Smart Toolkit for Fluorescence Tomography: Simulation, Reconstruction, and Validation

Abstract

Fluorescence molecular tomography (FMT) can provide valuable molecular information by mapping the bio-distribution of fluorescent reporter molecules in the intact organism. Various prototype FMT systems have been introduced during the past decade. However, none of them has evolved as a standard tool for routine biomedical research. The goal of this paper is to develop a software package that can automate the complete FMT reconstruction procedure. Methods: We present smart toolkit for fluorescence tomography (STIFT), a comprehensive platform comprising three major protocols: 1) virtual FMT, i.e., forward modeling and reconstruction of simulated data; 2) control of actual FMT data acquisition; and 3) reconstruction of experimental FMT data. Results: Both simulation and phantom experiments have shown robust reconstruction results for homogeneous and heterogeneous tissue-mimicking phantoms containing fluorescent inclusions. Conclusion: STIFT can be used for optimization of FMT experiments, in particular for optimizing illumination patterns. Significance: This paper facilitates FMT experiments by bridging the gaps between simulation, actual experiments, and data reconstruction.

Non-invasive visualization of amyloid-beta deposits in Alzheimer amyloidosis mice using magnetic resonance imaging and fluorescence molecular tomography

“…As the highly scattering nature of tissue renders FMT an ill-posed problem, implementing such prior information significantly improves the registration results (Arridge and Schotland, 2009). We have demonstrated the robustness and accuracy of the FMT-MRI method by using tissue-mimicking phantoms (Ren et al, 2020b) and in biological studies using a tumor-bearing mouse model (Ren et al, 2020a) or ex vivo intervertebral discs (Ren et al, 2021a).…”

Multimodal imaging combining time-domain near-infrared optical tomography and continuous-wave fluorescence molecular tomography

“…In TD-NIROT, the time derivative term can be approximated by a finite-difference scheme. The details for FEM formulation and inversion are referred to [19].…”

“…For FMT reconstruction, we used a modular software platform (STIFT) [19] with integrated modular functions, including meshing (by calling iso2mesh [40]), forward modeling (by calling TOAST++ [41]), various inversion and visualization methods. According to the geometry of the cylindrical phantom, a tetrahedral mesh was generated for FEM modeling.…”

“…nBorn approximation accounts for the heterogeneity of absorption to a certain degree but is less effective concerning the heterogeneity of scattering [14,16]. Optical properties may be attributed to specific tissues by combining FMT with another high-resolution imaging method, such as X-ray computed tomography (CT) or magnetic resonance imaging (MRI), which serves as a structural reference [3,[17][18][19][20][21]. The acquired structural image is segmented into different regions, each characterized by a specific property value.…”

“…It also enables non-contact measurements and is simple to integrate into other optical imaging modalities, such as FMT. In this work, we have developed a multimodal imaging strategy by using the novel TD-NIROT and a previously reported CW-FMT system [19,35]. Both NIROT and FMT measurements were conducted on a semitransparent cylindrical phantom with an optical heterogeneity and a fluorescent inclusion.…”