Collective Effective Dose Research Articles

Safe disassembly and storage of radioactive components of JT-60U torus

Disassembly of the JT-60U torus was started in 2009 after 18 years of D2 operations and was completed in October 2012 for assembling the JT-60SA torus at the same position. The JT-60U torus was featured by the complicated and welded structure against the strong electromagnetic force, and by the radioactivation due to deuterium–deuterium (D–D) reactions. Since this work is the first experience of disassembling a large radioactivated fusion device in Japan, careful preparations of disassembly activities, including treatment of the radioactivated materials and safety work, have been made. During the disassembly period over 3 years, careful measures against exposure were taken and stringent control of exposure dose were implemented, and as a result, accumulated collective effective dose of ∼41,000 person-day to workers was only ∼22mSv in total and no internal exposure was observed. About 13,000 components cut into pieces with measuring the contact dose were removed from the torus hall and stored safely in storage facilities. The total weight of the disassembly components reached up to ∼5400tonnes. Most of the disassembly components will be treated as non-radioactive ones after the clearance level inspection under the Japanese regulations in the future. The assembly of JT-60SA has started in January 2013 after this disassembly of JT-60U torus.

Medical workers operating in nuclear medicine vs PET/CT: Radiation exposure comparison

s / Physica Medica 30 (2014) e16ee44 e31 Background: Long-lived radioactive impurities in radiopharmaceuticals administered at time of calibration usually have minor impact on image quality and the uncertainty of the activity measurement. However, such impurities may result to non-negligible additional radiation burden to patients, personnel, relatives, caregivers and the public, and may trigger innocent alarms in radiation portal monitors. In addition, the presence of certain levels of impurities may impose modifications in waste management policies. The aim of the present study was to identify the most important long-lived impurities, quantify their amount in the patients’ body and address radiation protection issues. Methods and materials: Initial analysis of the radiopharmaceuticals used at the Ioannina University Hospital indicated substantial amounts of longlived (T1/2> 14 d) photon emitting impurities only in 123I-ioflupene (DaTSCAN, GE) and 153Sm-EDMTP (Quadramet, IBA). Spectroscopic analysis of the residuals of at least ten administrations per agent was carried out at least five times per sample. A prototype shadow-shield whole body counter equipped with 16 NaI(Tl) detectors was used to measure the activity present in at least 7 seven patients per agent, 2 to 5 five weeks postadministration. The in vivo activity measurements were coupled with external dose rate measurements using a portable system with spectroscopic capabilities. Results: 121Te, 123Te and 125I were the main photon emitting impurities in 123I-ioflupene, resulting in a median 30 nSv/h external Hp(10) rate and a 3 kBq 121Te body burden. 152Eu, 152Eu and 156Eu were the main impurities in 153Sm-EDMTP, resulting in amedian 300 nSv/h external rate, mainly due to the 152Eu (T1/2:13.5 y) and 154Eu (T1/2:8.6 y) presence in the body, 25 and 33 kBq, respectively. Thus patient and waste management protocols were modified accordingly. Conclusions: Both patient and waste management have to take into account the long-lived impurities present in some of the agents used in daily clinical practice. MEDICAL WORKERS OPERATING IN NUCLEAR MEDICINE VS PET/CT: RADIATION EXPOSURE COMPARISON K. Dalianis , J. Malamitsi , K. Gogos , R. Efthimiadou , J. Andreou , V. Prassopoulos . a PET/CT Department Hygeia SA, Athens, Greece; Medical Physics Laboratory School of Medicine, University of Athens, Greece Purpose: Personnel monitoring results provide information on routine radiation exposure, assist in work planning and allow control of the workplace. The aim of this study was to compare the gamma dose received by dedicated medical workers operating in the first PET/CT department in Greece and also by dedicated medical workers operating in conventional Nuclear Medicine procedures in the same center. PET/CT studies are restricted to the use of 18F fluorodeoxyglucose (FDG). In addition Tc-99m, Tl-201, Ga-67 and I-131 are the radiotracers mostly used in our Nuclear Medicine department. Method: To estimate the effective dose from external exposure, all 9 members of the staff (2 nurses, 2 medical physicists, 5 technologists) had TLD badges worn at the upper pocket of their overall and digital dosimeters worn at the side pocket. Nurses and Medical Physicists also had TLD rings. The nurses and technologists 1,2 are working only in the PET/CT department, while technologists 3,4,5 are operating only in the Nuclear Medicine department covering the most common procedures. Medical Physicists 1,2 are operating in both departments. Results: In the period of January 2013 to December 2013 a total of 982 PET/ CT studies and 2157 conventional Nuclear Medicine procedures were performed. The collective effective and finger doses received by all 4 members of the PET/CT staff were the following: Nurse 1 received 2,94 mSv as a whole body dose and 6,84 mSv as a hand dose and Nurse 2 received 2,87 mSv whole body dose and 5,91 mSv hand dose respectively. Technologists 1 and 2 received 1,95 mSv and 1,56 mSv as the whole body dose respectively. Medical Physicist 1 received 1,75 mSv whole body dose and 7,77 mSv hand dose and Medical Physicist received 2 2,17 mSv and 4,68 mSv respectively. Technologists 3,4 and 5 received 1,85 mSv, 1,76 mSv and 1,82 mSv as whole body doses respectively Conclusion: The personnel dose results are significantly lower than the recommended annual dose by International Commission for Radiological Protection. The higher value of gamma dose for PET/CT workers by comparison with the staff operating conventional Nuclear Medicine procedures is attributable to the higher specific gamma constant of 18F, as well as the longer exposure time required for accurate positioning. THREE-DIMENSIONAL METRICS FOR QUANTITATIVE MONITORING OF TREATMENT EFFECTS WITH PET/CT N. Politis , A. Georgakopoulos , M. Metaxas , S. Chatziioannou , M. Kallergi . Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece; Nuclear Medicine Division, Biomedical Research Foundation of the Academy of Athens, Greece; Nuclear Medicine Section, 2 Department of Radiology, “Attikon” University General Hospital, National and Kapodistrian University of

