Get the picture? Iran can't get isotopes from Canada, but the USA can; the distance makes the difference. Iran can neither import medical isotopes from overseas nor participate in a world-wide export market, simply because there is no such market precisely because the very nature of medical isotopes do not allow it. Sheesh.
Police on scene of shooting at Savannah State University campus in Georgia (Reuters)
from the article: Iran installs advanced centrifuges at Natanz to speed up nuclear work