Apparatus and method for photogrammetric surgical localization
First Claim
1. Apparatus for defining the location of a medical instrument relative to features of a medical workspace including a patient'"'"'s body region, comprising:
- workspace imaging means positionable for producing a plurality of pairs of images of a medical workspace, each of said image pairs comprising two images made along one of each of a different one of two sightlines, said sightlines intersecting at an angle;
digitizing means operably disposed for digitizing each of said images of said image pairs to produce sets of image signals, one said set of image signals corresponding to each of said images;
fiducial means removably positionable in said workspace for providing a series of fiducial points held in fixed spatial relation to one another; and
computing means connected to said digitizing means to receive said image signals therefrom, and including memory means for storing pattern recognition data and instrument structure data correlated to each of a plurality of different medical instruments, said computing means being operable to;
establish a workspace coordinate framework in three dimensions from one of said pairs of images made when said fiducial structure is positioned within said workspace, determine workspace coordinates in said workspace framework of any selected point which can be identified from both images of said pair, recognize one of said medical instruments when it is visible in both images of one of said pairs, and compute workspace coordinates of an operative portion of said recognized instrument.
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Abstract
A method and apparatus for defining the location of a medical instrument relative to features of a medical workspace including a patient'"'"'s body region are described. Pairs of two-dimensional images are obtained, preferably by means of two video cameras making images of the workspace along different sightlines which intersect. A fiducial structure is positioned in the workspace for defining a three dimensional coordinate framework, and a calibration image pair is made. The calibration image pair comprises two 2D projections from different locations of the fiducial structure. After the calibration image pair is made, the fiducial structure is removed. A standard projection algorithm is used to reconstruct the 3D framework of the fiducial structure from the calibration image pair. Appropriate image pairs can then be used to locate and track any other feature such as a medical instrument, in the workspace, so long as the cameras remain fixed in their positions relative to the workspace. The computations are desirably performed with a computer workstation including computer graphics capability, image processing capability, and providing a real-time display of the workspace as imaged by the video cameras. Also, the 3D framework of the workspace can be aligned with the 3D framework of any selected volume scan, such as MRI, CT, or PET, so that the instrument can be localized and guided to a chosen feature. No guidance arc or other apparatus need be affixed to the patient to accomplish the tracking and guiding operations.
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Citations
16 Claims
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1. Apparatus for defining the location of a medical instrument relative to features of a medical workspace including a patient'"'"'s body region, comprising:
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workspace imaging means positionable for producing a plurality of pairs of images of a medical workspace, each of said image pairs comprising two images made along one of each of a different one of two sightlines, said sightlines intersecting at an angle;
digitizing means operably disposed for digitizing each of said images of said image pairs to produce sets of image signals, one said set of image signals corresponding to each of said images;
fiducial means removably positionable in said workspace for providing a series of fiducial points held in fixed spatial relation to one another; and
computing means connected to said digitizing means to receive said image signals therefrom, and including memory means for storing pattern recognition data and instrument structure data correlated to each of a plurality of different medical instruments, said computing means being operable to;
establish a workspace coordinate framework in three dimensions from one of said pairs of images made when said fiducial structure is positioned within said workspace, determine workspace coordinates in said workspace framework of any selected point which can be identified from both images of said pair, recognize one of said medical instruments when it is visible in both images of one of said pairs, and compute workspace coordinates of an operative portion of said recognized instrument. - View Dependent Claims (2, 3, 4, 5, 10, 11, 12, 13, 14)
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6. Apparatus for defining the location of a medical instrument relative to features of a medical workspace including a patient'"'"'s body region, comprising:
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workspace imaging means positionable for producing a plurality of pairs of images of a medical workspace, each of said image pairs comprising two images made along one of each of a different one of two sightlines, said sightlines intersecting at an angle;
digitizing means operably disposed for digitizing each of said images of said image pairs to produce sets of image signals, one said set of image signals corresponding to each of said members of said image pairs;
fiducial means removably positionable in said workspace for providing a series of fiducial points held in fixed spatial relation to one another; and
computing means connected to said digitizing means to receive said image signals therefrom, and including memory means for storing pattern recognition data and instrument structure data correlated to each of a plurality of different medical instruments, said computing means being operable to;
establish a workspace coordinate framework in three dimensions from one of said pairs of images made when said fiducial structure is positioned within said workspace, determine workspace coordinates in said workspace framework of any selected point which can be identified from both images of said image pair, correlate scan coordinates for each of three or more selected scan markers with the workspace coordinates of the same said scan markers as derived from one of said image pairs, compute conversion functions for converting the scan coordinates of any selected feature in a scan made in a scan coordinate framework to workspace coordinates in said workspace framework, and for converting the workspace coordinates of any selected feature observable in both images of said image pairs to scan coordinates in said scan coordinate framework, recognize one of said medical instruments when it is visible in both of said images, and compute workspace coordinates of an operative portion of said recognized instrument. - View Dependent Claims (7, 8, 9)
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15. A fiducial structure for establishing a three-dimensional coordinate framework from a photographic image pair, comprising:
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a sufficient number of fiducial indicators arranged to a three-dimensional coordinate system; and
frame means for supporting and connecting said fiducial indicators, said frame means consisting of a frame constructed to hold said fiducial indicators in fixed relation to each other. - View Dependent Claims (16)
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Specification