Pet Scan False Positives

I am 4th year out from breast cancer, had mastectomy and chemo, don't know why, but refused radiation. Think I was afraid of what it might do to my heart and margins were clear. About a year ago, started to notice that on either lower jaw I had some swelling, usually worse in the morning and my face also seemed to be swollen. Went to my oncologist who said my parotid glands were blocked and I should "suck a lemon". At that point, I changed oncologists. There also was swelling on the back of my neck, kind of like a hump which would resolve as the day wore on, he called that "just a fat pad", but, I knew it was more than that. However, since then I had been reluctant to bring anything up to oncology. Last month I caught a cold from a friend whose own symptoms resolved within 3 days. Mine continued for a week and had to finally go on antibiotics. Because of other symptoms my oncologist ordered a CT scan which showed a "nodule" and said to repeat the scan in 3 months..the scan was repeated and this time showed lymph nodes "suggestive of cancer". Next step was a PET scan which I had last WED. Today, I spoke to my oncologist who reported many "false positives", that the next step would be endoscopy and to have my primary check my skin since something showed up there. Has anyone else heard of false positives? How do they know a false positive from a positive? This is all very confusing and concerning. I don't get it. What's going on?

before the pet scan you are not suppose to move around for two days prior. kind of lay in bed and watch tv. because the pet scan will show any metabolic growth so if your using muscles it can show up as a false positive. I have now stage 4 breast cancer and had a pet scan which confirmed the mri and ct scan but it can show even more but if you have been active it will not be accurate. also sometimes other things like liver cysts will show up as a positive. when they are not. alot of doctors do not like to depend entirely on pet scans because of these issues.,
susan

Dear Sresthadasi,

My wife has been diagnosed with liver cancer based on a pet scan.  I see from your message that you said that liver cysts often show up as cysts and give a positive pet scan.  Can you tell me where I can get more information on pet scans/and false positives?  They want to remove 1/2 of her liver based on a pet scan.  If you could help I would really, really appreciate it.

Thanks

 

Wayne