80 THE SHORTER-TERM BIOLOGICAL HAZARDS GF A FALLOUT FIELD acute lethality in mice and rabbits. 228-242 (1958). Rad. Res. 4, 19, D.C. Jowes, E. P. Avpen, and V. P. Bonn, Nelative Biological Effectiveness of 100 KVP and 250 KVP X-radiation, Rad. Res, 6, 484 (1956). 20. ©. L. Prosser, E. Parner, and M. N. Swirr, The clinical physiology of dogs exposed to single total-body doses of X-ray. Atomic Energy Commission Report MDDC 1272 (CH 3738) 28. F. Kutinarr, J. i. Moraax, and W. F, Cuamnens, Jr, The use of small animals in medical radiation hivlogy. NMRI, Research Report, Parts 1 and 2,°N MO06-012 04.43 (1952), 29. C.J. Roperts and A. H. Dan, X-ray depth dose Measurements in a phantom dog, Atomic Energy Commission Document, VR~241, 1953, 21, EP. Cronxrre and G. Brecuzr, The protective effect. of granulocytes in radiation injury. An- Fisuier, Sensitivity of abdomen of rat to Xradiation. Am. J. Physiol. 161, 323-330 (1950). 31. Handbook of Atomic Weapons for Medical Officers. Prepared by the Armed Forces Medical Policy 50/30 of total body X-radiation for dags. Air Force. Nav. Med. P-1330 (1951). 32. A. W. Quanrerson, G. V. Leroy, A. A. Lizpow, (1946). nals N.Y, Acad. Sci. 69, 815-833 (1955). 22, C. A. Guniser, The determination of the lethal dose T. Vet, Resch. 14, 284-286 (1953). Am. 23. R. D. Bocuse and F. W. Bisuoe, Studies on the effect of massive doses of X-radiation on mortality in laboratory animals. H. §. Blair, Biological Effects of External Radiation, KNES series VI~2, McGraw-Hill, (1954). 24, J. L. Touts, B. G. Lamson, and 8. G. Mapnen, Mortality in swine exposed to gamma radiation from an atomic 409-415 (1954). bomb source. Radiol. 62, 25, Operation Greenhouse, Scientific Directors Report, Annex 2.2, Document WT-18. Available through the Technical Information Service, Oak Ridge, Tenn. 26, J. H. Rust, B. F. Traum, J. L. Wirotna, C. 8. Simons, and C. L. Coman, Lethal dose studies with burros and swine exposed to whole body cobalt-60 ° irradiation. Radiol. 62, 569-574 (1954). 27. J. C. Porrern, The biological effect of Roentgen tays of long and short wave length on the totally irradiated rat. Radiol. 37, 724-725 (1941). DISCUSSION ON TOPIC II 30, V. P. Bonn, M. N. Swret, A.C. Acoma, and M,C, Gamma Energy Spectra and Geometry Factor Couneil for Departments of the Army, Navy and Dr. Cronxire. Thank you, Dr. Bond. Be- fore throwing this open for general discussion and comment, it was called to my attention earlier by one of the members here that Dr. E, C. Hammonn, N. L, Barrerr, J. D. Rosen- BAUM, and B, A. Scuneropr, Medical Effects of Atomic Bombs, McGraw-Hill, N. ¥. (1956). LaRiviere in his presentation of Dr. Mather’s 33. A. A. Lizsow, 8. Warren, and E. Decourser, Pathology of atomic bomb casualties, Am. J, paper stated that 105 gamma radiation from heptunium was not important. I don’t think Path, 25, 863-1027 (1949). 34, G. V. Lanor, Hematology of atomic bomb casualties. Arch. Int. Med. 88, 691-710 (1950). you meant that, because work done in your own laboratory showed it was quite important, Dr. LaRivrere. 1 am afraid he did say that in his paper. 35. L, H. Hemezeman, H. Lisco, and J. G. Horrman, The acute radiation ayndrome: a study of nine eases and a review of the problem. Med. 36, 279-510 (1952). Am. Int, Dr. Cronzrrs. Possibly you would take back to him that there is a little difference of 36. R. J. Hasr#ruice and L. D. Marinetut, Physical- opinion, predominantly from work done in the Division of Biology and Medicine at NRDL. dosimetry and clinical observations on four hu- man beings involved in an accidental critical assembly excursion. Proc. International Conference on the Peaceful Uses of Atomic Energy The following comments were later supplied by Dr. R. L. Mather: Unfortunately I could notbe present at the i1, 25-34, Geneva, 1955. 37. A. K. Gusrova and G. D. Batsocoiov, Two cases of acute radiation disease in man. Prov. of the International Conference on the Peaceful Uses of Atomic Energy, 12, 35-44, Geneva, 1955, meeting, and during the discussion exception was taken to my statement that the 105 kev quanta from Np** have relatively low penetration and biological effectiveness. The statement is true to the extent that the usual gamme radiation from radioactive sources is of higher energy than 105 kev and will penetrate farther into a given material, particularly those materials with a high atomic number which are usually employed for shielding purposes. The biological effective- hess per quantum of radiation is proportional to the average amount of ionization which it 4 produces in a small volume of air (roentgens) which when computed turns out to be closely proportional to the energy of the quantum for energies above 100 kev. In relation to the human body, however, a 105 kev quanta has a 10 percent chance of passing through the body,front to back, without experiencing any interaction (rather good penetration). Because of the very large proportion of 108 kev quanta in the typical fallout radiation 4 days post detonation this radiation may account for 20 to 50 percent of the gamma ray intensity (either energy flux or roentgen or biological effectiveness) as stated. Neither the hazard of this 105 kev radiation nor the fact that it can be controlled by relatively thin layers of dense materials should ba ignored. Dr. Cronkite. Dr. Borg, in your presentetion you were obviously discussing things that were exclusively in a free air situation, without buildings and so on around. I believe the intent of this svmposium was to eventually get downto some practical situations of what might happen to man. I wouldlike not to get into a dissertation on this, but for you to make some comment on the general situation that existed in Japan where there were large concrete buildings next to people. How does this influence the dose that might be expected from prompt. radiation? Dr. Bore. The answeris that I don’t. know exactly, but the problem has been brought up before and Jooked into in this regard. The calculations which I discussed were mado assuming the detector to be well up in the air, without even a ground interface nearby to interfere. Most of the measurements with which they were checked, however, were made close to the ground surface. There have been attempts made to reason throughtheeffectthe ground might have on a measurement made 81