HITS TO BONE CELL-NUCLEI FROM NONUNIFORM RADIOACTIVE LABELS

The stochastic aspects of alpha-particle traversals through nuclei of bone-lining cells from nonuniform radioactive labels are worked out. B oth the residence time of the target and the hit rate are considered r andom variables. It is shown that with any type of bone remodeling the fraction of cells not hit increases with increasing nonuniformity of the label concentration. Thus, a completely uniform concentration repr esents the most dangerous situation. A possible negative correlation b etween residence times and hit rates, observed in some experiments, te nds to decrease the probability of alpha-particle hits. As a practical application, the theory is applied to the International Commission on Radiological Protection model of the distribution of Pu-239 in the hu man body. In the case of 50 years of chronic ingestion of 1 annual lim it of intake (ALI) per year for class W and chronic inhalation of 1 AL I/year for class Y compounds, more than 19.4 and 8.5% of the nuclei of bone-lining cells are traversed by at least one alpha-particle, respe ctively.