RESUMEN
In case of accidental intake of radioactive material, the dose assessment requires information on the radionuclide distribution in the body. Measurements of retention or excretion are compared with model's predictions to estimate the intake. The reference models for internal dosimetry purposes are those proposed by ICRP and have been recently updated in the 'Occupational Intakes of Radionuclides (OIR)' series. This work focusses on the implementation of the new caesium model in a computer package, ICRP130Models (integrated in the toolbox BIOKMOD), together with new features aimed at estimating the intake and the dose from bioassay measurements. The software gives the best fitted intake and the committed effective dose, as well as the chi-squared test and the p-value as an indication of the goodness of the fit in the assessment process. The possibility to build the model as a function of a parameter allows the user to look for different options when fitting the bioassay measurements.