Adult diagnostic reference levels in computed tomography: A systematic review and analysis of regional variability.
Abdel-Baset Bani Yaseen, Jamie Trapp, Davide Fontanarosa
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In 30 seconds
This systematic review examined adult computed tomography diagnostic reference levels (DRLs) across regions and examination types. A search of studies published from 2018 to 2025 identified 63 eligible studies; 48% reported local DRLs and 52% national DRLs. The review found substantial international variability. For head CT, reported CTDIvol values ranged from 38.2 to 117.6 mGy and dose-length product values from 512 to 1943 mGy·cm. The authors linked variation to differences in imaging practice, patient characteristics, technology, and methods used to establish DRLs.
Key findings
- Among 63 included studies, 48% reported local DRLs and 52% reported national DRLs.
- For head CT, CTDIvol ranged from 38.2 to 117.6 mGy across studies.
- For head CT, dose-length product ranged from 512 to 1943 mGy·cm.
- The 75th percentile was the most commonly used method for defining DRLs.
Why it matters
DRLs are benchmarks for reviewing and optimizing radiation doses, but substantial variation across regions and examination types limits straightforward comparison. Differences in protocols, patient characteristics, equipment, and DRL-setting methods may all contribute. More consistent methods and regular review could improve the comparability and usefulness of these benchmarks for CT dose optimization.
What to keep in mind
The review included only English-language studies published from 2018 to 2025, and the included studies used differing methods and reported substantial regional variability.