Dose to the interventional radiologist in CTF-guided procedures.

The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the body including the hands and fingers; to suggest recommendations for individual monitoring; and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, Hp(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, Hp(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess Hp(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36-39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; Hp(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information.

EURADOS education and training activities.

This paper provides a summary of the Education and Training (E&T) activities that have been developed and organised by the European Radiation Dosimetry Group (EURADOS) in recent years and in the case of Training Courses over the last decade. These E&T actions include short duration Training Courses on well-established topics organised within the activity of EURADOS Working Groups (WGs), or one-day events integrated in the EURADOS Annual Meeting (workshops, winter schools, the intercomparison participants' sessions and the learning network, among others). Moreover, EURADOS has recently established a Young Scientist Grant and a Young Scientist Award. The Grant supports young scientists by encouraging them to perform research projects at other laboratories of the EURADOS network. The Award is given in recognition of excellent work developed within the WGs' work programme. Additionally, EURADOS supports the dissemination of knowledge in radiation dosimetry by promoting and endorsing conferences such as the individual monitoring (IM) series, the neutron and ion dosimetry symposia (NEUDOS) and contributions to E&T sessions at specific events.

APOA5 polymorphisms associated with lipid metabolism in Brazilian children and adolescents.

Single nucleotide polymorphisms in the APOA5 gene have been studied for their association with metabolic syndrome. Thus, elucidating the effect of the mechanism involved in APOA5 gene polymorphisms on lipid metabolism is of great importance. In this study we aimed to determine the allelic and genotypic frequencies of -1131T>C, Ser19Trp, and intergenic APOA4/A5 and to evaluate the association between these variants with plasma lipid levels in children and adolescents from Brazil. This study included 524 healthy children and adolescents from Mother and Child Hospital in Recife, Pernambuco, Brazil. Data were obtained on medical history, drug intake, lifestyle variables, and demography. DNA from collected samples was extracted and genotyped for the three polymorphisms. In this studied population, triglycerides and very low-density protein levels were significantly high in subjects carrying the 19WW genotype (P < 0.001), demonstrating the presence of this genetic risk factor in children and adolescents.

EURADOS ISO/IEC 17025 guidance for IMS: suggestions on how to interpret and implement the requirements including examples from accredited laboratories.

Individual monitoring of external radiation is an activity usually regulated by national regulatory bodies in most countries. Regulations generally contain technical requirements to be met by the individual monitoring services (IMS), in order to ensure that the measurements are correct and therefore the dosimetry results are reliable. In some countries, the requirements include or even consist of the accreditation of the service according to the standard ISO/IEC 17025: 'General requirements for the competence of testing and calibration laboratories.' It is a fact that accreditation is a growing trend among European IMS as a way to guarantee confidence in their technical competence. The acceptance of the dosimetry results between countries and their indentation in the respective National Dose Registries is facilitated if laboratories conform to the ISO/IEC 17025 standard. In the framework of the activities of EURADOS (European Radiation Dosimetry Group) working group 2 'Harmonization of Individual Monitoring in Europe' and attending to the concern of many European IMS in the process of accreditation, a guide has been prepared. The purpose was to assist and encourage IMS to apply for accreditation and to share the authors' own experience with the process. The guide intends to be a practical reference for IMS on how to interpret and implement the ISO/IEC 17025 requirements to the specific activity of a personal dosimetry service for external radiation, emphasizing those aspects of special interest. It includes examples from dosimetry laboratories already accredited. The major novelties from a new edition of ISO/IEC 17025: 2017 are also identified in the guide. Finally, the guide aims to assist the auditing process, giving examples of auditor's questions and how to show evidence of compliance. The main findings are presented.

Study on the dose profile in CT-fluoroscopy.

This work aims to contribute to the description of the dose profile in Computed Tomography Fluoroscopy (CTF). Our approach uses a function model to fit the single slice dose profiles (SSDP) for any point inside the gantry of the CT unit, with special attention to points off the rotation axis. The function model was successfully tested with measurements performed using GafChromic film. The parameters of the SSDP at the rotation axis (isocenter) and at 8 cm and 16 cm off the isocenter were determined. The model allows an estimation of the slice thickness at the isocenter and for points at 8 cm and 16 cm off the isocenter. The differences between the slice thicknesses results in overestimation of the Computed Tomography Dose Index, CTDI, by values as high as 20% if the nominal slice thickness instead of the model estimated value is used. The results obtained in this work provided a good description of the dose profiles, which can be used in further studies such as comparisons with measurements performed with phantoms and patients.

