Abstract

Time-sliced and spectroscopic imaging approaches were used to obtain two-dimensional (2-D) transillumination images of a composite in vitro human breast tissue sample comprising cancerous and normal fibrous tissues, adipose tissues, and a lymph node. Time-sliced imaging approach used 800-nm, approximately 130-fs duration, 1 kHz repetition-rate pulses from a Ti:sapphire laser system to illuminate the sample, and a gated imaging system that provided a variable-position, ~80 ps-duration electronic gate to record time-sliced 2-D images. Images recorded with earlier temporal slices (approximately, first 100 ps) of the transmitted light highlighted the lymph node and cancerous tissues, while the later slices (later than 300 ps) accentuated the adipose and normal tissues. Spectroscopic imaging arrangement made use of 1225 - 1300 nm light from a chromium-doped forsterite laser for sample illumination, a Fourier space gate and a polarization gate to sort out a fraction of the image-bearing photons, and an InGaAs area camera for recording 2-D images. Marked enhancement of image contrast between the adipose tissue and other tissues in the specimen was observed when the wavelength of imaging light was near resonant with the 1203-nm optical absorption resonance of the adipose tissue. Wavelength-dependent differences in relative light transmission through the normal and cancerous tissues were observed.

© 2000 Optical Society of America