Occupational exposure recorded before and after new radioprotection regulations

Radioprotection regulations contained a lot of rules and rational explanations in order to protect occupational exposed workers, patients undergoing radioactive procedures and the environment, too. Since radiation harmful effect has been discovered and until today, the radioprotection rules were changed and improved. In Romania the new radioprotection legislation began to emerge in 2000 and in 2002 the first new rules of radioprotection were issued. This paper presents the new radioprotection legislation effect on the doses recorded by the occupational exposures from research area. In this way, it was calculated the annual collective effective dose and individual doses over the period 1990–2000 for workers who activated in nuclear research laboratories and then compared with the similar radiological statistical data obtained over the period 2001–2010, the number of workers on dose range over the studied period. The mean number of workers who recorded doses over minimum detection limit was about 404 from 843 total number, during 1990–2000 and about 170 from 430 researchers, over 2001–2010. It was observed that the individual and collective doses achieved by the workers in the period 1990–1999 were higher than those recorded after 2000.

X-ray population exposure from projection radiology and computed tomography in Emilia-Romagna from 2001 to 2010: comparison of ICRP 60 and ICRP 103 weighting factors

This paper shows the trends from 2001 to 2010 of per caput and collective effective dose (S) to the Emilia-Romagna population due to radiation exposure from projection radiology (PR) and computed tomography (CT), calculated according to both ICRP60 and ICRP103 tissue weighting factors. The frequency of examinations and dose calculations were based on data provided directly by Emilia-Romagna Health Trusts. In particular, effective doses were evaluated using the tissue weighting (w T) factors reported both in ICRP60 (w T,60) and in ICRP103 (w T,103). A decrease in the frequency of PR skull examinations and an increase in the frequency of mammography, CT of the abdomen, chest, and head-neck were found during the decade. In 2010, the PR/CT procedures contributed 75.4%/24.6% to examination frequency and approximately 10%/90% to dose; S was 6,169.2 man Sv when w T,60 was used and 5,855.1-6,665.5 man Sv when w T,103 in two different mathematical models was utilised. Dose estimates pre- and post-ICRP103 must be compared carefully, because changes due to different radiological practices could be confused with changes due to the use of different w T's. In general, dose evaluations with the use of w T,60 until 2007 and w T,103 from 2008 seem to be consistent and coherent.

