The potential for dose reduction in diagnostic radiology using low attenuation materials in table tops

It is important to be able to assign priorities to the purchase of radiological equipment. The ability to incorporate potential dose savings into a ranking procedure involving costs is therefore of interest. In this paper we have considered the question of the dose saving made available by the selection of low attenuation table tops and have described how to generate a factor which can be used in a ranking procedure such as cost effectiveness analysis. We describe how data on the expected dose saving can be obtained from measurements of the aluminium equivalent thickness in air used in conjunction with theoretical spectral data. The magnitude of the overestimate when in air measurements alone are used is presented, as is a ready reckoner for determining the true dose saving when changes in table top are considered. Unless the table to be replaced is of some age, the expected dose saving will vary between 6% and 1%.