Patent ID: 7397038

Claim:
A method of positron emission tomographic nuclear medical imaging, comprising the steps of: detecting a plurality of gamma interactions in a first gamma ray detector, wherein said plurality of gamma interactions corresponds to a single coincidence event; for each of said plurality of detected gamma interactions, determining the depth of interaction in said gamma ray detector and the amount of energy deposited in said gamma ray detector; determining which one of said plurality of detected gamma interactions in said gamma ray detector occurred first, by 1) selecting an arbitrary one of said plurality of detected gamma interactions as a tentative first interaction; 2) selecting a remaining one of said plurality of detected gamma interactions as a tentative second interaction; 3) calculating a hypothetical Compton scatter angle between said tentative first and second interactions based on the determined amount of energy deposited thereby in said gamma ray detector; 4) comparing said hypothetical Compton scatter angle with an actual Compton scatter angle as obtained from said determined depth of interaction of said tentative first and second interactions; 5) determining whether said tentative first and second interactions are actual first and second interactions based on the result of said comparison; 6) if the determination of step 5) is negative and additional remaining detected gamma interactions exist, repeating steps 2) through 5) for a different remaining one of said plurality of detected gamma interactions; 7) if the determination of step 5) is negative and no additional remaining detected gamma interactions exist, repeating steps 1) through 6) for a different arbitrary one of said plurality of detected gamma interactions; and generating a line of interaction between a determined actual first interaction in said first gamma ray detector and a similarly determined actual first interaction in a second gamma ray detector, to thereby determine the location of said coincidence event.