How do X-rays work?

[scilearner]

Hello everyone,

 

I really don't have any idea of how the x-rays work actually. Someone told me when light goes through that place becomes dark in the x-ray or something. Anyway if anyone can give me an explanation of how an X-ray work that would be awesome.

 

x ray----------man-------board

 

The x-ray prints on the board right. You can't see the depth in a normal x-ray right? Does everything get printed on the same plane or can you see layers. Organs that are front of others etc.

 

Also what do they mean by antero-posterior x-ray or postero-anterior x-ray? If anyone can help that would be great. Thanks a lot!!

[Cap'n Refsmmat]

X-ray film works the same way ordinary black-and-white film works, except the chemicals are probably adjusted to be more sensitive to x-ray wavelengths rather than visible wavelengths.

 

It's not that the x-rays make part of the image dark -- rather, the image you see from an x-ray is a negative. The film is developed, and it's easier to get a negative enlarged image, so they don't bother converting it to a "real" image. Negatives look cooler too.

[StrontiDog]

X-ray film works the same way ordinary black-and-white film works, except the chemicals are probably adjusted to be more sensitive to x-ray wavelengths rather than visible wavelengths.

 

It's not that the x-rays make part of the image dark -- rather, the image you see from an x-ray is a negative. The film is developed, and it's easier to get a negative enlarged image, so they don't bother converting it to a "real" image. Negatives look cooler too.

 

Actually, not in this case. The x-ray darkens the image when it interacts with the chemicals on the film, and where there's something solid attenuating the x-rays, the image is less dark. If they overexpose the film, all you get is a black image, no matter what was sitting between the source and the film. If they forget to flip the switch and develop film that never got hit by x-rays, it would be all white--or actually, opaque, no color at all exept for the medium.

 

It's not really a negative because the x-rays are not focused through a lense in any way. What we call a negative in visible photography is similar to what an x-ray image is, but it's not quite the same.

 

They are black and not black (not quite the same thing as black and white), but that's just because x-rays aren't in the spectrum we call color. When they make a print, they have the development show the clear parts as white to add contrast.

 

If you exposed color film to x-rays, it would still just turn dark. We use gamma photons for basically the same thing with industrial radiography, taking shots of welds and the like through several inches of metal.

 

Most places don't use actual film, anymore, it's all digital, now. There's a receiver that will display the image on a screen, more or less in real time.

 

Bill Wolfe

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Consecutive posts merged

 

Also what do they mean by antero-posterior x-ray or postero-anterior x-ray? If anyone can help that would be great. Thanks a lot!!

 

The first is x-rays shooting through your chest and out your back, with the film behind you. . .

 

The obverse for the other.

 

Bill Wolfe

Edited February 26, 2010 by StrontiDog