Drugs which cure radiation poisoning. Instantly.
Radiation poisoning. It's not pleasant. But fear not! We have drugs that instantly cure Radiation poisoning, as well as reverse the symptoms, such as tumors and leukemia, and that pesky hair loss! Give or take a few days... Also, no side-effects! A Fantastic Drug which is used to clean out the user's system of all that nasty radiation, so they can get back to the action. Since radiation poisoning is a crippling condition, this is used as a Hand Wave to enable the writers to show a character suffering from it, but then be completely fine when the plot requires it. Alternatively, the plot can center around a character suffering radiation poisoning, and seeking this to rid themselves of the ailment.