title: The effect of transponder motion on the accuracy of the Calypso Electromagnetic localization system.
abstract: OBJECTIVE
  To determine position and velocity-dependent effects in the overall accuracy of the Calypso Electromagnetic localization system, under conditions that emulate transponder motion during normal free breathing.
  
  
  METHODS
  Three localization transponders were mounted on a remote-controlled turntable that could move the transponders along a circular trajectory at speeds up to 3 cm/s. A stationary calibration established the coordinates of multiple points on each transponder's circular path. Position measurements taken while the transponders were in motion at a constant speed were then compared with the stationary coordinates.
  
  
  RESULTS
  No statistically significant changes in the transponder positions in (x,y,z) were detected when the transponders were in motion.
  
  
  CONCLUSIONS
  The accuracy of the localization system is unaffected by transponder motion.
authors: Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA 23298-0058, USA. mmurphy@mcvh-vcu.edu
authors: Martin J
authors: MJ
authors: Murphy
authors: Richard
authors: R
authors: Eidens
authors: Edward
authors: E
authors: Vertatschitsch
authors: J Nelson
authors: JN
authors: Wright
mesh_terms: D002138:Calibration; D055590:Electromagnetic Phenomena / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D009038:Motion; D011846:Radio Waves; D015203:Reproducibility of Results; D012119:Respiration; D013679:Technology, Radiologic / Q000295:instrumentation / Q000379:methods