An X-ray

Almost everyone at some point in our lives has had an X-ray. They put us in a dark room, put us in front of a cold plate and ordered us to stay still. Then they gave us the result in the form of black plastic on which we could see the inside of our body in greys and whites.

Curious, isn't it? But do we know what the process of making an X-ray is like?

An X-ray is a sheet of polyester impregnated with nitrate crystals or silver halides (silver bromide, silver chloride and silver iodide) in forms ranging from triangular to hexagonal and of very heterogeneous sizes, dispersed in a gelatinous medium. These silver compounds blacken when oxidised, i.e. when exposed to light.

The radiographic image is obtained by exposing the plate to a source of high energy radiation, commonly X-rays. X-rays are a form of electromagnetic radiation, just like visible light.

When an x-ray is done, a machine sends particles of x-rays through the body. Dense structures such as bones block most x-rays, so the film will be blank. The air lets the x-rays through and so it will look black and the muscles, fat, and fluids will look gray.

The black part we see on the x-ray will be the area that has received light around each of the initial silver atoms, due to the action of some reducing chemical that yields its electrons to the silver halides during developing.

The white part is originated by the action of chemical products that act on the zone of the radiography that has not been exposed to the light, this, on the silver halide impregnated in that zone of the radiography.

In order to obtain the definitive image, developing and fixing have to be carried out. When the radiography is developed, the halide crystals that are not part of the image are removed from the polyester film by the action of the developing water. The fixator removes silver halide crystals that have not reacted with X-rays.

The silver halides that have been altered and form the image are retained in the radiography by products such as hydroquinone, metol, etc., which cause them to oxidize and produce the reduction of silver, blackening it.

A bone x-ray is not a painful procedure.

You may experience discomfort from the low temperature in the examination room. You may also find it uncomfortable to lie still in a particular position or lie on a hard examination table, especially if you are injured. The technologist will assist you in finding the most comfortable position possible that will ensure the best quality of x-ray images.

A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your referring or primary care physician, who will share the results with you.

Some follow-up exams may be necessary. Your doctor will explain the exact reason another test is ordered. Sometimes a follow-up exam is done because a possible abnormality needs further evaluation with additional views or a special imaging technique. A follow-up exam may also be necessary so that any change in a known abnormality can be monitored over time. Follow-up exams are sometimes the best way to see if treatment is working, or if a finding remains stable or has changed over time.