Evaluation of exposure index and deviation index in general digital radiography

Abstract

Background: The Exposure index (EI) and Deviation index (DI) are key indicators for evaluating the appropriateness of radiation dose and the quality of radiographic images in digital radiography systems. Objective: to assess the distribution of EI and DI values ​​in general radiographic examinations of the chest, abdomen, pelvis, and lumbar spine using a digital radiography system. Methods: Patient data, technical exposure parameters, index values, and radiation dose information were retrospectively collected according to inclusion criteria from individuals who underwent general radiographic examinations with a Samsung digital radiography unit between October 2024 and February 2025. A total of 602 cases were analyzed using descriptive statistics. Results: The patients ranged in age from 16 to 93 years, with a higher proportion of females than males and body mass index (BMI) values ranging from 12.45 to 46.06. The majority of EI values across all examination sites were lower than the manufacturer’s target exposure index (EI_T). Most DI values were between –3 and -1, particularly in chest examinations, while a wider distribution of DI values was observed in abdominal, pelvis, and lumbar spine examinations. Conclusion: The EI and DI values in this study indicate radiation exposure outside the optimal range while still providing sufficient quality for clinical interpretation. Using the EI and DI values to assess deviations helps reflect the image quality, appropriateness of the imaging technique, and patient radiation safety