This PDF file contains the front matter associated with SPIE Proceedings Volume 10870 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

To prevent contaminations and infections, various precautions are taken in an OR environment. Personnel wear masks and special clothing and a laminar flow of clean air is created within the sterile operating field. However, this controlled environment can easily be disturbed by the movements of personnel and medical equipment with internal cooling fans. In progress of a previous study, a special large field air flow visualization technique has been adapted to study and quantify the air flow around equipment used in the OR in real-time. Optical distortions induced by small density gradients in flowing air can be visualized with high contrast and sensitivity in real time by subtraction of the fine line pattern in the background of the field of interest from the live video signal. This technique was used to study the effectiveness of surgical masks, the disturbance of the laminar flow by the exhaust of cooling air from equipment like an operating microscope and surgical navigation system. Due to the real-time visualization, it is possible to focus on the region of interest and the instant effect of e.g. repositioning of equipment. Recording can be analyzed later to quantification. Real time large field air flow imaging shows to be a sensitive and qualitative technique to study air flows. The awareness of the disturbance of the clean laminar air flow should lead to guidelines to improve the design and positioning of medical equipment in the OR to reduce infections.

Monte-Carlo (MC) simulations of photon migration are frequently used to build lookup tables modelling experimental results in Near-Infrared Spectroscopy. The optical properties of samples are inferred by minimizing χ²-deviation between MC model and experiment. Even for long MC simulations these lookup tables contain Poisson noise especially at high absorption or large source-detector separation. In these regimes the noise can cause the gradient of χ² to become discontinuous and complex, hindering retrieval of optical properties. Our simulation generates a large histogram of different but strongly correlated signals, differing in remission position, photon arrival time and acceptance angle. We apply singular value decomposition (SVD) to derive a low-rank-approximation of the lookup table. SVD helps us to harness the correlated signals, while rejecting uncorrelated noise. We found this approach to reduce noise and improve smoothness of χ²-planes, while preserving all features of the simulations exceeding noise-level. To enforce the smoothness of the χ²-planes we removed remaining noise in the singular vectors by a Savitzky-Golay-filtering. In contrast to the filtering of the whole high-dimensional lookup table, smoothing of a few singular vectors can be done in a mild, supervised way. As an additional benefit, the low rank approximation dramatically reduces the amount of memory needed to handle the table. This became especially important when treating lookup tables of high dimensionality created in multilayer simulations. Furthermore evaluation of interpolated MC-curves for intermediate optical properties and detector positions is simplified since it can be performed on the few singular vectors instead of the whole table.

The literature is replete with preclinical and some clinical studies showing the utility of fluorescence guided surgery with fluorescence images reported in “arbitrary units” or (AUs) that can vary with radiometric set-up, tissue optical properties, and agent characteristics. Despite several attempts, it is highly unlikely that AUs can be reliably and routinely calibrated to international standard units (SI units) that is reflective of the amount of probe distributed within tissues. Perhaps more concerning is that there is no industry standard or radiometric performance criteria for preclinical or clinical fluorescence imaging devices, even though IEC 60601, an international series of technical standards, requires numerical indications of performance of medical devices to be in SI units or SI-units for traceability. Using stable phantoms developed by us and our colleagues at NIST1, we have devised approaches to use radiometric principles to qualify device performance and calibrate image output in terms of SI units. In this presentation, we review the performance of marketed clinical devices as reported in SI units and compare SI-derived metrics of commercially available fluorescence imaging devices. Clearly, the efficacy of a fluorescence molecular imaging agent is critically dependent upon the performance of an imaging device and the future success of fluorescence guided surgery depends critically upon community and industry adoption of performance standards for devices. 1Zhu, B., Rasmussen, J.C., Litorja, M., and E.M. Sevick-Muraca, “Determining the performance of fluorescence imaging devices using traceable working standards with SI units of radiance,” IEEE Trans. Med. Imaging, 35(3): 802-11, 2016, PMID: 26552078

