Analysis of Air Discharges from a PET Radiopharmaceuticals Production Center Based on a Cyclotron

Abstract

The control of air contamination in a Nuclear Medicine Center (NMC) provided with a cyclotron for the production of radiopharmaceuticals is based on an automatic systems for air sampling and measurements. An important control for the assessment of dose to the population is aimed at the measurement of air concentration of stack release and inside the cyclotron vault during irradiation. The frequency of sampling can be setup as continuous with respect to the stack effluent release and cyclic for other work environments. The gamma-ray spectrometric measurement are made on-line and for a short time by using a shielded Marinelli beaker filled with sampled air and a gamma detector. The use of this system allow us to have very numerous air concentration data and a software for the analysis is needed. In this work is presented the analysis of the main data recorded in “San Gaetano” NMC at Bagheria (Italy) and are highlighted some anomalous events that have been happened some years ago. An evaluation with a common Gaussian Plume air dispersion modelling code allow us to verify the no radiological significance of the stack effluent releases in terms of potential dose to population reference group, sited more than 100 m away from the plant. A proposal for optimization of procedures, with the provision of air compressing stations (ACS) for both hot cells and cyclotron vault releases besides a change in the position and height of the stack, is also described.