Originally created 04/23/04

Scanners assist doctors, patients



Dr. Hadyn Williams points to a row of gray-colored images on a computer screen showing three views of a mass in a patient's spinal cord.

With these computerized tomography (CT) scans, though, it's impossible to tell what the mass is.

On the next row of the screen, the section chief of nuclear medicine at Medical College of Georgia Hospital focuses in on three fiery red images of the same spinal cord, this time noticing an illuminated hot spot.

However, with these images from a positron emission tomography (PET) scan, he cannot know exactly where the lighted - or infected - area is.

That's when he pulls up a combined picture of two scans, and it all makes sense.

"When I fuse the two together I'm able to localize where the tumor is and see the shape of it," Dr. Williams said.

The technology, a PET/CT scanning system, provides far more detail of cancerous or diseased areas in a shorter period of time.

In August, MCG became the first hospital in the region and one of only 115 nationwide to use the system.

Since then, 450 patients - adults and children - have had PET/CT scans.

Staff technologist Laura Norman said the scans are used to diagnose various forms of cancer, to do brain studies and to study the origin of seizures.

A CT scan uses X-rays to produce cross-sectional images of internal structures of the body to locate tumors. With PET scans, technicians inject a glucose derivative labeled with a radioactive tracer into living tissue to distinguish diseased areas from normal areas.

The problem, Dr. Williams, said, is that doing the tests separately means the patient could be in a slightly different position each time.

Also, to look at the pictures produced from the two scans, the physician has to hold them up next to each other and then imagine how they overlap.

With the PET/CT scanning system, this is done automatically on the computer.

First, the patient is set up in an incubation room where he is injected with glucose.

The patient then lies down on a flat bed, and the technician slowly slides him through the CT and then PET scan.

Dr. Williams said the CT scanner takes less than 30 seconds, while the PET scan lasts 20-30 minutes. Throughout, the patient can communicate with technicians in the next room.

MCG was the second facility in the world to use an open system, with a space between the CT and PET scan portions.

"It's so the patient can see out and hopefully won't feel as claustrophobic," he said. "It seems to make them more able to tolerate the conditions."

Reach Dena Levitz at (706) 823-3339 or dena.levitz@augustachronicle.com.

PET/CT scanners

Devices are used in:

  • Diagnosing cancers
  • Monitoring a tumor to see whether it’s spreading or has been eliminated
  • Neurological testing
  • Looking for seizures, particularly in children
  • Checking condition of heart tissue before surgery
  • Radiation therapy planning