ID Number		1547
Study Type		Engineering & Physics
Model		Computational Dosimetry in Animals (catch-all)
Details		Computational Dosimetry in Animals (catch-all) AUTHORS' ABSTRACT: Jingjing et al. 2014 (IEEE #5785): This paper aims to achieve a high-quality exposure level quantification of whole-body average-specific absorption rates (WBA-SARs) for small animals in a medium-size reverberation chamber (RC). A two-step method, which incorporates the finite-difference time-domain (FDTD) numerical solutions with electric field measurements in an RC-type exposure system, has been used as an evaluation method to determine the whole-body exposure level in small animals. However, there is little data that quantitatively demonstrate the validity and accuracy of this method in an RC up to now. In order to clarify the validity of the two-step method, we compare the physical quantities in terms of electric field strength and WBA-SARs by using a direct numerical assessment method known as the method of moments (MoM) with ten homogenous gel phantoms placed in an RC with 2GHz exposure. The comparison results show that the relative errors between the two-step method and the MoM approach are approximately below 10%, which reveals the validity and usefulness of the two-step technique. Finally, we perform a dosimetric analysis of the WBA-SARs for anatomical mouse models with the two-step method and determine the input power related to our developed RC-exposure system to achieve a target exposure level in small animals. AUTHORS' ABSTRACT: Chakarothai et al 2015 (IEEE #6045): Reverberation chamber (RC) has been recently developed and used in bio-electromagnetic (EM) field research for investigation of possible adverse health effect of EM waves to human body. Concerning the use of an RC as an exposure device, accurate dosimetry or quantification of EM energy absorbed in exposed animals inside an RC is actually of importance. However, the dosimetry of animals inside an RC is one of challenging problems due to its size and complex behavior of EM fields inside the chamber. This paper is dedicated to the demonstration of three different numerical techniques developed for dosimetry of small animals exposed to EM fields inside an RC at microwave frequencies. First we briefly review procedures of each numerical method and clarify its advantages, disadvantages, and range of applications. Then we demonstrated their validity by either experiments or cross-verification. Finally we discuss the results obtained from each numerical technique. AUTHORS' ABSTRACT: Papaioannou and Samaras 2011 (IEEE #6050): A numerical model of the anterior chamber of the rabbit eye is presented. The model takes into account both the fluid dynamics of the aqueous humor and the realistic boundary conditions at the interface of the cornea with the environment. The model is used to determine the temperature distribution and velocity field under 60-GHz millimeter wave radiation. The maximum predicted temperature (45.8°C for an incident power density of 475 mW/cm2) is in good agreement with experimental results. Moreover, the model shows that there is a value for the incident power density (about 100 mW/cm2) for which the direction of aqueous humor flow due to buoyancy is inverted, because of the inversion of the temperature gradient in the anterior chamber of the eye. This phenomenon has already been reported from experimental observations and can be numerically studied, if aqueous humor fluid dynamics are taken into account in the heat-transfer model. AUTHORS' ABSTRACT: Chen et al. 2017 (IEEE #6744): As electromagnetic exposure experiments can only be performed on small animals, usually rats, research on the characteristics of specific absorption rate (SAR) distribution in the rat has received increasing interest. A series of calculations, which simulated the SAR in a male rat anatomical model exposed to electromagnetic plane waves ranging from 0.05 to 5 GHz with different incidence and polarization, were conducted. The whole-body-averaged SAR (SARwb) and the tissue-averaged SAR (SARavg) in 20 major tissues were determined. Results revealed that incidence has great impact on SAR in the rat at higher frequencies owing to the skin effect and the effect on SARavg in tissues is much more apparent than that on SARwb; while polarization plays an important role under lower frequencies. Not only the incidence, but also the polarization in the rat keeps changing when the rat is in free movement. Thus, this article discussed a convenient way to obtain relatively accurate SARwb in a free-moving rat.
Findings		Ongoing
Status		Completed With Publication
Principal Investigator
Funding Agency		?????
Country		UNITED STATES
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