They check all 4 during surgery to see if there bad. They take pics of each tumor they take out.

I also went to the norman clinic..............my parathyroid was hidden "behind" the thyroid and a standard scan would not have picked it up............Norman does a radioactive tracer.....check out the video on their web site.............and yes they did test them all. Norman will check your insurance...........I do have a supplement.
In average hospitals there is always the "management" which watches the financial bottom line and they just don't like to do fancy (expensive tests) so they just watch and wait. This is called "capitation" and yes despite all the cute little angels, hopitals are still a money making facility. Beckers is a good web site if you are interested in hospitals................