Electrode needle parameter determination method and determination system
By constructing and optimizing the ablation field suitability objective function, determining the needle position, status and characteristic parameters of the electrode needle, the problem of unsatisfactory preoperative planning in the existing technology is solved, and a better ablation range and reduced doctor experience is achieved. The effect of dependency.
Patent Information
- Application Number
- CN202310974765.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-03
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, the parameters of the electrode needle cannot be effectively planned before surgery, resulting in an unsatisfactory ablation range and relies on the experience of a doctor to distribute the needle.
By obtaining the historical image of the target target area, determining the needle channel position, state and characteristic parameters of multiple electrode needles, constructing the ablation field suitability objective function, and optimizing the objective function to obtain the maximum value parameters.
It realizes the ideal of assisting doctors in planning electrode needle parameters before surgery, improves the ablation range, and reduces dependence on doctor experience.
Smart Images
Figure CN119454226A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of medical devices, and in particular to a method and system for determining electrode needle parameters. Background Art
[0002] Compound pulsed electric field is an irreversible electroporation technology, also known as nanoknife. Its working principle is that when the electric field strength increases to the millivolt level, the nanoscale micropores in the cell membrane will not automatically close and disappear after the electric field is removed, and the cell membrane will be irreversibly damaged, and the cells will die without the use of chemotherapy drugs. Nanoknife is a non-temperature-dependent local tumor ablation technology that does not cause protein denaturation and will not cause thermal damage to heat-sensitive tissues such as adjacent blood vessels, bile ducts, diaphragm, gastrointestinal tract, etc., and can achieve ablation treatment of special parts that cannot be treated by thermal ablation. Nanoknife was approved for clinical treatment by the China Food and Drug Administration in June 2015.
[0003] At present, there are clinical trials to carry out research related to nanoknife, mainly focusing on clinical treatment and experimental research on diseases such as liver cancer, pancreatic cancer, kidney tumors, bone tumors, and intestinal tumors. The current common ablation methods include ultrasound-guided ablation during surgical laparotomy or percutaneous CT-guided ablation. The former is more harmful to patients, while the latter relies more on the doctor's experience in needle placement and planning, and there is no standardized preoperative surgical planning process. Therefore, there is an urgent need for a method that can assist doctors in planning the needle path and related parameters of the electrode needle before surgery, so as to obtain the ideal ablation range better and faster. Summary of the invention
[0004] The purpose of the embodiment of the present invention is to provide a method and system for determining electrode needle parameters, which determines the needle track positions, states and characteristic parameters of the multiple electrode needles based on the historical images of the target target area, and determines the ablation field conformality objective function based on the needle track positions, states and characteristic parameters of the multiple electrode needles, so that the ablation field generated by the target target area meets the target number of electrode needles when the ablation field conformality value is the maximum. The needle track positions, states and characteristic parameters of the target number of electrode needles are the parameters of the electrode needles, thereby determining the parameters of the relevant electrode needles. The present invention solves the technical problem in the prior art that preoperative planning can only rely on the doctor's experience and cannot obtain an ideal ablation range.
[0005] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a method and system for determining electrode needle parameters, the determination method comprising: determining the needle track positions, states and characteristic parameters of the multiple electrode needles according to the historical images of the target area; constructing an ablation field conformality objective function for different numbers of electrode needles according to the needle track positions, states, characteristic parameters of the multiple electrode needles, the coverage rate and over-ablation rate of the target area, wherein the electrode needles are composed of any two electrode needles among the multiple electrode needles; and obtaining the needle track positions, states and characteristic parameters of the target number of electrode needles when the value of the ablation field conformality objective function is maximum; and determining the needle track positions, states and characteristic parameters of the target number of electrode needles as the needle track positions, states and characteristic parameters of the target number of electrode needles.
[0006] Optionally, the determination method also includes determining the directions of the needle paths of the multiple electrode needles based on historical images of the target target area: constructing a three-dimensional model including the target target area, the skin around the target target area, and the endangered organs around the target target area based on the historical images of the target target area; collecting multiple three-dimensional coordinate points based on the three-dimensional model of the skin around the target target area; determining the geometric center of the target target area based on the three-dimensional model of the target target area; and determining the three-dimensional coordinate point that is located in the same cross-section as the geometric center of the target target area and is closest to the geometric center of the target target area as an electrode needle entry point, wherein the one electrode needle is an electrode needle among the multiple electrode needles; and determining the direction of a line connecting the needle entry point of the one electrode needle and the geometric center of the target target area as the direction of the needle path of the multiple electrode needles.
[0007] Optionally, based on historical images of the target area, determining the needle track positions of the multiple electrode needles includes: constructing a three-dimensional cube model including the target area based on the three-dimensional model of the target area; sampling at a specific interval on the three-dimensional cube model to obtain the residence points of the multiple electrode needles; and determining the positions of the multiple electrode needles along the directions of the needle tracks of the multiple electrode needles and passing through the residence points of the multiple electrode needles as the needle track positions of the multiple electrode needles.
[0008] Optionally, constructing an ablation field conformality objective function for different numbers of electrode needles based on the needle track positions of the multiple electrode needles, the states of the multiple electrode needles and the characteristic parameters of the multiple electrode needles includes: constructing an ablation field model based on the needle track positions, states and characteristic parameters of the multiple electrode needles; and constructing an ablation field conformality objective function for different numbers of electrode needles based on the ablation field model, the coverage rate and over-ablation rate of the target area.
