Radiation Protection Dosimetry - Advance Access

RADIOMETRIC SURVEY OF TELETHERAPY TREATMENT ROOMS IN BRAZIL

Thu, 19 Nov 2009 05:12:35 PST

The Brazilian national regulatory authority, National Commission of Nuclear Energy, requires that dose rates in the vicinity of teletherapy treatment rooms do not exceed the permissible limits for workers as well as members of the public, depending on the place considered. At the end of 2005, the Brazilian national regulatory authority reduced the permissible dose limit for controlled areas from 1000 to 400 µSv week^–1. Therefore, the aim of this work is to verify the adequacy of structural shielding to this new limit for telecobalt units that had their sources changed and clinic linear accelerators (ALs) installed before the end of 2005. Considering the ALs, measurements of dose rates in controlled areas did not exceed the new permissible limit, excepting for a single case. In the case of ⁶⁰Co units, a similar situation is observed for controlled areas, although several non-conformities to the limit of uncontrolled area could be observed.

RESEARCH ON EPR MEASUREMENT METHODS OF SUCROSE USED IN RADIATION ACCIDENT DOSE RECONSTRUCTION

Ding, Y., Jiao, L., Zhang, W., Zhou, L., Zhang, X., Zhang, L. — Tue, 17 Nov 2009 03:51:13 PST

Sucrose is a convenient, common, tissue-equivalent material suitable for electron paramagnetic resonance (EPR) dosimetry of ionising radiation. A number of publications have reported on the dosimetric properties of sucrose and their use in radiation accident dose reconstruction. However, previous studies did not include specially the description of measurement methods of sucrose by EPR. The aim of this work is to introduce particularly the EPR measurement methods of sucrose. In this regard, practical considerations of sample size, microwave power, modulation amplitude, EPR spectrum and signal stability are discussed.

RELATION BETWEEN CLINICAL AND LABORATORY PARAMETERS WITH RADIATION DOSE RATES FROM PATIENTS RECEIVING IODINE-131 THERAPY FOR THYROID CARCINOMA

Tue, 17 Nov 2009 03:51:12 PST

Three days following administration of radioactive iodine in 38 patients, exposure rates such as dose rate close to the dress (D0), dose rate of dress at 1 m (D1), dose rate close to the bedsheet (B0), dose rate of bedsheet at 1 m (B1), dose rate of patient at 1 m (P1) and also sum of D1 and B1 (S1) were measured using a radiation detection survey metre with a calibrated ionisation chamber. The patient population consisted of 36 females and 2 males with mean age 38.92 ± 15.76 y. A considerable correlation was found between age and P1 (r = 0.37 and p = 0.02), and administered dose and P1 (r = 0.43 and p = 0.006). It is recommended that a document should be prepared for practitioners and also all individuals coming in contact with older patients are to be made aware of the contamination and radiation hazards.

SPATIAL DISTRIBUTION OF INDOOR RADON IN TRIVENETO (NORTHERN ITALY): A GEOSTATISTICAL APPROACH

Tue, 17 Nov 2009 00:22:05 PST

The study of spatial distribution of the indoor radon has assumed in the last years a lot of interest. The geostatistical techniques turn out to be particularly promising. The present work presents the results of a study where around 4000 indoor radon data from Veneto, Friuli Venezia-Giulia and Alto Adige, collected during the sampling campaigns performed in dwellings and in schools, have been analyzed. After the definition of the common data set, the study of the spatial distribution of the phenomenon has been performed by examining the experimental variograms. Declustering techniques have been applied. Predictive maps were defined by using simulation techniques; they allow to determine the probabilities of exceeding defined concentration levels, the ‘radon-prone’ areas. Systematic results regarding the validation of these maps are reported. This methodological study indicates how it is possible to understand the geographical variability of the phenomenon, trying to find out correlations among indoor radon, geological characteristics (i.e. lithology, morphology, tectonics, soil gas) and building-specific features, which can significantly influence radon concentrations.

Editorial

d'Amore, G. — Fri, 13 Nov 2009 05:18:56 PST

IMPACT OF THE NEW NUCLEAR DECAY DATA OF ICRP PUBLICATION 107 ON INHALATION DOSE COEFFICIENTS FOR WORKERS

Manabe, K., Endo, A., Eckerman, K. F. — Fri, 13 Nov 2009 05:18:56 PST

The impact a revision of nuclear decay data had on dose coefficients was studied using data newly published in ICRP Publication 107 (ICRP 107) and existing data from ICRP Publication 38 (ICRP 38). Committed effective dose coefficients for occupational inhalation of radionuclides were calculated using two sets of decay data with the dose and risk calculation software DCAL for 90 elements, 774 nuclides and 1572 cases. The dose coefficients based on ICRP 107 increased by over 10 % compared with those based on ICRP 38 in 98 cases, and decreased by over 10 % in 54 cases. It was found that the differences in dose coefficients mainly originated from changes in the radiation energy emitted per nuclear transformation. In addition, revisions of the half-lives, radiation types and decay modes also resulted in changes in the dose coefficients.

EXPOSURE ASSESSMENT PROCEDURES IN PRESENCE OF WIDEBAND DIGITAL WIRELESS NETWORKS

Trinchero, D. — Fri, 13 Nov 2009 05:18:55 PST

The article analyses the applicability of traditional methods, as well as recently proposed techniques, to the exposure assessment of electromagnetic field generated by wireless transmitters. As is well known, a correct measurement of the electromagnetic field is conditioned by the complexity of the signal, which requires dedicated instruments or specifically developed extrapolation techniques. Nevertheless, it is also influenced by the typology of the deployment of the transmitting and receiving stations, which varies from network to network. These aspects have been intensively analysed in the literature and several cases of study are available for review. The present article collects the most recent analyses and discusses their applicability to different scenarios, typical of the main wireless networking applications: broadcasting services, mobile cellular networks and data access provisioning infrastructures.

FREQUENCY SELECTIVE SOLUTIONS FOR AN EFFICIENT NON-IONISING RADIATION PROTECTION IN THE RADIOFREQUENCY AND MICROWAVE RANGES

Stefanelli, R., Trinchero, D. — Fri, 13 Nov 2009 05:18:55 PST

The paper introduces an efficient solution for the realisation of frequency-selective devices which can shield non-ionising radiation in the radiofrequency and microwave bandwidths. The identified hardware is transparent to visible light and it can be adapted to the shielding needs, both in terms of frequency and spatial behaviours. Being transparent, it can be effectively applied on windows that normally offer the worst attenuation coefficient to outdoor versus indoor penetration. The solution exhibits enhanced performance, it can be analysed with fast but exact numerical techniques and it can be manufactured by low-cost industrial procedures. To demonstrate the validity of the approach, an example has been designed, analysed and applied to the frequency spectrum occupied by upcoming wideband access base stations.

MACHINE LEARNING FOR THE ANALYSIS OF INDOOR RADON DISTRIBUTION, COMPARED WITH ORDINARY KRIGING

Pegoretti, S., Verdi, L. — Fri, 13 Nov 2009 05:18:54 PST

Having a reliable forecasting tool is necessary to correctly identify radon prone areas, especially in cases where the variable of interest is the indoor radon concentration. An appropriate characterisation of the features of the buildings becomes fundamental. In this work, the results obtained (in global and local scale) using the following approaches for estimating the concentration of indoor radon at locations that were not sampled were compared: geostatistical model, based on ordinary kriging, and machine learning (ML) technique. In the first case, algorithms designed for the specific and fine treatment (by modelling the variographic structure) of the spatial component of the phenomenon were used, whereas in the second case a model that can also exploit information linked to other variables that characterise each single dwelling in which the measure was conducted was used. For locations having large errors, the ML approach provides better results, due to the information related to ‘soil contact’ and ‘building material’.

OUTDOOR RADON CONCENTRATION MEASUREMENTS: SOME CORRELATION WITH MAJOR URBAN POLLUTANTS

Garbero, V., Dellacasa, G., Bianchi, D., Magnoni, M., Erbetta, L. — Tue, 10 Nov 2009 23:25:59 PST

Air pollutants concentration in the urban air strongly depends on the properties of the planetary boundary layer (the lower region of the atmosphere), roughly up to 1 km from Earth's surface. Radioactive radon gas has been recognised by various authors as a valuable natural tracer of transport and dispersion within this layer. To achieve a better comprehension of the urban pollution dynamic in the town of Alessandria, situated in the Po Valley in the north-west of Italy, a system for continuous measurement of radon concentration in outdoor air was experimented. This paper presents the first results obtained: the hourly trend of radon concentration in the diurnal course during different seasons and its correlation with the concentration of the major urban pollutants.

