This PDF file contains the Front Matter associated with SPIE Proceedings Volume 7892, including the Title page, Copyright information, Table of Contents, and the Conference Committee listing.

NIRS is safe, non-invasive and offers the possibility to record local hemodynamic parameters at the bedside, avoiding the transportation of neonates and critically ill patients. In this work, we evaluate the accuracy of the frequency-domain multi-distance (FD-MD) method to retrieve brain optical properties from neonate to adult. Realistic measurements are simulated using a 3D Monte Carlo modeling of light propagation. Height different ages were investigated: a term newborn of 38 weeks gestational age, two infants of 6 and 12 months of age, a toddler of 2 year (yr.) old, two children of 5 and 10 years of age, a teenager of 14 yr. old, and an adult. Measurements are generated at multiple distances on the right parietal area of head models and fitted to a homogeneous FD-MD model to estimate the brain optical properties. In the newborn, infants, toddler and 5 yr. old child models, the error was dominated by the head curvature, while the superficial layer in the 10 yr. old child, teenager and adult heads. The influence of the CSF is also evaluated. In this case, absorption coefficients suffer from an additional error. In all cases, measurements at 5 mm provided worse estimation because of the diffusion approximation.

Empirical factors in image reconstruction that can have a dramatic effect on final image quantification in image guided optical spectroscopy using MRI are examined. We present a model for image segmentation that finds that tumor region quantification is influenced by defined size of that region, and we conclude that the most effective segmentation is done using a ktrans map to define the tumor region along with guidance from a radiologist experienced in breast MRI. Data calibration also introduces another empirical factor and we weigh advantages and disadvantages of different methods of calibrating data based on imaging geometry and volume. Finally, we investigate the effects of a modified Levenburg- Marquardt reconstruction that uses a regularization parameter to make the reconstruction less ill-posed and limit the effects of image noise. We find that the regularization parameter must fall within a certain range to adequately smooth the image but if it is too large then image contrast is lost. Understanding and minimizing these factors' contribution will be increasingly important as MRI/NIRS becomes closer to clinical use to ensure that the best possible images are always produced to aid in prognostic clinical decisions.

We present a rapid, noncontact imaging technique which can obtain the spectrally- and spatially-resolved scattering and absorption coefficients of a turbid medium. The measurement involves combining a spatially modulated illumination pattern with a snapshot imaging spectrometer for measurement. After capture of an (x, y, λ) datacube, an image demodulation scheme is applied in post-processing to obtain the spatial maps of diffuse reflectance, absorption coefficient, and reduced scattering coefficient. The resulting system is used to dynamic maps (in 1 s intervals) of the brain's intrinsic optical signal.

Scanning Laser Ophthalmoscopy (SLO) and Coherence Tomography (OCT) are complimentary retinal imaging modalities. Integration of SLO and OCT allows for both fluorescent detection and depth- resolved structural imaging of the retinal cell layers to be performed in-vivo. System customization is required to image rodents used in medical research by vision scientists. We are investigating multimodal SLO/OCT imaging of a rodent model of Stargardt's Macular Dystrophy which is characterized by retinal degeneration and accumulation of toxic autofluorescent lipofuscin deposits. Our new findings demonstrate the ability to track fundus autofluorescence and retinal degeneration concurrently.

This manuscript demonstrates a multimodal imaging system which combined multiphoton microscopy (MPM) imaging modality with Fourier domain (FD) optical coherence microscopy (OCM) imaging modality. The system used a single fiber-based femtosecond laser as the light source for both MPM and OCM modality. The femtosecond fiber laser has a central wavlength of 1.03 μm, a pulse width of 120 fs and a bandwidth of 29 nm. The systems used fiber-based devices for both MPM and OCM imaging. The MPM and OCM shared the same excitation light path. The excitation light was delivered with the core of a dual-clad fiber. The MPM and OCM signal was collected by different parts of the dual-clad fiber. The MPM signal was collected by the clad of the dual-clad fiber and the OCM signal was collected by the core of the dual-clad fiber. The FD OCM used a home-built InGaAs detector array spectrometer with a maximum Aline speed of 7.7 KHz. The multiphoton signal collection efficiency was analyzed and several imaging modality including second harmonic generation imaging, two-photon excited fluorescence and optical coherent microscopy imaging were demonstrated.

