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Sample records for ray dose monitoring

  1. 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

  2. Implementation of a patient dose monitoring system in conventional digital X-ray imaging: initial experiences

    Energy Technology Data Exchange (ETDEWEB)

    Heilmaier, Christina; Zuber, Niklaus; Weishaupt, Dominik [Stadtspital Triemli Zurich, Department of Radiology and Nuclear Medicine, Zurich (Switzerland)

    2017-03-15

    The purpose was to report on the initial experience after implementation of a patient dose-monitoring system in conventional X-ray imaging. A dose-monitoring system collected dose data relating to different radiographs (one projection) and studies (two or more projections). Images were acquired on digital X-ray systems equipped with flat-panel detectors. During period 1, examinations were performed in a routine fashion in 12,614 patients. After period 1, technical modifications were performed and radiographers underwent training in radiation protection. During period 2, examinations were performed in 14,514 patients, and the radiographers were advised to read dose data after each radiograph/study. Dose data were compared by means of kerma area product (KAP, gray x centimetre squared) and entrance surface air kerma (ESAK, milligray). During period 1, 13,955 radiographs and 8,466 studies were performed, and in period 2 16,090 radiographs and 10,389 studies. In period 2, KAP values for radiographs were an average of 25 % lower and for studies 7 % lower, and ESAK values for radiographs were 24 % lower and for studies 5 % lower. The reduction in KAP was significant in 8/13 radiographs and in 6/14 studies, and the reduction in ESAK was significant in 6/13 radiographs and 5/14 studies. Implementation of a patient dose-monitoring system in conventional X-ray imaging allows easy data collection, supports dose reduction efforts, and may increase radiographers' dose awareness. (orig.)

  3. Outdoor γ-ray dose rate in Shariki Village and environmental factors affecting outdoor γ-ray dose rate in IES

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2000-01-01

    Previously, we surveyed the outdoor γ-ray dose rate throughout Aomori Prefecture from 1992 to 1995, and found an annual mean dose rate of 51 nGy h -1 . Relatively high dose rates were also observed in several areas (municipalities) of the survey locations. In this study, we examined the detailed distribution of the γ-ray dose rate in one such high dose rate area, Shariki Village. Glass dosemeters were used for the monitoring of cumulative γ-ray dose rate at 10 locations in the village. The dose rate from each radioactive nuclide in the ground at the monitoring locations was measured by using an in situ γ-ray spectrometer with a Ge detector. The results obtained with the glass dosemeters showed that the γ-ray dose rates in Shariki Village varied from 49 to 55 nGy h -1 . Although the dose rates were generally higher than the mean dose in Aomori Prefecture (1992-1995), the rates were lower than other high dose rate areas which had already been measured. The in situ γ-ray spectrometry revealed that these relatively high dose rates were mainly caused by 40 K and Th series radionuclides in the village. The effect of meteorological conditions on the γ-ray dose rate was studied at a monitoring station in the IES site. The dose rate was continuously recorded by a DBM NaI(Tl) scintillation detector system. The mean dose rate obtained when precipitation was sensed was 27 nGy h -1 and higher than when no precipitation was sensed (25 nGy h -1 ). (author)

  4. Outdoor γ-ray dose rate in Mutsu city and environmental factors affecting outdoor γ-ray dose rate in IES

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2001-01-01

    Previously, we surveyed outdoor γ-ray dose rates throughout Aomori Prefecture from 1992 to 1995, and found a mean annual dose rate of 28 nGy h -1 . Relatively high dose rates were also observed in several areas (municipalities) of the survey locations. In this study, we examined the detailed distribution of the γ-ray dose rate in one such high dose rate area, Mutsu City. Glass dosemeters were used for the monitoring of cumulative γ-ray dose rate at 10 locations in the city. The dose rate from each radioactive nuclide in the ground at the monitoring locations was measured by using an in situ γ-ray spectrometer with a Ge detector. The results obtained with the glass dosemeters showed that the γ-ray dose rates in Mutsu City varied from 17 to 32 nGy h -1 . Although the dose rates were almost the same as the mean dose in Aomori Prefecture (1992-1995), the rates were lower than other high dose rate areas which had already been measured. The in situ γ-ray spectrometry revealed that these relatively high dose rates were mainly caused by 40 K and Th series radionuclides in the local ground. The effect of meteorological conditions on the γ-ray dose rate was studied at a monitoring station in the IES site. The dose rate was continuously recorded by a DBM NaI(Tl) scintillation detector system. The mean dose rate obtained when precipitation was sensed was 26 nGy h -1 and higher than when no precipitation was sensed (24 nGy h -1 ). (author)

  5. TLD personnel monitoring dose estimation- extending the upper limit of the dose range

    International Nuclear Information System (INIS)

    Popli, K.L.; Sathian, Deepa; Divakaran, T.; Massand, O.P.

    2001-01-01

    TLD personnel monitoring was introduced in the year 1975 in India and at present nearly 41,000 radiation workers are being monitored by 13 monitoring laboratories all over India. The BARC- TLD being used for personnel monitoring is based on CaSO 4 :Dy embedded in PTFE and semi-automatic TL reader using hot N 2 Gas for heating the dosimeters. This reader has the range to measure γ dose from ten μSv to 3 μSv and x-ray dose form 1 μ Sv to 0.3 Sv due to the higher sensitivity of CaSO 4 : Dy to lower energy photons (20keV-50 keV) generated by diagnostic x-ray units. The x-ray radiation workers are at present nearly 35% of the total radiation workers monitored and this number is expected to grow as more and more number of x-ray workers are covered under this service. The upper limit of the x-ray dose range of the instrument is 0.3 Sv, whereas in the past one year it has been observed that at least 25% of the total overexposures reported in case of x-ray workers have recorded the dose more than 0.3 Sv. This paper presents the technique developed to extend the upper limit of the range from 0.3 Sv to 1 Sv for x-rays and 10 Sv for γ rays

  6. A review of radiology staff doses and dose monitoring requirements

    International Nuclear Information System (INIS)

    Martin, C. J.

    2009-01-01

    Studies of radiation doses received during X-ray procedures by radiology, cardiology and other clinical staff have been reviewed. Data for effective dose (E), and doses to the eyes, thyroid, hands and legs have been analysed. These data have been supplemented with local measurements to determine the most exposed part of the hand for monitoring purposes. There are ranges of 60-100 in doses to individual tissues reported in the literature for similar procedures at different centres. While ranges in the doses per unit dose-area product (DAP) are between 10 and 25, large variations in dose result from differences in the sensitivity of the X-ray equipment, the type of procedure and the operator technique, but protection factors are important in maintaining dose levels as low as possible. The influence of shielding devices is significant for determining the dose to the eyes and thyroid, and the position of the operator, which depends on the procedure, is the most significant factor determining doses to the hands. A second body dosemeter worn at the level of the collar is recommended for operators with high workloads for use in assessment of effective dose and the dose to the eye. It is proposed that the third quartile values from the distributions of dose per unit DAP identified in the review might be employed in predicting the orders of magnitude of doses to the eye, thyroid and hands, based on interventional operator workloads. Such dose estimates could be employed in risk assessments when reviewing protection and monitoring requirements. A dosemeter worn on the little finger of the hand nearest to the X-ray tube is recommended for monitoring the hand. (authors)

  7. Electrical behavior research of silicon photo-cell used in online monitoring absorbed dose rate of γ-ray

    International Nuclear Information System (INIS)

    Yang Guixia; Li Xiaoyan; Fu Lan; Wu Wenhao; An You; Zeng Fansong

    2015-01-01

    The real-time online monitoring system for γ-ray absorbed dose rate was established to study the relationship between the photocurrent of semi-conductive silicon photo-cell BBZSGD-4 and γ-ray absorbed dose rate under the open circuit. The radioactive experiments in "6"0Co γ radiation field show that photo-cell BBZSGD-4 has good response to "6"0Co γ-ray, and their relationship accords with the linear law. The photocurrent of photo-cell can be up to 1.26 μA when the absorbed dose rate is 94.54 Gy/min. The relationship between photocurrent and the absorbed dose accords with exponential law when absorbed dose rate is 50 Gy/min, and the attenuation of photocurrent is 1% when the absorbed dose is 5445.8 Gy. Thus photo-cell BBZSGD-4 has the potential to be a real-time detector to detect low absorbed dose rate in "6"0Co γ radiation field. (authors)

  8. MONITORING OF INDIVIDUAL DOSES FOR MEDICAL WORKERS OF DENTAL POLYCLINIC’S X-RAY ROOMS IN DUSHANBE, THE REPUBLIC OF TADJIKISTAN

    Directory of Open Access Journals (Sweden)

    N. U. Hakimova

    2016-01-01

    Full Text Available The article presents the data and analyses of personnel’s average annual external exposure doses monitoring via the thermoluminescent dosimetry method used for X-ray radiological personnel in dental polyclinics of Dushanbe, Tadjikistan Republic over a 5-year period ( 2010–2014 . Out of 42 registered medical institutions dental polyclinics amounted up to only just 14%. For this work thermoluminescent dosimeters were used ( with LiF: Mg, Ti with the thermoluminescent dosimetric installation “ Harshaw – 4500” as the reader device. Monitoring results comparison of individual dose equivalent Hp ( 10 values was conducted for two groups of medical workers: medical doctors and X-ray lab technicians. It is demonstrated that radiological technicians’ professional exposure doses are on the average by 23% higher than those for medical doctors.The average individual exposure doses over the above indicated period amount to 0,93 mSv and 1,3 mSv for doctors and X-ray lab technicians, respectively, and are in the range from 0,45 mSv to 2,39 mSv. The doses include contribution from the natural background. The values of doses recorded for the personnel in dental polyclinic correspond to those recorded for the workers in the routine X-ray rooms.

  9. Personnel monitoring for beta rays

    International Nuclear Information System (INIS)

    Piesch, E.; Johns, T.F.

    1983-01-01

    The practical considerations which have to be taken into account in the design of personnel monitors intended to measure doses resulting from exposure to beta rays are discussed. These include the measurement of doses in situations involving either fairly uniform or non-uniform irradiation and of doses to the male gonads. (UK)

  10. Fourth IRMF comparison of calibrations of portable gamma-ray dose- rate monitors 2001-2002 Ionising radiation

    CERN Document Server

    Lewis, V E

    2002-01-01

    The Ionising Radiations Metrology Forum (IRMF) organised a fourth comparison of calibrations of gamma-ray dose-rate monitors in which fifteen establishments in the UK participated. The exercise involved the circulation of three gamma-ray monitors for calibration in the fields produced using sup 1 sup 3 sup 7 Cs, sup 2 sup 4 sup 1 Am and sup 6 sup 0 Co. The instruments used were an Electra with MC 20 probe, a Mini-Instruments Mini-rad 1000 and a Siemens electronic personal dosemeter Mk 2 (EPD). The responses relative to 'true' dose equivalent rate were calculated by the individual participants and submitted to the for analysis along with details of the facilities and fields employed. Details of the estimated uncertainties were also reported. The results are compared and demonstrate generally satisfactory agreement between the participating establishments. However, the participants' treatment of uncertainties needs improvement and demonstrates a need for guidance in this area.

  11. 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.)

  12. Cosmic-ray contribution in measurement of environmental gamma-ray dose

    International Nuclear Information System (INIS)

    Nagaoka, Kazunori; Honda, Kouichirou; Miyano, Keiji

    1996-01-01

    Nowadays several kinds of dosimeters are being used for environmental gamma-ray monitoring. However the results measured by those instruments are not always in good agreement. It may be caused from the different characteristics of dosimeters. In particular the different responses of the instruments to cosmic-rays give significant influence on the results. Environmental radiation measurements at various altitudes on Mt. Fuji were carried out using a scintillation spectrometer with 3''φ spherical NaI(Tl), a pressurized ionization chamber (PIC), an air-equivalent ionization chamber (IC), thermoluminescence dosimeters (TLD), radiophotoluminescence glass dosimeters (RPLD) and NaI(Tl) scintillation survey meters so that the response characteristics of these instruments to cosmic-rays could be clarified. Cosmic-ray contributions for all instruments were correlated with counting rate over 3 MeV by the spectrometer. Each contribution can be estimated by measurement of the counting rate. Conversion factors (nGy/h/cpm) for IC, PIC, TLD, RPLD and NaI survey meters (TCS166 and TCS121C) were 0.33, 0.32, 0.25, 0.24, 0.06 and -0.01, respectively. Self-doses of these instruments were estimated by measurements at Nokogiriyama facilities of the Institute for Cosmic Ray Research, University of Tokyo. Self-doses for TLD and RPLD were approximately 6 nGy/h. The self dose effect should be taken into consideration in environmental dose measurements. These data are expected to be useful in estimating the cosmic-ray contribution and self-dose in the measurement of environmental gamma-ray dose. (author)

  13. Outdoor γ-ray dose rate in Ajigasawa Town and environmental factors affecting it in IES

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shunichi; Sakurai, Naoyuki; Koyama, Kenji

    1999-01-01

    We surveyed the outdoor γ-ray dose rate throughout Aomori Prefecture from 1991 to 1995, and found an annual mean dose rate of 46 nGy h -1 . Relatively high dose rates were also observed in several areas (municipalities) of the survey locations. In this study, we examined the detailed distribution of the γ-ray dose rate in one such high dose rate area, Ajigasawa Town. Glass dosimeters were used for the monitoring of cumulative γ-ray dose rate at 10 locations in the town. The dose rate from each radioactive nuclide in the ground at the monitoring locations was measured by using an in situ γ-ray spectrometer with a Ge detector. The results obtained with the glass dosimeters showed that the γ-ray dose rates in Ajigasawa Town varied from 48 to 57 nGy h -1 . Although the dose rates were generally higher than the mean dose in Aomori Prefecture (1992-1995), the rates were lower than other high dose rate areas which had already been measured. The in situ γ-ray spectrometry revealed that these relatively high dose rates were mainly caused by 40 K and Th series radionuclides in the town. The effect of meteorological conditions on the γ-ray dose rate was studied at a monitoring station in IES. The dose rate was continuously recorded by a DBM NaI(Tl) scintillation detector system. The mean dose rate obtained when precipitation was sensed was 27 nGy h -1 and higher than when no precipitation was sensed (23 nGy h -1 ). (author)

  14. A dose monitoring system for dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chena; Lee, Sam Sun; Kim, Jo Eun; Huh, Kyung Hoe; Yi, Woo Jin; Heo, Min Suk; Choi, Soon Chul [Dept. of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Symkhampha, Khanthaly [Dept. of Oral and Maxillofacial Radiology, Department of Basic Science, Faculty of Dentistry, University of Health Sciences, Vientiane (Lao People' s Democratic Republic); Lee, Woo Jin [Dept. of Interdisciplinary Program in Radiation, Applied Life Sciences Major, College of Medicine, BK21, and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Yeom, Heon Young [School of Computer Science Engineering, Seoul National University, Seoul (Korea, Republic of)

    2016-06-15

    The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose.

  15. A dose monitoring system for dental radiography

    International Nuclear Information System (INIS)

    Lee, Chena; Lee, Sam Sun; Kim, Jo Eun; Huh, Kyung Hoe; Yi, Woo Jin; Heo, Min Suk; Choi, Soon Chul; Symkhampha, Khanthaly; Lee, Woo Jin; Yeom, Heon Young

    2016-01-01

    The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose

  16. Development of a real-time extremity dose monitor for personnel in interventional radiology

    International Nuclear Information System (INIS)

    Ban, Nobuhiko; Kusama, Tomoko; Adachi, Akiko

    2000-01-01

    Protection of personnel in interventional radiology is one of the most important issues of radiological protection in medicine. Fluoroscopically guided interventional procedures require the operation near X-ray beam, which brings a considerable hand exposure to the operators. For the purpose of effectual control of their extremity doses, we have developed a real-time extremity dose monitor which is worn on a strap around the wrist. The monitor consists of a silicon semiconductor detector, thin lithium battery and a waterproof frame with a four-digit LED display. Experiment was carried out to examine a response of the monitor to diagnostic X-rays. A practical test was also performed to evaluate usability in the actual interventional procedures. In the experiment, the extremity dose monitor was placed on an arm phantom and exposed to diagnostic X-rays. Readings of the monitor were compared to those of Capintec PS-033 shallow chamber. The monitor was highly sensitive to diagnostic X-rays. It showed a linear response down to doses of a few tens of microsieverts. For high dose-rate exposure, however, a slight decrease in the response was observed, about 10% of counting loss for 80 kV, 40 mA X-ray at one meter from the focus. With regard to energy dependence, variation was within 20% for 60 to 100 kV X-rays. The monitor showed a good angular response in general, except lateral geometry facing the far side from a detector center. In the practical test, hand exposures of medical staff were measured with the extremity dose monitor. They were also asked to fill in a questionnaire regarding size and weight of the monitor, clarity of the display and usefulness. The subjects consisted of physicians, technicians and nurses who engaged in angiography, PTCD, CT-biopsy, barium enema and so on. The readings of the monitor were less than 1 mSv in most cases while 93 mSv was recorded in an extreme case due to direct-beam exposure. In some cases, TLD rings were used together with the

  17. Development of a real-time extremity dose monitor for personnel in interventional radiology

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Nobuhiko; Kusama, Tomoko [Oita University of Nursing and Health Sciences, Oita (Japan); Adachi, Akiko [Oita Medical University, Oita (JP)] [and others

    2000-05-01

    Protection of personnel in interventional radiology is one of the most important issues of radiological protection in medicine. Fluoroscopically guided interventional procedures require the operation near X-ray beam, which brings a considerable hand exposure to the operators. For the purpose of effectual control of their extremity doses, we have developed a real-time extremity dose monitor which is worn on a strap around the wrist. The monitor consists of a silicon semiconductor detector, thin lithium battery and a waterproof frame with a four-digit LED display. Experiment was carried out to examine a response of the monitor to diagnostic X-rays. A practical test was also performed to evaluate usability in the actual interventional procedures. In the experiment, the extremity dose monitor was placed on an arm phantom and exposed to diagnostic X-rays. Readings of the monitor were compared to those of Capintec PS-033 shallow chamber. The monitor was highly sensitive to diagnostic X-rays. It showed a linear response down to doses of a few tens of microsieverts. For high dose-rate exposure, however, a slight decrease in the response was observed, about 10% of counting loss for 80 kV, 40 mA X-ray at one meter from the focus. With regard to energy dependence, variation was within 20% for 60 to 100 kV X-rays. The monitor showed a good angular response in general, except lateral geometry facing the far side from a detector center. In the practical test, hand exposures of medical staff were measured with the extremity dose monitor. They were also asked to fill in a questionnaire regarding size and weight of the monitor, clarity of the display and usefulness. The subjects consisted of physicians, technicians and nurses who engaged in angiography, PTCD, CT-biopsy, barium enema and so on. The readings of the monitor were less than 1 mSv in most cases while 93 mSv was recorded in an extreme case due to direct-beam exposure. In some cases, TLD rings were used together with the

  18. Effects of X-Ray Dose On Rhizosphere Studies Using X-Ray Computed Tomography

    Science.gov (United States)

    Zappala, Susan; Helliwell, Jonathan R.; Tracy, Saoirse R.; Mairhofer, Stefan; Sturrock, Craig J.; Pridmore, Tony; Bennett, Malcolm; Mooney, Sacha J.

    2013-01-01

    X-ray Computed Tomography (CT) is a non-destructive imaging technique originally designed for diagnostic medicine, which was adopted for rhizosphere and soil science applications in the early 1980s. X-ray CT enables researchers to simultaneously visualise and quantify the heterogeneous soil matrix of mineral grains, organic matter, air-filled pores and water-filled pores. Additionally, X-ray CT allows visualisation of plant roots in situ without the need for traditional invasive methods such as root washing. However, one routinely unreported aspect of X-ray CT is the potential effect of X-ray dose on the soil-borne microorganisms and plants in rhizosphere investigations. Here we aimed to i) highlight the need for more consistent reporting of X-ray CT parameters for dose to sample, ii) to provide an overview of previously reported impacts of X-rays on soil microorganisms and plant roots and iii) present new data investigating the response of plant roots and microbial communities to X-ray exposure. Fewer than 5% of the 126 publications included in the literature review contained sufficient information to calculate dose and only 2.4% of the publications explicitly state an estimate of dose received by each sample. We conducted a study involving rice roots growing in soil, observing no significant difference between the numbers of root tips, root volume and total root length in scanned versus unscanned samples. In parallel, a soil microbe experiment scanning samples over a total of 24 weeks observed no significant difference between the scanned and unscanned microbial biomass values. We conclude from the literature review and our own experiments that X-ray CT does not impact plant growth or soil microbial populations when employing a low level of dose (<30 Gy). However, the call for higher throughput X-ray CT means that doses that biological samples receive are likely to increase and thus should be closely monitored. PMID:23840640

  19. Real-time personal dose monitoring and management system

    International Nuclear Information System (INIS)

    Zhang Zhiyong; Cheng Chang; Yang Huating; Liu Zhengshan; Deng Changming; Li Mei

    2000-01-01

    This paper mainly describes a real-time personal dose monitoring and management system. The system is composed of three parts that include SDM-98 semiconductor detector personal dosimeters, Data Readers and a Management System Software. It can be used for personal dose monitoring and management and other controlling actions in a radioactive controlled area. Adopting semiconductor detector and microcontroller, SDM-98 Personal Dosimeter is used to measure personal accumulated dose equivalent and dose rate caused by X-ray and Gamma ray. The results can be read directly on LCD. All the data stored in dosimeter can be transmitted into a data reader by infrared optical link. The alarm threshold can be adjusted successively in whole range of dose or dose rate. The Data Reader is an intelligent interface between the dosimeter and master computer. The data received from dosimeter will be sent to a master computer through RS-232 serial interface. According to the master computer's order, the Data Reader can turn on the dosimeter's power at entrance and shutdown it at exit. The Management System Software which written by Visual BASIC 5.0 runs on MS Win95. All the measuring data from dosimeters can be analyzed and treated according to requirements and stored in database. Therefore, some figures and tables relative to dose or rate can be shown on screen or printed out. (author)

  20. Response of radiation monitoring labels to gamma rays and electrons

    DEFF Research Database (Denmark)

    Rahim, F. Abdel; Miller, Arne; McLaughlin, W.L.

    1985-01-01

    or location has been irradiated to high doses. Among labels available worldwide, a few are suitable for indicating absorbed dose regions of slightly less than 104 Gy (monitoring high dose ranges (i.e., sterilization dose levels of > 104 Gy or > 1 Mrad), and in some cases......, and differences in dose rate and radiation type (gamma rays and electron beams) were made on 15 kinds of labels. The results show that, for many types of indicators, diverse effects may give misleading conclusions unless countermeasures are taken. For example, some of the most commonly used labels, which contain...... permit somewhat more precise discrimination of dose levels, and may sometimes be useful for monitoring differences in local dose distributions or area monitoring of radiation damage probabilities around particle accelerators or large radionuclide sources....

  1. Patient and population doses of x-ray diagnostics in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Rannikko, S; Karila, K T.K.; Toivonen, M

    1997-09-01

    Periodic surveys of patient and population doses are important because of the large contribution of x-ray diagnostics to the artificial population dose. Measured entrance surface doses and dose-area products are the main quantities used for monitoring patient doses in hospitals, and most population dose studies have been derived from these quantities and from the frequences of x-ray examinations. This study is based on the radiation, exposure geometry, and patient parameters recorded by experienced radiographers and postgraduated students. The software used in the work (ODS-60 of Rados Technology) suits the determination of effective and organ doses from such detailed data using a human-like patient phantom which can be adapted for sex and size. The program, together with the very detailed input data, made it possible to determine organ equivalent and effective doses for complicated dynamic x-ray examinations and interventions in more detail than in previous studies. Collective organ and effective doses were derived for 50 examination types. The annual collective dose from diagnostic x-ray examinations in 1994 was 0.5 mSv per capita in Finland. The five groups of examinations or examinations that had greatest contributions to the collective dose were CT, barium enema: double contrast, lumbar spine, carotid angiography, and intestinal transit. Together they represented for about 60 % of the total dose. The highest dose-area products (about 2000 Gy cm{sup 2}) were obtained from certain angiographic and interventional examinations. A literature survey showed that Finland patient doses are at the same average level as in other countries of a high standard of health care. (orig.). 125 refs.

  2. Patient and population doses of x-ray diagnostics in Finland

    International Nuclear Information System (INIS)

    Rannikko, S.; Karila, K.T.K.; Toivonen, M.

    1997-09-01

    Periodic surveys of patient and population doses are important because of the large contribution of x-ray diagnostics to the artificial population dose. Measured entrance surface doses and dose-area products are the main quantities used for monitoring patient doses in hospitals, and most population dose studies have been derived from these quantities and from the frequences of x-ray examinations. This study is based on the radiation, exposure geometry, and patient parameters recorded by experienced radiographers and postgraduated students. The software used in the work (ODS-60 of Rados Technology) suits the determination of effective and organ doses from such detailed data using a human-like patient phantom which can be adapted for sex and size. The program, together with the very detailed input data, made it possible to determine organ equivalent and effective doses for complicated dynamic x-ray examinations and interventions in more detail than in previous studies. Collective organ and effective doses were derived for 50 examination types. The annual collective dose from diagnostic x-ray examinations in 1994 was 0.5 mSv per capita in Finland. The five groups of examinations or examinations that had greatest contributions to the collective dose were CT, barium enema: double contrast, lumbar spine, carotid angiography, and intestinal transit. Together they represented for about 60 % of the total dose. The highest dose-area products (about 2000 Gy cm 2 ) were obtained from certain angiographic and interventional examinations. A literature survey showed that Finland patient doses are at the same average level as in other countries of a high standard of health care. (orig.)

  3. Dose evaluation for digital X-ray imaging of premature neonates

    International Nuclear Information System (INIS)

    Minkels, T.J.M.; Jeukens, C.R.L.P.N.; Andriessen, P.; Van der Linden, A.N.; Dam, A.J.; Van Straaten, H.L.M.; Cottaar, E.J.E.; Van Pul, C.

    2017-01-01

    X-ray radiography is a commonly used diagnostic method for premature neonates. However, because of higher radiosensitivity and young age, premature neonates are more sensitive to the detrimental effects of ionising radiation. Therefore, it is important to monitor and optimise radiation doses at the neonatal intensive care unit (NICU). The number of X-ray examinations, dose area product (DAP) and effective doses are evaluated for three Dutch NICUs using digital flat panel detectors. Thorax, thorax abdomen and abdomen protocols are included in this study. Median number of examinations is equal to 1 for all three hospitals. Median DAP ranges between 0.05 and 1.02 μGy m2 for different examination types and different weight categories. These examinations result in mean effective doses between 4 ± 4 and 30 ± 10 μSv per examination. Substantial differences in protocols and doses can be observed between hospitals. This emphasises the need for up-to-date reference levels formulated specifically for premature neonates. (authors)

  4. Dose profile monitoring with carbon ions by means of prompt-gamma measurements

    Energy Technology Data Exchange (ETDEWEB)

    Testa, E. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France)], E-mail: e.testa@ipnl.in2p3.fr; Bajard, M.; Chevallier, M.; Dauvergne, D.; Le Foulher, F. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France); Freud, N.; Letang, J.M. [Institut National des Sciences Appliquees de Lyon, Laboratoire de Controle Non-Destructif par Rayonnements Ionisants (France); Poizat, J.C.; Ray, C.; Testa, M. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France)

    2009-03-15

    A key point in the quality control of ion therapy is real-time monitoring and imaging of the dose delivered to the patient. Among the possible signals that can be used to make such a monitoring, prompt gamma-rays issued from nuclear fragmentation are possible candidates, provided the correlation between the emission profile and the primary beam range can be established. By means of simultaneous energy and time-of-flight discrimination, we could measure the longitudinal profile of the prompt gamma-rays emitted by 73 MeV/u carbon ions stopping inside a PMMA target. This technique allowed us to minimize the shielding against neutrons and scattered gamma rays, and to find a good correlation between the prompt-gamma profile and the ion range. This profile was studied as a function of the observation angle. By extrapolating our results to higher energies and realistic detection efficiencies, we showed that prompt gamma-ray measurements make it feasible to control in real time the longitudinal dose during ion therapy treatments.

  5. Single-shot beam-position monitor for x-ray free electron laser

    Science.gov (United States)

    Tono, Kensuke; Kudo, Togo; Yabashi, Makina; Tachibana, Takeshi; Feng, Yiping; Fritz, David; Hastings, Jerome; Ishikawa, Tetsuya

    2011-02-01

    We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 μm by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

  6. The current situation of personal dose monitoring in Chinese medicine radiation and undamaged detection

    International Nuclear Information System (INIS)

    Zhang Liangan; Zhang Wenyi; Yuan Shuyu; Song Shijun; Chang Hexin; Sun Kai

    1993-01-01

    The situation of personal dose monitoring in γ(X) external exposure in China is mainly outlined. Thermoluminescent dosimetry (TLD) was adopted for personal dose measurement of the radiation workers. The computer software and data base for the work have been developed and applied. National intercomparison of TLD, monitoring control of personal dose monitoring in field, and technical training were carried out for quality control. In China, the dominant occupational exposures is X-ray diagnosis and it increases year by year, the highest values is about 22.6%. The highest values of annual collective dose and annual average of individual dose (AAID) are 272.8 man·Sv and 3.21 mSv respectively. This work shows that the fraction of the population receiving high dose is decreased with time rapidly. The situation for whole occupational exposures is also described. (3 tabs.)

  7. X-raying with low dose irradiation

    International Nuclear Information System (INIS)

    Malevich, E.E.; Kisel, E.M.; Shpita, I.D.; Lazovsky, A.S.

    2001-01-01

    With the purpose of the improvement of diagnostics quality and reduction of beam load on a patient in modern x-ray devices pulse x-raying is applied. It is based on the using of radiation pulses with various frequencies of intervals between them instead of continuous radiation. At pulse x-raying with the net control the principle of filling of an interval is used, when the information about the image, received with the last pulse, get into memory and is displayed before occurrence of other pulse. It creates impression of the continuous image even at low frequency of pulses. Due to the unique concept of the simultaneous (double) control, all of 3 parameters, which define the quality of the image (pressure(voltage), force of a current and length of a pulse), are adjusted automatically at each pulse, thus optimum adaptation to varied thickness of object during dynamic researches occurs. At x-raying pulse the presence of a free interval from x-ray radiation between two pulses results in the decrease of a radiation dose. Pulsing occurs some times per one second with equal intervals between pulses. Thus, the degree of decrease irradiation dose depends on duration of a pause between pulses. On the screen the image of last pulse before occurrence of the following is kept and repeats. The principle of x-raying pulse was realized in system Grid Controlled Fluoroscopy by the firm 'Philips Medi zin Systeme'. In the x-ray tube of this system inclusion and de energizing of radiation occurs directly on a source. Electron cloud is broken off by the special grid, which is located between the cathode and the anode and operates as a barrier. Thus the tube continues to be energized. In usual devices for pulses formation is used generator pulsation system, which at increase and attenuation of a x-ray pulse results in occurrence of the increasing and fading radiation which are not participating in the formation of the image, but creating beam load on the patient and the personnel. Thus

  8. SU-E-I-10: Automatic Monitoring of Accumulated Dose Indices From DICOM RDSR to Improve Radiation Safety in X-Ray Angiography

    International Nuclear Information System (INIS)

    Omar, A; Bujila, R; Nowik, P; Karambatsakidou, A

    2014-01-01

    Purpose: To investigate the potential benefits of automatic monitoring of accumulated patient and staff dose indicators, i.e., CAK and KAP, from DICOM Radiation Dose Structured Reports (RDSR) in x-ray angiography (XA). Methods: Recently RDSR has enabled the convenient aggregation of dose indices and technique parameters for XA procedures. The information contained in RDSR objects for three XA systems, dedicated to different types of clinical procedures, has been collected and aggregated in a database for over one year using a system developed with open-source software at the Karolinska University Hospital. Patient weight was complemented to the RDSR data via an interface with the Hospital Information System (HIS). Results: The linearly approximated trend in KAP over a time period of a year for cerebrovascular, pelvic/peripheral vascular, and cardiovascular procedures showed a decrease of 12%, 20%, and 14%, respectively. The decrease was mainly due to hardware/software upgrades and new low-dose imaging protocols, and partially due to ongoing systematic radiation safety education of the clinical staff. The CAK was in excess of 3 Gy for 15 procedures, and exceeded 5 Gy for 3 procedures. The dose indices have also shown a significant dependence on patient weight for cardiovascular and pelvic/peripheral vascular procedures; a 10 kg shift in mean patient weight can result in a dose index increase of 25%. Conclusion: Automatic monitoring of accumulated dose indices can be utilized to notify the clinical staff and medical physicists when the dose index has exceeded a predetermined action level. This allows for convenient and systematic follow-up of patients in risk of developing deterministic skin injuries. Furthermore, trend analyses of dose indices over time is a valuable resource for the identification of potential positive or negative effects (dose increase/decrease) from changes in hardware, software, and clinical work habits

  9. SU-E-I-10: Automatic Monitoring of Accumulated Dose Indices From DICOM RDSR to Improve Radiation Safety in X-Ray Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Omar, A; Bujila, R; Nowik, P; Karambatsakidou, A [Karolinska University Hospital, Stockholm (Sweden)

    2014-06-01

    Purpose: To investigate the potential benefits of automatic monitoring of accumulated patient and staff dose indicators, i.e., CAK and KAP, from DICOM Radiation Dose Structured Reports (RDSR) in x-ray angiography (XA). Methods: Recently RDSR has enabled the convenient aggregation of dose indices and technique parameters for XA procedures. The information contained in RDSR objects for three XA systems, dedicated to different types of clinical procedures, has been collected and aggregated in a database for over one year using a system developed with open-source software at the Karolinska University Hospital. Patient weight was complemented to the RDSR data via an interface with the Hospital Information System (HIS). Results: The linearly approximated trend in KAP over a time period of a year for cerebrovascular, pelvic/peripheral vascular, and cardiovascular procedures showed a decrease of 12%, 20%, and 14%, respectively. The decrease was mainly due to hardware/software upgrades and new low-dose imaging protocols, and partially due to ongoing systematic radiation safety education of the clinical staff. The CAK was in excess of 3 Gy for 15 procedures, and exceeded 5 Gy for 3 procedures. The dose indices have also shown a significant dependence on patient weight for cardiovascular and pelvic/peripheral vascular procedures; a 10 kg shift in mean patient weight can result in a dose index increase of 25%. Conclusion: Automatic monitoring of accumulated dose indices can be utilized to notify the clinical staff and medical physicists when the dose index has exceeded a predetermined action level. This allows for convenient and systematic follow-up of patients in risk of developing deterministic skin injuries. Furthermore, trend analyses of dose indices over time is a valuable resource for the identification of potential positive or negative effects (dose increase/decrease) from changes in hardware, software, and clinical work habits.

  10. Development of a Real-time Hand Dose Monitor for Personnel in Interventional Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Ban, N.; Nakaoka, H.; Haruta, R.; Murakami, Y.; Kubo, T.; Maeda, T.; Kusama, T

    2001-07-01

    Medical procedures denoted as interventional radiology require operation near an X ray beam, which brings high dose exposures to the operators' hands. For the effectual control of their extremity doses, a prototype of a real-time wrist dosemeter has been developed, hand dose monitor (HDM), based on a single silicon detector. Experiments were performed to test its response to diagnostic X rays. The HDM was highly sensitive and showed a linear response down to doses of a few tens of microsieverts. Though dose rate, energy and angular dependence of the response were observed in some extreme conditions, the HDM was proved to be of practical use if it was appropriately calibrated. Since an HDM enables personnel to check their hand doses on a real-time basis, it would enable medical staff to control the exposure themselves. (author)

  11. Determination of Entrance Skin Doses and Organ Doses for Medical X Ray Examinations

    International Nuclear Information System (INIS)

    Tung, C.J.; Cheng, C.Y.; Chao, T.C.; Tsai, H.Y.

    1999-01-01

    A national survey of patient doses for diagnostic X ray radiographs is planned in Taiwan. Entrance skin doses and organ doses for all installed X ray machines will be investigated. A pilot study has been carried out for the national survey to develop a protocol for the dose assessment. Entrance skin doses and organ doses were measured by thermoluminescence dosemeters and calculated by Monte Carlo simulations for several X ray examinations. The conversion factor from free air entrance absorbed dose to entrance skin dose was derived. A formula for the computation of entrance skin doses from inputs of kV p , mA.s, source to skin distance, aluminium filtration, and generator rectifying was constructed. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom. All data will be passed to the Atomic Energy Council for developing a programme of national survey and regulatory controls for diagnostic X ray examinations. (author)

  12. X-ray and γ-radiation personnel monitoring by means of ionization chambers

    International Nuclear Information System (INIS)

    Gavrilovskij, L.P.; Nikitin, V.I.

    1981-01-01

    Several sets of condensator ionization chambers for measuring a dose of short-wave X-ray and gamma radiations within the limits of 0.005-50 R is described in short. In particular the following sets for personnel monitoring are described: the KID-2 set intended for determining an exposure dose of roentgen and gamma radiations of 150 keV - 2 MeV energy within the limits of 0.005-1R; the DK-02 set providing the measurement of personnel exposure doses of X-ray and gamma radiations within the limits of 0.02-200 mR in the energy range of 100 keV-2 MeV; the DP-22 V, DP-24 sets providing the measurement of an exposure dose of X-ray and gamma radiations within the limits of 1-50 R at a power of 0.5-200 R/h in the energy range of 0.1-2 MeV. An order of work with the sets is described [ru

  13. Absorbed dose rate meter for β-ray

    International Nuclear Information System (INIS)

    Bingo, K.

    1977-01-01

    The absorbed dose of β-ray depends on the energy of β-rays and the epidermal thickness of tissue in interest. In order to measure the absorbed dose rate at the interested tissue directly, the ratio of counting rate to absorbed dose should be constant independent of β-ray energy. In this purpose, a thin plastic scintillator was used as a detector with a single channel analyzer. The pulse height distribution, obtained using the scintillator whose thickness is less than the range of β-rays, shows a peak at a particular pulse height depending on the thickness of scintillator used. This means an increase of the number of pulses at lower pulse height. The lower level of discrimination and window width of the single channel analyzer are chosen according to the epidermal thickness of the tissue. In the experiment, scintillators of 0.5, 1, 2, 3, 5 and 10 mm thick were tested. It was found that desirable pulse height distribution, to obtain a constant dose sensitivity, could be obtained using the 2 mm thick scintillator. The sensitivity of the absorbed dose rate meter is constant within +-15% for β-ray with maximum energy from 0.4 to 3.5 MeV, when the absorbed dose rate for skin (epidermal thickness 7mg/cm 2 ) is measured. In order to measure the dose rate for a hand (epithermal thickness 40mg/cm 2 ) the lower level of discrimination is changed to be higher and at the same time the window width is also changed. Combining these techniques, one can get an absorbed dose rate meter for the tissue dose of various thickness, which has the constant dose sensitivity within +-15% for β-rays with maximum energy from 0.4 to 3.5 MeV

  14. Dose monitoring in nuclear emergency

    International Nuclear Information System (INIS)

    Nan Hongjie; Yang Zhongping; Lei Xin

    2012-01-01

    In order to protect people from irradiation sickness and rebuild the radiation filed in nuclear emergency, personal and environmental dose need to be monitored. The application of TLD in dose monitoring is discussed in this paper. (authors)

  15. Dose and dose rate monitor

    International Nuclear Information System (INIS)

    Novakova, O.; Ryba, J.; Slezak, V.; Svobodova, B.; Viererbl, L.

