# Balancing Radiation Dose and Image Quality: Protocol Optimization for Mobile Head CT in Neurointensive Care Unit Patients

## TL;DR

This study shows that reducing radiation dose in mobile CT scans for neurointensive care patients does not affect image quality, making it safer for patients.

## Contribution

The study introduces a low-dose protocol for mobile head CT that reduces radiation exposure without compromising diagnostic quality.

## Key findings

- Low-dose CT protocol reduced radiation exposure by 28.7% compared to the default protocol.
- Quantitative image quality parameters remained unchanged between the two protocols.
- Qualitative image quality was rated as excellent by neuroradiologists.

## Abstract

Objective: Mobile head CT enables bedside neuroimaging in critically ill patients, reducing risks associated with intrahospital transport. Despite increasing clinical use, evidence on dose optimization for mobile CT systems remains limited. This study evaluated whether an optimized CT protocol can reduce radiation exposure without compromising diagnostic image quality in neurointensive care unit patients. Methods: In this retrospective single-center study, twenty-two non-contrast head CT examinations were acquired with a second-generation mobile CT scanner between March and May 2023. Patients underwent either a default (group A, n = 14; volumetric computed tomography dose index (CTDIvol) 44.1 mGy) or low-dose CT protocol (group B, n = 8; CTDIvol 32.1 mGy). Regarding dosimetry analysis, we recorded dose length product (DLP) and effective dose (ED). Quantitative image quality was assessed by manually placing ROIs at the basal ganglia and cerebellar levels to determine signal, noise, signal-to-noise ratio, and contrast-to-noise ratio. Two neuroradiologists independently rated qualitative image quality using a four-point Likert scale. Statistical comparisons were performed using a significance threshold of 0.05. Results: Median DLP and ED were significantly lower for group B (592 mGy·cm, 1.12 mSv) than for group A (826 mGy·cm, 1.57 mSv; each p < 0.0001). Quantitative image quality parameters did not differ significantly between groups (p > 0.05). Qualitative image quality was rated excellent (median score 4). Conclusions: The optimized mobile head CT protocol achieved a 28.7% reduction in radiation exposure while maintaining high diagnostic image quality. These findings support the adoption of low-dose strategies in mobile CT imaging in line with established radiation protection standards.