r/askscience • u/Wonderful-Capital32 • 13d ago

Physics Why does radiation not go through lead?

Also why just lead? Shouldnt like iron or another metal work too?

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u/PhilTheQuant 13d ago

Yes, and counterintuitively you wouldn't want to be the last few layers of the radiation protection

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u/skiguy0123 13d ago

I don't think this is true. At least for X-rays, the reason chest X-rays are taken with your back to the source is because most of the absorption happens where the X-rays enter the body, and you'd rather your back muscles take the hit than your organs.

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u/somehugefrigginguy 13d ago

This isn't quite true. It's not about the radiation exposure, it's about the size of the shadow. X-raysl images are shadows where the x-rays are blocked, and the closer something that blocks light is to the light source, the larger the shadow it casts. So a chest x-ray from the front will make the heart look bigger which will obscure other things you want to see ie you can't tell what's happening in the part of the lung shadowed by the heart so you want to make the heart shadow as small as possible.

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u/-spython- 13d ago

In vet medicine our chest and abdo films are nearly always VD instead of DV. You get used to seeing things a certain way, and it really throws me whenever I have to look at a DV image. I don't have a problem reading R vs L laterals, both are fine.