    1984-10-01

    The methods are discussea of measuring dose rate or dose using a scintillation counte. A plastic scintillator based on polystyrene with PBD and POPOP activators and coated with ZnS(Ag) was chosen for the projected monitor. The scintillators were cylindrical and spherical in shape and of different sizes; black polypropylene tubes were chosen as the best case for the probs. For the counter with different plastic scintillators, the statistical error 2σ for natural background was determined. For determining the suitable thickness of the ZnS(Ag) layer the energy dependence of the counter was measured. Radioisotopes 137 Cs, 241 Am and 109 Cd were chosen as radiation sources. The best suited ZnS(Ag) thickness was found to be 0.5 μm. Experiments were carried out to determine the directional dependence of the detector response and the signal to noise ratio. The temperature dependence of the detector response and its compensation were studied, as were the time stability and fatigue manifestations of the photomultiplier. The design of a laboratory prototype of a dose rate and dose monitor is described. Block diagrams are given of the various functional parts of the instrument. The designed instrument is easiiy portable, battery powered, measures dose rates from natural background in the range of five orders, i.e., 10 -2 to 10 3 nGy/s, and allows to determine a dose of up to 10 mGy. Accouracy of measurement in the energy range of 50 keV to 1 MeV is better than +-20%. (E.S.)

  16. Thermoluminescent dosimeters for low dose X-ray measurements

    International Nuclear Information System (INIS)

    Del Sol Fernández, S.; García-Salcedo, R.; Sánchez-Guzmán, D.; Ramírez-Rodríguez, G.; Gaona, E.; León-Alfaro, M.A. de; Rivera-Montalvo, T.

    2016-01-01

    The response of TLD-100, CaSO_4:Dy and LiF:Mg,Cu,P for a range of X-ray low dose was measured. For calibration, the TLDs were arranged at the center of the X-ray field. The dose output of the X-ray machine was determined using an ACCU-Gold. All dosimeters were exposed at the available air kerma values of 14.69 mGy within a field 10×10 cm"2 at 80 cm of SSD. Results of LiF:Mg,Cu,P X-ray irradiated showed 4.8 times higher sensitivity than TLD-100. Meanwhile, TL response of CaSO_4:Dy exposed at the same dose was 5.6 time higher than TLD-100. Experimental results show for low dose X-ray measurements a better linearity for LiF:Mg,Cu,P compared with that of TLD-100. CaSO_4:Dy showed a linearity from 0.1 to 60 mGy - Highlights: • Low dose X-ray doses for personal dosimetry were measured. • Radiation dose (µGy ) for environmental dosimetry were determined. • Scattering radiation dose were measured by TLDs. • Linearity of pair TLD system was successful in the range of microgray. • Pair TLDs composed by CaSO_4:Dy and by LiF:Mg,Cu,P. is suggested for clinical dosimetry.

  17. Ambient and personal dose assessment of a container inspection site using a mobile X-ray system

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, F.Y., E-mail: fyhsu@mx.nthu.edu.tw [Nuclear Science and Technology Development Center, National Tsing Hua University, 101, Sec. 2, Kuangfu Rd., 300 Hsinchu, Taiwan (China); Lee, W.F., E-mail: 005679@webmail.customs.gov.tw [Taichung Customs Office, Ministry of Finance, 2, Sec. 3, Chung-Chie Rd., Sha Lu, 435 Taichung, Taiwan (China); Tung, C.J., E-mail: cjtung@mail.cgu.edu.tw [Department of Medical Imaging and Radiological Sciences, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, 333 Tao-Yuan, Taiwan (China); Lee, J.S., E-mail: jslee@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 155 Li-Nong St., Sec. 2, Peitou, 112 Taipei City, Taiwan (China); Wu, T.H., E-mail: tung@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 155 Li-Nong St., Sec. 2, Peitou, 112 Taipei City, Taiwan (China); Hsu, S.M., E-mail: smhsu@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, 91 Hsueh-Shih Rd., 404 Taichung, Taiwan (China); Su, H.T., E-mail: edwardsu1027@hotmail.com [School of Medical Imaging and Radiological Science, Chung Shan Medical University, 110, Sec. 1, Jianguo N. Rd., 402 Taichung, Taiwan (China); Chen, T.R., E-mail: trchen@csmu.edu.tw [School of Medical Imaging and Radiological Science, Chung Shan Medical University, 110, Sec. 1, Jianguo N. Rd., 402 Taichung, Taiwan (China); Department of Medical Image, Chung Shan Medical University Hospital, 402 Taichung, Taiwan (China)

    2012-03-15

    Ambient monitor and phantom studies of absorbed and effective doses by TLDs were carried out in a non-intrusive inspection station for containers, Terminal I, of Taichung harbor, Taiwan. The doses from the X-ray scan in the control room and driver waiting room, located outside of the radiation control area, were quite small and could not be distinguished from the natural background radiation. The doses in the driver cab and the inspector cab of the X-ray scan car were also within background radiation levels. The protection wall, a 40-cm thick concrete barrier, can effectively attenuate the intensity of the primary X-ray scan. The possible effective dose of a person in the container or trailer is about 3.15{+-}0.23 {mu}Sv/scan and 2.31{+-}0.38 {mu}Sv/scan. This dose is below the annual background dose. If someone was to be scanned by the X-ray, the effective dose would be at an acceptable level. - Highlights: Black-Right-Pointing-Pointer We used TLDs to evaluate the dose in the environment and in the Rando phantom. Black-Right-Pointing-Pointer The absorbed dose in the container Terminal showed a natural background level. Black-Right-Pointing-Pointer The protection wall effectively lowers the X-ray intensity. Black-Right-Pointing-Pointer The effective dose of a person in the container or trailer is about 3 {mu}Sv/scan.

  18. 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.

  19. Radiation dose monitoring in the clinical routine

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika [UK Essen (Germany). Radiology

    2017-04-15

    Here we describe the first clinical experiences regarding the use of an automated radiation dose management software to monitor the radiation dose of patients during routine examinations. Many software solutions for monitoring radiation dose have emerged in the last decade. The continuous progress in radiological techniques, new scan features, scanner generations and protocols are the primary challenge for radiation dose monitoring software systems. To simulate valid dose calculations, radiation dose monitoring systems have to follow current trends and stay constantly up-to-date. The dose management software is connected to all devices at our institute and conducts automatic data acquisition and radiation dose calculation. The system incorporates 18 virtual phantoms based on the Cristy phantom family, estimating doses in newborns to adults. Dose calculation relies on a Monte Carlo simulation engine. Our first practical experiences demonstrate that the software is capable of dose estimation in the clinical routine. Its implementation and use have some limitations that can be overcome. The software is promising and allows assessment of radiation doses, like organ and effective doses according to ICRP 60 and ICRP 103, patient radiation dose history and cumulative radiation doses. Furthermore, we are able to determine local diagnostic reference doses. The radiation dose monitoring software systems can facilitate networking between hospitals and radiological departments, thus refining radiation doses and implementing reference doses at substantially lower levels.

  20. Monitoring the eye lens: which dose quantity is adequate?

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G

    2010-01-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity H p (0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity H p (3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of H p (0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of H p (3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of H p (0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.

  1. Dose levels in conventional X-rays

    International Nuclear Information System (INIS)

    Guerra M, J. A.; Gonzalez G, J. A.; Pinedo S, A.; Salas L, M. A.; Vega C, H. R.; Rivera M, T.; Azorin N, J.

    2009-10-01

    There were a series of measures in the General Hospital of Fresnillo in the X-ray Department in the areas of X-1 and X-2-ray rooms and in the neonatal intensive care unit 2, was determined the dose surface entry in eyes, thyroid and gonads for patients undergoing to X-ray study of chest Tele by thermoluminescent dosimetry. Five dosemeters were used in each one of the scans; so find the following dose ranges 20 + - 23 mGy to 350 + - 41 mGy. With the results obtained we can conclude that the procedures used and the equipment calibration is adequate. (Author)

  2. Evaluation of effective dose equivalent from environmental gamma rays

    International Nuclear Information System (INIS)

    Saito, K.; Tsutsumi, M.; Moriuchi, S.; Petoussi, N.; Zankl, M.; Veit, R.; Jacob, P.; Drexler, G.

    1991-01-01

    Organ doses and effective dose equivalents for environmental gamma rays were calculated using human phantoms and Monte Carlo methods accounting rigorously the environmental gamma ray fields. It was suggested that body weight is the dominant factor to determine organ doses. The weight function expressing organ doses was introduced. Using this function, the variation in organ doses due to several physical factors were investigated. A detector having gamma-ray response similar to that of human bodies has been developed using a NaI(Tl) scintillator. (author)

  3. Monitoring Effective Doses Received By Air Crews With A Space Weather Application

    Science.gov (United States)

    Lantos, P.

    To fulfil new requirements of the European Community concerning monitoring of effective doses received by air crews, the French Aviation Authority has developed an operational system called Sievert. The SIEVERT system is analysed as an exam- ple of Space Weather application. One of its characteristics is to calculate the dose received on-board each flight on the basis of the specific and detailled flight given by companies. Operational models will be used. As input to the models, the system needs monitoring of galactic cosmic rays and of solar flare particles. The French neu- tron monitors located in Kerguelen Islands (South Indian Ocean) and Terre Adélie (Antarctica) will be used for this purpose. Particular attention will be devoted to evo- lution of the system in conjunction with new measurements available in the frame of a permanent validation process.

  4. On-Line High Dose-Rate Gamma Ray Irradiation Test of the CCD/CMOS Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In this paper, test results of gamma ray irradiation to CCD/CMOS cameras are described. From the CAMS (containment atmospheric monitoring system) data of Fukushima Dai-ichi nuclear power plant station, we found out that the gamma ray dose-rate when the hydrogen explosion occurred in nuclear reactors 1{approx}3 is about 160 Gy/h. If assumed that the emergency response robot for the management of severe accident of the nuclear power plant has been sent into the reactor area to grasp the inside situation of reactor building and to take precautionary measures against releasing radioactive materials, the CCD/CMOS cameras, which are loaded with the robot, serve as eye of the emergency response robot. In the case of the Japanese Quince robot system, which was sent to carry out investigating the unit 2 reactor building refueling floor situation, 7 CCD/CMOS cameras are used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. In the preceding assumptions, a major problem which arises when dealing with CCD/CMOS cameras in the severe accident situations of the nuclear power plant is the presence of high dose-rate gamma irradiation fields. In the case of the DBA (design basis accident) situations of the nuclear power plant, in order to use a CCD/CMOS camera as an ad-hoc monitoring unit in the vicinity of high radioactivity structures and components of the nuclear reactor area, a robust survivability of this camera in such intense gamma-radiation fields therefore should be verified. The CCD/CMOS cameras of various types were gamma irradiated at a

  5. Measurement and monitoring of entrance exposure dose rate in X-ray image intensifier television with dose rate control

    Energy Technology Data Exchange (ETDEWEB)

    Klein, J [Bezirkskrankenhaus Brandenburg (German Democratic Republic)

    1981-03-01

    For X-ray image intensifier television operation very low entrance dose rates (about 5.2 nA/kg) are stated and demanded, respectively. These required values are often manifold exceeded in practice so that a check seems to be necessary. It is shown and proved how these measurements can be performed with simple, generally available means of measurement in the radiological practice. For ZnCdS-image intensifiers should be considered that about 13 nA/kg for the large entrance size are not to be exceeded; for the CsI type lower values (factor 1.5) are practicable because of the twofold quantum absorption efficiency. Furthermore, some tests for a semiquantitative function check of the automatic dose rate control are proposed.

  6. TU-D-209-06: Head and Neck Tissue Dose From X-Ray Scatter to Physicians Performing Cardiovascular Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Fetterly, K; Schueler, B; Grams, M [Mayo Clinic, Rochester, MN (United States); Sturchio, G [Mayo Clinic, Jacksonville, FL (United States)

    2016-06-15

    Purpose: The purpose of this work was to characterize the spatial distribution of scatter radiation to the head and neck of a physician performing an x-ray interventional procedure and assess brain, eye lens, and carotid artery dose. Methods: Radiographic x-ray beams were tuned to match the peak energy (56 to 106 keV) and HVL (3.5 to 6.5 mm Al) of x-ray scatter originating from a patient during a fluoroscopic procedure. The radiographic beam was directed upon a Rando phantom from an inferior-left location to mimic a typical patient-operator geometric relationship. A lead-equivalent protective garment was secured to the phantom. Direct exposure Gafchromic film (XRQA2) was placed between the transverse plane layers of the head and neck region of the phantom and exposed with 4 scatter-equivalent radiographic beams. A 3×3 cm{sup 2} film placed at the left collar of the phantom was used to monitor incident dose in the position of a radiation monitoring badge. The films were converted to 2D dose distribution maps using FilmQA Pro software and an Epson 11000-XL scanner. The 2D dose distributions maps were normalized by the left collar dose and the percent of left collar dose (%LCD) was calculated for select tissues. Results: The dose maps had high dynamic range (10{sub 4}) and spatial detail. Considering all transverse planes and 4 scatter beam qualities, the median %LCD values were: whole brain 8.5%, left brain 13%, right brain 5.4%, left eye lens 67%, right eye lens 25%, left carotid artery 72%, and right carotid artery 28%. Conclusion: Scatter radiation dose to an operator can be simulated using a tuned radiographic beam and used to expose a phantom and Gafchromic film, thereby creating detailed 2D dose distribution maps. This work facilitates individualized estimation of dose to select head and neck tissues based on an operator’s radiation monitoring badge value.

  7. Cellular response to low Gamma-ray doses

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares A, E; Vega C, H R; Leon, L.C. de . [Unidades Academicas de Estudios Nucleares, Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico); Rebolledo D, O; Radillo J, F [Facultad de Ciencias Biologicas y Agropecuarias de la Universidad de Colima, Colima (Mexico)

    2002-07-01

    Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

  8. Cellular response to low Gamma-ray doses

    International Nuclear Information System (INIS)

    Manzanares A, E.; Vega C, H.R.; Leon, L.C. de; Rebolledo D, O.; Radillo J, F.

    2002-01-01

    Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

  9. In situ measurements of dose rates from terrestrial gamma rays

    International Nuclear Information System (INIS)

    Horng, M.C.; Jiang, S.H.

    2002-01-01

    A portable, high purity germanium (HPGe) detector was employed for the performance of in situ measurements of radionuclide activity concentrations in the ground in Taiwan, at altitudes ranging from sea level to 3900 m. The absolute peak efficiency of the HPGe detector for a gamma-ray source uniformly distributed in the semi-infinite ground was determined using a semi-empirical method. The gamma-ray dose rates from terrestrial radionuclides were calculated from the measured activity levels using recently published dose rate conversion factors. The absorbed dose rate in air due to cosmic rays was derived by subtracting the terrestrial gamma-ray dose rate from the overall absorbed dose rate in air measured using a high-pressure ionization chamber. The cosmic-ray dose rate calculated as a function of altitude, was found to be in good agreement with the data reported by UNSCEAR. (orig.)

  10. Assessment of organ equivalent doses and effective doses from diagnostic X-ray examinations

    International Nuclear Information System (INIS)

    Park, Sang Hyun

    2003-02-01

    The MIRD-type adult male, female and age 10 phantoms were constructed to evaluate organ equivalent dose and effective dose of patient due to typical diagnostic X-ray examination. These phantoms were constructed with external and internal dimensions of Korean. The X-ray energy spectra were generated with SPEC78. MCNP4B ,the general-purposed Monte Carlo code, was used. Information of chest PA , chest LAT, and abdomen AP diagnostic X-ray procedures was collected on the protocol of domestic hospitals. The results showed that patients pick up approximate 0.02 to 0.18 mSv of effective dose from a single chest PA examination, and 0.01 to 0.19 mSv from a chest LAT examination depending on the ages. From an abdomen AP examination, patients pick up 0.17 to 1.40 mSv of effective dose. Exposure time, organ depth from the entrance surface and X-ray beam field coverage considerably affect the resulting doses. Deviation among medical institutions is somewhat high, and this indicated that medical institutions should interchange their information and the need of education for medical staff. The methodology and the established system can be applied, with some expansion, to dose assessment for other medical procedures accompanying radiation exposure of patients like nuclear medicine or therapeutic radiology

  11. Organ or tissue doses, effective dose and collective effective dose from X-ray diagnosis, in Japan

    International Nuclear Information System (INIS)

    Murayama, Takashi; Nishizawa, Kanae; Noda, Yutaka; Kumamoto, Yoshikazu; Iwai, Kazuo.

    1996-01-01

    Effective doses and collective effective doses from X-ray diagnostic examinations were calculated on the basis of the frequency of examinations estimated by a nationwide survey and the organ or tissue doses experimentally determined. The average organ or tissue doses were determined with thermoluminescence dosimeters put at various sites of organs or tissues in an adult and a child phantom. Effective doses (effective dose equivalents) were calculated as the sum of the weighted equivalent doses in all the organs or tissues of the body. As the examples of results, the effective doses per radiographic examination were approximately 7 mGy for male, and 9 mGy for female angiocardiography, and about 3 mGy for barium meal. Annual collective effective dose from X-ray diagnostic examinations in 1986 were about 104 x 10 3 person Sv from radiography and 118 x 10 3 person Sv from fluoroscopy, with the total of 222 x 10 3 person Sv. (author)

  12. Analysis of surface absorbed dose in X-ray grating interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhili, E-mail: wangnsrl@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Wu, Zhao; Gao, Kun; Wang, Dajiang; Chen, Heng; Wang, Shenghao [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Wu, Ziyu, E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-10-15

    Highlights: • Theoretical framework for dose estimation in X-ray grating interferometry. • Potential dose reduction of X-ray grating interferometry compared to conventional radiography. • Guidelines for optimization of X-ray grating interferometry for dose-sensitive applications. • Measure to compare various existing X-ray phase contrast imaging techniques. - Abstract: X-ray phase contrast imaging using grating interferometry has shown increased contrast over conventional absorption imaging, and therefore the great potential of dose reduction. The extent of the dose reduction depends on the geometry of grating interferometry, the photon energy, the properties of the sample under investigation and the utilized detector. These factors also determine the capability of grating interferometry to distinguish between different tissues with a specified statistical certainty in a single raw image. In this contribution, the required photon number for imaging and the resulting surface absorbed dose are determined in X-ray grating interferometry, using a two-component imaging object model. The presented results confirm that compared to conventional radiography, phase contrast imaging using grating interferometry indeed has the potential of dose reduction. And the extent of dose reduction is strongly dependent on the imaging conditions. Those results provide a theoretical framework for dose estimation under given imaging conditions before experimental trials, and general guidelines for optimization of grating interferometry for those dose-sensitive applications.

  13. Analysis of surface absorbed dose in X-ray grating interferometry

    International Nuclear Information System (INIS)

    Wang, Zhili; Wu, Zhao; Gao, Kun; Wang, Dajiang; Chen, Heng; Wang, Shenghao; Wu, Ziyu

    2014-01-01

    Highlights: • Theoretical framework for dose estimation in X-ray grating interferometry. • Potential dose reduction of X-ray grating interferometry compared to conventional radiography. • Guidelines for optimization of X-ray grating interferometry for dose-sensitive applications. • Measure to compare various existing X-ray phase contrast imaging techniques. - Abstract: X-ray phase contrast imaging using grating interferometry has shown increased contrast over conventional absorption imaging, and therefore the great potential of dose reduction. The extent of the dose reduction depends on the geometry of grating interferometry, the photon energy, the properties of the sample under investigation and the utilized detector. These factors also determine the capability of grating interferometry to distinguish between different tissues with a specified statistical certainty in a single raw image. In this contribution, the required photon number for imaging and the resulting surface absorbed dose are determined in X-ray grating interferometry, using a two-component imaging object model. The presented results confirm that compared to conventional radiography, phase contrast imaging using grating interferometry indeed has the potential of dose reduction. And the extent of dose reduction is strongly dependent on the imaging conditions. Those results provide a theoretical framework for dose estimation under given imaging conditions before experimental trials, and general guidelines for optimization of grating interferometry for those dose-sensitive applications

  14. A Performance Evaluation of a Notebook PC under a High Dose-Rate Gamma Ray Irradiation Test

    Directory of Open Access Journals (Sweden)

    Jai Wan Cho

    2014-01-01

    Full Text Available We describe the performance of a notebook PC under a high dose-rate gamma ray irradiation test. A notebook PC, which is small and light weight, is generally used as the control unit of a robot system and loaded onto the robot body. Using TEPCO’s CAMS (containment atmospheric monitoring system data, the gamma ray dose rate before and after a hydrogen explosion in reactor units 1–3 of the Fukushima nuclear power plant was more than 150 Gy/h. To use a notebook PC as the control unit of a robot system entering a reactor building to mitigate the severe accident situation of a nuclear power plant, the performance of the notebook PC under such intense gamma-irradiation fields should be evaluated. Under a similar dose-rate (150 Gy/h gamma ray environment, the performances of different notebook PCs were evaluated. In addition, a simple method for a performance evaluation of a notebook PC under a high dose-rate gamma ray irradiation test is proposed. Three notebook PCs were tested to verify the method proposed in this paper.

  15. High dose gamma-ray standard

    International Nuclear Information System (INIS)

    Macrin, R.; Moraru, R.

    1999-01-01

    The high gamma-ray doses produced in a gamma irradiator are used, mainly, for radiation processing, i.e. sterilization of medical products, processing of food, modifications of polymers, irradiation of electronic devices, a.s.o. The used absorbed doses depend on the application and cover the range 10 Gy to 100 MGy. The regulations in our country require that the response of the dosimetry systems, used for the irradiation of food and medical products, be calibrated and traceable to the national standards. In order to be sure that the products receive the desired absorbed dose, appropriate dosimetric measurements must be performed, including the calibration of the dosemeters and their traceability to the national standards. The high dose gamma-ray measurements are predominantly based on the use of reference radiochemical dosemeters. Among them the ferrous sulfate can be used as reference dosemeter for low doses (up to 400 Gy) but due to its characteristics it deserves to be considered a standard dosemeter and to be used for transferring the conventional absorbed dose to other chemical dosemeters used for absorbed doses up to 100 MGy. The study of the ferrous sulfate dosemeter consisted in preparing many batches of solution by different operators in quality assurance conditions and in determining for all batches the linearity, the relative intrinsic error, the repeatability and the reproducibility. The principal results are the following: the linear regression coefficient: 0.999, the relative intrinsic error: max.6 %, the repeatability (for P* = 95 %): max.3 %, the reproducibility (P* = 95%): max.5 %. (authors)

  16. Routine monitoring of eye dose; and reply

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, K; Jeans, S P; Faulkner, K; Bardsley, R A; Love, H G

    1985-12-01

    This letter briefly reports the assessment at Papworth Hospital of the feasibility of monitoring eye doses of staff using a film badge worn on the shoulder in addition to the badge worn under the lead apron. For three consecutive months hand and eye (forehead) dose were monitored using TLDs, while shoulder and body dose, recorded under the lead apron, were measured with film badges. For the four doctors monitored, (two radiologists and two cardiologists) the shoulder badge somewhat overestimated the eye dose. In the case of nurses, the dose recorded by the shoulder badge was of a similar order to the TLD-recorded eye dose. The reply from the Christie Hospital at Manchester comments on the use of the shoulder badge and contends that the use of forehead dosemeters to measure eye dose is to be preferred whenever possible.

  17. Validation of dose-response calibration curve for X-Ray field of CRCN-NE/CNEN: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Laís Melo; Mendonç, Julyanne Conceição de Goes; Andrade, Aida Mayra Guedes de; Hwang, Suy F.; Mendes, Mariana Esposito; Lima, Fabiana F., E-mail: falima@cnen.gov.br, E-mail: mendes_sb@hotmail.com [Centro Regional de Ciências Nucleares, (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Melo, Ana Maria M.A., E-mail: july_cgm@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Vitória de Santo Antão, PE (Brazil). Centro Acadêmico de Vitória

    2017-07-01

    It is very important in accident investigations that accurate estimating of absorbed dose takes place, so that it contributes to medical decisions and overall assessment of long-term health consequences. Analysis of chromosome aberrations is the most developed method for biological monitoring, and frequencies of dicentric chromosomes are related to absorbed dose of human peripheral blood lymphocytes using calibration curves. International Atomic Energy Agency (IAEA) recommends that each biodosimetry laboratory sets its own calibration curves, given that there are intrinsic differences in protocols and dose interpretations when using calibration curves produced in other laboratories, which could add further uncertainties to dose estimations. The Laboratory for Biological Dosimetry CRCN-NE recently completed dose-response calibration curves for X ray field. Curves of chromosomes dicentrics and dicentrics plus rings were made using Dose Estimate. This study aimed to validate the calibration curves dose-response for X ray with three irradiated samples. Blood was obtained by venipuncture from healthy volunteer and three samples were irradiated by x-rays of 250 kVp with different absorbed doses (0,5Gy, 1Gy and 2Gy). The irradiation was performed at the CRCN-NE/CNEN Metrology Service with PANTAK X-ray equipment, model HF 320. The frequency of dicentric and centric rings chromosomes were determined in 500 metaphases per sample after cultivation of lymphocytes, and staining with Giemsa 5%. Results showed that the estimated absorbed doses are included in the confidence interval of 95% of real absorbed dose. These Dose-response calibration curves (dicentrics and dicentrics plus rings) seems valid, therefore other tests will be done with different volunteers. (author)

  18. Validation of dose-response calibration curve for X-Ray field of CRCN-NE/CNEN: preliminary results

    International Nuclear Information System (INIS)

    Silva, Laís Melo; Mendonç, Julyanne Conceição de Goes; Andrade, Aida Mayra Guedes de; Hwang, Suy F.; Mendes, Mariana Esposito; Lima, Fabiana F.; Melo, Ana Maria M.A.

    2017-01-01

    It is very important in accident investigations that accurate estimating of absorbed dose takes place, so that it contributes to medical decisions and overall assessment of long-term health consequences. Analysis of chromosome aberrations is the most developed method for biological monitoring, and frequencies of dicentric chromosomes are related to absorbed dose of human peripheral blood lymphocytes using calibration curves. International Atomic Energy Agency (IAEA) recommends that each biodosimetry laboratory sets its own calibration curves, given that there are intrinsic differences in protocols and dose interpretations when using calibration curves produced in other laboratories, which could add further uncertainties to dose estimations. The Laboratory for Biological Dosimetry CRCN-NE recently completed dose-response calibration curves for X ray field. Curves of chromosomes dicentrics and dicentrics plus rings were made using Dose Estimate. This study aimed to validate the calibration curves dose-response for X ray with three irradiated samples. Blood was obtained by venipuncture from healthy volunteer and three samples were irradiated by x-rays of 250 kVp with different absorbed doses (0,5Gy, 1Gy and 2Gy). The irradiation was performed at the CRCN-NE/CNEN Metrology Service with PANTAK X-ray equipment, model HF 320. The frequency of dicentric and centric rings chromosomes were determined in 500 metaphases per sample after cultivation of lymphocytes, and staining with Giemsa 5%. Results showed that the estimated absorbed doses are included in the confidence interval of 95% of real absorbed dose. These Dose-response calibration curves (dicentrics and dicentrics plus rings) seems valid, therefore other tests will be done with different volunteers. (author)

  19. Monitoring and dose recording for the individual

    International Nuclear Information System (INIS)

    1988-01-01

    This document specifies the conditions under which monitoring of individuals is required. For workers identified as Atomic Radiation Workers, determination of dose or exposure must be made. In circumstances where personal monitoring techniques are impractical, doses and exposures may be estimated by non-personal monitoring techniques. For workers not identified as Atomic Radiation Workers, licensees must be able to demonstrate that there is no reasonable potential for accumulating radiation doses or exposures in excess of regulatory limits. (L.L.)

  20. Measurement of the external doses at low and high exposures by Agfa personal monitoring film, FD-III-B badge

    International Nuclear Information System (INIS)

    Mihai, F.; Stochioiu, A.; Bercea, S.; Udup, E.; Tudor, I.

    2008-01-01

    Full text: A growing number of papers report occupational exposure monitoring by different dosemeter devices. Researches into improvement of the personal dosemeter systems are encouraged. Dose measurement and especially skin dose measurement, are therefore increasingly important. Methods and acceptable dosemeter are not clearly defined and differ from a dosimetry laboratory to other depending on their specifically work procedure and type of dosemeter utilized. Taking into account the characteristic of the work place (industry, research, medical application) dosemeter have to cover a large dose range. The dose assessment problems are manly in low doses range (under 0.2 mSv) and higher doses range. For example, typical for radiation oncology and nuclear accident dosimetry the dose ranges are on the order of 2-70 Gy and 0.1-5 Gy. This work presents the performance of the Agfa personal monitoring film, badge FD-III-B type used in the most of the occupational exposure monitoring from Romania. The FD-III-B dosimeter, manufactured in Romania, is used for monitoring personnel working in radioactive environment - the photodosimetric method is the one of the most reliable method presenting the advantage that the film may be considered as master probe over 30 year and may be utilized during litigation. The dosimeter contains metallic filters of Al, Cu, Pb with different thicknesses, a plastic filter and a open window. The badge FD-III-B is a class B dosimeter according to the dose range and an indices 3 dosimeter from energy range of the radiations in conformity with Romanian Standard in force. Film Agfa 'personal monitoring', tacked in this experiment, consists of a low speed film (D2) and a very sensitive film (D10) designed for recording X-ray, gamma and beta radiation over the doses range 0.1 mSv to 1 Sv. The experiments have been effectuated at different background optical density (base fog) of the films and at different sources of radiation: 13 :7Cs, 60 Co and 24 : 1 Am

  1. [Evaluation of an Experimental Production Wireless Dose Monitoring System for Radiation Exposure Management of Medical Staff].

    Science.gov (United States)

    Fujibuchi, Toshioh; Murazaki, Hiroo; Kuramoto, Taku; Umedzu, Yoshiyuki; Ishigaki, Yung

    2015-08-01

    Because of the more advanced and more complex procedures in interventional radiology, longer treatment times have become necessary. Therefore, it is important to determine the exposure doses received by operators and patients. The aim of our study was to evaluate an experimental production wireless dose monitoring system for pulse radiation in diagnostic X-ray. The energy, dose rate, and pulse fluoroscopy dependence were evaluated as the basic characteristics of this system for diagnostic X-ray using a fully digital fluoroscopy system. The error of 1 cm dose equivalent rate was less than 15% from 35.1 keV to 43.2 keV with energy correction using metal filter. It was possible to accurately measure the dose rate dependence of this system, which was highly linear until 100 μSv/h. This system showed a constant response to the pulse fluoroscopy. This system will become useful wireless dosimeter for the individual exposure management by improving the high dose rate and the energy characteristics.

  2. Real-time, ray casting-based scatter dose estimation for c-arm x-ray system.

    Science.gov (United States)

    Alnewaini, Zaid; Langer, Eric; Schaber, Philipp; David, Matthias; Kretz, Dominik; Steil, Volker; Hesser, Jürgen

    2017-03-01

    Dosimetric control of staff exposure during interventional procedures under fluoroscopy is of high relevance. In this paper, a novel ray casting approximation of radiation transport is presented and the potential and limitation vs. a full Monte Carlo transport and dose measurements are discussed. The x-ray source of a Siemens Axiom Artix C-arm is modeled by a virtual source model using single Gaussian-shaped source. A Geant4-based Monte Carlo simulation determines the radiation transport from the source to compute scatter from the patient, the table, the ceiling and the floor. A phase space around these scatterers stores all photon information. Only those photons are traced that hit a surface of phantom that represents medical staff in the treatment room, no indirect scattering is considered; and a complete dose deposition on the surface is calculated. To evaluate the accuracy of the approximation, both experimental measurements using Thermoluminescent dosimeters (TLDs) and a Geant4-based Monte Carlo simulation of dose depositing for different tube angulations of the C-arm from cranial-caudal angle 0° and from LAO (Left Anterior Oblique) 0°-90° are realized. Since the measurements were performed on both sides of the table, using the symmetry of the setup, RAO (Right Anterior Oblique) measurements were not necessary. The Geant4-Monte Carlo simulation agreed within 3% with the measured data, which is within the accuracy of measurement and simulation. The ray casting approximation has been compared to TLD measurements and the achieved percentage difference was -7% for data from tube angulations 45°-90° and -29% from tube angulations 0°-45° on the side of the x-ray source, whereas on the opposite side of the x-ray source, the difference was -83.8% and -75%, respectively. Ray casting approximation for only LAO 90° was compared to a Monte Carlo simulation, where the percentage differences were between 0.5-3% on the side of the x-ray source where the highest dose

  3. Novel X-ray telescopes for wide-field X-ray monitoring

    International Nuclear Information System (INIS)

    Hudec, R.; Inneman, A.; Pina, L.; Sveda, L.

    2005-01-01

    We report on fully innovative very wide-field of view X-ray telescopes with high sensitivity as well as large field of view. The prototypes are very promising, allowing the proposals for space projects with very wide-field Lobster-eye X-ray optics to be considered. The novel telescopes will monitor the sky with unprecedented sensitivity and angular resolution of order of 1 arcmin. They are expected to contribute essentially to study and to understand various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc. The Lobster optics based X-ray All Sky Monitor is capable to detect around 20 GRBs and 8 XRFs yearly and this will surely significantly contribute to the related science

  4. Practical experience of monitoring patient dose

    Energy Technology Data Exchange (ETDEWEB)

    McDonnell, C.; Shrimpton, P. (National Radiological Protection Board, Chilton (United Kingdom)); O' Mahoney, M. (National Radiological Protection Board, Leeds (United Kingdom)); Foster, J. (Nuffield Hospitals, Surbiton (United Kingdom))

    1994-05-01

    NRPB recommends the use of reference dose levels for diagnostic medical exposures as an aid to patient dose reduction, but is this approach effective This article describes the broadly encouraging experiences of one large group of hospitals in carrying out measurements of entrance surface dose on patients undergoing some common types of x-ray examination. (author).

  5. Absorbed and effective dose from periapical radiography by portable intraoral x-ray machine

    International Nuclear Information System (INIS)

    Cho, Jeong Yeon; Han, Won Jeong; Kim, Eun Kyung

    2007-01-01

    The purpose of this study was to measure the absorbed dose and to calculate the effective dose for periapical radiography done by portable intraoral x-ray machines. 14 full mouth, upper posterior and lower posterior periapical radiographs were taken by wall-type 1 and portable type 3 intraoral x-ray machines. Thermoluminescent dosemeters were placed at 23 sites at the layers of the tissue-equivalent ART woman phantom for dosimetry. Average tissue absorbed dose and radiation weighted dose were calculated for each major anatomical site. Effective dose was calculated using 2005 ICRP tissue weighted factors. On 14 full mouth periapical radiographs, the effective dose for wall-type x-ray machine was 30 Sv; for portable x-ray machines were 30 Sv, 22 Sv, 36 Sv. On upper posterior radiograph, the effective dose for wall-type x-ray machine was 4 Sv; for portable x-ray machines doses were 4 Sv, 3 Sv, 5 Sv. On lower posterior radiograph, the effective dose for wall type x-ray machine was 5 Sv; for portable x-ray machines doses were 4 Sv, 4 Sv, 5 Sv. Effective doses for periapical radiographs performed by portable intraoral x-ray machines were similar to doses for periapical radiographs taken by wall type intraoral x-ray machines

  6. Shield device for controlling the dose of x-rays applied in an x-ray machine

    International Nuclear Information System (INIS)

    Charrier, P.

    1983-01-01

    This invention provides an improved shield for use with an x-ray machine. The shield can control the dose of x-rays applied by the machine in different areas without affecting the power of the x-rays. This is achieved with a shield especially designed and positioned to intercept with x-rays for longer or shorter periods in different areas during the taking of the picture, but not for the whole period of time necessary for taking this picture. Each area of the subject being x-rayed is exposed to full power x-rays. However, owing to the shield, the areas that require smaller dose receive these full power x-rays for a shorter portion of the time required to take the picture while the other areas that require larger dose of x-rays, receive the full power x-rays for a longer portion of the full period of time required to take the picture. To ensure this differential exposure, the shield is placed through the path of the x-rays and rotated about an axis which is generally transverse to the direction of travel of the x-rays to cut out some of said x-rays for different portions of the period of time necessary for taking the picture. The shield is preferably shaped to intercept x-rays for a longer period in some areas than in others depending on the required doses. A plurality of differently shaped shields can be provided to suit different picture taking situations

  7. SU-G-IeP3-13: Real-Time Patient and Staff Dose Monitoring in Fluoroscopy Guided Interventions

    International Nuclear Information System (INIS)

    Vergoossen, L; Sailer, A; Paulis, L; Wildberger, J; Jeukens, C

    2016-01-01

    Purpose: Interventional radiology procedures involve the use of X-rays, which can pose a large radiation burden on both patients and staff. Although some reports on radiation dose are available, most studies focus on limited types of procedures and only report patient dose. In our cathlabs a dedicated real-time patient and staff monitoring system was installed in November 2015. The aim of this study was to investigate the patient and staff dose exposure for different types of interventions. Methods: Radiologists involved in fluoroscopy guided interventional radiology procedures wore personal dose meters (PDM, DoseAware, Philips) on their lead-apron that measured the personal dose equivalent Hp(10), a measure for the effective dose (E). Furthermore, reference PDMs were installed in the C-arms of the fluoroscopy system (Allura XPer, Philips). Patient dose-area-product (DAP) and PDM doses were retrieved from the monitoring system (DoseWise, Philips) for each procedure. A total of 399 procedures performed between November 2015 and February 2016 were analyzed with respect to the type of intervention. Interventions were grouped by anatomy and radiologist position. Results: The mean DAP for the different types of interventions ranged from 2.86±2.96 Gycm"2 (percutaneous gastrostomy) to 147±178 Gycm"2 (aortic repair procedures). The radiologist dose (E) ranged from 5.39±7.38 µSv (cerebral interventions) to 84.7±106 µSv (abdominal interventions) and strongly correlated with DAP (R"2=0.83). The E normalized to DAP showed that the relative radiologist dose was higher for interventions in larger body parts (e.g. abdomen) compared to smaller body parts (e.g. head). Conclusion: Using a real-time dose monitoring system we were able to assess the staff and patient dose revealing that the relative staff dose strongly depended on the type of procedure and patient anatomy. This could be explained by the position of the radiologist with respect to the patient and X-ray tube. To

  8. Development of a portable monitor for detecting gamma radiation and X-rays

    International Nuclear Information System (INIS)

    Silva Neto, Paulo J. da; Lira, Carlos A.B. de O.; Oliveira, Arno H. de

    2011-01-01

    There are several ways to prevent individuals from receiving excessive or unnecessary doses of radiation, and area monitoring contributes to the radiation protection in the assessment whether these means are really efficient. The area monitoring is used to give an indication of radiation levels in certain locations. Using this method, one can estimate the dose received by staff occupying a particular area for a certain period of time. Hence, the purpose of this work was the construction of a portable monitor, consisting of an ionization chamber, with a volume of approximately 517 cc and built from tissue-equivalent material, and of its associated electronics. Radiation measurements of gamma and X-rays beams were then possible. The results showed a linear response of the monitor for different dose rates. The stability test of the response also showed a good reproducibility within ± 1%. A low energy dependence for energies between 16 - 200keV was observed, and complied well with the IEC 60846 standard. However, for the energy range 200 - 1250keV, the discrepancies to the IEC standard are considerable, so that the interposition of filters is necessary and may improve the energy response curve to within acceptable limits. (author)

  9. Dose enhancement effects of X ray radiation in bipolar transistors

    International Nuclear Information System (INIS)

    Chen Panxun

    1997-01-01

    The author has presented behaviour degradation and dose enhancement effects of bipolar transistors in X ray irradiation environment. The relative dose enhancement factors of X ray radiation were measured in bipolar transistors by the experiment methods. The mechanism of bipolar device dose enhancement was investigated

  10. Cellular Stress to Low Gamma-ray Dose

    International Nuclear Information System (INIS)

    Manzanares-Acuna, E.; Vega-Carrillo, H. R.; Letechipia de Leon, C.; Guzman Enriquez, L. J.; Garcia-Talavera, M.

