Skin contamination by radiopharmaceuticals and decontamination strategies

The aim of the present study was to evaluate the percutaneous penetration of five common radiopharmaceuticals ((99m)Tc, (67)Ga, (125)I, (111)In and (51)Cr) and to evaluate the effect of decontamination by a detergent solution dedicated to hospital institutions for that purpose. The skin kinetic profiles were established by using the in vitro Franz cell method over 24h. The skin distribution in each skin layer was quantified after 6h exposure time and the efficacy of the detergent solution to remove radionuclides was evaluated also after 6h. The most striking result was the repartition into two classes of kinetic profiles: (125)I and (99m)Tc permeated quickly (∼60% of applied activity after 24h) while the 3 other radionuclides permeated slowly (from ∼2.75% for (67)Ga to ∼10% of applied activity for (111)In). The lag times, i.e. the time necessary to cross the skin varied from 20min for (99m)Tc to 5h for (51)Cr, which accumulated in skin compartments. Skin washings with the detergent solution were particularly efficient for this radionuclide, contrary to the others for which the washing procedure should be applied earlier. The permeation of ions was dependent on their chemical and physical forms and on their salting-in or salting-out effects (coordination state and Hofmeister series).