Development and validation of MRI compatible pediatric surgical robot with modular tooling for bone biopsy

Abstract

In clinical practice, magnetic resonance imaging (MRI) is used to locate a lesion/tumor for bone biopsy in children. However, there is a lack of MR-compatible tools that can be used simultaneously during imaging and biopsy while maintaining surgical accuracy and safety. The Pediatric Surgery Robot (PSR) platform is a 5-DOF robot with a modular tool interface. For the case of bone biopsy, a Bone Biopsy Tooling (BBT) is attached. It is designed to fit within a Philips Achieva 3.0T MRI bore and carry a modified titanium bone biopsy needle. A surgical pre-planning and control interface has been developed for joint and Cartesian level control. The PSR-BBT has demonstrated 1.65 +/- 1.77 mm accuracy in Cartesian control in free space. The PSR-BBT can generate 12.46 +/- 0.32 N of axial force while drilling at a speed of 30 rpm, which is sufficient for cortical and cancellous bone phantoms. Under MRI testing (T1-FFE, T1-SE, T2-FFE and T2-TSE scans), the system demonstrated less than 33% signal-to-noise ratio variation while drilling and a 0.46% geometric distortion while powered on without significantly impacting MRI guidance in situ. These results show that the PSR-BBT can allow the user to simultaneously image and perform the biopsy and presents the PSR as a viable platform for MR-guided robotic surgery.