Optimisation in general radiography

Abstract

Radiography using film has been an established method for imaging the internal organs of the body for over 100 years. Surveys carried out during the 1980s identified a wide range in patient doses showing that there was scope for dosage reduction in many hospitals. This paper discusses factors that need to be considered in optimising the performance of radiographic equipment. The most important factor is choice of the screen/film combination, and the preparation of automatic exposure control devices to suit its characteristics. Tube potential determines the photon energies in the X-ray beam, with the selection involving a compromise between image contrast and the dose to the patient. Allied to this is the choice of anti-scatter grid, as a high grid ratio effectively removes the larger component of scatter when using higher tube potentials. However, a high grid ratio attenuates the X-ray beam more heavily. Decisions about grids and use of low attenuation components are particularly important for paediatric radiography, which uses lower energy X-ray beams. Another factor which can reduce patient dose is the use of copper filtration to remove more low-energy X-rays. Regular surveys of patient dose and comparisons with diagnostic reference levels that provide a guide representing good practice enable units for which doses are higher to be identified. Causes can then be investigated and changes implemented to address any shortfalls. Application of these methods has led to a gradual reduction in doses in many countries.

Optimization of image quality and patient dose in radiographs of paediatric extremities using direct digital radiography

“…The ideal set of parameters to describe IQ should measure the effectiveness with which an image can be used for its intended purpose. 24 The general scoring framework set out in this study follows the European guidelines although the IQ criteria have been set on the specific diagnostic requirements of paediatric extremity imaging, as defined by the clinicians at ELCH. As discussed previously, the primary issue with the IQ of the radiographs using the default parameters is the difficulty in differentiating between the cortexes of the tibia and surrounding soft tissue.…”

AP versus PA positioning in lumbar spine computed radiography: Image quality and individual organ doses

“…One simple but effective method of radiation dose reduction is the replacement of the traditionally performed anteroposterior (AP) projection with the posteroanterior (PA) projection. Martin (2007), in a recent review of the literature, found evidence that PA projections are often favoured over an AP projection on occasions where radiosensitive organs are lying closest to the anterior surface of the body (2). Despite this it is still common practice for the majority of UK departments to perform lumbar spine examinations using the AP position.…”

Evaluation of Image Quality of Plain Abdominal Radiographs at University of Maiduguri Teaching Hospital, North-Eastern Nigeria.

“…Studies of image quality are essential for optimization of the radiography processes in any clinical settings [5]. Guidelines have been set up by the European Commission (EC) for assessing the basic aspects of quality for clinical radiographic images dependent on techniques and imaging performance [3]. Generally, high image quality provides maximum information, improve the chance for correct diagnosis and ultimately contribute to quality patient care.…”

“…It is more important that the observer interpret the image appropriately than whether the appearance of the image is pleasing to the eye. The ideal set of parameters to describe image quality should measure the effectiveness with which an image can be used for its intended purpose [3].…”