Memoranda from the British Committee on Radiation Units and Measurements. 1. Use of air kerma for photon dosimetry in air.

Abstract

1. Use of air kerma for photon dosimetry in airPublished Online:28 Jan 2014https://doi.org/10.1259/0007-1285-55-653-375SectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail AboutAbstractExposure, expressed in terms of its unit the röntgen, has been widely used for the dosimetry of photons since its introduction for X radiation in 1928 and its extension to γ radiation in 1937.Although in recent years absorbed dose has to a large extent replaced exposure in clinical dosimetry, nevertheless exposure has continued to be used in deriving absorbed dose and for measurements in air generally. When in 1953 the value of 100 ergs per gram was adopted by ICRU as the value of the unit of absorbed dose, the rad, one of the reasons was so that the numerical value of an exposure expressed in röntgens would be fairly close to the numerical value of the absorbed dose to water resulting from that exposure (assuming that electron equilibrium existed at the point of measurement). Once however a change is made to SI units, i.e. the coulomb per kilogram (=3876 röntgens) for exposure, and the gray (=1 joule per kilogram =100 rad) for absorbed dose, this approximate agreement between the numerical values of the two quantities no longer exists.In view of the change to SI units and the widespread use of absorbed dose in radiotherapy, BCRU recently recommended a revised procedure for the calibration of dosemeters for use in radiotherapy where the measurement takes place in an appropriate phantom (BCRU, 1980). The main intention was to provide the user with a calibration in terms of the quantity required, namely absorbed dose to water. Previous article Next article FiguresReferencesRelatedDetailsCited byInstructions to authors29 May 2014 | The British Journal of Radiology, Vol. 68, No. 805Instructions to authors29 May 2014 | The British Journal of Radiology, Vol. 66, No. 788Instructions to authors29 May 2014 | The British Journal of Radiology, Vol. 66, No. 781Instructions to authors29 May 2014 | The British Journal of Radiology, Vol. 65, No. 769Instructions to authors29 May 2014 | The British Journal of Radiology, Vol. 64, No. 757Realisation of the ISO Narrow Spectrum Series of filtered radiations at the National Physical Laboratory19 December 2000 | Journal of Radiological Protection, Vol. 8, No. 4When did you last see your röntgen?-the SI units and their use6 December 2000 | Physics in Medicine and Biology, Vol. 29, No. 2SI units of exposure in radiologyC. K. Bomford and S. B. Sherriff28 January 2014 | The British Journal of Radiology, Vol. 56, No. 667The hazards of acupunctureC. E. Latter28 January 2014 | The British Journal of Radiology, Vol. 56, No. 667 Volume 55, Issue 653May 1982Pages: 321-B24 © The British Institute of Radiology History Published onlineJanuary 28,2014 Metrics Download PDF