A study published in the Archives of Internal Medicine two years ago concluded that as many as 29,000 cancers a year could be caused by the radiation from diagnostic imaging, and as many as 15,000 people actually die from cancers caused by it.

“Our minds have been marinated to believe more is better,” said Rosemary Gibson, an author of books on medical overuse and a section editor with the journal that published the study who spoke about the dangers of overutilization during a session on the last day of the American College of Healthcare Executives' annual Congress on Healthcare Leadership in Chicago.

“In many contexts, the mantra is volume, volume, volume. That certainly can drive overuse,” she said, highlighting a 2008 statement from the National Priorities Partnership that named four prime areas of medical overuse: medications such as antibiotics, C-sections, laboratory testing and diagnostic procedures.

One hospital executive in the audience Thursday morning recounted the story of how her husband, following a surgical procedure to remove his cancerous bladder and build a neobladder out of his intestinal tissue, was put on a regular regimen of CT scans.

But in addition to giving him all that added radiation, the testing resulted in two consecutive—and traumatic—false positives for continued presence of his cancer because the testing was detecting abnormalities in the new cells given off by his neobladder.

“We just said, we're not doing this anymore,” said the woman, who requested her name not be published.

The conventional wisdom had been that financial incentives and fear of malpractice drive medical overuse, but Gibson said a more detailed review finds other causes as well, including fear of uncertainty, misplaced enthusiasm by physicians, peer pressure among doctors and patients' expectations.

“Overuse has an impact on our health and well-being,” Gibson said. “We're reaching a point of critical mass where we realize this truly is a public health hazard.”