Digital systems require x-ray charts too.
Eastman
T R
TR
Radiographic Techniques, Rocky Mount, Va., USA.
D006801:Humans; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods* / Q000592:standards; D013679:Technology, Radiologic / Q000295:instrumentation / Q000379:methods* / Q000592:standards