obese the plate 23 does not need to be used in every case so it is easy to remove and just rests on top of the end members 20 the plate 23 is made of lexan or some other radio transparent material holes 22 are defined in the end members 20 for receiving fasteners in order to removably attach the plate 23 to the frame 14 the universal mounting structure 16 includes a pair of adjustable fixation legs 24 depending from opposed ends of each transversal end member 20 each fixation leg 24 includes a bracket 26 mounted for sliding movement in a vertically extending slot 28 each bracket 26 is provided with a set screw 30 such as a thumb screw for releasably securing the frame 14 to the longitudinally extending rails 32 fig2 normally provided at the sides of standard operating tables by adjusting the position of the brackets 26 in the slots 28 the frame 14 can be readily installed at various heights on the operating table 12 as shown in fig4 a the frame 14 provides enough clearance to permit the insertion and removal of a radiographic cassette c on the table 12 beneath the trunk of.