    2004-01-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp 70 expression in human lymphocytes. the heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. when a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered through overexpression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the lymphocytes were isolated by ficoll-histopaque gradient. Experimental lots were irradiated in a ''137Cs gamma-ray. Hsp70 expression was found since 0.5 cGy, indicating a threshold to very low doses of gamma rays. (Author) 27 refs

  11. Possible radiation dose reduction by using digital X-ray equipment

    International Nuclear Information System (INIS)

    Horvathova, M.; Nikodemova, D.; Prikazska, M.

    2001-01-01

    The radiation load of population all over the world from medical examinations clearly demonstrates the importance of the introduction of the quality assurance and quality control programmes into the activities of radiology departments. The basic aim of quality assurance program is to ensure that the radiation dose is kept as low as reasonably practicable while still providing an adequate image quality. As many other fields, the rapid development of techniques brought change-over from the conventional analogue technique to the digital technique. In this process, the conventional X-ray film is being abandoned and images are being viewed on either laser film or monitor. The main advantages of using digital equipment lay in improved image quality and diagnostic accuracy through digital image processing, reduction in patients exposure, cost reduction by reduction of the film usage, more efficient storage and retrieval of radiographic images through picture archiving. Several studies that have been conducted for comparison of various diagnostic examinations show , that there is potential for dose saving in the digital image intensifier technique. The aim of this study was to compare measured values of dose-area product for colon investigations using different X-ray equipment types, two digital and two analogue. Our material consisted of 169 randomly selected patients, 115 of them were examined with digital equipment and 54 patients with the analogue equipment. The obtained results have confirmed the dose reduction and increase of diagnostic accuracy when using the digital equipment, with the added benefit of a good image quality. (authors)

  12. Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

    International Nuclear Information System (INIS)

    Underbrink, A.G.; Kellerer, A.M.; Mills, R.E.; Sparrow, A.H.; Brookhaven National Lab., Upton, N.Y.

    1976-01-01

    Microdosimetric data indicate that the mean specific energy, xi, produced by individual charged particles from X rays and gamma rays is different for the two radiation qualities by nearly a factor of two. In order to test whether this influences the initial, linear component in the dose-effect relations, a comparison was made between dose-response curves for pink somatic mutations in Tradescantia clone 02 stamen hairs following X and gamma irradiations. Absorbed doses ranged from 2.66 to 300 rad. The results are in agreement with predictions made on the basis of microdosimetric data. At low doses gamma rays are substantially less effective than X rays. The RBE of gamma rays vs. X rays at low doses was approximately 0.6, a value lower than those usually reported in other experimental systems. (orig.) [de

  13. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    International Nuclear Information System (INIS)

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan

    2012-01-01

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED adj ). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED adj between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED adj that differed by up to 44% from effective dose estimates that were not

  14. Trends in x-ray photography and patient exposure dose

    International Nuclear Information System (INIS)

    Orito, Takeo; Sanada, Shigeru; Maekawa, Ryuichi; Koshida, Kichiro; Hiraki, Tatsunosuke

    1980-01-01

    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. (J.P.N.)

  15. Comparative study of radiation dose between digital panoramic X-ray unit and general panoramic X-ray unit

    International Nuclear Information System (INIS)

    Li Qingshan; Duan Tao; Wang Xiaoyun; Zhao Li; Dong Jian; Wei Lei

    2010-01-01

    Objective: To compare the actual dose of patients who receive the same medical practice by either digital panoramic X-ray unit and general panoramic X-ray unit and give evidence for better selection of oral X-ray examination method. Methods: Round sheet lithium fluoride (LiF) thermoluminescent dosimeters (TLD) were used. The experiment was divided into natural background contrast group, general panoramic X-ray children group, general panoramic X-ray adults group, digital panoramic X-ray children group and digital panoramic X-ray adults group. The dosimeter of natural background radiation was placed at the office of the doctor, the dosimeters of general panoramic X-ray children group and general panoramic X-ray adults group were irradiated by different conditions according to the clinical application of panoramic X-ray to children and adults, the dosimeters of digital panoramic X-ray children group and digital panoramic X-ray adults group were irradiated by different conditions according to the clinical application of digital panoramic X-ray to children and adults. The thermoluminescent dosimeter was used to count and calculate the exposure doses in various groups. Results: The dose of children exposed in general panoramic X-ray unit was 1.28 times of that in digital panoramic X-ray unit, there was significant difference (t=6.904, P<0.01). The dose of adults exposed in general panoramic X-ray unit was 1.55 times of that in the digital panoramic X-ray unit, there also was significant difference (t=-11.514. P< 0.01). Conclusion: The digital panoramic X-ray unit can reduce the dose of patients, so the digital panoramic X-ray unit should be used as far as possible. (authors)

  16. The dose received by patients during dental X-ray examination and the technical condition of radiological equipment.

    Science.gov (United States)

    Bekas, Marcin; Pachocki, Krzysztof A

    2013-01-01

    Implementation of X-ray dental examination is associated with the patients exposure to ionizing radation. The size of the exposure depends on the type of medical procedure, the technical condition of the X-ray unit and selected exposure conditions. The aim of this study was to determine the dose received by patients during dental X-ray examination and the assessment of the technical condition of medical equipment, The study included a total number of 79 dental X-ray units located in the region of Mazovia. The test methods for the assessment of the technical condition of dental X-ray units and measurement of radiation dose received by patients were based on the procedures elaborated in the Department of Radiation Hygiene and Radiobiology in the National Institute of Public Health - National Institute of Hygiene (Warszawa, Poland) accredited for the certification of compliance with PN-EN 17025. The research found that 69.6% fully meets the criteria set out in the Polish legislation regarding the safe use of ionizing radiation in medicine, while 30.4% did not meet some of them. A tenfold difference in the size of the dose received by patients during dental X-ray examinations was discovered. For example, during a radiography of the canine teeth of a child, the recorded entrance surface dose (ESD) ranged from 72.8 to 2430 microGy with the average value of 689.1 microGy. Cases where the dose reference level defined in Polish legislation of 5 mGy was exceeded were also found. CONCKUSIONS: It is essential to constantly monitor the situation regarding the technical condition of X-ray units which affects the size of the population's exposure to ionizing radiation as well as raising dentists' awareness about the effects of X-rays on the human body.

  17. Effects of X-rays spectrum on the dose

    International Nuclear Information System (INIS)

    Rodriguez I, J. L.; Hernandez A, P. L.; Vega C, H. R.; Rivera M, T.

    2015-10-01

    The X-ray equipment for diagnosis comes in different sizes and shapes depending on the scan type to perform. The X-ray spectrum is the energy distribution of the beam photons and consists of a continuous spectrum of photons braking and discrete spectrum due to the characteristic photons. The knowledge of the X-rays spectrum is important to understand like they affect the voltage changes (k Vp), current (m A), time (s) and the type of filter in the interaction mechanisms between X-rays and patient's body, the image receptor or other material that gets in the beam. Across the spectrum can be estimated the absorbed dose in any point of the patient, the quality of the image and the scattered radiation (which is related to the dose received by the equipment operator). The Monte Carlo method was used by MCNP5 code to calculate the spectrum of X-rays that occurs when a monoenergetic electron beam of 250 keV interact with targets of Mo, Rh and W. The spectra were calculated with and without filter, and the values of ambient dose equivalent were estimated, as well as the air kerma. (Author)

  18. X-ray area monitor

    International Nuclear Information System (INIS)

    Nintrakit, N.

    1983-01-01

    The X-ray area monitor is a nuclear electronic device that is essential in radiation protection in high radiation laboratories, e.g. in medical diagnosis using X-rays and in industrial X-radiography. Accidentally the level of X-radiator may arise above the safe permissible level and in such a case the alarm system of the area monitor will work and disconnect the ac power supply form the X-ray unit. Principally the device is a radiation counter using G.M.tube as radiation detector with high voltage supply variable form 200 to 2,000 volts. The maximum count rate of the scaler is 1.5 MHz and the total count is displayed on 4 digit LED's. A time base is used to control the counting time, the frequency multiplier, radiation safety limit, comparator and the radiation hazard warning signal. The reliability of the instrument is further enhanced through the addition of the random correction circuit, and it is applicable both in X- and γ -radiation

  19. 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.)

  20. Estimation of inhalation doses from airborne releases using gross monitors

    International Nuclear Information System (INIS)

    Goldstein, N.P.

    1978-01-01

    Monitoring programs at most nuclear facilities involve continuous gross measurements supplemented by periodic isotopic analyses of release samples. The isotopic measurements are required to accurately assess the potential dose from the various effluent streams, but in between these measurements, one depends on the gross monitors to provide approximate indications of the dose. The effluent streams release a variety of nuclides, each with its own dose factor. This means that the relationship between the counting rate in a gross monitor and the potential dose of the effluent being monitored will depend on the isotopic composition of this release. If this composition changes, then the dose indicated by the gross monitor (calibrated for the original group of isotopes) may be significantly in error. The problem of indicating inhalation doses from gross monitoring of airborne releases is considered. In order for this type of monitor to accurately indicate dose, regardless of the isotopic makeup of a release, the analysis shows that its response to each isotope should be proportional to the dose factor of that isotope. These ideas are applied to the monitoring of air particulates using gross beta and gross gamma monitors. The study shows that the former more closely satisfies this condition and as a result, satisfactorily indicates the actual dose from reactor effluents, as determined from detailed isotopic data published in the literature. On the other hand, the gross gamma monitor, with its poorer fit to the condition, provided less than satisfactory accuracy in its dose estimates. In addition, a variety of other mathematical response functions were considered but their dose estimation capabilities were not much better than the straight beta response. The study shows that reasonably accurate dose estimates can be made using properly selected gross monitors, but that significant errors can result with improper ones. (author)

  1. Next generation x-ray all-sky monitor

    International Nuclear Information System (INIS)

    Priedhorsky, W. C.; Peele, A. G.; Nugent, K. A.

    1997-01-01

    We set forth a conceptual design for x-ray all-sky monitor based on lobster-eye wide-field telescopes. This instrument, suitable for a small satellite, would monitor the flux of objects as faint as 2x10 -15 W/m 2 (0.5-2.4 keV) on a daily basis with a signal-to-noise of 5. Sources would be located to 1-2 arc-minutes. Detailed simulations show that crosstalk from the cruciform lobster images would not significantly compromise performance. At this sensitivity limit, we could monitor not just x-ray binaries but fainter classes of x-ray sources. Hundreds of active galactic nuclei, coronal sources, and cataclysmic variables could be tracked on a daily basis. Large numbers of fast transients should be visible, including gamma-ray bursts and the soft x-ray breakout of nearby type II supernovae. Long-term x-ray measurements will advance our understanding of the geometries and perhaps masses of AGN, and coronal energy sources in stars

  2. Tissue doses in X-ray examinations of osteoarticular system

    International Nuclear Information System (INIS)

    Rabkin, I.Kh.; Stavitskij, R.V.; Blinov, N.N.; Vasil'ev, Yu.D.

    1985-01-01

    The X-ray method in diagnosis of the osteoarticular system disease is described. Problems on tissue dose distribution in X-ray examinations of a skeleton, a skull, humeral articulation, cervical, thoracic and lumbar vertebrae, hip joint, hipbones are considered. The values of specific tissue doses in roentgenography of the osteoarticular system are given

  3. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    Energy Technology Data Exchange (ETDEWEB)

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan [Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States) and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2012-11-15

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose

  4. Dose monitoring in radiology departments. Status quo and future perspectives

    International Nuclear Information System (INIS)

    Boos, J.; Bethge, O.T.; Antoch, G.; Kroepil, P.

    2016-01-01

    The number of computed tomography examinations has continuously increased over the last decades and accounts for a major part of the collective radiation dose from medical investigations. For purposes of quality assurance in modern radiology a systematic monitoring and analysis of dose related data from radiological examinations is mandatory. Various ways of collecting dose data are available today, for example the Digital Imaging and Communication in Medicine - Structured Report (DICOM-SR), optical character recognition and DICOM-modality performed procedure steps (MPPS). The DICOM-SR is part of the DICOM-standard and provides the DICOM-Radiation Dose Structured Report, which is an easily applicable and comprehensive solution to collect radiation dose parameters. This standard simplifies the process of data collection and enables comprehensive dose monitoring. Various commercial dose monitoring software devices with varying characteristics are available today. In this article, we discuss legal obligations, various ways to monitor dose data, current dose monitoring software solutions and future perspectives in regard to the EU Council Directive 2013/59/EURATOM.

  5. Gamma ray spectroscopy monitoring method and apparatus

    Science.gov (United States)

    Stagg, William R; Policke, Timothy A

    2017-05-16

    The present invention relates generally to the field of gamma ray spectroscopy monitoring and a system for accomplishing same to monitor one or more aspects of various isotope production processes. In one embodiment, the present invention relates to a monitoring system, and method of utilizing same, for monitoring one or more aspects of an isotope production process where the monitoring system comprises: (A) at least one sample cell; (B) at least one measuring port; (C) at least one adjustable collimator device; (D) at least one shutter; and (E) at least one high resolution gamma ray spectrometer.

  6. Organ doses as a function of body weight for environmental gamma rays

    International Nuclear Information System (INIS)

    Saito, Kimiaki; Petoussi, N.; Zankl, M.; Veit, R.; Jacob, P.; Drexler, G.

    1991-01-01

    The organ doses for γ rays from typical environmental sources were determined with Monte Carlo calculations using anthropomorphic phantoms having different body sizes. It has been suggested that body weight is the predominant factor influencing organ doses for environmental γ rays, regardless of sex and age. A weight function expressing organ doses for environmental γ rays was introduced. This function fitted well with the organ doses calculated using the different phantoms. The function coefficients were determined mathematically with the least squares method. On the assumption that this function was applicable to organ doses for human bodies with diverse characteristics, the variances in organ doses due to race, sex, age and difference in body weight of adults were investigated. The variations of organ doses due to race and sex were not significant. Differences in body weight were found to alter organ doses by a maximum of 10% for γ rays over 100 keV, and 20% for low-energy γ rays. The doses for organs located deep inside a body, such as ovaries, differed between a newborn baby and an adult by a maximum factor of 2 to 3. For γ rays over 100 keV, the variation was within a factor of 2 for all organs. The organ doses for adolescents more than 12 years agreed within 15% with those of the average adult. (author)

  7. Cytogenetics dosimetry: dose-response curve for low doses of X-ray

    International Nuclear Information System (INIS)

    Lara, Virginia E. Noval; Pineda Bolivar, William R.; Riano, Victor M. Pabon; Ureana, Cecilia Crane

    2013-01-01

    The purpose of this study was to conduct a preliminary study for the standardization in the future, the dose-response curve for low doses of X-rays, through the analysis of in vitro cultures of peripheral blood samples of 3 men and 3 women occupationally not exposed to artificial sources of ionizing radiation, age 18-40 years, where possible nonsmokers

  8. Experimental study on x-rays dose enhancement effects for floating gate ROMs

    CERN Document Server

    Guo Hong Xia; Chen Yu Sheng; Han Fu Bin; He Chao Hui; Zhao Hui

    2002-01-01

    Experimental results of x-ray dose enhancement effects are given for floating gate read-only memory (ROMs) irradiated in the Beijing Synchrotron Radiation Facility. The wrong byte numbers vs. total irradiation dose have been tested and the equivalent relation of total dose damage is provided compared the response of devices irradiated with sup 6 sup 0 Co gamma-ray source. The x-ray dose enhancement factors for floating gate ROMs are obtained firstly in China. These results can be an effective evaluation data for x-rays radiation hardening technology

  9. Monitor inspection device

    International Nuclear Information System (INIS)

    Ueshima, Yoshinobu.

    1995-01-01

    The device of the present invention reliably conducts monitoring by radiation monitors in a nuclear power plant thereby contributing to save the number of radiation operators and reduction of radiation exposure. Namely, radiation monitors continuously measure a plurality of γ-ray levels. A branched simultaneously counting circuit receives these signals. The output of the branched simultaneously counting circuit is inputted to a differentiation means. The differentiation means calculates a variation coefficient for each of the radiation monitoring values, namely, equivalent dose rates, and records and monitors change with time of the equivalent dose rates. With such procedures, the results of the monitoring of γ-ray levels can be judged objectively corresponding to the increase of the equivalent dose rates. As a result, the number of radiation operators can be saves and radiation exposure of the radiation operators can be reduced. (I.S.)

  10. Impact of digital imaging on radiation doses to the patient during X-ray examination of the urinary tract.

    Science.gov (United States)

    Sjöholm, B; Geijer, H; Persliden, J

    2005-10-01

    To compare radiation doses given to patients undergoing IVU (intravenous urography) before and after digitalization of our X-ray department. IVU examinations were monitored with dose area product meters before and after the X-ray department changed to digital techniques. The first step was a change from film-screen to storage phosphor plates, while the second step involved changing to a flat panel detector. Forty-two patients were included for the film-screen situation, 69 when using the storage phosphor plates, and 70 using the flat panel detector. A dose reduction from 41.8 Gycm2 to 31.5 Gycm2 was achieved with the first step when the film-screen system was replaced with storage phosphor plates. A further reduction to 12.1 Gycm2 was achieved using the flat panel detector. The introduction of the flat panel detectors made a considerable dose reduction possible.

  11. Dose Matters: FDA's Guidance on Children's X-rays

    Science.gov (United States)

    ... Consumer Updates Dose Matters: FDA's Guidance on Children's X-rays Share Tweet Linkedin Pin it More sharing options ... exposure during medical procedures. The level of ionizing radiation from X-ray imaging is generally very low, but can ...

  12. Studies of the dose distribution for patients undergoing various examinations in x-ray diagnosis and methods optimization

    International Nuclear Information System (INIS)

    Schandorf, Cyril

    2002-01-01

    The analysis of the status of x-ray diagnosis in Ghana revealed that Ghana is in the health care Category III, since there are about 4,2000 people to each physicians-ray departments have no quality management and quality control system in place for monitoring the quality of diagnostic images. Education and training in radiation protection and cost-effective use of x-rays are needed as part of the educational programme for radiologists, radiographers, x-ray technical officers and darkroom attendants. The dose and dose distribution for adult patients undergoing chest PA, lumber spine AP, pelvis/abdomen AP, and Skull AP examinations were determined using thermoluminescence dosemeters and compared with Commission of the European Communities guideline values. Analysis of the data show that 86%, 58% and 50% of the radiographic room delivered doses to patients compared the CEC value for Chest PA, lumber spine AP, pelvis/Abdomen AP and Skull AP respectively. Radiographic departments therefore should review their radiographic procedures to bring their does to optimum levels. Three methods were investigated for use as dose reduction optimization options. With the establishment of administrative procedures for the control of indiscriminate requests and referral criteria for x-ray examinations, patient dose can be averted. It is estimated about 10man.Sv can be averted annually. Authorized exposures can be minimized by standardizing the parameters which have significant influence on patient dose, taking into account screen-film system and film processing. By optimization the techniques factors, entrance surface dose and effective dose can be reduced. For chest PA examination the reduction factors are 4 and 3 respectively. Corresponding values for lumber spine AP, pelvis/abdomen AP and skull AP are 2 and 1.8, 1.4 and 1.4, 2.0 and 1.8 respectively. Three local materials, Ghanaian Anum Serpentine (SGA), Ghanaian Peki-Dzake Serpentine (SGP) and Ghanaian Golokwati Serpentine (SGG

  13. Cosmic Ray Modulation and Radiation Dose of Aircrews During Possible Grand Minimum

    Science.gov (United States)

    Miyake, S.; Kataoka, R.; Sato, T.; Imada, S.; Miyahara, H.; Shiota, D.; Matsumoto, T.; Ueno, H.

    2017-12-01

    The Sun is exhibiting low solar activity levels since the descending phase of the last solar cycle, and it is likely to be continued as well as in the case of the past grand solar minima. The cosmic-ray modulation, which is the variation of the galactic cosmic ray (GCR) spectrum caused by the heliospheric environmental change, is basically anti-correlated with the solar activity. In the recent weak solar cycle, we thus expect that the flux of GCRs is getting higher than that in the previous solar cycles, leading to the increase in the radiation exposure in the space and atmosphere. In order to quantitatively evaluate the possible solar modulation of GCRs and resultant radiation exposure at flight altitude, we have developed the time-dependent and three-dimensional model of the cosmic-ray modulation. Our model can give the flux of GCRs anywhere in the heliosphere by assuming the variation of the solar wind speed, the strength of the heliospheric magnetic field (HMF), and its tilt angle. We solve the gradient-curvature drift motion of GCRs in the HMF, and therefore reproduce the 22-year variation of the cosmic-ray modulation. We also calculate the neutron monitor counting rate and the radiation dose of aircrews at flight altitude, by the air-shower simulation performed by PHITS (Particle and Heavy Ion Transport code System). In our previous study [1], we calculated the radiation dose at a flight altitude during the coming solar cycle by assuming the variation of the solar wind speed and the strength of the HMF expressed by sinusoidal curve, and obtained that an annual radiation dose of aircrews in 5 years around the next solar minimum will be up to 19% higher than that at the last cycle. In this study, we predict the new model of the heliospheric environmental change on the basis of a prediction model for the sunspot number. The quantitative predictions of the cosmic-ray modulation and the radiation dose at a flight altitude during possible Grand Minimum considering

  14. Reduction of doses from diagnostic X-ray procedures

    International Nuclear Information System (INIS)

    Gudden, F.; Kuhn, H.

    1992-01-01

    More recent developments in the field of receiver systems for X-rays have made it possible for doses required in X-ray examinations to be gradually reduced to no more than 5% of the radiation patients were exposed to 30 years ago. Despite this fact, the image quality standards necessary to establish even considerably improved. The author suggests to repeat series of measurements carried out in the distant past to be able to make a population-based assessment of the current risk from the effective equivalence dose in one year. In all likelihood, such a survey would prove the quivalence dose to be much lower than the degree of environmental radiation exposure. (orig./DGD) [de

  15. X-ray and radioiodine dose to thyroid follicular cells

    International Nuclear Information System (INIS)

    Faw, R.E.

    1991-01-01

    Radiation doses to the epithelial cells of thyroid follicles have been calculated for internal exposure by radionuclides of iodine and by secondary radiations created as a result of interactions of externally administered x rays with iodine naturally occurring in the thyroid. Calculations were performed for the thyroids of subjects ranging from the newborn to the adult male. Results for internal radionuclides are reported as the dose rate to follicular-cell nuclei per unit specific activity of the radionuclide in the thyroid as a whole, i.e., as the specific ''S value'' as used in the MIRD method for internal dosimetry. Results for x rays are reported as the response function, i.e., the absorbed dose per unit fluence of primary x rays. Dose rates are subdivided into internal and external components, the former from radiations emitted within the colloid volume of any one follicle, and the latter from radiations emitted throughout the thyroid in follicles surrounding that one follicle. 37 refs., 5 figs., 3 tabs

  16. Continuing education: online monitoring of haemodialysis dose.

    Science.gov (United States)

    Vartia, Aarne

    2018-01-25

    Kt/V urea reflects the efficacy of haemodialysis scaled to patient size (urea distribution volume). The guidelines recommend monthly Kt/V measurements based on blood samples. Modern haemodialysis machines are equipped with accessories monitoring the dose online at every session without extra costs, blood samples and computers. To describe the principles, devices, benefits and shortcomings of online monitoring of haemodialysis dose. A critical literature overview and discussion. UV absorbance methods measure Kt/V, ionic dialysance Kt (product of clearance and treatment time; cleared volume without scaling). Both are easy and useful methods, but comparison is difficult due to problems in scaling of the dialysis dose to the patient's size. The best dose estimation method is the one which predicts the quality of life and survival most accurately. There is some evidence on the predictive value of ionic dialysance Kt, but more documentation is required on the UV method. Online monitoring is a useful tool in everyday quality assurance, but blood samples are still required for more accurate kinetic modelling. After reading this article the reader should be able to: Understand the elements of the Kt/V equation for dialysis dose. Compare and contrast different methods of measurement of dialysis dose. Reflect on the importance of adequate dialysis dose for patient survival and life quality. © 2018 European Dialysis and Transplant Nurses Association/European Renal Care Association.

  17. UHV photoelectron x-ray beam position monitor

    International Nuclear Information System (INIS)

    Johnson, E.D.; Oversluizen, T.

    1989-01-01

    As part of our research program to develop viable beam position monitors for both the X-ray and VUV beamlines at the NSLS, we have constructed vertical photon beam position monitors which are presently mounted in two front-ends in the X-ray ring. These area-type detectors are located before the safety shutters and are, therefore, able to monitor the beam position even during injection. The features of this type of monitor which contribute to its long-term stability, position sensitivity, and immunity to horizontal beam motion have been examined and will be discussed. 6 refs., 4 figs

  18. Design of movable fixed area γ dose rate monitor

    International Nuclear Information System (INIS)

    Li Dongyu; Cheng Wen; Li Jikai; Huang Hong; Shen Qiming; Zhang Qiang; Liu Zhengshan

    2005-10-01

    Movable fixed area γ dose rate monitor has not only the characteristics of fixed area γ dose rate monitor, but that of portable meter as well. Its main function is to monitor the areas where dose rate would change without orderliness to prevent unplanned radiation exposure accidents from happening. The design way of the monitor, the main indicators description, the working principle and the comprising of software and hardware are briefly introduced. The monitor has the characteristics of simple installation, easy maintenance, little power consumption, wide range, notability of visual and audible alarm and so on. Its design and technique have novelty and advancement. (authors)

  19. Edge enhancement algorithm for low-dose X-ray fluoroscopic imaging.

    Science.gov (United States)

    Lee, Min Seok; Park, Chul Hee; Kang, Moon Gi

    2017-12-01

    Low-dose X-ray fluoroscopy has continually evolved to reduce radiation risk to patients during clinical diagnosis and surgery. However, the reduction in dose exposure causes quality degradation of the acquired images. In general, an X-ray device has a time-average pre-processor to remove the generated quantum noise. However, this pre-processor causes blurring and artifacts within the moving edge regions, and noise remains in the image. During high-pass filtering (HPF) to enhance edge detail, this noise in the image is amplified. In this study, a 2D edge enhancement algorithm comprising region adaptive HPF with the transient improvement (TI) method, as well as artifacts and noise reduction (ANR), was developed for degraded X-ray fluoroscopic images. The proposed method was applied in a static scene pre-processed by a low-dose X-ray fluoroscopy device. First, the sharpness of the X-ray image was improved using region adaptive HPF with the TI method, which facilitates sharpening of edge details without overshoot problems. Then, an ANR filter that uses an edge directional kernel was developed to remove the artifacts and noise that can occur during sharpening, while preserving edge details. The quantitative and qualitative results obtained by applying the developed method to low-dose X-ray fluoroscopic images and visually and numerically comparing the final images with images improved using conventional edge enhancement techniques indicate that the proposed method outperforms existing edge enhancement methods in terms of objective criteria and subjective visual perception of the actual X-ray fluoroscopic image. The developed edge enhancement algorithm performed well when applied to actual low-dose X-ray fluoroscopic images, not only by improving the sharpness, but also by removing artifacts and noise, including overshoot. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Personnel external dose monitoring system

    International Nuclear Information System (INIS)

    Zhao Hengyuan

    1989-01-01

    The status and trend of personnel external dose monitoring system are introduced briefly. Their characteristics, functions and TLD bedges of some commercially available automatic TLD system, including UD-710A (Matsushita, Japan), Harshaw-2271, 2276 (Harshaw, USA), Harshaw-8000 (Harshaw/Filtrol), Studsvik-1313 (Sweden) and Pitman-800 (UK) were depicted in detail. Finally, personnel dose management and record keeping system were presented and two examples were given

  1. X-ray astronomy 2000: Wide field X-ray monitoring with lobster-eye telescopes

    International Nuclear Information System (INIS)

    Inneman, A.; Hudec, R.; Pina, L.; Gorenstein, P.

    2001-01-01

    The recently available first prototypes of innovative very wide field X-ray telescopes of Lobster-Eye type confirm the feasibility to develop such flight instruments in a near future. These devices are expected to allow very wide field (more than 1000 square degrees) monitoring of the sky in X-rays (up to 10 keV and perhaps even more) with faint limits. We will discuss the recent status of the development of very wide field X-ray telescopes as well as related scientific questions including expected major contributions such as monitoring and study of X-ray afterglows of Gamma Ray Bursts

  2. Robust ray-tracing algorithms for interactive dose rate evaluation

    International Nuclear Information System (INIS)

    Perrotte, L.

    2011-01-01

    More than ever, it is essential today to develop simulation tools to rapidly evaluate the dose rate received by operators working on nuclear sites. In order to easily study numerous different scenarios of intervention, computation times of available softwares have to be all lowered. This mainly implies to accelerate the geometrical computations needed for the dose rate evaluation. These computations consist in finding and sorting the whole list of intersections between a big 3D scene and multiple groups of 'radiative' rays meeting at the point where the dose has to be measured. In order to perform all these computations in less than a second, we first propose a GPU algorithm that enables the efficient management of one big group of coherent rays. Then we present a modification of this algorithm that guarantees the robustness of the ray-triangle intersection tests through the elimination of the precision issues due to floating-point arithmetic. This modification does not require the definition of scene-dependent coefficients ('epsilon' style) and only implies a small loss of performance (less than 10%). Finally we propose an efficient strategy to handle multiple ray groups (corresponding to multiple radiative objects) which use the previous results.Thanks to these improvements, we are able to perform an interactive and robust dose rate evaluation on big 3D scenes: all of the intersections (more than 13 million) between 700 000 triangles and 12 groups of 100 000 rays each are found, sorted along each ray and transferred to the CPU in 470 milliseconds. (author) [fr

  3. Generalized concept for the estimation of body dose for radiation workers exposed to external #betta#-rays

    International Nuclear Information System (INIS)

    Piesch, E.; Boehm, J.; Heinzelmann, M.

    1983-01-01

    In radiation protection monitoring the need exists for an estimation of body dose due to external #betta#-rays, for instance if the #betta#-dose rate at the working area is expected to be high according to the data of source activity or room contamination, the indicated dose values of a personal dosemeter exceed the operational limit for the organ or tissue depth of interest, or a person was exposed to a significant dose. On behalf of the Federal Ministry of the Interior, Federal Republic of Germany, a guideline is now under preparation which offers a standardized concept of the estimation of #betta#-doses in personnel monitoring. The calculation models discussed here will be used as a basis for any case of external #betta#-irradiation where, in connection with the German Radiation Protection Ordinance, the ICRP dose equivalent limits are reached or the dosemeter readings are not representative for an individual exposure. The generalized concept discussed in the paper relates to: the calculation of #betta#-dose on the basis of source activity or spectral particle fluence and takes into account the special cases of point sources, area sources and volume sources; the estimation of body dose on the basis of calculated data or measured results from area or personnel monitoring, taking into account the dose equivalent in different depths of tissue, in particular the dose equivalent to the skin, the lens of the eye and other organs; and finally the estimation of skin dose due to the contamination of the skin surface. Basic reference data are presented in order to estimate the dose equivalent of interest which varies significantly in the #betta#-radiation field as a function of the maximum #betta#-energy, distance to the source, size of the source, activity per area for surface contamination and activity per volume for air contamination

  4. Estimation of dose to patients undergoing computed radiography x-ray examinations in some Khartoum hospitals

    International Nuclear Information System (INIS)

    Badri, Fatima Abulgasiem Abdulrhman

    2015-12-01

    This study was designed to evaluate the entrance surface air kerma to the patient during x-ray examination to (chest PA, lumbar spine AP and Lat, pelvis AP) by using computed radiography (CR) in different three hospitals in Khartoum. Three x-ray machines were covered. A total of 135 patients were evaluated. The entrance surface air kerma was calculated for each patient from the exposure parameters using cal dose software version 3.5. The obtained results showed that, the entrance surface air kerma range founded to be (0.28-1.59) for chest PA, (1.98-2.62) for lumbar spine and (0.438-2.47) for pelvis AP. The higher entrance surface air kerma for all projections were observed in Center 1, except for pelvis it is higher in center 2. And the lower entrance surface air kerma were observed in center 3. This study recommends that CR operator must to be used to achieve optimize the patient dose by use the best strategies available for reducing radiation dose, computed radiography must be used with high level of training for medical staff to reduce the dose, each radiology department should implement a patient dose measurement quality assurance programme, doses to the patients should be regularly monitored and the proposed national DRLs should be taken as guidance for optimization.(Author)

  5. Impact of Digital Imaging on Radiation Doses to the Patient During X-ray Examination of the Urinary Tract

    International Nuclear Information System (INIS)

    Sjoeholm, B.; Geijer, H.; Persliden, J.

    2005-01-01

    Purpose: To compare radiation doses given to patients undergoing IVU (intravenous urography) before and after digitalization of our X-ray department. Material and Methods: IVU examinations were monitored with dose area product meters before and after the X-ray department changed to digital techniques. The first step was a change from film-screen to storage phosphor plates, while the second step involved changing to a flat panel detector. Forty-two patients were included for the film-screen situation, 69 when using the storage phosphor plates, and 70 using the flat panel detector. Results: A dose reduction from 41.8 Gycm 2 to 31.5 Gycm 2 was achieved with the first step when the film-screen system was replaced with storage phosphor plates. A further reduction to 12.1 Gycm 2 was achieved using the flat panel detector. Conclusion: The introduction of the flat panel detectors made a considerable dose reduction possible Digital radiography, dosimetry, urinary

  6. Impact of Digital Imaging on Radiation Doses to the Patient During X-ray Examination of the Urinary Tract

    Energy Technology Data Exchange (ETDEWEB)

    Sjoeholm, B. [Oerebro Univ. Hospital (Sweden). Depts. of Medical Physics and Radiology; Geijer, H. [Oerebro Univ. (Sweden). Dept. of Physics; Persliden, J. [Linkoeping Univ. (Sweden). Dept. of Radiation Physics

    2005-10-01

    Purpose: To compare radiation doses given to patients undergoing IVU (intravenous urography) before and after digitalization of our X-ray department. Material and Methods: IVU examinations were monitored with dose area product meters before and after the X-ray department changed to digital techniques. The first step was a change from film-screen to storage phosphor plates, while the second step involved changing to a flat panel detector. Forty-two patients were included for the film-screen situation, 69 when using the storage phosphor plates, and 70 using the flat panel detector. Results: A dose reduction from 41.8 Gycm{sup 2} to 31.5 Gycm{sup 2} was achieved with the first step when the film-screen system was replaced with storage phosphor plates. A further reduction to 12.1 Gycm{sup 2} was achieved using the flat panel detector. Conclusion: The introduction of the flat panel detectors made a considerable dose reduction possible Digital radiography, dosimetry, urinary.

  7. Cosmic ray muons for spent nuclear fuel monitoring

    Science.gov (United States)

    Chatzidakis, Stylianos

    There is a steady increase in the volume of spent nuclear fuel stored on-site (at reactor) as currently there is no permanent disposal option. No alternative disposal path is available and storage of spent nuclear fuel in dry storage containers is anticipated for the near future. In this dissertation, a capability to monitor spent nuclear fuel stored within dry casks using cosmic ray muons is developed. The motivation stems from the need to investigate whether the stored content agrees with facility declarations to allow proliferation detection and international treaty verification. Cosmic ray muons are charged particles generated naturally in the atmosphere from high energy cosmic rays. Using muons for proliferation detection and international treaty verification of spent nuclear fuel is a novel approach to nuclear security that presents significant advantages. Among others, muons have the ability to penetrate high density materials, are freely available, no radiological sources are required and consequently there is a total absence of any artificial radiological dose. A methodology is developed to demonstrate the applicability of muons for nuclear nonproliferation monitoring of spent nuclear fuel dry casks. Purpose is to use muons to differentiate between spent nuclear fuel dry casks with different amount of loading, not feasible with any other technique. Muon scattering and transmission are used to perform monitoring and imaging of the stored contents of dry casks loaded with spent nuclear fuel. It is shown that one missing fuel assembly can be distinguished from a fully loaded cask with a small overlapping between the scattering distributions with 300,000 muons or more. A Bayesian monitoring algorithm was derived to allow differentiation of a fully loaded dry cask from one with a fuel assembly missing in the order of minutes and negligible error rate. Muon scattering and transmission simulations are used to reconstruct the stored contents of sealed dry casks

  8. On problems of the lens of the eye radiation dose monitoring

    Directory of Open Access Journals (Sweden)

    G. N. Kaydanovsky

    2016-01-01

    Full Text Available According to results of in-depth studies, the risk of the radiation-induced cataract is higher than it was considered earlier. In April 2011, ICRP released a statement on the tissue reactions. The statement recommends that for the case of for occupational exposure in planned exposure situations, an equivalent dose for the lens of the eye should be less than 20 mSv in a year, averaged over the defined periods of 5 years, with no single year exceeding the value of 50 mSv. In this regard, the new standard IAEA № GSR Part 3 provides the dose limit of 20 mSv in a year for occupational exposure for the lens of the eye. The dosimetric data on levels of exposure for personnel in the Russian Federation is practically absent. This paper performs a preliminary evaluation of equivalent dose for the lens of the eye for personnel working in X-ray operating rooms of medical facilities in Saint Petersburg and Kazan. This group of personnel was selected because of the fact that methodic of carrying out procedures forces medical staff to be not only in the zone of scattered radiation but also in the X-ray beam. This fact significantly increases exposure doses for the personnel. It is shown that actual annual dose can exceed the new dose limit (the highest recorded value Нр(3 in 3 months of work was 8,6 mSv. We made a conclusion on the necessity of the lens of the eye dose monitoring amongst interventional specialists on conditions that new limits will be established in the Russian Federation. The Russian and foreign dosimeters for measurement of individual dose equivalent for the lens of the eye Нр(3 which have been registered in the Russian State Register of Measuring Instruments, are descrivebed in the paper.

