Table of contents

A thorough literature review about the current situation on the implementation of eye lens monitoring has been performed in order to provide recommendations regarding dosemeter types, calibration procedures and practical aspects of eye lens monitoring for interventional radiology personnel. Most relevant data and recommendations from about 100 papers have been analysed and classified in the following topics: challenges of today in eye lens monitoring; conversion coefficients, phantoms and calibration procedures for eye lens dose evaluation; correction factors and dosemeters for eye lens dose measurements; dosemeter position and influence of protective devices. The major findings of the review can be summarised as follows: the recommended operational quantity for the eye lens monitoring is H_p(3). At present, several dosemeters are available for eye lens monitoring and calibration procedures are being developed. However, in practice, very often, alternative methods are used to assess the dose to the eye lens. A summary of correction factors found in the literature for the assessment of the eye lens dose is provided. These factors can give an estimation of the eye lens dose when alternative methods, such as the use of a whole body dosemeter, are used. A wide range of values is found, thus indicating the large uncertainty associated with these simplified methods. Reduction factors from most common protective devices obtained experimentally and using Monte Carlo calculations are presented. The paper concludes that the use of a dosemeter placed at collar level outside the lead apron can provide a useful first estimate of the eye lens exposure. However, for workplaces with estimated annual equivalent dose to the eye lens close to the dose limit, specific eye lens monitoring should be performed. Finally, training of the involved medical staff on the risks of ionising radiation for the eye lens and on the correct use of protective systems is strongly recommended.

Given the increasing use of computed tomography (CT) in the UK over the last 30 years, it is essential to ensure that all imaging protocols are optimised to keep radiation doses as low as reasonably practicable, consistent with the intended clinical task. However, the complexity of modern CT equipment can make this task difficult to achieve in practice. Recent results of local patient dose audits have shown discrepancies between two Philips CT scanners that use the DoseRight 2.0 automatic exposure control (AEC) system in the 'automatic' mode of operation. The use of this system can result in drifting dose and image quality performance over time as it is designed to evolve based on operator technique.

The purpose of this study was to develop a practical technique for configuring examination protocols on four CT scanners that use the DoseRight 2.0 AEC system in the 'manual' mode of operation. This method used a uniform phantom to generate reference images which form the basis for how the AEC system calculates exposure factors for any given patient.

The results of this study have demonstrated excellent agreement in the configuration of the CT scanners in terms of average patient dose and image quality when using this technique. This work highlights the importance of CT protocol harmonisation in a modern Radiology department to ensure both consistent image quality and radiation dose. Following this study, the average radiation dose for a range of CT examinations has been reduced without any negative impact on clinical image quality.

In recent years there has been growing interest in the use of neutron scanning techniques for security. Neutron techniques with a range of energy spectra including thermal, white and fast neutrons have been shown to work in different scenarios. As international interest in neutron scanning increases the risk of activating cargo, especially foodstuffs must be considered.

There has been a limited amount of research into the activation of foods by neutron beams and we have sought to improve the amount of information available. In this paper we show that for three important metrics; activity, ingestion dose and Time to Background there is a strong dependence on the food being irradiated and a weak dependence on the energy of irradiation.

Previous studies into activation used results based on irradiation of pharmaceuticals as the basis for research into activation of food. The earlier work reports that $^{24}Na$ production is the dominant threat which motivated the search for $^{23}$Na${{(n,\gamma )}^{24}}$Na in highly salted foods. We show that $^{42}$K can be more significant than $^{24}$Na in low sodium foods such as Bananas and Potatoes.

Mortality from circulatory diseases (CD) (ICD-9 codes 390–459) was studied in an extended Mayak worker cohort, which included 22 377 workers first employed at the Mayak Production Association in 1948–1982 and followed up to the end of 2008. The enlarged cohort and extended follow-up as compared to the previous analyses provided an increased number of deaths from CD and improved statistical power of this mortality study. The analyses were based on dose estimates provided by a new Mayak Worker Dosimetry System 2008 (MWDS-2008). For the first time in the study of non-cancer effects in this cohort quantitative smoking data (smoking index) were taken into account.

