the advent of dual-modality pet/ct imaging has revolutionized the practice of clinical oncology, cardiology and neurology by improving lesions localization and the possibility of accurate quantitative analysis. in addition, the use of ct images for ct-based attenuation correction (ctac) allows to decrease the overall scanning time and to create a noise-free attenuation map (μmap). the near simu...

For a micro-Computed Tomography (Micro-CT) system, the microfocus X-ray tube is an essential component because the spatial resolution of CT images, in theory, is mainly determined by the size and stability of the X-ray focal spot of the microfocus X-ray tube. However, many factors, including voltage fluctuations, mechanical vibrations, and temperature changes, can cause the size and the stabili...

This study explores the potential of different X-ray computed tomography (X-ray CT) set-ups for the discrimination of soil mineral matter, soil organic matter (OM) and the pore phase. Different X-ray sources, detectors and filtering methods were investigated. Use of a low-energy detector as well as a Cu-filter decreased the potential for phase segmentation in X-ray CT images of an artificial sa...

Reliable, noninvasive imaging modalities to characterize plaque components are clinically desirable for detecting unstable coronary plaques, which cause acute coronary syndrome. Although recent clinical developments in computed tomography (CT) have enabled the visualization of luminal narrowing and calcified plaques in coronary arteries, the identification of noncalcified plaque components rema...

We investigated performance of ultrafast (30 fs –200 fs) laser-based x-ray source as an alternative to a microfocal x-ray tube used in micro-CT systems. A number of solid targets including Ge, Mo, Rh, Ag, Sn, Ba, La, Nd with matching filters was used. We optimized conditions for x-rays generation, measured x-ray spectra and obtained images of small animals using various characteristic x-ray lin...

BACKGROUND There are differences in the reference diagnostic levels for the computed tomography (CT) of the chest as cited in different literature sources. The doses are expressed either in weighted CT dose index (CTDIVOL) used to express the dose per slice, dose-length product (DLP), and effective dose (E). The purpose of this study was to assess the radiation dose used in Low Dose Computer To...

The soft-X ray range, between 1-10 nm wavelength, is highly interesting for X-ray microscopy. Taking advantage of it requires, however, to operate a high resolution instrument at a variable wavelength. We describe here an image converter X-ray microscope which is based on secondary pharoemission. This instrument is now developped at the Institut dlOptique (Orsay); it will be installed near ACO ...