In-room imaging and MR planning

Random coincidences

• For a given pair of detectors:

~ ×

×

,1

,2

t : coincidence timing window R single : Single-channel count rate

• Width of coincidence window impacts R random • R random

will increase quadratically with activity, while R true

increases linearly

• R random

/ R true

range from 0.2 (brain) to 1 (abdomen)