The maximum angle for the three-dimensional stereo X-ray images formation

The basic method of three-dimensional imaging in radiology is a method of computer tomography. Unfortunately, the increase of amount of the use of computed tomography conduces to the increase of collective effective dose. By the alternative method of three-dimensional imaging, that can be used in a number of cases, there is a method of x-rayed stereoimaging. Except reduction of the patient dose, other advantage of stereoscopic method is the forming of more realistic feeling of three-dimensional depth of the examined object. With the purpose of maximal idea about stereoscopy of the formed image, and more reliable information about sizes and location of separate details in the investigated object, the task of determination of maximal corner of stereoimaging is resolved.References 5, figures 3.

Frequency and Collective Dose of Medical Procedures in Kenya

The first comprehensive national survey on frequency and radiation dose imparted to the population from radiological procedures was carried out in Kenya and reported here. This survey involved assessment of frequency, typical patient radiation exposure, and collective effective dose from general radiography, fluoroscopy, interventional procedures (IPs), mammography, and computed tomography. About 300 x-ray facilities across the country were invited to participate in the survey, and a 31% response was recorded. The individual and collective radiation burdens of more than 62 types of pediatric and adult radiological examinations were quantified using effective and collective dose. The average effective dose for each radiological examination was assessed from the x-ray efficiency performance tests and patient data from over 30 representative radiological facilities. The results found indicated that over 3 million x-ray procedures were performed in 2011, resulting in an annual collective effective dose of 2,157 person-Sv and an annual effective dose per capita of 0.05 mSv. The most frequent examinations were general radiography (94%), computed tomography (3.3%), and fluoroscopy (2.5%). Although the contribution of computed tomography was small in terms of frequency, this procedure accounted for 36% of the effective dose per capita. General radiography was the most frequent type of examination with a contribution of 55% of the effective dose per capita.

Radiation Protection During Decommissioning of the MRT and RFT Material-Research Multi-Loop Reactors at the National Research Center – Kurchatov Institute

Stopped and prepared-for-decommissioning MR and RFT multi-loop materials-research reactors are sources of radiation danger. The radiation protection was optimized to secure radiation safety for workers and the public during decommissioning of the reactors. This lowered significantly the individual and collective effective radiation dose to workers and reduced the number of workers required for radiation-hazardous work.

Estimated collective effective dose to the population from nuclear medicine examinations in Slovenia

BackgroundA national survey of patient exposure from nuclear medicine diagnostic procedures was performed by Slovenian Radiation Protection Administration in order to estimate their contribution to the collective effective dose to the population of Slovenia.MethodsA set of 36 examinations with the highest contributions to the collective effective dose was identified. Data about frequencies and average administered activities of radioisotopes used for those examinations were collected from all nuclear medicine departments in Slovenia. A collective effective dose to the population and an effective dose per capita were estimated from the collected data using dose conversion factors.ResultsThe total collective effective dose to the population from nuclear medicine diagnostic procedures in 2011 was estimated to 102 manSv, giving an effective dose per capita of 0.05 mSv.ConclusionsThe comparison of results of this study with studies performed in other countries indicates that the nuclear medicine providers in Slovenia are well aware of the importance of patient protection measures and of optimisation of procedures.

