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.

Optimisation of Radiographic Procedures – Lumbar Spine Imaging in General Radiography

“…Papers describing optimisation techniques in lumbar spine radiography have been studied in several countries around the world. Those countries are Finland (16), Australia (17,34,39,41), Ireland (18,19,21,22,25), China (20), Sweden (24,26,33), Kuwait (23), United Kingdom (27,30,36), Slovenia (28,35,37), Iran (29,32), Israel (31), Croatia (38) and Malta (40).…”

“…The research methodology was experimental in almost all studies, except for three studies (16,32,39) in which the research methodology was a retrospective study of lumbar spine images. In most cases, the research was performed on an anthropomorphic phantom (17,20,34,41,(22)(23)(24)(25)(29)(30)(31)33), in a few studies the research was performed on patients only (27,(36)(37)(38), and some of them performed a combined study fi rst on a phantom and then on patients (18,19,21,26,28,35,40). The sample size of the examined patient studies varied from study to study.…”

“…The investigators studied the radiation dose to the patient and/ or phantom in all papers, but the measurement tool for the dose measurements varied from study to study. The dose was measured using TLDs (16,(18)(19)(20)(21)(22)25,28,33), ionization chambers (17,26,30), with some mathematical formulas and using conversion factors (21,23,32), DAP meters (27,35,36,38,40), based on calculations with the PCXMC program and Monte Carlo simulation (24,(29)(30)(31)(35)(36)(37)(38)41) and other ways (24,29,34). Image quality was not checked in a large number of the papers examined (17,20,34,37,(25)(26)(27)(28)(29)(31)(32)(33).…”

“…There were several ways to achieve dose optimisation in lumbar spine radiography. In 7 papers, the researchers used diff erent tube potentials (kV) (21)(22)(23)(24)34,39,41), diff erent mAs (41), in 5 papers they used alternative positioning of the patient, in which the patient or phantom was rotated to diff erent positions (19,27,(29)(30)(31)(35)(36)(37), and 2 studies used lead shielding as a method of radiation dose reduction (25,28). Four papers investigated increasing the distance (focus-fi lm distance and source-to-image distance) on the radiation dose to the patient during lumbar spine radiography (17,18,22,41), and some of the papers evaluate the eff ect of proper collimation (32,33,38).…”

“…Of the 26 reviewed papers, 14 (16,18,(38)(39)(40)(41)19,(21)(22)(23)(24)30,35,36) examined the eff ect of the optimisation procedure on image quality. In eleven papers, the researchers found no statistically signifi cant diff erence between image quality before and after optimisation (16,18,41,19,22,30,35,36,(38)(39)(40).…”