title: Assessing sinus aerosol deposition: benefits of SPECT-CT imaging.
abstract: OBJECTIVE
  Aerosol inhalation therapy is one of the methods to treat rhinosinusitis. However the topical drug delivery to the posterior nose and paranasal sinuses shows only limited efficiency. A precise sinusal targeting remains a main challenge for aerosol treatment of sinus disorders. This paper proposes a comparative study of the nasal deposition patterns of micron and submicron particles using planar gamma-scintigraphy imaging vs. a new 3-dimensional (3D) imaging approach based on SPECT-CT measurements.
  
  
  METHODS
  Radiolabelled nebulizations have been performed on a plastinated model of human nasal cast coupled with a respiratory pump. First, the benefits provided by SPECT-CT imaging were compared with 2D gamma-scintigraphy and radioactive quantification of maxillary sinus lavage as reference for the sonic 2.8 μm aerosol sinusal deposition. Then, the impact on nasal deposition of various airborne particle sizes was assessed.
  
  
  RESULTS
  The 2D methodology overestimates aerosol deposition in the maxillary sinuses by a factor 9 whereas the 3D methodology is in agreement with the maxillary sinus lavage reference methodology. Then with the SPECT-CT approach we highlighted that the higher particle size was mainly deposited in the central nasal cavity contrary to the submicron aerosol particles (33.8 ± 0.6% of total deposition for the 2.8 μm particles vs. 1 ± 0.3% for the 230 nm particles).
  
  
  CONCLUSIONS
  Benefits of SPECT/CT for the assessment of radiolabelled aerosol deposition in rhinology are clearly demonstrated. This 3D methodology should be preferentially used for scintigraphic imaging of sinusal deposition in Human.
authors.affiliation: Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; Ecole Nationale Supérieure des Mines, CIS-EMSE, LINA EA 4624, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France. Electronic address: lara.leclerc@univ-st-etienne.fr.
authors.forename: Lara
authors.initials: L
authors.lastname: Leclerc
authors.affiliation: Ecole Nationale Supérieure des Mines, CIS-EMSE, LINA EA 4624, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Pourchez
authors.affiliation: Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France; CHU de Saint-Etienne, Nuclear Medicine Department, F-42055 Saint-Etienne, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Prevot
authors.affiliation: Centre d'Etudes des Pathologies Respiratoires INSERM U1100/EA 6305, Faculté de Médecine, Université François Rabelais, Tours, France; DTF Aerodrug, Faculté de Médecine, Université François Rabelais, Tours, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Vecellio
authors.affiliation: Centre d'Etudes des Pathologies Respiratoires INSERM U1100/EA 6305, Faculté de Médecine, Université François Rabelais, Tours, France; DTF Aerodrug, Faculté de Médecine, Université François Rabelais, Tours, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Le Guellec
authors.affiliation: Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France.
authors.forename: Michèle
authors.initials: M
authors.lastname: Cottier
authors.affiliation: Université Jean Monnet, LINA EA 4624, Université de Lyon, F-42023 Saint-Etienne, France; SFR IFRESIS, F-42023 Saint-Etienne, France; Centre Hospitalier Emile Roux, ENT Department, F-43012 Le Puy en Velay, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Durand
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D016503:Drug Delivery Systems; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008953:Models, Anatomic; D009296:Nasal Cavity / Q000378:metabolism*; D010256:Paranasal Sinuses / Q000378:metabolism; D010316:Particle Size; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000336:Aerosols
keywords: Aerosol deposition; Aerosol therapy; SPECT/CT imaging