Standard clinical management of extremity soft tissue sarcomas includes surgery with radiation therapy. Wound complications (WCs) arising from treatment may occur due to bacterial infection and tissue breakdown. The ability to detect changes in these parameters during treatment may lead to earlier interventions that mitigate WCs. We describe the use of a new system composed of an autofluorescence imaging device and an optical three-dimensional tracking system to detect and coregister the presence of bacteria with radiation doses. The imaging device visualized erythema using white light and detected bacterial autofluorescence using 405-nm excitation light. Its position was tracked relative to the patient using IR reflective spheres and registration to the computed tomography coordinates. Image coregistration software was developed to spatially overlay radiation treatment plans and dose distributions on the white light and autofluorescence images of the surgical site. We describe the technology, its use in the operating room, and standard operating procedures, as well as demonstrate technical feasibility and safety intraoperatively. This new clinical tool may help identify patients at greater risk of developing WCs and investigate correlations between radiation dose, skin response, and changes in bacterial load as biomarkers associated with WCs.
A prototype mobile C-arm for cone-beam CT (CBCT) has been translated to a prospective clinical trial in head and neck
surgery. The flat-panel CBCT C-arm was developed in collaboration with Siemens Healthcare, and demonstrates both
sub-mm spatial resolution and soft-tissue visibility at low radiation dose (e.g., <1/5th of a typical diagnostic head CT).
CBCT images are available ~15 seconds after scan completion (~1 min acquisition) and reviewed at bedside using
custom 3D visualization software based on the open-source Image-Guided Surgery Toolkit (IGSTK). The CBCT C-arm
has been successfully deployed in 15 head and neck cases and streamlined into the surgical environment using human
factors engineering methods and expert feedback from surgeons, nurses, and anesthetists. Intraoperative imaging is
implemented in a manner that maintains operating field sterility, reduces image artifacts (e.g., carbon fiber OR table) and
minimizes radiation exposure. Image reviews conducted with surgical staff indicate bony detail and soft-tissue
visualization sufficient for intraoperative guidance, with additional artifact management (e.g., metal, scatter) promising
further improvements. Clinical trial deployment suggests a role for intraoperative CBCT in guiding complex head and
neck surgical tasks, including planning mandible and maxilla resection margins, guiding subcranial and endonasal
approaches to skull base tumours, and verifying maxillofacial reconstruction alignment. Ongoing translational research
into complimentary image-guidance subsystems include novel methods for real-time tool tracking, fusion of endoscopic
video and CBCT, and deformable registration of preoperative volumes and planning contours with intraoperative CBCT.