Method and system for positioning tissue pathological section image

Abstract

The invention discloses a tissue pathological section image positioning method and system. The positioning method comprises the following steps: S1, fixing tissue in paraffin to form a paraffin block; s2, the paraffin block is cut to obtain a plurality of tissue slices, in the cutting process, laser is used for conducting ablation on each tissue slice to form at least three mark points, and the first coordinates of all the mark points are recorded; s3, acquiring a slice image of the tissue slice with the mark point; and S4, obtaining a second coordinate of each mark point in the slice image, comparing the second coordinate with the first coordinate, and positioning the slice image based on a comparison result. The laser is utilized to directly and accurately ablate a plurality of mark points on each tissue slice, the marking efficiency is high, the accuracy is high, accumulated errors are greatly reduced, the positioning efficiency is improved, a large number of thinner tissue pathological slices can be obtained during tissue cutting, and the accuracy of tissue three-dimensional reconstruction is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of medical artificial intelligence technology, and in particular to a method and system for positioning a tissue pathology section image. Background Art

[0002] In recent years, 3D reconstruction technology has been widely used in clinical diagnosis and treatment of hepatobiliary surgery, plastic surgery, maxillofacial surgery, orthopedics, etc. 3D reconstruction technology can obtain all-round, three-dimensional, intelligent dynamic and static images, clearly showing the spatial position, morphological structure and anatomical relationship of the lesion with surrounding organs, which is helpful for preoperative planning, measurement, calculation, simulation of surgical operations, and also helps to formulate individualized treatment plans and improve surgical accuracy and safety.

[0003] In the process of three-dimensional reconstruction of tissues, after a series of processing is performed on the slice images of each tissue pathological slice, each slice image needs to be positioned, and the accuracy of positioning will affect the accuracy of the three-dimensional reconstruction of the tissue. The inventor team disclosed a method for three-dimensional reconstruction of tissues based on tumor infiltration area marking in patent CN117011462A. In this method, after obtaining the slice images of the tissue pathological slices using a pathology scanner, three marking points are determined on the slice images, and each slice image is rotated and flipped according to the positional relationship of the three marking points, so that the angles of each slice image are roughly the same, thereby achieving the positioning of each slice image.

[0004] In order to observe more cross-sectional information of the tissue, the tissue pathology slices can be cut thin enough (for example, 2 μm), which significantly increases the number of slice images that need to be positioned. However, the existing slice image positioning method requires a series of algorithms to generate three marking points on each slice image, which reduces the efficiency of positioning. In addition, the three marking points on each slice image are not based on the same coordinate system to adjust the slice image, but adjust the slice image according to the relative position between the three marking points, so errors will inevitably occur. When the number of slice images is large, the cumulative error will seriously affect the accuracy of positioning, and then affect the accuracy of three-dimensional reconstruction. Therefore, the efficiency and accuracy of the existing slice image positioning method are difficult to apply to large-scale slice image processing, and the accuracy of three-dimensional reconstruction of tissues needs to be further improved. Summary of the invention

[0005] An object of the present invention is to provide a method for positioning tissue pathology slice images for three-dimensional reconstruction of tumor tissue, so as to solve the problems of low efficiency, large cumulative error and poor accuracy of the slice image positioning method in the prior art when used for large-scale slice image processing, to achieve efficient and high-precision positioning of the slice image, to allow a large number of thinner tissue pathology slices to be obtained during tissue cutting, and to significantly improve the accuracy of tissue three-dimensional reconstruction.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for positioning a tissue pathology slice image comprises the following steps:

[0008] S1: Fix the tissue in paraffin to form a paraffin block;

[0009] S2: cutting the paraffin block to obtain a plurality of tissue slices. During the cutting process, ablation is performed on each tissue slice by laser to form at least three marking points, and the first coordinates of each marking point are recorded;

[0010] S3: Acquisition of slice images of tissue slices with marked points;

[0011] S4: Acquire second coordinates of each marking point in the slice image, compare the second coordinates with the first coordinates, and locate the slice image based on the comparison result.

[0012] In the technical solution, the tissue to be three-dimensionally reconstructed is wrapped with paraffin to obtain a paraffin block. In one or more embodiments, the paraffin block can be pre-processed, for example, the excess paraffin on the paraffin block is cut off until the tissue is exposed on the end surface of the paraffin block.

[0013] In the present technical solution, a microtome is used to cut a paraffin block to obtain a number of tissue slices. During the cutting process, a laser is used to ablate each tissue slice to form a number of marking points. In some embodiments, the end face of the paraffin block or the cross section after cutting is laser ablated, and after the marking points are ablated on the end face or the cross section, the tissue slice with the marking points is cut from the paraffin block. In one or more embodiments, the depth of laser ablation, that is, the length in the direction perpendicular to the cross section, is an integer multiple of the thickness of the tissue slice to be cut, thereby improving the marking efficiency. In some preferred embodiments, the depth of laser ablation is equal to the thickness of the tissue slice to be cut, thereby ensuring that the marking points on each tissue slice can be located within the tissue contour.

[0014] In the technical solution, the laser or the emitting unit of the laser can be controlled to move so as to ablate marking points at different positions on the cross section of the paraffin block. The control unit of the laser or the laser itself has a two-dimensional coordinate system, so as to move the laser to the first coordinate point based on the two-dimensional coordinate system. The laser ablates the marking point at the first coordinate point and records the first coordinate corresponding to the marking point.

[0015] In the technical solution, after forming the marking points on each tissue slice, each tissue slice can be scanned by a pathology scanner to obtain the slice images corresponding to each tissue slice, and number them according to the order of cutting. In some embodiments, a series of operations can also be performed on the slice images, for example, in CN117011462A, a closed infiltration area is marked on the slice image.