MEASUREMENT OF NATURAL AND ARTIFICIAL RADIOACTIVITY IN POWDERED MILK CONSUMED IN JORDAN AND ESTIMATES OF THE CORRESPONDING ANNUAL EFFECTIVE DOSE

Ababneh, Z. Q., Alyassin, A. M., Aljarrah, K. M., Ababneh, A. M. — Sat, 07 Nov 2009 05:04:01 PST

The activity concentrations of ⁴⁰K, ²²⁶Ra, ²²⁸Ra and ¹³⁷Cs were measured for 14 brands of the powdered milk consumed in Jordan, which are imported from various regions around the world. The activity concentrations of ⁴⁰K were found not to vary greatly from one brand to the other with an average of 348 ± 26 Bq kg^–1. However, the activity concentrations of ¹³⁷Cs revealed a geographical distribution being: (i) undetected in any of the samples from Argentina, (ii) uniformly distributed in samples from Europe with an average of 0.43 ± 0.05 Bq kg^–1, and (iii) widely varying in samples from New Zealand (from being not detected (ND) to 1.55 Bq kg^–1). ²²⁶Ra and ²²⁸Ra were measured above the detection limits in five brands only and displayed relatively low activity concentrations of 0.50–2.14 and 0.78–1.28 Bq kg^–1 for ²²⁶Ra and ²²⁸Ra, respectively. The total average annual effective doses due to intake of ⁴⁰K, ²²⁶Ra, ²²⁸Ra and ¹³⁷Cs from the ingestion of the powdered milk for infants, children and adults were estimated to be (in µSv): 332, 138 and 43, respectively. These results indicate no significant radiation dose to the public.

VALIDATION OF A METHOD FOR NEUTRON DOSIMETRY AND SPECTROMETRY USING NEUTRON ACTIVATION OF METAL DISCS

Sat, 07 Nov 2009 05:04:00 PST

A technique for neutron dosimetry and spectrometry based on neutron activation of different metal discs has been studied. After exposure to a neutron field, the radionuclides produced in the discs are detected using low-level gamma-ray spectrometry and the neutron spectrum is obtained using a spectrum unfolding technique. In order to validate the method, irradiation was performed in a well-characterised ²⁵²Cf neutron reference field. Furthermore, the detector was used to determine the neutron fluence rate and spectrum at a storage place for MOX nuclear fuel. The results of the two measurements are reported and discussed.

Letter to the Editor

Laurier, D., Jacob, S., Laloi, P. — Thu, 05 Nov 2009 05:59:57 PST

THE ACTION PLAN FOR NOISE REDUCTION IN MODENA: METHODS, EFFECTS AND PERSPECTIVES

Campolieti, D., Bertoni, D. — Thu, 05 Nov 2009 05:59:58 PST

Experiences from the action plan concerning noise abatement measures developed in the city of Modena are described. The paper shows noise levels measured after traffic calming measures, after the construction of a noise barrier and a roundabout and after the laying of low-noise pavements. A method for the new action plan design is tested on a large urban area based on a noise map and on a priority index for noise reduction actions taking into account the noise exposure levels and the number of exposed people.

ESTIMATION OF ABSORBED DOSES FROM PAEDIATRIC CONE-BEAM CT SCANS: MOSFET MEASUREMENTS AND MONTE CARLO SIMULATIONS

Kim, S., Yoshizumi, T. T., Toncheva, G., Frush, D. P., Yin, F.-F. — Wed, 04 Nov 2009 06:11:58 PST

The purpose of this study was to establish a dose estimation tool with Monte Carlo (MC) simulations. A 5-y-old paediatric anthropomorphic phantom was computed tomography (CT) scanned to create a voxelised phantom and used as an input for the abdominal cone-beam CT in a BEAMnrc/EGSnrc MC system. An X-ray tube model of the Varian On-Board Imager^® was built in the MC system. To validate the model, the absorbed doses at each organ location for standard-dose and low-dose modes were measured in the physical phantom with MOSFET detectors; effective doses were also calculated. In the results, the MC simulations were comparable to the MOSFET measurements. This voxelised phantom approach could produce a more accurate dose estimation than the stylised phantom method. This model can be easily applied to multi-detector CT dosimetry.

HYDROGEOLOGICAL STUDIES FOR RADIOLOGICAL MONITORING OF SHALLOW GROUNDWATER IN THE EUREX PLANT OF SALUGGIA (VERCELLI, ITALY)

Iezzi, S., Imperi, M., Rosati, M., Ventura, G. — Wed, 04 Nov 2009 06:11:57 PST

In 2004, contaminated water was found inside the safety interspace around the spent fuel pool; therefore, an ample monitoring programme of the structure, soils and shallow groundwater was started in order to detect any radioactive leakage into the environment. A first group of piezometers was installed. In the one nearest to the pool, an anomalous activity of ⁹⁰Sr (~10^–2 Bq l^–1) was found, calling for the following actions: gradual enlarging of the monitoring network, implementation of in situ permeability tests and groundwater tracer test and study of groundwater mobility of the main radionuclides contained in the pool water: ⁹⁰Sr, ¹³⁷Cs, ²⁴¹Am and ^239/240Pu. Because ⁹⁰Sr is the only artificial radionuclide detected in groundwater, this study mainly focused on this one. All the investigations demonstrated that ⁹⁰Sr coming from the pool is not detectable any longer just some tens of metres from the building and allow the correlation of ⁹⁰Sr concentration to flow and water-table fluctuations. Moreover, such a wide mass of hydrogeological and radiological data allows the estimation of an environmental value for environmental radiological significance.

PERSONAL DOSE EQUIVALENT CONVERSION COEFFICIENTS FOR NEUTRON FLUENCE OVER THE ENERGY RANGE OF 20-250 MEV

Olsher, R. H., McLean, T. D., Justus, A. L., Devine, R. T., Gadd, M. S. — Tue, 03 Nov 2009 05:11:23 PST

Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H_p,slab(10,)/, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence ( = 0, 15, 30, 45, 60 and 75°) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom.

IAEA SAFETY SERIES REPORT SERIES: NO. 60: 'RADIATION PROTECTION IN NEWER MEDICAL IMAGING TECHNIQUES: CARDIAC CT' * IAEA SAFETY SERIES REPORT SERIES: NO. 61: 'RADIATION PROTECTION IN NEWER MEDICAL IMAGING TECHNIQUES: CT COLONOGRAPHY'

Banghart, D., Thomas, R. H. — Tue, 03 Nov 2009 05:11:23 PST

CONCENTRATIONS OF 222Rn, 220Rn AND THEIR DECAY PRODUCTS MEASURED IN OUTDOOR AIR IN VARIOUS RURAL ZONES (MOROCCO) BY USING SOLID-STATE NUCLEAR TRACK DETECTORS AND RESULTING RADIATION DOSE TO THE RURAL POPULATIONS

Misdaq, M. A., Amrane, M., Ouguidi, J. — Tue, 03 Nov 2009 05:11:22 PST

Alpha and beta activities per unit volume of air due to radon (²²²Rn), thoron (²²⁰Rn) and their progenies were measured in the outdoor air at different locations in Morocco by using both CR-39 and LR-115 type II solid-state nuclear track detectors (SSNTDs). In addition, the radon concentration was continuously measured in one location by using the methods with SSNTDs and AlphaGuard counter. The influence of the geological and meteorological conditions as well as phosphate and building material dust on the radon concentration in the outdoor air of the areas studied was investigated. The committed equivalent doses due to ²¹⁸Po and ²¹⁴Po radon short-lived progeny were evaluated in different tissues of the respiratory tract of the members of the public from the inhalation of outdoor air. The annual effective dose due to radon short-lived progeny from the inhalation of outdoor air by the members of the rural population was estimated.

