Estimating distributions of manual fiducial localization in CT images

Purpose The fiducial localization error distribution (FLE) and fiducial configuration govern the application accuracy of point-based registration and drive target registration error (TRE) prediction models. The error of physically localizing patient fiducials (FLEpatient) is negligible when a registration probe matches the implanted screws with mechanical precision. Reliable trackers provide an unbiased estimate of the positional error (FLEtracker) with cheap repetitions. FLE further contains the localization error in the imaging data (FLEimage), sampling of which in general is expensive and possibly biased. Finding the best techniques for estimating FLEimage is crucial for the applicability of the TRE prediction methods.