Validation of use of the low energies library in the GATE program: assessment of the effective mass attenuation coefficient

GATE (Geant4 Application for Emission Tomography) is a versatile tool kit for nuclear medicine simulations of SPECT and PET studies. GATE takes advantage of well-validated libraries of physics processes models, geometry description, tracking of particles through materials, response of detector and visualization tools offered by Geant4. One package available to simulate electromagnetic interactions is LEP (Low Energy Electromagnetic Processes). The purpose of this work was to evaluate the LEP package used by GATE 4 for nuclear medicine shielding simulations. Several simulations were made involving a mono directional and 140 keV monoenergetic point source beam, passing through barriers of variable thickness of water and lead. The results showed good agreement with the theoretical model, indicating that GATE 4 uses correctly the LEP package. (author)