Image reject analysis and rejection causes in digital radiography at a university hospital through estimates of patient doses.

ABSTRACT

The introduction of digital radiography has improved image acquisition. However, rejection of images remains a matter of concern. Reject analysis is part of the quality assurance program in radiology and helps identify potential errors or lack of training. A retrospective study was conducted at the radiology department of a university hospital. The reject rate was calculated both using the number of examinations, $r_n$, and the dose-area product, $r_d$. A reject rate $r_n$ of 3.3% for paediatric units and 4.5% for adults was found. The corresponding values of rd were 4.4 and 8.4%, respectively. The main rejection cause was patient motion, being 50.2% of rejected examinations in adults and 63.7% in children. The contribution of exposure errors was minor, as expected in digital radiography units. A discrepancy between reject rates $r_n$ and $r_d$ was observed, suggesting dosimetric quantities could be considered in reject analysis for further assessment of patient radiation burden.