Head Computed Tomography: Dose Output and Relationship with Anthropotechnical Parameters
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Abstract
Background: The number of computed tomography (CT) centers and examinations in Nigeria has shown a steady increase. This will
increase the collective dose and may potentially result in an increased incidence of cancer, hereditary diseases, and the possibility
of mild deterministic effects.
Objective: To determine radiation dose output and its relationship with anthropotechnical parameters.
Methodology: A retrospective analyses of digital CT files. Effective dose was derived from the dose‑length product and factor for
examination of head CT (0.0023 mSv/mGy‑cm). SPSS version 20.0 (SPSS Inc., Chicago, IL, USA) was used to analyze the data.
Results: Files of 43 male and 42 female (n = 85) adult patients were analyzed. The mean (and 75th percentile) of the CT dose index (CTDI), dose‑length product (DLP), and effective dose in noncontrast examinations were 48 (59) mGy, 874 (1301) mGy‑cm, and 1.8 (2.7) mSv, respectively. Contrast examinations yielded 54 (61) mGy, 1476 (2044) mGy‑cm, and 3.1 (4.3) mSv, respectively. DLP showed a weak relationship with BPD (r = −0.220), age (r = 0.211), cephalic index (r = −0.186), height (r = 0.158), and gantry tilt (r = 0.154). There was no relationship with weight (r = 0.076), range (r = −0.073), occipitofrontal diameter (r = 0.037), and body mass index (r = −0.018). The correlations were neither statistically nor clinically significant.
Conclusion: The CTDI is comparable with local values while the DLP is lower by a range of 5–31% but higher than foreign values by a range of 19–35%. Further optimization of CT radiation dose should be explored to eliminate the gulf between local and foreign dose outputs.
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