Factors impacting public acceptance of medical radiation exposure

International Nuclear Information System (INIS)

Tsuji, Satsuki; Kanda, Reiko

2009-01-01

We undertook a survey to determine the public acceptance of medical radiation exposure throughout Japan, and 1,357 responses (67.9% response rate) were obtained using a two-stage systematic stratified random sampling method. The acceptance of exposure of children was generally similar to that of adults. For each of the attributes, 45-60% of the participants were accepting of exposure for cancer treatment and diagnosis, but only 30% were accepting of exposure for X-ray diagnoses of bone fractures and dental caries. In general, the presence of a child did not markedly affect women's acceptance of exposure. Factor analyses identified 3 factors influencing the acceptance of child exposure: symptomatic diseases to determine treatment, the possibility of high-risk diseases (or major organ diseases), and the association with cancer. Cluster analysis showed 4 clusters: a positive group regarding children's exposure for the diagnosis of bone fractures and dental caries (12.9% of all participants), a positive group for major organ disease and cancer (15.5%), a negative group excluding cancer (55.2%), and a positive group for all cases (16.4%). The cluster distributions revealed that mothers with 10- to 18-year-old firstborn children showed a tendency to accept the medical radiation exposure of their children in all cases. (author)

Radiation exposure in X-ray examinations of the pelvis

International Nuclear Information System (INIS)

Kainberger, F.

1977-01-01

The article reports on radiation exposure during X-ray treatment of the pelvis of children. Special attention is paid to genetical radiation exposure. Generally a dose of 100 mR is assumed to be taken up if no adequate shielding is provided. In order to be able to judge the value of a shielding with suitable lead-equivalent values, measurements were carried out on a phantom. These measurements showed that the dosage can be reduced by at least a factor 100 by using a lead shielding. When doing this, the lead equivalent value must be 1 mm. The form of gonad protection also has great importance for the shielding efficiency. (orig.) [de

Calculating gamma dose factors for hot particle exposures

International Nuclear Information System (INIS)

Murphy, P.

1990-01-01

For hot particle exposures to the skin, the beta component of radiation delivers the majority of the dose. However, in order to fully demonstrate regulatory compliance, licenses must ordinarily provide reasonable bases for assuming that both the gamma component of the skin dose and the whole body doses are negligible. While beta dose factors are commonly available in the literature, gamma dose factors are not. This paper describes in detail a method by which gamma skin dose factors may be calculated using the Specific Gamma-ray Constant, even if the particle is not located directly on the skin. Two common hot particle exposure geometries are considered: first, a single square centimeter of skin lying at density thickness of 7 mg/cm 2 and then at 1000 mg/cm 2 . A table provides example gamma dose factors for a number of isotopes encountered at power reactors

Annama H chondrite-Mineralogy, physical properties, cosmic ray exposure, and parent body history

Czech Academy of Sciences Publication Activity Database

Kohout, Tomáš; Haloda, J.; Halodová, P.; Meiner, M. M. M.; Maden, C.; Busemann, H.; Laubenstein, M.; Caffee, M. W.; Welten, K.C.; Hopp, J.; Trieloff, M.; Mahajan, R. R.; Naik, S.; Trigo-Rodríguez, J.M.; Moyano-Cambero, C. E.; Oshtrakh, M. I.; Maksimova, A. A.; Chukin, A. V.; Semionkin, V. A.; Karabanalov, M. S.; Felner, I.; Petrova, E. V.; Brusnitsyna, E. V.; Grokhovsky, V. I.; Yakovlev, G. A.; Gritsevich, M.; Lyytinen, E.; Moilanen, J.; Kruglikov, N. A.; Ishchenko, A. V.

2017-01-01

Roč. 52, č. 8 (2017), s. 1525-1541 ISSN 1086-9379 Institutional support: RVO:67985831 Keywords : Annama * chondrite * cosmic-ray exposure * radionuclide Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.391, year: 2016

Accidental over-exposure from dental X-ray equipment

Energy Technology Data Exchange (ETDEWEB)

Phillips, B G [National Radiological Protection Board, Harwell (UK)

1976-07-01

A description is given of an unusual dental X-ray procedure which resulted in accidental over-exposure both to the dentist and to several of his patients when a short-circuit was present in newly-installed equipment. The short-circuit by-passed the exposure control and energized the tube for certain orientations of the X-ray tube. The dentist left the patients, who wore protective aprons, to initiate the exposure themselves, using the control button. Although the warning lights were on, the dentist was not present in the room during the exposure, and the over-exposures were only detected when the developed X-ray films were found to be completely blackened. A reconstruction of the procedure enabled estimates to be made of the dose equivalents to the dentist's body and to the skin of the head, the eyes and the gonads of the patients. The dentist had overlooked several of basic principles recommended in the Code of Practice for the Protection of Persons against Ionizing Radiations from Medical and Dental Use (1972). It is pointed out that incidents involving failure of dental equipment (usually the timer mechanism) are not infrequent.

Trends in x-ray photography and patient exposure dose. Questionnaire survey results compared with those in 1973. [questionnaire survey in 1979

Energy Technology Data Exchange (ETDEWEB)

Orito, T; Sanada, S; Maekawa, R; Koshida, K; Hiraki, T [Kanazawa Univ. (Japan). School of Paramedicine

1980-04-01

The exposure doses of patients in X-ray photography are influenced by such technological factors as X-ray tube voltage, filter, sensitizing screen, film and grid. Survey by questionnnaire was made previously in 1973 on the above factors. The trends five years after were surveyed similarly, in connection with the exposure doses of patients. Questionnaires were sent to 200 radiation technicians, and 121 (60.5%) answered the survey in March, 1979. The results in the cases of simple X-ray photography and obstetric, infant and breast X-ray photographings are described. X-ray tube voltage is generally on the increase. In the sensitizing screens, exposure doses are fairly decreased due to the use of improved intensifying screen (LT-II). In the grid, the ratio 8 : 1 is used more than 5 : 1. In the usage of additional filters and in the distance of photography, improvements are desired.

Exposure Buildup Factors for Heavy Metal Oxide Glass: A Radiation Shield

DEFF Research Database (Denmark)

Manonara, S. R.; Hanagodimath, S. M.; Gerward, Leif

2011-01-01

Gamma ray exposure buildup factors for three Heavy Metal Oxide (HMO) glass systems, viz. PbO-Bi2O3-B2O3, PbO-B2O3, and Bi2O3-B2O3 glasses are presented. The computations were done by interpolation method using the Geometric Progression fitting formula and ANSI/ANS-6.4.3 library for the energy ran...... of graphs. Buildup factors of these HMO glasses cannot be found in any standard database, but they are useful for practical calculations in gamma ray shield designs, and they also, help to determine and control the thickness of the shielding material used.......Gamma ray exposure buildup factors for three Heavy Metal Oxide (HMO) glass systems, viz. PbO-Bi2O3-B2O3, PbO-B2O3, and Bi2O3-B2O3 glasses are presented. The computations were done by interpolation method using the Geometric Progression fitting formula and ANSI/ANS-6.4.3 library for the energy range...... from 0.015 to 15 MeV, up to penetration depths of 40 mfp (mean free path). The buildup factors have been studied as functions of incident photon energy and penetration depth. The variations in the buildup factor, for all the glass systems, in different energy regions; have been presented in the form...

Cosmic ray exposure in aircraft and space flight

International Nuclear Information System (INIS)

Kosako, Toshiso; Sugiura, Nobuyuki; Iimoto, Takeshi

2000-01-01

The exposure from cosmic ray radiation to the workers and public is a new aspect of exposure that was cased by the development of science and technology. ICRP Publication 60 says: 'to provide some practical guidance, the Commission recommends that there should be a requirement to include exposure to natural sources as part of occupational exposure only in the following cases: radon..., some natural radionuclides..., operation of jet air craft, space flight'. For this situation what kind of radiation protection concept is applicable? And what kind of radiation guideline and procedure are possible to propose? Here, we would like to review the past activities on this issue and to summarize the concepts in ICRP concerning to these exposure. Then the recommended radiation protection system will be proposed as one trial to this solution. In the paper the characters of cosmic ray were firstly reviewed. Cosmic rays are consisted by solar one and galactic one. Both of them have high energy and this will cause the difficulty of dosimetry because of lacking of physical and biological data. Next discussion point is a classification of exposure. For this, several classifications were done: jet airplane flight, supersonic airplane flight and space flight. Other classification is aircrew (occupational exposure), passengers (public exposure), frequent flyers (gray zone), space astronauts (special mission), and pregnant women. Considering the real level of radiation the practical radiation control is proposed including the cosmic radiation exposure prediction method by computer codes. The discussion of space astronauts is a little different for the highness of radiation doses. The dose levels will be obtained through the discussion of lifetime risk balancing their mission importance. (author)

Implementation of a primary standard for x-ray exposure

International Nuclear Information System (INIS)

Peixoto, Jose Guilherme Pereira

1991-04-01

In the scientific program of the National Laboratory for Ionizing Radiation Metrology of the Instituto de Radioprotecao e Dosimetria, which belongs to the Comissao Nacional de Energia Nuclear, a free-air ionization chamber should be established as an exposure primary standard for X-ray s of 10OKV to 250kV of potential range. Preliminary results showed that the available free-air ionization chamber was suitable to be used. The absolute measurement of the radiation quantity exposure, is performed with a free-air ionization chamber. Its geometrical volume, which allows the determination of the air mass, is defined by the effective aperture area and by the length of the region where an electrical field is applied. Most of the ions produced in such volume are collected as an ionization current. Since the collecting rod is small, and positioned far away from the X-ray beam, only a negligible fraction of ionization (0,01 %) is lost due to interactions with it. Parameters related to the measurement of the quantity exposure were evaluated, such as: air absorption, scattering inside the ionization chamber, saturation , beam homogeneity, influence Of beam size and influences of temperature, humidity and atmospheric pressure.Preliminary determination of correction factors has showed good results with 99.9% of repeatability and has demonstrated the reliability of the checked chamber as a standard instrument. (author)

Cosmic rays exposure during aircraft flight (3). Guideline and dose evaluation

International Nuclear Information System (INIS)

Yasuda, Hiroshi

2007-01-01

Radiation Council of MEXT drew up the Guideline of Cosmic Ray Exposure Control for Air Crew in 2006. The content of the Guideline and evaluation methods of dose are explained. The Guideline stated five items for Airline Company. It consists of 1) exposure dose control for air crew, 2) evaluation methods of cosmic rays exposure dose of air crew, 3) explanation and education of cosmic rays exposure for air crew, 4) reading, record and store of cosmic rays exposure dose of air crew, and 5) health control of air crew. The doses of four airlines were calculated by the Civil Aeromedical Research Institute (CARI) code and the European Program package for the Calculation of Aviation Route Doses (EPCARD) code. The difference of two codes was about 15 to 25%. Japanese Internet System for Calculation of Aviation Route Doses (JISCAED) has been developed by Japan. (S.Y.)

X-ray exposures to dental patients

International Nuclear Information System (INIS)

McKlveen, J.W.

1980-01-01

An elastic mask worn by patients and a skeleton encased in plastic were instrumented with LiF thermoluminescent dosimeters to determine radiation exposures delivered from full-face diagnostic dental X-rays. Measurements were made using various panoramic radiographical and periapical machines. Locations of interest included skin surface, eyes, upper and lower teeth and thyroid. Exposures in the 100 mR range were common and a maximum of over 6000 mR was measured in the teeth region during a full-face examination with a periapical unit. In general, exposures received from periapical equipment were several times those obtained from panoramic devices. (author)

Calculation of point isotropic buildup factors of gamma rays for water and lead

Directory of Open Access Journals (Sweden)

A. S. H.

2001-12-01

Full Text Available   Exposure buildup factors for water and lead have been calculated by the Monte-Carlo method for an isotropic point source in an infinite homogeneous medium, using the latest cross secions available on the Internet. The types of interactions considered are ,photoelectric effect, incoherent (or bound-electron Compton. Scattering, coherent (or Rayleigh scattering and pair production. Fluorescence radiations have also been taken into acount for lead. For each material, calculations were made at 10 gamma ray energies in the 40 keV to 10 MeV range and up to penetration depths of 10 mean free paths at each energy point. The results presented in this paper can be considered as modified gamma ray exposure buildup factors and be used in radiation shielding designs.

Radiation exposure in X-ray angiography and comparisons between digital and conventional methods of imaging

International Nuclear Information System (INIS)

Schaberg, J.

1987-01-01

The more recent developments and techniques in the field of angiography are examined for associated radiation exposure risks for patients and investigators and then compared to the conventional methods of angiography. It could be shown that digital subtraction angiography is generally associated with a lesser risk of somatic exposure of the patient, provided that the equipment used offers an adjustable useful-beam range and focus. The fact that above-table X-ray tubes are now generally replaced with X-ray systems installed under the examination table permits the relatively high doses, to which investigators are exposed during angiography, to be reduced by a factor of 3. (DG) [de

Calculation on cosmic-ray muon exposure rate in non-walled concrete buildings

International Nuclear Information System (INIS)

Fujitaka, Kazunobu; Abe, Siro

1984-01-01

Computer simulations on the exposure indoors from cosmic ray muons were practiced in the framework of non-scattering and non-cascade assumptions. The model buildings were two-dimensional, rectangular, and were made of a normal concrete. A stratified structure was assumed in each building, where no mezzanine was considered. Walls were not taken into account yet. The distributions of the exposure rates in 26-story buildings were illustrated in contour maps for various sets of parameters. All of them gave basically archlike patterns. Analyses of the results showed that the exposure rate is affected most largely by the floor board thickness. The ceiling height would be an insignificant factor for short buildings. The min/max ratio of the muon exposure rate in a moderate size building was estimated to be more than 0.7. (author)

Differences of X-ray exposure between X-ray diagnostics with a conventional X-ray screen-system and with an image-intensifier-television-unit

International Nuclear Information System (INIS)

Loehr, H.; Vogel, H.; Reinhart, J.; Jantzen, R.

1977-01-01

During X-ray diagnostics of patients in the II. Medizinische Poliklinik the X-ray exposure was determined. It corresponded to the data described in literature. Two groups were compared: 518 patients examined with a conventional X-ray screen-system and 642 patients examined with an image-intensifier-television-system. The results demonstrated that with exception of thoracical X-ray examination the replacing of the old system by the television system brought a remarkable increase of the X-ray exposure. The doses depended of the patients constitution to a high degree. (orig.) [de

Calibration of diagnostic x-ray machines using radiation exposure and radiographic parameters

International Nuclear Information System (INIS)

Agba, E.H.; Uloko, P. I.; Tyovenda, A. A.

2011-01-01

Calibration of diagnostic x-ray machines using radiation exposure and radiographic parameters of the x-ray machines has been carried out. Three phase diagnostic x-ray machines situated at Federal Medical Centre, Makurdi, General Hospital, Otukpo and Christian Hospital, Mkar were used for the calibration work. The radiation meter was used to measure x-ray radiation exposure. The result of this work demonstrates mR/mAs=C(KV p ) that there exist a power law relation of the form between the radiation exposure and the radiographic parameters of diagnostic x-ray machines, which can be used to estimate patient exposure during routine x-ray diagnostic examinations for wide range of operating parameters. The values of the power exponent n, constant c and total filtrations of the diagnostic x-ray machines have been estimated. These values for the diagnostic x-ray machines at the Federal Medical Centre, Makurdi are: 2.14, 0.88 and 2.77 respectively, for the one at the General Hospital, Otukpo are: 2.07, 0.76 and 2.68 respectively and that of the Christian Hospital, Mkar are: 2.01,0.69 and 2.61 respectively.

Exposure Factors Resources: Contrasting EPA’s Exposure Factors Handbook with International Sources (Journal Article)

Science.gov (United States)

Efforts to compile and standardize exposure human factors have resulted in the development of a variety of resources available to the scientific community. For example, the U.S. EPA developed the Exposure Factors Handbook and Child-specific Exposure Factors Handbook to promote c...

Theoretical determination of spectrum-exposure rate conversion operator of HPGe detector and its application to the measurement of environmental gamma-ray exposure rate

International Nuclear Information System (INIS)

Park, Ch.M.; Choi, B.I.; Kwak, S.S.; Ji, P.K.; Kim, T.W.; Park, Y.W.; Yoon, B.K.

1993-01-01

A conversion operator between spectrum and exposure rate, using a portable HPGe detector for environmental radiation monitoring, was determined theoretically under the assumption of uniform distribution of radiation source on the ground surface. The measurement results were compared with those of a pressurized ionization chamber. The results obtained with the HPGe detector were slightly lower. The method can be easily applied to any gamma ray detector to obtain a spectrum - exposure-rate conversion factor for computing the exposure rate of environmental gamma radiation. (N.T.) 15 refs.; 6 figs.; 3 tabs

A hard x-ray prototype production exposure station at NSLS

International Nuclear Information System (INIS)

Johnson, E.D.; Milne, J.C.

1997-07-01

Exposures conducted at the NSLS R and D beamline (X-27B) for High Aspect Ratio Precision Manufacture have proven sufficiently successful that the authors are constructing a dedicated hard x-ray exposure beamline. The new beamline (X-14B) provides an exposure field ∼ 120 mm wide, three times larger than that of X-27B. The scanner is based on the hydraulic system from the X-27B program. It is optimized for planar exposures and takes advantage of the full 525 mm stroke available. Exposures of multiple substrates and masks will be possible, with the fixturing supporting mounting of substrate holders from other groups (ALS, APS, CAMD, and UW). The function of this beamline is to establish a hard x-ray exposure station where manufacturing scale protocols can be developed and ultimately exploited for production runs

A paediatric X-ray exposure chart

Energy Technology Data Exchange (ETDEWEB)

Knight, Stephen P, E-mail: stephen.knight@health.qld.gov.au [Department of Medical Imaging, Royal Children' s Hospital, Brisbane, Queensland (Australia)

2014-09-15

The aim of this review was to develop a radiographic optimisation strategy to make use of digital radiography (DR) and needle phosphor computerised radiography (CR) detectors, in order to lower radiation dose and improve image quality for paediatrics. This review was based on evidence-based practice, of which a component was a review of the relevant literature. The resulting exposure chart was developed with two distinct groups of exposure optimisation strategies – body exposures (for head, trunk, humerus, femur) and distal extremity exposures (elbow to finger, knee to toe). Exposure variables manipulated included kilovoltage peak (kVp), target detector exposure and milli-ampere-seconds (mAs), automatic exposure control (AEC), additional beam filtration, and use of antiscatter grid. Mean dose area product (DAP) reductions of up to 83% for anterior–posterior (AP)/posterior–anterior (PA) abdomen projections were recorded postoptimisation due to manipulation of multiple-exposure variables. For body exposures, the target EI and detector exposure, and thus the required mAs were typically 20% less postoptimisation. Image quality for some distal extremity exposures was improved by lowering kVp and increasing mAs around constant entrance skin dose. It is recommended that purchasing digital X-ray equipment with high detective quantum efficiency detectors, and then optimising the exposure chart for use with these detectors is of high importance for sites performing paediatric imaging. Multiple-exposure variables may need to be manipulated to achieve optimal outcomes.

AIRGAMMA, External Gamma-Ray Exposure from Radioactive Cloud

International Nuclear Information System (INIS)

Hidaka, Akihide; Iijima, Tshinori

1989-01-01

1 - Description of program or function: AIRGAMMA calculates quickly the external exposure to gamma rays from a radioactive cloud. 2 - Method of solution: The external exposure is calculated by interpolating the normalized doses providing on the basis of the Gaussian plume model. 3 - Restrictions on the complexity of the problem: Memory requirement is 30 Kbytes

Combined exposure of ELF magnetic fields and X-rays increased mutant yields compared with X-rays alone in pTN89 plasmids

International Nuclear Information System (INIS)

Koyama, Shin; Nakahara, Takehisa; Sakurai, Tomonori; Komatsubara, Yoshiki; Miyakoshi, Junji; Isozumi, Yasuhito

2005-01-01

We have examined mutations in the supF gene carried by pTN89 plasmids in Escherichia coli (E. coli) to examine the effects of extremely low frequency magnetic fields (ELFMFs) and/or X-rays to the plasmids. The plasmids were subjected to sham exposure or exposed to an ELFMF (5 mT), with or without X-ray irradiation (10 Gy). For the combined treatments, exposure to the ELFMF was immediately before or after X-ray irradiation. The mutant fractions were 0.94 x 10 -5 for X-rays alone, 1.58 x 10 -5 for an ELFMF followed by X-rays, and 3.64 x 10 -5 for X-rays followed by an ELFMF. Increased mutant fraction was not detected following exposure to a magnetic field alone, or after sham exposure. The mutant fraction for X-rays followed by an ELFMF was significantly higher than those of other treatments. Sequence analysis of the supF mutant plasmids revealed that base substitutions were dominant on exposure to X-rays alone and X-rays plus an ELFMF. Several types of deletions were detected in only the combined treatments, but not with X-rays alone. We could not find any mutant colonies in sham irradiated and an ELFMF alone treatment, but exposure to ELFMFs immediately before or after X-ray irradiation may enhance the mutations. Our results indicate that an ELFMF increases mutation and alters the spectrum of mutations. (author)

Excessive exposures of diagnostic X-ray workers in India

International Nuclear Information System (INIS)

Ambiger, T.Y.; Shenoy, K.S.; Patel, P.H.

1980-01-01

The excessive exposures (i.e. exceeding 400 mrems per fortnight) of diagnostic X-ray workers revealed under the countrywide personnel monitoring programme in India have been analysed. The analysis covers the data collected over a period of ten years during 1965-1974. The radiation workers in medical X-ray diagnostic group receiving an excess dose are found to be less than 1%. Each case of the excess dose is throughly investigated and nongenuine cases are separated and causes for genuine excessive exposures are traced. The causes and the corrective measures are enumerated. (M.G.B.)

American National Standard: neutron and gamma-ray flux-to-dose rate factors

International Nuclear Information System (INIS)

Anon.

1977-01-01

This Standard presents data recommended for computing biological dose rates due to neutron and gamma-ray radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are given; the energy range for the gamma-ray conversion factors is 0.01 to 15 MeV. Specifically, this Standard is intended for use by shield designers to calculate wholebody dose rates to radiation workers and the general public. Establishing dose-rate limits is outside the scope of this Standard. Use of this Standard in cases where the dose equivalents are far in excess of occupational exposure guidelines is not recommended

Childhood cancer after prenatal exposure to diagnostic X-ray examinations in Britain

International Nuclear Information System (INIS)

Mole, R.H.

1990-01-01

Detailed data were provided by the Oxford Survey of Childhood Cancer OSCC on deaths from childhood cancer in Britain after irradiation of the fetus during diagnostic radiology of the mother. In each age group at death, 0-5, 6-9 and 10-15 years, excess cancer deaths decreased suddenly for births in and after 1958. A major factor was concerted action initiated in 1956 to reduce radiation exposure of fetal gonads for fear of genetic hazards. Dose reduction was achieved during 1957 and early 1958 by reducing the rising rate of obstetric radiography and by virtually abandoning pelvimetry as that had been understood. In the 1970s the rate of X-raying increased again and so did cancer risk but not significantly. Direct evidence that diagnostic X-rays can cause childhood cancer is the similar excess rate per X-ray in twins and singleton births when X-raying rate is 5-6 times higher in twins. (author)

Exploring Global Exposure Factors Resources for Use in Consumer Exposure Assessments

Science.gov (United States)

Zaleski, Rosemary T.; Egeghy, Peter P.; Hakkinen, Pertti J.

2016-01-01

This publication serves as a global comprehensive resource for readers seeking exposure factor data and information relevant to consumer exposure assessment. It describes the types of information that may be found in various official surveys and online and published resources. The relevant exposure factors cover a broad range, including general exposure factor data found in published compendia and databases and resources about specific exposure factors, such as human activity patterns and housing information. Also included are resources on exposure factors related to specific types of consumer products and the associated patterns of use, such as for a type of personal care product or a type of children’s toy. Further, a section on using exposure factors for designing representative exposure scenarios is included, along with a look into the future for databases and other exposure science developments relevant for consumer exposure assessment. PMID:27455300

Dose-to-risk conversion factors for low-level tritium exposures

International Nuclear Information System (INIS)

Straume, T.

1992-01-01

During the past decade, a large number of radiobiological studies have become available for tritium-many of them focusing on the relative biological effectiveness (RBE) of tritium beta rays. These and previous studies indicate that tritium in body water produces the same spectrum of radiogenic effects, e.g., cancer, genetic effects, developmental abnormalities, and reproductive effects, observed following whole-body exposure to penetrating radiations such as gamma rays and x rays. The only significant difference in biological response between tritium beta-rays and the other common low linear-energy transfer (LET) radiations, such as gamma rays and x rays, appears to be the greater biological effectiveness of tritium beta rays. For example, tritium in the oxide form (HTO) is about 2 to 3 times more effective at low doses or low dose rates than gamma rays from 137 Cs or 60 CO (Straume, 1991). When tritium is bound to organic molecules, RBE values may be somewhat larger than those for HTO. It is now clear from the wealth of tritium data available that RBEs for tritium beta rays are higher than the quality factor of unity generally used in radiation protection

Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization

International Nuclear Information System (INIS)

Holmes, D.R. Jr.; Bove, A.A.; Wondrow, M.A.; Gray, J.E.

1986-01-01

A newly developed video x-ray progressive scanning system improves image quality, decreases radiation exposure, and can be added to any pulsed fluoroscopic x-ray system using a video display without major system modifications. With use of progressive video scanning, the radiation entrance exposure rate measured with a vascular phantom was decreased by 32 to 53% in comparison with a conventional fluoroscopic x-ray system. In addition to this substantial decrease in radiation exposure, the quality of the image was improved because of less motion blur and artifact. Progressive video scanning has the potential for widespread application to all pulsed fluoroscopic x-ray systems. Use of this technique should make cardiac catheterization procedures and all other fluoroscopic procedures safer for the patient and the involved medical and paramedical staff

Risk assessment of medical exposure in X-ray examinations of children

Directory of Open Access Journals (Sweden)

I. G. Shatsky

2017-01-01

Full Text Available The use of the effective dose (the concept of which was developed for radiation protection of workers and public and the nominal risk coefficients, averaged by sex and age, to assess the radiation risks of medical exposure has some significant limitations. Age and sex distribution of the staff and the entire population may be quite different from the sex and age distribution of patients undergoing medical exposure. Moreover, the structure of the age and sex of patients may be different for various medical examinations. There are simplified methods for evaluating individual risk for patients undergoing medical exposure. The methods are based on the effective dose evaluation and those take in to account age and gender. A more accurate assessment of lifetime risk of delayed stochastic effects for health of the patient is achieved by using the organ doses and the age and gender risk factors. The aim of this work was evaluation of the lifetime risk of long-term stochastic health effects for different gender and age groups of children undergoing various radiographic investigations by using organ doses and the age and gender risk factors, and subsequent classification in accordance with generally accepted international risk scale. Data from surveys of33 X-ray units in 29 specialized pediatric health care organizations in Russia were used in the work. Organ doses and patient’s effective doses were calculated on the basis of the defined for each x-ray machine typical modes for the 12 radiographic procedures (X-ray exam of the skull, chest, cervical spine, thoracic spine, lumbar spine–all in two projections – of the abdomen and pelvis – both in one projectionusing a computer program PCXMC., Radiation risks for selected studies were estimated using the obtained organ doses and the age and gender risk factors calculated for the Russian population. The radiation risks were classified according to the international scale of the risks. It was found

Design And Measurement Of Radiation Exposure Rates At An X-Ray Diagnostic Radiological Unit

International Nuclear Information System (INIS)

Tito-Sutjipto

2003-01-01

Every radiation employees suffers radiation exposure risk while doing his job. It is important therefore to investigate the occupational health and safety of radiation employees on its relationship with the design and measurement of radiation exposure rates at an X-ray diagnostic radiological unit in this work, a case study was held on the radiological unit at BP-4 Yogyakarta for patient diagnostics, This research armed to investigate the relationship between the design of radiological unit for X-ray diagnostics and the location of the X-ray machine, based on the distance variable and radiation exposure rate during patient diagnostics. This was performed using radiological unit design data for X-ray diagnostics and the measurement of radiation exposure rates throughout patient diagnostics. The design data can then be used for determining the requirement of primary and secondary shielding materials for radiological unit as well as a calculation basis of radiation exposure rates during patient diagnostics. From the result of the research, it can be concluded that from the occupational health and safety point of view, radiation exposure around the X-ray machines are fairly good, both for the shielding materials in each X-ray room and the radiation exposures received by the workers, because they are far beyond the maximum permittable average limit (16.67 m R/days). (author)

Relationship medical exposure in X-ray diagnosis and loading factor and film/screen system for reduction exposure dose in Aomori. An analysis based on the results of questionnaire

International Nuclear Information System (INIS)

Kon, Masanori; Fukushi, Shouji; Oota, Fumio; Kawamura, Kouji; Shinohe, Tetsuo; Suwa, Kouki; Fujii, Kiyosuke; Yamagami, Hirofumi

2000-01-01

A fact-finding questionnaire survey on medical exposure in Aomori Prefecture was conducted in September 1998. Of the 23 exposed sites in the body investigated, exposure at 17 sites in adults was investigated in terms of the type of high-voltage generator, imaging conditions (X-ray tube voltage, electric current, exposure time, etc.), photosensitive materials and relative photosensitivity, and entrance surface doses. At 6 of the 17 exposed sites, the relationships between these technical conditions and entrance surface doses were analyzed to consider further reduction of medical exposure. The most frequently used high-voltage generators were inverter generators (about 52%). In many institutions, additional filters were utilized for high-voltage imaging of the chest. Highly sensitive green-emission materials were the most frequently used photosensitive materials (73%). These findings indicate that many institutions are attempting to reduce exposure. Entrance surface doses varied greatly among institutions: and a 100-fold difference was observed in exposure to the chest, Martius, and the pelvis. Further efforts to lower entrance surface doses are therefore necessary to reduce medical exposure. Negative correlations were observed between electric voltage, electric current, and exposure time. Examination of the relationships between entrance surface doses, electric current, and exposure time yielded positive correlations. However, the entrance surface doses may not have been properly calculated in some institutions, and examination of the relationship between the relative sensitivity of the sensitive material and entrance surface doses showed great variability in entrance surface doses between institutions. Based on the above results, it is concluded that further reduction of medical exposure is possible, not only by improving the accuracy of X-ray units/devices, but by choosing a more appropriate of conditions to perform radiography. (K.H.)

A real-time regional adaptive exposure method for saving dose-area product in x-ray fluoroscopy

International Nuclear Information System (INIS)

Burion, Steve; Funk, Tobias; Speidel, Michael A.

2013-01-01

Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An imaging frame is obtained by acquiring and reconstructing up to 8000 detector images, each viewing only a small portion of the patient. Regional adaptive exposure was implemented by varying the exposure of the detector images depending on the local opacity of the object. A family of phantoms ranging in size from infant to obese adult was imaged in anteroposterior view with and without adaptive exposure. The DAP delivered to each phantom was measured in each case, and noise performance was compared by generating noise arrays to represent regional noise in the images. These noise arrays were generated by dividing the image into regions of about 6 mm 2 , calculating the relative noise in each region, and placing the relative noise value of each region in a one-dimensional array (noise array) sorted from highest to lowest. Dose-area product savings were calculated as the difference between the ratio of DAP with adaptive exposure to DAP without adaptive exposure. The authors modified this value by a correction factor that matches the noise arrays where relative noise is the highest to report a final dose-area product savings. Results: The average dose-area product saving across the phantom family was (42 ± 8)% with the highest dose-area product saving in the child-sized phantom (50%) and the lowest in the phantom mimicking an obese adult (23%). Conclusions: Phantom measurements indicate that a regional adaptive exposure method can produce large DAP savings without compromising

Phototimer for automatic control of x-ray exposure, PT-20A

Energy Technology Data Exchange (ETDEWEB)

Ohno, H; Itoh, K; Ogura, I; Yasuhara, H; Sugimoto, H [Toshiba Corp., Kawasaki, Kanagawa (Japan)

1979-02-01

The phototimer as an exposure control device is now required to have higher accuracy and wider range of control to comply with the recent trends of x-ray diagnosis, such as toward short-time exposure due to increased output power of x-ray apparatus and toward one-man operation. In order to meet the requirement, the x-ray characteristics of the components of the phototimer have been examined, and computer simulation of x-ray spectra and dynamic characteristics of every component have been investigated, in pursuit of the essential characters of phototimers. On the basis of these analytical investigations, the phototimer PT-20A is so designed as to compensate for density deviation under various kVp and object thickness: uniform density has been obtained under practical radiographic conditions.

Implementation of a primary standard for a x-ray exposure

International Nuclear Information System (INIS)

peixoto, J.G.P.

1991-04-01

In the scientific program of the National Laboratory for Ionizing Radiation Metrology of the Instituto de Radioprotecao e Dosimetria, which belongs to the Comissao Nacional de Energia Nuclear, a free-air ionization chamber should be established as an exposure primary standard for X-rays of 100 K V to 250 K V of potential range. Preliminary results showed that the available free-air ionization chamber was suitable to be used. The absolute measurement of the radiation quantity exposure, is performed with a free-air ionization chamber. Its geometrical volume, which allows the determination of the air mass, is defined by the effective aperture area and by the length of the region where an electrical field is applied. Most of the ions produced in such volume are collected as an ionization current. Parameters related to the measurement of the quantity exposure were evaluated, such as: air absorption, scattering inside the ionization chamber, saturation, beam homogeneity, influence of beam size and influences of temperature, humidity and atmospheric pressure. Preliminary determination of correction factors has showed good results with 99.9% of repeatability and has demonstrated the reliability of the checked chamber as a standard instrument. (author)

Exposure to rays and radiation hazards in connection with diagnostic X-ray procedures in children

International Nuclear Information System (INIS)

Protzer, K.

1988-01-01

In this study, figures and data about radiation exposures for diagnostic purposes are surveyed that were collected in connection with X-ray procedures in children. The data were sorted according to body regions and techniques required for their examination so as to permit separate analyses of procedures in the urogenital tract (intravenous urogramme, micturition cystourethrography), thorax (angiocardiogramme, thoractic aortogramme, examinations using cardiac catheters), gastrointestinal system (fluoroscopy and contrast-enhanced irrigoscopy), pelvis (survey radiography), skull (computed tomography) as well as in miscellaneous group of further origins. The second part of the report discusses the uncertainties surrounding the assessment of radiation hazards and indicated radiation doses. A formula is represented for the calculation of life-time reductions that can be applied to any type of cancer and embraces a number of factors like life expectancy at age X, the patient's age at the time of radiotherapy, the five-year-survival rate for the condition under investigation and the diseased organ. At the end of the study, some methods are pointed out that may be helpful in limiting radiation exposure. (KST) [de

[Evaluation of dental X-ray apparatus in terms of patient exposure to ionizing radiation].

Science.gov (United States)

Olszewski, Jerzy; Wrzesień, Małgorzata

2017-06-27

The use of X-ray in dental procedures causes exposure of the patient to ionizing radiation. This exposure depends primarily on the parameters used in tooth examination. The aim of the study was to determine the patients exposure and to assess the technical condition of X-ray tubes. Seventeen hundred dental offices were covered by the questionnaire survey and 740 questionnaires were sent back. Direct measurements were performed in 100 units by using the thermoluminescent detectors and X-ray films. The results showed that the most commonly used exposure time is 0.22±0.16 s. The average entrance dose for the parameters used most commonly by dentists is 1.7±1.4 mGy. The average efficiency of X-ray tube estimated on the basis of exposures is 46.5±23.7 μGy/mAs. The study results indicate that the vast majority of X-ray tubes meet the requirements specified in the binding regulations. Med Pr 2017;67(4):491-496. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Development of a concept for radiation patients exposure assessment during dental X-ray examinations and statistical data acquisition for the determination of a diagnostic reference value

International Nuclear Information System (INIS)

Kueppers, C.; Sering, M.; Poppe, B.; Poplawski, A.; Looe, H.K.; Beyer, D.; Pfaffenberger, A.; Chofor, N.; Eenboom, F.

2012-01-01

The research project on the development a concept for radiation patients exposure assessment during dental X-ray examinations and statistical data acquisition for the determination of a diagnostic reference value includes the following issues: Fundamental facts: dental X-ray examination techniques, dose relevant factors and characteristics during X-ray examinations, radiation exposed organs during dental X-ray examinations, dose assessment based on phantoms. Materials and methodologies of the project: TLD measurements using the phantom, calculation of the effective dose during dental X-ray examinations, properties and settings of the reference facilities for the determination of radiation exposure, selection of dental offices, dosimetric measurements, data acquisition and statistical evaluation. Results of dosimetric examinations: results of dosimetric measurements at reference facilities, results of dosimetric measurements in dental offices. Discussion of the concept for the determination of the radiation exposure during dental X-ray examinations.

Radiation exposure of the Yazd Population from medical conventional X-ray examinations

International Nuclear Information System (INIS)

Bouzarjomehri, F.; Zare, M. H.; Dashti, M. H.

2007-01-01

Radiation dose knowledge through X-ray examinations and their distribution in Iran provides useful guidance on patient dose reduction. The results of the entrance skin dose (ESD s ) of five common radiographs in all radiology centers in Yazd province were reported in our previous study (2003). In the present study we have evaluated the collective effective dose of conventional X-ray examinations, as well as the annual per caput of Yazd population.Materials and Methods: The annual frequencies of 18 different types of conventional radiology examinations during April 2005 to March 2006 were recorded from all 35 radiology centers in Yazd province. The exposure conditions consisted of kVp, mAs, and Focus surface distance (FSD) of the examinations for the mode of exposure in each X-ray unit. 620 ESD were measured by diode dosimeter in 35 hospitals and clinics. The real exposure kVp for each radiology unit was measured by a Molt-0-Meter. The conversion coefficient (effective dose - ESD ratio) for each radiology examination was determined by using SR262 tables. Finally, the patients' effective dose was calculated by multiplying the conversion factor to the ESD. Results: The patients' annual collective effective dose due to the conventional radiology examinations was 31.159 man-Sv (0.03 mSv per inhabitant). The frequency of examinations was 311813 i.e. 0.36 examinations per head of the population for one year. Conclusion: According to our findings, the effective per caput dose seems to be optimally relative to HCL-II countries, which may be due to low mean effective dose that could obscure high examination frequency. The number of radiology conventional examinations and frequency of radiologist per1000 population of Yazd was more and lower than HCL-II countries respectively. Thus the justification of radiography requests in this province must be revised

Radiation exposure to chest X-rays in the neonatal nursery

International Nuclear Information System (INIS)

Takeuchi, Toshio; Itabashi, Kazuo; Kawaguchi, Shigeru; Suzuka, Takahisa; Okuyama, Kazuo

1989-01-01

To measure how much very low birth-weight infants are exposed to chest X-rays during nursery, skin doses were calculated using phantoms under the same condition as that used in chest X-rays. Skin doses obtained were multiplied by the number of X-rays performed in 86 very low birth-weight infants (mean birth weight+-SD, 1163.0+-232.8 g; mean gestational age+-SD, 29.3+-3.0 week). Exposure doses per film ranged from 4.9 to 14.4 mR, with a mean dose of 6.1+-2.0 mR. Exposure doses per neonate ranged from 6.3 to 794.3 mR, with a mean dose of 170.4+-151.5 mR. The number of films per neonate ranged from one to 107, with a mean of 28.0+-24.9. Eighty-seven percent of X-rays were performed when the body weight was 1,500 g or less. Fourteen patients received 300 mR or more that may be the potential dose of radiation effects. (Namekawa, K)

Anatomy-based transmission factors for technique optimization in portable chest x-ray

Science.gov (United States)

Liptak, Christopher L.; Tovey, Deborah; Segars, William P.; Dong, Frank D.; Li, Xiang

2015-03-01

Portable x-ray examinations often account for a large percentage of all radiographic examinations. Currently, portable examinations do not employ automatic exposure control (AEC). To aid in the design of a size-specific technique chart, acrylic slabs of various thicknesses are often used to estimate x-ray transmission for patients of various body thicknesses. This approach, while simple, does not account for patient anatomy, tissue heterogeneity, and the attenuation properties of the human body. To better account for these factors, in this work, we determined x-ray transmission factors using computational patient models that are anatomically realistic. A Monte Carlo program was developed to model a portable x-ray system. Detailed modeling was done of the x-ray spectrum, detector positioning, collimation, and source-to-detector distance. Simulations were performed using 18 computational patient models from the extended cardiac-torso (XCAT) family (9 males, 9 females; age range: 2-58 years; weight range: 12-117 kg). The ratio of air kerma at the detector with and without a patient model was calculated as the transmission factor. Our study showed that the transmission factor decreased exponentially with increasing patient thickness. For the range of patient thicknesses examined (12-28 cm), the transmission factor ranged from approximately 21% to 1.9% when the air kerma used in the calculation represented an average over the entire imaging field of view. The transmission factor ranged from approximately 21% to 3.6% when the air kerma used in the calculation represented the average signals from two discrete AEC cells behind the lung fields. These exponential relationships may be used to optimize imaging techniques for patients of various body thicknesses to aid in the design of clinical technique charts.

Investigation of Deuterium Loaded Materials Subject to X-Ray Exposure

Science.gov (United States)

Benyo, Theresa L.; Steinetz, Bruce M.; Hendricks, Robert C.; Martin, Richard E.; Forsley, Lawrence P.; Daniels, Christopher C.; Chait, Arnon; Pines, Vladimir; Pines, Marianna; Penney, Nicholas;

Uncertainties of exposure-related quantities in mammographic x-ray unit quality control

International Nuclear Information System (INIS)

Gregory, Kent J.; Pattison, John E.; Bibbo, Giovanni

2006-01-01

Breast screening programs operate in many countries with mammographic x-ray units subject to stringent quality control tests. These tests include the evaluation of quantities based on exposure measurements, such as half value layer, automatic exposure control reproducibility, average glandular dose, and radiation output rate. There are numerous error sources that contribute to the uncertainty of these exposure-related quantities, some of which are unique to the low energy x-ray spectrum produced by mammographic x-ray units. For each of these exposure-related quantities, the applicable error sources and their magnitudes vary, depending on the test equipment used to make the measurement, and whether or not relevant corrections have been applied. This study has identified and quantified a range of error sources that may be used to estimate the combined uncertainty of these exposure-related quantities, given the test equipment used and corrections applied. The uncertainty analysis uses methods described by the International Standards Organization's Guide to the Expression of Uncertainty in Measurement. Examples of how these error sources combine to give the uncertainty of the exposure-related quantities are presented. Using the best test equipment evaluated in this study, uncertainties of the four exposure-related quantities at the 95% confidence interval were found to be ±1.6% (half value layer), ±0.0008 (automatic exposure control reproducibility), ±2.3% (average glandular dose), and ±2.1% (radiation output rate). In some cases, using less precise test equipment or failing to apply corrections, resulted in uncertainties more than double in magnitude

Exposure reduction in general dental practice using digital x-ray imaging system for intraoral radiography with additional x-ray beam filter

International Nuclear Information System (INIS)

Shibuya, Hitoshi; Mori, Toshimichi; Hayakawa, Yoshihiko; Kuroyanagi, Kinya; Ota, Yoshiko

1997-01-01

To measure exposure reduction in general dental practice using digital x-ray imaging systems for intraoral radiography with additional x-ray beam filter. Two digital x-ray imaging systems, Pana Digital (Pana-Heraus Dental) and CDR (Schick Technologies), were applied for intraoral radiography in general dental practice. Due to the high sensitivity to x-rays, additional x-ray beam filters for output reduction were used for examination. An Orex W II (Osada Electric Industry) x-ray generator was operated at 60 kVp, 7 mA. X-ray output (air-kerma; Gy) necessary for obtaining clinically acceptable images was measured at 0 to 20 cm in 5 cm steps from the cone tip using an ionizing chamber type 660 (Nuclear Associates) and compared with those for Ektaspeed Plus film (Eastman Kodak). The Pana Digital system was used with the optional filter supplied by Pana-Heraus Dental which reduced the output to 38%. The exposure necessary to obtain clinically acceptable images was only 40% of that for the film. The CDR system was used with the Dental X-ray Beam Filter Kit (Eastman Kodak) which reduced the x-ray output to 30%. The exposure necessary to obtain clinically acceptable images was only 20% of that for the film. The two digital x-ray imaging systems, Pana Digital and CDR, provided large dose savings (60-80%) compared with Ektaspeed Plus film when applied for intraoral radiography in general dental practice. (author)

Analysis of patients' X-ray exposure in 146 percutaneous radiologic gastrostomies; Analyse der Strahlenexposition fuer Patienten bei 146 perkutanen radiologischen Gastrostomien

Energy Technology Data Exchange (ETDEWEB)

Petersen, Tim-Ole; Reinhardt, Martin; Fuchs, Jochen; Gosch, Dieter; Surov, Alexey; Stumpp, Patrick; Kahn, Thomas; Moche, Michael [Univ. Hospital Leipzig (Germany). Dept. of Diagnostic and Interventional Radiology

2017-09-15

Analysis of patient's X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, and fluoroscopy time (FT) were correlated with the used x-ray systems (Flatpanel Detector (FD) vs. Image Itensifier (BV)) and the necessity for periprocedural placement of a nasogastric tube. Additionally, the effective X-ray dose for PRG placement using fluoroscopy (DL), computed tomography (CT), and cone beam CT (CBCT) was estimated using a conversion factor. The median DFP of PRG-placements under fluoroscopy was 163 cGy{sup *}cm{sup 2} (flat panel detector systems: 155 cGy{sup *}cm{sup 2}; X-ray image intensifier: 175 cGy{sup *}cm{sup 2}). The median DLZ was 2.2min. Intraprocedural placement of a naso- or orogastric probe (n=68) resulted in a significant prolongation of the median DLZ to 2.5min versus 2min in patients with an already existing probe. In addition, dose values were analyzed in smaller samples of patients in which the PRG was placed under CBCT (n=7, median DFP=2635 cGy{sup *}cm{sup 2}), or using CT (n=4, median DLP=657mGy{sup *}cm). Estimates of the median DFP and DLP showed effective doses of 0.3mSv for DL-assisted placements (flat panel detector 0.3mSv, X-ray image converter 0.4mSv), 7.9mSv using a CBCT - flat detector, and 9.9mSv using CT. This corresponds to a factor 26 of DL versus CBCT, or a factor 33 of DL versus CT. In order to minimize X-ray exposure during PRG-procedures for patients and staff, fluoroscopically-guided interventions should employ flat detector systems with short transmittance sequences in low dose mode and with slow image frequency. Series recordings can be dispensed with. The intraprocedural placement of a naso- or orogastric probe significantly extends FT, but has little effect on the overall dose of the

Cost Benefit Optimization of the Israeli Medical Diagnostic X-Ray Exposure

International Nuclear Information System (INIS)

Ben-Shlomo, A.; Shlesinger, T.; Shani, G.; Kushilevsky, A.

1999-01-01

Diagnostic and therapeutic radiology is playing a major role in modern medicine. A preliminary survey was carried out during 1997 on 3 major Israeli hospitals in order to assess the extent of exposure of the population to medical x-rays (1). The survey has found that the annual collective dose of the Israeli population to x-ray medical imaging procedures (excluding radio-therapy) is about 7,500 Man-Sv. The results of the survey were analyzed in order to. 1. Carry out a cost-benefit optimization procedure related to the means that should be used to reduce the exposure of the Israeli patients under x-ray procedures. 2. Establish a set of practical recommendations to reduce the x-ray radiation exposure of patients and to increase the image quality. . Establish a number of basic rules to be utilized by health policy makers in Israel. Based on the ICRP-60 linear model risk assessments (2), the extent of the annual risk arising A.om the 7,500 Man-Sv medical x-ray collective dose in Israel has been found to be the potential addition of 567 cancer cases per year, 244 of which to be fatal, and a potential additional birth of 3-4 children with severe genetic damage per year. This assessment take into account the differential risk and the collective dose according to the age distribution in the Israeli exposed population, and excludes patients with chronic diseases

Energy and rate dependence of diagnostic x-ray exposure meters

International Nuclear Information System (INIS)

Wagner, L.K.; Cerra, F.; Conway, B.; Fewell, T.R.; Ohlhaber, T.R.

1988-01-01

Variations in x-ray exposure measurements among a variety of contemporary diagnostic exposure meters are investigated. Variations may result from systematic errors due to calibration, beam-quality dependence and exposure-rate dependence. It is concluded that the majority of general purpose diagnostic meters will agree to within 10% of each other if exposure rates are below 1.3 mC kg-1S-1 of air (5 R s-1) and beam qualities are typical for general purpose radiology, excluding mammography. For exposure rates comparable to those in barium enema radiography the variations can range up to 25% or more. Variations up to 40% were observed among general purpose exposure meters at mammographic beam qualities. In the mammographic range, mammographic (thin window) exposure meters varied by no more than 2%

Measurement of exposure buildup factors: The influence of scattered photons on gamma-ray attenuation coefficients

Science.gov (United States)

Mann, Kulwinder Singh

2018-01-01

Scattered photon's influence on measured values of attenuation coefficients (μm, cm2g-1) for six low-Z (effective atomic number) building materials, at three photon energies has been estimated. Narrow-beam transmission geometry has been used for the measurements. Samples of commonly used engineering materials (Cements, Clay, Lime-Stone, Plaster of Paris) have been selected for the present study. Standard radioactive sources Cs137 and Co60 have been used for obtaining γ-ray energies 661.66, 1173.24 and 1332.50 keV. The optical thickness (OT) of 0.5 mfp (mean free path) has been found the optimum optical thickness (OOT) for μm-measurement in the selected energy range (661.66-1332.50 keV). The aim of this investigation is to provide neglected information regarding subsistence of scattered photons in narrow beam geometry measurements for low-Z materials. The measurements have been performed for a wide range of sample-thickness (2-26 cm) such that their OT varies between 0.2-3.5 mfp in selected energy range. A computer program (GRIC2-toolkit) has been used for various theoretical computations required in this investigation. It has been concluded that in selected energy-range, good accuracy in μm-measurement of low-Z materials can be achieved by keeping their sample's OT below 0.5 mfp. The exposure buildup factors have been measured with the help of mathematical-model developed in this investigation.

Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue

Science.gov (United States)

Spalding, J. F.; Holland, L. M.; Prine, J. R.; Farrer, D. N.; Braun, R. G.

1972-01-01

Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower.

