That’s pretty damn creepy. Surprised I haven’t heard of this possible conspiracy theory before your post. Seems somewhat possible and/or believable.
Very possible that the truck had hospital radio active waste on it. This could be explanation on why airspace was shutdown for monitoring for 21 hours.
Check out these on Ghana
https://www-ns.iaea.org/downloads/rw/waste-safety/workshops/lisbon2010/wednesday/ghana.pdf
https://www-ns.iaea.org/downloads/rw/code-conduct/waste-code/presentations/tuesday/ghana.pdf