Image Quality Determination of a Novel Low Energy X-ray Detector

The demand for adequate image quality with low radiation doses for patients has greatly increased. This is especially true in the case of position verification in radiotherapy which requires a high number of images per patient. This study presents a physical characterisation of a new clinical detector based on a thick layer of structured Thallium activated Cesium Iodide. We made a critical appraisal of its performance for the first time and determined its detective quantum efficiency (DQE) by acquiring the pre-sampling modulation transfer function and normalised noise power spectrum (NNPS). The investigation was conducted with the application of three x-ray beam qualities in compliance with the International Electrotechnical Commission (IEC 62220-1:2003) standard. The spatial resolution and NNPS results led to relatively high DQE values at all energies: DQEs (0.5) were 0.46 for 54kV, 0.52-0.56 for 74kV and 0.55-0.59 for 92kV.