PET Scans and Patient Information

Physicians diagnose, stage and track the progress of cancer with PET (positron emission tomography) scans. The two- to three-hour outpatient procedure causes little discomfort with the exception of one injection and the need to lay still for up to 45 minutes. Oncologists commonly recommend PET scans during a cancer treatment plan to evaluate the spread of cancer cells and the effectiveness of chemotherapy, radiation or other cancer treatments.

Procedure

• Before the procedure, the patient receives an injection of radioactive glucose solution. Depending on the type of cancer being evaluated, an inhalant or oral solution may replace an injection, according to the Mayo Clinic. The solution takes approximately one hour to circulate through the body. Next, the patient lays on a mobile table that slowly retracts into a scanning machine. The scan collects images of the internal organs and records their functions. Since cancer cells readily absorb glucose, the PET scan highlights these cells.

Effects

• The results of a PET scan help medical professionals determine the best course of cancer treatment for a patient. Since the scan identifies very small tumors and distant metastasis, treatment can begin quickly. Medical professionals also use the test to determine if newly found tumors are operable.

Benefits

• PET scans detect cancerous cells in soft tissue better than an X-ray-driven CT (computed tomography) scan, according to the American Cancer Society. Small cancerous cells that have absorbed the glucose solution show up more prominently in fat, muscle, lymph nodes and the digestive tract. A PET scan can also determine if a tumor is benign or malignant.

Drawbacks

• CT scans locate the exact position of cancerous tumors more accurately than PET scans. Some oncologists will order both a CT scan and PET scan for a more complete evaluation of the patient's condition. Doctors often restrict food, water and some medications for up to 12 hours before a PET scan. During a preparatory consultation, patients must disclose a complete list of current medications, vitamin and herbal supplements.

Additional Uses

• In additional to its popular uses in oncology, PET scans assist neurologists and cardiologists evaluating myocardial variability and medically refractory seizures. Physicians also use PET scans to monitor organ function, brain disorders, blood flow, oxygen use, central nervous functioning and glucose metabolism, according to the Cleveland Clinic, a nonprofit academic medical center in Ohio.