Realistic reference phantoms: An ICRP/ICRU joint effort

In London in 1925, at the first International Congress of Radiology (ICR), the predecessor to the International Commission on Radiation Units and Measurements (ICRU) was created as the International X-ray Unit Committee. The International X-ray and Radium Protection Committee, predecessor to the International Commission on Radiological Protection (ICRP), was created in Stockholm in 1928 at the second ICR. Thus, ICRP and ICRU have a shared origin and many common interests. Although both organisations function independently, until the 1970s they usually met at the time and place of the ICR. They shared (and still share) many interests and, at times, many members including Lauriston Taylor, a pioneer and giant in the field of radiological protection. This publication represents a renewed collaboration between the two organisations, being the first in a series of planned joint efforts, with contributions from members of both ICRP and ICRU. In this case, ICRP has taken the lead, while ICRU will take the lead for some of the forthcoming publications. In addition, this report is vital to the full implementation of the 2007 Recommendations of ICRP (ICRP, 2007). The Recommendations formally define ‘reference phantoms’ as ‘voxel phantoms for the human body. . .’. The current report delivers the most important of these voxel phantoms: the adult male and adult female. Practical radiological protection for workers and the general public uses dosimetric quantities which quantify the exposure to ionising radiation appropriately for the implementation of the fundamental principles of limitation and optimisation. Radiation protection regulations and guidelines for demonstration of compliance are formulated in terms of reference or standard individuals. ICRP and ICRU have established a system of protection and operational dosimetric quantities which are based on reference data, models, and phantoms, and which have been shown to provide a satisfactory conceptual and practicable procedure for risk management of the low dose exposures of concern in radiological protection. It was recognised long before the introduction of the current system of protection and operational quantities that exposure assessment and monitoring of humans exposed to ionising radiation from external sources and from incorporated radionuclides requires the use of models and phantoms characterizing reference individuals. This led to the development of phantoms, i.e. physical models of the human body such as the ‘Rando’ phantom (Alderson et al., 1962), and computational anthropo-