@article{Ma2024,

title = {Fully automatic online geometric calibration for non-circular cone-beam CT orbits using fiducials with unknown placement},

author = {Yiqun Ma and Tess Reynolds and Tina Ehtiati and Clifford Weiss and Kelvin Hong and Nick Theodore and Grace Gang and J. Webster Stayman},

url = {https://pubmed.ncbi.nlm.nih.gov/38573172/

https://aapm.onlinelibrary.wiley.com/doi/10.1002/mp.17041},

doi = {10.1002/mp.17041},

year  = {2024},

date = {2024-05-01},

urldate = {2024-05-01},

journal = {Medical Physics},

volume = {51},

issue = {5},

pages = {3245-3264},

keywords = {Customized Acquisition, Geometric Calibration},

pubstate = {published},

tppubtype = {article}

}

@article{Ouadah2016,

title = {Self-calibration of cone-beam CT geometry using 3D-2D image registration.},

author = {Sarah Ouadah and J. Webster Stayman and Grace Gang and Tina Ehtiati and Jeffrey H. Siewerdsen },

url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC4948745},

doi = {10.1088/0031-9155/61/7/2613},

issn = {1361-6560},

year  = {2016},

date = {2016-04-01},

journal = {Physics in medicine and biology},

volume = {61},

number = {7},

pages = {2613--32},

abstract = {Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM-e.g. on the CBCT bench},

keywords = {CBCT, Customized Acquisition, Geometric Calibration, Image Registration},

pubstate = {published},

tppubtype = {article}

}