CN115486935B

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Info

Publication number: CN115486935B
Application number: CN202211364798.9A
Authority: CN
Inventors: 张建浩
Original assignee: Tianjin Intelligent Health Co ltd
Current assignee: Tianjin Intelligent Health Co ltd
Priority date: 2022-11-02
Filing date: 2022-11-02
Publication date: 2023-06-13
Anticipated expiration: 2042-11-02
Also published as: CN115486935A

Abstract

The invention provides an ablation determining method and system, comprising the steps of modeling an operation target position before operation to obtain a three-dimensional model of the target position; extracting a first focus model and a blood vessel model from the three-dimensional model of the target position; randomly selecting a first coordinate point on the first focus model surface, and determining the maximum distance between the first coordinate point and the surface point; when the maximum distance is less than or equal to 2 x (maximum ablation distance-redundant distance), determining the first sphere as an ablation range; when the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), the second sphere is determined to be an ablation range. The technical problem of inaccurate determination of the ablation part is solved through the scheme.

Description

Ablation determination method and system

Technical Field

The invention relates to the field of medical data processing, in particular to an ablation determining method and an ablation determining system.

Background

Ablation refers to inactivation of tumor tissues by physical or chemical means, when a radiofrequency ablation technology is used for treating malignant tumors, ablation electrode needles with different shapes are usually inserted into malignant tumor tissues of a patient, alternating current generated by a radiofrequency generator is utilized to enable conductive ions and polarized molecules in the tissues to move at high speed along the direction of the radiofrequency current so as to generate Joule heat, heat energy is gradually and outwards conducted to tumor cells along with the increase of time, and the characteristic of poor bearing capacity of the tumor cells on high temperature is utilized to complete in-situ inactivation of the tumor cells.

Because three-dimensional images such as CT (computed tomography) and the like are poor in real-time performance and have radiation, the main flow of the current ablation operation is to scan a patient in two dimensions or three dimensions through medical imaging equipment before the operation, the malignant tumor in the patient is accurately positioned through the obtained scanned images, a doctor determines the specific position of the insertion of an ablation needle through personal experience, however, due to the limitation of the ablation temperature, the range of the ablation has a certain limitation, for a larger ablation target, such as a larger tumor with the number of 1 shown in FIG. 2, the range of one ablation needle cannot be completely covered, a plurality of ablation needles are required to be planned, but a plurality of ablation needles are particularly used, the position of each ablation needle is penetrated, the range of each ablation needle and the like are currently determined subjectively by the doctor, and the method is a great challenge for a new doctor; in addition, as shown in the tumor numbered 2 in fig. 2, which is relatively close to the blood vessel, it is necessary to further determine whether or not the ablation procedure can be performed in order to prevent the accidentally injuring the blood vessel.

Disclosure of Invention

In order to solve the above-mentioned problems in the background art, the present invention provides an ablation determining method and system.

In one aspect of the invention, there is provided an ablation determination method comprising the steps of: step S1, modeling a surgical target position before surgery to obtain a three-dimensional model of the target position; s2, extracting a first focus model and a blood vessel model from the three-dimensional model of the target position, wherein the first focus model and the blood vessel model are represented by the same coordinate system; step S3, randomly selecting a first coordinate point on the surface of the first focus model, preferentially searching the surface points of the nearby focus model according to the breadth from the first coordinate point, and determining the maximum distance between the first coordinate point and the surface points; step S4, when the maximum distance is smaller than or equal to 2 x (maximum ablation distance-redundant distance), adding redundant distances to two ends of the maximum distance line segment to obtain a first diameter, using the first diameter as a first sphere, performing collision detection on the first sphere and the blood vessel model, and stopping the flow if collision occurs, wherein the first focus cannot perform an ablation operation; otherwise, taking the sphere center of the first sphere as a target ablation point, taking the radius of the first sphere as a target ablation distance, and stopping the flow; step S5, when the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), searching a second coordinate point with the nearest distance of 2 x (maximum ablation distance-redundant distance) from the first coordinate point, connecting the first coordinate point with the second coordinate point, respectively adding redundant distances at two ends of the connecting line to obtain a second diameter, using the second diameter as a second sphere, performing collision detection on the second sphere and the vascular model, and stopping the flow if collision occurs, wherein the first focus cannot perform an ablation operation; otherwise, taking the sphere center of the second sphere as a target ablation point, and taking the radius of the second sphere as a target ablation distance; step S6, subtracting the second sphere from the first focus model, and returning to the step S3.

