Acceptance testing and commissioning of Kodak Directview CR-850 digital radiography system

摘要

This Technical Paper describes Acceptance Testing and Commissioning of the Kodak DirectView CR-850 digital radiography system installed at the Royal Adelaide Hospital. The first of its type installed in Australia, the system is a "dry" image processor, for which no chemicals are required to develop images. Rather, latent radiographic images are stored on photostimulable phosphor screens, which are scanned and displayed by a reader unit. The image can be digitally processed and enhanced before it is forwarded to a storage device, printer or workstation display, thereby alleviating the need to re-expose patients to achieve satisfactory quality images. The phosphor screens are automatically erased, ready for re-use. Results are reported of tests carried out using the optional "Total Quality Tool" quality assurance package installed with the system. This package includes analysis and reporting software which provides for simple testing and reporting of many important characteristics of the system, such as field uniformity, aspect ratio, line and pixel positions, image and system noise, exposure response, scan linearity, modulation transfer function (MTF) and image artefacts. Acceptance Tests were performed for kV and MV exposures. Resolution for MV exposures was at least 0.8 l/mm, and measured phantom dimensions were within 1.05% of expected magnification. Reproducibility between cassettes was within 1.6%. The mean pixel values on the central axis were close to linear for MV exposures from 3 to 10 MU and reached saturation level at around 20 MU for 6 MV and around 30 MV for 23 MV beams. Noise levels were below 0.2%.