The bronchial dosemeter

It has been known for some decades that most of the radiation dose to the lung is due to the inhalation of the short-lived decay products of ²²²Rn. Their deposition in the respiratory tract depends strongly on the attachment rate to aerosol particles present in indoor air and their plateout rate to surfaces. Instead of measuring the activity size distribution of the airborne decay products, knowledge of the respiratory tract retention has been incorporated in the design of a measurement system, called a bronchial dosemeter, to assess the lung dose directly. The simulation of the deposition characteristics of the short-lived radon daughters in the nasal cavity and the bronchial tree is based on the comparison of the model of the respiratory tract with results from screen penetration theory. A bronchial dosemeter consisting of three sampling heads has been built and calibrated.