Double Exposure

Double Exposure

I’ve got a hunch that generations to come will look back on our era of health care and wonder at the irony of using radiation (which causes cancer) to treat and diagnose cancer.

Of course, we couldn’t get along very well without x-rays, and there are many people who will tell you their lives were saved by radiation therapy. Nevertheless, radiation is dangerous stuff – a point I missed in a recent e-Alert. But I received a reminder in this e- mail from an HSI member named Thomas who’s also a chiropractor.

“I was very surprised at your giving any recommendation to computed tomographic colonography (CTC) without warning about the risk of causing cancer by the procedure. Tomography is an x-ray procedure and involves ionizing radiation. Please reference the article ‘Imaging X-rays Cause Cancer: A Call to Action for Caregivers and Patients.’

“Yes the OC is uncomfortable and there is a risk of perforation, but tomography is carcinogenic!”

Not to cut hairs, but the e-Alert Thomas refers to (“YouTubing” 10/17/07) didn’t recommend CTC, it simply compared the pros and cons of CTC against the pros and cons of the more traditional optical colonoscopy (OC).

But Thomas is absolutely on the right track to pose this important question: Is a high dose of radiation to detect cancer worth the increased risk of cancer?

Frightening numbers

CTC is not your standard x-ray. Far from it. In fact, a CTC scan of the abdomen produces a dose of radiation that’s several hundred times higher than the dose from a chest x-ray.

But that’s just part of the CTC problem.

The article Thomas mentions above was written by Richard C. Semelka, M.D., who is probably the leading voice in warning medical professionals about the dangers of computed tomography.

Dr. Semelka actually begins his article by praising computed tomography as a powerful tool that has “heralded a new age of medical practice based on the ability to visualize the inner working of the human body.”

But that “new age” is entering a new phase.

According to Dr. Semelka, the definitive authoritative resource on the subject of radiation risk is the 2005 report on the Biological Effects of Ionizing Radiation (BEIR VII) from the National Academy of Science. And the key fact produced by BEIR VII is this: Medical x-rays cause cancer. Dr. Semelka describes this fact as “indisputable.”

In fact, BEIR VII reveals that just one CT body scan creates a 1 in 1,000 chance that the patient will develop cancer as a direct result of the scan. Multiple scans drive the risk even higher. And most disturbing: Children given a single CT scan have a 1 in 550 chance of developing cancer, although it may take as long as two decades for the resulting cancer to be diagnosed.

The alternative

Dr. Semelka offers a four-point plan to keep patients safe:
1) Use CT judiciously
2) Reduce radiation dose whenever possible
3) Use alternative imaging modalities
4) Tell patients about risk

The alternative imaging modality that Dr. Semelka recommends is whole-body magnetic resonance imaging (MRI). In a 2005 issue of Imaging Economics, Dr. Semelka wrote a guest editorial that offered these points in arguing the superiority of MRI over CT:

  • MRI utilizes a powerful magnetic field and radiofrequency energy, but these have not been shown to cause cancer (CT utilizes ionizing radiation)
  • MRI is able to detect more lesions and is more likely to correctly characterize disease than CT
  • MRI is superior to CT in scanning the head, abdomen, and pelvis
  • MRI accuracy is extremely high in detecting diseases of the liver, brain, spine, pancreas, and kidneys
  • Further development is required for MRI to provide optimal imaging of the heart, breast, lungs, and colon, but the diagnostic level of MR imaging of these organs is currently acceptable

Currently, the cost of MRI is about 20 percent higher than CT, but Dr. Semelka notes that there are “hidden” CT costs, due to questionable findings that sometimes require unnecessary surgery and other procedures.

“Imaging X-rays Cause Cancer: A Call to Action for Caregivers and Patients” Richard C. Semelka, M.D., 2006,
“Whole-Body MRI: Why Not?” Richard C. Semelka, M.D., Imaging Economics, February 2005,