Assessment and comparison of target registration accuracy in surgical instrument tracking technologies

Abstract

Image guided surgery systems aim to support surgeons by providing reliable pre-operative and intra-operative imaging of the patient combined with the corresponding tracked instrument location. The image guidance is based on a combination of medical images, such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Ultrasonography (US), and surgical instrument tracking. For this reason, tracking systems are of great importance as they determine location and orientation of the equipment used by surgeons. Assessment of the accuracy of these tracking systems is hence of the utmost importance to determine how much error is introduced in image guided surgery only due to tracking inaccuracy. Thus, this study aimed to compare in a surgical Operating Room (OR) accuracy of the two most used tracking systems, Optical Tracking (OT) and Electromagnetic Tracking (EMT), in terms of Target Registration Error (TRE) assessment at multiple distances from the target position. Results of the experiments show that optical tracking performs more accurately in tracking the instrument tip than electromagnetic tracking in the experimental conditions. This was tested using a phantom designed for accuracy measurement in a wide variety of positions and orientations. Nevertheless, EMT remains a viable option for flexible instruments, due to its reliability in tracking without the need for line of sight.

Mixed reality as a novel tool for diagnostic and surgical navigation in orthopaedics

“…Overall, considering all the error sources [12]: optical tracking systems introduce approximately around 1.5-2 mm of error [7], hand-eye calibration could also introduce approximately 1-2 mm of error, pivot calibration introduced 0.8 mm, registration, camera and OTS localisation calibrations, IPD calibration, the accuracy of the navigation tool presents promising results for diagnostic assessment, but not as of yet for surgical procedures (where an accuracy inferior to five millimetres is generally acceptable [2]). The errors due to user inaccuracy or physical correspondent positions [11] may be reduced through better visualisation capabilities in HoloLens 2.…”

“…The use of the instrument tracking technologies allows the surgeon/clinician to visualise dynamic updates of the location and orientation of the femoral bone, and, for patients with hip pathologies, tracking allows the surgeon to see and understand the pathological hip-femoral head impingement untethered and within a large measurement volume (as opposed to other solutions that allow up to a maximum of 20 cm [5]). The study evaluates the accuracy in tracking a location at the tip of an instrument in holographic space of the navigation tool through two different phantom studies: the first experiment evaluates the accuracy through a custombuilt optical verification phantom, designed to fit American Society for Testing and Materials (ASTM ) standard F2554-10 for accuracy evaluation (more information in [7]). The second experiment evaluates the accuracy of the navigation tool in a more clinical scenario, using a whole-body CT patient phantom (PBU-50 Kyoto Kagaku Co. ), which is a full patient-body sized anthropomorphic phantom with movable and detachable joints, built with synthetic adult-sized bones.…”

“…The measure of accuracy for the navigation tool, evaluated throughout these studies, was the difference between the position of the optically tracked tool tip (with an offset from the tip, to remove bias due to a physical counterpart of the tool tip) and the target position of the phantom, after the user has moved its holographic equivalent into the target the phantom target position. This error allows to include not only visualisation errors inherent to MR (which are evaluated in [5,11]) but also the introduction of optical tracking inaccuracy and hand-eye calibration errors [7].…”

“…The first experiment was performed on a custom-built validation phantom based on the optical assessment standard ASTM F2554-10 [7]. The phantom presents a total of 28 titanium targets with a divot hole with a diameter of one millimetre on six different orientation planes (as shown in Fig.…”

Influence of sampling accuracy on augmented reality for laparoscopic image-guided surgery

“…Instrument tracking technologies are used in IGS to provide reliable information regarding position and orientation of surgical instruments. Moreover, tracking technologies are also used for registration tasks [4]. This study's field of application of IGS is Liver Laparoscopic Resection Surgery (LLRS).…”