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A 31-year-old member asked:

What is the difference between a cat scan and pet scan?

3 doctor answers8 doctors weighed in
Dr. Larry Wilf
35 years experience
Physiology: A ct scan is a static picture of anatomy. A pet/ct scan also shows you how metabolically active the " anatomy" is ...
Dr. Joseph Accurso
Radiology 30 years experience
Anatomy vs Physiolog: Ct scans look at the structure of the body, the anatomy, and the way diseases change or distort it. Pet looks at the physiology, or how the body uses, or metabolizes something. For pet, the most common metabolism pathway looked at is how glucose is used. A low dose ct is often acquired at the same time as the pet (as in pet/ct scan), to correlate the pet findings with the ct anatomy.
Dr. Gerald Mandell
Nuclear Medicine 53 years experience
Anatomy / metabolism: CAT scan utilizes xrays for determination of anatomical structures in multiple planes coronal, sagittal, and transaxial. PET scan uses radioactivity with tracer FDG 18 a glucose metabolite to show metabolic areas . Usually malignant lesions are most active. Small metastatic lesions can be detected. Sometimes compared with anatomy with PT CT.

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A 29-year-old member asked:

What shows up on pet scan but not on cat scan?

4 doctor answers9 doctors weighed in
Dr. Richard Bensinger
Ophthalmology 53 years experience
Cellular activity: A cat scan is a sophisticated computer driven x-ray image creator. It depends upon absorptive differences of static tissue and generates an image of the tissues in question. A pet scan depends upon the cellular activity of things like cancers, to pick up a radiolabeled sugar which is concentrated more in active tissue and is detected by the scan, generating a picture with a blob of activity.
Last updated Apr 5, 2018


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