X-rays Explained

How an X-ray Can Be Used To Provide Healthcare

man coughing, coughing after surgery, coughing post operatively
A Chest X-ray Can Help Diagnose a Cough. Credit: Getty Images/George Doyle

Radiography, commonly known as an X-ray, is a test that provides a flat image of the internal structures of the body. The test is non-invasive, meaning that nothing is inserted into the body to obtain the test results. In fact, the patient cannot feel an X-ray being performed.

How Does an X-ray work?

An X-ray uses electromagnetic radiation to produce an image of the body.  Photographic film is placed behind the area of the body that is going to be X-rayed, with the source of the radiation in front of the part.

 X-rays pass easily through soft tissue, such as skin. Bone allows little to no radiation to pass through.  The differences in the densities of these tissues produce a black and white image, with bones showing up as white and other tissues showing up in a variety of grey and black tones. 

Why is an X-ray Done?

An X-ray is done to examine the inside of the human body without surgery.  It can be used to look at bone, or some soft tissues to determine the nature of an illness or injury.

Common Reasons for an X-ray

X-rays are frequently used to diagnose the cause of a serious cough and other types of lung problems, some types of serious heart disease that change the size of the heart, and to examine broken and dislocated bones.  

X-rays can also be performed to insure that a problem has been corrected.  For example, a child who fell may have an X-ray to determine that their arm is broken, then another X-ray after the arm has been set to make sure the bones have aligned properly.

 If the bones are in the correct place, a cast can be placed on the arm. 

Radiology Technicians

Radiology technicians are responsible for obtaining X-rays.  They position the patient for the best images of the area, they determine the right "exposure" for the film, and they produce the images for the physician to review.

 

Radiologist

A radiologist is a physician who has trained to read X-rays as well as other types of imaging tests.  While many healthcare providers are able to read X-rays themselves, most facilities have a radiologist read every X-ray performed to make sure that nothing is missed in the process.  Once the radiologist has "read" the X-ray, a document is created describing the findings and any diagnosis that is able to be made from the images.  The radiologist may also recommend additional imagine studies, such as a CT scan or MRI, if necessary.

Risks of X-rays

An X-ray exposes the patient to a small amount of radiation.  For this reason an X-ray should only be performed when necessary as radiation is known to cause cancer.  

Pregnant women should only have an X-ray when necessary, and when necessary, the fetus should be shielded from the radiation with a lead apron. This is to prevent any potential birth defects from the exposure to radiation. 

Limitations of X-rays

An X-ray is quite good at identifying broken bones and diseased teeth, but is less helpful with diagnosing soft tissue problems or problems with a solid organ like the kidneys and liver.

 An X-ray can show a broken leg, or pieces of a bullet inside a wound, but does not show a bladder infection or an inflamed appendix.  An X-ray is of little value for examining the brain, as the skull prevents images from being produced, instead these images show the facial bones.  

For soft tissue problems, a CT scan or an MRI is often of more benefit. 

Source:

Medical X-ray Imaging.  Federal Drug Administration.  Accessed November, 2015. http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm175028.htm

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