A DISCOVERY WORTH SHARING◎Human Body & Psychology↗ A radioactive tracer can make brain activity visible Positron emission tomography (PET) scans create pictures of the living, active brain. An individual receiving a PET scan drinks or is injected with a mildly radioactive substance, called a tracer. THERE’S MORE TO DISCOVERReady for another?One small break. A fresh perspective.Get today's Breakfact ↗ OpenStax · Psychology 2e · The Brain and Spinal Cord ↗ (opens in a new tab)Share ↗