Observer performance using monitors with different phosphors - an ROC study

The goal of the study was to compare observer performance using a P104 vs P45 CRT monitor for display of radiographic images. Different types of phosphor in a CRT monitor can affect the SNR, which in turn could affect the visibility of certain structures or lesions in an image. A series of portable CR chest images with subtle pulmonary nodules were presented to radiologists. They were instructed to search the images while their eye position was recorded. They reported on the presence or absence of a nodule, rated their confidence and reported on image quality. Physical measurements were also taken for both monitors (e.g., dynamic range, MTF, veiling glare). Observer performance was slightly better with the P45 than with the P104 monitor, although the difference was not statistically significant. Physical characterization of the two monitors also revealed advantages for the P45 monitor. P104 monitors are typically used in Asia while P45 monitors are typically used in the US. This study shows that choice of monitor phosphor may influence diagnostic and/or visual search performance and thus should be taken into account when selecting a monitor for clinical use.