British Journal of Radiology (2003) 76, 579
© 2003 British Institute of Radiology
doi:
Status of the dosimetry for the radiation effects research foundation (DS 86). By Committee on Dosimetry for the Radiation Effects Research Foundation, et al, pp. 212, 2001 (National Academy Press, Washington DC), £32.95 ISBN 0-309-07559-9
C J Martin
Assessment of the radiation doses received by the Atomic bomb survivors of Hiroshima and Nagasaki is of considerable importance because of its influence on the estimates of radiation risk from which radiological protection recommendations are derived. The dosimetry system 1986 (DS-86) contained the first comprehensive system of dose assessment for 100 000 survivors studied by the Radiation Effects Research Foundation. Questions have arisen about some features of DS-86 and whether it adequately describes the neutrons released by the Hiroshima bomb and this book discusses these uncertainties and summarizes the current state of knowledge.
The main component of the dose is from gamma rays and the two show reasonable agreement. However, measurements of thermal neutron activation in some materials have suggested that more fast neutrons were present when the Hiroshima bomb was dropped, particularly at distances greater than 1500 m from the hypocentre. There was no such discrepancy for the bomb dropped in Nagasaki. Re-assessment based on modified source models and taking account of differences in other factors such as the terrain have not been able to come up with a reason for the discrepancy.
There are other factors that lend weight to the implication that the current source model may be incorrect, such as the significantly greater number of aberrant cells per Sievert of exposure among the Hiroshima survivors than the survivors of the Nagasaki bomb. If a neutron component was actually larger than has been estimated in Hiroshima, then a greater proportion of the affect on the survivors would be due to neutrons, which would reduce the current estimate of risk per Sievert.
This book describes the present status of DS-86, discusses the current state of knowledge about the uncertainties and recommends studies needed for possible future improvement.
