Eli5 How does radiation therapy actually work? Like how doesnt it break down more of the body and make the cancer worse or something like that? And does it target only cancer area or everything?
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So I actually just read a study of the Therac-25 situation (google it, software bug caused radiotherapy machine to give people harmful/lethal doses.
But… along with that I got some education on nuclear medicine.
So “radiation” is essentially pieces of an atoms nucleus that go flying off from the atom at very high energies/speeds. There’s also gamma radiation which is energy, but that’s mostly not in play here… those little pieces of nucleus, mostly I believe protons in regard to radio therapy, crash into molecules in your body (dna, for example), disrupt their structure and cause damage. This kills normal cells and cancer cells alike.
So, just focusing on the proton for brevity’s sake.. a proton at a certain energy level will have a certain amount of penetration. This means they know how much energy they’re putting into the machine, so they can position you and/or the machine in such a way that they’ll know where the protons (radiation) is likely to stop, where it’ll end up.
It turns out that in particle physics, while a particle will lose some energy along its whole path, it will deposit the vast majority of its energy at its stopping point. Which is super interesting, I never knew that.
So, knowing how much the proton beam will penetrate, they can set things up to control where the beam will end up… and while it’ll have some effect on the cells in the path, it’ll mostly just be dumping it’s energy into where they want it. Which (hopefully) will destroy the cells there and have minimal impact on anything else!
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