Evaluation of the Influence of Exposure Index on Image Quality and Radiation Dose

Introduction: The introduction of digital radiography has led to a significant problem in terms of dose creep. To address this problem, manufacturers have established a set of exposure indicators (EI) as a feedback mechanism to safeguard against overexposure. The EI is the measure of incident exposure to the detector that is directly proportional to the signal-to-noise ratio and can be related to image quality. The aim of this study was to evaluate the influence of EI on image quality and radiation dose for the posterior anterior (PA) chest radiography. Material and Methods: This study was conducted in three phases, namely pre-optimization, experimental, and post-optimization. A total of 60 patients that could fulfill the inclusion and exclusion criteria for the PA chest radiography were recruited. The radiographic technical parameters, dose area product, and EI were recorded. Radiographs were printed and evaluated by two recruited radiologists using the modified evaluation criteria established by the Commission of European Communities in 1996. Results: Statistical analysis using Spearman’s Rho Correlation showed an insignificant relationship between EI and image quality for the PA chest radiography (P>0.05). Conversely, there was a significant relationship between EI and radiation dose (P<0.05). Conclusion: The EI can be used as an indirect measure of image quality and radiation dose. The EI does not directly determine image quality since the radiographic technique and parameters used can affect image quality. Although EI can be used as a measure of radiation dose, it cannot provide an accurate measurement of the radiation received by the patient.