Activating the interpixel septa of scintillator-photodiode detectors using an x-ray fluorescent reflector material

Scott S. Hsieh

doi:10.1117/12.3006477

1 April 2024 Activating the interpixel septa of scintillator-photodiode detectors using an x-ray fluorescent reflector material

Scott S. Hsieh

Author Affiliations +

Proceedings Volume 12925, Medical Imaging 2024: Physics of Medical Imaging; 129250C (2024) https://doi.org/10.1117/12.3006477
Event: SPIE Medical Imaging, 2024, San Diego, California, United States

Abstract

Energy-integrating detectors used in diagnostic CT consist of a scintillator that converts x-rays into visible light, and reflective septa that channel the produced visible light and reduce crosstalk between pixels. The reflective septa reduce the fill factor and dose efficiency of CT. It is desirable to reduce the size of the reflective septa, but for mechanical and optical reasons, such size reductions are not easily achieved. For this reason, we propose an alternative strategy: loading the septa with a high-Z material that can fluoresce with the incident x-rays and reemit characteristic x-rays, some of which would be absorbed in adjacent scintillator pixels. We model this approach using Monte Carlo simulations and show that approximately half of the area lost to reflective septa can be recovered with loading of Gd at a density of 1g/cc of Gd. We show that this can translate into higher resolution detectors: in the absence of an anti-scatter grid and assuming a reflective septa thickness of 0.1mm, dose efficiency can be better preserved even as the spatial resolution increases. When moving from a 1.0mm to 0.5mm pixel pitch, the expected reduction in dose efficiency is 26% without x-ray fluorescence loading. With x-ray fluorescence loading, the reduction in dose efficiency is only 4%.

Conference Presentation

(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.

Citation Download Citation

Scott S. Hsieh "Activating the interpixel septa of scintillator-photodiode detectors using an x-ray fluorescent reflector material", Proc. SPIE 12925, Medical Imaging 2024: Physics of Medical Imaging, 129250C (1 April 2024); https://doi.org/10.1117/12.3006477

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