Regional deposition of 2.5–7.5 μm diameter inhaled particles in healthy male non-smokers

Abstract

Airborne monodisperse particles in the size range 2.5–7.5 μm dia., labelled with 99mTc, were systematically administered to mouth breathing subjects under different but predetermined breathing patterns ranging from 0.5–2.01, tidal volume and 10–25 breaths/min. The subjects were all healthy, non-smoking males. Measurements were made of both total and regional deposition. The results show the increasing significance of pulmonary deposition as the particle size decreases and consequently the importance of accurate data in this range for the purposes of radiological protection. Both total and regional deposition are a function of the impaction parameter ( D 2 F) suggesting that inertial impaction is the main mechanism of deposition under the conditions studied. The work supports the predicted values of deposition given in the lung model of the International Commission on Radiological Protection. Subsidiary experiments showed the value of faecal sampling in establishing the accuracy of total deposition estimates and in elucidating full regional deposition.