Further, the three-dimensional model is built by CT or MRI techniques.

Further, the lesion model only holds surface data of the lesion.

Further, the vessel model retains only vessels having diameters greater than a first threshold.

Further, the lesion model and the blood vessel model are expressed on the same coordinate system at the same scale.

The invention also discloses an ablation determining system, which is characterized by comprising the following modules: the model building module is used for modeling the surgical target position before the surgery to obtain a three-dimensional model of the target position; the model extraction module is used for extracting a first focus model and a blood vessel model from the three-dimensional model of the target position, wherein the first focus model and the blood vessel model are represented by the same coordinate system; a first calculation module, configured to randomly select a first coordinate point on the surface of the first lesion model, preferentially search surface points of a nearby lesion model with breadth from the first coordinate point, and determine a maximum distance between the first coordinate point and the surface points; the first determining module is used for respectively adding redundant distances to two ends of the maximum distance line segment to obtain a first diameter when the maximum distance is smaller than or equal to 2 x (maximum ablation distance-redundant distance), taking the first diameter as a first sphere, performing collision detection on the first sphere and the blood vessel model, and stopping the flow if collision occurs, the first focus can not perform ablation operation; otherwise, taking the sphere center of the first sphere as a target ablation point, taking the radius of the first sphere as a target ablation distance, and stopping the flow; the second determining module is used for searching a second coordinate point with the nearest distance of 2 x (maximum ablation distance-redundant distance) from the first coordinate point when the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), connecting the first coordinate point with the second coordinate point, respectively adding redundant distances at two ends of the connecting line to obtain a second diameter, using the second diameter as a second sphere, performing collision detection on the second sphere and the blood vessel model, and stopping the flow, wherein if collision occurs, the first focus can not perform an ablation operation; otherwise, taking the sphere center of the second sphere as a target ablation point, and taking the radius of the second sphere as a target ablation distance; and a third determining module for subtracting the second sphere from the first lesion model and returning to the first calculating module.

Further, the three-dimensional model is built by CT or MRI techniques.

Further, the lesion model only holds surface data of the lesion.

According to the technical scheme, whether ablation can be performed or not is accurately determined, the insertion position and the ablation range of the ablation needle are reduced, errors of human judgment are reduced, and the success rate of an ablation operation is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of the process of the present invention;

FIG. 2 is a schematic view of lesions of different sizes and locations;

FIG. 3 is a schematic view of the maximum distance;

FIG. 4 shows that the maximum ablation extent is greater than the lesion schematic;

FIG. 5 shows that the maximum ablation extent is less than the lesion schematic;

fig. 6 lesion model minus first ablation sphere map;

FIG. 7 is a schematic view of a second ablation balloon;

FIG. 8 lesion model minus two ablation sphere schematics;

FIG. 9 is a third ablation balloon illustration;

fig. 10 illustrates three ablation balls.

Detailed Description

The invention will be described with reference to the drawings and detailed description.

The present embodiment solves the above-described problems by:

in one embodiment, referring to fig. 1, the present invention provides an ablation determination method comprising the steps of:

step S1, modeling is carried out on the operation target position before operation, and a three-dimensional model of the target position is obtained.

Preoperative in the present invention refers to prior to performing an ablative procedure; the target position can be a position corresponding to one organ of a human body, such as thyroid, liver and the like, which are relatively more organs applied in the current ablation operation, and an ablation needle needs to be penetrated through the neck and the abdomen in the operation process, so the target position can be the position including the neck, the abdomen and the like of the target organ.

