The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements.
This paper exploits the possibility of using commercial software for thermoluminescence and optically stimulated luminescence curve deconvolution analysis. The widely used software package Microsoft Excel, with the Solver utility has been used to perform deconvolution analysis to both experimental and reference glow curves resulted from the GLOw Curve ANalysis INtercomparison project. The simple interface of this programme combined with the powerful Solver utility, allows the analysis of complex stimulated luminescence curves into their components and the evaluation of the associated luminescence parameters.
The Mayak Worker Dosimetry System (MWDS-2013) is a system for interpreting measurement data from Mayak workers from both internal and external sources. This paper is concerned with the calculation of annual organ doses for Mayak workers exposed to plutonium aerosols, where the measurement data consists mainly of activity of plutonium in urine samples. The system utilises the latest biokinetic and dosimetric models, and unlike its predecessors, takes explicit account of uncertainties in both the measurement data and model parameters. The aim of this paper is to describe the complete MWDS-2013 system (including model parameter values and their uncertainties) and the methodology used (including all the relevant equations) and the assumptions made. Where necessary, Supplementary papers which justify specific assumptions are cited.
While radiation health risks at low doses have traditionally been estimated from high-dose studies, we have reviewed recent literature and concluded that the mechanisms of action for many biological endpoints may be different at low doses from those observed at high doses; that acute doses < 100 mSv may be too small to allow epidemiological detection of excess cancers given the background of naturally occurring cancers; that low-dose radiation research should use holistic approaches such as systems-based methods to develop models that define the shape of the dose-response relationship; and that these results should be combined with the latest epidemiology to produce a comprehensive understanding of radiation effects that addresses both damage, likely with a linear effect, and response, possibly with non-linear consequences. Continued research is needed to understand how radiobiology and epidemiology advances should be used to effectively model radiation worker risks.
The aim of this study was to evaluate and compare organ doses delivered to patients in wrist and petrous bone examinations using a multislice spiral computed tomography (CT) and a C-arm cone-beam CT equipped with a flat-panel detector (XperCT). For this purpose, doses to the target organ, i.e. wrist or petrous bone, together with those to the most radiosensitive nearby organs, i.e. thyroid and eye lens, were measured and compared. Furthermore, image quality was compared for both imaging systems and different acquisition modes using a Catphan phantom. Results show that both systems guarantee adequate accuracy for diagnostic purposes for wrist and petrous bone examinations. Compared with the CT scanner, the XperCT system slightly reduces the dose to target organs and shortens the overall duration of the wrist examination. In addition, using the XperCT enables a reduction of the dose to the eye lens during head scans (skull base and ear examinations).
The widespread use of cone-beam CT (CBCT) in dentistry has led to increasing concern regarding justification and optimisation of CBCT exposures. When used as a substitute to multidetector CT (MDCT), CBCT can lead to significant dose reduction; however, low-dose protocols of current-generation MDCTs show that there is an overlap between CBCT and MDCT doses. More importantly, although the 3D information provided by CBCT can often lead to improved diagnosis and treatment compared with 2D radiographs, a routine or excessive use of CBCT would lead to a substantial increase of the collective patient dose. The potential use of CBCT for paediatric patients (e.g. developmental disorders, trauma and orthodontic treatment planning) further increases concern regarding its proper application. This paper provides an overview of justification and optimisation issues in dental and maxillofacial CBCT. The radiation dose in CBCT will be briefly reviewed. The European Commission's Evidence Based Guidelines prepared by the SEDENTEXCT Project Consortium will be summarised, and (in) appropriate use of CBCT will be illustrated for various dental applications.
