Overview
Technological advances are providing physicians with a better understanding of cell metabolism than ever before. At the forefront of these advances is the PET scan, which provides diagnostic information unavailable from other imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MR).

Unlike the MR and CT, which provide anatomic imaging of the physical structure of the body, a PET scan provides metabolic imaging that show how the body's organ systems function and how cells grow. The PET is able to show whether tissue is normal or abnormal based on cellular metabolism. This information can allow the physician to assess chemical and physiological changes related to metabolism. PET images can therefore demonstrate pathological changes long before they would be revealed in a CT or MR.

PET can help physicians with early diagnosis of a disease and provide additional information that can help predict a patient's prognosis for surgery. PET can also help physicians monitor a patient's response to treatment as well as identify distant metases that can affect treatment, helping curtail ineffective treatments and reduce unnecessary invasive procedures.

What is PET?
Positron Emission Tomography (PET) produces images of molecular-level physiological functioning, which can help physician identify normal and abnormal states. As in traditional nuclear medicine, PET uses radiopharmceuticals or "tracers," which are labeled with isotopes such as carbon, oxygen, nitrogen and fluorine. These isotopes mimic sugars, water, proteins and oxygen. As a result, PET can often reveal more about the cellular-level metabolic status of a disease than the CT or MR. PET can help diagnose a disease often before it shows up on other tests. PET can also show the progress of a disease as well as how the body is responding to treatment.

Current Applications
The three areas in which PET is making critical contributions are:
1. Oncology: lung cancer, breast cancer, testicular and ovarian cancer, recurrent colorectal cancer, lymphoma, melanoma, recurrent brain tumors, tumor-therapy monitoring, and assessing effectiveness of treatments such as chemotherapy.
2. Cardiology: coronary artery disease and myocardial viability.
3.Neurology and psychiatry: Diagnosis of Parkinson's, Alzheimer's, Huntington's, epilepsy, and stroke victims.

How PET Works
PET procedures may vary, but in general, a PET technologist administers the radioisotope by injection to the patient, who lies still for about 45 minutes, and then is scanned for approximately one hour.

Will my insurance cover PET?
Many insurance companies are reimbursing for PET procedures. Medicare has approved the following exams: lung cancer, recurrent colorectal, melanoma and lymphoma. Contact your insurer directly to learn about payment reimbursement.