Positron Emission Tomography (PET) Scan
This scan is good for determining metastasis with malignant tumors. It determines whether the tumor has spread to lymph nodes, or other areas of the body.
The PET scan will often light up some benign parotid tumors, such as a Warthin tumor, oncocytoma, and cellular pleomorphic adenoma, and gives the impression that these tumors may be malignant.
It is also not as useful to have a PET scan right after treatment, such as surgery or radiation, as it will light up all of the inflamed fields.