ae ed than 607 of the RaD, the dose rate te the skeleton is,abaut 10 times trabecular and cortical samples are not uniformly distributed between that to the other parts of the bocy. the two sexes, the average for each respective type of bone is higher in men than in women. Finally, the problem of the RaF-RaD equilib rivm in the skeleton was considered, sampling procedures, these results do indicate the RaD concentration This is important beceise the dose is essenti ally due to the alpha-emitting RaF. While there are many questions involved in the is higher in trabecular than in cortical bone and is higher in men than The results were obtained by analyzing the in women. naP within a few weeks after Surgery and then again efter several months. On a regional basis, there is no apparent correlation in the Table 4 (Slide 5) shows the RaF to RaD ratio to oe 1.0 + 6.2 end thus the metabolic properties are essentially control led by those of ReD, measured copulation as’ show: in Table 6 (Slide 6). that is, on the average, there is littie excess or deficiency of RaF of measurements on rib specimens from 14 people who lived in Chicago 15 over RaD. years or more, The concentrations reage over a factor of 6, but average O.177 pe/g ash, vnich is slightly higher than the overall average of Fig. 2 (Slide 6) is a plot cf the RaD vs. the pae26 concentrations in 1238 samples from about 100 individuals. This is a series 0.146 pe/g ech but it There is littie correlation is about the same as the average trabecular bone. and in a given pa@6 interval of 0.01 pe/e ash, the RaD concentrations The pa-“° values average 0.015 pe/g ash, which is about that expected may vance over a factor of 6. in Chicago residents, (22) The RaD joes appear to increase with pae?o We have also tried to determine the source of ReD in the body ( mcentration ard all points, except two, lie above the line: and, &5 shown in Table 7 (Slide 9) six sources are considered: raat (Rab) = 0.56 (raé25y' +72 226 and no? in the boey, RaD in potable water, RaD in the atmospnere, 222 short lived Rn 2 Gaughters in the air and RaD in food, where the pareatheses refer to the concentration in units of pc/g ash of the enclosed species. Ra The significance of this dine is unknown, Using the exponential model for excretion and the parameters The two points below the curve are less Slgificeny than the others because Tor leed aid Rad metabolism in the "Standard man? (9s12;15) based on taey are data trom specimens cbtained from chi):irer and there 1: some those given in the Report ef the International Commissicn of Radiation Protection, we have estimated the contr.isutions of these various sources evidence that children have lower RaD concentrat:01s than do adults. (9) The overail average of RaD was 0.146 + 0.020 pe/g esh and of pa@*6 to the body content, 0.037 + 0.007 pe/g ash. significant, but the values used is extremely digh, 220 Rn bone samples to average 3.13 pe/g ash, about 75% greater than that in about 10 times value of 3. pe/l is also (14) high. The We conclude, therefore, that in most individuals the only significant sources of RaD to the body are The average RaD concentration in men, 0.16 ve/g¢ ash, Was 35% higher than the 0.119 peg ash in women. (9) the average, and cons2quently, few people would be exposed to this. rable 5 .Slije 7) shows the RaD concentration in the trabecular cortical bone sample:, The contribution of drinking water appears _ food and air, While the The general agreement of the calculated with the measured vaiues 1s significant, although, because of the assumptions in the -h- > , = “NAME ptrvistadudalen . te CN ne lal a Sel SONeet ey