著者

藤井 麻美子 戸田 康永 根岸 聡 酒本 勝之 金井 寛

出版者

Japanese Society for Thermal Medicine

雑誌

日本ハイパーサーミア学会誌 (ISSN:09112529)

巻号頁・発行日

vol.13, no.1, pp.18-27, 1997-03-01 (Released:2010-01-28)

参考文献数

3

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超音波ハイパーサーミアの大きな問題点として, 音響インピーダンスの著しく異なる境界面 (肺や骨など) での発熱があげられる.この発熱は患者に激痛を与え, その結果, 目的部位を十分に加温できなくなる.そして多くの場合, 治療を中断せざるを得なくなる.そこで本研究ではこの問題を筋肉-骨境界面に限定し, その発熱の原因を数値計算とモデル実験により解析した.超音波の伝搬において, 境界面における反射・透過率, さらには伝搬の圧縮波からずり波へのモード変換などは超音波の入射角度に大きく依存するので, 特に温度分布の角度依存性に注目して検討を進めた.

著者

酒本 勝之 金子 和真 江崎 光裕 藤井 麻美子 金井 寛 浅野 次義

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.33, no.3, pp.184-191, 1995 (Released:2011-10-14)

参考文献数

14

被引用文献数

2

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A new method (BIM) by bioelectrical impedance for the estimation of human whole body or local part fat volume is described. This method is based upon that the resistivity of adipose tissue is much greater than that of fat-free mass of which frequency characteristics shows β dispersion phenomenon. It is well known that the admittance locus of fat-free mass provides the semicircle. Because the impedance value of trunk is only 10 or 20% of the whole body impedance (Zall) between arm and leg used by the commercialized impedance fat meter, if the fat volume in the trunk increase, the estimation error in the fat volume estimated from Zall would increase. Therefore, instead of Zall, BIM adopts the impedances measured at 5 local parts which are antebrachium, brachium, trunk, femoral part and cruralis. We measured the impedance of each parts for the frequency range from 3kHz to 300kHz and calculate the admittance locus in order to obtain the conductance at much lower frequency (Ge) and much higher frequency (Ginf) than β dispersion frequency. Arms, trunk and legs are represented by parallel models which are cone shape and consists of fat layer and fat-free mass layer. And then we calculate the equivalent conductivity σ of parallel models from Ge or Ginf. From σ, fat volumes of local parts which are arm, trunk and leg and whole body are estimated. When we estimate the fat volume of trunk, in order to take into consideration the adipose tissue which distributes around organs in trunk like liver, stomach, and etc., the weighting function K which is statistically given is multiplied to the equivalent conductivity of trunk. The reference fat volume can be measured by hydrometry. We can conclude that (1) the impedance at the trunk must be measured to consider the fat volume in the trunk, (2) Ge or Ginf must be used instead of impedance at about 50kHz to estimate the fat volume, and (3) correlation coefficients between the whole fat volume measured by hydrometry and that by BIM with Ge and Ginf are about 0.77 and 0.94, respectively.

著者

晴山 典彦 藤井 麻美子 酒本 勝之 金井 寛

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.34, no.3, pp.230-237, 1996 (Released:2011-10-14)

参考文献数

6

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It is very difficult to heat deep seated tumor surrounded by low conductivity tissues, such as bone and fat. We proposed a new RF magnetically induced method for this deep regional hyperthermia. To get high density of induced current in deep tissues, we arranged 4 coils around the sphere agar phantom. The frequency of exciting current is 13.56MHz. In this paper, we will show the calculation method of SAR distribution and temperature distribution in 3D inhomogeneous model. We also discuss the possibility of this heating method from both experiment and calculated results. In the phantom experiment we examined two types of the coils. The calculated results and experimental results show a good agreement, these therefore, the reliability of this calculation method was confirmed. The heating pattern of these coils were not very effective for deep regional hyperthermia. We also calculated temperature distribution in the brain model which was constructed from CT images. We assumed tumor in the brain with half of the blood flow compare to normal tissue. Deep seated tumor was heated by the effect of inhomogeneity and blood flow, except there were hot spots near the coil. In the case of shallow region heating, we can get effective localized heating pattern. From these results, we cannot surely say that this heating method is quite sufficient for deep regional hyperthermia. But since there is no other method to successfully heat the brain non-invasively, this kind of examination with other coil patterns must be continued.

著者

福田 恵子 藤井 麻美子 深谷 直樹

出版者

東京都立産業技術高等専門学校

雑誌

基盤研究(C)

巻号頁・発行日

2011

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近赤外分光法による脳機能計測において、測定信号に含まれる姿勢変化等の外乱や感情等の情報を含む皮膚血流の影響を大脳皮質血流から分離する計測法に関する研究を行った。まず、提案する2種類の補正信号を用いる皮膚血流変化の影響の補正手段に関して、シミュレーション及びファントム実験により、有効性を確認した。また、手段の実現に適した信号の変調・復調方式を提案し、その動作をファントム実験にて確認した。また、生体計測においては、皮膚血流の補正信号を測定対象信号と同時に計測し、測定対象信号に含まれる外乱の影響を確認した。