Linear 3D reconstruction of time-domain diffuse optical imaging differential data: improved depth localization and lateral resolution

Optics Express (Impact Factor: 3.49). 01/2008; 15(25):16400-12. DOI: 10.1364/OE.15.016400
Source: PubMed


We present 3D linear reconstructions of time-domain (TD) diffuse optical imaging differential data. We first compute the sensitivity matrix at different delay gates within the diffusion approximation for a homogeneous semi-infinite medium. The matrix is then inverted using spatially varying regularization. The performances of the method and the influence of a number of parameters are evaluated with simulated data and compared to continuous-wave (CW) imaging. In addition to the expected depth resolution provided by TD, we show improved lateral resolution and localization. The method is then applied to reconstructing phantom data consisting of an absorbing inclusion located at different depths within a scattering medium.

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Available from: Juliette Selb, Apr 09, 2015
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    • "Using time-resolved photo-sensing methods, the spread of the temporally focused (i.e., narrow pulse) light input is characterized to reveal the underlying biological tissue: the pulse intensity signifies tissue attenuation, the pulse width is tightly related to tissue scattering, and the pulse delay is related to both tissue thickness and scattering. More in-depth discussions of the quantitative relation of these parameters can be found in [62, 65, 66, 67, 68, 69, 70]. A special case of the temporal modulation methods is the so-called early photon (also known as ballistic photon) imaging method, which uses ultrafast laser and detector time-gating to reduce the TPSF of the imaging system, thereby improving the spatial resolution [71, 72, 73]. "
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    ABSTRACT: Diffuse optical imaging is highly versatile and has a very broad range of applications in biology and medicine. It covers diffuse optical tomography, fluorescence diffuse optical tomography, bioluminescence, and a number of other new imaging methods. These methods of diffuse optical imaging have diversified instrument configurations but share the same core physical principle - light propagation in highly diffusive media, i.e., the biological tissue. In this review, the author summarizes the latest development in instrumentation and methodology available to diffuse optical imaging in terms of system architecture, light source, photo-detection, spectral separation, signal modulation, and lastly imaging contrast.
    Photonics 03/2014; 1(1):9-32. DOI:10.3390/photonics1010009
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    • "However, from 20 mm to deeper, the depth is underestimated even with 108 photons. This effect was already observed by Selb et al. starting from the depth of 25 mm for an interfiber distance of 25 mm [22]. "
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    ABSTRACT: We show how to apply the Mellin-Laplace transform to process time-resolved reflectance measurements for diffuse optical tomography. We illustrate this method on simulated signals incorporating the main sources of experimental noise and suggest how to fine-tune the method in order to detect the deepest absorbing inclusions and optimize their localization in depth, depending on the dynamic range of the measurement. To finish, we apply this method to measurements acquired with a setup including a femtosecond laser, photomultipliers and a time-correlated single photon counting board. Simulations and experiments are illustrated for a probe featuring the interfiber distance of 1.5 cm and show the potential of time-resolved techniques for imaging absorption contrast in depth with this geometry.
    Biomedical Optics Express 04/2013; 4(4):569-83. DOI:10.1364/BOE.4.000569 · 3.65 Impact Factor
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    • "FD and TR provide significant advantages with respect to CW approach. In particular, they allow to separate absorption and diffusion contributions [21], to derive fluorescence lifetime [22] and more generally to provide a data set with a higher information content which can lead to better reconstruction of deeply-embedded markers [23]. This last aspect, is particularly relevant for TR measurements, which contain any modulation frequency, while FD measurements can only be performed, in practice, for few of them. "
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    ABSTRACT: Context and objectives. - In the context of fluorescence diffuse optical tomography, the time-resolved approach was shown to improve the reconstruction quality compared to the continuous-wave approach when adopting the transmittance configuration. However, the improvement seriously decreases in the presence of noise. The scope of this paper is to investigate the additional value of the time-resolved approach in the reflectance configuration. Material and methods. - A comparative study between time-resolved and continuous-wave reconstructions is provided in the reflectance configuration. Reconstructions are performed from synthetic measurements in a slab geometry assuming Poisson noise statistics. Results and discussion. - In the reflectance configuration, the reconstruction quality, expressed in terms of the global reconstruction error or in terms of the localization and quantification of a local inclusion, is shown to be sensibly higher when the time-resolved approach is considered rather than the continuous-wave one. This behavior is observed for which the maximum number of detected photons is around 10(6). Conclusion. - In the reflectance configuration, considering realistic level of signal the time-resolved approach is shown to outperform continuous-wave approach.
    IRBM 09/2011; 32(4):243-250. DOI:10.1016/j.irbm.2011.04.001 · 0.52 Impact Factor
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