How Does an X-ray Machine See Bones?
Have you ever broken a bone? If so, you have probably had an X-ray taken and have seen what your bones look like under your skin.
X-rays were discovered by accident. In 1895 Wilhelm Conrad Röntgen was experimenting with electric currents, passing them through a vacuum tube.
We don’t know what he was hoping to discover. What he did find was that while the current was going through the tube, a nearby fluorescent screen glowed. He realized that there must be an unknown ray causing the effect, so he named it X-ray, X being the symbol for something unknown. The first X-ray ever taken clearly showed the bones of his wife’s hand.
Being able to see inside the body was an enormously important discovery, and within just two months, X-rays were being used in Europe and North America to look at the skeleton and treat diseases.
X-rays are a form of radiation, which is a word for a type of energy that travels through space in the shape of waves, like light or radio. When X-rays are directed at a body, the radiation is absorbed by solid masses such as bones. Softer tissues like lungs absorb less energy. The energy passing through the body is captured on a special photographic or digital screen placed behind the body, that turns the radiation into light. Bones appear white, soft tissues appear gray, and air appears black. These pictures can clearly show doctors if a bone has been broken, or if there is something unusual in the body. If, for example, your dog has eaten your toy robot, an X-ray would show the robot sitting in the dog’s stomach.
X-rays are used for many purposes and people working with X-rays are specially trained. Radiographers understand how to operate the X-ray equipment and take care of the patient during the test or treatment.
Radiologists are doctors trained to examine and understand the images, and carry out some treatments that depend on X-rays. A radiotherapist is a doctor trained to treat diseases by using X-rays.
Doctors use X-rays to look for fractured bones, or after fixing a broken bone to make sure it is in the right position. They also use them to look for diseases like arthritis and cancer, or some types of injury. The level of radiation given during a routine test is very low, much lower than it used to be and is believed to be completely safe. The only danger X-rays might pose is to a fetus, which is a baby still growing in the womb. Women who are pregnant, or who think they might be, do not have X-rays taken unless absolutely necessary.
When X-rays are used for treatment, the dose of radiation is much higher. The rays are aimed directly at the target cells and, because solid masses absorb radiation, the high dose kills them.
It’s amazing what can result from a little experimenting!
Did you know?
Brazil nuts contain radium, a radioactive substance, and if you ate four bags of nuts, you would receive about the same amount of radiation as during a chest X-ray.