A Moment of Science

Exposed While Scanned

Why would people choose to have tests done that expose them to radiation?

radiation234

Photo: sixtysymbols (flickr)

An MRI scan of a brain

Imaging tests like CT scans and MRI and nuclear imaging are great tools because they allow doctors to see inside the body. But don’t they also expose people to radiation?

And if so, isn’t this a bad thing?

MRI

Yes.  And no.  Some imaging tests do expose people to radiation.  But just to be clear, MRI, which stands for magnetic resonance imaging, does not use radiation.  So if you have an MRI, there’s no risk of exposure.

CT And CAT Scans

But other types of imaging tests do use radiation.  Like nuclear imaging, which is used to look for heart disease.  And CT, or CAT scans, which use x‑rays to take 3‑D pictures inside the body.

And, unfortunately, over time these tests do sometimes expose people to dangerously high levels of radiation.  High enough to cause cancer, in some cases.

But why would doctors order tests that put people at risk for getting cancer?

Risks And Benefits

Well, mainly because the tests are often very useful.  For example, mammography is the best way to look for early signs of breast cancer.

But it’s not as clear that other tests, such as nuclear imaging, are as useful for detecting heart disease.  It may be, but there’s not enough hard evidence to be certain.

It’s not that people should always avoid these imaging tests.  But they should be aware of the risks.

  • nmrguy

    Let's get properly educated here!

    MRI does use radiation- it's radio frequency (RF) energy/radiation though! RF radiation is a form of electromagnetic (EM) radiation. This form of energy is relatively harmless compared to X-rays as used in X-ray and CT imaging. X-rays are much more energetic forms of EM radiation and can actually ionize (usually by removing an electron from) atoms and molecules- RF radiation does not. It's the ionizing radiation that is dangerous and that's why one should control the amount of X-ray exposure. Thus, the statement that, “But other types of imaging tests do use radiation. Like nuclear imaging,…” is incorrect and misleading! MRI IS nuclear imaging!

    This article does nicely illustrate the “double-edged sword” nature of technology- the risks versus benefits we must consider when taking advantage of technology (applied science)!

  • nmrguy

    Let's get properly educated here!

    MRI does use radiation- it's radio frequency (RF) energy/radiation though! RF radiation is a form of electromagnetic (EM) radiation. This form of energy is relatively harmless compared to X-rays as used in X-ray and CT imaging. X-rays are much more energetic forms of EM radiation and can actually ionize (usually by removing an electron from) atoms and molecules- RF radiation does not. It's the ionizing radiation that is dangerous and that's why one should control the amount of X-ray exposure. Thus, the statement that, “But other types of imaging tests do use radiation. Like nuclear imaging,…” is incorrect and misleading! MRI IS nuclear imaging!

    This article does nicely illustrate the “double-edged sword” nature of technology- the risks versus benefits we must consider when taking advantage of technology (applied science)!

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