IMPACT TO PUBLIC AND ENVIRONMENT OF NORM INDUSTRIES IN ITALY

Trotti, F., Liziero, F., Zampieri, C., De Zolt, S. — Fri, 30 Oct 2009 00:17:51 PDT

Italian legislation requires companies undertaking certain work activities involving naturally occurring radioactive materials (NORM) to check compliance with action levels (1 mSv y^–1 for workers, 0.3 mSv y^–1 for the public). A project is being carried out by ARPAV and other Environmental Agencies to estimate doses to members of the public from NORM from several activities (refractory and tile industry, integrated steelworks, phosphate industry, aluminium production, coal-fired power plants). Activity concentration values of residues have been compared with general clearance levels given in Radiation Protection 122 part 2 and, in several cases, these levels appeared to be exceeded. Doses due to air emissions from stacks, from wastes in disposal sites and from the use of fertilisers in agriculture have been calculated through simulation models (PC-Cream, Resrad, Unscear algorithms), which produce fairly low dose estimates. A major problem for NORM control in Italy at the moment is the lack of official technical and legislative rules (concerning, for instance, residues and effluents management).

PATIENT RADIATION DOSES IN THE MOST COMMON INTERVENTIONAL CARDIOLOGY PROCEDURES IN CROATIA: FIRST RESULTS

Fri, 30 Oct 2009 04:12:12 PDT

Apart from its benefits, the interventional cardiology (IC) is known to generate high radiation doses to patients and medical staff involved. The European Union Medical Exposures Directive 97/43/Euroatom strongly recommend patient dosimetry in interventional radiology, including IC. IC patient radiation doses in four representative IC rooms in Croatia were investigated. Setting reference levels for these procedures have difficulties due to the large difference in procedure complexity. Nevertheless, it is important that some guideline values are available as a benchmark to guide the operators during these potentially high-dose procedures. Local and national diagnostic reference levels (DRLs) were proposed as a guidance. A total of 138 diagnostic (coronary angiography, CA) and 151 therapeutic (PTCA, stenting) procedures were included. Patient irradiation was measured in terms of kerma–area product (KAP), fluoroscopy time (FT) and number of cine-frames (F). KAP was recorded using calibrated KAP-meters. DRLs of KAP, FT and F were calculated as third quartile values rounded up to the integer. Skin doses were assessed on a selected sample of high skin dose procedures, using radiochromic films, and peak skin doses (PSD) were presented. A relative large range of doses in IC was detected. National DRLs were proposed as follows: 32 Gy cm², 6.6 min and 610 frames for CA and 72 Gy cm², 19 min and 1270 frames for PTCA. PSD <1 Gy were measured in 72 % and PSD >2 Gy in 8 % of selected patients. Measuring the patient doses in radiological procedures is required by law, but rarely implemented in Croatia. The doses recorded in the study are acceptable when compared with the literature, but optimisation is possible. The preliminary DRL values proposed may be used as a guideline for local departments, and should be a basis for radiation reduction measures and quality assurance programmes in IC in Croatia.

TANNING LAMPS ULTRAVIOLET EMISSIONS AND COMPLIANCE WITH TECHNICAL STANDARD

Bonino, A., Facta, S., Saudino, S., Anglesio, L., D'Amore, G. — Thu, 29 Oct 2009 23:49:54 PDT

In this work the compliance of tanning lamps with technical standards EN 60335-2-27 ‘Household and similar electrical appliances—Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation’ was analysed. Results of this analysis showed that none of the examined technical documentation produced by the lamps manufacturers is fully compliant with the standard technique. Furthermore data reported in the same manuals, such as effective radiant exposure or irradiance, would indicate that these sources may be the cause of undue exposure to ultraviolet (UV) radiation. For this reason a measurement campaign on UV lamps used in tanning salons was organised. The first results of these measurements seem to confirm the doubts raised from the analysis of the lamp manuals: the use of a tanning lamp can lead to UV radiation exposure levels higher than reference maximum values recommended by EN 60335-2-27.

METHODOLOGICAL AND METROLOGICAL ISSUES IN THE EVALUATION OF NOISE POLLUTION INDICATORS IN RESIDENTIAL ENVIRONMENT

Sepulcri, D. — Thu, 29 Oct 2009 23:49:53 PDT

With regard to differential noise measurements in residential environment, as regulated by Italian law ‘DM 16 marzo '98’, various factors influencing the dispersion of results and measurement uncertainty are taken into account, and some aspects that can weigh on the usefulness of these measurements for compliance assessment are put in evidence.

DEVELOPMENT OF AN ELECTROLYSIS SYSTEM FOR TRITIUM ENRICHMENT IN SUPERFICIAL WATER SAMPLES

Garbarino, G., Magnoni, M., Bertino, S., Losana, M. C. — Wed, 28 Oct 2009 01:11:02 PDT

Tritium present in the environment gradually decreased in the last decades and nowadays it has reached extremely low activity concentrations. The purpose of the present work is the implementation of a tritium enrichment system in water samples using electrolytic techniques and pure nickel and iron electrodes. In the present work a mean tritium enrichment factor of 13.0 ± 3.2 was obtained. This result should allow to reach a minimum detectable activity of tritium in water samples of about 1 tritium unit (TU) or less. The present enrichment system necessitates further adjustments and improvements, such as a cooling system in order to reduce the tritium losses due to evaporation.

DISTRIBUTION OF SOME NATURAL AND MAN-MADE RADIONUCLIDES IN SOIL FROM THE CITY OF VELES (REPUBLIC OF MACEDONIA) AND ITS ENVIRONS

Dimovska, S., Stafilov, T., Sajn, R., Frontasyeva, M. — Wed, 28 Oct 2009 09:27:00 PDT

A systematic study of soil radioactivity in the metallurgical centre of the Republic of Macedonia, the city of Veles and its environs, was carried out. The measurement of the radioactivity was performed in 55 samples from evenly distributed sampling sites. The gross alpha and gross beta radioactivity measurements were made as a screening, using a low background gas-flow proportional counter. For the analysis of ⁴⁰K, ²³⁸U, ²³²Th and ¹³⁷Cs, a P-type coaxial high purity germanium detector was used. The values for the activity concentrations of the natural radionuclides fall well within the worldwide range as reported in the literature. It is shown that the activity of man-made radionuclides, except for ¹³⁷Cs, is below the detection limit. ¹³⁷Cs originated from the atmospheric deposition and present in soil in the activity concentration range of 2–358 Bq kg^–1 is irregularly distributed over the sampled territory owing to the complicated orography of the land. The results of gamma spectrometry are compared to the K, U, and Th concentrations previously obtained by the reactor neutron activation analysis in the same soil samples.

THE DEVELOPMENT OF A GUIDANCE LEVEL FOR PATIENT DOSE FOR CT EXAMINATIONS IN KOREA

Choi, J., Cha, S., Lee, K., Shin, D., Kang, J., Kim, Y., Kim, K., Cho, P. — Wed, 28 Oct 2009 09:26:56 PDT

The primary goal of this study was to analyse the state of patient doses in the field of computed tomography (CT) examinations in the Republic of Korea. All survey data including the CT applications and patient dose details were obtained from general hospitals registered in the Korean Hospital Association. The systematic analysis of the patient dose survey gives target values of the weighted computed tomography dose index (CTDI_w) and the dose–length product (DLP). The targeted CTDI_w values were 69, 69, 31, 19, 44, 25, 24, 20, 2, 19 and 19 mGy for the brain non-contrast enhancement (BNCE), brain contrast enhancement (BCE), neck, chest, spine, liver, pancreas, stomach, kidneys, abdomen routine and abdomen trauma protocols, respectively. The targeted DLP values were 1056, 2112, 762, 1234, 1338, 2794, 2742, 2378, 2836, 1844 and 1939 mGy cm for the BNCE, BCE, neck, chest, spine, liver, pancreas, stomach, kidneys, abdomen routine and abdomen trauma protocols, respectively. Comparing with the EUR recommendation, especially in the DLP, the adjustment of the total scan phase frequency and the shortening of the scan phase in each scan phase are needed to reduce the patients radiation exposure to international standards.

