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Abstract

Objective: To induce a reduction in dose, using a paediatric phantom, through the variation of exposure parameters and filtration, without adversely affecting image quality. Methods: All images were acquired using a Kyoto Kagaku paediatric phantom and a Canon DR detector. The phantom was positioned supine for all projections: wrist (DP, lateral) and ribs (AP, oblique). Three dose protocols were established using different mAs values (high, medium and low) and copper (Cu) filtration was added to each protocol. DAP was used to calculate the ESD for each exposure. Using ImageJ, CNR was calculated for the physical measurement of image quality. Image quality was assessed by fifteen observers (visual grading analysis (VGA)). Results: The highest doses were recorded with the high dose protocol, ranging from 5.60-39.22μGy for the wrist and 5.33-129.67μGy for the ribs. When increasing the Cu filtration a decrease in ESD was observed. A difference of 0.1 in VGA score was noted between high and low dose protocols without the use of filtration, while a difference of 0.3 was noted when using filtration. As mAs increased, VGA scores increased. Fracture visibility was minimally affected by Cu filtration or projection variation. Conclusion: The variation of exposure parameters in digital radiography can achieve a dose reduction without impairing image quality in bone fractures. Superior image quality can be achieved for DP and lateral wrist projections without Cu filtration. However, the addition of Cu filtration for the rib projections has almost no impact on overall image quality.

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