Physics

POSITRON DECAY (β + = e + )Proton rich unstable radionuclides withTransition Energy >1.02 MeV can generate two β particles:One β − (to combine p + => n o ) and One β + (to be emitted), [2 x 0.511 MeV]p + (+ β − + β + ) => n o + β + + ν, ZDaughter = (ZParent –1)18F => 18 O + β + + ν (+E of β + => range of β + < 5mm )9 8(ν : neutrino: no charge, negligible mass, spin)but soon there follows:ANNIHILATION: β + (+ e - ) => 2 x 511 keV photons at 180 0(Imaging: Coincidence Detection, PET)