Uncertainty on Radiation Doses Estimated by Biological and Retrospective Physical Methods

Ainsbury, Elizabeth A.; Samaga, Daniel; Monaca, Sara Della; Marrale, Maurizio; Bassinet, C.; Burbidge, Christopher Ian; Correcher, V.; Discher, Michael; Eakins, Jonathan; Fattibene, P.; Güçlü, Incli; Higueras, Manuel; Lund, Eva; Maltar-Strmečki, Nadica; McKeever, S.W.S.; Rääf, Christopher; Sholom, S.; Veronese, I.; Wieser, A.; Woda, Clemens; Trompier, F.

doi:10.1093/rpd/ncx125

Cited by 33 publications

(18 citation statements)

References 104 publications

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“…The key sources can be identified in the paucity of human data and in the potential inter-individual variation (Suzuki et al 2002 ; Paquet et al 2016 ). Nevertheless, formal or even informal assessments, where information is lacking, are essential to ensure the quality and validity of the dose estimation techniques applied (Ainsbury et al 2014 , 2018 ).…”

Section: Discussionmentioning

confidence: 99%

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Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

Giussani

López

Romm

et al. 2020

Radiat Environ Biophys

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This work presents an overview of the applications of retrospective dosimetry techniques in case of incorporation of radionuclides. The fact that internal exposures are characterized by a spatially inhomogeneous irradiation of the body, which is potentially prolonged over large periods and variable over time, is particularly problematic for biological and electron paramagnetic resonance (EPR) dosimetry methods when compared with external exposures. The paper gives initially specific information about internal dosimetry methods, the most common cytogenetic techniques used in biological dosimetry and EPR dosimetry applied to tooth enamel. Based on real-case scenarios, dose estimates obtained from bioassay data as well as with biological and/or EPR dosimetry are compared and critically discussed. In most of the scenarios presented, concomitant external exposures were responsible for the greater portion of the received dose. As no assay is available which can discriminate between radiation of different types and different LETs on the basis of the type of damage induced, it is not possible to infer from these studies specific conclusions valid for incorporated radionuclides alone. The biological dosimetry assays and EPR techniques proved to be most applicable in cases when the radionuclides are almost homogeneously distributed in the body. No compelling evidence was obtained in other cases of extremely inhomogeneous distribution. Retrospective dosimetry needs to be optimized and further developed in order to be able to deal with real exposure cases, where a mixture of both external and internal exposures will be encountered most of the times.

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Section: Discussionmentioning

confidence: 99%

“…The current status of uncertainty assessment for general application of biological and physical retrospective dosimetry techniques has recently been reviewed (Ainsbury et al 2018 ), and thus this topic will not be considered in detail here.…”

Section: Retrospective Dosimetry Techniquesmentioning

confidence: 99%

Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

Giussani

López

Romm

et al. 2020

Radiat Environ Biophys

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“…Although originally an idea from chemical metrology (Currie 1999 , 2004 ), the terms critical dose, D CL , and dose limit of detection, D DL , have been used in the field of retrospective dosimetry (Ainsbury et al 2017 ). In the present study, D CL as well as D DL is calculated while taking the uncertainty of both the dose–response fit and the zero-dose signals into account.…”

Section: Methodsmentioning

confidence: 99%

Optically stimulated luminescence (OSL) dosimetry in irradiated alumina substrates from mobile phone resistors

Geber-Bergstrand

Bernhardsson

Christiansson

et al. 2017

Radiat Environ Biophys

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In this study the dosimetric properties of alumina (Al2O3) substrates found in resistors retrieved from mobile phones were investigated. Measurements of the decline of optically stimulated luminescence (OSL) generated following exposure of these substrates to ionising radiation showed that 16% of the signal could still be detected after 2 years (735 days). Further, the magnitude of the regenerative dose (calibration dose; D i) had no impact on the accuracy of dose estimates. Therefore, it is recommended that the D i be set as low as is practicable, so as to accelerate data retrieval. The critical dose, D CL, and dose limit of detection, D DL, taking into account the uncertainty in the dose–response relation as well as the uncertainty in the background signal, was estimated to be 7 and 13 mGy, respectively, 1 h after exposure. It is concluded that given the significant long-term component of fading, an absorbed dose of 0.5 Gy might still be detectable up to 6 years after the exposure. Thus, OSL from alumina substrates can be used for dosimetry for time periods far in excess of those previously thought.

