206 results about "X ray spectra" patented technology

Method of and system for adaptive scatter correction in the absence of scatter detectors in multi-energy computed tomography are provided, wherein input projection data acquired using at least two x-ray spectra for scanned objects may include a set of low energy projections and a set of high energy projections; wherein a low-pass filter of variable size is provided; the method comprises estimating the size of the low-pass filter; computing amounts of scatter; and correcting both sets of projections for scatter. The estimation of low-pass filter size comprises thresholding high energy projections into binary projections; filtering the binary projections; finding the maximum of the filtered binary projections; calculating the low-pass filter size from the found maximum. The computation of amounts of scatter comprises exponentiating input projections; low-pass filtering the exponentiated projections with the estimated filter size; computing the amounts of scatter from the filtered projections.

An X-ray spectrometer which uses at least one curved analyzing crystal and which provides improved wavelength resolution of characteristic X-rays used for analysis and improved ratio of characteristic X-rays to background intensity by using only effective diffractive regions of the analyzing crystal. X-ray blocking plates upstand from an end of a crystal support member supporting the analyzing crystal in the direction of angular dispersion of the crystal toward the inside of a Rowland circle. Incident X-rays going from the point X-ray source toward the crystal and X-rays diffracted by the crystal toward an X-ray detector are partially blocked by the X-ray blocking plates. The shielded regions vary according to the incident angle θ of the incident X-rays. Optimum or nearly optimum effective regions of the surface of the crystal can be used at all times.

This invention relates to an optically coupled digital radiography method and apparatus for simultaneously obtaining two distinct images of the same subject, each of which represents a different x-ray energy spectrum. The two images may be combined in various ways such that anatomical features may be separated from one another to provide a clearer view of those features or of underlying structures. The two different images are obtained using a pair of scintillators separated by an x-ray filter that attenuates part of the x-ray spectrum of an x-ray exposure such that the first and second scintillators receive a different energy spectrum of the same x-ray exposure. Alternatively, the two different images can be obtained without a filter and with two scintillators made of different fluorescing materials that react differently to the same x-ray exposure.