MODERN PECULIARITIES OF THE MEDICAL EXPOSURE LEVELS FORMING OF THE TATARSTAN REPUBLIC POPULATION DURING X-RAY PROCEDURES IMPLEMENTATION

Directory of Open Access Journals (Sweden)

S. A. Ryzhkin

2015-01-01

Full Text Available The purpose. The purpose of the investigation is an assessment of the peculiarities of forming and registration of the collective doses of patients and the population of the Tatarsatan Republic (RT from medical exposure and the development of measures for optimization of this radiation factor.Materials and methods. The analysis is based on the forms of the Federal statistical observation № 3-DOZ «Data on the exposure doses to patients obtained during medical radiological examination» (form № 3-DOZ and radiation-hygienic passports of RT for the period from 2006 to 2013.The results. Annually in RT there is an increase of the number of performed X-ray procedures, which reached the value of 6279696 (1.64 procedures per resident per year in 2013. During the reporting period (from 2006 to 2013 the structure of the performed X-ray procedures has also changed. It is observed that the percentage of fluorography procedures in the overall structure decreased from 41.3% to 31.3% at the same time the level of absolute value of annually performed fluorography procedures is stable. There is an increase in the absolute number of radiographic procedures performed during the period from 2578754 to 4072810 X-rays per year, that is 1.58 times higher. Absolute and relative values related to X-ray fluoroscopy examinations decreased from 1.1% to 0.7%. In contrast, the absolute number of annually performed X-ray computed tomography examinations (CT has increased over the period by 3.3 times and percentage of CT in overall structure of X-ray procedure is 2.7%. The number of special investigations has increased in 2.1 times, but the relative value remained at average level of 0.4% on general background of the increasing of X-ray activity in the region. This fact influenced the change in the radiation-hygienic indexes of medical radiation exposure of the population of RT. According to №3-DOZ forms and radiation-hygienic passports of the

High precision instrumentation for measuring the true exposure time in diagnostic X-ray examinations

International Nuclear Information System (INIS)

Silva, Danubia B.; Santos, Marcus A.P.; Barros, Fabio R.; Santos, Luiz A.P.

2013-01-01

One of the most important physical quantities to be evaluated in diagnostic radiology is the radiation exposure time experimented by the patient during the X-ray examination. IAEA and WHO organizations have suggested that any country must create a quality surveillance program to verify if each type of ionizing radiation equipment used in the hospitals and medical clinics are in conformity with the accepted uncertainties following the international standards. The purpose of this work is to present a new high precision methodology for measuring true exposure time in diagnostic X-ray examinations: pulsed, continuous or digital one. An electronic system named CronoX, which will be soon registered at the Brazilian Patent Office (INPI), is the equipment that provides such a high precision measurement. The principle of measurement is based on the electrical signal captured by a sensor that enters in a regeneration amplifier to transform it in a digital signal, which is treated by a microprocessor (uP). The signal treatment results in a two measured times: 1) T rx , the true X-ray exposure time; 2) T nx , the time in which the X-ray machine is repeatedly cut off during the pulsed irradiation and there is no delivery dose to the patient. Conventional Polymat X-ray equipment and dental X-ray machines were used to generate X-ray photons and take the measurements with the electronic systems. The results show that such a high precision instrumentation displays the true exposure time in diagnostic X-ray examinations and indicates a new method to be purposed for the quality surveillance programs in radiology. (author)

Hygiene implications associated with x-ray exposures to dental patients

International Nuclear Information System (INIS)

McKlveen, J.W.

1980-01-01

An elastic mask worn by patients, then a skeleton encased in plastic, was instrumented with LiF thermoluminescent dosimeters to quantify radiation exposures delivered from full-face diagnostic dental x-rays. Locations of interest included skin surface, eyes, upper and lower teeth and thyroid. Exposures in the 100 mR range were common and a maximum of over 6000 mR was measured in the teeth region during a full-face examination with a periapical unit. In general, exposures received from periapical equipment were several times those obtained from panoramic devices

Comparison of late effects of single x-ray exposure, chronic tritiated water ingestion, and chronic cesium-137 gamma exposure in mice

International Nuclear Information System (INIS)

Carsten, A.L.; Cronkite, E.P.

1979-01-01

There is concern over the possible late effects resulting from chronic exposure to tritiated water, a primary by-product of power reactors. We are comparing the genetic and somatic effects of tritiated water ingestion to acute x-ray or chronic cesium-137 gamma-ray exposures. Eight week old mice were maintaned on tritiated water in concentrations of 0.3, 1.0, and 3.0 μCi/ml. Identical animals received cesium-137 gamma exposures equivalent to that from the tritiated water. At 4 week intervals, animals were sacrificed and the hematopoietic stem cell content and cellularity of the bone marrow determined. For comparison of acute and chronic effects, one group of mice received a single whole-body x-ray exposure of 525 rads. The x-irradiated animals showed an immediate sharp decrease in marrow cellularity followed by gradual return to normal levels, with a lifelong reduction in number of marrow stem cells. Animals exposed to the two higher concentrations of tritiated water showed only slight reductions in marrow cellularity, with a lifelong reduction in hematopoietic stem cells in the bone marrow. Comparison of the external gamma exposures to chronic tritiated water ingestion indicates similar patterns. Maintenance of normal cellularity with a reduced number of stem cells in x-rayed animals was shown by tritiated thymidine cytocide to be due to the reduction in number of stem cells in the resting G/sub O/ stage. At this time it is not possible to determine whether there is a significant difference in relative biological effectiveness of tritiated water compared to cesium-137 gamma rays; however, indications are that they are similar

New results regarding gonadal exposure in urologic X-ray diagnostics

International Nuclear Information System (INIS)

Barke, R.

1977-01-01

In a dosimetric study the radiation exposure of the gonads of 130 patients is determined with condenser ionization chambers in applying intravenous urography according to the valid examination standard of the Society of Medical radiology of the GDR. Shielding the gonads with 2 mm lead equivalent the gonad dose of men is less than 30 mrem, but more than 850 mrem without shielding. The gonad dose of women computationally determined from measurements of the surface dose, is about 1,200 mrem. As the radiation exposure due to each individual radiograph was recorded, the influencing factors (film size, distance of the lower field margin from the gonads) can be determined. For the statistically significant correlation between body weight and gonad dose regression equations are given which, with standard X-ray examinations, make it possible to calculate the gonad dose for the individual case with a high degree of certainty. The analysis of intravenous urographic examinations shows that there is a greater share of female patients because this type of examination is often used as an additional diagnostic procedure in case of gynaecologic diseases. Problems of exact dosimetry at the ovary can hardly be solved

Affecting Factors of Secondhand Smoke Exposure in Korea: Focused on Different Exposure Locations.

Science.gov (United States)

Sun, Li Yuan; Cheong, Hae Kwan; Lee, Eun Whan; Kang, Kyeong Jin; Park, Jae Hyun

2016-09-01

Exposure to secondhand smoke (SHS) not only can cause serious illness, but is also an economic and social burden. Contextual and individual factors of non-smoker exposure to SHS depend on location. However, studies focusing on this subject are lacking. In this study, we described and compared the factors related to SHS exposure according to location in Korea. Regarding individual factors related to SHS exposure, a common individual variable model and location-specific variable model was used to evaluate SHS exposure at home/work/public locations based on sex. In common individual variables, such as age, and smoking status showed different relationships with SHS exposure in different locations. Among home-related variables, housing type and family with a single father and unmarried children showed the strongest positive relationships with SHS exposure in both males and females. In the workplace, service and sales workers, blue-collar workers, and manual laborers showed the strongest positive association with SHS exposure in males and females. For multilevel analysis in public places, only SHS exposure in females was positively related with cancer screening rate. Exposure to SHS in public places showed a positive relationship with drinking rate and single-parent family in males and females. The problem of SHS embodies social policies and interactions between individuals and social contextual factors. Policy makers should consider the contextual factors of specific locations and regional and individual context, along with differences between males and females, to develop effective strategies for reducing SHS exposure.

A survey of medical exposure during X-ray diagnosis in Aomori

International Nuclear Information System (INIS)

Kon, Masanori; Fukushi, Shouji; Oota, Fumio; Kawamura, Kouji; Shinohe, Tetsuo; Suwa, Kouki; Fujii, Kiyosuke; Yamagami, Hirofumi

2000-01-01

The purpose of this project was to survey medical exposure doses in Aomori Prefecture and compare them with guidance levels for X-ray diagnosis. A questionnaire survey on X-ray diagnosis was conducted at the main medical institutions in the prefecture. The questionnaire asked about technical conditions, and replies were obtained from 72.2% of the 79 institutions. The medical exposure doses (entrance surface doses) were calculated from the results of the questionnaires by the modified numerical dose determination (NDD) method. The distribution of the entrance surface doses at each site was calculated as the 1st quartile, median, 3rd quartile, average, standard deviation, maximum value and minimum value, by the quartile method. The distribution of exposed doses at each site showed a similar pattern with that of the national distribution. Some institutions used higher doses than the Japanese proposed guidance levels and International Atomic Energy Agency (IAEA) guidance levels. Re-assessment of radiographic conditions and photosensitive materials is needed to reduce exposure doses. (K.H.)

Determination of gamma-ray exposure rate from short-lived fission products under criticality accident conditions

International Nuclear Information System (INIS)

Yanagisawa, Hiroshi; Ohno, Akio; Aizawa, Eijyu

2002-01-01

For the assessment of γ-ray doses from short-lived fission products (FPs) under criticality accident conditions, γ-ray exposure rates varying with time were experimentally determined in the Transient Experiment Critical Facility (TRACY). The data were obtained by reactivity insertion in the range of 1.50 to 2.93$. It was clarified from the experiments that the contribution of γ-ray from short-lived FPs to total exposure during the experiments was evaluated to be 15 to 17%. Hence, the contribution cannot be neglected for the assessment of γ-ray doses under criticality accident conditions. Computational analyses also indicated that γ-ray exposure rates from short-lived FPs calculated with the Monte Carlo code, MCNP4B, and photon sources based on the latest FP decay data, the JENDL FP Decay Data File 2000, well agreed with the experimental results. The exposure rates were, however, extremely underestimated when the photon sources were obtained by the ORIGEN2 code. The underestimation is due to lack of energy-dependent photon emission data for major short-lived FP nuclides in the photon database attached to the ORIGEN2 code. It was also confirmed that the underestimation arose in 1,000 or less of time lapse after an initial power burst. (author)

Overview of the development of the Korean exposure factors handbook.

Science.gov (United States)

Jang, Jae-Yeon; Jo, Soo-Nam; Kim, So-Yeon; Myung, Hyung-Nam

2014-01-01

A set of exposure factors that reflects the characteristics of individual behavior capable of influencing exposure is essential for risk and exposure assessment. In 2007, the Korean Exposure Factors Handbook was, therefore, issued, driven by the need to develop reliable exposure factors representing the Korean population. The purpose of this study was to overview the development process of the Korean Exposure Factors Handbook and major recommended exposure values for the Korean population to allow information exchanges and comparison of recommended values among nations. The researchers reviewed the domestic data that could be used in the development of exposure factors, confirmed a knowledge gap, and set a priority of development by phases. A methodology to measure exposure factors was established to develop measuring techniques and test their validity. Data were processed or a survey was conducted according to the availability of data. The study thus produced recommended values for 24 exposure factors grouped by general exposure factors, food ingestion factors, and activity factors by setting up a database of exposure factors and carrying out statistical analysis. The study has significantly contributed to reducing the potential uncertainty of the risk and exposure assessment derived by the application of foreign data or research findings lacking representativeness or grounds by developing a set of exposure factors reflecting the characteristics of the Korean people. It will be necessary to conduct revisions in light of the changing statistical values of national data and the exposure factors based on Korean characteristics.

The effects of air pollution and climatic factors on atmospheric corrosion of marble under field exposure

International Nuclear Information System (INIS)

Lan, Tran Thi Ngoc; Nishimura, Rokuro; Tsujino, Yoshio; Satoh, Yukihiro; Thi Phuong Thoa, Nguyen; Yokoi, Masayuki; Maeda, Yasuaki

2005-01-01

The atmospheric corrosion of marble was evaluated in terms of SO 2 concentration as air pollution and climatic factors such as rainfall, relative humidity, temperature and so on under the field exposure. Marble of calcite type (CaCO 3 ) was exposed to outdoor atmospheric environment with and without a rain shelter at four test sites in the southern part of Vietnam for 3-month, 1- and 2-year periods from July 2001 to September 2003. The thickness loss of marble was investigated gravimetrically. X-ray diffraction and X-ray fluorescent methods were applied to study corrosion products on marble. The corrosion product of marble was only gypsum (CaSO 4 . 2H 2 O) and was washed out by rain under the unsheltered exposure condition. It was found that the most substantial factors influencing the corrosion of marble were rainfall, SO 2 concentration in the air and relative humidity. Based on the results obtained, we estimated the dose-response functions for the atmospheric corrosion of marble in the southern part of Vietnam

Update of diagnostic medical and dental x-ray exposures in Romania

Energy Technology Data Exchange (ETDEWEB)

Sorop, Ioana; Mossang, Daniela; Dadulescu, Elena [Radiation Hygiene Laboratory of Public Health Authority Dolj, 2, Constantin Lecca Street, Craiova (Romania); Iacob, Mihai Radu [University ' Alexandru Ioan Cuza' , 11, Carol I Street, 700506, Iasi (Romania); Iacob, Olga [Institute of Public Health, 14, Victor Babes Street, 700465 Iasi (Romania)], E-mail: danamossang@sanpubdj.ro

2008-12-15

This national study, the third in the last 15 years, updates the magnitude of medical radiation exposure from conventional x-ray examinations, in order to optimise the radiological protection to the population in a cost-effective manner. Effective doses from diagnostic radiology were estimated for adult and paediatric patients undergoing the 20 most important types of x-ray examination. Data were collected from 179 x-ray departments, selected by their annual workload, throughout the country. Estimates were made using two dosimetric quantities: entrance surface dose, derived from the absorbed dose in air measured by simulation of radiographic examinations, and dose-area product, measured during fluoroscopic examinations performed on adult and paediatric patients. Conversion coefficients to effective dose of the UK National Radiological Protection Board (NRPB) have been used in all calculations. The effective dose per patient from all medical x-ray examinations was 0.74 mSv and the resulting annual collective effective dose was 6930 man Sv, with annual effective dose per caput of 0.33 mSv. The current size of population exposure from diagnostic radiology is lower than the previous one by 40%, but could be about 30% higher by taking into account the estimated contribution from computed tomography (CT) procedures.

Risk factors of coronary heart disease among medical diagnostic X-ray workers

International Nuclear Information System (INIS)

Zhang Wei; Wang Jixian; Zhao Yongcheng; Li Benxiao; Fan Tiqiang; Zhao Zhigang; Lin Zhidong

2002-01-01

Objective: To investigate risk factors of coronary heart disease (CHD) in medical diagnostic X-ray workers in China, especially the relationship of CHD with occupational irradiation. Methods: A 1:2 matched case-control study was carried out. The study subjects consisted of 112 pair-matched cases and controls coming from different hospitals in China. Information about occupational and non-occupational risk factors obtained by interviewing every subjects personally. Individual doses were estimated by normalized work load method. SAS 6.12 software conditional Logistic regression method was applied to data analysis. Results: Variables such as family history of CHD (OR=17.298, P = 0.0001), history of hypertension (OR = 6.172, P = 0.0003), overweight (OR = 2.679, P = 0.0150), physical exercises (OR = 0.421, P0.0333), diabetes (OR = 7.823, P = 0.0200), radiation protection condition (OR = 3.992, P 0.0027), and accumulated radiation dose (OR = 1.612, P 0.0454) were included in the last model. Conclusions: For the medical diagnostic X-ray workers, family history of coronary heart disease, history of hypertension, diabetes, etc. are the main risk factors of CHD, and occupational exposure may be a potential risk factor. As for the mechanism, further studies are needed

Cosmic ray exposure ages of features and events at the Apollo landing sites

International Nuclear Information System (INIS)

Arvidson, R.; Crozaz, G.; Drozd, R.J.; Hohenberg, C.M.; Morgan, C.J.

1975-01-01

Cosmic ray exposure ages of lunar samples have been used to date surface features related to impact cratering and downslope movement of material. Only when multiple samples related to a feature have the same rare gas exposure age, or when a single sample has the same 81 Kr-Kr and track exposure age can a feature be considered reliably dated. Because any single lunar sample is likely to have had a complex history, assignment of ages to features based upon only one determination by any method should be avoided. Based on the above criteria, there are only five well-dated lunar features: Cone Crater (Apollo 14) 26 m.y., North Ray Crater (Apollo 16) 50 m.y., South Ray Crater (Apollo 16) 2 m.y., the emplacement of the Station 6 boulders (Apollo 17) 22 m.y., and the emplacement of the Station 7 boulder (Apollo 17) 28 m.y. Other features are tentatively dated or have limits set on their ages: Bench Crater (Apollo 12) =50 m.y. (Auth.)

Cytogenetic studies with laser or X-ray exposures

International Nuclear Information System (INIS)

Bozduganov, A.; Genkov, P.

1975-01-01

Account is given of studies involving a total of 21 peripheral blood cultures given the following treatments: exposure to 20 0.13-joule pulses from an optic quantum generator (ruby), 9; exposure to 1000 R X-rays, 9; and unexposed controls, 3. Exposures were carried out on three cultures from each experimental series at each of three time intervals, namely 24 h, 48 h, and 72 h after initiation of cultures. On any day, 40 well-spread metaphases were examined. High quality metaphases were photographed and karyotyped in conformity to the Chicago Conference criteria. In the laser experiment, chromosome aberrations were observed in 65% of methaphases analyzed vs. 5.3% in controls. Anomalies encountered included aneuploidy, with hypoploid metaphases predominating, polyploidy (triploidy, tetraploidy, and partial endoreduplication), and structural alterations. The following structural chromosome rearrangements are found: acentric fragments, mostly pairs, occasionally single, including minute chromosomes; dicentric and tricentric chromosomes; interstitial deletions; and chromosome translocations. Most varied and abundant chromosome aberrations were seen in 72-h irradiated cultures. The data presented offer a new opportunity for assessing genetic lesions after laser exposure and may help to determine threshold doses. (author)

Patient dose evaluations from medical X-ray exposure in Italy: an analysis of next data

International Nuclear Information System (INIS)

Marchetti, A.; Paganini, F.M.; Susanna, A.

1980-01-01

NEXT (Nationwide Evaluation of X-ray Trends) is a program for the evaluation of patient exposure in X-ray diagnostic tests. The program is aimed at reducing patient exposure by pin-pointing poor radiological techniques and improving them. CNEN (Comitato Nazionale per l'Energia Nucleare) and ISS (Istituto Superiore di Sanita) have been developing such a program in Italy since 1976. Up to now two regional administrations applied the method and regional operators collected the needed data in all the medical institutions in their areas. The results show a wide spread of values for all the parameters studied in the 12 X-ray projections selected. Gonad dose and skin entrance exposure were found to be spread over a range up to about two orders of magnitude. (H.K.)

Accidental exposure with X-ray diffraction equipment

International Nuclear Information System (INIS)

Montanez, O.; Blanco, D.

1991-01-01

The shutter on one of the windows of an X-ray diffraction apparatus was accidentally left open, exposing the worker to the radiation. The worker was wearing a dosimeter film, which was processed immediately to evaluate the potential risk. It was determined that the exposure rate was 350 Roentgen/minute on the skin surface, with corrections being made for the worker's thin clothing. It was concluded that in spite of the worker receiving a relative high dose, it did not reach the threshold value for producing deterministic effects such as cataracts, erythema, and skin damage

Cellular oncogene expression following exposure of mice to γ-rays

International Nuclear Information System (INIS)

Anderson, A.; Woloschak, G.E.

1991-01-01

We examined the effects of total body exposure of BCF1 mice to γ-rays (300 cGy) in modulating expression of cellular oncogenes in both gut and liver tissues. We selected specific cellular oncogenes (c-fos, c-myc, c-src, and c-H-ras), based on their normal expression in liver and gut tissues from untreated mice. As early as 5 min. following whole body exposure of BCF1 mice to γ-rays we detected induction of mRNA specific for c-src and c-H-ras in both liver and gut tissues. c-fos RNA was slightly decreased in accumulation in gut but was unaffected in liver tissue from irradiated mice relative to untreated controls. c-myc mRNA accumulation was unaffected in all tissues examined. These experiments document that modulation of cellular oncogene expression can occur as an early event in tissues following irradiation and suggest that this modulation may play a role in radiation-induced carcinogenesis

Exposure measurement in the neighboring hospital beds during an x-ray procedure in hospitalization unit

Energy Technology Data Exchange (ETDEWEB)

Goto, Rafael E.; Capeleti, Felipe F.; Cabete, Henrique V., E-mail: rafael.goto@fcmsantacasasp.edu.br, E-mail: felipe.capeleti@fcmsantacasasp.edu.br, E-mail: henrique@gmpbrasil.com.br [Faculdade de Ciencias Medicas da Santa Casa Sao Paulo, SP (Brazil); GMP Consultoria em Radioprotecao e Fisica Medica e Assessoria LTDA, Sao Paulo, SP (Brazil)

2017-11-01

There are lots of discussion about the exposure in hospitalization units in Brazil, especially around labor legislation and economic advantages of unhealthiness. With the attention focused on hospitalized patients, there were measured the exposure in neighboring beds of the patient submitted to an X-ray procedure with a mobile X-ray system that could be used to illustrate the discussion with consistent values. The most common X-ray procedure made in hospitalization units are chests images with techniques between 70 to 120 kV and 5 to 20 mAs. The measurement was made during routine exposure and simulations using a scattering phantom with Radcal AccuPro electrometer and 1800cc ionization chamber in a private hospital and a philanthropic hospital, both in Sao Paulo, Brazil. The ionization chambers are placed at 2 meters distance of the patient exposed of both sides during the routine procedure. During the simulation, a nylon phantom of 20 centimeters thick and 30 x 30 cm² size was placed on the bed, a typical exposure technique was used and the exposure was measured surrounding the phantom at 0.6, 1.0 and 2.0 meters distance for scattered radiation characterization. Initial results showed that the neighboring exposure at about 2 meters distance from the exposed patient bed have low values, even when exposure is integrated during the length of hospital stay. Therefore, the exposure in hospitalization units are very low compared to the exams doses. (author). (author)

Feasibility study of gamma-ray medical radiography

International Nuclear Information System (INIS)

Alyassin, Abdalmajeid M.; Maqsoud, Hamza A.; Mashat, Ahmad M.; Al-Mohr, Al-Sayed; Abdulwajid, Subhan

2013-01-01

This research explores the feasibility of using gamma-ray radiography in medical imaging. We will show that gamma-ray medical radiography has the potential to provide alternative diagnostic medical information to X-ray radiography. Approximately one Ci Am-241 radioactive source which emits mono-energetic 59.5 keV gamma rays was used. Several factors that influence the feasibility of this study were tested. They were the radiation source uniformity, image uniformity, and image quality parameters such as contrast, noise, and spatial resolution. In addition, several gamma-ray and X-ray images were acquired using humanoid phantoms. These images were recorded on computed radiography image receptors and displayed on a standard monitor. Visual assessments of these images were then conducted. The Am-241 radioactive source provided relatively uniform radiation exposure and images. Image noise and image contrast were mainly dependent on the exposure time and source size, whereas spatial resolution was dependent on source size and magnification factor. The gamma-ray humanoid phantom images were of lower quality than the X-ray images mainly due to the low radioactivity used and not enough exposure time. Nevertheless, the gamma-ray images displayed most of the main structures contained in the humanoid phantoms. Higher exposure rates and thus lower exposure times were estimated for different pure Am-241 source sizes that are hypothesized to provide high quality images similar to X-ray images. For instance, a 10 mm source size of pure Am-241 with 7 s exposure time should produce images similar in contrast and noise to X-ray images. This research paves the way for the production and usage of a highly radioactive Am-241 source with the potential to lead to the feasibility of acceptable quality medical gamma-ray radiography. - Highlights: ► Characterized the performance of gamma-ray radiography. ► Displayed medical images of humanoid phantoms using gamma radiography. ► Am-241

Calculation of gamma ray exposure rates from uranium ore bodies

International Nuclear Information System (INIS)

Thomson, J.E.; Wilson, O.J.

1980-02-01

The planning of operations associated with uranium mines often requires that estimates be made of the exposure rates from various ore bodies. A straight-forward method of calculating the exposure rate from an arbitrarily shaped body is presented. Parameters for the calculation are evaluated under the assumption of secular equilibrium of uranium with its daughters and that the uranium is uniformly distributed throughout an average soil mixture. The spectral distribution of the emitted gamma rays and the effect of air attenuation are discussed. Worked examples are given of typical situations encountered in uranium mines

The parameters of X-ray equipment that influence in patient exposure

International Nuclear Information System (INIS)

Peixoto, J.E.

1988-01-01

The main components of the X-rays equipment and the secondary device for radiodiagnosis examination are showed. The influence of all radiographs parameters in human exposure as tension and current are also analysed. (C.G.C.) [pt

Influence of chronic x-ray exposure on adrenal glucocorticoid function and adrenocorticocyte membrane potential

International Nuclear Information System (INIS)

Gorban', Je.M.; Topol'nikova, N.V.

1998-01-01

The peculiarities of adrenal glucocorticoid function and membrane potential (MP) of zona fasciculata adrenocorticocyte (ACC) in rats after chronic x-ray exposure was studied. The changes of adrenal glucocorticoid function caused by chronic x-ray exposure within a relatively small period of irradiation (1.5 months) are obscure and manifest themselves only at physiological load. With the prolongation of the period (8 and 15 months), more considerable inhibition of the adrenal glucocorticoid function and disturbances in the membrane mechanisms of ACC MP level regulation are revealed

Determination of personnel exposures in the lower energy ranges of X-ray by photographic dosimeter

International Nuclear Information System (INIS)

Ha, C.W.; Kim, J.R.; Suk, K.W.

1986-01-01

This paper described an improved technical method required for proper evaluation of personnel exposures by means of the photographic dosimeter developed by KAERI in lower gamma or X-ray energy regions, with which response of the dosimeter varies significantly. With calibration of the dosimeter in the energy range from 30 to 300 keV, the beam spectrum was carefully selected and specified it adequately. The absorber combinations and absorber thickness used to obtain the specified X-ray spectra from a constant potential X-ray machine were determined theoretically and also experimentally. A correlation between the density and exposure for the four separate energies, such as 49 keV eff , 154 keV eff 250 keV eff and 662 keV, is experimentally determined. As a result, it can be directly evaluated the exposure from the measured response of dosimeter. (Author)

Radiation exposure with the NOMAD portable X-ray system.

Science.gov (United States)

Goren, A D; Bonvento, M; Biernacki, J; Colosi, D C

2008-02-01

A new hand-held battery-operated portable X-ray system was tested for possible leakage radiation through the existing heavy metal compounds surrounding the X-ray tube, backscatter radiation through the lead-filled acrylic shield attached at the end of the exit tube and patient exposure. Dose measurements were conducted using a DXTRR phantom and a water phantom. All measurements were recorded using calibrated thermoluminescent dosimetry (TLD), calibrated Unfors Model 583L dosemeter, and a calibrated Radcal MDH model 1015 dosemeter. The settings for all exposure were 60 kVp, 2.3 mA and 0.25 s using Kodak Insight (Class F) film. All backscatter measurements, in front of the shield, behind the shield, at the finger of the operator, the operator's chest, eyes and gonads were significantly below the maximum permissible radiation leakage as per the United States Food and Drug Administration regulations (100 mR h(-1)). Our measurements indicate that the exposure would be well within the occupational maximum permissible dose for an occupationally exposed person. Film dose was consistent with the manufacturer's recommendations. As a result of our measurements, the State of New York Bureau of Environmental Radiation Protection granted us a variance to use the NOMAD on a case-by-case basis. Our data have shown that the NOMAD presents risks that are no greater than with standard dental radiographic units to the patient or operator and the measured doses are well below recommended levels.

Low-exposure tritium radiotoxicity in mammals

International Nuclear Information System (INIS)

Dobson, R.L.

1982-01-01

Studies of tritium radiotoxicity involving chronic 3 H0H exposures in mammals demonstrate in both mice and monkeys that biological effects can be measured following remarkably low levels of exposure - levels in the range of serious practical interest to radiation protection. These studies demonstrate also that deleterious effects of 3 H beta radiation do not differ significantly from those of gamma radiation at high exposures. In contrast, however, at low exposures tritium is significantly more effective than gamma rays, rad for rad, by a factor approaching 3. This is important for hazard evaluation and radiation protection because knowledge concerning biological effects of chronic low-level radiation exposure has come mainly from gamma-ray data; and predictions based on gamma-ray data will underestimate tritium effects - especially at low exposures - unless the RBE is fully taken into account

Acute behavioural dysfunctions following exposure to γ-rays

International Nuclear Information System (INIS)

Kumar, Mayank; Haridas, Seenu; Manda, Kailash

2014-01-01

Exposure to ionizing radiations (IR) has been reported to have many ill effects. These are manifested immediately after exposure and may persist or develop long after the incident. The severity and manifestation is dependent on the absorbed dose and type of the IR. These have been reported extensively in human subjects; especially among the victims of the accidental exposure and radiotherapy patients. Additionally, there have been a plethora of studies in animal models which support these findings, and are being used to test radio-mitigative or radio-protective strategies. The vulnerability of neuronal tissue to IR is well known, however the acute dose-dependent behavioural consequences have yet to be understood. Thus, our laboratory has been trying to decipher the dose-dependent behavioural dysfunctions which have occurred 24-72 hours post IR exposure and possible radio-protective strategies. We are utilizing mouse models of studying the behavioural processes, in a test battery conceptualized to study the affective and cognitive skills as well as motor skills of the animals. Additionally, we have observed cellular damage to different areas of the brain and subsequent correlations to behavioural dysfunctions. This has being carried out by using single cell gel electrophoresis (SCGE) and Diffusion Tensor Imaging (DTI). The findings show that after exposure to sub-lethal γ-rays, there are significant changes that occur in all the behavioural parameters. The most sensitive area has been found to be the Hippocampus as visualized by DTI and the SCGE. Consequently, short term and long term memory functions have been shown to be disrupted within 24-72 hours of exposure. Acute dysfunctions of affective functions have also been demonstrated to materialise within 24 hours post exposure. Unexpectedly, the behavioural dysfunctions were seen to be dose independent. Thus, this study provides a foundation to help decipher the acute behavioural manifestations of IR exposure

Gamma-ray mass attenuation coefficient and half value layer factor of some oxide glass shielding materials

International Nuclear Information System (INIS)

Waly, El-Sayed A.; Fusco, Michael A.; Bourham, Mohamed A.

2016-01-01

The variation in dosimetric parameters such as mass attenuation coefficient, half value layer factor, exposure buildup factor, and the photon mean free path for different oxide glasses for the incident gamma energy range 0.015–15 MeV has been studied using MicroShield code. It has been inferred that the addition of PbO and Bi 2 O 3 improves the gamma ray shielding properties. Thus, the effect of chemical composition on these parameters is investigated in the form of six different glass compositions, which are compared with specialty concrete for nuclear radiation shielding. The composition termed ‘Glass 6’ in this paper has the highest mass attenuation and the smallest half value layer and may have potential applications in radiation shielding. An example dry storage cask utilizing an additional layer of Glass 6 as an intermediate shielding layer, simulated in MicroShield, is capable of reducing the exposure rate at the cask surface by over 20 orders of magnitude compared to the case without a glass layer. Based on this study, Glass 6 shows promise as a gamma-ray shielding material, particularly for dry cask storage.

A novel method of microneedle array fabrication using inclined deep x-ray exposure

International Nuclear Information System (INIS)

Moon, Sang Jun; Jin, Chun Yan; Lee, Seung S

2006-01-01

We report a novel fabrication method for the microneedle array with a 3-dimensional feature and its replication method; 'Hot-pressing' process with bio-compatible material, PLLA (Poly L-LActide). Using inclined deep X-ray exposure technique, we fabricate a band type microneedle array with a single body on the same material basement. Since the single body feature does not make adhesion problem with the microneedle shank and basement during peel-off step of a mold, the PMMA (Poly-Methyl-MethAcrylate) microneedle array mold insert can be used for mold process which is used with the soft material mold, PDMS (Poly-Di- Methyl-Siloxane). The side inclined deep X-ray exposure also makes complex 3-dimensional features by the regions which are not exposed during twice successive exposure steps. In addition, the successive exposure does not need an additional mask alignment after the first side exposure. The fabricated band type microneedle array mold inserts are assembled for large area patch type out-of-plane microneedle array. The bio-compatible microneedle array can be fabricated to the laboratory scale mass production by the single body PMMA mold insert and 'Hot-pressing' process

A novel method of microneedle array fabrication using inclined deep x-ray exposure

Energy Technology Data Exchange (ETDEWEB)

Moon, Sang Jun; Jin, Chun Yan; Lee, Seung S [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-dong, Daejeon (Korea, Republic of)

2006-04-01

We report a novel fabrication method for the microneedle array with a 3-dimensional feature and its replication method; 'Hot-pressing' process with bio-compatible material, PLLA (Poly L-LActide). Using inclined deep X-ray exposure technique, we fabricate a band type microneedle array with a single body on the same material basement. Since the single body feature does not make adhesion problem with the microneedle shank and basement during peel-off step of a mold, the PMMA (Poly-Methyl-MethAcrylate) microneedle array mold insert can be used for mold process which is used with the soft material mold, PDMS (Poly-Di- Methyl-Siloxane). The side inclined deep X-ray exposure also makes complex 3-dimensional features by the regions which are not exposed during twice successive exposure steps. In addition, the successive exposure does not need an additional mask alignment after the first side exposure. The fabricated band type microneedle array mold inserts are assembled for large area patch type out-of-plane microneedle array. The bio-compatible microneedle array can be fabricated to the laboratory scale mass production by the single body PMMA mold insert and 'Hot-pressing' process.

Characteristics of environmental gamma-rays and dose assessment

International Nuclear Information System (INIS)

Saito, Kimiaki; Moriuchi, Shigeru

1986-01-01

Environmental radioactivity has attracted much attention in terms of exposure to the population, although its exposure doses are minimal. This paper presents problems encountered in the assessment of exposure doses using model and monitoring systems, focusing on the characteristics, such as energy distribution, direction distribution, and site, of environmental gamma-rays. The assessment of outdoor and indoor exposure doses of natural gamma-rays is discussed in relation to the shielding effect of the human body. In the assessment of artificial gamma-rays, calculation of exposure doses using build-up factor, the shielding effect of the human body, and energy dependency of the measuring instrument are covered. A continuing elucidation about uncertainties in dose assessment is emphasized. (Namekawa, K.)

Circulating blocking factors of lymphoid-cell cytotoxicity in x-ray-induced rat small-bowel adenocarcinoma

International Nuclear Information System (INIS)

Stevens, R.H.; Brooks, G.P.; Osborne, J.W.

1979-01-01

Circulating blocking factors capable of abrogating cell-mediated immune responses measured by in vitro lymphoid-cell cytotoxicity were identified in the sera of Holtzman outbred rats 6 to 9 months after a single exposure of only the temporarily exteriorized, hypoxic ileum and jejunum to 1700 to 2000 R of X radiation. Such factors were found to exist in the serum of every animal exposed to the ionizing radiation regardless of whether a visibly identifiable small-bowel adenocarcinoma existed or subsequently would develop. Protection of cultured x-ray-induced rat small-bowel cancer cells from destruction by tumor-sensitized lymphoid cells as measured by the release of lactoperoxidase-catalyzed radioiodinated membrane proteins from the tumor target cells was conferred by the action of the blocking factors at both effector and target cell levels. The results of this study demonstrate that exposure of only the rat small intestine to ionizing radiation leads to elaboration of circulating factors identifiable several months postirradiation which will block cell-mediated immune responses directed against cancer cells developing in the exposed tissue

Protocol for X-ray dosimetry and exposure arrangements employed in studies of late somatic effects in mammals

International Nuclear Information System (INIS)

Zoetelief, J.; Kogel, A.J. van der; Broerse, J.J.; Scarpa, G.; Dixon-Brown, A.

1985-01-01

A number of European laboratories studying the late effects of ionizing radiation in animals have established an effective cooperation within the European Late Effects Project Group (EULEP) since 1970. To facilitate the exchange of biological results several techniques, including quality control of the experimental animals, pathology and dosimetry, have to be standardized. The most important aspects of the procedures for X-irradiation and dosimetry of small animals are summarized. These include recommendations on irradiation conditions, dosimetry methods, characteristics of phantoms and factors affecting X-ray dosimetry. X-irradiation procedures employed by the participating institutes are described and the results of five X-ray dosimetry intercomparisons are reported. The introduction of a common dosimetry protocol has resulted in improvements in exposure arrangements and absolute dosimetry. (author)

Comparison of cytogenetic effects after occupational exposure to X-rays with those after foetal pelvimetric exposure

International Nuclear Information System (INIS)

Kirsch-Volders, M.; Poma, K.; Verschaeve, L.; Hens, L.; Susanne, C.; Elegem, P. van

1978-01-01

In utero acute low-level exposure to X-rays (300 to 350 mrads) induces a significant increase of band-loss in G-trypsin banded chromosomes of umbilical lymphocytes. Results, however, have to be confirmed by dose-effect relation studies and analysis with spectro-photometric scanning of deleted chromosomes. The same in utero exposure induces a significant dissociaton of chromosome pair 13 as revealed by centromere-centromere, angle and association tendency analysis of chromosome distribution in comparison with a control group. Occupational chronic low-level exposure to ionizing radiation does not modify significantly the amount of SCE in lymphocytes of peripheral blood. However, an analysis of centromere-centromere distances, angle values and associaton tendencies of the different chromosome combinations clearly shows an association of chromosome pair 12-16 after exposure to ionizing radiation. It is difficult to assess the exact biological importance of the observed chromosome modifications. However, referring to the already described dissociation of human acrocentric chromosomes after in vivo exposure to low levels of phenyl Hg acetate or inorganic Pb, the chromosome distribution seems not to be significantly disturbed by chronic or acute low-level exposure to ionizing radiation. (author)

Standardized approach for developing probabilistic exposure factor distributions

Energy Technology Data Exchange (ETDEWEB)

Maddalena, Randy L.; McKone, Thomas E.; Sohn, Michael D.

2003-03-01

The effectiveness of a probabilistic risk assessment (PRA) depends critically on the quality of input information that is available to the risk assessor and specifically on the probabilistic exposure factor distributions that are developed and used in the exposure and risk models. Deriving probabilistic distributions for model inputs can be time consuming and subjective. The absence of a standard approach for developing these distributions can result in PRAs that are inconsistent and difficult to review by regulatory agencies. We present an approach that reduces subjectivity in the distribution development process without limiting the flexibility needed to prepare relevant PRAs. The approach requires two steps. First, we analyze data pooled at a population scale to (1) identify the most robust demographic variables within the population for a given exposure factor, (2) partition the population data into subsets based on these variables, and (3) construct archetypal distributions for each subpopulation. Second, we sample from these archetypal distributions according to site- or scenario-specific conditions to simulate exposure factor values and use these values to construct the scenario-specific input distribution. It is envisaged that the archetypal distributions from step 1 will be generally applicable so risk assessors will not have to repeatedly collect and analyze raw data for each new assessment. We demonstrate the approach for two commonly used exposure factors--body weight (BW) and exposure duration (ED)--using data for the U.S. population. For these factors we provide a first set of subpopulation based archetypal distributions along with methodology for using these distributions to construct relevant scenario-specific probabilistic exposure factor distributions.

Fabrication of open-top microchannel plate using deep X-ray exposure mask made with silicon on insulator substrate

CERN Document Server

Fujimura, T; Etoh, S I; Hattori, R; Kuroki, Y; Chang, S S

2003-01-01

We propose a high-aspect-ratio open-top microchannel plate structure. This type of microchannel plate has many advantages in electrophoresis. The plate was fabricated by deep X-ray lithography using synchrotron radiation (SR) light and the chemical wet etching process. A deep X-ray exposure mask was fabricated with a silicon on insulator (SOI) substrate. The patterned Si microstructure was micromachined into a thin Si membrane and a thick Au X-ray absorber was embedded in it by electroplating. A plastic material, polymethylmethacrylate (PMMA) was used for the plate substrate. For reduction of the exposure time and high-aspect-ratio fast wet development, the fabrication condition was optimized with respect to not the exposure dose but to the PMMA mean molecular weight (M.W.) changing after deep X-ray exposure as measured by gel permeation chromatography (GPC). Decrement of the PMMA M.W. and increment of the wet developer temperature accelerated the etching rate. Under optimized fabrication conditions, a microc...

Influence of X-ray exposure on morphologic composition of blood of sheep

International Nuclear Information System (INIS)

Tukhtaev, T.M.; Badalov, S.

1983-01-01

Present article is devoted influence of X-ray exposure on morphologic composition of blood of sheep. Thus, pathogenetic mechanisms of formation of acute radiation sickness of laboratory animals are studied. The experiments are described.

The primary exposure standard of ENEA for medium energy X-ray: characteristics and measurements procedures

International Nuclear Information System (INIS)

Laitano, R.F.; Toni, M.P.

1983-01-01

A description is given of a medium energy X-ray free-air chamber used, as primary exposure standard, at the Laboratorio di Metrologia delle Radiazioni Ionizzanti of the Enea in Italy. The main features of an X-ray facility for the production of radiation between 40 KeV and 400 KeV are also described. The measurements procedures are then analyzed with respect to the realization of the exposure unit in the relevant energy range. Finally the results of some international comparisons are reported

Effect of medical x-ray exposure on subsequent reproductive outcomes in scoliosis patients

International Nuclear Information System (INIS)

Visscher, W.A.

1987-01-01

A retrospective cohort study was done which was designed to assess the effects of medical x-ray exposure on cancer incidence among scoliosis patients. Although the primary purpose of the study was to assess cancer incidence, a secondary goal was to investigate whether diagnostic x-ray exposure is related to adverse reproductive events in the female subjects. A series of case-control analyses were done which were designed to assess these effects. Radiation exposure was measured both by total films received and by an estimate of the number of films received and by an estimate of the number of films which involved ovarian irradiation. Radiation appeared to increase a woman's risk of any adverse event in the overall analysis and her risk of a premature or low birth weight infant in the separate analyses. Radiation did not appear to be related to spontaneous abortion, complications of pregnancy or delivery or birth defects, although the results of the pregnancy complications analysis was suggestive

X-ray exposure in utero and school performance: a population-based study of X-ray pelvimetry

International Nuclear Information System (INIS)

Nordenskjöld, A.C.; Palme, M.; Kaijser, M.

2015-01-01

Aim: To investigate the association between exposure to ionising radiation from pelvimetric examinations in utero and school performance. Material and methods: This was a population-based cohort study comprising 46,066 children born in the county of Östergötland, Sweden, from 1980 through 1990. Through record linkage between Swedish registers, children exposed in utero to X-ray pelvimetry examination were compared to other children born in the same county during the study period, as well as to their unexposed siblings. Outcome variable was primary school grades, expressed in centiles and calculated through linear regression. Results: In the univariate analysis, children exposed to X-ray pelvimetry in utero had higher school grades compared to unexposed children (point estimate 3 centiles, 95% confidence interval [CI]: 1.5 to 4.6). When sex, mother's education and income, birth order, and birth position were included in the analysis; however, the difference was reduced and the association was no longer statistically significant (PE 1.4, 95% CI: –0.1 to 2.8). Comparing exposed children with their siblings showed no statistical difference in univariate analysis or in multivariate analysis. Conclusion: No suggestion was found of a negative effect on school performance from in utero exposure of diagnostic X-ray pelvimetry. -- Highlights: •Pelvimetric examinations expose fetus to low levels of radiation. •No detectable effect on childrens final primary school grades from pelvimetric examinations. •Pelvimetric examinations is a safe procedure for the fetus regarding shool performance

Exposure of patients and creation of system of quality assurance in conventional x-ray radiology in Lithuania

International Nuclear Information System (INIS)

Morkunas, G.; Ziliukas, J.

1999-01-01

One of the most important sources of exposure is medical application of ionizing radiation. X-ray examination comprise a significant part of medical exposure. Doses received by patients and quality of diagnostic images are to be optimized. Measurements of these doses were started by the Radiation Protection Centre in 1997. These measurements are performed in randomly selected x-ray departments all around Lithuania during examinations of chest and lumbar spine. Dose and parameters related to exposure and patient are registered. Quality control measurements by PMX-III are being performed on each x-ray machine used for examination. The results show that in many cases the guidance levels are of entrance surface dose for standard patient determined by the Basic Radiation Protection Standard of Lithuania are exceeded. Quality control of x-ray machines performed in 1997-1999 shows that more than 30% of these machines did not comply with the requirements though in many cases shortcomings are minor and easily removed. (au)

X-ray detector for automatic exposure control using ionization chamber filled with xenon gas

CERN Document Server

Nakagawa, A; Yoshida, T

2003-01-01

This report refers to our newly developed X-ray detector for reliable automatic X-ray exposure control, which is to be widely used for X-ray diagnoses in various clinical fields. This new detector utilizes an ionization chamber filled with xenon gas, in contrast to conventional X-ray detectors which use ionization chambers filled with air. Use of xenon gas ensures higher sensitivity and thinner design of the detector. The xenon gas is completely sealed in the chamber, so that the influence of the changes in ambient environments is minimized. (author)

Dental X-ray diagnostic facility with means to choose the time of exposure

Energy Technology Data Exchange (ETDEWEB)

Krause, H; Grassme, U

1978-02-16

Equipment for dental X-ray diagnostics with automatic exposure control. In the patient's mouth there is arranged a film carrier containing in a pocket a dental X-ray film. A detector-transmitter assembly touches the pocket. It reacts to the density of the film and wireless transmits a signal to an antenna. This antenna is connected to a receiver shutting off the high voltage of the X-ray tube by means of a circuit if a desired dose value is reached. The detector-transmitter unit is an integrated component. It has got a luminescent layer with a light-sensitive detector or a detector directly sensitive to X-rays.

75 FR 5317 - Exposure Factors Handbook: 2009 Update

Science.gov (United States)

2010-02-02

... chemicals. These factors include: Drinking water consumption; mouthing behavior; soil ingestion rates... document solely for the purpose of pre- dissemination peer review under applicable information quality... various factors used in assessing human exposure. This Handbook is aimed at exposure assessors inside the...

ABCC-JNIH adult health study Hiroshima and Nagasaki 1961 exposure to medical x-ray. Preliminary survey

Energy Technology Data Exchange (ETDEWEB)

Ishimaru, Toranosuke; Russell, W J

1962-05-16

A survey was conducted for three months among subjects seen in the medical clinics of ABCC, Hiroshima and Nagasaki, to determine the extent of medical x-ray received in ABCC and other hospitals and clinics. Emphasis was chiefly methodological to prepare for later studies designed to evaluate the contribution of medical x-ray to total radiation dose received by survivors of the atomic bombings and controls. The frequency, the institution in which the subject received x-ray, as well as the types of exposure were the prime considerations in the survey. The data were analyzed for each city by sex, age, and exposure status. 2 references, 5 figures, 11 tables.

Noble gases, nitrogen and cosmic ray exposure age of the Sulagiri chondrite

Directory of Open Access Journals (Sweden)

Ramakant R. Mahajan

2017-01-01

Full Text Available The Sulagiri meteorite fell in India on 12 September 2008, LL6 chondrite class is the largest among all the Indian meteorites. Isotopic compositions of noble gases (He, Ne, Ar, Kr and Xe and nitrogen in the Sulagiri meteorite and cosmic ray exposure history are discussed. Low cosmogenic (22Ne/21Nec ratio is consistent with irradiation in a large body. Cosmogenic noble gases indicate that Sulagiri has a 4π cosmic-ray exposure (CRE age of 27.9 ± 3.4 Ma and is a member of the peak of CRE age distribution of LL chondrites. Radiogenic 4He and 40Ar concentrations in Sulagiri yields the radiogenic ages as 2.29 and 4.56 Ga, indicating the loss of He from the meteorite. Xenon and krypton are mixture of Q and spallogenic components.

Noble gases, nitrogen and cosmic ray exposure age of the Sulagiri chondrite

Institute of Scientific and Technical Information of China (English)

Ramakant R. Mahajan

2017-01-01

The Sulagiri meteorite fell in India on 12 September 2008, LL6 chondrite class is the largest among all the Indian meteorites. Isotopic compositions of noble gases (He, Ne, Ar, Kr and Xe) and nitrogen in the Sulagiri meteorite and cosmic ray exposure history are discussed. Low cosmogenic (22Ne/21Ne)c ratio is consistent with irradiation in a large body. Cosmogenic noble gases indicate that Sulagiri has a 4πcosmic-ray exposure (CRE) age of 27.9 ± 3.4 Ma and is a member of the peak of CRE age distribution of LL chondrites. Radiogenic 4He and 40Ar concentrations in Sulagiri yields the radiogenic ages as 2.29 and 4.56 Ga, indicating the loss of He from the meteorite. Xenon and krypton are mixture of Q and spallo-genic components.

Time-activity relationships to VOC personal exposure factors

Science.gov (United States)

Edwards, Rufus D.; Schweizer, Christian; Llacqua, Vito; Lai, Hak Kan; Jantunen, Matti; Bayer-Oglesby, Lucy; Künzli, Nino

Social and demographic factors have been found to play a significant role in differences between time-activity patterns of population subgroups. Since time-activity patterns largely influence personal exposure to compounds as individuals move across microenvironments, exposure subgroups within the population may be defined by factors that influence daily activity patterns. Socio-demographic and environmental factors that define time-activity subgroups also define quantifiable differences in VOC personal exposures to different sources and individual compounds in the Expolis study. Significant differences in exposures to traffic-related compounds ethylbenzene, m- and p-xylene and o-xylene were observed in relation to gender, number of children and living alone. Categorization of exposures further indicated time exposed to traffic at work and time in a car as important determinants. Increased exposures to decane, nonane and undecane were observed for males, housewives and self-employed. Categorization of exposures indicated exposure subgroups related to workshop use and living downtown. Higher exposures to 3-carene and α-pinene commonly found in household cleaning products and fragrances were associated with more children, while exposures to traffic compounds ethylbenzene, m- and p-xylene and o-xylene were reduced with more children. Considerable unexplained variation remained in categorization of exposures associated with home product use and fragrances, due to individual behavior and product choice. More targeted data collection methods in VOC exposure studies for these sources should be used. Living alone was associated with decreased exposures to 2-methyl-1-propanol and 1-butanol, and traffic-related compounds. Identification of these subgroups may help to reduce the large amount of unexplained variation in VOC exposure studies. Further they may help in assessing impacts of urban planning that result in changes in behavior of individuals, resulting in shifts in

An Industrial Radipgraphy Exposure Device Based on Measurement of Transmitted Gamma-Ray Intensity

International Nuclear Information System (INIS)

Polee, C.; Chankow, N.; Srisatit, S.; Thong-Aram, D.

2014-01-01

In film radiography, underexposure and overexposure may happen particularly when lacking knowledge of specimen material and hollowness. This paper describes a method and a device for determining exposure in industrial gamma-ray radiography based on quick measurement of transmitted gamma-ray intensity with a D3372 Hamamatsu small GM tube. Application software is developed for Android mobile phone to remotely control the device and to display the counting data via Bluetooth. Prior to placing film, the device is placed behind the specimen to be radiographed to determine the exposure time from the transmitted intensity which is independent on source activity, source-to-film distance, specimen thickness and kind of material. The developed technique and device make radiographic process economic, convenient and more reliable.

