Abstract: Estimation of radon exposure dose is a main component of internal radiation dose assessment, in which the dose conversion factor (DCF) serves as a key parameter. This study focuses on Taurus, the latest internal radiation software released by the UK Health Security Agency, and investigates and validates its application in calculating DCFs. First, by comparing the differences in calculating the deposition fractions of radon progeny in the respiratory system between Taurus and the previously widely used internal radiation software LUDEP and IMBA, it is found that the primary cause of these differences lies in the distinct respiratory tract models employed by each software. Second, Taurus is utilized to calculate DCFs for each of the five progeny of ²²²Rn and ²²⁰Rn under various conditions, such as different particle size distributions. The results indicate that the DCF for ²²⁰Rn progeny is approximately six times higher than that for ²²²Rn progeny, and the contribution of unattached radon progeny to the DCF is greater than that of attached radon progeny. Finally, Taurus is applied to calculate a series of DCFs in typical indoor and outdoor environments. The results, which show a high consistency with the DCFs in the International Commission on Radiological Protection (ICRP) Publication 137, demonstrate that Taurus not only offers comprehensive functionality and a high degree of flexibility in selecting input parameters but is also aligned with the latest ICRP database in terms of respiratory tract models, gastrointestinal tract models, and related biokinetic parameters.

Key words: radon exposure, dose conversion factor, dosimetric model, Taurus software, typical environmental conditions