Exposure of the Swiss population to computed tomography

BackgroundThe frequency of CT procedures has registered a significant increase over the last decade, which led at the international level to an increasing concern on the radiological risk associated with the use of CT especially in paediatrics. This work aimed at investigating the use of computed tomography in Switzerland, following the evolution of CT frequency and dose data over a decade and comparing it to data reported in other countries.MethodsThe frequency and dose data related to CT are obtained by means of a nationwide survey. National frequencies were established by projecting the collected data, using the ratio of the number of CT units belonging to the respondents to the total number of CT units in the country. The effective doses per examination were collected during an auditing campaign.ResultsIn 2008 about 0.8 Million CT procedures (~ 100 CT examinations / 1000 population) were performed in the country, leading to a collective effective dose of more than 6000 man.Sv (0.8 mSv/caput). In a decade the frequency of CT examinations averaged over the population and the associated average effective dose per caput increased by a factor of 2.2 and 2.9 respectively.ConclusionsAlthough the contribution of CT to the total medical X-rays is 6% in terms of the frequency, it represents 68% in terms of the collective effective dose. These results are comparable to those reported in a number of countries in Europe and America with similar health level.

Effect of Geology on Soil Radioactivity and Risks to Humans Based on Data from Several Towns in Nigeria

Gamma ray spectrometric technique has been used to determine activity concentrations of some primordial radionuclides in the naturally occurring uranium, actinium and thorium series and of non-series 40K in soil samples collected from five major towns in Oyo State, Southwestern Nigeria. Activity concentration determination was done using a high purity germanium (HPGe) detector. It ranged from 85.83 ± 4.04 Bq kg−1 to 1,850.60 ± 36.83 Bq kg−1 for 40K; 5.23 ± 0.34 Bq kg−1 to 198.31 ± 4.10 Bq kg−1 for 208Tl (indicator for 232Th) and 7.82 ± 0.42 Bq kg−1 to 64.65 ± 2.00 Bq kg−1 for 214Bi (indicator for 238U). The outdoor absorbed dose rate in air due to each of the primordial radionuclides was calculated from the mean values of the activity concentration in each sample. Values ranged from 3.60 ± 0.17 nGy h−1 to 77.73 ± 1.55 nGy h−1 for 40K, 3.48 ± 0.23 nGy h−1 to 132.07 ± 2.73 nGy h−1 for 208Tl and 3.35 ± 0.21 nGy h−1 to 27.73 ± 0.86 nGy h−1 for 214Bi. The absorbed dose rate in air was the highest for rocky areas, while the lowest value came from non-rocky, non-industrialized areas. The estimated annual outdoor effective dose equivalents for the two rocky areas were 385.76 μSv y−1 and 221.28 μSv y−1. The estimated annual outdoor effective dose equivalents for the two industrialized areas were 64.05 μSv y−1 and 47.65 μSv y−1. The value for non-rocky, non-industrialized areas was 19.19 μSv y−1. The average value for the study area was 147.59 μSv y−1. The estimated collective effective dose equivalent for the area was 9.77 × 102 man-Sv y−1. The expected number of people in the study area at risk of incurring cancer per year as a result of radioactivity in the soil was estimated to be 11; this value represents approximately 7% of the estimated 160 people for 18 Nigerian cities, approximately 69% of 16 people estimated for oil producing areas of Nigeria and less than the United States Environmental Protection Agency regulatory limit of 1 cancer case to 10,000 people. Also, this result shows that local variability of natural radionuclides in soil depends on local geology of the area. The incidence number was 2.4 people per million.

Exposures from nuclear medicine diagnostic procedures: the dose impact on the Aosta Valley population

The present work evaluates the per-procedure, annual collective and per-capita effective doses to the Aosta Valley region population from nuclear medicine (NM) examinations performed from 2005 to 2011 at the regional NM department. Based on its demographical and socioeconomics characteristics, this area can be considered as representative of the level I countries, as defined by the United Nations Scientific Committee on the Effects of Atomic Radiation. The NM per-procedures effective doses were within the range of 0.018-35 mSv. A steady frequency per 10 000 inhabitants has been observed, together with a decrease for thyroid and whole-body bone scintigraphy. Myocardial and bone scintigraphy studies were the major contributors to the total collective effective dose. The mean annual collective and per-capita effective doses to the population were 15 man Sv y(-1) and 120 µSv y(-1), respectively. The NM contribution to the total per-capita effective dose accounts for 5.9 % of that due to the medical ionising radiation examinations overall.

