Method and apparatus for performing multi-energy (including dual energy) computed tomography (ct) imaging

A system for providing a first energy measurement associated with a first X-ray energy range produced by a polychromatic X-ray tube, and a second energy measurement associated with a second X-ray energy range produced by the same polychromatic X-ray tube, wherein the second X-ray energy range is different from the first X-ray energy range, the system comprising:

• a filtered detector for detecting X-rays produced by the polychromatic X-ray tube across the first X-ray energy range and providing an output, wherein the output of the filtered detector comprises the first energy measurement;
• an unfiltered detector for detecting X-rays produced by the polychromatic X-ray tube across the full X-ray energy range of the polychromatic X-ray tube and providing an output;
• and
• a processor for determining the second energy measurement, wherein the second energy measurement is the difference between the output of the unfiltered detector and the output of the filtered detector.

A method for providing a first energy measurement associated with a first X-ray energy range produced by a polychromatic X-ray tube, and a second energy measurement associated with a second X-ray energy range produced by the same polychromatic X-ray tube, wherein the second X-ray energy range is different from the first X-ray energy range, the method comprising:

• providing a system for providing a first energy measurement associated with a first X-ray energy range produced by a polychromatic X-ray tube, and a second energy measurement associated with a second X-ray energy range produced by the same polychromatic X-ray tube, wherein the second X-ray energy range is different from the first X-ray energy range:
• a filtered detector for detecting X-rays produced by the polychromatic X-ray tube across the first X-ray energy range and providing an output, wherein the output of the filtered detector comprises the first energy measurement;
• an unfiltered detector for detecting X-rays produced by the polychromatic X-ray tube across the full X-ray energy range of the polychromatic X-ray tube and providing an output;
• and
• a processor for determining the second energy measurement, wherein the second energy measurement is the difference between the output of the unfiltered detector and the output of the filtered detector;
• using the polychromatic X-ray tube to cause the full X-ray energy range of the polychromatic X-ray tube to be received by the filtered detector and the unfiltered detector;
• and
• using the filtered detector to determine the first energy measurement, and using the processor to determine the second energy measurement.