Optical coherence tomography (OCT) is a non-invasive in vivo biomedical imaging modality capable of three-dimensional visualization of tissue morphology permitting imaging at high speed and sensitivity. Coherent Anti- Stokes Raman Scattering (CARS) is a nonlinear spectroscopic technique which provides molecular information due to a four wave mixing process. In order to extend the performance of OCT towards detecting the molecular fingerprint of biological samples a combined CARS/OCT setup has been developed that employs only a single ultrashort pulse Ti:Sapphire laser which enables high axial resolution OCT and simultaneously combined with a spectral shaper a CARS setup. During first measurements the same area of a sample was imaged twice, applying OCT and CARS consecutively. OCT was used to perform three-dimensional morphological screening. Due to CARS additional chemical information could be gained for two dimensions. The spectrum was modified computer controlled to match the requirements for the generation of a CARS signal whereas for OCT the unmodified spectrum was applied. Fluids such as dimethylsulfoxide (DMSO) and PBS were compared in a cuvette to demonstrate the functionality of the multimodal setup. As a biological sample a 100 m thickcr oss section through a human optic nerve surrounded by sclera was investigated.

This work examines the robustness of spectral prior to continuous-wave based, with respect to frequency domain based, image reconstruction for unique recovering of chromophores and scattering property distributions. An analytical model for parametric uncertainty in recovering optical property is derived, which afterwards is implemented for optimized selection of wavelengths and quality estimation of the image. Simulation results agree with the theoretical predictions in the following aspects: 1) the proposed analytical model is capable of selecting the optimal set of wavelengths for CW-based spectral reconstruction; 2) with sufficient number of wavelengths, DC-only reconstruction can resolve the concentrations of several important chromophores and scattering parameters, with the accuracy and background artifact level equivalent to those by DC-excluded or DC-included frequency-domain reconstructions; and 3) including DC in frequency-domain reconstruction generally improves reconstruction outcome as compared to when neglecting DC.

Fluorescence-enhanced optical imaging/tomography may play an important role in preclinical research and clinical diagnostics as a type of optical molecular. Time- and frequency-domain measurement can acquire more measurement information, reducing the ill-posedness and improving the reconstruction quality of fluorescence-enhanced optical tomography. Although the diffusion approximation (DA) theory has been extensively in optical imaging, high-order photon migration models must be further investigated for application to complex and small tissue volumes. In this paper, a frequency-domain fully parallel adaptive finite element solver is developed with the simplified spherical harmonics (SP_N) approximations. To fully evaluate the performance of the SP_N approximations, a fast tetrahedron-based Monte Carlo simulator suitable for complex heterogeneous geometries is developed using the convolution strategy to realize the simulation of the fluorescence excitation and emission. With simple and real digital mouse phantoms, the results show that the significant precision and speed improvements are obtained from the parallel adaptive mesh evolution strategy.

Time reversal optical tomography (TROT) approach is used to detect and locate absorptive targets embedded in a highly scattering turbid medium to assess its potential in breast cancer detection. TROT experimental arrangement uses multi-source probing and multi-detector signal acquisition and Multiple-Signal-Classification (MUSIC) algorithm for target location retrieval. Light transport from multiple sources through the intervening medium with embedded targets to the detectors is represented by a response matrix constructed using experimental data. A TR matrix is formed by multiplying the response matrix by its transpose. The eigenvectors with leading non-zero eigenvalues of the TR matrix correspond to embedded objects. The approach was used to: (a) obtain the location and spatial resolution of an absorptive target as a function of its axial position between the source and detector planes; and (b) study variation in spatial resolution of two targets at the same axial position but different lateral positions. The target(s) were glass sphere(s) of diameter ~9 mm filled with ink (absorber) embedded in a 60 mm-thick slab of Intralipid-20% suspension in water with an absorption coefficient μ_a ~ 0.003 mm^-1 and a transport mean free path l_t ~ 1 mm at 790 nm, which emulate the average values of those parameters for human breast tissue. The spatial resolution and accuracy of target location depended on axial position, and target contrast relative to the background. Both the targets could be resolved and located even when they were only 4-mm apart. The TROT approach is fast, accurate, and has the potential to be useful in breast cancer detection and localization.

