Tc activity concentrations in room air and resulting internal contamination of medical personnel during ventilation-perfusion lung scans.

This paper presents the results of measurements of Tc activity concentrations in indoor air in a nuclear medicine department and resulting estimated Tc intake by medical personnel. Tc air activity measurements were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow, Poland, during ventilation-perfusion SPECT lung scans. Technetium from the air was collected by means of a mobile aerosol sampler with a Petryanov filter operating at an average flow rate of 10 dm min. Measured activities ranged from 99 ± 11 to 6.1 ± 0.5 kBq m. The resulting daily average intake of Tc by medical staff was estimated to be 5.4 kBq, 4.4 kBq, 3.0 kBq and 2.5 kBq, respectively, for male technicians, female technicians, male nurses and female nurses. Corresponding annual effective doses were 1.6 µSv for technicians and 1 µSv for nurses. The highest equivalent dose values were determined for extrathoracic (ET) airways: 5 µSv and 10 µSv for nurses and technicians, respectively. It is concluded that estimated annual absorbed doses are over three orders of magnitude lower than the dose limit established in the Polish Atomic Law Act and in recommendations of the International Commission on Radiological Protection for medical staff.