Skin contamination of nuclear medicine technologists: incidence, routes, dosimetry and decontamination.

Skin contamination with radiopharmaceuticals can occur during biomedical
research and daily nuclear medicine practice as a result of accidental spills, after
contact with bodily fluids of patients or by inattentively touching contaminated
materials. Skin dose assessment should be carried out by repeated quantification
to map the course of the contamination together with the use of appropriate
skin dose rate conversion factors. Contamination is generally characterised by
local spots on the palmar surface of the hand and complete decontamination
is difficult as a result of percutaneous absorption. This specific issue requires
special consideration as to the skin dose rate conversion factors as a measure for
the absorbed dose rate to the basal layer of the epidermis. In this work we used
Monte Carlo simulations to study the influence of the contamination area, the
epidermal thickness and the percutaneous absorption on the absorbed skin dose
rate conversion factors for a set of 39 medical radionuclides. The results show
that the absorbed dose to the basal layer of the epidermis can differ by up to
two orders of magnitude from the operational quantity Hp(0.07) when using an
appropriate epidermal thickness in combination with the effect of percutaneous
absorption.