Compton spectroscopy of clinical x-ray equipments by using a high-resolution Schottky CdTe detector

Abstract

The analysis of primary x-ray spectra is important for quality assurance (QA) and quality control (QC) of radiographic systems. The purpose of this study is to measure the diagnostic x-ray spectra under clinical conditions by using a high resolution Schottky CdTe detector. With high photon fluence rates under clinical conditions, the direct measurement of diagnostic x-ray spectra is so difficult because of the pile-up of the detector. 90 deg Compton spectroscopy is suitable in this case. The detector pile-up is not a problem with this measurement set-up. From the scattered spectrum one can then use an energy correction and the Klein-Nishina function to reconstruct the actual spectrum incident upon the scattering sample. The verification of whether our spectra measured by the Compton spectroscopy are accurate was accomplished by comparing exposures calculated from the reconstructed spectra to those measured with an ionization chamber. The small differences in exposures and half value layers obtained by both techniques suggest that Compton spectroscopy by using the high-resolution Schottky CdTe detector is suitable for measuring the diagnostic x-ray spectra and useful for QA and QC of clinical x-ray equipment.