ESTIMATION OF SKIN ENTRANCE DOSES (SEDs) FOR COMMON MEDICAL X-RAY DIAGNOSTIC EXAMINATIONS IN INDIA AND PROPOSED DIAGNOSTIC REFERENCE LEVELS (DRLs)

Sonawane, A. U., Shirva, V. K., Pradhan, A. S. — Wed, 28 Oct 2009 09:26:53 PDT

Skin entrance doses (SEDs) were estimated by carrying out measurements of air kerma from 101 X-ray machines installed in 45 major and selected hospitals in the country by using a silicon detector-based dose Test-O-Meter. 1209 number of air kerma measurements of diagnostic projections for adults have been analysed for seven types of common diagnostic examinations, viz. chest (AP, PA, LAT), lumbar spine (AP, LAT), thoracic spine (AP, LAT), abdomen (AP), pelvis (AP), hip joints (AP) and skull (PA, LAT) for different film-screen combinations. The values of estimated diagnostic reference levels (DRLs) (third quartile values of SEDs) were compared with guidance levels/DRLs of doses published by the IAEA-BSS-Safety Series No. 115, 1996; HPA (NRPB) (2000 and 2005), UK; CRCPD/CDRH (USA), European Commission and other national values. The values of DRLs obtained in this study are comparable with the values published by the IAEA-BSS-115 (1996); HPA (NRPB) (2000 and 2005) UK; EC and CRCPD/CDRH, USA including values obtained in previous studies in India.

MEASUREMENT OF ELECTROMAGNETIC FIELDS GENERATED BY AIR TRAFFIC CONTROL RADAR SYSTEMS WITH SPECTRUM ANALYSERS

Barellini, A., Bogi, L., Licitra, G., Silvi, A. M., Zari, A. — Wed, 28 Oct 2009 01:11:01 PDT

Air traffic control (ATC) primary radars are ‘classical’ radars that use echoes of radiofrequency (RF) pulses from aircraft to determine their position. High-power RF pulses radiated from radar antennas may produce high electromagnetic field levels in the surrounding area. Measurement of electromagnetic fields produced by RF-pulsed radar by means of a swept-tuned spectrum analyser are investigated here. Measurements have been carried out both in the laboratory and in situ on signals generated by an ATC primary radar.

MICROSCALE MODELLING SIMULATIONS FOR THE SITE CHARACTERIZATION OF AIR QUALITY STATIONS IN AN URBAN ENVIRONMENT

Tinarelli, G., Piersanti, A., Radice, P., Clemente, M., De Maria, R. — Wed, 28 Oct 2009 01:10:58 PDT

The presence of natural or artificial barriers placed near the air quality measuring stations located in an urban environment poses some problems in the assessment of their siting and significance. The atmospheric flow distortion induced by these structures can create situations that affect the concentration levels of measured pollutants. A modelling study at microscale of the pollutant dispersion in an urban environment has been performed to quantify these possible effects on measurements. The target domain is located in a central section of the city of Turin (northern Italy) around via della Consolata, near the location of an existing station of the regional monitoring network. The study involved the use of the modelling system Micro-Swift–Spray, which takes into account the presence of complex topographical barriers, including street canyons and squares surrounded by buildings. Two entire days have been simulated, to characterise both a critical and a more standard condition, with reconstruction of average flow, turbulence and hourly ground-level pollutant concentrations. Contributions from both traffic and building-heating sources have been considered and a comparison with measured concentrations has been performed to verify the representativeness of the measuring station with respect to both average conditions and spatial variability inside the considered region, otherwise very difficult to asses through a single and isolated measuring point.

INFLUENCE OF A CEMENT INDUSTRY ON THE FINE AND ULTRAFINE PARTICLES COMPOSITION IN A RURAL AREA

Wed, 28 Oct 2009 01:10:55 PDT

The cement industry of this work is located in the Fumane valley, in the north of Verona. The environmental impact of the air emissions from the plant was studied using different methods: the characterisation of the raw materials utilised in the production process and of the emissions from the chimney of the clinker kiln; the sampling of the air particles on filter in the region around the plant; the biomonitoring using transplanted mosses; the study of the air pollution dispersion using a model.

CHARACTERISATION AND MEASUREMENT OF SIGNALS GENERATED BY DVB-H 'GAP-FILLER' REPEATERS

Baldini, M., Barellini, A., Bogi, L., Licitra, G., Silvi, A. M., Zari, A. — Mon, 26 Oct 2009 03:30:41 PDT

DVB-H (Digital Video Broadcasting Handheld) is the standard developed by DVB Project and approved by ETSI with the aim of providing the reception of DVB signals even in mobility but also data transfers and multimedia services. The introduction and development of the DVB-H system is still ongoing. In this context, this work focuses on the temporal trend of electromagnetic impact of an urban DVB-H repeater (called ‘gap-filler’) for exposure assessment purposes; it also describes a method for its measurement by means of narrow band instrumental chains.

ANALYSIS OF CRITICAL SITUATIONS IN THE EVALUATION OF HUMAN EXPOSURE TO MAGNETIC FIELDS WITH COMPLEX WAVEFORMS

Crotti, G., Giordano, D. — Fri, 23 Oct 2009 06:52:41 PDT

The paper analyses some critical situations in the assessment of the compliance with the human exposure limits to the low-frequency magnetic fields. The study is focused on non-sinusoidal and transient waveforms in the frequency range from 8 Hz to 65 kHz. It is carried out by combining measurements and numerical evaluations, starting from actual magnetic flux density behaviours. The results show that inconsistent indications of compliance with the exposure limits may arise not only because of the evaluation method adopted, but also as a result of the used time or frequency windows in relation to the investigated magnetic field waveform.

SUPERFICIAL GROUNDWATER CONTAMINATION BY ARTIFICIAL RADIONUCLIDES BY THE NUCLEAR SITE OF SALUGGIA (VERCELLI, ITALY): RADIOLOGICAL MONITORING ACTIVITIES

Porzio, L. — Thu, 22 Oct 2009 07:21:35 PDT

During the last 15 y, by the Saluggia (Vercelli, Italy) nuclear site, episodes of contamination of the superficial groundwater happened due to artificial radionuclides. The local network of radiological monitoring around the nuclear site, managed by Arpa Piemonte from the late 1980s, highlighted the presence of ⁶⁰Co, ⁹⁰Sr, ¹³⁷Cs and ³H during this period. The object of this paper was to give particular evidence not to analytical aspects, but to the methodical approach used to solve the problems that arose. In fact, the intrinsic hydro-geological vulnerability of the zone, the typology and conditions of the plants (all very old) and the presence of the 'Acquedotto del Monferrato' tap water well field, one of the most important in Piemonte, at ~2 km downstream of the site, made the situation very difficult to approach.

ON THE USE OF ADVANCED NUMERICAL MODELS FOR THE EVALUATION OF DOSIMETRIC PARAMETERS AND THE VERIFICATION OF EXPOSURE LIMITS AT WORKPLACE

Catarinucci, L., Tarricone, L. — Wed, 21 Oct 2009 00:26:39 PDT

With the next transposition of the 2004/40/EC Directive, employers will become responsible for the electromagnetic field level at the workplace. To make this task easier, the scientific community is compiling practical guidelines to be followed. This work aims at enriching such guidelines, especially for the dosimetric issues. More specifically, some critical aspects related to the application of numerical dosimetric techniques for the verification of the safety limit compliance have been highlighted. In particular, three different aspects have been considered: the dosimetric parameter dependence on the shape and the inner characterisation of the exposed subject as well as on the numerical algorithm used, and the correlation between reference limits and basic restriction. Results and discussions demonstrate how, even by using sophisticated numerical techniques, in some cases a complex interpretation of the result is mandatory.

METHODS FOR SPECTRAL INTERFERENCE CORRECTIONS FOR DIRECT MEASUREMENTS OF 234U AND 230Th IN MATERIALS BY GAMMA-RAY SPECTROMETRY

Yucel, H., Solmaz, A. N., Kose, E., Bor, D. — Tue, 20 Oct 2009 03:07:18 PDT

When the high-resolution gamma-ray spectrometry was used in the analysis of ²³⁴U and ²³⁰Th in samples, there is a much more need to correct for the measured activity results of ²³⁴U and ²³⁰Th mainly due to self-absorption effects and the interfering lines from ²²⁶Ra, ²³⁵U, ²³⁸U and their decay products that often might be present in the samples. Therefore, in the present study, the methods for the spectral interference corrections for the analytical peaks of ²³⁴U and ²³⁰Th are suggested to take into account the contributions of the overlapping gamma rays to these peaks. For the method validation, direct gamma-ray spectrometric measurements were carried out using certified reference materials (CRM) by use of a 76.5 % n-type Ge detector. The activities measured for the CRM samples were corrected for spectral interferences, self-absorption and true coincidence-summing (TCS) effects. The obtained results indicate that ignoring of the contribution of the interference gamma rays to the main analytical peak at 53.2 keV of ²³⁴U leads to a lager systematic error of 87.3–90.4 % for the measured activities of ²³⁴U, and similarly if one ignores the contributions of the interference gamma rays to the main analytical peak at 67.7 keV of ²³⁰Th, this leads to a much smaller systematic error of 2.1–2.7 % for the activities of ²³⁰Th. Therefore, the required correction factors for spectral interferences to the analytical peaks of ²³⁴U and ²³⁰Th are not negligible and thus they should also be considered besides necessary self-absorption factors to determine more accurate activities in the samples. On the other hand, it is estimated that although the TCS effects on the main analytical peaks of both ²³⁴U and ²³⁰Th are negligibly small, those TCS correction factors for their interference gamma rays to these peaks should be taken into account when direct measurements are performed in a close-counting geometry condition. Otherwise, the resulted activities can have serious erroneous results for both ²³⁴U and ²³⁰Th while using gamma-ray spectrometry, thereby leading to inaccuracies in their derived quantities, for instance, the corresponding age determinations of the samples.