The method to estimate total skeleton plutonium burden of former Mayak Production Association (MPA) workers from limited bone samples obtained at autopsy is described. From two to nine bone samples were obtained at autopsies conducted from the mid-1950s to 2013. Plutonium was measured using alpha-radiometry up to 2000 and later by alpha-spectrometry. The method was validated using data from whole-body donations from the United States Transuranium and Uranium Registries (USTUR). The developed algorithm overestimated the USTUR values from 20 to 40%, that is quite acceptable for conservative estimation. Late-in-life liver diseases known to redistribute plutonium between liver and skeleton were not associated with significant differences in plutonium deposition among sampled bones, except for the pelvis. Sources of uncertainties are discussed and future studies will address the reduction of these uncertainties. This algorithm can be used to obtain data in support of the development of biokinetic, dosimetric and risk models for humans exposed to plutonium.
In the event of a mass casualty radiation incident, the gamma-H2AX foci assay could be a useful tool to estimate radiation doses received by individuals. The rapid processing time of blood samples of just a few hours and the potential for batch processing, enabling high throughput, make the assay ideal for early triage categorisation to separate the 'worried well' from the low and critically exposed by quantifying radiation-induced foci in peripheral blood lymphocytes. Within the RENEB framework, 8 European laboratories have taken part in the first European gamma-H2AX biodosimetry exercise, which consisted of a telescoring comparison of 200 circulated foci images taken from 8 samples, and a comparison of 10 fresh blood lymphocyte samples that were shipped overnight to participating labs 4 or 24 h post-exposure. Despite large variations between laboratories in the dose-response relationship for foci induction, the obtained results indicate that the network should be able to use the gamma-H2AX assay for rapidly identifying the most severely exposed individuals within a cohort who could then be prioritised for accurate chromosome dosimetry.
This paper presents the dosimetry part of the European ELDO project, funded by the DoReMi Network of Excellence, in which a method was developed to estimate cumulative eye lens doses for past practices based on personal dose equivalent values, H-p(10), measured above the lead apron at several positions at the collar, chest and waist levels. Measurement campaigns on anthropomorphic phantoms were carried out in typical interventional settings considering different tube projections and configurations, beam energies and filtration, operator positions and access routes and using both mono-tube and biplane X-ray systems. Measurements showed that eye lens dose correlates best with H-p(10) measured on the left side of the phantom at the level of the collar, although this correlation implicates high spreads (41 ). Nonetheless, for retrospective dose assessment, H-p(10) records are often the only option for eye dose estimates and the typically used chest left whole-body dose measurement remains useful.
Abstract A two-phased retrospective cross-sectional study analysed the occupational dose and radiation protection practice among medical workers in two hospitals in the UAE. Phase 1 evaluated radiation protection practice using a questionnaire, whereas phase 2 assessed the occupational dose. Readings of 952 thermoluminescence dosimeters were analyzed. The result showed 52% of medical workers have a good level of radiation protection practice. Readings of 952 thermoluminescence dosimeters were analyzedAverage annual effective dose per worker ranged from 0.39 to 0.83 mSv. Cardiologists and nurses displayed a higher average of occupational radiation dose compared to other workers. There were no significant correlations between radiation protection practice and hospital, occupation or department. Finally, the occupational dose was within the international and national limits, but the reduction of radiation dose to cardiologist and nurses is essential. Moreover, training is essential to promote radiation safe practice among medical workers.
Abstract An intercomparison exercise (IC) on whole body dosemeters to determine the quantity personal dose equivalent Hp (10) in photon radiation fields was jointly organised and conducted by the International Atomic Energy Agency (IAEA) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for individual monitoring services (IMS) in Asia and the Pacific region. This was arranged to help the IMS in the region to achieve a more accurate dosimetry service and to improve their performance. Twenty-four IMS participated in this IC. Four sets of dosemeters were irradiated using X-ray and gamma radiation qualities at 0° and 20° angle of incidence, respectively. All the IMS provided results that were within the acceptable limits defined by the IAEA. However, only a minority of participants reported confidence intervals that included the reference dose, for each exposure scenario. For few systems, the overall performance could be significantly improved by reviewing calibration procedures.
