Interactive explainer
From Physics to Image
Step through how a PET image is made — from a single positron to the fused clinical picture.
1 · Positron emission & annihilation
A proton-rich radionuclide (e.g. ¹⁸F) emits a positron (β⁺). After a short path it meets an electron and annihilates, converting mass to energy as two 511 keV photons travelling ~180° apart.
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