Jointly with the SMK Corporation, an electronic components manufacturer, headquartered in Tokyo, the Kindai University research group developed a system to detect micro vibrations of the body using extremely high frequency (EHF) electromagnetic waves with wavelengths of only several millimeters, referred to as “millimeter waves.”
The Kindai group recognized that sensors for millimeter waves are relatively inexpensive, and as such are widely used (without much recognition) in the management of animals’ health, in the monitoring of plant facilities in high-temperature environments, and in security systems, vehicle safety devices, etc.
In its work, the research group determined respiratory movements of 20 volunteers using a millimeter-wave sensor developed by SMK. Millimeter waves were emitted to each subject’s thorax and abdomen, after which the movement of their body surface was visualized as a waveform based on the reflected waves. This was compared with conventional methods.
The technique was able to accurately determine respiratory movements of babies and small children—traditionally difficult to ascertain. Additionally, stable measurements were confirmed both when subjects were lying on their backs for a CT scan and standing for an X-ray.
It can be difficult or impossible for a technician to tell a baby or small child to “stay still” or “hold your breath,” complicating the effort toward an accurate diagnosis. Moreover, the assessment of respiratory motion by visual observation depends greatly on each technician’s experience and expertise. In addition, making patients partially undress can cause embarrassment, which is another concern.
The following features were noted by the research group as advantages of the new system:
- Easy installation with existing X-ray and CT equipment.
- Substantially reduced costs in comparison with conventional respiratory monitoring devices.
- A lighter burden on patients expected because of the reduced need to repeat procedures (X-rays and scans).
- Improved quality of associated medical treatments expected due to enhanced diagnostic accuracy.
Given the potential of more accurate radiotherapy through the monitoring of respiratory motion in real time, the group plans to continue further applied research.