Abstract The radiological assessment of rock samples from four quarry sites in Ibadan have been carried out. The mean activity concentrations of 40K, 226Ra and 232Th were 377.0 ± 37.9, 17.7 ± 3.6 and 4.98 ± 2.1 Bq kg−1, respectively, for Ratcon Quarry (RQ); 408.0 ± 28.7, 16.6 ± 1.6 and 10.6 ± 2.3 Bq kg−1, respectively, for Dekit Quarry; 388.0 ± 26.6, 15.7 ± 1.9 and 9.85 ± 3.9 Bq kg−1, respectively, for Hajaig Quarry; and 388.084 ± 55.9, 16.2 ± 3.9 and 12.1 ± 3.8 Bq kg−1, respectively, for NSCE Quarry (NQ). The highest mean outdoor effective dose of 0.038 ± 0.005 mSv y−1 and the minimum of 0.033 ± 0.004 mSv y−1 were obtained at NQ and RQ, respectively. The radiological hazard indices recorded in each site were <1.0. The results show lower radioactivity levels than the world average values; therefore, no serious radiological health effect is expected when the crushed rocks from the quarries are used for buildings construction.
Abstract Radiation measurements were made to support radiation protection decisions and instructions concerning the release of patients receiving 131I treatment in Sudan. In hyperthyroidism, administered activity ranged from 370 to 1110 MBq (average: 817.8 MBq), and air-absorbed dose rate at 1 m in front of the patients varied from 20 to 66 μGy h−1 (average: 47.0 μGy h−1). For thyroid cancer patients, the administered activity ranged from 3700 to 7400 MBq (average: 4816.2 MBq), and the air-absorbed dose rate at 1 m in front of the patients ranged from 3 to 55 μSv h−1 (average: 19.2 μSv h−1). On average, the contamination activity was highest in the patients’ clothes: 11.0 Bq cm−2, followed by the toilet: 6.6 Bq cm−2 and the front bed: 2.9 Bq cm−2. The estimated release times from the confinement were well with the radiation safety criteria, whereas instruction are given concerning precaution times to limit radiation exposure to family members and co-worker.
Abstract The aim of the study was to estimate occupational radiation dose to the eye lens of radiologists and the dose reduction ratio of lead glasses during interventional radiology. Three interventional radiologists monitored Hp(3) using small-type optically stimulated luminescence dosemeters attached to the left inside and outside of the lead glasses with 0.07-mmPb [Hp(3)eye]. Hp(10) and Hp(0.07) were monitored, respectively, by attaching the personal dosemeter to the lead neck collar above the lead apron. The median Hp(3)eye with lead glasses and the median dose reduction ratio of lead glasses for the three radiologists were 8.02 mSv/y and 57.7%, respectively. The median Hp(3)eye without lead glasses [Hp(3)eye-w/o] for the three radiologists was 18.6 mSv/y, but Hp(3)eye-w/o for one of the radiologists was 24.1 mSv/y. Monitoring occupational radiation dose to the eye lens is important because interventional radiologists are at risk of exceeding the new dose limit.
Abstract Interventional radiology (IR) procedures tend to be complex, which delivers high radiation exposure to patient. In the present study, we measured the radiation exposure dose [Hp(3)] in the eye using a direct eye dosemeter placed next to the physician’s eye during procedures. Physicians wore a direct eye dosemeter just lateral to eyes and an additional direct eye dosemeter outside the radiation protective eyeglasses close to their eyes. Additionally, a neck glass badge was worn at the neck. Although we found a positive correlation between the left neck glass badge dose [Hp(0.07)] and the left eye lens dose [Hp(3)], the value of R2 of the regression equation were 0.62 and 0.71 (outside and inside). We thought that the exact eye lens dose might not be estimated from the neck glass badge. In conclusion, a correct evaluation of the lens dose [Hp(3)] using the direct eye dosemeter is recommended for tachyarrhythmia physicians.
