Radioactive isotopes can be constituted-of-or-filled-with iodine.
Isotopes can be constituted-of-or-filled-with some elements.
Ratios can be constituted-of-or-filled-with (carbon isotopes).
Radioactive isotopes can be constituted-of-or-filled-with elements.
Physicists may disagree over (decay rates) of some isotopes.
Some isotopes can be constituted-of-or-filled-with elements.