One of the most important steps in the optimization process in diagnostic imaging is the quality control (QC) of digital radiology devices. The defects of irradiation diagnostic devices in the framework of QC programs were assessed in imaging centers of Tehran province. To perform this schedule, various parameters such as kVp, milli-Ampere (mA), irradiation time, HVL, and additional filters were evaluated by three qualitative control tests. By using Pehamed phantom, Piranha dosimeter, and response time index, the QC of three radiological devices from three different companies—Samsung, Spellman, and Philips—was measured for the first time in Iran. The data obtained through the imagej software were analyzed. Different parameters including dynamic range, contrast, spatial resolution, beam quality, and homogeneity were compared from three devices. The HVL for Al was measured at 2.85 mm over the beam quality. Increasing the voltage increased the HVL so that the constant coefficients for PMX-III and a new electronic multimeter were 0.0787 and 0.0786, correspondingly. Also by raising dose, the irradiation index increased for different kVp and Al-HVL. The pixel values in different ROIs were assessed as there was no discrepancy at the center, but the greatest difference was emerged by 5.329 on the left. Of the pair of lead lines available in the phantom with size of 0.5–5 lp/mm at 45, 2.8 line pairs were completely separate to determine the resolution. Also, of the 16 copper sheets with thicknesses from 0 to 3.5, all sheets with thicknesses of 0.36 to 3.48 mm were visible. The coefficient of variation (CV) and the noise fluctuations were calculated for the adjusted voltage, irradiation time, and the output dose. At 100 mA, the maximum CV of the output dose was 0.0074 for 90 kVp-80 ms. The outcomes demonstrated that the Philips digital imaging system is of fairly good quality in all QC tests. Comparatively, the patient absorbed dose with the Spellman X-ray machine was less than with the other two devices. By recorded doses in assessment of linearity detector response, the Samsung and Philips machines demonstrated a great regression coefficient of 99% at different exposures. Improving quality control standards may improve diagnostic quality, reduce the number of repeated tests, and reduce patient exposure.