Photon-Counting Computed Tomography Enables Image-Guided Navigation of the Paranasal Sinuses at Ultra-Low Radiation Dose: An Initial Cadaveric Study

Background/Objectives: Photon-counting computed tomography (PCCT) enables substantial radiation dose reduction while preserving high spatial resolution. Its potential for image-guided navigation in endoscopic sinus surgery (ESS), particularly at ultra-low dose levels, remains insufficiently explored. This study aimed to evaluate the feasibility of PCCT for four different surgical navigation systems at progressively reduced radiation doses. Methods: PCCT datasets of the paranasal sinuses were acquired from two cadaveric specimens using a standard protocol followed by stepwise dose reductions down to 5% of the reference dose. The datasets were used for image-guided navigation with four systems (one optical, three electromagnetic). Registration success, navigation accuracy, and user satisfaction (visual analog scale) were assessed at 100% and 5% dose levels using linear mixed-effects models. Results: Registration was successful for all navigation systems at every dose level. Mean navigation accuracy remained stable despite dose reduction (2.22 ± 1.16 mm at 100% vs. 1.93 ± 1.05 mm at 5% radiation dose; p = 0.364). User satisfaction regarding navigation was consistently high (mean 8.8 ± 0.75) and showed no significant differences between dose levels. Conclusions: PCCT enabled image-guided navigation even at ultra-low radiation doses down to 5% of standard exposure, without compromising navigation accuracy in this initial study. These findings highlight the potential of PCCT to substantially reduce radiation burden while maintaining clinical performance. Further in-human studies are needed.