Medical Imagers Lower the Dose  Radiation-lowering techniques
were in the works even before studies showed a danger  Photo:
Ian Hooten/Getty Images; Images: GE Healthcare(2)  Catch Fewer
Rays: Tricks of image reconstruction spare the patient by making
every X-ray photon count.  Recent research documenting that CT
scans increase the risk of cancer has biomedical engineers
looking for new ways to reduce patients' exposure to ionizing
radiation.  CT scans, which use multiple X-ray images to build
up cross-sectional and 3-D pictures of structures inside the
human body, have soared in popularity in recent decades. A study
published in December's Archives of Internal Medicine found that
the number of CT scans grew from 3 million in 1980 to roughly 70
million in 2007. Those 70 million scans could eventually lead to
29 000 cancers, according to the same study. For each year's use
of today's scanning technology, the resulting cancers could
cause about 14 500 deaths.  But the makers of CT scanners are
already taking st