and simultaneously obtaining real-time temperature change data of the temperature measurement sites of the corresponding side-by-side distances;

s4, inserting the ablation needle and the temperature measuring needle into the tumor tissue side by side according to a preset distance, ensuring that the ablation needle and the temperature measuring needle are positioned on the same plane, simultaneously connecting the ablation needle and the temperature measuring needle with a microwave ablation treatment system and a temperature measuring system, and starting actual ablation;

s5, starting actual ablation according to a preset ablation dosage, comparing the average value of the temperature measuring point on the temperature measuring needle with the average value of the temperature of the same point in simulation in real time every 15 seconds, feeding back and regulating the ablation dosage according to the result, keeping the ablation dosage unchanged if the result of subtracting the simulation temperature average value from the actual temperature average value is more than or equal to 0 and less than or equal to 15 ℃, and continuing to ablate until the end; if the difference between the actual temperature average value and the simulated temperature average value is larger than 15 ℃, reducing the ablation dosage to a preset ablation dosage, and continuing ablation; and if the simulation temperature average value minus the actual temperature average value is more than 15 ℃, increasing the ablation dosage to a preset ablation dosage, and continuing ablation.

Preferably, the step S1 includes the following steps:

s11, selecting a two-dimensional axisymmetric component, and setting the length unit as mm;

s12, constructing a liver ablation model, which is mainly divided into a liver and an ablation needle body, wherein the ablation needle body comprises a puncture head, a stainless steel sleeve, a coaxial cable and an insulating medium sleeve, the coaxial cable comprises an inner conductor, an insulating medium and an outer conductor, the puncture head and the inner conductor of the coaxial cable are combined into a domain, the insulating medium and the insulating medium sleeve of the coaxial cable are combined into a domain, the liver is a domain, and the rest of the domain is set as an ideal electric conductor boundary, so that a two-dimensional axisymmetric model liver microwave ablation geometric figure is constructed;

s13, material parameters, electricitySetting of magnetic radiation parameters and biological heat conduction parameters, such as constant pressure heat capacity of liver Cp, heat conductivity к, density rho, and relative dielectric constant_rConductivity σ, etc.

Preferably, the temperature measuring needle is a single-point temperature measuring needle, the temperature measuring point is at the needle tip, the ablation needle and the temperature measuring needle are inserted into the liver tissue on the same plane, and the side distance is the spacing distance.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

the treatment dosage of microwave ablation is fed back and regulated according to the temperature data obtained by the temperature measuring needle in the tumor ablation process and the temperature data of the same site in the simulation temperature field, so that the microwave ablation treatment of the tumor is more accurate; a more accurate ablation dosage feedback control scheme is established by using preoperative simulation and intraoperative temperature measurement, and an ablation result is continuously corrected according to parameters, so that a better treatment effect is finally realized.

Drawings

Fig. 1 is a flowchart of a method for controlling a microwave ablation treatment dose for a liver tumor according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the application of the control method for microwave ablation treatment dosage of liver tumor to microwave thermal tumor ablation according to the embodiment of the present invention;

FIG. 3 is a diagram of an ablation needle and a liver simulation geometric model for a method for controlling microwave ablation treatment dosage for liver tumors according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of an ex vivo pig liver microwave ablation simulation of a control method for microwave ablation treatment dosage for liver tumors according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of ex vivo pig liver ablation for controlling microwave ablation treatment dosage for liver tumors according to an embodiment of the present invention;

FIG. 6 is a graph of the ablation effect of an ex vivo pig liver 50W-50min ablation dose according to the control method of the microwave ablation treatment dose for liver tumor of the embodiment of the invention;

FIG. 7 shows simulated temperature and actual temperature changes at a certain point during 50w-5min ablation dosage of an ex-vivo pig liver according to the control method of microwave ablation treatment dosage for liver tumor of the present invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

As shown in fig. 1, a flowchart of a method for controlling the microwave ablation therapeutic dose for liver tumor, which can feedback-regulate the therapeutic dose of microwave ablation according to the temperature data obtained by a temperature measuring needle during tumor ablation and the temperature data of the same site in a simulated temperature field, includes the following steps:

s1, constructing a liver microwave ablation simulation model according to the size of an actual liver tumor, wherein the liver microwave ablation simulation model is realized through a multi-physical-field simulation software COMSOL Multiphysics, and a two-dimensional axisymmetric assembly is adopted to design the geometric structures of an ablation needle and the liver, set material parameters, and form an electromagnetic radiation model and a biological heat conduction model;

s2, setting ablation dosage, namely ablation power and ablation time, a temperature measuring needle and an ablation needle side-by-side distance and the insertion depth of the ablation needle and the temperature measuring needle according to the actual tumor size;

s3, completing simulated ablation according to the set ablation dosage, and simultaneously obtaining real-time temperature change data of the temperature measurement sites of the corresponding side-by-side distances;

s4, inserting the ablation needle and the temperature measuring needle into the tumor tissue side by side according to a preset distance, ensuring that the ablation needle and the temperature measuring needle are positioned on the same plane, simultaneously connecting the ablation needle and the temperature measuring needle with a microwave ablation treatment system and a temperature measuring system, and starting actual ablation;

s5, starting actual ablation according to a preset ablation dosage, comparing the average value of the temperature measuring point on the temperature measuring needle with the average value of the temperature of the same point in simulation in real time every 15 seconds, feeding back and regulating the ablation dosage according to the result, keeping the ablation dosage unchanged if the result of subtracting the simulation temperature average value from the actual temperature average value is more than or equal to 0 and less than or equal to 15 ℃, and continuing to ablate until the end; if the difference between the actual temperature average value and the simulated temperature average value is larger than 15 ℃, reducing the ablation dosage to a preset ablation dosage, and continuing ablation; and if the simulation temperature average value minus the actual temperature average value is more than 15 ℃, increasing the ablation dosage to a preset ablation dosage, and continuing ablation.

