Computational time-of-flight diffuse optical tomography

Abstract

Imaging through a strongly diffusive medium remains an outstanding challenge in particular in association with applications in biological and medical imaging. Here we propose a method based on a single-photon time-of-flight camera that allows, in combination with computational processing of the spatial and full temporal photon distribution data, to image an object embedded inside a strongly diffusive medium over more than 80 transport mean free paths. The technique is contactless and requires one second acquisition times thus allowing Hz frame rate imaging. The imaging depth corresponds to several cm of human tissue and allows one to perform deep-body imaging, here demonstrated as a proof-of-principle.

Time-Gated Single-Photon Detection in Time-Domain Diffuse Optics: A Review

“…Indeed, in the last years several clinical and diagnostics applications [8,131] adopted DOT due to its capability to improve the imaging of deep inhomogeneities of the medium (e.g., tumor, local changes in O 2 Hb/HHb due to brain activation, etc.). The technological improvements in terms of both detectors (matrix of small detectors or large area ones) and detection electronics allows one to have faster measurements, thus going in the direction of real-time tracking of buried objects [132][133][134][135]. Additionally, the use of multiple-view acquisitions coupled to the tomographic reconstruction enables: (i) to overcome the limitation in spatial resolution typical of the diffuse optics; (ii) to improve the quantification of the absorption and scattering coefficient of the inclusion [136][137][138].…”

Robust reconstruction of fluorescence molecular tomography with an optimized illumination pattern

“…Experimental and theoretical work have demonstrated that under the condition of µ a µ s which is exactly the case of our application, light propagation in the medium falls into a strongly diffusive regime. Light within the medium essentially behaves like heat [19] and the photon transport can be modeled by a diffusion approximation with sufficient accuracy [15].…”

Application of Reconstruction and Optimization Algorithms in Optical Tomography

“…Solution therefore does not only involve calculation of optical properties but must also consider scattering effects inside medium. Thus, instead of apply commonly applicable direct method for solving such problems, inversion techniques are considered to evaluate which material properties would have created original signal [14]- [19].…”

“…This trans-illuminated light is scattered through multiple tissues layers and structures present inside tissues. This trans-illuminated light then converted into a series of voltages to amplify, filtered and digitized to construct an image [11] [12] [13] [14]. The data are developed either through time varying intensities or steady state complex intensities of light that have measurable amplitude and phase.…”

“…A lot of work is needed to implement this technique in more fields on its true basis. In this paper, an attempt has been made to give an idea to optimize the constructed image to make this technique more useful [14]- [19].…”