Dentomaxillofacial Radiology, Vol 24, Issue 2 132-134, Copyright © 1995 by British Institute of Radiology

ARTICLES

Artefacts due to static electricity in a dental school

I. P. Sewerin
Department of Radiology, School of Dentistry, Faculty of Health Science, University of Copenhagen, Denmark.

The diagnostic usefulness of radiographs is diminished by errors of film handling, and retakes mean increased radiation doses. Avoiding artefacts due to static electricity is part of a quality assurance programme. The number of types of artefacts originating from static electricity in the Department of Radiology, School of Dentistry, Copenhagen, were recorded over a five-week period with low temperatures and low air humidity. During the period 3137 intra-oral and 638 extra-oral films were processed by seven assistants and a number of trainees. A total of 48 artefacts on 47 extra-oral films was observed. The artefacts were classified into four types. Only one case of classical 'lightning' was found, while nine were of a hitherto undescribed type ('animals' or 'cactus flowers'). The most common type appeared as dots arranged in straight lines; their origin was obscure, but it was suspected that they were caused by the processing machine. The one typical 'lightning' case occurred on a Status-X film, consistent with the theory that friction may be a causative factor. Although individual frequencies varied, all the radiography assistants and trainees were associated with the artefacts recorded.