Technical note: Extended longitudinal and lateral 3D imaging with a continuous dual-isocenter CBCT scan

Area of Science:

• Medical Imaging
• Orthopedic Surgery
• Robotics

Background:

• Intraoperative cone beam CT (CBCT) enhances orthopedic surgery accuracy and provides immediate verification.
• Current CBCT limitations exist for long and wide anatomical sites common in orthopedic interventions.

Purpose of the Study:

• To investigate a novel imaging trajectory for CBCT to expand the field-of-view longitudinally and laterally.
• To assess the feasibility of this expanded imaging for all orthopedic procedures.

Main Methods:

• A continuous dual-isocenter imaging trajectory was implemented on a clinical robotic CBCT system.
• The trajectory involved circular arcs with alternating lateral and longitudinal table translations.
• Image quality was assessed using RMSD, MAPD, SSIM, and CNR, comparing against stitched conventional acquisitions.

Main Results:

• The novel trajectory achieved an imaging volume of 95 cm × 45 cm × 45 cm.
• This volume captured the entire lower body of a whole-body phantom.
• The new method used approximately half the imaging dose and acquisition time compared to conventional methods, with comparable image quality metrics.

Conclusions:

• Extended longitudinal and lateral intraoperative volumetric imaging is feasible using clinical robotic CBCT systems.
• This advancement can extend the benefits of intraoperative CBCT to a wider range of orthopedic procedures.