The causes of reject images in a radiology department at a state hospital in Windhoek, Namibia

Charlene Benza, Christine N Damases-Kasi, Edwin Ralph Daniels, Mondjila Amkongo, Caroline Nabasenja


Purpose Reject film analysis (RFA) is a well-established method of quality assurance (QA) in diagnostic radiology that gives an indication of the sources of imaging errors and highlights areas where improvements can be made. Despite the adoption of computed radiography (CR) which has a wide dynamic range and image post-processing capabilities, radiographic images are still rejected thereby emphasising the role of regular RFA in any radiology department. Regular RFA can reduce radiation exposure to patients and personnel as well as decreasing departmental operational costs. Therefore, this study aimed to identify the causes of reject images and to calculate the rejection rates at a state radiology department in Windhoek, Namibia.

Methods Using a quantitative, explorative, non-experimental and descriptive research approach, reject images obtained over a two-month period were retrieved from the computer radiography system. The images were then assessed to identify the reasons for rejection; reject rates were calculated.

Results Of the 2258 images reviewed, 181 were reject images, resulting in an overall departmental reject rate of 8%. Positioning (63%), exposure (24.9%), gridlines (1.7%), collimation (2.2%), absence of anatomical markers (2.8%), and artefacts (5.5%), were identified as the causes for image rejection. Chest and skull radiographs had the highest reject rates of 48.1% and 9.9%, respectively.

Conclusion Positioning error was the highest contributor to reject images. Even though the overall reject rate in this study was within the IAEA 5-10% recommended range, reject rates associated with individual anatomical areas require further investigation.


reject film analysis, reject rate, X-ray images

Full Text:


The South African Radiographer | ISSN 0258 0241

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.5 South Africa License