tgpineapple: It does a lot of things that’ll be too difficult to explain in a single post because you need to pull in a lot of information from biology to understand it, but I can try.
Ionising radiation is the dangerous kind because it has the power to cause molecules to break up. When a molecule breaks up, it goes from a stable form to an unstable form. This unstable form can attack other molecular bonds, causing damage. The most significant damage in our body from ionising radiation at the beginning is because of Reactive Species (also known as Reactive Oxygen Species but there are other types like Reactive Nitrogen Species or Metals) which are highly reactive and cause a lot of local damage by attacking cellular components that are nearby.
When this happens you get one of two things. Either the cell recognises that its too far gone and kills itself (apoptosis). Or, the cell doesn’t, and it starts to break apart (necrosis). This is pretty bad. In addition to the cells literally being torn apart (kind of like blending fruits), they also release special molecules (mediators) triggering something called inflammation which can have nasty effects. While it usually helps the body, because your cells are all torn up, you get stuff like bleeding, swelling, fluid in places where you don’t usually get it, etc. This is acute radiation damage. You basically give the person an analgesic (painkiller) and hope they survive. We can supply blood and stuff, but the rest of it depends on how strong a person is.
The major effects depend on where the cell damage happens. In your bones, you produce less red blood cells, less white blood cells because they normally produce these, so damage = less production. In your intestines, you can cause a lot of bleeding because your intestines have a lot of small vessels to assist absorption of nutrients. On your skin, it starts swelling, bleeding, forming ulcers, and shedding. All of these happen from the same basic principle, its just cells getting shredded and our body trying to help but really messing up and making it worse.
The body’s also really weakened because of this, and your white blood cell factors can be damaged because of the radiation. We can give antibiotics which help stave off secondary infection while the body tries to heal.
And the rest of it:
The worse part is DNA mutation. Your cells can usually repair DNA mutation because we have special enzymes that do it. However, this can go wrong. When a gene mutation happens, it can be lethal, causing the cell to kill itself, apoptosis, or stop functioning which also causes it to kill itself. When it’s non-lethal, the cell has to catch the mutated gene and repair it. If it can’t do it, the cell passes it on.
Okay, mutations aren’t too bad when you have one. They might have minor effects like the cell not doing the same thing anymore, or they don’t recognise other signals that tell it to kill itself, or it might grow really fast, or it might not know when to stop growing. The body can catch cells that do this and kill them, but sometimes they miss them. What’s worse, is when they get more than one of these mutations. Suddenly, the cell doesn’t respond to other cells telling them to die, and they can hijack cells around them to support themselves (desmoplasia). Even worse, is that they grow fast, they don’t know when to stop and that’s called cancer. The more of these non-lethal mutations they have, the worse they get, becoming these unrecognisable messes of cells that look nothing like the normal cell and they’re very scary because they’re like unkillable, super dividing, parasitising super-cells.
How do we stop cancer. Well, we could target these cells specifically, but how? They’re basically the same as other cells, except they don’t really respond properly. One thing we can try is looking for them using X-ray and CTs and such, and finding areas that are strangely dense or lumpy. Then, we use radiation to blast them, hoping that acute radiation damage like I mentioned earlier will kill them before it kills us. Alternatively, we dump a bunch of poison in our body, hoping that those cells die first before our body does.
Cancer cells use up more energy and nutrients than other cells do. The hope is that they suck in more poison as well, and that’ll kill them first. But this also causes havok on the rest of the body. We don’t know how to target them just yet, because each cancer is different. A different gene mutation can give the same cancer in different people, or even in the same cell.
I had to shorten a lot because it is _insanely_ complex.
kodack10: There are two types of radiation poisoning, and which is which, affects your options for living.
If you are exposed to ionizing radiation, say from an Xray machine, or solar flare, or exposure to hard radiation (without being exposed to the chemicals themselves) then it’s like your body got an inside out sun tan. The radiation shoots through your cells like a cosmic machine gun, damaging your DNA, RNA, and basically damaging large amounts of cells at once similar to a flame.
The good news is that all a person needs to do is get away from the source of the radiation, and new damage stops immediately. Just like pulling your hand out of a flame stops you from being further burned.
The immediate result of this is that the dead or dying cells begin to release toxins into the blood and muscles, the body tissues begin to swell similar to being burned by a fire, and there is trauma to the exposed parts of the body. How much exposure determines how quickly these symptoms set in. Usually from hours to days, although nausea can occur within minutes.
The longer term problem is that with the genetic code of your body damaged in so many places, the cells can’t reproduce properly, much like a computer program that’s been corrupted. This leads to secondary cell deaths, mutations, cancers, and all kinds of nasty secondary effects. If you survive the initial dose of radiation, these secondary effects will plague you the rest of your life.
So that is assuming you were exposed to radiation, but not exposed to radioactive elements directly. IE you’re exposed to the light, not the light bulb itself. If a person comes in contact with radioactive elements, fallout, nuclear waste, etc, then these sources of radiation get on their skin, in their hair, in their clothes, inhaled in their lungs, ingested in their saliva, and once in the body, they continue releasing that damaging radiation until either they radioactively decay (a very long time), they are cleaned out of the body through something like chelation (not very effective), or the person dies.
