Evaluation of a CMOS image detector for low-cost and power medical x-ray imaging applications

摘要

Abstract: Recent developments in CMOS image detectors arechanging the way digital imaging is performed for manyapplications. The replacement of charge coupled devices(CCDs), with CMOS detectors is a desirable paradigmshift that will depend on the ability to match the highperformance characteristics of CCDs. Digital X-rayimaging applications (chest X-ray, mammography) wouldbenefit greatly from this shift because CMOS detectorshave the following inherent characteristics: (1) Lowoperating power (5 - 10 times lower than CCD/processingelectronics). (2) Standard CMOS manufacturing process(CCD requires special manufacturing). (3) On-chipintegration of analog/digital processing functions(difficult with CCD). (4) Low Cost (5 - 10 times lowercost than CCD). The achievement of both low cost andlow power is highly desirable for portable applicationsas well as situations where large, expensive X-rayimaging machines are not feasible (small hospitals andclinics, emergency medical vehicles, remote sites).Achieving this goal using commercially availablecomponents would allow rapid development of suchdigital X-ray systems as compared with the developmentdifficulties incurred through specialized directdetectors and systems. The focus of this paper is toevaluate a CMOS image detector for medical X-rayapplications and to demonstrate the results obtainedfrom a prototype CMOS digital X-ray camera. Resultsfrom the images collected from this optically-coupledcamera are presented for a particular lens, X-rayconversion screen, and demagnification factor. Further,an overview of the overall power consumption and costof a multi-sensor CMOS mosaic compared to its CCDcounterpart are also reported. !8