CN-122005082-A - Puncture operation path planning method and device

CN122005082ACN 122005082 ACN122005082 ACN 122005082ACN-122005082-A

Abstract

The invention provides a puncture operation path planning method and device, the method comprises the steps of constructing a three-dimensional geometric model for a lung based on CT image data, determining a puncture needle start point and a lesion target point end point in the three-dimensional geometric model, establishing a reference coordinate system on the three-dimensional geometric model according to the puncture needle start point and the lesion target point end point, performing spatial sampling on a puncture path constructed by the puncture needle start point and the lesion target point end point, acquiring a plurality of path sampling points, extracting point clouds on the surface of the three-dimensional geometric model, establishing a spatial index structure, calculating the minimum spatial distance from each path sampling point to the three-dimensional geometric model based on the spatial index structure, comparing the minimum spatial distance with a preset safety threshold, and determining the safety of the puncture path. By adopting the technical scheme, the safety, accuracy and clinical controllability of puncture path planning can be improved.

Inventors

XIE HANG
HUANG ZHIJUN
QIAN KUN

Assignees

浙江柳叶刀机器人有限公司

Dates

Publication Date: 20260512
Application Date: 20260206

Claims (10)

1. A method of planning a puncture path, comprising: constructing a three-dimensional geometric model for the lung based on the CT image data; Determining a puncture needle start point and a lesion target point end point in the three-dimensional geometric model, and establishing a reference coordinate system on the three-dimensional geometric model according to the puncture needle start point and the lesion target point end point; performing spatial sampling on a puncture path constructed by the puncture needle inlet starting point and the lesion target point end point to obtain a plurality of path sampling points; Extracting the point cloud of the three-dimensional geometric model surface and establishing a spatial index structure; Calculating the minimum space distance from each path sampling point to the three-dimensional geometric model based on the space index structure; and comparing the minimum space distance with a preset safety threshold value to determine the safety of the puncture path.
2. The method of planning a path for a penetrating procedure of claim 1, wherein the starting point of penetration has a first coordinate value and the ending point of the lesion target has a second coordinate value; establishing a reference coordinate system on the three-dimensional geometric model according to the puncture needle insertion starting point and the lesion target point end point, wherein the reference coordinate system comprises the following steps: Determining a path direction vector of the puncture path according to the first coordinate value and the second coordinate value; Carrying out unitization processing on the path direction vector to determine a unit path direction vector; Determining an auxiliary vector based on the z-component in the unit path direction vector; determining a first vector orthogonal to the unit path direction vector according to the unit path direction vector and the auxiliary vector, and performing unitization processing to determine the first unit direction vector; Determining a second vector according to the first vector and the unit path direction vector, and executing unitization processing to determine a second unit direction vector; and taking the midpoint of the puncture needle insertion starting point and the midpoint of the lesion target point end point as origin points, and respectively taking the unit path direction vector, the second unit direction vector and the first unit direction vector as axes to obtain the reference coordinate system.
3. The method of planning a puncture path according to claim 1, wherein the extracting the point cloud of the three-dimensional geometric model surface and establishing a spatial index structure comprises: Traversing all triangular patches of the three-dimensional geometric model, and extracting point clouds at least comprising patch vertexes, patch centers of gravity and side midpoints to form a point cloud set, wherein each point cloud has respective corresponding pixel index coordinates; Converting the pixel index coordinates of each point cloud to the reference coordinate system, and determining corresponding conversion point clouds; and carrying out recursion division on the conversion point cloud according to a plurality of preset space coordinate directions based on the conversion point cloud, and selecting a point corresponding to the middle position of the point cloud data in the current coordinate direction in each division as a division threshold value to construct a corresponding child node and form the space index structure.
4. The method of claim 3, wherein the pixel index of the point cloud is used to characterize the relative position of the point cloud in the CT image data; the method comprises the steps of converting pixel index coordinates of each point cloud to a reference coordinate system, and determining corresponding converted point clouds, wherein the method comprises the steps of obtaining space coordinate system information corresponding to CT images, wherein the space coordinate system information at least comprises initial position parameters of image space and space sampling intervals in three orthogonal directions; the recursively dividing the conversion point cloud according to a plurality of preset space coordinate directions based on the conversion point cloud, selecting a point corresponding to the middle position of the point cloud data in the current coordinate direction as a division threshold value in each division to construct a corresponding sub-node and form the space index structure, and the method comprises the following steps: Determining a dividing point corresponding to the middle position of the conversion point cloud in the coordinate direction by taking a first preset coordinate direction as an initial dividing direction, taking the value of the dividing point cloud in the coordinate direction as a dividing threshold, dividing the conversion point cloud into a first sub-point cloud and a second sub-point cloud according to the dividing threshold, wherein the first sub-point cloud comprises points with values smaller than the dividing threshold in the first preset coordinate direction, the second sub-point cloud comprises points with values larger than the dividing threshold in the first preset coordinate direction, and respectively constructing the first sub-point cloud and the second sub-point cloud as left and right sub-nodes of an index structure; executing the dividing operation by taking a second preset coordinate direction as a dividing direction for the first sub-point cloud, and executing the dividing operation by taking a third preset coordinate direction as a dividing direction for the second sub-point cloud; Performing the dividing operation on each sub-point cloud recursively according to a preset coordinate direction sequence to build an index structure layer by layer; And stopping continuous division of the sub-point cloud when the number of points contained in any sub-point cloud is smaller than or equal to a preset threshold value, and determining the sub-point cloud as a leaf node.
