2017 Imaging for Physicists Coursebook

Prompt Events

 Single event ●

single photon is counted by detector (1-10%)

 True coincidence ●

event derives from single positron-electron annihilation ● both photons reach tomograph without interaction  Random coincidence ● two nuclei decay at approximately the same time ● random event count rate (R ab ) between two detectors a and b :

2  

2   N NN R b a

ab

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ESTRO Teaching Course Advanced Imaging: PET – Basic Principles