Although researchers have made strides in targeted treatments, immunotherapy and chemotherapy for various types of cancer, in patients with glioblastoma, there is a major challenge that prevents these approaches from effectiveness: the blood-brain barrier. Johns Hopkins neurosurgeon Chetan Bettegowda explains that the barrier prevents all but the smallest molecules from entering the brain — protecting it from toxins and other chemicals that could damage it, but also blocking potentially lifesaving therapies from reaching their destination.

Now, Bettegowda and colleagues are investigating a new technique to treat glioblastoma, as well as other brain cancers and a host of neurological illnesses: magnetic resonance guided focused ultrasound, also known as MRgFUS. The Johns Hopkins team acquired the technology in November 2022 and was among the first in the country to do so.  

Using MRgFUS, Bettegowda and colleagues are researching how ultrasound beams may be concentrated to ablate targeted portions of the brain. The Food and Drug Administration has already approved the use of MRgFUS to treat movement disorders such as Parkinson’s disease. Clinical trials at The Johns Hopkins Hospital and elsewhere are also investigating use of MRgFUS for brain ablation to treat other conditions, such as epilepsy and brain tumors.

Via clinical trials, Bettegowda and colleagues are also testing MRgFUS’ potential to temporarily disrupt the brain-blood barrier. By delivering gas-filled bubbles into the bloodstream, the team is exploring how to use ultrasound energy directed by MRI to cause these bubbles to expand and contract, pressing against cells necessary for the barrier to remain intact — breaching it for several hours. The team hopes that during this time, physicians can take advantage of the open barrier to deliver targeted drugs, chemotherapies or immunotherapy agents.

Bettegowda adds that they are also looking into how to use a rift in the barrier to allow molecules released from tumors into the bloodstream to be harvested for liquid biopsies — a diagnostic and monitoring approach that he and his team have studied for years and are currently testing with MRgFUS in clinical trials.