Greyscale Appearance of Film‑screen Radiographic Artefacts in a University Teaching Hospital

Abstract

Objective: To link the greyscale appearance of radiographic artefacts with their origin, with a view to understanding and minimizing their occurrence.

Materials and Methods: A formula was used to establish a minimum sample size of 400 radiographs out of a population of 5500 radiographs produced between January 2013 and June, 2013. On a daily basis within the study period, all radiographs approved
for reporting by the quality control radiographer with over 10 years’ experience were scrutinized prospectively by the researchers with
the aid of a giant 100 cm × 50 cm viewing box with brightness adjustment, until 400 artefactual radiographs were eventually isolated.
The nature, greyscale appearance and origin of artefacts were arrived at by consensus and documented. Divergence in opinion and
ambiguous artefacts were resolved through observation of radiographers and darkroom assistants at work, as well as darkroom
simulations. The data on subdivision of artefacts was done using simple statistics.

Result: 400 radiographs out of a population of 5500 were sampled for the study. Twelve specific artefacts were isolated and categorized into three distinct appearances of black, white and grey. Preprocessing, processing and postprocessing were established as a broad classification for artefacts. Dispersed dots emanating from preprocessing (grey) and occurring in cassettes had the highest frequency of 140 (35%) while grid lines, n = 3 (0.8%) was the least noted.

Conclusion: All black artefacts arise during the preprocessing stage while processing and postprocessing have the middle-course greyscale appearance of artefacts.