system
Given the following post, respond as if you're commenting on Reddit:
human
Could exposure to radioactive radiation be "good"?

So I'm just curious no I'm not gonna try to expose myself to radiation and I know it's very likely to cause permanent damage or kill you but was I'm wondering is whether there is a chance when it changes your dna that it makes you "better"
gpt
Let's be clear here, ionising radiation (as opposed to non-ionizing radio waves, WiFi signals etc.) causes changes in biological specimens by changing/damaging cellular structure.

This occurs when the charged particle - an alpha particle (He2+ ion), beta particle (an energetic electron, e-) or a gamma ray (high energy photon) passes through a biological structure. 

Given that these particles are atomic sizes or smaller, and the proteins forming the DNA that is changed consist of tens or hundreds of atoms, and human DNA is literally 3.2 billion base pairs of proteins, the chances that you randomly expose DNA to radiation and it makes an improvement are about the same as randomly picking a word from the dictionary, and then randomly turning to a page of your favourite book and replacing the 57th word on that page with the one selected from the dictionary, and then making your favourite book better! And this is for the single cell affected.

For radiation to turn someone into spiderman or something requires the radiation to modify each and every relevant cell in the body in the same way. So now consider your book experiment, and imagine that EVERYBODY IN THE WORLD has to do the same with their own favourite book. Statistically impossible, right?

Now, the human body has some kind of system to guard against these changes (which happen more than you'd imagine) since we live in a naturally radioactive environment, albeit at a relatively low level. When cells are changed, some biological process switches off and the individual cell dies, and another one grows to replace it. When this doesn't happen right, people develop cancers. And this is why excessive radiation exposure kills people, because too many cells die at the same time.

Theoretically, if this process could be understood and controlled, it could lead to improvements, but not by the process of making things better, but by killing off some cells that were less efficient than the others at whatever they did, or indeed cancerous. This is the radiotherapy treatments that others have referred to.