Analysis and evaluation of periodic physiological organ motion in radiotherapy treatments.

BACKGROUND AND PURPOSE A system for the detection, measurement and analysis of the periodic physiological organ motion during radiotherapy treatment is proposed and clinically tested in this paper. MATERIAL AND METHODS The procedure is based on the acquisition of fluoroscopic sequences, followed by an automatic detection of the movement using cross-correlations with matched filters. RESULTS The system generates a probability density function (PDF) of finding a mobile organ in a position at a certain time. The maximum path of the mobile structures can be determined to define the planning target volume (PTV) without ambiguities. CONCLUSIONS Physiological movements can be accurately included in the daily planning routine, which is not essentially modified, without needing previous patient training.