MODIS AND OMI SATELLITE OBSERVATIONS SUPPORTING AIR QUALITY MONITORING

Tue, 20 Oct 2009 00:27:47 PDT

Within the framework of air quality monitoring, measurements by Earth-observing satellite sensors are combined here with regional meteorological and chemical transport models. Two satellite-derived products developed within the QUITSAT project, regarding significant pollutants including PM_2.5 and NO₂, are presented. Estimates of PM_2.5 concentrations at ground level were obtained using moderate resolution imaging spectroradiometer (Terra-Aqua/NASA) aerosol optical properties. The semi-empirical approach adopted takes into account PM_2.5 sampling and meteorological descriptions of the area studied, as simulated by MM5, to infer aerosol optical properties to PM projection coefficients. Daily maps of satellite-based PM_2.5 concentrations over northern Italy are derived. Monthly average values were compared with in situ PM_2.5 samplings showing good agreement. Ozone monitoring instrument (OMI) (Aura/NASA) NO₂ tropospheric contents are merged using the GAMES chemical model simulations. The method employs a weighted rescaling of the model column in the troposphere according to the OMI observations. The weightings take into account measurement errors and model column variances within the satellite ground pixel. The obtained ground-level concentrations of NO₂ show good agreement with the environmental agencies' in situ.

What is radiation protection dosimetry?

McDonald, J. C. — Tue, 20 Oct 2009 00:27:45 PDT

URBAN EXPOSURE TO ELF MAGNETIC FIELD DUE TO HIGH-, MEDIUM- AND LOW-VOLTAGE ELECTRICITY SUPPLY NETWORKS

Bottura, V., Cappio Borlino, M., Carta, N., Cerise, L., Imperial, E. — Tue, 20 Oct 2009 00:27:44 PDT

The regional environment protection agency (ARPA) of the Aosta Valley region in north Italy performed a survey of magnetic field triggered by the power supply network in high, medium and low voltages on the entire area of Aosta town. The electrical distribution system for houses was not however taken into account. The aim of the survey was to evaluate the global population exposure and not simply the assessment of the legal exposure limit compliance.

STUDY OF ATMOSPHERIC AEROSOLS AND MIXING LAYER BY LIDAR

Angelini, F., Barnaba, F., Landi, T. C., Caporaso, L., Gobbi, G. P. — Tue, 20 Oct 2009 00:27:43 PDT

The LIDAR (laser radar) is an active remote sensing technique, which allows for the altitude-resolved observation of several atmospheric constituents. A typical application is the measurement of the vertically resolved aerosol optical properties. By using aerosol particles as a marker, continuous determination of the mixing layer height (MLH) can also be obtained by LIDAR. Some examples of aerosol extinction coefficient profiles and MLH extracted from a 1-year LIDAR data set collected in Milan (Italy) are discussed and validated against in situ data (from a balloon-borne optical particle counter). Finally a comparison of the observation-based MLH with relevant numerical simulations (mesoscale model MM5) is provided.

INTERCOMPARISON OF MAGNETIC FIELD MEASUREMENTS NEAR MV/LV TRANSFORMER SUBSTATIONS: METHODOLOGICAL PLANNING AND RESULTS

Violanti, S., Fraschetta, M., Adda, S., Caputo, E. — Tue, 20 Oct 2009 00:27:43 PDT

Within the framework of Environmental Agencies system's activities, coordinated by ISPRA (superior institute for environmental protection and research), a comparison among measurements was designed and accomplished, in order to go into depth on the matter of measurement problems and to evaluate magnetic field at power frequencies. These measurements have been taken near medium voltage /low voltage transformer substation. This project was developed with the contribution of several experts who belong to different Regional Agencies. In three of these regions, substations having specific international standard characteristics were chosen; then a measurement and data analysis protocol was arranged. Data analysis showed a good level of coherence among results obtained by different laboratories. However, a range of problems emerged, either during the protocol predisposition and definition of the data analysis procedure or during the execution of measures and data reprocessing, because of the spatial and temporal variability of magnetic field. These problems represent elements of particular interest in determining a correct measurement methodology, whose purpose is the comparison with limits of exposure, attention values and quality targets.

QUANTITATIVE EVALUATION OF PERSONAL EXPOSURE TO UV RADIATION OF WORKERS AND GENERAL PUBLIC

Sisto, R., Borra, M., Casale, G. R., Militello, A., Siani, A. M. — Mon, 19 Oct 2009 04:21:18 PDT

Due to meteorological conditions variability and to the variability of exposure patterns, which can be largely different during a working day, personal dosemeters use can be necessary to obtain a correct quantitative evaluation of the radiation dose absorbed by an exposed worker. Different classes of personal dosemeters exist and, among them, electronic dosemeters and polysulphone film dosemeters. An experimental campaign is presented conduced in a cultivated area of Tuscany and some aspects are discussed about an experimental campaign performed on a population of volunteers on a central Italy beach near Rome. The aim of the present work is to show some relevant issues in a dosimetric approach to the exposure evaluation of outdoor workers and, in general, of the public during recreational activities.

REVIEW OF OPEN PROBLEMS IN ASSESSING COMPLIANCE WITH 2004/40/EC DIRECTIVE EXPOSURE LIMIT VALUES FOR LOW-FREQUENCY CURRENT DENSITY BY MEANS OF NUMERICAL TECHNIQUES

Zoppetti, N., Andreuccetti, D. — Mon, 19 Oct 2009 04:21:17 PDT

The endorsement process of the 2004/40/EC Directive (still in progress) has led to a critical analysis of the ICNIRP Guidelines, on which the directive is based. In particular, some known problems affect the applicability of the numerical techniques needed for checking compliance with limits at low frequency. A review of these open problems is presented in the paper, highlighting how such problems deal more with pre-processing and post-processing steps than with the core numerical calculation of the current density.

MANAGEMENT OF NORM-CONTAINING PROCESSING RESIDUALS FROM HYDROCARBONS EXTRACTION AND TREATMENT PLANTS

Mon, 19 Oct 2009 04:21:16 PDT

Eni, in collaboration with ARPA Veneto, laid down a procedure for the exposure assessment of workers and the public to natural radionuclides contained in oil sludge during their future removal from hydrocarbons extraction and treatment plants. Reference legislation for this study is Italian Legislative Decree 241/00, which regulates protection from exposure to ionising radiation also for working activities with naturally occurring radioactive materials.

A SIMPLIFIED PROCEDURE FOR DOSIMETRIC EVALUATIONS ON ELF SOURCES WITH COMPLEX WAVEFORMS

Andreuccetti, D., Priori, S., Zoppetti, N. — Mon, 19 Oct 2009 04:21:16 PDT

The endorsement of the 2004/40 European Directive has renewed the interest in numerical electromagnetic dosimetry. In this field, a need is clearly perceived for dosimetric approaches able to reduce costs and the time necessary for this type of evaluations. In the low and intermediate frequency ranges, EM dosimetry makes use of quasi-static techniques in the frequency domain, which become onerous when dealing with sources emitting multiple frequencies. A procedure is then proposed, able to greatly simplify the numerical process needed to perform a dosimetric calculation involving a complex waveform. The procedure is based on the use of an ‘equivalent’ field intensity at an arbitrarily chosen ‘reference’ frequency and allows executing a single-frequency dosimetric evaluation able to take into account, with some approximations, the complete spectral contents of the source signal.