Any method in the prior art, such as CT scanning three-dimensional reconstruction, MRI three-dimensional reconstruction and the like, can be used for three-dimensional modeling of the surgical target position, and corresponding three-dimensional digital images are obtained through the existing three-dimensional modeling software for subsequent steps.

And S2, extracting a first focus model and a blood vessel model from the three-dimensional model of the target position, wherein the first focus model and the blood vessel model are represented by the same coordinate system.

After the three-dimensional model of the target position is obtained according to the existing scanning technology, the corresponding organs, lesions, blood vessels and other human tissues can be represented in the three-dimensional model. In order to facilitate the processing procedure, the invention needs to further express the focus in the three-dimensional model, the extraction of the focus model can be performed manually or automatically, and the invention is not limited; after the focus model is extracted, the coordinate point set or the form of a thread equation is expressed; further, the lesion model only holds surface data of lesions; further, as shown in fig. 2, there may be a plurality of lesions in the target location, and the embodiment of the present invention extracts only the first lesion model therein, and it is obvious that other lesions may be treated by using a similar scheme of the present invention.

Further, in order to detect whether the ablation operation can be performed on the target point, the present embodiment further extracts a blood vessel model, and the extraction of the blood vessel model may be performed manually or by any automatic extraction method in the prior art. Further, since only large blood vessels, such as the aorta, affect the ablation procedure, this embodiment extracts only blood vessels having a blood vessel diameter greater than the first threshold. The blood vessel model is also expressed in the form of a coordinate point set or a thread equation; further, in order to facilitate data processing, the first lesion model and the blood vessel model are represented by the same coordinate system, the lesion model and the blood vessel model are all expressed on the same coordinate system by the same scale, and the relationship between the models, such as distance, azimuth and the like, can be directly calculated by using the coordinates.

Step S3, randomly selecting a first coordinate point on the surface of the first focus model, preferentially searching the surface points of the nearby focus model according to the breadth from the first coordinate point, and determining the maximum distance between the first coordinate point and the surface points.

After the first focus model is determined, the three-dimensional coordinate of any point on the model surface can be obtained, one point is randomly selected on the model surface, the selected point is traversed from the periphery of the selected point, and the point with the largest distance with the selected point is searched; as shown in fig. 3, distances from other points of the model surface are calculated from the first coordinate point, and the point in which the distance is the largest is determined, and the maximum distance is calculated.

Step S4, when the maximum distance is smaller than or equal to 2 x (maximum ablation distance-redundant distance), adding redundant distances to two ends of the maximum distance line segment to obtain a first diameter, using the first diameter as a first sphere, performing collision detection on the first sphere and the blood vessel model, and stopping the flow if collision occurs, wherein the first focus cannot perform an ablation operation; otherwise, taking the sphere center of the first sphere as a target ablation point, taking the radius of the first sphere as a target ablation distance, and stopping the flow.

Because the human tissue has certain heat dissipation capability and the temperature of the ablation target position cannot be too high, when the temperature of the target position reaches the highest, the temperature of the ablation center outwards can be slowly reduced, the ablation effect has certain limit, and the maximum distance which can be achieved by ablation is called the maximum ablation distance.

In addition, since there is a certain error in the medical image and some burr of the tumor cells is overhanging when diffusing, in order to ensure the ablation effect, the actual ablation range should be larger than the focus range, as shown by the focus No. 3 in fig. 2, the dotted line is the actual range of the tumor, but the ablation should use the range shown by the solid line. As shown in fig. 4, it is necessary to extend a certain redundant distance (indicated by thick black lines) at the longest end of the tumor.

The maximum distance is less than or equal to 2 x (maximum ablation distance-redundant distance), which means that the ablation range of the ablation needle can cover the whole tumor, and only the ablation range needs to be set according to the size of the tumor. The longest tumor distance is the maximum distance, redundant distances are respectively added at two ends of the maximum distance line segment to obtain a first diameter, and the first diameter is used as a first sphere to cover the whole ablation area.

