X-Rays

What are x-rays?

Electromagnetic radiation (EM radiation) comes in a wide range of energies. The forms that we are most familiar with are radio waves, light waves and microwaves. All energy waves travel at the same speed as light because they are the same as light except they either have more or less energy. Radiowaves are less energetic while microwaves are more energetic and can be used to heat food. The most energetic are X-rays and gamma rays which are used for imaging in the radiology departments of hospitals because they are energetic enough to penetrate through our bodies. The x-rays that penetrate all the way through turn the x-ray film black and the x-rays that are absorbed in the body (i.e. in dense bones) do not pass through and those areas on a film are left white. The result is a black and white image that represents what is in our bodies. Much the same as a hand shadow. The light shines on the wall where there is nothing in the way to absorb it. Once you put your hand in the way of the light, it is absorbed into your skin and is not able to reach the wall thus creating a shadow in the shape of your hand.

Are x-rays dangerous?

Well, yes and no. People working in the radiology field are allowed a certain amount of radiation (5rem/yr) which is considered safe. It takes 200 rem at one time to cause the first sign of radiation insult which is erythema (red skin). Erythema is equivalent to about 10,000 chest x-rays. In fact, we are exposed to radiation every day from sources other than x-rays. We are constantly surrounded by background radiation from the sun and the earth. Even potassium-40 and carbon-14 which are in our bodies and used by our cells produces internal radiation that we can do nothing about.

X-rays are an ionizing radiation which means that they have enough energy to ionize (remove an electron) from an atom. Most of the time the electron finds the atom it was bonded to and rejoins it which causes no problems whatsoever. Sometimes, however, if it is part of a molecule such as water, the ionization can cause other affects. If H2O is ionized, it can dissociate into OH* and H*. If two OH* molecules bond together the result is H2O2 better known as hydrogen peroxide. This chemical can be dangerous but only on a cellular level because the chance of this event is extremely small. Another infrequent but possible event is damage to a chromosome. If electrons are removed from the atoms in a strand of DNA it can be damaged which could result in a mutation or cell death.

On a good note, our cells have an advantage because of mitosis. Cells are able to repair themselves from most radiation damage and in more severe cases where cell death is the result, repopulation is possible. In conclusion, unless your body is inundated with a major radiation insult, your body will not even feel the effects of radiation and life will go on as normal.