X-ray examination dose surveys: how accurate are my results?
To determine the variabilities of dose-area-products (DAP) of frequent X-ray examinations collected for comparison with diagnostic reference levels (DRLs).
DAP values of chest, abdomen, and lumbar spine examinations obtained on devices from two manufacturers were collected in three centers over 1 to 2 years. The variability of the average DAP results defined as the 95% confidence interval in percentage of their median value was calculated for increasing sample sizes, each examination and center. We computed the sample sizes yielding variabilities lower or equal to 25% and 10%. The effect of narrowing patient selection based on body weight was also investigated (ranges of 67–73 Kg, or 60–80 Kg).
DAP variabilities ranged from 75 to 170% of the median value when collecting small samples (10 to 20 DAP). To reduce this variability, larger samples are needed, collected over up to 2 years, regardless of the examination and center. A variability ≤ 10% could only be reached for chest X-rays, requiring up to 800 data. For the abdomen and lumbar spine, the lowest achievable variability was 25%, regardless of the body weight selection, requiring up to 400 data.
Variabilities in DAP collected through small samples of ten data as recommended by authorities are very high, but can be reduced down to 25% (abdomen and lumbar spine) or even 10% (chest) through a substantial increase in sample sizes. Our findings could assist radiologists and regulatory authorities in estimating the reliability of the data obtained when performing X-ray dose surveys.
• Low but reasonable variabilities cannot be reached with samples sized as recommended by regulatory authorities. Higher numbers of DAP values are required to reduce the variability.
• Variabilities of 10% for the chest and 25% for abdomen and lumbar spine examinations are achievable, provided large samples of data are collected over 1 year.
• Our results could help radiologists and authorities interpret X-rays dose surveys.
KeywordsRadiation protection Radiography Surveys and questionnaires
Automatic exposure control
Volume computed tomographic dose index
Dose area product
Diagnostic reference level
Entrance surface dose
The authors state that this work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Denis Tack.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
One of the authors has significant statistical expertise.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
• multicenter study
- 1.The council of the European Union (1997) Council Directive 97/43 of 30 June 1997 on Health protection of individuals against the dangers of ionizing radiation in relation to medical exposure, and repealing directive 84/466/Euratom. Available via http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:31997L0043. Accessed 19 Apr 2018
- 2.The Council of the European Union (2013) Council Directive 2013/59/EURATOM of 5 December 2013 laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation, and repealing Directives 89/618/Euratom, 90/641/Euratom, 96/29/Euratom, 97/43/Euratom and 2003/122/Euratom. Available via http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32013L0059&from=EN. Accessed 19 Apr 2018
- 3.European commission (1999) Radiation Protection 109: guidance on diagnostic reference levels for medical exposures. Available via https://ec.europa.eu/energy/sites/ener/files/documents/109_en.pdf. Accessed 19 Apr 2018
- 4.National Radiological Protection Board (NRPB) (2002) Doses to Patients from Medical X-ray Examinations in the UK – 2000 Review. Availabe via https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/405115/2002_NrpbW14.pdf. Accessed 19 Apr 2018
- 7.Advisory Committee on Radiological Protection (1997) Radiation Doses from Medical Diagnostic Procedures in Canada. Available via http://www.nuclearsafety.gc.ca/eng/about/past/timeline-dev/resources/documents/infohistorical/info-0670-E.pdf. Accessed 19 Apr 2018
- 8.Health Protection Agency – Centre for Radiation, Chemical and Environmental Hazards Radiation Protection Division (2007) Doses to Patients from Radiographic and Fluoroscopic X-ray Imaging Procedures in the UK – 2005 Review. Available via https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/431134/HPA-RPD-029.pdf. Accessed 19 Apr 2018
- 9.European commission (2008) Radiation Protection N°154: European Guidance on Estimating Population Doses from Medical X-Ray Procedures. Available via http://www.ddmed.eu/_media/background_of_ddm1:rp154.pdf. Accessed 19 Apr 2018
- 12.American Association of Physicists in Medicine (2011) Size-specific dose estimates (SSDE) in pediatric and adult body CT examinations. Task Group 204. College Park, Md: American Association of Physicists in MedicineGoogle Scholar