# Open-source Tracked Ultrasound with Anser EMT

## TL;DR

This study demonstrates that an open-source electromagnetic tracker, Anser EMT, can effectively localize ultrasound probes in clinical settings with accuracy comparable to commercial systems, promoting transparency and customization in image-guided interventions.

## Contribution

First evaluation of the open-source Anser EMT for ultrasound probe tracking in clinical environments, showing comparable accuracy to commercial trackers.

## Key findings

- Anser EMT achieved a jitter of 0.1±0.1 mm and a position error of 1.1±0.7 mm.
- Rotation error of Anser EMT was 0.15±0.16°, lower than commercial trackers.
- Tracked US with Anser EMT is feasible for applications requiring 1-2 mm accuracy.

## Abstract

Image-guided Interventions (IGT) have shown a huge potential to improve medical procedures or even allow for new treatment options. Most ultrasound(US)-based IGT systems use electromagnetic (EM) tracking for localizing US probes and instruments. However, EM tracking is not always reliable in clinical settings because the EM field can be disturbed by medical equipment. So far, most researchers used and studied commercial EM trackers with their IGT systems which in turn limited the possibilities to customize the trackers in order minimize distortions and make the systems robust for clinical use. In light of current good scientific practice initiatives that increasingly request research to publish the source code corresponding to a paper, the aim of this work was to test the feasibility of using the open-source EM tracker Anser EMT for localizing US probes in a clinical US suite for the first time. The standardized protocol of Hummel et al. yielded a jitter of 0.1$\pm$0.1 mm and a position error of 1.1$\pm$0.7 mm, which is comparable to 0.1 mm and 1.0 mm of a commercial NDI Aurora system. The rotation error of Anser EMT was 0.15$\pm$0.16{\deg}, which is lower than at least 0.4{\deg} for the commercial tracker. We consider tracked US as feasible with Anser EMT if an accuracy of 1-2 mm is sufficient for a specific application.