Calculation of dose equivalent for positrons using the monte carlo code egs5

Medical staff face the risk of chronic exposure to the annihilation photons generated by the positrons emitted from the radiopharmaceutical 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) while administering it to patients for positron emission tomography (PET). In order to assess doses for this exposure, an EGS5 user code, UCF18DOSE, was developed to calculate the dose equivalent rates for positron. The energy spectra of positrons and photons used in the dose calculations were confirmed by the good agreement between the calculated pulse height distribution for a ¹⁸F point source and measurements recorded on scintillation counters. The dose rates calculated for a ¹⁸F-FDG line source were compared with those measured by a personal dosemeter at tissue depths of 70 μm and 1 cm. There is qualitative agreement between those results.