Quality Control Assessment of Conventional Radiology Devices in Iran

Quality control (QC) techniques are used in monitoring and maintenance of the components of an x-ray system. QC of radiology devices plays a significant role in reduction of medication dose and optimization of image quality. This study aimed to conduct QC tests on randomly selected radiology devices, installed in diagnostic imaging departments of Iran.
In total, quality control tests were conducted on 51 conventional radiology devices installed in 20 cities of Iran in order to assess the accuracy of peak kilovoltage (kVp), exposure time, exposure linearity and reciprocity, reproducibility of exposure and determination of half-value layer (HVL) using a calibrated Mult-O-Meter.
In this study, 38.6% of devices had intolerable variance of kVp accuracy. The results of 34.5% of devices were out of the acceptable limits in exposure time accuracy test. In 46.7% and 53.1% of devices, variance was greater than the acceptable range for exposure linearity and exposure reciprocity, respectively. In terms of reproducibility of exposure test, the reproducibility variance and percentage of tube output variations in 19.4% of devices exceeded the limits. Moreover, the thickness of first HVL was lower than the acceptable limit in 14.7% of devices.
According to the results of this study, there were wide variations in QC test results, perhaps mainly due to the fact that it is not an obligation to implement QC programs in Iran. The most important problems were non-reciprocity of exposure, nonlinearity of exposure with milliampere-second (mAs), kVp and timer inaccuracy. Involvement of medical physicists, radiologists and radiographers in the implementation of QC programs at various stages of development, installation and use of equipment should enable the gradual improvement in equipment performance.