title: Development of a smart holmium:YAG laser lithotriptor.
abstract: OBJECTIVE
  The purpose of this study was to develop a feedback control system for the pulsed holmium:YAG medical laser that enhances tissue selectivity and safety by discriminating between soft and hard biological tissue such as urinary and biliary calculi and bone.
  
  
  METHODS
  The ability to discriminate is achieved by monitoring prompt laser-induced visible/NIR photoemissions via retrograde transmission over the laser delivery fiber in conjunction with a developed detection algorithm.
  
  
  RESULTS
  Experimental data are presented for a system that employs this discrimination scheme with an electro-optic shutter for rapid intrapulse feedback control of holmium laser-based lithotripsy procedures. The results demonstrate the feasibility of a lithotriptor that can deliver 1 J per pulse to calculi yet limit errant discharges to surrounding urinary tract tissue to < or = 0.1 J.
  
  
  CONCLUSIONS
  Based on animal tissue safety data, the laser margin of safety is improved by an order of magnitude.
authors.affiliation: Physical Sciences Inc., Andover, MA 01810, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Goldey
authors.forename: D I
authors.initials: DI
authors.lastname: Rosen
authors.forename: G B
authors.initials: GB
authors.lastname: Hayes
authors.forename: M K
authors.initials: MK
authors.lastname: Willscher
authors.forename: R A
authors.initials: RA
authors.lastname: Roth
mesh_terms: D000465:Algorithms; D000818:Animals; D004867:Equipment Design; D005240:Feasibility Studies; D005246:Feedback; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D017602:Lithotripsy, Laser / Q000295:instrumentation* / Q000379:methods; D011817:Rabbits