Only certain types of radiation are harmful to humans. For example, ultraviolet radiation can give people sunburns. X-rays and gamma rays can make a person sick, or even die, depending on the dose they get. Some types of particle radiation can also make people sick and lead to burns. If radiation does not carry high enough levels of energy, though, then these changes will not happen when something is hit by the radiation. This is referred to as non-ionizing radiation, which is not as dangerous.