Terrestrial gamma radiation and its statistical relation with geological formation in the Mersing district, Johor, Malaysia

An extensive survey was carried out for gamma dose rates (GDRs) in the Mersing district, Johor, Malaysia. The average value of GDR measured in the district was found to be 140 nGy h(-1), in the range of 40-355 nGy h(-1). The mean weighted dose rate to the population, annual effective dose equivalent, collective effective dose equivalent, lifetime cancer risk were 0.836 mSv y(-1), 0.171 mSv, 1.18 × 10(1) man Sv y(-1) and 6.98 × 10(-4) Sv y, respectively. An isodose map was produced for the district. One way analysis of variance was used to test for differences due to different geological formations present in the Mersing District.

Population Radiation Dose From Diagnostic Nuclear Medicine Procedures in the Tehran Population in 1999–2003

Use of unsealed radiopharmaceuticals in Iran's nuclear medicine centers has expanded rapidly in the last decade. As part of a nationwide survey, this study was undertaken to estimate the radiation risk due to the diagnostic nuclear medicine procedures performed in Tehran in 1999-2003. During the five years of the study, the data of 101,540 yearly examinations of diagnostic nuclear medicine were obtained for 34 (out of 40) active nuclear medicine centers in Tehran. The patients studied were aged 1 y, 5 y, 10 y, 15 y, and adults (>15 y). Compared to an earlier investigation in 1989 (which was published in 1995), striking changes were found to be occurring in the trends of nuclear medicine in Tehran in a matter of a decade. The frequency of cardiac examinations increased from less than 1% in 1989 to 43.2% (mean of 5 y) in 2003; thyroid examinations, with the relative frequency of higher than 80% in 1989, decreased to 26.7% in the current investigation (averaged for 2001); and the number of overall examinations per 1,000 population of Tehran increased from 1.9 in 1989 to 8.8 in this study (about fourfold). The decrease in relative frequency of thyroid examinations could be attributed to the lower referral policy (mainly by specialists), decreased incidence of goiter due to implementation of programs for iodine enrichment diets, introduction of fine needle aspiration (FNA), and sonography techniques for diagnosis of thyroid disease. The large increase in relative frequency of cardiac examinations could be due to the increase in the number of single photon emission computerized tomography (SPECT) systems in recent years as compared to 1989 in Tehran. The collective effective dose increased from 400 (person-Sv) in 1999 to 529 (person-Sv) in 2003, and the effective dose per capita increased from 34.80 μSv in 1999 to 44.06 μSv in 2003 (average, 35.60 μSv).

Interventional Radiology at a Single Institution over 9 Years: A Comprehensive Evaluation of Procedures and an Estimation of Collective Effective Dose

PurposeTo investigate the exposure parameters, effective dose, frequency, and collective dose for interventional radiology (IR) procedures performed at a single institution during a 9-year period. Materials and MethodsAccording to the anatomic region imaged, seven diagnostic and 16 therapeutic IR procedures performed between 2002 and 2010 were retrospectively investigated with regard to exposure setting parameters and frequency. Dose–area products (DAPs), cumulative doses (CDs), and irradiation time values were analyzed on a sample of 1,100 examinations. DAP distributions (median, mean, and percentiles) were adjunctively determined by using bootstrap resampling in PCXMC software to estimate patient effective dose. Data provided by the Radiological Information System allowed collective effective and per-capita doses to obtained. ResultsThe exposure parameters showed widespread variability. The median DAP values for pelvic arteriography and pelvic arterial angioplasty/stent placement were 10,015 and 19,424 cGy·cm2, respectively. For the 23 procedures studied, the estimated average per-procedure effective dose ranged from 0.34 to 104.9 mSv.The pelvis (37%) was the region most often imaged in diagnostic procedures, and angioplasty/stent treatment of vessels was the most frequently performed therapeutic procedure (44%). During the study period, IR procedures increased in frequency (+137%), with a consequent increase in the per-capita dose (0.172 to 0.461 mSv) and collective dose (21 to 58 man-Sv/y). ConclusionsA comprehensive Monte Carlo–aided analysis, which allowed evaluation of contributions in terms of per-procedure and collective doses to the population for the practice of IR, showed a significant growth rate during the study period.

