In fact, most such conditions are fairly uncommon. Take Pettitz's kidney cancer. The Cooper Clinic in Dallas used EBCT on nearly 12,000 consecutive patients to detect kidney tumors and found 25, according to a report last November. That's less than 1 patient in 450. And Pettitz's doctor almost certainly would have felt the growth during a physical.
Heart disease is different.
A large part of the population either has it or will, and CT scanners easily pick up the calcified plaque that gives it away. Hence, far more studies have explored the pros and cons of heart scans than of any other kind. Most of the studies are of EBCT, because the technology was developed for that purpose. These scans are a standard tool for diagnosing tumors and other problems. New spiral scanners shrink the width of the slices, giving the assembled image more detail.