Radiation risk from medical imaging

Background

  • Around 1.5-2.0% of the cancers diagnosed annually in the United States could be related to medial imaging[1]
  • Specific subsets of patients may be at greater risk from radiation exposure, and radiation risk should be considered carefully in these patients. [2]
  • The typical lag period between radiation exposure and cancer diagnosis is 1-2 decades or longer, thus radiation exposure reduction is less important in the elderly[3]

Tests and Radiation Amounts

  • 1 millisievert (mSv) = 0.1 rad (rd) = 1 millirem (mrem)
  • 1 mSv is the dose received when exposed to 1 milligray (mG)
Procedure Radiation Dose (mSv) Additional Cancer Risk
Male Female
Comparison Doses
Yearly natural background exposure 3[4]
7-hour Airline Flight 0.02
Plain Radiograph
Chest x-ray (2-views) 0.1 1 in 197,628 1 in 147,929
Pelvis x-ray 0.6 1 in 32,960 1 in 24,655
Neck x-ray 0.2 1 in 98,912 1 in 73,964
L-spine x-ray 1.5 1 in 13,184 1 in 9,863
Extremity x-ray 0.001 1 in 20,000,000 1 in 14,285,714
Computed Tomography
CT head 2 1 in 9,887 1 in 7,397
CT neck 6 1 in 3,296 1 in 2,466
CT L-spine 5.6 1 in 3,531 1 in 2,642
CT Pulmonary Angiography 15 1 in 1,318 1 in 986
CT Abdomen, Pelvis 14 1 in 1,413 1 in 1,057
CT Chest, Abdomen, Pelvis 21 1 in 942 1 in 704

Pregnancy

  • Greatest risk of harm during organogenesis (3-8 WGA)
  • IV contrast not teratogenic (class B)
  • PO contrast not absorbed = no risk

Exposure Risk

  • <5,000 mrads = safe
  • ~10,000 mrads = small risk childhood cancer
  • ~15,000^ mrads = 6% chance intellectual disability
  • <3% chance childhood cancer

^Considered max

Always use shield when possible

See Also

External Links

External Links

References

  1. Lin EC. Radiation Risk From Medical Imaging. Mayo Clin Proc. 2010 Dec; 85(12): 1142–1146. doi: 10.4065/mcp.2010.0260
  2. Lin EC. Radiation Risk From Medical Imaging. Mayo Clin Proc. 2010 Dec; 85(12): 1142–1146. doi: 10.4065/mcp.2010.0260
  3. Lin EC. Radiation Risk From Medical Imaging. Mayo Clin Proc. 2010 Dec; 85(12): 1142–1146. doi: 10.4065/mcp.2010.0260
  4. Lin EC. Radiation Risk From Medical Imaging. Mayo Clin Proc. 2010 Dec; 85(12): 1142–1146. doi: 10.4065/mcp.2010.0260

Authors:

Ross Donaldson