As shown in fig. 2, a working schematic diagram of a microwave ablation therapeutic dose control method for liver tumor application to microwave thermal ablation of tumor is shown, wherein 1 is a microwave ablation and temperature measurement system (KY-2000 ablation therapeutic apparatus is taken as an example), 2 is an ablation needle (KY-2450A ablation needle is taken as an example), 3 is a temperature measurement needle (KY-CWZ-180 is taken as an example), and 4 is a liver tumor. When the method is used for tumor microwave thermal ablation temperature measurement, temperature measurement point simulation temperature data obtained by preoperative simulation is led into a microwave ablation and temperature measurement system in advance, an algorithm is set, the simulation temperature data and temperature data obtained by a temperature measurement needle in real time are averaged every 15 seconds and compared, and then the ablation dosage is fed back and adjusted.

Fig. 3 shows an ablation needle and a liver simulation geometric model for a method for controlling the microwave ablation treatment dosage of a liver tumor. The ablation needle is designed according to the size specification of an actual ablation needle (KY-2450A ablation needle is taken as an example), and the ablation model comprises the following components: the puncture head (front end 11mm), stainless steel sleeve (diameter 1.9mm), coaxial cable (divide into inner conductor, insulating medium and outer conductor), insulating medium cover (PTFE) four parts, merge puncture head and coaxial cable inner conductor into a domain, coaxial cable insulating medium and insulating medium cover merge into a domain, the liver is a domain, other sets are the ideal electric conductor boundary, construct two-dimentional axisymmetric model liver microwave ablation geometric figure.

Wherein the electromagnetic radiation domain comprises liver and PTFE material part, constant pressure heat capacity Cp, thermal conductivity к, density rho and relative dielectric constant are set according to thermophysical parameters of liver_rThe model of the change in conductivity σ, etc. with time is as follows:

κ＝0.512 293.15≤T≤473.15

in addition, the parameters of the material (PTFE polytetrafluoroethylene) of the ablation needle are set_PTFE＝2，σ_PTFE0, the boundary temperature T of the inner conductor and the outer conductor of the ablation needle and the stainless steel sleeve₀293.15 to simulate the water cooling effect of the ablation needle.

As shown in fig. 4, a schematic diagram of microwave ablation simulation under a dosage of 50W-5min for a control method of microwave ablation treatment dosage for liver tumor; the temperature measuring needle and the ablation needle are arranged in parallel side by side, the distance from the temperature measuring needle to the ablation needle is set to be 1cm, the end point of the temperature measuring needle is flush with the energy radiation end of the ablation needle, the middle needle in the drawing is the ablation needle, and the side white line is the position indication of the temperature measuring needle; the top end of the ablation needle is provided with a microwave transmission port which is a coaxial port, and the microwave frequency is set to be 2450 MHz; the microwave power is selected to be 50W, the ablation time is 5min, and then ablation simulation can be started. And performing visual processing on the simulation data to obtain temperature field distribution data, and further obtaining temperature change data of the same point of the temperature measuring point.

As shown in fig. 5, a schematic diagram of in vitro pig liver ablation of a control method of microwave ablation therapeutic dose for liver tumor, 1 is a microwave ablation and temperature measurement system (KY-2000 ablation therapeutic apparatus is taken as an example), 2 is an ablation needle (KY-2450A ablation needle is taken as an example), 3 is a temperature measurement needle (KY-CWZ-180 is taken as an example), and 5 is an in vitro pig liver; the temperature measuring needle and the ablation needle are arranged in parallel side by side and 1cm away from the ablation needle, and the front end of the temperature measuring needle is flush with the energy radiation end of the ablation needle.

As shown in fig. 6, a graph of ablation effect of an ex vivo pig liver with an ablation dose of 50W-50min according to a control method of microwave ablation treatment dose for liver tumor; the white lines in the figure are the puncture paths of the ablation needle and the temperature measuring needle.

Fig. 7 shows the simulated temperature and the actual temperature change at a certain point in the 50w-5min ablation dosage process of an in vitro pig liver of a control method of microwave ablation therapeutic dosage for liver tumor; because the temperature measuring point of the KY-CWZ-180 temperature measuring needle is positioned at the tip of the needle, the position of the temperature measuring point can be determined, and the temperature change data of the corresponding point (the black point at the front end of the white line in the figure 4) is found out in the simulation temperature field; if the result of subtracting the simulation temperature average value from the actual temperature average value is more than or equal to 0 and less than or equal to 15 ℃, keeping the ablation dosage unchanged, and continuing ablation until the end; if the difference between the actual temperature average value and the simulated temperature average value is larger than 15 ℃, reducing the ablation dosage to a preset ablation dosage, and continuing ablation; and if the simulation temperature average value minus the actual temperature average value is more than 15 ℃, increasing the ablation dosage to a preset ablation dosage, and continuing ablation. In fig. 7, at a dose of 50W-5min, the result of subtracting the simulated temperature average value from the actual temperature average value in the whole process is more than or equal to 0 and less than or equal to 15 ℃, which indicates that the ablation dose is proper. The 15 ℃ threshold value is obtained by comparing a large amount of in-vitro pig liver ablation experiments with simulation data.

The foregoing is only a preferred embodiment of the present invention; the scope of the invention is not limited thereto. Any person skilled in the art should be able to cover the technical scope of the present invention by equivalent or modified solutions and modifications within the technical scope of the present invention.