Ultrasound standoff optimization for maximum image quality of a robot-assisted flat-panel ultrasound device

Ultrasonography is a widespread intraoperative imaging modality. However, it suffers from several shortcomings e.g. its dependance on the skills of the operator for the image quality. To overcome this shortcoming, Gumprecht et al. [1] recently proposed a new robot-assisted flat-panel ultrasound device for continuous intraoperative imaging during laparoscopic tumor resection in urology. This device is integrated in the OR-table and performs its imaging through the back of a supine patient. The ultrasound probe resides in a tank, filled with a fluid that is traversable by the ultrasound waves. A flexible membrane is stretched over the tank and is in contact with the fluid and the patient. Through is flexibility, the membrane can adapt to the shape of the patient. Therefore, the membrane assures for sufficient coupling of ultrasound waves into the patient. We based the selection of the membrane and the fluid upon the quality of the ultrasound images that can be recorded with this combination. In this paper, we present the results of the experiment that lead to the standoff used in the robotic device of Gumprecht et al. [1].