A comparison of x-ray detectors for mouse CT imaging.
A comparison of x-ray detectors for mouse CT imaging.
复制标题
用于小鼠 CT 成像的 X 射线探测器的比较。
DOI：
10.1088/0031-9155/49/23/004
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发表时间：
2004
影响因子：
3.5
通讯作者：
Cherry,SimonR
中科院分区：
文献类型：
--
作者：
Goertzen,AndrewL;Nagarkar,Vivek;Street,RobertA;Paulus,MichaelJ;Boone,JohnM;Cherry,SimonR
人们对使用计算机断层扫描（CT）在小鼠疾病模型中进行体内成像应用产生了极大的兴趣。大多数市售的鼠标X射线CT扫描仪利用电荷耦合器件（CCD）检测器，其经由光纤锥形耦合到荧光屏。然而，很少有研究来确定这是否是用于体内小鼠成像的特定任务的最佳检测器。为了研究这个问题，我们已经评估了四个探测器，包括非晶硒（a-Se）探测器，非晶硅（a-Si）探测器与硫氧化钆（GOS）屏幕，CCD与3：1光纤锥和GOS屏幕，和CCD与2：1光纤锥和GOS和铊掺杂碘化铯（CsI：Tl）屏幕。通过测量调制传递函数（MTF）、噪声功率谱（SNR）、探测量子效率（DQE）、多次曝光稳定性和重建CT图像中的噪声来评估探测器。a-Se探测器具有最好的MTF和最高的DQE（0 lp mm− 1时为0.6），但稳定性最差（2000帧曝光后降低45%）。a-Si探测器和采用3：1光纤的CCD都使用了GOS屏，它们的性能非常相似，在0 lp mm− 1下的DQE约为0.30。对于具有2：1光纤的CCD，CsI：Tl屏幕导致DQE比GOS屏幕提高近两倍（0 lp mm− 1时为0.4对0.24）。CCD都具有最好的稳定性，在多次曝光中像素值的变化小于1%。由于图像滞后的影响，a-Si探测器的像素值在多次曝光中增加了5%。尽管a-Se探测器的DQE较高，但用a-Si探测器采集的重建CT图像具有较低的噪声水平，这可能是由于荧光屏的模糊效应。
There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3: 1 fibre taper and a GOS screen, and a CCD with a 2: 1 fibre taper and both GOS and thallium-doped caesium iodide (CsI: Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise in reconstructed CT images. The a-Se detector had the best MTF and the highest DQE (0.6 at 0 lp mm− 1) but had the worst stability (45% reduction after 2000 exposure frames). The a-Si detector and the CCD with the 3: 1 fibre, both of which used the GOS screen, had very similar performance with a DQE of approximately 0.30 at 0 lp mm− 1. For the CCD with the 2: 1 fibre, the CsI: Tl screen resulted in a nearly two-fold improvement in DQE over the GOS screen (0.4 versus 0.24 at 0 lp mm− 1). The CCDs both had the best stability, with less than a 1% change in pixel values over multiple exposures. The pixel values of the a-Si detector increased 5% over multiple exposures due to the effects of image lag. Despite the higher DQE of the a-Se detector, the reconstructed CT images acquired with the a-Si detector had lower noise levels, likely due to the blurring effects from the phosphor screen.