  9. Real-time electron-beam dose monitoring

    International Nuclear Information System (INIS)

    McKeown, J.

    1995-01-01

    A new technique to monitor the integrated dose that a product receives in an irradiation facility is determined by collecting the charge that passes through the product. The technique allows the absorbed dose to be monitored as the irradiation is taking place, i.e. on-line and in real time. The procedure will also provide a means of directly measuring the electron energy, independent of the accelerator control system. The irradiation plant operator can immediately detect a problem of inadequate electron energy and take appropriate action. Examples taken on the IMPELA trademark accelerator at the Iotron Irradiation Facility in Vancouver are presented

  10. Radiation doses for X-ray diagnosis teeth in dental medicine

    International Nuclear Information System (INIS)

    Direkov, Lyubomir

    2009-01-01

    X-rays are the first ionizing radiation, which are applied in medicine for diagnostic radiology and X-ray therapy. While in the beginning they are mainly used for X-ray photos of the chest /lungs and in severe fractures of the limbs, then in recent years they are widely applied in diagnostics of teeth in dental medicine. Considering that caries is a widespread disease, both in children and adults, and it requires repeated x-ray photographs of the damaged teeth for the individual, the total radiation doses, which reflect on people from the X-rays are at high values. In order to reduce external exposure to other organs /mainly thyroid gland/ by X-ray pictures of teeth, it should be used with special lead aprons with large coefficient of reduction. Keywords: doses of radiation, X-ray machines, dental, x-ray pictures of teeth, protection sources

  11. Dose Rate Determination from Airborne Gamma-ray Spectra

    DEFF Research Database (Denmark)

    Bargholz, Kim

    1996-01-01

    The standard method for determination of ground level dose rates from airborne gamma-ray is the integral count rate which for a constant flying altitude is assumed proportional to the dose rate. The method gives reasonably results for natural radioactivity which almost always has the same energy...

  12. Monochromatic x-rays for low-dose digital mammography: preliminary results.

    Science.gov (United States)

    Yoon, Kwon-Ha; Kwon, Young Man; Choi, Byoung-Jung; Son, Hyun Hwa; Ryu, Cheol Woo; Chon, Kwon Su; Park, Seong Hoon; Juhng, Sun Kwan

    2012-12-01

    The feasibility of using monochromatic x-ray imaging generated from an x-ray tube and a multilayer reflector for digital mammography with a low radiation dose was examined. A multilayer mirror was designed to select the x-ray peak with an energy of 21.5 keV generated from an x-ray tube with a tungsten target and was fabricated by the ion-beam sputtering deposition system. Monochromatic x-ray images were obtained from an experimental digital mammography setup with a scanning stage. The performance of the system was evaluated using a breast phantom, a spectrometer, and a radiation dosimeter. We measured the contrast-to-noise ratio and performed the 10% modulation function test to determine image quality and resolution. The monochromatic beam from the multilayer reflector had a full-width-at-half-maximum of 0.9 keV at 21.5 keV, and the reflectivity was 0.70, which was 90% of the designed value. The polychromatic and monochromatic x-rays showed radiation doses of 0.497 and 0.0415 mGy, respectively. The monochromatic x-ray image shows fibers, calcifications, and masses more clearly than the polychromatic x-ray images do. The image contrast of the monochromatic x-rays was 1.85 times higher than that of the polychromatic x-rays. The experimental mammography setup had a spatial resolution of 7 lp/mm with both x-rays. Monochromatic x-rays generated using a multilayer mirror may be a useful diagnostic tool for breast examination by providing high contrast imaging with a low radiation dose.

  13. The practical application of ICRP recommendations regarding dose-equivalent limits for workers to staff in diagnostic X-ray departments

    International Nuclear Information System (INIS)

    Gill, J.R.; Beaver, P.F.; Dennis, J.A.

    1980-01-01

    Members of hospital staff who work in the X-ray room with patients, wear lead aprons to protect their bodies. These aprons greatly reduce the radiation dose rate at the surface of the body underneath the apron, but do not give any protection to parts of the body not covered by the apron, especially the head, neck, arms and legs. The ICRP's system of dose limitation for non-uniform irradiation of the body has been applied to exposure of this kind and a simple formula has been derived that permits the calculation of a good approximation to the effective dose-equivalent, using two dosemeters. One dosemeter is worn at chest or waist level under the apron to monitor the dose-equivalent received by protected organs while the other is worn on the collar or forehead to monitor the head and neck. Evidence based on published data is presented that suggests that in work of this nature, contrary to earlier opinion, the limiting factor is the dose equivalent received by the organs of the head and neck. The implications of this conclusion for routine personal monitoring are discussed. (H.K.)

  14. Measurements of gamma-ray dose from a moderated 252Cf source

    International Nuclear Information System (INIS)

    McDonald, J.C.; Griffith, R.V.; Plato, P.; Miklos, J.

    1983-06-01

    The gamma-ray dose fraction from a moderated 252 Cf source was determined by using three types of dosimetry systems. Measurements were carried out in air at a distance of 35 cm from the surface of the moderating sphere (50 cm from the source which is at the center of the sphere) to the geometrical center of each detector. The moderating sphere is 0.8-mm-thick stainless steel shell filled with D 2 O and covered with 0.5 mm of cadmium. Measurements were also carried out with instruments and dosimeters positioned at the surface of a 40 cm x 40 cm x 15 cm plexiglass irradiation phantom whose front surface was also 35 cm from the surface of the moderating sphere. A-150 tissue-equivalent (TE) plastic ionization chambers and a TE proportional counter (TEPC) were used to measure tissue dose, from which the neutron dose equivalent was computed. The ratio of gamma-ray dose to the neutron dose equivalent was determined by using a relatively neutron-insensitive Geiger-Mueller (GM) counter and thermoluminescent dosimeters (TLD). In addition, the event-size spectrum measured by the TEPC was also used to compute the gamma-ray dose fraction. The average value for the ratio of gamma-ray dose to neutron dose equivalent was found to be 0.18 with an uncertainty of about +-18%

  15. Distribution and characteristics of gamma and cosmic ray dose rate in living environment

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Moriuchi, Shigeru

    1991-01-01

    A series of environmental radiation surveys was carried out from the viewpoint of characterizing the natural radiation dose rate distribution in the living environment, including natural and artificial ones. Through the analysis of the data obtained at numbers of places, several aspects of the radiation field in living environments were clarified. That is the gamma ray dose rate varies due to the following three dominant causes: 1) the radionuclide concentration of surrounding materials acting as gamma ray sources, 2) the spatial distribution of surrounding materials, and 3) the geometrical and shielding conditions between the natural gamma ray sources and the measured point; whereas, the cosmic ray dose rate varies due to the thickness of upper shielding materials. It was also suggested that the gamma ray dose rate generally shows an upward tendency, and the cosmic ray dose rate a downward one in artificial environment. This kind of knowledge is expected to serve as fundamental information for accurate and realistic evaluation of the collective dose in the living environment. (author)

  16. Quality control of thermoluminesce personal dose monitoring

    International Nuclear Information System (INIS)

    Shang Aiguo; He Wenchang; Zhao Fengtao

    2006-01-01

    In order to evaluate the influence factor to thermoluminesce personal dose monitoring result, the every question that can appear based on the fact was analyzed. The results show that the detector, annealing, measuring process can influence the monitoring result. It gives some measures to enhance monitoring quality. (authors)

  17. THE SWIFT/BAT HARD X-RAY TRANSIENT MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.; Pearlman, A. B.; Baumgartner, W. H.; Cummings, J. R. [Center for Research and Exploration in Space Science and Technology (CRESST) and NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Romano, P. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Kennea, J. A. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Bloom, J. S. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720-3411 (United States); Barthelmy, S. D.; Gehrels, N.; Lien, A. Y.; Markwardt, C. B.; Ukwatta, T. N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Palmer, D. M. [Los Alamos National Laboratory, B244, Los Alamos, NM 87545 (United States); Sakamoto, T. [Department of Physics and Mathematics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258 (Japan); Stamatikos, M. [Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)

    2013-11-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.

  18. The Swift/BAT Hard X-ray Transient Monitor

    Science.gov (United States)

    Krimm, H. A.; Holland, S. T.; Corbet, R.H.D.; Pearlman, A. B.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; hide

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as ne as 64 seconds. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the ux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public web page. Since 2005 February, 242 sources have been detected in the monitor, 149 of them persistent and 93 detected only in outburst. Among these sources, 16 were previously unknown and discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and ltering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries and present basic data analysis and interpretations for those sources with previously unpublished results.

  19. The Swift-BAT Hard X-Ray Transient Monitor

    Science.gov (United States)

    Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.; Pearlman, A. B.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; hide

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure.We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.

  20. THE SWIFT/BAT HARD X-RAY TRANSIENT MONITOR

    International Nuclear Information System (INIS)

    Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.; Pearlman, A. B.; Baumgartner, W. H.; Cummings, J. R.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Gehrels, N.; Lien, A. Y.; Markwardt, C. B.; Ukwatta, T. N.; Palmer, D. M.; Sakamoto, T.; Stamatikos, M.

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations

  1. 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)

  2. Biophysical Monitoring and dose response characteristics of irradiated hemoglobin

    International Nuclear Information System (INIS)

    Elshemey, W.M; Selim, N.S.; Desouky, O.

    2003-01-01

    The present work aims to move a step forward towards a deeper understanding of the scattering of x-ray, from lyophilized biological samples. Comparative study has been performed using LAXS and UV-visible spectrophotometry for monitoring the dose response characteristics of the hemoglobin molecule of irradiated blood. Blood samples were irradiated at doses ranging from 5 up to 100 Gy. Diluted hemoglobin solution was scanned in the UV- visible range (200-700 nm), and lyophilized hemoglobin was prepared for LAXS measurement. The radiation-induced changes in the hemoglobin structure have been evaluated. The LAXS profile of hemoglobin molecule is characterized by the presence of two peaks in the forward direction of scattering. These peaks were found to be sensitive to the variations in the molecular structure of a given sample. The obtained results suggest that the 1 s t peak, recorded at 4.65 o , is sensitive to the tertiary and quaternary structure of the globin part, while the major peak, recorded at 10.5 o , appeared to be related to its primary and secondary structure

  3. Monitoring variable X-ray sources in nearby galaxies

    Science.gov (United States)

    Kong, A. K. H.

    2010-12-01

    In the last decade, it has been possible to monitor variable X-ray sources in nearby galaxies. In particular, since the launch of Chandra, M31 has been regularly observed. It is perhaps the only nearby galaxy which is observed by an X-ray telescope regularly throughout operation. With 10 years of observations, the center of M31 has been observed with Chandra for nearly 1 Msec and the X-ray skies of M31 consist of many transients and variables. Furthermore, the X-ray Telescope of Swift has been monitoring several ultraluminous X-ray sources in nearby galaxies regularly. Not only can we detect long-term X-ray variability, we can also find spectral variation as well as possible orbital period. In this talk, I will review some of the important Chandra and Swift monitoring observations of nearby galaxies in the past 10 years. I will also present a "high-definition" movie of M31 and discuss the possibility of detecting luminous transients in M31 with MAXI.

  4. The relative biological effectiveness of 60Co γ-rays, 55 kVp X-rays, 250 kVp X-rays, and 11 MeV electrons at low doses

    International Nuclear Information System (INIS)

    Spadinger, I.; Palcic, B.

    1992-01-01

    The RBE of selected low-LET radiation modalities (55 kVp X- rays, 250 kVp X-rays, 60 Co γ-rays, and 11 MeV electrons) was investigated for survival of two cell lines (V79 and CHO). Detailed measurements were made in the 0 to 3 Gy dose range using an image cytometry device to accurately determine the number of cells assayed at each dose point. Data were also collected in the high dose range (0 to 10 Gy) using conventional counting and plating techniques. RBE values (#+- #1 SE) varied from 1.0±0.07 (V79 cells) and 1.2± 0.05 (CHO cells) at high doses to 1.3±0.07 (V79) and 1.4±0.1 (CHO) at low doses for 55 kVp X-rays, from 1.1±0.05 (V79) and 1.1±0.04 (CHO) at high doses to 1.1±0.06 (V79) and 1.2±0.2 (CHO) at low doses for 250 kVp X-rays, and from 1.1±0.08 (V79) and 1.0±0.04 (CHO) at high doses to 1.0±0.06 (V79) and 0.9±0.1 (CHO) at low doses for 11 MeV electrons. Only the low and high dose RBEs for 55 kVp X-rays relative to 60 Co γ-rays were significantly different. (author)

  5. TH-E-209-00: Radiation Dose Monitoring and Protocol Management

    International Nuclear Information System (INIS)

    2016-01-01

    Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.

  6. TH-E-209-00: Radiation Dose Monitoring and Protocol Management

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.

  7. 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)

  8. Monitoring of radiation exposure and registration of doses

    International Nuclear Information System (INIS)

    1993-01-01

    The Section 32 of the Finnish Radiation Act (592/91) defines the requirements to be applied to the monitoring of the radiation exposure and working conditions in Finland. The concepts relevant to the monitoring and guidelines for determining the necessity of the monitoring as well as its organizing are given in the guide. Instructions for reporting doses to the Dose Register of the Finnish Centre for Radiation and Nuclear Safety (STUK) are given, also procedures for situations leading to exceptional exposures are described. (9 refs.)

  9. Response of human lymphocytes to low gamma ray doses

    International Nuclear Information System (INIS)

    Vega Carrillo, HR; Banuelos Valenzuela, R; Manzanares Acuna, E; Sanchez-Rodriguez, S.H

    2001-01-01

    Radiation and non-radiation workers lymphocytes were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp25, Hsp60, Hsp70 and Hsp90; from these, only Hsp70 protein was detected before and after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 70.5 mGy gamma-ray dose, radiation worker's lymphocytes expressed more Hsp70 protein, than non-radiation workers' lymphocytes, indicating a larger tolerance to gamma rays (gamma tolerance), due to an adaptation process developed by their labor condition (Au)

  10. JEM-X: The X-ray monitor on INTEGRAL

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Carl; Lund, Niels; Westergaard, Niels Jørgen Stenfeldt

    2004-01-01

    The INTEGRAL X-ray monitor, JEM-X, (together with the two gamma ray instruments, SPI and IBIS) provides simultaneous imaging with arcminute angular resolution in the 3-35 keV band. The good angular resolution and low energy response of JEM-X plays an important role in the detection and identifica......The INTEGRAL X-ray monitor, JEM-X, (together with the two gamma ray instruments, SPI and IBIS) provides simultaneous imaging with arcminute angular resolution in the 3-35 keV band. The good angular resolution and low energy response of JEM-X plays an important role in the detection...

  11. Micro-X-ray absorption near edge structure as a suitable probe to monitor live organisms

    International Nuclear Information System (INIS)

    Oger, Phil M.; Daniel, I.; Simionovici, A.; Picard, A.

    2008-01-01

    X-ray spectroscopies are very powerful tools to determine the chemistry of complex dilute solutes in abiotic and biotic systems. We have assayed their suitability to monitor the chemistry of complex solutions in a live biotic system. The impact of the probe on cells was quantified for 4 different cellular organisms differing in their resistance level to environmental stresses. We show that none of the organisms tested can survive the radiation doses needed for the acquisition of meaningful spectroscopic data. Therefore, on one hand, X-ray spectroscopy cannot be applied to the monitoring of single cells, and cellular damages have to be taken into account in the interpretation of the evolution of such systems. On the other hand, due to the limited extension of X-ray induced cellular damages in the culture volume, it is possible to probe a population of live cells provided that the culture to beam probe ratio is large enough to minimize the impact of mortality on the evolution of the biological system. Our results suggest that it could be possible to probe the volume in the close vicinity of a cell without affecting its activity. Using this setup we could monitor the reduction of selenite by the X-ray sensitive bacterium, Agrobacterium tumefaciens strain C58, for 24 h. This method has a great potential to monitor the respiration of various metals, such as iron, manganese and arsenic, in situ under relevant environmental conditions by live microorganisms

  12. Micro-X-ray absorption near edge structure as a suitable probe to monitor live organisms

    Energy Technology Data Exchange (ETDEWEB)

    Oger, Phil M. [Laboratoire de Sciences de la Terre, UMR CNRS 5570, Ecole Normale Superieure de Lyon-Universite Claude Bernard Lyon 1, Lyon, F-69364 (France)], E-mail: poger@ens-lyon.fr; Daniel, I.; Simionovici, A.; Picard, A. [Laboratoire de Sciences de la Terre, UMR CNRS 5570, Ecole Normale Superieure de Lyon-Universite Claude Bernard Lyon 1, Lyon, F-69364 (France)

    2008-04-15

    X-ray spectroscopies are very powerful tools to determine the chemistry of complex dilute solutes in abiotic and biotic systems. We have assayed their suitability to monitor the chemistry of complex solutions in a live biotic system. The impact of the probe on cells was quantified for 4 different cellular organisms differing in their resistance level to environmental stresses. We show that none of the organisms tested can survive the radiation doses needed for the acquisition of meaningful spectroscopic data. Therefore, on one hand, X-ray spectroscopy cannot be applied to the monitoring of single cells, and cellular damages have to be taken into account in the interpretation of the evolution of such systems. On the other hand, due to the limited extension of X-ray induced cellular damages in the culture volume, it is possible to probe a population of live cells provided that the culture to beam probe ratio is large enough to minimize the impact of mortality on the evolution of the biological system. Our results suggest that it could be possible to probe the volume in the close vicinity of a cell without affecting its activity. Using this setup we could monitor the reduction of selenite by the X-ray sensitive bacterium, Agrobacterium tumefaciens strain C58, for 24 h. This method has a great potential to monitor the respiration of various metals, such as iron, manganese and arsenic, in situ under relevant environmental conditions by live microorganisms.

  13. Study of hard X-ray dose enhancement effects for some kinds of semiconductor devices

    CERN Document Server

    Guo Hong Xia; Chen Yu Sheng; Zhou Hui; He Chao Hui; Xie Ya Ning; Huang Yu Ying; He Wei; Hu Tian Dou

    2002-01-01

    Experimental results of X-ray dose enhancement effects are given for CMOS4069 and floating gate ROMs irradiated in Beijing Synchrotron Radiation Facility and in cobalt source. Shift of threshold voltage vs. total dose for CMOS4069 and the errors vs. total dose for 28f256 and 29c256 have been tested on line and the equivalent relation of total dose damage under the same accumulated dose is provided comparing the response of devices irradiated by X-ray and gamma-ray source. These results can be provided for X-ray radiation hardening technology as an effective evaluation data

  14. Gamma-Ray Doses Affected on Alfalfa (Medicago sativa L.)

    International Nuclear Information System (INIS)

    Zayed, E.M; Tarrad, M.M.; Abd El-Daem, G.A.N.A.

    2013-01-01

    Field experiments were conducted at the experimental from, Nuclear Research Center at Inshas. Atomic Energy Authority (AEA) at Egypt during 2011– 2012 growing seasons on alfalfa genotype. The aim of this investigation to evaluate the effect of different gamma ray doses (100-300 Gy) on the alfalfa yield and related traits. Seeds lots of alfalfa genotype were subjected to five gamma ray treatments (100,150,200,250 and 300 Gray). Over all cuts, the dose treatment 300 Gy increased the majority of studied traits i.e., plant height, No. of shoots/plant, fresh weight/plant, fresh yield/Fadden and dry weight yield/fed. The results observed indicated that. In addition, dose of 200 and 250 Gy increased No. of leaves /plant, No. of shoots/plant, stem diameter and fresh weight /plant. However, the plant dry weight was decreased by all doses used and over all cuts, but the dose of 100 and 150 Gy increased leaves /stem ratio. Meanwhile, the later cuts were more affected by irradiation treatments than the earlier ones. In general, the low doses had negative effects on yield traits, but, the relatively high doses exhibited an increase in yield traits

  15. The reduction methods of operator's radiation dose for portable dental X-ray machines.

    Science.gov (United States)

    Cho, Jeong-Yeon; Han, Won-Jeong

    2012-08-01

    This study was aimed to investigate the methods to reduce operator's radiation dose when taking intraoral radiographs with portable dental X-ray machines. Two kinds of portable dental X-ray machines (DX3000, Dexcowin and Rextar, Posdion) were used. Operator's radiation dose was measured with an 1,800 cc ionization chamber (RadCal Corp.) at the hand level of X-ray tubehead and at the operator's chest and waist levels with and without the backscatter shield. The operator's radiation dose at the hand level was measured with and without lead gloves and with long and short cones. The backscatter shield reduced operator's radiation dose at the hand level of X-ray tubehead to 23 - 32%, the lead gloves to 26 - 31%, and long cone to 48 - 52%. And the backscatter shield reduced operator's radiation dose at the operator's chest and waist levels to 0.1 - 37%. When portable dental X-ray systems are used, it is recommended to select X-ray machine attached with a backscatter shield and a long cone and to wear the lead gloves.

  16. Monitoring of radiation exposure and registration of doses

    International Nuclear Information System (INIS)

    1996-01-01

    The guide defines the concepts relevant to the monitoring of radiation exposure and working conditions and provides guidelines for determining the necessity of monitoring and subsequently organizing it. In addition, instructions are given for reporting doses to the Dose Register of the Finnish Centre for Radiation and Nuclear Safety (STUK). Also the procedures are described for situations leading to exceptional exposures. (10 refs., 1 tab.)

  17. Personal radiation monitoring and assessment of doses received by radiation workers (1991)

    International Nuclear Information System (INIS)

    Morris, N.D.

    1992-06-01

    The Australian Radiation Laboratory has operated a Personal Radiation Monitoring Service since the early 1930's so that people working with radiation can determine the radiation doses that they receive due to their occupation. Since late 1986, all persons monitored by the Service have been registered on a data base which maintains records of the doses received by each individual wearer. Ultimately, this data base will become a National Register of the doses received within Australia. At present, the Service regularly monitors approximately 20,000 persons, which is roughly 70 percent of those monitored in Australia, and maintains dose histories of over 35,000 people. The skin dose for occupationally exposed workers can be measured by using one of the four types of monitor issued by the Service: 1. Thermoluminescent Dosemeter (TLD monitor) 2. Finger TLD 3. Neutron Monitor 4. Special TLD. The technical description of the monitors is provided along with the method for calculating the radiation dose. 5 refs., 7 tabs., 4 figs

  18. Dose distribution calculation for in-vivo X-ray fluorescence scanning

    International Nuclear Information System (INIS)

    Figueroa, R. G.; Lozano, E.; Valente, M.

    2013-01-01

    In-vivo X-ray fluorescence constitutes a useful and accurate technique, worldwide established for constituent elementary distribution assessment. Actually, concentration distributions of arbitrary user-selected elements can be achieved along sample surface with the aim of identifying and simultaneously quantifying every constituent element. The method is based on the use of a collimated X-ray beam reaching the sample. However, one common drawback for considering the application of this technique for routine clinical examinations was the lack of information about associated dose delivery. This work presents a complete study of the dose distribution resulting from an in-vivo X-ray fluorescence scanning for quantifying biohazard materials on human hands. Absorbed dose has been estimated by means of dosimetric models specifically developed to this aim. In addition, complete dose distributions have been obtained by means of full radiation transport calculations in based on stochastic Monte Carlo techniques. A dedicated subroutine has been developed using the Penelope 2008 main code also integrated with dedicated programs -Mat Lab supported- for 3 dimensional dose distribution visualization. The obtained results show very good agreement between approximate analytical models and full descriptions by means of Monte Carlo simulations. (Author)

  19. Gamma-ray spectra and doses from the Little Boy replica

    International Nuclear Information System (INIS)

    Moss, C.E.; Lucas, M.C.; Tisinger, E.W.; Hamm, M.E.

    1984-01-01

    Most radiation safety guidelines in the nuclear industry are based on the data concerning the survivors of the nuclear explosions at Hiroshima and Nagasaki. Crucial to determining these guidelines is the radiation from the explosions. We have measured gamma-ray pulse-height distributions from an accurate replica of the Little Boy device used at Hiroshima, operated at low power levels near critical. The device was placed outdoors on a stand 4 m from the ground to minimize environmental effects. The power levels were based on a monitor detector calibrated very carefully in independent experiments. High-resolution pulse-height distributions were acquired with a germanium detector to identify the lines and to obtain line intensities. The 7631 to 7645 keV doublet from neutron capture in the heavy steel case was dominant. Low-resolution pulse-height distributions were acquired with bismuth-germanate detectors. We calculated flux spectra from these distributions using accurately measured detector response functions and efficiency curves. We then calculated dose-rate spectra from the flux spectra using a flux-to-dose-rate conversion procedure. The integral of each dose-rate spectrum gave an integral dose rate. The integral doses at 2 m ranged from 0.46 to 1.03 mrem per 10 13 fissions. The output of the Little Boy replica can be calculated with Monte Carlo codes. Comparison of our experimental spectra, line intensities, and integral doses can be used to verify these calculations at low power levels and give increased confidence to the calculated values from the explosion at Hiroshima. These calculations then can be used to establish better radiation safety guidelines. 7 references, 7 figures, 2 tables

  20. Personal radiation monitoring and assessment of doses received by radiation workers (1996)

    International Nuclear Information System (INIS)

    Morris, N.D.

    1996-12-01

    Since late 1986, all persons monitored by the Australian Radiation Laboratory have been registered on a data base which maintains records of the doses received by each individual wearer. At present, the Service regularly monitors approximately 30,000 persons, which is roughly 90 percent of those monitored in Australia, and maintains dose histories of over 75,000 people. The skin dose for occupationally exposed workers can be measured by using one of the five types of monitor issued by the Service: Thermoluminescent Dosemeter (TLD monitor), Finger TLD 3, Neutron Monitor, Special TLD and Environmental monitor. The technical description of the monitors is provided along with the method for calculating the radiation dose. 5 refs., 7 tabs., 5 figs

  1. Chest X ray effective doses estimation in computed radiography

    International Nuclear Information System (INIS)

    Abdalla, Esra Abdalrhman Dfaalla

    2013-06-01

    Conventional chest radiography is technically difficult because of wide in tissue attenuations in the chest and limitations of screen-film systems. Computed radiography (CR) offers a different approach utilizing a photostimulable phosphor. photostimulable phosphors overcome some image quality limitations of chest imaging. The objective of this study was to estimate the effective dose in computed radiography at three hospitals in Khartoum. This study has been conducted in radiography departments in three centres Advanced Diagnostic Center, Nilain Diagnostic Center, Modern Diagnostic Center. The entrance surface dose (ESD) measurement was conducted for quality control of x-ray machines and survey of operators experimental techniques. The ESDs were measured by UNFORS dosimeter and mathematical equations to estimate patient doses during chest X rays. A total of 120 patients were examined in three centres, among them 62 were males and 58 were females. The overall mean and range of patient dosed was 0.073±0.037 (0.014-0.16) mGy per procedure while the effective dose was 3.4±01.7 (0.6-7.0) mSv per procedure. This study compared radiation doses to patients radiographic examinations of chest using computed radiology. The radiation dose was measured in three centres in Khartoum- Sudan. The results of the measured effective dose showed that the dose in chest radiography was lower in computed radiography compared to previous studies.(Author)

  2. Assessment of patient radiation doses in chest X-ray examinations

    International Nuclear Information System (INIS)

    Orsini, S.; Scribano, V.S.; Merluzzi, F.; Tosca, L.

    1987-01-01

    The paper reports the initial results of a radioprotection programme for diagnostic radiology carried out in a major hospital in Milan. The data cover chest X-ray examinations. The dose values were obtained using different techniques, according to the specific diagnostic requirements in each departement. A wide radiation dose range was observed between the different techniques, with a ratio between maximum and minimum dose > 30 for the skin and the spine. The doses were however lower than those capable of inducing non-stochastic effects by about 10000 and were so low that the probability of a stochastics effect is minimal. Nevertheless, because chest X-rays are performed so frequently, it is recommended that radiologists take greater account of patient dose, as far as compatible with diagnostic requirements. Radiology technicians must strictly observe the regulations for radioprotection of the patient

  3. The survey of the surface doses of the dental x-ray machines

    International Nuclear Information System (INIS)

    Lee, Jae Seo; Kang, Byung Cheol; Yoon, Suk Ja

    2005-01-01

    The purpose of this study was to investigate variability of doses with same exposure parameters and evaluate radiographic density according to the variability of doses. Twenty-eight MAX-GLS (Shinhung Co, Seoul, Korea), twenty-one D-60-S (DongSeo Med, Seoul, Korea), and eleven REX-601 (Yoshida Dental MFG, Tokyo, Japan) dental x-ray machines were selected for this study. Surface doses were measured under selected combinations of tube voltage, tube current, exposure time, and constant distance 42 cm from the focal spot to the surface of the Multi-O-meter (Unfors Instrument, Billdal, Sweden). Radiographic densities were measured on the films at maximum, minimum and mean surface doses of each brand of x-ray units. With MAX-GLS, the maximum surface doses were thirteen to fourteen times as much as the minimum surfaces doses. With D-60-S, the maximum surface doses were three to eight times as much as the minimum surface doses. With REX-601, the maximum surface doses were six to ten times as much as the minimum surface doses. The differences in radiographic densities among maximum, mean, and minimum doses were significant (p<0.01). The surface exposure doses of each x-ray machine at the same exposure parameters were different within the same manufacturer's machines.

  4. A new type gamma-ray spectrum monitoring system

    CERN Document Server

    Cheng Bo; Zhou Jian Bin; Zhang Zhi Ming; Tong Yun Fu

    2002-01-01

    This new radiation monitoring system can be used to monitor the radiation of building materials and the radiation of atmosphere, to explore and evaluate rock for building in the field, and this system can be used to monitor the gamma irradiation near the nuclear establishments in the average situation and in the serious situation of the radiation incident have happened. The control core of this monitoring system is SCM-AT89C52, and gamma-ray sensing head consists of scintillator phi 50 mm x 50 mm NaI(Tl) and PMT GDB44. This system can be used to measure the whole gamma-ray spectrum of 256 channels

  5. Portable radiation monitors

    International Nuclear Information System (INIS)

    Masui, Kaoru; Ishikura, Takeshi; Inui, Daisuke

    2007-01-01

    This paper presents an overview of typical portable radiation monitors and introduces Fuji Electric's latest models. The overview describes the types, uses and performance of ion chamber survey meters, GM survey meters and neutron ambient dose equivalent rate meters. Fuji Electric's new model of a wide-energy-range X/gamma ray survey meter which measures low energy X-rays up to 8 keV, a battery-powered environmental dosemeter system which measures dose history and is capable of continuous measurement with batteries over a year, and a portable monitoring post which measures dose rates from background to 10 8 nGy/h and transmits data by cellular phone are introduced, and their specifications and performance are described. (author)

  6. Monte Carlo simulation of dose enhancement effect of X-ray at Au/Si interface

    International Nuclear Information System (INIS)

    Wu Zhengxin; He Chengfa; Lu Wu; Guo Qi; Yu Xin; Zhang Lei; Deng Wei; Zheng Qiwen; ARKIN Abulim

    2013-01-01

    Background: The dose enhancement factor of X-ray was found in 1970s, because of its bad damage to electronic devices. Purpose: This paper is mainly to calculate the dose-enhancement factor at Au/Si interfaces. Methods: The gradient distribution of dose with X-rays has been studied at and near the interface of Au/Si by Monte-Carlo simulation of particle transportation. The mechanism of dose enhancement is discussed based on the principles of interaction of photon with matter. A 3D Au/Si model has been established by MCNP5 program and the dose-enhancement factors of different thicknesses Au/Si interfaces were calculated by Monte Carlo method. Results: The calculated results demonstrate that there exists a stronger dose-enhancement in the Si side near the interface when the energy of X-ray is 30-300 keV. Conclusions: When the thickness of Au is 0-10 μm, dose-enhancement factor of X-ray increases along with the increase of the thickness of Au, when the thickness of Au exceeds 10 μm, dose-enhancement factor of X-ray decreases along with the increase of the thickness of Au. (authors)

  7. The effect of well-characterized, very low-dose x-ray radiation on fibroblasts.

    Science.gov (United States)

    Truong, Katelyn; Bradley, Suzanne; Baginski, Bryana; Wilson, Joseph R; Medlin, Donald; Zheng, Leon; Wilson, R Kevin; Rusin, Matthew; Takacs, Endre; Dean, Delphine

    2018-01-01

    The purpose of this study is to determine the effects of low-dose radiation on fibroblast cells irradiated by spectrally and dosimetrically well-characterized soft x-rays. To achieve this, a new cell culture x-ray irradiation system was designed. This system generates characteristic fluorescent x-rays to irradiate the cell culture with x-rays of well-defined energies and doses. 3T3 fibroblast cells were cultured in cups with Mylar® surfaces and were irradiated for one hour with characteristic iron (Fe) K x-ray radiation at a dose rate of approximately 550 μGy/hr. Cell proliferation, total protein analysis, flow cytometry, and cell staining were performed on fibroblast cells to determine the various effects caused by the radiation. Irradiated cells demonstrated increased proliferation and protein production compared to control samples. Flow cytometry revealed that a higher percentage of irradiated cells were in the G0/G1 phase of the cell cycle compared to control counterparts, which is consistent with other low-dose studies. Cell staining results suggest that irradiated cells maintained normal cell functions after radiation exposure, as there were no qualitative differences between the images of the control and irradiated samples. The result of this study suggest that low-dose soft x-ray radiation might cause an initial pause, followed by a significant increase, in proliferation. An initial "pause" in cell proliferation could be a protective mechanism of the cells to minimize DNA damage caused by radiation exposure. The new cell irradiation system developed here allows for unprecedented control over the properties of the x-rays given to the cell cultures. This will allow for further studies on various cell types with known spectral distribution and carefully measured doses of radiation, which may help to elucidate the mechanisms behind varied cell responses to low-dose x-rays reported in the literature.

  8. Individual dose monitoring of occupational exposure in nuclear industry system (1991-2000)

    International Nuclear Information System (INIS)

    Yang Lianzhen; Ma Jizeng; Li Taosheng

    2005-01-01

    The summary and main results of individual dose monitoring (1990-2000) from occupational exposure in China Nuclear Industry System are presented in this paper. During ten years, the external collective effective dose to workers in seven plants (not uranium mines and processing mills) and institutes is 98.48 person ·Sv, the per capita effective dose is 1.97 mSv. The general situation for individual dose monitoring from internal exposure is also introduced. The annual average committed effective dose is less than 5.0 mSv. The individual dose monitoring results (1991-1992) for occupational exposure from Uranium mines and processing mills are depicted. In the end, the individual dose monitoring data in nuclear industry system are preliminarily analysed. (authors)

  9. Dose Rate and Mass Attenuation Coefficients of Gamma Ray for Concretes

    CERN Document Server

    Abdel-Latif, A A; Kansouh, W A; El-Sayed, F H

    2003-01-01

    This work is concerned with the study of the leakage gamma ray dose and mass attenuation coefficients for ordinary, basalt and dolomite concretes made from local ores. Concretes under investigation were constructed from gravel, basalt and dolomite ores, and then reconstructed with the addition of 3% steel fibers by weight. Measurements were carried out using a collimated beam from sup 6 sup 0 Co gamma ray source and sodium iodide (3x3) crystal with the genie 2000 gamma spectrometer. The obtained fluxes were transformed to gamma ray doses and displayed in the form of gamma ray dose rates distribution. The displayed curves were used to estimate the linear attenuation coefficients (mu), the relaxation lengths (lambda), half value layer (t sub 1 /2) and tenth value layer (t sub 1 /10). Also, The total mass attenuation coefficients of gamma ray have been calculated to the concerned concretes using XCOM (version 3.1) program and database elements cross sections from Z=1 to 100 at energies from 10 keV to 100 MeV. In...

  10. Additional radiation dose to population due to X-ray diagnostic procedures

    International Nuclear Information System (INIS)

    Chougule, A.

    2006-01-01

    Full text of publication follows: Discovery of X rays has revolutionised the medical diagnosis but the fact that the diagnostic radiological procedures contribute about 80 to 90 % of the radiation dose to population as compared to other man made radiation sources cannot be ignored especially when X ray diagnostic facilities are being made available to larger section of the society. The estimated frequency of radiological procedures in India is 12,000 procedures/ year/100,000 population, though it is quite less as compared to developed countries, its increasing day by day. As part of the project, a radiation protection survey of X ray installations and patient radiation dose measurement during various radiological procedures was undertaken. 193 X ray installations were surveyed and the radiation doses received by the patient during various radiological procedure was measured. For measurement of radiation doses, CaSO 4 : Dy thermoluminescence (T.L.) discs of size 13.3 mm diameter and 0.8 mm thickness were used. Pre annealed T.L. discs were fixed by adhesive tape on the patient skin at the center of entrance beam before the exposure. After exposure the T.L. discs were estimated f or entrance skin dose during that particular projection/ examination. 10,000 measurements at different centers during various radiological procedures were done. It was found that chest radiography accounts for 37 % of all radiological procedures and further it was observed that 70 % of the chest X rays were normal with out any pathology indicating scope for curtailing the unwarranted radiological procedures. The special investigations like barium swallow, barium meal and fallow through accounts for about 1.5 % of the total radiological procedures. The entrance skin dose [E.S.D.] during chest radiography was 0.3 + 0.1 mGy where as during K.U.B. and cervical spine radiography it was 6.2 + 1.1 mGy and 5.1 + 0.9 mGy respectively. The details of frequency of various radiological procedures and the

  11. γ-ray dose rate effect in DNA double-strand break repair deficient murine cells

    International Nuclear Information System (INIS)

    Li Liya; Li Peiwen

    2002-01-01

    Objective: To analyze the dose rate effect and potentially lethal damage repair in DNA double-strand break repair deficient murine cells (SCID) irradiated by γ-ray. Methods: The wild type (CB.17+/+) and SCID cells were exposed to γ-ray at high and low dose rates. The high dose rate exposure was fractionated into two equal doses at 24 h intervals. The survival rates of irradiated cells were calculated by clone-forming analysis. Results: When γ-ray was given to wild type (CB.17+/+) cells in two fractions at 24 h intervals, the survival rate was significantly higher than that when the same total dose was given singly. In contrast, there was no difference in the survival rates between the single and fractionated exposure in SCID cells. SCID cells were more sensitive than CB.17+/+ cells to both low and high dose rates γ-ray exposure for cell killing. The survival rate by low dose rate exposure was significantly higher than that by high dose rate exposure, not only in CB.17+/+ cells but also in SCID cells. Conclusions: SCID cells are deficient in repairing γ-ray induced double-strand breaks. There is dose rate effect in both SCID and CB.17+/+ cells

  12. Cosolvent-free polymer gel dosimeters with improved dose sensitivity and resolution for x-ray CT dose response

    Energy Technology Data Exchange (ETDEWEB)

    Chain, J N M; McAuley, K B [Department of Chemical Engineering, Queen' s University, Kingston, K7L 3N6 (Canada); Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria, V8W 3P6 (Canada); Schreiner, L J, E-mail: kim.mcauley@chee.queensu.ca [Cancer Centre of Southeastern Ontario, Kingston, K7L 5P9 (Canada)

    2011-04-07

    This study reports new N-isopropylacrylamide (NIPAM) polymer gel recipes with increased dose sensitivity and improved dose resolution for x-ray CT readout. NIPAM can be used to increase the solubility of N, N'-methylenebisacrylamide (Bis) in aqueous solutions from approximately 3% to 5.5% by weight, enabling the manufacture of dosimeters containing up to 19.5%T, which is the total concentration of NIPAM and Bis by weight. Gelatin is shown to have a mild influence on dose sensitivity when gels are imaged using x-ray CT, and a stronger influence when gels are imaged optically. Phantoms that contain only 3% gelatin and 5 mM tetrakis hydroxymethyl phosphonium chloride are sufficiently stiff for dosimetry applications. The best cosolvent-free gel formulation has a dose sensitivity in the linear range ({approx}0.88 H Gy{sup -1}) that is a small improvement compared to the best NIPAM-based gels that incorporate isopropanol as a cosolvent ({approx}0.80 H Gy{sup -1}). This new gel formulation results in enhanced dose resolution ({approx}0.052 Gy) for x-ray CT readout, making clinical applications of this imaging modality more feasible.

