Time-sliced, two-dimensional, near-infrared imaging of normal and malignant human breast tissues

Summary form only given. Development of optical modalities for screening of breast cancer is an intensely pursued area of contemporary research. Here, the authors present the initial results of a time-sliced transillumination imaging approach to image and distinguish between normal and cancerous regions of in vitro breast tissue samples. The approach uses optimal picosecond-scale slices of the transmitted light pulse to form images. The experimental arrangement used 800 nm, approximately 130-fs duration, l-kHz repetition-rate pulses with 400-mW average beam power from a Ti:sapphire laser system for transillumination imaging. The beam was expanded by a beam expander, and a 3-cm diameter central part of it was selected out using an aperture to illuminate the sample. Time slicing was accomplished using a gated image intensifier coupled to a charge-coupled device (CCD) camera system that provided an electronic gate pulse whose duration (full width at half maximum) could be adjusted to a minimum of 80 ps and the position could be varied in steps of 25 ps over a 15-ns range. The time-sliced image was recorded by the CCD camera and displayed on a personal computer. The breast tissue sample consisted of a cancerous piece placed between two normal pieces of 5-mm nominal thickness and lateral dimensions between 8-14 mm. The pieces were compressed between two glass plates to provide uniform thickness and good physical contact between the adjacent pieces of tissue. The tissues obtained from National Disease Research Interchange came from the left breast of a 61-yr-old female patient.