More paediatric scans done as faster (~1s) scans now so less need for sedation.
Average background radiation = 2.5-3mSv/yr (~25-30 CXRs)
Typical scan doses
Approx Ave Dose (mSv)
Chest X-ray Equivalent Dose
~Equivalent Period of Background Radiation
Pelvis or Abdomen
CT angiogram of aorta
Trauma pan scan
Reducing radiation dose
Is X-ray/CT really necessary
Is there an alternative modality e.g. USS/MRI
Focus scanning only on area of interest
Adjust CT parameters (tube current and pitch) for body type & organ
CT scans can be performed with lower exposure in children, if employed.
Use of newer software that improves quality of low dose scan results
Estimated lifetime cancer mortality risk attributable to a dose similar to an abdo CT: 1.1. 1yo child: ~0.05% (head) & 0.1% (abdominal), reducing to <0.01% & 0.02% in adults>35y. Overall ~1:1,000-1:10,000 CTs result in a cancer death.
Risk F>M generally, sig (1.5-2.5x) if radiation of chest(breast) at all ages, or head <35y
Additional risk is still low (1%) compared to background risk. (Lifetime risk of cancer in Aus ~25-33%, and lifetime cancer mortality ~10-15%).
Survivors of atomic bombings @ Hiroshima and Nagasaki were exposed to ave 40mSv.