Radiation doses by therapeutical practices with iodine 131

The aim of this document is to estimate the doses to workers and public due to therapeutical practices with iodine 131. Environmental and personal doses by external irradiation were determined using thermoluminescent dosimeters (TLD). The environmental dosimetry resulted in an equivalent dose H*(10) of approximately 0,1 mSv. The calculated personal equivalent dose Hp (10) was of the order of 0,1 mSv. The exposition rate was measured, being the values obtained in the range of 0,20 and 0,35 mSv/h. (1m from the abdominal wall). Concentrations of iodine 131 were determinate in the air of the room, during the first day in the hospital. Values obtained were between 0,04 Bq/l and 0,20 Bq/l. Surface samples were taken in the service, obtaining levels of contamination in the range of 0,001 and 0,4 Bq/cm2. The surface samples obtained in the hospital room were about 0,15 Bq/cm2. Urine samples were collected resulting in an eliminated activity of iodine 131, during the first 24 hours, of about 60 % of the administered activity. Samples of sweat of different cutaneous regions were obtained, the maximum values of the activity measured reached 200 Bq/cm2. According to the obtained results it is important to elaborate guides to be given to patients as an instrument to reduce the external exposure and to avoid internal contamination. (author)