X-ray analysis apparatus
First Claim
1. A method of performing normalization in x-ray analysis comprisingscanning an object utilizing an x-ray beam in a plane,detecting through x-ray radiation with a linear array of detectors,translating said linear array of detectors in the plane of the beam so that each detector in said linear array of detectors moves a distance of at least two detector dimensions, and sampling the signal of said detectors repeatedly in the manner that each detector detects x-rays at the same pixel as a neighboring detector,comparing said gain of each detector with a gain of said neighboring detector for said same pixel, andadjusting said gain of each detector by a correction factor dependent upon said comparison.
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Abstract
X-ray analysis apparatus and related method including a bone densitometer apparatus, in which detectors are translatable in the plane of the fan beam for each scan line position to provide enhanced signal-to-noise ratio and resolution, and detector-to-detector normalization. In this motion, the detectors move relative to an x-ray source and an object or patient. Indexing or moving from one scan line position to the next involves relative movement between the object or patient, and the x-ray source and detectors, which are fixed in relationship to each other during this indexing.
98 Citations
26 Claims
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1. A method of performing normalization in x-ray analysis comprising
scanning an object utilizing an x-ray beam in a plane, detecting through x-ray radiation with a linear array of detectors, translating said linear array of detectors in the plane of the beam so that each detector in said linear array of detectors moves a distance of at least two detector dimensions, and sampling the signal of said detectors repeatedly in the manner that each detector detects x-rays at the same pixel as a neighboring detector, comparing said gain of each detector with a gain of said neighboring detector for said same pixel, and adjusting said gain of each detector by a correction factor dependent upon said comparison.
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5. An x-ray analysis apparatus comprising
an x-ray source means which generates and projects at least one x-ray beam of fan shape in a plane transverse to a desired direction of scan of an object, detector array means arranged on the opposite side of the object to detect x-rays to produce signals corresponding to the amount of x-rays transmitted through the object, said detector array means comprising a plurality of detector elements having a continually exposed sensitive region of predetermined dimension, said detector array means, together with and in fixed relation to said x-ray source means, being movable relative to the object in a scanning direction normal to the plane of the beam through a multiplicity of scan line positions, and said detector array means at each scan line position of said x-ray source means being movably driven in a set of selected equal increments relative to said x-ray source means and the object in a second direction in the plane of the beam, transverse to the scanning direction, a said increment having a length corresponding to a fraction of said predetermined continually exposed dimension of said sensitive region, means to produce, in correspondence with said set of selected equal increments, multiple samples of the signals from each said detector element of the detector array means at each scan line position of said x-ray source means during said movement of said detector array means in said second, transverse direction, and signal processing means responsive to signals from the detector array means corresponding to said multiple samples to produce an image of the object.
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18. An x-ray analysis apparatus comprising
an x-ray source means which generates and projects at least one x-ray beam of fan shape in a plane transverse to a desired direction of scan of an object, detector array means arranged on the opposite side of the object to detect x-rays to produce signals corresponding to the amount of x-rays transmitted through the object, said detector array means comprising a plurality of detector elements having a continually exposed sensitive region of predetermined dimension, said detector array means, together with and in fixed relation to said x-ray source means, being movable relative to the object in a scanning direction normal to the plane of the beam through a multiplicity of scan line positions, and said detector array means at each scan line position of said x-ray source means being movably driven in a set of selected equal increments relative to said x-ray source means and the object in a second direction in the plane of the beam, transverse to the scanning direction, the size and spacing of said detector elements and the size and number of said increments of movement causing each detector, at least at one of its positions in each scan line position, to overlie the same location on said object as does an adjacent detector element in at least one of its positions in said scan line position, means to produce, in correspondence with said set of selected equal increments, multiple samples of the signals from each said detector element of the detector array means at each scan line position of said x-ray source means during said movement of said detector array means in said second, transverse direction, and signal processing means responsive to signals from the detector array means corresponding to said multiple samples to produce an image of the object, the apparatus further comprising normalizing means for comparing the signal associated with each pair of adjacent detector elements for a particular location on the object as detected by at least one of said pair of detector elements with the signal associated with the same location on the object as detected by the other of said pair of detector elements and adjusting the response of one of said detector elements of each pair on the basis of said comparison.
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24. A bone densitometer apparatus for measuring the bone density of a patient comprising
x-ray source means comprising x-ray tube means, associated power supply, and collimator slit which generates and projects at least one x-ray beam in a fan beam shape, detector array means arranged on the opposite side of the patient to detect x-rays to produce signals corresponding to the amount of x-rays transmitted through the patient, said detector array means comprising a plurality of detector elements having a continually exposed sensitive region of predetermined dimension, said detector array means, together with and in fixed relation to said x-ray source means, being translatable in a scanning direction normal to the plane of the beam through a multiplicity of scan line positions, and said detector array means at each scan line position of said x-ray source means being translatable in a set of selected equal increments in a second direction in the plane of the beam, transverse to said scanning direction, a said increment having a length corresponding to a fraction of said predetermined continually exposed dimension of said sensitive region, means to produce, in correspondence with said set of selected equal increments, multiple samples of the signals from each said detector element of the detector array means at each scan line position of said x-ray source means during said movement of said detector array means in said second, transverse direction, and signal processing means responsive to signals from the detector array means corresponding to said multiple samples to produce an image of the bone density of the patient.
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26. A method of performing x-ray analysis on an object comprising:
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generating, from an x-ray source means, at least one x-ray beam of fan shape in a plane; exposing the object by passing said x-ray fan beam through it; detecting x-rays attenuated by the object utilizing a detector array means, said detector array means comprising a plurality of detector elements having a continually exposed sensitive region of predetermined dimension; translating said detectors and said beam together in fixed relation in a scanning direction normal to said plane of said x-ray fan beam through a number of scan line positions to perform a scan on the object; at each scan line position, translating said detectors, relative to said x-ray source means and the object, in a set of selected equal increments in a direction transverse to said scanning direction, a said increment having a length corresponding to a fraction of said predetermined continually exposed dimension of said sensitive region; producing, in correspondence with said set of selected equal increments, multiple samples of the signals from each said detector element of the detector array means at each scan line position of said x-ray source means during said movement of said detector array means in said transverse direction; and producing, by utilizing signal processing means responsive to signals from the detector array means corresponding to said multiple samples, an image of the object.
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Specification