[0016] In the present technical solution, the second coordinates of the marked point on the tissue slice in the slice image are identified. The second coordinate system used by the second coordinate may be the same as or different from the first coordinate system used by the first coordinate. If the second coordinate system is the same as the first coordinate system, the second coordinate and the first coordinate can be directly compared. If the second coordinate system is different from the first coordinate system, based on the spatial relationship between the two coordinate systems, the second coordinate in the second coordinate system is converted to the first coordinate system, and then the second coordinate is compared with the first coordinate. In the present technical solution, by comparing the second coordinates on the slice image with the recorded first coordinates one by one, each second coordinate is moved to a first coordinate that is close to or the same as it, and the rotation and flipping of the slice image is completed, so as to achieve accurate positioning of the slice image.

[0017] In the present technical solution, a laser is used to directly and accurately ablate a number of marking points on each tissue slice, and the marking efficiency and accuracy are high; more importantly, the first coordinates of the marking points on different tissue slices share the same two-dimensional coordinate system. Therefore, after the second coordinate is identified on the slice image, the slice image can be rotated and flipped based on the two-dimensional coordinate system by comparing the second coordinate with the first coordinate, so as to locate the position of the tissue slice before it is cut, which greatly reduces the cumulative error and improves the positioning efficiency, is conducive to obtaining a large number of thinner tissue pathology slices when cutting tissue, and significantly improves the accuracy of tissue three-dimensional reconstruction.

[0018] Furthermore, in step S2, before cutting the paraffin block each time, a cross-sectional image of the cross section of the part to be cut of the paraffin block is collected, a tissue contour line is extracted from the cross-sectional image, a first coordinate is determined within the tissue contour line, a laser is ablated at the first coordinate to form a marking point, and the part to be cut is cut to obtain a tissue slice with the marking point.

[0019] In the technical solution, before each tissue slice is cut from the paraffin block, a camera can be used to shoot the portion of the paraffin block to be cut, that is, the cross section of the tissue slice, to obtain a cross-sectional image of the cross section. Subsequently, a tissue contour line is extracted from the cross-sectional image, and the tissue contour line is the boundary line between the tissue and the paraffin.

[0020] In the present technical solution, the first coordinates of the marking points to be formed are determined within the tissue contour. The first coordinates of each marking point may be random or may have a certain correlation, for example, the geometric center of the polygon formed by connecting each marking point coincides with the centroid of the tissue contour. In some preferred embodiments, each marking point is close to the center of the tissue slice. This is because, compared with the edge area of ​​the tissue slice, the center and nearby areas of the tissue slice are less deformed during the cutting process, thereby reducing the offset or deformation of the marking point during the cutting process.

[0021] In the technical solution, the laser ablates a certain depth at the determined first coordinate, and the ablation depth is preferably the same as the thickness of the tissue slice to be cut, or the ablation depth is slightly less than the thickness of the tissue slice, thereby allowing the position of the marking point on each tissue slice to be different. After the marking point is formed, the tissue slice is cut from the paraffin block to obtain a tissue slice with the marking point.

[0022] In this technical solution, the first coordinate is selected based on the tissue contour line, so that all the marking points can be located on the tissue section, thereby overcoming the problem that some marking points formed on the paraffin are difficult to be collected on the section image because the paraffin needs to be melted before the section image is collected.

[0023] Furthermore, in step S2, the method of determining the first coordinate includes the following steps:

[0024] The centroid of the tissue contour is obtained, and first coordinates for forming a marking point are determined around the centroid, and the geometric center of a polygon formed by connecting lines of the first coordinates is located near the centroid.

[0025] In the present technical solution, the positions of the marking points on the same tissue slice are related. Specifically, after obtaining the tissue contour line, the centroid of the tissue contour line is calculated based on the coordinates of several points on the tissue contour line. m The calculation formula is Among them, x i is the coordinate of any point on the tissue contour line, m i is the weight of any point on the tissue contour line. In some embodiments, the weights of all points on the tissue contour line are the same.

[0026] In the technical solution, at least three first coordinates can be randomly generated within the tissue contour. A polygon can be obtained by connecting the first coordinates, and the vertices of the polygon are located at the first coordinates. The geometric center of the polygon is located near the centroid. In some embodiments, the geometric center of the polygon can coincide with the centroid.

[0027] In this technical solution, by setting the geometric center of the polygon formed by each marking point near the centroid of the tissue contour line, the marking points can be evenly distributed on the tissue slice, avoiding serious local damage to the tissue slice caused by the concentration of marking points.

[0028] As a preferred implementation of the first coordinate selection in the present invention, in step S2, the method of determining the first coordinate includes the following steps:

[0029] For a first tissue slice, a first centroid of a first tissue contour line is obtained, and first coordinates for forming a marking point are determined around the first centroid, wherein the geometric center of a polygon formed by connecting lines of the first coordinates coincides with the first centroid;

[0030] For other subsequent tissue slices, the first coordinates of each marking point of the adjacent previous tissue slice are obtained, and after each first coordinate is moved in the same direction by the same distance, it is determined whether all the first coordinates after the movement are located within the second tissue contour line of the current tissue slice;

[0031] If yes, the first coordinates after the movement are used as the first coordinates of the current tissue slice;

[0032] If not, the second centroid of the second tissue contour is obtained, the geometric center of the polygon is moved to coincide with the second centroid, the polygon is rotated, and the coordinates of each vertex of the polygon are used as the first coordinates of the current tissue slice.

[0033] In this technical solution, when determining the first coordinate on the first tissue slice, the first coordinate is randomly generated within the first tissue contour line, and the geometric center of the polygon formed by the first coordinate connection line coincides with the first centroid of the first tissue contour line.

