THE APPLICATION OF IMAGE QUALITY TEST OBJECTS IN SUPPORT OF CLINICAL X-RAY SERVICE - PHYSICAL AND TECHNICAL CONSIDERATIONS

The increasing technical sophistication and high capital cost of moder n radiological imaging systems is stimulating awareness in Diagnostic Radiology Departments of their need to implement quality management st rategies on their installed base of equipment. A comprehensive range o f scientific techniques and procedures required to assess X ray image quality and determine patient dose in the clinical department has evol ved over the preceding two decades and is now available for practical implementation. An important element of such procedures involves the p hysical assessment of X ray image quality using X ray test objects. Th ese devices represent a sensitive and reproducible means of testing sy stem imaging performance without recourse to irradiating live patients . The physical, technical and practical considerations in designing, m anufacturing and implementing X ray test objects and the evaluation of results derived while using them, are discussed. Various salient poin ts are illustrated with results obtained while routinely assessing con ventional and digital fluorographic imaging systems in clinical servic e. The relative merits of 'generic' and 'system-specific' designs of t est objects are discussed. The advantage of adopting a test object phi losophy which can be applied consistently across a number of different radiological imaging modalities is emphasised.