  13. Cosolvent-free polymer gel dosimeters with improved dose sensitivity and resolution for x-ray CT dose response

    International Nuclear Information System (INIS)

    Chain, J N M; McAuley, K B; Jirasek, A; Schreiner, L J

    2011-01-01

    This study reports new N-isopropylacrylamide (NIPAM) polymer gel recipes with increased dose sensitivity and improved dose resolution for x-ray CT readout. NIPAM can be used to increase the solubility of N, N'-methylenebisacrylamide (Bis) in aqueous solutions from approximately 3% to 5.5% by weight, enabling the manufacture of dosimeters containing up to 19.5%T, which is the total concentration of NIPAM and Bis by weight. Gelatin is shown to have a mild influence on dose sensitivity when gels are imaged using x-ray CT, and a stronger influence when gels are imaged optically. Phantoms that contain only 3% gelatin and 5 mM tetrakis hydroxymethyl phosphonium chloride are sufficiently stiff for dosimetry applications. The best cosolvent-free gel formulation has a dose sensitivity in the linear range (∼0.88 H Gy -1 ) that is a small improvement compared to the best NIPAM-based gels that incorporate isopropanol as a cosolvent (∼0.80 H Gy -1 ). This new gel formulation results in enhanced dose resolution (∼0.052 Gy) for x-ray CT readout, making clinical applications of this imaging modality more feasible.

  14. Radiation Dose Measurements in Routine X Ray Examinations

    International Nuclear Information System (INIS)

    Osman, H.; Sulieman, A.; Suliman, I.I.; Sam, A.K.

    2011-01-01

    The aim of current study was to evaluate patients radiation dose in routine X-ray examinations in Omdurman teaching hospital Sudan.110 patients was examined (134) radiographs in two X-ray rooms. Entrance surface doses (ESDs) were calculated from patient exposure parameters using DosCal software. The mean ESD for the chest, AP abdomen, AP pelvis, thoracic spine AP, lateral lumber spine, anteroposterior lumber spine, lower limb and for the upper limb were; 231±44 Gy,453± 29 Gy, 567±22 Gy, 311±33 Gy,716±39 Gy, 611±55 Gy,311±23 Gy, and 158±57 Gy, respectively. Data shows asymmetry in distribution. The results of were comparable with previous study in Sudan.

  15. X-ray tube monitor apparatus

    International Nuclear Information System (INIS)

    Holland, W.P.; Pellergrino, A.

    1981-01-01

    An x-ray tube with a rotating anode target is provided with a detector of x-rays located outside a port of a housing of the tube and positioned at or near a tangent line to the radiating surface for observing variations in the radiation intensity due to rotation of the target, the variations being pronounced due to the heel effect of the radiation pattern. The x-ray detector can employ a scintillation material and be coupled by a light guide to a photodetector which is removed from the path of the radiation and detects scintillations of the x-ray detector. Alternatively, the photodetector and light pipe may be replaced by a detector of germanium, silicon or an ion chamber which converts x-ray photons directly to an electric current. An electronic unit determines the speed of rotation from the electric signal and can also, by fourier transform and signature analysis techniques, monitor the state of the radiating surface. (author)

  16. Individual external monitoring system for gamma and X ray evaluation of the individual dose equivalent 'HP(10)', utilizing a photographic dosimetry technique

    International Nuclear Information System (INIS)

    Santoro, Christiana; Filho, Joao Antonio

    2008-01-01

    Full text: Individual monitoring evaluates external sources of ionizing radiation X, γ, β and n, to which workers are occupationally exposed, for ensuring safe and acceptable radiological conditions in their places of employment. The dose received by workers should attend the limits authorized by national regulatory organs. Nowadays, there are two radiometric unit systems, based on resolutions of the National Nuclear Energy Commission (NNEC) and the International Commission on Radiation Units and Measurements (ICRU); in the conventional (NNEC) system, the doses received by workers are evaluated through the individual dose H x , where dosemeters used on surface of thorax are calibrated in terms of air kerma; in the recent system (ICRU), the doses are evaluated through the individual dose equivalent H P (d), where dosemeters are calibrated in terms of dose from phantom. The recent system improves the method of evaluation, by taking into account the scattering effect and absorption of radiation in the human body. This work adapts a photographic dosimetry service to the recent ICRU publications, for evaluation of individual monitoring, in function of the individual dose equivalent H P (10) of strong penetrating radiation. For this, a methodology based on linear programming and determination of calibration curves is used for radiation capacities, wide (W) and narrow (N) spectra, as described by the International Organization for Standardization (ISO 4037-1, 1995). These calibration curves offer better accuracy in the determination of doses and energy, which will improve the quality of the service given to society. The results show that the values of individual dose equivalent, evaluated at intervals of 0.2 to 200 mSv, have lower significant uncertainties (10%) than those recommended by the ICRP 75, for individual monitoring; therefore, the evaluation system for developed doses attends the new recommendations proposed by International Commissions. From what has been

  17. Specific gamma-ray dose constants for nuclides important to dosimetry and radiological assessment

    International Nuclear Information System (INIS)

    Unger, L.M.; Trubey, D.K.

    1982-05-01

    Tables of specific gamma-ray dose constants (the unshielded gamma-ray dose equivalent rate at 1 m from a point source) have been computed for approximately 500 nuclides important to dosimetry and radiological assessment. The half life, the mean attenuation coefficient, and thickness for a lead shield providing 95% dose equivalent attenuation are also listed

  18. Dose calculation of X-ray in medium

    International Nuclear Information System (INIS)

    Liu Yanmei; Xue Dingyu; Xu Xinhe; Chen Zhen; Dong Zaili

    2006-01-01

    The photon transportation in radiotherapy is studied based on Monte Carlo method. The dose calculation based on the MC simulation package DPM has been carried out, and the results have been visualized using MEX technology of Matlab. The dose results of X-ray in homogeneity and inhomogeneity medium have been compared with experimental data and those of other MC simulation package, and these results all agree. The calculation method we proposed has the advantage of high speed and good accuracy, therefore, is applicable in practice. (authors)

  19. Real-time eye lens dose monitoring during cerebral angiography procedures

    Energy Technology Data Exchange (ETDEWEB)

    Safari, M.J.; Wong, J.H.D.; Kadir, K.A.A.; Ng, K.H. [University of Malaya, Department of Biomedical Imaging, Faculty of Medicine, Kuala Lumpur (Malaysia); University of Malaya, University of Malaya Research Imaging Centre (UMRIC), Faculty of Medicine, Kuala Lumpur (Malaysia); Thorpe, N.K.; Cutajar, D.L.; Petasecca, M.; Lerch, M.L.F.; Rosenfeld, A.B. [University of Wollongong, Centre for Medical Radiation Physics (CMRP), Wollongong, NSW (Australia)

    2016-01-15

    To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures. Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures. The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R{sup 2}) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AK{sub L}: 0.93, AK{sub F}: 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions. The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose. (orig.)

  20. Real-time eye lens dose monitoring during cerebral angiography procedures

    International Nuclear Information System (INIS)

    Safari, M.J.; Wong, J.H.D.; Kadir, K.A.A.; Ng, K.H.; Thorpe, N.K.; Cutajar, D.L.; Petasecca, M.; Lerch, M.L.F.; Rosenfeld, A.B.

    2016-01-01

    To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures. Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures. The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R 2 ) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AK L : 0.93, AK F : 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions. The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose. (orig.)

  1. Dose properties of x-ray beams produced by laser-wakefield-accelerated electrons

    International Nuclear Information System (INIS)

    Kainz, K K; Hogstrom, K R; Antolak, J A; Almond, P R; Bloch, C D

    2005-01-01

    Given that laser wakefield acceleration (LWFA) has been demonstrated experimentally to accelerate electron beams to energies beyond 25 MeV, it is reasonable to assess the ability of existing LWFA technology to compete with conventional radiofrequency linear accelerators in producing electron and x-ray beams for external-beam radiotherapy. We present calculations of the dose distributions (off-axis dose profiles and central-axis depth dose) and dose rates of x-ray beams that can be produced from electron beams that are generated using state-of-the-art LWFA. Subsets of an LWFA electron energy distribution were propagated through the treatment head elements (presuming an existing design for an x-ray production target and flattening filter) implemented within the EGSnrc Monte Carlo code. Three x-ray energy configurations (6 MV, 10 MV and 18 MV) were studied, and the energy width ΔE of the electron-beam subsets varied from 0.5 MeV to 12.5 MeV. As ΔE increased from 0.5 MeV to 4.5 MeV, we found that the off-axis and central-axis dose profiles for x-rays were minimally affected (to within about 3%), a result slightly different from prior calculations of electron beams broadened by scattering foils. For ΔE of the order of 12 MeV, the effect on the off-axis profile was of the order of 10%, but the central-axis depth dose was affected by less than 2% for depths in excess of about 5 cm beyond d max . Although increasing ΔE beyond 6.5 MeV increased the dose rate at d max by more than 10 times, the absolute dose rates were about 3 orders of magnitude below those observed for LWFA-based electron beams at comparable energies. For a practical LWFA-based x-ray device, the beam current must be increased by about 4-5 orders of magnitude. (note)

  2. Organ doses and effective doses in some medical and industrial applications

    International Nuclear Information System (INIS)

    Keshavkumar, Biju

    2000-01-01

    The ICRP recommends radiation protection standards for the safe use of radiation and also prescribes the radiation protection quantities and periodically reviews them. In this context, the quantities like organ doses and effective doses are defined by ICRP. In this work we calculate these quantities and hence the conversion functions for the industrial radiation sources and those for CT and diagnostic X-ray exposures. Workers who are occupationally exposed to radiation are regularly monitored to evaluate the radiation dose received by them. It is quite possible that in an accident situation, the worker involved in the accident might not have worn a personal monitor, popularly known as the monitoring badge. In addition, even some non radiation workers (who are obviously not monitored) may also have received exposure. Under these circumstances, the persons involved are interviewed, the accident site inspected, and on the basis of realistic assumptions, the likely doses received by the exposed persons are estimated

  3. Measurements of X ray absorbed doses to dental patients in two dental X ray units in Nigeria

    International Nuclear Information System (INIS)

    Ogundare, F.O.; Oni, O.M.; Balogun, F.A.

    2002-01-01

    Measurements of absorbed doses from radiographic examinations to various anatomical sites in the head and neck of patients with an average age of 45 years using intra-oral dental radiography have been carried out. LiF (TLD-100) dosemeters were used for the measurements of the absorbed dose. The measured absorbed doses to the various anatomical sites in the two units are reported, discussed and compared with results from the literature. Quality control measurements were also performed using a Victoreen quality control test device on the X ray units. The tube voltage accuracies for the two units were found to be within acceptable limits (less than ±10%). On the other hand the exposure time accuracies for these units have large deviations (>20%). These results and those that have been reported in the literature may be an indication that high patient doses are common in most dental X ray centres and countries. As a result of this, regular compliance and performance checks of dental diagnostic X ray equipment are essential in order to ensure proper performance and to minimise unnecessary patient and operator doses. (author)

  4. Radiation dose and radiation risk to foetuses and newborns during X-ray examinations

    Energy Technology Data Exchange (ETDEWEB)

    Kettunen, A. [Oulu Univ. (Finland)

    2004-05-01

    The purpose of this study is to determine the way in which the demands set by degree 423/2000 by the Ministry of Social Affairs and Health are fulfilled with respect to the most radiosensitive groups, the foetus and the child, by estimating the radiation dose and radiation risk to the foetus from x-ray examinations of an expectant mother's pelvic region, finding out the practice involved in preventing doses to embryos and foetuses and assessing dose practices in cases where an embryo or foetus is or shall be exposed, and by estimating radiation dose and risk due to the radiation received by a new-born being treated in a paediatric intensive care unit. No statistics are available in Finland to indicate how many x-ray examinations of the pelvic region and lower abdomen are made to pregnant patients or to show the dose and risk to the foetus due these examinations. In order to find out the practices in radiological departments concerning the pelvic x-ray examination of fertile woman and the number of foetuses exposed, a questionnaire was sent to all radiation safety officers responsible for the safe use of radiation (n = 290). A total of 173 questionnaires were returned. This study recorded the technique and Dose-Area Product of 118 chest examinations of newborns in paediatric intensive care units. Entrance surface doses and effective doses were calculated separately to each newborn. Based on the patient records, the number of all x-ray examinations during the study was calculated and the effective doses were estimated retrospectively to each child. The radiation risk was estimated both for the foetuses and for the newborns. According to this study, it is rare in Finland to expose a pregnant woman to radiation. On the other hand, with the exception of pelvimetry examinations, there are no compiled statistics concerning the number of pelvic x-ray examinations of a pregnant woman. There was no common practice on how to exclude the possibility of pregnancy. The dose

  5. Radiation dose and radiation risk to foetuses and newborns during X-ray examinations

    International Nuclear Information System (INIS)

    Kettunen, A.

    2004-05-01

    The purpose of this study is to determine the way in which the demands set by degree 423/2000 by the Ministry of Social Affairs and Health are fulfilled with respect to the most radiosensitive groups, the foetus and the child, by estimating the radiation dose and radiation risk to the foetus from x-ray examinations of an expectant mother's pelvic region, finding out the practice involved in preventing doses to embryos and foetuses and assessing dose practices in cases where an embryo or foetus is or shall be exposed, and by estimating radiation dose and risk due to the radiation received by a new-born being treated in a paediatric intensive care unit. No statistics are available in Finland to indicate how many x-ray examinations of the pelvic region and lower abdomen are made to pregnant patients or to show the dose and risk to the foetus due these examinations. In order to find out the practices in radiological departments concerning the pelvic x-ray examination of fertile woman and the number of foetuses exposed, a questionnaire was sent to all radiation safety officers responsible for the safe use of radiation (n = 290). A total of 173 questionnaires were returned. This study recorded the technique and Dose-Area Product of 118 chest examinations of newborns in paediatric intensive care units. Entrance surface doses and effective doses were calculated separately to each newborn. Based on the patient records, the number of all x-ray examinations during the study was calculated and the effective doses were estimated retrospectively to each child. The radiation risk was estimated both for the foetuses and for the newborns. According to this study, it is rare in Finland to expose a pregnant woman to radiation. On the other hand, with the exception of pelvimetry examinations, there are no compiled statistics concerning the number of pelvic x-ray examinations of a pregnant woman. There was no common practice on how to exclude the possibility of pregnancy. The dose to a

  6. 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

  7. Effects of low X-ray doses in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Jordan, A.; Laskowski, W.

    1987-01-01

    Three strains of Saccharomyces cerevisiae with different capacities for repair of radiation damage (RAD, rad18, and rad52) have been tested for their colony forming ability (CFA) and growth rates after application of small X-ray doses from 3.8 mGy to 40 Gy. There was no reproducible increase in CFA observable after application of doses between 3.8 mGy and 4.7 Gy.X-ray doses of 40 Gy causing an inactivation of CFA from 90% to 50%, depending on the repair capacity of the strains used, caused a reduced increase in optical density during 2 h buffer treatment in comparison to unirradiated cells. This reduction however, is reversible as soon as the cells are transferred into nutrient medium. One hour after transfer into growh medium the portions of cells with large buds (Gs and M phase) and cells with small buds (S phase) are drastically different in irradiated cells from those obtained in unirradiated cells. The time necessary for separation of mother and daughter cells is prolonged by X-ray irradiation and the formation of new buds is retarded. (orig.)

  8. Area and environmental gamma dose monitoring at PINSTECH

    International Nuclear Information System (INIS)

    Javed, M.; Awan, M.A.; Ahmad, S.; Afsar, M.; Orfi, S.D.

    1986-11-01

    Radiation dose monitoring of various radioactive laboratories including PARR building, radioactive waste disposal area and the environment upto initial peripheral limits of PINSTECH has been carried out by TLD's installed at different locations. Average dose rates in terms of percentage of dose limits have been compiled. The results for the year 1985 have been discussed in this report. (author)

  9. An investigation of dose changes for therapeutic kilovoltage x-ray beams with underlying lead shielding

    International Nuclear Information System (INIS)

    Hill, Robin; Healy, Brendan; Holloway, Lois; Baldock, Clive

    2007-01-01

    Kilovoltage x-ray beams are used to treat cancer on or close to the skin surface. Many clinical cases use high atomic number materials as shielding to reduce dose to underlying healthy tissues. In this work, we have investigated the effect on both the surface dose and depth doses in a water phantom with lead shielding at depth in the phantom. The EGSnrc Monte Carlo code was used to simulate the water phantom and to calculate the surface doses and depth doses using primary x-ray beam spectra derived from an analytical model. The x-ray beams were in the energy range of 75-135 kVp with field sizes of 2, 5 and 8 cm diameter. The lead sheet was located beneath the water surface at depths ranging from 0.5-7.5 cm. The surface dose decreased as the lead was positioned closer to the water surface and as the field size was increased. The variation in surface dose as a function of x-ray beam energy was only small but the maximum reduction occurred for the 100 kVp x-ray beam. For the 8 cm diameter field with the lead at 1 cm depth and using the 100 kVp x-ray beam, the surface dose was reduced to 0.898 of the surface dose in the water phantom only. Measured surface dose changes, using a Farmer-type ionization chamber, agreed with the Monte Carlo calculated doses. Calculated depth doses in water with a lead sheet positioned below the surface showed that the dose fall-off increased as the lead was positioned closer to the water surface as compared to the depth dose in the water phantom only. Monte Carlo calculations of the total x-ray beam spectrum at the water surface showed that the total fluence decreased due to a reduction in backscatter from within the water and very little backscatter from the lead. The mean energy of the x-ray spectrum varied less than 1 keV, with the lead at 1 cm beneath the water phantom surface. As the Monte Carlo calculations showed good agreement with the measured results, this method can be used to verify surface dose changes in clinical situations

  10. 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)

  11. X-rays individual dose assessment using TLD dosimeters

    International Nuclear Information System (INIS)

    Salas, Carlos

    2008-01-01

    This paper describes the methodology used in Embalse NPP for measuring individual X-ray dose in dentists and radiologists, who work in areas near the plant. Personnel is provided with TLD personal dosimeters for thoracic use, as well as TLD ring dosimeters. This individual X-ray dosimetry is fundamental in order to know the effective energy coming from the radiation field, since the dosimetry factors depend on it. On the other hand, the response of the TLD crystals also depends of the effective energy; this accentuates the problem when assessing the individual dose. The X-ray dosimeter must simultaneously determine the value of the effective energy and the corresponding dose value. The basic principle for determining effective energy is by using at least two different TLD materials covered by filters of different thickness. The TLD materials used have totally energy responses. Therefore, different readouts from each of the crystals are obtained. The ratio between both readouts provides a factor that depends of the effective energy but that is 'independent' from the exposure values irradiated to the dosimeter. The Personal TLD dosimeter currently in use is Bicron-Harshaw. It comprises a carrier model 8807. This carrier contains a card model 2211 which groups two TLD 200 crystals and two TLD 100 crystals. It has internal filters at each side of the TLD 200 crystals. The periodical calibration of these dosimeters consists in the irradiation of some dosimeters with different X-ray energy beams in the National Atomic Energy Commission (CNEA). This dosimeter was used, by the National Regulatory Authority (ARN) in several comparisons, always getting satisfactory results. (author)

  12. The measurement of patient doses from diagnostic x-rays

    International Nuclear Information System (INIS)

    Morris, N.D.; Solomon, S.B.

    1980-06-01

    As part of the National Health and Medical Research Council survey to determine the genetic and mean bone-marrow doses to the Australian population from the medical, dental and chiropractic uses of radiation sources, doses to patients undergoing X-ray diagnostic procedures were evaluated. The doses were measured using capsules of LiF or CaF 2 :Dy thermoluminescent dosemeters (TLD). The evaluation of the TLD measurements is described and the mean values of the skin doses for patients undergoing various radiographic examinations in Australia in 1970 are presented

  13. Collective effective dose in Europe from x-ray and nuclear medicine procedures

    International Nuclear Information System (INIS)

    Bly, R.; Jaervinen, H.; Jahnen, A.; Olerud, H.; Vassileva, J.; Vogiatzi, S.

    2015-01-01

    Population doses from radiodiagnostic (X-ray and nuclear medicine) procedures in Europe were estimated based on data collected from 36 European countries. For X-ray procedures in EU and EFTA countries (except Liechtenstein) the collective effective dose is 547 500 man Sv, resulting in a mean effective dose of 1.06 mSv per caput. For all European countries included in the survey the collective effective dose is 605 000 man Sv, resulting in a mean effective dose of 1.05 mSv per caput. For nuclear medicine procedures in EU countries and EFTA (except Liechtenstein) countries the collective effective dose is 30 700 man Sv, resulting in a mean effective dose of 0.06 mSv per caput. For all European countries included in the survey the collective effective dose is 31 100 man Sv, resulting in a mean effective dose of 0.05 mSv per caput. (authors)

  14. Personal monitoring and assessment of doses received by radiation workers

    International Nuclear Information System (INIS)

    Swindon, T.N.; Morris, N.D.

    1981-12-01

    The Personal Radiation Monitoring Service operated by the Australian Radiation Laboratory is outlined and the types of monitors used for assessment of doses received by radiation workers are described. The distribution of doses received by radiation workers in different occupational categories is determined. From these distributions, the average doses received have been assessed and the maximum likely additional increase in cancer deaths in Australia as a result of occupational exposure estimated. This increase is shown to be very small. There is, however, a considerable spread of doses received by individuals within occupational groups

  15. A dose-per-pulse monitor for a dual-mode medical accelerator

    International Nuclear Information System (INIS)

    Galbraith, D.M.; Martell, E.S.; Fueurstake, T.; Norrlinger, B.; Schwendener, H.; Rawlinson, J.A.

    1990-01-01

    On a radiotherapy accelerator, the dose monitoring system is the last level of protection between the patient and the extremely high dose rate which all accelerators are capable of producing. The risk of losing this level of protection is substantially reduced if two or more dose monitoring systems are used which are mechanically and electrically independent in design. This paper describes the installation of an independent radiation monitor in a dual-mode, computer-controlled accelerator with a moveable monitor chamber. The added device is fixed in the beam path, is capable of monitoring each beam pulse, and is capable of terminating irradiation within the pulse repetition period if any measured pulse is unacceptably high

  16. Method of estimating patient skin dose from dose displayed on medical X-ray equipment with flat panel detector

    International Nuclear Information System (INIS)

    Fukuda, Atsushi; Koshida, Kichiro; Togashi, Atsuhiko; Matsubara, Kousuke

    2004-01-01

    The International Electrotechnical Commission (IEC) has stipulated that medical X-ray equipment for interventional procedures must display radiation doses such as air kerma in free air at the interventional reference point and dose area product to establish radiation safety for patients (IEC 60601-2-43). However, it is necessary to estimate entrance skin dose for the patient from air kerma for an accurate risk assessment of radiation skin injury. To estimate entrance skin dose from displayed air kerma in free air at the interventional reference point, it is necessary to consider effective energy, the ratio of the mass-energy absorption coefficient for skin and air, and the backscatter factor. In addition, since automatic exposure control is installed in medical X-ray equipment with flat panel detectors, it is necessary to know the characteristics of control to estimate exposure dose. In order to calculate entrance skin dose under various conditions, we investigated clinical parameters such as tube voltage, tube current, pulse width, additional filter, and focal spot size, as functions of patient body size. We also measured the effective energy of X-ray exposure for the patient as a function of clinical parameter settings. We found that the conversion factor from air kerma in free air to entrance skin dose is about 1.4 for protection. (author)

  17. Localization of Gamma-Ray Bursts Using the Fermi Gamma-Ray Burst Monitor

    NARCIS (Netherlands)

    Connaughton, V.; Briggs, M.S.; Goldstein, A.; Meegan, C.A.; Paciesas, W.S.; Preece, R.D.; Wilson-Hodge, C.A.; Gibby, M.H.; Greiner, J.; Gruber, D.; Jenke, P.; Kippen, R.M.; Pelassa, V.; Xiong, S.; Yu, H-F.; Bhat, P.N.; Burgess, J.M.; Byrne, D.; Fitzpatrick, G.; Foley, S.; Giles, M.M.; Guiriec, S.; van der Horst, A.J.; von Kienlin, A.; McBreen, S.; McGlynn, S.; Tierney, D.; Zhang, B..B.

    2015-01-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the

  18. Required doses for projection methods in X-ray diagnosis

    International Nuclear Information System (INIS)

    Hagemann, G.

    1992-01-01

    The ideal dose requirement has been stated by Cohen et al. (1981) by a formula basing on parallel beam, maximum quantum yield and Bucky grid effect depending on the signal to noise ratio and object contrast. This was checked by means of contrast detail diagrams measured at the hole phantom, and was additionally compared with measurement results obtained with acrylic glass phantoms. The optimal dose requirement is obtained by the maximum technically possible approach to the ideal requirement level. Examples are given, besides for x-ray equipment with Gd 2 O 2 S screen film systems for grid screen mammography, and new thoracic examination systems for mass screenings. Finally, a few values concerning the dose requirement or the analogous time required for fluorscent screening in angiography and interventional radiology, are stated, as well as for dentistry and paediatric x-ray diagnostics. (orig./HP) [de

  19. Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

    Energy Technology Data Exchange (ETDEWEB)

    Schandorf, C.; Tetteh, G.K

    1998-07-01

    The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

  20. Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

    International Nuclear Information System (INIS)

    Schandorf, C.; Tetteh, G.K.

    1998-01-01

    The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

  1. The influence of x-ray energy on lung dose uniformity in total-body irradiation

    International Nuclear Information System (INIS)

    Ekstrand, Kenneth; Greven, Kathryn; Wu Qingrong

    1997-01-01

    Purpose: In this study we examine the influence of x-ray energy on the uniformity of the dose within the lung in total-body irradiation treatments in which partial transmission blocks are used to control the lung dose. Methods and Materials: A solid water phantom with a cork insert to simulate a lung was irradiated by x-rays with energies of either 6, 10, or 18 MV. The source to phantom distance was 3.9 meters. The cork insert was either 10 cm wide or 6 cm wide. Partial transmission blocks with transmission factors of 50% were placed anterior to the cork insert. The blocks were either 8 or 4 cm in width. Kodak XV-2 film was placed in the midline of the phantom to record the dose. Midplane dose profiles were measured with a densitometer. Results: For the 10 cm wide cork insert the uniformity of the dose over 80% of the block width varied from 6.6% for the 6 MV x-rays to 12.2% for the 18 MV x-rays. For the 6 cm wide cork insert the uniformity was comparable for all three x-ray energies, but for 18 MV the central dose increased by 9.4% compared to the 10 cm wide insert. Conclusion: Many factors must be considered in optimizing the dose for total-body irradiation. This study suggests that for AP/PA techniques lung dose uniformity is superior with 6 MV irradiation. The blanket recommendation that the highest x-ray energy be used in TBI is not valid for all situations

  2. PATIENT RADIATION DOSE FROM CHEST X-RAY EXAMINATIONS IN THE WEST BANK-PALESTINE.

    Science.gov (United States)

    Lahham, Adnan; Issa, Ahlam; ALMasri, Hussein

    2018-02-01

    Radiation doses to patients resulting from chest X-ray examinations were evaluated in four medical centers in the West Bank and East Jerusalem-Palestine. Absorbed organ and effective doses were calculated for a total of 428 adult male and female patients by using commercially available Monte Carlo based softwares; CALDOSE-X5 and PCXMC-2.0, and hermaphrodite mathematical adult phantoms. Patients were selected randomly from medical records in the time period from November 2014 to February 2015. A database of surveyed patients and exposure factors has been established and includes: patient's height, weight, age, gender, X-ray tube voltage, electric current (mAs), examination projection (anterior posterior (AP), posterior anterior (PA), lateral), X-ray tube filtration thickness in each X-ray equipment, anode angle, focus to skin distance and X-ray beam size. The average absorbed doses in the whole body from different projections were: 0.06, 0.07 and 0.11 mGy from AP, PA and lateral projections, respectively. The average effective dose for all surveyed patients was 0.14 mSv for all chest X-ray examinations and projections in the four investigated medical centers. The effect of projection geometry was also investigated. The average effective doses for AP, PA and lateral projections were 0.14, 0.07 and 0.22 mSv, respectively. The collective effective dose estimated for the exposed population was ~60 man-mSv. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Preliminary characterization of the passive neutron dose equivalent monitor with TLDs

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Norio; Kanai, Katsuta; Momose, Takumaro; Hayashi, Naomi [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Chen Erhu [Beijing Institute of Nuclear Engineering, Beijing (China)

    2001-02-01

    The passive neutron dose equivalent monitor with TLDs is composed of a cubic polyethylene moderator and TLDs at the center of moderator. This monitor was originally designed for measurements of neutron doses over long-term period of time around the nuclear facilities. In this study, the energy response of this monitor was calculated by Monte Carlo methods and experimentally obtained under {sup 241}Am-Be, {sup 252}Cf and moderated {sup 252}Cf neutron irradiation. Additionally, the responses of two types of conventional neutron dose equivalent meters (rem counters) were also investigated as comparison. The authors concluded that this passive neutron monitor with TLDs had a good energy response similar to conventional rem counters and could evaluate neutron doses within 10% of accuracy to the moderated fission spectra. (author)

  4. Late effects of chronic low dose-rate γ-rays irradiation on mice

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Sasagawa, Sumiko; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Otsu, Hiroshi; Sato, Fumiaki

    2002-01-01

    To evaluate late biological effects of chronic low dose-rate radiation, we are conducting two experiments. Experiment 1 - Late effects of chronic low dose-rate g-rays irradiation on SPF mice, using life-span and pathological changes as parameters. Continuous irradiation with g-rays for 400 days was performed using 137 Cs γ-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8,000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until they died a natural death. As of 2002 March 31, 3,999 of the total 4,000 mice have died. Preliminary analyses of data show that 20 mGy/day suggested a shortened life span in both sexes. Partial results show that the most common lethal neoplasms in the pooled data of non-irradiated control and irradiated male mice, in order of frequency, were neoplasms of the lymphohematopoietic system, liver, and lung. In female mice, neoplasms of the lymphohematopoietic system, soft tissue, and endocrine system were common. Experiment 2 - Effects on the progeny of chronic low dose-rate g-ray irradiated SPF mice: pilot study, was started in 1999 and is currently in progress. (author)

  5. Gamma-ray mutagenic effect on adzuki bean and the optimum dose

    International Nuclear Information System (INIS)

    Shen Huifang; Li Guozhu

    2012-01-01

    Dry seeds of three kinds of adzuki beans (Jinhong1, Jihong9218, and Jingnong6) were irradiated by 60 Co γ-rays to 100, 200, 300, 400, 500 and 600 Gy. The radiation effects on seedlings were analyzed to estimate the optimum dose, which was 400 to 600 Gy, based on the average half lethal dose (LD 50 ) of 473.3 Gy for the three kinds of adzuki beans. The M 1 γ-ray mutagenic effects were studied by farming the three kinds of adzuki beans irradiated to 350, 500 and 650 Gy. It was found that the beans treated with higher doses had obvious inhibition on germination rate, seedling development, with significant or very significant difference compared with the CK. There was significantly negative correlation between seedling emergences, seedling height and doses. Irradiation affected mature plants by reducing plant height, decreasing nodes number of main stem, pods number per plant, seeds per pod and shortening pod length with significant. The order of radio-sensitivity to γ-rays was as follows: Jinhong1, Jihong9218, and Jingnong6. (authors)

  6. Radiation doses from some common paediatric X-ray examinations in Sudan

    International Nuclear Information System (INIS)

    Suliman, I.I.; Elshiekh, E.H.A.

    2008-01-01

    Radiation doses to patients from some common paediatric X-ray examinations were studied in three hospitals in Khartoum state (Sudan)). Entrance surface dose (ESD) was determined from exposure settings using DosCal software. Totally, 459 patients were included in this study. Mean ESDs obtained from anteroposterior projection for chest, skull, abdomen and pelvis for neonates falls in the range of 52-100, 115-169, 145-183, 204-242 μGy, respectively. For a 1-y-old infant, mean ESD range was 80-114, 153-202, 204-209, 181-264 μGy, respectively. Some doses for neonates and infants were exceeding the reference doses by >20%. The results highlighted that a good technique has to adhere to guidelines necessarily. As demonstrated elsewhere, patients' doses were high in departments using single-phase generators compared with those using constant potential. The results presented will serve as a baseline data needed for deriving reference doses for paediatric X-ray examinations in Sudan. (authors)

  7. Low-dose phase contrast tomography with conventional x-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, C. K., E-mail: charlotte.hagen.10@ucl.ac.uk; Endrizzi, M.; Diemoz, P. C.; Olivo, A. [Department of Medical Physics and Bioengineering, University College London, Malet Place, Gower Street, London WC1E 6BT (United Kingdom); Munro, P. R. T. [Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia and Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2014-07-15

    Purpose: The edge illumination (EI) x-ray phase contrast imaging (XPCi) method has been recently further developed to perform tomographic and, thus, volumetric imaging. In this paper, the first tomographic EI XPCi images acquired with a conventional x-ray source at dose levels below that used for preclinical small animal imaging are presented. Methods: Two test objects, a biological sample and a custom-built phantom, were imaged with a laboratory-based EI XPCi setup in tomography mode. Tomographic maps that show the phase shift and attenuating properties of the object were reconstructed, and analyzed in terms of signal-to-noise ratio and quantitative accuracy. Dose measurements using thermoluminescence devices were performed. Results: The obtained images demonstrate that phase based imaging methods can provide superior results compared to attenuation based modalities for weakly attenuating samples also in 3D. Moreover, and, most importantly, they demonstrate the feasibility of low-dose imaging. In addition, the experimental results can be considered quantitative within the constraints imposed by polychromaticity. Conclusions: The results, together with the method's dose efficiency and compatibility with conventional x-ray sources, indicate that tomographic EI XPCi can become an important tool for the routine imaging of biomedical samples.

  8. Monitoring requirements for assessment of internal dose

    International Nuclear Information System (INIS)

    Eckerman, K.F.

    1985-01-01

    Data obtained by routine personnel monitoring is usually not a sufficient basis for estimation of dose. Collected data must be interpreted carefully and supplemented with appropriate information before reasonably accurate estimates of dose (i.e., accurate enough to indicate whether or nor personnel are exposed in excess of recommended limits) can be developed. When the exposure is of sufficient magnitude that a rather precise estimate of dose is needed, the health physicist will bring to bear on the problem other, more refined, methods of dosimetry. These might include a reconstruction of the incident and, for internal emitters, an extensive series of in vivo measurements or analyses of excreta. Thus, cases of special significance must often be evaluated using techniques and resources beyond those routinely employed. This is not a criticism of most routine monitoring programs. These programs are usually carefully designed in a manner commensurate with the degree of exposure routinely encountered and the requirement of a practical program of radiation protection. 10 refs

  9. TL detectors for gamma ray dose measurements in criticality accidents

    International Nuclear Information System (INIS)

    Miljanic, S.; Zorko, B.; Gregori, B.; Knezevic, Z.

    2007-01-01

    Determination of gamma ray dose in mixed neutron + gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Boskovic Inst. (RBI), Croatia, Jozef Stefan Inst. (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7 LiF (TLD-700), CaF 2 :Mn and Al2 O3 :Mg,Y - all from RBI; CaF 2 :Mn from JSI and 7 LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (authors)

  10. TL detectors for gamma ray dose measurements in criticality accidents.

    Science.gov (United States)

    Miljanić, Saveta; Zorko, Benjamin; Gregori, Beatriz; Knezević, Zeljka

    2007-01-01

    Determination of gamma ray dose in mixed neutron+gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Bosković Institute (RBI), Croatia, JoZef Stefan Institute (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7LiF (TLD-700), CaF2:Mn and Al2O3:Mg,Y-all from RBI; CaF2:Mn from JSI and 7LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed.

  11. The development of wireless radiation dose monitoring using smart phone

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Woo; Jeong, Gyo Seong; Lee, Yun Jong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kim, Chong Yeal [Chonbuk National University, Jeonju (Korea, Republic of); Lim, Chai Wan [REMTECH, Seoul (Korea, Republic of)

    2016-11-15

    Radiation workers at a nuclear facility or radiation working area should hold personal dosimeters. some types of dosimeters have functions to generate audible or visible alarms to radiation workers. However, such devices used in radiation fields these days have no functions to communicate with other equipment or the responsible personnel. our project aims at the development of a remote wireless radiation dose monitoring system that can be utilized to monitor the radiation dose for radiation workers and to notify the radiation protection manager of the dose information in real time. We use a commercial survey meter for personal radiation measurement and a smart phone for a mobile wireless communication tool and a Beacon for position detection of radiation workers using Blue tooth communication. In this report, the developed wireless dose monitoring of cellular phone is introduced.

  12. Organ doses for foetuses, babies, children and adults from environmental gamma rays

    International Nuclear Information System (INIS)

    Petoussi, N.; Jacob, P.; Zankl, M.; Saito, K.

    1991-01-01

    Organ doses for babies, children and adults and doses to foetuses from environmental gamma rays were calculated using Monte Carlo codes. Firstly, gamma ray fields in the air-over-ground geometry were simulated, neglecting the disturbances of the radiation field by the human body. The exposure modes considered were semi-infinite homogeneous volume sources in the air, infinite plane sources at a depth of 0.5 g.cm -2 in the ground and homogeneous volume sources of natural radionuclides in the ground. The results of the simulation of the gamma ray transport in the air-over-ground geometry were used as sources irradiating the anthropomorphic phantoms: an 8 week old baby, a seven year old child and two 'reference' adult phantoms of a male and a female. The dose to foetuses were estimated from the dose to the uterus of the adult female. Dose conversion factors normalised to source intensity and air kerma were calculated for monoenergetic sources (15 keV to 10 MeV) and natural and artificial radionuclides. (author)

  13. X-ray absorbed doses evaluation on patients under radiological studies

    International Nuclear Information System (INIS)

    Medeiros, Regina Bitelli; Daros, Kellen A.C.

