How Important Is Nuclear Scan In Treating Enlarged Goitre?

I have an enlarged goitre with nodules, low tsh levels 0.13 T3 levels 5.3 t4 levels are 15.2 my antibodies test results are TG My doctor has sent me to a surgeon who wants me to have a nuclear scan then a biopsy (needle) then he wants to remove it . Wanting to now how important the nuclear scan is and would I be able to just have the needle biopsy and go from there for surgery or not, also do I have a autoimmune disease, my doctors have given me little explanation to any questions I had , also wanting to now how can I get my thyroid working properly by taking a natural approach if possible