Today is my lucky day!

I mean, isn't it? It's a sunny Monday afternoon in Pikesville, Maryland, a perfect little slice of Blue America just outside Baltimore. I'm across the parking lot from a Barnes & Noble, and inside the crisp, clean offices of Virtual Physical, one of more than a hundred clinics around the country offering whole-body computed tomography (CT) scans. You've probably heard these centers hawking their services on the radio: They invite you inside for a powerful 3-D x-ray (no doctor's note necessary) that's supposed to reveal whether there are any diseases lurking beneath your epidermis.

The source of my apparent good fortune today is twofold. First, because I found Virtual Physical through its Web site, the receptionist informs me that I'm entitled to the low Internet rate of $595--a $200 savings. Better yet, it turns out that Virtual Physical has been endorsed by none other than Fred Grandy, known to some as a former Iowa congressman, known to many more (including me) as the man who played Gopher on The Love Boat. Grandy, who now hosts a radio show in nearby Washington, D.C., got a scan and nabbed an endorsement deal with Virtual Physical.

He learned that one of his coronary arteries was 30 percent blocked. Discovering this didn't prevent him from having a heart attack several months later, but, as Grandy says, he's still a "big believer" in Virtual Physical. Unfortunately, not even Gopher's approval can quell the uneasiness I'm feeling about my own scan. Here's why: Last September, a study reported in the journal Radiology estimated the amount of radiation that adults typically receive during a whole-body CT scan, and it came up with some disturbing numbers. According to the study, the average scan exposes you to about the same level of radiation that's been measured in some atomic-bomb survivors who were as close as 1 1/2 miles to Hiroshima or Nagasaki. Moreover, if you have a full-body CT scan every year from ages 45 to 75, your cancer risk could increase tenfold. I'm no fraidy-cat when it comes to radiation--I stand boldly in front of my microwave when making popcorn--but this is the sort of statistic that grabs a man's attention.

Rebecca, the pleasant, blonde technician at Virtual Physical, is doing her best to calm me. "It's the equivalent of about four chest x-rays," she says when I point to the CT scanner--a flat bed with a horseshoe-shaped loop over it--and ask how much radiation it's going to zap me with. "That would be a lot if you were having one of these every few weeks, but most people only have a scan once every couple of years."

Rebecca says I remind her of a man she scanned a few weeks ago; he was also nervous about being made radioactive. "We found a spot on his lung, so it's all about weighing risks."

Spot on his lung? Still, I continue my hemming and hawing, until finally it's Rebecca who brings up the atomic-bomb study. "That wasn't really fair," she tells me, "because they totaled up the radiation you'd get if you had a scan every year. But you're only going to have it once."

I start to feel better, but suddenly I remember what Rebecca said earlier. "Didn't you just say a lot of people have these every couple of years?" I ask.

"Well, yeah, but . . ." She smiles, and I have no doubt she means well. "It's not gonna hurt you."

I smile and tell Rebecca I'd better think about this some more. Gopher or no Gopher, Internet discount or no Internet discount, I don't think I'm ready for my close-up.


When scans miss something
Whole-body scans are a fairly recent phenomenon. Although CT scans have helped doctors diagnose illnesses and injuries since the 1970s, it wasn't until the late 1990s that some physicians in California began using the machines to look not at the body parts of sick people, but at the entire bodies of healthy people. And not those referred by other physicians; people took it upon themselves to get scanned. The idea is simple: Take a snapshot of someone's insides, look for any funny business, then deal with problems--from blocked arteries to budding tumors--before they do serious damage.

The concept is so compelling that entrepreneurs have been opening centers at a fairly lusty rate ever since. In 1999 there were only a handful of facilities in the United States; 2 years later, the total was nearly 90; at last count, there were 161. Although there have been recent accounts of scan centers closing, that may be due to an industry shakeout after rapid expansion. Whatever the reason, there are certainly plenty left that are looking for customers.

As for who those potential customers are, at the moment, it's mostly "the worried well"--people who feel fine right now, thank you very much, but aren't taking chances about tomorrow. And they can obviously afford to worry, since the scans typically go for $500 to $1,000 each and aren't covered by insurance. (The latest trend is for resorts to offer scans, so you can sip mai tais and check out your spleen in one groovy vacation.)

