FAT-CELLS IN RED BONE-MARROW OF HUMAN RIB - THEIR SIZE AND SPATIAL-DISTRIBUTION WITH RESPECT TO THE RADON-DERIVED DOSE TO THE HEMATOPOIETIC-TISSUE

Samples of human rib were collected at autopsy and 20 were selected fo r marrow fat cell measurement, representing an age range of 16-96 year s. The mean diameter of fat cells in red bone marrow of human rib was found to increase from around 48 mu m at ages 16-29 years to around 65 mu m at ages 82-96 years. There was a greater number of fat cells of smaller size range in younger ages compared with that in older ones. T he maximum size of fat cells was found to be 102 mu m. Calculated rado n-derived doses to haemopoietic tissue ranged from 60 to 162 mu Sv y(- 1) at average UK exposures of 20 Bq m(-3). It was concluded that the b one marrow fat fraction is the important parameter as far as alpha-rad iation dose from radon in fat is concerned. This updates the theoretic al estimates of dose carried out by Richardson et al. (1991).