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Proceedings Paper

High-performance C-arm cone-beam CT guidance of thoracic surgery
Author(s): Sebastian Schafer; Yoshito Otake; Ali Uneri; Daniel J. Mirota; Sajendra Nithiananthan; J. Webster Stayman; Wojciech Zbijewski; Gerhard Kleinszig; Rainer Graumann; Marc Sussman; Jeffrey H. Siewerdsen
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Paper Abstract

Localizing sub-palpable nodules in minimally invasive video-assisted thoracic surgery (VATS) presents a significant challenge. To overcome inherent problems of preoperative nodule tagging using CT fluoroscopic guidance, an intraoperative C-arm cone-beam CT (CBCT) image-guidance system has been developed for direct localization of subpalpable tumors in the OR, including real-time tracking of surgical tools (including thoracoscope), and video-CBCT registration for augmentation of the thoracoscopic scene. Acquisition protocols for nodule visibility in the inflated and deflated lung were delineated in phantom and animal/cadaver studies. Motion compensated reconstruction was implemented to account for motion induced by the ventilated contralateral lung. Experience in CBCT-guided targeting of simulated lung nodules included phantoms, porcine models, and cadavers. Phantom studies defined low-dose acquisition protocols providing contrast-to-noise ratio sufficient for lung nodule visualization, confirmed in porcine specimens with simulated nodules (3-6mm diameter PE spheres, ~100-150HU contrast, 2.1mGy). Nodule visibility in CBCT of the collapsed lung, with reduced contrast according to air volume retention, was more challenging, but initial studies confirmed visibility using scan protocols at slightly increased dose (~4.6-11.1mGy). Motion compensated reconstruction employing a 4D deformation map in the backprojection process reduced artifacts associated with motion blur. Augmentation of thoracoscopic video with renderings of the target and critical structures (e.g., pulmonary artery) showed geometric accuracy consistent with camera calibration and the tracking system (2.4mm registration error). Initial results suggest a potentially valuable role for CBCT guidance in VATS, improving precision in minimally invasive, lungconserving surgeries, avoid critical structures, obviate the burdens of preoperative localization, and improve patient safety.

Paper Details

Date Published: 17 February 2012
PDF: 13 pages
Proc. SPIE 8316, Medical Imaging 2012: Image-Guided Procedures, Robotic Interventions, and Modeling, 83161I (17 February 2012); doi: 10.1117/12.911811
Show Author Affiliations
Sebastian Schafer, The Johns Hopkins Univ. (United States)
Yoshito Otake, The Johns Hopkins Univ. (United States)
Ali Uneri, The Johns Hopkins Univ. (United States)
Daniel J. Mirota, The Johns Hopkins Univ. (United States)
Sajendra Nithiananthan, The Johns Hopkins Univ. (United States)
J. Webster Stayman, The Johns Hopkins Univ. (United States)
Wojciech Zbijewski, The Johns Hopkins Univ. (United States)
Gerhard Kleinszig, Siemens Healthcare (Germany)
Rainer Graumann, Siemens Healthcare (Germany)
Marc Sussman, Johns Hopkins Medical Institute (United States)
Jeffrey H. Siewerdsen, The Johns Hopkins Univ. (United States)

Published in SPIE Proceedings Vol. 8316:
Medical Imaging 2012: Image-Guided Procedures, Robotic Interventions, and Modeling
David R. Holmes III; Kenneth H. Wong, Editor(s)

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