Self-calibration of cone-beam CT geometry using 3D-2D image registration: Development and application to tasked-based imaging with a Robotic C-arm

S. Ouadah, J. W. Stayman, G. Gang, A. Uneri, T. Ehtiati, J. H. Siewerdsen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Purpose: Robotic C-arm systems are capable of general noncircular orbits whose trajectories can be driven by the particular imaging task. However obtaining accurate calibrations for reconstruction in such geometries can be a challenging problem. This work proposes a method to perform a unique geometric calibration of an arbitrary C-arm orbit by registering 2D projections to a previously acquired 3D image to determine the transformation parameters representing the system geometry. Methods: Experiments involved a cone-beam CT (CBCT) bench system, a robotic C-arm, and three phantoms. A robust 3D-2D registration process was used to compute the 9 degree of freedom (DOF) transformation between each projection and an existing 3D image by maximizing normalized gradient information with a digitally reconstructed radiograph (DRR) of the 3D volume. The quality of the resulting "self-calibration" was evaluated in terms of the agreement with an established calibration method using a BB phantom as well as image quality in the resulting CBCT reconstruction. Results: The self-calibration yielded CBCT images without significant difference in spatial resolution from the standard ("true") calibration methods (p-value >0.05 for all three phantoms), and the differences between CBCT images reconstructed using the "self" and "true" calibration methods were on the order of 10-3 mm-1. Maximum error in magnification was 3.2%, and back-projection ray placement was within 0.5 mm. Conclusion: The proposed geometric "self" calibration provides a means for 3D imaging on general noncircular orbits in CBCT systems for which a geometric calibration is either not available or not reproducible. The method forms the basis of advanced "task-based" 3D imaging methods now in development for robotic C-arms.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2015
Subtitle of host publicationImage-Guided Procedures, Robotic Interventions, and Modeling
EditorsRobert J. Webster, Ziv R. Yaniv
PublisherSPIE
ISBN (Electronic)9781628415056
DOIs
StatePublished - 2015
EventMedical Imaging 2015: Image-Guided Procedures, Robotic Interventions, and Modeling - Orlando, United States
Duration: Feb 22 2015Feb 24 2015

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume9415
ISSN (Print)1605-7422

Other

OtherMedical Imaging 2015: Image-Guided Procedures, Robotic Interventions, and Modeling
Country/TerritoryUnited States
CityOrlando
Period2/22/152/24/15

Keywords

  • Cone-beam CT
  • Image-guided interventions
  • Imaging task
  • Task-based imaging

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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