La audiencia pública del FDA en la radiación médica calienta para arriba

por Brendon Nafziger, DOTmed News Associate Editor | March 31, 2010
Differences over the
value of CT colonography
The American College of Radiology says "political elements" crept into a public U.S. Food and Drug Administration meeting on Tuesday, set up to discuss ways to protect patients and practitioners from the dangers of medical radiation.

At the hearing, an ex-FDA staffer alleged that the agency axed him when he objected to approving a CT scanner for colon cancer screening.

The staffer, Dr. Julian Nicholas, a gastroenterologist now at Scripps Clinic Rancho Bernardo in San Diego, accuses the federal agency of punishing him for fighting pressure from above to approve the device.

Dr. Nicholas believes so-called virtual colonoscopies expose patients to unnecessarily high doses of radiation. If widely adopted, they would lead to cancer deaths, he says.

Tuesday's session of the public meeting, which runs from March 30-31 in Gaithersburg, Md., focused on CT scans and fluoroscopy. Wednesday's hearing is set to look at user education and quality assurance.

The American College of Radiology, which supports virtual colonoscopies, believes Dr. Nicholas has not "looked carefully at the literature" on the subject, in the words of E. Stephen Amis, M.D., chair of the ACR's Task Force on Radiation Dose.

"Dr. Nicholas is a gastroenterologist, and gastroenterologists are always going to push optical over CT colonography," Amis tells DOTmed News.

It's understandable that physicians endorse their own specialties' approach to screening. But this may result in professional contention between radiologists who favor imaging, and gastroenterologists who prefer screening with colonoscopy.

Last year, Medicare refused to reimburse CT colonography screenings, claiming the evidence for it was mixed. But it does have backers in other corners: the American Cancer Society supports the procedure, as they think it can encourage more people to get the checked, and thus help prevent some of the nearly 50,000 deaths from colorectal cancer in the U.S. each year.

Currently, only 20-30 percent of adults over 50 advised to go for colonoscopy screenings actually attend; the rest put off by the discomfort of the procedure or worries over sedation, according to Dr. Amis.

Dr. Amis also calls the specter of a public health concern with CT colonography "nonsense," saying that it's a safe procedure in the right hands, delivering 5 mSv of radiation. That's about half of a typical abdominal CT scan, though nearly 50 times the dose of a chest X-ray, and equivalent to about two years of natural background radiation.

In a highly publicized move, President Obama underwent a virtual colonoscopy in early March. "His doctors must know what's going on and wanted to do the right thing," Dr. Amis observes.

Still, Dr. Amis believes the imbroglio over Dr. Nicholas' firing distracted from what the meeting was about: finding ways to improve safety for practitioners and patients exposed to medical radiation. Along these lines, the ACR supports setting up a national registry for radiation dosages to allow doctors' offices to benchmark their performance.

"You could then tell a practice, 'You guys are operating well outside the parameters. You need to look at what you're doing,'" Dr. Amis says.

Image Gently

Members of the Image Gently steering committee also attended the meeting, hoping to find ways to protect pediatric patients from medical radiation. Children are at greater risk from medical radiation because it takes time for deadly cancers to develop from the exposure.

"One size doesn't fit all," Dr. Amis says of determining the right procedure for patients.