Cone beam tomosynthesis fluoroscopy: a new approach to 3D image guidance

摘要

Fluoroscopy is a common image guidance modality used in spine and orthopedic surgery. One benefit of this technology is that it provides real-time images without interrupting the procedure. A major challenge with fluoroscopy is that it provides projection images with no depth information, limiting surgical accuracy in complex procedures like for example in thoracic spine surgery. 3D technologies such as intraoperative Cone Beam CT and surgical navigation solve the surgical accuracy problem but increase cost and impair the surgical workflow, limiting its adoption. In an attempt to improve surgical accuracy, control costs and simplify the surgical workflow, a new approach to image guidance based on real-time 3D imaging is proposed. Fast fluoroscopic acquisitions taken in a circular tomosynthesis geometry' are used to provide near real-time 3D updates of the imaged surgical scene. 3D updates are achieved via a model-based reconstruction that makes proficient use of prior information, and instrument tracking is achieved via image processing. This new imaging approach is named Cone Beam Tomosynthesis (CBT) fluoroscopy. A first prototype based on a modified C-arm and with a single rotating source is used to assess the surgical performance of CBT-fluoroscopy. Preliminary results show that CBT-fluoroscopy can achieve near-real-time imaging performance and provide comparable surgical accuracy to fluoroscopy in the use case of pedicle screw placement on phantoms; the limitations of the approach are analyzed and steps to address these limitations are discussed.