    1996-01-01

    The skin absorbed doses were evaluated on patient submitted to the following x-ray exams : chest, facial sinus, lumbar spine. Thermoluminescent dosimetry was used and a variety of irradiation techniques performed. The results shown considerable differences on the absorbed dose for the various alternative technical conditions

  14. Collective radiation dose from diagnostic x-ray examination in nine ...

    African Journals Online (AJOL)

    Background: Medical x-ray exposures have the largest man made source of population exposure to ionizing radiation in different countries. Recent developments in medical imaging have led to rapid increases in a number of high dose xray examinations performed with significant consequences for individual patient doses ...

  15. Calculation of organ doses in X-ray examinations of premature babies

    International Nuclear Information System (INIS)

    Smans, K.

    2009-01-01

    As ionizing radiation has enabled great progress in the diagnostic and therapeutic aspects of medicine, its use is in most cases easily justifiable. General radiation protection principles require additionally that radiation doses of the patients should be as low as reasonably achievable within the medical purposes. In Europe this is stipulated in the directive 97/43/Euratom. This directive also requires that special attention should be given to the patient doses in pediatric examinations, of which premature babies constitute an important sub-group. All babies born before 37 weeks of gestation are defined as being prematurely born. Newborn and prematurely born babies are particularly sensitive to the detrimental effects of X-rays. Risk of cancer induction is believed to be 2 to 3 times higher than that of the average population and 6 to 9 times higher than the risk from an exposure at 60 years of age, for equal dose. A premature born child may be exposed to a large number of diagnostic X-ray examinations. Several of these infants may have underdeveloped lungs, which may lead directly to the respiratory distress syndrome (RDS) or to (lethal) lunghypoplasia/hypertension. Diagnosis and follow-up of the respiratory distress syndrome by means of chest radiography is justified. Risks associated with X-ray examinations are low compared to the other medical risks that these patients face, but even in this case the radiation dose should be kept as low as possible. Knowledge of the radiation dose is a first step in the optimization process. A recent study on 255 premature children in the University Hospital of Gasthuisberg found that they undergo 10 X-ray examinations, on the average. In this sample, the maximum was 78 X-ray examinations

  16. Microwave-gamma ray water in crude monitor

    International Nuclear Information System (INIS)

    Paap, H.J.

    1984-01-01

    A microwave-gamma ray water-in-crude monitoring system measures the percent quantity of fresh water or salt water in crude oil flowing in a pipe line. The system includes a measuring cell arranged with the pipe line so that the crude oil flows through the measuring cell. A microwave transmitter subsystem and a gamma ray source are arranged with the measuring cell so that microwave energy and gamma rays are transmitted through the measuring cell. A microwave receiving subsystem and a gamma ray detector provide signals corresponding to received microwave energy and to the received gamma rays, respectively. Apparatus connected to the microwave receiver and to the gamma ray detector provides an indication of the percentage of water in the crude oil

  17. A real time dose monitoring and dose reconstruction tool for patient specific VMAT QA and delivery

    International Nuclear Information System (INIS)

    Tyagi, Neelam; Yang Kai; Gersten, David; Yan Di

    2012-01-01

    Purpose: To develop a real time dose monitoring and dose reconstruction tool to identify and quantify sources of errors during patient specific volumetric modulated arc therapy (VMAT) delivery and quality assurance. Methods: The authors develop a VMAT delivery monitor tool called linac data monitor that connects to the linac in clinical mode and records, displays, and compares real time machine parameters with the planned parameters. A new measure, called integral error, keeps a running total of leaf overshoot and undershoot errors in each leaf pair, multiplied by leaf width, and the amount of time during which the error exists in monitor unit delivery. Another tool reconstructs Pinnacle 3 ™ format delivered plan based on the saved machine logfile and recalculates actual delivered dose in patient anatomy. Delivery characteristics of various standard fractionation and stereotactic body radiation therapy (SBRT) VMAT plans delivered on Elekta Axesse and Synergy linacs were quantified. Results: The MLC and gantry errors for all the treatment sites were 0.00 ± 0.59 mm and 0.05 ± 0.31°, indicating a good MLC gain calibration. Standard fractionation plans had a larger gantry error than SBRT plans due to frequent dose rate changes. On average, the MLC errors were negligible but larger errors of up to 6 mm and 2.5° were seen when dose rate varied frequently. Large gantry errors occurred during the acceleration and deceleration process, and correlated well with MLC errors (r= 0.858, p= 0.0004). PTV mean, minimum, and maximum dose discrepancies were 0.87 ± 0.21%, 0.99 ± 0.59%, and 1.18 ± 0.52%, respectively. The organs at risk (OAR) doses were within 2.5%, except some OARs that showed up to 5.6% discrepancy in maximum dose. Real time displayed normalized total positive integral error (normalized to the total monitor units) correlated linearly with MLC (r= 0.9279, p < 0.001) and gantry errors (r= 0.742, p= 0.005). There is a strong correlation between total integral

  18. An interactive RADIANCE toolkit for customizable CT dose monitoring and reporting.

    Science.gov (United States)

    Cook, Tessa S; Sundaram, Anand; Boonn, William W; Kim, Woojin

    2013-08-01

    The need for tools to monitor imaging-related radiation has grown dramatically in recent years. RADIANCE, a freely available open-source dose-monitoring tool, was developed in response to the need for an informatics solution in this realm. A number of open-source as well as commercial solutions have since been developed to enable radiology practices to monitor radiation dose parameters for modalities ranging from computed tomography to radiography to fluoroscopy. However, it is not sufficient to simply collect this data; it is equally important to be able to review it in the appropriate context. Most of the currently available dose-monitoring solutions have some type of reporting capability, such as a real-time dashboard or a static report. Previous versions of RADIANCE have included a real-time dashboard with pre-set screens that plot effective dose estimates according to different criteria, as well as monthly scorecards to summarize dose estimates for individuals within a radiology practice. In this work, we present the RADIANCE toolkit, a customizable reporting solution that allows users to generate reports of interest to them, summarizing a variety of metrics that can be grouped according to useful parameters. The output of the toolkit can be used for real-time dose monitoring or scheduled reporting, such as to a quality assurance committee. Making dose parameter data more accessible and more meaningful to the user promotes dose reduction efforts such as regular protocol review and optimization, and ultimately improves patient care by decreasing unnecessary radiation exposure.

  19. TH-E-209-02: Dose Monitoring and Protocol Optimization: The Pediatric Perspective

    International Nuclear Information System (INIS)

    MacDougall, R.

    2016-01-01

    Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.

  20. TH-E-209-02: Dose Monitoring and Protocol Optimization: The Pediatric Perspective

    Energy Technology Data Exchange (ETDEWEB)

    MacDougall, R. [Boston Children’s Hospital (United States)

    2016-06-15

    Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.

  1. Effective dose due to environmental γ-ray for the people of Akita prefecture

    International Nuclear Information System (INIS)

    Yamashita, Junsuke; Watarai, Jiro; Hisamatsu, Shun'ichi

    2001-01-01

    Environmental γ-ray doses were measured in Akita prefecture by a NaI(Tl) scintillation surveymeter. The numbers of measurement site were 207 on pavement, 45 on unpaved ground, nine in concrete buildings and nine in wooden houses. The results of measurements, which were subtracted for background (cosmic ray and self-irradiation of the surveymeter), were 31 nSv/h (effective dose rate) on pavement, 27 nSv/h on unpaved ground, 65 nSv/h in the concrete buildings and 34 nSv/h in the wooden houses. The effective dose rate due to environmental γ-ray for the people of Akita prefecture was estimated taking into account of seasonal change of the dose rate at one site and occupancy factor in the prefecture. The outdoor and indoor dose rates were estimated to be 0.03 mSv/y and 0.33 mSv/y, respectively. (author)

  2. TL detectors for gamma-ray dose measurements in critically accidents

    International Nuclear Information System (INIS)

    Miljanic, S.; Knezevic, Z.; Zorko, B.; Gregori, B.

    2005-01-01

    Full text: Determination of gamma-ray dose in mixed neutron + gamma-ray fields is still a challenging task. Dosemeters used for gamma-ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e. on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosimeter responses to gamma-rays. To reduce all these influences, design of dosemeter holders is of special importance. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma-ray dose determination in mixed fields were examined. Dosemeters were from three different institutions: Ruder Boscovic Institute (RBI), Croatia, Jozef Stefan Institute (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. At that exercise three accidental scenarios were reproduced: bare reactor, free evolution; lead shielded reactor, steady state; and lead shielded reactor, free evolution. In each irradiation dosemeters were exposed placed on the front of phantom and 'free-in-air'. Also, dosemeters were irradiated in a pure gamma ray field of 60 Co source. Following types of TLDs were used: 7 LiF (TLD-700), CaF 2 :Mn and AI 2 O 3 :Mg,Y - all from RBI; CaF 2 :Mn from JSI and 7 LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the mean participants' values. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (author)

  3. 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

  4. Evaluation of patient dose in imaging using a cone-beam CT dosimetry by X-ray films for radiotherapeutic dose

    International Nuclear Information System (INIS)

    Yoshida, Yuri; Morita, Yasuhiko; Honda, Eiichi; Tomotake, Yoritoki; Ichikawa, Tetsuo

    2008-01-01

    A limited cone-beam X-ray CT (3DX multi-image micro CT; 3DX-FPD) is widely used in dentistry because it provides a lower cost, smaller size, and higher spatial resolution than a CT for medicine. Our recent research suggested that the patient dose of 3DX-FPD was less than 7/10 of that of CT, and it was several to 10 times more than that of dental or panoramic radiography. The purpose of this study was to evaluate the spatial dose distribution from 3DX-FPD and to estimate the influence of dose by positioning of the region of interest. Dosimetry of the organs and the tissues was performed using an anthropomorphic Alderson Rando phantom and X-ray films for measurement of radiotherapeutic dose. Measurements of dose distribution were performed using a cylinder-type tank of water made of acrylic resin imitating the head and X-ray films. The results are summarized as follows: The dose was higher as the ratio of the air region included in the region of interest increased. The dose distribution was not homogeneous and the dose was highest in the skin region. The dose was higher for several seconds after the beginning of exposure. It was concluded that patient positioning, as well as exposure conditions including the size of the exposure field and tube current, could greatly influence the patient dose in 3DX-FPD. In addition, it is necessary to consider the influence of image quality for the treatment of dental implants. (author)

  5. 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

  6. Assessing the dose values received by patients during conventional radiography X-ray examinations and the technical condition of the equipment used for this purpose.

    Science.gov (United States)

    Bekas, Marcin; Pachocki, Krzysztof A; Waśniewska, Elżbieta; Bogucka, Dagmara; Magiera, Andrzej

    2014-01-01

    X-ray examination is associated with patient exposure to ionizing radiation. Dose values depend on the type of medical procedure used, the X-ray unit technical condition and exposure conditions selected. The aim of this study was to determine the dose value received by patients during certain conventional radiography X-ray examinations and to assess the technical condition of medical equipment used for this purpose. The study covered the total number of 118 conventional diagnostic X-ray units located in the Masovian Voivodeship. The methodology used to assess the conventional diagnostic X-ray unit technical condition and the measurement of the radiation dose rate received by patients are based on test procedures developed by the Department of Radiation Protection and Radiobiology of the National Institute of Public Health - National Institute of Hygiene (Warszawa, Poland) accredited for compliance with PN-EN 17025 standard by the Polish Centre for Accreditation. It was found that 84.7% of X-ray units fully meet the criteria set out in the Polish legislation regarding the safe use of ionizing radiation in medicine, while 15.3% of the units do not meet some of them. The broadest dose value range was recorded for adult patients. Particularly, during lateral (LATl) lumbar spine radiography the recorded entrance surface dose (ESD) values ranged from 283.5 to 7827 µGy (mean: 2183.3 µGy). It is absolutely necessary to constantly monitor the technical condition of all X-ray units, because it affects population exposure to ionizing radiation. Furthermore, it is essential to raise radiographers' awareness of the effects that ionizing radiation exposure can have on the human body.

  7. Development of personal dose monitoring system using wireless data transmission device

    International Nuclear Information System (INIS)

    Inui, Daisuke; Nakashima, Sadao

    2008-01-01

    Radiation workers working in radiation controlled area in nuclear power plants etc., are required to carry a dosimeters by regulation law. The workers are controlled daily on personal exposure dose by reading out the exposure dose information of the dosimeters with an area access control gate installed at the entrance of the radiation controlled area. This type of personal dose monitoring system has a problem that each worker can get his personal dose data only at the entrance of the radiation controlled area several times a day. We developed a system to get the real-time acquisition of personal dose data especially for workers working in a high dose area. This system is generally composed of a dosimeter with a wireless attachment, relay station, and monitor. Some relay stations set in main work places in the radiation controlled area can collect real-time personal dose data of each dosimeter carried by workers at the work place with the relay stations, and transmit it to the monitor to get personal dose data of individual workers. A wireless communication system between dosimeters and relay stations is applied to collect efficiently all personal dose data in the work place. (author)

  8. Determination of entrance skin dose from diagnostic X-ray of human ...

    African Journals Online (AJOL)

    patient during x-ray examination in Federal Medical Centre, Keffi in Nasarawa state, Nigeria. Entrance skin doses (ESDs) for a common type of x-ray procedures, namely chest AP/PA (anterior/posterior) were measured. A total of 200 data were collected from patients who were exposed to diagnostic X-ray during their routine ...

  9. Evaluation of dose to tooth enamel from medical diagnostic X-ray examinations at Mayak PA

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, A., E-mail: wieser@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Vasilenko, E. [Mayak Production Association, 456780 Ozyorsk (Russian Federation); Zankl, M.; Greiter, M.; Ulanovsky, A. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Sabayev, A.; Knyazev, V.; Zahrov, P. [Mayak Production Association, 456780 Ozyorsk (Russian Federation)

    2011-09-15

    The nuclear workers of the Mayak Production Association had regular check-ups including medical diagnostic X-ray examinations since start of the production lines in 1948. Doses from diagnostic examinations need to be considered in reconstruction of occupational doses of the workers with electron paramagnetic resonance (EPR) of tooth enamel. The numbers and types of examinations of an individual worker can be assessed from the Mayak PA archives but no information was available on doses delivered to teeth by a single specific examination. Of the twenty one applied examination procedures only three affected the teeth, these being X-ray examinations of teeth, skull and cervical spine. For these three kinds of examinations operational procedures and operating modes of X-ray units were compiled from the archive and photon spectra were obtained from a catalog of spectral data for diagnostic X-rays. Entrance doses in air kerma were calculated using the fluence of photon spectra and absorbed dose in tooth enamel for various tooth positions and exposure geometry was then calculated using dose conversion coefficients obtained from Monte Carlo simulations. Doses were calculated for examinations in 1948-2000. Except for examination of the skull, absorbed doses in enamel of incisors were found to be about twice as large as in enamel of molars. In the period before 1970 the largest mean absorbed doses in tooth enamel were due to X-ray examination of teeth, with 64 mGy and 34 mGy calculated for incisors and molars, respectively. In the same period the lowest mean doses were due to X-ray examination of the skull, with 11 mGy and 12 mGy calculated for incisors and molars, respectively. In the period from 1970 to 2000, largest mean doses in enamel were due to X-ray examination of cervical spine, with 23 mGy and 12 mGy calculated for incisors and molars, respectively.

  10. New model for assessing dose and dose rate sensitivity of Gamma ray radiation loss in polarization maintaining optical fibers

    International Nuclear Information System (INIS)

    Zhang Hongchen; Liu Hai; Qiao Wenqiang; Xue Huijie; He Shiyu

    2012-01-01

    Highlights: ► Building a new phenomenological theory model to investigate the relation about the irradiation induced loss with irradiation dose and dose rate. ► The Gamma ray irradiation induced loss of the “Capsule” type and “Panda” type polarization maintaining optical fibers at 1310 nm wavelength are investigated. ► The anti irradiation performance of the “Panda” type polarization maintaining optical fiber is better than that of the “Capsule” type polarization maintaining optical fiber, the reason is that the stress region doped by GeO 2 . - Abstract: The Gamma ray irradiation induced loss of the “Capsule” type and “Panda” type polarization maintaining optical fibers at 1310 nm wavelength are investigated. A phenomenological theory model is introduced and the influence of irradiation dose and dose rate on the irradiation induced loss is discussed. The phenomenological theoretical results are consistent with the experimental results of the irradiation induced loss for the two types of polarization maintaining optical fibers. The anti irradiation performance of the “Panda” type polarization maintaining optical fiber is better than that of the “Capsule” type polarization maintaining optical fiber, the reason is that the stress region dope with GeO 2 . Meanwhile, both of the polarization maintaining optical fiber irradiation induced loss increase with increasing the irradiation dose. In the case of same dose, the high dose rate Gamma ray irradiation induced optical fiber losses are higher than that of the low dose rate.

  11. Division delay after low x-ray doses and treatment with cyclohexionide

    International Nuclear Information System (INIS)

    Schneiderman, M.H.; Braby, L.A.; Roesch, W.C.

    1977-01-01

    Radiation-induced division delay of Chinese hamster ovary cells located in G 2 , and in G 2 between the cycloheximide and x-ray transition points, was measured by the mitotic cell selection technique. The mitotic yield (number of mitotic cells after treatment expressed as a fraction of the control) decreased with increasing radiation dose (4.5 to 34 rad). However, either because some cells were not delayed or because delayed cells recovered rapidly, the mitotic yield did not fall to zero. When cycloheximide was combined with radiation to prevent repair of the radiation damage, only cells which were past the cycloheximide transition point and not delayed by the radiation were selected. The location of the transition points determined from the combined drug plus low-dose radiation (4.5 to 34 rad) experiments indicate a dose-dependent relationship, with more cells delayed as the dose was increased. In addition, the transition point for cells treated with cycloheximide plus 150 rad of x rays was closer to division than the 150 rad of x rays alone. These results are discussed in light of a recent model for radiation-induced division delay proposed by Dewey and Highfield

  12. Variation in Depth Dose Data between Open and Wedge Fields for 6 MV X-Rays

    International Nuclear Information System (INIS)

    U, Hong; Ryu, M. S. Samuel; Park, In Kyu

    1989-01-01

    Central axis depth dose data for 6 MV X-rays, including tissue maximum ratios, were measured for wedge fields according to Tatcher equation. In wedge fields, the differences in magnitude which increased with depth, field size, and wedge thickness increased when compared with the corresponding open field data. However, phantom scatter correction factors for wedge fields differed less that 1% from the corresponding open field factors. The differences in central axis percent depth dose between two types of fields indicated beam hardening by the wedge filter. The deviation of percent depth doses and scatter correction factors between the effective wedge field and the nominal wedge field at same angle was negligible. The differences were less than 3.26% between the nominal or effective wedge fields and the open fields for percent depth doses to the depth 7cm in 6cm x 6cm field. For larger (10cm x 10cm) field size, however, the deviation of percent depth doses between the nominal or effective wedge fields and the open fields were greater-dosimetric errors were 3.56% at depth 7cm and nearly 5.30% at 12cm. We suggest that the percent depth doses of individual wedge and wedge transmission factors should be considered for the dose calculation or monitor setting in the treatment of deep seated tumor

  13. Evaluation of skyshine dose due to gamma-rays from a cobalt-60 irradiation facility

    International Nuclear Information System (INIS)

    Kanazawa, Tamotsu; Okamoto, Shinichi; Ohnishi, Tokuhiro; Tsujii, Yukio

    1991-01-01

    We attempted to evaluate skyshine dose due to gamma-rays from a cobalt-60 irradiation facility. As the first step, the results of measurements and calculations were compared of the skyshine dose due to gamma-rays from the cobalt-60 source of 1.45 PBq set in the No.4 irradiation room of our laboratory. Distances of measuring points from the cobalt source were in the range from 17 m to about 100 m in the site of our office. Calculation was carried out with simplified single scattering method. The calculated values of the skyshine dose were higher than the measured values. For more precise evaluation of the skyshine dose, the following factors are to be considered; the dose rate distribution on the roof above the source and the attenuation of gamma-rays by air. (author)

  14. Neutron and gamma-ray dose-rates from the Little Boy replica

    International Nuclear Information System (INIS)

    Plassmann, E.A.; Pederson, R.A.

    1984-01-01

    We report dose-rate information obtained at many locations in the near vicinity of, and at distances out to 0.64 km from, the Little Boy replica while it was operated as a critical assembly. The measurements were made with modified conventional dosimetry instruments that used an Anderson-Braun detector for neutrons and a Geiger-Mueller tube for gamma rays with suitable electronic modules to count particle-induced pulses. Thermoluminescent dosimetry methods provide corroborative data. Our analysis gives estimates of both neutron and gamma-ray relaxation lengths in air for comparison with earlier calculations. We also show the neutron-to-gamma-ray dose ratio as a function of distance from the replica. Current experiments and further data analysis will refine these results. 7 references, 8 figures

  15. Personnel dose equivalent monitoring at SLAC using lithium-fluoride TLD's [thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Jenkins, T.M.; Busick, D.D.

    1987-03-01

    TLD's replaced film badges in the early 1970's for all dose equivalent monitoring, both neutron and photon, and for all locations at SLAC. The photon TLD's, composed of Li-7 loaded teflon discs, are calibrated using conventional gamma-ray sources; i.e., Co-60, Cs-137, etc. For these TLD's a nominal value of 1 nC/mrem is used, and is independent of source energy for 100 keV to 3 MeV. Since measured dose equivalents at SLAC are only a small fraction of the allowable levels, it was not deemed necessary to develop neutron dosimeters which would measure dose equivalent accurately for all possible neutron spectra. Today, wallet TLD's, composed of pairs of Li-7 and Li-6 discs, are used, with the Li-6 measuring only thermal neutrons; i.e., they aren't moderated in any way to make them sensitive to neutrons with energies greater than thermal. The assumption is made that there is a correlation between thermal neutron fluences and fast neutron fluences around the research area where almost all neutron doses (exclusive of sealed sources) are received. The calibration factor for these Li-6 TLD's is 1 nC/mrem of fast neutrons. The method of determining the validity of this calibration is the subject of this note. 4 refs., 9 figs., 1 tab

  16. Effect of large dose gamma-ray irradiation on polyimide

    International Nuclear Information System (INIS)

    Morita, Yohsuke; Watanabe, Kiyoshi; Yagyu, Hideki.

    1988-01-01

    In the radiation environment of atomic energy, space and so on, with the heightening of the performance of equipment, the organic materials having the radiation resistance up to several hundreds MGy have been demanded. Polyimide is one of a small number of the polymers which are considered to be applicable to such environment. However, actually the characteristics as the insulator for such large dose radiation environment have not been sufficiently verified. In this study, the gamma-ray of as large dose as 100 MGy was irradiated on the polyimides having different chemical structure in the air and in nitrogen, and the change of their mechanical and electrical characteristics was elucidated, at the same time, the structural change was examined. The four kinds of polyimides used for the experiment were three kinds of thermosetting type and thermoplastic polyether imide. Co-60 gamma-ray was irradiated at the dose rate of 17 kGy/h at room temperature. The tensile properties, volume resistivity, dielectric tangent, gel fraction, glass transition temperature and IR spectra were examined. In the air, the characteristics lowered by large dose irradiation due to the severance of main chains. In nitrogen, the deterioration was extremely slight, and cross-linking occurred. (K.I.)

  17. Gamma ray doses proceeding from natural occurring radionuclides in closed environments

    International Nuclear Information System (INIS)

    Aguiar, Vitor Angelo P. de; Medina, Nilberto H.; Silveira, Marcilei A. Guazzelli da; Moreira, Ramon H.

    2009-01-01

    In this work we report on the application of gamma-ray spectrometry in the study of the effective dose coming from terrestrial natural elements present in building materials such as sand, cement, lime (CaO) and milled granitic stones. The major contribution to annual gamma-ray radiation effective dose is due to the natural occurring radionuclides 40 K, 232 Th and 238 U. Two spectrometry systems were employed to measure the gamma radiation: one with a 60% efficient GeHP detector and the second one with a 2''x2'' NaI(Tl) scintillator. The estimated effective dose coming from the three reference rooms assumed is 0.63 mSv/yr, proceeding from terrestrial natural elements. The principal gamma radiation sources are cement, sand and bricks. (author)

  18. Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari-Dizaji, M.; Sharafi, A. A.; Larijani, B.; Mokhlesian, N.; Hasanzadeh, H. [Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2008-04-15

    Objective : The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods : An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Result : There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 {mu}Gy and 1.81 Gy, respectively. Also, the scan center dose in the women was 5.70 Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion : We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry.

  19. Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

    International Nuclear Information System (INIS)

    Mokhtari-Dizaji, M.; Sharafi, A. A.; Larijani, B.; Mokhlesian, N.; Hasanzadeh, H.

    2008-01-01

    Objective : The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods : An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Result : There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 μGy and 1.81 Gy, respectively. Also, the scan center dose in the women was 5.70 Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion : We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry

  20. Radiation doses to patients from x-ray examinations - development from 2005 to 2008

    International Nuclear Information System (INIS)

    Leitz, Wolfram; Almen, Anja

    2010-04-01

    Data has been compiled and analyzed and compared with the earlier reports. Radiation doses were tested for possible links with various parameters (eg type of x-ray equipment, image recording systems, different technique factors). In conventional x-ray examinations radiation doses were, for equipment with direct digital image receivers, in average 30% lower than for those with photo plates. Mammography doses were, with one exception, the same for all types of equipment and video receivers. The CT-examinations had a small trend for higher doses for new equipment as compared to earlier. Use of exposure automation did not affect radiation doses. Compared with 2006, the doses of conventional surveys decreased by an average of 21%. One third of this dose reduction can be attributed the introduction of direct digital system whose use grew by about 30%. Most of the dose reduction can be attributed to the actions carried out to lower the dose of the reference level. Doses for the CT scan showed only a weak downwards trend. Mammography Doses decreased by an average of just over 10% a large part dependent on increased number of Sectra equipment. The system of diagnostic reference levels have again shown to have positive influence on the radiation level at the x-ray examinations, this is most pronounced for conventional radiography. There is still a large potential for dose reduction, and a measure to achieve this is to reduce the current reference levels. Very few diagnostic Standard doses are higher than the reference level. A reduction of the reference levels corresponding to the third quartile of dose distribution could lead further dose decrease of 10-20%. The corresponding reduction in dose should be done also for the DT and mammograms when lowering the reference level, there are few standard doses higher than the current reference levels

  1. Development of an ionization chamber based high sensitivity detector for the measurement of radiation dose from X-ray whole body scanners

    International Nuclear Information System (INIS)

    Singh, Sunil K.; Tripathi, S.M.; LijiShaiju; Sathian, V.; Kulkarni, M.S.

    2016-01-01

    Using walk through metal detectors and undergoing frisking for personals at airports, seaports, railway stations and other sensitive places no longer meets proper security requirements. Now a days use of plastic explosives, drug trafficking or illegal carriage of dangerous items concealed under cloths or body cavities has increased many folds which in many cases is not possible to detect by conventional methods. One of the systems which are capable to overcome the above mentioned difficulties is the use of X-ray based whole body scanners, either transmission type or backscatter type, depending upon the nature of requirement. While using these whole body scanners the person being scanned possesses a radiation risk whose safety aspects can be monitored by following international standards (recommending certain dose limits). In order to check the compliance of these dose limits, the dose per scan received by the person (from these whole body scanners) needs to be measured. A very high sensitive ionization chamber has been designed and fabricated for measuring these extremely low X- ray fields ( few μR) produced by a scanning X-ray beam over a large area. A methodology has been developed to measure exposure per scan using large volume ionization chambers. This value of exposure was used to calculate whole body dose as per the recommendations of ANSI standard for its compliance

  2. Development of air equivalent gamma dose monitor

    International Nuclear Information System (INIS)

    Alex, Mary; Bhattacharya, Sadhana; Karpagam, R.; Prasad, D.N.; Jakati, R.K.; Mukhopadhyay, P.K.; Patil, R.K.

    2010-01-01

    The paper describes design and development of air equivalent gamma absorbed dose monitor. The monitor has gamma sensitivity of 84 pA/R/h for 60 Co source. The characterization of the monitor has been done to get energy dependence on gamma sensitivity and response to gamma radiation field from 1 R/hr to 5000 R/hr. The gamma sensitivity in the energy range of 0.06 to 1.25MeV relative to 137 Cs nuclide was within 2.5%. The linearity of the monitor response as a function of gamma field from 10 R/h to 3.8 kR/h was within 6%. The monitor has been designed for its application in harsh environment. It has been successfully qualified to meet environmental requirements of shock. (author)

  3. JEM-X: The X-ray monitor aboard INTEGRAL

    DEFF Research Database (Denmark)

    Lund, Niels; Budtz-Jørgensen, Carl; Westergaard, Niels Jørgen Stenfeldt

    2003-01-01

    The JEM-X monitor provides X-ray spectra and imaging with arcminute angular resolution in the 3 to 35 keV band. The good angular resolution and the low energy response of JEM-X plays an important role in the identification of gamma ray sources and in the analysis and scientific interpretation...

  4. Spatial variation of natural terrestrial γ-ray dose rates in Brunei

    International Nuclear Information System (INIS)

    Hu, S.J.; Lai, K.K.

    1998-01-01

    A carborne survey of natural terrestrial y-ray dose rates along the main roads of the western part of Brunei Darussalam was carried out using two portable type 1.5'φx4' NaI(T1) and 1'φx2' NaI(T1) scintillation counters. A series of semicontinuous count rates measurements were performed inside a moving vehicle. This yielded equal-distance data which were analysed statistically to obtain the spatial variation of the natural terrestrial γ-ray dose rates. The equal-distance data of dose rates were obtained by correcting for shielding effect of the car. The thickness of the pavement and the contribution from the pavement material were estimated from a correlation curve between the dose rates measured on pavements and on the nearby soils. A spectral analysis of the equal-distance data enabled us to clarify the structure of the spatial variation in dose rates. The data could be reasonably smoothened by removing the random noise components in a higher wave number region

  5. Monitoring of eye lens doses in radiation protection

    International Nuclear Information System (INIS)

    Bordy, J.M.

    2015-01-01

    Mainly due to the ICRP recommendation to decrease the exposure limit for eye lenses, the eye lens dosimetry has to be reconsidered. This paper gives an overview of the issues raised after this recommendation; that is to say, the choice and definition of the operational quantity to be monitored, the type testing and calibration of dosimeters aimed at measuring eyes lens 'doses', the design of existing eye lens dosimeters and their wearing conditions. Finally, a criterion to choose between a direct measurement of the personal dose equivalent at three millimeters depth, H p (3), with a dedicated dosimeter, and an indirect evaluation of H p (3) through whole-body monitoring is presented. (authors)

  6. Dose inspection and risk assessment on radiation safety for the use of non-medical X-ray machines in Taiwan

    Science.gov (United States)

    Hsu, Fang-Yuh; Hsu, Shih-Ming; Chao, Jiunn-Hsing

    2017-11-01

    The subject of this study is the on-site visits and inspections of facilities commissioned by the Atomic Energy Council (AEC) in Taiwan. This research was conducted to evaluate the possible dose and dose rate of cabinet-type X-ray equipment with nominal voltages of 30-150 kV and open-beam (portable or handheld) equipment, taking both normal operation and possibly abnormal operation conditions into account. Doses and dose rates were measured using a plastic scintillation survey meter and an electronic personal dosimeter. In total, 401 X-ray machines were inspected, including 139 units with nominal voltages of 30-50 kV X-ray equipment, 140 units with nominal voltages of 50-150 kV, and 122 open-beam (portable or handheld) X-ray equipment. The investigated doses for radiation workers and non-radiation workers operating cabinet-type X-ray equipment under normal safety conditions were all at the background dose level. Several investigated dose rates at the position of 10 cm away from the surface of open-beam (portable or handheld) X-ray equipment were very high, such X-ray machines are used by aeronautical police for the detection of suspected explosives, radiation workers are far away (at least 10 m away) from the X-ray machine during its operation. The doses per operation in X-ray equipment with a 30-50 kV nominal voltage were less than 1 mSv in all cases of abnormal use. Some doses were higher than 1 mSv per operation for X-ray equipment of 50-150 kV nominal voltage X-ray. The maximum dose rates at the beam exit have a very wide range, mostly less than 100 μSv/s and the largest value is about 3.92 mSv/s for open-beam (portable or handheld) X-ray devices. The risk induced by operating X-ray devices with nominal voltages of 30-50 kV is extremely low. The 11.5 mSv dose due to one operation at nominal voltage of 50-150 kV X-ray device is equivalent to the exposure of taking 575 chest X-rays. In the abnormal use of open-beam (portable or handheld) X-ray equipment, the

  7. Low dose X -ray effects on catalase activity in animal tissue

    Science.gov (United States)

    Focea, R.; Nadejde, C.; Creanga, D.; Luchian, T.

    2012-12-01

    This study was intended to investigate the effect of low-dose X ray-irradiation upon the activity of catalase (CAT) in freshly excised chicken tissues (liver, kidney, brain, muscle). The tissue samples were irradiated with 0.5Gy and 2Gy respectively, in a 6 MV photon beam produced by a clinical linear accelerator (VARIAN CLINAC 2100SC). The dose rate was of 260.88cGy/min. at 100 cm source to sample distance. The catalase level was assayed spectrophotometrically, based on reaction kinetics, using a catalase UV assay kit (SIGMA). Catalase increased activity in various tissue samples exposed to the studied X ray doses (for example with 24 % in the liver cells, pbonds that ensure the specificity of CAT active site) but the resulted balance of the two concurrent processes indicates the cell ability of decomposing the hydrogen peroxide-with benefits for the cell physiology restoration for the chosen low dose radiation.

  8. Required accuracy and dose thresholds in individual monitoring

    DEFF Research Database (Denmark)

    Christensen, P.; Griffith, R.V.

    1994-01-01

    this uncertainty factor, a value of 21% can be evaluated for the allowable maximum overall standard deviation for dose measurements at dose levels near the annual dose limits increasing to 45% for dose levels at the lower end of the dose range required to be monitored. A method is described for evaluating...... the overall standard deviation of the dosimetry system by combining random and systematic uncertainties in quadrature, and procedures are also given for determining each individual uncertainty connected to the dose measurement. In particular, attention is paid to the evaluation of the combined uncertainty due...... to energy and angular dependencies of the dosemeter. In type testing of personal dosimetry systems, the estimated overall standard deviation of the dosimetry system is the main parameter to be tested. An important characteristic of a personal dosimetry system is its capability of measuring low doses...

  9. Absorbed dose assessment in newborns during x-ray examinations

    Science.gov (United States)

    Taipe, Patricia K.; Berrocal, Mariella J.; Carita, Raúl F.

    2012-02-01

    Often a newborn presents breathing problems during the early days of life, i.e. bronchopneumonia, wich are caused in most of cases, by aspirating a mixture of meconium and amniotic fluid. In these cases, it is necessary to make use of a radiograph, requested by the physician to reach a diagnosis. This paper seeks to evaluate the absorbed doses in neonates undergoing a radiograph. For this reason we try to simulate the real conditions in a X-ray room from Lima hospitals. With this finality we perform a simulation made according a questionnaire related to technical data of X-ray equipment, distance between the source and the neonate, and its position to be irradiated. The information obtained has been used to determine the absorbed dose by infants, using the MCNP code. Finally, the results are compared with reference values of international health agencies.

  10. MOXE: An X-ray all-sky monitor for Soviet Spectrum-X-Gamma Mission

    Science.gov (United States)

    Priedhorsky, W.; Fenimore, E. E.; Moss, C. E.; Kelley, R. L.; Holt, S. S.

    1989-01-01

    A Monitoring Monitoring X-Ray Equipment (MOXE) is being developed for the Soviet Spectrum-X-Gamma Mission. MOXE is an X-ray all-sky monitor based on array of pinhole cameras, to be provided via a collaboration between Goddard Space Flight Center and Los Alamos National Laboratory. The objectives are to alert other observers on Spectrum-X-Gamma and other platforms of interesting transient activity, and to synoptically monitor the X-ray sky and study long-term changes in X-ray binaries. MOXE will be sensitive to sources as faint as 2 milliCrab (5 sigma) in 1 day, and cover the 2 to 20 KeV band.

  11. Gamma-ray dose rate increase at rainfall events and their air-mass origins

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2007-01-01

    The environmental γ-ray dose rate and precipitation rates were measured at our institute, in Rokkasho, Aomori, Japan. We analyzed 425 rainfall events in which the precipitation rate was over 0.5 mm from April through November during the years 2003 to 2005. Backward trajectories for 5 d starting from 1000 m above Rokkasho at the time of the maximum dose rate in a rainfall event, were calculated by using the HYSPLIT model of the NOAA Air Resources Laboratory. The trajectories for 5 d were classified by visual inspection according to the passage areas; Pacific Ocean, Asian Continent and Japan Islands. The increase of cumulative environmental γ-ray dose during a rainfall event was plotted against the precipitation in the event, and their relationship was separately examined according to the air-mass passage area, i.e. origin of the air-mass. Our results showed that the origin of air-mass was an important factor affecting the increase of environmental γ-ray dose rate by rainfall. (author)

  12. External dose rates from gamma rays and activity concentrations in foodstuffs and herbage in eastern Europe

    International Nuclear Information System (INIS)

    Wilkins, B.T.; Dodd, N.J.; Bradley, E.J.

    1986-01-01

    The initial scarcity of reliable information in eastern European countries, coupled with the proximity of the Chernobyl installation, resulted in understandable concern among British nationals living in these areas or visiting them on a short-term basis. Accordingly, arrangements were made by the Foreign and Commonwealth Office (FCO) for the appropriate Embassies to send samples of milk, drinking water, grass and available fruit and vegetables to the Board's laboratories at Chilton for analysis. In addition, simple monitoring equipment was supplied to the Embassies for measurements of external dose rates from gamma rays out of doors. The first set of samples was collected in Moscow on May 3rd 1986. Most consignments arrived at Chilton within 24 hours of collection. Speed was important, not only because of the need for information but because vegetation needed to be sufficiently fresh to permit meaningful measurement. By the end of June 1986, the results of systematic monitoring programmes in eastern Europe were being disseminated more freely, so that frequent sampling by the Embassies was no longer considered necessary. Since that time samples have been received only occasionally from those Embassies where concern still persists. This report summarises the results of measurements and samples taken by June 30th 1986. Data for γ-ray emitting radionuclides in foodstuffs were issued to the FCO in a series of Measurement Reports. Here they are presented together with data for actinide element concentrations in a limited number of samples. Measurements of outdoor external dose rates made by the Embassies are also included

  13. Calculating patient specific doses in X-ray diagnostics and from radiopharmaceuticals

    International Nuclear Information System (INIS)

    Lampinen, J.

