With ongoing technological improvements and research in the field of autonomous vehicles, it is becoming evident that the technology has the potential to substantially affect the transportation sector. Although the potential benefits with respect to productivity increases, cost decreases, and safety are evident, the potential for these vehicles to negatively or positively affect the transportation infrastructure is unclear. In this study, the influence of truck loadings positioning on the long-term performance of transportation infrastructure was estimated by carrying out performance simulations of pavement structures. Scenarios considering both full and partial use by autonomous trucks were considered. In all cases, performance was estimated with respect to rutting, fatigue cracking, and overall pavement smoothness, and the results were compiled in terms of reduced pavement thickness. It was found that if controlled appropriately, autonomous trucks could be highly beneficial for the pavement infrastructure design, and they would be most effective when they represented more than 50% of the total truck traffic. It was also found that in the absence of appropriate control, specifically by repeatedly positioning trucks in the same location, the amount of damage could be highly detrimental, and noticeable influences may occur at autonomous truck volumes as low as 10%.
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.
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