Affiliations: [a] Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| [b] Department of Physics and Astronomy, University of Rochester, Rochester, NY, USA
| [c] Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
Correspondence:
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Correspondence to: Jiangkun Liu, Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627, USA. E-mail: Jiangkun.liu@gmail.com.
Abstract: Grating-based differential phase contrast (DPC) imaging enables the use of a hospital-grade X-ray tube, but compromises the image quality due to insufficiently coherent illumination. In this research, a bench-top DPC cone beam CT (DPC-CBCT) was systematically evaluated and compared with the traditional attenuation-based CBCT in terms of contrast to noise ratio, noise property, and contrast resolution through phantom studies. In order to evaluate DPC-CBCT for soft tissue imaging, breast specimen and small animal studies were carried out. Phantom studies indicate that phase image has lower-frequency noise, higher CNR, and improved contrast resolution. However, phase image quality was degraded in soft tissue imaging due to coherence loss caused by small-angle scattering. Hence dark-field imaging was introduced to quantitatively investigate small-angle scattering caused by an object. Experimental results indicate that inhomogeneous objects affect phase contrast imaging, phase image is more sensitive to noise, and its performance is material dependent. Dark-field imaging could also be used to locate and reduce phase image noise and artifact caused by small-angle scattering.