    2000-01-01

    The risk associated with exposure to ionising radiation is dependent on the characteristics of the exposed individual. The size and structure of the individual influences the absorbed dose distribution in the organs. Traditional methods used to calculate the patient organ doses are based on standardised calculation phantoms, which neglect the variance of the patient size or even sex. When estimating the radiation dose of an individual patient, patient specific calculation methods must be used. Methods for patient specific dosimetry in the fields of X-ray diagnostics and diagnostic and therapeutic use of radiopharmaceuticals were proposed in this thesis. A computer program, ODS-60, for calculating organ doses from diagnostic X-ray exposures was presented. The calculation is done in a patient specific phantom with depth dose and profile algorithms fitted to Monte Carlo simulation data from a previous study. Improvements to the version reported earlier were introduced, e.g. bone attenuation was implemented. The applicability of the program to determine patient doses from complex X-ray examinations (barium enema examination) was studied. The conversion equations derived for female and male patients as a function of patient weight gave the smallest deviation from the actual patient doses when compared to previous studies. Another computer program, Intdose, was presented for calculation of the dose distribution from radiopharmaceuticals. The calculation is based on convolution of an isotope specific point dose kernel with activity distribution, obtained from single photon emission computed tomography (SPECT) images. Anatomical information is taken from magnetic resonance (MR) or computed tomography (CT) images. According to a phantom study, Intdose agreed within 3 % with measurements. For volunteers administered diagnostic radiopharmaceuticals, the results given by Intdose were found to agree with traditional methods in cases of medium sized patients. For patients

  14. Gamma-ray detectors for intelligent, hand-held radiation monitors

    International Nuclear Information System (INIS)

    Fehlau, P.E.

    1983-01-01

    Small radiation detectors based on HgI 2 , bismuth germanate (BGO), plastic, or NaI(Tl) detector materials were evaluated for use in small, lighweight radiation monitors. The two denser materials, HgI 2 and BGO, had poor resolution at low-energy and thus performed less well than NaI(Tl) in detecting low-energy gamma rays from bare, enriched uranium. The plastic scintillator, a Compton recoil detector, also performed less well at low gamma-ray energy. Two small NaI(Tl) detectors were suitable for detecting bare uranium and sheilded plutonium. One became part of a new lightweight hand-held monitor and the other found uses as a pole-mounted detector for monitoring hard-to-reach locations

  15. Darwin: Dose monitoring system applicable to various radiations with wide energy ranges

    International Nuclear Information System (INIS)

    Sato, T.; Satoh, D.; Endo, A.; Yamaguchi, Y.

    2007-01-01

    A new radiation dose monitor, designated as DARWIN (Dose monitoring system Applicable to various Radiations with Wide energy ranges), has been developed for real-time monitoring of doses in workspaces and surrounding environments of high-energy accelerator facilities. DARWIN is composed of a Phoswitch-type scintillation detector, which consists of liquid organic scintillator BC501A coupled with ZnS(Ag) scintillation sheets doped with 6 Li, and a data acquisition system based on a Digital-Storage-Oscilloscope. DARWIN has the following features: (1) capable of monitoring doses from neutrons, photons and muons with energies from thermal energy to 1 GeV, 150 keV to 100 MeV and 1 MeV to 100 GeV, respectively, (2) highly sensitive with precision and (3) easy to operate with a simple graphical user-interface. The performance of DARWIN was examined experimentally in several radiation fields. The results of the experiments indicated the accuracy and wide response range of DARWIN for measuring dose rates from neutrons, photons and muons with wide energies. It was also found from the experiments that DARWIN enables us to monitor small fluctuations of neutron dose rates near the background level because of its high sensitivity. With these properties, DARWIN will be able to play a very important role for improving radiation safety in high-energy accelerator facilities. (authors)

  16. Wireless monitoring system for personal dose

    International Nuclear Information System (INIS)

    Kobayashi, Hironobu; Kawamura, Takeshi; Inoue, Takayuki

    2000-01-01

    Fuji Electric has developed a system for the higher radiation controlled area in nuclear power plants, in which exposure dose data measured on the wearer's chest, hands, and legs are transferred by wireless to the data control equipment so that the exposure dose can be controlled in real time. The system using a specified low-power radio wave causes no interference to the other types of dosimeters. The data control equipment automatically saves data received from the dosimeters and also has functions of calibration of dosimeters and maintenance of the wireless system. This paper describes the wireless monitoring system that consists of chest and parts dosimeters and data control equipment. (author)

  17. Standardization of high-dose measurement of electron and gamma ray absorbed doses and dose rates

    International Nuclear Information System (INIS)

    McLaughlin, W.L.

    1985-01-01

    Intense electron beams and gamma radiation fields are used for sterilizing medical devices, treating municipal wastes, processing industrial goods, controlling parasites and pathogens, and extending the shelf-life of foods. Quality control of such radiation processes depends largely on maintaining measurement quality assurance through sound dosimetry procedures in the research leading to each process, in the commissioning of that process, and in the routine dose monitoring practices. This affords documentation as to whether satisfactory dose uniformity is maintained throughout the product and throughout the process. Therefore, dosimetry at high doses and dose rates must in many radiation processes be standardized carefully, so that 'dosimetry release' of a product is verified. This standardization is initiated through preliminary dosimetry intercomparison studies such as those sponsored recently by the IAEA. This is followed by establishing periodic exercises in traceability to national or international standards of absorbed dose and dose rate. Traceability is achieved by careful selection of dosimetry methods and proven reference dosimeters capable of giving sufficiently accurate and precise 'transfer' dose assessments: (1) they must be calibrated or have well-established radiation-yield indices; (2) their radiation response characteristics must be reproducible and cover the dose range of interest; (3) they must withstand the rigours of back-and-forth mailing between a central standardizing laboratory and radiation processing facilities, without excessive errors arising due to instabilities, dosimeter batch non-uniformities, and environmental and handling stresses. (author)

  18. 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.

  19. 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)

  20. A study of gonad doses in X-ray radiographic examinations of the abdomen

    International Nuclear Information System (INIS)

    Brown, L.D.

    1980-01-01

    A phantom study has been made in an attempt to redetermine gonad dose associated with routine X-ray diagnostic procedures. Over a range of voltages between 60 kVp and 130 kVp, TLD measurements of skin, ovary, a standardised cassette dose of 1 mrad, and testicle doses were obtained for AP, PA and lateral radiographs. Whilst exact numerical results depended greatly on the characteristics of the film-screen combination used, the contrast required in the final radiograph and the efficiency of the Bucky grid, results of this redetermination did not support the view that a reduction in population genetic dose would follow any general increase in the typical operating potential used for abdominal x-ray examinations. (U.K.)

  1. Real-Time Patient and Staff Radiation Dose Monitoring in IR Practice

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, Anna M., E-mail: karmanna@stanford.edu; Paulis, Leonie, E-mail: leonie.paulis@mumc.nl; Vergoossen, Laura; Kovac, Axel O., E-mail: axel.kovac@mumc.nl; Wijnhoven, Geert, E-mail: g.wijnhoven@mumc.nl [Maastricht University Medical Centre, Department of Radiology (Netherlands); Schurink, Geert Willem H., E-mail: gwh.schurink@mumc.nl; Mees, Barend, E-mail: barend.mees@mumc.nl [Maastricht University Medical Centre, Department of Vascular Surgery (Netherlands); Das, Marco, E-mail: m.das@mumc.nl; Wildberger, Joachim E., E-mail: j.wildberger@mumc.nl; Haan, Michiel W. de, E-mail: m.de.haan@mumc.nl; Jeukens, Cécile R. L. P. N., E-mail: cecile.jeukens@mumc.nl [Maastricht University Medical Centre, Department of Radiology (Netherlands)

    2017-03-15

    PurposeKnowledge of medical radiation exposure permits application of radiation protection principles. In our center, the first dedicated real-time, automated patient and staff dose monitoring system (DoseWise Portal, Philips Healthcare) was installed. Aim of this study was to obtain insight in the procedural and occupational doses.Materials and MethodsAll interventional radiologists, vascular surgeons, and technicians wore personal dose meters (PDMs, DoseAware, Philips Healthcare). The dose monitoring system simultaneously registered for each procedure dose-related data as the dose area product (DAP) and effective staff dose (E) from PDMs. Use and type of shielding were recorded separately. All procedures were analyzed according to procedure type; these included among others cerebral interventions (n = 112), iliac and/or caval venous recanalization procedures (n = 68), endovascular aortic repair procedures (n = 63), biliary duct interventions (n = 58), and percutaneous gastrostomy procedure (n = 28).ResultsMedian (±IQR) DAP doses ranged from 2.0 (0.8–3.1) (percutaneous gastrostomy) to 84 (53–147) Gy cm{sup 2} (aortic repair procedures). Median (±IQR) first operator doses ranged from 1.6 (1.1–5.0) μSv to 33.4 (12.1–125.0) for these procedures, respectively. The relative exposure, determined as first operator dose normalized to procedural DAP, ranged from 1.9 in biliary interventions to 0.1 μSv/Gy cm{sup 2} in cerebral interventions, indicating large variation in staff dose per unit DAP among the procedure types.ConclusionReal-time dose monitoring was able to identify the types of interventions with either an absolute or relatively high staff dose, and may allow for specific optimization of radiation protection.

  2. X-ray conditions and response characteristics of automatic dose control in cinematography

    International Nuclear Information System (INIS)

    Arai, Hiroaki

    1997-01-01

    X-ray characteristics including subject thickness (copper plate), tube voltage, tube current and irradiation time were measured at stability, with an automatic dose control x-ray generator for cineangiography. Regardless of subject thickness, it is possible that the energy input to the x-ray tube in one frame may be decreased. The automatic control response was measured after rapid fluctuation in subject thickness. Two inverter-type x-ray generators with different automatic control units were studied. The older control unit changes exposure dose by tube voltage and tube current, while the newer one changes exposure dose by tube voltage, tube current and irradiation time. The maximum rate of change in tube voltage is greater with the newer control unit. In addition, the actual tube current response of the newer control unit in increasing nominal value is faster than the older one. In the new control unit, for each pulse, irradiation is cut off by means of a signal that the exposure has reached the proper value. Thus given the same differential in subject thickness, the newer control unit resumed stability faster than the older one. (author)

  3. X-ray conditions and response characteristics of automatic dose control in cinematography

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Hiroaki [Cardiovascular Institute Hospital, Tokyo (Japan)

    1997-11-01

    X-ray characteristics including subject thickness (copper plate), tube voltage, tube current and irradiation time were measured at stability, with an automatic dose control x-ray generator for cineangiography. Regardless of subject thickness, it is possible that the energy input to the x-ray tube in one frame may be decreased. The automatic control response was measured after rapid fluctuation in subject thickness. Two inverter-type x-ray generators with different automatic control units were studied. The older control unit changes exposure dose by tube voltage and tube current, while the newer one changes exposure dose by tube voltage, tube current and irradiation time. The maximum rate of change in tube voltage is greater with the newer control unit. In addition, the actual tube current response of the newer control unit in increasing nominal value is faster than the older one. In the new control unit, for each pulse, irradiation is cut off by means of a signal that the exposure has reached the proper value. Thus given the same differential in subject thickness, the newer control unit resumed stability faster than the older one. (author)

  4. The background simulations for the integral X-ray monitor JEM-X

    DEFF Research Database (Denmark)

    Feroci, M.; Rapisarda, M.; Costa, E.

    1999-01-01

    The JEM-X experiment (Joint European X-ray Monitor, Lund et al. (1998) and Westergaard and Lund (1998)) is the X-ray monitor of the INTEGRAL satellite. It is a coded aperture, high pressure microstrip proportional counter. It will operate in the primary energy range from 3 to 35 keV (with...

  5. Exploratory X-ray Monitoring of z>4 Radio-Quiet Quasars

    Science.gov (United States)

    Shemmer, Ohad

    2017-09-01

    We propose to extend our exploratory X-ray monitoring project of some of the most distant radio-quiet quasars by obtaining one snapshot observation per Cycle for each of four sources at z>4. Combining these observations with six available X-ray epochs per source will provide basic temporal information over rest-frame timescales of 3-5 yr. We are supporting this project with Swift monitoring of luminous radio-quiet quasars at z=1.3-2.7 to break the L-z degeneracy and test evolutionary scenarios of the central engine in active galactic nuclei. Our ultimate goal is to provide a basic assessment of the X-ray variability properties of luminous quasars at the highest accessible redshifts that will serve as the benchmark for X-ray variability studies of such sources with future X-ray missions.

  6. Evaluation of TLD dose response compared to MCNP-5 simulation of diagnostic X ray equipment - radiation diagnostic image

    International Nuclear Information System (INIS)

    Sanchez G, R.; Cavalieri, T. A.; De Paiva, F.; Dalledone S, P. de T.; Yoriyaz, H.; Rodrigues F, M. A.; Vivolo, V.

    2014-08-01

    The thermo luminescent dosimeter (TLD) is used as a radiation dosimeter and can be used as environmental and staff personnel monitoring. The TLD measures ionizing radiation exposure by a process in which the amount of radiation collected by the dosimeter is converted in visible light when the crystal is heated. The amount of emitted light is proportional to the radiation exposure, and then the response of the TLD must be the related to the real dose. In this work it was used twenty four TLD 700 in order to obtain eight values of doses from a diagnostic X-ray equipment. The TLD-700 is a LiF TLD enriched with 7 Li isotope. One way to compare and study the response of TLD is by Monte Carlo method, which has been used as a computational tool to solve problems stochastically. This method can be applied to any geometry, even those where the boundary conditions are unknown, making the method particularly useful to solve problems a priori. In this work it was modeled the X-ray tube exactly as the one used to irradiate the TLD, after the simulation and the TLD irradiation the results of dose value from both were compared. (Author)

  7. Evaluation of TLD dose response compared to MCNP-5 simulation of diagnostic X ray equipment - radiation diagnostic image

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez G, R.; Cavalieri, T. A.; De Paiva, F.; Dalledone S, P. de T.; Yoriyaz, H. [Instituto de Pesquisas Energeticas e Nucleares, Centro de Engenharia Nuclear / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Rodrigues F, M. A. [Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Dermatologia e Radioterapia, Av. Prof. Montenegro s/n, Rubiao Junior, 18601-970 Botucatu (Brazil); Vivolo, V., E-mail: chancez@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares, Gerencia de Metrologia das Radiacoes / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The thermo luminescent dosimeter (TLD) is used as a radiation dosimeter and can be used as environmental and staff personnel monitoring. The TLD measures ionizing radiation exposure by a process in which the amount of radiation collected by the dosimeter is converted in visible light when the crystal is heated. The amount of emitted light is proportional to the radiation exposure, and then the response of the TLD must be the related to the real dose. In this work it was used twenty four TLD 700 in order to obtain eight values of doses from a diagnostic X-ray equipment. The TLD-700 is a LiF TLD enriched with {sup 7}Li isotope. One way to compare and study the response of TLD is by Monte Carlo method, which has been used as a computational tool to solve problems stochastically. This method can be applied to any geometry, even those where the boundary conditions are unknown, making the method particularly useful to solve problems a priori. In this work it was modeled the X-ray tube exactly as the one used to irradiate the TLD, after the simulation and the TLD irradiation the results of dose value from both were compared. (Author)

  8. Monte Carlo simulation on hard X-ray dose produced in interaction between high intensity laser and solid target

    International Nuclear Information System (INIS)

    Yang Bo; Qiu Rui; Li Junli; Zhang Hui

    2014-01-01

    The X-ray dose produced in the interaction between high intensity laser and solid target was studied by simulation using Monte Carlo code. Compared with experimental results, the calculation model was verified. The calculation model was used to study the effect on X-ray dose with different electron temperatures, target materials (including Au, Cu and PE) and thicknesses. The results indicate that the X-ray dose is mainly determined by the electron temperature, and will be affected by the target parameters. X-ray dose of Au is about 1.2 times that of Cu, and is about 5 times that of PE (polyethylene). In addition, compared with other target thickness, when target thickness is the mean range of electron in the target, X-ray dose is relatively large. These results will provide references on evaluating the ionizing radiation dose for laser devices. (authors)

  9. Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

    Energy Technology Data Exchange (ETDEWEB)

    Ono, K.; Akahane, K.; Aota, T.; Hada, M.; Takano, Y.; Kai, M.; Kusama, T

    2003-07-01

    The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates. (author)

  10. Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

    International Nuclear Information System (INIS)

    Ono, K.; Akahane, K.; Aota, T.; Hada, M.; Takano, Y.; Kai, M.; Kusama, T.

    2003-01-01

    The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates. (author)

  11. Instrumentation for continuous monitoring of low energy cosmic ray intensity

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S; Prasad, R; Yadav, R S [Aligarh Muslim Univ. (India). Dept. of Physics; Naqvi, T H [Z.H. Engineering Coll., Aligarh (India); Ahmed, Rais [National Council of Educational Research and Training, New Delhi (India)

    1975-12-01

    A high counting rate neutron monitor developed at Aligarh for continuous monitoring of low energy nucleonic component of cosmic rays is described. Transistorized electronic circuits used are described.

  12. Monitoring of radiolytic degradation of benzo(a)pyrene using γ-rays in aqueous media by HPLC

    International Nuclear Information System (INIS)

    Butt, S. Bilal; Qureshi, Rashid N.; Ahmed, Shafaat

    2005-01-01

    Poly nuclear aromatic hydrocarbons (PAHs) are generated in the environment by various industrial processes and anthropogenic activities. These compounds are quite stable and persist in the environment due to the aromatic bonding within the rings. Benzo(a)pyrene (B(a)P) is a potential carcinogenic and conditions for its degradation have been optimized by investigating γ-ray dose intensity, its concentration effect and the influence of surfactant presence. HPLC has been used to monitor the degree of degradation of B(a)P under the optimum conditions

  13. Mixed field dose equivalent measuring instruments

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; McDonald, J.C.; Endres, G.W.R.; Quam, W.

    1985-01-01

    In the past, separate instruments have been used to monitor dose equivalent from neutrons and gamma rays. It has been demonstrated that it is now possible to measure simultaneously neutron and gamma dose with a single instrument, the tissue equivalent proportional counter (TEPC). With appropriate algorithms dose equivalent can also be determined from the TEPC. A simple ''pocket rem meter'' for measuring neutron dose equivalent has already been developed. Improved algorithms for determining dose equivalent for mixed fields are presented. (author)

  14. Development of miniature γ dose rate monitor with high sensitivity

    International Nuclear Information System (INIS)

    Shi Huilu; Tuo Xianguo; Xi Dashun; Tang Rong; Mu Keliang; Yang Jianbo

    2009-01-01

    This paper introduces a miniature γ dose rate monitor with high sensitivity which design based on single chip microcomputer, it can continue monitoring γ dose rate and then choose wire or wireless communications to sent the monitoring data to host according to the actual conditions. It has two kinds of power supply system, AC power supply system and battery which can be chose by concrete circumstances. The design idea and implementation technology of hardware and software and the system structure of the monitor are detailed illustrated in this paper. The experimental results show that measurable range is 0.1 mR/h-200 mR/h, the sensitivity of γ is 90 cps/mR/h, dead time below 200 us, error of stability below ±10%. (authors)

  15. Optimum power of radiation dose in X ray television systems of flaw inspection in industry

    International Nuclear Information System (INIS)

    Denbnovetskii, S.V.; Troitskii, V.A.; Belyi, N.G.; Grom, V.S.; Kuz'micheva, N.V.; Leshchishin, A.V.; Mikhailov, V.N.; Shutenko, O.V.

    1990-01-01

    The authors present the experimental dose characteristics of a x ray television system based on x ray vidicons with the diameter of the working field of 900 mm which operate in the continuous and pulsed conditions with the longer time of cumulation of radiation images on the target of the x ray vidicon. For each type of the inspected material, its thickness, and cumulation time, the dose characteristics were used to determine the optimum power of the exposure dose ensuring the maximum signal/noise ratio and detectability of the defects at the output of the system. (author)

  16. Characterization of the adaptive response to ionizing radiation induced by low doses of X-rays to Vibrio cholerae cells

    International Nuclear Information System (INIS)

    Basak, Jayasri

    1996-01-01

    Pretreatment with sublethal doses of X-rays induced an adaptive response in Vibrio cholerae cells as indicated by their greater resistance to the subsequent challenging doses of X-irradiation. The adaptive response was maximum following a pre-exposure dose of 1.7 Gy X-rays and an optimum incubation period of 40 min at 37C. Pre-exposure to a sublethal dose of 1.7 Gy X-rays made the Vibrio cholerae cells 3.38-fold more resistant to the subsequent challenge by X-rays. Pretreatment with a sublethal dose of hydrogen peroxide offered a similar degree of protection to the bacterial cells against subsequent treatment with challenging doses of X-ray radiation. However, exposure of Vibrio cholerae cells to mild heat (42C for 10 min) before X-ray irradiation decreased their survival following X-irradiation

  17. Rapid, low dose X-ray diffractive imaging of the malaria parasite Plasmodium falciparum

    International Nuclear Information System (INIS)

    Jones, Michael W.M.; Dearnley, Megan K.; Riessen, Grant A. van; Abbey, Brian; Putkunz, Corey T.; Junker, Mark D.; Vine, David J.; McNulty, Ian; Nugent, Keith A.; Peele, Andrew G.; Tilley, Leann

    2014-01-01

    Phase-diverse X-ray coherent diffractive imaging (CDI) provides a route to high sensitivity and spatial resolution with moderate radiation dose. It also provides a robust solution to the well-known phase-problem, making on-line image reconstruction feasible. Here we apply phase-diverse CDI to a cellular sample, obtaining images of an erythrocyte infected by the sexual stage of the malaria parasite, Plasmodium falciparum, with a radiation dose significantly lower than the lowest dose previously reported for cellular imaging using CDI. The high sensitivity and resolution allow key biological features to be identified within intact cells, providing complementary information to optical and electron microscopy. This high throughput method could be used for fast tomographic imaging, or to generate multiple replicates in two-dimensions of hydrated biological systems without freezing or fixing. This work demonstrates that phase-diverse CDI is a valuable complementary imaging method for the biological sciences and ready for immediate application. - Highlights: • Phase-diverse coherent X-ray diffraction microscopy provides high-resolution and high-contrast images of intact biological samples. • Rapid nanoscale resolution imaging is demonstrated at orders of magnitude lower dose than previously possible. • Phase-diverse coherent X-ray diffraction microscopy is a robust technique for rapid, quantitative, and correlative X-ray phase imaging

  18. Rapid, low dose X-ray diffractive imaging of the malaria parasite Plasmodium falciparum

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Michael W.M., E-mail: michael.jones@latrobe.edu.au [ARC Centre of Excellence for Coherent X-Ray Science, Department of Physics, La Trobe University, Victoria 3086 (Australia); Dearnley, Megan K. [ARC Centre of Excellence for Coherent X-Ray Science, Department of Biochemistry and Molecular Biology, Bio21 Institute, The University of Melbourne, Victoria 3010 (Australia); Riessen, Grant A. van [ARC Centre of Excellence for Coherent X-Ray Science, Department of Physics, La Trobe University, Victoria 3086 (Australia); Abbey, Brian [ARC Centre of Excellence for Coherent X-Ray Science, Department of Physics, La Trobe University, Victoria 3086 (Australia); Melbourne Centre for Nanofabrication, Victoria 3168 (Australia); Putkunz, Corey T. [ARC Centre of Excellence for Coherent X-Ray Science, School of Physics, The University of Melbourne, Victoria 3010 (Australia); Junker, Mark D. [ARC Centre of Excellence for Coherent X-Ray Science, Department of Physics, La Trobe University, Victoria 3086 (Australia); Vine, David J. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); McNulty, Ian [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Centre for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Nugent, Keith A. [ARC Centre of Excellence for Coherent X-Ray Science, Department of Physics, La Trobe University, Victoria 3086 (Australia); Peele, Andrew G. [ARC Centre of Excellence for Coherent X-Ray Science, Department of Physics, La Trobe University, Victoria 3086 (Australia); Australian Synchrotron, 800 Blackburn Road, Clayton 3168 (Australia); Tilley, Leann [ARC Centre of Excellence for Coherent X-Ray Science, Department of Biochemistry and Molecular Biology, Bio21 Institute, The University of Melbourne, Victoria 3010 (Australia)

    2014-08-01

    Phase-diverse X-ray coherent diffractive imaging (CDI) provides a route to high sensitivity and spatial resolution with moderate radiation dose. It also provides a robust solution to the well-known phase-problem, making on-line image reconstruction feasible. Here we apply phase-diverse CDI to a cellular sample, obtaining images of an erythrocyte infected by the sexual stage of the malaria parasite, Plasmodium falciparum, with a radiation dose significantly lower than the lowest dose previously reported for cellular imaging using CDI. The high sensitivity and resolution allow key biological features to be identified within intact cells, providing complementary information to optical and electron microscopy. This high throughput method could be used for fast tomographic imaging, or to generate multiple replicates in two-dimensions of hydrated biological systems without freezing or fixing. This work demonstrates that phase-diverse CDI is a valuable complementary imaging method for the biological sciences and ready for immediate application. - Highlights: • Phase-diverse coherent X-ray diffraction microscopy provides high-resolution and high-contrast images of intact biological samples. • Rapid nanoscale resolution imaging is demonstrated at orders of magnitude lower dose than previously possible. • Phase-diverse coherent X-ray diffraction microscopy is a robust technique for rapid, quantitative, and correlative X-ray phase imaging.

  19. Instrumentation for continuous monitoring of low energy cosmic ray intensity

    International Nuclear Information System (INIS)

    Kumar, S.; Prasad, R.; Yadav, R.S.; Ahmed, Rais

    1975-01-01

    A high counting rate neutron monitor developed at Aligarh for continuous monitoring of low energy nucleonic component of cosmic rays is described. Transistorized electronic circuits used are described. (author)

  20. The D1 method: career dose estimation from a combination of historical monitoring data and a single year's dose data

    International Nuclear Information System (INIS)

    Sont, W.N.

    1995-01-01

    A method is introduced to estimate career doses from a combination of historical monitoring data and a single year's dose data. This method, called D1 eliminates the bias arising from incorporating historical dose data from times when occupational doses were generally much higher than they are today. Doses calculated by this method are still conditional on the preservation of the status quo in the effectiveness of radiation protection. The method takes into account the variation of the annual dose, and of the probability of being monitored, with the time elapsed since the start of a career. It also allows for the calculation of a standard error of the projected career dose. Results from recent Canadian dose data are presented. (author)

  1. 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

  2. Extremity doses of medical staff involved in interventional radiology and cardiology: Correlations and annual doses (hands and legs)

    International Nuclear Information System (INIS)

    Krim, S.; Brodecki, M.; Carinou, E.; Donadille, L.; Jankowski, J.; Koukorava, C.; Dominiek, J.; Nikodemova, D.; Ruiz-Lopez, N.; Sans-Merce, M.; Struelens, L.; Vanhavere, F.

    2011-01-01

    An intensive measurement campaign was launched in different hospitals in Europe within work package 1 of the ORAMED project (Optimization of RAdiation protection for MEDical staff). Its main objective was to obtain a set of standardized data on extremity and eye lens doses for staff in interventional radiology (IR) and cardiology (IC) and to optimize staff protection. The monitored procedures were divided in three main categories: cardiac, general angiography and endoscopic retrograde cholangio-pancreatography(ERCP) procedures. Using a common measurement protocol, information such as the protective equipment used (lead table curtain, transparent lead glass ceiling screen, patient shielding, whole body shielding or special cabin etc.) as well as Kerma Area Product (KAP) values and access of the catheter were recorded. This study was performed with a final database of more than 1300 procedures performed in 34 European hospitals. Its objectives were firstly to determine if the measured extremity doses could be correlated to the KAP values; secondly to check if the doses to the eyes could be linked to the doses to the hands (finger or wrist positions) and finally if the doses to the fingers could be estimated based on the doses to the wrists. General correlations were very difficult to find and their strength was mostly influenced by three main parameters: the X-ray tube configuration, the room collective radioprotective equipment and the access of the catheter. The KAP value can provide a simple mean to estimate the extremity doses of the operator given that it is assessed correctly for the operator when he is actually using the X-ray tube. Moreover, this study showed that the doses to the left finger are strongly correlated to the doses to the left wrist when no ceiling shield is used. It is also possible to estimate the doses to the eyes given the doses to the left finger or left wrist but the X-ray tube configuration and the access have to be considered. The annual

  3. Development of dose monitoring system applicable to various radiations with wide energy ranges

    International Nuclear Information System (INIS)

    Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Yamaguchi, Yasuhiro

    2005-01-01

    A new inventive radiation dose monitor, designated as DARWIN (Dose monitoring system Applicable to various Radiations with WIde energy raNges), has been developed for monitoring doses in workspaces and surrounding environments of high energy accelerator facilities. DARWIN is composed of a phoswitch-type scintillation detector, which consists of liquid organic scintillator BC501A coupled with ZnS(Ag) scintillation sheets doped with 6 Li, and a data acquisition system based on a Digital-Storage-Oscilloscope. Scintillations from the detector induced by thermal and fast neutrons, photons and muons were discriminated by analyzing their waveforms, and their light outputs were directly converted into the corresponding doses by applying the G-function method. Characteristics of DARWIN were studied by both calculation and experiment. The calculated results indicate that DARWIN gives reasonable estimations of doses in most radiation fields. It was found from the experiment that DARWIN has an excellent property of measuring doses from all particles that significantly contribute to the doses in surrounding environments of accelerator facilities - neutron, photon and muon with wide energy ranges. The experimental results also suggested that DARWIN enables us to monitor small fluctuation of neutron dose rates near the background-level owing to its high sensitivity. (author)

  4. Calibration procedures of area monitors in terms of the Ambient Dose Equivalent H*(10), for gamma, x-ray radiation fields

    International Nuclear Information System (INIS)

    Dieguez Davila, L.E.

    1998-01-01

    In the present thesis procedures for calibrating portable survey meters in terms of the new ICRU quantities H*(10) ambient dose equivalent are discussed. Also the remendations of International Comission on Radiation Protection in their report ICRP 60 that inludes the operational magnitudes that the International Comission of Radiation Units proposed for calibrating area monitors

  5. Inhibitory mechanism of low-dose, whole-body irradiation with gamma-rays against tumor metastasis

    International Nuclear Information System (INIS)

    Yasuhiro Ohsima; Mitsutoshi Tukimoto; Shuji Kojima

    2007-01-01

    Complete text of publication follows. A lot of beneficial effects of low-dose irradiation are well known. Of them, an inhibitory effect of the radiation on lung metastasis is reported so far. It has been reported that low-dose whole-body irradiation with gamma rays enhanced cytotoxic immune response as one of the mechanisms. In our laboratory, it has been confirmed an enhancement of natural killer activity in mice irradiated with whole-body 0.5Gy gamma-rays. Metastasis is accomplished by multistep process, involving basement membrane destruction, local invasion, intravasation, survival in the bloodstream, extravasation into distant organs, and proliferation at the target site. Besides, a lot of growth factors and proteases are involved in these steps. As to mechanism of inhibition of tumor metastasis induced by low-dose whole-body irradiation, studies from the standpoint of tumor invasion have not been reported. Here, inhibitory effect of 0.5Gy whole-body gamma-ray irradiation on tumor metastasis and its mechanism were examined in pulmonary metastasis model mice injected with B16 melanoma cells. Consequently, 0.5Gy whole-body gamma ray irradiation significantly suppressed colony formation in the lungs. Expression of matrix metalloproteinase- 2 (MMP- 2), a proteinase related to metastasis, in lung tissues was suppressed by the radiation. Alteration of tissue inhibitor of matrix metalloproteinase (TIMP) after the gamma-ray irradiation was examined. Expression of TIMP-1 and TIMP-2 mRNA in the lungs were significantly increased. In order to clarify the inhibitory effect obtained in the in vivo metastatic lung cancer model mice, we studied effects of gamma-rays on cell proliferation, alterations of mRNA and proteins related to tumor metastasis in cultured B16 melanoma cells. Proliferation of B16 melanoma cells was decreased in a dose-dependent manner. MMP-2 mRNA expression was not altered in any doses of gamma-rays. Thought expression of the protein was slightly

  6. Monitor units are not predictive of neutron dose for high-energy IMRT

    Directory of Open Access Journals (Sweden)

    Hälg Roger A

    2012-08-01

    Full Text Available Abstract Background Due to the substantial increase in beam-on time of high energy intensity-modulated radiotherapy (>10 MV techniques to deliver the same target dose compared to conventional treatment techniques, an increased dose of scatter radiation, including neutrons, is delivered to the patient. As a consequence, an increase in second malignancies may be expected in the future with the application of intensity-modulated radiotherapy. It is commonly assumed that the neutron dose equivalent scales with the number of monitor units. Methods Measurements of neutron dose equivalent were performed for an open and an intensity-modulated field at four positions: inside and outside of the treatment field at 0.2 cm and 15 cm depth, respectively. Results It was shown that the neutron dose equivalent, which a patient receives during an intensity-modulated radiotherapy treatment, does not scale with the ratio of applied monitor units relative to an open field irradiation. Outside the treatment volume at larger depth 35% less neutron dose equivalent is delivered than expected. Conclusions The predicted increase of second cancer induction rates from intensity-modulated treatment techniques can be overestimated when the neutron dose is simply scaled with monitor units.

  7. Dose reduction by x-ray beam filtration in screen-film radiography

    International Nuclear Information System (INIS)

    Koedooder, C.

    1986-01-01

    This thesis describes experimental and theoretical aspects of dose reduction by x-ray beam filtration in screen-film radiography. The thesis deals mainly with dose reduction under the constraint of constant image quality; an analytical approach is chosen. Therefore, part of the thesis deals with the development of an algorithm to calculate patient dose and exposure for different filter materials and different tube load conditions, under the constraint of constant contrast and constant optical density. (Auth.)

  8. Radiation control monitoring system on the High Temperature Engineering Test Reactor

    International Nuclear Information System (INIS)

    Minowa, Y.; Nakazawa, T.; Sato, K.; Kikuchi, H.; Nomura, T.

    1999-01-01

    Radiation control monitoring system of the HTTR is divided into three subsystems; exhaust monitoring equipment, room air monitoring equipment, dose equivalent rate monitoring equipment. The exhaust monitoring equipment consists of exhaust gas monitors, exhaust dust monitors, and a tritium and carbon sampling device at normal operation of the reactor. Accident gas monitors are also provided for the emergency. The tritium and carbon sampling device uses cupper oxide as a oxidizer, and ethanol amine as a sampling materials which collects continuously tritium and carbon in dust during about one month and is measured by a liquid scintillation counter. The accident gas monitors consist of two channels, for a low and a high range. The high range-gas monitor consists of two ionization chambers: one encloses argon gas and the other encloses xenon gas. Average energy of various gamma-rays, hence, accident exposure dose of the public can be estimated with the comparison of the sensitivity of two kinds of ionization chambers. The dose equivalent rate monitoring equipment consists of silicon semiconductor detectors for gamma-ray, a ionization chamber for gamma-ray, a BF 3 counter for neutron, and accident area monitors which are located in the reactor container. The message of 'check dose !' or 'temporary evacuation !' can be send to the workers in the reactor with a light and a sound. A computer system collects the radiation monitoring data every 10 sec cycle and accumulates them in a server computer. The leakage and the dispersion of helium gas must be taken into account on the radiation control monitoring system of the HTTR. (Suetake, M.)

  9. Estimation of the population dose from medical X-ray diagnostic examination in Shandong province, China

    International Nuclear Information System (INIS)

    Su Xieming

    1985-01-01

    The exposure doses on the examinated body surface for verious types of X-ray diagnostic examanition in Shandong Province were surveyed. The collective effective dose equivalent in per million population were calculated with the measured results, the ratios of orga absorbed doses to irradiated surface exposure doses and the frequencies of X-ray examination in Shandong Province. The result was 326 man.Sv per million total population in 1980, of which chest fluoroscopies. lumbar spine radiographies and G.I. examination were estimated to be about 78, 9 and 5 precent, respectively

  10. Creation and clinical application of real-time dose monitor using dose area product meter

    International Nuclear Information System (INIS)

    Matsubara, Kosuke; Uoyama, Yoshinori; Iida, Hiroji; Mizushima, Takashi

    2004-01-01

    The management of patient dose has become more of an issue in recent years. Dose can be determined non-invasively and in real time through the use of a dose area product meter, but it is the area dose value that is obtained. Therefore, we created a program that estimates entrance skin dose (ESD) in real time from area dose values obtained during procedures. We used Microsoft Visual C++ 6.0 (Standard Edition) for the programming language and C language for the programming environment. The value was a maximum 285.4 mGy at ileus tube insertion when measuring ESD for radiography of the digestive organ and non-vascular type interventional radiology (IVR) using the created program and seeking the average according to the procedures. The program that we created can be considered valid for monitoring ESD correctly and in real time. (author)

  11. Low-dose X-ray CT reconstruction via dictionary learning.

    Science.gov (United States)

    Xu, Qiong; Yu, Hengyong; Mou, Xuanqin; Zhang, Lei; Hsieh, Jiang; Wang, Ge

    2012-09-01

    Although diagnostic medical imaging provides enormous benefits in the early detection and accuracy diagnosis of various diseases, there are growing concerns on the potential side effect of radiation induced genetic, cancerous and other diseases. How to reduce radiation dose while maintaining the diagnostic performance is a major challenge in the computed tomography (CT) field. Inspired by the compressive sensing theory, the sparse constraint in terms of total variation (TV) minimization has already led to promising results for low-dose CT reconstruction. Compared to the discrete gradient transform used in the TV method, dictionary learning is proven to be an effective way for sparse representation. On the other hand, it is important to consider the statistical property of projection data in the low-dose CT case. Recently, we have developed a dictionary learning based approach for low-dose X-ray CT. In this paper, we present this method in detail and evaluate it in experiments. In our method, the sparse constraint in terms of a redundant dictionary is incorporated into an objective function in a statistical iterative reconstruction framework. The dictionary can be either predetermined before an image reconstruction task or adaptively defined during the reconstruction process. An alternating minimization scheme is developed to minimize the objective function. Our approach is evaluated with low-dose X-ray projections collected in animal and human CT studies, and the improvement associated with dictionary learning is quantified relative to filtered backprojection and TV-based reconstructions. The results show that the proposed approach might produce better images with lower noise and more detailed structural features in our selected cases. However, there is no proof that this is true for all kinds of structures.

  12. First Results from the Online Radiation Dose Monitoring System in ATLAS experiment

    CERN Document Server

    Mandić, I; The ATLAS collaboration; Deliyergiyev, M; Gorišek, A; Kramberger, G; Mikuž, M; Franz, S; Hartert, J; Dawson, I; Miyagawa, P; Nicolas, L

    2011-01-01

    High radiation doses which will accumulate in components of ATLAS experiment during data taking will causes damage to detectors and readout electronics. It is therefore important to continuously monitor the doses to estimate the level of degradation caused by radiation. Online radiation monitoring system measures ionizing dose in SiO2 , displacement damage in silicon in terms of 1-MeV(Si) equivalent neutron fluence and fluence of thermal neutrons at several locations in ATLAS detector. In this paper design of the system, results of measurements and comparison of measured integrated doses and fluences with predictions from FLUKA simulation will be shown.

  13. Adult and child doses in standardised X ray examinations

    International Nuclear Information System (INIS)

    Gallini, R.E.; Belletti, S.; Berna, V.; Giugni, U.

