The present invention provides a positioning system comprising at least a portable detector that enables users to continuously know the spatial location of a detector relative to an x-ray source so that it can be more easily aligned, and monitored for maintenance of alignment, with the portable detector within predetermined tolerances during procedures. In preferred embodiments, the invention further comprises a radiation interlock switch to prevent the emission of radiation in the event of the x-ray source and detector not being aligned within a predetermine tolerance.
