SEARCH · Search PubMed

Results for “RADIATION MONITORING”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources

PubMed2001

Measured and calculated angular responses of panasonic UD-809 thermoluminescence dosemeters to neutrons.

Multi-element thermoluminescence dosemeters (TLD), such as the Panasonic UD-809, are used in personal dosimetry. The Panasonic UD-809 dosemeter consists of one gamma sensitive and three neutron sensitive TLD elements with different filter materials. In this work, the neutron energy responses (the number of (n,alpha) reactions per neutron) of the neutron-sensitive TLD elements of the Panasonic UD-809 dosemeter were calculated using the MCNP Monte Carlo transport code. Experiments were performed in a calibration geometry with an unmoderated 252Cf neutron source. These measurements were made with the dosemeter placed on the centre front face of a polymethylmethacrylate (PMMA) slab phantom. The phantom was rotated in the horizontal plane from -90 to +90 degrees, in 15 degree increments. Good agreement between calculated and measured element responses was observed. The angular dependency of personal dose equivalent was also calculated for parallel beams of 252Cf neutrons and compared to the TLD element angular responses.

Humans↗

PubMed2001

Radiation dose estimates in Indian adults in normal and pathological conditions due to 99Tcm-labelled radiopharmaceuticals.

ICRP Publications 53, 62 and 80 give organ dose coefficients and effective doses to ICRP Reference Man and Child from established nuclear medicine procedures. However, an average Indian adult differs significantly from the ICRP Reference Man as regards anatomical, physiological and metabolic characteristics, and is also considered to have different tissue weighting factors (called here risk factors). The masses of total body and most organs are significantly lower for the Indian adult than for his ICRP counterpart (e.g. body mass 52 and 70 kg respectively). Similarly, the risk factors are lower by 20-30% for 8 out of the 13 organs and 30-60% higher for 3 organs. In the present study, available anatomical data of Indians and their risk factors have been utilised to estimate the radiation doses from administration of commonly used 99Tcm-labelled radiopharmaceuticals under normal and certain pathological conditions. The following pathological conditions have been considered for phosphates/phosphonates--high bone uptake and severely impaired kidney function; IDA--parenchymal liver disease, occlusion of cystic duct, and occlusion of bile duct; DTPA--abnormal renal function; large colloids--early to intermediate diffuse parenchymal liver disease, intermediate to advanced parenchymal liver disease; small colloids--early to intermediate parenchymal liver disease, intermediate to advanced parenchymal liver disease; and MAG3--abnormal renal function, acute unilateral renal blockage. The estimated 'effective doses' to Indian adults are 14-21% greater than the ICRP value from administration of the same activity of radiopharmaceutical under normal physiological conditions based on anatomical considerations alone, because of the smaller organ masses for the Indian; for some pathological conditions the effective doses are 11-22% more. When tissue risk factors are considered in addition to anatomical considerations, the estimated effective doses are still found to be generally somewhat higher for the Indian, for both normal and pathological states (but lower than the values based on anatomical considerations alone). However, when the radiopharmaceutical is administered in quantities proportional to the body mass, the effective doses are 11-28% lower for the Indian under both normal and pathological conditions. It may be concluded that Indians are at a lower risk of radiation health detriment in comparison with the ICRP adult on administration of the various 99Tcm-labelled radiopharmaceuticals considered in this study.

Adult↗

PubMed2001

Fluence to effective dose conversion coefficients for electrons with energy from 1 MeV to 100 GeV.

Fluence to organ dose and effective dose conversion coefficients have been calculated for electrons from 1 MeV to 100 GeV using an anthropomorphic phantom and the EGS4 code. The conversion coefficients were calculated for six typical irradiation geometries taking electromagnetic cascade shower and photonuclear reactions into account. The contribution to the absorbed dose due to the photonuclear reactions in energies up to 140 MeV was evaluated to be less than 0.2%. Even at energies above 140 MeV the dose contributions of the photonuclear reactions were insignificant.

Electrons↗

PubMed2001

Comparison test of electronic dosemeters.

