Method of evaluating the resolution of a volumetric imaging system and image phantom used during the resolution evaluation
AssigneeVolumetrics Medical Corp.
InventorMichael M. Thornton
Life of this patent
Estimating the term…
Abstract
A method for evaluating the spatial resolution of a volumetric medical imaging system comprises imaging an image phantom including a sphere surrounded by a uniform medium. The image phantom is imaged and the resulting volumetric data set is used to generate an edge response function in three dimensions. Differentiating the edge response function produces a plane spread function. The method simultaneously measures the spatial resolution in all directions, providing a bulk measurement resolution. Alternatively, the edge response function may be assembled in a manner so as to independently measure the axial and trans-axial resolution of the volumetric imaging system.
Claims29
A method of evaluating axial and trans-axial resolution of a scanner of a volumetric imaging system, comprising:
- placing an image phantom comprising a high contrast sphere in a uniform medium within a field of view of said scanner;
- scanning the image phantom using the scanner and generating resultant volumetric image data (voxels);
- identifying a first conic region having a vertex generally coincident with the sphere centroid, said first conic region being centered about a positive axis of the scanning geometry of the scanner and identifying a second conic region having a vertex generally coincident with the sphere centroid, said second conic region being centered about a negative axis of the scanning geometry;
- processing voxels within the first and second conic regions to assemble surface spread curves in positive and negative axial directions;
- processing voxels outside of the first and second conic regions to assemble surface spread curves in positive and negative trans-axial directions;
- and
- processing the surface spread curves in the positive and negative axial and trans-axial directions to yield a modulation transfer function representing the axial and trans-axial resolution of said scanner.
A method of evaluating axial and trans-axial resolution of a scanner of a volumetric imaging system, comprising:
- placing an image phantom comprising a high contrast sphere in a uniform medium within the field of view of said scanner;
- scanning the image phantom using the scanner and generating resultant volumetric image data (voxels);
- identifying a first conic region having a vertex generally coincident with the sphere centroid, said first conic region being centered about a positive axis of the scanning geometry of the scanner and identifying a second conic region having a vertex generally coincident with the sphere centroid, said second conic region being centered about a negative axis of the scanning geometry;
- processing voxels within the first and second conic regions to assemble surface spread curves in positive and negative axial directions;
- identifying a third conic region having a vertex generally coincident with the sphere centroid, said third conic region being centered about the positive axis of the scanning geometry of the scanner and identifying a fourth conic region having a vertex generally coincident with the sphere centroid, said fourth conic region being centered about a negative axis of the scanning geometry, said third and fourth conic regions encompassing greater volumes than said first and second conic regions;
- processing voxels outside of the third and fourth conic regions to assemble surface spread curves in positive and negative trans-axial directions;
- and
- processing the surface spread curves in the positive and negative axial and trans-axial directions to yield a modulation transfer function representing the axial and trans-axial resolution of said scanner.
Dependencies are inferred from the claim text.