A theoretical model for calculation of the detective quantum efficiency ingranular scintillators

A theoretical model has been developed for calculating the detective quantu m efficiency (DQE) of scintillators, by taking into account the internal st ructure of granular scintillators often used in medical imaging detectors. Scintillators were considered to consist of N elementary thin layers contai ning spherical scintillating grains of equal size. Grains were assumed to b e regularly distributed within each thin layer, the thickness of the latter being equal to the grain diameter. Values of the X-ray absorption and X-ra y attenuation coefficients, of the intrinsic X-ray to light conversion effi ciency and of the optical scattering and absorption coefficients were used as input data to the model. Optical scattering and optical absorption coeff icients were determined by fitting the model to experimental luminescence d ata. The model was employed to calculate the detective quantum efficiency o f La2O2S:Tb, Y2O2S:Tb, Y2O2S:Eu, ZnSCdS:Ag, ZnSCdS:Au.,Cu scintillators. Re sults of the calculations were found close to values published in previous studies. (C) 2001 Elsevier Science Ltd. All rights reserved.