Jha Abhinav K, Clarkson Eric, Kupinski Matthew A
College of Optical Sciences, University of Arizona, Tucson, AZ, USA.
Biomed Opt Express. 2013 Sep 9;4(10):2107-23. doi: 10.1364/BOE.4.002107. eCollection 2013.
With the emergence of diffuse optical tomography (DOT) as a non-invasive imaging modality, there is a requirement to evaluate the performance of the developed DOT systems on clinically relevant tasks. One such important task is the detection of high-absorption signals in the tissue. To investigate signal detectability in DOT systems for system optimization, an appropriate approach is to use the Bayesian ideal observer, but this observer is computationally very intensive. It has been shown that the Fisher information can be used as a surrogate figure of merit (SFoM) that approximates the ideal observer performance. In this paper, we present a theoretical framework to use the Fisher information for investigating signal detectability in DOT systems. The usage of Fisher information requires evaluating the gradient of the photon distribution function with respect to the absorption coefficients. We derive the expressions to compute the gradient of the photon distribution function with respect to the scattering and absorption coefficients. We find that computing these gradients simply requires executing the radiative transport equation with a different source term. We then demonstrate the application of the SFoM to investigate signal detectability in DOT by performing various simulation studies, which help to validate the proposed framework and also present some insights on signal detectability in DOT.
随着扩散光学断层扫描（DOT）作为一种非侵入性成像方式的出现，需要评估所开发的DOT系统在临床相关任务上的性能。其中一项重要任务是检测组织中的高吸收信号。为了在DOT系统中研究信号可检测性以进行系统优化，一种合适的方法是使用贝叶斯理想观察者，但这种观察者的计算量非常大。研究表明，费舍尔信息可以用作近似理想观察者性能的替代品质因数（SFoM）。在本文中，我们提出了一个理论框架，用于使用费舍尔信息来研究DOT系统中的信号可检测性。费舍尔信息的使用需要评估光子分布函数相对于吸收系数的梯度。我们推导了计算光子分布函数相对于散射和吸收系数梯度的表达式。我们发现，计算这些梯度只需用不同的源项求解辐射传输方程。然后，我们通过进行各种模拟研究来展示SFoM在研究DOT中信号可检测性方面的应用，这些研究有助于验证所提出的框架，并对DOT中的信号可检测性提供一些见解。
