Doppler-broadening of positron annihilation in a biological environment.
The aim of this study was to investigate the Doppler effect of the 511 keV gamma peak from positron annihilation in biological matter. The broadening of the annihilation peak is due to positron annihilation with electrons that have high momentum. In aqueous solutions annihilation depends on the temperature and it is linked positronium formation. Measurements in vivo, on human brain, were taken during the diagnosis of positron emission tomography (PET) on healthy patients by injecting them with the beta emitter of short lifetime 18F. The Doppler-broadening in biological tissues rich in water content decreased significantly compared to biological solutions and water.
Torrisi
L
L
Department of Physics, University of Messina, Italy.
La Mela
C
C
Foti
G
G
D001834:Body Water / Q000737:chemistry; D001921:Brain / Q000000981:diagnostic imaging*; D004301:Doppler Effect; D004583:Electrons; D005462:Fluorine Radioisotopes; D015902:Gamma Cameras; D006801:Humans; D055585:Physical Phenomena; D010825:Physics; D012016:Reference Values; D013696:Temperature; D014055:Tomography, Emission-Computed / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D014867:Water / Q000737:chemistry
D005462:Fluorine Radioisotopes; D014867:Water