Further study of the effect of particle size on slow particle clearance from the bronchial tree

Jenny R.H. Smith*, M. R. Bailey, G. Etherington, A. I. Shutt, M. J. Youngman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The ICRP human respiratory tract model (HRTM) assumes that the 'slow-cleared fraction' fs in the bronchial (BB) and bronchiolar (bb) regions decreases with increasing particle geometric diameter dp. To test this assumption, five volunteers inhaled 8-μm aerodynamic diameter, dae, 111In- polystyrene (PSL) and 198Au particles simultaneously. The particles were administered at the end of each breath to maximise deposition in BB and bb. Because of the difference in densities (1.05 vs. 19.3 g cm-3), corresponding dp values are ∼8 and 1.8 μm, and fs values are ∼2 and 50%, respectively. However, lung retention was somewhat greater for PSL than for gold, contrary to the HRTM prediction. Other recent human experimental studies found no difference in retention for particles with the same dae but different dp values. It is concluded that the HRTM model of particle clearance from BB and bb needs revision.

Original languageEnglish
Pages (from-to)35-39
Number of pages5
JournalRadiation Protection Dosimetry
Issue number1-4
Publication statusPublished - 2007

Bibliographical note

Funding Information:
We are grateful to the volunteers for their invaluable co-operation, to Dr J. Scott and Mrs S. Hodgson for assistance with measurements and Professor W. Hofmann and Dr R. Winkler-Heil (University of Salzburg) for deposition calculations. The study was partly funded by the European Commission under Contract FIGD-CT2000-00053.


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