scholarly journals ICRP recommendations on radon

2020 ◽  
Vol 49 (1_suppl) ◽  
pp. 68-76 ◽  
Author(s):  
J.D. Harrison ◽  
J.W. Marsh

The International Commission on Radiological Protection (ICRP) publishes guidance on protection from radon in homes and workplaces, and dose coefficients for use in assessments of exposure for protection purposes. ICRP Publication 126 recommends an upper reference level for exposures in homes and workplaces of 300 Bq m−3. In general, protection can be optimised using measurements of air concentrations directly, without considering radiation doses. However, dose estimates are required for workers when radon is considered as an occupational exposure (e.g. in mines), and for higher exposures in other workplaces (e.g. offices) when the reference level is exceeded persistently. ICRP Publication 137 recommends a dose coefficient of 3 mSv per mJ h m−3 (approximately 10 mSv per working level month) for most circumstances of exposure in workplaces, equivalent to 6.7 nSv per Bq h m−3 using an equilibrium factor of 0.4. Using this dose coefficient, annual exposure of workers to 300 Bq m−3 corresponds to 4 mSv. For comparison, using the same coefficient for exposures in homes, 300 Bq m−3 corresponds to 14 mSv. If circumstances of occupational exposure warrant more detailed consideration and reliable alternative data are available, site-specific doses can be assessed using methodology provided in ICRP Publication 137.

2019 ◽  
Vol 184 (3-4) ◽  
pp. 298-301 ◽  
Author(s):  
S B Solomon

Abstract Exposure to radon in show caves is an existing exposure situation. A survey of radon levels in underground show caves around Australia, carried out in 1994, found that most of the show caves located in South-Eastern Australia had yearly average radon levels exceeding the Australian radon reference level of 1000 Bq m−3. At the time of the original survey, the radiation doses from exposure to radon progeny of the tour guides in these caves were estimated using the epidemiologically based dose conversion factors and all dose were assessed to be less than 10 mSv per year. In February 2018, the International Commission for Radiological Protection (ICRP) published updated radon and radon progeny dose conversion factors (DCF) applicable to worker exposure to radon in show caves. These updated DCF values are based on dosimetric modelling and are sensitive to the radon progeny activity size distribution. The recommended DCF values are up to a factor four times higher than the previous ICRP recommendations. The ICRP has published data that allows for the estimation of site-specific radon progeny dose coefficients if required. A reassessment of the radiation doses to workers in Australian show caves has been made using these updated ICRP DCF values and the historical measurements of radon progeny activity size distributions in Australian show caves. Using the site-specific DCF values, it is estimated that 15% of the workers exceeded 10 mSv y−1 and 6% exceeded 20 mSv y−1. Although the total number of show cave workers in Australia is very small, the updated radon progeny dose estimates are a significant radiation protection issue for the affected individuals and their employers.


Author(s):  
Richard Wayne Leggett ◽  
Caleigh Samuels

Abstract The ICRP recently updated its biokinetic models for workers in a series of reports called the OIR (Occupational Intakes of Radionuclides) series. A new biokinetic model for astatine, the heaviest member of the halogen family, was adopted in OIR Part 5 (ICRP Publication 151, in press). This paper provides an overview of available biokinetic data for astatine; describes the basis for the ICRP’s updated model for astatine; and tabulates dose coefficients for intravenous injection of each of the two longest lived and most important astatine isotopes, 211At and 210At. Astatine-211 (T1/2 = 7.214 h) is a promising radionuclide for use in targeted α-particle therapy due to several favorable properties including its half-life and the absence of progeny that could deliver significant radiation doses outside the region of α-particle therapy. Astatine-210 (T1/2 = 8.1 h) is an impurity generated in the production of 211At in a cyclotron and represents a potential radiation hazard via its long-lived progeny 210Po (T1/2 = 138 d). Tissue dose coefficients for injected 210At and 211At based on the updated model are shown to differ considerably from values based on the ICRP’s previous model for astatine, particularly for the thyroid, stomach wall, salivary glands, lungs, spleen, and kidneys.


2020 ◽  
Vol 191 (1) ◽  
pp. 39-120
Author(s):  
Scott O Schwahn ◽  
Caleigh E Samuels ◽  
Richard W Leggett

Abstract Inhalation and ingestion dose coefficients for the embryo and fetus from intakes of radionuclides by the mother are provided in the International Commission on Radiological Protection (ICRP) Publication 88 for intake of each of 74 radionuclides. To address the many other possible radionuclides to which workers may be exposed, effective dose coefficients were developed for the embryo/fetus for all additional radionuclides addressed in ICRP Publication 107 with half-life of 10 min or more. The general approach was to use the estimated dose to the mother’s uterus during pregnancy as a scalable proxy for the dose to the embryo/fetus. The set of scaling factors used in the study was derived from analyses of the relationships of the dose to the mother’s uterus and the effective dose to the embryo/fetus for the ~400 cases (considering two intake modes and multiple forms of many of the radionuclides) addressed in Publication 88.


