Fetd Computation of the Temperature Distribution Induced Into a Human Eye by a Pulsed Laser

Abstract

Abstract-In this paper we present the three-dimensional finite element time domain model of the human eye exposed to pulsed holmium: YAG laser radiation used in thermokeratoplasty procedure. The model is based on the Pennes' bioheat transfer equation and takes into account the focusing action of the lens. The absorption of laser energy inside the eye tissues is modeled using the Lambert-Beer's law. Model takes into account the pulse temporal profile. The maximum temperature values obtained from steady state and transient analysis are compared against those reported from other papers. Finally, sensitivity analysis of several parameters on the calculated temperature field is carried out.

Analysis on the effect of the distances and inclination angles between human head and mobile phone on SAR

“…In this paper, a numerical Anthropomorphic Mannequin (SAM) head model (as shown in Figure 5), which consists of simulating liquids (for shell and brain), is used according to the IEEE standards. The definitions of dielectric materials for human tissues were collected from [16][17][18] to set the appropriate values of relative permittivity and conductivity of materials. Regulation bodies such as IEEE, and IEC have established product compliance standards to assess exposure levels due to mobile phone and have specified the use of SAM phantom in such assessments.…”

Analysis of Materials Effects on Radio Frequency Electromagnetic Fields in Human Head

“…The frequency dependent parameters (the relative permittivity, ε r and conductivity, σ) of the dielectric material was considered, and the values are based on human tissue measurement data, as described in [35][36][37][38][39]. The head model is based on the IEEE Specific Anthropomorphic Mannequin (SAM) model, which consists of a shell and brain simulating liquid.…”

Specific Absorption Rate Computations With a Nodal-Based Finite Element Formulation

“…This quantity is useful to determine, in combination with the heat equation, the temperature increase produced by the incident electromagnetic radiation inside the body, as done in [22]. The SAR is helpful to determine the levels of radiation which are below dangerous limits and can be safely used in therapeutic treatments [23,25,27].…”

“…• The nodal FEM solution of the electromagnetic problem is easier to couple to thermo-mechanical multi-physics problems which usually also employ nodal FEM elements [22].…”