Infrared thermographs (IRTs) have been implemented for mass fever screening in public areas such as airports during outbreaks of infectious disease pandemics such as Ebola virus disease, yet the approach has not been entirely successful. There has been increasing evidence in the literature that IRTs can provide greater accuracy in estimating core body temperature, if qualified systems are used and appropriate procedures are consistently applied. In this study, we addressed the issue of system qualification by implementing and evaluating a battery of test methods for objective and quantitative performance assessment of two commercial IRTs based on a recent international standard (IEC 80601-2-59). We evaluated stability and drift, image uniformity, minimum resolvable temperature difference, and measurement accuracy of the IRTs and illustrated how experimental and data processing procedures affect results. For instance, we demonstrated that offset temperature compensation, achieved using an external blackbody, is essential to meet the standard’s recommendations for temperature drift and stability. Additionally, we identified methods that can be implemented to optimize IRT evaluation. As an example, we identified a less burdensome approach to characterize image uniformity with a single image acquisition of a uniform blackbody. Overall, the insights into thermograph standardization and acquisition methods provided by this study may improve the utility of this technology and aid in comparing IRT performance, thus improving the potential for high quality disease pandemic countermeasures.

The fluorescents detector sub-system is one of most important sub-systems of fluorescence-activated cell sorting (FACS) flow cytometry. The Photomultiplier Tube (PMT) detector sub-system are used in the fluorescent detection of Becton Dickinson (BD) AccuriTM C6 Plus. For using cost effective solid-state detectors (SSD) sub-system, we have validated SSD sub-system as the replacement sub-system of PMT. BD Bioscience and Pavilion Integration Corporation (PIC) use BD Instruments (Accuri C6 Plus) as test tools to test the SSD of PIC vs. PMT. We further ran the Swap test and Repeatability as well as ran test at the operational temperature range of cytometer. We also ran the Linearity test. All results were passed. Based on these results, BD Bioscience teams will run the biological sample testing to cover the test of CFSE- Proliferation Assay, Cell Cycle Analysis, and Apoptosis.

Obtaining a sharp and focused image is essential to fully utilize the advantages of hyperspectral imaging. For line scanning hyperspectral devices, focusing is a challenge in applications where the height and/or position of the imaged object might vary during a scan. Initial focusing is in addition a tedious process that has to be repeated for each sample or measurement. In this paper, a new continuous autofocus tracking system for hyperspectral line-scanning cameras is reported. The presented system is able to automatically and objectively find the correct distance between the camera and the imaged object for proper focus, and retain this focus distance during scan using a laser triangulation system. Concurrent with the focusing, a 3D model of the object is constructed. The system was tested and found to perform well for NIR-SWIR imaging of human hands and test objects with sharp changes in height and contrast. The method is easily adaptable to other spectral ranges and applications, such as industrial conveyor belt applications. The method significantly eases the acquisition of hyperspectral images by ensuring optimal image quality in every scan and eliminating the need for manual refocusing between individual samples.

Radiochromic films are commonly used in radiation therapy dosimetry and quality assurance. However, their spectral response is studied only for a limited set of beam qualities used in radiation therapy. In this work, we investigate the spectral response of the EBT3 radiochromic films for a broad range of megavoltage photon and electron radiation beam qualities. Dose, dose rate, and inter-batch dependencies are investigated. For beam qualities studied in this work, we found that for a given batch, the spectral response of the EBT-3 radiochromic films is beam quality and dose-rate independent. However, the spectral response of the films is batch-dependent.

In this research we outline the optical background and manufacture of the OPTA device: an Optical Probe to evaluate Tissue Atrophy. We present a portable profiling system capable of directly interrogating the integrity of human skin in vivo. The device utilizes laser speckle and spectral imaging modalities to measure a suite of physical parameters to aid clinical assessment, in particular surface roughness and blood oxygenation. We provide a detailed discussion on the relation between laser speckle scattering and the influence of surface texture. This leads us to discuss how these measurements can relate a participant’s perception of skin pathologies in vivo and discuss the potential clinical application. We will first discuss the technical information relating to the design and assembly of the Optical Probe to evaluate Tissue Atrophy (OPTA) probe, utilizing a biocompatible 3D printing material, polymer optical fibers and custom miniature cage system optics. Finally, we will present the practical use of this device using our results of a pilot study to trial the OPTA device, in house.

