| Presentation | 2011-05-26 Electric Field Induced in Retina and Brain at Threshold Magnetic Flux Density Causing Magnetophosphenes Akimasa Hirata, Yukinori Takano, Osamu Fujiwara, |
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| Abstract(in Japanese) | (See Japanese page) | |||
| Abstract(in English) | In the international safety guidelines/standards, the rationale for human protection from extremely-low-frequency magnetic field exposure is to prevent the magneto-stimulation. The threshold in-situ electric field for magnetophosphenes has been experimentally derived as 8.14 mT at 20 Hz. However, the corresponding in-situ electric field in the central nervous system has not been well investigated. The present study derived computationally in-situ electric field in the brain and retina in different anatomically-based numeric human models exposed to uniform magnetic fields at extremely low frequencies. A quasi-static finite-difference time-domain method was applied to analyze this problem. First, the computational uncertainty caused by using a stair-casing model is investigated by comparing the electric field induced in a three-layer sphere obtained by the computational method to an analytical solution. In addition, the electric fields induced in anatomically-based models with different resolutions are also compared. For our computational results, the 99^ | percentile value of the in-situ electric field is found to be reasonable both for the sphere and anatomically-based models with different resolutions. Then, the 99^ | percentile values of the electric field in the brain and retina in different models are computed for exposure at the threshold magnetic flux density for magnetophosphenes. When comparing the 99^ | percentile value in the brain of the anatomically-based model with those derived from an ellipsoid defined in the IEEE standard, the former was 10-70% larger than the latter. The main reason for this difference is attributed to the remaining part of the body in addition to the model inhomogeneity. |
| Keyword(in Japanese) | (See Japanese page) | |||
| Keyword(in English) | computational dosimetry / in-situ electric field / magnetophosphenes | |||
| Paper # | EMCJ2011-19,MW2011-16,EST2011-12 | |||
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| Committee | EMCJ |
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| Conference Date | 2011/5/19(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Topics (in Japanese) | (See Japanese page) |
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| Registration To | Electromagnetic Compatibility (EMCJ) |
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| Language | ENG |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Electric Field Induced in Retina and Brain at Threshold Magnetic Flux Density Causing Magnetophosphenes |
| Sub Title (in English) | |
| Keyword(1) | computational dosimetry |
| Keyword(2) | in-situ electric field |
| Keyword(3) | magnetophosphenes |
| 1st Author's Name | Akimasa Hirata |
| 1st Author's Affiliation | Graduate School of Engineering, Nagoya Institute of Technology() |
| 2nd Author's Name | Yukinori Takano |
| 2nd Author's Affiliation | Graduate School of Engineering, Nagoya Institute of Technology |
| 3rd Author's Name | Osamu Fujiwara |
| 3rd Author's Affiliation | Graduate School of Engineering, Nagoya Institute of Technology |
| Date | 2011-05-26 |
| Paper # | EMCJ2011-19,MW2011-16,EST2011-12 |
| Volume (vol) | vol.111 |
| Number (no) | 64 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |