A computer simulation method for low-dose CT images by use of real high-dose images: a phantom study
A computer simulation method for low-dose CT images by use of real high-dose images: a phantom study
复制标题
利用真实高剂量图像进行低剂量CT图像的计算机模拟方法：模型研究
DOI：
10.1007/s12194-015-0332-3
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发表时间：
2016
影响因子：
1.6
通讯作者：
Shiraishi J
中科院分区：
文献类型：
--
作者：
1.Takenaga T;Katsuragawa S;Goto M;Hatemuna M;Uchiyama Y;Shiraishi J
对低剂量CT图像的实际模拟有可能成为优化CT曝光剂量的有效手段。由于目前几位研究人员报道的方法仅限于特定的供应商平台，并且通常依赖于难以访问的原始正弦图数据，因此我们开发了一种新的计算机化方案，用于从真实的高剂量图像生成模拟低剂量CT图像，而不使用原始正弦图数据或特定体模。我们的低剂量CT模拟的计算机化方案是基于将模拟的噪声图像添加到通过滤波反投影算法重建的真实的高剂量CT图像。首先，从高剂量CT图像的正向投影生成正弦图。然后，从预定的噪声模型估计由于使用减少的曝光剂量而产生的附加噪声正弦图。最后，用预定的滤波器重建噪声CT图像，并将其添加到真实的高剂量CT图像中，生成模拟的低剂量CT图像。模拟低剂量图像的噪声功率谱和调制传递函数与真实低剂量图像非常接近。为了验证我们方法的可行性，我们将这种方法应用于临床病例，这些病例最初进行了高剂量检查，然后进行了低剂量CT检查。总之，我们提出的方法可以足够准确地从真实的高剂量CT图像模拟出低剂量CT图像，并可用于确定各种临床CT检查的最佳剂量设置。
Practical simulations of low-dose CT images have a possibility of being helpful means for optimization of the CT exposure dose. Because current methods reported by several researchers are limited to specific vendor platforms and generally rely on raw sinogram data that are difficult to access, we have developed a new computerized scheme for producing simulated low-dose CT images from real high-dose images without use of raw sinogram data or of a particular phantom. Our computerized scheme for low-dose CT simulation was based on the addition of a simulated noise image to a real high-dose CT image reconstructed by the filtered back-projection algorithm. First, a sinogram was generated from the forward projection of a high-dose CT image. Then, an additional noise sinogram resulting from use of a reduced exposure dose was estimated from a predetermined noise model. Finally, a noise CT image was reconstructed with a predetermined filter and was added to the real high-dose CT image to create a simulated low-dose CT image. The noise power spectrum and modulation transfer function of the simulated low-dose images were very close to those of the real low-dose images. In order to confirm the feasibility of our method, we applied this method to clinical cases which were examined with the high dose initially and then followed with a low-dose CT. In conclusion, our proposed method could simulate the low-dose CT images from their real high-dose images with sufficient accuracy and could be used for determining the optimal dose setting for various clinical CT examinations.