Assessment of internal contamination hazard and fast monitoring for workers involved in maintenance operations on PET cyclotrons.

With the ever-increasing number of cyclotron installations, and therefore of the maintenance personnel involved, the possibility of swift, 'yes or no' screening for internal contamination becomes a prized asset. The present work presents one such procedure, evolved from an approximate whole body counting technique in widespread use in emergency situations. A detailed analysis of possible pathways for contamination leads to pinpointing the nuclides of interest. Different calibration methods are applied, showing moderate variation among them. The minimum detectable activity of order 1000 Bq is determined. The method proves sensitive enough to exclude significant contamination, or to identify its presence instantly  'on site' to prompt further in-depth investigation.