A significant increasing trend for CD mortality with increasing dose from external gamma-rays was found after having adjusted for non-radiation factors; the excess relative risk per unit dose (ERR/Gy) was 0.05 (95% confidence interval (CI):  >0, 0.11). Inclusion of an additional adjustment for dose from internal alpha-radiation to the liver resulted in a two-fold increase of ERR/Gy = 0.10 (95% CI: 0.02, 0.21).

A significant increasing trend in CD mortality with increasing dose from internal alpha-radiation to the liver was observed (ERR/Gy = 0.27, 95% CI: 0.12, 0.48). However the ERR/Gy decreased and lost its significance after adjusting for dose from external gamma-rays.

Results of the current study are in good agreement with risk estimates obtained for the Japanese LSS cohort as well as other studies of cohorts of nuclear workers.

The risk of lung cancer mortality up to 75 years of age due to radon exposure has been estimated for both male and female continuing, ex- and never-smokers, based on various radon risk models and exposure scenarios. We used risk models derived from (i) the BEIR VI analysis of cohorts of radon-exposed miners, (ii) cohort and nested case-control analyses of a European cohort of uranium miners and (iii) the joint analysis of European residential radon case-control studies. Estimates of the lifetime lung cancer risk due to radon varied between these models by just over a factor of 2 and risk estimates based on models from analyses of European uranium miners exposed at comparatively low rates and of people exposed to radon in homes were broadly compatible. For a given smoking category, there was not much difference in lifetime lung cancer risk between males and females. The estimated lifetime risk of radon-induced lung cancer for exposure to a concentration of 200 Bq m⁻³ was in the range 2.98–6.55% for male continuing smokers and 0.19–0.42% for male never-smokers, depending on the model used and assuming a multiplicative relationship for the joint effect of radon and smoking. Stopping smoking at age 50 years decreases the lifetime risk due to radon by around a half relative to continuing smoking, but the risk for ex-smokers remains about a factor of 5–7 higher than that for never-smokers. Under a sub-multiplicative model for the joint effect of radon and smoking, the lifetime risk of radon-induced lung cancer was still estimated to be substantially higher for continuing smokers than for never smokers. Radon mitigation—used to reduce radon concentrations at homes—can also have a substantial impact on lung cancer risk, even for persons in their 50 s; for each of continuing smokers, ex-smokers and never-smokers, radon mitigation at age 50 would lower the lifetime risk of radon-induced lung cancer by about one-third. To maximise risk reductions, smokers in high-radon homes should both stop smoking and remediate their homes.

The Bayesian framework has been shown to be very useful in cytogenetic dose estimation. This approach allows description of the probability of an event in terms of previous knowledge, e.g. its expectation and/or its uncertainty.

A new R package entitled radir (radiation inverse regression) has been implemented with the aim of reproducing a recent Bayesian-type dose estimation methodology. radir adopts the method of dose estimation under the Poisson assumption of the responses (the chromosomal aberrations counts) for the required dose-response curve (typically linear or quadratic).

The individual commands are described in detail and relevant examples of the use of the methods and the corresponding radir software tools are given. The suitability of this methodology is highlighted and its application encouraged by providing a user-friendly command-type software interface within the R statistical software (version 3.1.1 or higher), which includes a complete manual.

In compliance with the fundamentals of the government's policy in the field of nuclear and radiation safety approved by the President of the Russian Federation, Russia has developed a national program for decommissioning of its nuclear legacy. Under this program, the State Atomic Energy Corporation 'Rosatom' is carrying out remediation of a Site for Temporary Storage of spent nuclear fuel (SNF) and radioactive waste (RW) at Andreeva Bay located in Northwest Russia. The short term plan includes implementation of the most critical stage of remediation, which involves the recovery of SNF from what have historically been poorly maintained storage facilities. SNF and RW are stored in non-standard conditions in tanks designed in some cases for other purposes. It is planned to transport recovered SNF to PA 'Mayak' in the southern Urals. This article analyses the current state of the radiation safety supervision of workers and the public in terms of the regulatory preparedness to implement effective supervision of radiation safety during radiation-hazardous operations. It presents the results of long-term radiation monitoring, which serve as informative indicators of the effectiveness of the site remediation and describes the evolving radiation situation. The state of radiation protection and health care service support for emergency preparedness is characterized by the need to further study the issues of the regulator-operator interactions to prevent and mitigate consequences of a radiological accident at the facility. Having in mind the continuing intensification of practical management activities related to SNF and RW in the whole of northwest Russia, it is reasonable to coordinate the activities of the supervision bodies within a strategic master plan. Arrangements for this master plan are discussed, including a proposed programme of actions to enhance the regulatory supervision in order to support accelerated mitigation of threats related to the nuclear legacy in the area.