Exposure to power frequency magnetic fields suppresses X-ray-induced apoptosis transiently in Ku80-deficient xrs5 cells

International Nuclear Information System (INIS)

Tian, Furong; Nakahara, Takehisa; Yoshida, Masami; Honda, Naoko; Hirose, Hideki; Miyakoshi, Junji

2002-01-01

In an attempt to determine whether exposure to extremely low frequency (ELF) electromagnetic fields can affect cells, Ku80-deficient cells (xrs5) and Ku80-proficient cells (CHO-K1) were exposed to ELF electromagnetic fields. Cell survival, and the levels of the apoptosis-related genes p21, p53, phospho-p53 (Ser 15 ), caspase-3 and the anti-apoptosis gene bcl-2 were determined in xrs5 and CHO-K1 cells following exposure to ELF electromagnetic fields and X-rays. It was found that exposure of xrs5 and CHO-K1 cells to 60 Hz ELF electromagnetic fields had no effect on cell survival, cell cycle distribution and protein expression. Exposure of xrs5 cells to 60 Hz ELF electromagnetic fields for 5 h after irradiation significantly inhibited G 1 cell cycle arrest induced by X-rays (1 Gy) and resulted in elevated bcl-2 expression. A significant decrease in the induction of p53, phospho-p53, caspase-3 and p21 proteins was observed in xrs5 cells when irradiation by X-rays (8 Gy) was followed by exposure to 5 mT ELF magnetic fields. Exposure of xrs5 cells to the ELF electromagnetic fields for 10 h following irradiation significantly decreased X-ray-induced apoptosis from about 1.7% to 0.7%. However, this effect was not found in CHO-K1 cells within 24 h of irradiation by X-rays alone and by X-rays combined with ELF electromagnetic fields. Exposure of xrs5 cells to 60 Hz ELF electromagnetic fields following irradiation can affect cell cycle distribution and transiently suppress apoptosis by decreasing the levels of caspase-3, p21, p53 and phospho-p53 and by increasing bcl-2 expression

Exposure to psychosocial work factors in 31 European countries.

Science.gov (United States)

Niedhammer, I; Sultan-Taïeb, H; Chastang, J-F; Vermeylen, G; Parent-Thirion, A

2012-04-01

Although psychosocial work factors are recognized as major occupational risk factors, little information is available regarding the prevalence of exposure to these factors and the differences in exposure between countries. To explore the differences in various psychosocial work exposures between 31 European countries. The study was based on a sample of 14,881 male and 14,799 female workers from the 2005 European Working Conditions Survey. Eighteen psychosocial work factors were studied: low decision latitude (skill discretion and decision authority), high psychological demands, job strain, low social support, iso-strain, physical violence, sexual harassment, bullying, discrimination, work-family imbalance, long working hours, high effort, job insecurity, low job promotion, low reward and effort-reward imbalance. Covariates were age, number of workers in household, occupation, economic activity, self-employed/employee, public/private sector and part/full time work. Statistical analysis was performed using multilevel logistic regression analysis. Significant differences in all psychosocial work factors were observed between countries. The rank of the countries varied according to the exposure considered. However, some countries, especially Denmark, Netherlands and Norway, displayed a significantly lower prevalence of exposure to four factors or more, while some Southern and Eastern countries, especially Czech Republic, Greece, Lithuania and Turkey, had a higher prevalence. Differences in psychosocial work exposures were found between countries. This study is the first to compare a large set of psychosocial work exposures between 31 European countries. These findings may be useful to guide prevention policies at European level.

Variability and uncertainty in Swedish exposure factors for use in quantitative exposure assessments.

Science.gov (United States)

Filipsson, Monika; Öberg, Tomas; Bergbäck, Bo

2011-01-01

Information of exposure factors used in quantitative risk assessments has previously been compiled and reported for U.S. and European populations. However, due to the advancement of science and knowledge, these reports are in continuous need of updating with new data. Equally important is the change over time of many exposure factors related to both physiological characteristics and human behavior. Body weight, skin surface, time use, and dietary habits are some of the most obvious examples covered here. A wealth of data is available from literature not primarily gathered for the purpose of risk assessment. Here we review a number of key exposure factors and compare these factors between northern Europe--here represented by Sweden--and the United States. Many previous compilations of exposure factor data focus on interindividual variability and variability between sexes and age groups, while uncertainty is mainly dealt with in a qualitative way. In this article variability is assessed along with uncertainty. As estimates of central tendency and interindividual variability, mean, standard deviation, skewness, kurtosis, and multiple percentiles were calculated, while uncertainty was characterized using 95% confidence intervals for these parameters. The presented statistics are appropriate for use in deterministic analyses using point estimates for each input parameter as well as in probabilistic assessments. © 2010 Society for Risk Analysis.

Alteration of the Carbon and Nitrogen Isotopic Composition in the Martian Surface Rocks Due to Cosmic Ray Exposure

Science.gov (United States)

Pavlov, A. A.; Pavlov, A. K.; Ostryakov, V. M.; Vasilyev, G. I.; Mahaffy, P.; Steele, A.

2014-01-01

C-13/C-12 and N-15/N-14 isotopic ratios are pivotal for our understanding of the Martian carbon cycle, history of the Martian atmospheric escape, and origin of the organic compounds on Mars. Here we demonstrate that the carbon and nitrogen isotopic composition of the surface rocks on Mars can be significantly altered by the continuous exposure of Martian surface to cosmic rays. Cosmic rays can effectively produce C-13 and N-15 isotopes via spallation nuclear reactions on oxygen atoms in various Martian rocks. We calculate that in the top meter of the Martian rocks, the rates of production of both C-13 and N-15 due to galactic cosmic rays (GCRs) exposure can vary within 1.5-6 atoms/cm3/s depending on rocks' depth and chemical composition. We also find that the average solar cosmic rays can produce carbon and nitrogen isotopes at a rate comparable to GCRs in the top 5-10 cm of the Martian rocks. We demonstrate that if the total carbon content in a surface Martian rock is <10 ppm, then the "light," potentially "biological" C-13/C-12 ratio would be effectively erased by cosmic rays over 3.5 billion years of exposure. We found that for the rocks with relatively short exposure ages (e.g., 100 million years), cosmogenic changes in N-15/N-14 ratio are still very significant. We also show that a short exposure to cosmic rays of Allan Hills 84001 while on Mars can explain its high-temperature heavy nitrogen isotopic composition (N-15/N-14). Applications to Martian meteorites and the current Mars Science Laboratory mission are discussed.

Estimation of foetus risk from x-ray pelvimetric examinations

International Nuclear Information System (INIS)

Iba, Shozo; Sato, Kazuichi

1983-01-01

X-ray pelvimetric examinations are carried out for the purpose of diagnosing the cephalo pelvic disproportion at terminal pregnancy and they are still an excellent method, being performed more often than other examinations. However the invitable fetal exposure is considered to be a significant dose and makes an estimation of stochastic fetal risk related to x-ray exposure and to investigate the methods of dose reduction. As the methods judging the exposure dose actually made in the hospitals, a questionnarie regarding the main technical factors of an x-ray examination was given to 26 hospitals, including 5 university hospitals, in Kantou district, and the answeres were analyzed. The estimated risks involving genetics, leukemia and malignant diseases were dependent on the exposure dose which could be calculated on the basis of the technical factors obtained. Total risks on the foetus ranged widely from 1.27 x 10 rad -1 to 1.19 x 10 rad -1 . So for as we have investigated, if all the hospitals used a grid ratio of 5:1, a tube voltage of 120 kV, intensitying screens with rare earth phosphors and green-sensitive orthomatic medical x-ray films for the x-ray pelvimetric examinations, it would be possible to reduce the present exposure dose by one-fourth. The ratio of the x-ray pelvimetry taken on pregnant patients ranged from 2 % to 33 %, having a mean value of 15 %. (author)

Use of lead aprons - further considerations of estimation of doses and conditions of acute exposures of TLD badge in diagnostic x-ray institutions

International Nuclear Information System (INIS)

Pradhan, A.S.; Chatterjee, S.

2003-01-01

In the recent study the authors reported that the exposure conditions of the use of the TLD badge, whether worn under or over the lead apron could be estimated from the readout of the TLD badge used in X-ray diagnostic departments. The effectiveness of lead aprons procured from different suppliers having the same value of quoted nominal lead equivalence was found to vary severely and this indicated some limitation in the applicability of the method of evaluation of exposure conditions of the badge. The transmission factors for the lead aprons varied up to a factor of 15 for the same value of quoted nominal lead equivalence procured from three different suppliers. This is of serious consequences in radiation protection and attracts attention for quality control. An error in the estimation of the exposure conditions of the TLD badge could lead to an underestimation of doses up to 4 times using the prevalent method. The estimation of the actual doses of radiation workers in the cases of over-exposures for the situations of the use of the TLD badge over the lead apron showed that the variation in the quality of lead aprons could be wrong in the range from 1.6 to 25 times even if the kVp of the machine is exactly known. Therefore, attempt should not be made to estimate the actual doses under lead apron from the readout of the TLD badge worn over the apron, as the real values of the transmission factors of the aprons and kVp of the X-ray machine may not be available. (author)

Radiation exposure in X-ray studies of the hips

Energy Technology Data Exchange (ETDEWEB)

Kainberger, F [Krankenhaus der Barmherzigen Brueder, Salzburg (Austria). Roentgeninstitut

1979-12-01

The genetic exposure of the small child is above all a consequence of the rapid increase in X-ray studies, a problem which has not yet been settled. Through phantom measurements it can be shown, that dose reduction is of considerable practical significance if appropriate lead shielding is employed. The radiation dose can be significantly reduced, provided that the shielding material is of an appropriate lead equivalent. The form of the pelvic shield which is used is also of crucial importance.

The application of synchrotron radiation to X-ray lithography

International Nuclear Information System (INIS)

Spiller, E.; Eastman, D.E.; Feder, R.; Grobman, W.D.; Gudat, W.; Topalian, J.

1976-06-01

Synchrotron radiation from the German electron synchrotron DESY in Hamburg has been used for X-ray lithograpgy. Replications of different master patterns (for magnetic bubble devices, fresnel zone plates, etc.) were made using various wavelengths and exposures. High quality lines down to 500 A wide have been reproduced using very soft X-rays. The sensitivities of X-ray resists have been evaluated over a wide range of exposures. Various critical factors (heating, radiation damage, etc.) involved with X-ray lithography using synchrotron radiation have been studied. General considerations of storage ring sources designed as radiation sources for X-ray lithography are discussed, together with a comparison with X-ray tube sources. The general conclusion is that X-ray lithography using synchrotron radiation offers considerable promise as a process for forming high quality sub-micron images with exposure times as short as a few seconds. (orig.) [de

A practical exposure-equivalent metric for instrumentation noise in x-ray imaging systems

International Nuclear Information System (INIS)

Yadava, G K; Kuhls-Gilcrist, A T; Rudin, S; Patel, V K; Hoffmann, K R; Bednarek, D R

2008-01-01

The performance of high-sensitivity x-ray imagers may be limited by additive instrumentation noise rather than by quantum noise when operated at the low exposure rates used in fluoroscopic procedures. The equipment-invasive instrumentation noise measures (in terms of electrons) are generally difficult to make and are potentially not as helpful in clinical practice as would be a direct radiological representation of such noise that may be determined in the field. In this work, we define a clinically relevant representation for instrumentation noise in terms of noise-equivalent detector entrance exposure, termed the instrumentation noise-equivalent exposure (INEE), which can be determined through experimental measurements of noise-variance or signal-to-noise ratio (SNR). The INEE was measured for various detectors, thus demonstrating its usefulness in terms of providing information about the effective operating range of the various detectors. A simulation study is presented to demonstrate the robustness of this metric against post-processing, and its dependence on inherent detector blur. These studies suggest that the INEE may be a practical gauge to determine and compare the range of quantum-limited performance for clinical x-ray detectors of different design, with the implication that detector performance at exposures below the INEE will be instrumentation-noise limited rather than quantum-noise limited

Micronucleus induction by repeated exposure of diagnostic X-ray on oral buccal mucosa

International Nuclear Information System (INIS)

Lohith Tejashvi, K.; Suchetha Kumari, N.; Shetty, Shishir Ram

2012-01-01

Radiography is the important diagnostic tools essential for diagnosis and planning of orthodontic treatment. X-ray is ionizing radiation which showed various effects include breaking the bond of biological molecules, inducing loss of ability of cell death, increases nuclear alterations. Micronuclei - x000D - (MN) are small chromatin bodies that appear in the cytoplasm by the - x000D - condensation of acrocentric chromosomal fragments or by whole chromosomes. This - x000D - is a sensitive indicator of genetic damage. - x000D - x000D - . To evaluate micronucleus induction by repeated exposure of diagnostic X-ray on human buccal cell. Methods: 25 patients who visiting to ABSMIDS, Department of Oral medicine and Radiology for dental checkup exposed to diagnostic X-ray more than 4 times have been selected for this study. The buccal cell for analysis was collected from the cheek mucosa by means of gentle scraping of epithelial using ice-cream sticks and placed in Buffer saline. This sample was smeared on glass slide and then fixed in methanol:glacial acetic acid (3:1). Air dried and stained with Giemsa for 15-25 minutes. Then 250 cells in each slides were analyzed under microscope and frequency of micronucleus was scored (n=4). Repeated X-ray exposed cells showed micronucleus (1.25%) and nuclear alteration (2.3%) compare to the control. Repeated X-ray exposure leads to induces detectable number of micronucleus and nuclear alterations. (author)

Exposure doses of the patient and the medical staff during urological X-ray examens

International Nuclear Information System (INIS)

Vogel, H.; Loehr, H.; Haug, P.; Schuett, B.

1977-01-01

During 32 intravenous urografies and 48 angiografies of the kidney and the suprarenal glands the X-ray doses at the patient's skin and gonades were determined. During the angiografies the doses were mesured at the hands. the gonades and the front (eyes) of the medical staff. The results are discussed. Because the X-ray doses are relatively high, the number of the pictures and the exposure time is to be reduced to the minimum. Clinical experience and special knowledge is the best X-ray protection. (orig.) [de

Differences in responses to X-ray exposure between osteoclast and osteoblast cells

International Nuclear Information System (INIS)

Zhang, Jian; Wang, Ziyang; Wu, Anqing; Nie, Jing; Pei, Hailong; Hu, Wentao; Wang, Bing; Shang, Peng; Li, Bingyan; Zhou, Guangming

2017-01-01

Radiation-induced bone loss is a potential health concern for cancer patients undergoing radiotherapy. Enhanced bone resorption by osteoclasts and decreased bone formation by osteoblasts were thought to be the main reasons. In this study, we showed that both pre-differentiating and differentiating osteoclasts were relatively sensitive to X-rays compared with osteoblasts. X-rays decreased cell viability to a greater degree in RAW264.7 cells and in differentiating cells than than in osteoblastic MC3T3-E1 cells. X-rays at up to 8 Gy had little effects on osteoblast mineralization. In contrast, X-rays at 1 Gy induced enhanced osteoclastogenesis by enhanced cell fusion, but had no effects on bone resorption. A higher dose of X-rays at 8 Gy, however, had an inhibitory effect on bone resorption. In addition, actin ring formation was disrupted by 8 Gy of X-rays and reorganized into clusters. An increased activity of Caspase 3 was found after X-ray exposure. Actin disorganization and increased apoptosis may be the potential effects of X-rays at high doses, by inhibiting osteoclast differentiation. Taken together, our data indicate high radiosensitivity of osteoclasts. X-ray irradiation at relatively low doses can activate osteoclastogenesis, but not osteogenic differentiation. The radiosensitive osteoclasts are the potentially responsive cells for X-ray-induced bone loss.

Patient-based radiographic exposure factor selection: a systematic review

Energy Technology Data Exchange (ETDEWEB)

Ching, William; Robinson, John; McEntee, Mark, E-mail: mark.mcentee@sydney.edu.au [Discipline of Medical Radiation Sciences, University of Sydney, Lidcombe, New South Wales (Australia)

2014-09-15

Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems. Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose. The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs. Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system.

Patient-based radiographic exposure factor selection: a systematic review

International Nuclear Information System (INIS)

Ching, William; Robinson, John; McEntee, Mark

2014-01-01

Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems. Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose. The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs. Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system

Psychosocial Factors at Work and Blood-Borne Exposure among Nurses

Directory of Open Access Journals (Sweden)

R Mehrdad

2014-01-01

Full Text Available Background: Exposure to human blood and body fluids is a common risk for nurses. Many factors can affect the prevalence and incidence of this occupational hazard. Psychosocial factors at work may be a risk factor for the exposure. Objective: To assess needle stick, sharp injury and mucus exposure to blood-borne pathogens among nurses in Iran and to determine the association between these exposures and psychosocial factors at work. Methods: A cross-sectional study was conducted on nurses in a public hospital, Tehran, Iran. 364 nurses received and 339 completed and returned a self-reported questionnaire containing demographic data, history of exposure to blood-borne pathogens at work during previous year and the General Nordic questionnaire for psychological and social factors at work (QPS Nordic 34+ Questionnaire. Results: Of 339 participants, 197 (58.1% reported needle-stick injury, 186 (54.6% reported another type of sharp injury, and 112 (33% reported a mucous membrane exposure during the previous year. More than half of the participants who had history of exposure, had not reported it. Those with middle or high level of stress had higher crude and adjusted odds than those with lower stress for all kinds of exposure. Adjusted odds ratios for high stress group (ranging from 2.8 to 4.4 were statistically different from 1. Conclusion: There is a high prevalence of needle-stick and sharp injury and mucous membrane exposure to patients' blood or body fluids among studied nurses. There is a significant association between increasing psychosocial factors at work and exposure to blood-borne pathogens among this group of nurses.

Relative merits and limiting factors for x-ray and electron microscopy of thick, hydrated organic materials.

Science.gov (United States)

Du, Ming; Jacobsen, Chris

2018-01-01

Electron and x-ray microscopes allow one to image the entire, unlabeled structure of hydrated materials at a resolution well beyond what visible light microscopes can achieve. However, both approaches involve ionizing radiation, so that radiation damage must be considered as one of the limits to imaging. Drawing upon earlier work, we describe here a unified approach to estimating the image contrast (and thus the required exposure and corresponding radiation dose) in both x-ray and electron microscopy. This approach accounts for factors such as plural and inelastic scattering, and (in electron microscopy) the use of energy filters to obtain so-called "zero loss" images. As expected, it shows that electron microscopy offers lower dose for specimens thinner than about 1 µm (such as for studies of macromolecules, viruses, bacteria and archaebacteria, and thin sectioned material), while x-ray microscopy offers superior characteristics for imaging thicker specimen such as whole eukaryotic cells, thick-sectioned tissues, and organs. The required radiation dose scales strongly as a function of the desired spatial resolution, allowing one to understand the limits of live and frozen hydrated specimen imaging. Finally, we consider the factors limiting x-ray microscopy of thicker materials, suggesting that specimens as thick as a whole mouse brain can be imaged with x-ray microscopes without significant image degradation should appropriate image reconstruction methods be identified. Copyright © 2017 Elsevier B.V. All rights reserved.

Occupational exposure of medical staff due to diagnostic X-ray examinations in veterinary medicine

International Nuclear Information System (INIS)

Mergel, E.; Feige, S.; Haeusler, U.

2007-01-01

The implementation of the Council directive 96/29 EURATOM and the corresponding national Radiation Protection Ordinance and the X-ray Protection Ordinance coming subsequently into effect led to a changed situation regarding the occupational radiation protection in the medical sector. To reduce the occupational exposure of veterinarians and assisting staff in veterinary radiography is particularly challenging as, in opposite to human radiological examination, the presence of staff is indispensable to restrain the patient. Beyond that the relevant literature reports about too high and/or about unnecessary radiation exposures. To gain a comprehensive knowledge upon the possible exposure of involved staff, the variety of typical examination methods in veterinary clinics and at practitioners had been investigated during the daily routine. Dose measurements were performed for different employees during the examinations taking into account several places of exposure (lens, thyroid, chest, hand, gonad, and feet). Veterinary X-ray diagnostic examinations for pets as well as in equine radiography had been accounted for this study. In total, 101 examination methods, 4.484 accompanied examinations and 53.892 single dose readings resulted in a reliable statistical base to set up a 'Job-Exposure-Matrix' allowing the dose assessment for a variable number and kind of examinations. The 'Job-Exposure-Matrix' is believed to be a useful tool for optimization of occupational radiation exposure of veterinarians by appraising the height of a possible dose, forcing a review of the status quo and triggering the improvement of personal protection by establishing adequate measures. (orig.)

Occupational exposure of medical staff due to diagnostic X-ray examinations in veterinary medicine

Energy Technology Data Exchange (ETDEWEB)

Mergel, E.; Feige, S. [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS) (Germany); Haeusler, U. [Bundesamt fuer Strahlenschutz (BfS), Salzgitter (Germany)

2007-07-01

The implementation of the Council directive 96/29 EURATOM and the corresponding national Radiation Protection Ordinance and the X-ray Protection Ordinance coming subsequently into effect led to a changed situation regarding the occupational radiation protection in the medical sector. To reduce the occupational exposure of veterinarians and assisting staff in veterinary radiography is particularly challenging as, in opposite to human radiological examination, the presence of staff is indispensable to restrain the patient. Beyond that the relevant literature reports about too high and/or about unnecessary radiation exposures. To gain a comprehensive knowledge upon the possible exposure of involved staff, the variety of typical examination methods in veterinary clinics and at practitioners had been investigated during the daily routine. Dose measurements were performed for different employees during the examinations taking into account several places of exposure (lens, thyroid, chest, hand, gonad, and feet). Veterinary X-ray diagnostic examinations for pets as well as in equine radiography had been accounted for this study. In total, 101 examination methods, 4.484 accompanied examinations and 53.892 single dose readings resulted in a reliable statistical base to set up a 'Job-Exposure-Matrix' allowing the dose assessment for a variable number and kind of examinations. The 'Job-Exposure-Matrix' is believed to be a useful tool for optimization of occupational radiation exposure of veterinarians by appraising the height of a possible dose, forcing a review of the status quo and triggering the improvement of personal protection by establishing adequate measures. (orig.)

Device for measuring the exposure time in dental X-ray - Cronox

International Nuclear Information System (INIS)

Menezes, Claudio J.M.; Santos, Luiz A.P. dos

2009-01-01

The Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE) developed a test device for monitoring the X-ray beam in dental equipment to its application in quality control programs. This device, called Odontologic Dosimetric Card (CDO of Cartao Dosimetrico Odontologico in Portuguese) uses thermoluminescent dosimeters (TLD) for the measurement of some parameters of the X-ray beam as the entrance surface dose, the peak tension and half value layer (HVL). Radiographic films record the size of the radiation field. However, the TLD does not allow the assessment of exposure time, a parameter that complements the requirements of the Diretrizes de Protecao Radiologica em Radiodiagnostico Medico e Odontologico of Department of Health in Brazil for such equipment. Thus was developed a system based on sensitivity to ionizing radiation of phototransistors for measurement of exposure time when a patient is put in a clinical dental radiography. The system, called CRONOX was sized to be inserted within the CDO. The results showed that the measuring error had developed for less than 3% when compared to reference values obtained with the Tektronix digital oscilloscope, TDS2022 model. The readings obtained with the CRONOX were also compared with the nominal values selected in the X-ray equipment and with the values measured with the instrument of trade PTW Diavolt Universal. The results showed that the measuring device developed showed a maximum deviation of 5.92% on the nominal value selected, while for the instrument of PTW was 17.86%. (author)

Molecular form factors in X-ray crystallography

NARCIS (Netherlands)

Groenewegen, P.P.M.; Feil, D.

1969-01-01

The calculation of molecular form factors from ab initio molecular electronic wavefunctions is discussed, and a scheme for application to X-ray diffraction structure analysis is given. The method is used to calculate the form factor of the NH+4 molecular ion from three accurate molecular

[Effective Techniques to Reduce Radiation Exposure to Medical Staff during Assist of X-ray Computed Tomography Examination].

Science.gov (United States)

Miyajima, Ryuichi; Fujibuchi, Toshioh; Miyachi, Yusuke; Tateishi, Satoshi; Uno, Yoshinori; Amakawa, Kazutoshi; Ohura, Hiroki; Orita, Shinichi

2018-01-01

Medical staffs like radiological technologists, doctors, and nurses are at an increased risk of exposure to radiation while assisting the patient in a position or monitor contrast medium injection during computed tomography (CT). However, methods to protect medical staff from radiation exposure and protocols for using radiological protection equipment have not been standardized and differ among hospitals. In this study, the distribution of scattered X-rays in a CT room was measured by placing electronic personal dosimeters in locations where medical staff stands beside the CT scanner gantry while assisting the patient and the exposure dose was measured. Moreover, we evaluated non-uniform exposure and revealed effective techniques to reduce the exposure dose to medical staff during CT. The dose of the scattered X-rays was the lowest at the gantry and at the examination table during both head and abdominal CT. The dose was the highest at the trunk of the upper body of the operator corresponding to a height of 130 cm during head CT and at the head corresponding to a height of 150 cm during abdominal CT. The maximum dose to the crystalline lens was approximately 600 μSv during head CT. We found that the use of volumetric CT scanning and X-ray protective goggles, and face direction toward the gantry reduced the exposure dose, particularly to the crystalline lens, for which lower equivalent dose during CT scan has been recently recommended in the International Commission on Radiological Protection Publication 118.

Radiation exposure of holding personnel involved in veterinary X-ray diagnosis

International Nuclear Information System (INIS)

Rothe, W.

1977-01-01

An account is given of radiation protection in the context of X-ray examination of small and big animals on the premises of seven reviewed veterinary centres. Also reported are the dosimetric results obtained from holding personnel involved in X-ray diagnosis of 319 big and 4,047 small animals. Infringement of valid regulations was quite often observed, in that animals are held in position in an inadequate way and by unauthorised persons. The measured results, however, have shown that the radiation exposure of vocationally exposed persons can be kept far below the maximum permissible equivalent doses, provided that all applicable rules of radiation protection are observed by those on duty. (author)

DNA Topoisomerase-I Inhibition due to Exposure to X-Rays

International Nuclear Information System (INIS)

Daudee, R.; Gonen, R.; German, U.; Orion, I.; Priel, E.

2014-01-01

In events such as radiological terrorism, accidents involving radioactive materials and occupational exposures, there is a great need to identify exposures to relatively low radiation levels. In many situations, the evaluation of radiation doses is not possible using physical dosimeters as they are not worn, and it is desirable to achieve this based on sensitive biomarkers (1, 2, 3). DNA Topoisomerase-I (Topo-I) is an essential nuclear enzyme that is responsible for the topological state of the DNA. The enzyme is involved in a variety of DNA transactions, including replication, transcription, recombination and DNA repair (4,5). The aim of the present work was to investigate the influence of X-ray radiation on the catalytic activity of this enzyme, and to evaluate its applicability as a biological dosimeter

Image analysis in x-ray cinefluorography

Energy Technology Data Exchange (ETDEWEB)

Ikuse, J; Yasuhara, H; Sugimoto, H [Toshiba Corp., Kawasaki, Kanagawa (Japan)

1979-02-01

For the cinefluorographic image in the cardiovascular diagnostic system, the image quality is evaluated by means of MTF (Modulation Transfer Function), and object contrast by introducing the concept of x-ray spectrum analysis. On the basis of these results, further investigation is made of optimum X-ray exposure factors set for cinefluorography and the cardiovascular diagnostic system.

Skull x-ray

Science.gov (United States)

X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

Hospital and clinic survey estimates of medical x-ray exposures in Hiroshima and Nagasaki, (1)

International Nuclear Information System (INIS)

Sawada, Shozo; Land, C.E.; Otake, Masanori; Russell, W.J.; Takeshita, Kenji.

1980-11-01

All large hospitals and 40% of the small hospitals and clinics in Hiroshima and Nagasaki cities were surveyed for the X-ray examinations they performed during a 2-week period in 1974. The frequency and type of X-ray examinations received by members of the RERF Adult Health Study (AHS) and the RERF Life Span Study (LSS) extended, excluding AHS (Non-AHS), were compared with the general population in each city. Radiologic exposures of patients at hospitals and clinics were most frequent among the general populations. The number of patients, examinations, and exposures per caput per year in each population were estimated. Since the age distribution differed among the three populations, comparisons were made only after correcting for age. On a per caput per year basis exposure frequency was relatively high in the AHS and low in the general populations, a reflection of the greater number of patients in the AHS than in the general populations. Non-AHS males in Nagasaki had a higher X-ray examination rate than did the AHS subjects. The others in the Non-AHS did not differ appreciably from the general populations. There was no difference among these groups according to body sites examined. (author)

Child-Specific Exposure Factors Handbook (2008, Final Report)

Science.gov (United States)

The National Center for Environmental Assessment Staff (NCEA) have prepared this handbook to provide information on various physiological and behavioral factors commonly used in assessing children’s exposure to environmental chemicals. Children have different exposure circumstanc...

A synchrotron-based X-ray exposure station for radiation biology experiments

International Nuclear Information System (INIS)

Thompson, A.C.; Blakely, E.A.; Bjornstad, K.A.; Chang, P.Y.; Rosen, C.J.; Schwarz, R.I.

2007-01-01

Synchrotron X-ray sources enable radiation biology experiments that are difficult with conventional sources. A synchrotron source can easily deliver a monochromatic, tunable energy, highly collimated X-ray beam of well-calibrated intensity. An exposure station at beamline 10.3.1 of the Advanced Light Source (ALS) has been developed which delivers a variable energy (5-20 keV) X-ray fan beam with very sharp edges (10-90% in less than 3 μm). A series of experiments have been done with a four-well slide where a stripe (100 μm widex18 mm long) of cells in each well has been irradiated and the dose varied from well to well. With this facility we have begun a series of experiments to study cells adjacent to irradiated cells and how they respond to the damage of their neighbors. Initial results have demonstrated the advantages of using synchrotron radiation for these experiments

A synchrotron-based X-ray exposure station for radiation biology experiments

Energy Technology Data Exchange (ETDEWEB)

Thompson, A.C. [Division of Life Sciences, Lawrence Berkeley National Laboratory, Bld. 50A-6120, Berkeley, CA 94720 (United States)], E-mail: acthompson@lbl.gov; Blakely, E.A.; Bjornstad, K.A. [Division of Life Sciences, Lawrence Berkeley National Laboratory, Bld. 50A-6120, Berkeley, CA 94720 (United States); Chang, P.Y. [Division of Life Sciences, Lawrence Berkeley National Laboratory, Bld. 50A-6120, Berkeley, CA 94720 (United States); SRI International, Menlo Park, CA (United States); Rosen, C.J.; Schwarz, R.I. [Division of Life Sciences, Lawrence Berkeley National Laboratory, Bld. 50A-6120, Berkeley, CA 94720 (United States)

2007-11-11

Synchrotron X-ray sources enable radiation biology experiments that are difficult with conventional sources. A synchrotron source can easily deliver a monochromatic, tunable energy, highly collimated X-ray beam of well-calibrated intensity. An exposure station at beamline 10.3.1 of the Advanced Light Source (ALS) has been developed which delivers a variable energy (5-20 keV) X-ray fan beam with very sharp edges (10-90% in less than 3 {mu}m). A series of experiments have been done with a four-well slide where a stripe (100 {mu}m widex18 mm long) of cells in each well has been irradiated and the dose varied from well to well. With this facility we have begun a series of experiments to study cells adjacent to irradiated cells and how they respond to the damage of their neighbors. Initial results have demonstrated the advantages of using synchrotron radiation for these experiments.

Effects of pre-natal X-ray exposure on learning behaviour of mice

International Nuclear Information System (INIS)

Frank, P.; Faber, U.; Budny, T.

1983-01-01

The authors investigated whether prenatal X-raying affects the learning behaviour of mice. For this purpose they irradiated mice of strain C57BL/6Ffm with 130 r at different points of the fetal phase. Unirradiated mice served as controls. The animals underwent two learning test series of 14 days each teaching them optical signs. The results of the test series show a distinctly inferior learning ability in the animals exposed to pre-natal irradiation as compared to unirradiated controls. The extent of the reduction of the learning ability depends on the stage of the pregnancy at the time of X-ray exposure. The greatest difference as compared to non-irradiated mice occurred in the animals irradiated at the earliest stage (13th/14th day of pregnancy). The results of the other test groups (15th/16th and 17th/18th day of pregnancy) exhibited less distinct, but still significant differences to the controls. Exposure at the latest period (17th/18th day) coincided with the smallest difference. (orig./MG) [de

Technical study on reduction of patient exposure in x-ray examination

International Nuclear Information System (INIS)

Ohtsuka, Akiyoshi

1983-01-01

This paper deals with the necessity, problems and technical factors on the reduction of the patient exposure, as well as the source of disagreement between doctors and radiologic technologists with respect to their psychological evaluation of the radiological image quality. (1) The patient exposure has a close relationship to the radiological image quality and is affected by many physical and psychological factors. (2) From the patient's point of view, reduction of the patient exposure without the decrease of the image quality has the same meaning as improving the image quality without the increase of the patient exposure. (3) It is known that, in the observation of the radiological image, the radiologic technologists basically attach more importance to the physical evaluation while doctors attach more importance to the psychological evaluation. (4) If doctors and radiologic technologists have more knowledge concerning the radiological imaging technology, optimization of radiographic technique, reduction of the patient exposure and improvement of the diagnostic accuracy can be expected. (author)

High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

Science.gov (United States)

Larsson, Daniel H.; Vågberg, William; Yaroshenko, Andre; Yildirim, Ali Önder; Hertz, Hans M.

2016-12-01

X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. The tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema.

Energy absorption and exposure build-up factors in teeth

International Nuclear Information System (INIS)

Manjunatha, H.C.; Rudraswamy, B.

2010-01-01

Full text: Gamma and X-radiation are widely used in medical imaging and radiation therapy. The user of radioisotopes must have knowledge about how radiation interacts with matter, especially with the human body, because when photons enter the medium/body, they degrade their energy and build up in the medium, giving rise to secondary radiation which can be estimated by a factor which is called the 'build-up factor'. It is essential to study the exposure build up factor in radiation dosimetry. G.P. fitting method has been used to compute energy absorption and exposure build-up factor of teeth (enamel outer surface (EOS), enamel middle (EM), enamel dentin junction towards enamel (EDJE), enamel dentin junction towards dentin (EDJD), dentin middle (DM) and dentin inner surface (DIS)) for wide energy range (0.015 MeV-15 MeV) up to the penetration depth of 40 mean free path. The dependence of energy absorption and exposure build up factor on incident photon energy, Penetration depth and effective atomic number has also been assessed. The relative dose distribution at a distance r from the point source is also estimated. The computed exposure and absorption build-up factors are useful to estimate the gamma and Bremsstrahlung radiation dose distribution teeth which is useful in clinical dosimetry

Food Ingestion Factors of the Korean Exposure Factors Handbook

Directory of Open Access Journals (Sweden)

Jae-Yeon Jang

2014-01-01

Full Text Available The purpose of this study was to establish food ingestion factors needed to assess exposure to contaminants through food ingestion. The study reclassified the raw data of the Korean National Health and Nutrition Examination Survey in 2001 into 12 subcategories including grain products, meat products, fish and shellfish, and vegetables for international comparability of exposure evaluation. The criteria for food intake calculation were unified according to the characteristics of food groups, and recommended values for food ingestion factors were calculated through moisture correction and recategorization of cooked, processed, and mixed foods for each group. The average intake rate for grain and grain products was 6.25 g/kg-d per capita and the men's intake rate was approximately 8% higher than that of the women. The average intake rate of meat and meat products was 1.62 g/kg-d per capita and the men's intake rate was 30% higher than that of the women, on average. The average intake rate of fish and shellfish was 1.53 g/kg-d per capita, and the age groups of 1 to 2 and 3 to 6 recorded higher capita intake rates than other age groups, 2.62 g/kg-d and 2.25 g/kg-d, respectively. The average intake rate of vegetables was 6.47 g/kg-d per capita, with the age group of 1 to 2 recording the highest per capita intake rate of 9.79 g/kg-d and that of 13 to 19 recording the lowest mean. The study also offers recommended values for food ingestion factors of other food groups by gender, age, and region. The food ingestion exposure factors will need future updates in consideration of ongoing changes in food consumption behavior.

Food ingestion factors of the Korean exposure factors handbook.

Science.gov (United States)

Jang, Jae-Yeon; Jo, Soo-Nam; Kim, Sun-Ja; Myung, Hyung-Nam; Kim, Cho-Il

2014-01-01

The purpose of this study was to establish food ingestion factors needed to assess exposure to contaminants through food ingestion. The study reclassified the raw data of the Korean National Health and Nutrition Examination Survey in 2001 into 12 subcategories including grain products, meat products, fish and shellfish, and vegetables for international comparability of exposure evaluation. The criteria for food intake calculation were unified according to the characteristics of food groups, and recommended values for food ingestion factors were calculated through moisture correction and recategorization of cooked, processed, and mixed foods for each group. The average intake rate for grain and grain products was 6.25 g/kg-d per capita and the men's intake rate was approximately 8% higher than that of the women. The average intake rate of meat and meat products was 1.62 g/kg-d per capita and the men's intake rate was 30% higher than that of the women, on average. The average intake rate of fish and shellfish was 1.53 g/kg-d per capita, and the age groups of 1 to 2 and 3 to 6 recorded higher capita intake rates than other age groups, 2.62 g/kg-d and 2.25 g/kg-d, respectively. The average intake rate of vegetables was 6.47 g/kg-d per capita, with the age group of 1 to 2 recording the highest per capita intake rate of 9.79 g/kg-d and that of 13 to 19 recording the lowest mean. The study also offers recommended values for food ingestion factors of other food groups by gender, age, and region. The food ingestion exposure factors will need future updates in consideration of ongoing changes in food consumption behavior.

The rate of X-ray-induced DNA double-strand break repair in the embryonic mouse brain is unaffected by exposure to 50 Hz magnetic fields.

Science.gov (United States)

Woodbine, Lisa; Haines, Jackie; Coster, Margaret; Barazzuol, Lara; Ainsbury, Elizabeth; Sienkiewicz, Zenon; Jeggo, Penny

2015-06-01

Following in utero exposure to low dose radiation (10-200 mGy), we recently observed a linear induction of DNA double-strand breaks (DSB) and activation of apoptosis in the embryonic neuronal stem/progenitor cell compartment. No significant induction of DSB or apoptosis was observed following exposure to magnetic fields (MF). In the present study, we exploited this in vivo system to examine whether exposure to MF before and after exposure to 100 mGy X-rays impacts upon DSB repair rates. 53BP1 foci were quantified following combined exposure to radiation and MF in the embryonic neuronal stem/progenitor cell compartment. Embryos were exposed in utero to 50 Hz MF at 300 μT for 3 h before and up to 9 h after exposure to 100 mGy X-rays. Controls included embryos exposed to MF or X-rays alone plus sham exposures. Exposure to MF before and after 100 mGy X-rays did not impact upon the rate of DSB repair in the embryonic neuronal stem cell compartment compared to repair rates following radiation exposure alone. We conclude that in this sensitive system MF do not exert any significant level of DNA damage and do not impede the repair of X-ray induced damage.

Exposure assessment of neonates in israel to x-ray radiation during hospitalization at neonatal intensive care unit

International Nuclear Information System (INIS)

Datz, H.

2005-03-01

Nowadays nearly 10% of all births in western countries are premature. In the last decade, there has been an increase of 45% in the number of neonates that were born in Israel. At the same time, the survival of neonates, especially those with very low birth weight, VLBW, (less than 1,500 gr), has increased dramatically. Diagnostic radiology plays an important role in the assessment and treatment of neonates requiring intensive care. During their prolonged and complex hospitalization, these infants are exposed to multiple radiographic examinations involving X-ray radiation. The extent of the examinations that the infant undergoes depends on its birth weight, gestational age and its medical problems, where most of the treatment effort is focused especially on VLBW neonates. Most of the diagnostic X-ray examinations taken during the hospitalization of neonates in the neonatal intensive care unit (NICU) consist of imaging of the respiratory and gastrointestinal systems, namely, the chest and abdomen. The imaging process is done using mobile X-ray units located at the NICUs. Due to their long hospitalization periods and complex medical condition, all neonates, and neonates with VLBW in particular, are exposed to a much higher level of diagnostic radiation, compared to normal newborns. The goal of this research was to assess the extent of the exposure of neonates in Israel to X-ray radiation during their hospitalization at the neonatal intensive care unit. Five NICUs, located at different geographical zones in Israel and treating 20% of all newborns in Israel every year, participated in this research. The research was conducted in three phases: Phase I: Collection of information on radiographic techniques and exposure parameters (e.g. kV, mAs, focus to skin distance (FSD), examination borders). 499 X-ray examinations (from 157 neonates) were evaluated for necessary and unnecessary exposure of the neonate's organs to X-ray radiation during these examinations. Phase II

Radiation exposure and image quality in x-Ray diagnostic radiology physical principles and clinical applications

CERN Document Server

Aichinger, Horst; Joite-Barfuß, Sigrid; Säbel, Manfred

2012-01-01

The largest contribution to radiation exposure to the population as a whole arises from diagnostic X-rays. Protecting the patient from radiation is a major aim of modern health policy, and an understanding of the relationship between radiation dose and image quality is of pivotal importance in optimising medical diagnostic radiology. In this volume the data provided for exploring these concerns are partly based on X-ray spectra, measured on diagnostic X-ray tube assemblies, and are supplemented by the results of measurements on phantoms and simulation calculations.

The study on clinical conditions and skin dose of upper-gastrointestinal x-ray fluoroscopy

International Nuclear Information System (INIS)

Kim, Sung Chul; Ahn, Sung Min; Jang, Sang Sup

2007-01-01

This study examined present conditions of upper-gastrointestinal X-ray fluoroscopy and patient skin dose. The authors elected 21 equipment to check the X-ray equipment and exposure factor of fluoroscopy and spot exposure in university hospitals, hospitals, and clinics where perform upper-gastrointestinal X-ray fluoroscopy more than five times every day in Incheon areas. The amount of patient's skin dose during upper-gastrointestinal X-ray fluoroscopy was measured by ionization chamber

In vivo x-ray fluorescence of bone lead in the study of human lead metabolism: Serum lead, whole blood lead, bone lead, and cumulative exposure

International Nuclear Information System (INIS)

Cake, K.M.; Chettle, D.R.; Webber, C.E.; Gordon, C.L.

1995-01-01

Traditionally, clinical studies of lead's effect on health have relied on blood lead levels to indicate lead exposure. However, this is unsatisfactory because blood lead levels have a half-life of approximately 5 weeks, and thus reflect recent exposure. Over 90% of the lead body burden is in bone, and it is thought to have a long residence time, thus implying that measurements of bone lead reflect cumulative exposure. So, measurements of bone lead are useful in understanding the long-term health effects of lead. Ahlgren reported the first noninvasive measurements of bone lead in humans, where γ-rays from 57 Co were used to excite the K series x-rays of lead. The lead detection system at McMaster University uses a 109 Cd source which is positioned at the center of the detector face (HPGe) and a near backscatter (∼160 degrees) geometry. This arrangement allows great flexibility, since one can sample lead in a range of different bone sites due to a robust normalization technique which eliminates the need to correct for bone geometry, thickness of overlying tissue, and other related factors. The effective radiation dose to an adult during an x-ray fluorescence bone lead measurement is extremely low, being 35 nSv. This paper addresses the issue of how bone, whole blood, and serum lead concentrations can be related in order to understand a person's lead exposure history

Low energy (soft) x rays

International Nuclear Information System (INIS)

Hoshi, Masaharu; Antoku, Shigetoshi; Russell, W.J.; Miller, R.C.; Nakamura, Nori; Mizuno, Masayoshi; Nishio, Shoji.

1987-05-01

Dosimetry of low-energy (soft) X rays produced by the SOFTEX Model CMBW-2 was performed using Nuclear Associates Type 30 - 330 PTW, Exradin Type A2, and Shonka-Wyckoff ionization chambers with a Keithley Model 602 electrometer. Thermoluminescent (BeO chip) dosimeters were used with a Harshaw Detector 2000-A and Picoammeter-B readout system. Beam quality measurements were made using aluminum absorbers; exposure rates were assessed by the current of the X-ray tube and by exposure times. Dose distributions were established, and the average factors for non-uniformity were calculated. The means of obtaining accurate absorbed and exposed doses using these methods are discussed. Survival of V79 cells was assessed by irradiating them with soft X rays, 200 kVp X rays, and 60 Co gamma rays. The relative biological effectiveness (RBE) values for soft X rays with 0, 0.2, 0.7 mm added thicknesses of aluminum were 1.6, which were compared to 60 Co. The RBE of 200 kVp X rays relative to 60 Co was 1.3. Results of this study are available for reference in future RERF studies of cell survival. (author)

Shorter exposures to harder X-rays trigger early apoptotic events in Xenopus laevis embryos.

Directory of Open Access Journals (Sweden)

JiaJia Dong

Full Text Available BACKGROUND: A long-standing conventional view of radiation-induced apoptosis is that increased exposure results in augmented apoptosis in a biological system, with a threshold below which radiation doses do not cause any significant increase in cell death. The consequences of this belief impact the extent to which malignant diseases and non-malignant conditions are therapeutically treated and how radiation is used in combination with other therapies. Our research challenges the current dogma of dose-dependent induction of apoptosis and establishes a new parallel paradigm to the photoelectric effect in biological systems. METHODOLOGY/PRINCIPAL FINDINGS: We explored how the energy of individual X-ray photons and exposure time, both factors that determine the total dose, influence the occurrence of cell death in early Xenopus embryo. Three different experimental scenarios were analyzed and morphological and biochemical hallmarks of apoptosis were evaluated. Initially, we examined cell death events in embryos exposed to increasing incident energies when the exposure time was preset. Then, we evaluated the embryo's response when the exposure time was augmented while the energy value remained constant. Lastly, we studied the incidence of apoptosis in embryos exposed to an equal total dose of radiation that resulted from increasing the incoming energy while lowering the exposure time. CONCLUSIONS/SIGNIFICANCE: Overall, our data establish that the energy of the incident photon is a major contributor to the outcome of the biological system. In particular, for embryos exposed under identical conditions and delivered the same absorbed dose of radiation, the response is significantly increased when shorter bursts of more energetic photons are used. These results suggest that biological organisms display properties similar to the photoelectric effect in physical systems and provide new insights into how radiation-mediated apoptosis should be understood and

Paediatric x-ray radiation dose reduction and image quality analysis.

Science.gov (United States)

Martin, L; Ruddlesden, R; Makepeace, C; Robinson, L; Mistry, T; Starritt, H

2013-09-01

Collaboration of multiple staff groups has resulted in significant reduction in the risk of radiation-induced cancer from radiographic x-ray exposure during childhood. In this study at an acute NHS hospital trust, a preliminary audit identified initial exposure factors. These were compared with European and UK guidance, leading to the introduction of new factors that were in compliance with European guidance on x-ray tube potentials. Image quality was assessed using standard anatomical criteria scoring, and visual grading characteristics analysis assessed the impact on image quality of changes in exposure factors. This analysis determined the acceptability of gradual radiation dose reduction below the European and UK guidance levels. Chest and pelvis exposures were optimised, achieving dose reduction for each age group, with 7%-55% decrease in critical organ dose. Clinicians confirmed diagnostic image quality throughout the iterative process. Analysis of images acquired with preliminary and final exposure factors indicated an average visual grading analysis result of 0.5, demonstrating equivalent image quality. The optimisation process and final radiation doses are reported for Carestream computed radiography to aid other hospitals in minimising radiation risks to children.

Paediatric x-ray radiation dose reduction and image quality analysis

International Nuclear Information System (INIS)

Martin, L; Ruddlesden, R; Mistry, T; Starritt, H; Makepeace, C; Robinson, L

2013-01-01

Collaboration of multiple staff groups has resulted in significant reduction in the risk of radiation-induced cancer from radiographic x-ray exposure during childhood. In this study at an acute NHS hospital trust, a preliminary audit identified initial exposure factors. These were compared with European and UK guidance, leading to the introduction of new factors that were in compliance with European guidance on x-ray tube potentials. Image quality was assessed using standard anatomical criteria scoring, and visual grading characteristics analysis assessed the impact on image quality of changes in exposure factors. This analysis determined the acceptability of gradual radiation dose reduction below the European and UK guidance levels. Chest and pelvis exposures were optimised, achieving dose reduction for each age group, with 7%–55% decrease in critical organ dose. Clinicians confirmed diagnostic image quality throughout the iterative process. Analysis of images acquired with preliminary and final exposure factors indicated an average visual grading analysis result of 0.5, demonstrating equivalent image quality. The optimisation process and final radiation doses are reported for Carestream computed radiography to aid other hospitals in minimising radiation risks to children. (paper)

Evaluation device of diagnostic X-ray beam

International Nuclear Information System (INIS)

Pela, Carlos Alberto; Paula, Eldereis de; Bruco, Jose Luiz; Ghilardi Netto, Thomaz

1996-01-01

A device developed to determine the physical parameters useful to the evaluation of both dental and medical X-ray equipment is presented. Nine detectors connected each one to a signal amplifier are used. The amplifiers output has being connected to an analog to digital interface plugged in a PC-AT microcomputer. The X-ray pass through filters before reaching the detectors. The data collected by microcomputer are used to calculate the kVp and other factors as total tube filtration, waveform, half-value layer, exposure rate and exposure time

Real-Time Aircraft Cosmic Ray Radiation Exposure Predictions from the NAIRAS Model

Science.gov (United States)

Mertens, C. J.; Tobiska, W.; Kress, B. T.; Xu, X.

2012-12-01

The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. There is also interest in extending NAIRAS to the LEO environment to address radiation hazard issues for the emerging commercial spaceflight industry. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. Real-time observations are required at a variety of locations within the geospace environment. The NAIRAS model is driven by real-time input data from ground-, atmospheric-, and space-based platforms. During the development of the NAIRAS model, new science questions and observational data gaps were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. The focus of this talk is to present the current capabilities of the NAIRAS model, discuss future developments in aviation radiation modeling and instrumentation, and propose strategies and methodologies of bridging known gaps in current modeling and observational capabilities.

Comparative response of dogs and monkeys to sublethal acute and continuous low dose-rate gamma-ray exposure

International Nuclear Information System (INIS)

Spalding, J.F.; Holland, L.M.; Johnson, O.S.; LaBauve, P.M.; London, J.E.; Prine, J.R.; Vigil, E.A.

1977-02-01

Monkeys (Macaca mulatta) and dogs (beagle) were given thirteen 100-rad gamma-ray doses at 28-day intervals. The comparative response (injury and recovery) of the hematopoietic system of the two species was observed at 7-day intervals during the exposure regime. At 84 days after the thirteenth gamma-ray dose, the 1300-rad conditioned and control dogs and monkeys were challenged continuously with 35 R/day until death to determine the amount of radiation-induced injury remaining in conditioned animals as a reduction in mean survival time. Dogs (50 percent) and monkeys (8 percent) died from injury incurred during the conditioning exposures. Thus, the comparative response of dogs and monkeys to dose protraction by acute dose fractionation was similar to what might be expected from a single acute dose. Mean survival times for nonconditioned dogs and monkeys during continuous exposure at 35 R/day were the same (approximately 1400 h). Thus, hematopoietic response of the two species by this method of dose protraction was not significantly different. Mean survival times of conditioned dogs and monkeys during the continuous 35 R/day gamma-ray challenge exposure were greater than for their control counterparts. Thus, the long-term radiation-induced injury was not measurable by this method. Conditioning doses of more than four times the acute LD 50 - 30 in dogs and approximately two times that of monkeys served only to increase both mean survival time and variance in a gamma-ray stress environment with a dose rate of 35 R/day

Maintaining radiation exposures as low as reasonably achievable (ALARA) for dental personnel operating portable hand-held x-ray equipment.