RADON MONITORING IN WATER SOURCES OF BALAKOT AND MANSEHRA CITIES LYING ON A GEOLOGICAL FAULT LINE

Khan, F., Ali, N., Khan, E. U., Khattak, N. U., Khan, K. — Mon, 19 Oct 2009 05:08:28 PDT

This paper relates to a series of systematic studies regarding measurement of radon concentration in the earthquake-affected areas of northern Pakistan. Radon is a radioactive -particle-emitting gas originating from the decay series of uranium and thorium and is found anywhere in soil, air and water. The nature of water does not matter with regard to the presence of radon, however, the level of radon concentration varies in different types of water. The present survey is carried out in water samples from the fault zone of Balakot and Mansehra regions, North West Frontier Province, Pakistan, which is important for geological consideration and protection from radiation hazards. The measurements were made on a Pylon system that is based on the radon gas measurement with a Lucas cell. In 72 water samples in the equilibrium state between radon and its progeny, the concentration level of radon is measured. The results show that the radon concentrations are in the range of 4.99–24.52 kBq/m³, with an average value of 15.52 kBq/m³ for all types of water taken in this survey.

NOISE MODEL APPLICATION TO SMALL HYDROELECTRICAL POWER PLANTS IMPACT EVALUATION IN THE AOSTA VALLEY TERRITORY

Tibone, C., Agnesod, G., Cappio Borlino, M., Tartin, C., Crea, D., Berlier, F. — Mon, 19 Oct 2009 05:08:26 PDT

In this paper measurements, results and model estimates, with reference to hydroelectric power plant noise emissions in the Aosta Valley territory, are compared in different contexts. The analysis was performed to evaluate and point out the influence of the noise source context on the accuracy of the model results. The estimates were implemented considering power plants as: point sources and area sources taking (or not) into account the building elements of the plant. This method allowed evaluating the detail that is suitable to achieve in an estimate and to justify possible simplifications in this kind of noise source description. Noise measurements were carried out simultaneously, at different distances from the power plants that were taken into account. The measurement results at the closest points to the sources were used as the model input data, while the levels found at the other points were used for comparison with the estimate results.

NOISE ACTION PLAN OF AGGLOMERATIONS: SUSTAINABLE HYPOTHESIS OR UTOPY?

Magri, S. L., Masera, S., Fogola, J. — Mon, 19 Oct 2009 04:21:15 PDT

European and Italian laws establish that agglomerations of more than 100 000 inhabitants must adopt an action plan in order to manage noise issues and effects. The plan aim is to reduce population exposure to environmental noise, which is defined as the outdoor sound created by human activities, including noise emitted by road traffic, rail traffic and air traffic, and noise from sites of industrial activity. Although acoustic pollution represents one of the main causes of annoyance for inhabitants of urban areas, the political agenda does not acknowledge it among the main environmental issues. Thus, acoustic reclamation is often considered a duty to be accomplished rather than a way to improve quality of life for citizens. Furthermore, financial resources are generally very poor while the acoustic critical situations are numerous and serious in terms of exceeding the limit. In this situation, what is the meaning of an urban area noise action plan? What are the concrete actions that municipalities can realise to reduce urban noise pollution? This study tries to answer these questions, starting from the analysis carried out for the action plan of the city of Turin.

Letter to the Editor

Korblein, A., Fairlie, I. — Mon, 19 Oct 2009 05:08:23 PDT

GAMMA SPECTROSCOPIC ANALYSIS AND ASSOCIATED RADIATION HAZARDS OF BUILDING MATERIALS USED IN EGYPT

El-Taher, A. — Mon, 19 Oct 2009 05:08:22 PDT

Radiation exposure of the population can be increased appreciably by the use of building materials containing above-normal levels of naturally occurring radionuclides of terrestrial origin. Using -ray spectrometry, the natural radioactivity levels of 55 samples of natural and manufactured Egyptian building materials have been investigated. The samples were collected from local market and construction sites. From the measured -ray spectra, activity concentrations were determined. The activities were in the ranges 11.7–35.6, 12.4–55.2 and 60–350 Bq kg^–1 for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The activities are compared with available reported data from other countries and with the world average value for soils. The radium equivalent activity Ra_eq, the external hazard index H_ex and the absorbed dose rate in air D in each sample was evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. All building materials have shown Ra_eq (range from 37.76 to 116.87 Bq kg^–1) lower than the limit of 370 Bq kg^–1 adopted by the Organization for Economic Cooperation and Development (OECD). The absorbed dose rate in indoor air is lower than the international recommended value of 55 nGy h^–1 for all test samples. All the materials examined are acceptable for use as building materials as defined by the OECD criterion.

A STATE INDICATOR ON REGIONAL SCALE FOR HIGH-VOLTAGE POWER LINES: DEFINING A PRIORITY FOR IN SITU INSPECTIONS

Comelli, M., Colonna, N., Martini, L., Licitra, G. — Fri, 16 Oct 2009 00:05:00 PDT

An integrated system to evaluate the magnetic field generated by power lines exposure has been developed using a specific simulation model (PLEIA-EMF). This is part of a software toolset, subjected to internal suitability verifications and in-field validations. A state indicator related to each span has been determined using the data extracted from digital cartography, the magnetic field calculated by PLEIA and the number of people living in the nearest buildings. In this way, it is possible to determine eventual criticalities in the considered area, focusing attention on those cases with more considerable exposure levels and involving a higher number of people. A campaign of inspections has been planned using PLEIA simulations. The reliability of stored technical data and the real population exposure levels have been evaluated in critical cases, individuated through the following described methodology. The procedures leading to the indicator determination and the modalities of in situ inspections are here presented.

RADIATIVE MODELS FOR THE EVALUATION OF THE UV RADIATION AT THE GROUND

Koepke, P. — Wed, 14 Oct 2009 08:04:24 PDT

The variety of radiative models for solar UV radiation is discussed. For the evaluation of measured UV radiation at the ground the basic problem is the availability of actual values of the atmospheric parameters that influence the UV radiation. The largest uncertainties are due to clouds and aerosol, which are highly variable. In the case of tilted receivers, like the human skin for most orientations, and for conditions like a street canyon or tree shadow, besides the classical radiative transfer in the atmosphere additional modelling is necessary.

ACOUSTIC SURVEY OF QUIET AREAS AND LONG-RANGE ANTHROPOGENIC NOISE

Conte, A., Balzano, M. — Wed, 14 Oct 2009 08:04:24 PDT

The enforcement of legislative decree 194/2005 presupposes the acoustic characterisation of ‘quiet areas’ both inside and outside urban centres, which are consistent with preservation and reclamation. This topic is currently studied, focusing on monitoring techniques, on the impact on fauna and on human use of such areas. The Province of Genoa, Italy, is implementing a project on the acoustic characterisation of ‘sample’ quiet areas, with the objective of developing evaluation methods of the acoustic quality and, from a more general viewpoint, of anthropogenic noise impact.

INDOOR RADON CONCENTRATION MEASUREMENT IN THE DWELLINGS OF DISTRICT POONCH (AZAD KASHMIR), PAKISTAN

Wed, 14 Oct 2009 08:04:23 PDT

The present study deals with measurement of indoor radon concentrations in dwellings of the district Poonch of the state of Azad Jammu and Kashmir, Pakistan. In this context, CR-39-based box-type radon detectors were installed in drawing rooms and bedrooms of 80 selected houses and were exposed to indoor radon for 3 months. After exposure, the CR-39 detectors were etched for 9 h in 6 mol NaOH at 70°C and the observed track densities were related to radon concentrations. Measured indoor radon concentrations in the studied area ranged from 27 ± 6 to 169 ± 4, 29 ± 6 to 196 ± 4 and 31 ± 5 to 142 ± 2 Bq m^–3 in the drawing rooms and 74 ± 5 to 172 ± 3, 32 ± 6 to 191 ± 4 and 27 ± 5 to 155 ± 2 Bq m^–3 in bedrooms of the Abbaspur, Hajira and Rawalakot regions of the district Poonch, respectively; whereas weighted average radon concentration ranged from 93 ± 6 to 159 ± 4, 33 ± 5 to 118 ± 3 and 31 ± 6 to 155 ± 5 Bq m^–3 in the dwellings of Abbaspur, Hajira and Rawalakot, respectively. Estimated doses due to the indoor radon ranged from 2.35 ± 0.15 to 4.00 ± 0.10, 0.83 ± 0.08 to 2.98 ± 0.08 and 0.78 ± 0.15 to 3.91 ± 0.13 mSv y^–1 for Abbaspur, Rawalakot and Hajira, respectively. Comparing the current indoor radon results with those of the Health Protection Agency UK and US EPA (i.e. 200 and 148 Bq m^–3) limits, majority of the houses surveyed in the present study are within the safe limits.