Alteration of medical radiation exposure annual collective effective dose of the population of Tatarstan from 1998 to 2010

Aim. To find out the contemporary principles of collective effective dose of medical radiation formation gained due to medical X-ray and radiological examinations. Methods. Data analysis of radiation and hygiene passports of Republic of Tatarstan territory for the period from 1998 to 2010 was fulfilled. Change of healthcare radiation sources number over time was defined. Number of performed medical X-ray and radiological examinations, average patient’s individual and total effective radiation doses were compared. Results. The number of medical X-ray and radiological examinations increased annually. The rate of different X-ray and radiological examinations as well as gained total effective radiation doses has changed significantly during the analyzed period of time. Use of digital technologies in radiology allowed to decrease average patient’s individual doses to 0.16 mSv for chest photofluorography and to 0.15 mSv for standard X-ray. In recent years, X-ray computed tomography is the largest contribution (40.6%) to the collective effective medical exposure dose of the population. Conclusion. Ionizing radiation use in medical practice remains one of the leading sources of the combined population radiation, primarily due to modern X-ray and radiological examinations; it requires attention and development of special arrangement, technical, prevention measures to decrease unfavorable influence of radiation to population.

Estimation of the collective dose in the Portuguese population due to medical procedures in 2010

In a wide range of medical fields, technological advancements have led to an increase in the average collective dose in national populations worldwide. Periodic estimations of the average collective population dose due to medical exposure is, therefore of utmost importance, and is now mandatory in countries within the European Union (article 12 of EURATOM directive 97/43). Presented in this work is a report on the estimation of the collective dose in the Portuguese population due to nuclear medicine diagnostic procedures and the Top 20 diagnostic radiology examinations, which represent the 20 exams that contribute the most to the total collective dose in diagnostic radiology and interventional procedures in Europe. This work involved the collaboration of a multidisciplinary taskforce comprising representatives of all major Portuguese stakeholders (universities, research institutions, public and private healthcare providers, administrative services of the National Healthcare System, scientific and professional associations and private service providers). This allowed us to gather a comprehensive amount of data necessary for a robust estimation of the collective effective dose to the Portuguese population. The methodology used for data collection and dose estimation was based on European Commission recommendations, as this work was performed in the framework of the European wide Dose Datamed II project. This is the first study estimating the collective dose for the population in Portugal, considering such a wide national coverage and range of procedures and consisting of important baseline reference data. The taskforce intends to continue developing periodic collective dose estimations in the future. The estimated annual average effective dose for the Portuguese population was of 0.080±0.017 mSv caput(-1) for nuclear medicine exams and of 0.96±0.68 mSv caput(-1) for the Top 20 diagnostic radiology exams.

Dose exposure in the ITALUNG trial of lung cancer screening with low-dose CT

Few data are available on the effective dose received by participants in lung cancer screening programmes with low-dose CT (LDCT). We report the collective effective dose delivered to 1406 current or former smokers enrolled in the ITALUNG trial who completed 4 annual LDCT examinations and related further investigations including follow-up LDCT, 2-[(18)F]flu-2-deoxy-d-glucose positron emission tomography (FDG-PET) or CT-guided fine needle aspiration biopsy (FNAB). Using the air CT dose index and Monte Carlo simulations on an anthropomorphic phantom, the whole-body effective dose associated with LDCT was determined for the eight CT scanners used in the trial. A value of 7 mSv was assigned to FDG-PET while the measured mean effective dose of CT-guided FNAB was 1.5 mSv. The mean collective effective dose in the 1406 subjects ranged between 8.75 and 9.36 Sv and the mean effective dose to the single subject over 4 years was between 6.2 and 6.8 mSv (range 1.7-21.5 mSv) according to the cranial-caudal length of the LDCT volume. 77.4% of the dose was owing to annual LDCT and 22.6% to further investigations. Considering the nominal risk coefficients for stochastic effects after exposure to low-dose radiation according to the National Radiological Protection Board, International Commission on Radiological Protection (ICRP) 60, ICRP103 and Biological Effects of Ionizing Radiation VII, the mean number of radiation-induced cancers ranged between 0.12 and 0.33 per 1000 subjects. The individual effective dose to participants in a 4-year lung cancer screening programme with annual LDCT is very low and about one-third of the effective dose that is associated with natural background radiation and diagnostic radiology in the same time period.

