Happy birthday to Kary Mullis, whose work on polymerase chain reactions allows us to easily amplify segments of DNA, and helped usher in the modern age of genetics and genomics. Learn more about PCR with our animation. http://bit.ly/pcrvideo | BioInteractive

A positron emission tomography (PET) scan is a unique type of imaging test that helps doctors see how the organs and tissues inside your body are actually functioning. The test involves injecting a very small dose of a radioactive chemical, called a radiotracer, into the vein of your arm. The tracer travels through the body and is absorbed by the organs and tissues being studied. Next, you will be asked to lie down on a flat examination table that is moved into the center of a PET scanner—a doug