Had CT to check arteries in lungs. 3mm nodule found. Intern. Med. Doctor said normal, no worry. Pulmonary said scan in 12mo. I need any more radiation?

That depends..... If you are/were a smoker, yes, worth the repeat radiation. If you are concerned about lung cancer, and did not want any more radiation, any doctor that uses HDL (health diagnostic labs) labs can draw blood and run a lung cancer antibody profile. It has very high sensitivity, and is very specific towards antibodies the body produces against lung cancers. Not a smoker, try the blood test.
Follow the pulmonary. 3mm nodule does not need any treatment but to be on the safe side repeat cat scan in 1 year to see if the nodule has got bigger in side or any other changes the fear of radiation has to be taken in context of your medical condition and if you don't do cat scan it may miss if the nodule has increased in size or character and that is important. We do not want to second guess the pulmonologist.