Reducing Radiation Exposure in CT Guided Injections

UCSF Radiologist Dr. Hess describes new techniques to help minimize the radiation of CT imaging for back pain.

Two general approaches to using imaging

  • X-ray fluoroscopy-uses bony landmarks, assume location of relevant soft tissues
  • CT-visual and target soft tissues
  • Downside of CT-higher radiation dose to patient

Radiation Dose and CT guidance

  • We reduce dose by 80-90% just by simple changes in CT dose parameters.
  • Dose varies because different techniques are used over time. 
  • Best techniques with CT as shown is that the average dose in a lumbar spine is 3.5 mSv compared to abdominal CT which is 15 mSv
  • Background is 2.3 mSv/year


  • Back pain: a common and important problem
  • Clinical exam (and imaging) lack specificity
  • Limited role for surgery in the treatment of pain
  • Diagnostic and therapeutic roles for spine injections
  • The use of CT does not imply high radiation dose
  • CT guidance has important advantages…which so in summary you know back pain is common 


Alexander R. Margulis Distinguished Professor and Chair
Professor and Chair

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