Near-infrared optical imaging holds a promise as a noninvasive technology toward cancer diagnostics and other tissue imaging applications. In recent years, hand-held based imagers are of great interest toward the clinical translation of the technology. However hand-held imagers developed to date are typically designed to obtain surface images and not tomography information due to lack of coregistration facilities. Herein, a recently developed hand-held probe-based optical imager in our Optical Imaging Laboratory has been implemented with novel coregistration facilities toward real-time and tomographic imaging of tissue phantoms. Continuous-wave fluorescence-enhanced optical imaging studies were performed using an intensified charge coupled device camera based imaging system in order to demonstrate the feasibility of automated coregistered imaging of flat phantom surfaces, using a flexible probe that can also contour to curvatures. Three-dimensional fluorescence tomographic reconstructions were also demonstrated using coregistered frequency-domain measurements obtained using the hand-held based optical imager. It was also observed from preliminary studies on cubical phantoms that multiple coregistered scans differentiated deeper targets (approximately 3 cm) from artifacts that were not feasible from a single coregistered scan, demonstrating the possibility of improved target depth detectability in the future.
"This allows potential early stage tumor diagnosis, especially upon using external fluorescent contrast agents. Currently, work is carried out to register the positional information of the Gen-2 hand-held probe during imaging , such that 3D tomographic imaging can also be performed. "
[Show abstract][Hide abstract] ABSTRACT: Hand-held near-infrared (NIR) optical imagers are developed by various researchers towards non-invasive clinical breast imaging. Unlike these existing imagers that can perform only reflectance imaging, a generation-2 (Gen-2) hand-held optical imager has been recently developed to perform both reflectance and transillumination imaging. The unique forked design of the hand-held probe head(s) allows for reflectance imaging (as in ultrasound) and transillumination or compressed imaging (as in X-ray mammography). Phantom studies were performed to demonstrate two-dimensional (2D) target detection via reflectance and transillumination imaging at various target depths (1-5 cm deep) and using simultaneous multiple point illumination approach. It was observed that 0.45 cc targets were detected up to 5 cm deep during transillumination, but limited to 2.5 cm deep during reflectance imaging. Additionally, implementing appropriate data post-processing techniques along with a polynomial fitting approach, to plot 2D surface contours of the detected signal, yields distinct target detectability and localization. The ability of the gen-2 imager to perform both reflectance and transillumination imaging allows its direct comparison to ultrasound and X-ray mammography results, respectively, in future clinical breast imaging studies.
") using MATLAB/LabVIEW software developed in house . An acoustic tracker is implemented on the probe head to enable real-time tracking of the 3D position and orientation of the probe (in six degrees of freedom) with respect to the phantom surface (Step #1). "
[Show abstract][Hide abstract] ABSTRACT: Optical imaging is emerging as a non-invasive and non-ionizing method for breast cancer diagnosis. A hand-held optical imager has been developed with coregistration facilities towards flexible imaging of different tissue volumes and curvatures in near real-time. Herein, fluorescence-enhanced optical imaging experiments are performed to demonstrate deeper target detection under perfect and imperfect (100:1) uptake conditions in (liquid) tissue phantoms and in vitro. Upon summation of multiple scans (fluorescence intensity images), fluorescent targets are detected at greater depths than from single scan alone.
"However , the noise from the background signal dominated the image, and a target was not detected even after subtracting the excitation background signal. On applying our multilocation scanning approach, the targets were differentiable under imperfect uptake conditions (i.e., T:B = 100:1) . In addition to fast 2D imaging, the handheld device described here has demonstrated 3D tomography of fluorescent targets with tissue phantoms using frequency-domain–based measurements to estimate the 3D location and volume of the target within the tissue . "
[Show abstract][Hide abstract] ABSTRACT: Near-infrared (NIR) optical imaging is a noninvasive and nonionizing modality that is emerging as a diagnostic tool for breast cancer. The handheld optical devices developed to date using the NIR technology are predominantly developed for spectroscopic applications. A novel handheld probe-based optical imaging device has been recently developed toward area imaging and tomography applications. The three-dimensional (3D) tomographic imaging capabilities of the device have been demonstrated from previous fluorescence studies on tissue phantoms. In the current work, fluorescence imaging studies are performed on tissue phantoms, in vitro, and in vivo tissue models to demonstrate the fast two-dimensional (2D) surface imaging capabilities of this flexible handheld-based optical imaging device, toward clinical breast imaging studies. Preliminary experiments were performed using target(s) of varying volume (0.23 and 0.45 cm(3)) and depth (1-2 cm), using indocyanine green as the fluorescence contrast agent in liquid phantom, in vitro, and in vivo tissue models. The feasibility of fast 2D surface imaging ( approximately 5 seconds) over large surface areas of 36 cm(2) was demonstrated from various tissue models. The surface images could differentiate the target(s) from the background, allowing a rough estimate of the target's location before extensive 3D tomographic analysis (future studies).
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.