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Fiber-free non-contact near-infrared (NIR) imaging devices using wide-field detectors are emerging apart from the contact and fiber-based NIR devices. Unlike the fiber-based devices that can image deep tissues, the fiber-free noncontact devices have been used only for subsurface imaging (≤1 cm) to date. A new compact (7 × 8 × 12 cm3) handheld Near-Infrared. Optical Scanner (NIROS) has been developed for fiber-free non-contact imaging of deep tissues in both reflectance and transmittance modes. Absorption-contrasted diffuse imaging studies were performed on tissue mimicking cubical phantoms (5.5 × 5.5 × 5.5 cm3 volume) using India. Ink based targets located at various depths (0.5 to 4 cm) in both reflectance and transmittance modes. Preliminary in vivo breast imaging studies in transmittance mode were also performed to determine the deep target detectability of NIROS. The hand-held NIROS could detect targets up to 1.5 cm in reflectance mode and across the entire depth of the phantom (4 cm deep) in transmittance mode, as observed from phantom studies. Absorption-contrasted targets placed as deep as 6 cm were detectable in vivo breast tissues during transmittance imaging, when comfortable pressure was applied via compression. The non-contact hand-held NIROS demonstrated the ability to detect targets deeper than 1 cm (which was the limit attempted to date using other non-contact NIR devices in phantoms or in vivo). The ability of the portable handheld NIROS to perform deep tissue imaging can allow for in vivo breast imaging studies in the future, with a potential as an initial assessment tool for breast cancer pre-screening.

A generation-2 (Gen-2) handheld optical imager capable of two-dimensional surface and three-dimensional tomographic imaging has recently been developed. Herein, the ability of the handheld imager to detect and resolve two targets under diffuse and fluorescence imaging conditions has been demonstrated via tissue phantom studies. Two-dimensional surface imaging studies demonstrated that two 0.96 cm diameter Indocyannine Green targets were detected and resolved ~0.5 cm apart (between edges) at a target depth of 1 cm during diffuse imaging and up to 2 cm depth during fluorescence imaging. Preliminary 3D tomographic imaging capability to resolve the two targets was also demonstrated, but requires extensive future studies.

A Gen-2 hand-held optical imager has been developed capable of 2D surface imaging and 3D tomography. In the current work, the capability of the imager to resolve two closely placed targets is assessed via 2D and 3D tomographic studies. Resolution studies have been carried out under various experimental conditions using slab phantoms. Preliminary 2D surface images of reflected measurements have demonstrated the ability of the system to resolve 0.95cm diameter targets placed 0.5cm apart at 2cm depth. Three dimensional tomography reconstructions are currently performed to assess the resolution capacity under different experimental conditions.

A novel Gen-2 hand-held optical imager was developed with capabilities to contour to different tissue curvatures, perform simultaneous illumination and detection and imager large tissue surfaces. Experimental studies using cubical phantoms demonstrated that the imager can detect targets up to 2.5 cm and 5 cm deep via reflectance and transmission measurements, respectively. The target was also localized as regions of high absorption during multi-scan imaging of curved breast phantoms via both reflectance and transmission modes. Preliminary in-vivo breast imaging demonstrated that the target can be detected via varying the pressure applied during imaging, as observed from reflectance-based imaging studies on healthy adults with superficially placed target(s) in the intra-mammary fold.

Near-infrared (NIR) optical imaging modality is one of the widely used medical imaging techniques for breast cancer imaging, functional brain mapping, and many other applications. However, conventional NIR imaging systems are bulky and expensive, thereby limiting their accelerated clinical translation. Herein a new compact (6 × 7 × 12 cm3), cost-effective, and wide-field NIR scanner has been developed towards contact as well as no-contact based real-time imaging in both reflectance and transmission mode. The scanner mainly consists of an NIR source light (between 700- 900 nm), an NIR sensitive CCD camera, and a custom-developed image acquisition and processing software to image an area of 12 cm2. Phantom experiments have been conducted to estimate the feasibility of diffuse optical imaging by using Indian-Ink as absorption-based contrast agents. As a result, the developed NIR system measured the light intensity change in absorption-contrasted target up to 4 cm depth under transillumination mode. Preliminary in-vivo studies demonstrated the feasibility of real-time monitoring of blood flow changes. Currently, extensive in-vivo studies are carried out using the ultra-portable NIR scanner in order to assess the potential of the imager towards breast imaging..