Science.gov (United States)

McGiff, Thomas J; Danforth, Robert A; Herschaft, Edward E

2012-08-01

Clinical experience indicates that newly available portable hand-held x-ray units provide advantages compared to traditional fixed properly installed and operated x-ray units in dental radiography. However, concern that hand-held x-ray units produce higher operator doses than fixed x-ray units has caused regulatory agencies to mandate requirements for use of hand-held units that go beyond those recommended by the manufacturer and can discourage the use of this technology. To assess the need for additional requirements, a hand-held x-ray unit and a pair of manikins were used to measure the dose to a simulated operator under two conditions: exposures made according to the manufacturer's recommendations and exposures made according to manufacturer's recommendation except for the removal of the x-ray unit's protective backscatter shield. Dose to the simulated operator was determined using an array of personal dosimeters and a pair of pressurized ion chambers. The results indicate that the dose to an operator of this equipment will be less than 0.6 mSv y⁻¹ if the device is used according to the manufacturer's recommendations. This suggests that doses to properly trained operators of well-designed, hand-held dental x-ray units will be below 1.0 mSv y⁻¹ (2% of the annual occupational dose limit) even if additional no additional operational requirements are established by regulatory agencies. This level of annual dose is similar to those reported as typical dental personnel using fixed x-ray units and appears to satisfy the ALARA principal for this class of occupational exposures.

Medical X-ray techniques in diagnostic radiography. 4. ed.

International Nuclear Information System (INIS)

Plaats, G.J. van der; Vijlbrief, P.

1980-01-01

A step by step account is given of every aspect of the technical factors involved in the production of X-ray images. Chapter titles include, methods of image formation and laws of projection, sharpness and unsharpness, contrast, perceptibility of detail in the radiographic image-image quality, properties of fluoroscopic screens, radiographic films, intensifying screens and cassettes, image intensification and X-ray television, processing technique, fluoroscopy and radiographic technique in general, special radiographic techniques, radiographic examinations using contrast media, exposure and exposure tables and automatic density control, diagnostic X-ray apparatus, and diagnostic stands and accessories. (C.F.)

Factors affecting patient dose in diagnostic radiology

International Nuclear Information System (INIS)

Poletti, J.L.

1994-03-01

The report, Factors Affecting Patient Dose in Diagnostic Radiology is divided into three main sections. Part one is introductory and covers the basic principles of x-ray production and image formation. It includes discussion of x-ray generators and x-ray tubes, radiation properties and units, specification and measurement of x-ray beams, methods of patient dose measurement, radiation effects, radiation protection philosophy and finally the essentials of imaging systems. Part two examines factors affecting the x-ray output of x-ray machines and the characteristics of x-ray beams. These include the influence of heat ratings, kVp, waveform, exposure timer, filtration, focus-film distance, beam intensity distribution, x-ray tube age and focal spot size. Part three examines x-ray machine, equipment and patient factors which affect the dose received by individual patients. The factors considered include justification of examinations, choice of examination method, film/screen combinations, kVp, mAs, focus-film distance, collimation and field size, exposure time, projection, scatter, generator calibration errors, waveform, filtration, film processing and patient size. The patient dose implications of fluoroscopy systems, CT scanners, special procedures and mammography are also discussed. The report concludes with a brief discussion of patient dose levels in New Zealand and dose optimisation. 104 refs., 32 figs., 27 tabs

Abdominal x-ray

Science.gov (United States)

Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

SU-E-I-52: Effect of Various X-Ray Beam Qualities On the Exposure Index

International Nuclear Information System (INIS)

Yasumatsu, S; Iwase, K; Shimizu, Y; Tanaka, N; Morishita, J

2015-01-01

Purpose: The exposure index (EI) proposed by the International Electrotechnical Commission (IEC) 62494-1 is expected to be utilized as a standard dose index by every manufacturer. The IEC recommended the usage of RQA5 for the EI. However, X-ray beam qualities, particularly in clinical practices, vary depending on the examination objects and exposure conditions, including usage of anti-scatter grids. We investigated the effects of the X-ray beam qualities other than RQA5 on the EI. Methods: The Xray beam qualities of RQA3, 5, 7, and 9 in IEC 61267 Ed. 1.0 were adopted in a computed radiography system. A uniform exposure without objects was performed to measure the exposure indicators (S values) and air kerma (K). The relational equations between the S values and K were derived for the determination of the EI values. The EI values for RQA3, 7, and 9 were compared to those for RQA5 at the fixed S values of 100, 200, 400, and 600. Finally, the half-value layers (HVLs) using four grids (ratio 6:1, 8:1, 10:1, and 12:1) for the RQA5 X-ray were compared to those with RQA3–9. Results: The EI values for RQA3, 7, and 9 were up to 35.3%, 11.8%, and 38.7% higher, respectively, than that for RQA5 at the S value of 600. The HVLs without grids and with various grids for RQA5 were 6.85 mm Al. and in the range of 6.94–7.29 mm Al. (ΔHVL: up to 0.44 mm Al.), respectively. This variation in the HVLs with grids was smaller than that observed for RQA3–9 (ΔHVL: 2.0–7.5 mm Al.). Conclusion: Although the usage of grids may not greatly affect the EI, the X-ray beam quality for the determination of the EI cannot be ignored in the clinical evaluation of the dose index

Relative biological effectiveness (RBE) of fission neutrons and gamma rays at occupational exposure levels: Volume 1, Studies on the genetic effects in mice of 60 equal once-weekly exposures to fission neutrons and gamma rays

International Nuclear Information System (INIS)

Grahn, D.; Carnes, B.A.

1987-10-01

The relative biological effectiveness (RBE) values for low doses of fission neutrons compared to 60 Co gamma rays were determined with four separate assessments of genetic damage induced in young hybrid male mice. Both radiations were delivered at low dose levels over about one-half the adult lifetime as 60 once-weekly exposures. Genetic damage assessed included both transient and residual injury. The latter is more critical, as residual genetic injury can be transmitted to subsequent generations long after the radiation exposures have ceased. Assays were performed periodically during the 60-week exposure period and at 10 or more weeks after the irradiations had terminated. RBE values, with few exceptions, ranged between 5 and 15 for transient injury and between 25 and 50 for different types of residual genetic injury. The most important form of residual genetic damage in this study was the balanced reciprocal chromosome translocation. These translocations continue to be transmitted throughout reproductive life and can lead to reduced fertility and increased prenatal mortality. The best estimate of the RBE value for translocations was 45 +- 10. Implications and recommendations with regard to the neutron quality factor will be presented conjointly with the findings from the data obtained in this same project on life shortening and on the risks of incidence or death from neoplastic disease. 64 refs., 23 tabs

Determination of point isotropic buildup factors of gamma rays including incoherent and coherent scattering for aluminum, iron, lead, and water by discrete ordinates method

International Nuclear Information System (INIS)

Kitsos, S.; Assad, A.; Diop, C.M.; Nimal, J.C.

1994-01-01

Exposure and energy absorption buildup factors for aluminum, iron, lead, and water are calculated by the SNID discrete ordinates code for an isotropic point source in a homogeneous medium. The calculation of the buildup factors takes into account the effects of both bound-electron Compton (incoherent) and coherent (Rayleigh) scattering. A comparison with buildup factors from the literature shows that these two effects greatly increase the buildup factors for energies below a few hundred kilo-electron-volts, and thus the new results are improved relative to the experiment. This greater accuracy is due to the increase in the linear attenuation coefficient, which leads to the calculation of the buildup factors for a mean free path with a smaller shield thickness. On the other hand, for the same shield thickness, exposure increases when only incoherent scattering is included and decreases when only coherent scattering is included, so that the exposure finally decreases when both effects are included. Great care must also be taken when checking the approximations for gamma-ray deep-penetration transport calculations, as well as for the cross-section treatment and origin

Chemical composition dependence of exposure buildup factors for some polymers

Energy Technology Data Exchange (ETDEWEB)

Singh, Tejbir [Department of Physics, S.D.D.I.E.T., Barwala, District Panchkula, Haryana 134 118 (India)], E-mail: tejbir.s@rediffmail.com; Kumar, Naresh [Department of Physics, Lovely Professional University, Phagwara 144 402 (India)], E-mail: naresh20dhiman@yahoo.com; Singh, Parjit S. [Department of Physics, Punjabi University, Patiala 147 002 (India)], E-mail: dr_parjit@hotmail.com

2009-01-15

Exposure buildup factors for some polymers such as poly-acrylo-nitrile (PAN), poly-methyl-acrylate (PMA), poly-vinyl-chloride (PVC), synthetic rubber (SR), tetra-fluro-ethylene (Teflon) have been computed using the G.P. fitting method in the energy range of 0.015-15.0 MeV, up to the penetration of 40 mean free paths (mfp). The variation of exposure buildup factors for all the selected polymers with incident photon energy at the fixed penetration depths has been studied, mainly emphasizing on chemical composition (equivalent atomic number) of the selected polymers. It has been observed that for the lower penetration depths (below 10 mfp), the exposure buildup factor decreases with the increase in equivalent atomic number of the selected polymers at all the incident photon energies. However, at the penetration depth of 10 mfp and incident photon energy above 3 MeV, the exposure buildup factor becomes almost independent of the equivalent atomic number of the selected polymers. Further, above the fixed penetration depth of 15 mfp of the selected polymers and above the incident photon energy of 3 MeV, reversal in the trend has been observed, i.e., the exposure buildup factor increases with the increase in equivalent atomic number.

Chemical composition dependence of exposure buildup factors for some polymers

International Nuclear Information System (INIS)

Singh, Tejbir; Kumar, Naresh; Singh, Parjit S.

2009-01-01

Exposure buildup factors for some polymers such as poly-acrylo-nitrile (PAN), poly-methyl-acrylate (PMA), poly-vinyl-chloride (PVC), synthetic rubber (SR), tetra-fluro-ethylene (Teflon) have been computed using the G.P. fitting method in the energy range of 0.015-15.0 MeV, up to the penetration of 40 mean free paths (mfp). The variation of exposure buildup factors for all the selected polymers with incident photon energy at the fixed penetration depths has been studied, mainly emphasizing on chemical composition (equivalent atomic number) of the selected polymers. It has been observed that for the lower penetration depths (below 10 mfp), the exposure buildup factor decreases with the increase in equivalent atomic number of the selected polymers at all the incident photon energies. However, at the penetration depth of 10 mfp and incident photon energy above 3 MeV, the exposure buildup factor becomes almost independent of the equivalent atomic number of the selected polymers. Further, above the fixed penetration depth of 15 mfp of the selected polymers and above the incident photon energy of 3 MeV, reversal in the trend has been observed, i.e., the exposure buildup factor increases with the increase in equivalent atomic number

Radiation exposure to the patient during X-ray fluoroscopy and radiography

International Nuclear Information System (INIS)

Dimov, A.; Vassileva, J.

2006-01-01

Full text: The aim of this study is to assess the patient doses received during conventional and digital X-ray radiography, conventional fluoroscopy of the lungs, and one of the highest dose X-ray procedures - contrast examination of the large intestine (Barium enema examination). The measured quantity is Kerma area product (KAP), registered with a clinical dosimeter DRK-1 (Doza, Russia). A total number of 89 patients are included in the study. The Organ doses and Effective doses were assessed using Monte Carlo calculation code (PCXMC 1.4 (Finland). The measurements took place at the following X-ray units: a CGR (Koch and Sterzel) with two working posts - for radiography and fluoroscopy, a Philips Telediagnost (for barium enema) and an Oldelft N800HF Digidelca (for digital radiography of the chest). The typical KAP per procedure at digital radiography, conventional X-ray radiography and fluoroscopy and Barium enema examination are: 17; 95; 928 and 3630 cGy.cm 2 respectively; the average effective doses are: 0.022; 0.053; 0.728 and 8.0 mSv respectively. Doses to the lungs at digital radiography, conventional radiography and fluoroscopy are: 0.066; 0.136 and 2.412 mSv respectively and the dose to the upper and lower large intestine are: 11.7 and 8.6 mSv respectively. Conclusion: The approach used is applicable for assessment of radiation exposure to the patient during X-ray radiography and fluoroscopy. It needs registration of KAP meter readings when this device is installed on the stationary X-ray units

The morphofunctional state of Purkin'e cells in the cerebellum of new-born rats following laser and gamma-ray exposure

International Nuclear Information System (INIS)

Zubkova, S.M.; Popov, V.I.

1993-01-01

Following of local laser (632.8 nm, 6.3. J/cm 2 ) and whole-body Gy gamma-ray exposures of new-born rats the contrast changes of morphometrical indices, RNA amount, and chromatophilia of Purkin'e cells in the cerebellum were seen. The preliminary laser exposure of new-born rat cerebellum artially increased activity of karyogene structures of the cerebellum cells which were inhibited by 6.37 Gy gamma-rays

Factors Associated with Younger Adolescents’ Exposure to Online Alcohol Advertising

Science.gov (United States)

D’Amico, Elizabeth J.; Martino, Steven C.; Collins, Rebecca L.; Shadel, William G.; Tolpadi, Anagha; Kovalchik, Stephanie; Becker, Kirsten M.

2016-01-01

Little is known about the extent and nature of youth exposure to online alcohol advertising, or factors that may be associated with exposure. The current study recruited middle school students who completed a paper survey and then logged each alcohol advertisement that they encountered over a two-week period using cell phones as part of an ecological momentary assessment (EMA) design. We examined the percentage of youth who reported exposure to online alcohol advertising in the past two weeks, average weekly rate of exposure, types of online alcohol advertisements youth reported seeing, and factors that increased youths’ risk of exposure to online alcohol advertising. Analyses are based on 485 participants (47% female; 25% Hispanic, 25% white, 27% black; 6% Asian, 16% other). Youth logged exposures to a total of 3,966 (16,018 weighted for under-reporting) alcohol advertisements across the monitoring period; 154 (568 weighted) or 3.6% were online ads. Seventeen percent of youth reported seeing any online alcohol ad; the majority of online ads seen were video commercials (44.8%) and banner/side ads (26.6%). Factors associated with greater ad exposure were being older, rebellious, and Black race; greater parental monitoring and more hours spent on social media were associated with less exposure. Findings provide important information about adolescents’ exposure to online alcohol advertising and what might contribute to a greater likelihood of exposure. Given that online ad exposure is linked to drinking behavior, prevention programming for younger adolescents should continue to address this issue to help youth make healthy choices regarding alcohol use. PMID:27819430

Exposure to ionizing radiation during dental X-rays is not associated with risk of developing meningioma: a meta-analysis based on seven case-control studies.

Science.gov (United States)

Xu, Ping; Luo, Hong; Huang, Guang-Lei; Yin, Xin-Hai; Luo, Si-Yang; Song, Ju-Kun

2015-01-01

Many observational studies have found that exposure to dental X-rays is associated with the risk of development of meningioma. However, these findings are inconsistent. We conducted a meta-analysis to assess the relationship between exposure to dental X-rays and the risk of development of meningioma. The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR) estimates and 95% confidence intervals (95% CIs) were used to compute the risk of meningioma development according to heterogeneity. Subgroup and sensitivity analyses were performed to further explore the potential heterogeneity. Finally, publication bias was assessed. Seven case-control studies involving 6,174 patients and 19,459 controls were included in the meta-analysis. Neither exposure to dental X-rays nor performance of full-mouth panorex X-rays was associated with an increased risk of development of meningioma (overall: OR, 0.97; 95% CI, 0.70-1.32; dental X-rays: OR, 1.05; 95% CI, 0.89-1.25; panorex X-rays: OR, 1.01; 95% CI, 0.76-1.34). However, exposure to bitewing X-rays was associated with a slightly increased risk of development of meningioma (OR, 1.73; 95% CI, 1.28-2.34). Similar results were obtained in the subgroup and sensitivity analyses. Little evidence of publication bias was observed. Based on the currently limited data, there is no association between exposure to dental X-rays and the risk of development of meningioma. However, these results should be cautiously interpreted because of the heterogeneity among studies. Additional large, high-quality clinical trials are needed to evaluate the association between exposure to dental X-rays and the risk of development of meningioma.

Exposure level of ergonomic risk factors in hotel industries

Science.gov (United States)

Nasrull Abdol Rahman, Mohd; Syahir Muhamad Jaffar, Mohd; Fahrul Hassan, Mohd; Zamani Ngali, Mohd; Pauline, Ong

2017-08-01

Ergonomic Risk Factors (ERFs) which contribute to Musculoskeletal Disorders (MSDs) among room attendants were considered as a problem or trouble since these ERFs would affect their work performance for hotel industries. The purpose of this study was to examine the exposure level of ERFs among room attendants in hotel industries. 65 of respondents were obtained from selected hotels in Peninsular Malaysia. Data were collected by direct observation via Workplace Ergonomic Risk Assessment (WERA) and Quick Exposure Checklist (QEC). There were 36 males and 29 females room attendants involved throughout the research. Most of room attendants experienced high exposure level for back, leg, forceful and vibration based on the exposure level evaluation through WERA while QEC results showed that all room attendants were found to have moderate exposure level for risk factors including back for movement use, shoulders/arms, wrists/hands and neck. All the results obtained showed that the related ERFs for MSDs were associated and essential ergonomic interventions are needed in order to eliminate risk of exposures to MSDs among room attendants in hotel industries.

On the radiation exposure dose and health management history during 50 years of x-ray working

International Nuclear Information System (INIS)

Yoshida, Tomihiro

1981-01-01

My X-ray working history has become 50 years at the end of April, 1980. At this chance, the following data were summarized; the case numbers of X-ray photographs (517,132 cases), total amounts of radiation exposure dose (66.85 roentgen) and the results of blood test, which were experienced during past 50 years. The amounts of exposure dose during 35 years till 1965 were measured using my own method, which measured the film blackening as 30 milli-roentgen per week by certain standard method. After 1966 till 1980, the exposure dose were recorded using that of the film-badge service of Nippon Hoan Yohin Kyokai. The total amounts of exposure dose during 50 years were about 1/4 of D = 5 (N - 18). The results of blood test during last 27 years were found to be normal values. Then, it is happy to say that my body has been protected completely, from radiation hazard as a result of taking radiation protection and checking blood test always at my daily radiation works. The data of my own experiences during 50 years are summarized and reported in this paper. (author)

Absorption correction factor in X-ray fluorescent quantitative analysis

International Nuclear Information System (INIS)

Pimjun, S.

1994-01-01

An experiment on absorption correction factor in X-ray fluorescent quantitative analysis were carried out. Standard samples were prepared from the mixture of Fe 2 O 3 and tapioca flour at various concentration of Fe 2 O 3 ranging from 5% to 25%. Unknown samples were kaolin containing 3.5% to-50% of Fe 2 O 3 Kaolin samples were diluted with tapioca flour in order to reduce the absorption of FeK α and make them easy to prepare. Pressed samples with 0.150 /cm 2 and 2.76 cm in diameter, were used in the experiment. Absorption correction factor is related to total mass absorption coefficient (χ) which varied with sample composition. In known sample, χ can be calculated by conveniently the formula. However in unknown sample, χ can be determined by Emission-Transmission method. It was found that the relationship between corrected FeK α intensity and contents of Fe 2 O 3 in these samples was linear. This result indicate that this correction factor can be used to adjust the accuracy of X-ray intensity. Therefore, this correction factor is essential in quantitative analysis of elements comprising in any sample by X-ray fluorescent technique

Correction of build-up factor one x-ray hvl measurement

International Nuclear Information System (INIS)

Yuliati, Helfi; Akhadi, Mukhlis

2000-01-01

Research to obtain the value build-up factor (b) on half value layers (HVL) measurement of diagnostic X-Rays using pocket dosimeter behind aluminium (AI) filter with its thickness vary from 1 to 4 mm. From the measurement it was obtained HVL value of 1.997, 2.596 and 2.718 mmAI for X-Rays of kVp : 80 Kv with 1, 2, 3 and 4 mm filter thickness respectively. HVL value significantly increase with increasing AI filter thickness. Increasing of HVL means increasing filter thickness. From the calculation it was obtained increasing b value relative to 1 mm AI filter of 18.26 and 46% for filter thickness of 2, 3 and 4 mm respectively. Experiment result shows the need of involving b value in HVL calculation of X-Rays if the filter is relatively thick. Calculation of HVL of X-Rays can be carried out with thin layers filter. Key words : x-rays, half value layer, build up factor

Deformation and stress in PMMA during hard X-ray exposure for deep lithography

International Nuclear Information System (INIS)

Moldovan, N.

1999-01-01

The availability of high-energy, high-flux, collimated synchrotrons radiation has extended the application of deep X-ray lithography (DXRL) to thickness values of the PMMA resist of several millimeters. Some of the most severe limitations come from plastic deformation, stress, and cracks induced in PMMA during exposure and development. We have observed and characterized these phenomena quantitatively. Profilometry measurements revealed that the PMMA is subjected either to local shrinkage or to expansion, while compression and expansion evolve over time. Due to material loss and crosslinking, the material undergoes a shrinkage, while the radiation-induced decomposition generates gases expanding the polymer matrix. The overall dynamics of the material microrelief and stress during and after the exposure depend on the balance between compaction and outgassing. These depend in turn on the exposure conditions (spectrum; dose, dose rate, seaming, temperature), post-exposure storage conditions, PMMA material properties and thickness, and also on the size and geometry of the exposed patterns

Calculation Analysis of Calibration Factors of Airborne Gamma-ray Spectrometer

International Nuclear Information System (INIS)

Zhao Jun; Zhu Jinhui; Xie Honggang; He Qinglin

2009-01-01

To determine the calibration factors of an airborne gamma-ray spectrometer measuring large area gamma-ray emitting source at deferent flying height, a series of Monte Carlo simulations were drawn. Response energy spectrums of NaI crystals in airplane caused by nature-decay-series calibration-pads, and calibration factors on different heights above Cs-137 plane source, were obtained. The calculated results agreed with the experimental data well. (authors)

Thoracic spine x-ray

Science.gov (United States)

Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

Factors associated with younger adolescents' exposure to online alcohol advertising.

Science.gov (United States)

D'Amico, Elizabeth J; Martino, Steven C; Collins, Rebecca L; Shadel, William G; Tolpadi, Anagha; Kovalchik, Stephanie; Becker, Kirsten M

2017-03-01

Little is known about the extent and nature of youth exposure to online alcohol advertising, or factors that may be associated with exposure. The current study recruited middle school students who completed a paper survey and then logged each alcohol advertisement that they encountered over a 2-week period using cell phones as part of an ecological momentary assessment design. We examined the percentage of youth who reported exposure to online alcohol advertising in the past 2 weeks, average weekly rate of exposure, types of online alcohol advertisements youth reported seeing, and factors that increased youths' risk of exposure to online alcohol advertising. Analyses are based on 485 participants (47% female; 25% Hispanic, 25% White, 27% Black; 6% Asian, 16% other). Youth logged exposures to a total of 3,966 (16,018 weighted for underreporting) alcohol advertisements across the monitoring period; 154 (568 weighted) or 3.6% were online ads. Seventeen percent of youth reported seeing any online alcohol ad; the majority of online ads seen were video commercials (44.8%) and banner/side ads (26.6%). Factors associated with greater ad exposure were being older, rebellious, and Black race; greater parental monitoring and more hours spent on social media were associated with less exposure. Findings provide important information about adolescents' exposure to online alcohol advertising and what might contribute to a greater likelihood of exposure. Given that online ad exposure is linked to drinking behavior, prevention programming for younger adolescents should continue to address this issue to help youth make healthy choices regarding alcohol use. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Development of a concept for radiation patients exposure assessment during dental X-ray examinations and statistical data acquisition for the determination of a diagnostic reference value; Erarbeitung eines Konzepts zur Ermittlung der Strahlenexposition von Patienten bei zahnmedizinischen Roentgenuntersuchungen und Erhebung von statistischen Daten zur Erstellung diagnostischer Referenzwerten

Energy Technology Data Exchange (ETDEWEB)

Kueppers, C.; Sering, M. [Oekoinstitut Freiburg e.V., Freiburg (Germany); Poppe, B.; Poplawski, A.; Looe, H.K.; Beyer, D.; Pfaffenberger, A.; Chofor, N.; Eenboom, F. [Pius Hospital, Oldenburg (Germany)

2012-02-15

The research project on the development a concept for radiation patients exposure assessment during dental X-ray examinations and statistical data acquisition for the determination of a diagnostic reference value includes the following issues: Fundamental facts: dental X-ray examination techniques, dose relevant factors and characteristics during X-ray examinations, radiation exposed organs during dental X-ray examinations, dose assessment based on phantoms. Materials and methodologies of the project: TLD measurements using the phantom, calculation of the effective dose during dental X-ray examinations, properties and settings of the reference facilities for the determination of radiation exposure, selection of dental offices, dosimetric measurements, data acquisition and statistical evaluation. Results of dosimetric examinations: results of dosimetric measurements at reference facilities, results of dosimetric measurements in dental offices. Discussion of the concept for the determination of the radiation exposure during dental X-ray examinations.

Exposure to ionizing radiation during dental X-rays is not associated with risk of developing meningioma: a meta-analysis based on seven case-control studies.

Directory of Open Access Journals (Sweden)

Ping Xu

Full Text Available Many observational studies have found that exposure to dental X-rays is associated with the risk of development of meningioma. However, these findings are inconsistent. We conducted a meta-analysis to assess the relationship between exposure to dental X-rays and the risk of development of meningioma.The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR estimates and 95% confidence intervals (95% CIs were used to compute the risk of meningioma development according to heterogeneity. Subgroup and sensitivity analyses were performed to further explore the potential heterogeneity. Finally, publication bias was assessed.Seven case-control studies involving 6,174 patients and 19,459 controls were included in the meta-analysis. Neither exposure to dental X-rays nor performance of full-mouth panorex X-rays was associated with an increased risk of development of meningioma (overall: OR, 0.97; 95% CI, 0.70-1.32; dental X-rays: OR, 1.05; 95% CI, 0.89-1.25; panorex X-rays: OR, 1.01; 95% CI, 0.76-1.34. However, exposure to bitewing X-rays was associated with a slightly increased risk of development of meningioma (OR, 1.73; 95% CI, 1.28-2.34. Similar results were obtained in the subgroup and sensitivity analyses. Little evidence of publication bias was observed.Based on the currently limited data, there is no association between exposure to dental X-rays and the risk of development of meningioma. However, these results should be cautiously interpreted because of the heterogeneity among studies. Additional large, high-quality clinical trials are needed to evaluate the association between exposure to dental X-rays and the risk of development of meningioma.

Digital image acquisition in the X-ray diagnostics. Its influence on the patients' exposure

International Nuclear Information System (INIS)

Hoberg, Bernd; Voigt, Stefan

2012-01-01

Radiation exposure in the classical X-ray diagnostics was continuously reduced during the past years. The annual report 2009 of the Bundesamt fuer Strahlenschutz (BfS) shows that 46% of the radiological examinations in Germany concern the skeleton, the lungs and the digestive and urogenital tract. The respective radiation dose is only 20% of the total dose of the public from X-ray diagnostic measures. Considering computerized tomography, angiography and interventional radiology, that amount to about 10% of the radiological examinations, their dose percentage reaches about 80%. Therefore, the emphasis of modern radiation protection has to be targeted to digital techniques in the future X-ray diagnostics. The authors describe digital detectors, direct and indirect digitalized image receivers, flat-panel detectors and dynamic detectors.

Psychosocial factor exposures in the workplace: differences between immigrants and Spaniards.

Science.gov (United States)

Font, Ariadna; Moncada, Salvador; Llorens, Clara; Benavides, Fernando G

2012-10-01

The purpose of this study was to analyse psychosocial factor exposures in the workplace for immigrant workers in Spain and identify differences in exposure at work between immigrants and Spaniards. A multi-stage sample was taken by conglomerates (final sample size: 7555 workers). The information was obtained in 2004 and 2005 using a standardized questionnaire administered by interviewing participants in their homes. The analysis focused on eight psychosocial factors. For quantitative demands and insecurity, the exposure was defined according to the higher third, and for the others, the exposure was defined according to the lower third. The prevalence ratio (PR) and confidence interval (CI) for unfavourable psychosocial factor, both crude and adjusted, were calculated using log binomial models. Those with highest prevalence of unfavourable psychosocial factor were immigrant manual workers, particularly in low possibilities for development (PR=2.87; 95% CI 2.44-3.73), and immigrant women, particularly in low control over working times (PR=1.72; 95% CI 1.55-1.91). Immigrant workers with manual jobs and immigrant women are the groups most exposed to psychosocial factor. In efforts to prevent these exposures, these inequalities should be taken into account.

Factors affecting outdoor exposure in winter: population-based study

Science.gov (United States)

Mäkinen, Tiina M.; Raatikka, Veli-Pekka; Rytkönen, Mika; Jokelainen, Jari; Rintamäki, Hannu; Ruuhela, Reija; Näyhä, Simo; Hassi, Juhani

2006-09-01

The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study ( n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.

Near-term and late biological effects of acute and low-dose-rate continuous gamma-ray exposure in dogs and monkeys

International Nuclear Information System (INIS)

Spalding, J.F.; Holland, L.M.

1979-07-01

Monkeys (Macaca mulatta) and dogs (beagle) were given thirteen 100-rad gamma-ray doses at 28-day intervals. The comparative response (inury and recovery) of the hematopoietic system of the two species was observed at 7-day intervals during the exposure regime. At 84 days after the thirteenth gamma-ray dose, the 1300-rad conditioned and control dogs and monkeys were challenged continuously with gamma rays at 35 r/day until death to determine the amount of radiation-induced injry remaining in conditioned animals as a reduction in mean survival time. Dogs (50%) and monkeys (8%) died from injury incurred during conditioning exposures. Thus, the comparative response (in terms of lethality) of dogs and monkeys to dose protraction by acute dose fractionation was similar to what we would expect from a single acute dose. The mean survival times for nonconditioned dogs and monkeys during continuous exposure at 35 R/day were the same (approx. 1400 h). Thus, the hematopoietic response of the two species by this method of dose protraction was not significantly different. Mean survival times of conditioned dogs and monkeys during the continuous 35-R/day gamma-ray challenge exposure were greater (significant in dogs but not in monkeys) than for their control counterparts. Thus, long-term radiation-induced injury was not measurable by this method. Conditioning doses of more than 4 times the acute LD 50 30 in dogs and approximately 2 times that in monkeys served only to increase both mean survival time and variance in a gamma-ray stress environment with a dose rate of 35 Rat/day

Recent advances in X-ray lithography

International Nuclear Information System (INIS)

Cerrina, F.

1992-01-01

We report some significant developments in the area of X-ray technology, in the area of the modeling of image formation, in distortion control and in mask replication. Early simple models have been replaced by complete optical calculations based on physical optics and including all relevant factors. These models provide good agreement with the available experimental results. In the area of mask distortions, the use of finite element analysis models has clarified the roles played by the various sources of stress and explained in greater detail the origin of temperature changes. These progress have paved the way to the optimization of the exposure system and to the achievement of the large exposure latitude potential of X-ray lithography. (author)

Incidence and risk factors of occupational blood exposure

DEFF Research Database (Denmark)

Nelsing, S; Nielsen, T L; Brønnum-Hansen, Henrik

1997-01-01

Occupational blood exposures involves a risk of transmission of serious infections. We performed a nation-wide survey, to describe the incidence and risk factors of percutaneous (PCE) and mucocutaneous (MCE) blood exposures among hospital employed doctors in Denmark. Of 9,374 questionnaires, 6......). Only 35% adhered to the basic principles of universal precautions (UP) and non-compliance was associated with a considerably increased risk of both MCE and PCE, especially in non-surgical specialties. In conclusion, we found an unacceptably high incidence of occupational blood exposures among Danish...

Risk evaluation of cosmic-ray exposure in long-term manned space mission

International Nuclear Information System (INIS)

Fujitaka, Kazunobu; Majima, Hideyuki; Ando, Koichi; Yasuda, Hiroshi; Suzuki, Masao

1999-03-01

Long-term manned space missions are planned to be implemented within the first two decades of the 21st century. The International Space Station (ISS) will be ready to run, and a plan to visit Mars is also under way. Humans will live in space for long periods of time and we are planning to do experiments in space to examine various aspects of space science. The main risk in long-term manned space missions is large exposure to space radiation. Human safety must be ensured in space where exposure to cosmic rays is almost 1 mSv a day. As such missions will inevitably result in significant exposure for astronauts, there is increasing need to protect them adequately based on both physical and biological knowledge. A good method to evaluate realistic risk associated with space missions will be in urgent demand. At the National Institute of Radiological Sciences (NIRS), Chiba, Japan, a research institutes of the Science Technology Agency of Japan, high energy cosmic radiation can be simulated only with heavy ion irradiation accelerated by the particle accelerator, Heavy Ion Medical Accelerator (HIMAC). Research to evaluate risk of space radiation, including physical measurement techniques, protective effects, biological effects and risk adjustment, aging, neuronal cell damage and cancer risk are undergoing. We organized a workshop of the latest topics and experimental results of physics and biology related to space radiation supported by Japan Science and Technology Corporation (JST). This workshop was held as a satellite meeting associated with the 32nd Committee on Space Research (COSPAR) Scientific Assembly (Nagoya, July 12-19th, 1998). This volume is an extended proceedings of the workshop. The proceedings contain six main subjects covering the latest information on Risk Evaluation of Cosmic-Ray Exposure in Long-Term Manned Space Mission'. 1. Risk Estimation of Heavy Ion Exposure in Space. 2. Low Dose-Rate Effects and Microbeam-Related Heavy Ions. 3. Chromosome and

X-ray filter for chest X-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

A description is given of an X-ray filter comprised of a sheet of radiation absorbing material with an opening corresponding to the spine and central portion of the heart. The upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter. This filter will permit an acceptable density level of x-ray exposure for the lungs while allowing a higher level of x-ray exposure for the mediastinum areas of the body. (author)

Recommended values of the humidity correction factor k{sub n} for determining exposure in an X-ray beam with free-air chambers; Valores recomendados del factor de correccion por humedad, k{sub h} para la determinacion de la exposicion en un haz de rayos X usando camaras de paredes de aire

Energy Technology Data Exchange (ETDEWEB)

Los Arcos, J M; Brosed, A

1983-07-01

The experimental values stated by CCEMRI (Section I) concerning the humidity correction factor k{sub h} required for determining exposure in an X-ray beam with free-air chambers are commented and a method to estimate k{sub n} numerically, at any particular combination of relative humidity, pressure and temperature, la explained. A table of k{sub h}, calculated for relative humidity varying from 0% to 90%, for pressures in the range of 70 kPa to 104kPa and temperatures between 15 degree centigree and 30 degree centigree, is included. (Author) 10 refs.

Modifications of γ-ray sensitivity of bacterial membranes by pre-exposure to light

International Nuclear Information System (INIS)

Misiti-Dorello, P.; Cancelliere, G.; De Martino, G.; Quintilini, M.

1976-01-01

The exposure of E. coli B/r cells to ultraviolet or to visible light prior to irradiation with γ-rays modifies the sensitivity of the cell membrane to radiation damage responsible for the intracellular K + content. Exposure of bacterial cells to sublethal doses of UV radiation increases their sensitivity to γ-induced membrane damage, while exposure to visible light has the opposite effect. In combined exposures, the visible light, either given before or after the UV always produces a strong photoprotective effect. In either case, the photosensitizing effect of UV is completely suppressed. The photoprotection decays with time if cell suspensions are left in the dark before γ-irradiation. At O 0 C, the half-life of the photoprotective effect is 25 min at pH 7 and 100 min at pH 7.5. The decay is due to the presence of oxygen. The light band responsible for the induction of photoprotection has been estimated to lie in the wavelenght region between 540 and 580 nm. (orig./MG) [de

A few approaches to remove ambiguous factors in x-ray spectrum analysis

International Nuclear Information System (INIS)

Sera, K.; Futatsugawa, S.

1993-01-01

A few attempts have been done to reduce ambiguous factors in the analysis of complex x-ray spectra. Uncertainty in peak identification and separation due to overlapping of x-ray peaks can be reduced by taking into account the response function of x-ray peaks and by using peak functions including all the x-ray sub-lines in a x-ray series. Ambiguous factors due to discontinuity of backgrounds which is sometimes followed by huge peaks can be reduced by considering contributions from the pile-up, escape and tail functions. The problem of uncertainty in the background fitting in a region of low x-ray energy, where many peaks overlap each other and determination of the background function contains much difficulties and ambiguities, can be solved by using peak functions involving tails in place of Gaussians. (author)

X-ray filter for chest x-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

Filter for use in medical x-ray apparatus to permit higher intensity x-ray exposure in the heart and mediastinum area while maintaining a normal level of x-ray exposure in other areas of the body, particlarly in the lung area. The filter comprises a sheet of radiation absorbing material having an opening therein, said opening corresponding to the spine and central portion of the heart. Accordingly, the upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter

Comparison of gamma-ray exposure rate measurements at Bikini Atoll

International Nuclear Information System (INIS)

Gudiksen, P.H.; Crites, T.R.

1975-01-01

A radiological survey of Bikini and Eneu Islands of the Bikini Atoll was conducted during June 1975 to assess the potential radiation doses that may be received by the returning Bikinians. Bikini Atoll was one of the U.S. nuclear weapons testing sites in the Pacific. An integral part of the survey included measurements of the gamma-ray exposure rates at 1 m above the ground with portable NaI instruments at nearly 2700 locations on the two islands. For comparison purposes, similar measurements were made with a pressurized ion chamber at approximately 200 locations, and with LiF and CaF 2 :Dy thermoluminescent dosimeters (TLDs) at 80 locations. The results indicate that the NaI scintillators overresponded because of their nonlinear energy characteristics. The responses of the LiF dosimeters and the pressurized ion chamber agreed to within 13 percent. Attenuation studies with LiF TLDs indicated that roughly 25 percent of the total free air exposure rate at 1 m was due to beta radiation

A study of the energy absorption and exposure buildup factors of some anti-inflammatory drugs

International Nuclear Information System (INIS)

Ekinci, Neslihan; Kavaz, Esra; Özdemir, Yüksel

2014-01-01

Human radiation exposure is increasing due to radiation development in science and technology. The development of radioprotective agents is important for protecting patients from the side effects of radiotherapy and for protecting the public from unwanted irradiation. Radioprotective agents are used to reduce the damage caused by radiation in healthy tissues. There are several classes of radioprotective compounds that are under investigation. Analgesics and anti-inflammatory compounds are being considered for treating or preventing the effects of damage due to radiation exposure, or for increasing the chance of survival after exposure to a high dose of radiation. In this study, we investigated the radioprotective effects of some analgesic and anti-inflammatory compounds by evaluating buildup factors. The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) were calculated to select compounds in a 0.015–15 MeV energy region up to a penetration depth of 40 mfp (mean free path). Variations of EABF and EBF with incident photon energy and penetration depth elements were also investigated. Significant variations in both EABF and EBF values were observed for several compounds at the moderate energy region. At energies below 0.15 MeV, EABF and EBF values increased with decreasing equivalent atomic number (Z eq ) of the samples. In addition, EABF and EBF were the largest for ibuprofen, aspirin, paracetamol, naproxen and ketoprofen at 0.05 and 0.06 MeV, respectively, and the EABF value was 0.1 MeV for aceclofenac. From these results, we concluded that the buildup of photons is less for aceclofenac compared to other materials. - Highlights: • Buildup factors of anti-inflammatory drugs have been calculated by a G-P fitting method. • Z eff of diclofenac was observed higher than other compounds. • It was found that buildup of photons is less for aceclofenac and diclofenac. • It would be appealing to use aceclofenac and diclofenac as radioprotective

Dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation

Energy Technology Data Exchange (ETDEWEB)

Tran, Van; Little, Mark P. [National Cancer Institute, Radiation Epidemiology Branch, Rockville, MD (United States)

2017-11-15

Murine experiments were conducted at the JANUS reactor in Argonne National Laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. The present study reports the reanalysis of the JANUS data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. Mice were mostly Mus musculus, but one experiment used Peromyscus leucopus. For both types of radiation exposure, a Cox proportional hazards model was used, using age as timescale, and stratifying on sex and experiment. The optimal model was one with linear and quadratic terms in cumulative lagged dose, with adjustments to both linear and quadratic dose terms for low-dose rate irradiation (<5 mGy/h) and with adjustments to the dose for age at exposure and sex. After gamma ray exposure there is significant non-linearity (generally with upward curvature) for all tumours, lymphoreticular, respiratory, connective tissue and gastrointestinal tumours, also for all non-tumour, other non-tumour, non-malignant pulmonary and non-malignant renal diseases (p < 0.001). Associated with this the low-dose extrapolation factor, measuring the overestimation in low-dose risk resulting from linear extrapolation is significantly elevated for lymphoreticular tumours 1.16 (95% CI 1.06, 1.31), elevated also for a number of non-malignant endpoints, specifically all non-tumour diseases, 1.63 (95% CI 1.43, 2.00), non-malignant pulmonary disease, 1.70 (95% CI 1.17, 2.76) and other non-tumour diseases, 1.47 (95% CI 1.29, 1.82). However, for a rather larger group of malignant endpoints the low-dose extrapolation factor is significantly less than 1 (implying downward curvature), with central estimates generally ranging from 0.2 to 0.8, in particular for tumours of the respiratory system, vasculature, ovary, kidney/urinary bladder and testis. For neutron exposure most endpoints, malignant and

On micro- and macrocirculatory effects of the whole body exposure to γ-rays in the rabbit

International Nuclear Information System (INIS)

Asano, Makishige; Ohkubo, Chiyoji; Chiba, Masashi

1988-01-01

Immediate and prolonged microcirculatory effects of varying single doses of the whole body exposure of γ-rays irradiation were studied by using the intravital-microscopy concurrently with macrocirculatory hematological determination in the healthy male rabbit. The intravital-microscopy applied to the subcutaneous microcirculatory system in a transparent round-table chamber, that has been installed in advance into the ear lobe, revealed that markedly increased intravascular adhesiveness of white blood cells (WBCs) and extensive stasis similar to the intravascular coagulation of red blood cells (RBCs) developed as immediate changes soon after the γ-rays irradiation regardless of difference of exposure doses such as 50, 250, 500 and 1000 R. Although these changes disappeared within 3 - 4 weeks in animals exposed to 50 R, they persisted throughout the whole experimental period of 4 weeks at higher doses of γ-rays and the extent of the persisting changes appeared to be dose-dependent. Similarly the macrocirculatory changes such as decreases in measurements of RBCs, WBCs, hematocrit values, hemoglobin concentrations, and platelet counts and increase in erythrocyte sedimentation rates were also noticed in a dose-dependent manner. (author)

Risk Factors for Breast Cancer, Including Occupational Exposures

Directory of Open Access Journals (Sweden)

Elisabete Weiderpass

2011-03-01

Full Text Available The knowledge on the etiology of breast cancer has advanced substantially in recent years, and several etiological factors are now firmly established. However, very few new discoveries have been made in relation to occupational risk factors. The International Agency for Research on Cancer has evaluated over 900 different exposures or agents to-date to determine whether they are carcinogenic to humans. These evaluations are published as a series of Monographs (www.iarc.fr. For breast cancer the following substances have been classified as “carcinogenic to humans” (Group 1: alcoholic beverages, exposure to diethylstilbestrol, estrogen-progestogen contraceptives, estrogen-progestogen hormone replacement therapy and exposure to X-radiation and gamma-radiation (in special populations such as atomic bomb survivors, medical patients, and in-utero exposure. Ethylene oxide is also classified as a Group 1 carcinogen, although the evidence for carcinogenicity in epidemiologic studies, and specifically for the human breast, is limited. The classification “probably carcinogenic to humans” (Group 2A includes estrogen hormone replacement therapy, tobacco smoking, and shift work involving circadian disruption, including work as a flight attendant. If the association between shift work and breast cancer, the most common female cancer, is confirmed, shift work could become the leading cause of occupational cancer in women.

Minimizing hospital losses in x-ray films using design of experiments

International Nuclear Information System (INIS)

Aljohani, M.S.; Moreb, A.A.; Naser Al Qasabi; Bandar Sobahi

2004-01-01

Exposure of patients to excessive radiation increases an unnecessary risk of cancer. An X-ray film is considered a reject and is to be repeated if the contrast between the image (picture) of the organ and the films background is low. Applying a two stages approach of Design of Experiments (DOE), this paper considers the factors affecting the contrast of the X-ray film, sorts out the most influential factors and identifies the optimum settings for each factor. Furthermore, the contribution of each factor on the optimal contrast is statistically identified. (Author)

Different gene expression of Normal lymphobloastoid cells which exposure to different dose of 60Co γ-ray

International Nuclear Information System (INIS)

Xiao Yao; Yang Jian; Gao Xian; Qin Yanghua; Sun Ding; Hai Ling

2008-01-01

Objective: To study on the gene expression of normal lymphoblastoid cells(AHH-1) which exposure to difference dose of 60 Co γ-ray, analyses the essential different biological effect.. Methods Human AHH-1 normal line was irradiated by 60 Co γ-rays. Used human cDNA microarray to develop the transcriptional levels of the genes by hybridizing the mRNA of cells 8 h after exposured in different dose and the control cells. Cluster analysis, discrimination and bolting were used to filter the effective genes of differential expression. Results The results of data analysis showed 23 genes of differential expression closely related to biological effect of 2.0 Gy radiation, 5 genes express changed only by 0.5 Gy radiation, 5 genes express apparently both in 2.0 Gy and 0.5 Gy radiation. Conclusion: The different dose γ-rays radiation-induced significant changes in gene expression, such as PAPLN, TP53INP1, PTENP1, FOS and TPR seem to be some important components of cellular radioresponse. (authors)

Stony meteoroid space erosion and drag: Effect on cosmic ray exposure ages

Science.gov (United States)

Rubincam, David Parry

2017-09-01

Collisions with dust particles in retrograde orbits cause space erosion on stony meteoroids in addition to the particle drag which causes drift toward resonances. The spacing between resonances determines the maximum drift time and sets upper limits on the neon-21 cosmic ray exposure (CRE) ages for meteoroids less than ∼1 m in radius, while space erosion controls the limit for radii greater than ∼1 m; the limits accord well with the measured CRE ages of stony meteorites.

Europium- and lithium-doped yttrium oxide nanocrystals that provide a linear emissive response with X-ray radiation exposure

Science.gov (United States)

Stanton, Ian N.; Belley, Matthew D.; Nguyen, Giao; Rodrigues, Anna; Li, Yifan; Kirsch, David G.; Yoshizumi, Terry T.; Therien, Michael J.

2014-04-01

Eu- and Li-doped yttrium oxide nanocrystals [Y2-xO3 Eux, Liy], in which Eu and Li dopant ion concentrations were systematically varied, were developed and characterized (TEM, XRD, Raman spectroscopic, UV-excited lifetime, and ICP-AES data) in order to define the most emissive compositions under specific X-ray excitation conditions. These optimized [Y2-xO3 Eux, Liy] compositions display scintillation responses that: (i) correlate linearly with incident radiation exposure at X-ray energies spanning from 40-220 kVp, and (ii) manifest no evidence of scintillation intensity saturation at the highest evaluated radiation exposures [up to 4 Roentgen per second]. For the most emissive nanoscale scintillator composition, [Y1.9O3; Eu0.1, Li0.16], excitation energies of 40, 120, and 220 kVp were chosen to probe the dependence of the integrated emission intensity upon X-ray exposure-rate in energy regimes having different mass-attenuation coefficients and where either the photoelectric or the Compton effect governs the scintillation mechanism. These experiments demonstrate for the first time for that for comparable radiation exposures, when the scintillation mechanism is governed by the photoelectric effect and a comparably larger mass-attenuation coefficient (120 kVp excitation), greater integrated emission intensities are recorded relative to excitation energies where the Compton effect regulates scintillation (220 kVp) in nanoscale [Y2-xO3 Eux] crystals. Nanoscale [Y1.9O3; Eu0.1, Li0.16] (70 +/- 20 nm) was further exploited as a detector material in a prototype fiber-optic radiation sensor. The scintillation intensity from the [Y1.9O3; Eu0.1, Li0.16]-modified, 400 μm sized optical fiber tip, recorded using a CCD-photodetector and integrated over the 605-617 nm wavelength domain, was correlated with radiation exposure using a Precision XRAD 225Cx small-animal image guided radiation therapy (IGRT) system. For both 80 and 225 kVp energies, this radiotransparent device recorded

Mutation induction in haploid yeast after split-dose radiation exposure. II. Combination of UV-irradiation and X-rays.

Science.gov (United States)

Keller, B; Zölzer, F; Kiefer, J

2004-01-01

Split-dose protocols can be used to investigate the kinetics of recovery from radiation damage and to elucidate the mechanisms of cell inactivation and mutation induction. In this study, a haploid strain of the yeast, Saccharomyces cerevisiae, wild-type with regard to radiation sensitivity, was irradiated with 254-nm ultraviolet (UV) light and then exposed to X-rays after incubation for 0-6 hr. The cells were incubated either on nutrient medium or salt agar between the treatments. Loss of reproductive ability and mutation to canavanine resistance were measured. When the X-ray exposure immediately followed UV-irradiation, the X-ray survival curves had the same slope irrespective of the pretreatment, while the X-ray mutation induction curves were changed from linear to linear quadratic with increasing UV fluence. Incubations up to about 3 hr on nutrient medium between the treatments led to synergism with respect to cell inactivation and antagonism with respect to mutation, but after 4-6 hr the two treatments acted independently. Incubation on salt agar did not cause any change in the survival curves, but there was a strong suppression of X-ray-induced mutation with increasing UV fluence. On the basis of these results, we suggest that mutation after combined UV and X-ray exposure is affected not only by the induction and suppression of DNA repair processes, but also by radiation-induced modifications of cell-cycle progression and changes in the expression of the mutant phenotype. Copyright 2004 Wiley-Liss, Inc.

Activities concerning a re-evaluation of gamma-ray buildup factors in Japan

International Nuclear Information System (INIS)

Hirayama, Hideo

2000-01-01

Research related to gamma-ray buildup factors in Japan are continuing to improve in accuracy and usefulness after the publication of new standard buildup factors as NUREG/CR-5740. Buildup factors for homogeneous materials were studied by three different calculation methods. Several improvements were made to calculate buildup factors up to 40 mfp for various materials for a wide energy range at each code. Systematic data production of buildup factors for multilayer materials were performed by using the EGS4 Monte Carlo code, and were used to improve the fitting formula. These research activities related to gamma-ray buildup factors performed in Japan are presented together with discussions concerning re-evaluation of buildup factors. (author)

Exposure to Low-Dose X-Ray Radiation Alters Bone Progenitor Cells and Bone Microarchitecture.

