A novel high-frequency endoscopic ultrasound system for colorectal cancer diagnosis

Colorectal cancer (CRC) is the third most common cancer for both men and women in the US, predicted in 2012 to account for 9% of new cases and cancer related deaths. Endoscopic ultrasound (EUS) has been widely used to assess tumor penetration and metastasis risk for determining the treatment strategy. With high-frequency transducer (20MHz-30MHz), EUS is capable of delineating the mucosa-submucosa layer of normal human colon with micron-scale resolution anatomical information; however, the current high-frequency EUS is still insufficient to distinguish cancer from polyp and adenoma due to the lack of patho-physiological information. An open high-frequency EUS system, compatible with regular endoscope, which allows acquisition of radio frequency (RF) data for acoustic tissue characterization and combination with other functional imaging modalities (e.g. photoacoustic imaging) may bring values to diagnose early stage colorectal malignancies. This system includes a miniaturized 30.5 MHz single element side-view transducer using PMN-0.28PT single crystal, low noise electronics, and a high-performance Field Programmable Gate Array as a core microprocessor to accomplish flexibility, diversity, and real-time imaging. Phantom testing and ex vivo animal imaging were conducted to demonstrate the system performance.