Hidden Specialties
Meet the doctors of sleep, images, and microscopes
"Imaging with light is very complicated," Schnall says. Unlike X-rays and other high-energy beams and particles, light is absorbed or scattered by all sorts of tissues and cellular components. The challenge, says Schnall, is to transform a scattered signal into a sharp image. If he can solve that mathematical trick, Schnall says, the research may lead to safer, cheaper, and less painful breast-imaging devices. They could even be used by a patient at home.
Neck-up specialists. A new subspecialty, interventional radiology, has moved beyond using forms of radiation to find and diagnose diseases to treating them (story, Page 59). Neuroradiologists, who specialize in imaging everything from the neck up, do some interventional procedures as well, says Elias Melhem, Penn's head of neuroradiology, although most of their work is still diagnostic.
Say a patient is referred to a neuroradiologist with symptoms indicating a possible brain tumor. Neurosurgeons used to spend hours trying to deduce the tumor's location before opening the cranium. Now, says Melhem, "what used to take 13 hours of examinations and thinking takes 10 seconds. We have the tools to tell the surgeons exactly where the tumor is" --and to aid in removing the entire tumor but none of the brain. Intraoperative MRI s, miniature wand-shaped versions of the more familiar room-size magnetic rings, can make 3-D images of brain structure right in the OR so the surgeon can see whether all possible vestiges of the tumor are gone before closing up the cranium.
New uses for medical scanning technologies are everywhere these days, it seems. The worried well can walk into private clinics for whole-body CT scans, to make sure their bodies are not harboring tiny lung tumors, colon polyps, or some other nascent problem. And for expectant parents who can't wait to get started on the family photo album, ultrasound booths are popping up in shopping malls, selling prenatal portraits for $200 or more a session (probably safer than the X-rays shoe salesmen in the 1940s and '50s used to take of their customers' feet to ensure a good fit in a new pair of Oxfords, but the FDA warns that there could be unknown risks to the fetus from repeated exposures).
Schnall doesn't see anything wrong with people electing to pay for a full-body scan, just in case--so long as they know they might be asking for trouble. Sophisticated multislice and electron beam CT scanners are great at detecting unwanted growths, as well as lots of false positives--blips on the images that look bad but turn out, after needless worry and perhaps even surgery, to be nothing more than spots of scar tissue and other harmless stuff. "Yeah," says Schnall, "you might find something bad. But you're more likely to find lots of stuff you're better off not knowing about." Stamp this one "buyer beware."
PATHOLOGY
For much of the day, the pathologist's world is painted in swirling blues and orangy pinks. Every tissue sample removed from a hospitalized patient, from an entire massive tumor to a small clump of cells, makes its way to the pathology lab to tell its story under the microscope. The task of coaxing forth the narrative seems surprisingly uncomplicated, at least at first. A specimen is dipped into two dyes. Hematoxylin highlights cell nuclei in purple-blue, and eosin stains other parts of the cell in variations on orange.
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