METHODS FOR REDUCING DOSES TO PATIENTS FROM

X-RAY EXAMINATIONS

Radiological Procedures

1                    Define strict referral criteria to exclude clinically unhelpful examinations

2                    Improve availability of previously taken films and their transfer between hospitals

3                    Minimise number of radiographs per examination

4                    Minimise fluoroscopy time and current

5                    Introduce QA programme to make regular checks on and to optimise staff and equipment performance

6                    Regularly assess repeat rates and reasons for rejected and repeated films

7                    Periodically measure patient doses and take action if they exceed ‘guideline’ doses

8                    Collimate X-ray beam to minimise size

9                    Shield sensitive organs when possible

10                Choose projections which minimise dose to sensitive organs

11                Radiologists to specify a low mean optical density for radiographs

12                Use patient compression when appropriate

13                If radiographic exposure factors are selected manually, develop and employ reliable and accurate methods for matching them to patient stature

Radiology Equipment

14                Select the most sensitive film/screen combination available consistent with good diagnostic quality (e.g. rare-earth screens)

15                Operate film processor optimally (especially temperature)

16                Reduce attenuation between patient and image receptor to a minimum, e.g. use carbon fibre components in:

couch tops

antiscatter grids

cassette fronts

17                Improve the reliability and ease of use of AEC devices and use more widely

18                Use ‘Diamentor’ dose-area product meter to make regular checks on patient exposure and to monitor performance of those physically directing fluoroscopic examinations

19                Install antiscatter grids with lowest grid factors compatible with adequate scatter rejection

20                Remove antiscatter grid during fluoroscopy or photofluoroscopy when field size is small or detail not critical.

21                Use equipment with automatic beam collimation to image receptor

22                Develop X-ray generators that reliably deliver the low dose rates demanded by rare-earth screens and paediatric examinations

23                Install modern image intensifiers with sensitive (e.g. CsI) photocathodes and digital image processing

24                Use video recorder instead of cine camera during fluoroscopy wherever possible

25                Use spot film photofluoroscopy with modern image intensifier and 100mm camera instead of radiography whenever appropriate

26                Use pulsed systems with image storage devices in fluoroscopy

27                Use slot or scanned beam radiography

28                Replace conventional radiography by computed radiography

Ref: NRPB Patient Dose Reduction in Diagnostic Radiology, Vol 1 No 3 1990