Abstract: An X-ray cassette or a radiographic grid and X-ray cassette is (are) mounted within a device for positioning the cassette or grid and cassette beneath a patient lying upon a bed or other support to enable an X-ray image of a portion of the patient to be taken. The device has a plastics envelope formed of a material that is both substantially radiotranslucent and impervious to water or other biological fluids. This envelope defines first and second envelope sections separated from each other by a common edge. The first envelope section is generally rectangular in configuration and defines an openable pouch in which the X-ray cassette or radiographic grid and X-ray cassette are received. The second envelope section has a stiffening member therein. The second envelope section has its greatest width along the common edge and narrows to a minimum width at its edge furthest from the common edge.