Occupational exposure in Portugal in 1999

This study reports the occupational radiation doses for external exposure received in 1999 by the radiation workers monitored by the Radiological Protection and Nuclear Safety Department (DPRSN) in Portugal. Occupational exposures arise from conventional industry, research laboratories, the health or medical sector, and mining. There are no nuclear power plants in the country. There are two dosimetry systems running simultaneously at DPRSN, one based on film dosimetry and the other on thermoluminescence dosimetry (TLD). In 1999, 8400 persons were monitored, 3100 with film and 5300 with TLD and the data presented in this report were obtained by using both technologies. The annual mean effective doses received from external radiation in the different fields of activity and the distribution of the annual effective dose by dose intervals are presented. The collective annual dose by field of activity is estimated and the contribution to the total annual collective dose is determined.     

Occupational exposure to ionising radiation in the region of Anatolia, Turkey for the period 1995-1999

For this study, the individual annual dose information on classified workers who are occupationally exposed to extended radiation sources in Turkey, was assessed and analysed by the Ankara Nuclear Research and Training Centre dosimetry service at the Turkish Atomic Energy Authority for the years 1995-1999. The radiation workers monitored are divided into three main work sectors: conventional industry (8.24%), medicine (90.20%) and research-education (1.56%). The average annual dose for all workers in each particular sector was 0.14, 0.38 and 0.08 mSv, respectively, in 1995-1999. This paper contains the detailed analysis of occupational exposure. The statistical analysis provided includes the mean annual dose, the collective dose, the distributions of the dose over the different sectors and the number of workers who have exceeded any of the established dose levels.     

Occupational exposure of medical radiation workers in Lithuania, 1950-2003

This study presents the summary of historical exposures, measurementpractice and evolution of the recording of the individual dosesof medical radiation workers during 1950–2003 in Lithuania.The aim of this study is to present occupational exposure ofmedical radiation workers in Lithuania since the earliest appearanceperiod. Data from publications have been used for the earliesttwo periods prior to 1969; data from the archives of the largesthospitals, for the period 1970–1990 and data from LithuanianSubdivision of Individual Dosimetry of Radiation ProtectionCenter, for the period 1991–2003. The analysis of thedata obtained from personal records allows to conclude thatthe average annual effective dose of Lithuanian medical radiationworkers was greatly reduced in radiology, radiotherapy and nuclearmedicine in all occupational categories from 1950 to 2003. Duringthe last period 1991–2003 extremity doses clearly decreasedand after 1994 were no longer present in Lithuania.     

Occupational exposure in Greek industrial radiography laboratories (1996-2003)

More than 40 industrial radiography laboratories are operating in Greece using X-ray or gamma-ray sources and more than 250 workers occupationally exposed to ionising radiation in these facilities are monitored on a regular basis. This study presents the evolution of individual doses received by radiographers during the past years. The mean annual dose (MAD) of all workers as well as of exposed workers is estimated, and correlated to the types of laboratories and practices applied. The MAD of the exposed workers in industrial radiography is compared with the doses of workers in other specialties and with the doses of radiographers in other countries. Furthermore, the study attempts to propose dose constraints for the practices in industrial radiography, according to the BSS European directive and the relevant Greek radiation protection legislation. The proposed value was defined as the dose below which the annual doses of 75% of the exposed radiographers are expected to be included.     

Hand exposure in nuclear medicine workers

As a result of the gamma radiation emitted by radioactive elements (e.g. 99mTc and 131I) used in nuclear medicine laboratories for diagnostic and therapeutic purposes, nuclear medicine workers are exposed to whole-body doses. These doses arc usually measured by using individual film dosemeters. Lead or lead glass shields used during the handling of radioisotopes minimise the whole-body doses received. Nevertheless, part of the job has to be performed manually, hence the hands are more exposed to radiation. This paper presents the results of measuring the equivalent dose to the hands of workers employed in five selected nuclear medicine laboratories where technetium and iodine radioisotopes are in common use. Sixty workers, including physicians, nurses, radiopharmacists and technicians, were included in the study. Doses were measured at 1 month intervals. The study indicated that, in some instances, the danger of radiation dose to the hand may be significant. Monthly doses exceeded 50 mSv, which may suggest that an annual dose may be higher than 500 mSv.     