[0034] In the present technical solution, when determining the second to last tissue slice, first obtain the first coordinate selected by the previous tissue slice, and then determine the first coordinate of the current tissue slice through the first coordinate selected by the previous tissue slice. For example, when determining the second tissue slice, first obtain the first coordinate used by the first tissue slice, and then move each first coordinate in the same direction and the same distance to obtain the first coordinate after the move. Subsequently, determine whether all the first coordinates after the move are located within the tissue contour of the second tissue slice. If so, use the first coordinate after the move as the first coordinate of the second tissue slice. If at least one first coordinate is outside the tissue contour, obtain the second centroid of the tissue contour of the second tissue slice, and coincide the geometric center of the polygon with the second centroid, then rotate the polygon by a certain angle, and then select each vertex of the polygon as the first coordinate of the second tissue slice.

[0035] In the technical solution, the first coordinates on the next tissue slice are selected based on the first coordinates on the previous tissue slice, ensuring that the first coordinates on the two adjacent tissue slices do not overlap, which can effectively reduce the probability of laser ablation to the cancerous area of ​​the tissue slice. For example, if a first coordinate on the first tissue slice is located in the cancerous area, by moving the first coordinate on the second tissue slice a certain distance, the same position of the cancerous area on the second tissue slice can be avoided from being ablated again, effectively reducing the damage to the cancerous area caused by laser ablation.

[0036] Furthermore, among two adjacent tissue slices, if the first coordinates of the previous tissue slice are all located within the second tissue contour line after moving along the first direction, the first coordinates of the next tissue slice continue to move along the first direction.

[0037] In order to make the first coordinates of two adjacent tissue slices change more regularly and avoid the cancerous area in an orderly manner, in this technical solution, if the first coordinate is still located within the tissue contour of the current tissue slice after moving the first coordinate along the first direction, the next tissue slice will still move along the first direction when moving the first coordinate.

[0038] For example, after the first coordinate of the first tissue slice is moved along the first direction, if the first coordinate after the movement is still within the tissue contour of the second tissue slice, the first coordinate after the movement is used as the first coordinate of the second tissue slice. Next, when determining the first coordinate of the third tissue slice, the first coordinate of the second tissue slice is further moved along the first direction. This is repeated until, when determining a certain tissue slice, the first coordinate moved along the first direction is outside the tissue contour of the current tissue slice, and the geometric center of the polygon formed by the first coordinate is moved to the centroid of the tissue contour of the current tissue slice.

[0039] Furthermore, in the step S2, before cutting the tissue slice, a film is attached to the tissue slice.

[0040] Since the tissue slices cut from the paraffin block are very thin, they will be deformed and curled to varying degrees during the cutting process, which is not conducive to the subsequent extraction of marking points in the slice image.

[0041] In the technical solution, by attaching a film to the tissue slice, the strength of the tissue slice can be effectively improved, thereby reducing deformation, curling, and wrinkles during the cutting process, and reducing the probability of subsequent mark point offset. In some embodiments, a film can be attached to the tissue slice first, and then the mark point can be ablated by laser. In one or more embodiments, a laser can be used to ablate the mark point on the tissue slice first, and then a film can be attached to the tissue slice.

[0042] Furthermore, in step S4, an affine transformation matrix corresponding to the slice image is obtained based on the first coordinate and the second coordinate, the slice image is corrected using the affine transformation matrix, the third coordinate of each marking point in the corrected slice image is obtained, the third coordinate is compared with the first coordinate, and the corrected slice image is positioned based on the comparison result.

[0043] When the tissue slice is cut, the external force of the cutter will cause the tissue slice to deform, such as stretching and rotation. Moreover, this deformation will become more obvious as the thickness of the tissue slice decreases. The deformation of the tissue slice not only causes the second marking point on the slice image to be unable to completely correspond to the first marking point, and the slice image can only be roughly located by the similarity between the first marking point and the second marking point, but also the deformation of the tissue slice will affect the quality and accuracy of subsequent 3D reconstruction.

[0044] In order to solve the above problem, in this technical solution, after identifying the second coordinates of each marked point on the slice image, the affine transformation matrix corresponding to the slice image is obtained based on the second coordinates and the first coordinates. The calculation formula of the affine transformation matrix is:

[0045]

[0046] In the formula, x and y are the first coordinates (x, y), x' and y' are the second coordinates (x', y'), and among the six variables of the affine transformation matrix, s x and y are variables that control scaling and flipping along the X and Y axes, respectively. x and α y are the variables that control the rotation along the X-axis and Y-axis, respectively. x and t y are variables that control translation along the X and Y axes respectively.

[0047] Based on the first and second coordinates of the marking points on the tissue slice, the six variables in the affine transformation matrix can be obtained by solving the six-variable linear equation. The slice image can be corrected by applying the affine transformation matrix to each pixel in the slice image. Next, the third coordinate of each marking point is identified in the corrected slice image. The corrected third coordinate can better match the first coordinate, thereby achieving accurate positioning of the slice image. In addition, the slice image corrected based on the first coordinate can better restore the shape of the tissue slice before it is cut, which is conducive to improving the quality and accuracy of subsequent three-dimensional reconstruction.

[0048] Furthermore, if there are at least four marking points on the slice image, the polygonal area formed by the at least four marking points is divided into at least two triangular areas, and an affine transformation matrix of each triangular area is obtained;

[0049] For pixel points located within the triangular region on the slice image, the pixel points are processed using an affine transformation matrix corresponding to the triangular region;

[0050] For a pixel point on the slice image that is outside the triangular region, the pixel point is processed using an affine transformation matrix corresponding to the triangular region that is closest to the pixel point.

