Emission-transmission imaging system using single energy and dual energy transmission and radionuclide emission data

An emission-transmission imaging system comprising:

• a) an x-ray source for emitting an x-ray photon spectrum,
• b) an x-ray detector operated in the current-mode for detecting x-ray photons from the x-ray source,
• c) a radionuclide detector operated in the pulse-counting more for detecting photons corresponding to radionuclide emission,
• d) means for positioning the x-ray source facing the x-ray detector with an object containing a radionuclide between the x-ray source and the x-ray detector,
• e) means for maintaining relative positions of the x-ray detector and the radionuclide detector,
• f) an x-ray data acquisition system connected with the x-ray detector for receiving transmission signals from the x-ray detector,
• g) a radionuclide data acquisition system connected with the radionuclide detector for receiving emission signals from the radionuclide detector, representative of the radionuclide emission from the object,
• h) means for producing signals to maintain relative positions of x-ray and radionuclide data,
• i) computer means for receiving and processing the transmission signals and developing an attenuation map, and receiving and processing the radionuclide signals and producing image signals of distribution of a radionuclide of the object positioned between the x-ray source and the x-ray detector and radionuclide detector,
• j) a display system responsive to the image signals, and
• k) means for maintaining relative positions of said object with said x-ray detector and said radionuclide detector.

An emission-transmission imaging system comprising

• a) a radiation source for emitting a photon spectrum,
• b) detector means for selectively detecting photons corresponding to said photon spectrum and photons corresponding to radionuclide emission,
• c) means for positioning said radiation source facing said detector means with an object positionable therebetween, said object having a radionuclide distribution therein,
• d) data acquisition means connected with said detector means for receiving signals from said detector means representative of the detected photon spectrum photons and radionuclide signals representative of detected radionuclide emission signals,
• e) computer means for receiving photon spectrum signals and for receiving said radionuclide signals,
• f) first processing means for developing an attenuation map from said photon spectrum signals,
• g) second processing means for constructing objective functions from subsets of said radionuclide signals,
• h) algorithm means for iteratively seeking an extremum of said objective functions to calculate image estimates of said radionuclide distribution contained in said object, and
• i) means for altering said subsets of said radionuclide signals and said objective functions to incorporate subsequently measured signals.