Screen optics effects on detective quantum efficiency in digital radiography: Zero-frequency effects
Screen optics effects on detective quantum efficiency in digital radiography: Zero-frequency effects
复制标题
DOI：
10.1118/1.2188082
复制
发表时间：
2006-05-01
期刊：
影响因子：
3.8
通讯作者：
Rowlands, J. A.
中科院分区：
文献类型：
--
作者：
Lubinsky, A. R.;Zhao, Wei;Rowlands, J. A.
间接平板成像器已被开发用于数字X射线摄影、荧光透视和乳房X射线摄影，并且现在已在临床上使用。由掺杂铊的柱状结构碘化铯（CsI）扩散器制成的屏已被广泛用于这些探测器中。本文的目的是研究屏幕光学的影响，例如，光逃逸效率与深度的关系，增益波动噪声，表示为Swank因子。我们的目标是获得有用的结果，在优化数字X射线摄影系统的屏幕。从结构化的CsI样品的实验测量被用来获得他们的屏幕光学特性，同样的方法也可以应用到粉末屏幕。CsI屏幕，所有的厚度相同，但具有不同的光学设计和制造技术，从Hamamatsu Photonics Corporation获得。在不同的X射线能量下测量了屏幕的脉冲高度谱（PHS）。一个理论模型的光逃逸效率和推导光逃逸效率与深度的实验PHS测量的方法被实施和应用到碘化铯屏幕。结果表明，CsI样品中的光逃逸效率基本上随深度线性变化，并且变化幅度相对较小，导致高Swank因子。(c)2006年美国医学物理学家协会。
Indirect flat panel imagers have been developed for digital radiography, fluoroscopy and mammography, and are now in clinical use. Screens made from columnar structured cesium iodide (CsI) scintillators doped with thallium have been used extensively in these detectors. The purpose of this article is to investigate the effect of screen optics, e.g., light escape efficiency versus depth, on gain fluctuation noise, expressed as the Swank factor. Our goal is to obtain results useful in optimizing screens for digital radiography systems. Experimental measurements from structured CsI samples were used to derive their screen optics properties, and the same methods can also be applied to powder screens. CsI screens, all of the same thickness but with different optical designs and manufacturing techniques, were obtained from Hamamatsu Photonics Corporation. The pulse height spectra (PHS) of the screens were measured at different x-ray energies. A theoretical model was developed for the light escape efficiency and a method for deriving light escape efficiency versus depth from experimental PHS measurements was implemented and applied to the CsI screens. The results showed that the light escape efficiency varies essentially linearly as a function of depth in the CsI samples, and that the magnitude of variation is relatively small, leading to a high Swank factor. (c) 2006 American Association of Physicists in Medicine.