title: Feasibility of locating tumours in lung via kinaesthetic feedback.
abstract: BACKGROUND
  Localizing lung tumours during minimally invasive surgery is difficult, since restricted access precludes manual palpation and pre-operative imaging cannot map directly to the intra-operative lung. This study analyses the force-sensing performance that would allow an instrumented kinaesthetic probe to localize tumours based on stiffness variations of the lung parenchyma.
  
  
  METHODS
  Agar injected into ex vivo porcine lungs produced a model approximating commonly encountered tumours. Force-deformation data were collected from multiple sites at various palpation depths and velocities, before and after the tumours were injected.
  
  
  RESULTS
  Analysis showed an increase in force after the tumours were injected, in the range 0.07-0.16 N at 7 mm (p < 10(-4)). A 2 mm/s palpation velocity minimized exponential stress decay at constant depths, facilitating easier comparisons between measurements.
  
  
  CONCLUSIONS
  A sensing range of 0-2 N, with 0.01 N resolution, should allow a kinaesthetic palpation probe to resolve local tissue stiffness changes that suggest an underlying tumour.
authors.affiliation: Canadian Surgical Technologies & Advanced Robotics (CSTAR), London Health Sciences Centre, 339 Windermere Road, London, Ontario, Canada N6A 5A5.
authors.forename: G L
authors.initials: GL
authors.lastname: McCreery
authors.forename: A L
authors.initials: AL
authors.lastname: Trejos
authors.forename: M D
authors.initials: MD
authors.lastname: Naish
authors.forename: R V
authors.initials: RV
authors.lastname: Patel
authors.forename: R A
authors.initials: RA
authors.lastname: Malthaner
mesh_terms: D000818:Animals; D004548:Elasticity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005246:Feedback; D006244:Hardness; D006801:Humans; D007699:Kinesthesis; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000503:physiopathology*; D010173:Palpation / Q000295:instrumentation* / Q000379:methods*; D013552:Swine; D014159:Transducers