The Effect of Transponder Motion on the Accuracy of the Calypso Electromagnetic Localization System
Received 20 February 2008; received in revised form 12 May 2008; accepted 14 May 2008.
Purpose
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 and Materials
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.
Reprint requests to: Martin J. Murphy, Ph.D., Department of Radiation Oncology, Virginia Commonwealth University Health System, 401 College Street, P.O. Box 980058, Richmond, VA 23298-0058. Tel: (804) 628-7777; Fax: (804) 628-4709
Supported in part by National Cancer Institute grant R21CA119143.
Conflict of interest: R.E., E.V., and J.N.W. are employees of Calypso Medical Technologies.
ABSTRACT