X-rays and gamma rays can cause a number of other problems besides cancer. What problems occur depends on factors such as the radiation dose, the timing of the exposure, and what areas of the body are exposed.
Exposure to high doses of radiation over a short period of time can cause radiation sickness (sometimes called radiation poisoning or acute radiation syndrome) and even death. Some of the symptoms of radiation sickness include fainting, confusion, nausea and vomiting, diarrhea, hair loss, skin and mouth sores, and bleeding. The atomic bomb blasts in Hiroshima and Nagasaki led to many cases of radiation sickness. Some cases have also resulted from nuclear power plant accidents, such as the one in Chernobyl.
Doses of radiation such as those given in radiation therapy also cause side effects.
Short-term side effects depend on the area being treated but might include skin changes (ranging from mild reddening to something like a severe burn), nausea, vomiting, diarrhea, and low blood cell counts.
There is also a risk of long-term side effects, which again vary depending on the area being treated. For example:
Lower doses of radiation, such as from imaging tests, are not known to cause short-term health problems.