Effects of kilovoltage, milliampere seconds, and focal spot size on image quality

Purpose To determine how kilovoltage (kV), milliampere seconds (mAs), and focal spot size affect perceptual image qualityusing a hand phantom.Methods Using computed radiography, 70 images of a posteroanterior (PA) oblique hand phantom were acquired withdifferent kilovolt and milliampere second values using large and small focal spot sizes. Images were displayed on qualitycontrolledmonitors with dimmed ambient lighting. The look-up table for hand radiography was used for image display.Five diagnostic radiographers scored each image for perceptual image quality against a reference image using a 5-pointLikert scale.Results No significant difference in image quality was found between small and large focal spot sizes at different kilovolt(P = .46) and milliampere second (P = .56) values. As milliampere seconds increase, perceptual image quality increasesgradually from 0.4 mAs to 4 mAs, after which perceptual image quality begins to deteriorate. When kilovolts increase towithin the range of 40 kV to 55 kV, perceptual image quality increases; image quality remains stable after 55 kV.Discussion This study shows that both large and small focal spot sizes produce images of similar quality, and a widerange of kilovolt and milliampere seconds can be used to produce images of acceptable quality. The implications ofthese findings include the potential for extending the life of radiography equipment and the potential for reducing thedose patients receive during appendicular examinations.Conclusion Large focal spot size can be used for PA oblique hand imaging without affecting perceptual image quality.Perceptual image quality remains acceptable and stable for a wide range of kilovolt and milliampere second values.Optimizatio