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Proceedings Paper

Quality Assurance in a National Breast Screening Study
Author(s): Martin J. Yaffe; Gordon E. Mawdsley; Robert M. Nishikawa
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Paper Abstract

In order to provide quality assurance for the National Breast Screening Study currently underway in Canada, a mailed survey package was designed which allows for the monitoring of i) the exposure for the "average" craniocaudad view, ii) beam quality, iii) speed, contrast, and fog parameters of the film processing, and iv) the overall image quality. As well, measurements were made of depth-dose curves to a breast phantom for a number of techniques so that mean glandular dose to the breast could be estimated from entrance exposures. To measure the duration of the x-ray exposure, a device which uses a photodiode to detect scattered radiation from the breast was designed and has been used to check consistency of phototiming and x-ray output. At one centre, the average skin exposure for the craniocaudad view was 295 mR. The range was 150 - 800 mR, due to differences in tissue density and distribution, breast thickness and compression. The mean glandular dose was estimated to be 66 mrad. For the intercomparison of imaging at the centres, identical lucite phantoms have been constructed and distributed which require an exposure time similar to that of the "average" breast. An aluminum step wedge built up of 15 sheets of 0.4mm Al is used to obtain "sensitometric" curves for the mailed survey. Some of the factors responsible for the variation in patient dose and image quality in the study are discussed.

Paper Details

Date Published: 13 December 1983
PDF: 8 pages
Proc. SPIE 0419, Application of Optical Instrumentation in Medicine XI, (13 December 1983); doi: 10.1117/12.936000
Show Author Affiliations
Martin J. Yaffe, University of Toronto (Canada)
Gordon E. Mawdsley, University of Toronto (Canada)
Robert M. Nishikawa, University of Toronto (Canada)


Published in SPIE Proceedings Vol. 0419:
Application of Optical Instrumentation in Medicine XI
Gary D. Fullerton, Editor(s)

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