Joshi Amit, Bangerth Wolfgang, Sevick-Muraca Eva
Opt Express. 2004 Nov 1;12(22):5402-17. doi: 10.1364/opex.12.005402.
A three-dimensional fluorescence-enhanced optical tomography scheme based upon an adaptive finite element formulation is developed and employed to reconstruct fluorescent targets in turbid media from frequency-domain measurements made in reflectance geometry using area excitation illumination. The algorithm is derived within a Lagrangian framework by treating the photon diffusion model as a constraint to the optimization problem. Adaptively refined meshes are used to separately discretize maps of the forward/adjoint variables and the unknown parameter of fluorescent yield. A truncated Gauss-Newton method with simple bounds is used as the optimization method. Fluorescence yield reconstructions from simulated measurement data with added Gaussian noise are demonstrated for one and two fluorescent targets embedded within a 512ml cubical tissue phantom. We determine the achievable resolution for the area-illumination/area-detection reflectance measurement geometry by reconstructing two 0.4cm diameter spherical targets placed at at a series of decreasing lateral spacings. The results show that adaptive techniques enable the computationally efficient and stable solution of the inverse imaging problem while providing the resolution necessary for imaging the signals from molecularly targeting agents.
基于自适应有限元公式开发了一种三维荧光增强光学层析成像方案，并将其用于从使用面激发照明在反射几何结构中进行的频域测量中重建浑浊介质中的荧光目标。该算法是在拉格朗日框架内通过将光子扩散模型视为优化问题的约束条件而推导出来的。自适应细化网格用于分别离散正向/伴随变量和荧光产率未知参数的映射。使用具有简单边界的截断高斯-牛顿法作为优化方法。对于嵌入在512ml立方体组织模型中的一个和两个荧光目标，展示了从添加高斯噪声的模拟测量数据中重建荧光产率的情况。我们通过重建一系列横向间距逐渐减小的两个直径为0.4cm的球形目标，确定了面照明/面检测反射测量几何结构可实现的分辨率。结果表明，自适应技术能够在计算上高效且稳定地解决逆成像问题，同时提供对分子靶向剂信号成像所需的分辨率。
