Graph Four shows the number of microcuries of fission products ingested at times after detonation to produce 1.0 rad to the thyroid. III. 89 Doses to the Bones The three principal bone-seeking isotopes of concern are sr? - yy, Sr“, and Ba 140 -Ia 140 . Eveluation of these may be made in terms of amount deposited in the bones versus maximum permissible body burdens, or in rads of dosethat they deliver after deposition. Since values for maximum per- missible body burdens are based on the concept that these will be maintained indefinitely in the body, they are not so valid for & 89 and BaltO_ tal? when considering short periods of emergency intake. The following principal assumptions are used in calculating the doses to the bones of adults: a. The percentages of the isotopes of gr7?_y%, er, and Ba 140_,,tH40 in mixed fission products are according to Hunter and Ballau.? b. The percentages of intake of these isotopes that are deposited in the bones, the energies of emissions, and their effective half lives are according to reference five - except for sr90 where a@ 27.7 year radiological half life is used here. c. The mass of the bones is 7,000 grams. DOE ARCHIVES The method of calculation of doses to the bones is illustrated by computing the dose from Sr 89 from the intake of 27 microcuries (See IV Dis- cussion below) of mixed fission products on the 120th hour. 1401,140 culations were made for sr70_y90 and Ba Similar cal- and then the three doses 4