Your April 21 article Screening for cancer with CT scans risky by Dr. W. Gifford-Jones contains factual inaccuracies that require correction.
The dose of a standard two-view chest X-ray is 0.1 millisievert. The dose of a chest CT scan that would be used for lung cancer screening is 2.7mSv (or the equivalent to 27 chest X-rays), based on a recent audit of CT doses at St. Boniface General Hospital.
Newer CT scanners can cut this dose by 30 per cent to 50 per cent. The article's assertion that a chest CT scan is equivalent to 500 standard chest X-rays is clearly not based in science.
While practising medical professionals realize that Gifford-Jones writes articles more for entertainment than scientific education, I am concerned that the public could take his statements at face value and potentially base decisions about their health on them. While it is amusing to read what celebrities like Dr. Phil, Dr. Ruth and Dr. Gifford-Jones have to say, I would encourage patients to ask their local medical experts if they have questions about their health care.
Dr. Iain Kirkpatrick
University of Manitoba