To assist with a planned purchase of electronic dosemeters by the Swiss Federal Office for Civil Protection, the calibration laboratory of the Paul Scherrer Institute performed tests on 11 types of electronic dosemeters manufactured by 10 European and American companies. The technical specifications for the World Trade Organisation (WTO) tendering procedure were largely in accord with the specifications of the international standard IEC 61526. First tests were performed with samples from each type of dosemeter. The reproducibility of a dose of 0.1 mSv generated with 137Cs radiation at a dose rate of 2.1 mSv.h-1 was found adequate for all tested dosemeter types. The response for environmental levels of radiation showed a large variation, indicating insufficient background correction of some dosmeters. A very high dose rate of 10 Sv.h-1 provoked faulty dose readings for more than half of the tested dosemeters. Dosemeter response for low-energy photon radiation was satisfactory for two of the tested dosemeter types. Four dosemeter types were selected for extended technical tests. Three samples of each of these dosemeter types were purchased. For drop and temperature tests the specifications of the WTO tendering procedure outranged the specifications of the IEC standard. Whereas even at a temperature of -25 degrees C the tested dosemeters functioned normally, drops from a height of 2 m onto a wooden surface rendered the samples of two dosemeter types inoperative.

Calibration↗

PubMed2001

A new algorithm for identifying abnormal glow curves in thermoluminescence personal dosimetry.

In this paper an algorithm for the investigation of routine curves in thermoluminescence personal dosimetry is presented. In rare cases, the luminescence glow curves do not exhibit the expected form. They have an abnormal shape as a result of, for example, external contamination, hardware problems, and poor heat transfer. So, glow curves from a monthly exposure period are compared with regular glow curves. Each curve is divided into four regions of interest (ROIs) and the relationships between the different ROIs are analysed. There are few criteria combining all four ROIs, which are necessary to distinguish between normal and abnormal glow curves. For that, the numerical value and the channel of the curves maximum also need to be considered. In most cases an additional set of criteria permits the identification of the ROI in which the irregularity occurs.

Algorithms↗

PubMed2001

EURADOS trial performance test for neutron personal dosimetry.

This paper reports on the results of a neutron trial performance test sponsored by the European Commission and organised by EURADOS. As anticipated, neutron dosimetry results were very dependent on the dosemeter type and the dose calculation algorithm. Fast neutron fields were generally well measured, but particular problems were noted in the determination of intermediate energy fields and large incident angles, demonstrating the difficulties of neutron personal dosimetry. Of particular concern from a radiological protection point of view was the large number of results underestimating personal dose equivalent. A considerable over-response was noted in a few cases.

European Union↗

PubMed2001

IAEA Occupational Radiation Protection Programme.

The objective of the IAEA Occupational Protection Programme is to promote and assist in establishing an internationally harmonised approach for optimising occupational radiation protection. Guidance for IAEA Member States is provided through the hierarchical Safety Standards Series: Safety Fundamentals, Safety Requirements and Safety Guides. A set of three Safety Guides on occupational radiation protection has been published, jointly sponsored by the IAEA and the International Labour Office. Complementary advice, either topic specific or practice specific, is published as Safety Reports in other IAEA publications. In view of the technical difficulties associated with the introduction of the new radiation quantities for measurements and reporting, the IAEA assists its Member States by offering annual dosimetry intercomparisons. The purpose of this paper is to present the current and future IAEA activities in support of occupational radiation protection in the IAEA Member States.

Austria↗

PubMed2001

Intercomparison measurements of extremity dosemeters in beta and/or photon radiation fields.

Beta dosimetry, especially at the extremities, is gaining in importance due to the increasing use of beta particle sources, e.g. in brachytherapy. The dosimetric properties of personal dosemeters to be worn on the extremities and capable of measuring the personal dose equivalent, Hp(0.07), in beta and/or photon radiation fields were investigated within the scope of intercomparison measurements organised by the PTB in two steps. The results were evaluated on the basis of recommendations from the German Commission on Radiological Protection (SSK). In the first step 10 types of dosemeter were investigated in beta particle fields in a range of mean energies from 0.06 MeV to 0.8 MeV. In the second step, five selected beta dosemeter types were exposed to beta particles and, in addition, to photons and to mixtures of both. Three dosemeters fulfill the requirements for the whole range of mean beta energy used for the intercomparison and meet the requirements for photon radiation from 8 keV to 662 keV.