5. The method of claim 3, wherein calculating a minimum spatial distance from each path sampling point to the three-dimensional geometric model based on the spatial index structure comprises: For each path sampling point, performing traversal operation on the spatial index structure, determining a nearest neighboring point to the path sampling point, and taking a distance value as an initial implicit distance; in response to the neighboring point not being located inside the triangular patch, taking the initial implicit distance as the minimum spatial distance; And determining a new distance value as the minimum space distance according to the coordinates of one vertex of the triangular patch where the adjacent point is located, the normal vector of the triangular patch and the path sampling point in response to the adjacent point being located inside the triangular patch.
6. The method of claim 5, wherein determining whether the point of proximity is within the triangular patch is performed by: Acquiring basic information of the triangular patch, wherein the triangular patch is uniquely determined by three non-collinear vertexes, and each vertex corresponds to a three-dimensional space coordinate; Based on the three-dimensional space coordinates of the three vertexes, the normal vector of the triangular patch is obtained through vector cross multiplication operation; according to the direction relation between the normal vector and each coordinate axis in the three-dimensional coordinate system, selecting a coordinate plane with the smallest included angle with the normal vector as a projection plane; Synchronously projecting the adjacent points and three vertexes of the triangular patch from a three-dimensional space to the projection plane to obtain corresponding two-dimensional point coordinates and two-dimensional triangles; In the projection plane, emitting rays along a preset direction by taking the two-dimensional point coordinates as a starting point, and counting the number of intersection points between the rays and each side of the two-dimensional triangle; Judging the inclusion relation between the space points and the triangular patches according to the number of the intersection points, when the number of the intersection points is odd, determining that the space points are positioned inside the triangular patches, and when the number of the intersection points is even or the two-dimensional points are overlapped with the two-dimensional triangle boundary, determining that the space points are positioned outside or on the triangular patches; the new distance value is determined as follows: Wherein, the Coordinates of one of the vertices of the triangular patch; Is the normal vector of the triangular patch; Is a path sampling point.
7. The method of planning a puncture path according to claim 1, wherein comparing the minimum spatial distance with a preset safety threshold value, determining the safety of the puncture path, comprises: Determining that the puncture path is unsafe in response to the fact that the minimum spatial distance corresponding to any path sampling point is smaller than the lower limit of the preset safety threshold; Outputting an early warning indication in response to the minimum space distance corresponding to all the path sampling points being within the preset safety threshold range; And determining that the puncture path is a safe path in response to the minimum spatial distance corresponding to all path sampling points being greater than the upper limit of the preset safety threshold range.
8. The method of planning a penetration surgical path according to claim 1 or 7, wherein one or more of the following are satisfied: generating a safety boundary adapting to the gesture of the puncture path by taking the puncture path as a central axis in response to the puncture path being a safety path; Responding to the puncture path as a safety path, taking the puncture path as a selected path, setting the selected path and the corresponding safety boundary thereof to a first color, and setting other areas to a second color; after the selected path is determined, calculating the slice index of the start key point or the end key point of the path in the three-dimensional image, and determining the coordinate positions of the image view in three directions according to the slice index, the corresponding slice spacing and the minimum coordinate values of all directions, so that the image view is automatically positioned to the key point and kept synchronous with the path position in real time.
9. The puncture path planning method according to claim 8, wherein the generating a safety boundary adapted to the posture of the puncture path with the puncture path as a central axis comprises: taking the center position of the puncture path as the center of the safety boundary geometry, and taking the total length of the puncture path as the height of the safety boundary geometry; determining a radius of a safety boundary geometry based on a spatial dimension of the lesion tissue and a chest wall thickness, wherein the radius is adjusted according to the chest wall thickness on the basis of a preset basic safety radius; a cylinder is used as a basic form of the safety boundary geometry; performing rotary transformation on the cylinder based on the reference coordinate system to enable the axis direction of the cylinder to be consistent with the puncture path direction; On the basis of completing rotation transformation, carrying out translation transformation on the cylinder to enable the center position of the cylinder to coincide with the center position of the puncture path, thereby realizing the matching of the position and the gesture of the safety boundary geometry in the three-dimensional space; Generating a safety boundary geometric model which is accurately aligned with the puncture path by carrying out space transformation on the initial vertex of the cylinder; constructing an implicit distance constraint model for describing the distance relation between a space point and the surface of the safety boundary geometrical body; And judging the point cloud on the surface of the three-dimensional geometric model based on the implicit distance constraint model, determining that the safety boundary is attached to the surface of the three-dimensional geometric model when the point cloud is positioned in the safety boundary range, and realizing attachment optimization of the safety boundary and the surface of the three-dimensional geometric model by limiting an adaptation error between the safety boundary and the surface of the three-dimensional geometric model in a preset threshold range.
10. A puncture path planning device, comprising: the constructing unit is used for constructing a three-dimensional geometric model for the lung based on the CT image data; The establishing unit is used for determining a puncture needle start point and a lesion target point end point in the three-dimensional geometric model, and establishing a reference coordinate system on the three-dimensional geometric model according to the puncture needle start point and the lesion target point end point; the sampling unit is used for performing space sampling on a puncture path constructed by the puncture needle inlet starting point and the lesion target point end point to obtain a plurality of path sampling points; The extraction unit is used for extracting the point cloud of the three-dimensional geometric model surface and establishing a spatial index structure; the planning unit is used for calculating the minimum space distance from each path sampling point to the three-dimensional geometric model based on the space index structure, comparing the minimum space distance with a preset safety threshold value and determining the safety of the puncture path.