Optical oxygen detection in humans is a well-established technology commonly used in different fields, such as research, diving, and healthcare, among others. For measurements in humans, oxygen sensors can be calibrated easily and put on the patient for extended periods of time. For measurements in other species, like marine mammals, existing technologies are inadequate. Management of oxygen stores is a key physiological process that dictates the breath-hold ability of marine mammals. Understanding this physiological specialization is an area of active research that could frame how protected species function within their marine ecosystems, and unlock new therapies to mitigate low oxygen injury in humans. In the present work, we addressed the technology gap by developing an implantable, minimally-disruptive optical oxygen sensor that is encased in a biocompatible soft elastomer. The mechanical properties of the elastomer were tailored to make it elastic, and resistant to rupture. This material is expected to pose less interference in normal muscle movements than a stiff sensor, and is, therefore, more suitable for extended at-sea deployments in marine mammals. The optical components encased in the elastomer are two multiwavelength LEDs and a silicon photomultiplier detector. Different elastomers were tested as biocompatible encasings for the sensor. Among the evaluated parameters were: cell viability, inflammatory response, biodegradability, temperature stability, electroconduction, mechanical properties, and oxygen levels in ex- and in vivo models. In summary, we have developed a biocompatible, implantable, minimally-disruptive, stable optical oxygen sensing probe for studying management of oxygen in the muscle of free diving marine mammals.

To unlock the massive economic and clinical potential of the biophotonics research field several barriers to market must be overcome. The National Centre for Healthcare Photonics, set up in 2018 at NETPark, UK, is an £18 million centre dedicated to supporting companies of all sizes in translating research into commercial products. This presentation will detail case studies demonstrating effective partnerships between local companies, non-governmental organisations and universities to bring healthcare products utilising photonics to market more effectively. A dedicated project, Spotlight, funded by the ERDF, provides healthcare photonics SMEs and start-ups with funded support including staff time from Durham University and the Centre for Process Innovation (CPI), an organisation specialising in supporting the development of next-generation manufacturing organisations. Examples of support that Spotlight offers include: - access to lab space and state-of-the-art research facilities; - proof-of-concept research; - system design, prototyping and validation activity; - manufacture of equipment for clinical investigation; - regulatory compliance support; - health economics modelling - commercialisation support; - pathways to generating clinical evidence. Typically, the SMEs that partner with Spotlight have expertise in several areas and research fields but lack either photonics expertise or access to photonics equipment and do not have the scale or resources to obtain these feasibly. We will present examples of SMEs that have received assistance from Spotlight to enable commercial translation of research. Examples are taken at different stages of product development and different biophotonics technologies and demonstrate the success of interdisciplinary academic-industry partnerships in translating research to market.

In the clinically relevant field of tissue oximetry, there is an urgent need to develop phantom-based methods for validation. Physical phantom approaches based on solid or liquid turbid media containing hemoglobin with variable oxygenation have limited capabilities to represent real tissues regarding optical properties, structure and variability. Digital phantoms are an alternative with high flexibility. Rather than physically simulating the process of light propagation, they provide the detector with light signals mimicking the signals detected in vivo. We present a technique to produce digital phantoms for time-domain diffuse optical spectroscopy that mimic arbitrary photon time-of-flight distributions (DTOFs) by creating a time-dependent attenuation. The setup contains a spatial light modulator (SLM) and a set of optical fibers of different lengths corresponding to a stepwise delay. The light pulse entering the arrangement is spatially dispersed and illuminates the SLM which controls the intensity at each pixel. The SLM array is imaged onto the entrance faces of the delay fibers. The amount of photons received by each individual fiber can be adjusted. Finally, the light transmitted through all fibers are combined and fed to the detector of the timedomain instrument under test. In this way, DTOFs of any desired shape can be obtained. For first proof-of-principle experiments to demonstrate the general feasibility of the concept we used a liquid-crystal SLM and a set of four graded-index fibers differing in length by about 100 mm. The tests were performed with a timedomain instrument based on time-correlated single photon counting, with picosecond diode and supercontinuum laser sources and a single-photon avalanche diode as well as a hybrid photomultiplier as detectors. This large separation in fiber lengths allowed the performance regarding amplitude and temporal shape to be assessed for each delay independently. The generation of arbitrary DTOFs was simulated by realizing various patterns of target amplitudes. Temporal position and width of the measured pulse profiles for all fibers were in agreement with the expectations. Amplitude linearity was reasonable while the contrast between highest and lowest amplitude values was not yet satisfactory. Steps of further development are discussed.

