Performance Enhanced Ultrasound Probe Tracking With a Hemispherical Marker Rigid Body.

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Surgical Navigation

Background:

• Camera-based tracking is a mature technique for 3-D freehand ultrasound (US).
• Existing marker rigid bodies limit the US probe's rotational range due to self-occlusion issues.
• Accurate tracking is crucial for robust performance in US-guided procedures.

Purpose of the Study:

• To develop a novel hemispherical marker rigid body for passive noncoplanar markers.
• To mitigate self-occlusion and expand the rotational range of US probe tracking.
• To evaluate the tracking accuracy and data capture performance of the new system.

Main Methods:

• Designed a hemispherical marker rigid body to hold passive noncoplanar markers.
• Integrated the marker body into a camera-based tracking system for 3-D freehand ultrasound.
• Evaluated single-axis rotational and translational tracking performance at distances of 1.5-2 m.
• Assessed data capture rates and performed volume reconstruction using a fetal phantom.

Main Results:

• Achieved high tracking accuracy: 0.57° for rotation and 0.01 mm for translation.
• Captured over 99.76% of motion data, reducing missing data from >15% to <0.5%.
• Demonstrated successful volume reconstruction of a fetal phantom using the enhanced tracking data.

Conclusions:

• The proposed hemispherical marker rigid body significantly enhances tracking freedom and robustness for 3-D freehand ultrasound.
• The system provides high accuracy and reduces data loss, enabling reliable postprocessing and imaging.
• This advancement offers greater flexibility for sonographers during examinations and improves the quality of reconstructed US images.