IEEE Trans Med Imaging. 2012 Nov;31(11):2120-32. doi: 10.1109/TMI.2012.2213828. Epub 2012 Aug 17.
Dynamic fluorescence diffuse optical tomography (FDOT) is important for the research of drug delivery, medical diagnosis and treatment. Conventionally, dynamic tomographic images are reconstructed frame by frame, independently. This approach fails to account for the temporal correlations in measurement data. Ideally, the entire image sequence should be considered as a whole and a four-dimensional (4-D) reconstruction should be performed. However, the fully 4-D reconstruction is computationally intensive. In this paper, we propose a new 4-D reconstruction approach for dynamic FDOT, which is achieved by applying a temporal Karhunen-Loève (KL) transformation to the imaging equation. By taking advantage of the decorrelation and compression properties of the KL transformation, the complex 4-D optical reconstruction problem is greatly simplified. To evaluate the performance of the method, simulation, phantom, and in vivo experiments (N=7) are performed on a hybrid FDOT/x-ray computed tomography imaging system. The experimental results indicate that the reconstruction images obtained by the KL method provide good reconstruction quality. Additionally, by discarding high-order KL components, the computation time involved with fully 4-D reconstruction can be greatly reduced in contrast to the conventional frame-by-frame reconstruction.
动态荧光漫射光学断层成像（FDOT）在药物输送、医学诊断和治疗的研究中非常重要。传统上，动态断层图像是逐帧独立重建的。这种方法没有考虑到测量数据中的时间相关性。理想情况下，整个图像序列应该被视为一个整体，并进行四维（4-D）重建。然而，完全的 4-D 重建计算量很大。在本文中，我们提出了一种新的动态 FDOT 的 4-D 重建方法，该方法通过将时间 Karhunen-Loève（KL）变换应用于成像方程来实现。通过利用 KL 变换的去相关和压缩特性，大大简化了复杂的 4-D 光学重建问题。为了评估该方法的性能，我们在混合 FDOT/计算机断层扫描成像系统上进行了模拟、体模和体内实验（N=7）。实验结果表明，KL 方法得到的重建图像具有良好的重建质量。此外，通过丢弃高阶 KL 分量，可以大大减少与传统逐帧重建相比的全 4-D 重建所需的计算时间。
