An apparatus for obtaining a radiographic image has a cassette with an erasable photostimulable storage medium, housed in the cassette, that can store a radiographic image when irradiated with electromagnetic radiation at an exposure wavelength and that can be erased for subsequent use when irradiated with electromagnetic radiation at an erasure wavelength. A memory that is associated with the cassette stores a signal that is indicative of elapsed time since the most recent erasure of the photostimulable medium.