A D Gulson, T A Knapp and P G Ramsden
Publication date: 2007-06
The Dental X-ray Protection Service, DXPS, is part of the Radiation Protection Division of the Health Protection Agency, and is based at the Occupational Services Department in Leeds. DXPS has provided radiation protection advisory and technical services to dentists for over 30 years. Previous analyses of the results of routine patient dose measurements have provided data on the ranges of doses delivered during x-ray examinations in the UK, and allowed the derivation of third quartile dose values. A previous DXPS study, published in the British Dental Journal in 1999, recommended the adoption of reference doses, based on third quartile doses, for the two most common types of dental radiograph.
The most frequently undertaken dental x-ray examination is the intra oral radiograph. The reference dose for intra oral radiography recommended on the basis of the 1999 paper was 4 mGy, for an adult mandibular molar radiograph. The 1999 paper also recommended that the reference dose for panoramic radiography should be 65 mGy mm for a standard adult radiograph, and both these values were subsequently adopted as remedial levels in IPEM Report 77 and its recently updated version, IPEM Report 91.
Over the course of time, there has been a significant and continual reduction in patient dose for intra oral radiography, and this trend is evident in the data presented in this paper. The results of this study, which cover DXPS's results of x-ray set assessments over the calendar years 2002 to 2004, demonstrate that the third quartile dose for intra oral radiography has now fallen to 2.4 mGy. For panoramic radiography a much slighter reduction is apparent, with the third quartile dose now being 60 mGy mm. This paper examines the underlying causes for the above results and speculates on the scope for further dose reduction in the future.
Last reviewed: 29 July 2009