Study of the relationship between radiation dose and image quality in computed tomography (CT)
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Date
2026
Authors
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Publisher
Faculty of Sciences
Abstract
The increasing use of computed tomography (CT) has raised growing concerns about
balancing radiation dose reduction with the preservation of diagnostic image quality. This
challenge is addressed through the As Low As Reasonably Achievable (ALARA) principle,
which advocates minimizing radiation exposure while maintaining sufficient image quality for
accurate diagnosis and patient safety.
This study aimed to investigate the relationship between radiation dose and image quality
in thoraco-abdomino-pelvic computed tomography (TAP CT) examinations performed during
the portal venous phase. In addition, the effects of demographic and technical factors, including
age, sex, and tube current-time product (mAs), on radiation dose and image quality were
evaluated.
The study was conducted at the Central Radiology Department of Ibn Rochd University
Hospital, Annaba, Algeria, using a SCENARIA View Whole Body X-ray CT System
(FUJIFILM Corporation, Japan). A total of 12 patients (6 males and 6 females) who underwent
TAP CT examinations were included. Radiation dose was assessed using the Computed
Tomography Dose Index volume (CTDIvol) and Dose-Length Product (DLP), while
objective image quality was evaluated using Noise, Signal-to-Noise Ratio (SNR), and
Contrast-to-Noise Ratio (CNR). CTDIvol values ranged from 6.4 to 8.9 mGy, whereas DLP
values ranged from 486.4 to 677.7 mGy·cm.
Linear regression analysis showed a weak association between age and radiation dose,
with coefficients of determination (R²) of 0.1403 for males and 0.1468 for females, indicating
that age explained only a small proportion of the variability in radiation dose within the study
population. In contrast, a strong positive correlation was observed between mAs and CTDIvol,
with R² = 0.9135 for males and R² = 0.9879 for females, confirming the expected increase in
radiation dose with increasing tube current-time product.
The relationship between radiation dose and image quality varied according to the
evaluated metric. For Noise, the coefficients of determination were 0.8769 in males and 0.2639
in females. For SNR, the corresponding values were 0.5911 and 0.5752, while CNR showed
R² values of 0.6222 and 0.3710 for males and females, respectively. These findings suggest that
image quality is influenced not only by radiation dose but also by technical acquisition
parameters and patient-related characteristics.
Overall, the results demonstrate that optimizing CT protocols requires consideration of
multiple factors beyond radiation dose alone. Appropriate selection of acquisition parameters
can improve diagnostic image quality while minimizing radiation exposure in accordance with
Abstract
the ALARA principle. Nevertheless, the relatively small sample size warrants further studies
involving larger patient populations to strengthen the statistical power and improve the
generalizability of the findings