And for the patient, it requires only about one-tenth the exposure to the dangerous rays as a conventional X-ray, according to Photobit.

As the son of a radiologist whose office was in our home, I grew up seeing conventional X-rays displayed on my father's light boxes.

Like a conventional X-ray, radio visiography can show the interiors of teeth, but it does so instantly, without film, development time or chemicals.

And because it requires only 20 percent of the radiation of conventional X-rays, patients and technicians suffer less exposure.

The new technologies appear to offer faster treatments, less exposure to radiation than with conventional X-rays and, in some cases, less pain and suffering.

Dr. Christensen, whose center has evaluated digital radiography, said the quality of its images was about the same as for conventional X-rays.

At the same time, doctors are going beyond conventional X-rays to offer ultrasonic imaging that, for example, looks for abnormalities in the heart or the fetus.

In what cases is magnetic resonance imaging worth the cost, and when will CT scans or conventional X-rays suffice?

In contrast to conventional X-rays, photographic developers are not needed.

Even costlier, if it would ever be required, is a new generation of equipment to detect explosives that cannot be found by conventional X-rays.