Date: Sep 18, 2018 Source: Spie (
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We have demonstrated a high resolution (10 micron) X-ray scintillator plate as part of an indirect X-ray detection system. Scintillator plates are typically integrated with a 2-dimensional array of photodiodes based upon amorphous Si. This paper describes an alternative digital capture system that leverages low cost CCD/CMOS cameras. Our detector has a broad set of potential applications, however the initial target application is mammography. Full-field mammography mandates an imaging area of 180mm x 240mm or larger. Very large CCD/CMOS sensors have recently been developed for high resolution cameras, such as the 250-pixel Canon camera which has sensor dimensions of 202mm x 205mm, and could conceivably be matched to our high-resolution scintillator plate without any intervening optics for magnification. However, such large format CCD/CMOS sensors have limited availability because of low production yields and high cost considerations. On the other hand, small form (36mm x 24mm) and medium format (44mm x 33mm) CCD/CMOS-based photodiodes have become widely available at low cost due to their applications in the large markets of mobile devices and consumer cameras. We have therefore developed a simple optical scheme for utilizing four small or medium format CCD/CMOS cameras to capture a larger, high-resolution image. Current systems employed in screening mammography resolve tissue features of 75-100 microns. Suspicious features found during preliminary mammographic screenings are further investigated during diagnostic mammographic tests which use a high-resolution detector that is focused over the suspicious lesion. Typically, an area less than 100mm x 80mm, the current maximum size of our high-resolution scintillation plate, is interrogated. We show that diagnostic mammography, over an area of 100mm x 80mm, could be performed using our system with a feature resolution down to 7 microns.
