Ke Li MS, Presenter: Nothing to Disclose

Stephen T. Brunner BS, Abstract Co-Author: Nothing to Disclose

Yongshuai Ge, Abstract Co-Author: Nothing to Disclose

John W. Garrett MS, Abstract Co-Author: Nothing to Disclose

Guang-Hong Chen PhD, Abstract Co-Author: Research funded, General Electric Company Research funded, Siemens AG Research funded, Varian Medical Systems, Inc Research funded, Hologic, Inc

The recently proposed method to achieve X-ray differential phase contrast CT (DPC-CT) imaging using a grating Talbot-Lau interferometer has not had success in achieving in vivo DPC-CT scans. A novel method is proposed to achieve DPC-CT imaging without grating interferometer and used for in vivo imaging.

A calibration phantom (12.7 cm diameter) containing several insertions with known electron density was scanned using a 64-slice Discovery CT 750HD scanner to obtain electron density imaging of the phantom. The same phantom was scanned using a tabletop DPC-CT data acquisition system with grating interferometer to obtain DPC-CT imaging. The DPC-CT image values were calibrated to generate the corresponding electron density imaging. The calibration coefficients (at the effective energy of 28 keV) obtained from the benchtop grating based DPC-CT system were used to calibrated the electron density obtained from the dual energy CT scan into the corresponding DPC-CT image values. In vivo canine and porcine studies were performed to generate DPC-CT images at 28 keV effective energy.

DPC-CT image values measured from grating based DPC-CT system and the proposed method are given as the following pairs: Polymethyl methacrylate (3.32e-7, 3.33e-7); Polytetrafluoroethylene (5.49e-7, 5.19e-7); Polyoxymethylene (3.94e-7, 3.91e-7); GAMMEX Adipose (2.72e-7, 2.74e-7); GAMMEX Liver (3.16e-7, 3.22e-7). Linear regression of the DPC-CT image values obtained from the two methods has a coefficient of determination of 0.998. The slope of the regression was used to calibrate the electron density imaging from animal experiments to generate DPC-CT imaging in vivo.

DPC-CT imaging can be achieved in vivo from a clinical dual energy CT scanner with high accuracy and at any target X-ray beam energy.

DPC-CT images generated from DECT may provide immediate new diagnostic information for soft tissues without the complication of modifying hardware. This may open up a new venue for cancer detection.

Li, K, Brunner, S, Ge, Y, Garrett, J, Chen, G, A Novel Implementation of X-ray Differential Phase Contrast CT Imaging without Talbot-Lau Interferometer: Principles and In Vivo Animal Studies.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044369.html