Accuracy assessment of wireless transponder tracking in the operating room environment
To evaluate the applicability of the Calypso® wireless transponder tracking system (Varian Medical Systems Inc., USA) for real-time tumor motion tracking during surgical procedures on tumors in non-rigid target areas. An accuracy assessment was performed for an extended electromagnetic field of view (FoV) of 27.5 × 27.5 × 22.5 cm (which included the standard FoV of 14 × 14 × 19 cm) in which 5DOF wireless Beacon® transponders can be tracked.
Using a custom-made measurement setup, we assessed single transponder relative accuracy, absolute accuracy and jitter throughout the extended FoV at 1440 locations interspaced with 2.5 cm in each orthogonal direction. The NDI Polaris Spectra optical tracking system (OTS) was used as a reference. Measurements were taken in a room without surrounding distorting factors and repeated in an operating room (OR). In the OR, the influence of a carbon fiber and regular stainless steel OR tabletop was investigated.
The calibration of the OTS and transponder system resulted in an average root-mean-square error (RMSE) vector of 0.03 cm. For both the standard and extended FoV, all accuracy measures were dependent on transponder to tracking array (TA) distances and the absolute accuracy was also dependent on TA to OR tabletop distances. This latter influence was reproducible, and after calibrating this, the residual error was below 0.1 cm RMSE within the entire standard FoV. Within the extended FoV, this residual RMSE did not exceed 0.1 cm for transponder to TA distances up to 25 cm.
This study shows that transponder tracking is promising for accurate tumor tracking in the operating room. This applies when using the standard FoV, but also when using the extended FoV up to 25 cm above the TA, substantially increasing flexibility.
KeywordsAccuracy assessment Electromagnetic tracking Surgical navigation Wireless tracking Surgical oncology Abdominal surgery
We would like to thank Ton Vlasveld for his help in fabricating the measurement setup and Professor Jan-Jakob Sonke for his insightful input. We would like to thank Koningin Wilhelmina Fonds - Alpe d’HuZes (NKI 2014-6596) for their funding.
This study was funded by KWF-Alpe d’HuZes (NKI 2014-6596)
Compliance with ethical standards
Conflict of interest
The Netherlands Cancer Institute that facilitated this research has a research agreement with Varian Medical Systems. Varian was not involved in the design or execution of the study.
Human and animal rights
This article does not contain any studies with human participants or animals performed by any of the authors.
- 10.Sugimoto M, Yasuda H, Koda K, Suzuki M, Yamazaki M, Tezuka T, Kosugi C, Higuchi R, Watayo Y, Yagawa Y, Uemura S, Tsuchiya H, Azuma T (2010) Image overlay navigation by markerless surface registration in gastrointestinal, hepatobiliary and pancreatic surgery. J Hepatobiliary Pancreat Sci 17:629–636CrossRefGoogle Scholar
- 17.Wagner M, Gondan M, Zollner C, Wunscher JJ, Nickel F, Albala L, Groch A, Suwelack S, Speidel S, Maier-Hein L, Muller-Stich BP, Kenngott HG (2016) Electromagnetic organ tracking allows for real-time compensation of tissue shift in image-guided laparoscopic rectal surgery: results of a phantom study. Surg Endosc 30:495–503CrossRefGoogle Scholar
- 19.Willoughby TR, Kupelian PA, Pouliot J, Shinohara K, Aubin M, Roach M 3rd, Skrumeda LL, Balter JM, Litzenberg DW, Hadley SW, Wei JT, Sandler HM (2006) Target localization and real-time tracking using the Calypso 4D localization system in patients with localized prostate cancer. Int J Radiat Oncol Biol Phys 65:528–534CrossRefGoogle Scholar
- 22.Sawant A, Smith RL, Venkat RB, Santanam L, Cho B, Poulsen P, Cattell H, Newell LJ, Parikh P, Keall PJ (2009) Toward submillimeter accuracy in the management of intrafraction motion: the integration of real-time internal position monitoring and multileaf collimator target tracking. Int J Radiat Oncol Biol Phys 74:575–582CrossRefGoogle Scholar
- 23.Kupelian P, Willoughby T, Mahadevan A, Djemil T, Weinstein G, Jani S, Enke C, Solberg T, Flores N, Liu D, Beyer D, Levine L (2007) Multi-institutional clinical experience with the Calypso system in localization and continuous, real-time monitoring of the prostate gland during external radiotherapy. Int J Radiat Oncol Biol Phys 67:1088–1098CrossRefGoogle Scholar
- 25.Nakamoto M, Ukimura O, Gill IS, Mahadevan A, Miki T, Hashizume M, Sato Y (2008) Realtime organ tracking for endoscopic augmented reality visualization using miniature wireless magnetic tracker. MIAR 5128:359–366Google Scholar
- 27.Nafis C, Jensen V, Von Jako R (2008) Method for evaluating compatibility of commercial electromagnetic (EM) microsensor tracking systems with surgical and imaging tables. Med Imaging 6918(691820):15Google Scholar
- 29.Wen J (2010) Electromagnetic tracking for medical imaging. All Theses and Dissertations (ETDs) Paper 469, Washington University, Saint LouisGoogle Scholar
- 34.Tukey JW (1977) Exploratory data analysis. Pearson, Don MillsGoogle Scholar
- 36.Nafis C, Jensen V, Beauregard L, Anderson P (2006) Method for estimating dynamic EM tracking accuracy of surgical navigation tools. Proc SPIE Int Soc Opt Eng 6141:152–167Google Scholar