When considering a single atom of Technetium 99m, or any other gamma emitter, does the emitted gamma ray have a vector? In other words, suppose it were possible to have just one molecule of Tc99m, and it were to decay in the middle of a room. Next suppose that two people with perfectly efficient detectors are standing on opposite sides of the molecule. If the gamma ray is emitted toward one detector, would the other detector observe the decay as well? What if the gamma ray were emitted orthogonally to each person/detector. Would either of them observe the gamma ray/photon? Now, suppose we consider a photoelectric event. If a NaI crystal scintillates from a single Thallium molecule, does that photon have a specific vector? Or does it radiate in a all directions in a probability wave?