In vivo monitoring of occupationally exposed individuals to 18FDG in CRCN/NE

Abstract

The increasing demand for PET radiopharmaceuticals in Brazil results in increasing of the number ofoccupationally exposed individuals (OEI) to the radiopharmaceutical 18F in the form of 18FDG, increasingthereby the risk of accidental incorporation. This work aims to implement an in vivo internal monitoringtechnique applied to 18FDG radiopharmaceutical at the Divisão de Produção de Radiofármacos (DIPRA)of the Centro Regional de Ciências Nucleares do Nordeste (CRCN/NE). The detection system used was aNaI(Tl) 3”x3” detector connected to a compact electronic module operated by the Genie 2000 software. Itwas calibrated using a brain phantom containing a standard source of 22Na which simulates acontaminated individual. Based on the calibration factor it was possible to determine the minimumdetectable activity (MDA) of the detection system and then, through use of biokinetic models provided bythe ICRP in its publication 53 and edited by the AIDE version 6.0 software, it was possible to calculatethe minimum detectable effective dose (MDED) which is an indication of the technique sensitivity. TheMDED was estimated for the in vivo measurements performed up to 0.1 day after the occurrence of anintake by ingestion. The value obtained was compared to the Recording level of 1 mSv recommended bythe IAEA. After validation of the in vivo monitoring technique, a serie of measurements were performedon a group of occupationally exposed workers from DIPRA shortly after completion of production andquality control of 18FDG radiopharmaceutical procedures. It is concluded that the proposed technique issufficiently sensitive for its application in internal occupational monitoring.