THE RBE OF 3.4 MeV {alpha}-PARTICLES AND 0.565 MeV NEUTRONS RELATIVE TO 60Co {gamma}-RAYS FOR NEOPLASTIC TRANSFORMATION OF HUMAN HYBRID CELLS AND THE IMPACT OF CULTURE CONDITIONS

Wed, 14 Oct 2009 08:04:20 PDT

The neoplastic transformation of human hybrid CGL1 cells is affected by perturbations from external influences such as serum batch and concentration, the number of medium changes during the 21-day expression period and cell seeding density. Nevertheless, for doses up to 1.5 Gy, published transformation frequencies for low linear energy transfer (LET) radiations (-rays, MeV electrons or photons) are in good agreement, whereas for higher doses larger variations are reported. The ⁶⁰Co -ray data here for doses up to 1.5 Gy, using a low-yield serum batch and only one medium change, are in agreement with published frequencies of neoplastic transformation of human hybrid cells. For 3.4 MeV -particles (LET = 124 keV/µm) and 0.565 MeV monoenergetic neutrons relative to low doses of ⁶⁰Co -rays, a maximum relative biological effectiveness (RBE_M) of 2.8 ± 0.2 and 1.5 ± 0.2, respectively, was calculated. Surprisingly, at higher doses of ⁶⁰Co -rays lower frequencies of neoplastic transformation were observed. This non-monotonic dose relationship for neoplastic transformation by ⁶⁰Co -rays is likely due to the lack of a G2/M arrest observed at low doses resulting in higher transformation frequencies per dose, whereas the lower frequencies per dose observed for higher doses are likely related to the induction of a G2/M arrest.

Response to Letter to the Editor

Bithell, J. F., Keegan, T. J., Kroll, M. E., Murphy, M. F. G., Vincent, T. J. — Wed, 07 Oct 2009 03:41:54 PDT

RADIATION EXPOSURE FOR MEDICAL STAFF PERFORMING QUANTITATIVE CORONARY PERFUSION PET WITH 13N-AMMONIA

Kristoffersen, U. S., Gutte, H., Skovgaard, D., Andersen, P. A., Kjaer, A. — Sat, 03 Oct 2009 01:14:08 PDT

Purpose: To evaluate radiation doses to medical staff performing quantitative ¹³N-ammonia myocardial perfusion positron emission tomography (PET). Methods: Seventeen PET examinations were performed. Nine examinations consisted of two PET scans (one during rest and one after pharmacological stress with dipyridamole) and eight examinations consisted of three PET scans (additionally a scan after cold pressor testing). The two nuclear technologists and the physician attending the examinations were equipped with an electronic dosemeter over the chest and thermoluminescent dosimetry chips on the right index finger and wrist. Results: The highest mean equivalent dose per examination for a staff member was 453 µSv (417–490 µSv) to the right index finger, 138 µSv (127–149 µSv) to the right wrist and 13 ± 0.8 µSv to the chest. Conclusions: Myocardial perfusion PET with ¹³N-ammonia exposes the staff to radiation doses that are comparable to doses from ¹⁸F-fluoro-deoxy-glucose scans and the annual doses are well within the recommended upper limits for radiation workers.

THE IMPACT OF AUTOMATIC WEDGE FILTER ON PHOTONEUTRON AND PHOTON SPECTRA OF AN 18-MV PHOTON BEAM

Ghavami, S.-M., Mesbahi, A., Mohammadi, E. — Tue, 29 Sep 2009 05:57:27 PDT

The effect of an automatic wedge filter on photon and photoneutron spectra of a medical linac was evaluated using the Monte Carlo method. The head of an Elekta SL75/25 was simulated using the MCNPX Monte Carlo code. The photon and photoneutron spectra for open and wedged beams were calculated at the isocentre with a source to axis distance of 100 cm. For a wedged beam, the neutron fluence was from 3.84 to 7.2 times higher for field sizes from 10 x 10 to 30 x 30 cm². The neutron fluence is decreased with field size for open beams and is increased with field size for wedged beams The photon beam spectra became harder and the mean energy was 6 % higher for a wedged beam, which led to a 4 % increase in relative depth dose and a better skin sparing effect. The results here recommend that the higher photoneutron fluence of the wedged beam should be taken into account in patient dosimetry and shielding calculations.

DEVELOPMENT OF IMPROVED FREE-AIR IONISATION CHAMBER AS ABSOLUTE DOSIMETRY STANDARD FOR LOW-ENERGY X RAYS IN INER

Chu, C.-H., Kuan, W.-P., Kurosawa, T., Lin, U.-T., Chen, I.-J., Chen, W.-L. — Tue, 29 Sep 2009 05:57:25 PDT

The National Radiation Standard Laboratory of the Institute of Nuclear Energy Research (INER) designed and constructed an improved Attix style free-air ionisation chamber (FAC) for low-energy X-ray measurements. Clinically, X rays in this energy range are used in mammography radiology. This chamber is also used to perform air-kerma measurements. The original Attix two-sectional design was redesigned by INER using the piston design. The correction factors were determined experimentally for volume estimation, ion recombination and air attenuation. The aperture transmission, wall transmission, electron loss and photon scatter correction factors were determined using Monte Carlo calculations. INER established the Bureau International des Poids et Mesures (BIPM) X-ray beam code and performed a comparison of secondary standard air-kerma calibration factors for 10–50 kV low- energy X rays to verify the experimental accuracy and measurement consistency of the improved chamber. The INER–NMIJ/National Institute of Advanced Industrial Science and Technology (AIST) experimental results comparison using a transfer chamber yielded a difference <1.0% at the 95% confidence level in calibration factors. The overall uncertainty for the X-ray measurement in terms of air kerma was <0.6% at the 95% confidence level. These results indicated that the improved FAC is capable of serving as a primary standard as well as a trace standard in low-energy X-ray calibration services in Taiwan and even forming a basis for the future mammography X-ray air-kerma primary standard.

PROBABILITY MAPPING OF INDOOR RADON-PRONE AREAS USING DISJUNCTIVE KRIGING

Raspa, G., Salvi, F., Torri, G. — Tue, 29 Sep 2009 05:57:23 PDT

After a reference to the use of maps of radon-prone areas for indoor radon risk management, and to the methods used to produce them, there is a brief illustration of the geostatistical method of disjunctive kriging (DK) introduced by G. Matheron as a substitute for conditional expectation. There are some good reasons of using this method for the mapping of radon-prone areas as follows: (1) spatial correlation is exploited; (2) unbiasedness is conserved even in the conditions of quasi-stationarity; (3) lognormality of the data is not required; (4) choosing the point estimation allows drawing up smooth probability maps. An application of DK is also presented for the production of probability maps in a campaign of indoor radon measurements conducted by Institute for Environmental Protection and Research, in the provinces of Rome and Viterbo (Central Italy). In the application, it is assessed in particular how much the spatial correlation, even though low, influences the results.

AUTOMATED EFFECTIVE DOSE ESTIMATION IN CT

Fri, 25 Sep 2009 01:19:35 PDT

European regulations require the dose delivered to patients in CT examinations to be monitored and checked against reference levels. Dose estimation has traditionally been performed manually. This is time consuming and therefore it is typically performed on just a few patients and the results extrapolated to the general case. In this work an automated method to estimate the dose in CT studies is presented. The presented software downloads CT studies from the corporative picture archiving and communication system and uses the information on the DICOM headers to perform the dose calculation. Automation enables dose estimations to be performed on a larger fraction of studies, enabling more significant comparisons with diagnostic reference levels (DRLs). A preliminary analysis involving 5800 studies is presented with details of dose distributions for selected CT protocols in use at a university hospital. Average doses are compared with DRLs. Effective dose estimations are also compared with estimations based on the dose length product.

