Evaluation of mAs Linearity, kVp Accuracy, and Reproducibility in Selected X-ray Diagnostic Facilities in Freetown

Quality control in medical radiology is a process used by a regulatory authority to evaluate the performance of a diagnostic X-ray machine, including acceptable limits and the actions necessary to meet regulatory requirements. This study evaluates the radiation dose outputs of X-ray equipment in diagnostic medical hospitals by measuring mAs linearity, kVp accuracy, and reproducibility as quality control parameters to ensure that radiation doses administered to patients meet standard regulatory requirements. Radiation measuring instruments were used in this work to measure mAs, kVp accuracy, and reproducibility outputs for five (5) medical diagnostic X-ray machines. The detector was placed on the couch at a distance of 100 cm from the collimator to take measurements for each parameter under investigation. Dose rate measurements for each parameter were recorded one at a time. The mathematical equations for mAs linearity, kVp accuracy, and reproducibility were used to compute the linearity coefficient, percentage error, and coefficient of variation. The computed figures for mAs linearity for the five X-ray machines show that four (4) passed and one fell below the allowable limit. Data for kVp accuracy indicate that three of the machines are within the allowable limits and two (2) failed, while the calculated values for reproducibility show that only two (2) machines passed the tests. The study generates empirical quality control data rarely reported in X-ray diagnostic centers. It verifies the linearity coefficient, percentage kVp error, and the coefficient of variation with practical knowledge in radiology studies. Additionally, it provides a systematic mathematical approach to compute mAs linearity, kVp accuracy, and reproducibility for teaching radiology in non-diagnostic laboratory settings.