A Multiscale Approach to Terahertz Electric Field Estimation in Corneal Tissues

Computational dosimetry is the main approach to electric field estimation for radiation-safety regulation and treatment design when no measurements of fields within the body are possible. At high frequencies such as THz, the electromagnetic fields are absorbed at the body surface (exposed skin or the cornea of the eyes). New safety studies require not only the estimation of the average electric field intensity within the superficial tissue, but also the possible localization or concentration of electric fields due to inhomogenities in the microstructure of the tissue such as cellular membranes, which can be of importance in microthermal or nonthermal effects on cells. A direct numerical modeling with all fine structure suffers from the problem of dimensions: the source is at the scale of the whole tissue, whereas fine electric field distributions are required at the cell scale of several micrometers. In this article, a multiscale approach is formulated to efficiently estimate the induced field distributions at tissue and cellular scales. Estimation of the electric fields in the corneal tissue is then solved and discussed with numerical results. It is seen that mild localizations at the microscale are possible.