The effect of hexacyanoferrate(II) preparations, KFe[Fe(CN)6], (KFeHCF) anol Fe4[Fe(CN)6]3, (FeHCF) on intestinal radiocaesium absorption was studied in two male volunteers. The 134Cs absorption was decreased from 100 to 3-10% when 500-1000 mg KFeHCF or FeHCF were administered 10 min before the 134Cs-labelled test meal. However, when HCF was administered simultaneously with the test meal, the 134Cs absorption was decreased to only 38-63%. The biological half-time of previously absorbed 134Cs was reduced from 106 (73) to 44 (46) days by daily administration of 3 times 0.5 g KFeHCF. The 134Cs dose conversion factors lie below the values recommended by IRCP 30, indicating that the IRCP model represents a cautious description of the Cs biokinetics in our study.
