A Standardised Approach to Optimisation

Abstract

PurPose: Optimisation of radiographic images is said to have been obtained if the patient has achieved an acceptable level of dose and the image is of diagnostic value. In the near future, it will probably be recommended that radiographers measure patient doses and compare them to reference levels. The aim of this paper is to describe a standardised approach to optimisation of radiographic examinations in a diagnostic imaging department. Method: A three-step approach is outlined with specific examples for some common examinations (chest, abdomen, pelvis and lumbar spine series).Step One: Patient doses are calculated.Step Two: Doses are compared to existing reference levels and the technique used compared to image quality criteria.Step Three: Appropriate action is taken if doses are above the reference level. results: Average entrance surface doses for two rooms were as follows AP Abdomen (6.3mGy and 3.4mGy); AP Lumbar Spine (6.4mGy and 4.1mGy) for AP Pelvis (4.8mGy and 2.6mGy) and PA chest (0.19mGy and 0.20mGy). Comparison with the Commission of the European Communities (CEC) recommended techniques identified large differences in the applied potential.The kVp values in this study were significantly lower (by up to 10kVp) than the CEC recommendations. discussion: The results of this study have indicated that there is a need to monitor radiation doses received by patients undergoing diagnostic radiography examinations. Not only has the assessment allowed valuable comparison with International Diagnostic Reference Levels and Radiography Good Practice but has demonstrated large variations in mean doses being delivered from different rooms of the same radiology department. Following the simple 3-step approach advocated in this paper should either provide evidence that department are practising the ALARA principle or assist in making suitable changes to current practice.

Can the anode heel effect be used to optimise radiation dose and image quality for AP pelvis radiography?

“…4,5 The search for an optimal approach that reduces patient dose whilst maintaining an image of diagnostic quality is a priority. 6,7 The latter can be implemented by identifying strategies which minimise the occurrence of patient overexposure, thereby reducing the probability of dose creep. 8 Manipulating primary exposure factors (tube potential (kVp) and tube load (mAs) [9][10][11] , varying the distance between X-ray tube and patients' skin 12,13 and the use of an air gap are approaches that have been used to optimise radiation dose and image quality for AP pelvis radiography.…”