[0051] When there are three marking points on the tissue slice, the six variables of the affine transformation matrix can be calculated using the first coordinates and the second coordinates of the three marking points to achieve the correction of the slice image. In order to improve the accuracy of the correction, more marking points can be set.

[0052] In the present technical solution, there are at least four marking points on the slice image. At least four marking points can form polygons such as quadrilaterals, pentagons, and hexagons. Before solving the affine transformation matrix, the polygonal area can be divided into multiple triangular areas. For example, a quadrilateral can be divided into two triangular areas, and a pentagon can be divided into three triangular areas. After division, the first coordinates and the second coordinates of the three marking points of each triangular area are used to calculate the affine transformation matrix. Next, the affine transformation matrix corresponding to the triangular area is used to correct the pixel points located in the triangular area. For the pixel points that do not belong to any triangular area, the affine transformation matrix of the triangular area closest to the pixel point is used to correct the pixel point, thereby completing the correction of the entire slice image.

[0053] In this technical solution, more marking points are used to delineate more triangular areas, allowing different triangular areas to be corrected by applying different affine transformation matrices, which can cope with more complex tissue deformations and further improve the accuracy of correction.

[0054] Furthermore, the polygonal area is divided into multiple groups of triangular areas using different division methods, an affine transformation matrix group of each group of triangular areas is obtained, the slice image is corrected using the affine transformation matrix group, a corrected tissue contour line on the corrected slice image is obtained, and the affine transformation matrix group is selected based on the corrected tissue contour line.

[0055] In the present technical solution, different methods are used to divide the polygonal area into several triangular areas. For example, two different diagonal lines of a quadrilateral can be connected to divide the quadrilateral into a first group of triangular areas and a second group of triangular areas. Afterwards, the affine transformation matrix is ​​calculated for the two triangular areas in the first group of triangular areas respectively, and the slice image is processed by the affine transformation matrix to obtain the first corrected image; the affine transformation matrix is ​​calculated for the two triangular areas in the second group of triangular areas respectively, and the slice image is processed by the affine transformation matrix to obtain the second corrected image. The corrected tissue contour lines of the first and second corrected images are extracted, compared with the tissue contour lines of the cross-sectional image, and the corrected image whose shape of the corrected tissue contour line is closer to the tissue contour line of the cross-sectional image is used as the corrected slice image. By adopting different triangular area division methods and using the tissue contour lines of the cross-sectional image for selection, the accuracy of slice image correction can be further improved.

[0056] Another object of the present invention is to provide a positioning system for pathological slice images, the positioning system comprising:

[0057] A laser, used for emitting laser light to form at least three marking points on the tissue slice to be cut of the paraffin block, and recording the first coordinates of each marking point;

[0058] A microtome, used to cut tissue sections with marked points from paraffin blocks;

[0059] Pathology scanners for acquiring slice images of tissue sections with marker points;

[0060] The image processing unit obtains the second coordinates of each marking point in the slice image, compares the second coordinates with the first coordinates, and locates the slice image based on the comparison result.

[0061] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0062] 1. The present invention uses laser to directly ablate a number of marking points on each tissue slice accurately, and the marking efficiency and accuracy are high; the first coordinates of the marking points on different tissue slices share the same two-dimensional coordinate system, so after the second coordinate is identified on the slice image, the slice image can be rotated and flipped based on the two-dimensional coordinate system by comparing the second coordinate with the first coordinate, so as to locate the position of the tissue slice before it is cut, which greatly reduces the cumulative error and improves the positioning efficiency, is conducive to obtaining a large number of thinner tissue pathology slices when cutting tissue, and significantly improves the accuracy of tissue three-dimensional reconstruction.

[0063] 2. The present invention selects the first coordinate based on the tissue contour line, so that all the marking points are located on the tissue slice, thus overcoming the problem that some marking points formed on the paraffin are difficult to be collected on the slice image because the paraffin needs to be melted before collecting the slice image;

[0064] 3. The present invention can evenly distribute the marking points on the tissue slice by setting the geometric center of the polygon formed by each marking point near the centroid of the tissue contour line, thereby avoiding serious local damage to the tissue slice caused by the concentration of marking points;

[0065] 4. The present invention selects the first coordinates on the next tissue slice based on the first coordinates on the previous tissue slice, ensuring that the first coordinates on two adjacent tissue slices do not overlap, which can effectively reduce the probability of laser ablation to the cancerous area of ​​the tissue slice;

[0066] 5. The present invention calculates an affine transformation matrix based on the first coordinate and the second coordinate, and uses the affine transformation matrix to correct the slice image. The third coordinate of the corrected slice image can better match the first coordinate, thereby achieving accurate positioning of the slice image. In addition, the slice image corrected based on the first coordinate can better restore the shape of the tissue slice before being cut, which is conducive to improving the quality and accuracy of subsequent three-dimensional reconstruction.

[0067] 6. The present invention uses more marking points to delineate more triangular areas, allowing different triangular areas to be corrected using different affine transformation matrices, which can cope with more complex tissue deformations and further improve the accuracy of correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0069] Figure 1 is a flowchart of a positioning method in a specific embodiment of the present invention;

[0070] Figure 2 The method for determining the first coordinates of the first tissue slice to the fourth tissue slice in a specific embodiment of the present invention is exemplarily shown, wherein Figure 2 (a) to Figure 2 (d) The first to fourth tissue sections, respectively;

[0071] Figure 3 Schematically showing the positions of three marking points A, B, and C on (a) a cross-sectional image before cutting, (b) a slice image before correction, and (c) a slice image after correction in a specific embodiment of the present invention;

[0072] Figure 4Two ways of dividing the quadrilateral area in a specific embodiment of the present invention are shown;

[0073] Figure 5 It is a structural schematic diagram of the positioning system when the film sticking mechanism is in the initial state in a specific embodiment of the present invention;

[0074] Figure 6 It is a structural schematic diagram of the positioning system when the film sticking mechanism is in the film sticking state in a specific embodiment of the present invention;

[0075] Figure 7 It is a bottom view schematic diagram of a mobile station in a specific embodiment of the present invention.