Arm↗

PubMed2001

The NRPB PADC neutron personal dosimetry service.

The UK National Radiological Protection Board has been operating a successful contract neutron personal dosimetry service based on poly-allyl diglycol carbonate (PADC, also known by the trade name CR-39) since 1986, covering about 1500 workers and serving major nuclear sites in the UK and abroad. In that time approximately 100,000 dosemeters have been issued. Since the service was launched, a number of aspects have undergone evolution and it is therefore worthwhile to give an updated summary of how the service operates and performs today. The description covers the choice of plastic and of etching technique, the design of the dosemeter, the features of the automated image analysis, and the characteristics of the control software. Also described are the approaches to calibration and traceability and to compensation for energy and angle dependence, with particular mention of the ability of the service to estimate the quantity Hp(10) in accordance with the requirements of the European Council Directive 96/29/Euratom.

European Union↗

PubMed2001

A method applicable to effective dose rate estimates for aircrew dosimetry.

The inclusion of cosmic radiation as occupational exposure under ICRP Publication 60 and the European Union Council Directive 96/29/Euratom has highlighted the need to estimate the exposure of aircrew. According to a report of the Group of Experts established under the terms of Article 31 of the European Treaty, the individual estimates of dose for flights below 15 km may be done using an appropriate computer program. In order to calculate the radiation exposure at aircraft altitudes, calculations have been performed by means of the Monte Carlo transport code FLUKA. On the basis of the calculated results, a simple method is proposed for the individual evaluation of effective dose rate due to the galactic component of cosmic radiation as a function of latitude and altitude.

Air Pollution, Radioactive↗

PubMed2001

A prototype personal neutron dosemeter with one silicon diode.

The performance of a personal neutron dosemeter with a single silicon diode using a linear combination of its pulse height information was studied. Its dosimetric behaviour in fields with neutrons of different energy and directional distribution is shown for neutron energies ranging from thermal to 100 MeV and for directions of incidence ranging from frontal to lateral. The dosemeter is photon-insensitive and its dose detection threshold is at about 20 microSv. The dosimetric characteristics are compared with those of commercial dosemeters based on silicon detectors.

Consumer Product Safety↗

PubMed2001

The first operational dosemeter for neutrons which complies with IEC standard 1323.

Individual neutron dosimetry represents one of the current difficulties in the field of radiological protection of workers. Since March 1999, the regulatory requirements in France for active (i.e. operational) dosimetry have been those of ICRP Publication 60, applicable from May 2000, necessitating the introduction of a new generation of neutron dosemeters. Over the last few years, the Institute for Nuclear Safety and Protection has been studying an individual electronic dosemeter for neutrons based on a semiconducting detector, capable of meeting the specifications laid down by a neutron dosimetry work group, including members from all the main players in the French nuclear industry. In 1998, the IPSN began transferring technology to the Saphymo company which, by the end of 2001, will be marketing Saphydose-n, the first individual dosemeter for neutrons which complies with IEC Standard 1323. This dosemeter is of compact design and can assess the individual dose equivalent Hp(10) in mixed neutron and gamma radiation fields. It wil be usable in any nuclear facility without prior knowledge of the average neutron spectrum or of the neutron-gamma ratio. It will be possible to connect the Saphydose-n dosemeter to any of the existing gamma deserter terminals to read the dose data and recharge the batteries.

Air Pollution, Radioactive↗

PubMed2001

Study of the photon radiation performance of electronic personal dosemeters.

Following the specifications and test methods given by international standards IEC-61526 and ISO 4037, the dosimetry department of the IPSN studied the photon radiation performance of seven recent electronic personal dosemeters: The personal dosimetric performance of each piece of equipment was tested with X and gamma radiation between 12 keV and 1.25 MeV.