The scans' popularity notwithstanding, those who look out for public health have never been all that enamored of them. Various entities--including the U.S. Food and Drug Administration, American College of Radiology, and American Heart Association--have come out against elective scans, and both Texas and Pennsylvania have banned them. The problem, say antiscanners, is that there's simply no proven benefit. Yes, you may learn that your arteries are blocked, but, as Grandy illustrates, that may not prevent anything. "Whole-body scans have been driven by the public's desire to have as much health information as possible, without knowing whether that information will help them," says Howard Forman, M.D., an associate professor of diagnostic radiology at Yale University.

Plus, there are drawbacks, including "false negatives" (the scan misses something, but you go on living obliviously) and "false positives" (the scan shows a problem that isn't really a problem). Indeed, though no studies have investigated false positives in whole-body scans, a 2003 study by the Mayo Clinic looked at 1,520 ex-smokers who had CT scans of their lungs. While the scans detected suspicious nodules in about two-thirds of the study participants, only 1.3 percent of the growths turned out to be malignant. Nearly everyone in this group, in other words, went through plenty of anxiety, expense, and, in some cases, pain (due to needle biopsies), only to find out they didn't have a life-threatening condition. And, as former nicotine fiends, they all had a high risk of malignant cancer; those who go for whole-body scans are generally low-risk folks, and their odds of a false positive are even higher.


Radiation from frequent full-body scans may cause cancer
If there's an epicenter of the scan debate, it would be Columbia University, where David Brenner, Ph.D., director of the center for radiological research, authored the controversial study that compared the fallout from whole-body scans with that of the Enola Gay's payload.

A shaggy-haired and slightly disheveled Brit who previously did a study of CT scans on kids (the radiation dosage, he found, was much higher than necessary), Brenner became concerned about whole-body scans while driving around Los Angeles one day.

"I heard an ad on the radio for one of these centers--they were offering a two-for-one deal," he says as we sit in a room down the hall from his office. "I hadn't realized how common they'd become."

Using population-based studies of Japanese atomic-bomb survivors, Brenner and his colleague, Carl Elliston, calculated the likelihood that radiation from a whole-body scan would cause fatal cancer. Their findings: A single whole-body scan gives you about a one-in-1,000 chance of dying of cancer. (If 1,000 people get scanned, one will develop cancer because of it.) "That's not very big," Brenner says. "You probably took a bigger chance crossing 168th Street to get here." But, he argues, if scans are to have any value as an early detector of disease, you'd have to be scanned fairly frequently--the way women get mammograms. And that's where the odds start turning ugly. If you have a scan every year for 30 years, he says, your risk of getting fatal cancer from the radiation rises to one in 100. "Now you're talking major risks."

Brenner clarifies that he's not against all CT scans; he has no problem with doctors scanning specific areas of the body in patients who have shown symptoms of a disease or are clearly at risk of one. Scanning individual body parts limits the amount of radiation, and a benefit is more likely. But he's skeptical about healthy people walking into places and ordering scans. "The problem is that the benefits of these scans for apparently healthy people is simply not known," he says.

Not everyone is a fan of Brenner's study. Even experts who agree with his argument--that whole-body scans have risks and no proven benefits--say his A-bomb comparison may be a bit over the top. Richard Morin, Ph.D., who chairs the commission on medical physics for the American College of Radiology, makes more or less the same point that Rebecca, the technician at Virtual Physical, made to me: Getting a dose of radiation split up over 30 years is not the same as getting it all at once. "Mammals have an enzyme that can repair chromosomes affected by low levels of radiation," he says.

In other words, having a 5-pound weight dropped on your foot once a year for 10 years might not be great, but it will probably do less damage than having a 50-pound weight dropped on your foot once. (Brenner, who is a member of the National Council on Radiation Protection and Measurements, acknowledges that the atomic-bomb comparison is not perfect, but he says it remains the best way to measure the long-term risks of radiation.)

Of course, the real venom for Brenner's study comes from people in the body-scan industry. "It's a piece of garbage," says Bruce C. Friedman, president of Heart Check America, a company that has several locations throughout the country and offers a range of scans. Friedman--who has an M.B.A., not an M.D.-- attacks Brenner's study in a number of ways. First, he argues that it's highly unlikely anyone would get as many whole-body scans in their lifetime as Brenner estimates--at most, patients would get scanned every 2 to 3 years, and only if they showed arterial blockages or had risk factors for lung cancer. Friedman also says his company's electron-beam CT scanners expose people to far less radiation than the scanners used in the study. Finally, he charges that Brenner and other critics ignore the potential value of whole-body scans. "Let's say we find some calcium in your arteries, and as a result, you start taking a baby aspirin and a statin," he says. "That reduces your heart-attack risk by approximately 70 percent. So it's an immediate 70 percent reduction in heart-attack risk versus a 1.9 percent increase in cancer risk.

