The monograph is devoted to the problems of creation of a broad complex of instruments for radiation monitoring and devices for non-destructive testing using the method of digital radiography. Data is presented on design principles of scintillator-photodiode type detectors, requirements to electronics for their application and principles of its construction. Practical uses of the instruments and devices are considered. New possibilities of digital radiography using original methods of multi-energy approach are presented, and advantages are shown of these systems made on the basis of scintillator-photodiode type detectors using an exclusive scintillator ZnSe(Te). For specialists in the field of scintillation materials. Can be useful for students of the related specialties.