| The development of real-time three-dimensional (RT3D) ultrasound imaging for endoscopic procedures can improve diagnostic imaging as well as serve as a guidance and assessment tool for surgeries and other interventional purposes. This work describes the development and fabrication of an endoscope-based device that is capable of RT3D ultrasound imaging and the testing of this device as an instrument for diagnosis, guidance, and therapy in a variety of clinical applications.; The first steerable endoscopic RT3D probe was constructed for the Volumetrics Medical Imaging (VMI) scanner. The device is 1cm in diameter and was fabricated on a multilayer flexible interconnect circuit designed for 504 elements in a 6.3mm x 6.3mm aperture. Incorporation of high density ribbon cabling enabled the high channel count of the transducer. This device, operating at 5MHz, was tested to have an average -6dB bandwidth of 25.3%.; The completed probe was used to image in vivo canine anatomy, specifically the heart, esophageal wall, liver, and prostate. Real-time 3-D transesophageal scans provided clear visualization of the heart valves, coronary sinus, and pulmonary veins. Panoramic 120° scans with the endoscopic device demonstrated the utility of the probe for interventional guidance in electrophysiological procedures. For laparoscopy, the probe was also used successfully in post-mortem canine studies integrating coordinates acquired from the ultrasound scans with a robot linear motion system to direct a needle to targets in abdominal organs. In vitro and post-mortem experiments with the robot demonstrated an average guidance error of less than 2mm.; The probe was also used to determine the feasibility of combined endoscopic RT3D ultrasound and hyperthermia. Acoustic field simulations and finite element analysis of the probe have shown that intensities of over 3.43 W/cm 2 are required to induce temperature rises in tissue of 4°C at a 3cm focus. With modifications to the VMI scanner, the probe produced 2.40 W/cm2 using 8 cycle bursts at a pulse repetition frequency of 8 kHz, yielding a maximum ex vivo temperature elevation 2.3°C.; In addition, in order to increase the field of view close to the transducer face, the first cylindrical curvilinear matrix array for RT3D ultrasound was developed. |
