VISUALISATION AND QUANTIFICATION OF LUNG CONTENT OF RADIONUCLIDES ASSOCIATED WITH NUCLEAR AND RADIOLOGICAL EMERGENCIES.

In a situation when radionuclides accidentally or deliberately are dispersed in the environment, there is a need for rapid investigation of the internal contamination in exposed individuals. In this work, the possibilities of visualising and quantifying uptakes of different radionuclides in the lung region of an adult individual using gamma camera systems have been examined, mainly on a two-headed stationary clinical gamma camera. An anthropomorphic phantom was used to mimic acute lung uptakes in three different body sizes. The gamma camera was calibrated with the lung inserts filled with a homogeneous solution of (99)Tc(m), (46)Sc and (32)P, or with point sources of (241)Am, (57)Co, (85)Sr, (137)Cs and (90)Sr/(90)Y. It was found that for the stationary gamma camera the minimum detectable activity in the lungs using a 5-min acquisition time ranged from 0.53 kBq for (46)Sc to 50 kBq for (32)P. Furthermore, the point sources of (137)Cs, (60)Co and (90)Sr/(90)Y (0.16, 0.80 and 2.2 MBq, respectively) located in the lung insert of the phantom, could be clearly visualised, exhibiting distinct intensity maxima. It is thus concluded that gamma camera systems can be useful for rapid assessment of acute intakes of radionuclides associated with emergency preparedness, both in terms of localisation and quantification.