Throat cancer, PET scan tomorrow to see if it's spread

Hi all I have just been diagnosed with throat cancer I have to have a pet scan tomorrow full body to see if any cancer anywhere else I was told I need my tonsils out and radiotherapy although consultants said my tonsils looked healthy so don't understand the reason for removing them to do biopsy I had a raised lymph node in neck which was only symptoms really not looking forward too tonsillectomy's