The effect of isotope on the dosimetry of inhaled plutonium oxide

Results of experimental studies in which animals inhaled 238PuO2 or 239PuO2 aerosols have shown that the biokinetics and associated radiation dose patterns for these two isotopes differ significantly due to differences in in-vivo solubility caused by the 260-fold difference in specific activity between 238PuO2 and 239PuO2. We have adapted a biokinetics and dosimetry model derived from results of the ITRI dog studies to humans and have calculated dose commitments and annual limits on intake (ALI) for both Pu isotopes. Our results show that the ALI calculated in this study is one-third that for class Y 238Pu from ICRP 30, and one-half or equal to that for class Y 239Pu, depending on how activity in the thoracic lymph nodes is treated dosimetrically. (author)