Imaging for Physicists

Prompt Events (II)  Scattered events

● One or both photons detected have undergone a Compton interaction

● Loss in energy and change in direction ● Due to poor energy resolution, many scattered photons cannot be discriminated ● Wrong LOR assigned  Multiple (triple) events ● Three events from two annihilations detected ● Event is disregarded ● Proportional to count rate

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ESTRO Teaching Course Advanced Imaging: PET – Basic Principles