A survey of local diagnostic reference levels for the head, thorax, abdomen and pelvis computed tomography in Norway and Canada.
Acta Radiol Open 2022;
11:20584601221131477. [PMID:
36225897 PMCID:
PMC9549116 DOI:
10.1177/20584601221131477]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/22/2022] [Indexed: 11/05/2022] Open
Abstract
Background
Computed tomography (CT) contributes to 60% of the collective dose in medical
imaging. Literature has demonstrated that patient dose varies across regions
and countries. Establishing diagnostic reference levels (DRLs) contributes
to the optimization of clinical practices and radiation protection.
Purpose
To survey the dose indices (CTDIvol and dose-length product) for frequently
performed CT examinations from the chosen hospitals in Norway and Canada and
to determine local DRLs (LDRLs) based on the collected data.
Material and Methods
The survey included eight scanners from two Norwegian hospitals and four
scanners from four Canadian hospitals. Dosimetry data were collected for the
following routine CT examinations: head, contrast-enhanced thorax, and
abdomen and pelvis. Overall 480 adult average-sized patients from Norway and
360 from Canada were included in the survey. The LDRLs were determined as
the 75th percentile of distributions of median values of dose indicators
from different CT scanners. The differences in dose between scanners were
determined using single-factor ANOVA.
Results
The LDRLs determined in Norway were higher overall than in Canada. The
obtained values were compared to the national DRLs. The dose from several
scanners in Norway exceeded national Norwegian DRLs, while Canadian LDRLs
were below the Canadian reference levels. The differences between the means
of the dose distributions from each scanner were statistically significant
(p < 0.05) for all examinations with exception of
identical scanners located in the same hospital and using the same
protocols.
Conclusion
Observed dose variations even in the same hospital, or from the same scanner
model confirmed the need for CT protocol optimization.
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