Positron Emission Tomography / CT
Combines metabolic imaging with CT anatomy for cancer staging and therapy response.
What is PET-CT?
PET-CT injects a radiotracer (commonly FDG) to map metabolic activity, fused with CT for localization.
How it works: The tracer accumulates in metabolically active tissue; PET detects gamma photons and CT provides attenuation correction and anatomy.
Common Uses of PET-CT
Oncology staging/restaging
Detect nodal and distant metastases.
Therapy response
Measure metabolic response to chemo/immunotherapy.
Occult infection/inflammation
Identify fever of unknown origin or vasculitis.
Advantages
- ✓Whole-body survey of disease activity
- ✓Quantitative SUV metrics
- ✓Anatomical localization via CT
Limitations
- ⚠Higher cost and radiation dose
- ⚠False positives in inflammation
- ⚠Requires fasting and glucose control
Preparation & What to Expect
Before the Exam
Fast 4-6 hours; avoid strenuous exercise; check blood glucose.
During the Exam
Rest quietly during uptake period; limit speaking/muscle activity.
After the Exam
Hydrate well to clear tracer; limit close contact with infants for several hours.
Related Imaging Methods
CT or MRI may further characterize lesions; PET-MRI is an alternative in some centers.
CT
CT scans use X-rays to create detailed cross-sectional images of the body. They are particularly useful for detecting bone fractures, tumors, and internal bleeding.
MRI
MRI uses powerful magnets and radio waves to produce detailed images of organs and soft tissues. Excellent for brain, spine, and joint imaging.
Browse PET-CT Terms
Explore common findings and terminology in PET-CT reports. Each term includes detailed explanations, clinical significance, and related lab tests to help you understand your imaging results. lab tests.
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