Protective Barriers and Radiant Exposure Delivered from Light-curing Units.

OBJECTIVE: To evaluate the influence of different protective barriers as a function of the photoactivation distances on the radiant exposure of several light-curing units (LCU). The influence of the protective barriers on the degree of conversion of an adhesive resin was also evaluated. METHODS: Five LCUs were evaluated: Valo Cordless-used in standard mode (Ultradent, South Jordan, USA); Radii-cal-used in continuous mode (SDI, Bayswater, AU); Emitter D-used in continuous mode (Schuster, Santa Maria, BR); Bluephase N-used in high-intensity mode (Ivoclar Vivadent, Schaan, LI); and Rainbow Curing Light-used in continuous mode (Axdent, Guangdong, CN). For each LCU, radiant exposure was measured with a spectrometer (MARC Resin Calibrator) using three different protective barriers (low-density polyethylene, polyvinyl chloride, or Radii-cal barrier sleeves) and five photoactivation distances (0, 2, 5, 10, and 20 mm). The degree of conversion of an adhesive resin (Adper Scotchbond Multi-Purpose, 3M ESPE, St. Paul, USA) was measured through Fourier-transform infrared spectroscopy. The translucency parameter of protective barriers was measured with a spectrophotometer. For all statistical tests, a significance level of α = 0.05 was set. RESULTS: For all LCUs tested, radiant exposure was found to be significantly influenced by both protective barriers and curing distance (p≤0.001). In general terms, all the protective barriers significantly decreased the radiant exposure. Radii-cal barrier sleeves were the protective barrier that most decreased the radiant exposure. Irrespective of the protective barrier used, none of the LCU equipment reached the required minimum radiant exposure of 16 J/cm2 at 10 mm of curing distance. The degree of conversion was not effected by either LCU or a protective barrier (p≥0.211). CONCLUSIONS: Protective barriers and photoactivation distance reduced the radiant exposure emitted by different LCUs.

TYPE TESTING OF LiF:Mg,Cu,P (TLD-100H) WHOLE-BODY DOSEMETERS FOR THE ASSESSMENT OF Hp(10) AND Hp(0.07).

In this work, the initial results of the type testing of the LiF:Mg,Cu,P (TLD-100H) whole-body personal dosemeters are presented. An assessment of reproducibility, linearity of the response, the residual signal as a function of the dose, energy and angular dependence of the response was performed. In general, the dosemeters show good reproducibility for different dose values and a linear behaviour for a range between 0.1 and 300 mSv. The detection limits obtained are lower than 50 µSv. The system presents a good energy and angular response for different radiation qualities.

Examining life-course influences on chronic disease: the importance of birth cohort studies from low- and middle- income countries. An overview.

The objectives of this overview are to describe the past and potential contributions of birth cohorts to understanding chronic disease aetiology; advance a justification for the maintenance of birth cohorts from low- and middle-income countries (LMIC); provide an audit of birth cohorts from LMIC; and, finally, offer possible future directions for this sphere of research. While the contribution of birth cohorts from affluent societies to understanding disease aetiology has been considerable, we describe several reasons to anticipate why the results from such studies might not be directly applied to LMIC. More than any other developing country, Brazil has a tradition of establishing, maintaining and exploiting birth cohort studies. The clear need for a broader geographical representation may be precipitated by a greater collaboration worldwide in the sharing of ideas, fieldwork experience, and cross-country cohort data comparisons in order to carry out the best science in the most efficient manner. This requires the involvement of a central overseeing body--such as the World Health Organization--that has the respect of all countries and the capacity to develop strategic plans for 'global' life-course epidemiology while addressing such issues as data-sharing. For rapid progress to be made, however, there must be minimal bureaucratic entanglements.

Radioactivity in the environment around past radium and uranium mining sites of Portugal.

Measurements of ambient radiation doses and determination of radionuclide concentrations in mining waste and soils were performed in 60 areas of former radium and uranium mining. In several places, mining waste and low-grade uranium ore left on the surface contain radioactivity above regional background. Most of the former mining sites present no enhanced radionuclide concentrations. However, in the mining facilities where the radioactive ore was chemically extracted, mill tailings contain materials with elevated levels of radioactivity, up to 200 times the levels in unaffected soils of the region. Mud from neutralization ponds used to treat acid mine waters contains also elevated radionuclide concentrations. Furthermore, depending on the type of waste, the radioelement composition varies. Environmental rehabilitation measures shall take these differences into account in order to prevent in the long term the radioactive contamination of agriculture soils and water resources, and to ensure adequate radiological protection to the public and to the environment.

