Patent ID: 7564035

Claim:
A method of generating detector efficiency data for a positron emission tomography scanner including: a detector array for generating detection data; and a single photon source, a coincidence detection system for producing coincidence count data (M ij ) in the detection data during an acquisition when a positron source is inside the scanner, and wherein the scanner is arranged to produce artificial coincidence count data (M′ ij ) during an acquisition using the single photon source; wherein the method comprises the steps of: conducting an acquisition procedure using the single photon source to produce detection data; generating artificial coincidence count data taking the position of the single photon source into account; and processing said detection data using an efficiency estimation algorithm to calculate data representative of the efficiencies of individual detectors in said array by processing said artificial coincidence count data, wherein the efficiency estimation algorithm is based upon a measurement model which is additive, in that the measured model is related to a weighted sum of individual efficiencies.