oa Design of Steering Mechanism for Automated Cystoscopy

Urinary bladder cancer is one of the most common cancers worldwide and has a high recurrence rate. It has the highest lifetime cost of care per patient due to long follow-up cystoscopic surveillance after surgery to detect the high risk of recurrence.

This research develops a portable custom cystoscopic procedure to improve the efficiency and accuracy of the bladder cancer surveillance. The system uses a segmented bending mechanism that is inserted into the bladder via the urethra to steer a flexible imaging probe to provide a comprehensive diagnostic tool for review by an urologist as illustrated in Fig. 1. The position and orientation of the camera locating at the tip of the probe can be automatically controlled remotely to scan the entire bladder surface.

The structure of the bending segment is shown in Fig. 2. The segment bending is tendon driven. Four distributed small wires are connected to the segment body via guiding rings. The wires to control the distal segments are also guided through the mechanism via the rings of proximal segments. The bending angle and bending direction of a segment can be controlled by pulling and releasing its four wires accordingly. The design of the mechanism and the forward/inverse kinematics simulation were finished. A mockup model is under construction to verify the proposed design.

Images abstracted from the video are used to reconstruct a 3D panorama of the whole bladder surface. Our 3D and image mosaicking software is under developed by our collaborator at University of Washington, USA.