Straight, No Chaser: X-Ray Basics

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“C’mon, Doc. I just want to be sure!” If I’ve heard it once, I’ve heard it a million times. You love x-rays. They’re cool, and they sometimes tell you what’s wrong. How much do you know about them? What should you know about the different types of tests done? What about the risks? This Straight, No Chaser explores the how and why of different radiologic studies.

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How do x-rays work?
X-rays are forms of radiant energy that pass through the part of the body being examined. While doing so, a special film or monitor allows a radiologist to view pictures of internal structures.

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What are x-rays used for?
X-rays have other uses than determining whether you have broken bones. There are many other uses, including the following:

  • Chest x-rays help in evaluating punctured lungs, the presence of pneumonia or lung masses (e.g. abscesses or cancer), heart size, shape and abnormal content (e.g. calcium deposits).
  • Abdominal x-rays help identify punctures of various organs, the presence of blocked intestines (bowel obstructions), hernias, constipation and many other conditions.
  • X-rays also identify bones that have been dislocated (moved from the normal location in a joint) or suffer from arthritis or infection, and they can often detect foreign objects. X-rays can confirm the placement of tubes your physician has placed (e.g. breathing tubes, tubes through the nose or penis or special IV tubes) and facilitate certain medical procedures.

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I’ve heard CT scans are just fancy x-rays. Is this true?

That’s overly simplistic but not entirely inaccurate. CT scans do involve the passage of a fan-shaped beam around the area in question, produce higher quality images than regular x-rays. This also involves more radiation.

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What is fluoroscopy?
An easy way to understand radiology is to call it “screening.” In this example, the x-ray beams are being viewed in real-time via a moving picture on a TV screen. This type of study can be especially important for the identification and removal of foreign objects in the skin or for looking at the stomach and intestine.

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Are ultrasounds and MRIs also x-rays?
No. Although x-rays are used as a generic term by many in the lay population, these procedures are different and would be better called radiologic or medical imaging studies. Ultrasounds and MRIs (magnetic resonance imaging) don’t use x-rays, so they are safer. Many are familiar with the use of ultrasounds in pregnancy, but they are helpful in many situations, including trauma, identification of gallstones, the presence of abscesses and many other scenarios. MRIs growing in popularity because of its superiority in identification of many conditions, particularly neurologic concerns. However, it’s limited availability is a problem.

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What about nuclear medicine studies?
In this type of study, radioactive materials called isotopes are injected into a vein, swallowed or inhaled. These isotopes concentrate in a specific area (body organ or tissue) when the emissions (known as gamma rays) are detected by a special camera. These emissions present a picture of the affected area.

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What else do I need to know? Why is my doctor always refusing to order x-rays?
In the hands of a good physician, these tests confirm diagnoses, not make them. In many instances, a good examination eliminates the need for x-rays. An example of this concept has been previously discussed in a Straight, No Chaser post on ankle x-rays. Also remember that for injuries, x-rays look at bones. Your muscle spasm, ligament and tendon injuries won’t show up on an x-ray, so it’s a waste of time and money to do the test.
The rest of the story is about safety. These x-rays, gamma rays and radioactive isotopes bring risk. Although they won’t turn you into the Incredible Hulk, your physician is considering your lifetime exposure and risk. Avoiding unnecessary x-rays is a key part of that. This risk will be discussed in greater detail in another post.
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