Robot-assisted catheter placement with novel shape-sensing stylet to facilitate adaptive image guided pelvic brachytherapy - Project Summary Gynecologic malignancies accounted for over 114,810 new cancer cases and approximately 35,640 deaths in 2023 in the United States. Brachytherapy has been used to treat locally advanced cervical and endometrial cancers since the early 20th century and is now part of the standard of care. Brachytherapy involves the precise placement of short-range radioactive sources near or in direct contact with the tumor through thin catheters, enabling high radiation doses in the target volume with rapid fall-off to protect adjacent normal structures. Today, high-dose-rate (HDR) brachytherapy is commonly employed along with a computer-controlled remote afterloading system, which allows accurate control of radiation dose for each catheter by adjusting the “dwell time.” Though computer-controlled afterloading systems are widespread, the quality of brachytherapy is still limited by suboptimal catheter placement. Clinicians often struggle to properly deploy the catheters in the target volume because of the deviation of the catheters from the intended path during insertion and lack of quantitative catheter position feedback or the dosimetric consequences resulting from the current catheter locations. Intraoperative imaging, either computed tomography (CT) or magnetic resonance (MR), potentially provides such feedback and allows for “adaptive catheter placement,” where the clinician adjusts catheter location until optimal dosimetry is achieved. However, adaptive catheter placement is not practical in the current form because it requires iterative implantation and imaging; each iteration involves positioning of the patient for imaging and catheter placement and moving of the clinician between the imaging room and the control room. To enable adaptive catheter placement in a wide range of clinical settings, we will develop a catheter placement manipulator system that combines (1) a state-of-the-art fiber-optic shape-sensing stylet to obtain real-time quantitative measurement of the catheter trajectories in the patient, and (2) a teleoperated catheter placement manipulator to shorten the turnaround time for catheter placement and evaluation, (3) a visualization framework that provides quantitative measures of a catheter’s deviation from its intended trajectory and real-time evaluation of the consequences to the achievable radiation dose distribution. We hypothesize that the combination of real- time catheter trajectory digitization and quick catheter insertion will allow adaptive catheter placement, where the catheter locations are optimized through frequent iteration of the plan-insert-check cycle with real-time quantitative dosimetry feedback, leading to optimal radiation dose distribution. We will pursue the following specific aims: (Aim 1) Develop a fiber-optic shape-sensing stylet for real-time catheter tracking to achieve real- time tracking and prediction of the catheter trajectory for real-time feedback; (Aim 2) Develop a teleoperated catheter insertion manipulator for quick catheter placement to achieve a shorter turnaround time for the frequent plan-insert-check cycle; (Aim 3) Develop, optimize, and validate the system for teleoperated adaptive catheter placement to test the impact of teleoperated adaptive catheter placement for optimal dose distribution.
