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 Checklist
0 of 3 completed
⚖️PET-CT vs CT
Related Imaging Modalities
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.
Frequently Asked Questions
Find answers to common questions about this imaging modality.
Browse PET-CT Terms
Explore common terms in PET-CT reports, each with detailed explanations, clinical significance, and related lab tests to help you understand your imaging results. lab tests.
Colorectal Cancer PET-CT
FDG-avid primary tumor (SUVmax typically 5-15), metastatic lesions in liver/lungs/lymph nodes. Normal colon shows mild physiologic uptake, but focal intense uptake suggests malignancy.
Lung Cancer Staging on PET-CT
FDG-avid (hypermetabolic) lesions correlated with anatomic CT findings. Primary lung mass, lymph node involvement, distant metastases to liver, bone, adrenal glands, or brain.
Lymphoma PET-CT
FDG-avid lymphadenopathy with SUVmax typically 5-20 for Hodgkin lymphoma, 3-15 for NHL. Diffuse splenic uptake in splenic involvement. Bone marrow infiltration shows diffusely increased marrow activity.
Melanoma PET-CT
FDG-avid lesions with variable SUVmax (typically 2-10 for primary lesions, higher for metastases). Pattern includes primary skin lesion, in-transit metastases, lymph node involvement, and distant visceral metastases.
Petct Example 1
Representative finding for this modality.
Petct Example 2
Representative finding for this modality.
Petct Example 3
Representative finding for this modality.
Petct Example 4
Representative finding for this modality.
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