X rays yield sharp, microscopic 3-D images.

Every cell tells a unique story in three dimensions. Biologists studying subcellular structures--a maze of bulbous bits and twisted strands -- struggle to visualize their true form.

It's a difficult task, given the absence of a simple technique for imaging cellular components in three dimensions without damaging the objects under view.

Approaching this problem from a new angle, Waleed S. Haddad, a physicist at the Lawrence Livermore National Laboratory in Livermore, Calif., and his colleagues describe a new type of "ultrahigh-resolution X-ray tomography." Their report appears in the Nov. 18 SCIENCE.

"In the long run, we want to get to the point where we can image live cells in three dimensions or image them as close as possible to their living state," Haddad says. "We're not there yet, but that's what we're aiming for."

In that quest, Haddad and his coworkers have devised a three-dimensional visualization method that uses low-energy X rays along with a scanning transmission X-ray microscope to produce some of the highest-resolution images ever obtained.

"We were able to reconstruct some features of our test objects with a depth resolution of about 1,000 nanometers," says Haddad. "This is about 10 times greater than people have been able to achieve so far."

In addition, they achieved this resolution by combining only nine images. Other methods of X-ray tomography -- such as the CT scanning commonly done in hospitals -- may require 100 to 1,000 separate pictures to produce a good-quality three-dimensional image.

To test their technique, the scientists fashioned tiny plates of silicon nitride and placed patterns of gold on them. Details in the patterns ranged from 650 to 1,000 nm in length and depth. Carefully rotating the sample, they took nine two-dimensional snapshots. Using a computer, they then combined the pictures and constructed a three-dimensional image.

The researchers are now turning their attention to making three-dimensional pictures of dried sperm cells. The next step, they say, will be to image wet sperm cells.

If all goes well, they will then attempt to obtain three-dimensional images of live sperm.

"It's not easy," says Haddad. "It's hard to do without killing the cells. The key is to lower the X-ray dose. At some point, we want to try a pulsed X-ray laser so that we can collect all of the information needed in a very short time, so short that nothing moves during the exposure. But we're not at that stage yet."

To Haddad, three-dimensional images of live cells beckon "like a holy grail."