Possible recurrance

I was diagnosed with Stage IIIa non-small cell lung cancer in 9/03. I underwent chemo which shrunk the tumor by more than 1/2. 12/03 had a portion of my lung removed. Then three more rounds of chemo. Have been cancer-free since 2/04. My routine CT last week showed something "suspicious" so I'm scheduled for a PET scan Mon. This area in my lung has shown for quite a while and they assumed in was soft tissue, scarring from my surgery. But in comparing it to my CT in Jan. it has now grown, measuring a little less than 2". My oncologist said that if the PET scan shows something (a medical word I did not understand) then he would want my surgeon to take a piece of it. I am, of course, quite worried. I'm also a little confused. First time around they told me for sure I had cancer when I had the first CT. Following that they did a needle biopsy. Also PET scan, MRI, bone scan to check other areas of my body. I don't understand now why the CT alone doesn't tell them whether or not it's cancer. I also wonder why a surgeon would need to "take a piece" of it when the last time they just did the needle biopsy. I have the PET scan tomorrow and see the oncologist TUes. so guess I'll have answers soon. But 2 days away can sound like a very long time when you are worried! Any info or similar experiences from anyone out there?