PET Scan

Serving the Greater Boston area, radiologists at the Newton-Wellesley Hospital Department of Radiology perform hundreds of PET scans annually. To make an appoint for a PET scan, or to speak with a member of our team, contact our Radiology Department.

What is a PET/CT Scan?

A positron emission tomography (PET) is a standard imaging tools that allow clinicians to pinpoint the location of cancer within the body before making treatment recommendations. The combination of PET scans and CT scans allow clinicians to detect changes in cellular metabolism. This combination allows for earlier and more accurate detection of disease.

How do I prepare for a PET Scan?

No food should be eaten for 6 hours before your test. (Diabetic patients may eat up to 4 hours prior to appointment time.) Drinking water is allowed and encouraged. It is recommended that the night before the exam you drink 2-4 glasses of water to ensure hydration prior to the exam.

Meal Ideas

Your last meal before the scan should be high in protein and low in carbohydrates.

Examples include:

  • Dinner: steak, baked chicken, fish, cheese, asparagus, broccoli, mushrooms. No pasta, potatoes, rice or bread.
  • Breakfast: eggs, bacon, sausage. No breakfast should be eaten if you have an appointment before noon.


Continue to take any medication prescribed by your physician. If you have been advised to take your medications with food, eat nothing more than a few soda crackers 4-8 hours prior to your exam.

What to Avoid

Avoid caffeine, sugar, tobacco and heavy exercise for 24 hours prior to your exam.

What to bring and wear

  • Insurance cards
  • Previous CT scans, x-rays and prior PET exams, medical history, pathology reports
  • Patients should wear loose, comfortable clothing. Clothes should be free of zippers and snaps.
  • Jewelry should not be worn

Please arrive 30 minutes before your scheduled appointment.

What will happen during the exam?

Before the scan, a technologist will insert a small i.v. line into your arm. A small amount of FDG, a form of glucose, will be injected through the i.v. line. This is painless. Once injected, you will be asked to rest quietly for 30 to 60 minutes to allow the FDG to distribute in your body.

The technologist will ask you to lie on the scanner table, which will then slowly pass through the PET scanner. The PET scanner detects and records the signals the tracers emit. The signals are then reassembled into actual images through a computer.

In some instances your physician may request a second injection of IV contrast to better visualize anatomy. This injection will be given while you are being scanned.

How long will the procedure take?

Every PET exam is different but most scans will take approximately 30 to 45 minutes.

What will happen after the exam?

After the exam, the technologist will process your images using a computer. A radiologist will evaluate the images within 24 hours and dictate a report. A transcription of the report will be typed and sent to your physician.

You should feel fine following your PET scan. There are no known side effects from the injected FDG.

How will I receive my results?

You will get the results of the exam from your doctor.

Important: If there is any possibility that you are PREGNANT or NURSING a baby, please speak with your referring physician before your scheduled appointment.


We are accredited by the American College of Radiology (ACR) and are licensed by the Massachusetts Department of Radiation Control.

More Information
For more information, please visit the  Radiological Society of North America's and American College of Radiology's website on PET and radiologic procedures.

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