In-flight dose estimates for aircraft crew and pregnant female crew members in military transport missions.

Aircraft fighter pilots may experience risks other than the exposure to cosmic radiation due to the characteristics of a typical fighter flight. The combined risks for fighter pilots due to the G-forces, hypobaric hypoxia, cosmic radiation exposure, etc. have determined that pregnant female pilots should remain on ground. However, several military transport missions can be considered an ordinary civil aircraft flight and the question arises whether a pregnant female crew member could still be part of the aircraft crew. The cosmic radiation dose received was estimated for transport missions carried out on the Hercules C-130 type of aircraft by a single air squad in 1 month. The flights departed from Lisboa to areas such as: the Azores, several countries in central and southern Africa, the eastern coast of the USA and the Balkans, and an estimate of the cosmic radiation dose received on each flight was carried out. A monthly average cosmic radiation dose to the aircraft crew was determined and the dose values obtained were discussed in relation to the limits established by the European Union Council Directive 96/29/Euratom. The cosmic radiation dose estimates were performed using the EPCARD v3.2 and the CARI-6 computing codes. EPCARD v3.2 was kindly made available by GSF-National Research Centre for Environment and Health, Institute of Radiation Protection (Neuherberg, Germany). CARI-6 (version July 7, 2004) was downloaded from the web site of the Civil Aerospace Medical Institute, Federal Aviation Administration (USA). In this study an estimate of the cosmic radiation dose received by military aircraft crew on typical transport missions is made.

Occupational exposure in nuclear medicine in Portugal in the 1999-2003 period.

The annual doses received by the staff of nuclear medicine departments from public hospitals and private clinics and evaluated by the Individual Monitoring Service of the Radiological Protection and Nuclear Safety Department (DPRSN) of the Nuclear and Technological Institute (ITN) in Portugal, in the 5 y period from 1999 to 2003, are analysed and presented in this paper. In the 1999-2003 period, ITN-DPRSN monitored on an average 462 workers from nuclear medicine departments, which represents 6% of the 8000 workers of the medical field (approximately). The medical sector represents 80-85% of all the monitored population in Portugal. The professions of the monitored workers at nuclear medicine departments were identified by the respective departments as administrative, auxiliary, medical doctor, nuclear medicine technician, nurse, pharmacist and physicist. This information was collected at the onset of the monitoring and was updated over the last 3 y. The annual whole-body doses evaluated in the period 1999-2003 were used to derive the distribution of workers by dose intervals for every profession. The respective annual average doses and annual collective doses, as well as, the total average and total collective doses for the nuclear medicine sector were also determined and are presented. Internal radiation hasn't been monitored.

Factors associated with sickle cell disease mortality among hospitalized Angolan children and adolescents.

BACKGROUND: Sickle cell disease complications are an important mortality cause in children mainly in Africa and India. Notwithstanding the magnitude of the problem on the African continent, studies identifying factors related to the adverse outcomes of sickle cell disease in the pediatric population are still scarce. OBJECTIVE: To identify prognostic factors associated with mortality in children and adolescent aged under fifteen years with diagnosis of sickle cell disease. METHODS: Patients meeting inclusion criteria were listed and randomly selected. Clinical and laboratory data collected at time of admission were collected from medical records through the use of standard forms. The association between mortality and explanatory variables was tested using univariable and multivariable analysis. RESULTS: The overall mortality rate was 64 (12.9%), and bacterial infections 26 (40.1%) were the most common cause of death. Place of residence out of Luanda, lack of outpatient follow-up, symptoms onset more than three days, disease manifestation before age of eighth months and hemoglobin level of < 7 g/dl were independent risk factors related to death. In the study population, sickle cell related deaths were related to quality of health care and access to care. CONCLUSION: The creation of regional sickle cell disease centers to support those afflicted by the disorder and their families would contribute to reduce the burden associated with the disease.

Implications of the high voltage induced variation on TL readings.

The high voltage (HV) induced variation on the thermoluminescence (TL) and on the reference light (RL) intensity was investigated in a previous work, which also allowed for the definition of warning levels for all the parameters of the readers' start up test. Based on the results obtained, a modification of the start up procedure was suggested: 'a 10 min warm up time was allowed prior to the beginning of the reader's start up tests. The actual and previous HV values should differ less than +/-5 V. In case it exceeds, a second test should be performed. If the difference exceeds +/-10 V, the voltage should be manually adjusted to the previous value and a calibration of the reader is needed. Should this occur for more than two successive days, maintenance should be called'. The results of the readers' start up tests obtained since the implementation of the start up procedure are analysed and the warning levels considered are discussed. Charts of the HV-induced variation on the TL and RL readings were obtained, compared with the preliminary results and the implications on the start up procedure are discussed.

