Skip to main content

Anser EMT: the first open-source electromagnetic tracking platform for image-guided interventions



Electromagnetic tracking is the gold standard for instrument tracking and navigation in the clinical setting without line of sight. Whilst clinical platforms exist for interventional bronchoscopy and neurosurgical navigation, the limited flexibility and high costs of electromagnetic tracking (EMT) systems for research investigations mitigate against a better understanding of the technology’s characterisation and limitations. The Anser project provides an open-source implementation for EMT with particular application to image-guided interventions.


This work provides implementation schematics for our previously reported EMT system which relies on low-cost acquisition and demodulation techniques using both National Instruments and Arduino hardware alongside MATLAB support code. The system performance is objectively compared to other commercial tracking platforms using the Hummel assessment protocol.


Positional accuracy of 1.14 mm and angular rotation accuracy of \(0.04^{\circ }\) are reported. Like other EMT platforms, Anser is susceptible to tracking errors due to eddy current and ferromagnetic distortion. The system is compatible with commercially available EMT sensors as well as the Open Network Interface for image-guided therapy (OpenIGTLink) for easy communication with visualisation and medical imaging toolkits such as MITK and 3D Slicer.


By providing an open-source platform for research investigations, we believe that novel and collaborative approaches can overcome the limitations of current EMT technology.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9


  1. 1.

    Choi KY, Seo BR, Kim JH, Kim SH, Kim TS, Lee JK (2013) The usefulness of electromagnetic neuronavigation in the pediatric neuroendoscopic surgery. J Korean Neurosurg Soc 53(3):161–166

    Article  PubMed  PubMed Central  Google Scholar 

  2. 2.

    Cleary K, Peters TM (2010) Image-guided interventions. Annu Rev Biomed Eng 12:119–142

    CAS  Article  PubMed  Google Scholar 

  3. 3.

    Nardelli P, Jaeger A, OShea C, Cantillon-Murphy P, Kennedy MP (2016) Navigational bronchoscopy for early lung cancer: a road to therapy. Adv Therapy 33(4):580–596

    Article  Google Scholar 

  4. 4.

    Franz AM, Haidegger T, Birkfellner W, Cleary K, Peters TM, Maier-Hein L (2014) Electromagnetic tracking in medicine-a review of technology, validation, and applications. IEEE Trans Med Imaging 33(8):1702–1725

    Article  PubMed  Google Scholar 

  5. 5.

    Franz AM, März K, Hummel J, Birkfellner W, Bendl R (2012) Electromagnetic tracking for us-guided interventions: standardized assessment of a new compact field generator. Int J Comput Assist Radiol Surg 7(6):813–818

    CAS  Article  PubMed  Google Scholar 

  6. 6.

    Lugez E, Sadjadi H, Pichora DR, Ellis RE, Akl SG, Fichtinger G (2015) Electromagnetic tracking in surgical and interventional environments: usability study. Int J Comput Assist Radiol Surg 10(3):253–262

    Article  PubMed  Google Scholar 

  7. 7.

    Liu X, Plishker W, Zaki G, Kang S, Kane TD, Shekhar R (2016) On-demand calibration and evaluation for electromagnetically tracked laparoscope in augmented reality visualization. Int J Comput Assist Radiol Surg 11(6):1163–1171

  8. 8.

    Anser design repository. Accessed on 10/27/2016

  9. 9.

    Open source electromagentic trackers. Accessed on 10/27/2016

  10. 10. Accessed on 10/27/2016

  11. 11. Accessed on 10/27/2016

  12. 12.

    O’Donoghue K, Eustace D, Griffiths J, O’Shea M, Power T, Mansfield H, Cantillon-Murphy P (2014) Catheter position tracking system using planar magnetics and closed loop current control. IEEE Trans Magn 50(7):1–9

    Article  Google Scholar 

  13. 13.

    O’Donoghue K, Cantillon-Murphy P (2015) Planar magnetic shielding for use with electromagnetic tracking systems. IEEE Trans Magn 51(2):1–12

    Article  Google Scholar 

  14. 14.

    O’Donoghue K, Cantillon-Murphy P (2015) Low cost super-nyquist asynchronous demodulation for use in em tracking systems. IEEE Trans Instrum Meas 64(2):458–466

    Article  Google Scholar 

  15. 15.