Description

Puncture operation path planning method and device Technical Field The invention relates to the technical field of surgical path planning, in particular to a puncture surgical path planning method and device. Background The lung puncture operation is a core minimally invasive technology for diagnosing lung lesions (such as nodules and tumors), and the core requirement of operation planning is to precisely generate a puncture path from the chest wall surface to lesion tissues, avoid important anatomical structures such as lung blood vessels and bronchi, and establish a safety boundary to guide the operation range of a puncture needle. In the existing lung puncture path planning technology, the main stream scheme is that a doctor manually marks a puncture starting point (chest wall surface point) and a puncture ending point (lesion target point) on a two-dimensional CT slice, a puncture path is generated through a simple space two-point connecting line, and the path length is calculated only by adopting a basic Euclidean distance formula. However, the puncture path planning method does not consider the individuation form of the lung tissues and the space posture difference of the puncture paths, and needs to be improved. Disclosure of Invention In view of the above, the invention provides a puncture operation path planning method and device, which can improve the safety, accuracy and clinical controllability of puncture path planning. In a first aspect, the present invention provides a puncture path planning method, including: constructing a three-dimensional geometric model for the lung based on the CT image data; Determining a puncture needle start point and a lesion target point end point in the three-dimensional geometric model, and establishing a reference coordinate system on the three-dimensional geometric model according to the puncture needle start point and the lesion target point end point; performing spatial sampling on a puncture path constructed by the puncture needle inlet starting point and the lesion target point end point to obtain a plurality of path sampling points; Extracting the point cloud of the three-dimensional geometric model surface and establishing a spatial index structure; Calculating the minimum space distance from each path sampling point to the three-dimensional geometric model based on the space index structure; and comparing the minimum space distance with a preset safety threshold value to determine the safety of the puncture path. Optionally, the puncture needle insertion starting point has a first coordinate value, and the lesion target point end point has a second coordinate value; establishing a reference coordinate system on the three-dimensional geometric model according to the puncture needle insertion starting point and the lesion target point end point, wherein the reference coordinate system comprises the following steps: Determining a path direction vector of the puncture path according to the first coordinate value and the second coordinate value; Carrying out unitization processing on the path direction vector to determine a unit path direction vector; Determining an auxiliary vector based on the z-component in the unit path direction vector; determining a first vector orthogonal to the unit path direction vector according to the unit path direction vector and the auxiliary vector, and performing unitization processing to determine the first unit direction vector; Determining a second vector according to the first vector and the unit path direction vector, and executing unitization processing to determine a second unit direction vector; and taking the midpoint of the puncture needle insertion starting point and the midpoint of the lesion target point end point as origin points, and respectively taking the unit path direction vector, the second unit direction vector and the first unit direction vector as axes to obtain the reference coordinate system. Optionally, the extracting the point cloud of the three-dimensional geometric model surface and establishing a spatial index structure includes: Traversing all triangular patches of the three-dimensional geometric model, and extracting point clouds at least comprising patch vertexes, patch centers of gravity and side midpoints to form a point cloud set, wherein each point cloud has respective corresponding pixel index coordinates; Converting the pixel index coordinates of each point cloud to the reference coordinate system, and determining corresponding conversion point clouds; and carrying out recursion division on the conversion point cloud according to a plurality of preset space coordinate directions based on the conversion point cloud, and selecting a point corresponding to the middle position of the point cloud data in the current coordinate direction in each division as a division threshold value to construct a corresponding child node and form the space index structure. Optionally, the pixel index of the p