The aim of work: To develop a methodology to assess the quantum detection efficiency, and modulation transfer function for the X-ray detector, built by the scheme RLE - optics - PDCC-matrix. The methods: In paper describes a revised technique for evaluation of the detective quantum efficiency and modulation transfer function for X‑ray detectors of digital mammography systems SYMA and MADIS. The detectors are assembled according to the scheme: X-ray luminescent screen – lens – photosensitive CCD. The physical and technical conditions of generating input data sets for the evaluation program of parameters for mammography systems SYMA and MADIS and the principle of operation of the systems were considered. The results: The detailed description of input data obtained by receiving X-ray images via X-ray detectors was given. This quantity of information allows making calculations of investigated dependencies with sufficient accuracy. Stages of the program algorithm for calculating the values of the detective quantum efficiency and modulation transfer function of the detectors were described. The diagrams that show dependencies of the detective quantum efficiency and modulation transfer function on spatial frequencies which were received for X-ray detectors of commercially available samples of mammography systems SYMA and MADIS were given. The quality characteristics which were received satisfy the requirements of normative documents for the X-ray detectors. The conclusions: The method of estimating the quantum detection efficiency, and modulation transfer function for the X-ray detector, built by the scheme RLE - optics - PDCC matrix. Such detectors are used in the production of mammography complexes Madis and SIM is described. The quality characteristics of radiation detectors mammography complexes SYMA and MADIS performance meet the requirements of regulatory documents to the X-ray detectors.