Room: Exhibit Hall
Purpose: Recently, three-dimensional scanning devices for patient setup and/or monitoring during radiation delivery are widely used in radiotherapy. The patient surface guiding provides not only 3D information for precise monitoring but also continuous change due to respiratory motion on chest/abdomen. The aims of this research are to manage patientâ€™s respiration by detecting wide-ranged area on patient surface to analyze the respiratory phase and to estimate suitable area automatically where the respiratory phase can be tracked accurately except on the central axis of the body surface.
Methods: We used VOXELAN (ERD Corporation) that can obtain 3D patientâ€™s body surface information. We constructed mathematical analysis model for respiratory control/monitoring on 3D patient body information. The continuous 3D surface data were divided into 3 Ã— 3 cm meshed area. On each area, the auto-correlation-function (ACF) was calculated to evaluate periodicity of respiration wave. Next, the cross-correlation-function (CCF) were calculated on each area to evaluate continous location misalighment. As fundamental experiments, the 3D surface scanning was performed for the anthropomorphic phantom which several periodic and/or random waves were set on. As clinical experiments, 10 patients were randomized chosen in this study.
Results: We evaluated 11 patterns of demonstrative motions were analyzed as fundamental experiments. In regular motions, the values both ACF and CCF were indicated approximately 1 (ranging from 0.9 to 1.0). In irregular motions, even though CCF was, however, indicated better value, ACF was indicated worse value. As result of clinical experiments, the strong correlation was observed in periodic motion. However, lower CCF was observed in random wave even though desirable value of ACF was observed.
Conclusion: With combination of ACF and CCF analyses, this system provide not only estimation of suitable area for respiratory monitoring automatically but also respiratory control by observing at any suitable area continuously.