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What is a PET/CT Scan?

Mercy Medical Center's Siemens Biograph Truepoint positron emission tomography (PET/CT) high-definition imaging system markedly enhances the hospital's ability to detect cancer and greatly aids in treatment decisions.

PET/CT produces pictures of metabolism (cell activity), which cannot be obtained with CT, MRI or conventional X-ray. While PET uses radioactive isotopes, its technology differs from that of nuclear imaging.

PET/CT can find abnormalities such as tumors that might go undetected by other imaging methods now available locally. This information helps the physician determine which treatment would be most appropriate.

How does a PET/CT scan work?

PET/CT answers questions that CT scanning and MR imaging can't answer. To obtain PET/CT images, glucose containing a minute amount of radioactive isotopes is injected into the patient's arm. Glucose, a form of sugar found naturally in the body, accumulates in areas of rapid metabolism, such as tumors.

A PET/CT scan requires about 45 minutes, and is noiseless. The patient, fully clothed, lies comfortably on a table.

The PET/CT scanner, which resembles the large ring or "doughnut" of a CT scanner, records the radioactive decay, or breaking up, of the isotopes. This is done hundreds of thousands of times per second, from all angles.

The PET/CT computer reconstructs patterns of detected radioactivity into three-dimensional pictures of the body. Areas of rapid metabolic activity are highlighted, enabling physicians to pinpoint tumors and other abnormalities.

PET/CT scans are interpreted by radiologists with extra training in nuclear medicine.