PET Scan

A PET (Positron Emission Tomography) scan is a type of imaging test that uses a radioactive tracer to visualize the metabolic activity of cells in the body.

How it Works

The PET scan works by injecting a small amount of a radioactive tracer, usually a sugar molecule called fluorodeoxyglucose (FDG), into the bloodstream. The tracer accumulates in areas of high metabolic activity, such as cancer cells, which use more glucose than normal cells.

Types of PET Scans

• Oncology PET scan: used to diagnose and monitor cancer, including detecting tumors, metastases, and recurrence
• Neurology PET scan: used to evaluate brain function, diagnose neurodegenerative diseases such as Alzheimer's and Parkinson's, and detect seizures
• Cardiology PET scan: used to assess heart function, detect coronary artery disease, and evaluate the effectiveness of cardiac treatments

Preparation for a PET Scan

To prepare for a PET scan, patients are typically asked to:

• Fast for at least 4-6 hours before the scan
• Avoid strenuous exercise and caffeine for 24 hours before the scan
• Remove any metal objects, such as jewelry or glasses
• Change into a hospital gown

Procedure

The PET scan procedure typically involves:

• Injection of the radioactive tracer into a vein in the arm
• A waiting period of 30-60 minutes to allow the tracer to accumulate in the body
• Lying on a table that slides into the PET scanner, which is a large, doughnut-shaped machine
• The scan itself, which can take anywhere from 15-90 minutes, depending on the type of scan and the area being imaged

Risks and Side Effects

PET scans are generally safe, but may involve some risks and side effects, including:

• Exposure to small amounts of radiation
• Allergic reactions to the tracer
• Discomfort or anxiety during the scan

Results

The results of a PET scan are typically interpreted by a radiologist, who will look for areas of high metabolic activity that may indicate disease. The results can be used to:

• Diagnose and stage cancer
• Monitor the effectiveness of treatment
• Detect recurrence or metastasis

Combination with Other Imaging Tests

PET scans are often combined with other imaging tests, such as:

• CT (Computed Tomography) scan: provides detailed anatomical information
• MRI (Magnetic Resonance Imaging) scan: provides detailed images of soft tissues and organs

Advantages and Limitations

PET scans have several advantages, including:

• High sensitivity for detecting cancer and other diseases
• Ability to provide functional information about cellular activity
• Non-invasive and relatively painless

However, PET scans also have some limitations, including:

• Exposure to radiation
• High cost
• Limited availability in some areas