Collier B D, Palmer D W, Knobel J, Isitman A T, Hellman R S, Zielonka J S
Radiology. 1984 May;151(2):495-7. doi: 10.1148/radiology.151.2.6231657.
By raising the lower threshold of the Tc-99m energy window, rejection of scattered photons can be made more efficient. Unfortunately, with most gamma cameras significant nonuniformities are produced when the window is changed to an asymmetric setting. Recently introduced designs with gain stabilization of the photomultiplier tubes and improved energy correction maintain field uniformity even for an asymmetric window. To assess the impact of an asymmetric energy window on clinical images, 33 Tc-99m-MDP scintigrams of the lumbar spine were taken with symmetrical (126-154 keV) and asymmetric windows (135-154 keV). Bone:soft tissue ratios improved with the asymmetric window, and the resulting images were preferred by the physicians questioned.
通过提高锝-99m能窗的下限，可以更有效地排除散射光子。遗憾的是，对于大多数γ相机而言，当窗设置改为非对称设置时会产生显著的不均匀性。最近推出的具有光电倍增管增益稳定和改进能量校正功能的设计，即使对于非对称窗也能保持视野均匀性。为了评估非对称能量窗对临床图像的影响，用对称窗（126 - 154 keV）和非对称窗（135 - 154 keV）采集了33例腰椎的锝-99m-亚甲基二膦酸盐骨闪烁图。使用非对称窗时骨与软组织的比值有所改善，参与调查的医生更青睐由此得到的图像。