Further, since the area covered by the whole sphere is affected during ablation, when a critical blood vessel exists in the area covered by the sphere, the operation cannot be performed, so that further, collision detection is performed on the first sphere and the blood vessel model, if collision occurs, the ablation operation cannot be performed on the first focus, and the flow is stopped. Because the focus model and the blood vessel model are positioned in the same coordinate system and expressed by the same scale, only the coordinate of the blood vessel model is required to be judged whether to fall into the sphere range. When a blood vessel falls into an ablation sphere, the lesion is not suitable for an ablation operation, and all subsequent operations are directly stopped.

When no important blood vessel falls into the ablation sphere, the operation can be safely performed, the sphere center is the target ablation point, namely the insertion point of the ablation needle, the radius of the sphere is the target ablation distance, and the target ablation distance can be controlled by controlling the temperature, the ablation time and the like of the ablation target position, so that the optimal ablation point and the optimal ablation distance are found under the condition, and the subsequent flow is stopped at the moment.

Step S5, when the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), searching a second coordinate point with the nearest distance of 2 x (maximum ablation distance-redundant distance) from the first coordinate point, connecting the first coordinate point with the second coordinate point, respectively adding redundant distances at two ends of the connecting line to obtain a second diameter, using the second diameter as a second sphere, performing collision detection on the second sphere and the vascular model, and stopping the flow if collision occurs, wherein the first focus cannot perform an ablation operation; otherwise, taking the sphere center of the second sphere as a target ablation point, and taking the radius of the second sphere as a target ablation distance.

When the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), the lesion is larger, the ablation range is smaller, and one ablation needle cannot cover the whole lesion completely, as shown in fig. 5, at this time, one ablation needle can only cover the maximum range that can be treated by the ablation, so that by searching a second coordinate point with the nearest distance of 2 x (maximum ablation distance-redundant distance) from the first coordinate point, the maximum range that can be covered by one ablation needle is determined by connecting the first coordinate point with the second coordinate point, and the redundant distance is respectively added at two ends of the connecting line to obtain a second diameter, and the second diameter is taken as the range of one ablation needle.

Step S6, subtracting the second sphere from the first focus model, and returning to the step S3.

To facilitate subsequent treatment, the location in the lesion model that has been covered by the first ablation needle is removed, as shown in fig. 6, and the other location is where there is no ablation, requiring treatment with the other ablation needle. And thus returns to step S3 to determine the position of the next ablation needle. As shown in fig. 7, the extent of the second ablation needle is determined by again running steps S3-S5; as shown in fig. 8, proceeding again to step S6, only a small portion remains uncovered by the ablation needle; the operation returns to step S3 again, as shown in fig. 9, where the lesion is smaller and may be covered by an ablation needle, so that the operation is stopped until step S4; as shown in fig. 10, the lesion defines three ablation spheres (indicated by dotted lines), the centers of the three spheres, i.e., the locations where the three ablation needles are inserted, and the radii of the three spheres, i.e., their respective ablation ranges.

Through the steps, the insertion position and the ablation range of the ablation needle are accurately determined, manual intervention is reduced, and accuracy is improved.

In another implementation, the present invention also provides an ablation determination system, comprising the following modules:

the model building module is used for modeling the surgical target position before the surgery to obtain a three-dimensional model of the target position;

the model extraction module is used for extracting a first focus model and a blood vessel model from the three-dimensional model of the target position, wherein the first focus model and the blood vessel model are represented by the same coordinate system;

a first calculation module, configured to randomly select a first coordinate point on the surface of the first lesion model, preferentially search surface points of a nearby lesion model with breadth from the first coordinate point, and determine a maximum distance between the first coordinate point and the surface points;

the first determining module is used for respectively adding redundant distances to two ends of the maximum distance line segment to obtain a first diameter when the maximum distance is smaller than or equal to 2 x (maximum ablation distance-redundant distance), taking the first diameter as a first sphere, performing collision detection on the first sphere and the blood vessel model, and stopping the flow if collision occurs, the first focus can not perform ablation operation; otherwise, taking the sphere center of the first sphere as a target ablation point, taking the radius of the first sphere as a target ablation distance, and stopping the flow;

