Purpose: The application of contrast and tracing agents is essential for lung imaging, as indicated by the wide use in recent decades and the discovery of various new contrast and tracing agents. Different aerosol production and pulmonary administration methods have been developed to improve lung imaging quality. This review details and discusses the ideal characteristics of aerosol administered via pulmonary delivery for lung imaging and the methods for the production and pulmonary administration of dry or liquid aerosol.
Methods: We explored several databases, including PubMed, Scopus, and Google Scholar, while preparing this review to discover and obtain the abstracts, reports, review articles, and research papers related to aerosol delivery for lung imaging and the formulation and pulmonary delivery method of dry and liquid aerosol. The search terms used were "dry aerosol delivery", "liquid aerosol delivery", "MRI for lung imaging", "CT scan for lung imaging", "SPECT for lung imaging", "PET for lung imaging", "magnetic particle imaging", "dry powder inhalation", "nebuliser", and "pressurised metered-dose inhaler".
Results: Through the literature review, we found that the critical considerations in aerosol delivery for lung imaging are appropriate lung deposition of inhaled aerosol and avoiding toxicity. The important tracing agent was also found to be Technetium-99m (99mTc), Gallium-68 (68Ga) and superparamagnetic iron oxide nanoparticle (SPION), while the essential contrast agents are gold, iodine, silver gadolinium, iron and manganese-based particles. The pulmonary delivery of such tracing and contrast agents can be performed using dry formulation (graphite ablation, spark ignition and spray dried powder) and liquid aerosol (nebulisation, pressurised metered-dose inhalation and air spray).
Conclusion: A dual-imaging modality with the combination of different tracing or contrast agents is a future development of aerosolised micro and nanoparticles for lung imaging to improve diagnosis success.
Keywords: Aerosol; Lung imaging; Micro- or nanoparticle; Pulmonary delivery.
© The Author(s), under exclusive licence to Italian Association of Nuclear Medicine and Molecular Imaging 2022, Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.