Evaluation of Actinide Oxide Distribution within Rat Lungs after Inhalation Exposure: Preliminary Results using Solid Track Detector Autoradiography

Solid track detectors (CR-39) have been used to visualise actinide oxides distribution in rat lungs using thick samples. Animals were exposed to aerosols of 237 NpO 2 or MOX obtained during the grinding step of the MIMAS process. After MOX inhalation, autoradiographs were performed on 200 μm thick cryostat lung sections after drying. One month after exposure, the autoradiographs showed a homogeneous particle distribution within lung parenchyma. By contrast, a heterogeneous distribution was observed as soon as 3 months after inhalation. After inhalation of NpO 2 , lungs were embedded in paraffin and autoradiographs were performed on blocks. Particle distribution appeared heterogeneous from 450 to 800 days after inhalation exposure, and areas of high α track density could be clearly associated with some specific lung structures or lesions identified on the last stained thin section.