Mike Youngman

Public Health England | HPA · Centre for Radiation, Chemical and Environmental Hazards (CRCE)

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 biologi...

In case of a nuclear reactor accident affecting a large population the internal contamination of the workers and the public can be assessed through in vivo measurements. Since iodine-131 is one of the most important releases and since it is of health concern, thyroid monitoring of this radionuclide is of special interest. Intercomparisons of thyroi...

Past radiological and nuclear accidents have demonstrated that monitoring a large number of children following a radiological and nuclear emergency can be challenging, in accommodating their needs as well as adapting monitoring protocols and applying age-specific biokinetics to account for various ages and body sizes. This paper presents the derive...

There are ongoing social debates about the risks and benefits of using nuclear reactors to generate electricity. Radiation accidents can occur for different reasons and even be caused deliberately as a result of terrorist actions, and these may affect from a few to thousands of people. After a major release of radioactive iodine as a result of a nu...

Following a severe nuclear reactor accident large amounts of radioactive iodine are released in the atmosphere. Health consequences estimation for the affected population is based on the dose assessment which can be derived from in vivo measurements. Since the uptake of radioactive iodine increases the thyroid cancer risk of children it is of parti...

This report summarizes the findings about parameters influencing thyroid in vivo monitoring of 131 I. The parameters were studied by Monte Carlo calculations using realistic anthropomorphic voxel phantoms and four previously validated detector models (3 NaI detectors and 1 Germanium detectors). The voxel phantoms corresponded to the following ages:...

DESCRIPTION This report gives technical guidelines for radio-iodine monitoring following a nuclear incident. Monitoring aspects addressed include the choice of detectors, the calibration and measurement process, factors affecting measurements, measurement uncertainties, the preparation of equipment and measurement locations, the measurement time, t...

Mr Litvinenko died on 23 November 2006 after having been poisoned with polonium-210 on 1 November. Measurements of the polonium-210 content of post-mortem tissue samples and samples of urine and blood showed the presence of large amounts of ²¹⁰Po. Autoradiography of hair samples showed two regions of ²¹⁰Po activity, providing evidence of an earlier...

The European Model for Inhabited Areas (ERMIN) predicts long-term doses and other consequences following contamination of built-up areas by airborne radioactivity. Central to ERMIN are empirical models of the long-term behaviour of radionuclides on building and other surfaces in the environment. Experiments in which building materials were contamin...

In the event of a radiation emergency, people close to the site of the incident may be exposed to radiation by external exposure, or as a result of intakes of radioactive material. For these incidents it may be necessary to monitor members of the public both for external and internal contamination. This work reviews currently available equipment fo...

Retention in the extrathoracic airways, and clearance by nose blowing, of monodisperse indium-111-labeled polystyrene particles were followed for at least 2 days after inhalation by healthy volunteers. Nine volunteers inhaled 3-μm aerodynamic diameter particles while sitting at rest, whereas subgroups of 3 or 4 inhaled 1.5-μm or 6-μm particles at r...

The part played by individual monitoring within the context of the overall response to incidents involving the malevolent use of radiation or radioactive material is discussed. The main objectives of an individual monitoring programme are outlined, and types of malevolent use scenario briefly described. Some major challenges facing those with respo...

The Human Respiratory Tract Model of the International Commission on Radiological Protection assumes that a fraction of particles deposited in the bronchial tree clears slowly, this fraction decreasing with increasing particle geometric diameter. To test this assumption, volunteers inhaled 5-microm aerodynamic diameter 111In-polystyrene and 198Au-g...

Introduction Several hundred persons across multiple locations were assessed for the possibility of acute exposure during the London 210Polonium incident of October-November 2006. This paper describes the public health risk assessment process and the epidemiology of acute exposure to 210Po for persons at risk during this incident. Methods: Location...

In an emergency involving the deliberate or accidental release of radioactive materials, there could potentially be a large number of people who require monitoring for internal contamination. Doses from these measurements will need to be calculated as quickly as possible. Emergency Response Internal Dose Assessment Software (ERIDAS) has been design...

The ICRP human respiratory tract model (HRTM) assumes that the ‘slow-cleared fraction’ fs in the bronchial (BB) and bronchiolar (bb) regions decreases with increasing particle geometric diameter dp. To test this assumption, five volunteers inhaled 8-µm aerodynamic diameter, dae, 111In-polystyrene (PSL) and 198Au particles simultaneously. The partic...

The National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) for seaweed was developed through an interlaboratory comparison with 24 participants from 16 countries. After evaluating different techniques to calculate certified values for the radionuclides, the median method was found to be the most representative techn...

This paper summarises a comprehensive review of radio-analytical data from autopsy, whole or partial body monitoring and the assay of teeth, foetuses and urine for non-occupationally exposed members of the public in the UK between 1957 and 2003. Most attention has been given to measurements of artificial radionuclides formed in the nuclear fuel cyc...

A transportable in vivo monitoring system has been constructed and calibrated. The system uses two hyper pure germanium detectors--one for measuring whole body activities, by measuring activity in the torso, and the second for determining activities of radioiodine in the thyroid. The optimum counting geometries have been determined and the system h...

The absorption kinetics to blood of plutonium and gadolinium after inhalation as nitrate and oxide in humans and animals has been studied. For each material, values describing the time dependence of absorption were derived from the studies in animals and used with the ICRP human respiratory tract model to predict lung retention and cumulative amoun...

