Three-dimensional modelling of light scattering in biological tissue by the spectral method

For the first time the three dimensional modelling of laser light scattering in biological tissue has been performed using the spectral technique. The accuracy of the spectral numerical method has been verified hy comparison with linear perturbation theory and Mie theory. Comparison with Mie theory has validated that the three-dimensional scaler wave equation is a good approximation to the full Maxwell's set of equations for light scattering: at moderate angles. The computational requirements for the spectral method in modelling laser interaction with biological samples are much lower than the requirements for other existing numerical methods: finite-difference time-domain and Monte Carlo. Yet the new algorithm is capable of resolving the variations in the scattered signal with a Contrast in intensity of up to six orders of magnitude. The spectral technique carl be successfully applied to address scattering from individual cells and from biological samples containing many cells. The new method is well suited to recognize the size and composition of biological cells, making it a valuable tool in cell cytometry, for example. in the detection of rare event cells and cancerous cells.