Occupational exposure to external ionising radiation in Poland, 1999

In 1999 about 6208 radiation workers from 389 departments were monitored by CLOR in Poland. The distribution of annual personal doses shows that 85% of controlled workers received doses below the MDL (0.4 mSv) and about 97% controlled workers received doses below 5 mSv. Doses higher than 50 mSv were received by three operators of industrial radiography units. The radiation workers under control are divided into four main work sectors: nuclear industry, research and education, medicine, and general industry. The average annual dose for all workers in each particular sector was 0.22 mSv, 0.22 mSv, 0.30 mSv and 0.80 mSv, respectively. The average annual dose for the entire monitored population was 0.47 mSv. The average annual dose in each particular sector for number of workers receiving E > 0, i.e. Hp(10) > or = 0.4 mSv, amounted to 1.78 mSv, 2.03 mSv, 1.88 mSv and 4.85 mSv, respectively. The average annual dose for the full number of workers receiving E > 0 was 3.21 mSv. This paper contains the detailed analysis of occupational exposure. The distributions of annual occupational exposure in different work sectors are also given.     

Study of nuclear medicine practices in Portugal from an internal dosimetry perspective

Nuclear medicine practices involve the handling of a wide range of pharmaceuticals labelled with different radionuclides, for diagnostic and therapeutic purposes. This work intends to evaluate the potential risks of internal contamination of nuclear medicine staff in several Portuguese nuclear medicine services and to conclude about the requirement of a routine internal monitoring. A methodology proposed by the International Atomic Energy Agency (IAEA), providing a set of criteria to determine the need, or not, for an internal monitoring programme, was applied. The evaluation of the risk of internal contaminations in a given set of working conditions is based on the type and amount of radionuclides being handled, as well as the safety conditions with which they are manipulated. The application of the IAEA criteria showed that 73.1% of all the workers included in this study should be integrated in a routine monitoring programme for internal contaminations; more specifically, 100% of workers performing radioimmunoassay techniques should be monitored. This study suggests that a routine monitoring programme for internal exposures should be implemented in Portugal for most nuclear medicine workers.     

Task-specific monitoring of nuclear medicine technologists' radiation exposure

Many studies have demonstrated that the exposure of nuclear medicine technologists arises primarily from radioactive patients rather than from preparation of radiopharmaceuticals. However, in order to devise strategies to reduce staff exposure, it is necessary to identify the specific tasks within each procedure that result in the highest radiation doses. An ESM Eberline FH41B-10 radiation dosemeter, which records the ambient dose equivalent rate, was used to monitor the radiation exposure of a technologist and to record the dose rate in microSv per hour every 32 s throughout a working day. The technologist recorded the procedures that were being performed so that the procedures that resulted in higher doses could be identified clearly. The measured doses clearly showed that the major contributions to the technologist's dose were the following: (1) transferring incapacitated patients from the imaging table to a hospital trolley; (2) difficult injections without syringe shields; and (3) setting up patients for gated myocardial scans. The average dose to the technologist from transferring patients after a bone scan was 0.54 microSv, 40% of the total dose of 1.3 microSv for the complete bone scan procedure. The average dose received injecting 900 MBq of 99Tcm-HDP using a tungsten syringe shield was 0.57microSv, but the highest dose was 1.6 microSv, in a patient in whom the injection was difficult. A 0.5 mm lead apron was found to reduce the dose when setting up a patient for a gated stress 99Tcm-sestamibi myocardial scan by approximately a factor of 2. The average dose per patient for this task was reduced from 1.1 to 0.6 microSv. It is recommended that staff waiting for assistance with patient transfers stand away from the patient, that tungsten syringe shields be used for all radiopharmaceutical injections and that a 0.5 mm lead apron be worn when attending patients containing high activities of 99Tcm radiopharmaceuticals, such as those having myocardial imaging.     

