A HIGH-RESOLUTION XRII-BASED QUANTITATIVE VOLUME CT SCANNER

A laboratory volume CT scanner has been developed, with high spatial r esolution in all three dimensions, which can be used for quantitative analysis of excised tissue samples in vitro. The system incorporates a n x-ray image intensifier, optically coupled to a time-delay integrati on (TDI) CCD to obtain low-noise and low-scatter projections of the sa mple volume. A water bath surrounds the sample to equalize the exposur e to the image intensifier, thereby reducing the dynamic range of the input signal. The scanner operates in two modes, producing either a si ngle, 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 a re discussed.