Possibilities of the exposure reduction of hands during the preparation and application of radiopharmaceuticals.

BACKGROUND: The current routinely used methods of estimating the skin equivalent dose relies on the finger dosimetry which usually largely underestimates the real maximum exposure and thus appropriate correction factors have to be used.

METHODS: The group under the investigation consisted of 10 workers preparing and 5 workers administering radiopharmaceuticals labelled with 18F. The monitoring was carried out using 12 pairs of thermoluminiscent dosimeters (TLDs) placed on each hand of the worker. A total of 46 measurements were completed. The maximum exposure of the skin of hands, defined in terms of the quantity of the personal dose equivalent Hp(0.07), was related to the unit activity of radiopharmaceutical with which the worker came into the contact during the measurement.

RESULTS: The exposure of the hands of workers handling 18F-labelled radiopharmaceuticals showed significant inhomogeneity. Out of 15 workers, in 53 % of cases, the maximum skin exposure was observed on the tip of their index finger. It was estimated that in about 60 % of the cases (during the preparation and administration of radiopharmaceuticals), the exposure may exceed the 3/10 of the annual dose limit. Moreover, in 40 % of all cases, the exposure may even be higher than this dose limit. The established relevant correction factors reached the values up to 8 (as for preparations) and 13 (as for administrations).

CONCLUSIONS: The study resulted in the establishment of the appropriate correction factors and in the recommendations of procedures aimed at the further reduction of the exposure of extremities (Tab. 3, Fig. 2, Ref. 17).