Clinical Indications of PET
Oncology:
Positron Emission Tomography (PET) is useful for tumor detection, differentiation of benign and malignant disease, cancer staging and monitoring response to radiation or chemotherapy. PET is highly specific and sensitive in detecting certain tumors and metastatic disease, which can allow for the most appropriate treatment for the patient. Whole body PET can improve the staging of cancer at the time of diagnosis and scans can rule out distant metastases. Clinicians can monitor the patient’s response to therapy with PET and changes can be made to the patient’s treatment regimen if necessary. PET helps lower cost for some patients by altering patient management, for example, by eliminating unnecessary surgical procedures. Medicare/Medicaid has approved PET for the diagnosis, staging, and restaging of lung cancer, lymphoma, colorectal cancer, melanoma, esophageal cancer, head and neck cancer, brain tumors, and breast cancer.
Neurology:
PET has been shown to be very useful in patients with epilepsy. The areas of the brain affected by seizures can be identified. This helps in planning treatments and determining if the patient is a candidate for surgery. PET is also being used in the evaluation of dementia. For example, it can be used to help distinguish Alzheimer’s disease from other forms of dementia such as multi-infarct dementia. With PET, necrosis and scar tissue can be distinguished from recurrent brain tumors. Certain brain tumors, such as primary CNS lymphoma, can be distinguished from some types of infections such as toxoplasmosis, in immuno-compromised patients.
Cardiology:
PET is being used to evaluate myocardial metabolism and blood flow in patients with coronary artery disease. The scan can distinguish between viable and nonviable myocardium. The PET scan will help determine if the patient is a candidate for reperfusion via angioplasty or bypass surgery.