Evaluation of whole-body averaged SAR and temperature elevation for far-field exposures

• Project/Area Number: 18360136
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 電力工学・電気機器工学
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: FUJIWARA Osamu Nagoya Institute of Technology, 大学院・工学研究科, 教授 (60135316)
• Co-Investigator(Kenkyū-buntansha): HIRATA Akimasa 名古屋工業大学, 工学研究科, 准教授 (00335374) ; SHIOZAWA Toshiyuki 中部大学, 工学部, 教授 (40029210) ; KAMIMURA Yoshitsugu 宇都宮大学, 工学研究科, 准教授 (20233950)
• Project Period (FY): 2006 – 2008
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥16,280,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥2,580,000); Fiscal Year 2008: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000); Fiscal Year 2007: ¥7,800,000 (Direct Cost: ¥6,000,000、Indirect Cost: ¥1,800,000); Fiscal Year 2006: ¥5,100,000 (Direct Cost: ¥5,100,000)
• Keywords: 電気・電磁環境 / 遠方界 / 比吸収率 / 温度上昇 / 電波防護指針 / マイクロ波

Research Abstract

本研究では、遠方より詳細な人体モデルに電波を照射した際に、モデル内に吸収される電力および伴う体内深部の温度上昇を解析することにある。まず、日本人を対象として構築された詳細なモデルに対する全身平均SARの大規模解析を実施した。特に、全身平均SARは、国際非電離放射線防護委員会の定めたガイドラインに対して、自由空間においては身長が約0.4波長に相当する周波数および2GHz付近で極大となることを明らかにした。また、生体熱輸送方程式に改良を加え、体内深部温度上昇の解析が行えるような定式化を構築した。
特に、全身平均SARと体内温度上昇の相関にっいて考察を行い、全身平均SARが一定であれば、温度上昇は周波数にほとんど依存しないことを明らかにした。但し、性別およびモデル体形などにより影響を受けることもわかり、その評価が今後の検討課題となる。

Research Products

• [Journal Article] Influence of electromagnetic polarization on whole-body averaged SAR in children for plane-wave exposures (2009)
  • Author(s): A. Hirata, N. Ito, and O. Fujiwara
  • Journal Title: Physics in Medicine and Biology
• [Journal Article] nfluence of electromagnetic polarization on whole-body averaged SAR in children for plane-wave exposures (2009)
  • Author(s): A. Hirata, N. Ito, O. Fujiwara
  • Journal Title: Physics in Medicine and Biology 53
  • Peer Reviewed
• [Journal Article] FDTD analysis of body-core temperature elevation in children and adults for whole-body exposure (2008)
  • Author(s): A. Hirata, T. Asano, and O. Fujiwara
  • Journal Title: Phys. Med. Biol vol.53 Pages: 5223-5238
• [Journal Article] FDTD analysis of body-core temperature elevation in children and adults for whole-body exposure (2008)
  • Author(s): A. Hirata, T. Asano, O. Fujiwara
  • Journal Title: Physics in Medicine and Biology 53 Pages: 5223-5238
  • Peer Reviewed
• [Journal Article] Conservative estimation of whole-body-averaged SARs in infants with a homogeneous and simple-shaped phantom in the GHz region (2008)
  • Author(s): A. Hirata, N. Ito, 0. Fujiwara, T. Nagaoka, S. Watanabe
  • Journal Title: Physics in Medicine and Biology 53 Pages: 7215-7223
  • Peer Reviewed
• [Journal Article] 人体の吸収断面積と体表面積の相関性に基づくGHz帯全身平均SARの予測式と不確定性 (2008)
  • Author(s): 長屋 義男, 平田 晃正, 藤原 修、 長岡 智明, 渡辺 聡一
  • Journal Title: 電子情報通信学会論文誌(B) 90-B
  • NAID: 110007379120
  • Peer Reviewed
• [Journal Article] Dominant factors influencing whole-body average SAR due to far-field exposure in whole-body resonance frequency and GHz regions (2007)
  • Author(s): A. Hirata, S. Kodera, J. Wang, and O. Fujiwara
  • Journal Title: Bioelectromagnetics vol.28 Pages: 484-487
• [Journal Article] FDTD analysis of human body-core temperature elevation due to RF far-field energy prescribedi n ICNIRP guidelines (2007)
  • Author(s): A.Hirata, T.Asano, O.Fujiwara
  • Journal Title: Physics in Medicinea nd Biology 52 Pages: 5013-5023
  • Peer Reviewed
• [Journal Article] factors for influencing whole-body average SAR due to far-field exposure in whole-body resonance frequency and GHz regions (2007)
  • Author(s): A.Hirata, S.Kodera, J.Wang, O.Fujiwara
  • Journal Title: Bioelectromagnetics (In press)
• [Presentation] FDTD computation of temperature elevation in human body for RF far-field exposure (2008)
  • Author(s): A. Hirata, T. Asano, 0. Fujiwara
  • Organizer: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
  • Place of Presentation: カナダ・バンクーバー
  • Year and Date: 2008-08-20
• [Presentation] Formula for estimating whole-body average SAR in human models due to plane-wave exposure at resonance frequency (2008)
  • Author(s): A. Hirata, Y. Hiraiwa, O. Fujiwara, T. Nagaoka, S. Watanabe
  • Organizer: 信学技報
  • Place of Presentation: 北海道大学(EMC-08-18)
• [Presentation] FDTD computation of temperature elevation in human body for RF far-field exposure (2007)
  • Author(s): A.Hirata, T.Asano, O.Fujiwara
  • Organizer: Annual International Conference of the IEEE Engineering in Medicine and Biology
  • Place of Presentation: フランス・リヨン
  • Year and Date: 2007-08-23
• [Presentation] Correlation between absorption cross section and body surface area ofhuman for far-field exposure at GHz bands (2007)
  • Author(s): A.Hirata, Y.Nagaya, O.Fujiwara, T.Nagaoka, and S.Watanabe
  • Organizer: IEEE International Symposium on Electromagnetic Compatibility
  • Place of Presentation: アメリカ・ハワイ
  • Year and Date: 2007-07-11
• [Presentation] A formula for predicting whole-body average SAR in human models for far-field exposure at GHz bands (2007)
  • Author(s): A.Hirata, Y.Nagaya, O.Fujiwara, T.Nagaoka, and S.Watanabe
  • Organizer: Bioelectromagnetics 2007
  • Place of Presentation: 金沢
  • Year and Date: 2007-06-11
• [Presentation] Correlation between absorption cross section and body surface area of human for far-field exposure at GHz bands (2007)
  • Author(s): A. Hirata, Y. Nagaya, O. Fujiwara, T. Nagaoka, S. Watanabe
  • Organizer: IEEE International Symposium on E Iectromagnetic Compatibility
  • Place of Presentation: (TU-PM-41)
• [Presentation] Temperature elevation in the eye of Japanese male and female models for plane wave exposures (2006)
  • Author(s): A. Hirata, S. Watanabe, O. Fujiwara, M. Kojima, K. Sasaki, T. Shiozawa
  • Organizer: 電気学会電磁環境研究会
  • Place of Presentation: NICT(EMC-06-17)
• [Presentation] Mechanism for double-humped frequency characteristics of whole-body average SAR due to far-field exposure at ICNIRP reference level (2006)
  • Author(s): A. Hirata, S. Kodera, J. Wang, and O. Fujiwara
  • Organizer: EMC Europe
  • Place of Presentation: Barcelona, Spain(598-602)