Science.gov (United States)

Lima, Florence; Swift, Joshua M; Greene, Elisabeth S; Allen, Matthew R; Cunningham, David A; Braby, Leslie A; Bloomfield, Susan A

2017-10-01

Exposure to high-dose ionizing radiation during medical treatment exerts well-documented deleterious effects on bone health, reducing bone density and contributing to bone growth retardation in young patients and spontaneous fracture in postmenopausal women. However, the majority of human radiation exposures occur in a much lower dose range than that used in the radiation oncology clinic. Furthermore, very few studies have examined the effects of low-dose ionizing radiation on bone integrity and results have been inconsistent. In this study, mice were irradiated with a total-body dose of 0.17, 0.5 or 1 Gy to quantify the early (day 3 postirradiation) and delayed (day 21 postirradiation) effects of radiation on bone microarchitecture and bone marrow stromal cells (BMSCs). Female BALBc mice (4 months old) were divided into four groups: irradiated (0.17, 0.5 and 1 Gy) and sham-irradiated controls (0 Gy). Micro-computed tomography analysis of distal femur trabecular bone from animals at day 21 after exposure to 1 Gy of X-ray radiation revealed a 21% smaller bone volume (BV/TV), 22% decrease in trabecular numbers (Tb.N) and 9% greater trabecular separation (Tb.Sp) compared to sham-irradiated controls (P X-rays, whereas osteoclastogenesis was enhanced. A better understanding of the effects of radiation on osteoprogenitor cell populations could lead to more effective therapeutic interventions that protect bone integrity for individuals exposed to low-dose ionizing radiation.

Effects of embryonic and fetal exposure to x-ray, microwaves, and ultrasound

International Nuclear Information System (INIS)

Brent, R.L.

1986-01-01

Many professionals are unfamiliar with radiation biology or the quantitative nature of the risks. Frequently, microwave, ultrasound, and ionizing radiation risks are confused. Although it is impossible to prove no risk for any environmental hazard, it appears that exposure to microwave radiation below the maximal permissible levels present no measurable risk to the embryo. Ultrasound exposure from diagnostic ultrasonographic imaging equipment also is quite innocuous. It is true that continued surveillance and research into potential risks of these low-level exposures should continue, but at present ultrasound not only improves obstetric care but also reduces the necessity of diagnostic x-ray procedures. In the field of ionizing radiation, we have as good a comprehension of the biologic effects and the quantitative maximum risks as of any other environmental hazard. Although the animal and human data support the conclusion that no increases in the incidence of gross congenital malformations, intrauterine growth retardation, or abortion will occur with exposures less than 5 rad, that does not mean that there are definitely no risks to the embryo exposed to lower doses of radiation. Whether there exists a linear or exponential dose-response relationship or a threshold exposure for genetic, carcinogenic, cell-depleting, and life-shortening effects has not been determined. In establishing maximum permissible levels for the embryo at low exposures, refer to Tables 4, 5, 6, 8, and 9. It is obvious that the risks of 1-rad or 5-rad acute exposure are far below the spontaneous risks of the developing embryo because 15 per cent of human embryos abort, 2.7 to 3.0 per cent of human embryos have major malformations, 4 per cent have intrauterine growth retardation, and 8 to 10 per cent have early- or late-onset genetic disease. 98 references

Gardening process of lunar surface layer inferred from the galactic cosmic-ray exposure ages of lunar samples

International Nuclear Information System (INIS)

Iriyama, Jun; Honda, Masatake.

1979-01-01

From the cosmic-ray exposure age data, (time scale 10 7 - 10 8 years), of the lunar surface materials, we discuss the gardening process of the lunar surface layer caused by the meteoroid impact cratering. At steady state, it is calculated that, in the region within 10 - 50 m of the surface, a mixing rate of 10 -4 to 10 -5 mm/yr is necessary to match the exposure ages. Observed exposure ages of the lunar samples could be explained by the gardening effect calculated using a crater formation rate which is slightly modified from the current crater population data. (author)

[Induction of micronuclei in peripheral blood and bone marrow reticulocytes of male mice after subchronic exposure to x-rays and bisphenol A].

Science.gov (United States)

Radzikowska, Joanna; Gajowik, Aneta; Dobrzyńska, Małgorzata

2012-01-01

Ionizing radiation and xenoestrogens are widely present in the human environment. Bisphenol A (BPA) is used to manufacture polycarbonate plastics, epoxy and polyester resins. BPA is present in a great variety of products including: baby bottles, compact disks, thermal paper, safety helmets, bullet resistant laminate, plastic windows, car parts, adhesives, protective coatings, powder paints, polycarbonate bottles and containers, the sheathing of electrical and electronic parts, dental fillings. Food and beverage cans are protected from rusting and corrosion by the application of epoxy resins as inner coatings. Human activities involving the use of radiation and radioactive materials in industry, agriculture and research cause radiation exposure in addition to natural exposure coming from cosmic rays and naturally occurring radioactive substances. The aim of the study was to estimate the effects of bisphenol A, X-rays and combined exposure to X-rays and bisphenol A on the induction of micronuclei in the peripheral blood and in bone marrow reticulocytes of laboratory mice. Pzh-Sfis male mice were exposed for 8 weeks. Animals were treated with bisphenol A diluted in drinking water (5 mg/kg bw, 10 mg/kg bw, 20 mg/kg bw), irradiated 0.05 Gy of X-rays or exposed to a combination of both (0.05 Gy + 5 mg/kg bw BPA). The samples of peripheral blood were taken at 1, 4 and 8 week following the start of exposure, whereas the bone marrow after the end of experiment, only. The induction of micronuclei in reticulocytes were evaluated by using fluorescence microscope. Bisphenol A as well as ionizing radiation stimulated induction of micronuclei in peripheral blood and bone marrow reticulocytes. After the irradiation the level of micronuclei increased, whereas after exposure to BPA decreased related to time expired from beginning of experiment. Combined exposure of ionizing radiation and bisphenol A induced significantly higher frequency of micronuclei compared to the effect

Short irradiation time characteristics of the inverter type X-ray generator

International Nuclear Information System (INIS)

Miyazaki, Shigeru; Hara, Takamitu; Matutani, Kazuo; Saito, Kazuhiko.

1994-01-01

The linearity of the X-ray output is an important factor in radiography. It is a composite of the linearities of the X-ray tube voltage, the X-ray tube current, and the exposure time. This paper focuses on the linearity of exposure time. Non-linearity of the X-ray output for short-time exposure became a problem when the three-phase X-ray generator was introduced. This paper describes the inverter-type X-ray generator, which is expected to become predominant in the future. Previously, we investigated X-ray output linearity during short-time exposure using the technique of dynamic study. In this paper, we describe the application of a digital memory and a personal computer to further investigation. The non-linearity of the X-ray output was caused by irregular waveforms of the X-ray tube voltage found at the rise time and the fall time. When the rise time was about 0.6 ms, the non-linearity was about 2%, which is negligibly small. The non-linearity due to the fall time of the X-ray tube varied greatly according to the X-ray tube current. For the minimum irradiation time of 1 ms, 4% to 27% of the non-linearity was attributable to the fall time. The main cause was the stray capacitance of the X-ray high-voltage cables. When the X-ray tube current exceeded 400 mA, the rise time was almost equal to the fall time, and the problem did not occur. Consequently, the ideal generator should have a fall time which is equal to the rise time of the X-ray tube voltage. Strictly speaking, such a generator should have rectangular waveforms. (author)

Factors associated with occupational exposure to biological material among nursing professionals.

Science.gov (United States)

Negrinho, Nádia Bruna da Silva; Malaguti-Toffano, Silmara Elaine; Reis, Renata Karina; Pereira, Fernanda Maria Vieira; Gir, Elucir

2017-01-01

to identify factors associated with occupational exposure to biological material among nursing professionals. a cross-sectional study was conducted in a high complexity hospital of a city in the state of São Paulo, Brazil. Nursing professionals were interviewed from March to November 2015. All ethical aspects were observed. among the 226 professionals interviewed, 17.3% suffered occupational exposure to potentially contaminated biological material, with 61.5% being percutaneous. Factors such as age (p=0.003), professional experience in nursing (p=0.015), and experience at the institution (p=0.032) were associated with the accidents with biological material. most accidents with biological material among nursing professionals were percutaneous. Age, professional experience, and experience at the institution were considered factors associated with occupational exposure.

Calculation of dose-rate conversion factors for external exposure to photons and electrons

International Nuclear Information System (INIS)

Kocher, D.C.

1978-01-01

Methods are presented for the calculation of dose-rate conversion factors for external exposure to photon and electron radiation from radioactive decay. A dose-rate conversion factor is defined as the dose-equivalent rate per unit radionuclide concentration. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each radiation type and exposure mode, dose-rate conversion factors are derived for tissue-equivalent material at the body surface of an exposed individual. In addition, photon dose-rate conversion factors are estimated for 22 body organs. The calculations are based on the assumption that the exposure medium is infinite in extent and that the radionuclide concentration is uniform. The dose-rate conversion factors for immersion in contaminated air and water then follow from the requirement that all of the energy emitted in the radioactive decay is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated at a reference location above a smooth, infinite plane using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air

Measurement of dose received in knee joint x-ray examination

International Nuclear Information System (INIS)

Abashar, Basamat Musa Hajo

2014-11-01

Diagnostic x-rays examinations play an important role in the health care of the population. These examinations may involve significant irradiation of the patient and probably represent the largest man-made source of radiation exposure for the population. This study was performed in Khartoum Teaching Hospital in period of January to June 2014. This study performed to assess the effective dose (ED) received in knee joint radiographic examination and to analyze dose (ed) received in knee joint radiographic examination and to analyze effective dose distribution among radiological departments under study. The study was performed in Khartoum Teaching Hospital, covering two x-ray units and a sample of 50 patients. The following parameters were recorded age, weight, height, body mass ines (BMI) derived from weight (Kg) and (Height (M)) and (height (m)) and exposure factors. The dose was measured for knee joint x-rays examination. For effective dose calculation, the entrance surface dose (ESD) values were estimated from the x-ray tube output parameters for knee joint Ap and lateral examinations. The ED values were then calculated from the obtained ESD values using IAEA calculation methods. Effective doses were then calculated from energy imparted using ED conversion factors proposed by IAEA. The results of ED values calculated showed that patient exposure were within the normal range of exposure. The mean ED values calculated were( 2.49 + 0.03) and (5.60 + 0.22) milli Grey for knee joint AP and lateral examinations, respectively, Further studies are recommended with more number of patients and using more two modalities for comparison.(Author)

Radiation exposure and image quality in X-ray diagnostic radiology. Physical principles and clinical applications. 2. ed.

International Nuclear Information System (INIS)

Saebel, Manfred; Aichinger, Horst; Dierker, Joachim; Joite-Barfuss, Sigrid

2012-01-01

Diagnostic X-rays are the largest contributor to radiation exposure to the general population, and protecting the patient from radiation damage is a major aim of modern health policy. Once the decision has been taken to use ionising radiation for imaging in a particular patient, it is necessary to optimize the image acquisition process taking into account the diagnostic quality of the images and the radiation dose to the patient. Both image quality and radiation dose are affected by a number of parameters, knowledge of which permits scientifically based decision making. The authors of this second edition of Radiation Exposure and Image Quality in X-ray Diagnostic Radiology have spent many years studying the optimization of radiological imaging. In this book they present in detail the basic physical principles of diagnostic radiology and their application to clinical problems. Particular attention is devoted to evaluation of the dose to the patient, the influence of scattered radiation on image quality, the use of antiscatter grids, and optimization of image quality and dose. The final section is a supplement containing tables of data and graphical depictions of X-ray spectra, interaction coefficients, characteristics of X-ray beams, and other aspects relevant to patient dose calculations. In addition, a complementary CD-ROM contains a user-friendly Excel file database covering these aspects that can be used in the reader's own programs. Since the first edition, the text, figures, tables, and references have all been thoroughly updated, and more detailed attention is now paid to image quality and radiation exposure when using digital imaging and computed tomography. This book will be an invaluable aid to medical physicists when performing calculations relating to patient dose and image quality, and will also prove useful for diagnostic radiologists and engineers. (orig.)

Exposure to hazardous substances in Cathode Ray Tube (CRT) recycling sites in France

Energy Technology Data Exchange (ETDEWEB)

Lecler, Marie-Thérèse, E-mail: marie-therese.lecler@inrs.fr; Zimmermann, François; Silvente, Eric; Clerc, Frédéric; Chollot, Alain; Grosjean, Jérôme

2015-05-15

Highlights: • Chemical risks were assessed in the nine cathode ray tube screens recycling facilities. • The main hazardous agents are dust containing lead, cadmium, barium and yttrium. • Exposure and pollutant levels are described for different operations and processes. • All the operations and processes are concerned by significant levels of pollutants. • We suggest recommendations to reduce chemical risk. - Abstract: The Waste Electrical and Electronic Equipment (WEEE) or e-waste recycling sector has grown considerably in the last fifteen years due to the ever shorter life cycles of consumables and an increasingly restrictive policy context. Cathode Ray Tubes (CRTs) from used television and computer screens represent one of the main sources of e-waste. CRTs contain toxic materials such as lead, cadmium, barium, and fluorescent powders which can be released if recycling of CRTs is not appropriate. Exposure to these harmful substances was assessed in nine workshops where CRT screens are treated. Particulate exposure levels were measured using a gravimetric method and metals were analysed by plasma emission spectrometry. The maximum levels of worker exposure were 8.8 mg/m{sup 3}, 1504.3 μg/m{sup 3}, 434.9 μg/m{sup 3}, 576.3 μg/m{sup 3} and 2894.3 μg/m{sup 3} respectively for inhalable dust, barium, cadmium, lead and yttrium. The maximum levels of airborne pollutants in static samples were 39.0 mg/m{sup 3}, 848.2 μg/m{sup 3}, 698.4 μg/m{sup 3}, 549.3 μg/m{sup 3} and 3437.9 μg/m{sup 3} for inhalable dust, barium, cadmium, lead and yttrium. The most harmful operations were identified, and preventive measures for reducing the chemical risk associated with screen recycling were proposed. Workplace measurements were used to define recommendations for reducing the chemical risks in CRT screens recycling facilities and for promoting the design and development of “clean and safe” processes in emerging recycling channels.

Relationship between X-ray exposure and malignant transformation in C3H 10T1/2 cells

International Nuclear Information System (INIS)

Kennedy, A.R.; Fox, M.; Murphy, G.; Little, J.B.

1980-01-01

The appearance of transformed foci after x-irradiation of the C3H 10T1/2 line of murine cells requires extensive proliferation followed by prolonged incubation under conditions of confluence. When the progeny of irradiated cells are resuspended and plated to determine the number of potential transformed foci, the absolute yield is constant over a wide range of dilutions and is similar to that observed in cultures that have not been resuspended. In addition, for cells exposed to a given x-ray dose, the number of transformed foci per dish is independent of the number of irradiated cells. These observations suggest that few, if any, of the transformed clones occur as a direct consequence of the x-ray exposure and challenge the hypothesis that transformed foci are the clonal products of occasional cells that have experienced an x-ray-induced mutational change. Rather, it appears that at least two steps are involved. We suggest that exposure to x-rays results in a change, for example, the induction or expression of some cell function, in many or all of the cells and that this change is transmitted to the progeny of the surviving cells; a consequence of this change is an enhanced probability of the occurrence of a second step, transformation, when these cells are maintained under conditions of confluence

The influence of plutonium exposure and lung cancer on the frequency of x-ray-induced micronuclei in dog blood lymphocytes

International Nuclear Information System (INIS)

Brooks, A.L.; Rithidech, K.; Muggenburg, B.A.; Lozano, D.; Lundgren, D.L.

1988-01-01

This study determined if lung cancer or exposure to an inhaled alpha emitter, plutonium-239, increased the frequency of micronuclei in blood lymphocytes or altered the responsiveness of lymphocytes to induction of micronuclei by subsequent doses of X rays in vitro. Beagle dogs inhaled 1.5 mm ABAD monodisperse 239 PuO 2 aerosols. The exposure resulted in initial lung burdens of 1.8 KBq to 48 KBq and produced cumulative alpha radiation lung doses of 1.4 to 10.4 Gy at the time of this study. Blood lymphocytes were sampled and irradiated with either 0.0 or 2.0 Gy of X rays. The lymphocytes were stimulated to divide by phytohemagglutinin, cytokinesis was blocked with cytochalasin B, and the frequency of micronuclei was determined in binucleated cells. Plutonium inhalation alone produced no significant increase in the frequency of micronuclei in blood lymphocytes. When 2 Gy of X rays ws given to blood lymphocytes of dogs that had inhaled 239 PuO 2 , there was a linear increase in micronuclei frequency as a function of alpha dose to the lungs; micronuclei/binucleated cell = 0.15 +0.2 D, where D is the cumulative alpha-radiation dose to the lung in Gy. Dogs with 239 PuO 2 - induced lung cancer did not have a significant increase in the frequency of X- ray-induced micronuclei relative to dogs exposed to plutonium that did not have lung cancer. These data suggest that inhaled 239 PuO 2 alters the responsiveness of blood lymphocytes to subsequent X-ray exposure. (author)

Neck x-ray

Science.gov (United States)

X-ray - neck; Cervical spine x-ray; Lateral neck x-ray ... There is low radiation exposure. X-rays are monitored so that the lowest amount of radiation is used to produce the image. Pregnant women and ...

Determination of energy absorbed during X-ray exposure of the forearm by means of thermoluminescent dosimetry

International Nuclear Information System (INIS)

Hofmann, E.

1982-01-01

LiF dose meters were used to determine radiation doses in conventional X-ray diagnostic pictures of the forearm. The paper describes a method for determining integral doses by using these dose meters. It describes in detail how a phantom forearm apt for the purpose is to be made. In the Federal Republic of Germany, malignant growth incidence due to X-ray pictures of the forearm is enhanced by about .01 cases each year. The malignant growth incidence rate caused by X-ray diagnostic measures is low. It is therefore generally justified to neglect limbs in exemplary studies of radiation exposure. All calculations and considerations took into account that all possible radiation protection measures have been duly applied. (orig./DG) [de

Calculation of neutron and gamma-ray flux-to-dose-rate conversion factors

International Nuclear Information System (INIS)

Kwon, S.G.; Lee, S.Y.; Yook, C.C.

1981-01-01

This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute (ANSI) N666. These data are used to calculate the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoenergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions. (author)

Implication of occupational exposure to X-Rays diagnosed during pregnancy

International Nuclear Information System (INIS)

Frometa Suarez, Ileana

1998-01-01

At the present time the risks have been described thoroughly and goods on the inherent fetus to the exhibition give sources ionizing radiations in women that are in period gestation. Presently investigation work is carried out for survey of women exposed to occupational ionizing radiations in reproductive age. The incidence is described and behavior gives these goods and its relationship with other risk factors. In this study the exposure to ionizing radiations is not revealed as main causal factor risk

Calculation of Dose Gamma Ray Build up Factor in Some ...

African Journals Online (AJOL)

The gamma ray buildup factor was calculated by analyzing the narrow- beam and broad-beam geometry equations using Taylor's formula for isotropic sources and homogeneous materials. The buildup factor was programmed using MATLAB software to operate with any radiation energy (E), atomic number (Z) and the ...

Effects of occupational exposure of X-Ray on hematological parameters of diagnostic technicians

Science.gov (United States)

Taqi, Ali H.; Faraj, Kharman A.; Zaynal, Sarah A.; Hameed, Ahmed M.; Mahmood, Abd-Alkader A.

2018-06-01

The aim of this study was to identify the effects of long term exposure of X-ray on diagnostic technicians which they work at Kirkuk hospitals through examining some hematological parameters which are white blood cells (WBC), Neutrophils, Lymphocyte, Monocyte, Eosinophil, Basophil, Reactive Lymphocyte, red blood cells (RBC), hemoglobin (Hb), hematocrit (HCT), Mean Cell Volume (MCV), Mean Corpuscular Hemoglobin (MCH), Mean Cell Hemoglobin Concentration (MCHC), Red Cell Distribution Width (RDW), Platelet (PLT). The study included 54 male diagnostic technicians and 54 male healthy controls match with the first group to show any alteration of the hematological parameters. The diagnostic technicians divided into two groups depending on their work experience and hours working per day. The statistical analysis was performed using (Graph-pad) program. Our results showed that the Complete blood cells count (CBC) parameters (Neutrophil, Monocytes, Basophile, MCV, RDW and PLT) significantly (Pgroups of the diagnostic technicians compared with their controls. We concluded that chronic exposure of X-ray can significantly alter some hematological parameters and the number of hours working per day has observable effects on the some hematological parameters. We recommended training and courses about hazard of ionizing radiation should be organized for enhance the healthcare quality of the technicians and to improve their knowledge about benefit of radiation protection tools to protect themselves from any overexposure during the daily life.

X-ray holography: X-ray interactions and their effects

International Nuclear Information System (INIS)

London, R.A.; Trebes, J.E.; Rosen, M.D.

1988-01-01

The authors summarize a theoretical study of the interactions of x-rays with a biological sample during the creation of a hologram. The choice of an optimal wavelength for x-ray holography is discussed, based on a description of scattering by objects within an aqueous environment. The problem of the motion resulting from the absorption of x-rays during a short exposure is described. The possibility of using very short exposures in order to capture the image before motion can compromise the resolution is explored. The impact of these calculation on the question of the feasibility of using an x-ray laser for holography of biological structures is discussed. 12 refs., 2 figs

Occupational exposure to organic solvents: a risk factor for pulmonary veno-occlusive disease.

Science.gov (United States)

Montani, David; Lau, Edmund M; Descatha, Alexis; Jaïs, Xavier; Savale, Laurent; Andujar, Pascal; Bensefa-Colas, Lynda; Girerd, Barbara; Zendah, Inès; Le Pavec, Jerome; Seferian, Andrei; Perros, Frédéric; Dorfmüller, Peter; Fadel, Elie; Soubrier, Florent; Sitbon, Oliver; Simonneau, Gérald; Humbert, Marc

2015-12-01

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension characterised by predominant remodelling of pulmonary venules. Bi-allelic mutations in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene were recently described as the major cause of heritable PVOD, but risk factors associated with PVOD remain poorly understood. Occupational exposures have been proposed as a potential risk factor for PVOD, but epidemiological studies are lacking.A case-control study was conducted in consecutive PVOD (cases, n=33) and pulmonary arterial hypertension patients (controls, n=65). Occupational exposure was evaluated via questionnaire interview with blinded assessments using an expert consensus approach and a job exposure matrix (JEM).Using the expert consensus approach, PVOD was significantly associated with occupational exposure to organic solvents (adjusted OR 12.8, 95% CI 2.7-60.8), with trichloroethylene being the main agent implicated (adjusted OR 8.2, 95% CI 1.4-49.4). JEM analysis independently confirmed the association between PVOD and trichloroethylene exposure. Absence of significant trichloroethylene exposure was associated with a younger age of disease (54.8±21.4 years, p=0.037) and a high prevalence of harbouring bi-allelic EIF2AK4 mutations (41.7% versus 0%, p=0.015).Occupational exposure to organic solvents may represent a novel risk factor for PVOD. Genetic background and environmental exposure appear to influence the phenotypic expression of the disease. Copyright ©ERS 2015.

Monte Carlo simulation of x-ray buildup factors of lead and its applications in shielding of diagnostic x-ray facilities

International Nuclear Information System (INIS)

Kharrati, Hedi; Agrebi, Amel; Karaoui, Mohamed-Karim

2007-01-01

X-ray buildup factors of lead in broad beam geometry for energies from 15 to 150 keV are determined using the general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C). The obtained buildup factors data are fitted to a modified three parameter Archer et al. model for ease in calculating the broad beam transmission with computer at any tube potentials/filters combinations in diagnostic energies range. An example for their use to compute the broad beam transmission at 70, 100, 120, and 140 kVp is given. The calculated broad beam transmission is compared to data derived from literature, presenting good agreement. Therefore, the combination of the buildup factors data as determined and a mathematical model to generate x-ray spectra provide a computationally based solution to broad beam transmission for lead barriers in shielding x-ray facilities

Factors influencing in situ gamma-ray measurements

Science.gov (United States)

Loonstra, E. H.; van Egmond, F. M.

2009-04-01

Introduction In situ passive gamma-ray sensors are very well suitable for mapping physical soil properties. In order to make a qualitative sound soil map, high quality input parameters for calibration are required. This paper will focus on the factors that affect the output of in situ passive gamma-ray sensors, the primary source, soil, not taken into account. Factors The gamma-ray spectrum contains information of naturally occurring nuclides 40K, 238U and 232Th and man-made nuclides like 137Cs, as well as the total count rate. Factors that influence the concentration of these nuclides and the count rate can be classified in 3 categories. These are sensor design, environmental conditions and operational circumstances. Sensor design The main elements of an in situ gamma-ray sensor that influence the outcome and quality of the output are the crystal and the spectrum analysis method. Material and size of the crystal determine the energy resolution. Though widely used, NaI crystals are not the most efficient capturer of gamma radiation. Alternatives are BGO and CsI. BGO has a low peak resolution, which prohibits use in cases where man-made nuclides are subject of interest. The material is expensive and prone to temperature instability. CsI is robust compared to NaI and BGO. The density of CsI is higher than NaI, yielding better efficiency, especially for smaller crystal sizes. More volume results in higher energy efficiency. The reduction of the measured spectral information into concentration of radionuclides is mostly done using the Windows analysis method. In Windows, the activities of the nuclides are found by summing the intensities of the spectrum found in a certain interval surrounding a peak. A major flaw of the Windows method is the limited amount of spectral information that is incorporated into the analysis. Another weakness is the inherent use of ‘stripping factors' to account for contributions of radiation from nuclide A into the peak of nuclide B. This

[Radiation exposure of children in pediatric radiology. Part 5: organ doses in chest radiography].

Science.gov (United States)

Seidenbusch, M C; Schneider, K

2009-05-01

Reconstruction of organ doses of selected organs and tissues from radiographic settings and exposure data collected during chest X-ray examinations of children of various age groups performed in Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007. The dosimetric data of all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 119 150 chest radiographs of all age groups. Reconstruction of organ doses in 40 organs and tissues in X-ray examinations of the chest was performed based on the conversion factor concept. The radiation exposure of organs in projection radiography is determined by the exact site of the organs relative to the edges of the X-ray field and the beam direction of X-rays. Optimal collimation in chest radiography can reduce the exposure of organs located at the periphery of the X-ray field, e. g. thyroid gland, stomach and partially the liver, by a factor of 2 to 3, while organs located in the center of the X-ray-field, e. g. thymus, breasts, lungs, esophagus and red bone marrow, are not affected by exact collimation. The high frequency of the roentgen examination of the chest in early age groups increases the collective radiation burden to radiosensitive organs. Therefore, radiation protection of the patient during chest radiographies remains of great importance.

Analysis of chromosomal abnormalities: a study of partial exposure to X-rays

Energy Technology Data Exchange (ETDEWEB)

Andrade, Aida M.G. de; Mendes, Mariana E.; Mendonça, Julyanne C.G.; Melo, Laís; Hwang, Suy; Santos, Neide; Lima, Fabiana F. de, E-mail: aidamgandrade@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Centro Regional de Ciências Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Universidade Federal de Pernambuco (UFPE),Recife (Brazil). Centro de Biociências. Departamento de Genética

2017-11-01

Biological dosimetry is used in case of supposed accidental overexposure. The most commonly used biomarkers for assessing the absorbed dose are unstable chromosomal abnormalities. In a case of a partial body exposure, the frequencies of those abnormalities varies according to the area of the exposed body and may be substantially different from a total exposure of the body with an identical dose. The present study aimed to evaluate the frequency of chromosomal changes simulating, with blood samples, partial (25%, 50%) and full body irradiation (100%) in X-ray beam. The irradiation was performed at Metrology Service (CRCN-NE / CNEN) with a bundle of 250kVp X-rays, resulting in the absorbed dose of 1.0 Gy. Prior to obtain the metaphases, irradiated blood was mixed with non-irradiated blood, and then the mitotic metaphases for the chromosomal analyzes were obtained by culturing lymphocytes and the slides were stained with 5% Giemsa. It was observed that there was an increase in dicentric frequency when the dose percentage increases in both subjects (0.024 and 0.049 in subject 1 and 0.016 and 0.038 in subject 2) after irradiation. The cellular distribution was 'contaminated' only at dose 25% of the first individual who had a prolongation of the distribution. The Qdr and Dolphin methods were used to estimate partial absorbed dose, but the Qdr method was not efficient and whereas the Dolphin method was efficient when the individual had a prolonged cell distribution. It is necessary to increase the number of observations to be sure of the observed behaviors. (author)

Analysis of chromosomal abnormalities: a study of partial exposure to X-rays

International Nuclear Information System (INIS)

Andrade, Aida M.G. de; Mendes, Mariana E.; Mendonça, Julyanne C.G.; Melo, Laís; Hwang, Suy; Santos, Neide; Lima, Fabiana F. de; Centro Regional de Ciências Nucleares; Universidade Federal de Pernambuco

2017-01-01

Biological dosimetry is used in case of supposed accidental overexposure. The most commonly used biomarkers for assessing the absorbed dose are unstable chromosomal abnormalities. In a case of a partial body exposure, the frequencies of those abnormalities varies according to the area of the exposed body and may be substantially different from a total exposure of the body with an identical dose. The present study aimed to evaluate the frequency of chromosomal changes simulating, with blood samples, partial (25%, 50%) and full body irradiation (100%) in X-ray beam. The irradiation was performed at Metrology Service (CRCN-NE / CNEN) with a bundle of 250kVp X-rays, resulting in the absorbed dose of 1.0 Gy. Prior to obtain the metaphases, irradiated blood was mixed with non-irradiated blood, and then the mitotic metaphases for the chromosomal analyzes were obtained by culturing lymphocytes and the slides were stained with 5% Giemsa. It was observed that there was an increase in dicentric frequency when the dose percentage increases in both subjects (0.024 and 0.049 in subject 1 and 0.016 and 0.038 in subject 2) after irradiation. The cellular distribution was 'contaminated' only at dose 25% of the first individual who had a prolongation of the distribution. The Qdr and Dolphin methods were used to estimate partial absorbed dose, but the Qdr method was not efficient and whereas the Dolphin method was efficient when the individual had a prolonged cell distribution. It is necessary to increase the number of observations to be sure of the observed behaviors. (author)

Ultrastructural changes in spermatogonia of Wistar strain rats following acute whole-body X-ray exposure

Energy Technology Data Exchange (ETDEWEB)

Hrehorovsky, M; Horak, J [Univerzita P.J. Safarika, Kosice (Czechoslovakia). Katedra Vseobecnej Biologie

1980-01-01

Changes in spermatogonia ultrastructure in rats of Wistar strain after single whole-body X-ray irradiation with 6.4 mC.kg/sup -1/, 25.8 mC.kg/sup -1/ and 51.6 mC.kg/sup -1/ respectively, were studied. Intracellular spaces were found between spermatogonia enlarged, nuclear membranes were bent, the pheripheral teritories of chromation were electronoptically denser, the morphology of nucleoli was changed, cytoplasm was vacuolised, mitochondria were damaged, the vacuolar dilatation of agranular endoplasmic reticulum was evident and electronoptically empty vacuoles near the Golgi complex occured 48 hours after single whole-body X-ray irradiation. Qualitative changes in the ultrastructure of individual types of spermatogonia after individual exposures were similar.

Contribution of cosmic rays to radiation exposure of the population

International Nuclear Information System (INIS)

Sztanyik, L.B.; Nikl, I.

1982-01-01

To evaluate the exposure of the Hungarian population to cosmic rays, the absorbed dose rate in air of cosmic radiation was directly measured by high pressure ionization chamber at ground level on the surface of different bodies of water and at various altitudes on the board of an aircraft. From the dose rates measured this way, the outdoor dose equivalent rate from the ionizing components of cosmic radiation to people living at sea level would be 300-325 μSv per year. Taking into account the altitude distribution of the population, the average weighted dose equivalent is about 320 μSv per year. At Kekestetoe, the highest peak of the Matra Mountains, (the highest altitude in Hungary), the annual dose equivalent is about 50 per cent higher than on the Great Hungarian Plain. (author)

Statistical investigation on frequency, duration, number of X-ray investigations and radiation exposure to the patients of a district hospital on the outskirts of Munich

Energy Technology Data Exchange (ETDEWEB)

Nordmann, W

1973-04-10

Within the framework of a dissertation, X-ray examined patients were statistically surveyed during one month at the district hospital. The radiation exposure of the patients increased strongly particularly with men of the age of 21 to 30 and of 61 to 70. The causes are the multiply performed investigations after accidents as well as angiography at greater ages. The exposure is in the case of women particularly high between the ages of 66 and 70. In determining the gonadal exposure, the average values for the X-ray investigation at the time were referred to. The numbers give an approximate idea of to what extent single investigations with varying investigation or picture frequency can contribute to gonadal exposure.

Evaluation of natural radiation exposure of the French population

International Nuclear Information System (INIS)

Billon, S.; Morin, A.; Baysson, H.; Gambard, J.P.; Rannou, A.; Tirmarche, M.; Laurier, D.; Caer, S.

2004-01-01

Exposure of the French population to ionising radiation is mainly due to natural radiation (i.e. exposure through: inhalation of radon decay products, external radiation of terrestrial and cosmic origin and water and food ingestion). In an epidemiological context, it is necessary to estimate as precisely as possible the population exposure, in order to study its influence on health indicators. In this aim, indicators of population exposure should be created taking into account results of environmental measurements by controlling the different factors that may influence these measurements (dwelling characteristics, seasonal variations, population density). The distribution of these exposures should also be studied at different geographical levels (department, job area). This work updates the estimation of the French population exposure to natural radiation. Radon exposure indicators have been based on concentrations measured in dwellings, corrected on season and dwelling characteristics (departmental range: 19-297 Bq/m 3 ). Indicators of terrestrial gamma ray exposure have been based on measured indoor and outdoor dose rates adjusted on dwelling characteristics (22-95 nSv/h). Cosmic ray exposure has been evaluated from altitude and weighted by population density (0.27-0.38 mSv/yr). Due to these three components, the effective annual dose was estimated to be at 2.2 mSv. (author)

γ-ray induced chromosome aberration in rabbit peripheral blood lymphocytes irradiated in partial and whole body and decline of aberration rate with time post-exposure

International Nuclear Information System (INIS)

Zhang Lianzhen; Deng Zhicheng; Wang Haiyan

1997-01-01

Te author presents the results of study on 60 Co γ-ray induced chromosome aberration in rabbits peripheral blood lymphocytes irradiated in partial and whole body and the aberration rate decrease with the time of post-exposure. The experiments included 5 groups, it was whole-body exposure group, partial-body exposure (abdomen and pelvic cavity) group, blood irradiation group in vitro and control group respectively. Radiation dose was 3.0 Gy delivered at rate of 0.5 Gy/min. The results show that it was no significant differences between whole body and in blood irradiation group. The chromosome aberration yield in whole body exposure group was higher than that in partial-body group and in the abdomen exposure group was higher than in that in the pelvic cavity irradiation; The chromosome aberration rate decreased with the time of post-exposure in partial and whole body by γ-ray irradiation

Study on exposures in incidents situations involving X-ray generators of industrial use

International Nuclear Information System (INIS)

Rios, Paulo B.; Rios, Denise A. da S.

2014-01-01

Case studies of accidents involving radiation sources provides valuable information for the improvement of equipment and procedures to be adopted to prevent their recurrence. Therefore, they are recommended as part of the licensing process of radiative facilities. However, when the equipment has no radiological protection requirements or have no record of accidents, an effective method to appropriate this knowledge necessary to improvements of process and project is the investigation of reported incidents and the proposition limit situations where exposures unlikely and even low intensity can occur. This work reviews incidents in X-ray equipment and thickness meters. Emergency situations are also studied in this type of equipment and in an accelerator of electrons self-shielded for curing of paints and varnishes. The exposure estimates are calculated from data collected in workplaces on the distance and time for each proposed case. Although there is no severe consequences to occupational health, the results can be used to improve the quality of training for operators and maintenance technicians, for proposing of new alarm systems and emergency teams procedures and may serve as a warning in inadvertent and avoidable situations of unnecessary exposures

X-ray diagnostic study on the optimization of digital radiography in dentistry. Optimal exposure conditions for X-ray CCD sensor

International Nuclear Information System (INIS)

Hakata, Toshifumi

2002-01-01

The purpose of this research is to reduce the patient dose by optimization of irradiation conditions of an X-ray CCD sensor in intra-oral digital radiography. The X-ray diagnosis was divided into two, high quality-of-image diagnosis and low quality-of-image diagnosis, and it optimized by using the exposure of necessary minimum for each. The image quality of CCD was evaluated using the signal-to-noise ratio (SNR) in order to estimate the influence of irradiation conditions. The dose based on CCD maker setting value was set up so that the highest quality of image might be obtained mostly. In low quality-of-image diagnosis, even if it reduced the dose to 13.2% of standard irradiation, SNR was 40% and interpretation was possible. In high quality-of-image diagnosis, even if it reduces the dose to 49% of standard irradiation, SNR remained 80% and there were few differences of the image with a standard. A study of the digital X-ray examination taken at the dental clinic showed high quality-of-image diagnosis was 69% and low quality-of-image one was 31%. When this optimization was performed, it was presumed that reduction of about 62% of the dose is possible. (author)

Aberrant cell divisions in root meristeme of maize following exposure to X-rays low doses compared to similar effects of 50 Hz electromagnetic exposure

Directory of Open Access Journals (Sweden)

Luchian T.

2012-04-01

Full Text Available The response of maize to radiation exposure was investigated by two cytogenetic methods considering the importance of the geno-toxic effect for environmental and agricultural purposes. Uniform genophond seeds, freshly germinated, were exposed to relatively low radiation doses using a radiotherapy X-ray applicator from a hospital irradiation device and to a 50 Hz electromagnetic field with about 10 mT magnetic induction (generated within laboratory assembled electromagnetic coils. Radicular meristeme tissue aliquots were prevailed for cytogenetic investigation based on microscopic observations and cell counting. Microscope slides were prepared following a specific procedure (squash technique and Feulgen method based on modified Carr reactive coloration. Mitotic index as well as chromosomal aberration percentage were calculated for more than 30,000 cells taken into account. From a qualitative viewpoint, chromosomal aberrations such as interchromatidian bridges, lagging and expelled chromosomes and multipolar divisions were evidenced - no distinct situation for either ionizing radiation or electromagnetic field being identified. The main quantitative difference consisted in the increased mitotic index for electromagnetic exposure increased times compared with the diminished mitotic index in the case of low X-ray doses.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. ... x-rays. A Word About Minimizing Radiation Exposure Special care is taken during x-ray examinations to ...

Evaluation of environmental radiation exposure

International Nuclear Information System (INIS)

Imai, Kazuhiko

1974-01-01

The environmental radiation exposure due to radioactive rare gases is most important both at the time of reactor accidents and also in the long-term normal operation of reactor plants. The exposure dose is usually calculated by means of computers. The procedure of the calculation on environmental exposure dose is divided in several consecutive steps. The calculational formulae frequently used and those proposed recently are given with the explanation on released radionuclides, release to the atmosphere, concentration in the atmosphere, β-ray exposure, γ-ray exposure, and calculation of long-term exposure dose. (Mori, K.)

Biological dose estimation for accidental supra-high dose gamma-ray exposure

International Nuclear Information System (INIS)

Chen, Y.; Yan, X.K.; Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K.

2011-01-01

To correctly estimate the biological dose of victims accidentally exposed to a very high dose of 60 Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of 60 Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0 -3 D 2 . Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy γ-irradiation from a supra-high dose 60 Co gamma-ray accident.

Detective quantum efficiency: a standard test to ensure optimal detector performance and low patient exposures

Science.gov (United States)

Escartin, Terenz R.; Nano, Tomi F.; Cunningham, Ian A.

2016-03-01

The detective quantum efficiency (DQE), expressed as a function of spatial frequency, describes the ability of an x-ray detector to produce high signal-to-noise ratio (SNR) images. While regulatory and scientific communities have used the DQE as a primary metric for optimizing detector design, the DQE is rarely used by end users to ensure high system performance is maintained. Of concern is that image quality varies across different systems for the same exposures with no current measures available to describe system performance. Therefore, here we conducted an initial DQE measurement survey of clinical x-ray systems using a DQE-testing instrument to identify their range of performance. Following laboratory validation, experiments revealed that the DQE of five different systems under the same exposure level (8.0 μGy) ranged from 0.36 to 0.75 at low spatial frequencies, and 0.02 to 0.4 at high spatial frequencies (3.5 cycles/mm). Furthermore, the DQE dropped substantially with decreasing detector exposure by a factor of up to 1.5x in the lowest spatial frequency, and a factor of 10x at 3.5 cycles/mm due to the effect of detector readout noise. It is concluded that DQE specifications in purchasing decisions, combined with periodic DQE testing, are important factors to ensure patients receive the health benefits of high-quality images for low x-ray exposures.

Factors associated with secondhand smoke exposure in different settings: Results from the German Health Update (GEDA) 2012.

Science.gov (United States)

Fischer, Florian; Kraemer, Alexander

2016-04-14

The ubiquity of secondhand smoke (SHS) exposure at home or in private establishments, workplaces and public areas poses several challenges for the reduction of SHS exposure. This study aimed to describe the prevalence of SHS exposure in Germany and key factors associated with exposure. Results were also differentiated by place of exposure. A secondary data analysis based on the public use file of the German Health Update 2012 was conducted (n = 13,933). Only non-smokers were included in the analysis. In a multivariable logistic regression model the factors associated with SHS exposure were calculated. In addition, a further set of multivariable logistic regressions were calculated for factors associated with the place of SHS exposure (workplace, at home, bars/discotheques, restaurants, at the house of a friend). More than a quarter of non-smoking study participants were exposed to SHS. The main area of exposure was the workplace (40.9 %). The multivariable logistic regression indicated young age as the most important factor associated with SHS exposure. The odds for SHS exposure was higher in men than in women. The likelihood of SHS exposure decreased with higher education. SHS exposure and the associated factors varied between different places of exposure. Despite several actions to protect non-smokers which were implemented in Germany during the past years, SHS exposure still remains a relevant risk factor at a population level. According to the results of this study, particularly the workplace and other public places such as bars and discotheques have to be taken into account for the development of strategies to reduce SHS exposure.

Gamma-Ray Bursts and Relativistic Shells: The Surface Filling Factor

International Nuclear Information System (INIS)

Fenimore, E.E.; Cooper, C.; Ramirez-Ruiz, E.; Sumner, M.C.; Yoshida, A.; Namiki, M.

1999-01-01

The variability observed in many complex gamma-ray bursts (GRBs) is inconsistent with causally connected variations in a single, symmetric, relativistic shell interacting with the ambient material (open-quotes external shocksclose quotes). Rather, either the central site must produce ∼10 50 ergs s -1 for hundreds of seconds (open-quotes internal shocksclose quotes), or the local spherical symmetry of the shell must be broken on an angular scale much smaller than Γ -1 , where Γ is the bulk Lorentz factor for the shell. The observed variability in the external shock models arises from the number of causally connected regions that (randomly) become active. We define the surface filling factor to be the ratio of the area of causally connected regions that become active to the observable area of the shell. From the observed variability in 52 BATSE bursts, we estimate the surface filling factor to be typically ∼5x10 -3 , although some values are near unity. We find that the surface filling factor, f, is ∼0.1ΔT/T in both the constant Γ phase (which probably produces the GRB) and the decelerating phase (which probably produces the X-ray afterglows). Here, ΔT is a typical timescale of variability, and T is the time since the initial signal. We analyze the 2 hr flare seen by ASCA 36 hr after the GRB and conclude that the surface filling factor must be small (10 -3 ) in the X-ray afterglow phase as well. Compared with the energy required for an isotropic shell, E iso , explanations for a low surface filling factor can either require more energy (f -1 E iso ∼10 56 ergs) or less energy [(ΔT/4T) 2 E iso ∼10 49 ergs]. Thus, the low filling factor cannot be used as a strong argument that GRBs must be internal shocks. copyright copyright 1999. The American Astronomical Society

Optimized control of X-ray exposure and image noise using a particular multislice CT scanner

International Nuclear Information System (INIS)

Yamamoto, Shuji; Suzuki, Masahiro; Kakinuma, Ryutaro; Moriyama, Noriyuki; Koyama, Yoshihiro; Nagasawa, Hirofumi

2008-01-01

Patient dose reduction in computed tomography (CT) always results in a trade off between radiation exposure and image quality. There are few reports that estimate the relationship between image quality and X-ray exposure in CT examinations as one optimal index. The purpose of this study was to determine the optimal parameter settings enabling a low radiation exposure without compromising image quality using a particular 4-row multislice CT (MSCT) scanner (Aquilion VZ 4-slice CT scanner, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan). Normalized dose divided by image noise for helical pitches (nDNR: normalized dose to noise ratio) were calculated in consideration of beam collimation and tube current-time product. Optimal tube current-time product was calculated using the nDNR for the helical pitches based on user-defined standards of quality of the CT image. As a result, the nDNR proved to be well-supported to decrease the patient exposure in various exposure conditions of MSCT scans; however, the dose and image noise did not show a linear relation to the helical pitch. In conclusion, nDNR can be applied to patient dose reduction while keeping an acceptable image quality using a particular 4-row MSCT scanner. (author)

Cytological evidence of chromosomal rearrangement in the second meiotic division after exposure to X-rays

Energy Technology Data Exchange (ETDEWEB)

Szemere, G. (Orvostudomanyi Egyetem, Szeged (Hungary). Orvosbiologiai Intezet)

1982-01-01

Metaphase II cells with unequal dyad-arms and obvious X/autosomal rearrangements were found after an exposure to X-rays (2 Gy) of male mice at different stages of meiosis (pachytene, diplotene and diakinesis) with a frequency of 0.2, 1.26 and 0.6%, respectively, giving a direct cytological evidence of structural chromosomal rearrangements in metaphase II cells, partly with autosomal and partly with X/autosomal partners.

Cytological evidence of chromosomal rearrangement in the second meiotic division after exposure to X-rays

International Nuclear Information System (INIS)

Szemere, G.

1982-01-01

Metaphase II cells with unequal dyad-arms and obvious X/autosomal rearrangements were found after an exposure to X-rays (2 Gy) of male mice at different stages of meiosis (pachytene, diplotene and diakinesis) with a frequency of 0.2, 1.26 and 0.6%, respectively, giving a direct cytological evidence of structural chromosomal rearrangements in metaphase II cells, partly with autosomal and partly with X/autosomal partners. (author)

X-Ray structure and biophysical properties of rabbit fibroblast growth factor 1

Energy Technology Data Exchange (ETDEWEB)

Lee, Jihun; Blaber, Sachiko I.; Irsigler, Andre; Aspinwall, Eric; Blaber, Michael; (FSU)

2010-01-14

The rabbit is an important and de facto animal model in the study of ischemic disease and angiogenic therapy. Additionally, fibroblast growth factor 1 (FGF-1) is emerging as one of the most important growth factors for novel pro-angiogenic and pro-arteriogenic therapy. However, despite its significance, the fundamental biophysical properties of rabbit FGF-1, including its X-ray structure, have never been reported. Here, the cloning, crystallization, X-ray structure and determination of the biophysical properties of rabbit FGF-1 are described. The X-ray structure shows that the amino-acid differences between human and rabbit FGF-1 are solvent-exposed and therefore potentially immunogenic, while the biophysical studies identify differences in thermostability and receptor-binding affinity that distinguish rabbit FGF-1 from human FGF-1.

Radiation exposure to patients during extracorporeal shock wave lithotripsy

International Nuclear Information System (INIS)

Van Swearingen, F.L.; McCullough, D.L.; Dyer, R.; Appel, B.

1987-01-01

Extracorporeal shock wave lithotripsy is rapidly becoming an accepted treatment of renal calculi. Since fluoroscopy is involved to image the stones it is important to know how much radiation the patient receives during this procedure. Surface radiation exposure to the patient was measured in more than 300 fluoroscopic and radiographic procedures using thermoluminescent dosimeters. Initial results showed an average skin exposure of 10.1 rad per procedure for each x-ray unit, comparing favorably with exposure rates for percutaneous nephrostolithotomy and other routine radiological procedures. Factors influencing exposure levels include stone characteristics (location, size and opacity), physician experience and number of shocks required. Suggestions are given that may result in a 50 per cent reduction of radiation exposure

Factors influencing radiation exposure during the extracorporeal shock wave lithotripsy

Energy Technology Data Exchange (ETDEWEB)

Wei Chuan Chen; Ying Huei Lee; Ming Tsun Chen; Jong Khing Huang; Luke S Chang (Division of Urology, Dept. of Surgery, National Yang-Ming Medical College and Veterans General Hospital-Taipei, Taiwan (China))

1991-01-01

A prospective evaluation of 89 consecutive sessions of extracorporeal shock wave lithotripsy (ESWL) was undertaken to try and find the best way of minimising the amount of exposure to radiation. Forty-two patients were randomly allocated to undergo ESWL treatment by experienced surgeons (group A), and 47 to undergo the treatment by inexperienced surgeons (group B). The mean calculated entrance radiation exposure was 3.01 rads (group A: 2.64 (0.97) rads, range 1.00-4.48, group B: 3.38 (0.86) rads, range 1.11-5.75). Among factors that influenced radiation exposure, the tissue: air ratio should be borne in mind and the level of skill in controlling movement of gantry was the most important in reducing the exposure to radiation. (au).

Factors influencing radiation exposure during the extracorporeal shock wave lithotripsy

International Nuclear Information System (INIS)

Wei Chuan Chen; Ying Huei Lee; Ming Tsun Chen; Jong Khing Huang; Luke S Chang

1991-01-01

A prospective evaluation of 89 consecutive sessions of extracorporeal shock wave lithotripsy (ESWL) was undertaken to try and find the best way of minimising the amount of exposure to radiation. Forty-two patients were randomly allocated to undergo ESWL treatment by experienced surgeons (group A), and 47 to undergo the treatment by inexperienced surgeons (group B). The mean calculated entrance radiation exposure was 3.01 rads (group A: 2.64 (0.97) rads, range 1.00-4.48, group B: 3.38 (0.86) rads, range 1.11-5.75). Among factors that influenced radiation exposure, the tissue: air ratio should be borne in mind and the level of skill in controlling movement of gantry was the most important in reducing the exposure to radiation. (au)

Cosmic-ray exposure ages of six chondritic Almahata Sitta fragments

Science.gov (United States)

Riebe, M. E. I.; Welten, K. C.; Meier, M. M. M.; Wieler, R.; Barth, M. I. F.; Ward, D.; Laubenstein, M.; Bischoff, A.; Caffee, M. W.; Nishiizumi, K.; Busemann, H.

