Electromagnetic tracking

Intra-Op vision Endoscope Opti- cal/electromagnetic tracking device CT, CBCT, MRl, US... 

In this section we will discuss three of the more common methods used to collect human movement data electrogoniometers, electromagnetic tracking devices, and optoelectronic measuring systems. Of these distinctly different measuring tools, optoelectronic systems are the most common registration method, and therefore most of this section will focus on video-based motion analysis. 

Future advances include the automation of registration, which could further streamline clinical translation of such technologies. Miniaturization of internalized sensors for electromagnetic tracking of needles and ablation probes will have the ability to transform image-guided needle-based procedures by providing real-time multimodality feedback. 

Note that the majority of modern image-guided systems utilize optical tracking. Electromagnetic tracking systems are also sometimes utilized however, these systems typically have lower accuracy than optical systems. 

Milne, A. D. et al. "Acciu-acy of an electromagnetic tracking device A study of the optimal operating range and metal interference." Journal cf Biomechanics 29.6 (19%) p>p. 791-793. 

The motion of the needle tip was measured experimentally and compared with predictions of the analytical model. The tip motion is measured with a magnetic position sensor (miniBIRD model 80 from Ascension Technology). This electromagnetic tracking system measures the three positions and three orientations of a small sensor (1.3 mm in diameter, 6.5 mm in length) with RMS accuracies of 1.4 mm and 0.5°. The sensor is small compared to the manipulator and does not affect its performance. 

Zhang H, Banovac F, White A, Qeary K. (2006) Freehand 3D ultrasound calibration using an electromagnetically tracked needle. Proceedings of SPIE Medical Imaging Symposium, 2006, pp 775-783. 

C.L. Koerhuis, J.C. Winters, F.C. van der Helm, A.L. Hof. (2003) Neck mobility measurement by means of the Flock of Birds electromagnetic tracking system. Clin Biomech (Bristol, Avon) 18(1) 14-8. 

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