CALIBRATION OF BRACHYTHERAPY ROBOTIC SYSTEM FOR PERMANENT RADIOACTIVE SEED IMPLANTS

摘要

Effective calibration procedure plays a crucial role for the clinical implementation of an image-guided brachytherapy robotic system. This article describes a comprehensive calibration procedure for such a system. To meet stringent demands for precise placement of radioactive sources, the system resolution, repeatability and accuracy have been carefully investigated. The imaging performance and proper transformation from ultrasound images to the metric distance in robot absolute coordinates have been analyzed in details. The method for the image stack positioning in absolute coordinates was developed to minimize the influence of repeatable and random errors to the system using numerical optimization. The error between the measured position and the position predicted by the nominal kinematic parameters is employed in an iterative nonlinear estimation procedure to adjust the kinematic parameters to their true values. Experimental results have been presented as a part of the system calibration.