Real-time motion analysis for definition and control of patient position in radiotherapy

摘要

A computerized dedicated system for patient positioning and monitoring in radiotherapy is herein presented. The system is based on the motion analysis system ELITE, exploiting its real-time operation features. Core of the method is the analytical comparison between the 3D co-ordinates of a set of body landmarks with a corresponding reference configuration, previously acquired and memorized. The system provides in real-time the identification in the environment of the selected anatomical landmarks, highlighted by means of infrared light reflecting passive markers, their 3D co-ordinates calculation and the analytical comparison with the reference configuration. The detection of patient's breathing phases, considering the 3D co-ordinates of three suitable markers for the supine position, has allowed to synchronize the analytical comparison to patient's breathing FRC (Functional Residual Capacity) increasing accuracy and reliability of patient's position control. The real-time process is completed by displaying to the operator a synoptic graphic representation of the current marker displacements situation relative to the most recent patient's FRC. The experimental use of the developed system has brought to a significant reduction of the time required for the positioning procedure, reaching a suitable tradeoff between a quick irradiation set-up and a clinically correct patient irradiation.