my gyne said i had an enlarged thyroid and sent me for ultrasound, and pcp is testing my thyroid through blood (no results just yet) anmyway- the sonogram came back with lots of stuff wriiten on it, nodules that were exophatic, bolobed and HETEROGENEOUS amoung other things...and radiology report said a needle aspiration should be done BUT my PCP is sending me for this i123 scan instead/first? does this scan test for cancer?