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Reports and Activities of International Commission on Radiation units and Measurements ICRU Hans-Georg Menzel Chairman – ICRU Main Commission CERN (retired) Bethesda, 12 Oct. 2016 The definition of appropriate quantities, and their associated units, is a fundamental necessity for any scientific endeavour and for any practical applications of scientific knowledge. It all began in1895 ... W C Röntgen demonstrates his x rays in Würzburg on Geheimrat von Kölliker’s hand Early 20th century: Lack of knowledge about the risks of exposure to radiation numerous injuries First International Congress of Radiology, London 1925 The urgent need for an internationally recognized unit for radiation exposure in medicine led to the creation of the International X-Ray Unit Committee 1950 renamed: Int. Commission for Radiological Units and Measurements ( ICRU) 2nd Congress of Radiology, Stockholm 1928 The International X ray and Radium Protection Committee established 1950 named International Commission on Radiological Protection (ICRP) Mandate: provide guidance for practical radiation protection Chairman: Rolf Sievert Absorbed Dose Following its mandate by the Int. Congress of radiology, ICRU introduced in 1953: The absorbed dose, D, is the quotient of the mean energy imparted by ionizing radiation to matter of mass dm d D dm • • • Absorbed dose is a metrological sound quantity Primary standards exist for some materials the unit is J/kg; special name for the unit: gray ICRU Mission Statement: To develop and promulgate internationally accepted recommendations on radiation related quantities and units, terminology, measurement procedures, and reference data for the safe and efficient application of ionizing radiation to medical diagnosis and therapy, radiation science and technology, and radiation protection of individuals and populations. ICRU is member of the CCU: Consultative Committee for Units, which reports to the International Committee for Weights and Measures (CIPM) ICRU History & Leadership: • First International Congress of Radiology 1925: International X-ray Unit Committee • Stockholm 1928 Officially Recognized • Propose and Develop Unit for Medical Radiation Applications • Laurie Taylor 1953 – 1969 • H.O. Wyckoff 1969 – 1987 • A. Allisy 1987 – 1994 • A.W. Wambersie 1994 – 2006 • P.M. DeLuca, Jr. 2006 – 2009 • Hans Menzel 2009 - Present Organization of Activities: Medical Applications: Diagnostic Therapeutic Non-Ionizing Quantities and Units Non-Medical Applications: Radiation Processing Environmental Basic Data: Cross Sections Material Specification Radiation Constants Medical Imaging Science • Medical Imaging - Assessment of Image Quality (Report 54) 1995 • Absorbed Dose Specification in Nuclear Medicine (Report 67) 2002 • Image Quality in Chest Radiography (Report 70) 2003 • Patient Dosimetry of X Rays used in Medical Imaging (Report 74) 2005 • Radiation Dosimetry and Image Quality Assessment in Computed Tomography (Report 87) 2012 Medical Radiation Oncology Prescribing, Recording, and Reporting Photon-Beam Therapy – Supplement (Report 62) 1999 • Prescribing, Recording, and Reporting Electron Beam Therapy (Report 71) 2004 • Prescribing, Recording, and Reporting Proton-Beam Therapy (Report 78) 2007 •Prescribing, Recording, and Reporting Intensity-Modulated Photon-Beam Therapy (IMRT) (Report 83) 2010 •Prescribing, Recording, and Reporting Stereotactic Treatments with Small Photon Beams (in press) Work About to be published: Medical Radiation Oncology Area Reports with Radiation Protection Focus ICRU Report No. 53 (1994) • Ground level spectrometry • Airborne spectrometry • Determination of dose quantities ICRU Report No. 68 (2002) • Measurements on individuals (physical, biological) • environmental measurements + modelling (luminescence, mass spectrometry) • Radionuclides in environment ICRU Report No. 69 (2003) “Whole Body counter” • Types of detectors • Measurement geometries • Background reduction • Calibration Reference Data for Cosmic Radiation Exposure of Aircraft Crew Low Dose Exposures Radon Measurements (new) All ICRU Reports are published by OUP System of radiation protection dosimetry Physical quantities • Fluence, • Kerma, K • Absorbed dose, D ICRU Q(L) Comparison & estimation Operational quantities • Ambient dose equivalent, H*(d) • Directional dose equivalent, H’(d, ) • Personal dose equivalent, Hp(d) ICRP Protection quantities • Organ absorbed dose, DT • Organ equivalent dose, HT • Effective dose, E Related by calibration and calculation Monitored quantities Instrument responses 6 wR ICRU is currently reviewing/revising operational quantities • New dose conversion coefficients for effective dose in ICRP 116 extend to much higher energies than ICRP74 / ICRU57 • Dose conversion coefficients for operational quantities underestimate those for E at high enrergies • ICRU tissue cannot be manufactured • Reduced dose limit for the lens of the eye: new modeling required Current Report Activities • Radiation Monitoring for Protection of the Public after Major Releases of Radionuclides to the Environment • Methods for Initial-phase Assessment of Individual Doses Following Acute Exposure to Ionizing Radiation Thank you for the invitation and for your interest. 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