Examining the ability of empirical correlations to predict subject specific in vivo extrathoracic aerosol deposition during tidal breathing

• Published in: Aerosol science and technology Vol. 51; no. 3; pp. 363 - 376
• Main Authors: Yang, Michael Y., Ruzycki, Conor, Verschuer, Jordan, Katsifis, Andrew, Eberl, Stefan, Wong, Keith, Golshahi, Laleh, Brannan, John D., Finlay, Warren H., Chan, Hak-Kim
• Format: Journal Article
• Language: English
• Published: New York Taylor & Francis 04.03.2017; Taylor & Francis Ltd
• Subjects: Aerosol research; Aerosols; Atmospheric chemistry; Copyrights; Correlation coefficient; Deposition; Mathematical analysis; Mathematical models; Predictions; Saline; Standard deviation; Yannis Drossinos
• ISSN: 0278-6826; 1521-7388; 1521-7388
• DOI: 10.1080/02786826.2016.1262532

The accuracy of five extrathoracic deposition equations was examined by comparing model predictions with in vivo deposition measurements of 99m Tc-DTPA radiolabeled 0.9% saline delivered via PARI LC Sprint nebulizers in 19 healthy human subjects. The average extrathoracic deposition fraction measured in vivo was 0.19 ± 0.10 (average ± standard deviation). Comparing to this average value, the extrathoracic deposition fraction predicted by Golshahi et al. equation was the most accurate (0.18 ± 0.08), followed by the model described by the ICRP (0.16 ± 0.03). However, prediction of subject-specific deposition proved more challenging; the Golshahi et al. model performed the best of the examined equations, yet showed only a small positive correlation between measured and predicted deposition in individual subjects with a Pearson correlation coefficient of 0.34. The difficulties in predicting subject-specific deposition likely result from geometric dissimilarity both within and between subjects, and may require more complicated modeling methods than algebraic equations of the kind examined in this study. Copyright © 2017 American Association for Aerosol Research