A Scan A Day

Medical imaging centers are popping up around the country, offering consumers whole-body scans without a doctor's referral. But as healthy people slip into scanning tubes, are they buying an ounce of prevention or a ton of trouble?

Before 72-year-old Trudy Real left on a trip to the Philippines, she wanted to make sure her heart was in good shape. Her younger brother had died of a massive heart attack at 42, and her other siblings also had cardiac trouble. While reading her local newspaper, Real noticed an advertisement for a full-body scan that could reportedly detect problems in her heart and also in her lungs, hips, and stomach. As she was in between doctors at the time, Real sneaked off to the mobile imaging trailer without telling her husband that she would be charging the $1000 procedure to their credit card.

The results she received in the mail said that her heart was as good as could be expected for a woman her age, but that a nodule in her lungs looked suspicious. When Real got back from her heart-attack-free vacation, her new doctor performed a chest x-ray and determined that she had lung cancer. "Cancer was the last thing I expected," she says. Fortunately for Real, subsequent radiation and chemotherapy obliterated the cancer before it could spread. But not everyone who steps into an imaging trailer can avert misfortune.

We live in an era of preventive medicine, says bioethicist Stephen Post of Case Western Reserve University in Cleveland, Ohio. Doctors--and their patients--have access to advanced medical imaging techniques with which they can search almost every bodily nook and cranny for signs of disease. And many biotechnology companies now offer tests for determining one's predisposition to conditions such as breast cancer and Alzheimer's disease (see "Data Rich, Information Poor"). These kinds of tools seem to bring the prospect of preventing disease within reach, but they can also threaten the elderly with unexpected costs and misinformation.

"Americans have become very frustrated with the medical system, and they are pro-technological innovation, willing and enthusiastic to embrace it," says Stanford University neuroscientist Judy Illes. Trudy Real embraced it and she got lucky. But full-scale body scanning has its dangers, and the U.S. Food and Drug Administration (FDA) cautions that their benefits are not yet known. By and large, the centers and clinics operate outside the medical mainstream: They aren't subject to government regulation and often circumvent patients' primary-care physicians. What's more, says radiologist Leonard Berlin of the Rush North Shore Medical Center in Skokie, Illinois, the products they offer are rife with pitfalls: Results that look problematic might lead to unnecessary treatment and angst. And a clean bill of health might make consumers less inclined to watch for worrisome signs.

One hundred thirty-six imaging centers peddle body scans in the United States, Illes and colleagues report in this month's issue of Radiology. Although some vendors offer magnetic resonance imaging, most push computed tomography (CT or CAT) scans--images that are essentially glorified x-rays. CT scanners take a series of x-rays along the length of the body or body part. Then, instead of an old-fashioned film catching the image, the data are fed into a computer that reconstructs the information into cross-sections or three-dimensional images. CT scans can reveal abnormalities such as a bone mass, blood clot, or shadow on the lung. The most common tests look for cancers of the uterus and lung. Some centers can also detect heart disease and the bone thinning that characterizes osteoporosis.

Currently, no one knows how often whole-body tests will catch a preventable disease. Some radiologists claim that 90% of the scans find something, but Berlin says that most of the time what they find doesn't mean anything. For example, the scans routinely pick up tissue scars that would never cause trouble if they remained undetected, says Berlin. Such false positives can lead consumers down the slippery slope of follow-up tests, which themselves can be harmful. "Sometimes you can get an injury from a biopsy," says Berlin. And because doctors don't necessarily know which abnormality will turn malignant, cancerlike lumps destined for cysthood must get treated as potential health hazards.

False negatives can also jeopardize consumers' health by lulling them into an inappropriate sense of well-being. Because some people have an adverse reaction to a dye traditionally used to detect particular malignancies, body-scanning centers don't routinely use it. As a result, says Berlin, "certain tumors will be missed, and you'll go home and think, 'Gosh, I feel great!' "

Illes's colleague, Stanford radiologist Scott Atlas, warns about radiation risks from unneeded CT scans. The FDA compares the amount of radiation received from an abdominal CT scan to that of 500 chest x-rays (see http://www.fda.gov/cdrh/ct/). However, one body-scanning center's Web site equates its scan to a typical dental x-ray. In addition, a survey in the 16 August British Medical Journal found that 97% of doctors, including some radiologists, severely underestimate the dose that patients receive in CT scans and other x-ray procedures.

In addition, Illes worries about patients requesting a scan without their doctor's approval. Only 1% of consumers ask for the results to be sent to their primary physicians. Furthermore, no regulations exist that require board certification for the radiologists running the centers, so unsuspecting patients might not know what they're getting for their CT dollar.

The direct-to-consumer advertisements that woo people to body-scanning centers "generate demand by making people nervous," says medical bioethicist Arthur Caplan of the University of Pennsylvania in Philadelphia. Illes agrees. "Open up the newspaper and [you'll] see, 'Do this before it's too late,' " she says. "And the centers all have 1-800 numbers."

Professional organizations such as the American Medical Association (AMA) need to "step up to the plate" to pressure the federal government to put advertising guidelines in place, says Illes. Although AMA doesn't endorse whole-body scanning, it has yet to establish a policy on the technology's commercialization. For worried seniors, unnecessary scans might unduly tax an already tight health care budget, particularly if patients are subsequently forced to navigate through a maze of expensive follow-up tests.

The body-scanning industry is too young to know which way advertisers might lead future consumers. For Trudy Real, the scan was worth it. "I just wanted to reassure myself," she says. But the questions surrounding the business suggest that such assurances don't necessarily mean good health.

Mary Beckman is an Idaho-based writer who buys prevention only when it goes on sale.