Effects of various tilt angles on radiation dose and image quality in pediatric head computed tomography: A phantom study.

BACKGROUND

Various methods have been employed to reduce radiation dose and improve image quality in head computed tomography (CT); however, the impact of different head tilt angles on these factors remains underexplored.

OBJECTIVE

To investigate the effects of different head tilt angles on radiation dose and image quality in head CT.

MATERIALS AND

METHODS

A pediatric anthropomorphic head phantom was scanned using dual-source CT at 18 different tilt angles, repeated 10 times at each angle. Image quality was assessed using mean CT (CTmean) attenuation values and image noise at six regions of interest (ROIs), while radiation dose was evaluated using volume CT dose index (CTDIvol), size-specific dose estimate (SSDE), and dose-length product (DLP). The scan lengths of the eyes and head were also recorded.

RESULTS

CTDIvol and SSDE did not exhibit clear variation patterns with changes in head tilt angles, while DLP was in the lower region between -10° and 5°. Head scan lengths were relatively shorter between -10° and 5°, and eye scan lengths were relatively shorter between -10° and 0°. Except for the image noise of the right middle cranial fossa, no significant differences were found in CTmean values and image noise for the other ROIs between -10° and 0°.

CONCLUSION

The findings indicated that adjusting the head tilt angle within the range of -10° to 0° reduced both the head and eye scan lengths as well as the radiation dose, while preserving relatively stable image quality.