An electromagnetic “Tracker-in-Table” configuration for X-ray fluoroscopy and cone-beam CT-guided surgery
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A novel electromagnetic tracking configuration was characterized and implemented for image-guided surgery incorporating C-arm fluoroscopy and/or cone-beam CT (CBCT). The tracker employed a field generator (FG) with an open rectangular aperture and a frame enclosure with two essentially hollow sides, yielding a design that presents little or no X-ray attenuation across the C-arm orbit. The “Window” FG (WFG) was characterized in comparison with a conventional “Aurora” FG (AFG), and a configuration in which the WFG was incorporated directly into the operating table was investigated in preclinical phantom studies.
The geometric accuracy and field of view (FOV) of the WFG and AFG were evaluated in terms of target registration error (TRE) using an acrylic phantom on an (electromagnetic compatible) experimental bench. The WFG design was incorporated in a prototype operating table featuring a carbon fiber top beneath, which the FG could be translated for positioning under the patient. The X-ray compatibility was evaluated using a prototype mobile C-arm for fluoroscopy and CBCT in an anthropomorphic chest phantom. The susceptibility to EM field distortion associated with surgical tools (e.g., spine screws) and the C-arm itself was investigated in terms of TRE, and calibration methods were tested to provide robust image-world registration with minimal perturbation from the rotational C-arm.
The WFG demonstrated mean TRE of 1.28 ± 0.79 mm compared to 1.13 ± 0.72 mm for the AFG, with no statistically significant difference between the two (p = 0.32 and n = 250). The WFG exhibited a deeper field of view by ~10 cm providing an equivalent degree of geometric accuracy to a depth of z ~55 cm, compared to z ~45 cm for the AFG. Although the presence of a small number of spine screws did not degrade tracker accuracy, the mobile C-arm perturbed the electromagnetic field sufficiently to degrade TRE; however, a calibration method was identified to mitigate the effect. Specifically, the average calibration between posterior–anterior and lateral orientations of the C-arm was found to yield fairly robust registration for any C-arm pose with only a slight reduction in geometric accuracy (1.43 ± 0.31 mm in comparison with 1.28 ± 0.79 mm, p = 0.05). The WFG demonstrated reasonable X-ray compatibility, although the initial design of the window frame included suboptimal material and shape of the side bars that caused a level of streak artifacts in CBCT reconstructions. The streak artifacts were of sufficient magnitude to degrade soft-tissue visibility in CBCT but were negligible in the context of high-contrast imaging tasks (e.g., bone visualization).
The open frame of the WFG offers a potentially valuable configuration for electromagnetic trackers in image-guided surgery applications that are based on X-ray fluoroscopy and/or CBCT. The geometric accuracy and FOV are comparable to the conventional AFG and offers increased depth (z-direction) FOV. Incorporation directly within the operating table offers a streamlined implementation in which the tracker is in place but “invisible,” potentially simplifying tableside logistics, avoidance of the sterile field, and compatibility with X-ray imaging.
KeywordsSurgical navigation Intraoperative imaging CBCT Spine surgery Electromagnetic tracking Tracking accuracy Image quality
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- 2.Chan Y, Siewerdsen JH, Rafferty MA, Moseley DJ, Jaffray DA, Irish JC (2008) Cone-beam computed tomography on a mobile C-arm: novel intraoperative imaging technology for guidance of head and neck surgery. J Otolaryngol Head N 37(1): 81–90Google Scholar
- 3.Ishikawa Y, Kanemura T, Yoshida G, Ito Z, Muramoto A, Ohno S (2010) Clinical accuracy of three-dimensional fluoroscopy-based computer-assisted cervical pedicle screw placement: a retrospective comparative study of conventional versus computer-assisted cervical pedicle screw placement. J Neurosurg Spine 13(5): 606–611PubMedCrossRefGoogle Scholar
- 8.Schafer S, Nithananiathan S, Mirota DJ, Uneri A, Stayman JW, Zbijewski W, Schmidgunst C, Kleinszig G, Khanna AJ, Siewerdsen JH (2011) Mobile C-arm cone-beam CT for guidance of spine surgery: image quality, radiation dose, and integration with interventional guidance. Med Phys 38(8): 4563–4575PubMedCrossRefGoogle Scholar
- 9.Schafer S, Otake Y, Uneri A, Mirota DJ, Nithiananthan S, Stayman JW, Zbijewski W, Kleinszig G, Graumann R, Sussman M, Siewerdsen JH (2012) High-performance C-arm cone-beam CT guidance of thoracic surgery. In: Holmes DR III, Wong KH (eds) SPIE medical imaging. SPIE, San Diego, pp 83113–83161Google Scholar
- 16.Nafis C, Jensen V, von Jako R (2008) Method for evaluating compatibility of commercial electromagnetic (EM) microsensor tracking systems with surgical and imaging tables. In: Miga MI, Cleary KR (eds) SPIE, San Diego, pp 691815–691820Google Scholar
- 18.Schneider M, Stevens C (2007) Development and testing of a new magnetic-tracking device for image guidance. In: Cleary KR, Miga MI (eds) SPIE, San Diego, pp 65011–65090Google Scholar
- 19.Wilson E, Yaniv Z, Zhang H, Nafis C, Shen E, Shechter G, Wiles AD, Peters T, Lindisch D, Cleary K (2007) A hardware and software protocol for the evaluation of electromagnetic tracker accuracy in the clinical environment: a multi-center study. In: Cleary KR, Miga MI (eds) SPIE, San Diego, pp 65011–65092Google Scholar
- 25.Siewerdsen JH, Daly MJ, Chan H, Nithiananthan S, Hamming N, Brock KK, Irish JC (2009) High-performance intraoperative cone-beam CT on a mobile C-arm: an integrated system for guidance of head and neck surgery. In: Miga MI, Wong KH (eds) SPIE, Lake Buena Vista, pp 72610–72618Google Scholar
- 26.Siewerdsen JH, Shkumat NA, Dhanantwari AC, Williams DB, Richard S, Daly MJ, Paul NS, Moseley DJ, Jaffray DA, Yorkston J, Metter RV (2006) High-performance dual-energy imaging with a flat-panel detector: imaging physics from blackboard to benchtop to bedside. In: Michael JF, Jiang H (eds) Proceedings of SPIE physics of medical imaging. SPIE, p 61421EGoogle Scholar
- 28.Bachar G, Barker E, Nithiananthan S, Chan H, Daly MJ, Irish JC, Siewerdsen JH (2009) Three-dimensional tomosynthesis and cone-beam computed tomography: an experimental study for fast, low-dose intraoperative imaging technology for guidance of sinus and skull base surgery. Laryngoscope 119(3): 434–441PubMedCrossRefGoogle Scholar
- 32.Jaffray DA, Siewerdsen JH, Edmundson GK, Wong JW, Martinez AA (2002) Flat-panel cone-beam CT on a mobile isocentric C-arm for image-guided brachytherapy. In: Antonuk LE, Yaffe MJ (eds) SPIE, San Diego, pp 209–217Google Scholar