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PURPOSE To investigate the clinical feasibility of noise, beam hardening artifacts(BHA) and radiation dose reduction of widedetector(8cm) cranial axial protocol compared with standard-detector(4cm) protocol and GSI monochromatic imaging. METHOD AND MATERIALS With local ethical committee approval, 150 subjects who performed head CT scan were enrolled in the study. 50 subjects were scanned on Revolution CT using wide-detector (8cm) axial protocol(120kVp, 260mAs), another 50 subjects were scanned on Discovery HD 750 CT using standard-detector(4cm) axial protocol(120kVp, 260mAs), the other 50 subjects were scanned using gemstone spectral imaging (fast switching of 80 and 140 kVp, 375mA with 0.7s rotation time) with 70 keV monochromatic image reconstructed. The background noise in corona and BHA in 4 different anatomic regions (oblongata, cerebellar, pons and the inferior part of frontal lobes) were measured and compared. Artifact index(AI) was defined as the square root of the squared noise difference between the region of interest and background. Data were analyzed by using One-way ANOVA test. RESULTS The image noise reduction and AI reduction of oblongata, cerebellar, pons and the inferior part of frontal lobes in widedetector polychromatic group were (12.83%, 19.03%), (24.42%, 33.39%),(16.64%, 24.14%) and (18.01%, 25.55%) ,values in GSI monochromatic (70keV) group were (18.45%, 26.22%),(32.26%,39.16%), (23.84%, 34.76%) and (33.97%,41.97%) compared with noise and AI in standard-detector polychromatic group, respectively. Both GSI and wide-detector groups showed significant lower noise and AI than that of standard-detector group(both of them P<0.05). There was no difference between GSI and widedetector group in AI (P>0.05). Compared with standard-detector group, the ED reduction was 17.37% in wide-detector group and 21.75% in GSI group, respectively. CONCLUSION The wide-detector polychromatic axial protocol and GSI monochromatic imaging protocol can significantly reduce image noise, BHA in cranial base and radiation dose were also decreased than standard-detector polychromatic axial protocol.