Radiation Thermometer

What to know

The radiation thermometer puts common radiation doses in perspective. This resource can help people assess their own risk in the event of a radiation emergency.

A radiation thermometer scaled from negative to positive in mSv and rem

Radiation dose

Radiation dose represents the amount of radiation absorbed by the body and is measured in millisieverts (mSv) [pronounced MIH-lee SEE-vert] or rem (1 rem equals 10 mSv). The millisievert unit of measurement is used internationally while the rem is used in the United States.

Learn more about radiation dose.

Radiation thermometer

Thermometer
The purpose of the radiation thermometer is to put common radiation doses in perspective.

The thermometer uses a logarithmic scale, where each gray line represents a ten times increase or decrease in the dose, rather than a one unit increase or decrease.

Find below examples of common radiation sources and possible health effects at different doses.

Examples of common radiation sources, dose, and outcomes

100% lethality

vector image that illustrates 100% fatality rate
1000 rem / 10000 mSv

The dose that results in death for 100% of those who receive it is 1000 rem / 10000 mSv.1 People who are close to the site of a radiation emergency may be at risk for this dose.

50% lethality

vector image that illustrates 50% fatality rate
400 rem / 4000 mSv

The dose that results in death for 50% of those who receive it is 400 rem / 4000 mSv.1 People who are close to the site of a radiation emergency may be at risk for this dose.

Acute radiation syndrome and increased cancer risk

Vector images of the acute radiation syndrome typography
100 rem / 1000 mSv

The lowest dose that could cause acute radiation syndrome is 100 rem / 1000 mSv.1

Dose for which risk of getting a fatal cancer increases from about 22% (average risk of cancer in United States) to about 27% (derived from2).

Damage to blood cells

A clinician holding a blood sample.
50 rem / 500 mSv

The dose that causes damage to blood cells is 50 rem / 500 mSv.34

Relocation threshold

The recommended threshold for relocating people is 2 rem / 20 mSv.
2 rem / 20 mSv

The recommended threshold for relocating people is 2 rem / 20 mSv. If projected dose from radioactive contamination is greater for the coming year, relocate.5

CT scan

A patient lying on the table in front of a computerized tomography machine.
1 rem / 10 mSv

The dose received during a typical CT (computerized tomography) scan is 1 rem / 10 mSv.6

Average annual dose in the U.S.

Pie chart illustrating the sources of radiation exposure in the United States from naturally occurring background radiation, medical exposures, and consumer products.
310 mrem - 10 mrem

Average dose per year for people in the U.S.6 from

  • naturally occurring background radiation – 310 mrem
  • medical exposures – 300 mrem
  • consumer products – 10 mrem

Chest x-ray

Example of an upper chest x-ray
0.01 rem / 0.1 mSv

A typical dose of radiation from a chest X-ray is 0.01 rem / 0.1 mSv.6

Flight from NYC to LA

Vector image of a plane flying from New York to Los Angeles
0.0035 rem / 0.035 mSv

A typical dose from high altitude solar and cosmic radiation during a flight from New York City to Los Angeles is 0.0035 rem / 0.035 mSv (derived from7).

Dental x-ray

Dentist in an office with a patient. The dentist is point out teeth on an x-ray
0.0005 rem / 0.005 mSv

A typical dose of radiation from a dental x-ray (bitewing and full mouth survey) is 0.0005 rem / 0.005 mSv.8

Radiation dose in mSv and rem

Rem (rem)

Millisievert (mSv)

DESCRIPTOR

1000

10,000

Dose that results in death for 100% of those who receive it.(1) People who are close to the site of a radiation emergency may be at risk for this dose.

400

4,000

Dose that results in death for 50% of those who receive it.(1) People who are close to the site of a radiation emergency may be at risk for this dose.

100

1,000

Lowest dose that could cause acute radiation syndrome.(1)

Dose for which risk of getting a fatal cancer increases from about 22% (average risk of cancer in United States) to about 27%.(derived from 2)

50

500

Dose that causes damage to blood cells.(6,7)

2

20

Recommended threshold for relocating people (if projected dose from radioactive contamination is greater for the coming year, relocate).(8)

1

10

Dose received during a typical CT (Computerized Tomography) scan.(3)

0.62

6.2

Average dose per year for people in the U.S.(3) from:

  • naturally occurring background radiation – 310 mrem
  • medical exposures – 300 mrem
  • consumer products – 10 mrem

0.01

0.1

Typical dose from a chest x-ray.(3)

0.0035

0.035

Dose from high altitude solar and cosmic radiation during a flight from New York City to Los Angeles.(derived from 9)

0.0005

0.005

Typical dose from a dental x-ray (bitewing and full mouth survey).(5)

  1. CDC. Acute radiation syndrome: A fact sheet for physicians [online]. 2013.
  2. National Research Council of the National Academies, Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation. Health risks from exposure to low levels of ionizing radiation: BEIR VII, Phase 2 [online]. 2006. Available from URL: http://www.nap.edu/openbook.php?record_id=11340&page=R1
  3. Eisenbud M, Gesell T. Environmental radioactivity. 4th ed. Oxford (UK): Academic Press; 1997.
  4. Mettler F, Upton A. Medical effects of radiation. 2nd ed. Philadelphia: W.B. Saunders; 1995.
  5. U.S. Environmental Protection Agency (EPA). PAG manual: Protective action guides and planning guidance for radiological incidents (draft for interim use and public comment) [online]. 2013. Available from URL: http://www.epa.gov/sites/production/files/2015-06/documents/pag-manual-interim-public-comment-4-2-2013.pdf
  6. National Council on Radiation Protection and Measurements (NCRP). Ionizing radiation exposure of the population of the United States. NCRP 2009;160.
  7. U.S. Department of Transportation (DOT), Federal Aviation Administration Advisory Circular. Radiation exposure of air carrier crewmembers – FAA AC 120-52 [online]. 1990. Available from URL: http://www.solarstorms.org/FAAAirlines.html
  8. Gibbs SJ. Effective dose equivalent and effective dose: Comparison for common projections in oral and maxillofacial radiology. Oral Surg Oral Med Oral Path Oral Radiol Endod 2000;90(4):538-545.