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