Recent developments in CMOS image detectors are changing the way digital imaging is performed for many applications. The replacement of charge coupled devices (CCD's), with CMOS detectors is a desirable paradigm shift that will depend on the ability to match the high performance characteristics of CCD's. Digital X-ray imaging applications (chest X-ray, mammography) would benefit greatly from this shift because CMOS detectors have the following inherent characteristics: Low operating power (5-10 times lower than CCD/processing electronics) Standard CMOS manufacturing process (CCD requires special manufacturing) On-chip integration of analog/digital processing functions (difficult with CCD) Low Cost(5-10 timed lower cost than CCD) The achievement of both low cost and low power is highly desirable for portable applications as well as situations where large, expensive X-ray imaging machines are not feasible (small hospitals and clinics, emergency medical vehicles, remote sites). Achieving this goal using commercially available components would allow rapid development of such digital X-ray systems as compared with the development difficulties incurred through specialized direct detectors and systems. The focus of this paper is to evaluate a CMOS image detector for medical X-ray applications and to demonstrate the results obtained from a prototype CMOS digital X-ray camera. Results from the images collected from this optically-coupled camera are presented for a particular lens, X-ray conversion screen, and demagnification factor. Further, an overview of the overall power consumption and cost of a multi-sensor CMOS mosaic compared to its CCD counterpart are also reported.