Long-term stability of a TLD-based individual monitoring system.

The thermoluminescence dosemeter (TLD) system at the Individual Monitoring Service (IMS) of the Nuclear Technology Institute (ITN) at the Radiological Protection and Nuclear Safety Department (DPRSN) comprises two 6600 Harshaw readers and the Harshaw 8814 TL card and the holder containing two LiF:Mg,Ti (TLD-100) dosemeters for the evaluation of H(p)(10) and H(p)(0.07). The readers are calibrated on a monthly basis and as part of the quality assurance programme implemented at the IMS a set of dosemeters is issued monthly to the DPRSN's Standard Dosimetry Laboratory for linearity measurements. The results obtained since November 2001 are presented. Fading and sensitivity change experiments are carried out every month covering 8 week periods so that enough time is given to simulate issuing, integrating and receiving times and respective delays. A set of 96 dosemeters organised in eight subsets of 12 are used. In each subset, four dosemeters are irradiated and stored at room temperature (RT), four are not irradiated at all and the last four are irradiated after storage. The 12 dosemeters of each subset are readout at the same time, one per week, covering the 8 week period. The results from the sets irradiated and stored at different periods allowed for the evaluation of fading and sensitivity changes experienced over the whole monitoring period and respective preparation time and readout delays. Time evolution charts of the reader calibration factors, of the linearity parameters and of the evolution of the integrated area in the region of dosimetric interest with storage at RT were obtained. This paper aims to quantify the long-term stability of the TLD system in use at the IMS.

CHARACTERIZATION OF AN ACTIVE DOSEMETER ACCORDING TO IEC 61526:2010.

The active personal dosemeter, RaySafe i2, allows the measurement and record of Hp(10) in real time, every second, via wireless technology for real-time display on a portable computer and/or a local network. The system seems particularly attractive for individual monitoring at clinical facilities where high intensity and varying radiation fields may occur, as it enables the user to acknowledge and optimize the dose and dose rate values in real time for each procedure. Prior to its use, the system was characterized at the Metrology Laboratory of Ionizing Radiation of IST-LPSR aiming at the metrological characterization of the system in accordance with IEC 61526:2010 for metrological control purposes and to verify the technical specifications stated by the manufacturer.

Assessment of the mean glandular dose using LiF:Mg,Ti, LiF:Mg,Cu,P, Li2B4O7:Mn and Li2B4O7:Cu TL detectors in mammography radiation fields.

The aim of this paper is the characterization of four thermoluminescence detectors (TLD), namely, LiF:Mg,Ti, LiF:Mg,Cu,P, Li2B4O7:Mn and Li2B4O7:Cu for the measurement of the entrance surface air kerma (ESAK) and estimation of the mean glandular dose (MGD) in digital mammography examinations at hospitals and clinics. Low-energy x-ray beams in the typical energy ranges of mammography, produced with a tungsten target and additional 60 µm molybdenum filtration were implemented and characterized at the Laboratory of Metrology of Ionizing Radiation at Instituto Superior Técnico. These beams were used for the characterization of the TLDs in terms of sensitivity, linearity, reproducibility, energy dependence and fading at 40 °C. The energy dependence test was further extended using clinical beams produced by mammography units at hospitals and clinics. The method proposed by the International Atomic Energy Agency was used for the measurement of ESAK and assessment of MGD. The combined standard uncertainty for the measurement of ESAK (and MGD) was determined in accordance to the Guide to the expression of uncertainty in measurement. The x-ray beams generated in the 23-40 kVp range presented HVL values from 0.36 to 0.46 mm Al. The beam produced at 28 kVp (HVL 0.39 mm Al) was considered as reference. The radiation field defined a circle with 84 mm diameter with a maximum variation of the beam intensity of less than 1% at the top flat (plateau) within 4 cm of the central axis. The estimated total uncertainty for the measurement of air kerma was 0.42%. All the TL detectors tested showed good performance except the commercial Li2B4O7:Mn (or TLD-800) which was excluded due to its poor sensitivity in our experimental set up. Both lithium fluorides showed better linearity and reproducibility as well as lower energy dependence and fading when compared to lithium borates. The stable behaviour of LiF:Mg,Ti and LiF:Mg,Cu,P detectors is reflected in the low combined standard uncertainty of ±5.6% and ±4.3% respectively (or ±5.1% and ±3.6% if fading is neglected). In general a total combined uncertainty lower than ±10% for the measurement of ESAK was obtained for the four TL materials studied.