We investigate the feasibility of 3-D localization of Foerster resonance energy transfer (FRET) between two NIR fluorophores (Alexa Fluor 700 and Alexa Fluor 750) in small animal models. Specifically, the decrease in donor lifetime upon FRET is used as the contrast mechanism to isolate donor-acceptor pairs undergoing FRET. The optical tomography system uses a femtosecond tunable laser coupled with a micro-mirror device based digital light processor as the source to generate wide-field patterns. The time-resolved detection is achieved using a gated intensified CCD camera. The wide-field excitation scheme described herein provides an experimental advantage by reducing the time of acquisition of temporally dense datasets. In this study, anatomical information obtained using MR imaging is used in the computation of the Monte Carlo (MC) based forward model. The MC model reconstructs the 3D distribution of the quantum yield of the donor fluorophore and the FRET complex using the time-gate data type allowing the estimation of fractional distribution (ƒ_D) of donor molecules undergoing FRET and unquenched donor molecules. The performance of this approach in the estimation of ƒ_D using the position of fluorophores obtained using the MRI is investigated.

An instrument dedicated to the co-registration of optical and X-ray measurements is presented: specific acquisition protocol and reconstruction software have been developed for carrying out fluorescence diffuse optical tomography in a cylindrical geometry consistent with XCT. Actual animal geometry provided by the X-ray tomography is used to give animal boundaries to the diffuse optical tomography reconstruction algorithm. To evaluate performances of this new optical imaging system, experiments have been conducted on phantoms, mice with fluorescent capillaries, and finally on mice bearing tumors. The fluorescence reconstructions are shown to be geometrically consistent with X-ray ones. We determined that the sensibility limit of the system to detect fluorescence signal over intrinsic ones is 2 pmol for lungs area and 5 pmol for the abdomen area.

In this paper we present the details of a Diffuse Optical Tomographic (DOT) prototype instrument developed and characterized at RMD for concurrent operation with Magnetic Resonance Imaging (MRI) to obtain high resolution spatial and functional images of hypoxic tumor tissue. We have developed a new system designed for in-vivo imaging of luminescent agents that respond to tissue oxygenation to improve the contrast and spatial resolution of functional optical images in deep tissue. High-resolution spatial and anatomical information obtained from MRI images is used to improve the accuracy of the reconstructed optical images. The time domain lifetime imaging module has parallel acquisition across a cooled 16-element avalanche photodiode (APD) array for high resolution and high throughput imaging. The low-cost, compact lifetime imager is compatible with high magnetic and RF fields associated with MR units in hybrid imaging systems. Using this APD module in a dual-modality imaging setup, phantom imaging was performed to obtain oxygenation images with high resolution and contrast. Optical image reconstruction is aided by spatial guidance obtained from the actual phantom dimensions to improve the accuracy of these images.

In vivo experiments using a hybrid DOT and MRI system are undertaken on small animals in this study. MRI structural a priori information is utilized for constraining and guiding DOT chromophore reconstruction. Even though in the past, multi-wavelength DOT has been extensively evaluated with phantom and clinical studies, there have been very few small animal studies reported in literature. In this small animal study, chromophore reconstruction results for different tumor types are presented and compared. The goal of this study is to evaluate the performance of the hybrid MRI-DOT system in vivo.

A case study to demonstrate fluorescence tomography of endogenous protoporphyrin IX (PPIX) in breast cancer is presented. An MRI-coupled fluorescence tomography system with spectrometer detectors was used to acquire excitation and emission data through the breast of a human subject undergoing chemotherapy for breast cancer. Volumetric images of PPIX fluorescence showed elevated levels of fluorescence activity in the fibro-glandular tissue as compared to the adipose tissue. Fluorescence levels in the tumor were higher than in the adipose tissue but lower than the fibro-glandular tissue.

Osteoporosis is a bone disease that leads to the increasing risk of bone fracture. It is associated with a reduced mineral content, which results in the change of the bone architecture. Raman spectroscopy has an intrinsic sensitivity to the chemical content of the bone, but its application to study bones in vivo is limited due to strong optical scattering in tissue. It is proposed that Raman excitation with photoacoustic detection can successfully address the problem of chemically specific imaging in deep tissue. In this report, the principal possibility of such approach is evaluated.

