In 1961, chemists at Brookhaven National Laboratory (BNL) studied how to detect small brain tumors by analyzing the decay of radioactive material injected into the patient’s bloodstream and preferentially absorbed by the tumor. To help them, BNL’s Instrumentation Division built different arrays of detectors, and this circular type proved best. In the 1970’s, BNL helped reconstruct the raw data received by the detectors into an image of the working brain. This breakthrough led to more practical devices for imaging areas of the brain: today’s PET machines. Today, Brookhaven is a leader in addiction research. Today, BNL uses PET technology to study major areas of medical research including, drug and alcohol addiction; the development of a new strategy for addiction treatment; obesity and eating disorders; attention deficit hyperactivity disorder (ADHD); aging and neurodegenerative disorders.