[en] The information on environmental gamma radiation given in the last report (Spiers, 1956) was limited by the small amount of experimental data then available. Considerably more information has been accumulated since then and a summary has been published in the Report of the United Nations Scientific Committee on te Effects of Atomic Radiation 1958). The data reported from Austria, France, Sweden and the U.S.A. show that in general dose-rates out-of-doors range from about 0 mrads per year over sedimentary rocks to about 200 mrads per year in granite districts. In houses a similar range of doserates is indicated, the rates in individual houses depending upon the nature of the building materials. In some parts of the world, however, very much higher dose-rates have been observed. On the extensive area of monazite sand in the Kerala State of India dose-rates of up to 4000 mrads per year have been recorded and the mean dose-rate for 10 villages with a total population of 52,000 has been estimated to be 1270 mrads per year. Mean dose-rates of 500 and 1600 mrads per year have also been reported from two localities in Brazil

[en] This brief note discusses Roentgen's measurements of x-ray transmission in platinum, lead, zinc and aluminium (1895) and suggests that some part of the x-ray spectrum used by Roentgen lay above the platinum K absorption edge, thus offering an explanation of his finding the platinum absorption to be greater than that of lead. (U.K.)

[en] The human body, together with its haemopoietic tissues, may be irradiated by various types of ionizing radiation arising from sources external to the body or from internally deposited radioactive substances. The biological effects of ionizing radiations depend in part upon their physical characteristics. Charged particles, such as α- and β-particles, protons and cosmic-ray mesons, ionize a medium directly, whereas X-rays, γ-rays and neutrons interact by producing secondary charged particles that ionize the medium in which they are released

[en] This brief historical review of the development of radioprotective recommendations in the field of medicine makes particular reference to the work of British Hospital Physicists, and spans the period from the work of Professor Sidney Russ in 1915 to the development of the NRPB and ICRP, with particular reference to development in concepts over the last decade, including the definition of a risk-weighted whole body dose, and to the occupational levels achieved in the U.K. (U.K.)

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[en] In the nuclear industry comparatively small occupational doses have been accumulated over periods of up to 30 yr. These doses are not large and their mean doses can be of the same order as, or less than, those received from background and medical diagnostic radiation. Under these circumstances, it is clear that all relevant radiation-occupational, background and medical-must be taken into account in any estimation of radiation risk at low dose levels. This has not been done in the recent analyses of cancer deaths among the Hanford workers. In this paper, the effect of errors in the doses from background, medical and occupational exposure are evaluated and the limitation imposed by background radiation on the value of doubling dose is considered. (author)

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[en] Consideration is given to the problems and advantages associated with the use of the basic and derived units of the International System of Units (SI) in radiology and radiation protection. These units have already been adopted in science generally, and in laboratory medicine in particular, and the transition to the application of SI units in radiology and radiation protection will make these fields consistent with the whole of the rest of science. Not all the problems associated with the transition to the new units in laboratory medicine have been entirely solved, and experience here may well be relevant to the field of radiology. The SI unit of absorbed dose is the gray, 1 J kg^-1, and of activity is 1 nuclear transformation per second. The gray is also the name of the SI units of specific energy imparted, kerma, absorbed dose and absorbed dose index. The numerical factors required for the transition to the SI units are discussed, and the problems associated with the change-over considered. There will be ultimate gains in both consistency and convenience when the new system is established and familiar. There is still considerable debate on SI units for exposure and dose equivalent. A sound theoretical basis for a system of quantities and units in radiology was formulated by ICRU (International Commission on Radiation Units and Measurements, Radiation Quantities and Units, Washington, D.C., ICRU Report No.19, Part I (1971)). (U.K.)