Occupational Radiation Protection Research Articles

Review of standards of protection for pregnant workers and their offspring

The recommendations of the International Commission on Radiological Protection and the IAEA Basic Safety Standards (BSS) make clear that the embryo and fetus should be regarded as a member of the public when considering the protection of female workers who are or may be pregnant. The BSS note that the embryo and fetus should be 'afforded the same broad level of protection as required for members of the public'. Similar guidance is included in national legislation in a number of countries. On the basis of a review of such guidance, it was concluded that although the recommendations provided in the BSS are in general agreement with the international consensus on approaches to the protection of pregnant workers and their offspring, more specific supporting guidance is needed. The IAEA is preparing a technical document that extends and clarifies previous advice and considers the practical application of the advice for workers in different types of workplace, for which important potential routes of exposure for the pregnant worker have been identified. This action is being carried out under the framework of the International Action Plan for Occupational Radiation Protection.

Twenty years after the Chernobyl accident: solid cancer incidence in various groups of the Ukrainian population

Several major international studies such as those performed on the A-bomb survivors, have shown a clear linkage between the exposure to ionizing radiation and the occurrence of various cancer types including leukemia. While these studies are mostly characterized by high dose rates, studies on populations exposed after the Chernobyl accident are in most cases characterized by low dose rates which are typical for occupational radiation protection. Here, data on more than 60,000 Ukrainian workers who participated in recovery operation works in Chernobyl in 1986-1987, more than 50,000 evacuees from the city of Prypyat and the 30 km zone, and about 360,000 residents of most contaminated territories are presented, which cover a period of observation from 1980 to 2004. For all cancers combined, statistically significant higher incidence rates than the national rates were found only for the recovery workers (standardized incidence ratio (SIR) 117.2%, 95% confidence interval: 114.1-120.3), while those for the other investigated groups were lower. In all groups under study a significant increase of thyroid cancer incidence rates has been registered. This increase appears to be associated, at least partly, with the fallout of radioiodine, and it was found not only in children, but also in adolescents and adults. For example, the most significant excess was found for male recovery workers corresponding to a factor of 8.0. It is important to keep in mind, however, that the contribution of confounding factors such as an intensified thyroid screening after the Chernobyl accident could not be quantified, in the present study. For female recovery workers there was also an excess of breast cancer over the national rates (SIR 190.6%; 95% confidence interval: 163.6-217.7%). An analysis of the two other groups (evacuees and residents of contaminated territories) gave controversial results: relative to the local standard there was a statistically significant excess, while comparison with the national level did not substantiate this conclusion.

Dose trends in occupational radiation exposure in Europe results from the ESOREX project

The ESOREX project was initiated in 1997 by the EC DG TREN and it was executed by the BfS/Germany in close co-operation with the State Office for Nuclear Safety/Czech Republic). It consists of surveys on radiation monitoring and exposure carried out in the 30 European states. The study provides comparable descriptions of the national administrative structures used to monitor and register individual occupational radiation exposure and the national dose statistics. The analysis of time series about the occupational radiation exposure in different work sectors allows the evaluation of changes and trends after the transposure of the Council Directive 96/29/EURATOM. From 1996 to 2000 occupational radiation protection led partly to substantial dose reductions, primarily in the nuclear sector and in the sector of natural sources. General industry performs less successfully in the reduction of radiation exposure. Work sectors with traditionally low doses like the medical sector or research and education showed less of a reduction. Yet, the dose reductions in these sectors show that even at levels of low exposures there is still room for improvement and dose reduction.

Validation Process and Uncertainty Budget: A Recommended Approach for Performance Verification

Within its Occupational Radiation Protection Programme, the International Atomic Energy Agency (IAEA) initiated and funded many international and regional intercomparison exercises, with the aim of verifying performance of the individual monitoring service providers. An important component within the quality system is the validation and uncertainty budget of the method used. Each method must be validated. This validation process must provide evidence that the method can fulfil all requirements for its intended use. A method may be regarded as validated only when it fulfils all requirements established before the validation process. This paper reviews methods recommended for different types of measurement techniques in individual monitoring.

Intercomparison on Measurements of the Quantity Personal Dose Equivalent Hp(d) in Mixed (Neutron-Gamma) Fields--an IAEA Project

Within its occupational radiation protection programme, the International Atomic Energy Agency (IAEA) initiated and funded an international intercomparison exercise of personal dosemeters to determine the quantity personal dose equivalent in mixed neutron-photon radiation. The objectives of the intercomparison are to assess the capabilities of the dosimetry services in measuring the quantity Hp(10) in mixed neutron-gamma fields; to assist IAEA member states in achieving sufficiently accurate dosimetry; and, if necessary, to provide guidelines for improvements (not simply a test of the performance of the existing dosimetry service). The intercomparison is directed to passive dosemeters to determine, in mixed neutron-gamma radiation fields, either these two components separately or the total personal dose equivalent. The intercomparison consists of two phases: Phase I--Type-test intercomparison: irradiation in selected calibration fields and results used to improve dosimetric procedures of participating laboratories, where needed. Phase II--Simulated workplace field intercomparison: irradiation in radiation fields similar to those in workplaces as a final check of performance. The exercise revealed clear deficiencies in the methodology used by several laboratories and necessitated a detailed analysis of the existing discrepancies. This papers summaries the finding and conclusions for radiation fields similar to those found in nuclear industry.

