Quality assurance of viewing boxes: proposal for establishing minimum requirements and results from a Spanish quality control programme

Abstract

The Medical Physics Group at the Complutense University of Madrid has undertaken a project, during the last 3 years, under a CEC contract on “Optimization of Radiation Protection in Diagnostic Radiology” (Vañó, 1989) in which a pilot programme of Quality Control (QC) was included (Gonzalez, 1989). Exhaustive patient and occupational dose measurements showed differences between the test results from similar equipment. This fact moved us to set up a Quality Control Programme (Guibelalde & Llorca, 1989), and then several Quality Assurance (QA) programmes. The necessity to establish minimum performance requirements for image quality, and the convenience of denning objective parameters to make possible further advances in the reduction of patient doses and optimization of image quality, has been pointed out at several Workshops of the Commission of European Communities (CEC) on Image Quality in Diagnostic Radiology. A Working Document of the CEC (1989) has recently been issued emphasizing the need to develop appropriate quality criteria. The aim of these activities is to produce standards and quality criteria that will provide a framework, throughout the European Community, for producing images with minimum patient dose and maximum quality. Efforts to ensure the best quality and consistency of viewing boxes must aid these objectives. The brightness and uniformity of viewing boxes are two factors that can be measured in absolute units. These factors are not influenced by other elements of image quality control and, therefore, can be used for comparisons between different centres.