Characterization of 41Ar production in air at a PET cyclotron facility

Abstract

In the production of Positron Emission Tomography (PET) nuclides at a medical cyclotron facility [Formula: see text]Ar (T[Formula: see text] = 109.34 m) is produced by the activation of air due to the neutron flux, according to the [Formula: see text]Ar(n, [Formula: see text])[Formula: see text]Ar reaction. In this work, we describe a relatively inexpensive and readily reproducible methodology of air sampling that can be used for quantification of [Formula: see text]Ar during the routine production of PET nuclides. We report the results of an extensive measurement campaign in the cyclotron bunker and in the ducts of the ventilation system, before and after final filtering of the extracted air. Air Samples were analyzed using a gamma-ray spectrometry system equipped with HPGe detector, with proper correction of the efficiency calibration to account for the samples density. The results of measurement were then used to evaluate the Total Effective Dose (TED) to the population living in the surrounding areas, due to routine emissions in the operation of the cyclotron. The average [Formula: see text]Ar saturation yield per one liter of air emitted in the environment resulted to be (0.044 ± 0.007) Bq/([Formula: see text]A ⋅ dm3). The maximum value of TED for the critical group of the population, even considering an overestimated workload, was less than 0.19 [Formula: see text]Sv/year, well below the level of radiological relevance.