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

OBJECTIVE: Nuclear medicine technologists are exposed daily to the risk of skin contamination with radiopharmaceuticals. This study deal with the different elements associated with skin contaminations.

METHODS: To assess the incidence, routes and contamination activities, a long-term on-site survey was organized using a measurement system built in-house, together with a protocol based on fast detection, localization and quantification. Dosimetry calculations were carried out using Monte Carlo simulations and combined with the efficacy of skin decontamination, which was studied both in the context of daily practice of nuclear medicine and in vitro using pig skin samples.

RESULTS: In 10 months 560 inspections were carried out. Local contamination was found on the fingers of nuclear medicine technologists in 40 cases, but the increasing awareness caused a significant reduction over time. The measured activities ranged from 211 Bq/cm2 to 460 kBq/cm2, resulting in cumulated skin doses between 0.02 and 809 mSv. The poor efficacy of the decontamination during daily practice is supported by the in-vitro results. The course of a contamination is characterized by an effective first decontamination, followed by relatively ineffective steps. The efficacy of dedicated decontamination agents is indicated in only a few cases.

CONCLUSION: Skin contamination can be found in large doses on the skin among nuclear medicine technologists. Single contaminations can result in local skin doses exceeding the yearly dose limit because of the contribution of electrons at shallow depths and should therefore be prevented at any time. The use of a neutral hand soap should generally be preferred during decontamination. A general simplified method is proposed to assess the skin dose after a contamination with 99mTc-labelled radiopharmaceuticals or 18F-fluorodeoxyglucose.