Posted by Article on 2/25/2002, 9:44 am

PET scans What is a PET scan? How is it administered? What will it show versus a chest CT scan? Unlike a computerized tomography (CT) scan, which shows only anatomic detail, a positron emission tomography (PET) scan also shows the function of tissue and organs. PET scanning provides information that can't be obtained by any other means. It allows for earlier detection of some types of cancer by revealing areas of increased metabolic activity that may indicate cancer. One example: Previously, doctors could only determine if cancer had spread to the lymph nodes if there was evidence of lymph node enlargement. PET scanning enables doctors to detect cancer in a lymph node before enlargement occurs, allowing for earlier detection and treatment of the cancer. In preparation for a PET scan, a radiologist introduces — usually by injection — a small amount of radioactive substance into the body. Scans taken during the procedure show how various organs or tissues metabolize the injected substance. The test takes 60 to 90 minutes. PET scanning is rarely used alone but typically in conjunction with X-rays or a CT scan for comparison. PET scanning is still evolving but already has many diagnostic applications, such as: Assessing various metabolic processes. Measuring the size and effect of a heart attack. Indicating the effectiveness of medications on specific tissue. The procedure is expensive and usually available only at major medical centers. Article Online ******* Mayo Clinic Scottsdale News Friday, July 20, 2001 PET Scanner Revolutionizes Diagnosis of Cancer and Other Deadly Diseases Mayo Clinic Scottsdale is one of only three centers in Arizona with this technology SCOTTSDALE, Ariz. – Patients with diseases such as cancer, epileptic seizures and coronary artery disease can now receive more accurate diagnosis and improved care, with less need for invasive biopsies and fewer surgeries because of a new Dedicated Ring-Detector PET (Positron Emission Tomography) scanner. Mayo Clinic Scottsdale is one of only three centers in Arizona to provide this technology, which is one of the most powerful and accurate diagnostic imaging machines available today, According to Michael C. Roarke, M.D., Director of Nuclear Radiology at Mayo Clinic Scottsdale, CT and MRI show anatomy well, but they often don’t indicate whether a lesion is benign or malignant. Dr. Roarke adds that PET shows the function of the lesion and this helps differentiate between benign and malignant tissue. For the millions of people suffering from cancers such as lung, colorectal, esophageal, melanoma, and lymphoma, the PET scan can identify areas of cancer spread, distinguish between scar tissue and active tumor, and help determine cancer response to chemotherapy and radiation therapy. As an alternative to biopsy as a diagnostic tool, the PET scan is effective in characterizing nodules seen in the lung on chest x-ray or CT. For example, if the PET scan shows that a lung nodule is benign, then the nodule can be monitored with follow-up chest imaging rather than having the patient undergo an invasive needle biopsy or surgery. If the PET shows that the nodule is malignant, then the patient can proceed to surgery without undergoing the biopsy. Cancer facts are startling. In Arizona alone, it is estimated that there will be more than 21,000 new cancer cases diagnosed this year, and nationwide, an estimated 1.3 million new cancer cases will be diagnosed this year. “PET scanning is a 21st century tool that will play a vital role in medical care,” says Dr. Roarke. “This technology will provide physicians with the ability to assess the function of tissues in the body, which, up to now, has not been available. ** Editor’s note: Dr. Michael Roarke and a PET scan patient are available for interviews and photos by calling Anne Tewksbury, 480-301-3551.

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