[0009] Optionally, the constructing of the ablation field conformity objective function for different numbers of electrode needles includes constructing the ablation field conformity objective function Q for s electrode needles expressed by the following formula, Q=λ 1 Q 1 -λ 2 Q 2 , Where F represents the ablation field model, Q 1 (F) represents the coverage of the target area, Q 2 (F) represents the overablation rate, V H (F) represents the total volume of the ablation field targeted by s electrodes, V T Represents the volume of the target area, V O represents the volume of the organ at risk contained in the ablation field targeted by s electrodes during ablation, λ 1 represents the weight of the coverage of the target area, λ 2 Represents the weight of the ablation rate.
[0010] Optionally, before executing the step of obtaining the needle track position, state and characteristic parameters of the target number of electrodes when the value of the ablation field conformality objective function is maximum, the determination method also includes: optimizing the ablation field conformality objective function by simulated annealing; and the optimization end condition is to end when the value of the ablation field conformality objective function is maximum when the preset iteration rounds and / or the annealing temperature reaches the set temperature.
[0011] Optionally, determining the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles according to historical images of the target area includes: determining the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles according to the volume of the target area.
[0012] On the other hand, the present invention also includes a system for determining electrode needle parameters, which includes: a first determination device for determining the needle track position, state and characteristic parameters of the multiple electrode needles based on the historical images of the target target area; a construction device for constructing an ablation field conformality objective function for different numbers of electrode needles based on the needle track position, state, characteristic parameters of the multiple electrode needles, the coverage rate and over-ablation rate of the target target area, wherein the electrode needles are composed of any two electrode needles from the multiple electrode needles; and an acquisition device for acquiring the needle track position, state and characteristic parameters of the target number of electrode needles when the value of the ablation field conformality objective function is maximum; and a second determination device for determining the needle track position, state and characteristic parameters of the target number of electrode needles as the needle track position, state and characteristic parameters of the target number of electrode needles.
[0013] Optionally, the first determination device is also used to determine the directions of the needle paths of the multiple electrode needles based on historical images of the target target area: construct a three-dimensional model including the target target area, the skin around the target target area, and the endangered organs around the target target area based on the historical images of the target target area; collect multiple three-dimensional coordinate points based on the three-dimensional model of the skin around the target target area; determine the geometric center of the target target area based on the three-dimensional model of the target target area; and determine the three-dimensional coordinate point that is located in the same cross-section as the geometric center of the target target area and is closest to the geometric center of the target target area as the needle entry point of an electrode needle, wherein the one electrode needle is one of the multiple electrode needles; and determine the direction of the line connecting the needle entry point of the one electrode needle and the geometric center of the target target area as the direction of the needle path of the multiple electrode needles.
[0014] Optionally, the determination device determines the needle track positions of the multiple electrode needles based on historical images of the target area, including: constructing a three-dimensional cube model including the target area based on the three-dimensional model of the target area; sampling at a specific interval on the three-dimensional cube model to obtain the residence points of the multiple electrode needles; and determining the positions of the multiple electrode needles along the directions of the needle tracks of the multiple electrode needles and passing through the residence points of the multiple electrode needles as the needle track positions of the multiple electrode needles.
[0015] Through the above technical scheme, by acquiring historical images of the target target area, the needle track positions, states and characteristic parameters of the multiple electrode needles are determined; according to the needle track positions, states, characteristic parameters of the multiple electrode needles, the coverage rate and over-ablation rate of the target target area, an ablation field conformality objective function for different numbers of electrode needles is constructed; and the needle track positions, states and characteristic parameters of the target number of electrode needles when the value of the ablation field conformality objective function is maximized are obtained; and the needle track positions, states and characteristic parameters of the target number of electrode needles are determined as the needle track positions, states and characteristic parameters of the target number of electrode needles. This technical scheme constructs an ablation field conformality objective function according to the needle track positions, states, characteristic parameters of the electrode needles and the coverage rate and over-ablation rate of the target target area, and determines the needle track positions, states and characteristic parameters of the target number of electrode needles when the value of the ablation field conformality objective function is maximized, thereby assisting doctors in planning relevant parameters of electrode needles before surgery, without relying on the doctor's experience to determine the above-mentioned relevant parameters of the electrode, and an ideal ablation range can be obtained. The embodiments of the present invention solve the technical problem in the prior art that preoperative planning can only rely on the doctor's experience and that an ideal ablation range cannot be obtained.
[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:
[0018] Figure 1 is a flow chart of a method for determining electrode needle parameters provided by an embodiment of the present invention;
[0019] Figure 2 is a flow chart of determining the direction of an electrode needle track provided by an embodiment of the present invention;
[0020] Figure 3 A three-dimensional model diagram including a target area and surrounding skin provided by an embodiment of the present invention;
[0021] Figure 4 It is a schematic diagram of a cross section including a target area provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0022] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.
[0023] Before describing the embodiments of the present invention, further explanations are given for the technical terms involved in the specification.
[0024] Target volume: TV (Target volume) refers to the tumor to be ablated.
