MRI-guided robotics moves bone biopsy innovation into clinical care - Children's National

Bone biopsy can be essential when clinicians need a tissue sample to diagnose a suspicious lesion. Conventional image-guided procedures may rely on ionizing radiation to help physicians reach the target. A novel approach, led in part by Kevin Cleary, PhD, associate director of Engineering at the Sheikh Zayed Institute for Pediatric Surgical Innovation at Children's National, instead uses magnetic resonance imaging (MRI).

MRI provides detailed images without exposing the patient to ionizing radiation together with a robot that positions and locks a needle guide on the planned path.

At the 15^th Interventional MRI Symposium, Dr. Cleary shared how MRI-guided robotics are opening new possibilities for precise, radiation-free interventions during an invited talk. His presentation highlighted an MRI-safe robot and drill developed by researchers at Children's National and Johns Hopkins University to support bone biopsies in children. After a successful first clinical case, the team has now used the technology in a second patient, also with positive outcomes.

Engineering designed for the MRI environment

Working safely around a powerful magnetic field requires a system built without conventional electric motors or metal components that could interfere with imaging. The robot uses air pressure for movement and optical sensors for precise position feedback. Clinicians manually place the device over the area of interest, while motorized axes orient the needle guide toward the target and set the planned insertion depth.

The workflow is designed to combine the strengths of real-time clinical judgment and image-based precision. The patient can be moved into the scanner for targeting and confirmation, then out of the scanner while the biopsy is performed through the guide locked on target. This setup gives the clinical team room to complete the procedure while preserving the trajectory established from the MRI images.

The big picture

In the first clinical case, the system was used to biopsy a marrow-replacing lesion in the right femur of an 8-year-old patient. MRI images helped the team identify the target and skin entry point, register the robot to the images and align the needle guide. With the patient removed from the scanner, clinicians used the pneumatic drill and a commercial biopsy kit to collect three core samples. A follow-up MRI confirmed the biopsy path and sampling location.

The procedure was completed successfully in less than two hours in the MRI suite, without complications. Pathology provided a definitive diagnosis of juvenile Paget's disease, a rare condition. The second successful patient experience added encouraging early evidence that the workflow can be repeated as the pilot clinical trial continues.

Why it matters

The early clinical results show the feasibility of bringing MRI-guided robotic assistance into a pediatric procedure that demands accuracy. By helping clinicians reach a specific target while avoiding ionizing radiation, the platform could support a safer and more precise approach for patients. The work also demonstrates how engineers, radiologists, surgeons and other clinical specialists can collaborate to translate a device from design and testing into patient care.

The MRI-safe bone biopsy system was developed through a collaboration between Children's National, led by Karun Sharma, MD, PhD, interventional radiologist, and the Johns Hopkins University Urology Robotics Program led by Dan Stoianovici, PhD. The work was partially supported by the National Institutes of Health under grant R01CA172244