Performance and suitability assessment of a real-time 3D electromagnetic needle tracking system for interstitial brachytherapy

Abstract

PurposeAccurate insertion and overall needle positioning are key requirements for effective brachytherapy treatments. This work aims at demonstrating the accuracy performance and the suitability of the Aurora® V1 Planar Field Generator (PFG) electromagnetic tracking system (EMTS) for real-time treatment assistance in interstitial brachytherapy procedures.Material and methodsThe system's performance was characterized in two distinct studies. First, in an environment free of EM disturbance, the boundaries of the detection volume of the EMTS were characterized and a tracking error analysis was performed. Secondly, a distortion analysis was conducted as a means of assessing the tracking accuracy performance of the system in the presence of potential EM disturbance generated by the proximity of standard brachytherapy components.ResultsThe tracking accuracy experiments showed that positional errors were typically 2 ± 1 mm in a zone restricted to the first 30 cm of the detection volume. However, at the edges of the detection volume, sensor position errors of up to 16 mm were recorded. On the other hand, orientation errors remained low at ± 2° for most of the measurements. The EM distortion analysis showed that the presence of typical brachytherapy components in vicinity of the EMTS had little influence on tracking accuracy. Position errors of less than 1 mm were recorded with all components except with a metallic arm support, which induced a mean absolute error of approximately 1.4 mm when located 10 cm away from the needle sensor.ConclusionsThe Aurora® V1 PFG EMTS possesses a great potential for real-time treatment assistance in general interstitial brachytherapy. In view of our experimental results, we however recommend that the needle axis remains as parallel as possible to the generator surface during treatment and that the tracking zone be restricted to the first 30 cm from the generator surface.

Technical Note: Identification of an optimal electromagnetic sensor for in vivo electromagnetic‐tracked scintillation dosimeter for HDR brachytherapy

“…The errors at different areas in the detection volume are similar to those that Boutaleb et al. presented …”

“…Figure shows that for the optimal usage distance as defined by Boutaleb et al . corresponding to Figs.…”

“…Four measurements were taken for each angle. The support is the same than the one used in Boutaleb et al . The uncertainty on the needle hole angle is .…”

“…Four measurements were taken for each angle. The support is the same than the one used in Boutaleb et al 14 The uncertainty on the needle hole angle is AE1 . Intermediate angles were obtained by raising one end of the acrylic support at known heights.…”

Technical Note: On EM reconstruction of a multi channel shielded applicator for cervical cancer brachytherapy: A feasibility study.

“…However, according to the literature, EMT tracking accuracy is sensitive to conductive metal which causes distorsions in the magnetic field. 12,13 In this technical note, a proof-of-concept is presented for the reconstruction of the individual channels of a shielded tandem applicator prototype. The purpose of this work was to show the feasibility of EMT for multichannel shielded applicator automated reconstruction.…”