[The radiation dose to the foetus during isotope investigations of the mother].

The radiation dose to the foetus from the application of five different 99mTechnetium compounds during isotope investigation of the mother was investigated. After i-v injection of 100 muCi (3.7 MBq) of 99mTc-compounds into pregnant rats, these were sacrificed during the first, second and third week of pregnancy and radioactivity was determined in the foetuses and in the blood and organs of the mother. From these measurements the proportion of total body activity in individual organs and their specific activity was calculated. From this data the radiation burden to the rat foetuses from the various 99mTc compounds could be evaluated. Making use of phantom studies and the known biokinetic data of technetium compounds in man it was possible to calculate the radiation dose to the human foetus during isotope investigations of the mother.