System for selecting true coincidence events in positron emission tomography

A method of collecting coincidence data comprising:

• selecting coincident events detected within a Compton camera array in which a first γ-ray and second γ-ray surpass an energy threshold and in which the first γ-ray is Compton scattered and detected in a first detector and the second γ-ray is Compton scattered and detected in a second detector;
• reconstructing a first cone surface corresponding to possible incident angles for the first γ-ray;
• projecting the first reconstructed cone onto the second detector;
• determining, within an angular resolution and a position resolution of the Compton camera array, a first probability corresponding to an overlap of the reconstructed cone surface with the second detector;
• reconstructing a second cone surface corresponding to possible incident angles for the second γ-ray;
• projecting the second reconstructed cone onto the first detector;
• determining, within an angular resolution and a position resolution of the Compton camera array, a second probability corresponding to an overlap of the reconstructed cone surface with the second detector;
• retaining data corresponding to coincidence events having both first and second probabilities above an acceptance threshold.