Abstract
The intensity and distribution of the primary and scatter radiation that reaches the detectors in a Computed Tomography (CT) scanner has a direct impact in the clinical usability of the image reconstructed. The amount of radiation that reaches each detector depends on both the geometrical and material characteristics of the CT scanner, as well as the image acquisition parameters and patient characteristics. The purpose of this work is to determine the range of variation of total signal that reaches CT detectors in a computational simulation of a commercial CT scanner, using radiation transport Monte Carlo methods, as a study of the characteristics of a particular scanner configuration. The geometry was based on that of a commercially available CT scanner. The gadolinium oxysulfide detectors are separated by highly attenuating septa. In this exploratory study, two sets of monoenergetic beams were used, 45 keV and 80 keV. Scatter signal of the phantom is determined and the amount of primary signal that arrives to the detector is not evenly distributed on the module.