This episode of the Al Jazeera-produced People & Power series examines Iran's nuclear program.
At about 14:30 the argument is made that due to the short half-life of medical isotopes allegedly to be produced by a certain reactor its location doesn't match the official story since the materials are likely to "decay before you even get them to where you want."
I'd just like to point out that Canada - a country over 6 times larger than Iran - drew over 80% of its medical isotopes from the NRU reactor at Chalk River. Since that reactor's decomission, much of the supply has been shipped in from Europe and even as far away as South Africa.
I find this argument rather impotent when we are talking about a country which can be crossed by land in daylight.