Pet Scans

Does anyone know about how large a node has to be to "light up" on a PET Scan? I have a 5mm node that nobody is sure if it's scar tissue or another tumor (either recurrent or new primary). I was told to take a watch, wait and see action cause it's too small to light up on a PET. I can't pin any of my doctors down, nobody wants to really say anything. So, if anyone can relate, and has any idea of how large it has to be before it lights up, I'd appreciate any info (and I won't hold you to your opinion :-} I just would like ideas). Thanks.

Hi Alisa,
I am not sure how large a nodule or lesion has to be in order to be picked up by a PET. I have always understood that PET measures metabolic activity in the body. I don't know all the technical jargon,but the tracer that is injected contains glucose. Cancer cells uptake or hold onto the tracer and it shows up as activity on PET. I have always been told that PET can pick up smaller lesions than CT. It is my understanding that CT shows structures(such as the ability to measure the size of a tumor). I would ask more questions of your physician. My oncologist is often reluctant to use PET. His philosophy is that they aren't great diagnostic tools. Well I disagree with that. CT scans showed "stable lesions in my lungs" PET revealed numerous lesions!! I would not avoid CT it does have its place. I found a radiology site which explains different tests. It is www.radiology.org If you don't get through please post again. I would definitely ask more questions of the doctors. My onclolgist took me off chemo because I had no "measurable disease"...now I am stage IV. Good luck to you Julie C. Don't take what I say as the gospel truth as far as size of lesions...I am not an expert... I'd ask again if you are not satisfied with the doctor's responses.

ALISA,
I AM SORRY....I DID NOT GIVE YOU THE RIGHT ADDRESS FOR THE RADIOLOGY SITE. IT IS www.radiologyinfo.org/index.htm I hope you find it helpful. When you enter the site go to Diagnostic Radiology. It has several tests on there. I think the PET is under Nuclear Medicine...

Mom just had a PET Scan and we have to wait until Thursday for the doctor to give us the results.  We have a CD with the images but I have no clue what I'm looking at.  Would cancer show up as white or black spots on the scan?  I obviously had to look at the CD but not knowing what I am looking at just makes me speculate that everything I see on the image is more cancer.  Can anybody tell me what I should or should not be seeing on this scan.  Mom has stomach cancer and has been thru 2 rounds of chemo and had a complete gastrectomy.