A CT scan (Computed Tomography) and a PET scan (Positron Emission Tomography)
Published in Scanners and Imaging.
A CT scan (Computed Tomography) and a PET scan (Positron Emission Tomography) are both medical imaging techniques, but they work differently and serve distinct purposes.
1. CT Scan
- Uses X-rays to create detailed images of the body’s internal structures (bones, organs, soft tissues).
- Produces cross-sectional images that can be reconstructed into a 3D view.
- Mainly used to detect anatomical abnormalities such as fractures, tumors, infections, or bleeding.
- Can be performed with or without contrast dye for better visualization.
2. PET Scan
- Uses a radioactive tracer (usually a glucose-based substance labeled with fluorine-18) injected into the body.
- Detects metabolic activity in tissues and organs.
- Often combined with a CT scan (PET-CT scan) to pinpoint abnormalities more precisely.
- Mainly used in oncology (to detect cancer and metastases), neurology (Alzheimer’s diagnosis), and cardiology.
Key Differences
| Feature | CT Scan | PET Scan |
|---|---|---|
| Imaging Type | Anatomical | Functional (Metabolic) |
| Principle | X-rays | Injection of a radioactive tracer |
| Main Purpose | Detects tumors, fractures, bleeding | Detects cancer, neurological disorders, heart disease |
| Duration | Quick (a few minutes) | Longer (30-60 min) |
| Radiation Exposure | Yes (moderate) | Yes (low radioactive dose) |
In short, a CT scan provides detailed structural images, while a PET scan reveals how tissues function in real time. The two are often combined for more precise diagnosis.