[0025] Organs at risk: OAR (Organ at risk) areas, including blood vessels, bones, and important organs (such as heart, lungs, pancreas, liver, kidneys, and brain);
[0026] Ablation field: The electrode needles are combined in pairs, with the distance between the needle tips of the two ablation needles as the major axis of the ellipse and the length of the exposed electrodes of the electrode needles as the thickness to form an elliptical cylinder, which is the ablation field formed by a pair of electrode needles; when there are multiple pairs of electrode needles, the ablation field is the sum of the volumes of the elliptical cylinders formed by the electrode needles combined in pairs.
[0027] refer to Figure 1 The flowchart of the method for determining the electrode needle parameters provided by the embodiment of the present invention is as follows: wherein the method for determining the electrode needle parameters includes the following steps S100-S103.
[0028] S100, determining the needle track positions, states and characteristic parameters of the plurality of electrode needles according to historical images of the target area.
[0029] Specifically, the historical image may refer to a CT image or MRI (magnetic resonance imaging) image of the patient, and the position of the target area of the patient can be obtained based on the historical image of the patient, and the target area can be further ablated. In the embodiment of the present invention, MRI images are preferred, and MRI images can obtain images of cross-sections, sagittal planes, and coronal planes with good spatial resolution. The method for determining the needle track position, state, and characteristic parameters of the multiple electrode needles can refer to the following steps.
[0030] Further, refer to Figure 2 The method for determining the electrode needle parameters also includes determining the directions of the electrode needle paths according to the historical images of the target area. The method for determining the electrode needle parameters includes determining the directions of the electrode needle paths of the multiple electrode needles according to the historical images of the target area. The method for determining the directions of the electrode needle paths of the multiple electrode needles includes the following steps S200-S203.
[0031] S200: constructing a three-dimensional model including the target area, skin around the target area, and organs at risk around the target area according to historical images of the target area.
[0032] Specifically, after obtaining historical images of the target area, the target area, the skin around the target area, and the organs at risk around the target area are outlined, and a three-dimensional model is established based on the target area, the skin around the target area, and the organs at risk around the target area. It is only necessary to determine the above three important tissues.
[0033] The above-mentioned target area, the skin around the target area, and the organs at risk around the target area are obtained and their three-dimensional models are constructed. The main purpose is to determine the needle insertion point and direction in the future and to avoid the needle path of the electrode needle during needle insertion to achieve better subsequent ablation effects.
[0034] S201. Collect a plurality of three-dimensional coordinate points based on a three-dimensional model of the skin around the target area.
[0035] S202: Determine the geometric center of the target area according to the three-dimensional model of the target area.
[0036] Specifically, refer to Figure 3 The three-dimensional model of the target area and the skin around the target area provided by the embodiment of the present invention is a three-dimensional model. A plurality of three-dimensional coordinate points are collected on the three-dimensional model around the target area. For example, Figure 3 As shown, three three-dimensional coordinate points M, N, and P are collected on the skin near the target area. The purpose of collecting the three-dimensional coordinate points is to further determine the direction of the needle track of the electrode needle. After determining the direction of one needle track, the remaining multiple needle tracks are parallel to the needle track. This is because the needle tracks cannot cross each other to avoid short circuits between the electrode needles.
[0037] The geometric center of the target area is determined based on the three-dimensional model of the target area. The shape of the target area is usually irregular, and the target area is regarded as a geometric shape with uniform density. Determining the centroid of the geometric shape is to determine the geometric center of the target area.
[0038] S203, determine the three-dimensional coordinate point that is located in the same cross-section as the geometric center of the target area and is closest to the geometric center of the target area as the needle entry point of one of the multiple electrode needles, and determine the direction of the line connecting the needle entry point of the one electrode needle and the geometric center of the target area as the direction of the needle track of the multiple electrode needles.
[0039] Specifically, from Figure 3 Among the three three-dimensional coordinate points M, N, and P in the figure, the three-dimensional coordinate point N located in the same cross section as the geometric center O is selected as the pending needle entry point of one electrode needle among the multiple electrode needles. The reason for determining the N point as the pending needle entry point is that only one of the above two conditions is currently met, so it is called the pending needle entry point.
[0040] Further, refer to Figure 4 is a schematic diagram of a cross section of a target area provided by an embodiment of the present invention. To determine the insertion point of an electrode needle, it is also necessary to simultaneously satisfy that the three-dimensional coordinate point is closest to the geometric center O of the target area. For example, refer to Figure 4 A plurality of three-dimensional coordinate points A, B, C, and N on the skin near the target area on the cross section are selected, and the point closest to the geometric center O of the target area is used as the insertion point of one of the plurality of electrode needles. Figure 4 It can be seen from the figure that the three-dimensional coordinate point closest to the geometric center O of the target area is point N, that is, the three-dimensional coordinate point N satisfies the above two conditions at the same time, thereby determining the three-dimensional coordinate point N as the insertion point of one of the multiple electrode needles.
[0041] After one of the needle insertion points N is determined, the direction of the line connecting the needle insertion point N and the geometric center O of the target area is determined as the needle insertion direction of one electrode needle among the multiple electrode needles, and the needle insertion directions of the other multiple electrode needles are parallel to the needle insertion direction of the one electrode needle, that is, the needle insertion directions of the multiple electrode needles, and the needle insertion directions of the multiple electrode needles are determined as the directions of the needle tracks of the multiple electrode needles ( Figure 4 The dotted line direction in the figure can be regarded as the direction of the needle tracks of the multiple electrode needles).