2020 ◽  
Vol 191 (2) ◽  
pp. 188-191
Author(s):  
Petr P S Otahal ◽  
Ivo Burian ◽  
Eliska Fialova ◽  
Josef Vosahlik

Abstract Measurements of activity concentration of radon gas and radon decay products were carried out in several workplaces including schools, radium spas, swimming pools, water treatment plants, caves and former mines. Based on these measurements, annual effective doses to workers were estimated and values of the equilibrium factor, F, were calculated. This paper describes the different approaches used to estimate the annual effective dose based on the dose coefficients recommended by the International Commission on Radiological Protection. Using the measured F values as opposed to the default F value of 0.4 changed the doses by about 5–95% depending mainly upon the ventilation conditions of the workplace.


2018 ◽  
Vol 47 (3-4) ◽  
pp. 63-74 ◽  
Author(s):  
F. Paquet ◽  
J. Harrison

Internal doses are calculated using biokinetic and dosimetric models. These models describe the behaviour of the radionuclides after ingestion, inhalation, and absorption to the blood, and the absorption of the energy resulting from their nuclear transformations. The International Commission on Radiological Protection (ICRP) develops such models and applies them to provide dose coefficients and bioassay functions for the calculation of equivalent or effective dose from knowledge of intakes and/or measurements of activity in bioassay samples. Over the past few years, ICRP has devoted a considerable amount of effort to the revision and improvement of models to make them more physiologically realistic representations of uptake and retention in organs and tissues, and of excretion. Provision of new biokinetic models, dose coefficients, monitoring methods, and bioassay data is the responsibility of Committee 2 and its task groups. Three publications in a series of documents replacing the ICRP Publication 30 series and ICRP Publications 54, 68, and 78 have been issued [Occupational Intakes of Radionuclides (OIR) Parts 1–3]. OIR Part 1 describes the assessment of internal occupational exposure to radionuclides, biokinetic and dosimetric models, methods of individual and workplace monitoring, and general aspects of retrospective dose assessment. OIR Parts 2–5 provide data on individual elements and their radioisotopes. Work is also in progress on revision of dose coefficients for radionuclide intakes by members of the public.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsuyoshi Masuda ◽  
Toshitada Yoshioka

AbstractRadiation doses from organically bound tritium (OBT) in foods have been a major concern near nuclear facilities. The current dose coefficient for OBT is calculated using a standard model from the International Commission on Radiological Protection, in which some biokinetic values are not based on human metabolic data. Here, the biokinetics of ingested OBT, and radiation doses from them, were estimated by administering labelled compounds and foods to volunteers, using a deuterium (D) tracer as a substitute for tritium. After the administration of D-labelled glucose, alanine, palmitic acid, or soybean, the D/H ratios in urine were measured for up to 119 days, and the biokinetic parameter values were determined for OBT metabolism. The slow degradation rates of OBT could not be obtained, in many volunteers administered glucose and alanine. The estimated committed effective dose for 1 Bq of tritium in palmitic acid varied from 3.2 × 10–11 to 3.5 × 10–10 Sv Bq−1 among volunteers and, for those administered soybean, it varied from 1.9 × 10–11 to 1.8 × 10–10 Sv Bq−1. These results suggest that OBT, present in some ingested ingredients, gives higher doses than the current dose coefficient value of 4.2 × 10–11 Sv Bq−1.


2018 ◽  
Vol 47 (3-4) ◽  
pp. 35-44 ◽  
Author(s):  
M. Zankl ◽  
J. Becker ◽  
C. Lee ◽  
W.E. Bolch ◽  
Y.S. Yeom ◽  
...  

