"The problem is they are almost too good," said UCLA radiologist Dr. Jonathan Goldin. "People want to take a picture of everything just in case."
Some researchers estimate that up to a third of scans could have been avoided or replaced by safer technologies, such as ultrasound or magnetic resonance imaging.
"In 20 or 30 years, the radiation debate will be like the smoking debate today," Goldin said. "People will say, 'Why did I get this imaging in the first place?' "
--
Private scanners
In the basement of a Beverly Hills office building, Dr. Hooman Madyoon peered into a computer screen displaying a pristine black-and-white image of a heart caught mid-beat.
Rotating the picture, he zoomed in on an artery and traced its gnarly path in increments of less than half a millimeter.
Through a radiation-proof window in the next room, the machine, an upright doughnut with a table positioned in the center, was being prepared for the next patient.
"It's just a matter of time before this catches on everywhere," said Madyoon, whose practice has done about 8,500 scans since installing the $1.2-million machine four years ago.
The images are created using a revolving X-ray beam that clicks on for a few seconds, scanning the human body slice-by-slice as if it were a loaf of bread.
The scans can cost from a few hundred dollars for a single organ to a few thousand dollars for a full-body image.
Since the first CT scanner in the United States was purchased in 1973 by the Mayo Clinic in Rochester, Minn., the U.S. total has grown to 24,000 machines.
That amounts to 81 CT scanners in the U.S. for every million people -- almost three times the average for the rest of the industrialized world, according to a 2007 report from the McKinsey Global Institute, an economic research group. Only Japan has a higher density of machines at 93 per million people.
About 70% of the scanners are in hospitals. But with declining prices, a growing number are being installed in private practices and imaging centers.
Today, scanner manufacturers, including Siemens and General Electric Co., tout the ease of making money with the devices. Just two scans a day can pay for a machine and its operation over a five-year period, according to a Siemens sales brochure. Ten scans a day can bring in more than $400,000 a year in profit.
