Apparatus and method for a high-flux photon-counting spectral application-specific integrated circuit (ASIC) having a charge summing mode

An apparatus, comprising:

• an X-ray source to radiate X-rays;
• a radiation detector, including a plurality of detector elements, configured to detect the X-rays radiated from the X-ray source and generate projection data, the radiation detector including
• a first element of the plurality of detector elements, the first element being configured to generate a first electrical signal, a magnitude of the first electrical signal representing respective energies of the X-rays detected by the first element,
• a second element of the plurality of detector elements, the second element being configured to generate a second electrical signal, a magnitude of the second electrical signal representing respective energies of the X-rays detected by the second element,
• a summing circuit configured to sum the first electrical signal and the second electrical signal to generate a combined electrical signal,
• a first comparator configured to compare the magnitude of the first electrical signal with a plurality of thresholds to generate a first comparator signal,
• a second comparator configured to compare the magnitude of the second electrical signal with the plurality of thresholds to generate a second comparator signal,
• a third comparator configured to compare a magnitude of the combined electrical signal with the plurality of thresholds to generate a third comparator signal, and
• a counter configured to
• receive the first comparator signal, the second comparator signal, and the third comparator signal, and
• record, as projection data, the third comparator signal as representing the energy of an X-ray of the detected X-rays, when at least one of the first comparator signal and the second comparator signal indicates a partial-detection magnitude;
• and
• processing circuitry configured to reconstruct a tomographic image using the projection data.

A method, comprising:

• receiving a first electrical signal, a magnitude of the first electrical signal representing an energy of an X-ray detected by a first element of an X-ray detector;
• receiving a second electrical signal, a magnitude of the second electrical signal representing an energy of an X-ray detected by a second element of the X-ray detector;
• summing the first electrical signal and the second electrical signal to generate a combined electrical signal;
• comparing the magnitude of the first electrical signal with a plurality of thresholds to generate a first comparator signal;
• comparing the magnitude of the second electrical signal with the plurality of thresholds to generate a second comparator signal;
• comparing the magnitude of the combined electrical signal with the plurality of thresholds to generate a third comparator signal;
• recording the third comparator signal as representing one of the energy of the X-ray of detected by the first element of the X-ray detector and the energy of the X-ray of detected by the second element of the X-ray detector, when at least one of the first comparator signal and the second comparator signal indicates a partial-detection magnitude;
• and
• reconstructing an computed tomography image based on the recorded third comparator signal.