[Development and evaluation of a positioning system for radiotherapy patient based on structured light surface...

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Image Processing

Context:

• Accurate patient positioning is critical in radiotherapy to ensure precise radiation delivery and minimize off-target exposure.
• Current positioning methods may involve surface markers or additional imaging, potentially increasing patient burden or radiation dose.
• Structured light surface imaging offers a noninvasive alternative for real-time patient setup verification.

Purpose:

• To propose and evaluate a novel noninvasive radiotherapy patient positioning system utilizing structured light surface imaging.
• To assess the system's accuracy, reliability, and clinical feasibility compared to established methods like Cone Beam CT (CBCT).
• To determine the system's ability to calculate six degrees of freedom (DoF) positioning deviations for couch shift correction.

Summary:

• Structured light sensors capture real-time panoramic point clouds for patient surface imaging during radiotherapy setup.
• Algorithms for point cloud fusion, coordinate transformation, segmentation, and registration (RANSAC, ICP) were employed to calculate positioning deviations.
• System performance was validated using a phantom and volunteers, demonstrating high accuracy with maximum errors of (1.5 ± 0.9) mm and (0.7 ± 0.3)° for translation and rotation, respectively, against CBCT gold standard.

Impact:

• The proposed system provides accurate, noninvasive patient positioning without the need for surface markers or additional radiation doses.
• Achieved high correlation coefficients (0.80-0.84) and Area Under the Curve (AUC) values (0.82-0.85) in validation analyses.
• Demonstrates significant potential for clinical application, improving radiotherapy workflow efficiency and patient safety.