If you look at it from that perspective, the benefit more than compensates for the risk." Perhaps. But if the scan finds no calcium in your arteries, or if it finds calcium and you choose to do nothing about it, you're merely left with an increased cancer risk. Friedman's underlying point is fair enough: People should be able to choose whether the risk (in this instance, a dose of radiation) is worth the reward (finding out if there's anything wrong with you). But in the case of CT scans, evidence suggests that patients have no idea what the risks really are. Last year, Dr. Forman and his colleagues at Yale published a study in Radiology in which they surveyed 76 patients about how much radiation they were being exposed to during a CT scan. "Abysmal," is how Dr. Forman describes people's awareness. None of the patients accurately estimated the radiation dosage, and only 5 percent knew a scan raised their risk of cancer (if only slightly).

That study was done on people in an emergency room, but those visiting body-scan centers may be even less informed, at least given the centers' ads. Judy Illes, Ph.D., a neuroethicist at Stanford University, recently authored a study in the Archives of Internal Medicine about the marketing practices of the body-scan industry and found ads that were misleading at best and deceptive at worst. Virtually none of the ads mentioned the potential radiation risks associated with scans, nor the possibility of false positives. "The risks were hardly highlighted, if at all," Illes says. Worse, 25 percent of the ads said the procedures were "FDA approved" when, in fact, the FDA has never cleared any CT system for whole-body scanning. Finally, Illes says a full third of the ads made medical claims that were unsubstantiated by scientific evidence. The study's bottom line: The ads "do not provide prospective consumers with the information that allows them to be truly autonomous, informed decision-makers."

I found out how misleading scan centers can be when I checked out Rebecca's claim about the amount of radiation given off by a single scan from Virtual Physical. "I don't agree with the estimate of four chest x-rays," says Richard Nelson, a lead technician at Philips, the maker of the Secura CT scanner used by Virtual Physical. In fact, the position of Philips is that the amount of radiation given off by the scanner is high enough that no one without a referral from a doctor should get one. The benefits to a healthy person don't outweigh the risks. It turned worse when I visited Virtual Physical's Web site. In its FAQ section, under a question about radiation exposure, the company states, "You will get about the same radiation exposure from a Virtual Physical as you would from sitting in the sun for 15 minutes."

"Oh, now that's a problem," says the ACR's Morin, who explains that yes, you do absorb radiation from the sun, but it's ultraviolet radiation, which is very different from the electromagnetic radiation emitted by x-rays or CT scans. UV light damages your skin, while electromagnetic radiation goes through to your internal organs. "The amount of electromagnetic radiation you encounter from being outside for an hour is about 1/10,000 of what you receive in a whole-body scan." (Virtual Physical's Florida-based owner, Robert Seaman, M.D., didn't return my call.)


Better guidelines for scan usage
The most feasible solution might be not banning whole-body CT scans, but instead instituting better guidelines. Right now, the FDA regulates the manufacture of CT machines, but it's up to the states to set rules for how doctors use them.

Those pushing for more supervision suggest voluntary professional guidelines, rather than government legislation. "I think all of the stakeholders here--academic radiologists, practicing radiologists, scan-center owners, medical ethicists--need to come together and talk about the risks and benefits of whole-body scans," says Illes. She proposes guidelines for who should be given scans, based on their health history, as well as mandatory fact sheets that clearly spell out the potential dangers--and rewards--of scanning.

Even some in the body-scan business think that's a good idea. "It would be terrific if everyone was required to tell you how much radiation you're receiving. If we all did that, a lot of the folks who are my competitors wouldn't be around much longer," charges Friedman. Curious, I ask him how much information Heart Check America gives its patients about radiation. "Our patients get as much information as they want to get," he says, noting that his staff is happy to answer questions. But what if patients don't ask about radiation risks--does the staff mention them anyway? "Well, no," he says. "But there is a consent form with radiation dosages."

It reminds me that sometimes the really important information is buried down deep--down where only the gophers can find it.