The effect of the introduction of picture archive and communication systems (PACS) on patient radiation doses and patient management
This thesis considers the effects of Picture Archive and Communications Systems (PACS), on both patient radiation doses and patient management. PACS is a relatively new technology which acquires, transmits, and stores radiological images digitally. This thesis investigates the doses which are required to produce radiographic images which are acceptable to radiologists and referring clinicians, and compares these doses with those required for the film/screen systems which they are replacing. A review of the literature shows that despite claims of dose reductions, very little good evidence exists about dose changes with the introduction of PACS. A comparison of images of test objects indicates that the images are comparable under limited conditions, that PACS has a much wider latitude than film (>250 mAs), and that contrast detail improves with increase in exposure. Two original observational studies are described in which PACS and film doses are compared for examinations of two groups of adult patients. The results indicate that the doses for PACS equate to those used with a 300 speed film/screen system thus necessitating dose increases of around 30% for the majority of adult patients in the UK. The issue of whether the number of images which are repeated, with additional patient doses, due to unsatisfactory images (rejected images), or unavailability of the images when clinically required (lost images), is addressed and indicates that PACS may allow a dose saving of 1.1 % and 1.4% respectively. The overall result of these studies indicates that the widespread introduction of PACS is likely to increase population doses. Two original studies which consider patients within the Accident and Emergency department are described. These studies aim to produce evidence to justify the introduction of the new technology, despite higher radiation doses, by identifying improvements in patient management which might improve patient outcomes. The results of these studies provide little evidence of such benefits to patients. This thesis concludes that the use of current PAC systems produces an increase in the radiation dose to the adult population in the UK, without demonstrable improvements in patient management.