[0042] The above technical solution takes into account that the patient is usually in a supine position during surgery, and it is more convenient to operate the electrode needle by selecting the to-be-determined needle insertion direction parallel to the cross section. In addition, the three-dimensional coordinate point closest to the geometric center of the target area is determined as the needle insertion point of one of the multiple electrode needles. The closer the needle insertion point is to the target area, the better the ablation effect, and the smaller the impact on other normal tissues or cells around it. Among them, the needle insertion direction parallel to a determined electrode needle is determined as the needle insertion direction of multiple electrode needles, which avoids crossing between electrode needles, reduces the risk of short circuit, and makes the ablation process safer.
[0043] Furthermore, based on historical images of the target area, determining the needle track positions of the multiple electrode needles includes: constructing a three-dimensional cube model including the target area based on the three-dimensional model of the target area; sampling at a specific interval on the three-dimensional cube model to obtain the residence points of the multiple electrode needles; and determining the positions of the multiple electrode needles along the directions of the needle tracks of the multiple electrode needles and passing through the residence points of the multiple electrode needles as the needle track positions of the multiple electrode needles.
[0044] Specifically, according to the three-dimensional model of the target area, a three-dimensional cube model including the target area is constructed. After the insertion directions of the plurality of electrode needles are determined in the above steps (refer to Figure 3 The direction from point N to point O in the cross section is considered as the x-axis of the three-dimensional coordinate axis, the direction perpendicular to the electrode needle insertion direction on the cross section is considered as the y-axis of the three-dimensional coordinate axis, and the direction perpendicular to the cross section is considered as the z-axis of the three-dimensional coordinate axis. A three-dimensional cube model including the target area is constructed along the insertion directions of the multiple electrode needles, that is, the volume of the constructed three-dimensional cube model is greater than or equal to the volume of the target area.
[0045] Sampling is performed at a specific spacing on the three-dimensional cube model to obtain multiple resident points of the electrode needles, that is, after the three-dimensional cube model is constructed, multiple resident points are sampled at a specific spacing (for example, the specific spacing can be selected as 2mm, and the ablation effect is better). The resident point is the coordinate point of the position where the electrode needle passes along the needle withdrawal direction (the direction opposite to the needle insertion direction) during the ablation process.
[0046] In order to ensure the ablation effect, a layer-by-layer ablation method is generally adopted. Therefore, after each layer of ablation, the needle will pass through multiple coordinate points during the withdrawal process. The coordinate points passed by the electrode needle in the withdrawal direction are regarded as residence points. For example, for a target area with a depth of 5 cm, in order to ensure the ablation effect, the depth of each ablation is 2 cm, that is, the length of the electrode exposed by the electrode needle each time is 2 cm. Therefore, for a target area with a depth of 5 cm, 2 cm is ablated first, and then the needle is withdrawn 2 cm for the second layer of ablation, and the third layer can be ablated for the last time by 1 cm. Therefore, the point at which the electrode needle is withdrawn each time can be regarded as a residence point. The residence point along the withdrawal direction of the electrode needle can be regarded as the center of the exposed electrode on each needle track.
[0047] In the embodiment of the present invention, the positions of the plurality of electrode needles along the needle paths of the plurality of electrode needles and passing through the stationary points of the plurality of electrode needles are determined as the needle path positions of the plurality of electrode needles. When the lengths of the electrode needles are known, the needle path positions of the plurality of electrode needles can be expressed as {X Needle =(P Handle ,P Target )}. Among them, P Handle represents the position of the electrode needle handle (which can be represented by a three-dimensional coordinate point), P Target Indicates the position of the tip of the electrode needle.
[0048] Further, determining the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles according to the historical images of the target area includes: determining the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles according to the volume of the target area.
[0049] The needle entry points of the n×n electrode needles are collected at a specific interval on the two-dimensional coordinate system (y, z) of the three-dimensional coordinate system, and regarded as a matrix of size n×n. At the same time, define A ij The i-th needle channel and the j-th needle channel in the matrix are states, A ij is one of the variables to be optimized. ij =1 means that the i-th needle track and the j-th needle track are activated, that is, discharge, and the i-th needle track and the j-th needle track form an ablation field; A ij =0 means that the i-th needle channel and the j-th needle channel are not activated, that is, no discharge occurs.
[0050] Therefore, the larger the volume of the target area, the more electrode needles are inserted, and the more electrode needles are in an activated state. Therefore, the states of multiple electrode needles and the characteristic parameters of multiple electrode needles are determined according to the volume of the target area. Among them, the characteristic parameters of the electrode needles may include the electrode bare leakage length, pulse voltage, pulse frequency, pulse width, number of pulse groups, number of pulses in each group, etc. After selecting the appropriate characteristic parameters, no modification is made for the same target area.
[0051] S101 . Constructing an ablation field conformality objective function for different numbers of electrode needles according to the needle track positions, states, characteristic parameters, target area coverage and over-ablation rate of the plurality of electrode needles.
[0052] Wherein, the electrode needles are composed of any two electrode needles among a plurality of electrode needles.
[0053] Specifically, the needle track position of the electrode needle can be understood as the position of the electrode needle in the needle track when the electrode needle is inserted into the target area along the direction of the needle track. Since the ablation process is layer-by-layer ablation in the form of needle withdrawal, the position of the electrode needle will change when the needle is withdrawn after ablation of a layer. The changed position of the electrode needle is determined as the new needle track position of the electrode needle. Therefore, the needle track position of the electrode needle is also one of the variables to be optimized.
