Comparisons between different technologies and collation of data will help refine acceptance thresholds and contribute to optimising dose and image quality. SNR was affected by the selection of acquisition protocol. Signal-to-noise ratios (SNRs) were calculated on a number of systems where pixel values were available. In order to assess the AEC performance, exit doses were also measured while varying phantom thickness. Dose was measured using a standard phantom as a basic means of comparing systems. As such, AEC is a key parameter for CR and DR. One consequence of moving from film screen to digital technologies is that the dynamic range of digital detectors is much wider, and increased exposures are no longer evident from changes in image quality. As part of this work, suggested reference values are provided to calculate the TO20 image quality factor. Subjective tests include the use of the Leeds TO20. The chief limitation in performing these tests was that not all systems provided ready access to pixel values. The protocols for detector assessment cover a broad range of tests and in general detectors (whether DR or CR) performed satisfactorily. Image quality assessment was based on detector assessment protocols and includes pixel value measures as well as subjective assessment using Leeds Test Objects. The patient is simulated using a range of thicknesses of tissue equivalent material. Particular attention is paid to the performance of the systems under automatic exposure control (AEC). Six different manufacturers are included. In this paper, the performance of a range of CR and DR systems is compared. Both IPEM and KCARE have recently published quality assurance and acceptance testing guidelines for DR. Computed radiography (CR) and digital radiography (DR) are replacing traditional film screen radiography as hospitals move towards digital imaging and picture archiving and communication systems (PACS).
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