Abstract Interventional cardiology procedures can involve relatively high radiation doses compared to general radiography. During coronary angiography (CAG) and percutaneous transluminal coronary intervention (PCI), the same area is exposed to radiation for a long period. In this study, radiation exposure data of 1071 examinations in Korean hospitals were collected, and the achievable dose (AD) and diagnostic reference levels (DRLs) in actual medical practice for two types of interventional cardiology procedures in Korea were established. In CAG, 75th percentile DRLs and AD of the total kerma-area product were 47.0 and 33.1 Gy·cm 2, respectively. In PCI, those values were 171.3 and 102.6 Gy·cm2, respectively. This is the first study to introduce the DRLs for cardiovascular interventional procedures in Korea. These results will help optimise the interventional cardiology procedures for Korean cardiac centres.
Abstract A radiological analysis of hot spring water of Hammam Debagh (also called Hammam Meskhoutine) and its associated deposits was realized. Hammam Debagh is considered to be the second hottest springs in the world with a temperature of 98°C and this lead to the creation of travertine. This later was formed because of limestone deposited by mineral springs in a rapid sedimentation of calcium, magnesium bicarbonates, and sulphides. The analysis showed that two-thirds of radioactivity was left by spring water in their deposits. The presence of uranium in the spring deposits was due to the property of the uranyl ion to form stable complexes with carbonates and precipitates. The radiation hazards indexes were estimated and compared with those given in literature.
Radiation dose to the eye lens is a crucial issue for interventional cardiologists (ICs) who are exposed during the procedures they perform. This paper presents a retrospective assessment of the cumulative eye lens doses of ICs enrolled in the OCLOC study for Occupational Cataracts and Lens Opacities in interventional Cardiology. Information on the workload in the catheterisation laboratory, radiation protection equipment, eye lens dose per procedure and dose reduction factors associated with eye-protective equipment were considered. For the 129 ICs at an average age of 51 who had worked for an average period of 22 years, the estimated cumulative eye lens dose ranged from 25 mSv to more than 1600 mSv; the meanSD was 423359 mSv. After several years of practice, without eye protection, ICs may exceed the new ICRP lifetime eye dose threshold of 500 mSv and be at high risk of developing early radiation-induced cataracts. Radiation protection equipment can reduce these doses and should be used routinely.
A comparative study of the dosimetric features of alpha-Al2O3:C,Mg and alpha-Al2O3:C relevant to thermoluminescence dosimetry is reported. A glow curve of alpha-Al2O3:C,Mg measured at 1A degrees C/s after beta irradiation to 1 Gy shows two subsidiary peaks at 42A degrees C (labelled as I) and 72A degrees C (II) and the main peak at 161A degrees C (III) whereas a glow curve of alpha-Al2O3:C measured under the same conditions shows the main peak at 178A degrees C (II') and a lower intensity peak at 48A degrees C (I'). Apart from these ones, there are several other peaks at temperatures beyond that of the main peak in both alpha-Al2O3:C,Mg and alpha-Al2O3:C. However, the latter are not included in this study. We report a comparative quantitative analysis of dose response and fading of peaks I, II and III of alpha-Al2O3:C,Mg and peaks I' and II' of alpha-Al2O3:C. Analysis shows that the dose response of peaks I and III is sublinear within 1-10 Gy whereas that of peak II is superlinear within 1-4 Gy followed by a sublinear region within 4-10 Gy. In comparison, the dose response of peak I' is superlinear within 1-4 Gy followed by a sublinear region within 4-10 Gy whereas that of peak II' is sublinear within 1-4 Gy followed by a superlinear region within 4-10 Gy. As regards to fading corresponding to 1 Gy, peak I is very unstable and fades within 300 s, peak II is more stable and takes up to 43200 s to fade. In comparison, peak III fades down to 30% of its initial intensity within 2400 s. Interestingly, between 2400 and 800 s, the intensity fades by 17% only. Regarding fading in alpha-Al2O3:C, peak I' fades within 600 s whereas peak II' shows an inverse fading behaviour up to 64800 s. The rate of fading for peaks I, II and III in alpha-Al2O3:C,Mg was found to decrease with increase in dose. However, no such behaviour was observed in alpha-Al2O3:C. The fading in both samples is discussed on the basis of a charge hopping mechanism.