Occupational exposure to ionising radiation with thermoluminescence dosimetry system in Turkey, in 2003

The individual annual dose information on classified workers who are occupationally exposed to extended radiation sources by using thermoluminescence dosimetry system, in Turkey, was assessed and analysed by the Ankara Nuclear Research and Training Centre (ANAEM) dosimetry service at the Turkish Atomic Energy Authority (TAEK) for the year 2003. A total of 3721 persons were monitored with TLD and the data presented in this report were obtained by using TLD technology in 2003. The annual mean effective doses received from external radiation in different fields of activities and the distribution of the annual effective dose by dose intervals are presented. The collective annual dose by field of activity is estimated and the contribution to the total annual collective dose is determined.     

Hand exposure to ionising radiation of nuclear medicine workers

The specific nature of work in nuclear medicine departments involves the use of isotopes and handling procedures, which contribute to the considerable value of an equivalent dose received, in particular, by the fingertips. Standard nuclear medicine department uses ring dosemeters placed usually at the base of the middle finger. The main aim of the study was to find out whether a relationship exists between the doses recorded by thermoluminescent detectors placed at various locations on the radiopharmacists' hands and the doses recorded by the ring detectors, and to determine the character of that relationship. The correction factor represents a correction value to be used to calculate the doses which might be received by locations on the hand from the dose recorded by the ring dosemeter. The dose recorded by the ring dosemeter is on the average five times lower than that received by the fingertips of thumb, index and middle fingers.     

Individual monitoring of internal exposure for nuclear medicine workers in Switzerland

Monitoring of internal exposure for nuclear medicine workers requires frequent measurements due to the short physical half-lives of most radionuclides used in this field. The aim of this study was to develop screening measurements performed at the workplace by local staff using standard laboratory instrumentation, to detect whether potential intake has occurred. Such measurements do not enable to determine the committed effective dose, but are adequate to verify that a given threshold is not exceeded. For radioiodine, i.e. (123)I, (124)I, (125)I and (131)I, a calibrated surface contamination monitor is placed in front of the thyroid to detect whether the activity threshold has been exceeded. For radionuclides with very short physical half-lives (≤ 6 h), such as (99m)Tc and those used in positron emission tomography imaging, i.e. (11)C, (15)O, (18)F and (68)Ga, screening procedures consist in performing daily measurements of the ambient dose rate in front of the abdomen. Other gamma emitters used for imaging, i.e. (67)Ga, (111)In and (201)Tl, are measured with a scintillation detector located in front of the thorax. For pure beta emitters, i.e. (90)Y and (169)Er, as well as beta emitters with low-intensity gamma rays, i.e. (153)Sm, (177)Lu, (186)Re and (188)Re, the procedure consists in measuring hand contamination immediately after use. In Switzerland, screening procedures have been adopted by most nuclear medicine services since such measurements enable an acceptable monitoring while taking into account practical and economic considerations.     

Hand exposure of nuclear medicine workers during administration of radioiodine

(131)I has been widely used in nuclear medicine for many years, particularly in the form of iodide for the diagnosis and therapy of thyroid cancer and other thyroid diseases. Manual dispensing of radioiodine-based radiopharmaceuticals results in potentially significant radiation doses to the hands of nuclear medicine personnel performing this task. This article reports the results of thermoluminescent dosemeter-based measurement of radiation doses at various points on the hands of personnel dispensing radioiodine radiopharmaceuticals.     

Extremity exposure in nuclear medicine: preliminary results of a European study

The Work Package 4 of the ORAMED project, a collaborative project (2008-11) supported by the European Commission within its seventh Framework Programme, is concerned with the optimisation of the extremity dosimetry of medical staff in nuclear medicine. To evaluate the extremity doses and dose distributions across the hands of medical staff working in nuclear medicine departments, an extensive measurement programme has been started in 32 nuclear medicine departments in Europe. This was done using a standard protocol recording all relevant information for radiation exposure, i.e. radiation protection devices and tools. This study shows the preliminary results obtained for this measurement campaign. For diagnostic purposes, the two most-used radionuclides were considered: (99m)Tc and (18)F. For therapeutic treatments, Zevalin(?) and DOTATOC (both labelled with (90)Y) were chosen. Large variations of doses were observed across the hands depending on different parameters. Furthermore, this study highlights the importance of the positioning of the extremity dosemeter for a correct estimate of the maximum skin doses.     