The aim of this work was to investigate the biokinetics of thorium dioxide in animals for the purpose of assessing intakes of the compound by workers and the resulting doses. The results imply that measurements of the decay products in the chest or extrapolations from urine analysis data are unlikely to be of value for doses below 20 mSv. Even high...

In a nuclear weapon accident involving fire or conventional explosion, most of the radiation dose received by people in the immediate vicinity would result from inhalation of 239Pu. This is accompanied by the nuclide 241Am, which is much easier to determine by external counting because of the 60 keV gamma ray emission. In the event of an accident,...

The purpose of these experiments was to measure the differences in total deposition in the nose arising from differences in the breathing patterns. Monodisperse droplets (from 1.7 to ) were deposited in an artificial nasal cavity (cast) using different human breathing patterns as well as under constant flow rate conditions. The human breathing patt...

A study of the deposition and clearance of inhaled particles in the human nasal passage has identified and quantified the major routes of particle transport clearance from the nose. The results of the study have been used to construct a compartment model describing extrathoracic clearance. Experimental evidence for each of the model's clearance rou...

An experimental study of the absorption of inhaled gadolinium oxide from the human respiratory tract was conducted. Preliminary estimates of human respiratory tract model (HRTM) parameters describing the time dependence of absorption were derived and are compared with similar parameters determined from the results of experiments with laboratory ani...

Clearance from the extrathoracic (ET) airways was measured in nine volunteers for up to five days following inhalation of 3 �m aerodynamic diameter particles. An initial assessment of the implications of the results for dose assessment, and a discussion of the potential of nose blow sampling for internal dose monitoring, are given.

The characterisation of an intertidal sediment, containing enhanced levels of radioactivity, collected from the Cumbrian coast of the U.K. by the Laboratory of the Government Chemist for the Department of the Environment is described. A wide variety of radiochemical and instrumental techniques were used including α-spectrometry, β-counting, liquid...

Particle deposition in, and clearance from, the human nasal passage investigations are under way and will last for three years. Monodisperse particles ranging from 0.6 to greater than 30 μm are inhaled under three different breathing regimes; sitting and light exercise as defined in ICRP Publication 66, and controlled breathing. Deposition in the n...

A method is being developed for assessing intakes by inhalation of insoluble thorium by measurement of thoron (²²⁰Rn) in exhaled air. It has been shown that it is possible to collect the short-lived decay products of thoron, ²¹⁶Po and ²¹²Pb, electrostatically. The subsequent counting is done using a silicon surface barrier detector, which gives a h...

A method is being developed for assessing intakes by inhalation of insoluble thorium by measurement of thoron (²²⁰Rn) in exhaled air. It has been shown that it is possible to collect the short-lived decay products of thoron, ²¹⁶Po and ²¹²Pb, electrostatically. The subsequent counting is done using a silicon surface barrier detector, which gives a h...

The performance of the germanium (Ge) detector body monitor that has been recently installed at NRPB Chilton is evaluated and compared with the performance of the existing NRPB scintillation detector body monitor. Calibration of a p-type Ge detector for the measurement of radionuclides distributed throughout the body which emit photons with energie...

The performance of the germanium (Ge) detector body monitor that has been recently installed at NRPB Chilton is evaluated and compared with the performance of the existing NRPB scintillation detector body monitor. Calibration of a p-type Ge detector for the measurement of radionuclides distributed throughout the body which emit photons with energie...

Groundwaters from depths of 350 m to 1250 m in the Stripa granite contain dissolved radiogenic He in amounts up to 50,000 times that due to air-saturation. The groundwater He-contents increase with depth and lie close to the expected profile for He loss by aqueous diffusion (D = 0.032 m2 a−1). Measurements on core samples show that the rock has ret...

Natural radioelement concentrations in groundwaters from the fracture flow regime in the Stripa granite were monitored during the period 1977-1986. Uranium concentrations from depths of 80 m or less and in minewaters from above the hydraulic sink produced by the deepest mining level (410 m), range from 10 to 90 ppb. 234 U / 238 U activity ratios ar...

Ground waters from depths of 350 m to 1,250 m in the Stripa granite contain dissolved radiogenic He in amounts up to 50,000 times that due to air-saturation. The groundwater He-contents increase with depth and lie close to the expected profile for He loss by aqueous diffusion (D = 0.032 m² a⁻¹). Measurements on core samples show that the rock h...

The geochemistry of formation waters in the Molasse basin of Upper Austria has been investigated to ascertain the extent of meteoric water replacement of the connate interstitial fluids in these sediments. The chemistry, isotopic composition, and dissolved gas contents of the groundwaters and of oil and gas associated brines have been determined. T...

The Innviertel (Ottnangian) formation of the Molasse zone of Upper Austria is of major importance as a source of potable water. A hydrochemical, radiochemical and dissolved gas study was undertaken to establish the flow pattern in the Innviertel and its relationship to groundwaters in deeper formations in the Molasse basin.The Innviertel groundwate...

This report reviews for the UK population, experimental data on whole body or partial body monitoring, urine assay, the assay of teeth, autopsy and fetal data for members of the public who have not been exposed occupationally to radionuclides. Most attention has been devoted to artificial radionuclides formed in the nuclear fuel cycle, in particula...