Melli S Ali, Wahid Khan A, Babyn Paul, Cooper David M L, Gopi Varun P
Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, Saskatchewan S7N5A9, Canada.
Department of Medical Imaging, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada.
Rev Sci Instrum. 2016 Dec;87(12):123701. doi: 10.1063/1.4968198.
Synchrotron X-ray Micro Computed Tomography (Micro-CT) is an imaging technique which is increasingly used for non-invasive in vivo preclinical imaging. However, it often requires a large number of projections from many different angles to reconstruct high-quality images leading to significantly high radiation doses and long scan times. To utilize this imaging technique further for in vivo imaging, we need to design reconstruction algorithms that reduce the radiation dose and scan time without reduction of reconstructed image quality. This research is focused on using a combination of gradient-based Douglas-Rachford splitting and discrete wavelet packet shrinkage image denoising methods to design an algorithm for reconstruction of large-scale reduced-view synchrotron Micro-CT images with acceptable quality metrics. These quality metrics are computed by comparing the reconstructed images with a high-dose reference image reconstructed from 1800 equally spaced projections spanning 180°. Visual and quantitative-based performance assessment of a synthetic head phantom and a femoral cortical bone sample imaged in the biomedical imaging and therapy bending magnet beamline at the Canadian Light Source demonstrates that the proposed algorithm is superior to the existing reconstruction algorithms. Using the proposed reconstruction algorithm to reduce the number of projections in synchrotron Micro-CT is an effective way to reduce the overall radiation dose and scan time which improves in vivo imaging protocols.
同步加速器X射线显微计算机断层扫描（Micro-CT）是一种成像技术，越来越多地用于非侵入性体内临床前成像。然而，它通常需要从许多不同角度进行大量投影以重建高质量图像，这导致辐射剂量显著增加和扫描时间延长。为了进一步将这种成像技术用于体内成像，我们需要设计重建算法，在不降低重建图像质量的情况下减少辐射剂量和扫描时间。本研究的重点是结合基于梯度的道格拉斯-拉赫福德分裂法和离散小波包收缩图像去噪方法，设计一种算法，用于重建具有可接受质量指标的大规模少视图同步加速器Micro-CT图像。这些质量指标是通过将重建图像与从跨越180°的1800个等间距投影重建的高剂量参考图像进行比较来计算的。在加拿大光源的生物医学成像与治疗弯曲磁铁光束线中对合成头部模型和股骨皮质骨样本进行成像，并基于视觉和定量的性能评估表明，所提出的算法优于现有的重建算法。使用所提出的重建算法减少同步加速器Micro-CT中的投影数量是减少总体辐射剂量和扫描时间的有效方法，这改进了体内成像方案。
