I see an Endocrinologist and he sets it up with the hospital and interventional radiology to have my biopsies and then my PEI done. Hope this helps.
One who is trained in being able to understand the ultrasound image as well as usually being specialist. It is highly advised an ultrasound is done as a guide to the needle going into the nodule.
I had mine done by a endocrinologist, but a ENT (ears, nose, and throat) doctor could also do this. My primary thyroid doctor is a endocrinologist, my surgeon is a ENT specialist.