Final answer:
The presence of high T4/T3, decreased TSH, and multiple hot nodules on a RAIU scan likely indicates a diagnosis of Toxic multinodular goiter, which is associated with hyperthyroidism and nodules autonomously producing excess thyroid hormone.
Step-by-step explanation:
The interpretation of a patient with high T4/T3 levels, decreased TSH, and multiple hot nodules on RAIU scan suggests the presence of a hyperthyroid condition. Among the options given, Toxic multinodular goiter is the most likely diagnosis. Graves' disease, another cause of hyperthyroidism, is usually associated with diffusely increased uptake on the RAIU scan and may present with Graves ophthalmopathy or goiter, but typically not with multiple hot nodules. Hashimoto's thyroiditis often leads to hypothyroidism, not hyperthyroidism, and would not typically present with multiple hot nodules or high T4/T3 with decreased TSH. Similarly, a thyroid adenoma is usually a single nodule rather than multiple and would not account for generalized thyroid overactivity. Hot nodules suggest areas of the thyroid that are producing excess thyroid hormone independently of TSH regulation, which is indicative of Toxic multinodular goiter.