The purpose of this study is to estimate the organ and effective dose (E) from computed tomography coronary angiography (CTCA) on a 320-MDCT scanner. Radiation dose was estimated for the prospectively ECG-gated CTCA in a male phantom. A total of 451 chips of thermoluminescent dosimeter were implanted in the phantom for measuring the organ doses. The effective doses were calculated using measured organ doses and the tissue-weighting factors. The dose length product (DLP) values were recorded and used to develop the conversion coefficient k = 0.017 mSv•(mGy•cm)⁻¹ (E/DLP). In a 3-beat acquisition, the organ doses ranged from 0.24 to 71.55 mGy, and the doses in breast, bone surface, oesophagus, and lung were higher than 20 mGy. The effective doses in 2-beat and 3-beat acquisition were estimated to be 14.3 and 24.3 mSv. More beats of acquisition led to higher radiation dose. The reported k values for chest CT scan can be used to roughly estimate the E value from CTCA for 320 MDCT.

Computed tomography (CT) has great clinical utility and its usage has increased dramatically over the years. Concerns have been raised, however, about health impacts of ionising radiation exposure from CTs, particularly in children, who have a higher risk for some radiation induced diseases. Direct estimation of the health impact of these exposures is needed, but the conduct of epidemiological studies of paediatric CT populations poses a number of challenges which, if not addressed, could invalidate the results.

The aim of the present paper is to review the main challenges of a study on the health impact of paediatric CTs and how the protocol of the European collaborative study EPI-CT, coordinated by the International Agency for Research on Cancer (IARC), is designed to address them.

The study, based on a common protocol, is being conducted in Belgium, Denmark, France, Germany, the Netherlands, Norway, Spain, Sweden and the United Kingdom and it has recruited over one million patients suitable for long-term prospective follow-up. Cohort accrual relies on records of participating hospital radiology departments. Basic demographic information and technical data on the CT procedure needed to estimate organ doses are being abstracted and passive follow-up is being conducted by linkage to population-based cancer and mortality registries. The main issues which may affect the validity of study results include missing doses from other radiological procedures, missing CTs, confounding by CT indication and socioeconomic status and dose reconstruction. Sub-studies are underway to evaluate their potential impact.

By focusing on the issues which challenge the validity of risk estimates from CT exposures, EPI-CT will be able to address limitations of previous CT studies, thus providing reliable estimates of risk of solid tumours and leukaemia from paediatric CT exposures and scientific bases for the optimisation of paediatric CT protocols and patient protection.

The aim of this study is to evaluate organ and tissue absorbed doses to patients undergoing hepatic chemoembolization procedures performed in two hospitals in the city of Recife, Brazil. Forty eight patients undergoing fifty hepatic chemoembolization procedures were investigated. For the 20 cases with PA projection only, organs and tissues dose to KAP conversion coefficients were calculated using the mesh-based anthropometric phantom series FASH and MASH coupled to the EGSnrc Monte Carlo code. Clinical, dosimetric and irradiations parameters were registered for all patients. The maximum organ absorbed doses found were 2.4 Gy, 0.85 Gy, 0.76 Gy and 0.44 Gy for skin, kidneys, adrenals and liver, respectively.

The quest for new sensing phenomena continues because detecting, discriminating, identifying, measuring and monitoring nuclear materials and their radiation from greater range, at lower concentrations, and in a more timely fashion brings greater safety, security and efficiency. The potential phenomena are diverse, and those that have been realised can be found in disparate fields of science, engineering and medicine, which makes the full range difficult to realise and record. The framework presented here offers a means to systematically and comprehensively explore nuclear sensing phenomena. The approach is based on the fundamental concepts of matter and energy, where the sequence starts with the original nuclear material and its emissions, and progressively considers signatures arising from secondary effects and the emissions from associated materials and the environment. Concepts of operations such as active and passive interrogation, and networked sensing are considered. In this operational light, unpacking nuclear signatures forces a fresh look at the sensing concept. It also exposes how some phenomena that exist in established technology may be considered novel based on how they could be exploited rather than what they fundamentally are. This article selects phenomena purely to illustrate the framework and how it can be best used to foster creativity in the quest for novel phenomena rather than exhaustively listing, categorising or comparing any practical aspects of candidate phenomena.

