Radiobiology > Background > Typical Patient Doses

Patient Exposures from Medical Imaging

Because of the uncertainties in establishing risk-benefit ratios for diagnostic radiation exposure, the International Commission on Radiological Protection has concluded: “radiological examination shall be carried out only if it is likely that the information obtained will be useful for the management of the patient or for improving the health status of the population.”

Single plain chest radiograph  

  • effective dose is approximately 0.02 mSv, which corresponds to 3 days of equivalent background radiation

Small bowel follow-through  

  • has an effective dose of 3 mSV, equivalent to about 150 chest films or 16 months of background radiation exposure
Single CT of the abdomen or pelvis 
  • is approximately 10 mSV, equivalent to 500 chest xrays or 4.5 years of background radiation

For more dose estimates, see Radiographics; 1999: 19:1289-1302.

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