Which of the Following Statements Is Incorrect

Which of the following statements is incorrect?

A) Pacemakers for heart patients are powered by a plutonium-238 power device.
B) Iodine-131 is used for diagnosing thyroid tumors since iodine is preferentially absorbed by the thyroid gland.
C) Metastable technetium-99 is used for medical diagnosis because it is absorbed by tumor cells, but not normal brain cells.
D) Carbon-14 is used for PET imaging due to its long half-life and stability.
E) Gamma radiation from cobalt-60 is used to treat cancer patients.