A diffusely infiltrative human glioma cell line (U251-GFP) has been developed and used as a model for the tumor growth outside of MR image detectable tumor boundary. The aminolevulinic acid-protoporphyrin IX (ALA-PpIX) fluorescence system has shown great strides for fluorescence guided surgical resection, but often fluorescence is observed outside of the MR image detectable tumor margin. Here we compare the use of ALA-PpIX fluorescence with that of standard gadolinium enhanced MR imaging as well as T2 and diffusion imaging to determine whether there is a correlation between fluorescence and MR imaging. We found that PpIX fluorescence, T1WCD and Absolute T2 images have the highest contrast difference from controls and are likely candidates for highly infiltrative tumor detection.

Different optical spectral characteristics were observed in a necrotic transmissible venereal tumor (TVT) and a cystic lesion in the same canine prostate by triple-wavelength trans-rectal optical tomography under trans-rectal ultrasound (TRUS) guidance. The NIR imager acquiring at 705nm, 785nm and 808nm was used to quantify both the total hemoglobin concentration (HbT) and oxygen saturation (StO2) in the prostate. The TVT tumor in the canine prostate as a model of prostate cancer was induced in a 7-year old, 27 kg dog. A 2 mL suspension of 2.5x10⁶ cells/mL of homogenized TVT cells recovered from an in vivo subcutaneously propagated TVT tumor in an NOD/SCID mouse were injected in the cranial aspect of the right lobe of the canine prostate. The left lobe of the prostate had a cystic lesion present before TVT inoculation. After the TVT homogenate injection, the prostate was monitored weekly over a 9-week period, using trans-rectal NIR and TRUS in grey-scale and Doppler. A TVT mass within the right lobe developed a necrotic center during the later stages of this study, as the mass presented with substantially increased [HbT] in the periphery, with an area of reduced StO2 less than the area of the mass itself shown on ultrasonography. Conversely, the cystic lesion presented with slightly increased [HbT] in the periphery of the lesion shown on ultrasound with oxygen-reduction inside and in the periphery of the lesion. There was no detectable change of blood flow on Doppler US in the periphery of the cystic lesion. The slightly increased [HbT] in the periphery of the cystic lesion was correlated with intra-lesional hemorrhage upon histopathologic examination.

We present a scheme for fluorescence guided diffusion optical tomography to reconstruct the fluorescence parameters (yield and lifetime) and optical parameters (absorption and reduced coefficients) based on time-resolved data. In this paper, the fluorescence parameters were reconstructed at first, then the fluorescence images were used to guide and constrain the diffusion optical tomography reconstruction, and the binary image segmentation strategy was applied to improve the image quality in DOT. To validate the proposed method, the numerical simulation was performed to demonstrate its computational efficacy. The results showed the feasibility of this method, and the spatial resolution, quantification and computational efficiency in DOT were enhanced evidently.

Ultrasound poroelastography can quantify structural and mechanical properties of tissues such as stiffness, compressibility, and fluid flow rate. This novel ultrasound technique is being explored to detect tissue changes associated with lymphatic disease. We have constructed a macroscopic fluorescence imaging system to validate ultrasonic fluid flow measurements and to provide high resolution imaging of microfluidic phantoms. The optical imaging system is composed of a white light source, excitation and emission filters, and a camera with a zoom lens. The field of view can be adjusted from 100 mm x 75 mm to 10 mm x 7.5 mm. The microfluidic device is made of polydimethylsiloxane (PDMS) and has 9 channels, each 40 μm deep with widths ranging from 30 μm to 200 μm. A syringe pump was used to propel water containing 15 μm diameter fluorescent microspheres through the microchannels, with flow rates ranging from 0.5 μl/min to 10 μl/min. Video was captured at a rate of 25 frames/sec. The velocity of the microspheres in the microchannels was calculated using an algorithm that tracked the movement of the fluorescent microspheres. The imaging system was able to measure particle velocities ranging from 0.2 mm/sec to 10 mm/sec. The range of flow velocities of interest in lymph vessels is between 1 mm/sec to 10 mm/sec; therefore our imaging system is sufficient to measure particle velocity in phantoms modeling lymphatic flow.

In this article, we derive the two-dimensional spherical harmonics equations to three-order (P₃) of Radiative Transfer Equation for anisotropic scattering. We also solved this equations using Galerkin finite element method and compared the solutions with the first-order diffusion equation and Monte Carlo simulation. the benchmark problems are tested, and we found that the developed three-order model with high absorb coefficient is able to significantly improve the diffusion solution in circle geometry, and the radiance distribution close to light source is more accurate. It is significant for accurate modeling of light propagation in small tissue geometries in small animal imaging. Then, the inverse model for the simultaneous reconstruction of the absorption images is proposed based on P3 equations, and the feasibility and effectiveness of this method are proved by the simulation.

