When people who feel fine get a full-body MRI scan, they often find weird little things that aren’t cancer—but those weird finds happen more often than actual cancers are discovered.

When healthy people without symptoms get a full-body MRI scan, doctors often find weird little things that aren’t actually harmful—but those findings can lead to more tests and stress that might not be needed.

Using a full-body MRI scan on people who feel fine can sometimes find hidden health problems they didn’t know they had—and some of those problems might need a doctor’s attention.

When doctors scan the whole body with an MRI on people who feel perfectly fine and have no symptoms, they find cancer in about 1 in 64 of them.

When doctors scan the whole body with an MRI in people who feel fine and have no reason to think they have cancer, they find cancer in about 1.57 out of every 100 people.

When doctors use whole-body MRI scans on people who feel fine and aren’t sick, they find cancer in only about 1.57 out of every 100 people — so it’s not very good at catching cancer early in healthy folks.