detecting abnormalities) but relatively poor specificity (meaning that it wasn't good at distinguishing between malignant and benign abnormalities). MIS and NIR were more specific, and, when used in conjunction with mammography, they dramatically improved the probability of a correct diagnosis.

Such mixed results were not surprising. Developing and refining technologies like these is "an incremental process," says Paulsen. EvenMRI, which "is viewed as the most advanced medical imaging technology . . . wasn't eye-popping in imaging the breast because [breast cancer] is complicated."

None of the project leaders foresee their modalities replacing mammography, at least not any time soon. Mammography has been improved and developed over such a long period of time that it is firmly entrenched in the medical infrastructure of the United States. So instead of trying to supplant mammography, the researchers are looking for ways to supplement mammography. One way to gain a "toehold," says Paulsen, is to look at the settings in which mammography performs poorly, such as in dense breasts.

Advances in breast imaging tend to draw a lot of attention, Paulsen continues, "but in practice, these things move relatively slowly. I don't know of anything else that's on the horizon that is going to take over, so to speak. Tomosynthesis [which uses x-rays to create a three-dimensional view of the breast] is interesting, but it's a small perturbation on an existing idea."

There's no question that the DMS-Thayer collaboration is at the forefront of alternative breastimaging research nationwide, even worldwide. Researchers at several other institutions are working on NIR techniques (and all of them are collaborating with Dartmouth); a few teams elsewhere are in the early stages of exploring microwave-imaging technologies; a handful of centers are experimenting with MRE to image other parts of the body; and there have been at least a couple of commercial ventures using electrical impedance. But no other

There's no question that the DMS-Thayer collaboration is at the forefront of alternative breast-imaging research nationwide, even worldwide. A few other research groups are working on some of the techniques. But no other initiative in the world is as comprehensive and as well developed as the Dartmouth collaboration.

research initiative anywhere in the world is as comprehensive and as well developed as the Dartmouth collaboration.

"We're looking at all four [of the modalities] in a common setting," explains Paulsen, so that "we can look at them together and comparatively and synergistically."

The key to the success of the collaboration, says Paulsen, is the size of Thayer, DMS, and DHMC. "It's sort of the big company/small company paradigm," he explains. A big company "can continue to do its own thing, but to really turn it or adapt it quickly to something new just doesn't work because there's huge infrastructure and huge investment in teams. . . .We're a much more nimble, small enterprise." There are not too many places where radiologists, pathologists, and other clinicians are so accessible to medical engineers, he adds.

The deans of both Thayer and DartmouthMedical School are keen to exploit the strengths that Paulsen describes. "What distinguishes [Dartmouth] and gives us vitality . . . is our collaborative spirit," DMS's dean, Stephen Spielberg, M.D., Ph.D., has pointed out. He and his Thayer counterpart, Joseph Helble, Ph.D., formed

The deans of both Thayer and the Medical School are keen to exploit the strengths that Paulsen describes. . . . "What distinguishes [Dartmouth] and gives us vitality . . . is our collaborative spirit," DMS's dean, Stephen Spielberg, has pointed out. And that spirit is what has made the breast imaging projects so robust.

a committee composed of three DMS and three Thayer faculty to look at creating a new curriculum and new educational tracks, to formalize the merging of medicine and engineering that has been taking place informally for some time now.

Helble sees great promise in the openness on the part of DMS faculty to sharing their expertise and clinical space with engineering students and faculty. "As medicine becomes more and more technologically based," he says, "it's really important that the next generation of practicing physicians have a good understanding, a fundamental engineering understanding, of the capabilities and limitations of the technology they are going to be using."

Spielberg and Helble also make a special effort to encourage the faculty at both schools to work together. When either DMS or Thayer is interviewing a candidate for a faculty position who has interests in engineering or medicine, respectively, they make sure that the candidate also meets with faculty members at the other school.

"If you're looking for a place where there are going to be three or four people just like you," Helble says he tells prospective faculty, Dartmouth "is not the right place. . . . If you believe that all the intellectual excitement is at the interface between individual problems, then this is the place."

That willingness to collaborate across disciplines and to apply various approaches to the same research problem is what has made the breast imaging projects so robust.

Although it's likely that some of the modalities will progress farther and faster than others, none of the teams seem to view each other as competitors. They share computational and clinical resources and exchange information freely. Their attitude is that a lesson learned by one of the teams is a lesson that benefits all of the teams.

And ultimately, of course, patients.