Amiaz Altman PhD, Presenter: Nothing to Disclose

Galit Naveh PhD, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to present results of a unique CT configuration that enables energy-spectrum information in a single scan, without switching the tube voltage and without passive filtering. Results demonstrate a significant substance separation, and tissue resolution with potential for new applications and Molecular Imaging.

Rearrangement of a conventional CT detection system that enables both energy windowing and an infinitely expandable array along patient-coverage axis is presented. The configuration consists of a unique geometrical positioning of main detection components, scintillator and photodiode arrays. The system enables spectral sorting of the detected X-rays into two energy windows or more, while retaining the sum of the windows as a conventional CT output. The new system enables the configuration of any number of detection rows (slices) along the patient, using conventional photodiode arrays, without the need for complicated technologies. The mean energies of the spectral windows are designed to optimize the separation of tissues required by different applications. CT simulations and experiments has been performed to verify tissues and substance separation for various applications. Specifically, a separation between calcification and contrast material for true vessel analysis in CTA and Cardiac CTA has been investigated. The possibility of detecting the presence of very small concentrations of iodine compounds has been also studied to evaluate the potential of this configuration for CT-based Molecular Imaging.

Results show a significant separation between calcification and contrast material for relative concentrations that have the same HU when scanned in a conventional CT manner. The signal difference between the two substances, when analyzed using two energy windows, is more than 10 times above the noise. Furthermore, a significant signal difference is shown between locations of very small Iodine concentration and soft tissue, indicating the potential for this method in Molecular Imaging.

A simple to implement spectral CT demonstrates a potential breakthrough, especially in CTA, cardiac applications, and in CT-based molecular imaging.

G.N.,A.A.: Authors work for company funding study (Philips)

Altman, A, Naveh, G, A Realization Method of Spectral CT for Resolving Different Tissues and Substance.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4407635.html