Forss V, Yli-Ollila H, Vatanen J, Kölhi P, Poutanen VP, Palomäki A. The reliability of radiation dose display of a computed tomography scanner.
Eur J Radiol Open 2021;
8:100345. [PMID:
33898654 PMCID:
PMC8056233 DOI:
10.1016/j.ejro.2021.100345]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 11/30/2022] Open
Abstract
There is variation in the difference between the radiation dose reported by the CT scanner and actual measured dose.
This variation is substantial and may differ from zero.
To achieve more precise radiation dose data, especially in comparing studies, the average difference should be determined.
A correction factor for radiation dose should be utilized for every scanner used in studies.
Background
Internationally, the typical allowed difference between the measured radiation dose and dose reported by a computed tomography (CT) scanner is ±20 %. The objective is to describe a method in order to analyse this difference in a CT scanner in the Emergency Department of Kanta-Häme Central Hospital, and to calculate a correction factor for more comparable radiation dose values in further studies.
Methods
Ten intra-day radiation dose measurements were performed with undisturbed setting. Measurement reports on differences between measured and displayed dose were gathered from the vendor maintenance and supervising authority over a 12-year period. Additionally, two in-house measurements were made. A total of 18 datapoints were collected, with some differences in measurement settings. Data were also analysed against imaging parameters, ambient air pressure and time to identify trends or associations in the variation of the discrepancy.
Results
Measured doses were generally lower than displayed doses. Differences between displayed and measured doses varied between −3.46 and −0.10 %, with a mean of −1.26 % in the intra-day measurements, and between +4.65 and −17.3 %, with a mean of −7.53 % in the long-term data. There were no trends nor connections in the variations.
Conclusion
Since the acceptable difference between the radiation dose display and the measured dose is relevant, the average difference for every CT scanner should be determined before radiation dose studies, especially when comparing multiple scanners.
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