Comparisons of physical imaging properties among three kinds of imaging plates used in photostimulable phosphor systems for dental radiography.

The purpose of this study was to compare the physical imaging properties of three kinds of imaging plates (IPs) used with two photostimulable phosphor systems for dental radiography: HR-V, used with the Digora, BAS-SR, and ST-V, used with the DenOptix for intraoral radiography and panoramic radiography, respectively. Sensitivity to X-ray, gradient, modulation transfer function (MTF), noise power spectrum (NPS), noise-equivalent quanta (NEQ), and detective quantum efficiency (DQE) were compared. All imaging plates were read using the DenOptix scanner with inactive automatic range control (ARC). The scanning resolution was set at 300 dpi. Decay of image information by room light was also compared at inactive and active ARC settings. BAS-SR showed the lowest sensitivity, the lowest gradient, the highest MTF, and the highest NPS. ST-V showed the highest sensitivity, the highest gradient, the lowest MTF, and the lowest NPS. HR-V was the second best for all imaging properties examined in this study. NEQ and DQE of BAS-SR were lowest, and those of ST-V were highest at low spatial frequencies. However, BAS-SR showed relatively constant NEQ and DQE while those of ST-V decreased remarkably at high spatial frequencies. NEQ and DQE of HR-V were the second best at low spatial frequencies and the best at high spatial frequencies. Therefore, we concluded that HR-V has the best imaging properties for dental radiography among three kinds of IPs evaluated in this study. However, the light decay speed of image information with HR-V was remarkably faster than with BAS-SR. To adopt HR-V for a system with which IPs are treated in an ordinary room, the light decay should be taken into account.