[0054] Furthermore, constructing an ablation field conformality objective function for different numbers of electrode needles includes: constructing an ablation field model based on the needle track position, state and characteristic parameters of the multiple electrode needles; and constructing an ablation field conformality objective function for different numbers of electrode needles based on the ablation field model, coverage of the target area and over-ablation rate.
[0055] Specifically, first, according to the needle track positions {X Needle}、State A ij And characteristic parameters E, construct the ablation field model F. The ablation field model can be used It means that the ablation field model and the needle track position {X Needle}, how many electrode needles are there for electrode needle A ij The state is related to the characteristic parameter E. Function is the calculation formula of the ablation field, and the specific calculation method can be adopted, which will not be described in detail here.
[0056] Furthermore, the said constructing the ablation field conformity objective function for different numbers of electrode needles comprises: constructing the ablation field conformity objective function Q for s electrode needles expressed by the following formula, Q=λ 1 Q 1 -λ 2 Q 2 , Where F represents the ablation field model, Q 1 (F) represents the coverage of the target area, Q 2 (F) represents the overablation rate, V H (F) represents the total volume of the ablation field targeted by s electrodes, V T Represents the volume of the target area, V O represents the volume of the organ at risk contained in the ablation field targeted by s electrodes during ablation, λ1 represents the weight of the coverage of the target area, λ 2 Represents the weight of the ablation rate.
[0057] Specifically, the conformality of the ablation field is understood as the degree to which the distribution of the ablation field in three-dimensional space is consistent with the shape and size of the target target area. Exemplarily, assuming that the volume of the target target area is a regular cuboid, and the volume size is a tumor with a length, width and depth of 2×2×3cm for ablation, a three-dimensional cube model with a length, width and depth of 3×3×3cm is constructed to ensure that the volume of the three-dimensional cube model is greater than or equal to the volume of the target target area. Assuming that multiple residence points are collected at a specific spacing of 2mm on the three-dimensional cube model, 15×15×15 residence points and a matrix of 15×15 needle channels of electrode needles can be obtained. As for which needle channels in the matrix are finally selected to place electrode needles as effective needle channels (i.e., needle channels in the activated state) for the ablation field of the target target area, it is determined by the following steps.
[0058] V H (F) represents the total volume of the ablation field of s electrode needles, that is, the total volume of the ablation field of any number of s electrode needles among different numbers of electrode needles. For example, for the target area with a volume of 2×2×3cm, a needle track with a matrix of 15×15 electrode needles can be obtained. When the electrode needles in all needle tracks are activated, an ablation field is formed between any two electrode needles. The total volume of the final ablation field is the total volume of the ablation fields formed between the various needles after superposition. Among them, Q 1 (F), Q 2 (F) and V H (F) can be determined by existing technical means and will not be described in detail here.
[0059] According to the ablation field conformality objective function Q = λ 1 Q 1 -λ 2 Q 2 It can be seen that λ 1 Q 1 The larger the value, the higher the ablation coverage of the target area, and the more complete the ablation of the target area. Correspondingly, the higher the coverage of the ablation field, the greater the probability of over-ablation, that is, the greater the probability of over-ablation of normal cells around the target area. Conversely, 1 Q 1 The smaller the value, the lower the ablation coverage of the target area, which will lead to under-ablation and poor ablation effect of the target area. 2 Q 2 The smaller the value, the smaller the overablation rate of the ablation field, and the better the ablation effect. 1 Q 1 The larger the λ 1 Q1 The smaller it is, the better the ablation effect is. Therefore, when the value of the ablation field conformality objective function Q is the largest, the ablation effect is the best. Accordingly, when the value of the ablation field conformality objective function Q is the largest, the needle track position, state and characteristic parameters of the target electrode needle can be used as the parameters for needle placement.
[0060] There are also constraints on the spacing between the electrode needles. During the discharge process, all electrode needles must not pass through the endangered organs, and the distance between the needle tracks of any pair of electrode needles is between 1.5-4 cm. On the one hand, the generated ablation field is controllable; on the other hand, the ablation effect of the ablation field between the electrode needles is guaranteed.
[0061] Furthermore, before executing the step of obtaining the needle track position, state and characteristic parameters of the target number of electrodes when the value of the ablation field conformality objective function is maximum, the determination method also includes: optimizing the ablation field conformality objective function by a simulated annealing method, wherein the optimization end condition is a preset number of iterations and / or the annealing temperature is adjusted to a set temperature.
[0062] Specifically, before executing the step of obtaining the needle track positions, states and characteristic parameters of the target number of electrodes when the value of the ablation field conformality objective function is maximized, it is necessary to further optimize the ablation field conformality objective function Q so that the ablation field conformality objective function Q tends to be maximized. The parameters in the objective function Q can be optimized based on existing technical means such as simulated annealing to make the objective function tend to the maximum value.
