Health and Medicine

This Is What High Doses Of Radiation Actually Does To The Human Body


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockMar 17 2018, 21:58 UTC

You get more radiation by sleeping next to two people than by living within 80 kilometers (50 miles) of a nuclear power plant. This just a fact, we are not kink-shaming. vlastas/shutterstock

Pop culture and the media often turn radiation into a scarecrow for technology that humanity can’t or shouldn’t control. In reality, radiation is not to be feared. This is because it is an umbrella term, with radiation constantly around us in one form or another and most of it safe. So let’s take a critical look at this fascinating and important area of science and its effects on the human body.


Radiation in physics is defined as the emission or transmission of energy in the form of a wave or a particle. This means all the light in the universe is radiation, technically known as electromagnetic radiation. The particles thrown into space by stars are also radiation. Same goes for the particles released in nuclear reactions. But not all radiation is created equal.

Every instant we are surrounded by a huge amount of harmless radiation (neutrinos, visible light, etc.) and only very rarely do we get exposed to something that could be dangerous. For example, 100 trillion neutrinos go through your body every second. To truly understand the repercussions of radiation, we need to consider the amount a person is exposed to and the duration of that exposure. 

The worrying point with radiation is the ability for particles of a certain energy to ionize molecules in our body, especially water. This can damage cell components that are crucial to life. Radiation can break bonds in molecules that lead to changes in the structure of proteins and damage DNA. Cells have safeguards in place to repair themselves and are often very efficient at that, but sometimes this is not enough.

A high enough dosage of radiation can kill cells. And once enough cells have died, organs begin to fail. Radiation has been linked to seizures and heart problems from damaged blood vessels. It can also harm the digestive system, leading to diarrhea and vomiting blood. It can make people sterile, it can debilitate the immune system, and it causes skin lesions and burns. For medium doses, the damage might not be immediately apparent, but it could result in a higher risk of cancer later in life.


The dose of radiation is measured in sieverts. One sievert is considered the value at which one would become ill; receiving eight sieverts of radiation all at once would result in death. Those might seem like scary numbers but they are not. The average person receives about one-quarter of a sievert over their lifetime. The “danger” values are indicative, rather than exact. Acute radiation syndrome is a complex condition and the values don’t always translate to equal ailments in all cases.

The knowledge we have of the most extreme effect is due to a controversial medical study on Hisashi Ouchi, who in an accident in 1999 was likely exposed to the highest level of radiation any human has experienced. He was kept alive for 83 days against his will while in terrible pain. 

He received in a fraction of a second 17 sieverts of radiation – over double what is believed to be the fatal dosage and 340 times more than the maximum dosage a nuclear site worker in the US can be exposed to over a year. People have estimated that the amount of ionizing radiation (not energy) was comparable to the hypocenter of the Hiroshima nuclear bomb explosion. In a book detailing the aftermath of the accident, it is stated that Ouchi’s chromosomes were broken and scrambled beyond recognition.


A less horrifying but equally important case happened in Russia in 1978. Scientist Anatoli Bugorski was hit in the head by a proton beam while checking a malfunctioning piece of equipment. He received more than 8 sieverts of radiation. He is reported to have said he saw a flash brighter than a thousand Suns, but felt no pain. The left side of his face swelled beyond recognition and the doctors thought he would die within a few days. But he didn’t. He lost hearing in his left ear and that side of the face was left paralyzed (and also wrinkle free). However, he recovered and even completed his PhD.

These two examples are extreme cases of what radiation can do to the human body, but they shouldn’t make us fearful of nuclear technology. Radiation has a wide range of applications in medicine. The most common use is probably X-rays, which let us look inside the body. Radioactive elements are also used to treat cancer and understand certain biological functions. Even particle beams, not too dissimilar to the one that almost killed Bugorski, have their uses in medicine. Proton therapy is also used to kill tumors.

When we think of radiation we often think of nuclear disasters like Chernobyl and Fukushima, but nuclear energy production remains one of the safest methods to generate electricity.

Cherenkov radiation glowing in the core of the Advanced Test Reactor. Argonne National Laboratory.

"Nuclear power is an effective generation source for 11 percent of global electricity and is reasonably safe. Safety can be compared across electricity generation sources using their 'deathprint' (deaths per trillion KWh), with nuclear scoring 90 compared to the 100,000 of coal,” Dr Ben Britton, deputy director of the Centre for Nuclear Engineering at Imperial College, told IFLScience.

Nuclear is better than renewable resources such as solar (deathprint = 440 deaths per trillion kWh) wind power (150), and hydroelectric power (1,400). There is a lot of regulation keeping nuclear power plants running safely. For example, if you live within 80 kilometers (50 miles) from a nuclear power plant, you get about 0.09 microsieverts every year, which is less than twice the amount you get from sleeping next to someone (0.05 microsieverts). Please don’t take this as "being single saves you from radiation."

Most forms of radiation are harmless to us – and yes, a few are dangerous. But we can use it to make the world cleaner and ourselves healthier. It is important to understand radiation without fear or prejudice.


Update: The original version of this article linked to a blog post (Trigger warning: extremely graphic images) that claimed it showed images of Hisashi Ouchi after his accident. That claim has now been debunked in a video (TW: extremely graphic images) and a Reddit thread


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