[0076] Marks and corresponding parts names in the attached drawings:

[0077] 1-stage, 2-paraffin block, 3-blade, 4-film sticking mechanism, 5-second roller, 6-first roller, 7-reel, 8-film, 9-third roller, 10-fourth roller, 11-connecting rod, 12-film sticking wheel, 13-tissue section, 14-transverse linear guide pair, 15-longitudinal linear guide pair, 16-laser, 17-bearing, 18-moving stage. DETAILED DESCRIPTION

[0078] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0079] In the description of the present invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the scope of protection of the present invention.

[0080] Embodiment 1:

[0081] like Figure 1 A method for positioning a tissue pathology slice image is shown, comprising the following steps:

[0082] S1: Fix the tissue in paraffin to form a paraffin block;

[0083] S2: cutting the paraffin block to obtain a plurality of tissue slices. During the cutting process, ablation is performed on each tissue slice by laser to form at least three marking points, and the first coordinates of each marking point are recorded;

[0084] S3: Acquisition of slice images of tissue slices with marked points;

[0085] S4: Acquire second coordinates of each marking point in the slice image, compare the second coordinates with the first coordinates, and locate the slice image based on the comparison result.

[0086] In some embodiments, the laser is a femtosecond laser.

[0087] In one or more embodiments, the depth of laser ablation, i.e., the length in the direction perpendicular to the cross section, is an integer multiple of the thickness of the tissue slice to be cut, thereby improving the efficiency of marking. In some preferred embodiments, the depth of laser ablation is equal to the thickness of the tissue slice to be cut, thus ensuring that the marking point on each tissue slice can be located within the tissue contour.

[0088] In one or more embodiments, the marking points can be randomly ablated on the cross section of the paraffin block, and after the laser ablates a marking point each time, the first coordinates of the formed marking points are recorded. In some preferred embodiments, the first coordinates of the required marking points on the same tissue section can also be calculated first, and then the laser is moved to the first coordinate position to ablate the marking points.

[0089] In some preferred embodiments, in order to correct each slice image using an affine transformation matrix, the marking points on the tissue slice are not collinear. In some embodiments, at least three marking points do not form three vertices of an isosceles triangle to avoid the situation where the slice image cannot be positioned by comparing the first coordinate and the second coordinate.

[0090] In one or more embodiments, the first coordinates of the marking points on different tissue slices may be the same or different. In one or more embodiments, the number of marking points on different tissue slices may be the same or different. In some preferred embodiments, the number of marking points on the tissue slice is 3 to 6. In some preferred embodiments, each marking point is close to the center of the tissue slice.

[0091] In some preferred embodiments, in step S2, before cutting the paraffin block each time, a cross-sectional image of the cross section of the to-be-cut portion of the paraffin block is collected, a tissue contour line is extracted from the cross-sectional image, a first coordinate is determined within the tissue contour line, a laser is ablated at the first coordinate to form a marking point, and the to-be-cut portion is cut to obtain a tissue slice with the marking point. In some embodiments, a first-order edge detection operator such as Roberts Cross operator, Prewitt operator, Sobel operator, Kirsch operator, compass operator, etc. can be used to identify tissue contour lines; a second-order edge detection operator such as Canny operator, Laplacian operator, etc. can also be used to identify tissue contour lines. Preferably, the Canny operator or the Sobel operator is used to identify tissue contour lines in the cross-sectional image.

[0092] In some preferred embodiments, in step S2, the method of determining the first coordinates includes the following steps: obtaining the centroid of the tissue contour, determining the first coordinates for forming the marking points around the centroid, and the geometric center of the polygon formed by the lines connecting the first coordinates is located near the centroid. In this embodiment, by setting the geometric center of the polygon formed by each marking point near the centroid of the tissue contour, each marking point can be evenly distributed on the tissue slice, avoiding serious local damage to the tissue slice caused by the concentration of marking points.

[0093] Embodiment 2:

[0094] Based on Example 1, in step S2, the method of determining the first coordinate includes the following steps:

[0095] For a first tissue slice, a first centroid of a first tissue contour line is obtained, and first coordinates for forming a marking point are determined around the first centroid, wherein the geometric center of a polygon formed by connecting lines of the first coordinates coincides with the first centroid;

[0096] For other subsequent tissue slices, the first coordinates of each marking point of the adjacent previous tissue slice are obtained, and after each first coordinate is moved in the same direction by the same distance, it is determined whether all the first coordinates after the movement are located within the second tissue contour line of the current tissue slice;

[0097] If yes, the first coordinates after the movement are used as the first coordinates of the current tissue slice;

[0098] If not, the second centroid of the second tissue contour is obtained, the geometric center of the polygon is moved to coincide with the second centroid, the polygon is rotated, and the coordinates of each vertex of the polygon are used as the first coordinates of the current tissue slice.

[0099] In this embodiment, the first coordinates on the next tissue slice are selected based on the first coordinates on the previous tissue slice, ensuring that the first coordinates on two adjacent tissue slices do not overlap, which can effectively reduce the probability of laser ablation of the cancerous area of ​​the tissue slice.

[0100] In one or more embodiments, the moving distance of each first coordinate may be greater than the diameter of the cancerous area. For example, if the diameter of the cancerous area is 10 μm, the moving distance of the first coordinate is set to be greater than 10 μm, thereby avoiding the cancerous area by moving the first coordinate.

