Monte-Carlo based Numerical Dosimetry in Reverberation Chamber Exposure Systems Employed for In-Vivo Rodent Bioassays

Authors: De Santis V, Di Fracesco A, Foster KR, Bit-Babik G, Faraone A

Year: 2023

Category: Computational Biology

Journal: IEEE Access

Institution: IEEE

DOI: 10.1109/ACCESS.2023.3251889

URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10057396&isnumber=6514899

Abstract

Overview

A Monte-Carlo based computational approach was applied to study the whole-body specific absorption rate (wbSAR) variability in rodents exposed to radio-frequency (RF) energy. This method illustrated adult male rat exposures as in a US National Toxicology Program cancer bioassay.

Methodology

Generation of numerous 3D electromagnetic field realizations with Rayleigh fading properties within a representative volume of an ideal reverberation chamber.
Analysis of wbSAR distributions in a cohort of 96 homogeneous rodent models with varied mass distribution, postures, positions, and orientations.

Findings

The study covered two exposure scenarios:

Momentary exposure fixed in posture, position, and orientation.
Day-long exposure with varied positions, orientations, and postures.

Results showed lognormal distributions fit the rats’ instantaneous and time-averaged wbSARs. Notably, variability in wbSARs emerged predominantly from Rayleigh field variability (70-80%) and from differences in weight, posture, and position (20-30%).

Conclusion

This research reveals significant insights:

Instantaneous wbSAR variability is extensive, influenced mainly by inherent Rayleigh field properties and less by individual differences among rodents.
Time-averaged wbSARs provide a more focused measure of exposure, important for studies assessing RF-induced thermal effects.
The method’s efficiency supports more nuanced analysis of the interactions between incident electromagnetic fields and biological subjects, which could drive more accurate bioassay standards.

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