Answer to Question #3867 Submitted to "Ask the Experts"

Your site offers great information. I see a lot of questions about abdominal CTs, etc. However, nothing is mentioned about the urinary tract per se. I am scheduled for a spiral CT scan of the kidneys and bladder. Is there a higher radiation dosage for a spiral versus regular CT? Will this affect fertility in the future?

The important question is: Is this CT scan really necessary?  Has it been ordered by your physician?  Or is it a screening procedure you have scheduled yourself? The reason for this is that all authorities recommend that for medically justified exposures, such as CT, the potential benefit outweighs any potential risk.  If the procedure is a self-referred screening exam, that may not be the case.

As to your question about dose, the spiral scan frequently involves a larger dose than conventional technique.  Patient dose depends on the details of how the scan is conducted.  The spiral procedure may or may not involve a higher dose than a conventional scan. Measurable effects on fertility require a much larger dose than either CT technique delivers.  The only potential risk to future offspring from radiation is a genetic effect, that is, an abnormality that is conveyed to future generations.  These effects are well known in experimental animals (fruit flies, rodents, etc.) No such effects have ever been demonstrated in humans.

Conclusion:  If your CT scan is medically justified, then radiation dose is not a major concern.

S. Julian Gibbs, DDS, PhD