An investigation into the degree of difference in image quality between images taken on varying speed film-screen systems

Riggs, L.; Holmes, K.; Riggs, Louise; Holmes, Ken

Abstract

Purpose: Film-screen speed is one of the most critical factors affecting radiation dose to the patient, with faster speed systems requiring less radiation dose than slower speed systems for equivalent examinations. However, this is not without a cost, for accompanying this increase in speed, as well as a reduced patient dose, is a reduction in image quality. One must question whether this decrease in image quality is enough to be noticed by the human eye and, perhaps more importantly, whether it is enough to produce an image of undiagnostic quality. The aim of this research was to ascertain whether the increased radiation dose to the patient is really justified when using slower, more detailed intensifying screens, when perhaps the same diagnostic information could be achieved using faster film-screen systems with a decreased radiation dose. Methods: This investigation was mainly experimental in design and hence, the extraneous variables were carefully controlled. Identical density images of both a test tool and a hand phantom were evaluated subjectively under ideal viewing conditions by eight viewers, according to a specific set of criteria and a ranking scheme. Semi-quantitative evaluations of the test tool images were also carried out in order to facilitate the study. Results and Conclusions: Results from this research are tabulated and represented graphically. Friedman's two-way analysis of variance test and Wilcoxon's matched-pairs test are used to help analyse the data. The findings of this research would suggest that the same diagnostic information can often be produced with the faster speed systems as with the slower, more detailed intensifying screens. Therefore, opting for faster speed systems as a dose-reduction measure is certainly a feasible option. It was suggested that perhaps the best way of maximizing image quality and patient dose would be to choose film-screen speeds in accordance with pathologies under investigation. Despite the limitations of this research, which have been discussed in some depth, it has nevertheless highlighted the need for further study in this field. These findings would certainly support a large-scale study on this topic and it is hoped that this project would serve as a useful pilot to such an investigation. © 2001 The College of Radiographers.

• Journal Article Type: Article
• Publication Date: Jan 1, 2001
• Journal: Radiography
• Print ISSN: 1078-8174
• Electronic ISSN: 1532-2831
• Publisher: Elsevier
• Peer Reviewed: Not Peer Reviewed
• Volume: 7
• Issue: 1
• Pages: 65-75
• DOI: https://doi.org/10.1053/radi.2000.0300
• Keywords: film screen systems, difference in quality
• Public URL: https://uwe-repository.worktribe.com/output/1088188
• Publisher URL: http://dx.doi.org/10.1053/radi.2000.0300