Development of a Low Resource Capsule type Ultrasound Endoscopic Probe with Coded Excitation

Abstract

In the treatment of esophageal cancer, a quantitative diagnosis of the cancer stage is essential in providing suitable treatment for patients. However, optical endoscopes which image only the surface of the tumor or computed tomography (CT) scans which damage the body are not suitable diagnostic tools. Alt-hough ultrasound endoscopy is suitable for imaging the cancer’s growth depth into the esophagus, the con-ventional system requires an experienced clinician to insert a large tube into an organ and is highly likely to damage the patient’s esophagus. Recently, to overcome this limitation, various research groups have been studying the capsule type ultrasound endoscopy system, but these are too large for humans to swallow or inappropriate for diagnosis due to low image resolution. To overcome the shortcomings of the capsule type ultrasound endoscope, we developed a small capsule endoscope structure using a reflector and evaluated a signal improvement technique suitable for low voltage. This system minimizes the inter-nal rotation structure through the micro-stepping control of a small step motor, and the performance is compared using coded excitation techniques to optimally obtain a signal at a low voltage. This system has the smallest length compared to existing capsule endoscope modules, and it is possible to secure multiple ultrasound image scan lines through a step motor. Also, through the coded excitation technique, the relative performance of the spatial resolution and signal-to-noise ratio (SNR) of the image according to each tech-nique could be compared in a low-voltage environment. This system showed improvement of low-voltage image performance through miniaturization and signal improvement techniques suitable for insertion into the body of the capsule type ultrasound endoscope system, suggesting that the image improvement through the low-voltage technique can be miniaturized using an appropriate structure. By presenting the advantages and disadvantages of the ultrasound signal improvement technique, suggest the information to enhance imaging depth for developing capsule type ultrasound endoscope.