Scientists from Stanford have used lab made gold nanoparticles to highlight malignant tissue in the brain so surgeons can easily cut out tumors while leaving the healthy bits just fine.
The gold orbs are injected into the patient and then left to bleed out through leaky blood vessels in pats of the brain damaged by the tumor. That's when they get stuck in the bad tissue itself, marking it out for the scalpel when viewed with the right imaging.
Gold has its use after all! And not just for making you look rich.