Radiology Department, Leiden University Medical Centre, Leiden, The Netherlands.
Eur Radiol. 2010 Apr;20(4):958-66. doi: 10.1007/s00330-009-1617-x. Epub 2009 Sep 30.
To develop and validate software for facilitating observer studies on the effect of radiation exposure on the diagnostic value of computed tomography (CT).
A low dose simulator was developed which adds noise to the raw CT data. For validation two phantoms were used: a cylindrical test object and an anthropomorphic phantom. Images of both were acquired at different dose levels by changing the tube current of the acquisition (500 mA to 20 mA in five steps). Additionally, low dose simulations were performed from 500 mA downwards to 20 mA in the same steps. Noise was measured within the cylindrical test object and in the anthropomorphic phantom. Finally, noise power spectra (NPS) were measured in water.
The low dose simulator yielded similar image quality compared with actual low dose acquisitions. Mean difference in noise over all comparisons between actual and simulated images was 5.7 +/- 4.6% for the cylindrical test object and 3.3 +/- 2.6% for the anthropomorphic phantom. NPS measurements showed that the general shape and intensity are similar.
The developed low dose simulator creates images that accurately represent the image quality of acquisitions at lower dose levels and is suitable for application in clinical studies.
开发并验证一款软件，以辅助观察者研究辐射对计算机断层扫描（CT）诊断价值的影响。
开发了一款低剂量模拟器，它可以在原始 CT 数据中添加噪声。为了验证，使用了两个体模：一个圆柱形测试物体和一个人体模型。通过改变采集管电流（从 500mA 到 20mA 分五步变化），在不同剂量水平下获取了这两个体模的图像。此外，还从 500mA 以相同的步长模拟至 20mA 的低剂量。在圆柱形测试物体和人体模型内测量噪声。最后，在水中测量噪声功率谱（NPS）。
低剂量模拟器生成的图像质量与实际低剂量采集相似。在实际图像与模拟图像的所有比较中，噪声的平均差异在圆柱形测试物体中为 5.7%±4.6%，在人体模型中为 3.3%±2.6%。NPS 测量结果表明，形状和强度大致相似。
开发的低剂量模拟器可以创建准确反映低剂量采集图像质量的图像，适用于临床研究。
