Coronary CTA and the four fingers of fault

February 11, 2009

A survey of clinical sites in Europe and the U.S. published last week in the Journal of the American Medical Association found that patients undergoing coronary CT angiography receive a median radiation dose equivalent to 600 chest x-rays. Some places belt patients in a single CCTA with as much dose as they would get from 1500 chest radiographs.

A survey of clinical sites in Europe and the U.S. published last week in the Journal of the American Medical Association found that patients undergoing coronary CT angiography receive a median radiation dose equivalent to 600 chest x-rays. Some places belt patients in a single CCTA with as much dose as they would get from 1500 chest radiographs.

What makes this all the more mind-boggling is that the technology to cut this dose by two-thirds or more is readily available. GE, Philips, Siemens, and Toshiba all have their own means for doing so, and they have been selling these products for about two years.

In a blame-oriented society such as ours, it would be natural to ask who is responsible for this? Before doing so, however, we should ask why are some of the most technologically advanced places in the world irradiating patients so irresponsibly?

The answer applies not just to high technology but to any technology: highways and bridges, automobiles, and gas grills. Simply put, it's more exciting to build something new than to maintain or enhance it. In this regard, CCTA has it tougher than most.

Aging highways and bridges crack; gunked-up gas grills burn unevenly; untuned engines fail to turn over on cold winter mornings. CTs, on the other hand, produce excellent images of the coronaries whether they are tweaked to cut dose or not. And there is the rub, when it comes to assigning blame. Pretty much anyone pointing a finger should consider the three-finger rule: for every finger pointing at someone, three are pointing at you. Honestly, there's more than enough blame for everybody.

Vendors have developed the technology for reducing dose, but have they pushed these technologies as hard as they could? Physician groups focus on appropriateness criteria, but are they making enough of an issue about the dose given to those who do undergo these exams? Medical physicists, rad techs, administrators, and radiologists are intimately familiar with the dangers of x-radiation, yet are they aggressively seeking ways to minimize them?

Some will say that education is needed. But along with education must come the motivation to act. A survey finding that sites do not use dose reduction techniques is a good start. Now we must find out what it will take to get sites to use them.

The marketing of these technologies so far has not been enough. And the clock is ticking on how long we have to figure out a new approach.

The JAMA study should be a wake-up call. It has documented the need to reduce CCTA dose. If the imaging community does not act, regulators will.

And when the government gets into the blame game, it points more than a finger.