Statistical analysis of incidents reported in the Greek Petrochemical Industry for the period 1997-2003

This paper makes an analysis of all reported accidents and incidents in the Greek Petrochemical Industry for the period spanning from 1997 to 2003. The work performed is related to the analysis of important parameters of the incidents, their inclusion in a database adequately designed for the purposes of this analysis and an importance assessment of this reporting scheme. Indeed, various stakeholders have highlighted the importance of a reporting system for industrial accidents and incidents. The European Union has established for this purpose the Major Accident Reporting System (MARS) for the reporting of major accidents in the Member States. However, major accidents are not the only measure that can characterize the safety status of an establishment; neither are the former the only events from which important lessons can be learned. Near misses, industrial incidents without major consequences, as well as occupational accidents could equally supply with important findings the interested analyst, while statistical analysis of these incidents could give significant insight in the understanding and the prevention of similar incidents or major accidents in the future. This analysis could be more significant, if each industrial sector was separately analyzed, as the authors do for the petrochemical sector in the present article.     

Occupational exposure to electromagnetic fields in physiotherapy departments

To assess occupational exposure to electromagnetic fields, 11 microwave (MW), 4 short-wave diathermy and 15 magneto therapy devices were analysed in eight physiotherapy departments. Measurements taken at consoles and environmental mapping showed values above European Directive 2004/40/EC and ACGIH exposure limits at approximately 50 cm from MW applicators (2.45 GHz) and above the Directive magnetic field limit near the diathermy unit (27.12 MHz). Levels in front of MW therapy applicators decreased rapidly with distance and reduction in power; this may not always occur in work environments where nearby metal structures (chairs, couches, etc.) may reflect or perturb electromagnetic fields. Large differences in stray field intensities were found for various MW applicators. Measurements of power density strength around MW electrodes confirmed radiation fields between 30 degrees and 150 degrees , with a peak at 90 degrees , in front of the cylindrical applicator and maximum values between 30 degrees and 150 degrees over the whole range of 180 degrees for the rectangular parabolic applicator. Our results reveal that although most areas show substantially low levels of occupational exposure to electromagnetic fields in physiotherapy units, certain cases of over-occupational exposure limits do exist.     

Occupational exposure in angiography (Prague workplaces)

The results of measurements, which were performed at angiography departments, are presented. The aim of this work was not only to assess patient exposure but also to perform a survey of the occupational exposures of physicians during common angiography examinations of the skull, chest, abdomen and limbs. Patient data, type of examination, fluoroscopy time, the whole number of film frames, dose-area product (Diamentor E) and physician dose (Stephen 6000) were also recorded. There are many factors influencing the level of measured exposures. They include input parameters of X ray performance (kV, mA, projection, diaphragms, ZOOM, type of record etc) and individual approach of the physicians. This paper contributes to the discussion about the increasing exposures of the physicians specialising in diagnostic and interventional angiography.     

Occupational exposure to radiofrequency fields in antenna towers

Exposure of workers to radiofrequency fields was assessed in two medium-sized antenna towers. Towers had transmitting antennas from different networks, e.g. mobile phone networks, radio and digital TV sub-stations and amateur radio. The levels of radiofrequency fields were measured close to the ladders of the towers. All measured values were below ICNIRP occupational reference levels.     

Occupational exposure control: the problem of quantities in radiation protection

The paper explores the quantities and units used in radiation protection with special emphasis on their applications in occupational exposure control. An overview of the current situation reveals that there seem to be too many different quantities associated with the same unit. Some of these quantities are defined in a quite complicated manner and, therefore, may cause some confusion in their interpretation and practical use in the field. Some suggestions towards the simplification of the present system are also proposed.     

Occupational exposures of nuclear power plant workers in Finland

In Finland, the Radiation and Nuclear Safety Authority (STUK) maintains a central dose register where all occupational doses of radiation workers are recorded. The computerised register enables easy control of personal doses, including annual, 5 year and lifetime doses. The type of radiation work is also recorded in the dose register. Finland was one of the first countries in the world to introduce dose limits based on the recommendations of ICRP 60. In this article, the radiation dose data of the Finnish nuclear power plant workers are analysed. The majority of the radiation doses are received during the maintenance outages. The trend of the 5 year doses and their distribution are presented. Doses received during different work assignments were averaged over the years 1996-1999 and they are also discussed in this article.