Non-invasive ultrasonic urination sensor for ambulatory patient support

It is estimated that, in Japan, several million people suffer from urinary incontinence caused by, e.g., cerebrovascular disease, abdominal operations, spinal-cord damage, etc. Urinary incontinence is said to be a 'hidden' disease. When no adequate treatment is given, a serious situation may arise for both patients and their family. A non-invasive and unconstrained ultrasonic sensor has been designed enabling patients to discretely manage urination. The major problem of the sensor is how to maintain a proper irradiation angle to obtain an anteroposterior bladder diameter which corresponds to the actual bladder volume. Many types of ultrasonic probe holders have been tested and promising results have been obtained. The most practical, but as yet experimental, method is a four-element ultrasonic sensor, embedded in a flat probe.