US 9,959,683 B2 · Method of determining the position of an object using projections of markers or struts

Abstract

A 3-D model of a body part is created by using an object comprising markers, fixation members, and struts. The method involves first and second roentgenograms of the body part and the object disposed between an x-ray source and an x-ray imager. It then determines first and second sets of distances between projections of the markers or the struts, and determines first and second 3-D positions of the x-ray source and of the object with respect to the x-ray imager using predetermined distances between the markers or struts and the first and second sets of distances between their projections. The method then aligns the first and second 3-D object projections in a 3-D reference frame using the 3-D positions of the markers or struts with respect to the x-ray imager in the two orientations. The method creates the 3-D model of the object based on the 3-D object projections.

A method of creating a 3-D model of a body part, the body part being coupled to an object, the object comprising a plurality of markers at predetermined distances along the object, the method comprising:

receiving a first roentgenogram of the body part and the object disposed between an x-ray source and an x-ray imager in a first orientation, wherein the first roentgenogram includes an image of:
the body part,
the object, and
the plurality of markers;
receiving a second roentgenogram of the body part and the object disposed between the x-ray source and the x-ray imager in a second orientation, wherein the second roentgenogram includes an image of:
the body part,
the object, and
the plurality of markers;
determining a first set of projections of the plurality of markers on the first roentgenogram;
determining a first 3-D position of the x-ray source and a first 3-D position of the object with respect to the x-ray imager in the first orientation by satisfying following mathematical equations:
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wherein (x,y,z) are coordinates of the x-ray source, (x0,y0,z0) through (x3,y3,z3) are coordinates of the plurality of markers, (X0,Y0,Z0) through (X3,Y3,Z3) are coordinates of the first set of projections of the plurality of markers on the first roentgenogram, and l01, l02, l03, l04, l12, l13, l14, l23, l24, l34 are the predetermined distances between the plurality of markers to determine the distances between the plurality of markers, distances between the first set of the projections of the plurality of markers on the first roentgenogram and the plurality of markers, and distances between the plurality of markers and the x-ray source;
determining a second set of projections of the plurality of markers on the second roentgenogram;
determining a second 3-D position of the x-ray source and a second 3-D position of the object with respect to the x-ray imager in the second orientation by satisfying following mathematical equations:
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=
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wherein ('x,'y,'z) are coordinates of the x-ray source, (x0,y0,z0) through (x3,y3,z3) are coordinates of the plurality of markers, (′X0,′Y0,′Z0) through (′X3,′Y3,′Z3) are coordinates of the second set of projections of the plurality of markers on the second roentgenogram, and l01, l02, l03, l04, l12, l13, l14, l23, l24, l34 are the predetermined distances between the plurality of markers to determine the distances between the plurality of markers, and distances between the second set of projections of the plurality of markers on the second roentgenogram and the x-ray source, and distances between the second set of projections of the plurality of markers on the second roentgenogram and the plurality of markers;
aligning the first and second 3-D object projections in a 3-D reference frame using the 3-D positions of the plurality of markers with respect to the x-ray imager in the first and second orientations;
and
creating a 3-D model of the imaged body part in the 3-D reference frame based on the first and second 3-D object projections.

1,321 more elements

Method of determining the position of an object using projections of markers or struts

Life of this patent

Method of determining the position of an object using projections of markers or struts

Life of this patent

Abstract

Claims28