Occupational Radiation Protection in the Mining and Processing of Raw Materials

1784 Noble Drive NE; Atlanta, GA 30306 (The opinions expressed in this section are those of the authors and do not represent the official opinion or position of the Journal, the Health Physics Society, or the authors’ institutions.)

The impact of the draft 2005 recommendations of ICRP on secondary derived regulatory values being considered by the US Department of Energy

The US Department of Energy, Office of Environment, Safety and Health, Office of Health is responsible for maintaining the Department of Energy's occupational radiation protection rule, Title 10 Code of Federal Regulations, Part 835, Occupational Radiation Protection. The Department of Energy is evaluating amending its rule to include the dose assessment methodology recommended in International Commission on Radiological Protection (ICRP) Publications 60 and 68. On 21 June 2004 the ICRP posted their draft, Recommendations of the International Commission on Radiological Protection 2005, which included revisions to the recommended dose assessment methodology. The Department of Energy compared the draft recommendations to determine their effect on the changes the Department of Energy is currently considering.

Radiation protection guidelines for the practicing orthodontist

This article summarizes the most recent (December 2003) dental x-ray guidelines from the National Council on Radiation Protection and Measurements report #145. The guidelines are intended for all dental health-care providers. They address radiation dose limits for occupational and nonoccupational exposure and radiation protection for operators, patients, and the public. Equipment design can play an important role in radiation protection, and recommendations from the guidelines are discussed.

Occupational Radiation Protection

Occupational Radiation Protection

MARSSIM-based graded approach for posting and controlling areas containing matrixed contamination in soil.

Controlling outdoor areas with radioactive contamination matrixed into the soil presents unique challenges to effective radiological control and environmental restoration programs. These outdoor areas, classified as either soil contamination areas (SCAs) or underground radioactive material areas (URMAs) based on the depth distribution of the contamination, constitute a large portion of the 1,517 km2 (586 mi2) Hanford Site in south-central Washington state. One of the challenges in dealing with these areas is the paucity of regulatory and/or interpretive guidance, particularly with 10 CFR 835, "Occupational Radiation Protection," which does not address SCAs or URMAs. This leads to differing interpretations of applicable regulatory requirements and has caused inconsistency among the programs of various Hanford contractors. To overcome these shortfalls, the Hanford Site Environmental Restoration Contractor (ERC) developed a graded approach for posting and controlling SCAs and URMAs that is based on principles of the Multi-Agency Radiation Survey and Site Investigation Manual. This approach provides an additional degree of worker protection that exceeds the requirements of 10 CFR 835. Each step in this graded approach leads to effective environmental restoration of the Hanford Site.

Biokinetics of iodide in man: refinement of current ICRP dosimetry models.

A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented. The model is developed from published ICRP models. It is designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection. In the proposed model, the distribution of iodide to the thyroid is assumed to be more rapid than in earlier models. Uptakes in stomach wall and salivary glands are considered, and the absorbed doses to these organs calculated. The partitioning of iodide between stomach wall and content is also discussed. Recirculation of organic iodine is also taken into account. Age-dependent half-times for iodide in the thyroid, as well as for organically-bound iodine are presented. The proposed model is applicable for dose estimations with different uptakes in the thyroid as well as for the situation when the thyroid is blocked, completely or incompletely.

Abstract

ICRU Report 47 deals with the measurement of dose equivalents from external photon and electron radiations. This Report provides guidance for the measurement of the operational dose equivalent quantities for neutron radiation, taking into account the recommendations of ICRP Publication 60. The Report addresses occupational neutron radiation protection for the nuclear industry, civil aviation, medical, research and industrial applications. It is directed to readers who need practical advice; it also serves as an introduction into the peculiarities of neutron measurements, describing the principles and methods of neutron measurement.

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.

Quality assurance systems for individual monitoring services.

The International Basic Safety Standards for Protection Against Ionizing Radiation and for the Safety of Radiation Sources (BSS) require, inter alia, the establishment and implementation of quality assurance programmes to ensure that protection and safety requirements are met. The findings and conclusions of the International Conference on Topical Issues in Nuclear and Radiation Safety held in Vienna in 1998 includes, among others, the following recommendation concerning occupational radiation protection: The BSS require a quality assurance (QA) programme to be established as part of radiological protection. Extensive guidance for the development of a QA system is given in reports of ISO and IEC, but further guidance is needed on the interpretation and implementation of these standards. This paper is focused on the available international standards on quality assurance and on the work the IAEA is currently carrying out for their implementation in radiation monitoring services.

