Emission-transmission imaging system using single energy and dual energy transmission and radionuclide emission data
First Claim
1. An emission-transmission imaging system comprisinga) an x-ray source for emitting a low energy x-ray spectrum and a high energy x-ray spectrum,b) detector means for simultaneously and selectively detecting photons corresponding to said low energy x-ray spectrum and said high energy x-ray spectrum and photons corresponding to radionuclide emission,c) means for positioning said x-ray source facing said detector means with an object positionable therebetween, said object having a radionuclide therein,d) data acquisition means connected with said detector means for receiving signals from said detector means representative of detected low energy x-ray spectrum photons, high energy x-ray spectrum photons, and radionuclide emission photons,e) computer means for receiving and processing said signals and producing image signals of distribution of a radionuclide in said object based on emission photon data as corrected for material-specific attenuation derived from dual energy x-ray transmission data, andf) display means responsive to said image signals.
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Abstract
Radionuclide emission imaging is improved by correcting emission transmission data for attenuation along calculated path lengths and through calculated basis material. Single or dual energy projector data can be simultaneously obtained with radionuclide emission data to improve localization of radionuclide uptake. Dual energy x-ray projection techniques are used to calculate the path lengths and basis material (bone, tissue, fat). The radionuclide emission data and the transmitted x-ray data are simultaneously obtained using an energy selective photon detector whereby problems of misregistration are overcome. The dual-energy x-ray projection data are utilized to determine material-specific properties and are recombined into an effectively monoenergetic image, eliminating inaccuracies in material property estimation due to beam hardening. Use of a single instrument for simultaneous data collection also reduces technician time and floor space in a hospital.
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Citations
15 Claims
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1. An emission-transmission imaging system comprising
a) an x-ray source for emitting a low energy x-ray spectrum and a high energy x-ray spectrum, b) detector means for simultaneously and selectively detecting photons corresponding to said low energy x-ray spectrum and said high energy x-ray spectrum and photons corresponding to radionuclide emission, c) means for positioning said x-ray source facing said detector means with an object positionable therebetween, said object having a radionuclide therein, d) data acquisition means connected with said detector means for receiving signals from said detector means representative of detected low energy x-ray spectrum photons, high energy x-ray spectrum photons, and radionuclide emission photons, e) computer means for receiving and processing said signals and producing image signals of distribution of a radionuclide in said object based on emission photon data as corrected for material-specific attenuation derived from dual energy x-ray transmission data, and f) display means responsive to said image signals.
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8. A method of providing an improved radionuclide emission image comprising the steps of
providing a multiple energy x-ray source, providing detector means for simultaneously and selectively detecting photons corresponding to multiple energies from said x-ray source and photons from radionuclide emission, positioning a body having a radionuclide therein between said source and said detector means, simultaneously detecting photons from said x-ray source and from said radionuclide and generating signals indicative thereof, determining path lengths for basic materials for photons from radionuclide emission based on data from detected photons from said x-ray source, correcting radionuclide emission data based on attenuation thereof through said path lengths, for said basis materials, and displaying a radionuclide emission image based on the corrected radionuclide data.
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13. In radionuclide emission imaging, a method of correcting radionuclide emission data for an improved image comprising the steps of
simultaneously and selectively obtaining radionuclide emission data from a body and multiple energy x-ray transmission data from x rays passed through said body, determining basis material path lengths from said multiple energy x-ray transmission data, and correcting said radionuclide emission data based on attenuation of radionuclide emission along said basis material path lengths.
Specification