[Byrne]

What role does barium sulfate play in gastro-intestinal x-rays and why is it used?  I mean, isn't barium poisonous to humans?

[pantone159]

Barium sulfate is extremely insoluble. Because of that, the body doesn't absorb the barium, so the sulfate is harmless.
Othwerise, barium is indeed very poisonous.

My guess is that the high atomic number/weight of barium makes it show up well on x-rays.

[Byrne]

Barium sulfate is extremely insoluble. Because of that, the body doesn't absorb the barium, so the sulfate is harmless.
Othwerise, barium is indeed very poisonous.

My guess is that the high atomic number/weight of barium makes it show up well on x-rays.

Interesting. Now why is it that you would want barium to show up on the x-ray anyway?

[mike]

Now why is it that you would want barium to show up on the x-ray anyway?

Usually so you can see the intestines. I don't imagine you would be able to make out all that much if you just tried to x-ray with no barium sulfate

[AWK]

Barium itself strongly absorb X-ray.