A lightweight portable ultrasound robot for autonomous liver sonography

Autonomous ultrasound robots could improve access to liver disease screening but remain limited by anatomical variability, respiratory motion and bulky hardware. Here, we present a lightweight robotic liver ultrasound system with a 588-g decoupled end-effector controlled by a sonographer-informed AI agent. The robot attaches directly to the abdomen, maintaining stable force and controlled motion during breathing and patient-side disturbances. Trained on sonographer trajectories, the agent integrates spatial, tactile and visual feedback to navigate discontinuous acoustic windows and acquire standard imaging planes. Evaluations in 102 healthy participants and 17 patients yielded clinically interpretable images and anatomical measurements closely matching clinical references. We also deployed the system for hepatic echinococcosis screening in a high-altitude, low-resource setting on the Qinghai-Tibet Plateau and evaluated its performance in dynamic scenarios, including vehicle-based scanning. These findings support portable, patient-mounted robotics for standardized ultrasound beyond specialist settings. Liver ultrasound is operator-dependent. Here, the authors develop a lightweight, patient-mounted robot for autonomous liver scanning in clinical, remote and mobile settings, with results comparable to those gathered by experienced sonographers.