There are some treatments that can help if administered early enough after exposure. For instance one of the more dangerous elements in nuclear fallout is radioactive iodine, which tends to concentrate in the thyroid. However if you dose somebody up with a large amount of regular iodine, then the thyroid becomes saturated and can’t take any more in, effectively rejecting the radioactive iodine.
This is the far more dangerous kind of radiation poisoning because you can’t remove the person from the source of radiation, since it’s inside of their bodies. In other words even if they are moved away from the source of contamination, they themselves are contaminated, and will continue to receive radiation. The paper suits and dust masks that people wear in contaminated areas, do not protect them from radiation at all, but they do provide protection from contamination by radioactive dust by covering their faces and clothing.
Now naturally a normal medical xray isn’t giving you burns or cancer because it’s relatively weak. So we have a measurement system that takes into account actual damage, and risk of damage to your body and we call these Sieverts. It’s not a measurement of radiation itself, but is instead a measure of how much damage that radiation would cause to a person. At low levels it increases the risk of cancer. At high levels it results in cell death.
BeautyAndGlamour: If the dose is high enough (~2 Gy), the radiation kill your very sensitive blood stem cells. Your white cell count will diminish and you will have a reduced immune system. If left untreated it’s likely to kill you within a few months.
If the dose is higher (~4 Gy) your intestines are in danger, and the colon stem cells might die. If this happens your villi in the gut do not regenerate, and are eventually grinded down completely within a few weeks. This leads to open wounds in the colon, and infections, which might kill you, even if you’re hospitalized. Your blood stem cells will of course die too, but the gastrointestinal syndrome will kill you first.
At super high doses (~ 100 Gy) vessels rupture in the brain and the pressure will kill you within a few days. Little is understood about this case. You are guaranteed to die.
So treatment is basically just to keep the body alive and hope that it manages to regenerate new stem cells e.g. through transplants. And these are all the syndromes associated with a whole-body dose. For medical radiation cases, the dose is localized. In that case a too high dose will cause the skin to die (necrosis) which if left untreated will lead to nasty infections and death. Skin grafts have been used to save patients whose been accidentally over-exposed.
brazzy42: Radiation poisoning is basically random damage to cells throughout your body, for more details see [this comment of mine](https://www.reddit.com/r/explainlikeimfive/comments/5yry50/eli5why_do_you_get_better_for_a_few_days_after/deshgyw/).
Medicine cannot really cure any of that. It can treat some of the symptoms (like dehydration from vomiting) and prevent those from killing you while your body repairs itself, and it can support some of the body’s repair efforts, for example the bone marrow (which is responsible for producing blood cells) can be severely affected, and there is a protein that stimulates bone marrow growth. While it works, blood transfusions can supply the blood cells your body isn’t producing.
In cases where the radiation poisoning comes from *contamination*, i.e. radioactive material got into your body and is *still* releasing radiation that constantly damages your body, medicine can play a very important role in saving your life by removing some of that radioactive material. For example, giving you lots of non-radioactive iodine can prevent your body from holding onto radioactive iodine, and some substances form bonds with certain radioactive elements and cause your body to excrete them.
But if the radiation poisoning is too severe, you will die and the only thing medicine can do is to ease your suffering.
mitch_der: Radiation cause mutations in our DNA. Basically, it’s because they are high-energy photons and colliding with the DNA molecule they give this energy to the atomic bonds, breaking them or changing them. So maybe a base will be missing or it will be changed.
This mutation leads to diseases such as tumors, or (if it affects gonads) it will show in children (and this is why radiation is dangerous not only for an individual, but also for their descendants).
The mutation itself can’t be cured, unless you modify the DNA (but it isn’t a realistic possibility): you can only cure the results of that mutation.
stawek: Radiation damages single molecules.
Those molecules can contain oxygen, which when freed will damage another molecule cause it’s highly reactive.
Our DNA is a massive, massive molecule itself, which can also be damaged and in many places at once. Cells have the capability to repair DNA, but only to some extent.
A cell with damaged DNA either dies or passes the damage to its “children” when it divides. The latter can cause cancer, which is a long-term effect of radiation.
Cells are most affected by DNA damage when they are about to divide. Thus, the cells that divide a lot are the most vulnerable. Those are the cells producing red blood cells located in spleen (causing anaemia), white blood cells producers in bone marrow (causing a drop in immune system strength and risk of infection) and the lining of guts (causing various gastric problems, including problems absorbing nutrients and gut infections).
For comparison, nerve cells almost never divide and can take much more radiation before being affected.
When acute radiation happens the cells that are in the vulnerable stage will be damaged. There is no immediate effect because the affected cells are only precursors to the cells that do the real work. Sometime later, however, the body will experience severe lack of the cells that failed to be produced. Those types of cells die off and are regenerated constantly, so any disruption in the production of new cells leaves a shortage when old cells die.
When one knows exposure is imminent they should try covering the most vulnerable parts of their body. Experiments have shown that covering belly and a thigh bone with lead increases the survivability the most.
Medicine does not have a cure for radiation sickness. They can alleviate the symptoms and wait for the next generation of new cells to be produced and cover the deficits. If the radiation wasn’t too strong, the cells that were not dividing at the moment of exposure will remain largely unaffected and will pick up the slack. It does take very long time to recover, though, and cancer should be expected within few years.
ShitInMyCunt-2dollar: Ionising radiation basically interferes with cell function and replication. Far too info much to put into a reddit comment: