Multiphysics and Thermal Response Models to Improve Accuracy of Local Temperature Estimation in Rat Cortex under Microwave Exposure
Abstract
:1. Introduction
2. Materials and Methods
2.1. Animal Experiments
2.1.1. Animals
2.1.2. Definition of the Target Area
2.1.3. Measurement of Physiological Parameters
2.1.4. The 1.5 GHz Experimental System
2.1.5. The 6 GHz and 10 GHz Experimental Systems
2.2. Numerical Rat Model and Exposure Scenarios
2.3. SAR Computation
2.4. Temperature Computation
2.4.1. Bioheat Equation
2.4.2. Blood Flow
2.4.3. Thermal Constants
2.4.4. Evaluation Index for Effects of Thermoregulation
2.4.5. Data Analysis
3. Results
3.1. Time-Course of Changes in Physiological Parameters
3.2. Temperature Conditions in Animal Experiments
3.3. Extraction of Parameters Associated with the Blood Flow Rate in the Brain
3.4. Effects of Thermoregulation
3.5. Computation of the SAR and Temperature Distributions in the Numerical Rat Model
3.6. Comparison of Temperature Elevations Between Live Rats and Numerical Rat Models
4. Discussion
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Tissues | 1.5 GHz | 6 GHz | 10 GHz | |||
---|---|---|---|---|---|---|
εr | σ | εr | σ | εr | σ | |
(S·m−1) | (S·m−1) | (S·m−1) | ||||
Fat | 11.1 | 0.16 | 9.8 | 0.87 | 8.8 | 1.71 |
Muscle | 54.9 | 1.38 | 48.2 | 5.20 | 42.8 | 10.63 |
Bone | 23.8 | 0.65 | 15.2 | 2.23 | 12.7 | 3.86 |
Eye | 68.7 | 1.89 | 47.5 | 5.72 | 41.5 | 11.31 |
Brain | 46.7 | 1.15 | 43.7 | 5.22 | 38.1 | 10.31 |
Skin | 39.4 | 1.07 | 34.9 | 3.89 | 31.3 | 8.01 |
Tissues | ρ | K | C | B0 | A |
---|---|---|---|---|---|
(kg·m−3) | (W·m−1·°C−1) | (J·kg·°C−1) | (W·m–3·°C−1) | (W·m−3) | |
Fat | 916 | 0.25 | 3000 | 6299 | 4983 |
Muscle | 1047 | 0.50 | 3800 | 2880 | 2278 |
Bone | 1990 | 0.37 | 3100 | 12,317 | 9743 |
Eye | 1009 | 0.57 | 4000 | 0 | 0 |
Brain | 1038 | 0.57 | 3800 | 35,692 | 28,233 |
Skin | 1125 | 0.42 | 3600 | 11,605 | 9180 |
f | BASAR | I_ΔTW/O | I_ΔTW | Reduction |
---|---|---|---|---|
(GHz) | (W·kg−1) | (%) | (%) | (percentage Point) |
1.5 | 75 | 6.6 | 2.7 | 3.9 |
6 | 64 | 9.2 | 3.7 | 5.5 |
106 | 19.3 | 4.7 | 14.6 | |
10 | 29 | 10.7 | 7.2 | 3.5 |
79 | 18.7 | 5.3 | 13.4 |
f (GHz) | BASAR (W·kg−1) | Target Temperature (°C) | Rectal Temperature (°C) | ||
---|---|---|---|---|---|
Before | After | Before | After | ||
1.5 | 0 | 33.3 ± 0.1 | 33.5 ± 0.1 | 37.1 ± 0.1 | 37.2 ± 0.1 |
75 | 33.0 ± 0.2 | 36.2 ± 0.2 * | 37.4 ± 0.1 | 37.9 ± 0.0 * | |
6 | 0 | 30.3 ± 0.3 | 31.1 ± 0.2 | 37.5 ± 0.2 | 37.6 ± 0.3 |
64 | 30.9 ± 0.6 | 35.6 ± 0.6 * | 37.0 ± 0.2 | 37.6 ± 0.2 | |
106 | 30.6 ± 0.1 | 37.6 ± 0.2 * | 37.3 ± 0.2 | 38.2 ± 0.1 * | |
10 | 0 | 30.2 ± 0.6 | 30.4 ± 0.2 | 36.7 ± 0.2 | 36.7 ± 0.2 |
29 | 30.1 ± 0.3 | 33.6 ± 0.4 * | 36.4 ± 0.2 | 36.5 ± 0.1 | |
79 | 29.4 ± 0.3 | 36.5 ± 0.2 * | 36.5 ± 0.1 | 36.7 ± 0.0 |
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Kodera, S.; Gomez-Tames, J.; Hirata, A.; Masuda, H.; Arima, T.; Watanabe, S. Multiphysics and Thermal Response Models to Improve Accuracy of Local Temperature Estimation in Rat Cortex under Microwave Exposure. Int. J. Environ. Res. Public Health 2017, 14, 358. https://doi.org/10.3390/ijerph14040358
Kodera S, Gomez-Tames J, Hirata A, Masuda H, Arima T, Watanabe S. Multiphysics and Thermal Response Models to Improve Accuracy of Local Temperature Estimation in Rat Cortex under Microwave Exposure. International Journal of Environmental Research and Public Health. 2017; 14(4):358. https://doi.org/10.3390/ijerph14040358
Chicago/Turabian StyleKodera, Sachiko, Jose Gomez-Tames, Akimasa Hirata, Hiroshi Masuda, Takuji Arima, and Soichi Watanabe. 2017. "Multiphysics and Thermal Response Models to Improve Accuracy of Local Temperature Estimation in Rat Cortex under Microwave Exposure" International Journal of Environmental Research and Public Health 14, no. 4: 358. https://doi.org/10.3390/ijerph14040358