If a person has come into contact with or ingested radioactive materials that are still emitting alpha, beta, or gamma radiation, they may have radiation traces on them. A Geiger counter cannot identify ex-post exposure to radioactive material if the subject has been in contact with it but does not contain any active particles on or in it. It is strongly recommended to use a dosimeter when accessing premises with an ionizing radiation background that exceeds the norms.
The dosimeter “counts” the effect of radiation during the period of stay in an area of increased risk. The dosimeter cannot identify exposure ex-post if it was not worn throughout the exposure period. If you have any concerns about radiation exposure that has not been properly monitored, it is highly recommended that you consult with a qualified medical professional.