PET-CT | Emerson Hospital
​PET/CT is an advanced imaging tool that combines two scanning techniques—positron-emission tomography (PET) and computerized tomography (CT)—in one exam that not only shows what an organ looks like, but also how it’s functioning.


A PET scan measures metabolic activity and molecular function by using a radioactive imaging compound that can be injected. The PET scanner detects the radiation emitted by the glucose, and the computer generates three-dimensional images of tissue function or cell activity in the tissues of your body.
PET/CT services are available at Emerson Hospital’s Center for Specialty Care in Concord.

Why PET/CT is performed

PET/CT is mainly used for diagnosing and staging cancer, determining if cancer has spread (metastasized), and evaluating how someone is responding to cancer treatment. When combined, the two scans can provide an accurate picture of the cancer’s location, as well as the metabolic activity within cancer cells.

PET/CT is also sometimes used to differentiate between dementia and Alzheimer's disease. 

Studies that are available include:
  • 18FDG - used for general oncology imaging
  • Axumin, Fluciclovine F18 - imaging in men with suspected prostate cancer recurrence based on elevated blood prostate specific antigen levels following prior treatment
  • Ga-68 Dotate - used for the localization neuroendocrine tumors

What a PET/CT scan involves

First, the radiologist will inject small amount of radiotracer into a vein (the tracer can also be breathed in as a gas, taken by mouth, or injected directly into an organ).
Depending on which organ is involved, it may take from 30 to 90 minutes for the radiotracer to reach the targeted part of your body.

Meanwhile, you’ll be asked to sit still and not talk. When you’re ready, you’ll be taken to a special room for the scan and lie down on a cushioned, motorized examination table.

The PET/CT scanner is shaped like a large doughnut. The motorized table slides through the donut “hole” into a short tube. 

When you move into the scanner, the tube rotates around you, taking images. To ensure the images as clear as possible, you must lie as still as possible. Depending on which part of your body is being scanned, this should take about 30 minutes.

The entire testing procedure typically takes about 2 hours, and most patients can go home as soon as the scan is finished. You should consumer plenty of liquids to flush the radioactive glucose out of your system more quickly; it should leave your body completely within 3 to 4 hours. 

To obtain test results

By law, this requires a signed medical records release form and photo identification. To make a request, please call:

Schedule an appointment

To schedule an appointment for a PET-CT, please call 978-287-3003.