21 0 0 0 OA 電磁界と生体

著者
斎藤 正男 山浦 逸雄
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.12, no.6, pp.341-349, 1974-12-30 (Released:2011-03-09)
参考文献数
99
被引用文献数
2

This paper reviews the effects of electromagnetic fields, from DC to microwaves, on biological systems. Electrical properties of biological substances are briefly described. At DC, strong magnetic fields and steady DC electric fields are reported to produce several effects. At low frequencies, interest of many researchers is centered around stimulation, involuntary movements and shock hazards. produced by currents flowing through the body. Results of several experimental studies are cited. With shifts to higher frequencies, there seem to arise several points which need further clarification. At ultra-high and microwave frequencies, situations are quite different. Most of the effects produced are usually considered attributable to heat developed by electromagnetic energy dissipation, although several papers point out non-thermal effects. Calculations by electromagnetic theory and some experimental results are described. It is emphasized that several points need urgent solution.
著者
清水 優史 龍前 三郎
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.31, no.1, pp.53-60, 1993 (Released:2011-10-14)
参考文献数
18
被引用文献数
1

To simulate blood pressure measurement done by medical doctors, a new type stethoscope, which is a commercialy available stethoscope equipped with an eddy-current displacement sensor and a microphone, is developed. Using this stethoscope and impedance plethysmograph, pulse wave-forms and sounds distal to the cuff and volume change of the artery under the cuff were measured in various experiments. In some experiments, common blood pressure measuring process is adopted and, in other experiments, cuff-pressure is kept constant. From the experimental results, the following facts are known. 1) Blood flow rate coming from upstream in the collapsed artery under the cuff is not affected by arterial pressure distal to the cuff. 2) Always the same sounds are produced when experimental conditions are kept constant. 3) When sounds are heard there exist always steep wave fronts. From these facts, the true mechanism of Korotkoff sound generation is known to be hydrolic-jump formation at the wave front during pressure wave propagation through collapsed artery segment under the cuff.
著者
河村 洋子 横田 康成 亀谷 謙 松村 要
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.39, no.1, pp.56-65, 2001 (Released:2011-10-14)
参考文献数
21

Gender identity disorder (GID) is a condition in which sex differs from gender identity. The basic methodology used to diagnose such a disorder involves examination by more than one psychiatrist. It is necessary to develop objective, quantitative criteria for diagnostics in order to improve the credibility of diagnosis, and to aid in decisions as to whether a patient is eligible for sex reassignment surgery. It has long been believed that there are sex-related differences in the shape and size of the corpus callosum (which interconnects the two cerebral hemispheres), and that these differences could form the basis of an objective, quantitative diagnostic technique. Unfortunately, there are, as yet, no established methods. In this study, we used MRI to investigate sex-related differences in the corpus callosum. We described the callosal figures at the midsagittal plane, using Fourier descriptors and central moments to represent the shape. We found that females have stooping corpus callosum relative to males, at a significance level of 10-14. This suggests that sex-related differences in the corpus callosum may consist of differences in the callosal configurations in the cranium, rather than the shape and size of the corpus callosum. Furthermore, using statistical tests (a likelihood ratio test, Kruskal-Wallis test and Mann-Whitney test), we found that most of the GID subjects in our study (MTF, 4; FTM, 11) have a principal orientation of the corpus callosum that is closer to female than male in sex. This means that the callosal principal orientation may qualify as an objective, quantitative criterion for MTF diagnosis.
著者
戸塚 清 丸田 祐三
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.9, no.2, pp.144-148, 1971-04-30 (Released:2011-03-09)
参考文献数
8

