Floyd C E, Chotas H G, Dobbins J T, Ravin C E
Duke University Medical Center, Durham, North Carolina 27710.
Med Phys. 1990 May-Jun;17(3):454-9. doi: 10.1118/1.596569.
We have evaluated a photostimulable phosphor x-ray imaging system [Philips Computed Radiography (PCR) system] for use in quantification of x-ray exposure in diagnostic radiography. An exponential function was fitted to data yielding quantitative x-ray exposure values as a function of digital pixel values. We investigated several factors that affect the accuracy of exposure measurement using the PCR including repeatability, background noise as a function of time delay between plate erasure and use, sensitivity variation between different plates, nonuniformity of sensitivity within a plate, decay of the latent image between time of exposure and readout (observed as a change in sensitivity), and the accuracy with which the (exponential) calibration function yields exposure values as a function of digital pixel values. The calibration was performed over the exposure range from 5.1 X 10(-9) to 2.0 X 10(-5) C/kg (0.02-75 mR). The accuracy of exposure measurements made with a single imaging plate is between 1.6% and 4.2%. If measurements from several plates are involved, the uncertainty in the final measurement will be between 5% and 5.9%.
我们评估了一种用于诊断放射成像中X射线曝光量定量的光激励荧光体X射线成像系统[飞利浦计算机放射成像（PCR）系统]。将一个指数函数拟合到数据上，得出作为数字像素值函数的定量X射线曝光值。我们研究了几个影响使用PCR进行曝光测量准确性的因素，包括重复性、作为板擦除和使用之间时间延迟函数的背景噪声、不同板之间的灵敏度变化、板内灵敏度的不均匀性、曝光时间和读出时间之间潜像的衰减（表现为灵敏度的变化），以及（指数）校准函数得出作为数字像素值函数的曝光值的准确性。校准在5.1×10⁻⁹至2.0×10⁻⁵C/kg（0.02 - 75 mR）的曝光范围内进行。使用单个成像板进行曝光测量的准确性在1.6%至4.2%之间。如果涉及多个板的测量，最终测量的不确定性将在5%至5.9%之间。
