Sure, but there are far more things which will kill the entire person at the same dose they’ll kill the cancer than things which can be carefully controlled by choosing the right dose.
These studies which claim to kill cancer in a petri dish usually turn out to be the former, because not killing the host is the difficult part










No, it’s not. In physics, we call the entire spectrum “light”, because it’s all fundamentally the same thing.
We can talk about “visible light”, but that’s a subset of light in general. Microwaves, radio waves, x-rays, gamma radiation, and any other section of the spectrum you can think of are all light