A biokinetic model for strontium (Sr) for the pregnant woman and fetus (Sr-PWF model) has been developed for use in the quantification of doses from internal radiation exposures following maternal ingestion of Sr radioisotopes before or during pregnancy. The model relates in particular to the population of the Techa River villages exposed to significant amounts of ingested Sr radioisotopes as a result of releases of liquid radioactive wastes from the Mayak plutonium production facility (Russia) in the early 1950s. The biokinetic model for Sr metabolism in the pregnant woman was based on a biokinetic model for the adult female modified to account for changes in mineral metabolism during pregnancy. The model for non-pregnant females of all ages was developed earlier with the use of extensive data on ⁹⁰Sr-body measurements in the Techa Riverside residents. To determine changes in model parameter values to take account of changing mineral metabolism during pregnancy, data from longitudinal studies of calcium homeostasis during human pregnancy were analysed and applied. Exchanges between maternal and fetal circulations and retention in fetal skeleton and soft tissues were modelled as adaptations of previously published models, taking account of data on Sr and calcium (Ca) metabolism obtained in Russia (Southern Urals and Moscow) relating to dietary calcium intakes, calcium contents in maternal and fetal skeletons and strontium transfer to the fetus. The model was validated using independent data on ⁹⁰Sr in the fetal skeleton from global fallout as well as unique data on ⁹⁰Sr-body burden in mothers and their still-born children for Techa River residents. While the Sr-PWF model has been developed specifically for ingestion of Sr isotopes by Techa River residents, it is also more widely applicable to maternal ingestion of Sr radioisotopes at different times before and during pregnancy and different ages of pregnant women in a general population.

This paper presents a biokinetic model for strontium metabolism in the lactating woman and transfer to breast milk for members of Techa River communities exposed as a result of discharges of liquid radioactive wastes from the Mayak plutonium production facility (Russia) in the early 1950s. This model was based on that developed for the International Commission for Radiological Protection with modifications to account for population specific features of breastfeeding and maternal bone mineral metabolism. The model is based on a biokinetic model for the adult female with allowances made for changes in mineral metabolism during periods of exclusive and partial breast-feeding. The model for females of all ages was developed earlier from extensive data on ⁹⁰Sr-body measurements for Techa Riverside residents. Measurements of ⁹⁰Sr concentrations in the maternal skeleton and breast milk obtained in the1960s during monitoring of global fallout in the Southern Urals region were used for evaluation of strontium transfer to breast and breast milk. The model was validated with independent data from studies of global fallout in Canada and measurements of ⁹⁰Sr body-burden in women living in the Techa River villages who were breastfeeding during maximum ⁹⁰Sr-dietary intakes. The model will be used in evaluations of the intake of strontium radioisotopes in breast milk by children born in Techa River villages during the radioactive releases and quantification of ⁹⁰Sr retention in the maternal skeleton.

Epidemiological evidence of increased risks for childhood leukaemia from magnetic fields has implicated, as one source of such fields, high-voltage overhead lines. Magnetic fields are not the only factor that varies in their vicinity, complicating interpretation of any associations. Underground cables (UGCs), however, produce magnetic fields but have no other discernible effects in their vicinity. We report here the largest ever epidemiological study of high voltage UGCs, based on 52 525 cases occurring from 1962–2008, with matched birth controls. We calculated the distance of the mother's address at child's birth to the closest 275 or 400 kV ac or high-voltage dc UGC in England and Wales and the resulting magnetic fields. Few people are exposed to magnetic fields from UGCs limiting the statistical power. We found no indications of an association of risk with distance or of trend in risk with increasing magnetic field for leukaemia, and no convincing pattern of risks for any other cancer. Trend estimates for leukaemia as shown by the odds ratio (and 95% confidence interval) per unit increase in exposure were: reciprocal of distance 0.99 (0.95–1.03), magnetic field 1.01 (0.76–1.33). The absence of risk detected in relation to UGCs tends to add to the argument that any risks from overhead lines may not be caused by magnetic fields.

