An
uptake scan, which is what you had, does not do that. An ultrasound looks at the
thyroid inside and out, measures it, and detects any irregularities on the inside or the outside of the gland.
If any suspicious nodules or cysts are found, they are evaluated for the potential of being cancerous.
Your TG is low because the TGab is attacking the TG, which interferes with thyroid function.