[0101] In some preferred embodiments, in two adjacent tissue slices, if the first coordinates of the previous tissue slice are all located within the second tissue contour after moving along the first direction, the first coordinates of the next tissue slice continue to move along the first direction. In some preferred embodiments, after the geometric center of the polygon is moved back to the centroid of the tissue contour, the subsequent first coordinates preferably move along the second direction, which is different from the first direction.

[0102] Embodiment 3:

[0103] In order to better illustrate the method for determining the first coordinates of two adjacent tissue slices in Example 2, this embodiment exemplarily provides steps for determining the first coordinates of the first to fourth tissue slices.

[0104] like Figure 2 As shown in (a), the first tissue contour of the first tissue slice is obtained, and the first centroid O1 of the first tissue contour is calculated. The first coordinates of three marking points A1, B1 and C1 are randomly selected in the first tissue contour, and the geometric center of the triangle formed by the three marking points A1, B1 and C1 coincides with the first centroid O1.

[0105] like Figure 2 As shown in (b), the first coordinates of the three marking points A1, B1 and C1 are obtained, and the first coordinates of A1, B1 and C1 are moved upward by a distance D. The three marking points A2, B2 and C2 obtained are all located within the tissue contour line of the second tissue slice. Therefore, the first coordinates of the three marking points A2, B2 and C2 are used as the first coordinates of the second tissue slice.

[0106] like Figure 2As shown in (c), the first coordinates of the three marking points A2, B2 and C2 are obtained, and the first coordinates of A2, B2 and C2 are moved upward by a distance D to obtain three marking points A3', B3' and C3'. Among them, the marking point B3' is located outside the tissue contour line of the third tissue slice. The second tissue contour line of the third tissue slice is obtained, and its second center of mass O2 is calculated based on the second tissue contour line. The geometric center of the triangle formed by the three marking points A3', B3' and C3' is overlapped with the second center of mass O2, and the triangle is rotated 180°. The coordinates of the three vertices A3, B3 and C3 of the rotated triangle are used as the first coordinates of the third tissue slice.

[0107] like Figure 2 As shown in (d), the first coordinates of the three marking points A3, B3 and C3 are obtained, and the first coordinates of A3, B3 and C3 are moved downward by a distance D. The three marking points A4, B4 and C4 obtained are all located within the tissue contour line of the fourth tissue slice. Therefore, the first coordinates of the three marking points A4, B4 and C4 are used as the first coordinates of the fourth tissue slice.

[0108] In this way, the first coordinates of all tissue slices are determined.

[0109] Those skilled in the art should understand that the moving direction and moving distance of the first coordinate can be arbitrary. Preferably, the moving distance of the first coordinate can be greater than the diameter of the cancerous area to better avoid the cancerous area.

[0110] Embodiment 4:

[0111] Based on the above embodiment, in step S2, before cutting the tissue slice, a film is attached to the tissue slice.

[0112] In some embodiments, a thin film may be attached to the tissue slice first, and then the marking point may be ablated by laser. In one or more embodiments, a laser may be used to ablate the marking point on the tissue slice first, and then a thin film may be attached to the tissue slice.

[0113] In one or more embodiments, the film may be a PEEK film.

[0114] Embodiment 5:

[0115] On the basis of the above embodiment, in step S4, an affine transformation matrix corresponding to the slice image is obtained based on the first coordinate and the second coordinate, the slice image is corrected using the affine transformation matrix, the third coordinate of each marking point in the corrected slice image is obtained, the third coordinate is compared with the first coordinate, and the corrected slice image is positioned based on the comparison result.

[0116] After identifying the second coordinates of each marked point on the slice image, the affine transformation matrix corresponding to the slice image is obtained based on the second coordinates and the first coordinates. The calculation formula of the affine transformation matrix is:

[0117]

[0118] In the formula, x and y are the first coordinates (x, y), x' and y' are the second coordinates (x', y'), and among the six variables of the affine transformation matrix, s x and y are variables that control scaling and flipping along the X and Y axes, respectively. x and α y are the variables that control the rotation along the X-axis and Y-axis, respectively. x and t y are variables that control translation along the X and Y axes respectively.

[0119] Based on the first and second coordinates of the marker points on the tissue slice, the six variables in the affine transformation matrix can be obtained by solving the six-variable linear equation. For example, the first coordinates of the three marker points formed on the tissue slice are (x1, y1), (x2, y2), (x3, y3), and the second coordinates of the three marker points extracted on the slice image are (x′1, y′1), (x′2, y′2), (x′3, y′3). Then, according to the calculation formula of the affine transformation matrix, 6 equations can be obtained:

[0120] x′1=s x x1+α x y1+t x

[0121] y′1=α y x1+s y y1+t y

[0122] x′2=s x ·x2+α x y2+t x

[0123] y′2=α y ·x2+s y y2+t y

[0124] x′3=s x ·x3+α x y3+t x

[0125] y′3=α y ·x3+s y y3+t y

[0126] By solving the six equations simultaneously, we can get the variables in the affine transformation matrix, and apply the affine transformation matrix to each pixel on the slice image to realize the correction of the slice image.

[0127] like Figure 3 As shown in (a), the laser ablates the end surface of the paraffin block to obtain three marking points A, B, and C. When the tissue section is cut from the paraffin block, it deforms and the three marking points all show different degrees of displacement, such as Figure 3 (b) is shown. By solving the affine transformation matrix, the slice image corrected by the affine transformation matrix is ​​shown as Figure 3 As shown in (c), the three marking points A, B, and C have returned to their positions before cutting.