[0063] Exemplarily, for the target area with a volume of 2×2×3cm, 15×15×15 dwell points and a matrix of 15×15 electrode needles can be determined. In order to maximize the value of the objective function Q, it is not necessarily necessary for all electrode needles in the needle track to be activated, nor is it necessarily necessary for the electrode needle to start ablation from the deepest part of the target area to maximize the objective function Q. Therefore, different weight coefficients can be set as needed. For example, in order to make the ablation conformal better while avoiding severe over-ablation, the weight of the coverage rate can be set to 0.8 and the weight of the over-ablation rate can be set to 0.2. For the needle track with a matrix of 15×15 electrode needles, set the initial state A of the electrode needles ij_0 , initial temperature T, lower limit temperature T min , cooling rate α and number of iterations N, determine the ablation field conformality objective function Q(A ij_0 ) is the initial value of the electrode. The state of the electrode targeting includes the needle track position {X Needle}、Electrode targeting state A ij .
[0064] Assume that in the initial state, 10 pairs of electrode needles are selected from different positions of the electrode needle tracks in the matrix 15×15, and the states of the electrode pairs are all activated, and the states of the electrode needles in the remaining electrode needle tracks are inactive. Randomly perturb the current state, change the needle track positions, states and characteristic parameters of different numbers of electrode needles, and a new state A will be obtained. ij_n , determine the new state A ij_n The objective function of ablation field conformality Q(A ij_n ) value;
[0065] Compare the state to the new state A ij_n The objective function of ablation field conformality Q(A ij_n ) and the previous state A ij_n-1 The objective function of ablation field conformality Q(A ij_n-1 ), where if Q(A ij_n ) <Q(A ij_n-1 ), then adjust the needle track position, state and characteristic parameters of the electrode to A ij_n state; if Q(A ij_n )≥Q(A ij_n-1 ), then with probability Adjust the needle track position, state and characteristic parameters of the electrode.
[0066] Determine the annealing temperature T n+1 =T n -α, α is the coefficient for controlling the rate of annealing temperature drop. If the annealing temperature T n+1 The lower limit of temperature T is not reached min , then continue to add new perturbations and repeat the above steps; if the annealing temperature T n+1 Reach the lower limit temperature T min , determine whether there are uninactivated targets; if so, start a new round of iteration; if not, output the needle track position, state and characteristic parameters of the optimized target number of electrodes. The specific method of optimizing the objective function Q by using the simulated annealing method is the same as the prior art, and will not be repeated here.
[0067] The optimization end condition is a preset iteration round (which can be set as needed) and / or an annealing temperature to a set temperature (which can be set as needed). The simulated annealing algorithm can be used to quickly optimize the objective function Q to maximize its value. Accordingly, when the value of the optimized objective function Q is maximized, the needle track position, state, and characteristic parameters of the target number of electrodes can be obtained.
[0068] The traditional nanoknife treatment optimization method requires complex calculations and simulations, which takes a long time. However, the present invention uses a simulated annealing algorithm with a faster optimization speed, which can determine the relevant parameters of the electrode needle in a shorter time, greatly shortening the time for electrode needle parameter planning.
[0069] S102, obtaining needle track positions, states and characteristic parameters of a target number of electrodes when the value of the ablation field conformality objective function is maximum.
[0070] S103, determining the needle track positions, states, and characteristic parameters of the target number of electrodes as the needle track positions, states, and characteristic parameters of the target number of electrodes.
[0071] Specifically, the optimized objective function Q obtains the maximum value, and the needle track position, state and characteristic parameters of the target number of electrode needles can be calculated accordingly. For example, in the above steps, the initial electrode needles are 10 pairs, and after optimization, it is finally solved that only 6 pairs of electrode needles are needed. After determining that the corresponding target electrode needles are 6 pairs, the needle track of the electrode needles can also be determined accordingly, where the characteristic parameter E is the initial value and is quantitative during the optimization process.
[0072] The needle track position, state and characteristic parameters of the target number of electrodes are used as parameters for actual needle placement on the target area, so as to achieve needle placement on target areas of different shapes on different patients in a short time, and the ablation field generated by the target number of electrodes can maximize the value of the objective function Q.
[0073] The above technical solution of the present invention can determine the parameters of the electrode pair that maximize the objective function Q in a short time. During the operation, the parameters of the electrode pair can be accurately placed on the patient's tumor and the electrode needle can be inserted into a reasonable depth to achieve better ablation effect.
[0074] Through the above technical scheme, by acquiring historical images of the target area, the needle track positions, states and characteristic parameters of the multiple electrode needles are determined; according to the needle track positions, states, characteristic parameters of the multiple electrode needles, the coverage rate and over-ablation rate of the target area, an ablation field conformality objective function for different numbers of electrode needles is constructed; and the needle track positions, states and characteristic parameters of the target number of electrode needles when the value of the ablation field conformality objective function is maximum are obtained; and the needle track positions, states and characteristic parameters of the target number of electrode needles are determined as the needle track positions, states and characteristic parameters of the target number of electrode needles. This technical solution constructs an ablation field conformality objective function based on the needle track position, state, characteristic parameters of the electrode needles, and the coverage rate and over-ablation rate of the target target area, and determines the needle track position, state and characteristic parameters of the target number of electrode needles when the ablation field conformality objective function has the maximum value, thereby determining the number of pairs of electrode needles for the target target area, the needle track position and characteristic parameters of the electrode needles, thereby assisting doctors in planning relevant parameters of the electrode needles before surgery, so as to obtain the ideal ablation range better and faster. The embodiment of the invention solves the technical problem that the prior art can only rely on the doctor's experience for preoperative planning and cannot obtain the ideal ablation range.
