Drugs that could fight cancer and other conditions in the brain have long been prevented from entering that tightly guarded place by the blood-brain barrier, a densely interlocked network of cells lining the brain’s blood vessels to screen out harmful substances. Recently, scientists at Sunnybrook Health Sciences Centre in Toronto broke through that cordon for the first time without using an invasive procedure.
Using focused ultrasound, researchers breached the barrier to deliver chemotherapeutic chemicals directly to a malignant tumor inside the brain. The group infused the pharmaceuticals and microscopic gas bubbles into a patient’s blood vessel near the affected site and then focused ultrasound at the tumor’s location. When the bubbles reached the sounding space, they vibrated and caused the blood-brain barrier to relax, letting the medicine through.