FADING EFFECT OF LiF:Mg,Ti AND LiF:Mg,Cu,P Ext-Rad AND WHOLE-BODY DETECTORS.

Thermoluminescence dosemeters are widely used in individual and environmental monitoring. The aim of this work was to compare the thermal stability of dosemeters of the Ext-Rad and whole-body card types with LiF:Mg,Ti and LiF:Mg,Cu,P detectors stored at different temperatures and periods. The dosemeters were stored at 0°C, room temperature and 40°C for periods that lasted 8, 30, 45, 90 and 120 d. In general, TLD-100H detectors present higher TL signal stability than TLD-100 detectors. The intensity of the signal remained constant for both materials for storage periods at 0°C. At RT the same results was observed for TLD-100H. For TLD-100 detectors, a maximum variation of 22 % was registered for the longest period. At 40°C the TL signal decreased with storage time for both detectors. The TL signal of TLD-100H detectors presented maximum variations of 12 % whereas for TLD-100 detectors, larger variations of 25 % were observed.

ENVIRONMENTAL MONITORING WITH PASSIVE DETECTORS AT CTN IN PORTUGAL.

The aim of this work is to present the methods in use for environmental dose assessment with passive detectors at Campus Tecnológico e Nuclear (CTN) of Instituto Superior Técnico, in Portugal. The methods are based on LiF:Mg,Ti (TLD-100) detectors inserted in Harshaw holders placed at four locations and exchanged on a quarterly basis. An initial group of measurements allowed the estimation of the time interval necessary to attain a stable value, the determination of a fading factor, as well as the calculation method for the assessment of the ambient dose equivalent rate.

APOA1/C3/A4 gene cluster variability and lipid levels in Brazilian children.

Genetic studies have suggested that polymorphisms of genes coding for apolipoproteins are significant determinants of serum lipoprotein and lipid levels in adults. However, only a few studies have investigated the association of these polymorphisms in children. Therefore, in the present investigation we studied the distribution of APOA1 -75 G>A, +83 C>T, APOC3 -482 C>T, -455 T>C and 3238 C>G, and APOA4 Q360H and T347S polymorphisms and their influence on plasma lipoprotein levels in children from a Brazilian northeastern admixed population. The seven polymorphic sites were genotyped in 414 children aged 5 to 15 years (mean 8.9 +/- 2.9). The genotypes of the seven polymorphic sites were assessed by PCR-RFLP methods. The frequencies of the less common alleles were, in general, intermediate among parental populations, as expected. Strong linkage disequilibrium was detected between polymorphisms at the APOA1, APOC3 and APOA4 loci in this admixed population sample. Overall the genotype effects seen in adults were weaker or absent in children. The APOC3/-455 and APOA4 T347S variants showed significant effects on HDL cholesterol in girls (P = 0.033 and P = 0.016, respectively). Significantly higher plasma total (P = 0.003) and LDL cholesterol (P = 0.004) levels were observed in boys who were carriers of the 3238G allele at the APOC3/3238 C>G site. These results disclosed an overall absence of associations between these polymorphisms and lipids in children. This finding is not unexpected because expression of the effect of these polymorphisms might depend on the interaction with environmental variables both internal and external to the individual.

Fetal influences on neonatal blood pressure.

OBJECTIVE: To identify if there is a relationship between some newborn variables (baby's sex, Apgar score, postnatal age, birth weight, birth length, and head circumference) and blood pressure (BP) in healthy term newborns. STUDY DESIGN: A cross-sectional hospital-based study was carried out to determine BP levels and a cutoff point for hypertension in healthy term newborns. Afterward, a comparative study was conducted to identify fetal factors that could influence BP in this specific group. RESULTS: According to the cutoff point (95th percentile), 34 infants were considered to be hypertensive. During the univariate analyses, infants with higher BP were heavier, longer, and had larger head circumference. After the multivariate analyses, birth weight was the only variable associated with higher BP in babies. Other newborn variables analyzed (baby's sex, Apgar score, and postnatal age) showed no influence on the babies' BP. CONCLUSION: There is a positive relationship between birth weight and BP in healthy term newborns.