Databases have recently been produced and are utilized by means of large computer for information processing in the medical field. However, it is difficult for medical doctors or medical technicians, who are not specialists in information processing, to master this computer and software system. Therefore, an attempt has been made to produce a database system which can easily be used without knowledge of databases and which is inexpensive and has wide use. The dBASE II, which is widely used for personal computers, has been utilized as the basic software for our system. The characteristics of our program are as follows: 1) the functions of dBASE II software are within our system; 2) the entire processing is of dialogue type; 3) it has a function of statistical processing by which lack of data can be indicated and excepted on analysis and which is considered to be necessary in the medical field. It is concluded that our system is very useful as a database system for individuals or in various fields of medicine.

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To obtain a high reliability of fibrillation detection in an implantable automatic defibrillator, a new fibrillation sensor has been developed, and also the defibrillator circuit has been improved.
For reliable fibrillation sensing, dual criteria before delivering a shock has been required. Therefore, for the first purpose, a new fibrillation sensing method feasible to simultaneous use with existing ECG sensing, was considered. In our research, blood pressure variation was used as another fibrillation detection factor, and a loss of rhythmic output of the sensor was used to detect fibrillation condition. To be more specific, to detect blood pressure variations intravenously, a catheter type variable capacitance pressure sensor of low power consumption was developed. As the sensing unit, an electret condenser microphone (Matsushita Electric Co. Ltd.: WM 063) was used. The outside was covered with an adhesive (Ciba Geigy Co. Ltd.: Araldite) and polyurethane (Nippon polyurethane Co. Ltd.: P-22 S) for waterproofing and providing antithrombogenesity.
For the second purpose, the output circuit of the defibrillator was improved. A gate turn-off thyristor (Hitachi Co. Ltd.: GFT 20 B) was used as an output switching device for consuming energy effectively.
The developed sensor and defibrillator were tested in animal experiments. The blood pressure sensor was able to detect the right ventricular pressure variations for 6 weeks at maximum in chronic experiments using 4 mongrel dogs. In acute experiments, the sensor detected electrically induced fibrillation, and defibrillating shock was delivered automatically. Moreover, recharge time after the first stimulation was about 25% shorter because of the residual energy remaining in the capacitor by the improved output circuit.
From the results, it has become possible to detect fibrillation reliably using blood pressure sensor as well as ECG. Therefore, by combining the blood pressure sensor and ECG sensing for accurate fibrillation sensing, and by improving the output circuit, development of a high-performance defibrillator has become possible.

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A weak magnetic field associated with eye movement (Magneto-oculogram: MOG) is analysed both experimentally and theoretically in this study.
First, a spatial distribution of the MOG signals is experimentally measured by SQUID (Superconducting Quantum Interference Device) with a second derivative gradiometer in a magnetically shielded room.
Second, under the assumption that the source of the MOG signals can be approximated by one current dipole, it has been theoretically conjectured that there exists a current dipole of 200-350nA-m in the retina.

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A measurement of the force bearing down on the foot skeletal system through the foot sole is effective for the diagnosis of various foot disorders or the evaluation of the treatment. From this point of view a portable computerized gait analysis system has been developed here to record and analyze the dynamic under-foot force distribution in more daily-life-like situations. In this study some normal subject's dynamic under-foot force distribution in various modes of walking has been studied as the first step towards clinical application of this system.
This system is a kind of small battery-driven computer system (15×9×3cm, 700g) and is constructed of the minimum number of elements. It comprises the CPU (Z80), memory (64Kbyte), A/D converter, etc., necessary to measure various kinds of biological signal. The force distribution sensor used here is an ultra-thin pressure-strain guage (1.5mm in thickness and 8mm in diameter); eight sensors are fixed by adhesive tape on eight points on the foot sole, including the heel, the outside of the midfoot, five metatarsal heads and the great toe.
In the experiment the force distribution under the foot is measured in various modes of walking, that is, a voluntary speed walking, jogging, going up or down the stairs, etc. Results show that the force distribution diversely changes in each subject or mode of walking, but some new findings about the foot function could be acquired from these results. Moreover a method by using this system to analogize the force bearing down on the foot in daily life is proposed here.

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Dual energy technique, which utilizes non-linear characteristics of X-ray attenuation coefficients, can provide images which display specific substances distinguished by the differences of attenuation coefficients. In this paper, basic phantom study has been performed using slit-scanography to develop an experimental procedure to separate acryl and iodine parts from X-ray images taken by two different X-ray tube voltages. Since misalignment of two images causes a number of artifacts, which degrade the image quality severely, a correction procedure has been developed to suppress this kind of artifacts. Several energy filters made of some rare metals have also been tested to make large energy spectral differences between two tube voltages. This method has been applied to make soft tissue image and bone structure image from slit-scanographic images for several clinical cases. This technique has also been applied to the digitized X-ray film images. In the results for several clinical cases, it is shown that the contrast of soft tissue is emphasized and the contrast of bone structure is suppressed in the soft tissue images, which help us observe the focuses with low contrast or surrounded by bones. In the case of osteosarcoma, the contrast of focus has been emphasized in bone image though it is suppressed in soft tissue image. Several resulting images in the paper indicate the efficiency of this technique in clinical fields.

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Measuring principle of the single axis flexible electrogoniometer using conductive rubber and the result of manufacturing by way of trial are described. Four thin beams made of electro conductive rubber are plastered on the two opposite sides of elastic rubber column with uniform cross section, to form a wheatstone bridge circuit. The total amount of elongation of each conductive rubber beam changes in proportion to the angle between both ends of the beam and does not depend on the deformation curves of the beam. Though the relation between the quantity of elongation and electro resistance of conductive rubber is nonlinear and shows hysteresis loop, the difference of electro resistance of the conductive rubber between tensile and compressive sides on the elastic column changes linearly and has less hysteresis loop, with suitable choice among various kind of electro conductive rubber materials. As a result, output voltage of the bridge circuit shifts approximately linearly with the angle between both ends of the column.
This electrogoniometer is very easy to flex and thin (under 10mm thickness), has no convex part to the side direction, and can be used without taking off clothes. Moreover, it is easy to be attached on the joint without considering about alignment and is useful for measuring various kinds of human joints from large hip joint to small finger joint, and even of artificial limb joints.
Trial manufacture for human knee joint has been undertaken and compared with the values calculated from simultaneously measured movie camera data. The difference between the two proved under 5%. The nonlinearity is under 2.3% and hysteresis is under 4.0%. The weight is under 30g. These show that this flexible electrogoniometer has enough performance for clinical use.

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