A visual probe positioning tool for 4D ultrasound-guided radiotherapy

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Medical Imaging

Background:

• Ultrasound (US) guidance is increasingly used in image-guided radiotherapy for real-time motion compensation.
• A significant drawback of US is its user dependency, requiring extensive clinical experience for high-quality results.
• Accurate probe positioning is crucial for effective ultrasound-guided interventions.

Purpose of the Study:

• To develop a visual guidance tool to assist non-experts in setting up ultrasound equipment.
• To improve the accuracy and reproducibility of ultrasound probe positioning in radiotherapy.
• To combine real-time US volume and CT visualization for enhanced guidance.

Main Methods:

• Development of a visual guidance tool integrating real-time 4D ultrasound data and CT visualization.
• Utilizing a geometrically calibrated setup with an optical tracking system for precise probe localization.
• Achieving calibration through a 4D US station with real-time data access.

Main Results:

• Achieved a calibration accuracy of 1.2 mm.
• Obtained a mean 2D contour distance of 1.7 mm between US and CT identified organ boundaries.
• Demonstrated good visual alignment of anatomical structures between modalities.

Conclusions:

• The developed probe positioning tool offers valuable assistance for ultrasound-guided radiotherapy setup by non-experts.
• The tool guides users to optimal acoustic windows, potentially enhancing setup reproducibility.
• This technology could benefit various image-guided interventions requiring precise ultrasound probe placement.