AN INVESTIGATION ON RADON AND THORON RESPONSE OF ALPHA-TRACK DETECTORS USED IN THE WINNIPEG CASE-CONTROL STUDY

Chen, J., Walker, B., Sorimachi, A., Takahashi, H., Tokonami, S. — Wed, 23 Sep 2009 23:13:00 PDT

The alpha-track detector was well designed for long-term radon measurements in the 1992 Winnipeg case–control study. However, its diffusion characteristic for thoron in comparison to radon was yet unknown. An investigation on radon and thoron response of these detectors was undertaken. The results showed that the relative sensitivity between thoron and radon is 2 %, i.e. the detector sensitivity to radon is about 50 times higher than the sensitivity to thoron. It can be concluded that there was no significant influence of thoron on the radon measurements with these detectors.

RADIO-TOXICITY OF SPENT FUEL OF THE ADVANCED HEAVY WATER REACTOR

Anand, S., Singh, K. D. S., Sharma, V. K. — Wed, 23 Sep 2009 09:10:03 PDT

The Advanced Heavy Water Reactor (AHWR) is a new power reactor concept being developed at Bhabha Atomic Research Centre, Mumbai. The reactor retains many desirable features of the existing Pressurised Heavy Water Reactor (PHWR), while incorporating new, advanced safety features. The reactor aims to utilise the vast thorium resources available in India. The reactor core will use plutonium as the make-up fuel, while breeding ²³³U in situ. On account of this unique combination of fuel materials, the operational characteristics of the fuel as determined by its radioactivity, decay heat and radio-toxicity are being viewed with great interest. Radio-toxicity of the spent fuel is a measure of potential radiological hazard to the members of the public and also important from the ecological point of view. The radio-toxicity of the AHWR fuel is extremely high to start with, being ~10⁴ times that of the fresh natural U fuel used in a PHWR, and continues to remain relatively high during operation and subsequent cooling. A unique feature of this fuel is the peak observed in its radio-toxicity at ~10⁵ y of decay cooling. The delayed increase in fuel toxicity has been traced primarily to a build-up of ²²⁹Th, ²³⁰Th and ²²⁶Ra. This phenomenon has been observed earlier for thorium-based fuels and is confirmed for the AHWR fuel. This paper presents radio-toxicity data for AHWR spent fuel up to a period of 10⁶ y and the results are compared with the radio-toxicity of PHWR.

RADON CONCENTRATIONS IN THREE UNDERGROUND LIGNITE MINES IN TURKEY

Cile, S., Altinsoy, N., Celebi, N. — Mon, 21 Sep 2009 06:05:15 PDT

Monitoring of radon in underground mines is important in order to assess the radiological hazards to occupational workers. Radon concentration levels in three underground lignite mines (Tunçbilek, Ömerler and Eynez) of Turkey were obtained in this study. For this reason, atmospheric radon level measurements were carried out in mines using CR-39 track detectors. Chemical etching of the detector tracks and subsequent counting were performed at Çekmece Nuclear Research and Training Center. The obtained results were evaluated according to the International Commission of Radiation Protection and the Turkish Atomic Energy Authority whose radon action levels for workplaces are 500–1500 and 1000 Bq^–3, respectively. The radon gas concentrations in the lignite mines were determined to be between 50 ± 7 and 587 ± 16 Bq m^–3. The results obtained in these experiments are far under the action levels. The computed radon doses for the mine workers of Tunçbilek, Ömerler and Eynez lignite mines are 1.23, 2.44 and 1.47 mSv y^–1, respectively.

LUNG DOSIMETRY FOR INHALED RADON PROGENY IN SMOKERS

Baias, P. F., Hofmann, W., Winkler-Heil, R., Cosma, C., Duliu, O. G. — Fri, 18 Sep 2009 21:36:26 PDT

Cigarette smoking may change the morphological and physiological parameters of the lung. Thus the primary objective of the present study was to investigate to what extent these smoke-induced changes can modify deposition, clearance and resulting doses of inhaled radon progeny relative to healthy non-smokers (NSs). Doses to sensitive bronchial target cells were computed for four categories of smokers: (1) Light, short-term (LST) smokers, (2) light, long-term (LLT) smokers, (3) heavy, short-term (HST) smokers and (4) heavy, long-term (HLT) smokers. Because of only small changes of morphological and physiological parameters, doses for the LST smokers hardly differed from those for NSs. For LLT and HST smokers, even a protective effect could be observed, caused by a thicker mucus layer and increased mucus velocities. Only in the case of HLT smokers were doses higher by about a factor of 2 than those for NSs, caused primarily by impaired mucociliary clearance, higher breathing frequency, reduced lung volume and airway obstructions. These higher doses suggest that the contribution of inhaled radon progeny to the risk of lung cancer in smokers may be higher than currently assumed on the basis of NS doses.

SPECIFIC ABSORBED FRACTIONS FOR INTERNAL ELECTRON EMITTERS DERIVED FOR A SET OF ANATOMICALLY REALISTIC REFERENCE PREGNANT FEMALE MODELS

Guo, B., Xu, X. G., Shi, C. — Fri, 18 Sep 2009 21:36:26 PDT

The specific absorbed fraction (), defined by the Medical Internal Radiation Dose Committee, is generally applied to evaluate the average absorbed dose in a target organ as a result of radioactive materials deposited in a source organ. This paper reports a new set of values for internal electron emitters ranging from 10 keV to 4 MeV from various internal organs of the mother to the fetus based on three newly developed pregnant female tomographic models, called RPI-P3, RPI-P6 and RPI-P9. The results show a linear log relationship between values and electron energy. The linear log coefficients have been derived and reported. The relationship between values and mean distances between source organs and the fetus were also determined to allow for individual dosimetry. Since the RPI-P models have finer details of human anatomy and more realistic organ volumes and geometries, which follow the latest ICRP reference values, the newly derived values could be used as reference values in determination of the dose to the fetus from internal electron emitters.

PUBLIC EXPOSURE TO HAZARDS ASSOCIATED WITH NATURAL RADIOACTIVITY IN OPEN-PIT MINING IN GHANA

Fri, 18 Sep 2009 22:00:10 PDT

The results of studies carried out on public exposure contribution from naturally occurring radioactive materials (NORMS) in two open-pit mines in the Western and Ashanti regions of Ghana are reported. The studies were carried out under International Atomic Energy Agency-supported Technical Co-operation Project GHA/9/005. Measurements were made on samples of water, soil, ore, mine tailings and air using gamma spectrometry. Solid-state nuclear track detectors were used for radon concentration measurements. Survey was also carried out to determine the ambient gamma dose rate in the vicinity of the mines and surrounding areas. The effective doses due to external gamma irradiation, ingestion of water and inhalation of radon and ore dusts were calculated for the two mines. The average annual effective dose was found to be 0.30 ± 0.06 mSv. The result was found to be within the levels published by other countries. The study provides a useful information and data for establishing a comprehensive framework to investigate other mines and develop guidelines for monitoring and control of NORMS in the mining industry and the environment as a whole in Ghana.

A STUDY OF BACKGROUND RADIOACTIVITY LEVEL FOR TEKIRDAG, TURKEY

Kam, E., Yarar, Y., Bozkurt, A. — Fri, 18 Sep 2009 21:36:25 PDT

The level of background radiation for Tekirdag province of north-western Turkey was assessed in this study. Radon concentrations in indoor air were determined using CR-39 nuclear track detectors and the average ²²²Rn activity was found to be 86 Bq m^–3 (equivalent to an annual effective dose of 2.2 mSv). Measurements of gamma doses in air were performed using plastic scintillators and the average absorbed gamma dose rates for indoor and outdoor were found to be 5.7 and 5 µR h^–1, respectively, corresponding to an annual effective dose of 300 µSv. The radionuclide activity concentrations in soil samples collected from the study area were measured through gamma-ray spectrometry and the average activities were determined as 29, 39 and 580 Bq kg^–1 for the natural radionuclides ²³⁸U, ²³²Th and ⁴⁰K, respectively, and 5.2 Bq kg^–1 for the fission product ¹³⁷Cs. The natural radioactivity sources resulted in an annual effective dose of 75 µSv. The radioactivity levels of drinking water samples were measured as 0.044 and 0.1 Bq l^–1 for gross alpha and gross beta activities using a low-background counting technique (equivalent to an annual effective dose of 9 µSv). The results of this study showed that the region's background radioactivity level is in agreement with most Turkish cities.