Personal dose analysis of TLD glow curve data from individual monitoring records

Radiation exposure of workers in Ghana have been estimated on the basis of personal dose records of the occupationally exposed in medical, industrial and research/teaching practices for the period 2008-09. The estimated effective doses for 2008 are 0.400, 0.495 and 0.426 mSv for medical, industrial and research/teaching practices, respectively. The corresponding collective effective doses are 0.128, 0.044 and 0.017 person-Sv, respectively. Similarly, the effective doses recorded in 2009 are 0.448, 0.545 and 0.388 mSv, respectively with corresponding collective effective doses of 0.108, 0.032 and 0.012 person-Sv, respectively. The study shows that occupational exposure in Ghana is skewed to the lower doses (between 0.001 and 0.500 mSv). A statistical analysis of the effective doses showed no significant difference at p < 0.05 among the means of the effective doses recorded in various practices.

EXPOSURE OF THE SWISS POPULATION BY MEDICAL X-RAYS

Nationwide surveys on radiation dose to the population from medical radiology are recommended in order to follow the trends in population exposure and ensure radiation protection.The last survey in Switzerland was conducted in 1998,and the annual effective dose from medical radiology was estimated to be 1 mSv y j(-1) per capita. The purpose of this work was to follow the trends in diagnostic radiology between 1998 and 2008 in Switzerland and determine the contribution of different modalities and types of examinations to the collective effective dose from medical x-rays. For this reason, an online database(www.raddose.ch) was developed. All healthcare providers who hold a license to run an x-ray unit in the country were invited to participate in the survey. More than 225 examinations, covering eight radiological modalities, were included in the survey. The average effective dose for each examination was reassessed. Data from about 3,500 users were collected (42% response rate). The survey showed that the annual effective dose was 1.2 mSv/capita in 2008. The most frequent examinations are conventional and dental radiographies (88%). The contribution of computed tomography was only 6% in terms of examination frequency but 68% in terms of effective dose. The comparison with other countries showed that the effective dose per capita in Switzerland was in the same range as in other countries with similar healthcare systems, although the annual number of examinations performed in Switzerland was higher.

Radiation doses to the population of the Emilia-Romagna region from medical exposures

The aim of this study was to supplement the analysis of data related to conventional radiography (CR), computed tomography (CT) and nuclear medicine (NM) with those related to interventional radiology (IR), and illustrate the contribution of all these radiological procedures to radiation exposure of the Emilia-Romagna population in Italy. We gathered information about the number and mean doses of 30 interventional procedures performed in 17 hospitals of the Emilia-Romagna region. Seven hospitals were selected, and requests were made for numerical values of the dose-area product (DAP) in various IR procedures measured in the field. From these values, we calculated the 2006 annual collective effective dose (S), per-procedure dose and total dose, as well as the average per-capita dose to the Emilia-Romagna population. The 20 procedures amongst CR, CT, NM and IR that in 2006 contributed the most to Emilia-Romagna population radiation dose are described in detail: CR, CT, NM and IR contribute to approximately 10%, 66%, 9% and 15% of the total dose, and to 70%, 21%, 3% and 6% of procedure frequency, respectively. The S and average per-capita doses were 5,237 person-Sv and 1.2 mSv, respectively. IR procedures deliver high doses to the patient. Therefore, the same attention should be paid to radiation protection as with other high-dose examinations. As IR operators are often not radiologists, special attention should be paid to education in radiation protection of the professionals involved.