Overview of ICRP Respiratory Tract Model

A special Task Group of the International Commission on Radiological Protection (ICRP) was created to review the dosimetric model of the respiratory tract and propose revisions or a new model. The Task Group directed its efforts toward improving the model used in Publication 30 rather than developing a completely new model. The objective was a model that would (1) facilitate calculation of biologically meaningful doses; (2) be consistent with morphological, physiological, and radiobiological characteristics of the respiratory tract; (3) incorporate current knowledge; (4) meet all radiation protection needs; (5) be user friendly, i.e. not unnecessarily sophisticated; (6) be adaptable to development of computer software for calculation of relevant radiation doses from knowledge of a few readily measured exposure parameters; (7) be equally useful for assessment purposes as for calculating annual limits on intake; (8) be applicable to all members of the world population; and (9) consider the influences of smoking, air pollutants, and diseases on the inhalation, deposition, and clearance of radioactive particles from the respiratory tract. Rather than calculating an average dose to the total lungs, emphasis was given to calculating specific tissue doses that could be used in the ICRP radiation protection system.