Martin Bech, Presenter: Nothing to Disclose

Arne Tapfer, Abstract Co-Author: Nothing to Disclose

Astrid Velroyen, Abstract Co-Author: Nothing to Disclose

Franz Pfeiffer PhD, Abstract Co-Author: Nothing to Disclose

Bart Pauwels, Abstract Co-Author: Nothing to Disclose

Peter Bruyndonckx, Abstract Co-Author: Nothing to Disclose

Alexander Sasov, Abstract Co-Author: Nothing to Disclose

In recent years, phase-contrast x-ray imaging has been proven to yield superior image contrast compared to standard medical x-ray radiography and CT. The method of grating interferometer based phase-contrast imaging, also known as Talbot-Lau interferometry, can work with conventional x-ray sources, and can potentially be operated in a clinical environment. Here we show the first results obtained with a small-animal phase-contrast CT scanner developed in collaboration between the Technical University of Munich and SkyScan.

Due to the wave-optical effects of x-ray waves a minute angular refraction occurs when x-rays penetrate matter, similar to the refraction of optical light in a lens. These small angular refractions of x-rays can be measured with the aid of a grating interferometer. The novel phase-contrast CT scanner has a rotating gantry containing x-ray source, detector, and grating interferometer, implemented according to the scheme described in [1,2]. The total length of the interferometer is 45 cm (1 foot 6 inches) and the scanner is operated at an x-ray energy of 50 kVp. The bed of the scanner is optimized for mice, with a gantry opening of 35 mm (1.4 inches). From one single scan both phase-contrast and standard attenuation based tomography can be attained, providing an overall gain in image contrast. As standard CT relies on attenuation, and phase-contrast CT relies on refraction, two different physical quantities are reconstructed. These can be imaged in Hounsfield Units (HU) and Phase-Contrast Hounsfield Units (PC-HU). [1] F. Pfeiffer, T. Weitkamp, O. Bunk, and C. David, Nature Phys. 2 (2006) 258-261. [2] F. Pfeiffer, M. Bech, O. Bunk, P. Kraft, E.F. Eikenberry, C. Brönnimann, C. Grünzweig, and C. David, Nature Mat. 7, (2008) 134-137.

We will present the first imaging results obtained with the phase-contrast CT scanner, and demonstrate the complementary nature of the obtained phase-contrast and attenuation based images.

The scanner presented here is the first phase-contrast CT scanner with a rotating gantry, allowing for live animal studies, and is considered to be a major step towards clinical phase-contrast CT scanners.

Improved gray level contrast in CT images can greatly enhance the chances of successful diagnosis. In particular soft tissue regions will gain contrast with phase-contrast CT.

Bech, M, Tapfer, A, Velroyen, A, Pfeiffer, F, Pauwels, B, Bruyndonckx, P, Sasov, A, First Results from a Preclinical Phase-contrast Small Animal CT Scanner.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014977.html