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Draft Joint Report of ICRU and ICRP for Consultation: Operational Quantities for External Radiation ExposureThe draft ICRU and ICRP report Operational Quantities for External Radiation Exposure is now available for public consultation. We welcome comments from individuals and organisations. The draft document can be downloaded from the ICRP website. Comments must be submitted through the ICRP website no later than November 3, 2017.
The Commission defines a set of operational dose quantities for the determination of the exposure of external radiation by measurement or calculation. These assessments serve as estimates of values of the protection quantities defined by the International Commission on Radiological Protection (ICRP) that are generally not measurable. The set of ICRU operational dose quantities in current use was defined 30 years ago. The rationale for operational quantities has been examined taking into account the recent changes in the definitions of the protection quantities (ICRP, 2010); the changes in the fields of application of the operational quantities and protection quantities in medicine, scientific research, and natural sources of radiation; and the extension of types of particles and range of energies contributing to doses to workers and members of the public. The previous operational quantities were based on the dose equivalent that would be produced at a depth in the hypothetical ICRU 4-element sphere, and on dose equivalent in soft tissue at a point in the body. The investigations which have been carried out that have led to the recommendations given in this Report have included the study the values of weighted absorbed doses at different depths in tissue-equivalent phantoms and the combination of different depths. The operational quantities recommended in this Report are defined in terms of radiometric and dosimetric quantities at a point in space multiplied by values of conversion coefficients to the protection quantities, effective dose, absorbed dose in the lens of the eye, and absorbed dose in local skin, calculated for broad parallel beams incident on the body. The relationship of the recommended operational quantities to the protection quantities has been investigated. The impact of changes on routine measurement practice, including instrument design and calibration has been considered.