This rupturing causes the cells to lose their contents and die. If enough cells are killed, functions associated with the cells cease. Death occurs because of the direct loss of vital organs or because of secondary infections resulting from the breakdown of the immune system. The effect depends on the dose of radiation received. Doses from 9 to 100 grays damage the gastrointestinal tract, causing nausea, vomiting, and diarrhea.
Progressive dehydration can result in death within several weeks.
This can lead to loss of appetite and hair, hemorrhaging, inflammation, and secondary infections such as pneumonia. These effects are also found in patients undergoing radiation therapy. Doses of less than 3 grays are rarely lethal, but cause symptoms that include loss of appetite and hair, hemorrhaging, and diarrhea. Long-term risks of radiation exposure center on the incidence of cancer and genetic mutations. Both effects have proven difficult to determine since cigarette smoking, diet, and sunlight exposure are also known to cause cancer and possibly to promote genetic mutations.