Dynamic, three-dimensional optical tracking of an ablative laser beam
Work-flow diagram of the image-guided surgery process. Creating the registration between physical space and image space (dotted box) is performed one time at the start of surgery. Orion traverses the loop to track the instrument and display its position in , updating the instrument position in real time.
(a) Custom-designed laser tracking handpiece and Northern Digital 24-IRED pen probe. (b) Diagram of double-helix configuration employed for IRED placement on surface of surgical handpiece. (c) Schematic demonstrating the six degrees of freedom in position and trajectory during instrument tracking.
(a) Schematic of multilevel ablation phantom with 60 target points (white circles), four fiducials (black circles), and a predefined right-handed Cartesian coordinate system. As depicted, the laser handpiece was consistently oriented during ablation tracking such that the laser beam axis was perpendicular to the plane of the phantom. (b) Defined geometry for angle measurement of the target registration error from the centroid positions of the true and ablated target points.
Distribution of target registration errors between 60 targets and their corresponding burn holes during beam focus tracking. (a) TRE histogram. (b) Relationship between fiducial registration error and target registration error during beam focus tracking. Each registration had four fiducials and six targets. (c) Two-dimensional TRE distribution indicating error magnitudes and angles (measured counter-clockwise from the positive -axis as outlined in Fig. 3), with five error populations deriving from different handpiece orientations employed during ablation tracking.
Principal component scores of the three-dimensional IRED positions within rigid body space of the laser handpiece: (a) Principal component scores versus IRED number for the individual helices. For display purposes, the PC2 and PC3 scores are shifted and , respectively; (b) PC1 versus PC2; (c) PC1 versus PC3; and (d) PC2 versus PC3. Filled IRED markers indicate the first IRED within a helix.
Effect of stray FEL energy on accuracy of tracking 24-IRED Northern Digital pen probe (1400 fiducials, 1050 targets).
Accuracy of tracking the 24-IRED laser handpiece with passive tip and a 24-IRED Northern Digital pen probe (3360 total fiducials, 2520 total targets).
Relative contributions of position and trajectory components to localization error of the instrument points of interest for the Northern Digital 24-IRED pen probe and the laser handpiece.
Relative contributions of the various elements of the experimental design to the overall laser focus tracking error. Each point population contained 100 three-dimensional points. Mean distances between the population centroids were calculated over every combination of two centroids.
Article metrics loading...
Full text loading...