Optical Determination of the Cross Talk of CT Detection Systems

One of the most crucial properties of a CT scanner is its spatial resolution. The cross talk is one of the main parameters to influence this property. In this study we use an optical system to characterize CT detectors and photodiode arrays which are employed in such detectors. The PDA response is measured at each pixel as a function of X, Z, and the location within the array, for photodiode arrays made by several different manufacturers. In addition, the contributions due to the optical cross talk through the optical glue and due to the light penetrating the separators between the scintillator pixels are studied. The overall cross-talk results obtained are then compared to the actual cross talk measured on the CT scanner, yielding valuable information at an early stage of the scanner development.