Cerebral oximetry based on near-infrared spectroscopy (NIRS) has seen increasing clinical use for monitoring of premature infants as well as during neonatal, pediatric and adult cardiac surgery. One key confounding factor and a likely contributor to observed inconsistency amongst commercial NIRS oximeters is skin pigmentation. Clinical studies have shown negative bias in oxygen saturation (StO2) with increasing melanin content. In prior work, we developed a cerebral oximetry phantom comprised of a 3D-printed channel array module representing brain tissue and molded silicone layers simulating extracranial regions. The purpose of the current study was to develop and test epidermis-simulating layers that exhibit realistic human pigmentation properties. Initially, we performed spectroscopic characterization of potential melanin simulating agents – including coffee, India ink, synthetic melanin, and water-soluble nigrosin – in a polydimethylsiloxane (PDMS) substrate. We determined that the NIR absorption spectrum of water-soluble nigrosin most accurately matched human melanin. Layers of 0.1 mm thickness were fabricated with different nigrosin concentrations to simulate epidermis with light, moderate, and dark pigmentation. The brain module channels were filled with bovine blood in the 30-100% oxygenation range and measurements performed with neonatal/pediatric probes from commercially available cerebral oximeters. We found that StO2 reported by the oximeters decreased monotonically with increasing pigmentation level. The magnitude of this impact increased with decreasing StO2, producing a maximum change in saturation of approximately 8%. The consistency of our results with prior clinical findings provides preliminary evidence of the utility of our approach for assessing the impact of epidermal melanin in phantom-based performance testing.

Multimodal endoscopy, with fluorescence labeled peptides specific for multiple biomarkers, is a promising technique to detect early-stage GI tract cancers in vivo. A reproducible bile duct phantom with near infrared (NIR) fluorescent targets is developed for practicing the clinical study protocol and quantitative evaluation of multimodal endoscope performance during biliary duct imaging. Furthermore, this phantom with strictures will be used for testing new fluorescence guided biopsy devices. Materials and Methods: A soft, flexible synthetic human bile duct was fabricated from a paintable silicone rubber. Due to the complex structure of biliary system (such as hepatic ducts, cystic duct, and common bile duct), the template mold for lumen was designed for 3D printing using Polyvinyl Acetate (PVA), which can be later dissolved in water. Cured gelatin patches with different concentrations of fluorescence dyes (Cy5 and IRDye800) were placed onto the mold. Then silicone rubber with pigments to simulate visual appearance was painted in layers. After the silicone curing, the phantom was placed in warm water (40 degreeC) to dissolve PVA. Two different multimodal scanning fiber endoscope systems, RGB reflectance + NIR fluorescence and 3 fluorescence (IRDye800, Cy5, and FITC) + grayscale reflectance, were used to test the phantom. Results: The bile duct phantom is flexible, stable, and repeatable to fabricate with strictures. Clinical study procedures of fluorescence labeling were evaluated quantitatively. The NIR fluorescence targets in the phantom were used to calibrate the imaging system, further develop image-based biomarker quantification.

Biomedical optical systems and models can be easily validated by the use of tissue-simulating phantoms. They can consist of water-based turbid media which often include inks (India ink and molecular dyes) as absorbers. Optical stability of commonly exploited inks under the influence of light, pH changes and the addition of TiO₂ and surfactant, was studied. We found that the exposure to ultraviolet and visible light can crucially affect the absorption properties of molecular dyes. On average, absorption peaks decreased by 47.3% in 150 exposure hours. Furthermore, dilution can affect ink’s pH and by that, its decay rate under light exposure. When TiO₂ was added to the phantoms, all molecular dyes decayed rapidly. Photocatalytic nature of TiO₂ can be partially avoided by selecting TiO₂ with surface and crystal structure modification. Surfactant, normally present in the phantoms with polystyrene spheres, can cause absorption peak shifts up to 20 nm and amplitude changes of 29.6%. Therefore, it is crucial to test the optical stability of inks in the presented manner before their exploitation in water-based phantoms.

Indirect digital X-ray scintillator has been widely used in various medical radiographic and diagnostic applications. To get a clear detection image for precise diagnosis with minimizing the X-ray radiation exposure to the patients, high performance X-ray scintillator is required. The double layer scintillator with having diffuse reflection layer is growing interest composed of highly-scattering scintillator particles are on top of the scintillator. However, since few researches has been studied for the scintillator, the analytic model for expecting and analyzing the scintillator performance is required. Here, we propose the analytic model for expecting the energy efficiency of the granular X-ray double layer scintillator, which is well matched with Monte-Carlo simulation in accuracy of 98%. And furthermore, we suggest the design strategy for achieving high energy efficiency with the satisfaction of sufficient spatial resolution and the design parameters, such as particle size and the thickness of the each layer, are determined. Compared with the Monte Carlo calculation time, our analytical calculation took time only half second, which was 40,000 times faster. Our simple, efficient analytic model has an impact that expectation of energy efficiency in X-ray double layer scintillator can be fulfilled easily without losing accuracy. Furthermore, various cases of design parameters can be tested in advance with the model before manufacturing and designing the X-ray scintillator devices.

