Synthesized effective atomic numbers for commercially available dual-energy CT

Purpose The objective of this study was to assess synthesized effective atomic number (Z eff ) values with a new developed tissue characteristic phantom and contrast material of varying iodine concentrations using single-source fast kilovoltage switching dual-energy CT (DECT) scanner. Methods A newly developed multi energy tissue characterisation CT phantom and an acrylic phantom with various iodine concentrations of were scanned using single-source fast kilovoltage switching DECT (GE-DECT) scanner. The difference between the measured and theoretical values of Z eff were evaluated. Additionally, the difference and coefficient of variation (CV) values of the theoretical and measured values were compared with values obtained with the Canon-DECT scanner that was analysed in our previous study. Results The average Z eff difference in the Multi-energy phantom was within 4.5%. The average difference of the theoretical and measured Z eff values for the acrylic phantom with variation of iodine concentration was within 3.3%. Compared to the results for the single-source Canon-DECT scanner used in our previous study, the average difference and CV of the theoretical and measured Z eff values obtained with the GE-DECT scanner were markedly smaller. Conclusions The accuracy of the synthesized Z eff values with GE-DECT had a good agreement with the theoretical Z eff values for the Multi-Energy phantom. The GE-DECT could reduce the noise and the accuracy of the Z eff values than that with Canon-DECT for the varying iodine concentrations of contrast medium. Advances in knowledge The accuracy and precision of the Z eff values of the contrast medium with the GE-DECT could be sufficient with human equivalent materials.