Patel Tushita, Klanian Kelly, Gong Zongyi, Williams Mark B
Department of Physics, University of Virginia, Charlottesville, Virginia, USA.
Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.
Breast Imaging (2012). 2012 Jul;7361:80-87. doi: 10.1007/978-3-642-31271-7_11.
The spatial frequency dependent detective quantum efficiency (DQE) of a CsI-CMOS x-ray detector was measured in two operating modes: a high dynamic range (HDR) mode and a high sensitivity (HS) mode. DQE calculations were performed using the IEC-62220-1-2 Standard. For detector entrance air kerma values between ~7 µGy and 60 µGy the DQE is similar in either HDR mode or HS mode, with a value of ~0.7 at low frequency and ~ 0.15 - 0.20 at the Nyquist frequency f = 6.7 mm. In HDR mode the DQE remains virtually constant for operation with K values between ~7 µGy and 119 µGy but decreases for K levels below ~ 7 µGy. In HS mode the DQE is approximately constant over the full range of entrance air kerma tested between 1.7 µGy and 60 µGy but kerma values above ~75 µGy produce hard saturation. Quantum limited operation in HS mode for entrance kerma as small as 1.7 µGy makes it possible to use a large number of low dose views to improve angular sampling and decrease acquisition time.
在两种操作模式下测量了碘化铯互补金属氧化物半导体（CsI-CMOS）X射线探测器的空间频率相关探测量子效率（DQE）：高动态范围（HDR）模式和高灵敏度（HS）模式。使用IEC-62220-1-2标准进行DQE计算。对于探测器入口空气比释动能值在约7μGy至60μGy之间，在HDR模式或HS模式下DQE相似，在低频时约为0.7，在奈奎斯特频率f = 6.7mm时约为0.15 - 0.20。在HDR模式下，对于K值在约7μGy至119μGy之间的操作，DQE几乎保持恒定，但对于K值低于约7μGy时会降低。在HS模式下，在1.7μGy至60μGy之间测试的整个入口空气比释动能范围内，DQE大致恒定，但比释动能值高于约75μGy时会产生硬饱和。对于低至1.7μGy的入口比释动能，HS模式下的量子极限操作使得可以使用大量低剂量视图来改善角度采样并减少采集时间。