Vascular phantoms are crucial tools for clinical training and for calibration and validation of medical imaging systems. With current methods, it can be challenging to replicate anatomically-realistic vasculature. Here, we present a novel method that enables the fabrication of complex vascular phantoms. Poly(vinyl alcohol) (PVA) in two forms was used to create wall-less vessels and the surrounding tissue mimicking material (TMM). For the latter, PVA cryogel (PVA-c) was used as the TMM, which was made from a solution of PVA (10% by weight), distilled water, and glass spheres for ultrasonic scattering (0.5% by weight). PVA-c is not water soluble, and after a freeze-thaw cycle it is mechanically robust. To form the wall-less vessels, vessel structures were 3D printed in water-soluble PVA and submerged in the aqueous solution of PVA-c. Once the PVA-c had solidified, the 3D printed PVA vessel structures were dissolved in water. Three phantoms were created, as initial demonstrations of the capabilities of this method: a straight vessel, a stenosed (narrowed), and a bifurcated (branched) vessel. Ultrasound images of the phantoms had realistic appearances. We conclude that this method is promising for creating wall-less, anatomically realistic, vascular phantoms.

Optical coherence tomography (OCT) is one of useful diagnostic devices for retinal diseases. Recently, optical coherence tomography based angiography (OCTA) extends the OCT applications from structural images to functional images by enabling blood vessel networks mapping. As the use of OCT and OCTA increases in ophthalmology, it is necessary to develop retinal phantoms for performance evaluation of clinical OCT devices for retinal imaging. In this study, we have developed a retinal layer-mimicking phantom including microfluidic channels to assess OCT and OCTA image quality and to evaluate software accuracy. The phantom is constructed of thin scattering films based on polydimethylsiloxane (PDMS) and titanium dioxide (TiO2) powder. We adjusted TiO2 particle concentration in PDMS for matching intensity of retinal OCT images. Particles were well dispersed throughout PDMS using a probe tip sonicator. Mixed PDMSs were carried out spin coating on a glass slide to make thin films. Before spin coating, silane was applied to the glass substrate to provide a hydrophobic coating for easily removing of cured PDMS. After spinning, thin filmed PDMSs were cured. Microfluidic channels were also made with PDMSs mixed with TiO2 powder, and were designed with sizes of 50 um, 100 um, and 200 um. thin films of cured PDMS were stacked on microfluidic channels. We used diluted dye liquids containing microbeads to occur optically scattered liquid flow like blood vessel. Dye liquids containing microbeads were flowed into an inlet port of the channel through a syringe pump Finally, we successfully obtained cross-sectional volumetric OCT and OCTA images of completed retinal phantom using lab-made OCT system and clinical OCT system.

Supercontinuum sources are increasingly applied to spectral domain optical coherence tomography (OCT) due to their high power across octave-spanning bandwidths from the visible to the mid-infrared, enabling ultra-high resolution imaging with great flexibility in choice of operating wavelength region [1]. However, one of the main drawback of supercontinuum sources in OCT imaging is the large pulse-to-pulse fluctuations which often acts as the limiting factor in terms of sensitivity rather than the shot noise [2]. The theoretical noise description widely used by the OCT community assumes that the light source operation is based on spontaneous emission, which is not the case for supercontinuum laser source [3]. As a result, the optimal operating conditions must be evaluated experimentally without a reliable prediction [2,4]. Without a reliable theoretical noise model, optimization can be challenging. We present a new and simple noise model that allows prediction of the noise performance of an OCT system driven by a supercontinuum sources, without any assumptions regarding the type of light source. We show that the predictions are in excellent agreement with the experimental results obtained by employing a widely used commercial supercontinuum source. We further investigate the shape of the noise floor in an A-scan obtained with a commercial supercontinuum source, which is not flat, as expected for shot-noise limited light sources. We demonstrate that this shape is predicted solely by the spectral correlations of the supercontinuum, which therefore must be taken into account when characterizing the sensitivity of the OCT system driven by a supercontinuum source. [1] Israelsen, N.M., Maria, M., Mogensen, M., Bojesen, S., Jensen, M., Haedersdal, M., Podoleanu, A., and Bang, O., “The value of ultrahigh resolution OCT in dermatology - delineating the dermo-epidermal junction, capillaries in the dermal papillae and vellus hairs,” Biomedical Optics Express 9(5), 958–963 (2018). [2] Maria, M., Bravo Gonzalo, I., Feuchter, T., Denninger, M., Moselund, P.M., Leick, L., Bang, O., and Podoleanu, A., “Q-switch-pumped supercontinuum for ultra-high resolution optical coherence tomography,” Optics Letters 42(22), 4744–4747 (2017). [3] Dudley, J.M., Genty, G., and Coen, S., “Supercontinuum generation in photonic crystal fiber,” Reviews of Modern Physics 78(4), 1135–1184 (2006). [4] Yuan, W., Mavadia-Shukla, J., Xi, J., Liang, W., Yu, X., Yu, S., and Li, X., “Optimal operational conditions for supercontinuum-based ultrahigh-resolution endoscopic OCT imaging,” Optics Letters 41(2), 250 (2016).

