Researchers have identified a crucial metric known as the acoustic emission dose, which could revolutionize the way drugs are delivered to glioblastoma patients by safely opening the blood-brain barrier (BBB). This discovery, made by a team at Mass General Brigham in collaboration with the University of Maryland School of Medicine (UMSOM), leverages focused ultrasound technology to enhance drug delivery to the brain.
The blood-brain barrier, a protective feature of blood vessels, serves as a formidable obstacle in treating brain cancer due to its efficiency in blocking harmful substances. However, this same feature complicates the delivery of therapeutic agents to the brain. For decades, researchers have been exploring focused ultrasound—a technique combining low-power ultrasound with microbubbles—as a means to temporarily open the BBB.
Breakthrough in Focused Ultrasound Research
In a recent study, researchers analyzed data from ultrasound treatments administered to 23 glioblastoma patients. The study, published in the journal Device, highlights the acoustic emission dose as a predictive measure for safely opening the BBB. This metric identifies an optimal range, or “sweet spot,” which the researchers used to treat patients effectively.
“Our study builds on seminal work that began back in the 1990s in the Focused Ultrasound Lab at Brigham and Women’s Hospital when focused ultrasound combined with microbubbles was first used to open the blood-brain barrier,” said Dr. Alexandra J. Golby, senior author and a member of the Departments of Neurosurgery and Radiology at Brigham and Women’s Hospital. “Our work builds upon these discoveries, translating pre-clinical work into humans, and showing the promise of using this technique in patients with glioblastoma.”
The research team conducted 972 individual applications of focused ultrasound sonications across 58 treatments, assessing the acoustic emission dose—a signal from microbubbles that can be adjusted to open the BBB. They determined that an acoustic emission dose of 0.5 to 1.6 is optimal for safely opening the BBB, allowing for targeted drug delivery while minimizing potential damage.
Implications for Glioblastoma Treatment
The implications of this study are significant for glioblastoma patients, who often face limited treatment options. Focused ultrasound offers a non-invasive method to enhance drug delivery, potentially improving outcomes for patients with this aggressive form of brain cancer.
“Acoustic emissions monitoring and acoustic emissions dose offer an opportunity for a unifying concept in focused ultrasound,” stated Dr. Graeme Woodworth, lead author and professor and chair of Neurosurgery at UMSOM. “The data and analysis provided in this study serve to advance this methodological paradigm and the focused ultrasound field.”
While the current study identifies a therapeutic window for BBB opening, the team plans to report separately on the safety and effectiveness of focused ultrasound treatments in the study’s 23 patients. The findings underscore the potential of this technique to transform glioblastoma treatment by improving drug delivery to the brain.
Future Directions and Research
As the research progresses, the focus will likely shift towards refining the technique and exploring its applicability to other neurological conditions. The promise of focused ultrasound extends beyond glioblastoma, with potential applications in treating Alzheimer’s disease, Parkinson’s disease, and other brain disorders.
Dr. Golby emphasized the importance of continued research in this area. “Our study shows that we can successfully and repeatedly open the blood-brain barrier for treatments,” she noted. “This represents an important advancement for a patient population that often has few treatment options.”
As researchers continue to explore the possibilities of focused ultrasound, the hope is that these advancements will lead to more effective and less invasive treatment options for patients with brain disorders, ultimately improving their quality of life and survival rates.