2017-11-01

The Almahata Sitta strewn field is dominated by ureilites, but contains a large fraction of chondritic fragments of various types. We analyzed stable isotopes of He, Ne, Ar, Kr, and Xe, and the cosmogenic radionuclides 10Be, 26Al, and 36Cl in six chondritic Almahata Sitta fragments (EL6 breccia, EL6, EL3-5, CB, LL4/5, R-like). The cosmic-ray exposure (CRE) ages of five of the six samples have an average of 19.2 ± 3.3 Ma, close to the average of 19.5 ± 2.5 Ma for four ureilites. The cosmogenic radionuclide concentrations in the chondrites indicate a preatmospheric size consistent with Almahata Sitta. This corroborates that Almahata Sitta chondrite samples were part of the same asteroid as the ureilites. However, MS-179 has a lower CRE age of 11.0 ± 1.4 Ma. Further analysis of short-lived radionuclides in fragment MS-179 showed that it fell around the same time, and from an object of similar size as Almahata Sitta, making it almost certain that MS-179 is an Almahata Sitta fragment. Instead, its low CRE age could be due to gas loss, chemical heterogeneity that may have led to an erroneous 21Ne production-rate, or, perhaps most likely, MS-179 could represent the true 4π exposure age of Almahata Sitta (or an upper limit thereof), while all other samples analyzed so far experienced exposure on the parent body of similar lengths. Finally, MS-179 had an extraordinarily high activity of neutron-capture 36Cl, 600 dpm kg-1, the highest activity observed in any meteorite to date, related to a high abundance of the Cl-bearing mineral lawrencite.

High-speed X-ray topography

International Nuclear Information System (INIS)

Eckers, W.; Oppolzer, H.

1977-01-01

The investigation of lattice defects in semiconductor crystals by conventional X-ray diffraction topography is very time-consuming. Exposure times can be reduced by using high-intensity X-rays and X-ray image intensifiers. The described system comprises a high-power rotating-anode X-ray tube, a remote-controlled X-ray topography camera, and a television system operating with an X-ray sensing VIDICON. System performance is demonstrated with reference to exploratory examples. The exposure time for photographic plates is reduced to 1/20 and for the X-ray TV system (resolution of the order of 30 μm) to 1/100 relative to that required when using a conventional topography system. (orig.) [de

X-ray exposure dose for the gonadal gland by the examination of computerized tomography and its protection

International Nuclear Information System (INIS)

Moriuchi, Iwao; Kaiya, Hisanori; Hirata, Toshifumi; Asada, Shuichi

1978-01-01

Computerized tomography (CT) is very useful for neuroradiological examination, and so it may possibly be used for screening tests. But x-ray exposure dose by a examination of CT is considerable, especially for the male gonadal gland. This study showed that the dose from a complete CT examination of 10 - 15 scans for a male gonadal gland was about 1,800 times more than a single plain neuroradiography. But by only a 0.07 mm lead equivalent protecter, the exposure dose resulting from CT for a gonadal gland could be reduced to 0.0 mrad. (auth.)

Reparation in unicellular green algae during chronic exposure to the action of mutagenic factors. II. Restoration of single-stranded DNA breaks following exposure of Chlamydomonas reinchardii to gamma-irradiation

International Nuclear Information System (INIS)

Sergeeva, S.A.; Ptitsina, S.N.; Shevchenko, V.A.

1986-01-01

The restoration of single-stranded breaks in the DNA in different strains of unicellular green algae (chlamydomonads) during chronic exposure to the action of mutagenic factors following γ-irradiation was investigated. It was shown that the restoration of DNA breaks was most effective in the case of strain M γ/sup mt + /, which is resistant to radiation. Strains, that were sensitive to UV irradiation showed a similar order of DNA break restoration as the wild-type strain. Strain UVS-1 showed a higher level of restoration than the wild-type strain. The data indicated that chlamydomonads have different pathways of reparation, which lead to the restoration of breaks induced by γ-irradiation and UV-rays

Characterizing risk factors for pediatric lamp oil product exposures.

Science.gov (United States)

Sheikh, S; Chang, A; Kieszak, S; Law, R; Bennett, H K W; Ernst, E; Bond, G R; Spiller, H A; Schurz-Rogers, H; Chu, A; Bronstein, A C; Schier, J G

2013-11-01

Poisonings from lamp oil ingestion continue to occur worldwide among the pediatric population despite preventive measures such as restricted sale of colored and scented lamp oils. This suggests that optimal prevention practices for unintentional pediatric exposures to lamp oil have yet to be identified and/or properly implemented. To characterize demographic, health data, and potential risk factors associated with reported exposures to lamp oil by callers to poison centers (PCs) in the US and discuss their public health implications. This was a two part study in which the first part included characterizing all exposures to a lamp oil product reported to the National Poison Data System (NPDS) with regard to demographics, exposure, health, and outcome data from 1/1/2000 to 12/31/2010. Regional penetrance was calculated using NPDS data by grouping states into four regions and dividing the number of exposure calls by pediatric population per region (from the 2000 US census). Temporal analyses were performed on NPDS data by comparing number of exposures by season and around the July 4th holiday. Poisson regression was used to model the count of exposures for these analyses. In the second part of this project, in order to identify risk factors we conducted a telephone-based survey to the parents of children from five PCs in five different states. The 10 most recent lamp oil product exposure calls for each poison center were systematically selected for inclusion. Calls in which a parent or guardian witnessed a pediatric lamp oil product ingestion were eligible for inclusion. Data on demographics, exposure information, behavioral traits, and health were collected. A descriptive analysis was performed and Fisher's exact test was used to evaluate associations between variables. All analyses were conducted using SAS v9.3. Among NPDS data, 2 years was the most common patient age reported and states in the Midwestern region had the highest numbers of exposure calls compared to

The Evaluation of Conventional X-ray Exposure Parameters Including Tube Voltage and Exposure Time in Private and Governmental Hospitals of Lorestan Province, Iran

Directory of Open Access Journals (Sweden)

Mehrdad Gholami

2015-07-01

Full Text Available Introduction In radiography, dose and image quality are dependent on radiographic parameters. The problem is caused from incorrect use of radiography equipment and from the radiation exposure to patients much more than required. Therefore, the aim of this study was to implement a quality-control program to detect changes in exposure parameters, which may affect diagnosis or patient radiation dose. Materials and Methods This cross-sectional study was performed on seven stationary X-ray units in sixhospitals of Lorestan province. The measurements were performed, using a factory-calibrated Barracuda dosimeter (model: SE-43137. Results According to the results, the highest output was obtained in A Hospital (M1 device, ranging from 107×10-3 to 147×10-3 mGy/mAs. The evaluation of tube voltage accuracy showed a deviation from the standard value, which ranged between 0.81% (M1 device and 17.94% (M2 device at A Hospital. The deviation ranges at other hospitals were as follows: 0.30-27.52% in B Hospital (the highest in this study, 8.11-20.34% in C Hospital, 1.68-2.58% in D Hospital, 0.90-2.42% in E Hospital and 0.10-1.63% in F Hospital. The evaluation of exposure time accuracy showed that E, C, D and A (M2 device hospitals complied with the requirements (allowing a deviation of ±5%, whereas A (M1 device, F and B hospitals exceeded the permitted limit. Conclusion The results of this study showed that old X-ray equipments with poor or no maintenance are probably the main sources of reducing radiographic image quality and increasing patient radiation dose.

ANATOMICAL DISPOSITION OF CARPAL BONES OF GOLDEN RETRIEVER DOG BY X-RAY EXPOSURE

Directory of Open Access Journals (Sweden)

R. Mandal

2012-07-01

Full Text Available The present study was conducted to know the general disposition of bones in carpal region of experimental dogs by X-ray study with an objective that the findings will facilitate to have an in-depth knowledge about the proper positioning of the carpal bones for surgical management of fractures and different types of bone deformities in dogs. In the present study, the anatomical disposition and arrangement pattern of carpal bones playing a pivotal role in providing the structural conformity in the limbs of Golden Retriever dog has been thoroughly confirmed by Xray exposure.

Ion recombination characteristics of the MDH 10X5-6 ionisation chamber under continuous exposure

International Nuclear Information System (INIS)

Cerra, F.

1982-01-01

Volume recombination of the induced ionization in an X-ray ionization chamber is an important factor affecting the collection efficiency of the charge when such chambers are operated at atmospheric pressure. The volume recombination process is also dependent on the X-ray exposure rate. The theory for recombination in a cylindrical ionization chamber is shown to be in agreement with experimental measurements. For the MDH 10X5-6 cylindrical ionization chamber, the recombination loss is unimportant at exposure rates consistent with its intended usage. (U.K.)

Uveal melanoma in relation to ultraviolet light exposure and host factors.

Science.gov (United States)

Holly, E A; Aston, D A; Char, D H; Kristiansen, J J; Ahn, D K

1990-09-15

We conducted a case-control interview study among 1277 subjects (407 patients, 870 controls selected by using random digit dial) in 11 western United States to determine whether uveal melanoma and cutaneous melanoma shared common risk factors. After adjustment for other factors, the risk of uveal melanoma was increased for those with green, gray, or hazel eyes [relative risk (RR) = 2.5, P less than 0.001] or blue eyes (RR = 2.2, P less than 0.001) when compared to brown. A tendency to sunburn after 0.5 h midday summer sun exposure increased risk for uveal melanoma (burn with tanning RR = 1.5, P = 0.02; burn with little tanning RR = 1.8, P less than 0.001; burn with no tanning RR = 1.7, P = 0.002); as did exposure to UV or black lights (RR = 3.7, P = 0.003); and welding burn, sunburn of the eye, or snow blindness (RR = 7.2, P less than 0.001). An association with uveal melanoma was also noted with an increasing number of large nevi (P = 0.04 for trend), although the individual risk estimates were not remarkable. These data suggest that host factors and exposure to UV light are risk factors for uveal melanoma.

Patient doses due to a diagnostic X-ray picture

International Nuclear Information System (INIS)

Riet, A. van 't.

1977-09-01

The influence of technical parameters on patient doses in X-ray diagnostics has been investigated. During an X-ray picture (30 x 40 or 35 x 43 cm 2 ) for general survey in intraveneous pyelography (IVP), skin exposure measurements in the centre of the radiation beam were carried out at 650 adult female patients in 46 Dutch hospitals. In addition, the first half-value layer of the radiation was measured. In 15 of these hospitals, similar measurements were also carried out at a Rando phantom. Small LiF thermoluminescent dosemeters were used for all measurements. The results show a remarkable variation in the mean entrance- and exit-exposure per hospital. The variation in the mean entrance-exposure per hospital (factor 8) is mainly caused by differences in radiation quality. In some hospitals, no added filtration is used while others use a relatively heavy filtration. The variation in the mean exit-exposure per hospital could not be explained uniquely from technical parameters like grid, screen and film sensivity. From phantom measurements it was found that other parameters like adjustment of the automatic exposure timer and film density required by the radiographer are of importance. The measuring system used has shown to be an adequate and simple tool for a crude selection of those hospitals where skin exposures are relatively high. On the basis of the collected data some recommendations are given to promote dose reduction in X-ray diagnostics. The use of fast screen-film combinations is of great potential importance. However further investigation seems desirable, especially concerning patient dose during fluoroscopy 0

Solar proton exposure of an ICRU sphere within a complex structure part II: Ray-trace geometry.

Science.gov (United States)

Slaba, Tony C; Wilson, John W; Badavi, Francis F; Reddell, Brandon D; Bahadori, Amir A

2016-06-01

A computationally efficient 3DHZETRN code with enhanced neutron and light ion (Z ≤ 2) propagation was recently developed for complex, inhomogeneous shield geometry described by combinatorial objects. Comparisons were made between 3DHZETRN results and Monte Carlo (MC) simulations at locations within the combinatorial geometry, and it was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in ray-trace geometry. This latest extension enables the code to be used within current engineering design practices utilizing fully detailed vehicle and habitat geometries. Through convergence testing, it is shown that fidelity in an actual shield geometry can be maintained in the discrete ray-trace description by systematically increasing the number of discrete rays used. It is also shown that this fidelity is carried into transport procedures and resulting exposure quantities without sacrificing computational efficiency. Published by Elsevier Ltd.

Myeloid leukaemia frequency after protracted exposure to ionizing radiation: experimental confirmation of the flat dose-response found in ankylosing spondylitis after a single treatment course with x-rays

Energy Technology Data Exchange (ETDEWEB)

Mole, R H; Major, I R [Medical Research Council, Harwell (UK). Radiobiological Research Unit

1983-01-01

The dose-response for leukaemia induction by exposure to ionizing radiation protracted over several weeks was largely independent of dose not only in X-rayed patients with ankylosing spondylitis but also in experimentally ..gamma..-rayed CBA/H mice. In the experiment the induced leukaemia frequency of acute myeloid leukaemia was independent of a several thousand-fold variation in physical dose rate. Any difference in leukaemia induction between brief and protracted exposures must therefore depend on specifically biological consequences of protracted exposures. Experimental analysis is required to provide the guides for inference about risks of low level exposure from observations on relatively heavily irradiated populations.

Developable images produced by x-rays using the nickel-hypophosphite system. 2: Exposure and development parameters for sodium hypophosphite

Science.gov (United States)

May, C. E.; Philipp, W. H.; Marsik, S. J.

1972-01-01

Crystalline sodium hypophosphite was X-irradiated and then treated with an ammoniacal nickel hypophosphite solution. Treatment resulted in the precipitation of nickel metal. The yield of nickel metal varied directly with particle size, sample weight, X-ray voltage, target current, exposure time, and development time. These findings show the process to be potentially useful in X-ray type photography. The half-life for the latent image species was found to be relatively short; but this is not critical in most X-ray photography applications. Furthermore, the work can be interpreted on the basis that a hydrogen atom is involved in the mechanism and indicates that the autocatalytic development step may be self-poisoning.

Determination of correction and conversion factor of exposure rate generated Gamma spectrometer GR-320 to Victoreen data

International Nuclear Information System (INIS)

Supardjo-AS; Mappa, Djody-Rachim; Nasrun-Syamsul; Syamsul-Hadi

2000-01-01

Exposure rate data of Muria Peninsula were generated from Victoreen-491 measurement and calculation of radioelement content in soil which were measured by Exploranium GR-320, using IAEA formula. However those data are not be comparable so the exposure rate calculated from Gamma Spectrometer data necessarily to be corrected. The correction factor was determinate by measuring the exposure rate of at the NMDC's back yard selected location using Victoreen-491 and Gamma Spectrometer Exploranium GR-320 . Correction factor was created by comparing mean exposure rate data that calculated from 30 data measured by Gamma Spectrometer instrument and to those Victoreen's exposure rate. Conversion factor was gained from comparing of total count data of Gamma Spectrometer Exploranium GR-320 to Victoreen's exposure rate data. The correction factor of Exploranium GR-320's exposure rate is 0.34 μR/hours, and the conversion factor of total count is 0.0092 μR/hours per c/m. Deviation Victoreen 491 = 4.7 % and Gamma Spectrometer Exploranium GR-320 8.6 %

Concept of malignant significant factor and its applicability for and occupational exposures

International Nuclear Information System (INIS)

Hashizume, Tadashi; Maruyama, Takashi; Tateno, Yukio

1980-01-01

In the medical and occupational exposures, there is a tradition to use the genetically significant dose as an index of harm to the population although it only includes the genetical effects from ionizing radiations. A similar significant dose for somatic effects such as radiation leukemogenesis and carcinogenesis should be added to the genetically significant dose in order to approach an index of total harm to the population from medical and occupational exposures. For this purpose, leukemia and malignant significant factors were determined based on the induction of malignant diseases including leukemia for the atomic bombs in Hiroshima and Nagasaki and the life expectancy of individuals subject to medical examinations or treatments as well as radiation workers, taking account of the possibility of their deaths due to other diseases or accidents during a latent period of malignant diseases. The resultant significant factors were tabulated as a function of life expectancy for their application to medical and occupational exposures. For an example, the malignant significant factor for a person having the life expectancy of 60, 40 and 20 years was about 0.87, 0.45 and 0.10, respectively. This paper will discuss the applicability of the leukemia and malignant significant factors to the risk estimation of medical and occupational exposures; namely (1) the risk estimation for an individual in the population; (2) the risk estimation for individuals in a given age group who were continuously irradiated with natural radiations or received occupational exposures; (3) the risk estimation for the pupulation in a given age distribution and (4) the risk estimation for individuals after retirement of radiation works. (author)

Stochastic risk estimation from medical x-ray diagnostic examinations, 3

International Nuclear Information System (INIS)

Hashizume, Tadashi; Maruyama, Takashi; Noda, Yutaka; Iwai, Kazuo; Fukuhisa, Kenjiro

1981-01-01

The genetically significant dose (GSD), per Caput mean bone marrow dose (CMD), leukemia significant dose (LSD) and malignancy significant dose (MSD) from medical diagnostic X-ray examinations in Japan were estimated based on a 1979 nationwide survey of randomly sampled hospitals and clinics. The population risk estimates were carried out using the resultant values of GSD, LSD and MSD. In the risk estimates, the significant factors, namely, the relative child expectancy, the leukemia significant factor and the malignancy significant factor, for patients were assumed to be same as those of general population. The risk factors used were 185 x 10 -6 rad -1 for genetic risk of all generations, 20 x 10 -6 rad -1 for fatal leukemia and 165 x 10 -6 rad -1 for fatal malignant diseases, respectively. The resultant annual population doses per person were 15 mrad (0.15 mGy) for GSD, 107 mrad (1.07 mGy) for CMD, 86 mrad (0.86 mGy) for LSD and 43 mrad (0.43 mGy) for MSD, respectively. The present data other than the MSD were compared with the data in 1960, 1969 and 1974. For example, the GSD of 1979 was approximately same as that of 1974, although the annual number of examinations in 1979 increased by about 30 percent as compared with those of 1974. The population risks from X-ray diagnosis were estimated to be 260 persons per year for genetic risk of all generations, 192 person per year for fatal leukemic risk and 825 person per year for malignant risk, respectively, for the whole population in Japan, assuming that the X-ray diagnosis in 1979 will be performed continuously in the future. The average risks per one exposure for X-ray radiography were estimated using the weighted average of the significant factor and the organ or tissue dose with the number of radiographic exposures by age and by type of examination. The average risks per radiographic exposure were 176 x 10 -9 for genetic risk, 285 x 10 -9 for leukemic risk and 1.75 x 10 -6 for malignant risk respectively. (author)

Determining optimum wavelength of ultraviolet rays to pre-exposure of non-uniformity error correction in Gafchromic EBT2 films

Science.gov (United States)

Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Noguchi, Atsushi; Yabunaka, Kouichi

2018-03-01

Gafchromic films have been used to measure X-ray doses in diagnostic radiology such as computed tomography. The double-exposure technique is used to correct non-uniformity error of Gafchromic EBT2 films. Because of the heel effect of diagnostic x-rays, ultraviolet A (UV-A) is intended to be used as a substitute for x-rays. When using a UV-A light-emitting diode (LED), it is necessary to determine the effective optimal UV wavelength for the active layer of Gafchromic EBT2 films. This study evaluated the relation between the increase in color density of Gafchromic EBT2 films and the UV wavelengths. First, to correct non-uniformity, a Gafchromic EBT2 film was pre-irradiated using uniform UV-A radiation for 60 min from a 72-cm distance. Second, the film was irradiated using a UV-LED with a wavelength of 353-410 nm for 60 min from a 5.3-cm distance. The maximum, minimum, and mean ± standard deviation (SD) of pixel values of the subtraction images were evaluated using 0.5 inches of a circular region of interest (ROI). The highest mean ± SD (8915.25 ± 608.86) of the pixel value was obtained at a wavelength of 375 nm. The results indicated that 375 nm is the most effective and sensitive wavelength of UV-A for Gafchromic EBT2 films and that UV-A can be used as a substitute for x-rays in the double-exposure technique.

Stochastic risk estimation from medical x-ray diagnostic examinations, 2. Risk estimates of individuals from x-ray diagnosis

Energy Technology Data Exchange (ETDEWEB)

Hashizume, T; Maruyama, T; Noda, Y; Iwai, K; Tateno, Y [National Inst. of Radiological Sciences, Chiba (Japan); Nishizawa, K

1981-01-01

The risks of genetic, leukemia and malignant diseases from medical X-ray diagnostic examinations were estimated using the frequency of radiographic and fluoroscopic exposures per diagnostic examination, child expectancy, leukemia and malignancy significant factors, and using a weighting factor determined on the basis of data concerning the cancer mortality among atomic bomb survivors in Nagasaki and of a recommendation of International Commission of Radiological Protection. The organ or tissue doses with respect to the stochastic risks were determined with ionization chambers and thermoluminescent dosimeters placed at the positions of the organs or tissues in a RANDO woman phantom which was exposed to diagnostic X-rays according to technical factors of typical radiographic and fluoroscopic examinations obtained from a nationwide survey. The resultant risks by age-group and type of radiographic and fluoroscopic examination are tabulated in terms of risk level of 10/sup -6/. In general, the total risk defined as the sum of genetic, leukemia and malignant risks was a high value for the X-ray diagnosis of digestive organs involving barium meal and barium enema. For example, the total risk for young age-group was 100 to 200 x 10/sup -6/ for the X-ray diagnosis of digestive organs. The total risk from the chest radiography was lower value as compared with the risk from the X-ray diagnosis of other organs or tissues. On the contrary, the risk from the chest tomography was comparable to the risk from the diagnosis of digestive organs. The total risk decreased with increasing of age for every X-ray diagnostic examination.

Effective high voltage at X-ray tube in hard X-ray chest imaging

International Nuclear Information System (INIS)

Klein, J.

1987-01-01

The FRG standard TGL 36 661 (March 1980) for synoptical chest pictures of large size in adults specifies the 120 kV voltage at the X-ray tube together with maximal, 100% use of the capacity of the tube (hard picture, short exposure time). By means of circular recording and by measuring the high voltage at the X-ray tube it was quantitatively shown that the effective voltage during exposure is (according to the exposure time and the attenuation phase of the generator) always lower than the set-up voltage of 120 kV. This phenomenon is the more marked the shorter the actual exposure time in comparison with the attenuation phase of the generator. The typical characteristic of a hard X-ray chest picture is thus not given only by the setting-up of voltage. The impact of the reduction in voltage is thus quantitatively shown also from the aspect of the radiation burden for the patient. (author). 7 figs., 8 refs

X-ray - skeleton

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this ... Degenerative bone conditions Osteomyelitis Risks There is low radiation exposure. X-rays machines are set to provide the smallest ...

Extremity x-ray

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003461.htm Extremity x-ray To use the sharing features on this page, ... in the body Risks There is low-level radiation exposure. X-rays are monitored and regulated to provide the ...

Quality control assessment of diagnostic X-ray facilities in Ghana ...

African Journals Online (AJOL)

Twenty-three X-ray machines located at 20 different hospitals in Ghana were assessed for quality assurance and control. The radiographic parameters evaluated were tube voltage and current, tube output consistency variation with kilovoltage (kV) and current-time (mAs) factor, exposure time accuracy and beam quality as ...

Seasonal correction factors in radon exposure assessment: are they help or hindrance?

International Nuclear Information System (INIS)

Denman, A.R.; Groves-Kirkby, C.J.; Phillips, P.S.; Woolridge, A.C.; Crockett, R.G.M.

2008-01-01

Northern Hemisphere radon levels are generally higher in Winter than in Summer, primarily due to the increased interior/exterior temperature difference during the heating season, which results in greater atmospheric pressure differential and enhanced radon ingress. Following a survey of domestic radon levels in the United Kingdom (UK), the former National Radiological Protection Board (NRPB) established measurement protocols and promulgated nationally-applicable Seasonal Correction Factors (SCF). These factors convert a one-month or three-month radon concentration measurement, commencing in any month of the year, to an annual mean radon concentration. Subsequent study suggests that this approach may not be sufficiently sensitive to local conditions, and a major independent investigation reported seasonal correction factors specific to nine geographic regions, together with a composite set applicable to all regions. Similar geographical variability has been observed in other countries. In a recent evaluation of the applicability of short-term exposures in quantifying long-term domestic radon levels, radon levels in 34 houses were monitored over a 12-month period with 1-week, 1-month and 3-month exposures. Radon concentration variation departed significantly from that expected on the basis of the recommended SCFs, with year-end discontinuities at all exposure durations. Weekly monitoring with electrets was continued in three of these locations for four years. Short-term variations in radon levels were observed, particularly during the shorter exposures, and this dataset has also shown year-on-year variations. Overall, SCFs derived from this dataset are significantly lower than those recommended, but are comparable with other results from the UK and elsewhere, particularly those that recognise geological diversity and are consequently prepared on a regional rather than a national basis. These findings call into question the validity of using nationally

Association of brain cancer with dental x-rays and occupation in Missouri

International Nuclear Information System (INIS)

Neuberger, J.S.; Brownson, R.C.; Morantz, R.A.; Chin, T.D.

1991-01-01

This investigation of a brain cancer cluster in Missouri used two approaches to investigate associations with potential risk factors. In a case-control study in a rural town, we interviewed surrogates of cases and controls about potential risk factors. We found a statistically significant positive association of brain cancer with reported exposure to dental x-rays. Occupation was not associated with the cluster in the rural town. In a standardized proportional mortality study for the state of Missouri, we calculated the observed and expected proportion of brain cancers by occupation and industry in Missouri decedents. We found that motor vehicle manufacturers, beauty shop workers, managers and administrators, elementary school teachers, and hairdressers and cosmetologists had significantly elevated proportions of brain cancer. Brain tumors are inconsistently associated with occupation in the literature. Further study of brain cancer etiology with respect to dental x-ray exposures seems warranted

Isotopic Evidence for Multi-stage Cosmic-ray Exposure Histories of Lunar Meteorites: Long Residence on the Moon and Short Transition to the Earth

International Nuclear Information System (INIS)

Hidaka, Hiroshi; Sakuma, Keisuke; Nishiizumi, Kunihiko; Yoneda, Shigekazu

2017-01-01

It is known that most lunar meteorites have complicated cosmic-ray exposure experiences on the Moon and in space. In this study, cosmic-ray irradiation histories of six lunar meteorites, Dhofar 489, Northwest Africa 032 (NWA 032), NWA 479, NWA 482, NWA 2995, and NWA 5000, were characterized from neutron-captured isotopic shifts of Sm and Gd, and from the abundances of long-lived cosmogenic radionuclides like 10 Be, 26 Al, 36 Cl, and 41 Ca. Sm and Gd isotopic data of all of six meteorites show significant isotopic shifts of 149 Sm– 150 Sm and 157 Gd– 158 Gd caused by accumulation of neutron capture reactions due to cosmic-ray irradiation, corresponding to the neutron fluences of (1.3–9.6) × 10 16 n cm −2 . In particular, very large Sm and Gd isotopic shifts of NWA 482 are over those of a lunar regolith 70002, having the largest isotopic shifts among the Apollo regolith samples, corresponding to cosmic-ray exposure duration over 800 million years in the lunar surface (2 π irradiation). Meanwhile, the concentrations of cosmogenic radionuclides for individual six meteorites show the short irradiation time less than one million years as their bodies in space (4 π irradiation). Our data also support the results of previous studies, revealing that most of lunar meteorites have long exposure ages at shallow depths on the Moon and short transit times from the Moon to the Earth.

Indoor Air Pollutant Exposure for Life Cycle Assessment: Regional Health Impact Factors for Households

DEFF Research Database (Denmark)

Rosenbaum, Ralph K.; Meijer, Arjen; Demou, Evangelia

2015-01-01

of magnitude, due to the variability of ventilation rate, building occupation, and volume. To compare health impacts as a result of indoor exposure with those from outdoor exposure, the indoor exposure characterization factors determined with the modified USEtox model were applied in a case study on cooking...

Cosmic ray production curves below reworking zones

International Nuclear Information System (INIS)

Blanford, G.E.

1980-01-01

A method is presented for calculating cosmic ray production profiles below reworking zones. The method uses an input reworking depth determined from data such as signatures in the depth profile of ferromagnetic resonance intensity and input cosmic ray production profiles for an undisturbed surface. Reworking histories are simulated using Monte Carlo techniques, and depth profiles are used to determine cosmic ray exposure age limits with a specified probability. It is shown that the track density profiles predict cosmic ray exposure ages in lunar cores that are consistent with values determined by other methods. Results applied to neutron fluence and spallation rare gases eliminate the use of reworking depth as an adjustable parameter and give cosmic ray exposure ages that are compatible with each other

Measuring lifetime stress exposure and protective factors in life course research on racial inequality and birth outcomes.

Science.gov (United States)

Malat, Jennifer; Jacquez, Farrah; Slavich, George M

2017-07-01

There has been a long-standing interest in better understanding how social factors contribute to racial disparities in health, including birth outcomes. A recent emphasis in this context has been on identifying the effects of stress exposure and protective factors experienced over the entire lifetime. Yet despite repeated calls for a life course approach to research on this topic, very few studies have actually assessed how stressors and protective factors occurring over women's lives relate to birth outcomes. We discuss this issue here by describing how challenges in the measurement of lifetime stress exposure and protective factors have prevented researchers from developing an empirically-based life course perspective on health. First, we summarize prevailing views on racial inequality and birth outcomes; second, we discuss measurement challenges that exist in this context; and finally, we describe both new tools and needed tools for assessing lifetime stress exposure and suggest opportunities for integrating information on stress exposure and psychosocial protective factors. We conclude that more studies are needed that integrate information about lifetime stress exposures and the protective factors that promote resilience against such exposures to inform policy and practice recommendations to reduce racial disparities in birth outcomes.

New intraoral x-ray fluorographic imaging for dentistry

International Nuclear Information System (INIS)

Higashi, T.; Osada, T.; Aoyama, W.; Iguchi, M.; Suzuki, S.; Kanno, M.; Moriya, K.; Yoshimura, M.; Tusuda, M.

1983-01-01

A new dental x-ray fluorographic unit has been developed. This unit is composed of small intraoral x-ray tube, a compact x-ray image intensifier, and a high-resolution TV system. The purposes for developing this equipment were to (1) directly observe the tooth during endodontic procedures and (2) reduce x-ray exposure to the patient and the dentist. The radiation exposure can be reduced to about 1/600 the exposure used with conventional dental film. In clinical trials, a satisfactory fluorographic dental image for endodontic treatment was obtained with this new device

Radiation exposure and management of medical employes

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, C [Nagoya Univ. (Japan)

1981-11-01

Medical employes handling medical radiation are increasing in recent years. In connection with the radiation exposure management, it was surveyed how much their cumulative exposure doses are and how many employes distribute in respective exposure levels. The medical employes surveyed are physicians, radiation technicians and nurses, working in the hospitals of educational institutions. The period of survey is every three years, from 1962 to 1977. For X-ray and ..gamma..-ray, respectively, the yearly cumulative exposure doses were measured by film badges, stepwise starting from below 500 mrem upward to over 5000 mrem; for the respective groups of employes, the percentage in each dose level was shown. The percentage in the level below 500 mrem was the largest in all groups, and in both X-ray and ..gamma..-ray, the percentages in higher levels decreased sharply to less than 7%. The exposure management has been improved in recent years.

Preliminary results of an attempt to predict over apron occupational exposure of cardiologists from cardiac fluoroscopy procedures based on DAP (dose area product) values.

Science.gov (United States)

Toossi, Mohammad Taghi Bahreyni; Mehrpouyan, Mohammad; Nademi, Hossein; Fardid, Reza

2015-03-01

This study is an effort to propose a mathematical relation between the occupational exposure measured by a dosimeter worn on a lead apron in the chest region of a cardiologist and the dose area product (DAP) recorded by a meter attached to the X-ray tube. We aimed to determine factors by which DAP values attributed to patient exposure could be converted to the over-apron entrance surface air kerma incurred by cardiologists during an angiographic procedure. A Rando phantom representing a patient was exposed by an X-ray tube from 77 pre-defined directions. DAP value for each exposure angle was recorded. Cardiologist exposure was measured by a Radcal ionization chamber 10X5-180 positioned on a second phantom representing the physician. The exposure conversion factor was determined as the quotient of over apron exposure by DAP value. To verify the validity of this method, the over-apron exposure of a cardiologist was measured using the ionization chamber while performing coronary angiography procedures on 45 patients weighing on average 75 ± 5 kg. DAP values for the corresponding procedures were also obtained. Conversion factors obtained from phantom exposure were applied to the patient DAP values to calculate physician exposure. Mathematical analysis of our results leads us to conclude that a linear relationship exists between two sets of data: (a) cardiologist exposure measured directly by Radcal & DAP values recorded by the X-ray machine system (R (2) = 0.88), (b) specialist measured and estimated exposure derived from DAP values (R (2) = 0.91). The results demonstrate that cardiologist occupational exposure can be derived from patient data accurately.

Radiation and chemically induced potentially lethal lesions in noncycling mammalian cells: recovery analysis in terms of x-ray- and ultraviolet-like-systems

International Nuclear Information System (INIS)

Hahn, G.M.

1975-01-01

Recovery from and fixation of potentially lethal damage after exposure of Chinese hamster cells to uv and to x irradiation were investigated, as was recovery after exposure to chemotherapeutic agents. Recovery after uv radiation has a T/sub 1 / 2 / of about 20 hr; the fraction of cells able to undergo recovery depends upon nutritional factors both before and after exposure. After x irradiation, recovery proceeds with a T/sub 1 / 2 / of approximately 2 hr and is much less influenced by nutritional factors. Fixation after serum stimulation has a T/sub 1 / 2 / of 3 to 4 hr in uv-irradiated cells, a T/sub 1 / 2 / of 30 min in x-irradiated cells. Recovery kinetics after nitrogen mustard and bleomycin exposures mimic those for x-ray exposure; after methyl methane sulfonate the kinetics are mainly uv-like, though with an x-ray-like component. Recovery by cells with BUdR-substituted DNA and irradiated with visible light is primarily x-ray-like, though with a uv-like component. There is no recovery by cells exposed to adriamycin or to 1,3-bis(2-chloroethyl)-1-nitrosourea

Radiation exposure of the UK population from medical and dental x-ray examinations

International Nuclear Information System (INIS)

Hart, D.; Wall, B.F.

2002-03-01

Knowledge of recent trends in the radiation doses from x-ray examinations and their distribution for the UK population provides useful guidance on where best to concentrate efforts on patient dose reduction in order to optimise the protection of the population in a cost-effective manner. In this report, the results of a recent survey of the frequency of medical and dental x-ray examinations in the UK and contemporary data on the radiation doses typically received by patients, are used to assess trends in the extent and the pattern of the population exposure. Individual patient doses, expressed in terms of the effective dose, range from a few microsieverts for simple radiographic examinations of the teeth, limbs or chest to tens of millisieverts for prolonged fluoroscopic procedures or some computed tomography (CT) examinations. A total of about 41.5 million medical and dental x-ray examinations are now conducted each year in the UK (0.70 examination per head of population) resulting in an annual per caput effective dose of 330 μSv. This is not significantly different from the previous rough estimate of 350 μSv for 1991. However, over the last ten years CT has more than doubled its contribution and is now responsible for 40% of the total dose to the population from medical x-rays. In contrast, the contribution from conventional radiographic and fluoroscopic examinations has nearly halved to about 44%. Interventional and angiographic procedures together contribute the remaining 16%. The annual per caput dose of 330 μSv is low in comparison with other countries having similarly developed systems of health care. This is due to both a lower frequency of x-ray examinations per head of population and generally lower doses in the UK than in other developed countries. However, the much increased contributions of CT, angiography and interventional procedures to the UK population dose indicate an urgent need to develop radiation protection and optimisation activities for

Exposure of the Spanish population to radiation from natural sources

International Nuclear Information System (INIS)

Garcia-Talavera, M.; Suarez, E.; Matarranz, J.L.; Salas, R.; Ramos, L.

2006-01-01

We have assessed the exposure of the Spanish population to natural radiation sources. The annual average effective dose is estimated to be 2.38 mSv, taking into account contributions from cosmic radiation (13.8%), terrestrial gamma radiation (39%), radon and thoron inhalation (34%) and ingestion (13.2%). Cosmic radiation doses were calculated from town altitude data. Terrestrial gamma ray exposure outdoors was derived from the M.A.R.N.A. (natural gamma radiation map of Spain). Indoor gamma ray exposure was calculated by multiplying the corresponding outdoor value by a conversion factor, which was obtained by a linear least-squares fit of experimental measurements. Radon doses were estimated from national surveys carried out throughout the country. To assess doses by ingestion of water and foodstuffs we considered the results from a detailed study on consumption habits by age and geographical area in Spain, promoted by C.S.N., and average radioactivity values from UNSCEAR. (authors)

Exposure of the Spanish population to radiation from natural sources

Energy Technology Data Exchange (ETDEWEB)

Garcia-Talavera, M.; Suarez, E.; Matarranz, J.L.; Salas, R.; Ramos, L. [Consejo de Seguridad Nuclear. Justo Dorado, Madrid (Spain)

2006-07-01

We have assessed the exposure of the Spanish population to natural radiation sources. The annual average effective dose is estimated to be 2.38 mSv, taking into account contributions from cosmic radiation (13.8%), terrestrial gamma radiation (39%), radon and thoron inhalation (34%) and ingestion (13.2%). Cosmic radiation doses were calculated from town altitude data. Terrestrial gamma ray exposure outdoors was derived from the M.A.R.N.A. (natural gamma radiation map of Spain). Indoor gamma ray exposure was calculated by multiplying the corresponding outdoor value conversion factor, which was obtained by a linear least-squares fit of experimental measurements. Radon doses were estimated from national surveys carried out throughout the country. To assess doses by ingestion of water and foodstuffs we considered the results from a detailed study on consumption habits by age and geographical area in Spain, promoted by C.S.N., and average radioactivity values from UNSCEAR. (authors)

The selection of occupancy factors

International Nuclear Information System (INIS)

Lakey, J.R.A.

1977-01-01

An estimate of the proportion of time that an area is occupied by radiation workers is often used in radiological protection to permit relaxation of exposure rate limits above those for continuous occupation. This proportion is known as an occupancy factor and is used most frequently in X-ray facilities. The strategy for controlling the external exposure of radiation workers must be decided before occupancy factors are selected for the design of the radiation protection facilities. When shielding has to be designed the occupancy factor effects the design objectives and permits increased exposure rates at the shield surface. It is useful to note that the selection of occupancy factors with due regard to the expected spatial variation of the exposure rate can help to reduce the range of the worker's radiation exposure because field gradients are usually steeper close to the shield. When other hazards, such as internal exposure, and other constraints, such as cost of the space consumed, are added, the selection of the optimum set of occupancy factors is more difficult. Two zone occupancy factors are discussed in this paper and proposals are made for a strategy to be used when there is more than one hazard and the designer has to meet constraints imposed by limitations of the facilities available. An important feature of the strategy is the avoidance of high radiation exposure to small groups of workers. The errors involved in assessment of the actual dose received by the radiation worker must be taken into account and in particular the selection of the higher exposure rate limits must be made with attention to the accident potential

Risk factors for tube exposure as a late complication of glaucoma drainage implant surgery

Directory of Open Access Journals (Sweden)

Chaku M

2016-03-01

Full Text Available Meenakshi Chaku,1 Peter A Netland,2 Kyoko Ishida,3 Douglas J Rhee4 1Department of Ophthalmology, Loyola University Chicago, Maywood, IL, 2Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA; 3Department of Ophthalmology, Toho University, Tokyo, Japan; 4Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, USA Purpose: The purpose of this study was to evaluate the risk factors for tube exposure after glaucoma drainage implant surgery.Patients and methods: This was a retrospective case-controlled observational study of 64 eyes from 64 patients. Thirty-two eyes of 32 patients with tube erosion requiring surgical revision were compared with 32 matched control eyes of 32 patients. Univariate and multivariate risk factor analyses were performed.Results: Mean age was significantly younger in the tube exposure group compared with the control group (48.2±28.1 years versus 67.3±18.0 years, respectively; P=0.003. The proportion of diabetic patients (12.5% in the tube exposure group was significantly less (P=0.041 compared with the control group (37.5%. Comparisons of the type and position of the drainage implant were not significantly different between the two groups. The average time to tube exposure was 17.2±18.0 months after implantation of the drainage device. In both univariate and multivariate analyses, younger age (P=0.005 and P=0.027 and inflammation prior to tube exposure (P≤0.001 and P=0.004 were significant risk factors. Diabetes was a significant risk factor only in the univariate analysis (P=0.027.Conclusion: Younger age and inflammation were significant risk factors for tube exposure after drainage implant surgery. Keywords: glaucoma drainage implant complications, Ahmed Glaucoma Valve, Baerveldt implant, tube erosion, pericardial patch graft

On the determination of the water energy dose for X-rays produced with high voltages up to 100 kV

International Nuclear Information System (INIS)

Engelke, B.A.; Grosswendt, B.

1989-01-01

For X-rays produced with high-tensions up to 100 kV the absorbed dose to water in water can be determined by measuring the exposure or air kerma and by means of the calibration factor of the dosemeter for these quantities and a conversion factor and a correction factor. For this procedure it is necessary that the exposure or air kerma measured and the correction factor are referred to the same diameter of the X-ray beam and the same measuring distance as used for the determination of the calibration factor. If they do not agree, an additional correction factor for the influence of this discrepancy in the measuring geometry is needed. The paper gives the values of this correction factor. Furthermore, it informs on new values of the backscattering factor in water and of the correction k a→w required for the determination of the absorbed dose to water in water. (orig.) [de

Radiation exposure and management of medical employes

International Nuclear Information System (INIS)

Yamamoto, Chiaki

1981-01-01

Medical employes handling medical radiation are increasing in recent years. In connection with the radiation exposure management, it was surveyed how much their cumulative exposure doses are and how many employes distribute in respective exposure levels. The medical employes surveyed are physicians, radiation technicians and nurses, working in the hospitals of educational institutions. The period of survey is every three years, from 1962 to 1977. For X-ray and ν-ray, respectively, the yearly cumulative exposure doses were measured by film badges, stepwise starting from below 500 mrem upward to over 5000 mrem; for the respective groups of employes, the percentage in each dose level was shown. The percentage in the level below 500 mrem was the largest in all groups, and in both X-ray and ν-ray, the percentages in higher levels decreased sharply to less than 7%. The exposure management has been improved in recent years. (J.P.N.)

Buildup factor and mechanical properties of high-density cement mixed with crumb rubber and prompt gamma ray study

Science.gov (United States)

Aim-O, P.; Wongsawaeng, D.; Tancharakorn, S.; Sophon, M.

2017-09-01

High-density cement mixed with crumb rubber has been studied to be a gamma ray and neutron shielding material, especially for photonuclear reactions that may occur from accelerators where both types of radiation exist. The Buildup factors from gamma ray scattering, prompt and secondary gamma ray emissions from neutron capture and mechanical properties were evaluated. For buildup factor studies, two different geometries were used: narrow beam and broad beam. Prompt Gamma Neutron Activation Analysis (PGNAA) was carried out to determine the prompt and secondary gamma ray emissions. The compressive strength of samples was evaluated by using compression testing machine which was central point loading crushing test. The results revealed that addition of crumb rubber increased the buildup factor. Gamma ray spectra following PGNAA revealed no prompt or secondary gamma ray emission. Mechanical testing indicated that the compressive strength of the shielding material decreased with increasing volume percentage of crumb rubber.

Disorders of oxidation homeostasis in the blood and organs of rats under the influence of external x-ray exposure

International Nuclear Information System (INIS)

Uzlenkova, N.Je.

2009-01-01

The study was performed in the blood and organs (lungs and skin) of male rats weighing 160-180 g. Single external x-ray exposure to minimal and medial lethal doses causes stable disorders in oxidation homeostasis resulting in peroxidation state and development of chronic oxidative stress in the organism of the exposed rats.

Occupational exposure and risks associated with the X-ray and gamma ray scanners used for destination inspection at the port of Tema, Ghana

International Nuclear Information System (INIS)

Gbormittah, S.V.

2010-01-01

The x-ray linear accelerator scanner with average energy of 5 MeV operated by the Gateway Services Limited (GSL) and the Cobalt-60 gamma ray scanner with average energy of 1.25 MeV operated by the Ghana Customs Inspection Company Limited (GCIC) have been in use for destination inspection at the Port of Tema for the past ten (10) and six (6) years respectively. For radiation protection purposes, there is the need to assess the risk of exposure to ensure that Staff are not unduly overexposed to minimize the likelihood of adverse radiation effects. The prime objective of this research was to compare the risks from exposure, working conditions and safety culture of the two facilities in order to determine the facility that gives higher levels of exposure to the workers. Data was collected by means of questionnaires and measurements at the two facilities for a period of eight (8) weeks. Personal monitoring data for the occupationally exposed workers of the two facilities for a period sixty-one (61) months were obtained from the Personal Monitoring Laboratory of the Radiation Protection Board; these data were used for mean annual dose, mean annual collective dose and risks assessments for Staff of the two facilities. Ambient dose measurements were carried out with a calibrated Thermo Electron Micro Sievert Doserate survey meter and LiF TLD-100 dosimeters at selected points in the two facilities were 1.16 mSv/a and 1.41 mSv/a respectively. The mean annual effective doses estimated for the collective doses were 8.1man-Sv and 21.15 man-Sv for Staff of GSL and GCIC respectively. Assessment of risks using the ICRP 103 and 60 risk assessment models indicated that Staff of GSL and GCIC had a 0.14% and 0.17% risk of developing fatal cancer respectively. Staff of GSL had a 0.02% risk of passing on adverse hereditary traits to offsprings born after exposure while Staff of GCIC had a hereditary risk of 0.03% of passing on adverse hereditary traits to offsprings born after exposure

Computerized x-ray dose-monitoring system

International Nuclear Information System (INIS)

Hummel, R.H.; Wesenberg, R.L.; Amundson, G.M.

1985-01-01

An x-ray dose-monitoring system using a small digital computer is described. Initially, and for every 6 months afterward, the system is calibrated using an exposure meter. For each exposure, the computer receives values of x-ray technique and beam geometry from the x-ray generator through a specially designed electronic interface. Then, by means of calibration data, entrance exposure, area exposure product, and integral dose are obtained and printed for each patient examined. The overall accuracy of the system is better than +/-20%. Operation is semiautomatic, requiring minimum operator intervention. Over 2000 patients have been monitored with the device. Because the system is computer-based, it offers the opportunity for statistical analysis of the data base created, as the results for each patient are stored on computer disk

Toddler exposure to flame retardant chemicals: Magnitude, health concern and potential risk- or protective factors of exposure: Observational studies summarized in a systematic review.

Science.gov (United States)

Sugeng, Eva J; de Cock, Marijke; Schoonmade, Linda J; van de Bor, Margot

2017-10-01

Endocrine disrupting flame retardant (FR) chemicals form a human health concern, that is investigated mostly from the perspective of adult- and early life exposure. No overview of studies on toddler exposure and health effects exist. However, toddlerhood is a critical developmental period and toddlers are at increased risk for exposure because of their age-specific behavior. This systematic review encompasses toddler FR exposure studies in three countries, associated health effects and potential environmental, demographic, or behavioral risk- or protective factors for toddler exposure. A systematic literature search in four databases (PubMed, Embase.com, The Cochrane Library (via Wiley) and Web of Science Core collection) resulted in the identification of ten publications representing seven unique studies that measured brominated and/or phosphorylated FRs in toddlers' (8-24 month-old) serum, urine, hand wipes and feces. This review showed that toddlers are exposed to a range of FRs, that thyroid hormone disruption is associated with FR exposure and that factors in the indoor environment, including products such as plastic toys, might increase FR exposure. Considering the limited amount of studies, and the variety of biological matrices, FRs, and risk- and protective factors, this review did not reveal a uniform pattern of toddler exposure across the different cohorts studied. More evidence is necessary and considering the feasibility of invasive sampling in young children, we suggest to emphasize research on non-invasive matrices. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

X-ray equipment for dental diagnostics with a dose-rate controller influencing the exposure voltage

International Nuclear Information System (INIS)

Franke, K.

1980-01-01

If a synoptic picture is taken of teeth or jaw the X-ray tube and the film carrier with the film and a radiation detector are moving around the patient's head. The detector signal is connected to the input of the actual value of the dose-rate controller containing a scanning and stop circuit with a storing time roughly corresponding to the exposure of three teeth. After the shot the actual value of the dose rate is adjusted to the desired value, thus a constant quality of the following pictures being achieved. (RW) [de

Prevalence of hazardous exposures in veterinary practice

Energy Technology Data Exchange (ETDEWEB)

Wiggins, P.; Schenker, M.B.; Green, R.; Samuels, S.

1989-01-01

All female graduates of a major U.S. veterinary school were surveyed by mailed questionnaire to obtain details of work practice and hazard exposure during the most recent year worked and during all pregnancies. Exposure questions were based on previously implicated occupational hazards which included anesthetic gases, radiation, zoonoses, prostaglandins, vaccines, physical trauma, and pesticides. The response rate was 86% (462/537). We found that practice type and pregnancy status were major determinants of hazard exposure within the veterinary profession. Small-animal practitioners reported the highest rates of exposure to anesthetic gas (94%), X-ray (90%), and pesticides (57%). Large-animal practitioners reported greater rates of trauma (64%) and potential exposure to prostaglandins (92%), Brucella abortus vaccine (23%), and carbon monoxide (18%). Potentially hazardous workplace practices or equipment were common. Forty-one percent of respondents who reported taking X-rays did not wear film badges, and 76% reported physically restraining animals for X-ray procedures. Twenty-seven percent of the respondents exposed to anesthetic gases worked at facilities which did not have waste anesthetic gas scavenging systems. Women who worked as veterinarians during a pregnancy attempted to reduce exposures to X-rays, insecticides, and other potentially hazardous exposures. Some potentially hazardous workplace exposures are common in veterinary practice, and measures to educate workers and to reduce these exposures should not await demonstration of adverse health effects.

Prevalence of hazardous exposures in veterinary practice

International Nuclear Information System (INIS)

Wiggins, P.; Schenker, M.B.; Green, R.; Samuels, S.

1989-01-01

All female graduates of a major U.S. veterinary school were surveyed by mailed questionnaire to obtain details of work practice and hazard exposure during the most recent year worked and during all pregnancies. Exposure questions were based on previously implicated occupational hazards which included anesthetic gases, radiation, zoonoses, prostaglandins, vaccines, physical trauma, and pesticides. The response rate was 86% (462/537). We found that practice type and pregnancy status were major determinants of hazard exposure within the veterinary profession. Small-animal practitioners reported the highest rates of exposure to anesthetic gas (94%), X-ray (90%), and pesticides (57%). Large-animal practitioners reported greater rates of trauma (64%) and potential exposure to prostaglandins (92%), Brucella abortus vaccine (23%), and carbon monoxide (18%). Potentially hazardous workplace practices or equipment were common. Forty-one percent of respondents who reported taking X-rays did not wear film badges, and 76% reported physically restraining animals for X-ray procedures. Twenty-seven percent of the respondents exposed to anesthetic gases worked at facilities which did not have waste anesthetic gas scavenging systems. Women who worked as veterinarians during a pregnancy attempted to reduce exposures to X-rays, insecticides, and other potentially hazardous exposures. Some potentially hazardous workplace exposures are common in veterinary practice, and measures to educate workers and to reduce these exposures should not await demonstration of adverse health effects

Geographic variation in risk factors for SFG rickettsial and leptospiral exposure in Colombia.

