A HIGH-RESOLUTION XRII-BASED QUANTITATIVE VOLUME CT SCANNER

A laboratory volume CT scanner has been developed, with high spatial resolution in all three dimensions, which can be used for quantitative analysis of excised tissue samples in vitro. The system incorporates an x-ray image intensifier, optically coupled to a time-delay integration (TDI) CCD to obtain low-noise and low-scatter projections of the sample volume. A water bath surrounds the sample to equalize the exposure to the image intensifier, thereby reducing the dynamic range of the input signal. The scanner operates in two modes, producing either a single, transverse image through the sample or a three-dimensional image of the sample volume. Spatial resolution is adjustable over the range of 1.2 to 2.8 mm-1. System response is linear over the range -1000 to 3 500 Houndsfield units (HU), with an average precision of +/-80 HU. The precision of geometric measurements in the transverse plane allows circumference measurements to within +/-0.1 mm. Finally, applications of this technique of nondestructive analysis in biomedical research are discussed.