An X-ray procedure allows doctors to see through human tissue to examine bones, joints, objects and, depending on the X-ray machine settings, even specific tissues, such as lungs, intestines, or arteries and veins.
What Is An X-ray?
An "X-ray" is actually a beam of light particles, or photons, invisible to the eye. When a photon has a high energy level, as in the case of X-rays, or a low energy level, as radio waves do, your eyes are no longer sensitive to the wavelength of the light.
Photons are created when electrons in orbit around an atom drop from a higher-energy-level orbital to a lower one. The excess energy in the atom caused by the electron's orbital jump is emitted as a photon whose energy is equal to the energy level between the two electron orbitals.
Photons are massless particles which may also be absorbed by an atom if the atom has an energy difference between two orbitals that matches the photon's energy. As a result of an atom's absorbing this energy, one of its electrons is elevated to a higher-energy orbital. Because an X-ray photon is a high-energy photon, it requires larger atoms with higher-energy orbitals for X-ray photon absorption.
When X-rays pass through a patient's body, bones easily absorb the X-ray photons because bones are mostly calcium, a large atom compared to most soft-tissue atoms. By adjusting the X-ray beam energy emitted from the machine, an X-ray technologist can vary which materials will be able to absorb the X-ray photons. In this way, some soft tissues can also be examined with an X-ray procedure.
By using a special film that is sensitive to X-ray photons instead of visible light photons, the X-ray captures pictures of bones in much the same way you take a snapshot. It is also possible for a doctor to examine a moving X-ray image by projecting the X-ray beam onto a fluorescent surface in a procedure called a fluoroscopy. Doctors often use this procedure to trace the path of a contrast medium through some part of the body. The contrast medium is chosen for its ability to absorb X-ray photons. The resulting moving images can be captured on video for later review, or broadcast to a video screen for live viewing.
Diagnosis
X-ray pictures are used for several types of diagnosis:
- examination of bone fractures and healing
- locating foreign objects
- detecting or diagnosing conditions, such as arthritis, osteoporosis, fluid in a joint, or cancer
- as a planning tool for orthopedic surgery
In the case of fluoroscopy, diagnoses may include:
- examination of the digestive, urinary, respiratory, and reproductive systems
- evaluation of muscles, heart, lungs, or kidneys
Your Exam
No special preparation is necessary for having an X-ray procedure, though you may be asked to remove some of your clothing or to change into a gown. You may also be asked to remove jewelry or other items that might interfere with obtaining a clear X-ray picture.
The exam begins with the technologist positioning you on the X-ray table, using pillows to help support and position the area of the body being examined. An X-ray itself causes no pain; however, if you are being examined for an injury, positioning you on the table could cause some discomfort. A lead apron placed across your pelvic area protects it from radiation (lead atoms are very good X-ray photon absorbers).
Though radiation levels in an X-ray exam are too low to pose a risk to the patient, radiation may still pose a risk to a developing fetus. If you are or could be pregnant, please inform the technologist so necessary precautions can be taken.
The technologist may also take multiple X-rays from various angles to give the radiologist and your doctor a clear view of the affected area. You will need to lie very still and refrain from breathing for a few seconds during each exposure in order to obtain a clear, well focused X-ray picture. The technologist will take the pictures from another room, but will remain in voice contact.
The exam usually only takes a few minutes, and as soon as the technologist confirms that the pictures are clear, you will be free to go. After a radiologist examines your pictures and forwards a report to your doctor, your doctor will review the X-ray results with you and confirm any diagnoses.