Data communication, referred to as Computer Communication or Remote Data Processing in Western countries, has enabled acquision of numerous data over a wide range and to send back or switch messages to and fro, through linking of the on-line real-time computer data processing and the simultaneity and extensiveness of telecommunications. In the medical fields, three applicable areas for data communication are conceivable as in the general industrial fields.The first area is the centralized storing of medical information for responding to inquiries from remote terminals. The Swedish public health system is an example of this area. It covers the whole population in Sweden under the countrywide network of medical care and keeps the medical records in the personal files of the mass-storage center, based on the central population register.The second is the data communication system to analyse automatically the biomedical signals and raw data from medical examinations. The Medical System Development Laboratory (MSDL), U. S. Public Health Service (USPHS) has been developing the automatic analysis system of the electrocardiograph and the forced expiratory spirogram connecting computers, telephone lines and remote terminals.The third application is the shared data processing system in which the participating users share a computer system and its resources for economical reason. The Minnesota Blue Cross's shared data processing system is an example of this kind.The expected future application of data communication is the remote diagnostic system with the specialist physicians in the center; it will be based on the development of the computer and communication technologies and progress made in technical methods of combining telephone networks with medical instruments.The availability and extensiveness of data communication in the medical fields are herein presented.
著者
山口 昌樹 金森 貴裕 金丸 正史 水野 康文 吉田 博
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.39, no.3, pp.234-239, 2001 (Released:2011-10-14)
参考文献数
15
被引用文献数
17

It is more than a half-century since Dr. Hans Selye proposed that the reaction to an external stimulus to a human be called a “stress.” However, an index that can quantitatively evaluate the stress has not yet been established. We have focused on the change of α-amylase activity in saliva (salivary amylase) and carried out an in vivo evaluation in six normal subjects to define the levels of mental stress through amylase activity. In this evaluation, the Kraepelin Psychodiagnostic Test was used as a mental stressor for the subjects. In normal subjects, a comparatively quick response was observed by the experiment for stress load, which verified a correlation between mental stress and salivary amylase activity. The sign of gradient calculated from the salivary amylase activity was negative or positive, depending on whether the stress reaction is comfortable. Furthermore, when the salivary amylase activity and salivary total protein were measured, the effect of the salivary flow rate could be estimated. The change of salivary amylase activity was confirmed as being originated from stress. These results suggest that the monitoring of salivary amylase could be used as a noninvasive indicator of stress reaction.
著者
長岡 智明 櫻井 清子 国枝 悦夫 渡辺 聡一 本間 寛之 鈴木 保 河川 光正 酒本 勝之 小川 幸次 此川 公紀 久保田 勝巳 金 鳳洙 多氣 昌生 山中 幸雄 渡辺 敏
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.40, no.4, pp.239-246, 2002 (Released:2011-10-14)
参考文献数
16
被引用文献数
11

We have developed high-resolution voxel models of the whole body from MR images of Japanese adult male and female volunteers. These models can be used for dosimetry simulation of exposure to radiofrequency electromagnetic fields over 1GHz. The MR images were taken by making a series of scans over several days; that is, a subject was scanned in several blocks. Scan parameters were optimized for head and body, respectively, in order to get practical contrast and to save data acquisition time. An implement was used to keep the position and form of the subject. All of the MR images were converted to TIFF format. The continuities between different blocks of the data were corrected to form a whole body. Furthermore, the resolution of the images was changed into 2×2mm. Male and female models were segmented into 51 tissues and organs. This segmentation was performed manually using popular image-processing software. The developed models consisted of isotropic voxels with a side of 2mm. Although the masses of the skin and small-sized tissues and organs of the models deviated from the averaged values for Japanese due to the limitation of spatial resolution, the masses of the other tissues and organs and the morphometric measures were nearly equivalent to those of the average Japanese. The models are the first voxel models of the average Japanese that can be used for the dosimetry of electromagnetic fields over 1GHz. Furthermore, the female model is the first of its kind in the world. The models can also be used for various numerical simulations related to Japanese human bodies in other fields of research.
著者
清水 秀明 松本 元
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.13, no.4, pp.207-213, 1975-08-30 (Released:2011-03-09)
参考文献数
12

The light scattering technique with a photoelectron counting method is applied to determine the average swimming velocities or the velocity distribution of spermatozoa. The results are in quantitative agreement with the ones which are obtained in other methods. This technique has proved useful in 'finding the accurate motility of spermatozoa in a very short observation time.
著者
田中 邦雄 佐野 文男 阿部 善右衛門
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.12, no.2, pp.81-89, 1974-04-30 (Released:2011-03-09)
参考文献数
25
被引用文献数
1

