Purpose: To adapt a commercial CT-based neurosurgical navigation system for use in interstitial liver procedures and validate its performance on a representational liver phantom. CT-based navigation technology has been shown to improve efficacy and safety in neurosurgical procedures and offers potential to do the same for interstitial liver procedures, which are used in radiation oncology practice for implanting targeting fiducials or brachytherapy source transfer needles to facilitate precise delivery of radiation to lesions.
Methods: A mobile intraoperative CT scanner and partnered optical-tracking navigation system were used as the imaging and navigation platforms. The default neurosurgical navigation software was augmented to display segmented structures from radiation-therapy treatment-planning software, enabling visualization of target and avoidance structures during image-guided needle placement. Fiducial needles were tested for compatibility and reliability with the navigation system. A phantom was fabricated in house containing pseudo costal/vascular avoidance structures and lesions visible on CT images, and this phantom was used to test the radiation oncologist’s ability to accurately and reproducibly place fiducials in a target region without intersecting avoidance structures.
Results: The navigation software was successfully modified to receive and display physician-drawn segmented structures, and this feature was utilized in tests involving the pseudo liver phantom. A pre-loaded fiducial needle was found to be compatible with the optical-tracking system and its tip location was accurately and reproducibly tracked in the navigation environment. The pseudo liver phantom was accurately and reproducibly implanted with fiducials in pre-planned locations by the radiation oncologist.
Conclusion: We adapted a CT-based navigation system for use in interstitial liver procedures and developed a pseudo liver phantom to test the accuracy and reproducibility of navigated fiducial placement at pre-planned target locations in a controlled, simulated setting. This system could facilitate safe practices for fiducial-marker and/or brachytherapy-needle placement and permit faster radiation treatment throughput.