Hi Debs!
I can only speak for myself on this one...HPT did affect my thyroid but no nodules to my knowledge...It also gave me hypercalcemia, kidney stones, period weirdness, back and joint pain, gall stones, headaches, heartburn, and having to urinate every 25 minutes...Oh, gut trouble too...(I'm sure there was more that I've blissfully forgotten!).
The Sestamibi scan is no big deal. You have a prescan, (I didn't even have to get undressed!