ISSN 1004-4140
CN 11-3017/P

基于渐进式网络处理的低剂量Micro-CT成像方法

Low-dose Micro-CT Imaging Method Based on Progressive Network Processing

  • 摘要: 微米级计算机断层扫描(Micro-CT)的应用领域很广泛,在生物医学、材料科学等都有研究,而且最近几年的发展很迅速。Micro-CT图像常因辐射剂量的限制而出现噪声,所以开发一种合适的算法来抑制Micro-CT图像中噪声变得很重要。Micro-CT图像的噪声水平与扫描样本、扫描参数等参数有关,合适的噪声抑制算法应该在不同噪声水平下都有不错的性能。过去Micro-CT图像的噪声抑制算法主要是迭代重建算法,但迭代重建算法速度比较慢。深度学习方法作为近些年比较热门的图像处理方法,在临床低剂量CT图像处理上相比于传统方法效果更好、处理速度更快,有进一步在低剂量Micro-CT图像处理中应用的潜力。另外,生成对抗网络在保持图像细节上有着比卷积神经网络更好的效果,本文构建普通卷积神经网络与生成对抗网络,用于对比两者的性能差异。限制于放射源的功率,低噪声的Micro-CT数据难以获取,提出一种创新的扫描方式,可有效获取低噪声的Micro-CT数据,并对实验小鼠的进行了扫描。针对低剂量Micro-CT中较高的噪声,结合Micro-CT的成像原理,提出渐进式的低剂量Micro-CT图像处理方法,分别在解析重建前后对小鼠的Micro-CT图像进行两次处理。相比于只在断层图像上处理,渐进式方法对高噪声数据的处理效果更好。从客观指标与主观视觉效果上,分析和对比了渐进式方法与其他深度学习方法或迭代重建算法的差别。定量分析不同噪声水平下的Micro-CT图像的处理效果,分析生成对抗网络在渐进式Micro-CT图像处理中的优势与限制。渐进式Micro-CT图像处理方法生成的图像质量高、生成速度快、鲁棒性高、客观指标高,可以对进一步的高级应用如图像分割、图像三维可视化等提供帮助。

     

    Abstract: Micro-CT has a wide range of application fields, and has been studied in biomedicine and materials science, and has developed rapidly in recent years. Micro-CT images often suffer from noise due to radiation dose limitations, so it is important to develop an appropriate algorithm to suppress noise in Micro-CT images. The noise level of the Micro-CT image is related to the scanned samples, scanning parameters and other parameters. The noise suppression algorithm should have good performance under different noise levels. In the past, the noise suppression algorithm of Micro-CT images was mainly an iterative reconstruction algorithm, but the iterative reconstruction algorithm was relatively slow. As a popular image processing method in recent years, the deep learning method has better effect and faster processing speed than traditional methods in clinical low-dose CT image processing, and has the potential for further application in low-dose Micro-CT image processing. In addition, generative adversarial networks have better results than convolutional neural networks in maintaining image details. In this paper, ordinary convolutional neural networks and generative adversarial networks are designed to compare their performance differences. Limited to the power of the radioactive source, high-dose Micro-CT images are difficult to acquire. This paper has proposed an innovative scanning method that can effectively obtain low-noise Micro-CT data of mice. Due to high noise of low-dose Micro-CT, combined with the imaging principle of Micro-CT, a progressive low-dose Micro-CT image processing method was proposed, which processed the Micro-CT data before and after analytical reconstruction. Compared with processing only on tomographic images, the progressive method is better for processing high-noise Micro-CT data. From the objective indicators and visual effects, the differences between the progressive method and other deep learning methods or iterative reconstruction algorithms are analyzed and compared. This paper quantitatively analyzes the effect of the processing network on Micro-CT images with different noise levels, and analyzes the advantages and limitations of GAN in progressive Micro-CT image processing. The progressive Micro-CT image processing method generates images with high quality, fast generation speed, high robustness, and high objective index, which can help further advanced applications such as image segmentation and image 3D visualization.

     

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