Intraocular pressure is very significant in ophthalmology and it is used to diagnose glaucoma. It is usually estimated by a tonometer based on the Imbert-Fick law. However, systematic investigation for the effect of the geometrical and mechanical characteristics of eye phantom on the validity of the tonometer pressure is rare. We fabricated polydimethylsiloxane eye phantoms of which 3-D geometries based on Archimedes principle and mechanical properties were tailored to those properties of human eye and applied to evaluate the validity of tonometer pressure. The shell thickness at the center as well as the mechanical modulus was controlled by the concentration of ethylene glycol and the formulation of PDMS, respectively. Optical coherence tomography and tonometer were used to determine the detailed geometrical information of eye phantom and tonometer pressure, respectively. The thickness of the shell at the centre of eye phantom could be varied from 0.2 mm to 1.0 mm with different modulus. The range of eye phantom properties is comparable to the typical values of the modulus and the thickness of human eye of 0.4 MPa and 0.52 mm, respectively. The tonometer pressure was found to be dependent on the shell thickness as well as the modulus of the shell. We have successfully developed eye phantoms for evaluating the validity of tonometer pressure. The values measured from eye phantoms are similar to the typical IOP of human eye if the modulus and thickness of the shell are similar to those of human eye.

This work describes a procedure to characterize a developed acousto-optic tunable filter (AOTF) based hyperspectral imaging (HSI) system, operating in the visible-near infrared (VNIR) spectrum. The developed AOTF-HSI system consists of an AOTF (11 × 12 mm aperture), a set of optics, and a computer. The AOTFHSI setup includes a complementary metal oxide semiconductor (CMOS) camera (2048 x 2048 pixels), a zoom lens (55–250 mm f/4–5.6), and an AOTF radio frequency synthesizer. Two multifaceted reflector tungstenhalogen lamps (150 W) were used to provide double-sided illumination to the region of interest. Image acquisition was accomplished by a home-made C# code. The code enables imaging of samples in the VNIR (450 – 850 nm) range in both hyper/multi-spectral modes. The developed spectral imager presents a valuable opportunity for noninvasive evaluation of medical samples.

Functional Near-infrared Spectroscopy (fNIRS) is an optical brain imaging technology based on mapping blood oxygenation levels on the cortical surface of the brain. fNIRS has the potential to become a point-of-care brain monitoring system for localized brain measurements in various medical conditions including brain injury and concussion. Although fNIRS electronic circuit has been miniaturized significantly, one of the least elucidated elements of the portable fNIRS systems is the process for developing optodes (light sources and detectors) for the improvements in skin-optode coupling, signal-to-noise ratio (SNR), user’s comfort-level and motion artifact reduction. We have used modern design tools such as 3D printing and laser cutting to fabricate human-centered fNIRS optodes. Feedback was taken from participants of different groups throughout the iterative design process of data collection. Two types of fNIRS optodes were designed; one was based on forehead patch and the other was integrable into an electrode head cap. The optodes were connected to our developed portable fNIRS hardware. The noise characteristics of the optodes for the long-term brain imaging settings, while subjects were performing physical activities, was systemically studied in each of the iterations and designs. The final front-end hardware design was tested on eight subjects with varying head size, shape and skin tone. Experimental results of SNR and resistance to the motion artifacts show that 3D printing can be effective for the development of fNIRS optode. These fNIRS optodes prove to not only be easy to use and comfortable but also capable of acquiring the fNIRS signal with other brain monitoring modalities such as electroencephalography (EEG).