Narrator: This is Science Today. Ultrasound is used where x-rays don't work. The next generation of ultrasound machines is here, and Dr. Roy Filly of the University of California, San Francisco says it's better than the old model in a number of ways. The higher the resolution of an ultrasound image, the more detailed it is. There are two kinds of resolution.

Filly: One is spatial resolution -- if you have two structures that are side by side, can you separate them and tell that there are two instead of one?

Narrator: The old machine -- which isn't that old, since it dates from the 1980s -- had adequate spatial resolution. However...

Filly: The next is contrast resolution -- in that there is a, let's say, an organ like a thyroid gland, and within that organ there is a cancer, let's say. The lesion may be plenty big enough to resolve it spatially, but is it different enough from what surrounds it to resolve it contrast-wise?

Narrator: The new machine has improved contrast resolution, so the answer to that question will be "yes" more often. For Science Today, I'm Steve Tokar.