title: Evaluation of Endoscopically Deployed Radiopaque Tumor Models in Bronchoscopy.
abstract: BACKGROUND
  Radiopaque markers and soft tissue models have been used extensively in clinical applications to target cancerous lesions and to calibrate and characterize imaging systems. However, the development of radiopaque, soft tissue models for pulmonary lesions is yet to be optimized. Such a material may improve endoscopic training techniques and also be useful to evaluate bronchoscopy navigation systems by the targeting and sampling of tumor models with computed tomography.
  
  
  METHODS
  This study investigates a modified agarose-based model and a novel contrast-infused tripe model to create clinically relevant pulmonary tumor models. An iodine-enhanced agarose model presents an injectable solution with high image contrast under computed tomography capable of reaching distal bronchial airways. The tripe solution presents a cheap and easily deployed method to quickly establish a fiducial marker that may be used during bronchial imaging system training and evaluation.
  
  
  RESULTS
  The iodine-enriched agarose model demonstrates desirable mechanical characteristics ex vivo, but has a number of limitations when administered in a live setting. The tripe solution presents a far more effective in vivo pulmonary tumor model and offers an effective radiopaque marker. However, the size of the tripe tumor samples required for effective insertion limits its ability to reach more distal airways. An iterative testing process was used to optimize the model composition, culminating in live animal investigations (n=3).
  
  
  CONCLUSIONS
  Both contrast-infused agarose and tripe models present a promising analog to a pulmonary lesion and may act as a radiopaque marker for bronchoscopic training and biopsy evaluation.
authors.affiliation: *School of Engineering, University College Cork †Respiratory Medicine, Cork University Hospital, Cork, Ireland.
authors.forename: Conor
authors.initials: C
authors.lastname: O'Shea
authors.forename: Kashif
authors.initials: K
authors.lastname: Ali Khan
authors.forename: Pietro
authors.initials: P
authors.lastname: Nardelli
authors.forename: Herman Alex
authors.initials: HA
authors.lastname: Jaeger
authors.forename: Marcus P
authors.initials: MP
authors.lastname: Kennedy
authors.forename: Pádraig
authors.initials: P
authors.lastname: Cantillon-Murphy
mesh_terms: D000818:Animals; D001999:Bronchoscopy / Q000379:methods*; D057918:Fiducial Markers; D006801:Humans; D008168:Lung / Q000033:anatomy & histology*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008954:Models, Biological; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods