Fig. 1From: Recent developments in time-of-flight PETCompared to conventional PET, the estimated time-of-flight difference (Δ t) between the arrival times of photons on both detectors in TOF-PET allows localization (with a certain probability) of the point of annihilation on the line of response. In TOF-PET, the distance to the origin of scanner (Δ x) is proportional to the TOF difference via the relation: Δ t: \(\Delta x = \frac {c \Delta t}{2}\), where c is the speed of light. t 1 is the arrival time on the first detector, and t 2 is the arrival time on the second detectorBack to article page