Phantoms simulating the human body play a central role in radiation dosimetry. The first computational body phantoms were based upon mathematical expressions describing idealised body organs. With the advent of more powerful computers in the 1980s, voxel phantoms have been developed. Being based on three-dimensional images of individuals, they offer a more realistic anatomy. Hence, the International Commission on Radiological Protection (ICRP) decided to construct voxel phantoms representative of the adult Reference Male and Reference Female for the update of organ dose coefficients. Further work on phantom development has focused on phantoms that combine the realism of patient-based voxel phantoms with the flexibility of mathematical phantoms, so-called ‘boundary representation’ (BREP) phantoms. This phantom type has been chosen for the ICRP family of paediatric reference phantoms. Due to the limited voxel resolution of the adult reference computational phantoms, smaller tissues, such as the lens of the eye, skin, and micron-thick target tissues in the respiratory and alimentary tract regions, could not be segmented properly. In this context, ICRP Committee 2 initiated a research project with the goal of producing replicas of the ICRP Publication 110 phantoms in polygon mesh format, including all source and target regions, even those with micron resolution. BREP phantoms of the fetus and the pregnant female at various stages of gestation complete the phantoms available for radiation protection computations.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Vera Höllriegl ◽  
Nina Petoussi-Henss ◽  
Kerstin Hürkamp ◽  
Juan Camilo Ocampo Ramos ◽  
Wei Bo Li

Abstract Purpose Ra-223 dichloride (223Ra, Xofigo®) is used for treatment of patients suffering from castration-resistant metastatic prostate cancer. The objective of this work was to apply the most recent biokinetic model for radium and its progeny to show their radiopharmacokinetic behaviour. Organ absorbed doses after intravenous injection of 223Ra were estimated and compared to clinical data and data of an earlier modelling study. Methods The most recent systemic biokinetic model of 223Ra and its progeny, developed by the International Commission on Radiological Protection (ICRP), as well as the ICRP human alimentary tract model were applied for the radiopharmacokinetic modelling of Xofigo® biodistribution in patients after bolus administration. Independent kinetics were assumed for the progeny of 223Ra. The time activity curves for 223Ra were modelled and the time integrated activity coefficients, $$ \overset{\sim }{a}\left({r}_S,{T}_D\right), $$ a ~ r S T D , in the source regions for each progeny were determined. For estimating the organ absorbed doses, the Specific Absorbed Fractions (SAF) and dosimetric framework of ICRP were used together with the aforementioned $$ \overset{\sim }{a}\left({r}_S,{T}_D\right) $$ a ~ r S T D values. Results The distribution of 223Ra after injection showed a rapid plasma clearance and a low urinary excretion. Main elimination was via faeces. Bone retention was found to be about 30% at 4 h post-injection. Similar tendencies were observed in clinical trials of other authors. The highest absorbed dose coefficients were found for bone endosteum, liver and red marrow, followed by kidneys and colon. Conclusion The biokinetic modelling of 223Ra and its progeny may help to predict their distributions in patients after administration of Xofigo®. The organ dose coefficients of this work showed some variation to the values reported from clinical studies and an earlier compartmental modelling study. The dose to the bone endosteum was found to be lower by a factor of ca. 3 than previously estimated.


Author(s):  
Martin Ian Ralph ◽  
Marcus Cattani

Abstract In the 2019-20 reporting period, nineteen mining operations in Western Australia were identified as having workers who were likely to be exposed to ionising radiation stemming from naturally occurring radioactive materials (NORMs), seventeen of which, known hereinafter as Reporting Entities (REs), were required to submit an annual report of the dose estimates of their workforce to the mining regulatory authority. In 2018 the International Commission for Radiological Protection published the revision of the Dose Coefficients (DCs) for occupational intakes of radionuclides of the uranium-238 and thorium-232 decay series, in ICRP-137 and ICRP-141. The 2019-20 annual reports are the first to apply the revised DCs to estimate worker doses. The mean effective dose (ED) reported by the 17 REs increased by 32.4% to 0.94 mSv in 2019-20 from 0.71 mSv reported in 2018-19, indicating that the mean ED is approaching the 1 mSv annual dose estimate at which regulatory intervention should be considered. The mean committed effective dose (CED) from inhalation of dusts containing long-lived alpha-emitting (LLα) nuclides has increased by 35% from 0.40 mSv in 2018-19 to 0.54 mSv in 2019-20. The maximum CED from LLα increased by 16.3% from 3.20 mSv in 2018-19 to 3.72 mSv in 2019-20. The authors consider that, in the absence of other explanations provided by the REs, the increase is largely attributable to the revised DC’s published in ICRP-137 and ICRP-141, but highlight that there are significant variations between REs that make a generalised conclusion problematic. The maximum reported ED in 2019-20 was 6.0 mSv, an increase of 36.4% from 2018-19 (4.4 mSv). The 2019-20 reporting period is the first time in a decade in which mine worker EDs have been elevated to the point that EDs have exceeded 5 mSv, a level at which personal monitoring and additional institutional controls are required.


Nature ◽  
1969 ◽  
Vol 221 (5183) ◽  
pp. 831-833 ◽  
Author(s):  
M. J. DUGGAN ◽  
E. GREENSLADE ◽  
B. E. JONES

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