"Exposing" the exposure index: Navigating between image quality and radiation dose.

Introduction: Deep knowledge of the properties and importance of the Exposure Index (EI) is crucial for delivering high-quality digital radiography images. This study aims to assess the EI on chest posterior anterior (PA) radiographic projection, demonstrating its correlation with parameters, such as body mass index (BMI), source-to-object distance (SOD), age, gender, and patient entrance skin dose (ESD).

Methods: The study population included 805 patients who underwent a routine PA chest projection. All data were collected on an Agfa imaging system. Height and weight were also measured, and BMI was calculated. Descriptive statistics was used for data analysis, and inferential statistics was used for correlation analysis between EI, gender, age, ESD and BMI.

Results: Over half (56.4%) of the study's participants were males; throughout the multivariate statistical correlation, increasing age was associated with increasing EI only in the female population (p=0.001). Ιn the lower BMI population subgroup, an increase in the SOD was associated with a decrease in the EI (p<0.001). Increasing BMI was associated with decreasing EI, while increasing ESD was linked to increased EI, except for those with lower or higher BMI, where no statistically significant relationship was observed (p=0.403 and p=0.445, respectively).

Conclusion: Analysis of the intercorrelation between important parameters such as the EI, BMI, ESD, SOD, age and gender can prove useful for radiographers, offering the ability to deliver high-quality diagnostic chest images, whilst also establishing the EI as an important and highly significant factor.