Exposure of medical personnel to radiation during radionuclide therapy practices

Abstract

Radioisotopes that emit beta radiation are used for the treatment of hepatocellular carcinoma, of arthritic patients (radiosynovectomy) and treatment of bone metastases with, respectively, I-labelled lipiodol, colloidal citrate of Y or and Sm-labelled EDTMP. Radiation energy of these radioisotopes that emit beta or beta and gamma radiation (from 300 to 2000 keV) leads to an increase in radiation dose received by nuclear medicine staff. In this paper we focused on clinical and laboratory staff exposure during these types of metabolic radiation therapies. Cylindrical LiF thermoluminescence dosimeters were used to measure radiation-related whole-body doses (WBDs) and finger doses of the clinical staff. Exposure of the two radiopharmacists and three nurses taking part in I-labelled lipiodol, Y-colloid and Sm-EDTMP therapies, for 12 months in succession, were 146 microSv and 750 microSv, respectively, considering WBD, and 14.6 mSv and 6.5 mSv, respectively, considering finger doses. Extrapolated annual exposures (six radiosynovectomies per year) for the rheumatologists were estimated to be 21 microSv (WBD) and 13.2 mSv (finger dose). Extrapolated annual WBDs and finger doses (25 I-labelled lipiodol treatments per year) for radiologists were estimated to 165 microSv and 3.8 microSv, respectively. Fortunately, these doses were always lower than the limits reported in the European Directive EURATOM 96/29 05/13/1996 (WBD <20 mSv.year; finger dose: 500 mSv.year) but have to be added to those relative to other metabolic radiotherapies such as radioiodine treatments and new metabolic radiotherapies (Y-conjugated peptides or antibodies). Nevertheless, the global exposure of medical staff involved in all these clinical practices justifies dosimetry studies to validate protocols and radiation protection devices for each institution.