    O’Donoghue K, Corvó A, Nardelli P, O’Shea C, Khan KA, Kennedy M, Cantillon-Murphy P (2014) Evaluation of a novel tracking system in a breathing lung model. In: 2014 36th annual international conference of the IEEE engineering in medicine and biology society, pp 4046–4049

  16. 16.

    Analog Devices. Low power, programmable, waveform generator. Accessed on 10/27/2016

  17. 17.

    Paul H, Winfield H (1980) The art of electronics. Cambridge University Press, Cambridge

  18. 18.

    Autodesk PCB Design. Accessed on 10/27/2016

  19. 19.

    O’Donoghue K (2014) Electromagnetic tracking and steering for catheter navigation. Ph.D. thesis, School of Engineering, University College Cork

  20. 20.

    Anton P, Eugene P (2003) 3-D magnetic tracking of a single subminiature coil with a large 2-D array of uniaxial transmitters. IEEE Trans Magn 39(5 II):3295–3297

    Google Scholar 

  21. 21.

    Cadsoft. Eagle pcb design. Accessed on 10/27/2016

  22. 22.

    Hopkins LW (1949) Development of a highly accurate synchronous demodulator. CRC Press, Boca Raton

    Google Scholar 

  23. 23.

    Sonntag CLW, Sprée M, Lomonova EA, Duarte JL, Vandenput AJA (2007) Accurate magnetic field intensity calculations for contactless energy transfer coils. In: Proceedings of the 16th international conference on the computation of electromagnetic fields, Achen, Germany, pp 1–4

  24. 24.

    Openigtlink: Open network interface for image-guided therapy. Accessed on 10/27/2016

  25. 25.

    The medical imaging interaction toolkit (mitk). Accessed on 10/27/2016

  26. 26.

    3dslicer. a multi-platform, free and open source software package for visualization and medical image computing. Accessed on 10/27/2016

  27. 27.

    Maier-Hein L, Franz AM, Birkfellner W, Hummel J, Gergel I, Wegner I, Meinzer HP (2012) Standardized assessment of new electromagnetic field generators in an interventional radiology setting. Med Phys 39(6):3424–3434

    CAS  Article  PubMed  Google Scholar 

  28. 28.

    Hummel JB, Bax MR, Figl ML, Kang Y, Maurer C, Birkfellner WW, Bergmann H, Shahidi R (2005) Design and application of an assessment protocol for electromagnetic tracking systems. Med Phys 32(7):2371–2379

    Article  Google Scholar 

  29. 29.

    Hummel J, Figl M, Birkfellner W, Shahidi R, Maurer CR Jr, Bergmann H (2006) Evaluation of a new electromagnetic tracking system using a standardized assessment protocol. Phys Med Biol 51(2):205–210

    Article  Google Scholar 

  30. 30.

    Much J (2008) Error classification and propagation for electromagnetic tracking. Master’s thesis, Tech. Univ. München, Munich, Germany, Tech. Univ. München, Munich, Germany

  31. 31.

    International Commission on Non-Ionizing Radiation Protection (2010) Guidelines for limiting exposure to time-varying electric and magnetic fields. Health Phys 99(6):818–836

    Google Scholar 

  32. 32.

    O’Donoghue K, Cantillon-Murphy P (2015) Low cost super-nyquist asynchronous demodulation for use in em tracking systems. IEEE Trans Instrum Meas 64(2):458–466

    Article  Google Scholar 

Download references


This work was supported by the Irish Health Research Board (POR/2012/31), Science Foundation Ireland (15/TIDA/2846). This work was also supported by the European Union through the ERC starting Grant COMBIOSCOPY under the New Horizon Framework Programme Grant Agreement ERC-2015-StG-37960. The authors would also like to acknowledge the German Cancer Research Center (DKFZ), Heidelberg, and the Institute of Image-Guided Surgery (IHU), Strasbourg, in supporting this work.

Author information



Corresponding author

Correspondence to Herman Alexander Jaeger.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

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.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Jaeger, H.A., Franz, A.M., O’Donoghue, K. et al. Anser EMT: the first open-source electromagnetic tracking platform for image-guided interventions. Int J CARS 12, 1059–1067 (2017).

Download citation


  • Electromagnetic tracking
  • Open source
  • Image guidance
  • Image-guided surgery
  • OpenIGTLink