X-rays are a form of electromagnetic radiation made up of waves or particles that travel through the air like light, radio signals and microwaves.
As the wavelengths of light decrease, they increase in energy. X-rays have smaller wavelengths and therefore higher energy than ultraviolet waves. We usually talk about X-rays in terms of their energy rather than wavelength. This is partially because X-rays have very small wavelengths. It is also because X-ray light tends to act more like a particle than a wave. X-ray detectors collect actual photons of X-ray light - which is very different from the radio telescopes that have large dishes designed to focus radio waves!
These x-rays are strong enough that some of them pass through objects (clothing, body tissues, and internal organs) and some are absorbed. The x-rays either expose areas on an x-ray film or are captured by a detector linked to a computer and monitor. In general, objects that are more dense, such as bones, calcium deposits, and contrast media dye, absorb more of the x-rays and do not allow as much to pass through them. These more dense objects look white while less dense objects, like air in the lungs or the liver, look gray or black. Radiologists or other experienced physicians can read these images to diagnose medical conditions or injuries.
Procedures
Medical x-rays are used in many types of examinations and procedures. Some examples include:
- x-ray radiography (to find broken bones, tumors, pneumonia, foreign objects, etc.)
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mammography (to image the internal structures of breasts)
- radiation therapy in cancer treatment
Risks/Benefits
Medical x-rays have increased the ability to detect disease or injury early enough for a medical problem to be managed, treated, or cured. When applied and performed appropriately, these procedures can improve health and may even save a person's life.
X-ray energy also has a small potential to harm living tissue. The most significant risks are:
- a small increase in the possibility that a person exposed to x-rays will develop cancer later in life
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skin burns, but only at very high levels of radiation exposure and in only very few procedures which are generally life-saving or life-prolonging
- The risk of developing cancer from radiation exposure is generally small, and it depends on at least three factors-the amount of radiation dose, the age at exposure, and the sex of the person exposed.
- The lifetime risk of cancer increases the larger the dose and the more x-ray exams a patient undergoes.
- The lifetime risk of cancer is greater for a patient who received x-rays at a younger age than for one who receives them at an older age.
- Women are at a somewhat higher lifetime risk than men for developing radiation-associated cancer after receiving the same exposures at the same ages.
Information for Patients
In most circumstances, the benefits of an x-ray or x-ray procedure recommended by your physician far outweigh the risks. You can reduce your radiation risks and contribute to your successful examination or procedure by:
- Keeping a "medical x-ray history" with the names of your radiological exams or procedures, the dates and places where you had them, and the physicians who referred you for those exams
- Making your current physicians aware of your medical x-ray history
- Asking your physician if there are alternatives to x-ray exams that would be appropriate for your medical situation
- Providing your physicians with recent x-ray images and radiology reports
- Informing radiologists or x-ray technologists in advance if you are pregnant or think you may be pregnant
Source: Center for Devices and Radiological Health
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