23 March 2016 Improving detector spatial resolution using pixelated scintillators with a barrier rib structure
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Abstract
Indirect conversion flat panel detectors (FPDs) based on amorphous silicon (a-Si) technology are widely used in digital X-ray imaging. In such FPDs a scintillator layer is used for converting X-rays into visible light photons. However, the lateral spread of these photons inside the scintillator layer reduces spatial resolution of the FPD. In this study, FPDs incorporating pixelated scintillators with a barrier rib structure were developed to limit lateral spread of light photons thereby improving spatial resolution. For the pixelated scintillator, a two-dimensional barrier rib structure was first manufactured on a substrate layer, coated with reflective materials, and filled to the rim with the scintillating material of gadolinium oxysulfide (GOS). Several scintillator samples were fabricated, with pitch size varying from 160 to 280 μm and rib height from 200 to 280 μm. The samples were directly coupled to an a-Si flat panel photodiode array with a pitch of 200 μm to convert optical photons to electronic signals. With the pixelated scintillator, the detector modulation transfer function was shown to improve significantly (by 94% at 2 cycle/mm) compared to a detector using an unstructured GOS layer. However, the prototype does show lower sensitivity due to the decrease in scintillator fill factor. The preliminary results demonstrated the feasibility of using the barrier-rib structure to improve the spatial resolution of FPDs. Such an improvement would greatly benefit nondestructive testing applications where the spatial resolution is the most important parameter. Further investigation will focus on improving the detector sensitivity and exploring its medical applications.
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Langechuan Liu, Langechuan Liu, Minghui Lu, Minghui Lu, Wanqing Cao, Wanqing Cao, Luke Peng, Luke Peng, Arthur Chen, Arthur Chen, } "Improving detector spatial resolution using pixelated scintillators with a barrier rib structure", Proc. SPIE 9783, Medical Imaging 2016: Physics of Medical Imaging, 978315 (23 March 2016); doi: 10.1117/12.2216330; https://doi.org/10.1117/12.2216330
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