Lumbar spine radiographs — is it time for widespread adoption of posteroanterior projection?

Abstract

Objective:Phantom studies and a prior patient study have shown up to 53% effective dose reduction when lumbar spine radiographs are acquired posteroanterior (PA) instead of anteroposterior (AP). Since November 2017, Taunton and Somerset NHS Foundation Trust has acquired all standing lumbar spine radiographs PA. The aim of this study was to locally evaluate dose and image quality in both projections and survey current UK practice.Methods:80 outpatients having a standing lumbar spine radiograph (40 AP; 40 PA) had their dose–area product recorded at a constant KV and focus film distance. Effective dose was calculated using PCXMC software. Each blinded radiograph was scored against an optimal reference image using European Guidelines criteria. The data were analyzed using Mann–Whitney U tests and linear regression. Eighty radiologists nationally were sent an anonymous survey to establish their current practice.Results:A lumbar spine radiograph acquired PA instead of AP reduced effective dose by 41% (p < 0.001) with no difference in image quality (p = 0.9). 21 radiologists completed our survey and only 1 NHS Trust is currently using PA.Conclusion:PA lumbar spine radiography reduces patient radiation exposure with no affect on image quality, acquisition time or cost. The majority of NHS Trusts nationally are still using AP and it is time to standardize to PA.Advances in knowledge:This patient study provides further good evidence of how reduction in exposure to ionizing radiation can be achieved in lumbar spine radiography and more widespread adoption of PA protocol could improve patient safety.