/ TABLE V TO PLUTONIUM BY INHALATION ESTIMATED ACCUMULATED AVERAGE ORGAN DOSES FOR PERSONS EXPOSED The Time since Exposure mal Estimated Exposure (years) (MPL) as the is odel rtain veror as Accumulated Average Organ Dese® Bone (rads) Liver (rads) Lung (rads) 80 24 1.4 6.7 37 24 1.4 6.7 37 80 24 1.6 7.6 42 90 24 1.8 8.6 47 100 ah 2.0 9.6 53 110 2.3 11.0 61 130 24 2.5 12.0 66 140 24 3.3 16.0 87 190 oh gham 11 , 24 3.4 16.0 90 190 24 3.6 17.0 95 200 23 1.1 5.0 28 63 23 1.1 5.0 28 63 4-hese values are being brought up-to-date using the latest values for the body burden. This is a subject of a future report. ter bone maximum permissible level (MPL) = 0.04 UCi. sige oy hort RN negRS ONgr IEARNToteae ing these studies has been carried out at the Univer- 1 sity of Utah Medical School. 2 on 10te Luce ites age ther ,oOne These observations have the first group of 6 beagles were injected (IV) with verse biological effects (e.g., practical threshold) below certain levels of injected plutonium. Injected doses ranged from 0.016 to This 2.9 pCi per kg hody weight for 6 groups of about point has not been accepted by everyone and has not 12 dogs each. been proven unequivocally for alpha-emitting tadio- The first animal to die in July 1956 of an osteogenic sarcoma was in the highest dose In 1961, an osteosarcoma occurred in a beagle at the then lowest dose (0.016 uCi per kg), and since then several lower dose groups have been added to the experiment. jJels injected is reduced. prompted numerous investigators to predict no ad- 239 Pu citrate. group. ver, On December 1, 1952, The lowest dose group, 0.00064 pCi per kg, corresponds roughly to the max- nuclides .?4 C. Determination of Piutonium in the Body by In Vivo Measurements 1, Plutonium in the Chest Cavity. During the most recent (late 197l-early 1972) medical examina- imum permissible occupational body burden (0.04 pCi) tions at Los Alamos, estimates were made of the in man. amount of plutonium in the lung and respiratory To date, the 0.016 pCi per kg dose level is of interest, as 4 dogs have developed osteosarcomas, giving a tumor incidence of 33 percent. The aver- lymph nodes of each subject using an tm vivo lung counter (see Appendix D). Figure 9 shows the pair of detectors in position for counting the low-energy age time from injection to death for these animals X-rays emerging from the chest. was 9.9 years, and the average skeletal dose from were made of the liver region in several subjects injection to death was estimated to be about and of the hands of persons known to have had skin 80 rads)? (a more recent estimate suggests about wounds contaminated by plutonium. 50 rads), tectable activity (MDA) for human subjects measured We do not know whether osteosarcomas will Measurements also The minimum de- be produced at dose levels lower than 0.016 uci/kg with the LASL detectors varies with several param- and can only await the outcome of this important eters such as body build and chest thickness. experiment. average MDA for a 2000-second counting time is about However, we do know that the tumor incidence decreases and the time required for tumors to develop increases as the amount of piutonium An 7 nCi if ome uses the 95 percent confidence level. For the 68 percent confidence level and a similar