[0075] On the other hand, an embodiment of the present invention also provides a system for determining electrode needle parameters, the system for determining electrode needle parameters comprising: a first determining device for determining the needle track positions, states and characteristic parameters of the multiple electrode needles based on historical images of the target target area; a constructing device for constructing an ablation field conformality objective function for different numbers of electrode needles based on the needle track positions, states, characteristic parameters of the multiple electrode needles, the coverage rate and over-ablation rate of the target target area, wherein the electrode needles are composed of any two electrode needles from the multiple electrode needles; and an acquiring device for acquiring the needle track positions, states and characteristic parameters of the target number of electrode needles when the value of the ablation field conformality objective function is maximum; and a second determining device for determining the needle track positions, states and characteristic parameters of the target number of electrode needles as the needle track positions, states and characteristic parameters of the target number of electrode needles.
[0076] The details of the above-mentioned system for determining the electrode needle parameters and its effects can be found in the relevant description of the above-mentioned method for determining the electrode needle parameters, which will not be repeated here.
[0077] Furthermore, the first determination device is also used to determine the directions of the needle paths of the multiple electrode needles based on the historical images of the target target area: construct a three-dimensional model including the target target area, the skin around the target target area, and the endangered organs around the target target area based on the historical images of the target target area; collect multiple three-dimensional coordinate points based on the three-dimensional model of the skin around the target target area; determine the geometric center of the target target area based on the three-dimensional model of the target target area; and determine the three-dimensional coordinate point that is located in the same cross-section as the geometric center of the target target area and is closest to the geometric center of the target target area as the needle entry point of an electrode needle, wherein the one electrode needle is one of the multiple electrode needles; and determine the direction of the line connecting the needle entry point of the one electrode needle and the geometric center of the target target area as the direction of the needle path of the multiple electrode needles.
[0078] The details of the above-mentioned system for determining the electrode needle parameters and its effects can be found in the relevant description of the above-mentioned method for determining the electrode needle parameters, which will not be repeated here.
[0079] Furthermore, the first determination device is used to determine the needle track positions of the multiple electrode needles based on the historical images of the target target area, including: constructing a three-dimensional cube model containing the target target area based on the three-dimensional model of the target target area; sampling at a specific interval on the three-dimensional cube model to obtain the residence points of the multiple electrode needles; and determining the positions of the multiple electrode needles along the directions of the needle tracks of the multiple electrode needles and passing through the residence points of the multiple electrode needles as the needle track positions of the multiple electrode needles.
[0080] The details of how the first determination device determines the needle track positions of the plurality of electrode needles and the effects thereof can be found in the related description of the electrode needle parameter determination method, which will not be elaborated herein.
[0081] Furthermore, the construction device is used to construct an ablation field conformality objective function for different numbers of electrode needles based on the needle track positions of the multiple electrode needles, the states of the multiple electrode needles and the characteristic parameters of the multiple electrode needles, including: constructing an ablation field model based on the needle track positions, states and characteristic parameters of the multiple electrode needles; and constructing an ablation field conformality objective function for different numbers of electrode needles based on the ablation field model, the coverage rate and over-ablation rate of the target area.
[0082] Furthermore, the construction device is used to construct the ablation field conformity objective function for different numbers of electrode needles, including: constructing the ablation field conformity objective function Q for s electrode needles represented by the following formula, Q=λ 1 Q 1 -λ 2 Q 2 , Where F represents the ablation field model, Q 1 (F) represents the coverage of the target area, Q 2 (F) represents the overablation rate, V H (F) represents the total volume of the ablation field targeted by s electrodes, V T Represents the volume of the target area, V O represents the volume of the organ at risk contained in the ablation field targeted by s electrodes during ablation, λ 1 represents the weight of the coverage of the target area, λ 2 Represents the weight of the ablation rate.
[0083] The details and effects of the above-mentioned construction device for constructing the ablation field conformality objective function for different numbers of electrode needles can be found in the relevant description of the above-mentioned method for determining the electrode needle parameters, which will not be elaborated here.
[0084] Furthermore, before the determination system executes the step of obtaining the needle track position, state and characteristic parameters of the target number of electrodes when the value of the ablation field conformality objective function is maximum, the determination method also includes: optimizing the ablation field conformality objective function by a simulated annealing method, wherein the optimization end condition is a preset number of iterations and / or the annealing temperature is adjusted to a set temperature.
[0085] Furthermore, the second determination device is used to determine the status of the multiple electrode needles and the characteristic parameters of the multiple electrode needles based on the historical images of the target area, including: determining the status of the multiple electrode needles and the characteristic parameters of the multiple electrode needles based on the volume of the target area.
[0086] The details and effects of the second determination device determining the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles can be found in the related description of the electrode needle parameter determination method, which will not be elaborated here.
[0087] The details of the above-mentioned system for determining the electrode needle parameters and its effects can be found in the relevant description of the above-mentioned method for determining the electrode needle parameters, which will not be repeated here.
[0088] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.
[0089] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
[0090] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.
[0091] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.
[0092] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.
[0093] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.
[0094] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.
[0095] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.
[0096] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.
Claims
1. A method for determining electrode needle parameters, characterized in that: The determination method comprises: Determining the needle track positions, states and characteristic parameters of the plurality of electrode needles according to the historical images of the target area; According to the needle track positions, states, characteristic parameters, target area coverage and over-ablation rate of the plurality of electrode needles, constructing an ablation field conformality objective function for different numbers of electrode needles, wherein the electrode needles are composed of any two electrode needles from the plurality of electrode needles; and Obtaining needle track positions, states and characteristic parameters of a target number of electrodes when the value of the ablation field conformality objective function is maximum; and The needle track positions, states and characteristic parameters of the target number of electrodes are determined as the needle track positions, states and characteristic parameters of the target number of electrodes.
