Attenuation and scatter quantification in positron emission mammography.

Positron emission mammography (PEM) studies of high precision diagnostic quality require not only to quantify the fraction of the 511 keV annihilation photons that are attenuated and scattered in the breast, but also to implement correction methods for these effects. This work presents a Monte Carlo (MC) simulation of a PEM system to quantify a) attenuation and scattering effects and b) spatial resolution anisotropy as a function of both the position in the PEM's field of view (FOV) and the amount of attenuating material. For a 6 cm thick phantom and an energy window of [350,750] keV, the PEM simulation study predicts large contributions of scattered events (33%) and an important loss of true coincidences (58%) due to attenuation. The simulation results were compared with experimental data using sealed 22Na point sources showing differences lower than 5% at the center and up to 19% in the corners of the system FOV. [ABSTRACT FROM AUTHOR]