Medical imaging service in a hospital in Savoie, France. Two technicians set up a patient for an MRI scan. (Photo by: BSIP/Universal Images Group via Getty Images)Universal Images Group via Getty ImagesWhole-body scans, using magnetic resonance imaging or ultrasound, are in vogue as companies and influencers promote them as “lifesaving.” While it’s possible that for some individuals such elective scans offer peace of mind, they can also produce false reassurance or needless workup and anxiety. For asymptomatic people, they’re generally not considered worth it.You may have recently seen direct-to-consumer advertisements as well as social media influencer messages promoting full-body scans. Company sponsors claim they provide easy and non-invasive ways to possibly find cancer or other conditions such as aneurysms before they cause health problems.But despite the hype surrounding them, no major medical groups, including the American Cancer Society and American College of Radiology, recommend these scans for people without specific indicators, such as a high risk of certain cancers.An MRI is a type of scan commonly used to look inside the body. In certain people, physicians may recommend a breast MRI; for instance, for a symptomatic patient or an asymptomatic person with a high risk of developing breast cancer. These types of MRIs produce images only of the body part being examined and are specialized for that purpose.On the other hand, a full-body scan images the whole body in one session rather than a specific area. This can be done with an MRI or ultrasound. Also known as sonography, ultrasound is a noninvasive imaging technique that uses high-frequency sound waves to create images of the inside of a person’s body. It’s often deployed in monitoring the development of a fetus during pregnancy and can have diagnostic uses as well.MORE FOR YOUDepending on the type of imaging used, full-body scans generally cost between $1,000 and $3,500, They’re often not covered by health insurance.Medical experts largely reject widespread use of whole-body scans as they say they’re neither clinically effective nor cost-effective. One of the biggest concerns is that someone with an incidental finding may then have follow-up computed tomography scans, as well as ionizing radiation and biopsy complications, searching for something that never would have caused symptoms. This can lead to unnecessary worry for individuals in addition to a misallocation of resources.The American College of Radiology states there isn’t “sufficient evidence to justify recommending total body screening for patients with no clinical symptoms, risk factors or a family history suggesting underlying disease or serious injury.”Jason Ryan, a cardiologist and the creator of Boards and Beyond — an online educational platform for medical students — suggests that it’s possible “whole body imaging can identify abnormal or diseased tissue that can be eliminated by early detection, which is the ideal screening result.” But, more often than not such testing reveals “normal tissue that appears abnormal,” “abnormal tissue that’s harmless and best left alone,” or “abnormal tissue that is untreatable and lethal no matter what we do.” In this context, when screening healthy asymptomatic people who don’t aren’t at high risk, the chance at an ideal screening result of identifying abnormal tissue that can be eliminated is very low. Ryan argues that there’s a far greater chance for findings that lead to invasive follow-up tests that yield more harm than benefit. This isn’t just the case for the individual patient. It can also overburden clinics and hospitals.Moreover, experts indicate that MRIs of any kind are usually not the starting point of a routine diagnostic work-up for any patient. Instead, after a patient provides a medical history and undergoes a physical exam, MRIs are deployed to confirm or rule out diseases or conditions as part of a proper differential diagnosis.Ultrasound scans have their own unique issues. Venk Murthy, a physician and faculty member at the University of Michigan Medical School, writes that there are things that ultrasound can’t pick up well due to imagery depicting shadows from bones or air and movement in the digestive tract getting in the way of clear images.As with any diagnostic, testing in the form of whole-body scans should provide a net benefit before used on asymptomatic people. In this context, screening ought not to turn mainly healthy people — sometimes called the “worried well” — into patients.The late professor of medicine at the University of Pennsylvania, William Kissick, once wrote, “a healthy individual can be defined as someone who has been inadequately studied.” This aphorism jibes with the idea that the harder one looks for a disease, the more incidence one may find regardless of whether test results are ultimately relevant to the patient’s health.