Towards Safe and Collaborative Robotic Ultrasound Tissue Scanning in Neurosurgery

TL;DR

The paper tackles the challenge of adopting intraoperative ultrasound in brain tumor surgery by introducing a robotic iUS tissue-scanning platform that unifies automatic object localization, real-time surface reconstruction, and impedance-guided probe navigation. The approach combines ArUco marker-based localization, RGB-D-driven triangular-mesh surface modeling, and a collaborative impedance controller to enable autonomous, teleoperated, or hands-on scanning along tissue surfaces. Key contributions include a hardware interface that obviates external tracking, a soft-tissue phantom for testing, and an integrated control loop that embeds surface geometry into probe navigation. Preliminary experiments on a brain-like phantom demonstrate feasible probe landing and low-force, tunable coupling, indicating potential to reduce operator workload and improve reproducibility in neurosurgical iUS workflows. If validated further, this framework could enhance real-time tissue characterization and support maximal safe tumor resection by enabling safer, more consistent iUS data acquisition in the operating room.

Abstract

Intraoperative ultrasound imaging is used to facilitate safe brain tumour resection. However, due to challenges with image interpretation and the physical scanning, this tool has yet to achieve widespread adoption in neurosurgery. In this paper, we introduce the components and workflow of a novel, versatile robotic platform for intraoperative ultrasound tissue scanning in neurosurgery. An RGB-D camera attached to the robotic arm allows for automatic object localisation with ArUco markers, and 3D surface reconstruction as a triangular mesh using the ImFusion Suite software solution. Impedance controlled guidance of the US probe along arbitrary surfaces, represented as a mesh, enables collaborative US scanning, i.e., autonomous, teleoperated and hands-on guided data acquisition. A preliminary experiment evaluates the suitability of the conceptual workflow and system components for probe landing on a custom-made soft-tissue phantom. Further assessment in future experiments will be necessary to prove the effectiveness of the presented platform.

Figures (5)

• Figure 1: Experimental setup showing the robotic arm holding US probe and camera next to the US machine, scanning a brain phantom. A SpaceMouse® can be used to telemanipulate the US probe. DLR/Alexandra Beier (CC BY-NC-ND 3.0)
• Figure 2: Workflow for our iUS tissue scanning platform. (1) Automatic detection of the object's location using ArUco markers; (2) RGB-D reconstruction (with ImFusion) of phantom surface with a stereo camera results in a triangular mesh; (3) Incorporation of mesh geometry into the real-time control loop; (4) US probe guidance for contact establishment and tissue scanning. Note that the upper half of the brain being fully exposed in this image is merely for the purpose of visualisation. In reality, the craniotomy will be much smaller.
• Figure 3: (a) Frames: $\{\mathcal{B}\}$ robot base, $\{\mathcal{C}\}$ camera, $\{\mathcal{P}\}$ US probe, $\{\mathcal{O}\}$ object. (b) Custom-made brain phantom with sample US image.
• Figure 4: Collaborative robotic tissue scanning controller.
• Figure 5: Interaction force between US transducer and brain phantom during contact establishment. The US images below were recorded during the interaction and show qualitatively different stages of US contact.