Just how much can damaging radiation affect the human body?
On Tuesday, radiation levels were more than 400 millisieverts per hour near Fukushima's number 3 reactor.
A single dose of 1,000 millisieverts affects the intestinal tract causing nausea and vomiting.
At higher levels, radioactive iodine can destroy parts of the thyroid in the neck.
Intense exposure to radioactive material from 10,000 millisieverts per hour can cause immediate damage to small blood vessels and probably cause heart failure.
Professor Ilham Al-Qaradawi from Qatar University has revealed the effects of radiation poisoning:
"Radiation affects human cells. It either kills the cell--if the dose and energy are high, or it damages the cell, causing cancer and so on.
"When a person is exposed to radiation, the effect could range from redness in the skin to severe burning of the skin--but can also have more pronounced effects such as nausea.
"The long term effect of radiation is, of course, cancer.
"A large radiation dose or prolonged radiation exposure are the main reasons for radiation-induced cancer. The most common type is thyroid cancer, which can be combated by taking potassium iodide tablets, thereby saturating the body with iodine so it does not absorb the radioactive iodine if inhaled or ingested.
"There are also genetic, hereditary, effects and effects on the fetus in cases of high dose exposure.
"The effects of very high doses are seen in a very short time--in the order of minutes or hours depending on dose. The lower doses can give rise to cancer, but this might take years.
"It is believed that very low doses are harmless, since we are exposed to those naturally.
"It must be emphasized that fear of radiation is often as dangerous as the radiation itself, as it leads to unnecessary action that can be just as harmful."
Screen grab from Al Jazeera