The S values for the thyroid as the radioiodine source organ to other target organs were investigated using Chinese hybrid reference phantoms and the Monte Carlo code MCNP5. Two radioiodine isotopes ¹²⁵I and ¹³¹I uniformly distributed in the thyroid were investigated separately. We compared our S values for ¹³¹I in Chinese phantoms with previous studies using other types of phantoms: Oak Ridge National Laboratory (ORNL) stylized phantoms, International Commission on Radiological Protection (ICRP) voxel phantoms, and University of Florida (UF) phantoms. Our results are much closer to the UF phantoms. For each specific target organ, the S value for ¹³¹I is larger than for ¹²⁵I in both male and female phantoms. In addition, the S values and effective dose to surrounding face-to-face exposed individuals, including different genders and ages (10- and 15-year-old juniors, and adults) from an adult male radioiodine carrier were also investigated. The target organ S values and effective dose for surrounding individuals obey the inverse square law with the distance between source and target phantoms. The obtained effective dose data in Chinese phantoms are comparable to the results in a previous study using the UF phantoms. The data generated in this study can serve as the reference to make recommendations for radiation protection of the Chinese patients or nuclear workers.

The radioactivity levels of some sachet-packaged drinking water produced and used in Owo, a local government area of Ondo State, Nigeria, were measured. The activity concentrations of ²²⁶Ra varied between 0.6   ±   0.2 Bq L⁻¹ and 11.6   ±   3.2 Bq L⁻¹ with an arithmetic mean  ±  standard deviation of 6.6   ±   3.6 Bq L⁻¹, the activity concentrations of ²²⁸Ra varied between 4.5   ±   2.1 Bq L⁻¹ and 18.6   ±   6.1 Bq L⁻¹ with an arithmetic mean  ±  standard deviation of 12.2   ±   4.5 Bq L⁻¹ and that of ⁴⁰K varied between 22   ±   6 Bq L⁻¹ and 142   ±   41 Bq L⁻¹ with an arithmetic mean  ±  standard deviation of 68   ±   45 Bq L⁻¹. ⁴⁰K was not detected in one sample. The resulting annual effective doses due to ingestion of the radionuclides ²²⁶Ra and ²²⁸Ra in the water samples varied between 2.4 mSv and 11.5 mSv with an arithmetic mean  ±  standard deviation of 7.5   ±   2.8 mSv, which are higher than the recommended standards of WHO and UNSCEAR. Therefore this study shows that it is not radiologically advisable to consume any of the sachet drinking water studied.

Most existing guidelines to control radionuclides in commercial food were established for nuclear emergency or post-emergency situations. They provide guideline levels only for those radionuclides representative of a nuclear or radiological emergency. Under normal conditions, naturally occurring radionuclides in food could be the main concern for radiological protection and food safety. From the perspective of radiological protection and food safety, guidelines to control radionuclides in foodstuffs are needed in non-emergency situations. The WHO's drinking water guidelines are a good example of radiological guidelines for non-emergency situations which address man-made radionuclides as well as naturally occurring radionuclides. Food safety should meet the same or comparable standards as the standards for drinking water quality. Benefits of having radiological guidelines for commercial food, some practical considerations and proposed criteria to set such guidelines for three food categories are discussed here.

The performance of radiography in the Intensive Care Unit (ICU) may be associated with a certain level of radiation exposure for staff and patients in the unit. Little evidence on exposure levels is available in the literature. However, healthcare professionals in the ICUs at our centre tend to leave the room during radiographic examinations, potentially compromising patient care.

The objectives of this study were to quantify dose levels within the ICU and to evaluate the performance of ICU x-ray studies according to patient dose measurements.

This study was conducted in the 18-bed ICU of a third-level hospital. The scattering radiation due to mobile x-ray examinations was measured by using four personal thermoluminiscent dosimeters (TLDs). The dose area product (DAP) was measured at each examination using a transmission chamber installed on the diaphragm of the x-ray equipment.

Based on the TLD readings and taking account of the error margin, the annual dose to patients and staff was less than 0.6 mSv. The value given by the DAP meter for chest x-rays was 94  ±  17 mGy cm²; this value is well below the lower limit recommended by different agencies and committees.

Exposure levels were found to be extremely low and pose no apparent risk to staff or to those in beds adjacent to the patients undergoing x-ray examinations, which were correctly performed in the unit.

Summaries of the articles in this issue are given in the PDF file.