Evaluation of CT Image Quality Based on Signal-to-Noise Ratio in Axial and Helical Scanning Modes with Tube Current Variation

This study aims to evaluate computed tomography (CT) image quality based on the signal-to-noise ratio (SNR) parameter across two scanning modes: axial and helical. An anthropomorphic head phantom was scanned using a Siemens Healthineers Somatom go.Top CT system. The evaluation was conducted using tube current variations of 100 mAs, 200 mAs, and 300 mAs for each scanning mode. This approach was employed to investigate the influence of tube current variation on image quality and to identify the optimal parameter combination that yields the highest image quality. The results demonstrated a consistent increase in SNR with rising tube current for both scanning modes. However, the helical mode tended to produce higher SNR values compared to the axial mode at equivalent tube currents. These findings suggest that the helical mode is superior in producing better-quality images in terms of SNR. This study may serve as a reference for selecting technical imaging parameters to achieve optimal CT image quality. The conclusion indicates that the helical mode at 300 mAs provided the highest image quality, with the highest SNR value of 4.79 and the lowest noise level of 4.43 HU. Nonetheless, it should be noted that higher tube current also leads to increased radiation dose, thus clinical application should be tailored according to patient-specific needs.Keywords: CT scan, signal-to-noise ratio, image quality, axial mode, helical mode, tube current.