Tuesday, May 1, 2007
I am radioactive man. At times, at least. About every six months I go to a specialized radiology clinic to get a positron emission tomography scan. After starving myself overnight, the technician removes a syringe full of fluorodeoxyglucose from a lead box and injects it into my arm. The glucose-hungry parts of my body such as brain, kidney, and cancer cells consume the fluorodeoxyglucose for energy.
The fluorine (colored green) in fluorodeoxyglucose has an extra neutron, making it unstable and prone to radioactive decay. Every 110 minutes, half of the fluorine atoms emit positrons to transmute into stable oxygen. The positrons zip through my body for a few millimeters until each collides with an electron. Upon collision the positron-electron pairs of particles annihilate each other and emit two gamma rays moving in opposite directions.
During this time, I lay on a mechanized platform that slowly slides me through a detector tunnel. As the gamma rays shoot out from my body the detector notes their position and trajectory. Then a computer compiles the data and constructs a three-dimensional map of the metabolic activity in my body.
I don't feel anything physically except for hunger and muscle cramps from lying still for two hours. But I like to imagine that all of the X-rays, gamma rays, and poisons are imbuing me with super powers.