The effect of image quality on the identification of cephalometric landmarks.

The effect of rare-earth phosphor intensifying screens on diagnostic image quality was examined. Five observers were asked to identify ten landmarks on each of fifteen cephalometric images having varying screen-film-kvp combinations. The most sensitive screens were found to significantly affect diagnostic image quality and thereby the reliability of landmarks identification. This finding was, however, only established for those landmarks having the lowest standard deviations and the clinical significance is thus questionable. There would appear to be other more important factors than physical image quality involved in the reliability of landmark identification. High intensifying screens are, therefore, recommended for use in cephalometric analyses since they help to reduce patient dose and do not appear to sacrifice diagnostic image quality to the extent that the reliability of cephalometric measurements is significantly affected.