David A. Langan PhD, Abstract Co-Author: Employee, General Electric Company

Xiaoye Wu PhD, Abstract Co-Author: Employee, General Electric Company

Paul Licato MS, Presenter: Employee, General Electric Company

Naveen Chandra PhD, Abstract Co-Author: Employee, General Electric Company

Akihiko Nishide, Abstract Co-Author: Employee, General Electric Company

Uwe Wiedmann, Abstract Co-Author: Employee, General Electric Company

Yasuhiro Imai MS, Abstract Co-Author: Employee, General Electric Company

Dan Xu PhD, Abstract Co-Author: Employee, General Electric Company

Thomas M. Benson PhD, Abstract Co-Author: Employee, General Electric Company

Jed Pack, Abstract Co-Author: Employee, General Electric Company

et al, Abstract Co-Author: Nothing to Disclose

We developed a helical fast kV switching Dual Energy scan method on a High Definition CT system. The purpose of this study is to demonstrate the image quality benefits of dual energy scanning using a fast kV switching approach.  The fast kV Dual Energy system demonstrated the ability to acquire dual energy data with helical scanning at full 50 cm field-of-view. The purpose was to evaluate temporal registration, robustness of material differentiation, material sensitivity, and artifact improvement.  

A new High Definition CT system with fast detector and x-ray generator response times and the ability to over-sample in the detection system, was used to acquire interleaved helical data consisting of high- and low-kVp views in an interleaved fashion.  View-to-view fast kV switching can acquire interleaved 80 and 140kV scan data. Normally, X-ray tube voltage switching requires a few seconds. This data acquisition technique at 50cm FOV was performed using 80kVp and 140kVp target energies. The following capabilities were evaluated: - Dual energy helical images of a multi material phantom and a moving phantom at different frequencies. - Projection-based material decomposition. - Comparison with images generated using weighted subtraction methods.  

The helical fast kV dual energy scan method provides adequate energy separation for robust projection-based material decomposition and monochromatic imaging. The projection-based reconstruction algorithms provide more accurate results and beam-hardening reduction when compared to image-based weighted subtraction techniques. We confirmed that images acquired using the helical fast kV dual energy scanning technique demonstrate adequate image registration of moving objects. Monochromatic energy was selected to optimize contrast-to-noise and compared to static kVp and weighted subtraction methods. Artifact mitigation and contrast

The Helical Fast kV scanning technique was evaluated for image quality and artifact reduction. It provides a robust method of dual energy data acquisition and processing with benefits for beam hardening reduction, reduced misregistration artifacts and patient motion, material separation and quantification, and contrast-to-noise optimization.

 The disclosed method enables helical, full field of view, dkVp CT scanning and is robust to patient motion.

Langan, D, Wu, X, Licato, P, Chandra, N, Nishide, A, Wiedmann, U, Imai, Y, Xu, D, Benson, T, Pack, J, et al, , Development of a Helical Fast kV Switching Dual Energy Scan Method.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6021937.html