Abstract:A non-contact galvanometer-based optical scanning system for diffuse correlation tomography was developed for monitoring bone graft healing in a murine femur model. A linear image reconstruction algorithm for diffuse correlation tomography was tested using finite-element method based simulated data and experimental data from a femur or a tube suspended in a homogeneous liquid phantom. Finally, the non-contact system was utilized to monitor in vivo blood flow changes prior to and one week after bone graft transplantation within murine femurs. Localized blood flow changes were observed in three mice, demonstrating a potential for quantification of longitudinal blood flow associated with bone graft healing.

A scanning system for small animal imaging using non-contact, hybrid broadband diffuse optical spectroscopy (ncDOS) and diffuse correlation spectroscopy (ncDCS) is presented. The ncDOS uses a two-dimensional spectrophotometer retrieving broadband (610-900 nm) spectral information from up to fifty-seven sourcedetector distances between 2 and 5 mm. The ncDCS data is simultaneously acquired from four source-detector pairs. The sample is scanned in two dimensions while tracking variations in height. The system has been validated with liquid phantoms, demonstrated in vivo on a human fingertip during an arm cuff occlusion and on a group of mice with xenoimplanted renal cell carcinoma. ©2016 Optical Society of America

We introduce, for the first time, a wearable, modular, and fiberless fNIRS system made of diamond-shaped flexible-circuit-based modules, capable of full-head coverage, acquisition of 3-D positions, utilizing inter-module channels, and high flexibility in connection re-configurations.

. Significance : The expansion of functional near-infrared spectroscopy (fNIRS) systems toward broader utilities has led to the emergence of modular fNIRS systems composed of repeating optical source/detector modules. Compared to conventional fNIRS systems, modular fNIRS systems are more compact and flexible, making wearable and long-term monitoring possible. However, the large number of design parameters makes understanding their impact on a probe’s performance a daunting task. Aim : We aim to create a systematic software platform to facilitate the design, characterization, and comparison of modular fNIRS probes. Approach : Our software—modular optode configuration analyzer (MOCA)—implements semi-automatic algorithms that assist in tessellating user-specified regions-of-interest, in interconnecting modules of various shapes, and in quantitatively comparing probe performance using metrics, such as spatial channel distributions and average brain sensitivity of the resulting probes. There is also support for limited parameter sweeping capabilities. Results : Through several examples, we show that users can use MOCA to design and optimize modular fNIRS probes, study trade-offs between several module shapes, improve brain sensitivity in probes via module re-orientation, and enhance probe performance via adjusting module spatial layouts. Conclusion : Despite its simplicity, our modular probe design platform offers a framework to describe and quantitatively assess probes made by modules, opening a new door for the growing fNIRS user community to approach the challenging problem of module- and probe-parameter selection and fine-tuning.

Diffuse optical tomography (DOT) has emerged over the past few decades as a non-invasive imaging tool to quantitatively assess deep tissue's functional and anatomical information. It has seen widespread use in various preclinical and clinical research fields, leading to a cumulative understanding of the technique and its potential applications. Over the years, the field of diffuse optics has encountered increasingly complex limitations, including ill-posedness, processing time, limited optodes density, etc., giving rise to novel and more sophisticated developments on the theoretical, algorithmic, computational, and instrumentation levels. In this chapter, we aim to present the theoretical basis of near-infrared diffuse optical tomography and diffuse correlation tomography. We introduce the state-of-the-art in computational and algorithmic perspectives, which seeks to improve the spatial resolution of reconstructed images while concurrently reducing the computational burden of solving high-dimensional inverse problems. We conclude by providing a survey of the most relevant applications of DOT currently undergoing clinical testing.

Abstract:The longitudinal effect of an anti-vascular endothelial growth factor receptor 2 (VEGFR-2) antibody (DC 101) therapy on a xenografted renal cell carcinoma (RCC) mouse model was monitored using hybrid diffuse optics. Two groups of immunosuppressed male nude mice (seven treated, seven controls) were measured. Tumor microvascular blood flow, total hemoglobin concentration and blood oxygenation were investigated as potential biomarkers for the monitoring of the effect of therapy twice a week and were related to the final treatment outcome. These hemodynamic biomarkers have shown a clear differentiation between two groups by day four. Moreover, we have observed that pre-treatment values and early changes in hemodynamics are highly correlated with the therapeutic outcome demonstrating the potential of diffuse optics to predict the therapy response at an early time point. References and links1. J. Folkman, "What is the evidence that tumors are angiogenesis dependent?" J. Natl. Cancer Inst. 82(1), 4-6 (1990). 2. J. Folkman, "Angiogenesis in cancer, vascular, rheumatoid and other disease," Nat. Med. 1(1), 27-30 (1995). 3. P. Carmeliet and R. K. Jain, "Angiogenesis in cancer and other diseases," Nature 407(6801), 249-257 (2000). 4. N. Ferrara, H.-P. Gerber, and J. LeCouter, "The biology of VEGF and its receptors," Nat. Med. 9(6), 669-676 (2003). 5. J. Folkman, "Angiogenesis: an organizing principle for drug discovery?" Nat. Rev. Drug Discov. 6(4), 273-286 (2007). 6. L. M. Ellis and D. J. Hicklin, "VEGF-targeted therapy: mechanisms of anti-tumour activity," Nat. Rev. Cancer 8(8), 579-591 (2008

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