2. The method according to claim 1, characterized in that: The determination method further includes determining directions of the needle tracks of the plurality of electrode needles according to historical images of the target area: constructing a three-dimensional model including the target area, skin around the target area, and organs at risk around the target area according to historical images of the target area; Collecting a plurality of three-dimensional coordinate points according to the three-dimensional model of the skin around the target area; Determining the geometric center of the target area according to the three-dimensional model of the target area; Determine the three-dimensional coordinate point located in the same cross section as the geometric center of the target area and closest to the geometric center of the target area as the insertion point of an electrode needle, wherein the electrode needle is one of the multiple electrode needles; and The direction of the line connecting the needle insertion point of the one electrode needle and the geometric center of the target area is determined as the direction of the needle tracks of the multiple electrode needles.
3. The method according to claim 2, characterized in that Determining the needle track positions of the plurality of electrode needles according to the historical images of the target area includes: According to the three-dimensional model of the target area, construct a three-dimensional cube model including the target area; Sampling at a specific interval on the three-dimensional cube model to obtain the residence points of multiple electrode needles; and Positions of the plurality of electrode needles along the directions of the needle tracks of the plurality of electrode needles and passing through the stationary points of the plurality of electrode needles are determined as needle track positions of the plurality of electrode needles.
4. The method according to claim 1, characterized in that According to the needle track positions of the plurality of electrode needles, the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles, constructing the ablation field conformality objective function for different numbers of electrode needles includes: constructing an ablation field model according to the needle track positions, states and characteristic parameters of the plurality of electrode needles; and According to the ablation field model, the coverage rate of the target area and the over-ablation rate, an ablation field conformality objective function for electrode needles with different numbers of electrode needles is constructed.
5. The method according to claim 4, characterized in that The construction of the ablation field conformality objective function for different numbers of electrodes comprises: Construct the ablation field conformality objective function Q for s electrodes as shown below: Q=λ1Q1-λ2Q2, Where F represents the ablation field model, Q1(F) represents the coverage of the target area, Q2(F) represents the overablation rate, and V H (F) represents the total volume of the ablation field targeted by s electrodes, V T Represents the volume of the target area, V O represents the volume of the organ at risk when the ablation field targeted by the s electrodes produces over-ablation, λ1 represents the weight of the coverage rate of the target area, and λ2 represents the weight of the over-ablation rate.
6. The method according to claim 5, characterized in that Before executing the step of obtaining the needle track positions, states and characteristic parameters of the target number of electrodes when the value of the ablation field conformality objective function is maximized, the determination method further includes: The conformality objective function of the ablation field is optimized by a simulated annealing method. The optimization end condition is to preset the iteration rounds and / or the annealing temperature to the set temperature.
7. The method according to claim 5, characterized in that Determining the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles according to the historical images of the target area includes: According to the volume of the target area, the states of the plurality of electrode needles and the characteristic parameters of the plurality of electrode needles are determined.
8. A system for determining electrode needle parameters, characterized in that: The electrode needle parameter determination system comprises: A first determining device, for determining the needle track positions, states and characteristic parameters of the plurality of electrode needles according to the historical images of the target area; A construction device for constructing an ablation field conformality objective function for different numbers of electrode needles according to the needle track positions, states, characteristic parameters, coverage of target areas and over-ablation rates of the plurality of electrode needles, wherein the electrode needle pair is composed of any two electrode needles from the plurality of electrode needles; and An acquisition device, used to acquire the needle track position, state and characteristic parameters of the target number of electrodes when the value of the ablation field conformality objective function is maximum; and The second determining device determines the needle track positions, states and characteristic parameters of the target number of electrodes as the needle track positions, states and characteristic parameters of the target number of electrodes.
9. The electrode needle parameter determination system according to claim 8, characterized in that: The first determining device is further used to determine the directions of the needle tracks of the plurality of electrode needles according to the historical images of the target area: constructing a three-dimensional model including the target area, skin around the target area, and organs at risk around the target area according to historical images of the target area; Collecting a plurality of three-dimensional coordinate points according to the three-dimensional model of the skin around the target area; Determining the geometric center of the target area according to the three-dimensional model of the target area; as well as Determine the three-dimensional coordinate point located in the same cross section as the geometric center of the target area and closest to the geometric center of the target area as the insertion point of an electrode needle, wherein the electrode needle is one of the multiple electrode needles; and The direction of the line connecting the needle insertion point of the one electrode needle and the geometric center of the target area is determined as the direction of the needle tracks of the multiple electrode needles.
10. The electrode needle parameter determination system according to claim 8, characterized in that: The first determining device, for determining the needle track positions of the plurality of electrode needles according to the historical images of the target area, comprises: According to the three-dimensional model of the target area, construct a three-dimensional cube model including the target area; Sampling at a specific interval on the three-dimensional cube model to obtain the residence points of multiple electrode needles; and Positions of the plurality of electrode needles along the directions of the needle tracks of the plurality of electrode needles and passing through the stationary points of the plurality of electrode needles are determined as needle track positions of the plurality of electrode needles.