Optimisation of direct digital chest radiography using Cu filtration

Purpose: To assess the impact of additional Cu filtration with the DRX-1 detector in optimisation of adult chest radiography. Methods: A simulated anatomical phantom was imaged at different levels of Cu filtration (0mm, 0.1mm, 0.3mm and 0.5mm of Cu) at 120kVp. 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. Results: Exposure index increased with increasing Cu thickness; 0.3mm 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 0.1mm, 0.3mm, and 0.5mm levels of Cu filtration respectively. Conclusion: Additional beam filtration using 0.3mm Cu filter with the DXR-1 detector reduced patient doses by 37% without decline in image quality.