A novel SGRT system for real-time optical surface tracking or guidance

Area of Science:

• Medical Physics
• Optical Imaging
• Radiation Therapy Technology

Background:

• Optical 3D surface imaging reconstructs patient surfaces without markers.
• Surface-guided radiation therapy (SGRT) relies on accurate surface tracking.

Purpose of the Study:

• Evaluate the novel LUNA 3D system for SGRT.
• Assess static and dynamic accuracy under various conditions (color, lighting, ROI size).

Main Methods:

• Used a 6DoF robot stage with head phantoms for accuracy testing.
• Employed an infrared (IR) tracking camera for secondary verification.
• Utilized blue light projection and narrow bandpass filters to mitigate environmental variations.

Main Results:

• Achieved sub-millimeter translational (0.04-0.06 mm) and sub-degree rotational (0.04°) accuracy for static phantoms.
• Showed minimal difference (max 0.14 mm) compared to IR tracking across varying conditions.
• Maintained a consistent frame rate of 12.5 fps regardless of Region of Interest (ROI) size.

Conclusions:

• LUNA 3D provides high sub-millimeter/sub-degree tracking accuracy.
• Demonstrated robustness against surface color and ambient light changes.
• Offered stable frame rate performance irrespective of ROI size, suitable for SGRT.