Assessment of Signals from a Tissue Phantom Subjected to Radiation Sources of Temporal Spans of the Order of a Nano-, Pico-, and Femto-Second—A Numerical Study

Abstract

This article reports and analyzes signals originating from a human tissue phantom subjected to a short-pulse laser that can have a temporal span of the order of a nano-, pico-, or a femto-second. Temporal spans having both step and Gaussian distributions are considered. To assess the case of an actual tissue phantom which is an inhomogeneous medium, results have been analyzed by also considering tissue phantom to be a homogeneous medium having the same optical thickness as that of the total optical thickness of the inhomogeneous (real) tissue. Signals for a laser having a temporal span of the order of a nano-second have been found to be more distinct and last longer. With inhomogeneous tissue, for both step and Gaussian temporal profiles, temporal spans of the signals have been found to be more. The analysis has been done using the finite volume method.

Acknowledgments

R. Muthukumaran is currently at the Austrian Institute of Technology, Vienna. He contributed to this work during his stay (May 2008–March 2009) at the Institute of Fluid Science, Tohoku University, Sendai, Japan. SCM contributed to this work during his research stay (August 2008–March 2009) at the Institute of Fluid Science, Tohoku University, Sendai, Japan under an Invitation Fellowship of the Japan Society for Promotion of Science.