Abstract
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.
