Health News Review

In case you missed them, many stories reported on a new analysis of the explosion in the use of CT, MRI and other advanced imaging methods.

The Los Angeles Times: “Use of imaging tests soars, raising questions on radiation risk.”

Researchers looked at “data from patients enrolled in six large health maintenance organizations,” and “found that doctors ordered CT scans at a rate of 149 tests per 1,000 patients in 2010, nearly triple the rate of 52 scans per 1,000 patients in 1996.” Meanwhile, “MRI use nearly quadrupled during the period, jumping from 17 to 65 tests per 1,000 patients.”

The New York Times: “Radiation Concerns Rise With Patients’ Exposure.”

 “The study, published in the Journal of the American Medical Association, says that while advanced medical imaging has undoubted benefits, allowing problems to be diagnosed earlier and more accurately, its value needs to be weighed against potential harms, which include a small cancer risk from the radiation.”

WebMD: “CT Scan Rates Tripled at HMOs in the Last 15 Years, Doubling Radiation Exposure to Patients”


The average radiation dose from a chest CT scan is 7 millisieverts, compared with 0.1 millisieverts for a typical chest X-ray, according to the American College of Radiology. But those levels can vary widely by machine, with some low-dose scanners delivering as little as 1.5 millisieverts for a chest CT, and some older machines delivering far higher doses.

Researchers say a radiation dose of 50 millisieverts starts to raise concerns about human health, and a dose of 100 millisieverts is thought to raise the risk of cancer.

MedPage Today: “Expanding indications, patient and physician demand, medical uncertainty, and defensive medicine likely all contributed to those trends.”


Greg Pawelski posted on June 13, 2012 at 1:11 pm

There was a large collaborative trial in 2006, with CMS and ACRIN to gather data shared with CMS gleaned from the National Oncologic PET Registry (NOPR), what was thought to determine efficacy of the PET scan in cancer treatment management. The results of that study showed that 36.5% of patients anticipated course of treatment was changed. Some thought that this was significant.

This was not efficacy. Efficacy means that the use of the modality in question (lab test, radiographic test, whatever) improves clinical outcomes, compared to patient management in the absence of such testing. All the CMS/ACRIN data showed is that the doctors pay attention to the test results (and it looks like they paid attention!).

The “bar” is very low for PET because it benefits clinical researchers (e.g. ASCO leadership) and is a convenience to doctors (who only have to write an order) and makes a lot of money for institutions which provide it. It’s never been shown that the use of PET results in patients live longer. The use of PET, in most cases, has negligible impact on ultimate clinical outcomes.

Efficacy doesn’t mean proof that treatment decisions are changed; efficacy means that you prove that patient “outcomes” are improved as a result of the changed treatment decisions. It hasn’t been proven to improve outcomes and that is what is meant by “efficacy” in this context.