ICRP dose coefficients: computational development and current status

Abstract

Major current efforts within Committee 2 of the International Commission on Radiological Protection (ICRP) involve the development of dose coefficients for inhalation and ingestion of radionuclides, and those for exposure to environmental radiation fields. These efforts build upon changes in radiation and tissue weighting factors (Publication 103), radionuclide decay schemes (Publication 107), computational phantoms of the adult reference male and female (Publication 110), external dose coefficients for adult reference workers for idealised radiation fields (Publication 116), models of radionuclide intake (Publications 66, 100 and 130), and models of radionuclide systemic biokinetics (Publication 130). This paper will review the overall computational framework for both internal and external dose coefficients. For internal exposures, the work entails assessment of organ self-dose and cross-dose from monoenergetic particle emissions (specific absorbed fraction), absorbed dose per nuclear transformation (S value), time-integrated activity of the radionuclide in source tissues (inhalation, ingestion, and systemic biokinetic models), and their numerical combination to yield the organ equivalent dose or effective dose per activity inhaled or ingested. Various challenges are reviewed that were not included in the development of Publication 30 dose coefficients, which were based upon much more simplified biokinetic models and computational phantoms. For external exposures, the computations entail the characterisation of environmental radionuclide distributions, the transport of radiation particles through that environment, and the tracking of energy deposition to the organs of the exposed individual. Progress towards the development of dose coefficients to members of the general public (adolescents, children, infants and fetuses) are also reviewed.

The mandate and work of ICRP Committee 2 on doses from radiation exposure

“…Corresponding members are Chansoo Choi (Korea), Beom Sun Chung (Korea), Min Cheol Han (Korea), Keith Eckerman, Han Sung Kim (Korea), Thang Tat Nguyen (Vietnam), and Rui Qiu (China). Bolch et al (2016) and Zankl et al (2018) discuss the development of Publication 110 (ICRP, 2009) reference phantoms for the adult male and female, and reference phantoms for children of different ages: newborn, 1 year, 5 years, 10 years, and 15 years. Models are also being developed for the fetus and pregnant female at various gestational ages (Bolch et al, 2016).…”

“…Bolch et al (2016) and Zankl et al (2018) discuss the development of Publication 110 (ICRP, 2009) reference phantoms for the adult male and female, and reference phantoms for children of different ages: newborn, 1 year, 5 years, 10 years, and 15 years. Models are also being developed for the fetus and pregnant female at various gestational ages (Bolch et al, 2016). These dosimetric models are being used to provide reference radiation transport data in the form of specific absorbed fractions (SAFs) for radiations emitted from radionuclides retained in body organs and tissues.…”