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“…The quantification of uncertainties is a central part of dose reconstruction based on biological markers (IAEA 2011;Ainsbury et al 2018) and requires an appropriate experimental design, reasonable models, knowledge about the sources contributing to the uncertainty budget as well as assumptions on the underlying statistical distributions. Typically, for conventional manual scoring of dicentric chromosomes, the uncertainties resulting from the Poisson model for the calibration data are combined with uncertainties from the Poisson distributed test data (Merkle 1983;Savage and Papworth 2000;IAEA 2011;Higueras et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Improving the accuracy of dose estimates from automatically scored dicentric chromosomes by accounting for chromosome number

Endesfelder

Kulka

Einbeck

et al. 2020

International Journal of Radiation Biology

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Purpose: The traditional workflow for biological dosimetry based on manual scoring of dicentric chromosomes is very time consuming. Especially for large-scale scenarios or for low-dose exposures, high cell numbers have to be analyzed, requiring alternative scoring strategies. Semiautomatic scoring of dicentric chromosomes provides an opportunity to speed up the standard workflow of biological dosimetry. Due to automatic metaphase and chromosome detection, the number of counted chromosomes per metaphase is variable. This can potentially introduce overdispersion and statistical methods for conventional, manual scoring might not be applicable to data obtained by automatic scoring of dicentric chromosomes, potentially resulting in biased dose estimates and underestimated uncertainties. The identification of sources for overdispersion enables the development of methods appropriately accounting for increased dispersion levels. Materials and methods: Calibration curves based on in vitro irradiated (137-Cs; 0.44 Gy/min) blood from three healthy donors were analyzed for systematic overdispersion, especially at higher doses (>2 Gy) of low LET radiation. For each donor, 12 doses in the range of 0-6 Gy were scored semi-automatically. The effect of chromosome number as a potential cause for the observed overdispersion was assessed. Statistical methods based on interaction models accounting for the number of detected chromosomes were developed for the estimation of calibration curves, dose and corresponding uncertainties. The dose estimation was performed based on a Bayesian Markov-Chain-Monte-Carlo method, providing high flexibility regarding the implementation of priors, likelihood and the functional form of the association between predictors and dicentric counts. The proposed methods were validated by simulations based on cross-validation. Results: Increasing dose dependent overdispersion was observed for all three donors as well as considerable differences in dicentric counts between donors. Variations in the number of detected chromosomes between metaphases were identified as a major source for the observed overdispersion and the differences between donors. Persisting overdispersion beyond the contribution of chromosome number was modeled by a Negative Binomial distribution. Results from cross-validation suggested that the proposed statistical methods for dose estimation reduced bias in dose estimates, variability between dose estimates and improved the coverage of the estimated confidence intervals. However, the 95% confidence intervals were still slightly too permissive, suggesting additional unknown sources of apparent overdispersion. Conclusions: A major source for the observed overdispersion could be identified, and statistical methods accounting for overdispersion introduced by variations in the number of detected chromosomes were developed, enabling more robust dose estimation and quantification of uncertainties for semi-automatic counting of dicentric chromosomes.

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Uncertainty on Radiation Doses Estimated by Biological and Retrospective Physical Methods

Cited by 33 publications

References 104 publications

Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

Optically stimulated luminescence (OSL) dosimetry in irradiated alumina substrates from mobile phone resistors

Improving the accuracy of dose estimates from automatically scored dicentric chromosomes by accounting for chromosome number

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