CALIBRATION OF BRACHYTHERAPY ROBOTIC SYSTEM FOR PERMANENT RADIOACTIVE SEED IMPLANTS

摘要

Effective calibration procedure plays a crucial role for thernclinical implementation of an image-guidedrnbrachytherapy robotic system. This article describes arncomprehensive calibration procedure for such a system.rnTo meet stringent demands for precise placement ofrnradioactive sources, the system resolution, repeatabilityrnand accuracy have been carefully investigated. Thernimaging performance and proper transformation fromrnultrasound images to the metric distance in robot absoluterncoordinates have been analyzed in details. The method forrnthe image stack positioning in absolute coordinates wasrndeveloped to minimize the influence of repeatable andrnrandom errors to the system using numerical optimization.rnThe error between the measured position and the positionrnpredicted by the nominal kinematic parameters isrnemployed in an iterative nonlinear estimation procedure tornadjust the kinematic parameters to their true values.rnExperimental results have been presented as a part of thernsystem calibration.