Effect of Tube Setting Variables on Image Quality in Industrial X-ray Computed Tomography

摘要

To investigate the effects of x ray tube setting on image quality in industrial computed tomography, an experimentalcharacterization with constant tube powers has been reported in this paper. A series of CT scans for a QRMMedium-Contrast-Phantom were performed with a constant tube power of 40W and other scanning parameters, varyingtube voltages from 80kV to 125kV and tube currents from 320μA to 500μA. The signal-to-noise ratio (SNR) andcontrast-to-noise ratio (CNR) measured on the reconstructed images indicated that increasing the tube voltage canimprove the SNR, as well as the CNR in high density areas. While in low density regions in the phantom, higher CNRresulted from lower voltage or higher tube current. Furthermore, a custom-made aluminum cylinder is scanned severaltimes for the assessment of the CT spatial resolution, similarly keeping a constant tube power and variable tube voltagesand currents. According to the obtained modulation transfer function (MTF)1/10 values, defined as the spatial frequencycorresponding to a contrast loss of 10 %, it is found that using the same tube power, the tube voltage has a greater impacton improving the CT spatial resolution.