Radiation risk from medical imaging

Tests and Radiation Amounts

Plain Film X-ray (mrad)

Low-dose

• Head <1
• C-spine <1
• Thracic spine <1
• CXR <1
• Extrem <1

High-dose

• L-spine <1250
• Pelvis <350
• Hip <450
• IVP <900
• Urethrocyst <1500
• KUB <500

CT (1cm slices)

• Head <50
• Chest <1000
• Upper abd <3000
• Lower abd <9000

Angiography

• Cerebral <100
• Cardiac cath <500
• Aortography <100

V/Q scan <215

• (class C injectable technetium, xenon even safer)

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 CA
• ~15,000^ mrads = 6% chance mental retardation
• <3% chance childhood CA

^Considered max

Always use shield when possible

See Also

• Radiation exposure (disaster)
• Acute Radiation Syndrome