Application of in vitro dissolution tests to different uranium compounds and comparison with in vivo data

The most recent ICRP respiratory tract dosimetry model (Publication 66) proposes default values for the absorption of radionuclides into blood, defined as Type F, M or S, but recommends whenever possible the use of specific absorption parameters obtained from in vitro or in vivo experiments. Although in vivo data are preferred, in vitro dissolution is generally easier to determine and can be considered to provide intermediate values between default and in vivo absorption parameters. This study had therefore three objectives. The first was to compare in vitro dissolution test systems developed at IPSN and LRRI. The second was to use both test systems with several uranium compounds present at different stages of the uranium nuclear fuel cycle. The third objective was to compare these in vitro data with those obtained from in vivo experiments performed on rats intratracheally instilled with the same uranium compounds. In vitro and in vivo data sets were then used to calculate and compare specific dose coefficients.