Generic models for radionuclide dosimetry: 11C-, 18F- or 75Se-labelled amino acids

A generic biokinetic model was developed for use in the assessment of the internal dose received by human subjects injected with amino acids labelled with 11C (T1/2=0.34 h, β+, γ), 18F(T1/2=1.83 h, β+, γ) or 75Se (T1/2=119.8 d, β−, γ). This generic model was used in conjunction with the MIRDOSE 3 computer programme to calculate radiation doses to adults; these radiation doses were compared with those calculated using compound-specific models for two [11C]-, and eight [18F]-labelled amino acids and [75Se]selenomethionine. In general, the effective doses, as well as the organ and tissue doses, calculated using the generic model agreed within a factor of 2 or less, with those calculated using compound-specific models; the generic model tended to over-, rather than under-estimate the organ and tissue doses. It was concluded that for 11C- and 18F-labelled amino acids and for 75Se-labelled amino acids or their analogues, the single generic biokinetic model could be applied for general radiation protection purposes.