An optical integrating system composed of optical coherence tomography (OCT) and fluorescence spectroscopy (FS) has been designed and utilized to distinguish pearls by determining their mother oysters used in pearl culturing as well as discriminate and evaluate the pearls, nondestructively. By adopting a wavelength division multiplexing (WDM) and a double clad fiber (DCF) coupler, a FS system could be successfully combined with a fiber-based swept source OCT (SSOCT) system. Applying a common-path configuration, furthermore, the integrating system could be implemented in a simple and effective way with highly minimized group velocity dispersion (GVD) and polarization mismatch problems. The internal structure measurement and the fluorescence spectrum measurement, which were previously performed by two independent apparatus, were concurrently made with the proposed system. From the OCT measurement, we could measure the thickness of the nacre layer, observe the fine sub-structure of the nacre, and inspect the nucleus through the nacre of a pearl. With the fluorescence spectrum measurement, we could categorize the pearls by determining their mother oysters.

Skin penetration studies are an important part for the development of dermal drug carrier systems. As a novel approach a 7-tesla Magnetic Resonance Imaging (MRI) Scanner was used to obtain information about the penetration of agents into the skin. The main advantage of this method is, that the properties of the skin does not influence the signals. Compared to optical assessments the MRI method is not limited to imaging depth. Furthermore, it is possible to analyze fat and water components of the skin separately. The aim of this work was to evaluate, if this method is a promising analysis tool for the visualization of the transport of substances across the skin. Gadobutrol (Gadovist^®1.0), respresenting a coventional contrast agent in MRI, was used as a model drug for the visualization of the skin penetration. These first promising results showed that Gadobutrol, incorporated in an oil-in-water emulsion, could be detected across the skin tissue compared to an aqueous solution. After 24 hours, the pixel intensity value was increased about 4-fold compared to an untreated tissue.

Intravascular Near-Infrared Fluorescence (NIRF) imaging is a promising imaging modality to image vessel biology and high-risk plaques in vivo. We have developed a NIRF fiber optic catheter and have presented the ability to image atherosclerotic plaques in vivo, using appropriate NIR fluorescent probes. Our catheter consists of a 100/140 μm core/clad diameter housed in polyethylene tubing, emitting NIR laser light at a 90 degree angle compared to the fiber's axis. The system utilizes a rotational and a translational motor for true 2D imaging and operates in conjunction with a coaxial intravascular ultrasound (IVUS) device. IVUS datasets provide 3D images of the internal structure of arteries and are used in our system for anatomical mapping. Using the IVUS images, we are building an accurate hybrid fluorescence-IVUS data inversion scheme that takes into account photon propagation through the blood filled lumen. This hybrid imaging approach can then correct for the non-linear dependence of light intensity on the distance of the fluorescence region from the fiber tip, leading to quantitative imaging. The experimental and algorithmic developments will be presented and the effectiveness of the algorithm showcased with experimental results in both saline and blood-like preparations. The combined structural and molecular information obtained from these two imaging modalities are positioned to enable the accurate diagnosis of biologically high-risk atherosclerotic plaques in the coronary arteries that are responsible for heart attacks.

Ovarian cancer has the lowest survival rate of the gynecologic cancers with a 5-year survival of about 50% in the United States. With current screening and diagnostic abilities for ovarian cancers, most of the diagnosed patients are already with advanced stages and the majority of them will die of this deadly disease. In this paper, we report a multimodal imaging approach which combines optical coherence tomography (OCT) and positron detection for early ovarian cancer detection. The dual modality system has the capability of providing both functional and morphological images simultaneously. While the positron detection provides the metabolism activity of the ovary due to the uptake of radiotracer, the OCT provides the high resolution (25μm X 25μm X 12μm - longitudinal X lateral X axial in air) structural imaging at 20k A-lines per second. Total 18 ovaries obtained from 10 patients classified as normal, abnormal and malignant ovarian tissues were characterized ex vivo. Positron counts of 1.2-fold higher was found between abnormal and normal ovaries and 3~30-fold higher was found between malignant and normal ovaries. OCT imaging of malignant and abnormal ovaries revealed many detailed morphologic features that could be potentially valuable for detecting early malignant changes in the ovary.

