need for a PET SCan

I recently found out I had a single nodule just under 1cm in size in my upper left lung via a CT. My doctor wants to wait for 2 months to repeat the CT scan. As a 58-yr-old who has worked in a hydrocarbon processing environment for 30 years, I think that my odds aren't very good. I asked why he would not do a PET/CT scan, and he said the spot wasn't big enough. I then asked if it could have metastasized from another location in the body, and wouldn't the PET/CT scan point that out, and his only answer was that I didn't have any symptoms to indicate that. Is this good advice, and am I just being paranoid about it, or should I go elsewhere?