Subject: Do objects that show up on X-Rays Photos Absorb or Reflect X-rays

When taking an X-Ray of something, do the things that show up on the 
x-ray, i.e. the bones, metal, etc.  Reflect the X-rays or do they 
Absorb Them, and if they absorb them, wouldn't the bone or material 
then increase in temperature, if so, is it such a minimal amount that 
it is unnoticable to the person getting X-Rayed?

Re: Do objects that show up on X-Rays Photos Absorb or Reflect X-rays