I am very confused how x rays work. How does the radiation get into the camera?
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Can you elaborate what exactly you mean ?
Unlike visible-spectrum light, the sort that human eyes and standard cameras capture, x-rays can pass through you and be captured by the camera (detector) on the other side. Because certain tissues are easier for the rays to pass through than others (i.e. bones block most rays, so it produces a “shadow” on the detector), you can draw an image from the differences.
x-rays are high frequency of electromagnetic radiation. Light is also electromagnetic radiation but at a lower frequency.
So, in principle, x-ray “photography” captures the image like how a camera takes pictures except the film used is sensitive to x-ray rather than light.
Since x-rays are a very high frequency, much of the soft tissue of humans is transparent to x-ray which allows the image to show structures like bones etc clearly. Just like how you can look through a glass bottle and see what’s inside.
Think of X-rays as very fast and tiny particles that can go through our bodies, just like how sunlight can pass through a window. When a doctor takes an X-ray picture, they use a machine called an X-ray machine.
Here’s how it works:
1. The X-ray machine has a special part called an X-ray tube. Inside the tube, there is a tiny bit of a special metal called tungsten.
2. When the X-ray machine is turned on, the tube sends out a beam of X-rays. These X-rays pass through your body.
3. Some parts of your body, like your bones, will block the X-rays and make them appear white on the X-ray picture. Other parts, like your organs or muscles, will let the X-rays pass through and appear darker on the picture.
4. The X-rays go through your body and hit a special sheet or film that can capture them. This is similar to how a camera film captures regular pictures.
5. The X-ray picture is then developed.
It’s important to know that X-rays use a very small amount of radiation to create the pictures. The radiation is carefully controlled and kept as low as possible to make sure it’s safe for you.
You know how you can see through glass? Well to an X-ray thats essentially what your body is, glass, and it can see straight through.
Bone on the other hand, is denser so it can’t see through, so would be like a normal opaque object to us, so that’s how it sees bone.
You know – you can do it with light too!
Take a strong light bulb. Now place it like this:
Light bulb | transparent plastic sheet. |. a cup. | wall
You’ll see the shadow of the cup on the wall, but no shadow for plastic sheet, right?
Replace light bulb with source of X rays
Plastic sheet is muscles – they don’t ‘block’ x rays just like the plastic sheet doesn’t block light as it’s transparent
Cup is bones – bones block x rays
X ray you see at doc office is like the wall – it shows the shadow
Imagine a shadow-puppet show.
In the far back there is a light source shining brightly, then there is a kind of “stage area” where the puppets move around (in between the light and the screen), and finally there is a screen which is bright everywhere except for where the puppets and other props blocked the light and made a shadow.
We’re not actually seeing the puppets themselves, just their shadows on the screen.
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X-rays work in very much the same way.
In the far back there is an x-ray source shining brightly, then there is a “staging area” where the patient stands, and finally there is a screen (which used to just be a very large square of special Xray-sensitive film).
So, when an X-ray technician “takes an X-ray” what they are essentially doing is clicking the camera so that a short bright flash of X-rays happens; that bright flash then hits the patient and gets blocked by their bones which ends up making bone-shadows at the screen area; the film at the screen area then absorbs the X-ray flash and turns black if there was light there or stays white if it was in a shadow.
So, we’re not actually seeing pictures of ‘white bones’ when we look at an X-ray, what we are seeing is a black-and white image of the shadows of bones (as a film negative).
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Also, nowadays there are multiple ways to engineer reusable/digital detectors (like digital cameras) rather than literal old-school sheets of film.
And also, bones aren’t the *only* things that block X-rays, they are just really good X-ray blocking/absorbing materials. Our meaty watery fleshy bits can also block *some* X-rays but they are mostly clear… kinda analogous to how if you had a shadow-puppet hold a water bottle you could maybe see how full/empty the bottle it is based on how much light comes through in the shadow.
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