Under Your Skin

by Ted S. McGregor Jr.


Like many a mad scientist of his time, Wilhelm Roentgen was a tinkerer. One November night in 1895, the physicist went to his basement lab to play with cathode rays -- all the rage among his buddies at the time. That night, he went a little wild and crazy by pumping bursts of electricity into the cathode, and, as happens with so many big discoveries, he accidentally discovered X-rays -- a name he gave them indicating their yet-to-be named status. A few weeks later, he had his wife Bertha hold her hand up to a photo plate for 15 minutes while he bombarded it with the mysterious rays, and the first picture of the inside of a human body was created.


Now, more than a century later, his little discovery has evolved into one of the most powerful tools in health care. But the biggest burst of innovation in seeing under people's skin since that time may have arrived just this past decade. To begin with, increasingly powerful computers have allowed radiologists to go digital.


"It's changed dramatically since the old days when they just read X-rays up on a lightbox," says Dr. Robert Handy, a neuro-radiologist with Inland Imaging for the past nine years. "I never touch X-ray film anymore."


Handy talks about how as recently as five years ago, if you had, say, stroke symptoms, and you lived in Colville, it could take five days to get your film looked at by a radiologist. Today, via a powerful computer network, a radiologist in Spokane can look at an image just seconds after it's taken, as can a specialist -- and they can all confer over the phone while they look at the same image. (Inland Imaging reads scans for 14 rural hospitals in the region in this way; their docs looked at about half a million images in 2003.)


For the stroke victim, a course of blood-thinning drugs can be prescribed in minutes instead of days. "In certain types of illnesses," Handy says, "time is critical." But advances in raw computing power are allowing for more complex scans to be taken at a faster rate. And now, Inland Northwest patients are poised to have access to the very latest in imaging, the PET/CT scanner. Inland Imaging has purchased one -- for a cool $2 million -- and it will be in use at their branch in the Sacred Heart Doctors' Building on Eighth Avenue in November.


"This really is a big change," says Dr. Ed Holmes, a specialist in nuclear medicine with Inland Imaging.


The CT scanner -- for Computerized Tomography -- functions the way an old X-ray machine works, but in far greater detail, scanning a person in a series of slices. Doctors get a very clear picture of anatomy from a CT scan.


The PET scanner -- for Positron Emission Tomography -- hones right in on tumors, but it's pretty fuzzy on the surrounding anatomy. Patients are injected with a glucose solution infused with radioactive particles called FDG. Anything in the body that craves sugar -- like the brain, an infection or a tumor -- sucks up the glucose and the radioactive material with it. The PET scanner picks up those "hot spots."


In the old days -- which in the rapidly evolving radiology game means three or four years ago -- doctors would often compare a CT scan to a PET scan to try to determine the location of a tumor. Is it just in the lung? Has it spread into bone? It was usually hard to tell with two different scans, says Dr. Phil Curtis, another nuclear medicine specialist with Inland Imaging. What if you could see both scans together?


"There's not a day that goes by when I don't read a PET scan and wish I had a CT scan to look at with it," says Curtis.


Well, the wishing is about over, as that's precisely the function of the PET/CT scanner -- one of the most powerful new weapons in the war on cancer. A patient can be run through the machine in 30 minutes, and it will take both a PET and CT scan, then -- through fast processors inside the computer -- render the two scans on top of each other. In 3-D.


Yeah, it's cool stuff. But it can also save lives.





Let's say a patient comes in with a pesky pain in his side. Five years ago, with a doctor's referral, Inland Imaging could have taken both a CT scan and a PET scan. They would have been able to determine if there was a tumor and where, in general, it was located. Today, with the PET/CT, it will get a lot more specific. Where the tumor is located determines how it will be treated and how effective that treatment will be. In the old days, if they weren't quite sure what was going on, they'd just operate.


"Literally, you'd open people up and look around to see what you could see," says Curtis. "Well, we don't really do exploratory surgery anymore."


And beyond exploratory surgery, the greater detail the PET/CT provides is also a powerful tool in determining whether surgical removal of a tumor is appropriate. The detailed image also allows oncologists -- doctors who treat cancer -- to target their radiation treatments carefully so as not to hit healthy organs and to make sure all the sick parts are treated. The machine is also used to detect infections in heart patients, and yet another application -- one just approved by Medicare -- is to use the PET/CT scanner to study the brain to determine whether dementia is caused by Alzheimer's or not, which dictates the course of treatment.


But the avoidance of surgery is the primary reason these machines have been approved for reimbursement under Medicare, which sets the standards for insurance companies across the country. When you look at the price tag, it's not hard to understand why health care costs in the United States continue to rise. We're getting really good at this health care thing, but it's not cheap. By Medicare's calculus, however, preventing unnecessary and expensive surgeries saves the system far more than the cost of the scan. And that's good news for patients, too.





Rocket Science


When you go in for a PET scan, you're first injected with a glucose solution that includes low doses of radiation. The solution is called FDG, and the radioactive elements are called "tracers" for the images they create. Tumors suck up the glucose, and the PET scan sees the radiation in those "hot spots." This is why some radiologists specialize in nuclear medicine -- so it really is a little bit like rocket science.


But since this material is radioactive, it degrades --in this case, fairly quickly. So in order to use a PET scanner, you need access to a cyclotron to manufacture the FDG solution. And it needs to be nearby. Currently, hospitals in Montana have a hard time scheduling PET scan, because the cyclotron in Seattle -- where hospitals and clinics with PET scanners in the Inland Northwest get their FDG -- is too far away. And Seattle's cyclotron is running overtime to keep up with demand.


So plans are currently in the works for Petnet, the company that manufactures the FDG, to build a cyclotron for the Inland Northwest and points inland (like Montana) near the Spokane International Airport.


Dr. Ed Holmes, a nuclear medicine specialist with Inland Imaging, says the future of PET scanning is exciting, as researchers are constantly trying to develop tracers with new radioactive signatures to pinpoint other features of tumors. One in development is reputed to be able to communicate the tumor's rate of growth.


But there are no entirely new technologies on the horizon, says Holmes. Sorry, no little hand-held scanners a la Star Trek that tell you everything about a patient with a quick wave of the hand -- yet. But the insights the existing technology offers may reach a popular audience, even if it's not all covered by insurance. After all, even a healthy 30-year-old might want a peek inside to see if any trouble is brewing. Well, in Japan, some health clubs own PET scanners and are already offering the service to their members.





Publication date: 09/30/04