著者

阿部 善右衛門 田中 邦雄 堀田 正生

出版者

公益社団法人 計測自動制御学会

雑誌

計測自動制御学会論文集 (ISSN:04534654)

巻号頁・発行日

vol.10, no.3, pp.290-297, 1974-06-30 (Released:2009-03-27)

参考文献数

29

被引用文献数

1

---

The possibilities for the measurements of the blood flow and water contents in the human body by NMR techniques have been analyzed during the last four years. A new technique for this purpose is proposed as one of the new approaches.This paper will deal with the following four topics connected with our past studies for noninvasive testing of biological materials.(1) Proposal of magnetic focusing techniques and generation of the focusing field.(2) Deterioration of the signal level originating frcm the loose coupling between the measuring target and the detector, and minimum limit for measurements of the stationary body fluid utilizing steady NMR.(3) Improvement on the blood flowmeter utilizing pulse NMR.(4) Measurement of the stationary body fluid utilizing pulse NMR.For non-invasive measurements of the nuclear magnetic substances distributed in the human body, a new approach is proposed by utilizing the magnetic focusing technique on the measuring target. And several methods for generating this magnetic focus are discussed theoretically. Moreover, the degree of inevitable deterioration of the signal from the focus induced by a loose coupling between the target in the body and the detector on its surface is calculated theoretically.Theoretical estimations of a new blood flowmeter are shown by taking advantages of the tag effect by radio frequency pulse on the blood flow.For this improvement of the blood flowmeter, the techniques are explained to estimate the pseudo-signal intensity originating from the neighbouring tissues around the blood vessel. A method similar to blood flowmetry can also be applicable to detect the stationary body fluids with some modifications.And some simple assumptions of the minimum limit of detectability are summarized from the view point of bio-medical applications.In conclusion, the authors are able to explain a few considerations and theoretical prospects on these applications of NMR.

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

小林 隆 堀口 貞夫 藤井 仁 武井 徳郎 河本 久 天野 和彦 井上 毅 穂垣 正暢 松本 ゆり子 阿部 善右衛門 鈴木 孝治

出版者

日本産科婦人科学会

雑誌

日本産科婦人科學會雜誌

巻号頁・発行日

vol.16, no.8, pp.778-780, 1964

著者

山本 悦治 山田 芳文 阿部 善右衛門

出版者

北海道大学応用電気研究所

雑誌

応用電気研究所報告 (ISSN:00307726)

巻号頁・発行日

vol.29, no.4, pp.p213-234, 1977-12

著者

阿部 善右衛門 山田 芳文

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.17, no.7, pp.530-537, 1979-12-30 (Released:2011-03-09)

参考文献数

37

著者

山本 悦治 山田 芳文 阿部 善右衛門

出版者

公益社団法人 計測自動制御学会

雑誌

計測自動制御学会論文集 (ISSN:04534654)

巻号頁・発行日

vol.14, no.2, pp.163-170, 1978-04-30 (Released:2009-03-27)

参考文献数

14

---

Previously we proposed a new application of NMR to measure biological materials in human body noninvasively, using the magnetic focusing technique on the measuring target (MT).The present paper considers how to generate the magnetic focus and demonstrates this technique by using the low-field NMR spectrometer.In the first parts of this paper, the signal error due to the fringe region of MT is evaluated theoretically and the constant field contours for several arrangements of multiple coils are calculated so as to generate the magnetic focus.Simple results are obtained analytically for the axisymmetric field especially. Furthermore, a new approach which enlarges the zero-flux region is proposed to achieve a high S/N ratio.In the latter parts, the construction of 100kHz NMR spectrometer, whose static field H0 is generated by the main solenoid 70cm long and 40cm in diameter with two compensation windings, is described. The proton resonance signals from 1cm3 sample water are obtained with a S/N ratio of 15, which is more than ten times better than the value estimated from the relation S/N∝H02/3.By using the separate samples under the gradient field, a separate signal corresponding quantitatively to each sample is obtained. The signal from a certain specified area near the surface of a large sample has a shifted resonant frequency and an emphasized magnitude when the magnetic focusing technique is applied.

著者

田中 邦雄 清水 哲也 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.14, no.1, pp.25-32, 1976-02-29 (Released:2011-03-09)

参考文献数

19

---

Since R. Damadian suggested the detectability of tumors by nuclear magnetic resonance (NMR), the authors have focused their attention on the facts such as the quantities related to the kinds of water and tissues. And at least qualitative information could be non-invasively obtained.In this paper, in order to clarify the applicabilities of our proposed magnetic focusing method for non-invasive tumor detection, the nuclear magnetic relaxation time (T1) of transplanted malignant tumor (AH-66) in rat, excised normal and cancerous tissues in man were measured in vitro experiment.The resultant findings are summarized as followings.1) Transplanted malignant tumor in rat showed (30-120) % longer value of T1 than that of the respective normal tissues.2) In 14 cases of the uterus, breast and stomach in man, the T1 of cancerous tissues increased (10-150) % than that of their normal portions.3) When mixed tissue was studied, T1 changed as the ratio of tumor to normal tissue changed.4) The longer the time elapsed, the greater the T1 value exhibited by normal and the smaller the T1 measured for cancerous tissue. When both normal and cancerous tissues coexist, T1 decrement of the tissue is small.

著者

阿部 善右衛門 和田 龍彦

出版者

公益社団法人 計測自動制御学会

雑誌

計測と制御 (ISSN:04534662)

巻号頁・発行日

vol.17, no.9, pp.690-696, 1978 (Released:2009-11-26)

参考文献数

35