| Newsletter Spring 2005
Spring 2005 Articles
PET CT Scans
A new imaging scan technology is having a huge, positive effect on patient care at Wenatchee Valley Medical Center. Positron Emission Tomography (PET) scan is a highly sensitive scan that, when used together with Computerized Tomography (CT, also known as the CAT scan), provides precise information physicians can use to treat a variety of diseases.
The PET/CT scans provide a way of learning precise information about a disease once it has been diagnosed so physicians can determine the most accurate and useful treatment. The PET scan detects metabolic activity, while the CT scan pinpoints where the activity is in the body.
Radiologists David Levitsky, MD, and Vasudev Bhide, MD, explain.
“The PET scan is a nuclear medicine test,” says Dr. Levitsky. “We inject radioactive glucose which has a very, very short half life, so it’s not at all dangerous to the person who gets it. The radioactive glucose goes to sites of high metabolic activity, which tumors usually have. That’s why it’s able to detect abnormalities at such an early stage.”
“It’s a functional scan,” says Dr. Bhide. “We’re looking at metabolic activity in the body. The basic presumption here is cancer cells are metabolically hyperactive compared to normal cells.”
“PET is outstanding at localizing abnormalities,” says Dr. Levitsky, “but it’s not very precise. It will say that there’s an area of abnormality, for example, in the abdomen or the pelvis, but it doesn’t tell you where in the abdomen or pelvis it is.”
That’s where the CT scan comes in. The CT scan has been around for over thirty years. It’s an x-ray technique that produces detailed picture of the body’s anatomy – it’s internal structures. Unlike traditional, two-dimensional x-rays, the CT scan produces cross-sectional images, like slices of bread.
“CT uses radiation to very precisely define anatomy,” says Levitsky. “What we’re able to do is fuse the CT and PET images so that we get the best of both worlds, which is the detection of metabolic abnormalities and precise localization.”
“The PET/CT fusion is something new,” explains Dr. Bhide. “When you superimpose one image over the other, it’s very precise. Each one alone would not be as good. Together, they make a big difference.”
The CT/PET images are read by radiologists, like Dr. Levitsky and Dr. Bhide, who are specially trained to interpret the images and correlate findings with other examinations and tests.
One of the primary uses of the technology is cancer staging. Staging is the process of assessing the size and location of a patient’s cancer. Identifying the cancer stage is one of the most important factors in selecting treatment options.
“PET/CT is the gold standard for staging, and staging allows us to treat patients accurately,” says Dr. Bhide. “The accuracy of the spread of disease is very important in deciding treatment options. It prevents unnecessary surgeries, and it lets oncologists give very accurate prognosis to the patient.”
Along with cancer staging, PET images are useful in neurological disease. It can detect the brain's biological changes that come with Alzheimer's disease, Parkinson’s disease, and even brain seizure activity.
PET images are also the most accurate test to determine if coronary heart bypass surgery would be the appropriate treat
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