the second determining module is used for searching a second coordinate point with the nearest distance of 2 x (maximum ablation distance-redundant distance) from the first coordinate point when the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), connecting the first coordinate point with the second coordinate point, respectively adding redundant distances at two ends of the connecting line to obtain a second diameter, using the second diameter as a second sphere, performing collision detection on the second sphere and the blood vessel model, and stopping the flow, wherein if collision occurs, the first focus can not perform an ablation operation; otherwise, taking the sphere center of the second sphere as a target ablation point, and taking the radius of the second sphere as a target ablation distance;

and a third determining module for subtracting the second sphere from the first lesion model and returning to the first calculating module.

It should be noted that the detailed implementation principle and further improvement of the ablation determining system are the same as those of the ablation determining method, and the detailed description will not be given in this embodiment, and those skilled in the art may implement the detailed implementation in the ablation determining system according to the prior art ablation determining method.

Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.

The present invention is not limited to the specific partial module structure described in the prior art. The prior art to which this invention refers in the preceding background section as well as in the detailed description section can be used as part of the invention for understanding the meaning of some technical features or parameters. The protection scope of the present invention is subject to what is actually described in the claims.

Claims

1. A method of ablation determination, the method comprising the steps of:

step S1, modeling a surgical target position before surgery to obtain a three-dimensional model of the target position;

s2, extracting a first focus model and a blood vessel model from the three-dimensional model of the target position, wherein the first focus model and the blood vessel model are represented by the same coordinate system;

step S3, randomly selecting a first coordinate point on the surface of the first focus model, preferentially searching the surface points of the nearby focus model according to the breadth from the first coordinate point, and determining the maximum distance between the first coordinate point and the surface points;

step S4, when the maximum distance is smaller than or equal to 2 x (maximum ablation distance-redundant distance), adding redundant distances to two ends of the maximum distance line segment to obtain a first diameter, using the first diameter as a first sphere, performing collision detection on the first sphere and the blood vessel model, and stopping the flow if collision occurs, wherein the first focus cannot perform an ablation operation; otherwise, taking the sphere center of the first sphere as a target ablation point, taking the radius of the first sphere as a target ablation distance, and stopping the flow;

step S5, when the maximum distance is greater than 2 x (maximum ablation distance-redundant distance), searching a second coordinate point with the nearest distance of 2 x (maximum ablation distance-redundant distance) from the first coordinate point, connecting the first coordinate point with the second coordinate point, respectively adding redundant distances at two ends of the connecting line to obtain a second diameter, using the second diameter as a second sphere, performing collision detection on the second sphere and the vascular model, and stopping the flow if collision occurs, wherein the first focus cannot perform an ablation operation; otherwise, taking the sphere center of the second sphere as a target ablation point, and taking the radius of the second sphere as a target ablation distance;

2. A method of ablation determination as in claim 1, wherein: the three-dimensional model is built by CT or MRI techniques.

3. A method of ablation determination as in claim 1, wherein: the first lesion model only holds surface data for lesions.

4. A method of ablation determination as in claim 1, wherein: the vessel model retains only vessels having diameters greater than a first threshold.

5. A method of ablation determination as in claim 1, wherein: the first lesion model and the vessel model are expressed on the same coordinate system at the same scale.

6. An ablation determination system, characterized in that the system comprises the following modules:

7. An ablation determining system as recited in claim 6, wherein: the three-dimensional model is built by CT or MRI techniques.

8. An ablation determining system as recited in claim 6, wherein: the first lesion model only holds surface data for lesions.

9. An ablation determining system as recited in claim 6, wherein: the vessel model retains only vessels having diameters greater than a first threshold.

10. An ablation determining system as recited in claim 6, wherein: the first lesion model and the vessel model are expressed on the same coordinate system at the same scale.