A semi-automated handheld active needle device for percutaneous image-guided interventions

Abstract

This thesis presents the design and preliminary evaluation of novel brachytherapy (BT)systems intended to improve anatomical conformity, placement precision, and procedural safety in high-dose-rate (HDR) treatments for prostate and cervical cancer. Traditional applicators often rely on rigid, manually inserted components, which limit adaptability and reduce dose accuracy in patients with complex anatomical and disease variations. To address these limitations, a semi- automated active needle system was developed for prostate HDR BT, integrating a custom 3D- printed template and preplanned curvilinear trajectories based on patient-specific magnetic resonance imaging (MRI) data. Phantom and air testing demonstrated sub-millimeter tip displacement accuracy, validating the system’s precision. Building on this foundation, a handheld tendon-driven steerable needle device was created for real-time use under transrectal ultrasound (TRUS) guidance. This system features a joystick-controlled actuation mechanism and a modular TRUS attachment to support intraoperative visualization and navigation. For cervical cancer treatment, a modular applicator was designed incorporating adjustable vaginal spreaders, a controllable tandem channel, and support for 2 mm steerable needles. The design accommodates ovoid separation from 25 mm to 45 mm. The performance and range of motion were validated for TRUS imaging compatibility. Future development will focus on interfacing the cervical applicator with externally controlled telescopic pre-curved tandems and incorporating mechanisms for active adjustment of ovoid geometry. Collectively, these systems demonstrate the feasibility of integrating flexible, image-guided instrumentation into HDR BT workflows, offering a pathway toward more personalized, precise, and patient-specific cancer treatment solutions.