Dynamic contrast enhanced MRI (DCE-MRI) has been proven to be the most sensitive modality in detecting breast lesions. Currently available MR contrast agent, Gd-DTPA, is a low molecular weight extracellular agent and can diffuse freely from the vascular space into interstitial space. Due to this reason, DCE-MRI has low sensitivity in differentiating benign and malignant tumors. Meanwhile, diffuse optical tomography (DOT) can be used to provide enhancement kinetics of an FDA approved optical contrast agent, ICG, which behaves like a large molecular weight optical agent due to its binding to albumin. The enhancement kinetics of ICG may have a potential to distinguish between the malignant and benign tumors and hence improve the specificity. Our group has developed a high speed hybrid MRI-DOT system. The DOT is a fully automated, MR-compatible, multi-frequency and multi-spectral imaging system. Fischer-344 rats bearing subcutaneous R3230 tumor are injected simultaneously with Gd-DTPA (0.1nmol/kg) and IC-Green (2.5mg/kg). The enhancement kinetics of both contrast agents are recorded simultaneously with this hybrid MRI-DOT system and evaluated for different tumors.

We investigated the kinetics of a bolus intravenous administrated normal saline by using near-infrared diffuse optical technique, and compared it with the kinetics of a non-targeted contrast agent indocyanine green (ICG) on small animal tumor model. Two-compartment model was used to fit the dynamic curves at early stage, which considered saline and ICG as either a negative or positive contrast agent. The purposes of the designed experiment reported here are to (1) study the effect of saline administration on optical pharmacokinetics; (2) investigate the possibility of using normal saline as contrast agent for the study of tumor pathophysiology. The study indicates that saline has different contrast mechanism as ICG, and saline can provide enough optical contrast for the tumor kinetic study.

Recovery of Raman or Fluorescence signatures from within thin tissues benefits from model-based estimation of where the signal came from, especially if the signal passes through layers in which the absorption or scattering signatures distort the signal. Estimation of the signal strength requires appropriate normalization or model-based recovery, but the key to achieving good results is a good model of light transport. While diffusion models are routinely used for optical tomography of tissue, there's some thought that more precise radiation transport modeling is required for accurate estimation. However, diffusion is often used for small animal imaging, because it's a practical approach, which doesn't require knowledge of the scatter phase function at each point in the tissue. The question asked in this study is, whether experimentally acquired data in small volumes such as a rodent leg can be accurately modeled and reconstructed using diffusion theory. This study uses leg geometries extracted from animal CT scans and liquid phantoms to study the diffusion approximations. The preliminary results show that under certain conditions the collected data follows the expected trend.

Fluorescence diffuse optical tomography (FT) is a molecular imaging technique that can create images of spatially resolved fluorophore concentrations and fluorescence lifetimes. One problem faced by FT is that the recovered fluorophore parameters greatly depend on the size and depth of the inclusion due to the ill-posedness of the FT inverse problem. Structural a priori information from imaging modalities with high spatial resolution is demonstrated to significantly improve the accuracy of the FT reconstruction. We have constructed a hybrid FT/MRI system for small animal imaging in this study. Near-infrared light was delivered and collected by optical fibers that connect the FT/MRI system to the interface in the MRI bore. We investigated the feasibility of a photo-multiplier tube (PMT) based detection system that acquired time-resolved data in the frequency domain. Phantom studies were used to evaluate the performance of the combined system. The concentration and lifetime maps were reconstructed with and without the structural a priori information obtained from MRI. ICG and DTTCI, two fluorophores with similar excitation and emission spectra but different lifetimes, were used in this evaluation. Specifically, we showed that the PMT-based frequency domain hybrid system was capable of differentiating between two fluorophores with different fluorescence lifetimes. Furthermore, this process was shown to be more accurate when MR a priori is used.

A fluorescence imaging system was designed to interface with a microCT device. We focus on refining the workflow for meshing and the coordinate registration of the two systems. The former is performed by projection imaging in the microCT, reconstructing a volume, segmenting using image processing software, and meshing using the NIRFAST software. The coordinate registration is performed by exploiting the geometry of the fluorescence system. We determine the location of the geometrical center of a subject, which can be used to derive a translation between instruments. The co-registration is validated by imaging optical phantoms.