Transperineal ultrasound image guidance system for robot-assisted laparoscopic radical prostatectomy

Prostate cancer is the most prevalent form of male-specific cancer. Minimally invasive robot-assisted laparoscopic radical prostatectomy, or the surgical removal of the prostate using the da Vinci surgical system, has become the most common treatment for organ-confined prostate cancer. Compared to traditional open surgery and laparoscopic surgery, the da Vinci system provides stereoscopic vision and high tool dexterity while also minimizing risk of infection and patient recovery times. However, this is still a difficult procedure for the surgeon, as there is often a trade-off between complete removal of cancerous tissue and preservation of structures responsible for maintaining urinary and sexual function. Delineating between these structures and cancerous tissue in a visually homogeneous workspace requires a high level of expertise. This thesis evaluates the feasibility of using transperineal ultrasound for image guidance to improve visualization of anatomical structures and cancer localization during robotic prostate surgery. The proposed image guidance system utilizes a matrix array ultrasound transducer capable of real-time imaging the prostate anatomy in 3D. A calibration method is detailed to register the ultrasound volume to da Vinci robot kinematic frame. In dry lab experiments, calibration error was determined to be 0.84±0.49mm. Next, using a deformable finite element model-based deformable registration, annotated preoperative MRI is registered the ultrasound volume for intraoperative visualization of cancerous lesions. A virtual surgical scene containing the prostate is rendered in 3D to the da Vinci surgeon’s console, where the surgeon can use the surgical instruments to traverse the virtual prostate volume and view the axial MRI slices. To evaluate this registration pipeline from MRI to ultrasound to da Vinci system, a prostate phantom was used to test a user’s ability to locate targets in the registered prostate volume. Overall target registration error was 2.55±0.94mm. To evaluate clinical feasibility, an exploratory study was conducted to determine the efficacy of transperineal imaging during standard robotic prostatectomy. Prior to surgery, the ultrasound transducer was placed on the perineum, and the patient anatomy, including prostate and surrounding structures, was monitored throughout the procedure. Results from four patient cases showed good delineation of the prostate and other anatomy.Applied Science, Faculty ofBiomedical Engineering, School ofGraduat