It has become popular for some people to have yearly wholebody scans (CT scans, formerly called CAT scans), using X-rays, just to see if they detect anything suspicious. A number of medical people have recently questioned the advisability of such scans, due in part to the radiation they impart. Typically, one such scan gives a dose of 12 mSv, applied to the whole body. By contrast, a chest X-ray typically administers 0.20 mSv to only 5.0 kg of tissue. How many chest X-rays would deliver the same total amount of energy to the body of a 75 kg person as one whole-body scan