New PET/CT scanner provides clearer picture of potential abnormalities
By Patrice Sawyer Guilfoyle
Gone are the grainy pictures from an outdated PET system that made diagnosis challenging. A modern, advanced PET/CT system in the Jackson Medical Mall Thad Cochran Center takes its place, improving clinical, research and educational capabilities.
"It's like going from rabbit ears to high-definition TV," said Dr. Edward Green, PET/CT Center director and assistant professor of diagnostic and nuclear radiology.
The enhanced hybrid images produced by the system - one of eight in the world - provides better clarity for diagnosing cancers and has greater applications for research in Alzheimer's disease and heart disease. For the patient, the combination of the newest PET crystal detectors, the 64-slice CT and the most advanced computer processing available enables quicker scanning. This means less time in the machine.
Green said the average time for a patient to spend in the machine is 9-15 minutes to scan from the top of the head to the middle of the thighs, compared to up to an hour in the older PET scanner, which had no CT component. The PET/CT together defines the area and highlights the "bad spots" with a tiny amount of radioactive glucose, Green said.
Think of the CT (computed tomography) image as a geographic map and the PET (positron emission tomography) image as the weather system.
"Together they provide a clearer picture. With one component, it's like knowing a thunderstorm is present. With both, you can tell its exact location and its size. We can detect tumors as small as 2 to 3 mm," Green said.
Additionally, Green said the PET/CT Center is the only location in the state that offers intravenous and oral contrast during the scan, which provides a better characterization of abnormalities and helps the patient avoid the inconvenience and increased radiation exposure of a separate stand-alone CT scan with IV and oral contrast.
The new PET/CT system clearly showed the dramatic reduction of Tonya McKay's chest tumor. The 38-year-old mother of four said she had been sick for about six months before her health progressively grew worse.
"I was at the point that I couldn't breathe and would pass out walking from one side of the house to the other. I couldn't make a sandwich for my 3 year-old," said McKay of Union. That's when she sought medical attention and an X-ray revealed a tumor that was pushing her heart into the right side of her chest, collapsing a lung.
McKay got a PET/CT scan at the medical mall in July, but her condition made it difficult for her to lie flat for long. She had been sleeping sitting up because she had trouble breathing.
"With her large chest mass, coughing, shortness of breath and chest tube due to a pneumothorax, we scanned her in only nine minutes, rather than 45 minutes to an hour it would have taken at another PET/CT center," Green said. "That's where this machine really shows its value. That night, they started chemotherapy."
McKay had a 22 cm (8.58 in.) mass in her chest, but through chemotherapy, which she completed in December, she was told no signs of tumors had been found in a follow-up scan.
Old PET scan vs. state-of-the-art PET/CT scan
Word of this new technology has spread since the first patient was scanned in July. More than 400 patients have been helped by the system as of January.
Dr. Ralph Vance, professor of medicine, said the new system versus the old one is like comparing daylight and dark.
"We are now seeing things we've never been able to see before," Vance said. "For us as oncologists, this is a most valuable tool in our armory of fighting cancer. It gives us new insight and a really great deal of confidence in telling patients they have no evidence of disease."
Green said that's the main reason why the PET/CT system is important.
"We're really here to significantly improve our patients' lives," he said.
Five PET/CT technologists work in the new center scanning patients. Green is one of five radiologists that rotate reading the PET/CT scans. The others are Dr. Frederico Souza, Dr. Vani Vijayakumar, Dr. Andy Thaggard and Dr. Andrew Smith. They all work with medical students and residents to train and advise them on the new system, giving them experience with technology not found at many hospitals in the country.
The system combined with research has the potential to help advance knowledge in cardiology through stress tests that capture images of the heart and to advance knowledge in Alzheimer's disease through images of living participants in research studies.
Dr. Thomas Mosley, professor of medicine and director of the MIND Center, said he plans to use the new PET/CT system to study the pathology of Alzheimer's disease in participants. From the time the disease was first identified until today, the only way that Alzheimer's could be confirmed with 100 percent confidence has been through autopsy.
This past summer, a new radioactive dye was produced that attaches to the plaques that develop in the brains of Alzheimer's patients. Using a PET scan, the dye highlights the plaques, allowing them to be seen in participants. Mosley said he and researchers at the Medical Center have partnered with Johns Hopkins Medical Center to begin working with the new dye this spring using the sophisticated PET/CT system here at UMMC.
"We will be one of the first and largest studies to do this. It will tell us who has the pathology and who doesn't, and at what point in life it occurs. Our ability to image the plaques will allow us to better define the factors that promote the development of the disease," Mosley said.
"We are very excited about it because we believe it will have major implications for early diagnosis and development of new treatments."
To schedule a PET/CT, call 5-4RAD. Tours of the center can be scheduled by calling 5-9133 or 5-8960.