Determining the status of quality assurance, quality control and light beam diaphragm accuracy: A mixed methods survey of selected x-ray facilities in Lagos state

Abstract

Background: Lack of quality control (QC) programmes on X-ray machines contributes to image quality deterioration, film wastage and to increase in irradiation for patients and radiographers.
Aim: To assess the status of quality control/quality assurance and to determine the accuracy of light beam diaphragm (LBD) in X-ray facilities in Lagos state.
Methods: A mixed methods study design was used to determine QC tests being carried out on X-ray machines while LBD accuracy test was carried on Xray machines.
Results: In 50% of facilities studied, X-ray machines were ≥ 10 years old, < 10 years old in 1 facility while 1 center had an X-ray machine that is >30 years old after 1st installation. Although radiographers said that QC tests were performed in 70% of the centers, it was only in 40% of the centers that they reported the existence of a QA committee. Misalignment of LBD was >2.0% in most X-ray centers while lack of coincidence between the light and X-ray field increased significantly (p = 0.005) as the age of the Xray machine increased.
Conclusion: The status of QC/QA in X-ray facilities in Lagos state during the period studied was characterized by lack of understanding of the context, content and modus operandi of quality assurance in diagnostic radiography among many experienced radiographers. In particular, LBD was inaccurate in most X-ray facilities in Lagos state in the period studied. We found evidence in the present study to suggest that the practice of arbitrarily increasing the light field size by radiographers when there is LBD misalignment in order to offset the effect of anticipated mechanical cut-off appears to be counterproductive.

Keywords: Ionizing radiation, Light beam diaphragm accuracy; Quality control, Misalignment test