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PET/CT (Positron Emission Tomography/Computerized Tomography) Scanning


Dr. Richard T. Hoppe discusses the advantages of PET/CT scanning

Stanford is the first health care institution in Northern California to offer patients a powerful new diagnostic imaging system known as Positron Emission Tomography/Computerized Tomography (PET/CT) scanning.
This hybrid technology combines the strengths of two well-established imaging modalities in one imaging session to more accurately diagnose and locate cancers while increasing patient comfort.

How It Works

What PET Scans Do

PET, or positron emission tomography, monitors the biochemical functioning of cells by detecting how they process certain compounds, such as glucose (sugar). Cancer cells metabolize glucose at a much higher level than normal tissues.
By detecting increased glucose use with a high degree of sensitivity, PET identifies cancerous cells -- even at an early stage when other modalities may miss them. However, PET cannot pinpoint the exact size and location of tumors to a precision necessary for optimal diagnosis and treatment planning.

What CT Scans Do

CT, or computed tomography, yields a detailed picture of the body's anatomical structures by taking cross-sectional images or X-ray slices of the body. While CT does an excellent job of depicting structures and anatomy, it may miss small or early stage tumors.

How a Combined PET/CT Scan Improves on Separate Scans

Doctor and patient with a PET/CT scanner

Currently, physicians can overlay the results of PET and CT scans performed separately to identify and locate tumors. However, because a patient may not be positioned identically for both scans, the two images can be difficult to line up exactly, degrading the accuracy of the diagnostic information.
The combined PET/CT machine allows physicians to rapidly perform both scans in one session without having to move the patient. This means physicians can precisely overlay the metabolic data of the PET scan and the detailed anatomic data of the CT scan to pinpoint the location and stage of tumors.


With PET/CT, Stanford physicians can make more accurate diagnoses, develop more targeted treatment plans, and do better, less-invasive treatment monitoring, which should result in improved patient outcomes.

Increased Patient Comfort

A PET/CT scan is noninvasive, painless and takes about 30 minutes. Along with providing better imaging data, it notably increases patient comfort and convenience by reducing the number of scanning sessions a patient must undergo. The procedure is covered by private insurance and Medicare. Is it really appropriate to have the insurance information here? Insurance coverage is not mentioned in relation to any other treatment.

Better Data, Better Treatment Plans

Clinical research has shown that in comparison to a PET scan alone, PET/CT technology provides new information that can alter a patient's treatment plan to better target the cancer in approximately one-third of the cases.

In one example, the PET/CT scan of a lung cancer patient revealed not only the original tumor on the lung -- which a previous CT scan had found -- but an additional tumor the CT missed: a small, early stage lesion in the neck.

Based on the CT alone, the physician would have recommended surgery, but the additional tumor found by PET/CT indicated that the cancer had spread and was inoperable. Based on this information, the physician proceeded with radiation therapy, giving the patient a better chance of survival.

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