Long-Term Stability of Image Quality Measurements for Two Digital Mammography Systems
Contrast-detail measurements were made at approximately weekly intervals for three months, for two full-field mammography systems with different types of detector. The measured threshold contrast values were found to be reasonably stable but with some random variation. The coefficient of variance was 8-10% for detail sizes 0.1 and 1.0mm, and 3-5% for detail sizes 0.25 and 0.5mm. The output of both X-ray sets was also monitored, and found to vary within ±1% of the mean. The variation in threshold contrast is likely to be mainly due to variation of noise in the CDMAM images. Care should be taken when setting baselines and acceptable limits, so that measured changes in threshold contrast that are of the order of ±10% of the mean are not wrongly interpreted as significant changes in performance of a digital mammography system.
KeywordsImage quality threshold contrast CDMAM
Unable to display preview. Download preview PDF.
- 1.European Commission (EC): European Guidelines for Quality Assurance in Breast Cancer Screening and Diagnosis, 4th edn. Office for Official Publications of the European Communities, Luxembourg (2006)Google Scholar
- 2.Young, K.C., Alsager, A., Oduko, J.M., Bosmans, H., Verbrugge, B., Geertse, T., Van Engen, R.: Evaluation of software for reading images of the CDMAM test object to assess digital mammography systems. In: Proceedings of SPIE Medical Imaging, 69131C, 1–11 (2008)Google Scholar
- 3.Young K.C., Cook J.J.H., Oduko J.M., Bosmans H.: Comparison of software and human observers in reading images of the CDMAM test object to assess digital mammography systems. In: Proceedings of SPIE Medical Imaging, vol. 614206, pp. 1–13 (2006) Google Scholar
- 5.Yang, C.-Y.J., Van Metter, R.: The variability of software scoring of the CDMAM phantom associated with a limited number of images. In: Proceedings of SPIE Medical Imaging, 65100C (2007)Google Scholar