Some of the tests we offer use low levels of ionizing radiation to obtain medically necessary information. Because of questions we have received from our patients, we have compiled the table below to give everyone a better idea of the radiation exposure associated with these tests, compared with other sources of radiation in our environment. As with anything else in life, your decision whether to undergo a certain test should be based not only on the potential risks, but also on the benefits of the test. We are always cognizant of the risks and only perform tests for which the benefits outweigh the risks.
Radiation exposure is measured in units called millirems (mrem) or millisieverts (mSv). The mrem number is 100 times larger than the mSv number (the rem number is therefore one-tenth of the mSv number). The table below shows "effective radiation doses" to the whole body from the tests we offer, other medical imaging tests, and our environment.
Source of Radiation
mSv
Digital mammogram (2D) [4]
0.21
Digital 3D breast tomosynthesis (2D plus 3D) [4]
0.48
Maximum allowed for a 4-view mammogram by the Mammography Quality Standards Act=12.0 mGy*conversion factor [3]
1.42
DXA testing for osteoporosis [4]
0.001
Vertebral fracture assessment (VFA) on a DXA unit [6]
0.003
Ultrasound
0
MRI
0
Breast-Specific Gamma Imaging (BSGI, 20 mCi) [5]
5.9
Lumbar spine X-ray [4]
1.4
CT scan of the chest [4]
6.1
CT scan of the abdomen and pelvis [4]
7.7
Dental X-ray [4]
0.005
Average total annual exposure in the U.S. [2]
6.20
Radon in the air we breathe in one year [1]
2.28
Radiation in the food we eat in one year [1,2]
0.40
Radiation from living in Florida for one year [2]
0.49
Radiation from living in Pittsburgh for one year [2]
0.77
Radiation from living in Denver for one year [2]
1.45
One round-trip flight between New York and Los Angeles [2]
0.05
To calculate your specific radiation exposure, two excellent sources are the Environmental Protection Agency and the American Nuclear Society. To use these charts, you should know that the elevation of downtown Pittsburgh is 1223 feet.
