High-precision evaluation of electromagnetic tracking

  • David KüglerEmail author
  • Henry Krumb
  • Judith Bredemann
  • Igor Stenin
  • Julia Kristin
  • Thomas Klenzner
  • Jörg Schipper
  • Robert Schmitt
  • Georgios Sakas
  • Anirban Mukhopadhyay
Original Article



Navigation in high-precision minimally invasive surgery (HP-MIS) demands high tracking accuracy in the absence of line of sight (LOS). Currently, no tracking technology can satisfy this requirement. Electromagnetic tracking (EMT) is the best tracking paradigm in the absence of LOS despite limited accuracy and robustness. Novel evaluation protocols are needed to ensure high-precision and robust EMT for navigation in HP-MIS.


We introduce a novel protocol for EMT measurement evaluation featuring a high-accuracy phantom based on LEGO\(^{\circledR }\), which is calibrated by a coordinate measuring machine to ensure accuracy. Our protocol includes relative sequential positions and an uncertainty estimation of positioning. We show effects on distortion compensation using a learned interpolation model.


Our high-precision protocol clarifies properties of errors and uncertainties of EMT for high-precision use cases. For EMT errors reaching clinically relevant 0.2 mm, our design is 5–10 times more accurate than previous protocols with 95% confidence margins of 0.02 mm. This high-precision protocol ensures the performance improvement in compensated EMT by 0.05 mm.


Our protocol improves the reliability of EMT evaluations because of significantly lower protocol-inherent uncertainties. To reduce patient risk in HP-MIS and to evaluate magnetic field distortion compensation, more high-accuracy protocols such as the one proposed here are required.


Electromagnetic tracking High-precision surgery Metallic distortion compensation Evaluation protocol LEGO\(^{\circledR }\)phantom 



This research was partially funded by the German Research Foundation Grant No. (FE 431/13-2).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Research involving human participants and/or animals

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed consent

This articles does not contain patient data.


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Copyright information

© CARS 2019

Authors and Affiliations

  • David Kügler
    • 1
    Email author
  • Henry Krumb
    • 1
  • Judith Bredemann
    • 2
  • Igor Stenin
    • 3
  • Julia Kristin
    • 3
  • Thomas Klenzner
    • 3
  • Jörg Schipper
    • 3
  • Robert Schmitt
    • 2
  • Georgios Sakas
    • 1
  • Anirban Mukhopadhyay
    • 1
  1. 1.Department of Computer ScienceTechnischer Universität DarmstadtDarmstadtGermany
  2. 2.WZL Aachen, RWTH AachenAachenGermany
  3. 3.ENT ClinicUniversity DüsseldorfDüsseldorfGermany

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