Types of Medical Imaging
One of the things patients may undergo is have some kind of “imaging” done on their bodies. These imaging tools help doctors scrutinize details of the ailing part of the body that are not visible to the naked eye, and pinpoint very specific areas of disease and treatment.
Wilhelm Röntgen discovered the X-ray in November 1895. Röntgen, a physicist, introduced “radiographs” in January 1896 at the 50-year anniversary meeting of the Society of Physics. A few weeks later, a medical journal acknowledged the clinical potential of “radiographs” when it published an article of a “radiograph showing a glass splinter lodged in the finger of a 4-year-old. The commercialization and mass production of X-ray tubes spread this technology around the globe, and within a few years radiography was recognized as a great medical advance.”1
Today, medical imaging comes in various forms and power. Below are brief descriptions of these imaging tools to help patients understand their importance, utility, advantages and disadvantages.
The X-ray as an imaging device shows images of bones, some tumors and other dense matter.
1. Quick, painless, and non-invasive
2. Helps diagnose broken bones, some cancers and infections
Very small risk of cancer in the future—especially for children—from exposure to ionising radiation (X-rays).
Computed Tomography (CT Scan)
The CT Scan has the ability to show detailed images inside the body, including bones, organs, tissues, and tumors.
1. Quick and painless
2. Helps diagnose more diseases than plain X-ray
3. Helps pinpoint or exclude the presence of more serious problems
4. Helps verify the recurrence of a previously treated disease
1. Small increased risk of cancer in the future—especially to children—due to exposure to higher doses of ionising radiation (X-rays)
2. May need to inject patient with a contrast medium (dye), which causes kidney problems or allergic or injection-site reactions in some people
4. May require anesthesia
Magnetic Resonance Imaging (MRI)
The MRI uses magnetic fields and radio waves to show detailed images of organs, soft tissues, bones, ligaments and cartilage.
1. Usually painless and non-invasive
2. Uses no ionising radiation
3. Helps diagnose a wide range of conditions
4. Helps provide similar information to CT Scan in some cases
1. Can be lengthy and noisy
2. Slight movements can ruin the image, requiring a re-test
3. Can make some people feel claustrophobic
4. Requires the patient to be very still, and so may need to sedate or anesthesize those who can’t stay still—particularly children
5. May need to inject patient with a contrast medium (dye), which cause kidney problems or allergic or injection-site reactions in some people
6. Sometimes can’t be done on patients with special conditions such as when a heart pacemaker is present
Nuclear Medicine Imaging Including Positron-Emission Tomography (PET)
With PET imaging, the patient is injected with, inhales, or swallows a radioactive ‘tracer’. The PET scanner uses the gamma rays emitted by this material to show images of bones and organs.
1. Usually painless
2. Helps diagnose, treat, or predict the outcome for a wide range of conditions
3. Unlike most other imaging types, can show how different parts of the body are working and can detect problems much earlier
4. Can check how far a cancer has spread and how well treatment is working
1. Patient will be exposed to ionising radiation (gamma-rays)
2. The radioactive material may cause allergic or injection-site reactions in some people
3. May need to sedate patients who may feel claustrophobic
The Ultrasound is an imaging equipment that uses high-frequency sound waves to produce moving images of the inside of the body, including organs, soft tissues, bones, and an unborn baby, that are then projected onto a screen monitor.
1. Usually safe, relatively painless, and non-invasive
2. Uses no ionising radiation
3. Does not usually require injection of a contrast medium (dye)
4. Can help diagnose a range of conditions in different parts of the body, such as the abdomen, pelvis, blood vessels, breast, kidneys, muscles, bones and joints
5. Can be used to check on the health of a baby during pregnancy
1. Quality and interpretation of the image highly depends on the skill of the person doing the scan
2. Other factors can affect image quality, including the presence of air and calcified areas in the body (e.g. bones, plaques and hardened arteries), and a person’s body size
3. In some ultrasounds, patients may need to have a special probe placed in their esophagus, rectum or vagina
4. Patient may need to have special preparations before the procedure such as fasting or having a full bladder
- Imaging Explained, NPS Medicinewise; last accessed Oct. 10, 2019
- Understanding Medical Radiation, Siemens Healthineers; last accessed Oct. 10, 2019
1 The Eclectic History of Medical Imaging, Imaging Technology News; last accessed Oct. 10, 2019
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