Dose economy in radiodiagnosis. Present technical possibilities and development of normalisation

Some aspects of the contribution of technological progress to dose saving are examined first. For radiography on film a new generation of intensifying screens is now available, with rare earths incorporated either as new luminophores or as activators of the layer. This can increase the speed of the screens by a factor of more than 5. In practice a compromise must be found at values under 5 to avoid the appearance of quantic noise on the radiograph, but dividing the dose by two, three or four without deterioration of the image is already a very appreciable result. Moreover the use of the luminance amplifier tube offers an approach to photographic radiology techniques, remarkable for their small dose consumption. Finally such devices as automatic exposers, memory storage of parameters, anatomical programming are likely to avoid certain human errors leading to failed shots