Experimental dual xenon detectors for quantitative CT and spectral artifact correction

A 41-channel xenon detector array has been built in our laboratory to be used in a fan-beam CT scanner. Each channel is split into a front and rear detector producing two signals for each ray through the patient. Since the front and rear detectors measure different photon energies of the x-ray spectra, dual energy information is obtained from a single CT scan. This information can be used to determine electron density and effective atomic number images of the patient and correct spectral artefacts. A 7.7-cm-diam plexiglas cylinder, filled with water and various plastics, was scanned. With this phantom, electron density was determined to an accuracy of 2% and effective atomic number to 4%. Details of the detector design and calibration are discussed and electron density, effective atomic number, and spectral artifact corrected images are presented.