Tuesday, 2 April 2013

Radiography: x-ray imaging

From wiseGEEK
X-rays are part of the electromagnetic spectrum, along with microwaves and visible light. This group of waves all travel at the speed of light through a vacuum. When you have a x-ray, someone fires these high-energy waves at you. Your bone is very dense calcium, so it absorbs some of the x-ray. The x-rays that make it through are captured by a film. The black is the exposed areas, and the white of is the unexposed areas where the x-ray got absorbed by bone.

From Wikipedia
Above is a panoramic radiograph, sometimes called an OPG for orthopantomograph. I saw a couple when doing work experience at a dental practice and thought it looked quite cool. It looks like two skulls facing each other, but it's just one: the spines at the left and right of the radiograph are the left and right sides of one spine. The x-ray machine travels in a curve round your jaw to capture all your teeth. This OPG is of a nine-year-old, so you can see a lot of unerupted teeth still in the jaw.

Because x-rays are high-frequency radiation, they're ionising and can cause mutations by breaking molecular bonds in your body, which is why the rest of your body is screened while your doctor does a runner. As long as you don't have them too often, you will be fine, but doctors will have to do x-rays all the time, which is why they don't stick around.

As well as being able to cause mutations leading to cancer, x-rays are used to treat cancer in radiotherapy. Radiation damages cells' DNA, disrupting its cell cycle (the cell's life cycle of growth, DNA replication and division) and killing cells when they try to divide. Healthy cells are damaged too, but cancer cells are more affected by treatment because they divide more rapidly.

Add a touch of macabre to your wardrobe with skeleton-inspired dresses, shoes and accessories.
Left dress: Alexander McQueen

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