Several papers on the applications of the nuclear magnetic resonance (NMR) technique-for the biological measurements have been published since the first proposal of the NMR blood flowmeter by Bowman. However, the problems arising inherently from the non-invasive measurements of the specified area in the body were not discussed in these papers. The authors proposed previously the magnetic focusing technique as one of the new approaches and discussed some problems related to this technique.In this paper, some basic problems of the applications of NMR for the non-invasive measurements are discussed and the fundamental properties affecting the measuring sensitivity attained by the magnetic focusing technique is analyzed. The problems treated and the obtained results are as follows : 1) The relations among parameters such as relaxation times and radio frequency magnetic field which influence the measuring sensitivity are experimentally analyzed.2) The distributions of RF magnetic field inside or outside the transmitter coil are theoretically calculated. Approximate values of relaxation time of 1-2 sec. and 0.1-1 sec. are experimentally obtained respectively with the various body fluids and tissues of the dog and the human. Philosophy of choosing the appropriate parameters are discussed based on these results by taking the saturation factor in Bloch's equation and the measuring sensitivity into account.3) Application for the tumor detection is discussed and the differences of 20% and 200% in relaxation time between normal and cancer cases are experimentally obtained respectively with the tissues from the stomach and the breast. Further, it has been found that the relation between hematocrit of blood and its relaxation time was linear.4) The deterioration of signal output by body tissues is examined by a model experiment. According to this experiment, it is shown that the deterioration of S/N ratio was equal to approximately 30%, at f = 60 MHz.5) From above results, in the case of applying our proposed magnetic focusing technique, the resolution or the minimally detectable volume of water in the typical organs by S/N of unity at resonance frequency of 60 MHz should be about 0.3 ml.
著者
萩 浩司 牧川 方昭 飯泉 仁美
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.4, pp.334-342, 1995 (Released:2011-10-14)
参考文献数
19

In this study we have developed a transcutaneous digital communication technique by using Pulse-Code-Modulated (PCM) infrared rays. The communication protocol examined here is serial, asynchronous and half duplex. The electric power should be considered for a computer system implanted inside the body, because it is driven by batteries and the power is insufficient. Its size should also be miniaturized as small as possible. Therefore the following methods were adopted here; the weak infrared rays emitted inside the body were received by a high sensitive avalanche photodiode; the infrared rays of high brightness was used to send data into inside of the body; and the digital data were converted into an optical signal after the pulse-code-modulation (PCM). This modulation yields some advantages; 1) absorbing the response delay of the photosensor, 2) intensifying infrared rays luminescence outside body and 3) saving the electric power on the luminescence inside body. Some communication experiments were done by using pork with the skin; the communication speed was 9600 baud from inside to outside and 1200 baud in the opposite direction, 15 infrared LEDs were set for outside of the body, 4 for inside, three nickel hydride batteries of 1200mAh were used for an electric power inside the body. As a result, a stable bi-directional digital communication was realized through the skin and the pork of about 9cm and it could continue to operate for about 19 hours.
著者
石山 陽事 白井 康之 野沢 胤美 関 要次郎 本間 伊佐子 江部 充
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.28, no.2, pp.113-121, 1990 (Released:2011-10-14)
参考文献数
12

This study presented the available effects of Source Derivation (SD) method for detecting the focal EEG, from the model experiments which were compared the traditional monopolar derivation with SD method, and also from the clinical recording for the patients, Signal dipole and EEG noise dipole embeded in a spherical volume conducted covered with three layer shells corresponding to neural tissue, skull and scalp, were used for the model. The following conclusions were obtained. 1) It was proved by the model experiment that SD method was useful for the detection of focal signal dipole potential on cortical surface. 2) SD method was useful to detect the signal not only in the cortical surface but also in the deep cortical area, when the reference electrode angle of SD method was smaller to the active electrode (α=10°-20°), that is, the distance of electrodes on scalp surface was about 1.6-3.2cm. 3) SD method was applied to the patients with focal spikes. The localization of the focal spike was more clear than the traditional ear reference monopolar recording. S/N to back ground EEG also was improved very well. 4) Identification of the location generated of primary responses in somatosensory evoked potential (SEP) by electrical stimulation of median nerve was tried by using the SD method with intererectrode distance of 2cm, and consequently the central sulcus and cortical primary sensory area were identified from the phase-reversal of SEP on the scalp.