Measurement of half-value layer in computed tomography scanners using luminescence of polyethersulfone resin by X-ray irradiation

In this study, a method for estimating the half-value layer (HVL) and effective energy (E_eff) by imaging the luminescence from a polyethersulfone (PES) resin with rotating irradiation of X-rays in a computed tomography scanner was developed. The luminescence of the PES resin was imaged using a charge-coupled device camera. The PES-HVL was determined from the luminance attenuation profile corresponding to the X-ray attenuation within the resin. The PES-HVLs for tube potentials of 80-135 kVp were converted into E_eff values and were compared to those of a conventional lead-covered case method. The E_eff obtained using the proposed luminescence imaging method agreed within ∼3.9% of that obtained using the conventional method. Moreover, dose simulations based on the X-ray spectrum calculated from the HVLs were performed using a poly(methyl methacrylate) phantom with a diameter of 16 cm. The simulated doses based on the luminescence imaging method agreed with the in-phantom dosimetry within ∼9%. (authors)