Ask Should I worry about getting a repeat CT scan in 3 weeks?

March 28, 2012

“I had a CT scan because of a kidney stone on my left side…the stone has left the kidney and it is stuck in the ureter…I also had an x-ray done …..and before the CT and x-ray I had an ultra sound… Dr. gave me a special medication and told me that in about 3 weeks to have another Ct scan done to see if the stone has dissolved. My question is should I be concern about how much radiation I am getting in such a short time?”


Thanks for your question.  Yes, you should be concerned about the amount of radiation that you receive with conventional CT scans.  In fact the federal government is also very concerned.  At present we are undertaking a large multi-institutional prospective study evaluating the efficacy of CT versus US in patients who present with acute renal colic in an emergency room setting.  This multi-million dollar study was initiated because of the potential issues of radiation damage. Of  course, CT is a very important test and is very useful.  One should be careful for over-utilization.  The younger a patient – the more potential damage can occur over their lifetime.

A reasonable alternative would be to proceed with a KUB and a renal ultrasound to rule out continued hydronephrosis.  Also, if one is trying to dissolve a stone, urinary pH can be a good test to assess if urinary alkalinization is being successful.

In our “Ask” section, we field questions from stone formers or their family members. See previous questions and answers here.

About Dr. Marshall Stoller

Marshall Stoller, MD, is a Professor of Urology at University of California at San Francisco, in San Francisco, CA
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One Response to Ask Should I worry about getting a repeat CT scan in 3 weeks?

  1. Jul says:

    I have passed 68 stones and am now taking hydrochlorthiazide to help rid my kidneys of 16 new ones. I recently had a ct scan saying I had only pieces left of the 16 stones, maybe 4,all under 3mm, which I can pass. Well, in the past month I have passed 2 stones almost 8mm each. Neither showed on the ultrasound, KUBRICK, or CT Scan.
    I read Ct scans are 95%accurate. Not sure this is true, but if it is, are the radiologist failing to give accurate result? My stones tend to have a dark and light side, are they just seeing the darker shades.

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