Air Pollution, Radioactive↗

PubMed2001

A prototype personal neutron dosemeter based on an ion chamber and direct ion storage.

Ionisation chambers are sensitive to both neutrons and photons. In order to produce a neutron dosemeter based on an ion chamber a double-chamber system which allows for differential readings has to be built. The system consists of one chamber with high neutron sensitivity (e.g. A-150 or polyethylene with 10B or 6Li compounds) and one chamber with low neutron sensitivity (e.g. graphite or Teflon). Different combined dosemeter prototypes were produced and their responses for standard photon and neutron radiation fields, as well as various field spectra, were determined. The feasibility of neutron dosimetry with ion chambers and direct ion storage (DIS) electronics has been proved. The results obtained with prototype dosemeters indicate the system's promising potential for legal approval in the future. Apart from dosimetric properties, the advantages of the system are its small size and weight, easy readout and relatively low production cost.

Equipment Design↗

PubMed2001

Dose registry in Europe: national databases and international statistics.

This paper describes the approach used in ESOREX to compare national dose statistics of occupational radiation exposure at a European level. As every country uses its own scheme to characterise radiation work, the 'best common denominator' has to be found in order to compare dose statistics. The same problem has to be solved for the dose bands used in each country in order to scale dose distributions.

Czech Republic↗

PubMed2001

The Spanish National Dose Registry and Spanish radiation passbooks.

The Spanish National Dose Registry (BDN) is the Nuclear Safety Council's (CSN) national database of occupational exposure to radiation. Each month BDN receives records of individual external doses from approved dosimetry services. The dose records include information regarding the occupational activities of exposed workers. The dose information and the statistical analysis prepared by the BDN are a useful tool for effective operational protection of occupationally exposed workers and a support for the CSN in the development and application of the ALARA principle. The Spanish radiation passbook was introduced in 1990 and since then CSN, as regulatory authority, has required that all outside workers entering controlled areas should have radiation passbooks. Nowadays, CSN has implemented improvements in the Spanish radiation passbooks, taking into account previous experience and Directive 96/29/EURATOM.

European Union↗

PubMed2001

Regulatory approval of a dosimetry service using electronic dosemeters for individual dose measurements in the UK.

In the United Kingdom it is a legal requirement that the radiation doses received by classified persons are measured using dosemeters that have been provided by an approved dosimetry service. The Health and Safety Executive (HSE) is the regulatory body responsible for approving these dosimetry services. Until recently, statutory dose measurements in the UK have been made with well established dosimetry techniques involving the use of film or TLDs. In January 2000 HSE granted approval to a dosimetry service, operated by a UK nuclear utility, to provide a service to nuclear sites for making measurements of individual dose using electronic dosemeters. HSE has published the requirements that prospective dosimetry services must satisfy in order to gain regulatory approval. These requirements are applicable to those services wishing to use established techniques with film and TLDs and also to services that wish to use novel systems of dose measurement such as electronic dosemeters. This paper briefly describes the regulatory framework for the approval of dosimetry services in the UK, the criteria used by HSE for the approval of these services with particular reference to electronic dosemeters, and the regulatory issues associated with the use of electronic dosemeters for statutory individual dose measurements in the UK.

Consumer Product Safety↗

PubMed2001

Experiences in the determination of activity in thorium contaminated materials in working areas, using gamma spectrometer measurements, from the viewpoint of practical radiation protection.

In industrial processes, classification and clearance of thorium contaminated material is often a time problem. Short-term decisions have to be made about acceptance limits, industrial safety as the workers are in contact with the contaminated material. and the environmental aspect regarding the disposal of the wastes. The use of gamma ray spectrometry measurements is an easy method to estimate the level of activity in materials. Under the precondition of equilibrium of activity within the thorium decay chain, which can be assumed only with knowledge of the materials' history, adequate results can be produced in a reasonable time. The advantages of gamma ray spectrometry are the low investment and operational costs, simple sample preparation, and a system that is relatively quick and easy to operate.

Humans↗