Tumor contrast in time-domain, near-infrared laser breast imaging

The contrast of breast disease in an image produced by a time-domain, near-infrared laser, imaging system was calculated by use of a finite-difference method. The contrast was investigated for tumors of different sizes, in a range of positions within the breast, and in a range of breast thicknesses. Contrast is greatest for large tumors that are near the breast surfaces and that are measured at short times of flight. The contrast was shown to increase as the scattering and the absorption properties of the tumor increased. The scattering properties of the tumor were shown to make the biggest contribution to the contrast at short times of flight. Both pointlike and large extended source and detector configurations were investigated. The effect of the system size on the signal-to-noise ratio was investigated.