Science.gov (United States)

Padmanabha, Harish; Hidalgo, Marylin; Valbuena, Gustavo; Castaneda, Elizabeth; Galeano, Armando; Puerta, Henry; Cantillo, Cesar; Mantilla, Gilma

2009-10-01

In order to characterize the patterns of human exposure to spotted fever group (SFG) rickettsial and leptospiral infection, IgG surveys were conducted on 642 residents of ten different areas of the rural district of Necoclí, Colombia. Areas were selected based on forest cover and human settlement pattern, and individual risk factors were elucidated through multivariate logistic models, controlling for variance clustering within communities. Overall, prevalence of high antibody titers indicating previous exposure to SFG rickettsia and leptospira was 29.2% and 35.6%, respectively, and both were most prevalent in the same peri-urban neighborhood. Forest cover .10% demonstrated the strongest independent association with leptospiral exposure, followed by homes with outdoor storage sheds. Isolated rural housing was the only variable independently associated with SFG rickettsia exposure. Community-level variables significantly modified the effects of individual risk factors. For both pathogens the eldest quartile was less exposed in periurban areas although there was no age effect overall for either. Females living in population settlements were more exposed to SFG rickettsiae but there was no sex association in isolated rural houses. Similarly, in sites with forest cover .10%, individuals working at home had higher leptospira seroprevalence, but place of work was not a risk factor in areas of forest cover ,10%. These data suggest that the patterns of maintenance and/or exposure to leptospira and rickettsia vary across different human created landscapes and settlement patterns. While contrasting risk factors may reflect the unique transmission cycles of each pathogen, the observed patterns of geographic variation suggest that both diseases may respond similarly larger scale human-ecological dynamics.

Developmental effects of exposures to environmental factors: the Polish Mother and Child Cohort Study.

Science.gov (United States)

Polanska, Kinga; Hanke, Wojciech; Sobala, Wojciech; Trzcinka-Ochocka, Malgorzata; Ligocka, Danuta; Brzeznicki, Slawomir; Strugala-Stawik, Halina; Magnus, Per

2013-01-01

This paper estimates the effects of exposure to environmental factors, including lead, mercury, environmental tobacco smoke (ETS), and polycyclic aromatic hydrocarbons (PAH), on child psychomotor development. The study population consists of mother-child pairs in the Polish Mother and Child Cohort Study. Prenatal and postnatal exposure to environmental factors was determined from biomarker measurements as follows: for lead exposure--cord blood lead level, for mercury--maternal hair mercury level, for ETS--cotinine level in saliva and urine, and for PAH--1-hydroxypyrene (1-HP) in urine. At the age of 12 (406 subjects) and 24 months (198 subjects) children were assessed using Bayley Scales of Infant and Toddler Development. There were no statistically significant effects of prenatal exposure to mercury or 1-HP on child psychomotor development. After adjusting for potential confounders, adverse effects of prenatal exposure to ETS on motor development ( β = -2.6; P = 0.02) and postnatal exposure to ETS on cognitive ( β = -0.2; P = 0.05) and motor functions ( β = -0.5; P = 0.01) were found. The adverse effect of prenatal lead exposure on cognitive score was of borderline significance ( β = -6.2; P = 0.06). The study underscores the importance of policies and public health interventions that aim to reduce prenatal and postnatal exposure to lead and ETS.

Adjustment and Prediction of X-Ray Machine Factors Based on Neural Artificial Inculcating

International Nuclear Information System (INIS)

Hussein, A.Z.; Amin, E.S.; Ibrahim, M.S.

2009-01-01

Since the discovery of X-rays, their use in examination has become an integral part of medical diagnostic radiology. The use of X-rays is harmful to human beings but recent technological advances and regulatory constraints have made the medical X-rays much safer than they were at the beginning of the 20th century. However, the potential benefits of the engineered safety features can not be fully realized unless the operators are aware of these safety features. The aim of this work is to adjust and predict X-ray machine factors (current and voltage) using neural artificial network in order to obtain effective dose within the range of dose limitation system and assure radiological safety.

Isotopic Evidence for Multi-stage Cosmic-ray Exposure Histories of Lunar Meteorites: Long Residence on the Moon and Short Transition to the Earth

Energy Technology Data Exchange (ETDEWEB)

Hidaka, Hiroshi; Sakuma, Keisuke [Department of Earth and Planetary Sciences, Nagoya University Nagoya 464-8601 (Japan); Nishiizumi, Kunihiko [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Yoneda, Shigekazu, E-mail: hidaka@eps.nagoya-u.ac.jp [Department of Science and Engineering, National Museum of Nature and Science Tsukuba 305-0005 (Japan)

2017-06-01

It is known that most lunar meteorites have complicated cosmic-ray exposure experiences on the Moon and in space. In this study, cosmic-ray irradiation histories of six lunar meteorites, Dhofar 489, Northwest Africa 032 (NWA 032), NWA 479, NWA 482, NWA 2995, and NWA 5000, were characterized from neutron-captured isotopic shifts of Sm and Gd, and from the abundances of long-lived cosmogenic radionuclides like {sup 10}Be, {sup 26}Al, {sup 36}Cl, and {sup 41}Ca. Sm and Gd isotopic data of all of six meteorites show significant isotopic shifts of {sup 149}Sm–{sup 150}Sm and {sup 157}Gd–{sup 158}Gd caused by accumulation of neutron capture reactions due to cosmic-ray irradiation, corresponding to the neutron fluences of (1.3–9.6) × 10{sup 16} n cm{sup −2}. In particular, very large Sm and Gd isotopic shifts of NWA 482 are over those of a lunar regolith 70002, having the largest isotopic shifts among the Apollo regolith samples, corresponding to cosmic-ray exposure duration over 800 million years in the lunar surface (2 π irradiation). Meanwhile, the concentrations of cosmogenic radionuclides for individual six meteorites show the short irradiation time less than one million years as their bodies in space (4 π irradiation). Our data also support the results of previous studies, revealing that most of lunar meteorites have long exposure ages at shallow depths on the Moon and short transit times from the Moon to the Earth.

Long-term effects of prenatal x-ray of human females: growth and development

International Nuclear Information System (INIS)

Meyer, M.B.; Tonascia, J.

1981-01-01

Experimental studies and studies of survivors of in-utero exposure to atomic bomb blasts have shown significant stunting of growth and mental retardation following these exposures. Central nervous system damage following very low dosage of x-ray at around the time of birth has also been observed in experimental animals. This long term followup study of 1458 human females exposed in-utero to diagnostic x-rays and of 1458 matched unexposed controls studied in Baltimore, Maryland, included measurements of height, weight, and school achievement. Women who had been exposed to x-rays in-utero were significantly shorter in their mid-twenties than were their matched, unexposed controls, even after adjustment for other social and economic factors. However, additional followup revealed that mothers of exposed women were also shorter than the control mothers. Short stature appeared to be a selective factor for x-ray during pregnancy (mostly pelvimetry, 1947 to 1952). Mothers' and daughters' heights were similarly correlated among exposed and controlled mother-daughter pairs, suggesting that the height differences between exposed daughters and their controls were due to these selective factors rather than to any direct effect of radiation on growth. Exposed women reported poorer school achievement than control women. However, except for a higher proportion of exposed women leaving school because of pregnancy, these measurements were no longer significantly different when rates were simultaneously adjusted for socioeconomic differences between exposed and control women

Radiation exposure during equine radiography

International Nuclear Information System (INIS)

Ackerman, N.; Spencer, C.P.; Hager, D.A.; Poulos, P.W. Jr.

1988-01-01

All personnel present in the X-ray examination room during equine radiography were monitored using low energy direct reading ionization chambers (pockets dosimeters) worn outside the lead apron at neck level. The individuals' task and dosimeter readings were recorded after each examination. Average doses ranged from 0 to 6 mrad per study. The greatest exposures were associated with radiography of the shoulder and averaged less than 4 mrad. The individual extending the horse's limb was at greatest risk although the individual holding the horse's halter and the one making the X-ray exposure received similar exposures. A survey of the overhead tube assembly used for some of the X-ray examinations also was performed. Meter readings obtained indicated an asymetric dose distribution around the tube assembly, with the highest dose occurring on the side to which the exposure cord was attached. Although the exposures observed were within acceptable limits for occupational workers, we have altered our protocol and no longer radiograph the equine shoulder unless the horse is anesthetized. Continued use of the pocket dosimeters and maintenance of a case record of radiation exposure appears to make the technologists more aware of radiation hazards

Patient size and x-ray technique factors in head computed tomography examinations. II. Image quality

International Nuclear Information System (INIS)

Huda, Walter; Lieberman, Kristin A.; Chang, Jack; Roskopf, Marsha L.

2004-01-01

We investigated how patient head characteristics, as well as the choice of x-ray technique factors, affect lesion contrast and noise values in computed tomography (CT) images. Head sizes and mean Hounsfield unit (HU) values were obtained from head CT images for five classes of patients ranging from the newborn to adults. X-ray spectra with tube voltages ranging from 80 to 140 kV were used to compute the average photon energy, and energy fluence, transmitted through the heads of patients of varying size. Image contrast, and the corresponding contrast to noise ratios (CNRs), were determined for lesions of fat, muscle, and iodine relative to a uniform water background. Maintaining a constant image CNR for each lesion, the patient energy imparted was also computed to identify the x-ray tube voltage that minimized the radiation dose. For adults, increasing the tube voltage from 80 to 140 kV changed the iodine HU from 2.62x10 5 to 1.27x10 5 , the fat HU from -138 to -108, and the muscle HU from 37.1 to 33.0. Increasing the x-ray tube voltage from 80 to 140 kV increased the percentage energy fluence transmission by up to a factor of 2. For a fixed x-ray tube voltage, the percentage transmitted energy fluence in adults was more than a factor of 4 lower than for newborns. For adults, increasing the x-ray tube voltage from 80 to 140 kV improved the CNR for muscle lesions by 130%, for fat lesions by a factor of 2, and for iodine lesions by 25%. As the size of the patient increased from newborn to adults, lesion CNR was reduced by about a factor of 2. The mAs value can be reduced by 80% when scanning newborns while maintaining the same lesion CNR as for adults. Maintaining the CNR of an iodine lesion at a constant level, use of 140 kV increases the energy imparted to an adult patient by nearly a factor of 3.5 in comparison to 80 kV. For fat and muscle lesions, raising the x-ray tube voltage from 80 to 140 kV at a constant CNR increased the patient dose by 37% and 7

Pregnant x-ray technologist: providing adequate radiation safety for the fetus

International Nuclear Information System (INIS)

Caprio, M.L. Jr.

1980-01-01

The human embryo-fetus is highly radiosensitive and must be protected from excessive exposure to ionizing radiation. The maximum permissible dose equivalent for the developing embryo-fetus is set at 0.5 rem per year - the MPD level for members of the general public. Methods by which supervisory personnel can limit the fetal dose incurred by the occupational exposure of the mother are presented. It is recommended that supervisory personnel attempt to limit occupational exposure to the current non-occupational MPD levels for all x-ray technologists, thereby, insuring that the fetal dose limits are not surpassed and providing an added safety factor for personnel by keeping exposures as low as reasonably achievable

A new approximating formula for calculating gamma-ray buildup factors in multilayer shields

International Nuclear Information System (INIS)

Assad, A.; Chiron, M.; Nimal, J.C.; Diop, C.M.; Ridoux, P.

1999-01-01

This study proposes a new approximating formula for calculating gamma-ray buildup factors in multilayer shields. The formula combines the buildup factors of single-layer shields with products and quotients. The feasibility of the formula for reproducing the buildup factors was tested by using point isotropic buildup factors calculated with the SN1D discrete ordinates code as reference data. The dose buildup factors of single-, double-, and multilayer shields composed of water, aluminum, iron, and lead were calculated for a spherical geometry in the energy range between 10 MeV and 40 keV and for total thicknesses of up to 30 mean free paths. The calculation of the buildup factors takes into account the bound electron effect of Compton scattering (incoherent scattering), the coherent scattering, the pair production, and the secondary sources of bremsstrahlung and fluorescence. The tests have shown that the approximating formula reproduces the reference data of double-layer shields very well for most cases. With the same parameters and with a new physical consideration that takes into account in a global way the degradation of the gamma-ray energy spectrum, the buildup factors of three- and five-layer shields were also very well reproduced

Radiation exposure of medical staff from interventional x-ray procedures: a multicentre study

International Nuclear Information System (INIS)

Haeusler, Uwe; Brix, Gunnar; Czarwinski, Renate

2009-01-01

The purpose of this study was to analyse the radiation exposure of medical staff from interventional x-ray procedures. Partial-body dose measurements were performed with thermoluminescent dosimeters (TLD) in 39 physicians and nine assistants conducting 73 interventional procedures of nine different types in 14 hospitals in Germany. Fluoroscopy time and the dose-area product (DAP) were recorded too. The median (maximum) equivalent body dose per procedure was 16 (2,500) μSv for an unshielded person; the partial-body dose per procedure was 2.8 (240) μSv to the eye lens, 4.1 (730) μSv to the thyroid, 44 (1,800) μSv to one of the feet and 75 (13,000) μSv to one of the hands. A weak correlation between fluoroscopy time or DAP and the mean TLD dose was observed. Generally, the doses were within an acceptable range from a radiation hygiene point of view. However, relatively high exposures were measured to the hand in some cases and could cause a partial-body dose above the annual dose limit of 500 mSv. Thus, the use of finger dosimeters is strongly recommended. (orig.)

Influence of various factors on individual radiation exposure from the chernobyl disaster

Directory of Open Access Journals (Sweden)

Bondar Alexandra

2002-10-01

Full Text Available Abstract Background The explosion at the Chernobyl Nuclear Power Plant was one of the greatest known nuclear disasters of the 20th century. To reduce individual exposure to ionizing radiation the Soviet Union government introduced a number of counter-measures. This article presents a description of how historical events conspired to disrupt these efforts and affect residents in exposed areas. Methods This study employed an extensive review of data on radionuclide deposition, contamination patterns and lifestyle characteristics. Data were obtained from the Ukraine Ministry of Health and the Ukraine Research Center for Radiation Medicine. Results Data are presented on annual contamination rates in selected locales as well as data on local food consumption patterns. Historical factors including economic and political circumstances are also highlighted. Results show the diminution of individual doses between 1987 and 1991 and then an increase between 1991 and 1994 and the relationship between this increase and changes in the lifestyle of the local population. Conclusion A number of factors played direct and indirect roles in contributing to the populace's cumulative radiation exposure. Future post-contamination studies need to consider these factors when estimating individual exposures.

Influence of various factors on individual radiation exposure from the Chernobyl disaster.

Science.gov (United States)

Zamostian, Pavlo; Moysich, Kirsten B; Mahoney, Martin C; McCarthy, Philip; Bondar, Alexandra; Noschenko, Andrey G; Michalek, Arthur M

2002-10-29

The explosion at the Chernobyl Nuclear Power Plant was one of the greatest known nuclear disasters of the 20th century. To reduce individual exposure to ionizing radiation the Soviet Union government introduced a number of counter-measures. This article presents a description of how historical events conspired to disrupt these efforts and affect residents in exposed areas. This study employed an extensive review of data on radionuclide deposition, contamination patterns and lifestyle characteristics. Data were obtained from the Ukraine Ministry of Health and the Ukraine Research Center for Radiation Medicine. Data are presented on annual contamination rates in selected locales as well as data on local food consumption patterns. Historical factors including economic and political circumstances are also highlighted. Results show the diminution of individual doses between 1987 and 1991 and then an increase between 1991 and 1994 and the relationship between this increase and changes in the lifestyle of the local population. A number of factors played direct and indirect roles in contributing to the populace's cumulative radiation exposure. Future post-contamination studies need to consider these factors when estimating individual exposures.

Studies on the radiation exposure and protection at the X-ray radiography in the medical care at home

International Nuclear Information System (INIS)

Suzuki, Shoichi; Fujii, Shigehisa; Asada, Yasuo; Orito, Takeo; Kamei, Tetsuya; Koga, Sukehiko

1998-01-01

Since there are scarce studies on the exposure and protection at the radiography in the medical care at home, authors performed such studies as comparison of doses from self-rectifying and inverter tubes, exposure and protection to patients and nursing persons and actual measurement (October, 1997) at home in Tohno city, Iwate prefecture, of scattering radiation dose at radiography. Apparatuses used were: Portable X-ray equipments; self-rectifying types (Toshiba TR-20 and Medisonacoma PX 30N) and an inverter type (Medisonacoma PX-15HF), Kyoto Kagaku WAC water phantom, X-ray analyzer Model 200 of Kasei Optonics, and Dosimeters (Victoreen Radocon ionization dosimeter and Aloka ICS-301 ionization chamber survey meters). Radiation qualities, surface doses and scattering doses of the equipments under various conditions were compared by the half value layer and effective energy measured with the analyzer. Actual measurement of scattering dose was done at home for 4 patients at chest radiography. Annual dose in monthly ordinary radiography at home, when the distance was >200 cm far from the flux center, was found about 1/100 of 1 mSv (the annual public dose limit), thus securing the safety of nurses. (K.H.)

Studies on the radiation exposure and protection at the X-ray radiography in the medical care at home

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Shoichi; Fujii, Shigehisa; Asada, Yasuo; Orito, Takeo [Fujita Health Univ., Toyoake, Aichi (Japan). School of Health Science; Kamei, Tetsuya; Koga, Sukehiko

1998-12-01

Since there are scarce studies on the exposure and protection at the radiography in the medical care at home, authors performed such studies as comparison of doses from self-rectifying and inverter tubes, exposure and protection to patients and nursing persons and actual measurement (October, 1997) at home in Tohno city, Iwate prefecture, of scattering radiation dose at radiography. Apparatuses used were: Portable X-ray equipments; self-rectifying types (Toshiba TR-20 and Medisonacoma PX 30N) and an inverter type (Medisonacoma PX-15HF), Kyoto Kagaku WAC water phantom, X-ray analyzer Model 200 of Kasei Optonics, and Dosimeters (Victoreen Radocon ionization dosimeter and Aloka ICS-301 ionization chamber survey meters). Radiation qualities, surface doses and scattering doses of the equipments under various conditions were compared by the half value layer and effective energy measured with the analyzer. Actual measurement of scattering dose was done at home for 4 patients at chest radiography. Annual dose in monthly ordinary radiography at home, when the distance was >200 cm far from the flux center, was found about 1/100 of 1 mSv (the annual public dose limit), thus securing the safety of nurses. (K.H.)

Exposure to biomass smoke as a risk factor for oesophageal and ...

African Journals Online (AJOL)

Exposure to biomass smoke as a risk factor for oesophageal and gastric cancer in low-income populations: A systematic review. Violet Kayamba, Douglas C. Heimburger, Douglas R. Morgan, Masharip Atadzhanov, Paul Kelly ...

X-ray phase contrast imaging at MAMI

International Nuclear Information System (INIS)

El-Ghazaly, M.; Backe, H.; Lauth, W.; Kube, G.; Kunz, P.; Sharafutdinov, A.; Weber, T.

2006-01-01

Experiments have been performed to explore the potential of the low emittance 855 MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450 μm, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40 keV. The electron beam spot size had standard deviation σ h =(8.6±0.1) μm in the horizontal and σ v =(7.5±0.1) μm in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4 m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size σ v =(0.50±0.05) μm in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13 x 13 μm 2 provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be σ f =(1.2±0.4) μm, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size in vertical direction of σ v =(1.2±0.3)μm and a

X-ray phase contrast imaging at MAMI

Energy Technology Data Exchange (ETDEWEB)

El-Ghazaly, M.; Backe, H.; Lauth, W.; Kube, G.; Kunz, P.; Sharafutdinov, A.; Weber, T. [Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany)

2006-05-15

Experiments have been performed to explore the potential of the low emittance 855 MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450 {mu}m, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40 keV. The electron beam spot size had standard deviation {sigma}{sub h}=(8.6{+-}0.1) {mu}m in the horizontal and {sigma}{sub v}=(7.5{+-}0.1) {mu}m in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4 m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size {sigma}{sub v}=(0.50{+-}0.05) {mu}m in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13 x 13 {mu}m{sup 2} provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be {sigma}{sub f}=(1.2{+-}0.4) {mu}m, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size

X-ray phase contrast imaging at MAMI

Science.gov (United States)

El-Ghazaly, M.; Backe, H.; Lauth, W.; Kube, G.; Kunz, P.; Sharafutdinov, A.; Weber, T.

2006-05-01

Experiments have been performed to explore the potential of the low emittance 855MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450μm, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40keV. The electron beam spot size had standard deviation σh = (8.6±0.1)μm in the horizontal and σv = (7.5±0.1)μm in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size σv = (0.50±0.05)μm in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13×13μm^2 provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be σf = (1.2±0.4)μm, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size in vertical direction of σv = (1.2±0.3)μm and a geometrical

Environmental Factors Influencing White-Tailed Deer (Odocoileus virginianus Exposure to Livestock Pathogens in Wisconsin.

Directory of Open Access Journals (Sweden)

Shelli Dubay

Full Text Available White-tailed deer (Odocoileus virginianus are commonly exposed to disease agents that affect livestock but environmental factors that predispose deer to exposure are unknown for many pathogens. We trapped deer during winter months on two study areas (Northern Forest and Eastern Farmland in Wisconsin from 2010 to 2013. Deer were tested for exposure to six serovars of Leptospira interrogans (grippotyphosa, icterohaemorrhagiae, canicola, bratislava, pomona, and hardjo, bovine viral diarrhea virus (BVDV-1 and BVDV-2, infectious bovine rhinotracheitis virus (IBR, and parainfluenza 3 virus (PI3. We used logistic regression to model potential intrinsic (e.g., age, sex and extrinsic (e.g., land type, study site, year, exposure to multiple pathogens variables we considered biologically meaningful to exposure of deer to livestock pathogens. Deer sampled in 2010-2011 did not demonstrate exposure to BVDV, so we did not test for BVDV in subsequent years. Deer had evidence of exposure to PI3 (24.7%, IBR (7.9%, Leptospira interrogans serovar pomona (11.7%, L. i. bratislava (1.0%, L. i. grippotyphosa (2.5% and L. i. hardjo (0.3%. Deer did not demonstrate exposure to L. interrogans serovars canicola and icterohaemorrhagiae. For PI3, we found that capture site and year influenced exposure. Fawns (n = 119 were not exposed to L. i. pomona, but land type was an important predictor of exposure to L. i. pomona for older deer. Our results serve as baseline exposure levels of Wisconsin white-tailed deer to livestock pathogens, and helped to identify important factors that explain deer exposure to livestock pathogens.

Time-resolved X-ray PIV technique for diagnosing opaque biofluid flow with insufficient X-ray fluxes.

Science.gov (United States)

Jung, Sung Yong; Park, Han Wook; Kim, Bo Heum; Lee, Sang Joon

2013-05-01

X-ray imaging is used to visualize the biofluid flow phenomena in a nondestructive manner. A technique currently used for quantitative visualization is X-ray particle image velocimetry (PIV). Although this technique provides a high spatial resolution (less than 10 µm), significant hemodynamic parameters are difficult to obtain under actual physiological conditions because of the limited temporal resolution of the technique, which in turn is due to the relatively long exposure time (~10 ms) involved in X-ray imaging. This study combines an image intensifier with a high-speed camera to reduce exposure time, thereby improving temporal resolution. The image intensifier amplifies light flux by emitting secondary electrons in the micro-channel plate. The increased incident light flux greatly reduces the exposure time (below 200 µs). The proposed X-ray PIV system was applied to high-speed blood flows in a tube, and the velocity field information was successfully obtained. The time-resolved X-ray PIV system can be employed to investigate blood flows at beamlines with insufficient X-ray fluxes under specific physiological conditions. This method facilitates understanding of the basic hemodynamic characteristics and pathological mechanism of cardiovascular diseases.

Aggregate Exposure and Cumulative Risk Assessment--Integrating Occupational and Non-occupational Risk Factors.

Science.gov (United States)

Lentz, T J; Dotson, G S; Williams, P R D; Maier, A; Gadagbui, B; Pandalai, S P; Lamba, A; Hearl, F; Mumtaz, M

2015-01-01

Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational.

Correction factors for the NMi free-air ionization chamber for medium-energy x-rays calculated with the Monte Carlo method

International Nuclear Information System (INIS)

Grimbergen, T.W.M.; Dijk, E. van; Vries, W. de

1998-01-01

A new method is described for the determination of x-ray quality dependent correction factors for free-air ionization chambers. The method is based on weighting correction factors for mono-energetic photons, which are calculated using the Monte Carlo method, with measured air kerma spectra. With this method, correction factors for electron loss, scatter inside the chamber and transmission through the diaphragm and front wall have been calculated for the NMi free-air chamber for medium-energy x-rays for a wide range of x-ray qualities in use at NMi. The newly obtained correction factors were compared with the values in use at present, which are based on interpolation of experimental data for a specific set of x-ray qualities. For x-ray qualities which are similar to this specific set, the agreement between the correction factors determined with the new method and those based on the experimental data is better than 0.1%, except for heavily filtered x-rays generated at 250 kV. For x-ray qualities dissimilar to the specific set, differences up to 0.4% exist, which can be explained by uncertainties in the interpolation procedure of the experimental data. Since the new method does not depend on experimental data for a specific set of x-ray qualities, the new method allows for a more flexible use of the free-air chamber as a primary standard for air kerma for any x-ray quality in the medium-energy x-ray range. (author)

Measurement of the exposure rate due to low energy x-rays emitted from video display terminals

International Nuclear Information System (INIS)

Campos, L.L.

1988-01-01

Thermoluminescent dosimeters of CaSO 4 :Dy have been used to measure the low energy x-rays emitted from Video Display Terminals (VDTs). For each terminal, three points were measured with five dosimeters at each point. The points were at distances of 5 and 50 cm in front of the screen and at 65 cm with an angle of approximately 50 0 . The last two positions approximate to positions of the lenses of the eye and the gonads respectively. A survey of 50 VDTs at a distance of 5 cm from the screen resulted in exposure rates nearly fifteen times below the exposure rate of 0.5 mR h -1 (0.129 μC kg -1 h -1 ) which is the limit recommended by the International Atomic Energy Agency (IAEA), Safety Series No. 9 (1967) Basic Safety Standards for Radiation Protection. (author)

Influence of occupational exposure to pesticides on the level of DNA damage induced in human lymphocytes (Polish group) by UV-C and X-rays

International Nuclear Information System (INIS)

Dyga, W.; Drag, Z.; Cebulska-Wasilewska, A.

2002-01-01

The aim of this study was to find out whether occupational exposure to pesticides might affect the individual susceptibility of various donors to the induction of DNA damage by genotoxic agents (UV-C, X-rays) and the efficiency of cellular repair. Previously cryo preserved lymphocytes were defrosted, and DNA damage in the lymphocytes prior to any in vitro studies was investigated with the application of the Comet assay. In order to evaluate the susceptibilities of human lymphocytes to genotoxic agents and the variability of repair capacities, the DNA migrations were estimated immediately after exposure to UV-C light or X-rays and after two hours. On average, the DNA damage detected in untreated lymphocytes was significantly higher in the group exposed to pesticides than in reference group. UV-C treated lymphocytes from group exposed to pesticides shows a greater statistically significant level of DNA migration compared to the reference group, detected after 2 hours incubation in the absence of PHA. Significantly lower responses to X-rays and higher levels of residual DNA damage were detected in the lymphocytes of donors from the group exposed to pesticides compared with the reference group. In conclusion, our results suggest that occupational exposure to pesticides influences the level of induced DNA damage, and the cellular capabilities of repair. (author)

Effect of in utero exposure to diagnostic doses of X-rays on the growth and behaviour of mouse

International Nuclear Information System (INIS)

Prakash Hande, M.; Uma Devi, P.

1992-01-01

Intrauterine development, particularly the period of organogenesis is an especially radiosensitive phase in mammals. Teratogenic effect of low dose irradiation has been demonstrated in laboratory animals. Several studies have indicated the vulnerability of the developing human brain to radiation injury and demonstrated changes in postnatal behaviour following intrauterine animal irradiation. However, data are lacking on the comparative response of the different stages of prenatal development to low doses at levels that could result from diagnostic radiation exposure. This study attempts to empirically evaluate the differential response of critical stages in prenatal development of mouse to single low dose exposures to diagnostic X-rays. Data on growth and behaviour are briefly presented. (author). 22 refs., 2 figs., 1 tab

Radiation risk to the patient: a case study involving multiple diagnostic X ray exposures given over a period of 25 years

International Nuclear Information System (INIS)

Rainbow, A.J.; McMaster Univ., Hamilton, ON; Roginski, P.; McGeen, W.

1992-01-01

The cumulative somatic dose index (SDI) for a number of diagnostic X ray examinations was made for a 60 year old male. The history of diagnostic X ray exposure for this patient from 1957 to 1983 showed 29 diagnostic X ray examinations including more than 100 films and 15 minutes of fluoroscopy. The total cumulative SDI to this patient was 214 mGy (about 21 rad). More than half this dose, 142 mGy, was contributed from upper GI and barium enema examinations which used fluoroscopy, with 88 mGy from the fluoroscopy alone. Using the recently revised risk coefficient for fatal cancer following whole-body irradiation of adult workers recommended by the International Commission on Radiological Protection in 1990, the authors estimate a 0.9% cancer morality risk to this patient resulting from the 29 diagnostic X ray examinations. (author)

Exposure Scenarios and Unit Dose Factors for the Hanford Immobilized Low Activity Tank Waste Performance Assessment

Energy Technology Data Exchange (ETDEWEB)

RITTMANN, P.D.

1999-12-29

Exposure scenarios are defined to identify potential pathways and combinations of pathways that could lead to radiation exposure from immobilized tank waste. Appropriate data and models are selected to permit calculation of dose factors for each exposure

An ignored risk factor in toxicology: The total imprecision of exposure assessment

DEFF Research Database (Denmark)

Grandjean, Philippe; Budtz-Jørgensen, Esben

2010-01-01

twice as much for maternal hair. The total imprecision of these biomarkers much exceeded the normal laboratory variability of less than 5%. Such imprecision can cause underestimation of dose-related toxicity, and data analysis should therefore include sensitivity analyses that take this factor...... were determined in cord blood, cord tissue, and maternal hair. We determined their mutual correlations and their associations with the child's neurobehavioral effect variables at age 7 years. The exposure biomarkers correlated well with one another, but the cord blood mercury concentration showed......Quality assurance of exposure biomarkers usually focuses on laboratory performance only. Using data from a prospective birth cohort study in the Faroe Islands, we have assessed the total imprecision of exposure biomarkers. As biomarkers of prenatal methylmercury exposure, mercury concentrations...

Saffron extracts effect on processes in brain structures under exposure to x-ray irradiation of medium dose

International Nuclear Information System (INIS)

Rzaeva, A.

2012-01-01

Full text : Process of ionizing radiation on live organism is accompanied by interaction of free radicals (FR) with molecules of proteins, nucleic acids and lipids. In its turn, FR occurs subsequently by excitation and ionization of molecules. Besides all, ionizing radiation becomes the reason of accumulation in body tissues of toxic products (radio toxic) that strengthen beam effect. Endogenous antioxidatic system (EAS) of an organism plays a significant role in detoxication of redundant quantity of FR formed in cells. Ionizing radiation influences negatively to high-grade functioning of basic EAS enzymes. Besides, during radiation injuries, the level of FR increases. In case of its exhaustion and lack insertion of natural antioxidants (bioantioxidants) to organism plays a therapeutic role. Thus, in our work we used saffron extract in experiments with the purpose of studying its effect on the activity of antioxidant enzymes at radiation influence. Determination of proteins has been carried out with Lowry method. In the result of carried-out researches, it has been detected fixed dynamics of activity change of antioxidant enzymes in various brain structures of white rats within x-ray irradiation at medium dose, and joint impact of x-ray radiation of saffron extract. Under exposure to X-ray irradiation of medium dose in some brain structures decreasing of catalase activity was revealed. Tendency towards decreasing is more developed on the 3th day of irradiation. As opposed to catalase activity GPO activity was increased. Insertion of saffron extract to experimental animals (for 21 days before irradiation) conducive to prevention the decreasing of catalase activity stabilizes GPO activity and exerts an effective influence. Thereby, bioantioxidants have significant role in the regulation of processes occurred in tissues and cells under the influence of extreme factors. Antioxidant protection system of organism carries out continuous protection of organism from toxic

Long-term effects of prenatal x-ray of human females. II. Growth and development.

Science.gov (United States)

Meyer, M B; Tonascia, J

1981-09-01

Experimental studies and studies of survivors of in-utero exposure to atomic bomb blasts have shown significant stunting of growth and mental retardation following these exposures. Central nervous system damage following very low doses of x-ray at around the time of birth has also been observed in experimental animals. This long term follow-up studies of 1458 human females exposed in utero to diagnostic x-rays and of 1458 matched unexposed controls studied in Baltimore, Maryland, included measurements of height, weight and school achievement. Women who had been exposed to x-rays in utero were significantly shorter in their mid-twenties than were their matched, unexposed controls, even after adjustment for other social and economic factors. However, additional follow-up revealed that mothers of exposed women were also shorter than the control mothers. Short stature appeared to be a selective factor for x-ray during pregnancy (mostly pelvimetry, 1947-1952). Mothers' and daughters' heights were similarly correctly among exposed and control mother-daughter pairs, suggesting that the height differences between exposed daughters and their controls were due to these selective factor rather than to any direct effect of radiation on growth. Exposed women reported poorer school achievement than control women. However, except for a higher proportion of exposed women leaving school because of pregnancy, these measurements were no longer significantly different when rates were simultaneously adjusted for socioeconomic differences between exposed and control women.

Development of a head simulator for exposure dose estimation on patients exposed by odontological X-rays

International Nuclear Information System (INIS)

Moura Neto, Francisco N.; Batista, Eutropio V.; Santos, Adriano M.

2009-01-01

In the obtaining a odontological radiography, the individual is exposed to te radiation and part of that radiation will be absorbed by his organism. The estimative of absorbed dose can be accomplished through calculations where are considered: the distance from the source to the individual, the energy of the emitted X-ray at the moment of the exposure and the bode region exposed; and as that option does not possess great precision, alternative forms are seek for the quantification such doses. This work proposes the construction of a head simulator to be used in the estimative of absorbed dose in patients, during the accomplishment of the odontological radiographic examinations. As a perspective of work, it is intended to use the phantom to help in the absorbed doses for obtainment of parameters in X-ray odontological devices, contributing of image obtainment with more quality and less radiation dose in the patient

Radio-epidemiological study on medical X-ray workers in China

International Nuclear Information System (INIS)

Wang, Jixian; Zhao, Yongcheng; Li, Benxiao; Zhang, Liangan; Wang, Zhiquan; Zhang, Jingyuan; Jia, Weihua

2008-01-01

Cancer incidence and non-cancer disease mortality (1950-1995) among 27,011 medical X-ray workers was compared with that of 25,782 other medical specialists employed between 1950 and 1980. Significantly elevated cancer risks were found for leukemia and cancers of skin, female breast, lung, liver, bladder and esophagus, the RRs were 2.2, 4.1, 1.3, 1.2, 1.2, 1.8 and 2.7 respectively. The patterns of risk associated with years since beginning X-ray work and with age and calendar year of initial employment suggest that the excesses of leukemia, skin cancer and female breast cancer were related to occupational exposure to X-rays. Significantly elevated non-cancer disease risks were blood forming system diseases ( mainly from aplastic anemia ), nervous system diseases, coronary heart disease and stroke, and the RRs were 3.7, 2.1, 1.4 and 1.4 respectively. The analysis of risk patterns suggest that the excess RRs for blood forming system diseases and coronary heart disease and stroke in the earlier cohort might be related to radiation exposure, but for the later cohort the excess RRs of nervous system diseases and coronary heart disease and stroke could be more attributed to factors of other than radiation. The possible confounding effects of risk factors other than radiation were discussed. (author)

Effective energies and exposure determinations of two different energy X-ray beams incident on a personnel monitor

International Nuclear Information System (INIS)

Okuno, E.; Cruz, M.T. da

1984-01-01

The effective energy of one X or gamma ray beam can be determined by means of two thermoluminescent (TL) dosemeters mounted between suitable filters. However, it has been observed that personnel monitors exposed to two different energy ionizing radiations provide different effective energies depeding on the type of TL phosphor used. This fact could be a powerful tool for identifying exposures to radiation with quite different effective energies which are very common in practice. Two types of TL dosemeters were used : pellets of cold pressed natural fluoride and NaCl developed in our own laboratory, and LiF, TLD-100 from Harshaw Chemical Co.. Experimental results obtained with these combined dosemeters after irradiation with different sets of exposures and energy values of ionizing radiations are also presented. (Author) [pt

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate ...

Indoor Residential Chemical Exposures as Risk Factors for Asthmaand Allergy in Infants and Children: a Review

Energy Technology Data Exchange (ETDEWEB)

Mendell, M.J.

2006-03-01

Most research into effects of residential indoor air exposures on asthma and allergies has focused on exposures to biologic allergens, moisture and mold, endotoxin, or combustion byproducts. This paper briefly reviews reported findings on associations of asthma or allergy in infants or children with risk factors related to indoor chemical emissions from residential materials or surface coatings. Associations, some strong (e.g., odds ratios up to 13), were reported. The most frequently identified risk factors were formaldehyde, aromatic organic compounds such as toluene and benzene, plastic materials and plasticizers, and recent painting. Exposures and consequent effects from indoor sources may be exacerbated by decreased ventilation. Identified risk factors may be proxies for correlated exposures. Findings suggest the frequent occurrence of important but preventable effects on asthma and allergy in infants and children worldwide from modern residential building materials and coatings.

Vision 20/20: Increased image resolution versus reduced radiation exposure

International Nuclear Information System (INIS)

Ritman, Erik L.

2008-01-01

This is a review of methods, currently and potentially, available for significantly reducing x-ray exposure in medical x-ray imaging. It is stimulated by the radiation exposure implications of the growing use of helical scanning, multislice, x-ray computed tomography for screening, such as for coronary artery atherosclerosis and cancer of the colon and lungs. Screening requires high-throughput imaging with high spatial and contrast resolution to meet the need for high sensitivity and specificity of detection and classification of specific imaged features. To achieve this goal beyond what is currently available with x-ray imaging methods requires increased x-ray exposure, which increases the risk of tissue damage and ultimately cancer development. These consequences limit the utility of current x-ray imaging in screening of at-risk subjects who have not yet developed the clinical symptoms of disease. Current methods for reducing x-ray exposure in x-ray imaging, mostly achieved by increasing sensitivity and specificity of the x-ray detection process, may still have potential for an up-to-tenfold decrease. This could be sufficient for doubling the spatial resolution of x-ray CT while maintaining the current x-ray exposure levels. However, a spatial resolution four times what is currently available might be needed to adequately meet the needs for screening. Consequently, for the proposed need to increase spatial resolution, an additional order of magnitude of reduction of x-ray exposure would be needed just to keep the radiation exposure at current levels. This is conceivably achievable if refraction, rather than the currently used attenuation, of x rays is used to generate the images. Existing methods that have potential for imaging the consequences of refracted x ray in a clinical setting are (1) by imaging the edge enhancement that occurs at the interfaces between adjacent tissues of different refractive indices, or (2) by imaging the changes in interference

An epidemiological study on patient exposure from dental radiography

International Nuclear Information System (INIS)

Ehara, Masahiro

1980-01-01

The gonadal and bone marrow doses received by patients per exposure from dental X-ray examinations are small when compared to those of other medical X-ray procedures. Therefore, the contribution from dental X-ray exposure dose has not been discussed in terms of individual dose, but has always been considered in terms of population dose. However, depending on the peculiarity of the disease involved, some dental patients are considered to be subjected to relatively large doses of diagnostic X-rays. Therefore, from the standpoint of overall radiation protection, it was felt important to estimate the maximum individual dose incurred by diagnostic dental radiography. An epidemiological survey was undertaken at Osaka Dental University Hospital to estimate the maximum radiation exposure doses to various organs by projection. A total of 1301 patients were randomly selected from among persons who had initially visited the Radiology Department and subsequently received many X-ray exposures. The individual exposure dose to each organ was determined by projection based on the type and number of examinations. Results showed that the conditions incurring the maximum exposure dose in individual patients for diagnostic purposes in the dental region was those with ameloblastoma. (author)

Modeling the X-ray Process, and X-ray Flaw Size Parameter for POD Studies

Science.gov (United States)

Koshti, Ajay M.

2014-01-01

Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances, the NDE flaw detectability is given as a flaw size such as crack length. The flaw is either a crack or behaving like a crack in terms of affecting the structural integrity of the material. An alternate approach is to use a more complex flaw size parameter. The X-ray flaw size parameter, given here, takes into account many setup and geometric factors. The flaw size parameter relates to X-ray image contrast and is intended to have a monotonic correlation with the POD. Some factors such as set-up parameters, including X-ray energy, exposure, detector sensitivity, and material type that are not accounted for in the flaw size parameter may be accounted for in the technique calibration and controlled to meet certain quality requirements. The proposed flaw size parameter and the computer application described here give an alternate approach to conduct the POD studies. Results of the POD study can be applied to reliably detect small flaws through better assessment of effect of interaction between various geometric parameters on the flaw detectability. Moreover, a contrast simulation algorithm for a simple part-source-detector geometry using calibration data is also provided for the POD estimation.

Woodstove exposure as a risk factor for airway obstruction

Directory of Open Access Journals (Sweden)

Alexandros Mpagordakis

2015-06-01

Full Text Available Background: The recent financial crisis in Greece has significantly increased woodstove use and therefore the indoor air pollution of the household atmosphere. Related studies have shown that indoor air pollution is associated with the onset of obstructive airway diseases, especially in women who are occupied with household duties. Aim: To investigate whether the woodstove exposure is a risk factor of obstructive airway disease especially in nonsmoking women. Methods: In this cross-sectional study participated 410 individuals (51.7% women, mean age 56,1 ± 13,0 years, ranging from 40 to 93 years old who visited eight Primary Health Care Settings on the island of Crete, Greece. A spirometry testing was performed to assess the degree of airflow limitation setting criteria the fixed ratio of spirometry values (FEV1 / FVC 17] were establish in non-smoker women who were exposed for 30.2 years to woodstove smoke compared to non-COPD non-smoker women (11.8 years exposure, despite the fact that interactions terms (female gender, smoking, woodstove use, cough with sputum production were not associated with COPD development. Conclusion: The present study confirms that woodstove exposure (about 30 years is associated with Airway Obstruction in non-smoker women. Also, a greater woodstove exposure is indicative of a greater prevalence of airflow limitation and a greater COPD-related symptoms.

ACTINIDE AND ULTRA-HEAVY ABUNDANCES IN THE LOCAL GALACTIC COSMIC RAYS: AN ANALYSIS OF THE RESULTS FROM THE LDEF ULTRA-HEAVY COSMIC-RAY EXPERIMENT

Energy Technology Data Exchange (ETDEWEB)

Donnelly, J. [Dublin Institute of Technology (DIT), School of Physics, Kevin Street, Dublin 8 (Ireland); Thompson, A.; O' Sullivan, D.; Daly, J.; Drury, L. [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Domingo, V.; Wenzel, K.-P. [European Space Research and Technology Centre (ESTEC), Keplerlaan 1, Postbus 299, 2200 AG Noordwijk (Netherlands)

2012-03-01

The LDEF Ultra-Heavy Cosmic-Ray Experiment (UHCRE) detected Galactic cosmic rays (GCRs) of charge Z {>=} 70 in Earth orbit with an exposure factor of 170 m{sup 2} sr yr, much larger than any other experiment. The major results include the first statistically significant uniform sample of GCR actinides with 35 events passing quality cuts, evidence for the existence of transuranic nuclei in the GCR with one {sub 96}Cm candidate event, and a low {sub 82}Pb/{sub 78}Pt ratio consistent with other experiments. The probability of the existence of a transuranic component is estimated as 96%, while the most likely {sub 92}U/{sub 90}Th ratio is found to be 0.4 within a wide 70% confidence interval ranging from 0 to 0.96. Overall, the results are consistent with a volatility-based acceleration bias and source material which is mainly ordinary interstellar medium material with some recent contamination by freshly synthesized material. Uncertainty in the key {sub 92}U/{sub 90}Th ratio is dominated by statistical errors resulting from the small sample size and any improved determination will thus require an experiment with a substantially larger exposure factor than the UHCRE.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. ...

Assessment of relevant factors and relationships concerning human dermal exposure to pesticides in greenhouse applications.

Science.gov (United States)

Martínez Vidal, Jose L; Egea González, Francisco J; Garrido Frenich, Antonia; Martínez Galera, María; Aguilera, Pedro A; López Carrique, Enrique

2002-08-01

Principal component analysis (PCA) was applied to the gas chromatographic data obtained from 23 different greenhouse trials. This was used to establish which factors, including application technique (very small, small, medium and large drop-size), crop characteristics (short/tall, thin/dense) and pattern application of the operator (walking towards or away from the treated area) are relevant to the dermal exposure levels of greenhouse applicators. The results showed that the highest exposure by pesticides during field applications in greenhouses, in the climatic conditions and in the crop conditions typical of a southern European country, occurs on the lower legs and front thighs of the applicators. Similar results were obtained by hierarchical cluster analysis (HCA). Drop-size seems to be very important in determining total exposure, while height and density of crops have little influence on total exposure under the conditions of the present study. No pesticide type is a major factor in total exposure. The application of multiple regression analysis (MRA) allowed assessment of the relationships between the pesticide exposure of the less affected parts of the body with the most affected parts.

Developmental Effects of Exposures to Environmental Factors: The Polish Mother and Child Cohort Study

Directory of Open Access Journals (Sweden)

Kinga Polanska

2013-01-01

Full Text Available This paper estimates the effects of exposure to environmental factors, including lead, mercury, environmental tobacco smoke (ETS, and polycyclic aromatic hydrocarbons (PAH, on child psychomotor development. The study population consists of mother-child pairs in the Polish Mother and Child Cohort Study. Prenatal and postnatal exposure to environmental factors was determined from biomarker measurements as follows: for lead exposure—cord blood lead level, for mercury—maternal hair mercury level, for ETS—cotinine level in saliva and urine, and for PAH—1-hydroxypyrene (1-HP in urine. At the age of 12 (406 subjects and 24 months (198 subjects children were assessed using Bayley Scales of Infant and Toddler Development. There were no statistically significant effects of prenatal exposure to mercury or 1-HP on child psychomotor development. After adjusting for potential confounders, adverse effects of prenatal exposure to ETS on motor development (β = −2.6; P=0.02 and postnatal exposure to ETS on cognitive (β = −0.2; P=0.05 and motor functions (β = −0.5; P=0.01 were found. The adverse effect of prenatal lead exposure on cognitive score was of borderline significance (β = −6.2; P=0.06. The study underscores the importance of policies and public health interventions that aim to reduce prenatal and postnatal exposure to lead and ETS.

Patient and population protection in X-ray examinations -a general roentgenological and health problem

International Nuclear Information System (INIS)

Khadzhidekov, G.; Dermendzhiev, Kh.

1975-01-01

Population exposure in excess of that due to natural radiation background is known to result primarily (to 70-90%) from medical X-rays given in mass screening. Protection of the population is a problem of great concern in present-day radiology and is approached by balancing benefits of diagnostic X-rays against risks presented by the probability of overexposing the patient. An evaluation on such a basis necessitates detailed and accurate information on patient radiation exposure and takes into account factors leading to a population hazard by making assessments in terms of so-called genetically significant doses. Gonad doses have to be carefully analysed, implying a need for studies of various types of X-ray procedures, precautionary measures taken, etc. An important issue in the choice and adoption of an appropriate method for large-scale gonad dose assessments in routine practice. To obtain an estimate of radiation hazard from medical roentgenology in terms of genetically significant doses and identify measures necessary to limit exposure risks, collaborative efforts are needed involving participation of roentgenologists and hygienists, and use of dosimetric, organizational-methodological, and statistical techniques. These efforts should lead to an abrupt reduction in radiation burden to the population from diagnostic X-rays. (author)

Constraints on the bulk Lorentz factor of gamma-ray bursts with the detection rate by Fermi LAT

Science.gov (United States)

Chen, Ye; Liu, Ruo-Yu; Wang, Xiang-Yu

2018-05-01

The bulk Lorentz factor(Γ) of the outflow is an essential parameter to understanding the physics of gamma-ray burst (GRB). Informations about the Lorentz factors of some individual GRBs have been obtained from the spectral features of the high-energy gamma-ray emissions (>100 MeV), assuming that the spectral breaks or cutoffs are due to the pair-production attenuation (i.e., γγ → e+e-). In this paper, we attempt to interpret the dependence of the LAT detection rate of GRBs on the number of high-energy gamma-rays, taking into account the attenuation effect. We first simulate a long-GRB sample with Monte Carlo method using the luminosity function, rate distribution with redshift and properties of the GRB spectrum. To characterize the distribution of the Lorentz factors, we assume that the Lorentz factors follow the relation Γ =Γ _0E_iso,52k, where Eiso, 52 is the isotropic photon energy in unit of 1052erg. After taking into account the attenuation effect related with the above Lorentz factor distribution, we are able to reproduce the LAT-detected rate of GRBs as the function of the number of gamma-rays for suitable choice of the values of Γ0 and k. The result suggests that the distribution of the bulk Lorentz factor for the majority of GRBs is in the range of 50 - 250.

Cancer among medical diagnostic x-ray workers in China

International Nuclear Information System (INIS)

Wang, J.X.; Boice, J.D. Jr.; Li, B.X.; Zhang, J.Y.; Fraumeni, J.F. Jr.

