Electronic safeguard systems are developed to provide wandering senile dementia patients a safe environment in their everyday life at home and special nursing homes. They are designed on the basic concept that the patients with declined mental capability may peacefully spend their rest time without any infringement of their freedom, which is most essential for their human dimity. The systems, which individually function to safeguard the patients against possible outdoor dangers, are connected to a network system through telecommunication lines. The system for the care of senile elderly patients at special nursing homes can be set up at any place near the enterances by utilizing power distribution or telecommunication lines without laying particular signal transmission cables. The system for the home care is designed compact with all the necessary functions including alarms. Informations about doors from which a patient goes out are transmitted to helpers at a distance by wireless interphone, FM-receiver or radio paging system. In addition, it is possible to guarantee the health and safety of patients by monitoring the operational state of each system at the center of operation with a network cooperation of helpers and neighbors through telecommunication lines. Thus, the helpers are ensured more released from physical and psychological burdens so that they can devote themselves to the care of senile elderly men, thereby improving their patients' comfort and human dimity.

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Impedance cardiography was performed on the cases with and without pulmonary edema. The thoracic resistivity (ρ-chest) was calculated from the assumtion that the thorax is a truncated corn shape. The value of ρ-chest was highest at 10kHz between 2kHz and 200kHz, while the pattern of response was almost same in all frequencies. This response was also same during extra-corporeal ultrafiltration method therapy. ρ-Chest was decreased significantly in the cases of pulmonary edema, and it showed high correlations with pulmonary capillary wedge pressure, hematocrit and body mass index, while Z₀ did not. As a conclusion, ρ-chest is a good index for diagnosing pulmonary edema, reflecting the change of thoracic tissue components.

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We studied the feasibility of quantitative texture analysis on two dimensional echoic images in 9 cases of resected gastric cancers in order to differentiate medullary type from intermediate type. 4 cases of medullary type and 5 cases of intermediate type were studied. The echo system we used had a linear arrey probe, and the central frequency of this was 7.5MHz. On examination, the parameters of the system (gain control, etc.) were usually on the same level, and we scanned at about 2.5cm distance from the regions. Regions of interest were set on echo images of cancer tissue. The texture analysis we used was the grey level difference method. As a result, the grey level difference distribution of medullary type was seen from that of interemedite type and the error rate of discriminant analysis was found to be 10%. We would expect the usefulness of this method to be evident in endoscopic ultrasonography.

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This paper proposes a new method to estimate a time varying acoustic transfer function of a heart by using the two acoustic transfer functions. One is a transfer function from the wall surface of a chest to the esophagus through a chest and a heart. The transfer function is estimated calculating the cross spectra between the applied vibration signal and the heart sound detected in the esophagus, each of which is picked up while the vibration is applied to the wall surface of a chest. The other transfer function also indicates the transfer characteristics from the wall surface of a chest to the esophagus through a chest and a heart. However, this transfer function is estimated from the two heart sounds simultaneously detected on the chest wall and in the esophagus while the vibration is not applied. By using these signals and the transfer functions between them, we obtain a transfer function of a heart by removing the influence due to the transfer function of a chest. This time varying transfer function of a heart obtained by the proposed method is available in various fields such as non-invasive measurement of internal pressure of a heart and medical treatments of hypertrophic cardiomyopathy and myocardial infarction.

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The study of blood flow measurement is important to understand the hemodynamics. Doppler ultrasound is a widely-used modality for the noninvasive study of flow. But there are a few limitations on measuring the blood flow, because only the changes observable by ultrasound along a profile beam are monitored and views are limited by the signal attenuation. A magnetic resonance (MR) imager provides full control of three dimensional relations between view and anatomy and may become a powerful tool for measuring the blood flow. In this article, we propose the new method for measuring the fluid flow by means of the magnetic labelling technique and evaluate the ability in the fluid flow measurement. The magnetic labelling technique is a method which can modulate the state of spins spatially in a field of view before imaging is performed. We design the new pulse sequence which has two radiofrequency pulses and the simultaneous gradient pulses of a phase encoding axis and a read out axis for our magnetic labelling technique. This sequence offers the ability to make striped or grid tags in a MR image arbitrarily. Stationary objects in a field of view have no a number of stripes are placed in a image. But moving object such as blood deform the shape of tage, and the deformation defends upon the velocity and the direction of moving or flow. The results of flow experiments with a phantom and an application to measuring the blood flow at the vena profunda femoris or the cerebral spinal fluid flow at the brain and the neck show that the flow velocity calculated from the deformation of tags corresponds with the true velocity and the velocity profile reflect its dynamics. The new technique proposed in this article is approved to be widely applicable to the blood flow measurement at any vessels and the cerebral spinal fluid flow measurement.

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Motivated by the fact that dark and indistinct endoscopic ultrasonoraphy (EUS) images are usually observed even if the region of interest (ROI) is situated on focal distances, we studied the influence of the angle between the center axis of the EUS and the surface of ROI (angle φ) upon the observed images. In order to investigate the influence of the angle φ, the phantom simulation and the experiment on the resected specimen were performed. In these simulations, the darkness and the indistinctness of EUS images were found to be caused by the angle φ. The results of experiments showed that the optimal angle, which yields distinct images, was within 15 degrees. We consider that the angle φ plays an important role in observing distinct EUS images. Proper adjustments are, therefore, necessary in the observation of tissue by using EUS.

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