There is a perfect defensive mechanism to keep toxins away from your brain: blood - brain barrier. But this does not allow border guard medicines to enter the brain. This leads to a serious problem in the treatment of tumors and other diseases.
In November 2016, a team at the Sunnybrook Health Sciences Center in Toronto leaked this system by creating new entrances. The doctors injected microscopic air bubbles into the bloodstream of a cancer patient, then sent sound waves focused on blood vessels near the tumor. This caused the bubbles to vibrate violently and cause large holes in the blood brain barrier to open only where the chemotherapy drug can pass. These holes closed in a few hours. The method may allow targeted drug treatment for diseases such as Alzheimer's or Parkinson's. "A cosmic world full of new possibilities is pre-empting," said Todd Mainprize, a neurosurgeon who is the chief researcher of the team. "We can treat things we can not treat before."