Why do x-ray machines increase cancer risk?

[DEvens]

Who knows how much X-ray radiation they were sending through our little feet?

The feet are the least affected part of the body w.r.t. radiation. It's a question of how fast cells turn over. The faster the more effect.

That's not to say it was a good idea. Radiation that can be avoided probably should be, presuming the avoidance cost (effort, risk, etc.) is small. So wearing a hat to avoid sunburn makes good sense. Taking x-rays only when medically necessary makes good sense. Refusing to attend engineering classes at university of Toronto because one of their buildings has walls tiled with uranium glazed tiles probably is not good sense.
Dan

 

[DEvens]

I hear they emit radiation which deionizes atoms. Is this due to the frequency of the x-ray? Is x-ray light considered radiation?

As others mentioned, ionizing, not de-ionizing.

X-rays can modify molecules, including DNA. Sometimes this means that exactly the change in DNA will happen that turns a cell from a normal healthy cell into a cancer cell.

There is a statistical component to this. If 1 million people get x-rays, some fraction will get cancers that would not otherwise be expected. And some will get cancers without the x-rays.

There is also a general health thing, since your immune system is capable of dealing with some cancer cells. That is part of the statistical thing. Your immune system catches some fraction. The more that there are the more likely some get by and make you sick.

There is also some controversy. One theory, the standard one, is that there is no lower limit to the dose that produces damage and increased risk. The risk is proportional to the dose, and the "no threshold" theory says this goes right down to zero.

Another theory, a controversial one, is that there is a threshold. Below that limit, the theory goes, no damage is done. The notion is sort of like getting a tan and then being resistant to getting a sunburn. But you should be aware that many people think this theory is wrong.