Cavouras D, Kandarakis I, Prassopoulos P, Kanellopoulos E, Nomicos C D, Panayiotakis G S
Department of Medical Instrumentation Technology, Technological Educational Institution of Athens, Greece.
Acta Radiol. 1999 Mar;40(2):211-6. doi: 10.3109/02841859909177741.
To propose an image quality index, the brightness-sharpness index (BSI), for assessing the quality of the image produced by phosphors of medical imaging detectors.
BSI was evaluated by experimental X-ray luminescence and modulation transfer function measurements. BSI was determined for a number of test phosphor screens prepared from Gd2O2S:Tb, La2O2S:Tb, and Y2O2S:Tb phosphor materials. The screens covered a wide range of coating thicknesses from 50 to 150 mg/cm2 and measurements were performed for X-ray tube voltages between 50 and 120 kVp.
Gd2O2S:Tb phosphor exhibited higher brightness and sharpness, as compared to the other phosphor materials, for all screens and X-ray tube voltages used. Best Gd2O2S:Tb performance was observed for thin screens and high tube voltages. La2O2S:Tb exhibited higher BSI values than Y2O2S:Tb for medium and high tube voltages.
Results showed that phosphor materials of high X-ray detection and X-ray-to-light conversion properties exhibit high BSI values indicating that BSI may provide a means of phosphor performance evaluation for imaging applications.
提出一种图像质量指标，即亮度锐度指数（BSI），用于评估医学成像探测器磷光体所产生图像的质量。
通过实验X射线发光和调制传递函数测量来评估BSI。对由Gd2O2S:Tb、La2O2S:Tb和Y2O2S:Tb磷光体材料制备的多个测试磷光屏测定BSI。这些屏的涂层厚度范围为50至150mg/cm2，并且在50至120kVp的X射线管电压下进行测量。
对于所有使用的屏和X射线管电压，与其他磷光体材料相比，Gd2O2S:Tb磷光体表现出更高的亮度和锐度。对于薄屏和高管电压，观察到Gd2O2S:Tb的最佳性能。对于中高管电压，La2O2S:Tb的BSI值高于Y2O2S:Tb。
结果表明，具有高X射线检测和X射线到光转换特性的磷光体材料表现出高BSI值，这表明BSI可为成像应用中的磷光体性能评估提供一种方法。
