A Gen-2 Hand-Held Optical Imager: Phantom and preliminary in-vivo breast imaging studies

Diffuse optical imaging is a promising noninvasive and non-ionizing modality for breast cancer diagnosis. Hand-held optical imagers are developed toward rapid clinical translation due to their portability and patient-comfort. In our Optical Imaging Laboratory, a Gen-2 hand-held optical imager has been developed capable of two-dimensional (2D) and three-dimensional (3D) imaging, and has a flexible probe head designed to contour to different breast tissue curvatures. The optical imager is composed of an intensified charge-couple device (ICCD) based detector, and six 785nm laser diodes (connected the probe heads via optical fibers). Herein, phantom studies were performed in order to validate the target detection capabilities of the imager. Experimental studies using slab phantoms demonstrated that the imager can detect targets up to 2.5 and 5 cm deep via reflectance and transmission measurements, respectively. In addition, resolution studies have demonstrated the ability of the system to resolve two 0.95cm diameter targets, placed 0.5cm apart and at a depth of 2cm. Preliminary in-vivo breast imaging studies have been carried out on healthy human subjects. These studies have demonstrated that targets can be detected by varying the pressure applied during imaging with superficially placed target(s) in the intra-mammary fold.