[0128] Embodiment 6:

[0129] On the basis of the above embodiment, if there are at least four marking points on the slice image, the polygonal area formed by the at least four marking points is divided into at least two triangular areas, and the affine transformation matrix of each triangular area is obtained; for the pixel points located within the triangular area on the slice image, the affine transformation matrix corresponding to the triangular area is used to process the pixel points; for the pixel points located outside the triangular area on the slice image, the affine transformation matrix corresponding to the triangular area closest to the pixel points is used to process the pixel points.

[0130] In some preferred embodiments, the polygonal area is divided into multiple groups of triangular areas using different division methods, an affine transformation matrix group for each group of triangular areas is obtained, the slice image is corrected using the affine transformation matrix group, the corrected tissue contour line on the corrected slice image is obtained, and the affine transformation matrix group is selected based on the corrected tissue contour line.

[0131] Take a quadrilateral region as an example, Figure 4As shown in (a), the line connecting the marker point A and the marker point C divides the quadrilateral area into two triangular areas ABC and ADC. The first affine transformation matrix is ​​obtained based on the first and second coordinates of the three marker points A, B, and C of the triangular area ABC. The second affine transformation matrix is ​​obtained based on the first and second coordinates of the three marker points A, D, and C of the triangular area ADC. The slice image is processed using the first and second affine transformation matrices. Specifically, the first affine transformation matrix is ​​used to correct the pixels in the triangular area ABC, and the second affine transformation matrix is ​​used to correct the pixels in the triangular area ADC. For the pixel points on the slice image that are located outside the triangular area ABC or the triangular area ADC, the distance between the pixel point and the two triangular areas is determined, and the affine transformation matrix of the triangular area that is closer is used to correct the pixel point. After the correction is completed, the first corrected slice image is obtained, and the tissue contour line of the first corrected slice image is extracted.

[0132] like Figure 4 As shown in (b), the line connecting the marker point B and the marker point D divides the quadrilateral area into two triangular areas ABD and BCD. The third affine transformation matrix is ​​obtained based on the first and second coordinates of the three marker points A, B, and D of the triangular area ABD. The fourth affine transformation matrix is ​​obtained based on the first and second coordinates of the three marker points B, C, and D of the triangular area BCD. The slice image is processed using the third and fourth affine transformation matrices. Specifically, the third affine transformation matrix is ​​used to correct the pixels in the triangular area ABD, and the fourth affine transformation matrix is ​​used to correct the pixels in the triangular area BCD. For the pixel points on the slice image that are located outside the triangular area ABD or the triangular area BCD, the distance between the pixel point and the two triangular areas is determined, and the affine transformation matrix of the triangular area that is closer is used to correct the pixel point. After the correction is completed, a second corrected slice image is obtained, and the tissue contour line of the second corrected slice image is extracted.

[0133] The tissue contour lines of the first and second corrected slice images are compared with the tissue contour line of the cross-sectional image, and a corrected image whose shape of the corrected tissue contour line is closer to the tissue contour line of the cross-sectional image is used as the corrected slice image.

[0134] Embodiment 7:

[0135] Based on the above embodiment, a positioning system for pathological slice images includes:

[0136] A laser, used for emitting laser light to form at least three marking points on the tissue slice to be cut of the paraffin block, and recording the first coordinates of each marking point;

[0137] A microtome, used to cut tissue sections with marked points from paraffin blocks;

[0138] Pathology scanners for acquiring slice images of tissue sections with marker points;

[0139] The image processing unit obtains the second coordinates of each marking point in the slice image, compares the second coordinates with the first coordinates, and locates the slice image based on the comparison result.

[0140] Embodiment 8:

[0141] Based on the above embodiments, Figures 5 to 7 As shown, a positioning system for pathological slice images of tissues includes a transmission mechanism for driving a film 8 to move. On the moving path of the film 8, there are arranged a stage 1 for placing a paraffin block 2, a blade 3 of a slicer for cutting the paraffin block 2, a film sticking mechanism 4 located just above the paraffin block 2, and a laser 16 arranged on the film sticking mechanism 4.

[0142] When in use, the film 8 is coated with an adhesive, such as formaldehyde gelatin solution or polylysine solution. When the film 8 moves to the top of the paraffin block 2, the film 8 stops moving. The film sticking mechanism 4 moves downward to stick the film 8 to the surface of the paraffin block 2. The laser 16 emits laser to ablate the marking point on the paraffin block 2. The blade 3 cuts the tissue slice with the marking point from the paraffin block 2, and the cut tissue slice adheres to the film 8 and moves with the film 8 to the subsequent processing process. By analogy, the cutting and movement of all tissue slices are completed.

[0143] In some preferred embodiments, Figure 5 and Figure 6 As shown, the conveying mechanism includes a reel 7 wound with a film 8, and a driving device for pulling the film 8 out of the reel 7. In one or more embodiments, a first roller 6 and a second roller 5 independently driven by a motor are further provided on the moving path of the film 8. In one or more embodiments, a third roller 9 and a fourth roller 10 driven by a motor are further provided between the first roller 6 and the second roller 5 and are located on both sides of the film laminating mechanism 4.

[0144] In some preferred embodiments, Figure 7 As shown, the film sticking mechanism 4 includes a moving platform 18 that can move in the vertical direction, a transverse linear guide pair 14 is arranged on the lower surface of the moving platform 18, a longitudinal linear guide pair 15 is slidably arranged on the transverse linear guide pair 14, and a laser 16 is slidably arranged on the longitudinal linear guide pair 15. Before the ablation mark point, according to the determined first coordinate, the sliders of the transverse and longitudinal linear guide pairs are driven to move, and the laser 16 is moved to the specified position.

