Local motion compensation based on list mode data

A medical imaging system that corrects motion in a reconstructed image with data used to reconstruct the image, comprising:

• a plurality of detectors that detect electron-positron annihilation events;
• a coincident detector that identifies pairs of substantially simultaneous coincident events within the electron-positron annihilation events;
• a line of response processor that processes the events and identifies lines of responses that connect events within each coincident event pair;
• and
• one or more processors programmed to:
• estimate a characteristic feature for the region of interest from the lines of response,
• motion-correct the lines of response corresponding to the region of interest, and
• reconstruct a motion corrected image corresponding to the region of interest from the motion corrected lines of response.

A computer implemented program for performing the steps of:

• generating a plurality of intermediate regions of interest images from an motion-blurred region of interest for a number of short time frames;
• adjusting, for each of the plurality of intermediate regions of interest images, a voxel value for one or more voxels that reside inside a region of interest and that intersect a corresponding line of response;
• computing a center of mass for each of the intermediate regions of interest images;
• combining the individual center of masses to compute an aggregate center of mass for a full time range of an acquisition;
• computing a difference between each center of mass and the aggregated center of mass;
• computing a motion correction translation vector based on the differences;
• correcting data corresponding to the region of interest for motion by shifting lines of response in the data by an amount given by the motion correction translation vector;
• and
• reconstructing a motion-corrected image corresponding to the region of interest with the corrected data.

A computer implemented program for performing the steps of:

• computing a vector that represents a center point of a shortest line segment connecting a pair of lines of response;
• computing the temporal motion of the center of mass from a distribution of center points in the region of interest;
• correcting the data for motion by shifting lines of response in the original data to the overall center of mass;
• and
• reconstructing a motion-corrected image corresponding to the region of interest with the corrected data.

A method for locally correcting motion in an image, comprising:

• localizing a region of interest within an uncorrected image;
• correcting the localized region of interest for motion based on a characteristic feature of the localized region of interest;
• and
• forming a corrected image by replacing the localized uncorrected region of interest with the localized corrected region of interest.