02.26.04

By LISA WARREN
Greeneville Sun Health Editor
Laughlin Memorial Hospital will soon begin offering patients a new diagnostic imaging service, one that is expected to especially aid with cancer care here.
Called positron emission tomography, or PET, this imaging technique is used most commonly for cancer patients to "better distinguish noncancerous tissue from cancerous tissue," explained Chuck Whitfield, president and CEO of Laughlin Hospital.

PET scans are also used to determine the stage (extent of spread) of a cancer and to judge the effectiveness of cancer treatment, said Dr. Philip Marino, chief of radiology at Laughlin Hospital.  The procedure is used most often in patients with brain cancer, colorectal cancer, lymphoma, melanoma or lung cancer.

"PET scanning is not a new technology, but it recently has been expanded to include initial staging for malignant disease in certain diagnosis," said radiation oncologist Dr. John Boys.

"It also is very helpful to the oncologist in monitoring the follow-up of treated cancer patients to detect recurrent disease at the earliest possible time so appropriate clinical decisions can be made to maximize patient benefit," Dr. Boys said.

Although similar in size and shape to a CT (computed tomography) scanner, a PET scanner's capabilities differ greatly from a CT scanner.  Unlike CT and other traditional imaging techniques, a PET scan provides physicians with a color-coded image of the body's "function," rather than its structure or anatomy, Dr. Marino explained.  PET scanning uses positively charged particles (radioactive positrons) to detect subtle changes in the body's metabolism and chemical activities.

By looking at "body function," a physician can examine "the fundamental biological nature of disease that occurs early on, sometimes even before symptoms occur," Dr. Marino explained.

In addition to cancer care, PET scanning can also be used to evaluate patients with other illnesses:

* Brain disorders - PET scans can be used to evaluate neurological illnesses, especially epilepsy, and Alzheimer's disease and other dementias.
* Cardiac illnesses - PET scans can be used to evaluate how well the heart muscle is functioning in patients with coronary artery disease or cardiomyopathy.
PET scans also are used for research in other areas, including drug addiction, psychiatric illnesses and stroke.

Laughlin Hospital received certificate of need approval in late January to provide PET scanning services.  The hospital will begin providing the service this Friday.
The PET scanner will be located in a mobile unit in front of the hospital's Open MRI Center.   The service will be available once a week at the hospital.  "If the (patient) volume is there, and it becomes a justifiable service, then we will apply to get a fixed (permanent) PET scanner for the outpatient center," Whitfield said.

Jesse Taylor, director of radiology at Laughlin, said called PET scanning "a wonderful diagnostic tool" for physicians.  "It gives physicians very important early information," Taylor said. "It can detect cancers earlier and pinpoint the source of the cancer."

While other tests, such as blood tests, physical exams or other imaging procedures, may not be able to detect or confirm the presence of cancer, a PET scan can "detect cancer sooner and earlier," Taylor explained.

"We've had a lot of patients who have had to travel out of town to Knoxville or the Tri-Cities in order to undergo PET scanning," Taylor continued. "So we're happy that they will now be able to stay here in Greeneville and have this done."
Most PET scans take about an hour and a half, according to Diane Cohee, a nuclear medicine technologist with Shared PET Imaging, the Ohio-based company that is providing the mobile service at Laughlin Hospital.   Cohee explained that a patient is not allowed to eat or drink for at least four hours prior to the scan.

To begin the procedure, the patient is injected with a small amount of radioactive glucose through an IV.  Cohee stressed that the radioactive injection is not harmful to the patient.  According to a hospital brochure on the procedure, "the radiation exposure associated with PET is similar to a conventional CT scan."
After the injection, the patient must wait about 45 minutes to an hour before undergoing the scan, Cohee said. This is to allow the injected glucose to be distributed throughout the blood via the bloodstream.  For the actual procedure, the patient lies on a table that passes through the scanner.  Patients are advised to wear comfortable clothing for the procedure, Cohee said.

Following the scan, patients are able to resume their normal daily activities.