[0145] In some preferred embodiments, Figure 7As shown, the lower surface of the moving platform 18 is hingedly connected to a connecting rod 11 through a bearing 17, and a torsion spring is provided at the hinge connection. The connecting rod 11 is rotatably connected to a film sticking wheel 12. In one or more embodiments, the lower surface of the moving platform 18 is hingedly connected to two film sticking wheels 12. In the initial state, as shown in FIG. Figure 5 As shown, the two film sticking wheels 12 are located directly above the paraffin block 2, and under the action of the torsion spring, the two film sticking wheels 12 abut against each other. During the downward movement of the film sticking mechanism 4, the film sticking wheels 12 push the film 8 to move toward the paraffin block, and after contacting the paraffin block, as shown in FIG. Figure 6 As shown, the film sticking mechanism 4 moves from the center of the paraffin block to both sides to the film sticking state, thereby exhausting the air between the film and the paraffin block. After the film sticking is completed, the film sticking mechanism 4 is reset upward, and the two film sticking wheels 12 are reset to the position in the initial state under the action of the torsion spring.

[0146] The terms "first", "second", etc. (e.g., first coordinate, second coordinate, first centroid, second centroid, etc.) used in the present invention are only used to distinguish the corresponding components for the sake of clarity of description, and are not intended to limit any order or emphasize importance, etc. In addition, the term "connected" used in the present invention may be directly connected or indirectly connected via other components unless otherwise specified.

[0147] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for positioning a tissue pathology section image, characterized in that: The following steps are involved: S1: Fix the tissue in paraffin to form a paraffin block; S2: cutting the paraffin block to obtain a plurality of tissue slices. During the cutting process, ablation is performed on each tissue slice by laser to form at least three marking points, and the first coordinates of each marking point are recorded; S3: Acquisition of slice images of tissue slices with marked points; S4: Acquire second coordinates of each marking point in the slice image, compare the second coordinates with the first coordinates, and locate the slice image based on the comparison result.

2. A method for positioning a tissue pathology section image according to claim 1, characterized in that: In step S2, before cutting the paraffin block each time, a cross-sectional image of the cross section of the to-be-cut portion of the paraffin block is collected, a tissue contour line is extracted from the cross-sectional image, a first coordinate is determined within the tissue contour line, a laser is ablated at the first coordinate to form a marking point, and the to-be-cut portion is cut to obtain a tissue slice with the marking point.

3. A method for positioning a tissue pathology section image according to claim 2, characterized in that: In step S2, the method of determining the first coordinate includes the following steps: The centroid of the tissue contour is obtained, and first coordinates for forming a marking point are determined around the centroid, and the geometric center of a polygon formed by connecting lines of the first coordinates is located near the centroid.

4. The method for positioning a tissue pathology section image according to claim 2, characterized in that: In step S2, the method of determining the first coordinate includes the following steps: For a first tissue slice, a first centroid of a first tissue contour line is obtained, and first coordinates for forming a marking point are determined around the first centroid, wherein the geometric center of a polygon formed by connecting lines of the first coordinates coincides with the first centroid; For other subsequent tissue slices, the first coordinates of each marking point of the adjacent previous tissue slice are obtained, and after each first coordinate is moved in the same direction by the same distance, it is determined whether all the first coordinates after the movement are located within the second tissue contour line of the current tissue slice; If yes, the first coordinates after the movement are used as the first coordinates of the current tissue slice; If not, the second centroid of the second tissue contour is obtained, the geometric center of the polygon is moved to coincide with the second centroid, the polygon is rotated, and the coordinates of each vertex of the polygon are used as the first coordinates of the current tissue slice.

5. The method for positioning a tissue pathology section image according to claim 4, characterized in that: In two adjacent tissue slices, if the first coordinates of the previous tissue slice are all located within the second tissue contour line after moving along the first direction, the first coordinates of the next tissue slice continue to move along the first direction.

6. The method for positioning a tissue pathology section image according to claim 1, characterized in that: In the step S2, before cutting the tissue slice, a film is attached to the tissue slice.

7. The method for positioning a tissue pathology section image according to claim 1, characterized in that: In step S4, an affine transformation matrix corresponding to the slice image is obtained based on the first coordinate and the second coordinate, the slice image is corrected using the affine transformation matrix, the third coordinate of each marking point in the corrected slice image is obtained, the third coordinate is compared with the first coordinate, and the corrected slice image is positioned based on the comparison result.

8. The method for positioning a tissue pathology section image according to claim 7, characterized in that: If there are at least four marking points on the slice image, divide the polygonal area formed by the at least four marking points into at least two triangular areas, and obtain an affine transformation matrix of each triangular area; For pixel points located within the triangular region on the slice image, the pixel points are processed using an affine transformation matrix corresponding to the triangular region; For a pixel point on the slice image that is outside the triangular region, the pixel point is processed using an affine transformation matrix corresponding to the triangular region that is closest to the pixel point.

9. A method for positioning a tissue pathology section image according to claim 8, characterized in that: The polygonal area is divided into multiple groups of triangular areas using different division methods, an affine transformation matrix group of each group of triangular areas is obtained, the slice image is corrected using the affine transformation matrix group, a corrected tissue contour line on the corrected slice image is obtained, and the affine transformation matrix group is selected based on the corrected tissue contour line.

10. A positioning system for tissue pathology slice images, characterized in that: include: A laser, used for emitting laser light to form at least three marking points on the tissue slice to be cut of the paraffin block, and recording the first coordinates of each marking point; A microtome, used to cut tissue sections with marked points from paraffin blocks; Pathology scanners for acquiring slice images of tissue sections with marker points; The image processing unit obtains the second coordinates of each marking point in the slice image, compares the second coordinates with the first coordinates, and locates the slice image based on the comparison result.

Images