1988-01-01

Cancer incidence among 27,011 diagnostic x-ray workers was compared to that of 25,782 other medical specialists employed between 1950 and 1980 in China. X-ray workers had a 50% higher risk of developing cancer than the other specialists [relative risk (RR) = 1.5; 95% CI = 1.3-1.7]. Leukemia was strongly linked to radiation work (RR = 3.5, n = 30). Cancers of the breast (RR = 1.4, n = 11), thyroid (RR = 2.1, n = 7), and skin (RR = 1.5, n = 6) were increased among x-ray workers employed for 10 or more years. High risks of cancers of the esophagus (RR = 3.5, n = 15) and liver (RR = 2.4, n = 48) were not consistent with a radiation effect since risk did not vary by duration of employment. This finding suggested that some differences might exist between groups of hospital workers in social class, alcohol intake, dietary habits, and other risk factors. No excess lung cancer (RR = 0.9, n = 22) or multiple myeloma (n = 0) was observed. Significant excesses of leukemia and cancers of the breast and thyroid occurred among x-ray workers first employed prior to 1960 when radiation exposures in China were high. In fact, it was not uncommon for employees to be given time off from x-ray work because their wbc count was severely depressed. These data indicated that repeated exposure to x-rays over many years can increase the risk of leukemia and several other tumors but apparently not that of lung cancer

Measurements of natural radiation exposure rates in various living environment, (2)

International Nuclear Information System (INIS)

Matsuda, Hideharu

1991-01-01

Natural gamma-ray and cosmic-ray exposure rates were measured indoors and outdoors for 94 model houses of housing exhibition centers in Nagoya to obtain basic data for estimation of the population dose. Influence of the structure of houses on indoor exposure rates and relationship between indoor and outdoor natural gamma-ray exposure rates were studied. Exposure rates were measured with a 1.5''φ x 4''NaI(Tl) scintillation counter and a 6''φ spherical plastic scintillation counter. The mean indoor natural gamma-ray exposure rate in ferro-concrete buildings was about 40 % higher than that in fire-proof wooden houses and about 60 % higher than that in light weight steel framed buildings; that in fire-proof wooden houses was about 10 % higher than that in light weight steel framed buildings. The ratio of indoor to outdoor natural gamma-ray exposure rate was found to be 0.95 ± 0.15, 0.77 ± 0.10 and 0.72 ± 0.13 for ferro-concrete buildings, fire-proof wooden houses and light weight steel framed buildings, respectively. The mean indoor cosmic-ray exposure rate in ferro-concrete buildings was 2.8 μR/h, which was about 18 % lower than the outdoor value. The indoor cosmic-ray exposure rate both in fire-proof wooden houses and in light weight steel framed buildings were about 3.2 μR/h, which was 6 % lower than the outdoor value. (author)

Within and between Individual Variability of Exposure to Work-Related Musculoskeletal Disorder Risk Factors

Directory of Open Access Journals (Sweden)

Mohsen Zare

2018-05-01

Full Text Available Industrial companies indicate a tendency to eliminate variations in operator strategies, particularly following implementation of the lean principle. Companies believe when the operators perform the same prescribed tasks, they have to execute them in the same manner (completing the same gestures and being exposed to the same risk factors. They attempt to achieve better product quality by standardizing and reducing operational leeway. However, operators adjust and modify ways of performing tasks to balance between their abilities and the requirements of the job. This study aims to investigate the variability of exposure to physical risk factors within and between operators when executing the same prescribed tasks. The Ergonomic Standard method was used to evaluate two workstations. Seven operators were observed thirty times between repeated cycle times at those workstations. The results revealed the variability of exposure to risk factors between and within operators in the repeated execution of the same tasks. Individual characteristics and operators’ strategies might generate the variability of exposure to risk factors that may be an opportunity to reduce the risks of work-related musculoskeletal disorders (WR-MSDs. However, sometimes operators’ strategies may cause overexposure to risk factors; operators most often adopt such strategies to undertake their tasks while reducing the workload.

Exploring violence exposure, stress, protective factors and behavioral problems among inner-city youth.

Science.gov (United States)

Youngstrom, Eric; Weist, Mark D; Albus, Kathleen E

2003-09-01

This study examined relationships between violence exposure, other stressors, family support, and self-concept on self-reported behavioral problems among 320 urban adolescents (aged 11-18) referred for mental health treatment. Overall, participants reported high levels of violence exposure, with a median of six past encounters with violence as a witness, victim, or through the experiences of associates. All forms of violence exposure (witnessing, being a victim, knowing of victims) were correlated with internalizing and externalizing behavioral problems for males and females. Total violence exposure predicted behavioral problems among participants, even after controlling for the effects of other risk, demographic and protective factors. Family support and self-concept moderated the influence of life stress and cumulative risk on problem behavior outcomes, but these protective variables did not significantly moderate violence exposure.

Improved model for solar cosmic ray exposure in manned Earth orbital flights

International Nuclear Information System (INIS)

Wilson, J.W.; Nealy, J.E.; Atwell, W.; Cucinotta, F.A.; Shinn, J.L.; Townsend, L.W.

1990-06-01

A calculational model is derived for use in estimating Solar cosmic ray exposure to critical body organs in low-Earth orbit at the center of a large spherical shield of fixed thickness. The effects of the Earth's geomagnetic field and the astronauts' self-shielding are evaluated explicitly. The geomagnetic field model is an approximate tilted eccentric dipole with geomagnetic storms represented as a uniform-impressed field. The storm field is related to the planetary geomagnetic index K(sub p). The code is applied to the Shuttle geometry using the Shuttle mass distribution surrounding two locations on the flight deck. The Shuttle is treated as pure aluminum and the astronaut as soft tissue. Short-term, average fluence over a single orbit is calculated as a function of the location of the lines of nodes or long-term averages over all lines of nodes for a fixed inclination

Medical management of severe local radiation injury after acute X-ray exposure

International Nuclear Information System (INIS)

Bushmanov, A.; Nadezhina, N.; Kretov, A.

2008-01-01

Medical management during acute period in a case of severe local radiation injury after acute X-ray exposure includes 3 stages. During the fist stage patient got conservative treatment according to the common pathogenetic mechanisms of LRI (dis aggregating therapy, stimulation of regeneration, dis intoxication therapy, antibiotic therapy, pain relief therapy, Local anti-burn therapy-specific non-adhesive bandage with antiseptic and anti-burn medicaments); estimation of severity, deepness and area of injury by clinical picture and dates of instrumental methods of examining; defining necessity and volume of surgical treatment; preparing arrangements for surgical treatment. This stage ends with forming of demarcation line of a very hard severity of a Local Radiation Injure. The second stage includes necrectomy of the area of a very hard severity with microsurgical plastic by re vascularized flap and auto dermoplastic. The third stage - adaptation of re vascularized flap and total epithelization of injured area. (author)

Dose-modifying factors for skin ulceration in mouse legs exposed to gamma rays

International Nuclear Information System (INIS)

Masuda, Kouji; Miyoshi, Makoto; Uehara, Satoru; Omagari, Junichi; Withers, H.R.

1996-01-01

To assess the dose-modifying factors for skin ulceration, the hind legs of mice were irradiated using gamma-rays of various doses in single exposures. The skin ulceration began to occur 2 months after irradiation, after early skin reactions such as wet desquamation, had healed completely. No new skin ulceration was observed more than 8 months after irradiation even though the observations were continued until 12 months post-irradiation. The ulceration dose 50 (UD50), a dose required to produce skin ulceration in from 2 to 8 months in 50% of the tested animals, was calculated for each treatment schedule. The preliminary shaving procedure reduced the UD50 dose to 0.85 that of the untreated controls. The ventral aspect of the hind leg was more radioresistant to single-dose irradiation than was to the dorsal aspect. The UD50 for the ventral aspect was 1.29 times that for the dorsal aspect when the skin had been previously shaved, and 1.46 times that for the unshaved control legs. The UD50 was 7 and 14% larger when mice were kept in the dorsal rather than the abdominal position during irradiation, for the preliminarily shaved and unshaved skin, respectively. (author)

Exposure of [Mn{sup III}{sub 6}Cr{sup III}]{sup 3+} single-molecule magnets to soft X-rays: The effect of the counterions on radiation stability

Energy Technology Data Exchange (ETDEWEB)

Helmstedt, Andreas, E-mail: andreas.helmstedt@uni-bielefeld.de [Fakultaet fuer Physik, Universitaet Bielefeld, Universitaetsstrasse 25, D-33615 Bielefeld (Germany); Sacher, Marc D.; Gryzia, Aaron; Harder, Alexander; Brechling, Armin; Mueller, Norbert; Heinzmann, Ulrich [Fakultaet fuer Physik, Universitaet Bielefeld, Universitaetsstrasse 25, D-33615 Bielefeld (Germany); Hoeke, Veronika; Krickemeyer, Erich; Glaser, Thorsten [Fakultaet fuer Chemie, Universitaet Bielefeld, Universitaetsstrasse 25, D-33615 Bielefeld (Germany); Bouvron, Samuel; Fonin, Mikhail [Fachbereich Physik, Universitaet Konstanz, Universitaetsstrasse 10, D-78457 Konstanz (Germany)

2012-01-15

Highlights: Black-Right-Pointing-Pointer [Mn{sup III}{sub 6}Cr{sup III}]{sup 3+} single-molecule magnets adsorbed on gold are investigated. Black-Right-Pointing-Pointer The oxidation state of the Mn{sup III} constituents changes under X-ray exposure. Black-Right-Pointing-Pointer The change is monitored by Mn-L{sub 3}-edge XAS. Black-Right-Pointing-Pointer Choice of anions strongly influences radiation stability of the SMM. Black-Right-Pointing-Pointer No influence of the sample morphology on radiation stability could be observed. - Abstract: X-ray absorption spectroscopy studies of the [Mn{sup III}{sub 6}Cr{sup III}]{sup 3+} single-molecule magnet deposited as a microcrystalline layer on gold substrates are presented. The oxidation state of the manganese centers changes from Mn{sup III} to Mn{sup II} due to irradiation with soft X-rays. The influence of the charge-neutralizing anions on the stability of [Mn{sup III}{sub 6}Cr{sup III}]{sup 3+} against soft X-ray exposure is investigated for the different anions tetraphenylborate (BPh{sub 4}{sup -}), lactate (C{sub 3}H{sub 5}O{sub 3}{sup -}) and perchlorate (ClO{sub 4}{sup -}). The exposure dependence of the radiation-induced reduction process is compared for [Mn{sup III}{sub 6}Cr{sup III}]{sup 3+} with the three different anions.

Usefulness of inverter type REX-650 R/F X-ray equipment

Energy Technology Data Exchange (ETDEWEB)

Kim, Jung Min; Oh, Jung Hwan [College of Health Sceince, Korea University, Seoul (Korea, Republic of)

2003-06-15

The conclusions after appraisal usefulness of Korean 30 kHz inverter type X-ray equipment which are currently used in the clinics are like those followings. The specific characters of mA, kVp, msec in the radiography keep very good accuracy and showed good waveform also under KS regulations. The output of the X-ray equipment is showed 1.7 times higher than single-phase. mA, kVp of the fluoroscopy and Sopt film exposure mA, kVp showed appropriated result under the regulations. As we consider the conversion factor of image intensifier tube used for two years, it showed pretty high results, 310 at 75 kV, and knew that the conversion factor which followed by increasing kVp increased its computations like Kim's experimentation. Those X-ray equipment showed excellent results in the appraisal while those were operating so we think that those X-ray equipment will be substitute for expensive foreign equipment in Korean domestic medical equipment in the future.

The effects of exposure to environmental factors on Heart Rate Variability: An ecological perspective

International Nuclear Information System (INIS)

Schnell, Izhak; Potchter, Oded; Epstein, Yoram; Yaakov, Yaron; Hermesh, Hagai; Brenner, Shmuel; Tirosh, Emanuel

2013-01-01

The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined in the urban space of Tel-Aviv-Jaffa. Four environmental factors were investigated: thermal and social loads; CO concentrations and noise. Levels of HRV are explained mainly by subjective social stresses, noise and CO. The most interesting result is the fact that while subjective social stress and noise increase HRV, low levels of CO are reducing HRV to some extent moderating the impact of subjective social stress and noise. Beyond the poisoning effect of CO and the fact that extremely low levels of HRV associated with high dozes of CO increase risk for life, low levels of CO may have a narcotic effect, as it is measured by HRV. The effects of thermal loads on HRV are negligible probably due to the use of behavioral means in order to neutralize heat and cold effects. -- Highlights: ► The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined. ► Previous studies measured human exposure to pollution by fixed monitoring stations. ► This study measured actual personal exposure by mini sensors. ► High level of subjective social load and noise increase HRV. ► Low levels of CO may have a narcotic effect, as it is measured by HRV. -- The research focuses on the effects of environmental factors; noise, subjective social stress, thermal load and CO on Heart Rate Variability

Measurements of indoor and outdoor natural radiation exposure rates in model houses

International Nuclear Information System (INIS)

Matsuda, Hideharu; Fukaya, Mitsuharu; Minato, Susumu

1990-01-01

Natural gamma-ray and cosmic-ray exposure rates were measured indoors and outdoors for 94 model houses of four housing centers in Nagoya to obtain basic data for estimation of the population dose. Influence of the structure of houses on indoor exposure rates and relationship between indoor and outdoor natural gamma-ray exposure rates were studied. Exposure rates were measured with a 1.5'' φ x 4'' NaI (Tl) scintillation counter and a 6''φ spherical plastic scintillation counter. The mean indoor natural gamma-ray exposure rate in ferro-concrete buildings was about 40% higher than that in fireproof wooden houses, about 60% higher than that in light-weight steel-framed buildings, in fireproof wooden houses, it was also about 10% higher than in light-weight steel-framed building. The ratio of indoor to outdoor natural gamma-ray exposure rate was found to be about 0.95±0.15, 0.77±0.10, and 0.72±0.13 for ferro-concrete buildings, fireproof wooden houses and light-weight steel-framed buildings, respectively. The mean indoor cosmic-ray exposure rate in ferro-concrete buildings was 2.8 μR/h, about 18% lower than the outdoors. The indoor cosmic-ray exposure rate in fireproof wooden houses and light-weight steel-framed buildings were 3.2 μR/h, about 6% lower than the outdoors. (author)

Evaluation of nonuniform field exposures with coupling factors

International Nuclear Information System (INIS)

Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; De Santis, Valerio; Onishi, Teruo

2015-01-01

In this study, the safety compliance for nonuniform field exposures is discussed using coupling factor concepts. The coupling factor, which is defined in the International Electrotechnical Commission 62311 standard, is extended to consider the effects of harmonics and also to apply to the specific absorption rate (for frequencies up to 30 MHz). The proposed compliance procedure is applied to and demonstrated for a prototype wireless power transfer (WPT) system with induction coupling operating at the fundamental frequency in 140 kHz band. First, measurements confirm that the perturbation of the external magnetic field strength and S 11 parameter of a one-loop antenna by a human-equivalent phantom are sufficiently small, suggesting the applicability of the magneto-quasi-static approximation to frequencies up to 30 MHz. Then, the frequency characteristics of the coupling factor are derived for the WPT system. For the prototype system that is not optimized for commercial usage, the maximum allowable transmitting power is relaxed by a factor of 23 with the proposed procedure. The contribution of the harmonics decreased the allowable transmitting power by 39%, indicating their importance for safety compliance. (paper)

Evaluation of nonuniform field exposures with coupling factors.

Science.gov (United States)

Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; De Santis, Valerio; Onishi, Teruo

2015-10-21

In this study, the safety compliance for nonuniform field exposures is discussed using coupling factor concepts. The coupling factor, which is defined in the International Electrotechnical Commission 62311 standard, is extended to consider the effects of harmonics and also to apply to the specific absorption rate (for frequencies up to 30 MHz). The proposed compliance procedure is applied to and demonstrated for a prototype wireless power transfer (WPT) system with induction coupling operating at the fundamental frequency in 140 kHz band. First, measurements confirm that the perturbation of the external magnetic field strength and S11 parameter of a one-loop antenna by a human-equivalent phantom are sufficiently small, suggesting the applicability of the magneto-quasi-static approximation to frequencies up to 30 MHz. Then, the frequency characteristics of the coupling factor are derived for the WPT system. For the prototype system that is not optimized for commercial usage, the maximum allowable transmitting power is relaxed by a factor of 23 with the proposed procedure. The contribution of the harmonics decreased the allowable transmitting power by 39%, indicating their importance for safety compliance.

Exposure to Pre- and Perinatal Risk Factors Partially Explains Mean Differences in Self-Regulation between Races.

Science.gov (United States)

Barnes, J C; Boutwell, Brian B; Miller, J Mitchell; DeShay, Rashaan A; Beaver, Kevin M; White, Norman

2016-01-01

To examine whether differential exposure to pre- and perinatal risk factors explained differences in levels of self-regulation between children of different races (White, Black, Hispanic, Asian, and Other). Multiple regression models based on data from the Early Childhood Longitudinal Study, Birth Cohort (n ≈ 9,850) were used to analyze the impact of pre- and perinatal risk factors on the development of self-regulation at age 2 years. Racial differences in levels of self-regulation were observed. Racial differences were also observed for 9 of the 12 pre-/perinatal risk factors. Multiple regression analyses revealed that a portion of the racial differences in self-regulation was explained by differential exposure to several of the pre-/perinatal risk factors. Specifically, maternal age at childbirth, gestational timing, and the family's socioeconomic status were significantly related to the child's level of self-regulation. These factors accounted for a statistically significant portion of the racial differences observed in self-regulation. The findings indicate racial differences in self-regulation may be, at least partially, explained by racial differences in exposure to pre- and perinatal risk factors.

Prevalence of sun exposure and its associated factors in southern Brazil: a population-based study.

Science.gov (United States)

Duquia, Rodrigo Pereira; Menezes, Ana Maria Baptista; Almeida, Hiram Larangeira de; Reichert, Felipe Fossati; Santos, Iná da Silva dos; Haack, Ricardo Lanzetta; Horta, Bernardo Lessa

2013-01-01

Sunlight exposure is responsible for a large number of dermatological diseases. We estimated the prevalence of sunlight exposure and its associated factors in adults from southern Brazil in a cross-sectional, population-based study. We investigated a representative sample of individuals aged ≥ 20 years (n=3,136). Sunlight exposure and its associated factors were evaluated in two distinct situations: at leisure time and at work. The time period investigated ranged from December 2004 to March 2005, comprising 120 days of the highest ultraviolet index in the urban area of the city of Pelotas, in southern Brazil. The participants were asked about sunlight exposure for at least 20 minutes between 10 A.M. and 4 P.M. The analysis was stratified by sex, and sunlight exposure was grouped into five categories. Among the 3,136 participants, prevalence of sunlight exposure at the beach was 32.8% (95% CI, 30.3 - 35.2) and 26.3% (95% CI, 24.2 28.3) among men and women, respectively. The prevalence at work was 39.8% (95% CI, 37.2 - 42.4) among men and 10.5% (95% CI, 9.1 - 12.0) among women. Age was inversely associated with sunlight exposure. Family income and achieved schooling were positively associated with sunlight exposure at leisure time and inversely associated with sunglight exposure at work. Self-reported skin color was not associated. Knowledge of any friend or relative who has been affected by skin cancer was positively associated with sunlight exposure among men at work. Despite the media campaigns on the harmful effects of excessive sunlight exposure, we found a high prevalence of sunlight exposure during a period of high ultraviolet index.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top of page What are the limitations of Bone X-ray (Radiography)? ...

Retrospective evaluation of exposure index (EI) values from plain radiographs reveals important considerations for quality improvement

Energy Technology Data Exchange (ETDEWEB)

Mothiram, Ursula; Brennan, Patrick C; Robinson, John; Lewis, Sarah J [Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Science, University of Sydney, Sydney (Australia); Moran, Bernadette [Department of Clinical Medicine, Trinity College Dublin, Dublin (Ireland); Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Science, University of Sydney, Sydney (Australia)

2013-12-15

Following X-ray exposure, radiographers receive immediate feedback on detector exposure in the form of the exposure index (EI). To identify whether radiographers are meeting manufacturer-recommended EI (MREI) ranges for routine chest, abdomen and pelvis X-ray examinations under a variety of conditions and to examine factors affecting the EI. Data on 5000 adult X-ray examinations including the following variables were collected: examination parameters, EI values, patient gender, date of birth, date and time of examination, grid usage and the presence of implant or prosthesis. Descriptive statistics were used to summarize each data set and the Mann–Whitney U test was used to determine significant differences, with P < 0.05 indicating significance for all tests. Most examinations demonstrated EI values that were outside the MREI ranges, with significantly higher median EI values recorded for female patient radiographs than those for male patients for all manufacturers, indicating higher detector exposures for all units except for Philips digital radiography (DR), where increased EI values indicate lower exposure (P = 0.01). Median EI values for out of hours radiography were also significantly higher compared with normal working hours for all technologies (P ≤ 0.02). Significantly higher median EI values were demonstrated for Philips DR chest X-rays without as compared to those with the employment of a grid (P = 0.03), while significantly lower median EI values were recorded for Carestream Health computed radiography (CR) chest X-rays when an implant or prosthesis was present (P = 0.02). Non-adherence to MREIs has been demonstrated with EI value discrepancies being dependent on patient gender, time/day of exposure, grid usage and the presence of an implant or prosthesis. Retrospective evaluation of EI databases is a valuable tool to assess the need of quality improvement in routine DR.

Retrospective evaluation of exposure index (EI) values from plain radiographs reveals important considerations for quality improvement

International Nuclear Information System (INIS)

Mothiram, Ursula; Brennan, Patrick C; Robinson, John; Lewis, Sarah J; Moran, Bernadette

2013-01-01

Following X-ray exposure, radiographers receive immediate feedback on detector exposure in the form of the exposure index (EI). To identify whether radiographers are meeting manufacturer-recommended EI (MREI) ranges for routine chest, abdomen and pelvis X-ray examinations under a variety of conditions and to examine factors affecting the EI. Data on 5000 adult X-ray examinations including the following variables were collected: examination parameters, EI values, patient gender, date of birth, date and time of examination, grid usage and the presence of implant or prosthesis. Descriptive statistics were used to summarize each data set and the Mann–Whitney U test was used to determine significant differences, with P < 0.05 indicating significance for all tests. Most examinations demonstrated EI values that were outside the MREI ranges, with significantly higher median EI values recorded for female patient radiographs than those for male patients for all manufacturers, indicating higher detector exposures for all units except for Philips digital radiography (DR), where increased EI values indicate lower exposure (P = 0.01). Median EI values for out of hours radiography were also significantly higher compared with normal working hours for all technologies (P ≤ 0.02). Significantly higher median EI values were demonstrated for Philips DR chest X-rays without as compared to those with the employment of a grid (P = 0.03), while significantly lower median EI values were recorded for Carestream Health computed radiography (CR) chest X-rays when an implant or prosthesis was present (P = 0.02). Non-adherence to MREIs has been demonstrated with EI value discrepancies being dependent on patient gender, time/day of exposure, grid usage and the presence of an implant or prosthesis. Retrospective evaluation of EI databases is a valuable tool to assess the need of quality improvement in routine DR

Restoring efficiency of hemopoietic cell transplantation in a mouse lethally irradiated by a total exposure to X rays

International Nuclear Information System (INIS)

Doria, Gino

1959-10-01

This research thesis reports the study of possibility of treatments (or restoration) of a mouse which has been submitted to a lethal dose of X rays. More particularly, the author compared the restoring efficiency of bone marrow and fetal liver injected in a mouse which had been lethally irradiated by a total exposure to X rays. He also studied the functional status of the hemopoietic graft, and the emergence of the secondary disease in mice which had been as well lethally irradiated and then restored by injection of bone marrow and fetal liver. The author then addressed the influence of the induction of immune tolerance of the host with respect to the donor on the survival of a mouse lethally irradiated and restored by homologue bone marrow [fr

The association between exposure to psychosocial work factors and mental health in older employees, a 3-year follow-up study.

Science.gov (United States)

Havermans, Bo M; Boot, Cécile R L; Hoekstra, Trynke; Houtman, Irene L D; Brouwers, Evelien P M; Anema, Johannes R; van der Beek, Allard J

2018-01-01

Unfavourable exposure to psychosocial work factors threatens older employees' mental health, and their sustained employment. This study assesses whether an improved compared to stable unfavourable and stable favourable exposure to psychosocial work factors is associated with a change in mental health in older employees at 3-year follow-up. The current study used data from the Study on Transitions in Employment, Ability and Motivation (STREAM), in workers aged 45-65 years (n = 5249). Two-year (2010-2012) exposure was assessed for psychological demands, autonomy, support, mental load, and distributive justice. Linear regression analyses were performed to compare improved exposure to unfavourable psychosocial work factors with stable unfavourable and stable favourable exposure and mental health at follow-up (2013), corrected for confounders. Analyses were stratified for age groups (45-54 and 55-65 years) and gender. In certain subgroups, stable unfavourable exposure to psychological demands, autonomy, support, and distributive justice was associated with a significantly lower mental health score than improved exposure. Stable favourable exposure to support was associated with a higher mental health score than improved support, whereas stable favourable exposure to autonomy was associated with a lower mental health score compared to improved exposure. There is a longitudinal association between changes in exposure to psychosocial work factors and mental health. Improvement in unfavourable exposure to psychosocial work factors was associated with improved mental health. This is important information for organisations that consider deploying measures to improve the psychosocial work environment of older workers.

Study of Post-Harvest Ambon Banana ( Musa acuminata ) Preservation Using X-Ray

International Nuclear Information System (INIS)

Dwijananti, P.; Handayani, L.; Marwoto, P.; Iswari, R.S.

2016-01-01

An exposure to Ambon banana ( Musa Acuminata ) samples has been done by using X-rays with current, voltage and exposure time are control parameters. This study aimed to determine storage ability of the post-harvest sample. Five samples were exposured by x-rays with the dose of (3-5) × 10 -14 Gy. The samples were stored at room temperature. Their mass and physical condition (color and smell) were evaluated every 3 days. It was found that the control sample which was not exposured by X-ray was ripe in the sixth day indicated by the yellow color and good smell of the banana. Meanwhile, the samples which were exposured by (3 - 5) × 10 -14 Gy doze of X-ray looked fresher and still had green color. These samples showed their ripening in the ninth day and their mass decrease was (12-13)% which is lower than the control sample. The preservation of banana can be done through low-dose X-ray exposure. (paper)

Micronuclei in human peripheral blood lymphocytes exposed to mixed beams of X-rays and alpha particles

Czech Academy of Sciences Publication Activity Database

Staaf, E.; Brehwens, K.; Haghdoost, S.; Nievaart, S.; Pachnerová Brabcová, Kateřina; Czub, J.; Braziewicz, J.; Wojcik, A.

2012-01-01

Roč. 51, č. 3 (2012), s. 283-293 ISSN 0301-634X Institutional research plan: CEZ:AV0Z10480505 Keywords : Micronuclei * LET * Combined exposure * Mixed beams * Alpha particles * X-rays Subject RIV: BO - Biophysics Impact factor: 1.754, year: 2012

Evaluation of medical exposure and exposure by the public in a typical scenario of examinations using mobile X-ray equipment through the Monte Carlo simulation

International Nuclear Information System (INIS)

Santos, Felipe A.; Galeano, Diego C.; Santos, William S.; Carvalho Júnior, Albérico B.

2016-01-01

In this work irradiation scenarios that simulated chest and abdomen examinations involving mobile X-ray equipment in hospitals were modeled with the purpose of calculating conversion coefficient for effective dose (CC E ), normalized to entrance surface dose (ESD), applied to patients and public individuals. These coefficients can easily be used in this practice. Patients and public individuals were represented by a pair of anthropomorphic phantoms inserted in the MCNPX 2.7.0 radiation transport code. One of the phantoms (patient) was irradiated with the direct beam simulating examinations of the chest and abdomen, each with two fields of irradiation, ideal (IF) and extrapolated (EF). Using the software SPECGEN X-ray spectra from 60 to 100 kVp at 10 kVp intervals were generated and used in this work. The other phantom (public individual) was positioned 50–200 cm from the patient. In relation to the CC E calculated in the patient, the average increase obtained between the irradiation fields was 62.4% for the chest examinations, and for the same conditions the CC E was calculated for abdomen examinations and found to be 8.0%. Increasing the distance between public individual and patient, reductions of up to 81.7% in the CC E in abdomen examinations and 83.4% in chest examinations were observed. Through the assessment of CC E of these scenarios, it is possible to measure the damages relating to this practice for both patients and public individuals. - Highlights: • A computational scenario involving mobile X-ray equipment in hospitals were modeled. • Evaluation of medical exposure and exposure by the public was made by CC E (E/ESD). • A pair of the anthropomorphic simulators was inserted into the input file MCNPX. • Analyze the influence in CC E for the different types of fields used in examinations. • Monitoring the reduction of CC E 's with increasing distance between the beds.

Self-reported noise exposure as a risk factor for long-term sickness absence

DEFF Research Database (Denmark)

Clausen, Thomas; Christensen, Karl Bang; Lund, Thomas

2009-01-01

men and women when adjusting for demographic factors and health behavior. After further adjustment for physical workload at work the association between noise exposure and sickness absence disappeared for women, but not for men. Men that reported to be exposed to loud noise between one......Self-reported noise exposure is on the rise in Denmark. Little is known, however, about the social consequences, including sickness absence, of noise exposure. The aim of this paper was to investigate the association between self-reported noise exposure and long-term sickness absence....... The association was investigated using the Cox proportional hazards model to analyze outcomes in Danish register data on the basis of Danish survey data (5357 employees aged 18-69 in 2000). The analyses showed that self-reported noise exposure was significantly associated with long-term sickness absence for both...

A Performance Evaluation of Diagnostic X-ray Unit Depends on the Hospitals Size

Energy Technology Data Exchange (ETDEWEB)

Park, Ju Hun [Kaya University, Gimhae (Korea, Republic of); Im, In Chul [Gwangju Health College University, Gwangju (Korea, Republic of); Dong, Kyung Rae [Chosun University, Gwangju (Korea, Republic of); Kang, Se Sik [College of Health Science, Catholic University of Pusan, Busan (Korea, Republic of)

2009-03-15

The purpose of this study is to measure the tube voltage, the tube current/volume, exposure time and exposure dose of diagnostic X-ray unit in each doctor offices, hospitals and general hospitals for evaluating the performance of such device, to learn the method and technology of its measurement and to suggest its importance. Research subjects were total 30 X-ray units and divided into groups of 10 X-ray units each. The tube voltage, the tube current/volume, exposure time and exposure dose were measured using percentage average error, and then reproducibility of exposure dose was measured through calculating coefficient of variation. The results are like followings; The tube voltage correctness examination showed that incongruent devices among total 30 X-ray units were 5 devices (16.7%). The tube current correctness examination showed that incongruent X-ray units were 3 devices (10.0%). The tube current volume correctness examination showed that incongruent X-ray units were 4 devices (13.3%). Finally, according to exposure time correctness examination, incongruent X-ray units were 5 devices (16.7%) and according to reproducibility examination of exposure dose, incongruent X-ray units were 7 devices (23.3%). Above results showed serious problem in performance management based on management regulation of diagnostic X-ray unit; it means that regular checkout and safety management are required, and as doing so, patients will be able to receive good quality of medical service by the reduction of radiation exposure time, image quality administration, unnecessary retake and etc. Therefore, this study suggests that the performance of diagnostic X-ray units should be checked regularly

A Performance Evaluation of Diagnostic X-ray Unit Depends on the Hospitals Size

International Nuclear Information System (INIS)

Park, Ju Hun; Im, In Chul; Dong, Kyung Rae; Kang, Se Sik

2009-01-01

The purpose of this study is to measure the tube voltage, the tube current/volume, exposure time and exposure dose of diagnostic X-ray unit in each doctor offices, hospitals and general hospitals for evaluating the performance of such device, to learn the method and technology of its measurement and to suggest its importance. Research subjects were total 30 X-ray units and divided into groups of 10 X-ray units each. The tube voltage, the tube current/volume, exposure time and exposure dose were measured using percentage average error, and then reproducibility of exposure dose was measured through calculating coefficient of variation. The results are like followings; The tube voltage correctness examination showed that incongruent devices among total 30 X-ray units were 5 devices (16.7%). The tube current correctness examination showed that incongruent X-ray units were 3 devices (10.0%). The tube current volume correctness examination showed that incongruent X-ray units were 4 devices (13.3%). Finally, according to exposure time correctness examination, incongruent X-ray units were 5 devices (16.7%) and according to reproducibility examination of exposure dose, incongruent X-ray units were 7 devices (23.3%). Above results showed serious problem in performance management based on management regulation of diagnostic X-ray unit; it means that regular checkout and safety management are required, and as doing so, patients will be able to receive good quality of medical service by the reduction of radiation exposure time, image quality administration, unnecessary retake and etc. Therefore, this study suggests that the performance of diagnostic X-ray units should be checked regularly

Prenatal exposure to lead in Spain: cord blood levels and associated factors.

Science.gov (United States)

Llop, Sabrina; Aguinagalde, Xabier; Vioque, Jesus; Ibarluzea, Jesús; Guxens, Mònica; Casas, Maribel; Murcia, Mario; Ruiz, María; Amurrio, Ascensión; Rebagliato, Marisa; Marina, Loreto Santa; Fernandez-Somoano, Ana; Tardon, Adonina; Ballester, Ferran

2011-05-01

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood). A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2μg/dL). A low percentage of cord blood samples with lead levels ≥ 2μg/dL were found (5.9%). Geometric mean and maximum were 1.06μg/dL and 19μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2μg/dL. In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels. Copyright © 2011 Elsevier B.V. All rights reserved.

A survey of chest medical X-ray doses

International Nuclear Information System (INIS)

Lomba, M.; Conha, P.G. da; Almeida, C.E. de

1996-01-01

The medical X-ray exposures due to radiological examinations are responsible for the largest contribution to the population collective dose as result of the normal use of artificial sources of radiation. The relative impact of the medical exposures to the total dose received by the population from all kinds of radiation sources varies from country to country and in some cases within the same country. The dose variations observed for a specific type of examination are in general associated to several factors i.e. the type of film-ecran combination, the choice of the appropriate physical parameters of the X-ray generator (Kvp, filament current, exposure time) and finally to the film processing conditions. At the present moment the data available in Brazil are scarce and scanty to allow a complete analyzis of this question so needed by the health authorities to justify the implementation of a quality assurance and dose reduction programs. In addition, it is desirable to establish a cost effective operation based on simple administrative concepts in order to reduce the number of films retake, then increasing the life expectancy of the equipment and the number of radiological procedures. The aim of this work was to assess the typical doses of an PA and LAT chest wall X-ray examinations in five different public hospitals (a University Hospital, a Cancer Hospital, a Navy Hospital, an Emergency Hospital and a State General Hospital), as representative of the city of Rio de Janeiro, and compare the results with the international data and recommendations available. (author)

Radiation exposure of children in pediatric radiology, Pt. 8. Radiation doses during thoracoabdominal babygram and abdominal X-ray examination of the newborn and young infants

International Nuclear Information System (INIS)

Schneider, Karl; Seidenbusch, M.C.

2010-01-01

Purpose: Reconstruction of radiation doses for the thoracoabdominal babygram and the abdomen X-ray from radiographic settings and exposure data acquired at Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007; comparison of these dose values with values reported in the literature; recommendation of a reference dose value for the thoracoabdominal babygram. Materials and Methods: The data from all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 1493 thoracoabdominal babygrams and 3632 abdomen X-rays of newborns and young infants. With the computer program PAeDOS, a specific dose reconstruction algorithm was developed. Results: the entrance dose values of thoracoabdominal babygrams and abdomen X-rays in DvHK could be reduced in the last 30 years by a factor of 5 to 8. They are far below the entrance dose values reported by other radiology departments in Europe. Nevertheless, a slight increase in the entrance doses that correlates with the introduction of a digital storage phosphor system could be observed in the last years. Conclusion: because nearly all radiosensitive body organs in early life are involved during a thoracoabdominal babygram and because of the high radiation sensitivity of newborns, thoracoabdominal babygrams should be performed in neonatology with caution. A dose value of 1.0 cGy cm 2 could serve as the actual reference dose value for the thoracoabdominal babygram of the newborn. (orig.)

Study on direct determination of uranium and efficient equilibrium factor by gamma-ray spectrometer

International Nuclear Information System (INIS)

Liu Chunkui

1990-01-01

The test principle, test set and surveying methods for conducting gamma-ray spectrometry on conveyer are presented. The conversion coefficient of the spectrometer has been found by using duallinear regression analysis of uranium and radon and their higher and lower bands of gamma-ray spectra. The efficient equilibrium factor can be quickly determined, and the direct determination of uranium in the non-equilibrium condition of uranium and radium can be made

Comprehensive study on estimation of gamma-ray exposure buildup factors for smart polymers as a potent application in nuclear industries

Science.gov (United States)

Sayyed, M. I.; AlZaatreh, M. Y.; Matori, K. A.; Sidek, H. A. A.; Zaid, M. H. M.

2018-06-01

In the present study, the exposure buildup factors (EBF) have been investigated using geometric progression (G-P) fitting method for different types of smart polymers (DMSO, PDMS, PES, PMA, PVDC, and PVDF) in the energy range of 0.015-15 MeV. From the calculations, the values of the EBF were depended on the incident photon energy, penetration depth as well as chemical composition of the polymers. In the intermediate energy region, the EBF values were reached at maximum point while in low and high energy regions, the EBF values were decreased at minimum point. The obtained results of the selected polymers have been compared in terms of EBF with Al2O3 and other common polymers such as PAN, Teflon and SR. The shielding effectiveness of the selected polymers is found to be comparable to the common polymers. The results of this work should be useful in radiation shielding applications such as in industry, medical and nuclear engineering.

Prenatal x-ray and childhood cancer in twins

International Nuclear Information System (INIS)

Harvey, E.B.

1983-01-01

In order to evaluate the causal nature of the relationship between prenatal x-ray exposure and childhood cancer, a case control study was conducted in a population of over 32,000 twins born in the state of Connecticut from 1930-1969 and followed to age 15. Thirty-two incident cancer cases were identified by linking the Connecticut Twin and Tumor registries. Each case was matched with four controls on year of birth, sex, race, and survival. Prenatal x-ray information as well as reproductive, delivery and birth data were obtained from the hospital of birth, the physician providing prenatal care, private radiology groups and interviews with hospital staff. The case control study which obtained exposure information on selected subjects found an increased risk of childhood cancer from prenatal x-ray exposure. The risk associated with radiation exposure was elevated in the following subcategories: mother with history of pregnancy loss, a gravity greater than 1, under 30 years of age, and twins weighing five pounds or more at birth. The results, though based on small numbers, strengthen the association between prenatal x-ray exposure and childhood cancer

Dose factors to calculate the radiation exposure due to radioactive waste air from nuclear facilities

International Nuclear Information System (INIS)

Brenk, H.D.; Vogt, K.J.

1977-01-01

An evaluation of the environmental impact of nuclear plants according to paragraph 45 of the Radiation Protection Directive of the Federal Republic of Germany requires the calculation of dose conversion factors indicating the correlation between the contaminated medium and individual radiation exposure. The present study is to be conceived as a contribution to discussion on this subject. For the determination of radiation exposure caused by the waste air of nuclear plants, models are being specified for computing the dose conversion factors for the external exposure pathways of β-submersion, γ-submersion and γ-radiation from contaminated ground as well as the internal exposure pathways of inhalation and ingestion, which further elaborate and improve the models previously applied, especially as far as the ingestion pathway is concerned, which distinguishes between 6 major food categories. The computer models are applied to those radionuclides which are significan for nuclear emitters, in particular nuclear light-water power stations. The results obtained for the individual exposure pathways and affected organs are specified in the form of tables. For this purpose, calculations were first of all carried out for the so-called 'reference man'. The results can be transferred to population groups with different consumption habits (e.g. vegetarians) by the application of correction factors. The models are capable of being extended with a view to covering other age groups. (orig.) [de

Stochastic risk estimation from medical x-ray diagnostic examinations, 2

International Nuclear Information System (INIS)

Hashizume, Tadashi; Maruyama, Takashi; Noda, Yutaka; Iwai, Kazuo; Tateno, Y.; Nishizawa, Kanae.

1981-01-01

The risks of genetic, leukemia and malignant diseases from medical X-ray diagnostic examinations were estimated using the frequency of radiographic and fluoroscopic exposures per diagnostic examination, child expectancy, leukemia and malignancy significant factors, and using a weighting factor determined on the basis of data concerning the cancer mortality among atomic bomb survivors in Nagasaki and of a recommendation of International Commission of Radiological Protection. The organ or tissue doses with respect to the stochastic risks were determined with ionization chambers and thermoluminescent dosimeters placed at the positions of the organs or tissues in a RANDO woman phantom which was exposed to diagnostic X-rays according to technical factors of typical radiographic and fluoroscopic examinations obtained from a nationwide survey. The resultant risks by age-group and type of radiographic and fluoroscopic examination are tabulated in terms of risk level of 10 -6 . In general, the total risk defined as the sum of genetic, leukemia and malignant risks was a high value for the X-ray diagnosis of digestive organs involving barium meal and barium enema. For example, the total risk for young age-group was 100 to 200 x 10 -6 for the X-ray diagnosis of digestive organs. The total risk from the chest radiography was lower value as compared with the risk from the X-ray diagnosis of other organs or tissues. On the contrary, the risk from the chest tomography was comparable to the risk from the diagnosis of digestive organs. The total risk decreased with increasing of age for every X-ray diagnostic examination. (author)

X-ray detector for a panoramic X-ray unit

Energy Technology Data Exchange (ETDEWEB)

Cowell, D; Ensslin, F H

1976-01-15

The discovery deals with an X-ray detector suitable for the controlling of panoramic X-ray systems. It consists of a fluorescent image screen and a semiconductor photo cell. The output signal of the detector is proportional to the intensity of the X-radiation and the response time is large enough to follow the change of amplitude of the contours of the modulated X radiation. The detector with band-pass filter regulates, via a control system, the moving rate of the X-ray source and of the film opposite it in dependence of the intensity, so that a uniform exposure is ensured.

Gas-phase organics in environmental tobacco smoke: 2. Exposure-relevant emission factors and indirect exposures from habitual smoking

Science.gov (United States)

Singer, Brett C.; Hodgson, Alfred T.; Nazaroff, William W.

Sorption of emitted gas-phase organic compounds onto material surfaces affects environmental tobacco smoke (ETS) composition and exposures indoors. We have introduced a new metric, the exposure relevant emission factor (EREF) that accounts for sorptive uptake and reemission to give the mass of individual ETS constituents available for exposure over a day in which smoking occurs. This paper describes month-long experiments to investigate sorption effects on EREFs and potential ETS exposures under habitual smoking conditions. Cigarettes were smoked in a 50-m 3 furnished room over a 3-h period 6-7 days per week, with continuous ventilation at 0.3, 0.6, or 2.1 h -1. Organic gas concentrations were measured every few days over 4-h "smoking", 10-h "post-smoking" and 10-h "background" periods. Concentration patterns of volatile ETS components including 1,3-butadiene, benzene and acrolein were similar to those calculated for a theoretical non-sorbing tracer, indicating limited sorption. Concentrations of ETS tracers, e.g. 3-ethenylpyridine (3-EP) and nicotine, and lower volatility toxic air contaminants including phenol, cresols, and naphthalene increased as experiments progressed, indicating mass accumulation on surfaces and higher desorption rates. Daily patterns stabilized after week 2, yielding a steady daily cycle of ETS concentrations associated with habitual smoking. EREFs for sorbing compounds were higher under steady cycle versus single-day smoking conditions by ˜50% for 3-EP, and by 2-3 times for nicotine, phenol, cresols, naphthalene, and methylnaphthalenes. Our results provide relevant information about potential indirect exposures from residual ETS (non-smoker enters room shortly after smoker finishes) and from reemission, and their importance relative to direct exposures (non-smoker present during smoking). Under the conditions examined, indirect exposures accounted for a larger fraction of total potential exposures for sorbing versus non-sorbing compounds

Prevalence of sun exposure and its associated factors in southern Brazil: a population-based study*

Science.gov (United States)

Duquia, Rodrigo Pereira; Menezes, Ana Maria Baptista; de Almeida, Hiram Larangeira; Reichert, Felipe Fossati; dos Santos, Iná da Silva; Haack, Ricardo Lanzetta; Horta, Bernardo Lessa

2013-01-01

BACKGROUND Sunlight exposure is responsible for a large number of dermatological diseases. OBJECTIVE We estimated the prevalence of sunlight exposure and its associated factors in adults from southern Brazil in a cross-sectional, population-based study. METHODS We investigated a representative sample of individuals aged ≥ 20 years (n=3,136). Sunlight exposure and its associated factors were evaluated in two distinct situations: at leisure time and at work. The time period investigated ranged from December 2004 to March 2005, comprising 120 days of the highest ultraviolet index in the urban area of the city of Pelotas, in southern Brazil. The participants were asked about sunlight exposure for at least 20 minutes between 10 A.M. and 4 P.M. The analysis was stratified by sex, and sunlight exposure was grouped into five categories. RESULTS Among the 3,136 participants, prevalence of sunlight exposure at the beach was 32.8% (95% CI, 30.3 - 35.2) and 26.3% (95% CI, 24.2 28.3) among men and women, respectively. The prevalence at work was 39.8% (95% CI, 37.2 - 42.4) among men and 10.5% (95% CI, 9.1 - 12.0) among women. Age was inversely associated with sunlight exposure. Family income and achieved schooling were positively associated with sunlight exposure at leisure time and inversely associated with sunglight exposure at work. Self-reported skin color was not associated. Knowledge of any friend or relative who has been affected by skin cancer was positively associated with sunlight exposure among men at work. CONCLUSION Despite the media campaigns on the harmful effects of excessive sunlight exposure, we found a high prevalence of sunlight exposure during a period of high ultraviolet index. PMID:24068126

Induction and disappearance of γH2AX foci and formation of micronuclei after exposure of human lymphocytes to ⁶⁰Co γ-rays and p(66)+ Be(40) neutrons.

Science.gov (United States)

Vandersickel, Veerle; Beukes, Philip; Van Bockstaele, Bram; Depuydt, Julie; Vral, Anne; Slabbert, Jacobus

2014-02-01

To investigate both the formation of micronuclei (MN) and the induction and subsequent loss of phosphorylated histone H2AX foci (γH2AX foci) after in vitro exposure of human lymphocytes to either (60)Co γ-rays or p(66)+ Be(40) neutrons. MN dose response (DR) curves were obtained by exposing isolated lymphocytes of 10 different donors to doses ranging from 0-4 Gy γ-rays or 0-2 Gy neutrons. Also, γH2AX foci DR curves were obtained following exposure to doses ranging from 0-0.5 Gy of either γ-rays or neutrons. Foci kinetics for lymphocytes for a single donor exposed to 0.5 Gy γ-rays or neutrons were studied up to 24 hours post-irradiation. Micronuclei yields following neutron exposure were consistently higher compared to that from (60)Co γ-rays. All MN yields were over-dispersed compared to a Poisson distribution. Over-dispersion was higher after neutron irradiation for all doses > 0.1 Gy. Up to 4 hours post-irradiation lower yields of neutron-induced γH2AX foci were observed. Between 4 and 24 hours the numbers of foci from neutrons were consistently higher than that from γ-rays. The half-live of foci disappearance is only marginally longer for neutrons compared to that from γ-rays. Foci formations were more likely to be over-dispersed for neutron irradiations. Although neutrons are more effective to induce MN, the absolute number of induced γH2AX foci are less at first compared to γ-rays. With time neutron-induced foci are more persistent. These findings are helpful for using γH2AX foci in biodosimetry and to understand the repair of neutron-induced cellular damage.

Inequities in exposure to occupational risk factors between Māori and non-Māori workers in Aotearoa New Zealand.

Science.gov (United States)

Denison, Hayley J; Eng, Amanda; Barnes, Lucy A; Cheng, Soo; 't Mannetje, Andrea; Haddock, Katharine; Douwes, Jeroen; Pearce, Neil; Ellison-Loschmann, Lis

2018-05-02

Health inequities between indigenous and non-indigenous people are well documented. However, the contribution of differential exposure to risk factors in the occupational environment remains unclear. This study assessed differences in the prevalence of self-reported exposure to disease risk factors, including dust and chemicals, physical factors and organisational factors, between Māori and non-Māori workers in New Zealand. Potential participants were sampled from the New Zealand electoral rolls and invited to take part in a telephone interview, which included questions about current workplace exposures. Logistic regression, accounting for differences in age, socioeconomic status and occupational distribution between Māori and non-Māori, was used to assess differences in exposures. In total, 2344 Māori and 2710 non-Māori participants were included in the analyses. Māori had greater exposure to occupational risk factors than non-Māori. For dust and chemical exposures, the main differences related to Māori working in occupations where these exposures are more common. However, even within the same job, Māori were more likely to be exposed to physical factors such as heavy lifting and loud noise, and organisational factors such as carrying out repetitive tasks and working to tight deadlines compared with non-Māori. This is one of the first studies internationally to compare occupational risk factors between indigenous and non-indigenous people. These findings suggest that the contribution of the occupational environment to health inequities between Māori and non-Māori has been underestimated and that work tasks may be unequally distributed according to ethnicity. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Factors influencing adherence with therapeutic sunlight exposure in older people in intermediate care facilities.

Science.gov (United States)

Durvasula, Seeta; Sambrook, Philip N; Cameron, Ian D

2012-01-01

The purpose of this study was to investigate the factors influencing low adherence with therapeutic sunlight exposure in a randomized controlled trial conducted with older people living in intermediate care facilities. The study involved participants in the FREEDOM (Falls Risk Epidemiology: Effect of vitamin D on skeletal Outcomes and other Measures) study, a randomized controlled trial of therapeutic sun exposure to reduce falls in older people in intermediate care facilities. Semi-structured interviews were conducted with thirty participants in the FREEDOM trial, and with ten sunlight officers who were employed to facilitate the sun exposure. Two focus groups involving 10 participants in the FREEDOM trial were also held at the end of the intervention period. Common themes were derived from the interview and focus group transcripts. The study showed that the perceived health benefits did not influence adherence with the sun exposure. Factors such as socializing with others and being outdoors were more important in encouraging attendance. The main barriers to adherence included the perceived inflexibility and regimentation of daily attendance, clash with other activities, unsuitable timing and heat discomfort. This study showed that providing greater flexibility and autonomy to older people in how and when they receive sun exposure is likely to improve adherence. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Epidemiological evidence for the risk of cancer from diagnostic X-rays

International Nuclear Information System (INIS)

Berrington, A.

2001-01-01

The magnitude of the risk of cancer following exposure to a single moderate or high dose of ionising radiation has been studied extensively and is quite well understood. The size of the risk of cancer from diagnostic X-rays, which are low dose, fractionated exposures and constitute the largest man-made source of radiation exposure, is much more uncertain. The aim of this thesis is to evaluate the risk of cancer to radiologists and to the population from exposure to diagnostic X-rays using various epidemiological methods. The effect of fractionated radiation exposure was investigated in a cohort of 2698 British radiologists who first registered with a radiological society after 1921. There was no evidence of an overall excess risk of cancer mortality. However, there was evidence of an increasing trend in cancer mortality with time since registration with the society (p=0.0002), such that those who had first registered more than 40 years previously had a 41% (95% Cl: 3% to 90%) excess risk compared to cancer mortality rates for all medical practitioners. Indirect estimates of the risk of cancer from diagnostic X-rays to the population were calculated with lifetable methods. Using data on the current annual frequency of diagnostic X-ray exposures to the population, estimated organ doses from these X-rays and models for the risk of cancer from the Japanese atomic bomb survivors, it was estimated that 1.5% of the lifetime risk of cancer in the U.K. population could be attributable to diagnostic X-ray exposures. In fourteen other developed countries estimates ranged from 1.6% in Finland to 8.6% in Japan. Several published case-control studies of leukaemia, brain and parotid gland tumours and thyroid cancer demonstrated significant excess risks with self-reported exposures to diagnostic X-rays. Analysis of original data from a case-control study of thyroid cancer in Kuwait also found a significant trend in risk with estimated thyroid dose from self-reported upper-body X-rays

Analyzing seasonal patterns of wildfire exposure factors in Sardinia, Italy.