Occupational Radiation Protection Dosimetry in Nigeria

The general features of occupational radiation protection dosimetry in Nigeria within the period 1990-1999 have been summarised. About 640 personnel, representing about 25% of the estimated number of radiation workers in Nigeria, were monitored by the TL dosimetry technique during the period, with the majority being the personnel of the teaching hospitals across the country. Most private establishments, especially the X ray diagnostic centres, operate without dosimetry coverage or supervision by a regulatory authority. The weighted mean of the annual effective dose ranged between 0 and 28.97 mSv with the upper limit of collective effective dose being 18.47 man.Sv per year. The individual risk estimate due to this is about 1.5 x 10(-3) per year and this was among the medical personnel. The value could be more if all radiation workers in the country were monitored.

Radiation safety program outcomes as indicated by regulatory compliance activities from 1988 to 1997 in Texas.

Occupational radiation protection programs rarely encounter readily observable workplace injuries or illnesses, so upper management must rely on different indicators of relative performance. In many cases, the number of violations, complaints, and reported incidents is used. As with reported workplace injury and illness data, violation, complaint, and incident data provide only a crude indication of a radiation protection program's overall effectiveness. Even so, it is important to recognize that tangible program outcome measures such as these often dictate management decisions. Hence, safety professionals should have access to baseline violation, complaint, and incident trend data so that more informed preventive strategies can be put into place where possible. To assess the outcomes of radiation protection programs in Texas, data from regulatory compliance activities for a 10-y period, inclusive of calendar years 1988 to 1997, were assembled, summarized, and independently verified. For licensees of radioactive material, the ten most frequently cited violations represented 64% of the total issued during the study period. For registrants of radiation producing devices, the ten most frequently cited violations accounted for 73% of the total. A particular emphasis on proper recordkeeping is evident, and should be noted by any internal radiation protection quality assurance programs. Regardless of the permit type, the vast majority of violations issued were classified as low severity. Licensees were found to be involved in approximately 73% of the incidents recorded, with overexposures and badge overexposures representing the largest identifiable types. Registrants were found to be involved in approximately 57% of the complaints recorded, with the largest identifiable issue being concerns about health care provider qualifications or performance. Although this study was limited to a single state, the results can be of benefit to both quality assurance programs and professional health physics training courses by objectively identifying the areas commonly found to be deficient.

A Method for Evaluating the Adequacy of Workplace Air Sampling and Monitoring Locations

Abstract Current federal guidance on occupational radiation protection recognizes the importance of conducting air flow studies to assist in the placement of air sampling and monitoring equipment. In support of this, Pacific Northwest Laboratory has provided technical assistance to Westinghouse Hanford Company for the purpose of evaluating the adequacy of air sampling and monitoring locations at selected Hanford facilities. Qualitative air flow studies were performed using smoke aerosols to visually determine air movement. Three examples are provided of how air flow studies results, along with information on the purpose of the air sample being collected, were used as a guide in placing the air samplers and monitors. Preparatory steps in conducting an air flow study should include (1) identifying type of work performed in the work area, including any actual or potential release points; (2) determining the amounts of radioactive material available for release and its chemical and physical form; (3) obtainin...

Intérêt et pratique des mesuresin vivopour la réduction de l'exposition du patient et du personnel en radiodiagnostic

This article tries to establish a preliminary accounting of the experience gai­ ned in the use of thermoluminescent dosimetry for occupational and patient radiation protection. An investigation was carried out on all the hospital per­ sonnel and the patients who received X-ray examinations in S hospitals in the Madrid area.

Iodine 131 Therapy Patients: Radiation Dose to Staff

Metastasis to the skeletal system from follicular thyroid carcinoma may be treated with an oral dose of 131I-NaI. Radiation exposures to hospital personnel attending these patients were calculated as a function of administered dose, distance from the patient and time after administration. Routine or emergency patient handling tasks would not exceed occupational radiation protection guidelines for up to 30 min immediately after administration. The emergency handling of several patients presents the potential for exceeding these guidelines.

The Functional and Performance Requirements for Tritium in Air Monitors Provided at CANDU Reactors and Associated Facilities for Occupational Radiation Protection

The functional requirements for fixed tritium in air monitors at CANDU nuclear facilities have recently been revised. The new requirements take into account new facility design, operating experience with monitors, and the need to provide a cost-effective monitoring strategy based on the complementary use of different instrument types. A set of performance requirements for the fixed monitors have been derived which address those characteristics which have a direct bearing on the level of radiation protection provided. To satisfy these performance requirements area-dedicated monitors will be used; i.e. one instrument for each area to be monitored, rather than the centralized multi-area monitoring systems previously employed.