Optimisation of direct digital chest radiography using Cu filtration

• 0.3 mm Cu filter reduced radiation dose by 37% without decline in image quality.
• A 5.8% decrease in effective dose observed with 0.3 mm filtration setting.
• 0.3 mm Cu provides optimum balance between image quality and dose.

PurposeTo assess the impact of additional Cu filtration with the DRX-1 detector in optimisation of adult chest radiography.MethodsA simulated anatomical phantom was imaged at different levels of Cu filtration (0 mm, 0.1 mm, 0.3 mm and 0.5 mm of Cu) at 120 kVp. Image quality was assessed using exposure index, conspicuity index, signal-to-noise ratio and pixel density. Dose area product (DAP) meter was used to measure dose; effective dose and risk of exposure induced cancer death (REID) were estimated using the PCXMC software 2.0.ResultsExposure index increased with increasing Cu thickness; 0.3 mm Cu filtration increased conspicuity index of simulated nodules, with a minimal decrease in signal-to-noise ratio, and pronounced decrease in pixel density. Patient doses were reduced by 20.7%, 36.6%, and 39.79% at 0.1 mm, 0.3 mm, and 0.5 mm levels of Cu filtration respectively.ConclusionAdditional beam filtration using 0.3 mm Cu filter with the DXR-1 detector reduced patient doses by 37% without decline in image quality.