The aim in radiology is to obtain images which are adequate for the clinica
l purpose with the minimum radiation dose to the patient. If optimum perfor
mance is to be achieved, assessments of image quality must be made to balan
ce against patient dose. The subjective nature of image interpretation make
s an objective approach to such assessment difficult. Methods widely applie
d involve the use of test objects, which although providing a measure of im
aging performance may be difficult to link to clinical image formation. The
ideal method for evaluation of imaging techniques is through clinical tria
ls and this should be used to address major questions. Scoring of quality c
riteria, relating to features observed in a normal clinical radiograph, pro
vides a simple method through which image quality can be assessed in every
hospital department. (C) 1998 Elsevier Science Ltd. All rights reserved.