Detector head position correction for hybrid SPECT/CT imaging apparatus
AssigneeSiemens Medical Solutions USA, Inc.
InventorsSharon Wang, Joseph Fang
Life of this patent
Estimating the term…
Abstract
A system and method provide for more accurate SPECT/CT image registration. CT data is utilized to establish a global spatial coordinate system of a common test phantom. The common test phantom is then used to obtain a set of point source nuclear images. Three-dimensional CT point source data is mapped to a two-dimensional image plane of corresponding point source data, to obtain a pair of intersecting projection cones that are used to obtain a set of detector head position correction parameters to correct detector head positioning in the CT coordinate system when obtaining SPECT projection images of the same object.
Claims20
A method for calibrating a medical imaging apparatus that is capable of acquiring medical images of a region using least two different imaging modalities, comprising the steps of:
- imaging a multiple point source test phantom using each of said at least two different modalities;
- calculating centroids of imaged point source data for each of said at least two different modalities;
- aligning a point source centroid of a first of said at least two different modalities with a corresponding point source centroid of a second of said at least two different modalities so as to obtain a pair of conical generators;
- determining a pair of lines on intersections of cones generated by said pair of conical generators having an angle therebetween corresponding to the angle between said cones;
- and
- adjusting an image plane of one of said at least two modalities by modifying a normal thereof to correspond to said angle.
A method for calibrating a hybrid medical imaging apparatus that is capable of acquiring medical images of a region using a two-dimensional imaging modality and a three-dimensional imaging modality, comprising the steps of:
- imaging a multiple point source test phantom in three-dimensional space using said three-dimensional modality, and imaging said multiple point source test phantom in multiple two-dimensional images using said two-dimensional modality;
- calculating centroids of imaged point source data for each of said three-dimensional and multiple two-dimensional images;
- aligning a point source centroid of said three-dimensional image with a corresponding point source centroid of one of said multiple two-dimensional images so as to obtain a pair of conical generators;
- determining a pair of lines on intersections of cones generated by said pair of conical generators having an angle therebetween corresponding to the angle between said cones;
- and
- adjusting the image plane of said two-dimensional image by modifying a normal thereof to correspond to said angle.
A test phantom structure for calibration of a hybrid medical imaging apparatus to co-register a nuclear medical image with a medical image of a different modality, both obtained with said hybrid medical imaging apparatus, comprising a structure supporting a plurality of point source isotopes at locations such that lines connecting any two pairs of said point source isotopes will be skewed with respect to each other.
A method of correcting a SPECT projection image of an object obtained by a nuclear medical imaging apparatus to provide for accurate registration of said SPECT projection image with a three-dimensional CT image of the same object, comprising the steps of:
- storing a set of detector head position correction parameters for each of a plurality of predetermined image view angles;
- retrieving detector head position correction parameters corresponding to a specific view angle of said SPECT projection image, with respect to said CT image;
- adjusting a position of a detector head of said nuclear medical imaging apparatus in accordance with retrieved detector head position correction parameters;
- calculating view angle-dependent linearity correction coefficients in accordance with a retrieved detector head position correction parameter;
- acquiring SPECT projection image counts from said object with said detector head positioned at said adjusted position;
- and
- framing resulting SPECT projection image data in accordance with said view angle-dependent linearity correction coefficients.
Dependencies are inferred from the claim text.