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PET-CT Scanner

Beth Israel Deaconess Department of Radiology installed the first hybrid PET/CT scanner in the state of Massachusetts in April 2003. This technology allows the acquisition of images that show both physiology (PET scan images) and anatomy (CT Images), then fuses the two sets of images together to allow physicians to better understand the physiology of tissues seen on CT scan images.

PET (Positron Emission Tomography) scanning is a relatively new technology that has recently been seeing remarkable growth. More and more evidence is showing that PET/CT is the most accurate tool for imaging many cancers.

What To Eat And Drink The Night & Morning Before Your Pet/CT Scan

During The Exam

When you arrive, you will receive an injection of a diagnostic radioactive tracer. The tracer will take approximately one hour to travel through the bloodstream and distribute to tissues throughout the body. One hour after the injection, the scan will begin and will last for about 40 minutes.

How PET imaging works


Many cancers use more glucose (sugar) than most normal tissues. The Nuclear Medicine physician can take advantage of this by injecting glucose with a small amount of radioactivity attached to the glucose molecule. The PET scanner is then used to obtain images of the distribution of glucose metabolism throughout the body. The amount of glucose used by tissues in the body provides information to help guide further diagnostic and therapeutic options.

What is the purpose of the CT scanner? The CT scanner is needed because the major disadvantage of PET imaging is that the anatomic detail seen in a PET scan is inferior to that of a conventional CT scan. This means that although PET can see the general location of an area of abnormal glucose uptake, the exact localization of the abnormality can be difficult using PET images alone.

Anatomic Information Obtained with CT Scanning

fusion image

CT (Computed Tomography) scanning provides high-resolution images that show anatomy beautifully. But CT does not do a very good job of demonstrating physiology. Therefore, if an abnormality is seen on CT scanning, it is not always obvious if that abnormality is benign or malignant (cancer).

By obtaining both CT and PET images together, and fusing the images, the Nuclear Medicine physician can simultaneously see both anatomic and physiologic changes in the body that provide the most accurate information available today for the imaging diagnosis and localization of cancer.