    1992-01-01

    Data are presented on patient doses measured during standard hospital routine in seven radiological departments in the Province of Brescia. This study is part of a Quality Assurance Programme, carried out to assess the possibility and validity of a regional protocol. Before collecting dose data, tests on the performance of the X ray units and processors were performed in every department according to a Quality Control Protocol. The following examinations were considered: chest, knee, lumbar spine, pelvis, skull and barium meal. The surface entrance doses of 314 adults and 216 children were measured. The sample size for barium meal was lower: 65 adults and only 10 children. The patients anthropometric data and the technical parameters used were collected at the same time. For adults the organ doses and effective dose equivalent (EDE) were calculated. A wide range of entrance doses were obtained both for adults and children. The reasons can be: patient size, performance of the equipment and processors, film-screen combination, use of AEC, use of fluoroscopy and grid, training and skill of the staff

  14. Adult and child doses in standardised X ray examinations

    International Nuclear Information System (INIS)

    Gallini, R.E.; Belletti, S.; Berna, V.; Giugni, U.

    1992-01-01

    Data are presented on patient doses measured during standard hospital routine in seven radiological departments in the Province of Brescia, as part of a Quality Assurance Programme, carried out to assess the possibility and validity of a regional protocol. Before collecting dose data, tests on the performance of the X ray units and processors were performed in every department according to a Quality Control Protocol. The following examinations were considered: chest, knee, lumbar spine, pelvis, skull and barium meal. Surface entrance doses of 314 adults and 216 children were measured. The sample size for barium meal was lower: 65 adults and 10 children. The patients anthropometric data and technical parameters used were collected at the same time. For adults the organ doses and effective dose equivalent (EDE) were calculated. A wide range of entrance doses were obtained both for adults and children, due to patient size, performance of the equipment and processors, film-screen combination, use of AEC, use of fluoroscopy and grid, training and skill of the staff. (author)

  15. Status of eye lens radiation dose monitoring in European hospitals

    International Nuclear Information System (INIS)

    Carinou, Eleftheria; Ginjaume, Merce; O’Connor, Una; Kopec, Renata; Sans Merce, Marta

    2014-01-01

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  16. Assessment of patient doses and image quality in X-ray diagnostics in Norway

    International Nuclear Information System (INIS)

    Olerud, H.M.

    1998-01-01

    Results from other industrialized countries indicate that the annual number of diagnostic procedures approaches one for every member of the population, and in many cases the individual radiation doses are higher than from any other human activity. Furthermore, the doses to patients for the same type of examination differ widely from place to place, suggesting that there is a considerable potential for dose reduction. This motivated an investigation of the diagnostic use of X-rays in Norway. The trends in the number of X-ray examinations performed annually have been studied. The patient doses (all diagnostics) and image quality (mammography and computed tomography) have been assessed for various radiological procedures. This form the basis for the assessment of total collective effective dose (CED) from X-rays in Norway, and further risk estimates. The radiological practice has then been evaluated according to the radiation protection principles of justification and optimisation. Based on the 1993 examination frequency, the total CED was assessed to 3400 manSv (0.78 mSv/inhabitant). It is estimated that this radiation burden may cause about 100 excess cancer deaths annually. The frequency of CT examination has doubled every fifth year, and did in 1993 represent 7% of the total number of examinations and 30% of the total CED. 129 refs

  17. Assessment of patient doses and image quality in X-ray diagnostics in Norway

    Energy Technology Data Exchange (ETDEWEB)

    Olerud, H M

    1998-06-01

    Results from other industrialized countries indicate that the annual number of diagnostic procedures approaches one for every member of the population, and in many cases the individual radiation doses are higher than from any other human activity. Furthermore, the doses to patients for the same type of examination differ widely from place to place, suggesting that there is a considerable potential for dose reduction. This motivated an investigation of the diagnostic use of X-rays in Norway. The trends in the number of X-ray examinations performed annually have been studied. The patient doses (all diagnostics) and image quality (mammography and computed tomography) have been assessed for various radiological procedures. This form the basis for the assessment of total collective effective dose (CED) from X-rays in Norway, and further risk estimates. The radiological practice has then been evaluated according to the radiation protection principles of justification and optimisation. Based on the 1993 examination frequency, the total CED was assessed to 3400 manSv (0.78 mSv/inhabitant). It is estimated that this radiation burden may cause about 100 excess cancer deaths annually. The frequency of CT examination has doubled every fifth year, and did in 1993 represent 7% of the total number of examinations and 30% of the total CED. 129 refs.

  18. Radiation transport of cosmic ray nuclei in lunar material and radiation doses

    International Nuclear Information System (INIS)

    Silberberg, R.; Tsao, C.H.; Adams, J.H. Jr.; Letaw, J.R.

    1985-01-01

    The radiation environment on the lunar surface is inhospitable. The permanent settlers may work ten hours per 24-hour interval for the two-week-long lunar day on the lunar surface, or 20 percent of the total time. At moderate depths below the lunar surface (less than 200 g/sq cm) the flux of secondary neutrons exceeds considerably that in the upper atmosphere of the earth, due to cosmic-ray interactions with lunar material. The annual dose equivalent due to neutrons is about 20 or 25 rem within the upper meter of the lunar surface. The dose equivalent due to gamma rays generated by nuclear interactions near the lunar surface is only on the order of 1 percent of that due to neutrons. However, gamma-ray line emission from excited nuclei and nuclear spallation products generated by cosmic rays near the lunar surface is of considerable interest: these lines permit the partial determination of lunar composition by gamma spectroscopy. 12 references

  19. Relationship between radiation dose and changes of blood cells in medical diagnostic X-ray workers in China

    International Nuclear Information System (INIS)

    Zhao Wenzheng

    1984-01-01

    The hematological changes of 2867 cases of medical X-ray workers and 1152 cases of non-X-ray medical workers were compared. It was shown that the total number of leukocytes, the numbers of neutrophils, lymphocytes and platelets were significantly lower in X-ray workers than those in controls. However, the percentages of monocytes, eosinophils, basophils and the concentration of hemoglobin were higher in the irradiated group. the difference between the two groups was statistically significant. The degree of changes in the number of blood cells was dose-dependent. A negative correlation could be found between the changes of leukocyte and neutrophil counts and cumulative dose (<250 mGy), annual dose (<15 mGy/a) and length of service of the X-ray workers; and a positive correlation existed between the percentages of basophils, eosinophils and monocytes, and the radiation dose. The abnormality rate of blood picture in the irradiated group was higher than that in the control group. Most X-ray workers with abnormal blood picture were distributed in low-dose group. The data also showed that radiation effect on male X-ray workers was greater than that on female workers. (Author)

  20. Low dose monitoring by double implant technique in IC fabrication

    International Nuclear Information System (INIS)

    Ahmad, I.B.; Weidemann, J.

    1995-01-01

    The utilisation of low dose implant monitoring (using Boron) in a manufacturing line has been discussed. The utilisation of phosphorus ions as the second implant dose were also studied as comparison. The technique relies on the fact that the sheet resistant of doped layer will increase significantly when damaged by relatively low implant dose. The technique is very sensitive and applicable for adjusting the channel dose so that an accurate threshold voltage in MOS device could be achieved

  1. Low-dose multiple-information retrieval algorithm for X-ray grating-based imaging

    International Nuclear Information System (INIS)

    Wang Zhentian; Huang Zhifeng; Chen Zhiqiang; Zhang Li; Jiang Xiaolei; Kang Kejun; Yin Hongxia; Wang Zhenchang; Stampanoni, Marco

    2011-01-01

    The present work proposes a low dose information retrieval algorithm for X-ray grating-based multiple-information imaging (GB-MII) method, which can retrieve the attenuation, refraction and scattering information of samples by only three images. This algorithm aims at reducing the exposure time and the doses delivered to the sample. The multiple-information retrieval problem in GB-MII is solved by transforming a nonlinear equations set to a linear equations and adopting the nature of the trigonometric functions. The proposed algorithm is validated by experiments both on conventional X-ray source and synchrotron X-ray source, and compared with the traditional multiple-image-based retrieval algorithm. The experimental results show that our algorithm is comparable with the traditional retrieval algorithm and especially suitable for high Signal-to-Noise system.

  2. Development of a Compact Gamma-ray Detector for a Neural-Network Radiation Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. S.; Ha, J. H.; Lee, K. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, C. H. [Hanyang Univ., Seoul (Korea, Republic of)

    2012-03-15

    Radiation monitoring is very important to secure safety in nuclear-related facilities and against nuclear terrorism. For wide range of radiation monitoring, neutral network system of radiation detection is most efficient way. Thus, a compact radiation detector is useful to install in wide range to be concerned. A compact gamma-ray detector was fabricated by using a CsI(Tl) scintillator, which was matched with the formerly developed PIN photodiode, for a neural network radiation monitoring. At room temperature, the fabricated compact gamma-ray detector demonstrates an energy resolution of 13.3 % for 662 keV 6.9% for 1330 keV. The compactness, the low-voltage power consumption and the physical hardness are very useful features for a neural network radiation monitoring. In this study, characteristics of a fabricated compact gamma-ray detector were presented. An important aspect to consider in a neural-network radiation monitoring such as reaction probability of the fabricated compact detector for angle of incident gamma-ray was also addressed.

  3. Adaptive response of DNA strand breaks in lymphocytes to low dose and γ-rays

    International Nuclear Information System (INIS)

    Du Zeji; Su Liaoyuan; Kong Xiangrong; Tian Hailin

    1996-01-01

    Fluorometric analysis of DNA unwinding was used to study the adaptive response of DNA strand breaks induced by low dose γ-rays and the effect of pADPRT inhibitor-3-AB on the adaptive response. The results indicated that 0.5-4 cGy γ-rays could induce adaptive response of DNA strand breaks in lymphocytes, especially at the doses of 2.0 and 4.0 cGy. This response was not obvious after 8.0 cGy γ-rays irradiation. A challenge dose of 5-20 Gy could make the response expressed, 15 Gy was the best one and 30 Gy was too high to give an adaptive response . 0.5 mM 3-AB could inhibit the response vigorously. As the concentration increased, the adaptive response could be inhibited completely

  4. Assessment of pediatrics radiation dose from routine x-ray ...

    African Journals Online (AJOL)

    Background: Given the fact that children are more sensitive to ionizing radiation than adults,with an increased risk of developing radiation-induced cancer,special care should be taken when they undergo X-ray examinations. The main aim of the current study was to determine Entrance Surface Dose (ESD) to pediatric ...

  5. Effect of repeated small-dose γ-ray irradiation on atopic dermatitis in NC/Nga mice

    International Nuclear Information System (INIS)

    Fang, Su-Ping; Muto, Yasuko; Tago, Fumitoshi; Simura, Noriko; Kojima, Shuji

    2006-01-01

    We previously showed that several small-dose 0.5 Gy whole-body γ-ray irradiation inhibits tumor growth in mice via elevation of the interferon (IFN)-γ/interleukin 4 (IL-4) ratio concomitantly with a decrease in the percentage of B cells. Here, we examined whether repeated small-dose (0.5 Gy, 10 times) γ-ray irradiation influences atopic dermatitis in an NC/Nga mouse model. It was found that repeated γ-ray irradiation increased total IgE in comparison with the disease-control group. Levels of IL-4 and IL-5 were increased versus the disease-control group, while IFN-γ was slightly decreased, resulting in a further decrease of the IFN-γ/IL-4 ratio compared with the disease-control group. These results indicate that repeated small-dose γ-ray irradiation may exacerbate atopic dermatitis. This may be because the irradiation induces not helper T lymphocyte 1 (Th1), but Th2 polarization in this atopic mouse model, i.e., the effects of small-dose irradiation may be different in conditions involving immune hypersensitivity and impaired immunity. (author)

  6. Relationship between mutation frequency of GPA locus and cumulative dose among medical diagnostic X-ray workers

    International Nuclear Information System (INIS)

    Wang Jixian; Yu Wenru; Li Benxiao; Fan Tiqiang; Li Zhen; Gao Zhiwei; Chen Zhenjun; Zhao Yongcheng

    2000-01-01

    Objective: To explore the feasibility of using GPA locus mutation assay as a bio-dosimeter for occupational exposure to ionizing radiation. Methods: An improved technique of GPA locus mutation assay was used in th study. The frequencies of mutant RBC in peripheral blood of 55 medical X-ray workers and 50 controls employed in different calendar-year periods were detected. The relationship between mutation frequencies (MFs) and period of entry, working years and cumulative doses were analyzed. Results: The MFs were significantly elevated among X-ray workers employed before 1970. This finding is similar to the result of cancer epidemiological study among medical X-ray workers , in which the cancer risk was significantly increased only X-ray workers employed before 1970. The MFs of GPA increased with increasing cumulative dose. The dose-effect relationship of Nφ MF with cumulative dose was closer than that of NN MF. Conclusion: There are many problems to be solved for using GPA MF assay as a bio-dosimeter such as individual variation, specificity and calibration curve of dose-effect relationship

  7. An automated DICOM database capable of arbitrary data mining (including radiation dose indicators) for quality monitoring.

    Science.gov (United States)

    Wang, Shanshan; Pavlicek, William; Roberts, Catherine C; Langer, Steve G; Zhang, Muhong; Hu, Mengqi; Morin, Richard L; Schueler, Beth A; Wellnitz, Clinton V; Wu, Teresa

    2011-04-01

    The U.S. National Press has brought to full public discussion concerns regarding the use of medical radiation, specifically x-ray computed tomography (CT), in diagnosis. A need exists for developing methods whereby assurance is given that all diagnostic medical radiation use is properly prescribed, and all patients' radiation exposure is monitored. The "DICOM Index Tracker©" (DIT) transparently captures desired digital imaging and communications in medicine (DICOM) tags from CT, nuclear imaging equipment, and other DICOM devices across an enterprise. Its initial use is recording, monitoring, and providing automatic alerts to medical professionals of excursions beyond internally determined trigger action levels of radiation. A flexible knowledge base, aware of equipment in use, enables automatic alerts to system administrators of newly identified equipment models or software versions so that DIT can be adapted to the new equipment or software. A dosimetry module accepts mammography breast organ dose, skin air kerma values from XA modalities, exposure indices from computed radiography, etc. upon receipt. The American Association of Physicists in Medicine recommended a methodology for effective dose calculations which are performed with CT units having DICOM structured dose reports. Web interface reporting is provided for accessing the database in real-time. DIT is DICOM-compliant and, thus, is standardized for international comparisons. Automatic alerts currently in use include: email, cell phone text message, and internal pager text messaging. This system extends the utility of DICOM for standardizing the capturing and computing of radiation dose as well as other quality measures.

  8. Implementation of Ray Safe i2 System for staff dose measuring in interventional radiology

    International Nuclear Information System (INIS)

    Gershan, Vesna; Atsovska, Violeta

    2013-01-01

    Interventional radiology procedures usually delivered the highest radiation dose to the patients as well as to medical personal. Beside another factors like patient size, fluoroscopy time, machine calibration etc., a good clinical practice has strong effects to staff and patient’s radiation dose. Materials and methods: In August 2012, a Ray Safe i2 system was installed in a private hospital in Skopje. The main purpose of this dosimetry system is to provide real time indication for the current exposure level of the medical personal. Knowing that, the staff has prerequisites to adjust their behavior to minimize unnecessary exposure like changing distance from exposed volume, C-ram angulations, field of view etc. and on this way to develop a good clinical practice. The Ray Safe i2 system is consisted by ten digital dosimeters, two dock stations, real time display, dose viewer and dose manager software. During interventional procedures, each involved staff wears dosimeter which measures and records X-Ray exposure every second and transfer the data wirelessly to the real time display. Color indication bars (green, yellow, red) represents the intensity of the currently received exposure, whereas green zone indicates < 0.2 mSv/h, yellow zone from 0.2 to 2 mSv/h and red zone indications from 2 to 20 mSv/h. Additionally, accumulated dose per individual is displayed next to the color indication bars. By using the software, information about personal dose history, such as annual dose, dose per particular session, hour, day or week, can be viewed and analyzed. Results: In this work it was found that staff accumulated doses were constantly increased over time, but reported number of procedures does not correspond to this tendency. Our assumption is that there is a misleading between reported number and actual performed procedures. Doctor1 received 55 times more dose than Doctor2 and Nurse1 received 11 to 3 times more dose than another Nurses. It was found a correlation of R2

  9. Long X-ray burst monitoring with INTEGRAL

    DEFF Research Database (Denmark)

    X-ray bursts are thermonuclear explosions on the surface of accreting neutron stars in low mass X-ray binary systems. In the frame of the INTEGRAL observational Key Programme over the Galactic Center a good number of the known X-ray bursters are frequently being monitored. An international...... collaboration lead by the JEM-X team at the Danish National Space Center has proposed to exploit the improved sensitivity of the INTEGRAL instruments to investigate the observational properties and physics up to high energies of exceptional burst events lasting between a few tens of minutes and several hours....... Of special interest are low luminosity bursting sources that exhibit X-ray bursts of very different durations allowing to study the transition from a hydrogen-rich bursting regime to a pure helium regime and from helium burning to carbon burning. I will present results obtained from INTEGRAL archive data...

  10. Dose fractionation in synchrotron radiation x-ray phase micro-tomography

    International Nuclear Information System (INIS)

    Frachon, Thibaut; Weber, Loriane; Hesse, Bernhard; Rit, Simon; Dong, Pei; Olivier, Cecile; Peyrin, Françoise; Langer, Max

    2015-01-01

    Phase sensitive x-ray imaging expands the applicability of standard attenuation based techniques by offering several orders of magnitude of increase in sensitivity. Due to the short wavelength, x-ray phase is not directly measurable, but has to be put in evidence by the use of phase contrast techniques. The phase can then be reconstructed from one or several phase contrast images. In this study, we consider synchrotron x-ray phase micro-computed tomography (μCT) based on free space propagation for heterogeneous and strongly absorbing objects. This technique generally relies on acquiring several scans of the sample at different detector distances. It is also generally believed that multi-distance phase μCT needs a higher dose input than single distance phase μCT. The purpose of this work is to study the impact of different means of dose fractionation on the reconstructed image quality. We define different acquistion schemes in multi-distance in-line phase μCT. Previously, the exposure time at each sample-to-detector distance was usually kept the same. Here, we let not only the number of distances vary but also the fraction of exposure time at each distance, the total exposure time being kept constant. Phase retrieval is performed with the mixed approach algorithm. The reconstructed μCT images are compared in terms of accuracy, precision and resolution. In addition, we also compare the result of dose fractionated multi distance phase μCT to single distance phase μCT using the same total radiation dose. In the multi-distance approach, we find that using different exposure times on each distance improves the image quality in the reconstructed image. Further, we show that, despite having the same total dose delivery, the multi distance imaging method gives better image quality than the single distance method, at the cost of an additional overhead from camera displacements and reference images. We show that by optimizing the acquistion parameters in terms of

  11. Monitoring and Analysis of Environmental Gamma Dose Rate around Serpong Nuclear Complex

    Directory of Open Access Journals (Sweden)

    I.P. Susila

    2017-08-01

    Full Text Available An environmental radiation monitoring system that continuously measures gamma dose rate around nuclear facilities is an important tool to present dose rate information to the public or authorities for radiological protection during both normal operation and radiological accidents. We have developed such a system that consists of six GM-based device for monitoring the environmental dose rate around Serpong Nuclear Complex. It has operated since 2010. In this study, a description of the system and analysis of measured data are presented. Analysis of the data for the last five years shows that the average dose rate levels were between 84-99 nSv/h which are still lower than terrestrial gamma radiation levels at several other locations in Indonesia. Time series analysis of the monitoring data demonstrates a good agreement between an increase in environmental gamma dose rate and the presence of iodine and argon in the air by in situ measurement. This result indicates that system is also effective for an early warning system in the case of radiological emergency.

  12. Health risk assessment of doses to patients\\' eyes from dental X-ray ...

    African Journals Online (AJOL)

    The skin entry dose to patients\\' eyes during dental x-ray examination was carried out on one hundred and ten patients comprising infants and adult of both sexes. The dose measurements was performed at Alpha dental centre, Ibadan, using Lithium fluoride thermoluminiscent dosimeters (TLD). The results of the study ...

  13. Low-Dose X-ray CT Reconstruction via Dictionary Learning

    Science.gov (United States)

    Xu, Qiong; Zhang, Lei; Hsieh, Jiang; Wang, Ge

    2013-01-01

    Although diagnostic medical imaging provides enormous benefits in the early detection and accuracy diagnosis of various diseases, there are growing concerns on the potential side effect of radiation induced genetic, cancerous and other diseases. How to reduce radiation dose while maintaining the diagnostic performance is a major challenge in the computed tomography (CT) field. Inspired by the compressive sensing theory, the sparse constraint in terms of total variation (TV) minimization has already led to promising results for low-dose CT reconstruction. Compared to the discrete gradient transform used in the TV method, dictionary learning is proven to be an effective way for sparse representation. On the other hand, it is important to consider the statistical property of projection data in the low-dose CT case. Recently, we have developed a dictionary learning based approach for low-dose X-ray CT. In this paper, we present this method in detail and evaluate it in experiments. In our method, the sparse constraint in terms of a redundant dictionary is incorporated into an objective function in a statistical iterative reconstruction framework. The dictionary can be either predetermined before an image reconstruction task or adaptively defined during the reconstruction process. An alternating minimization scheme is developed to minimize the objective function. Our approach is evaluated with low-dose X-ray projections collected in animal and human CT studies, and the improvement associated with dictionary learning is quantified relative to filtered backprojection and TV-based reconstructions. The results show that the proposed approach might produce better images with lower noise and more detailed structural features in our selected cases. However, there is no proof that this is true for all kinds of structures. PMID:22542666

  14. Monitoring and radiation dose estimation for internal contamination of occupational workers

    Energy Technology Data Exchange (ETDEWEB)

    Kol, R; Laichter, Y [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1996-12-01

    The assessment of interval radiation doses due to intake of radionuclides differs totally from external dosimetry. External dosimetry is relatively straight forward: Workers are equipped with appropriate dosimeters that give the dose upon direct reading. Internal dosimetry is actually an assessment of the dose based on results of personnel and environmental monitoring (authors).

  15. A real-time stack radioactivity monitoring system and dose projection program

    Energy Technology Data Exchange (ETDEWEB)

    Hull, A.P.; Michael, P.A. [Brookhaven National Laboratory, Upton, NY (United States); Bernstein, H.J. [Bernstein & Sons, Bellport, NY (United States)

    1995-02-01

    At Brookhaven National Laboratory, a commercial Low- and High-Range Air Effluent Monitor has become operational at the 60 Mw (t) High Flux Beam Reactor. Its output data is combined with that from ground-level and elevated meteorological sensors to provide a real-time projection of the down-wind dose rates from noble gases and radioiodines released from the HFBR`s 100 m stack. The output of the monitor, and the meteorological sensors and the dose projections can be viewed at emergency response terminals located in the Reactor Control Room, its Technical Support Center and at the laboratory`s separately located Meteorological Station and Monitoring and Assessment Center.

  16. Scatter and transmission doses from several pediatric X-ray examinations in a nursery

    International Nuclear Information System (INIS)

    Burrage, John W.; Rampant, Peter L.; Beeson, Brendan P.

    2003-01-01

    While several studies have investigated the dose from scattered radiation from X-ray procedures in a pediatric nursery, they examined scatter from chest procedures only, or the types of examination were not specified. The aim of this study was to collect scatter and transmission data from several types of X-ray examinations. Using a ''newborn'' anthropomorphic phantom and an ion chamber, a series of scatter and transmission dose measurements were performed using typical exposure factors for chest, chest and abdomen, skull, skeletal long bone and spine procedures. The phantom was inside a crib for all exposures. The maximum scatter dose measured at 1 m from the field center was about 0.05 μGy per exposure for lateral skulls. Transmission doses for lateral exams were around 0.1 μGy per exposure at 1 m from the isocenter. The study demonstrated that scatter dose to other patients in a neonatal unit is not significant, assuming the distance between adjacent cribs is in the order of 1 m. Transmission doses are also low provided the beam is fully intercepted by the cassette. For an average workload the dose received by imaging technologists would be small. (orig.)

  17. Dose in conventional radiography

    International Nuclear Information System (INIS)

    Acuna D, E.; Padilla R, Z. P.; Escareno J, E.; Vega C, H. R.

    2011-10-01

    It has been pointed out that medical exposures are the most significant sources of exposure to ionizing radiation for the general population. Inside the medical exposures the most important is the X-ray use for diagnosis, which is by far the largest contribution to the average dose received by the population. From all studies performed in radiology the chest radiography is the most abundant. In an X-ray machine, voltage and current are combined to obtain a good image and a reduce dose, however due to the workload in a radiology service individual dose is not monitored. In order to evaluate the dose due to chest radiography in this work a plate phantom was built according to the ISO recommendations using methylmethacrylate walls and water. The phantom was used in the Imaging department of the Zacatecas General Hospital as a radiology patient asking for a chest study; using thermoluminescent dosimeters, TLD 100 the kerma at the surface entrance was determined. (Author)

  18. Commentary: progress in optimization of patient dose and image quality in x-ray diagnostics

    International Nuclear Information System (INIS)

    Carlsson, G.A.; Chan, H.-P.

    1999-01-01

    X-ray diagnostics gives the largest contribution to the population dose from man-made radiation sources. Strategies for reduction of patient doses without loss of diagnostic accuracy are therefore of great interest to society and have been focussed in general terms by the ICRP (ICRP 1996) through the introduction of the concept of diagnostic reference levels. The European Union has stimulated research in the field, and, based on patient dose measurements and radiologists' appreciation of acceptable image quality, good radiographic techniques have been identified and recommended (EUR 1996a, b) for conventional screen-film imaging. These efforts have resulted in notable dose reductions in clinical practices (Hart et al 1996). In spite of 100 years of use of x-rays for diagnostics, the choice of technique parameters still relies to a great extent on experience. Scientific efforts to optimize the choice in terms of finding the parameter settings which yield sufficient image quality at the lowest possible cost in dose are still rare. True optimization requires (1) estimation of the image quality needed to make a correct diagnosis and (2) methods to investigate all possible means of achieving this image quality in order to be able to decide which of them gives the lowest dose. The paper by Tapiovaara, Sandborg and Dance published in this issue of Physics in Medicine and Biology (pages 537-559) addresses the optimization of paediatric fluoroscopy, a timely and important topic. Fluoroscopy procedures, used to guide x-ray examinations or interventional procedures, are little standardized and may result in high dose levels; radiation exposure in childhood is likely to result in a higher lifetime risk than the same exposure later in life. The authors represent an interesting mix of expertise within various scientific fields: the theory of medical imaging and assessment of image quality, the physics of diagnostic radiology and radiation dosimetry. They provide good insights

  19. The development of remote wireless radiation dose monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin-woo [KAERI - Korea Atomic Energy Research Institute, Jeongup-si (Korea, Republic of); Chonbuk National University, Jeonjoo-Si (Korea, Republic of); Jeong, Kyu-hwan [KINS - Korea Institute of Nuclear Safety, Daejeon-Si (Korea, Republic of); Kim, Jong-il [Chonbuk National University, Jeonjoo-Si (Korea, Republic of); Im, Chae-wan [REMTECH, Seoul-Si (Korea, Republic of)

    2015-07-01

    Internet of things (IoT) technology has recently shown a large flow of IT trends in human life. In particular, our lives are now becoming integrated with a lot of items around the 'smart-phone' with IoT, including Bluetooth, Near Field Communication (NFC), Beacons, WiFi, and Global Positioning System (GPS). Our project focuses on the interconnection of radiation dosimetry and IoT technology. The radiation workers at a nuclear facility should hold personal dosimeters such as a Thermo-Luminescence Dosimeter (TLD), an Optically Stimulated Luminescence Dosimeter (OSL), pocket ionization chamber dosimeters, an Electronic Personal Dosimeter (EPD), or an alarm dosimeter on their body. Some of them have functions that generate audible or visible alarms to radiation workers in a real working area. However, such devices used in radiation fields these days have no functions for communicating with other areas or the responsible personnel in real time. In particular, when conducting a particular task in a high dose area, or a number of repair works within a radiation field, radiation dose monitoring is important for the health of the workers and the work efficiency. Our project aims at the development of a remote wireless radiation dose monitoring system (RWRD) that can be used to monitor the radiation dose in a nuclear facility for radiation workers and a radiation protection program In this project, a radiation dosimeter is the detection device for personal radiation dose, a smart phone is the mobile wireless communication tool, and, Beacon is the wireless starter for the detection, communication, and position of the worker using BLE (Bluetooth Low Energy). In this report, we report the design of the RWRD and a demonstration case in a real radiation field. (authors)

  20. The development of remote wireless radiation dose monitoring system

    International Nuclear Information System (INIS)

    Lee, Jin-woo; Jeong, Kyu-hwan; Kim, Jong-il; Im, Chae-wan

    2015-01-01

    Internet of things (IoT) technology has recently shown a large flow of IT trends in human life. In particular, our lives are now becoming integrated with a lot of items around the 'smart-phone' with IoT, including Bluetooth, Near Field Communication (NFC), Beacons, WiFi, and Global Positioning System (GPS). Our project focuses on the interconnection of radiation dosimetry and IoT technology. The radiation workers at a nuclear facility should hold personal dosimeters such as a Thermo-Luminescence Dosimeter (TLD), an Optically Stimulated Luminescence Dosimeter (OSL), pocket ionization chamber dosimeters, an Electronic Personal Dosimeter (EPD), or an alarm dosimeter on their body. Some of them have functions that generate audible or visible alarms to radiation workers in a real working area. However, such devices used in radiation fields these days have no functions for communicating with other areas or the responsible personnel in real time. In particular, when conducting a particular task in a high dose area, or a number of repair works within a radiation field, radiation dose monitoring is important for the health of the workers and the work efficiency. Our project aims at the development of a remote wireless radiation dose monitoring system (RWRD) that can be used to monitor the radiation dose in a nuclear facility for radiation workers and a radiation protection program In this project, a radiation dosimeter is the detection device for personal radiation dose, a smart phone is the mobile wireless communication tool, and, Beacon is the wireless starter for the detection, communication, and position of the worker using BLE (Bluetooth Low Energy). In this report, we report the design of the RWRD and a demonstration case in a real radiation field. (authors)

  1. Suitable gamma ray dose determination in order to induce genetic variation in kaboli chickpea (Cicer Arietinum L)

    International Nuclear Information System (INIS)

    Naserian Khiabani, B.; Ahari Mostafavi, H.; Fathollahi, H.; Vedadi, S.; Mosavi Shalmani, M. A.

    2008-01-01

    In spite of chickpea's use in Iran and its ability of being replaced to adjust the shortage of protein in dietary habits, yield production is very low. One of the main reasons for chickpea's low yield production is its sensitiveness to some diseases, pest and environmental stresses. Genetic variation in chickpea is very low, because of its self pollination. In breeding programs, genetic variation plays an essential role so that the induction of genetic variation in plant population is very important for the plant breeders. The induced mutation through different kinds of mutagens is one of the important ways of genetic variation. In this research, first the sensitiveness of four cultivars (ILC.486, Philip86, Bivinich, Jam) were assessed to different gamma ray doses (100, 200, 300, 400 Gy). The results showed that with an increase in gamma ray dose, the growth rate of chickpea's genotypes decreases. In this respect, the decrease of growth rate has a linear relationship with the gamma ray dose and it is independent from the genotypes. The root length is more sensitive to gamma ray doses than its shoot, and it was observed that at the low doses the root growth decreases, comparing to the shoot growth. On the other hand, in high doses of gamma ray growth abrasion (Ageotropism, Albinism and etc.) were observed. Some traits variation (such as leaf shape, leaf size, leaf color, Albinism, etc.) were seen in M 2 generation, and finally to continue the project, three doses of gamma ray (150,200,250) were selected for the next year

  2. First Results from the Online Radiation Dose Monitoring System in ATLAS experiment

    CERN Document Server

    Mandić, I; The ATLAS collaboration; Deliyergiyev, M; Gorišek, A; Kramberger, G; Mikuž, M; Franz, S; Hartert, J; Dawson, I; Miyagawa, P S; Nicolas, L

    2011-01-01

    High radiation doses which will accumulate in components of ATLAS experiment during data taking will cause damage to detectors and readout electronics. It is therefore important to continuously monitor the doses to estimate the level of degradation caused by radiation. Online radiation monitoring system measures ionizing dose in SiO2 and fluences of 1-MeV(Si) equivalent neutrons and thermal neutrons at several locations in ATLAS detector. In this paper measurements collected during two years of ATLAS data taking are presented and compared to predictions from radiation background simulations.

  3. Very low dose and dose-rate X-ray induced adaptive response in human lymphocytes at various cell cycle stages against bleomycin induced chromatid aberrations

    International Nuclear Information System (INIS)

    Hossein Mozdarani; Moghadam, R.N.

    2007-01-01

    Complete text of publication follows. Objective: To study the adaptive response induced by very low doses of X-rays at very low dose rate in human lymphocytes at different cell cycle stages followed by a challenge dose of bleomycin sulphate at G2 phase. Materials and Methods: Human peripheral blood lymphocytes before (G0) and after PHA stimulation (G1 and G2) were exposed to 1 and 5 cGy X-rays generated by a fluoroscopy unit with a dose rate of 5.56 mGy/min and challenged with 5 μg/ml bleomycin sulphate (BLM) 48 hours after culture initiation. Mitotic cells were arrested at metaphase by addition of colcemid in cultures 1.5 h before harvesting. Harvesting and slide preparation was performed using standard method. 100 well spread metaphases were analyzed for the presence of chromatid type aberrations for each sample. Results: Results obtained indicate that there is a linear relationship between the dose of BLM and chromatid aberrations below 5 μg/ml (R=0.93, p<0.0001). The results also show that pretreatment of lymphocytes with low dose X-rays at G0, G1 and G2 phases of the cell cycle significantly reduced the sensitivity of lymphocytes to the clastogenic effects of BLM in G2. Much lower frequencies of chromatid aberrations were observed in X-ray irradiated lymphocytes following BLM treatment (p<0.05). The magnitudes of adaptation induced at different phases of the cell cycle were not significantly different. Furthermore, there was no a significant difference in the magnitude of adaptive response induced by either 1 or 5 cGy X-rays. Conclusion: These observations might indicate that resistance of pre-exposure of lymphocytes to very low doses of X-rays protects them from clastogenic effects of BLM. This effect might be due to initial DNA damage induced in these cells leading to provocation of an active DNA repair mechanism independent of cell cycle stage.

  4. Use of a solar panel as a directionally sensitive large-area radiation monitor for direct and scattered x-rays and gamma-rays.

    Science.gov (United States)

    Abdul-Majid, S

    1987-01-01

    The characteristics of a 25.4 X 91 cm solar cell panel used as an x-ray and gamma-ray radiation monitor are presented. Applications for monitoring the primary x-ray beam are described at different values of operating currents and voltages as well as for directional dependence of scattered radiation. Other applications in gamma-ray radiography are also given. The detector showed linear response to both x-ray and gamma-ray exposures. The equipment is rigid, easy to use, relatively inexpensive and requires no power supply or any complex electronic equipment.

  5. Low dose X –ray effects on catalase activity in animal tissue

    International Nuclear Information System (INIS)

    Focea, R; Nadejde, C; Creanga, D; Luchian, T

    2012-01-01

    This study was intended to investigate the effect of low-dose X ray-irradiation upon the activity of catalase (CAT) in freshly excised chicken tissues (liver, kidney, brain, muscle). The tissue samples were irradiated with 0.5Gy and 2Gy respectively, in a 6 MV photon beam produced by a clinical linear accelerator (VARIAN CLINAC 2100SC). The dose rate was of 260.88cGy/min. at 100 cm source to sample distance. The catalase level was assayed spectrophotometrically, based on reaction kinetics, using a catalase UV assay kit (SIGMA). Catalase increased activity in various tissue samples exposed to the studied X ray doses (for example with 24 % in the liver cells, p<0.05) suggested the stimulation of the antioxidant enzyme biosynthesis within several hours after exposure at doses of 0.5 Gy and 2 Gy; the putative enzyme inactivation could also occur (due to the injuries on the hydrogen bonds that ensure the specificity of CAT active site) but the resulted balance of the two concurrent processes indicates the cell ability of decomposing the hydrogen peroxide-with benefits for the cell physiology restoration for the chosen low dose radiation.

  6. Antipsychotic treatment dosing profile in patients with schizophrenia evaluated with electronic monitoring (MEMS®).

    Science.gov (United States)

    Acosta, Francisco J; Ramallo-Fariña, Yolanda; Bosch, Esperanza; Mayans, Teresa; Rodríguez, Carlos J; Caravaca, Ana

    2013-05-01

    Although the Medication Event Monitoring System (MEMS®) device offers accurate information on treatment dosing profile, such profile has never been studied in patients with schizophrenia. Enhancing our knowledge on this issue would help in developing intervention strategies to improve adherence to antipsychotic treatment in these patients. 74 outpatients with schizophrenia were monitored with the MEMS device for a 3-month period, for evaluation of antipsychotic treatment dosing profile, possible influence of medication schedule-related variables, adherence to treatment--considering dose intake within prescribed timeframes--and possible Hawthorne's effect of using the MEMS device. Dose-omission gaps occurred in 18.7% of monitoring days, most frequently during weekends, almost significantly. Almost one-third of prescribed doses were taken out of prescribed time. Neither the prescribed number of daily doses nor the indicated time of the day for dose intake (breakfast, dinner), were associated with correct antipsychotic dosing. Excess-dose was rare in general, and more frequent out of prescribed dose timeframe. No Hawthorne's effect was found for the MEMS device. Adherence reached only 35% according to a definition that included dose intake within prescribed timeframes. Antipsychotic treatment dosing was considerably irregular among patients with schizophrenia. Strategies to reduce dose-omission gaps and increase dosing within prescribed timeframes seem to be necessary. Gaining knowledge on precise oral antipsychotic dosing profiles or the influence of schedule-related variables may be useful to design strategies towards enhancing adherence. There appears to be no Hawthorne's effect associated with the use of MEMS devices in outpatients with schizophrenia. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Skin Entrance dose to patients from routine P-A chest X-ray ...

    African Journals Online (AJOL)

    Background: Radiation of any amount is potentially hazardous and it should be minimized as much as possible during health care delivery. Objective: To determine and assess the variation of the dose received by patients undergoing chest x-ray examination, and to provide a useful baseline data to evaluate the dose to the ...

  8. Patient size and x-ray technique factors in head computed tomography examinations. I. Radiation doses

    International Nuclear Information System (INIS)

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

    2004-01-01

    We investigated how patient age, size and composition, together with the choice of x-ray technique factors, affect radiation doses in head computed tomography (CT) examinations. Head size dimensions, cross-sectional areas, and mean Hounsfield unit (HU) values were obtained from head CT images of 127 patients. For radiation dosimetry purposes patients were modeled as uniform cylinders of water. Dose computations were performed for 18x7 mm sections, scanned at a constant 340 mAs, for x-ray tube voltages ranging from 80 to 140 kV. Values of mean section dose, energy imparted, and effective dose were computed for patients ranging from the newborn to adults. There was a rapid growth of head size over the first two years, followed by a more modest increase of head size until the age of 18 or so. Newborns have a mean HU value of about 50 that monotonically increases with age over the first two decades of life. Average adult A-P and lateral dimensions were 186±8 mm and 147±8 mm, respectively, with an average HU value of 209±40. An infant head was found to be equivalent to a water cylinder with a radius of ∼60 mm, whereas an adult head had an equivalent radius 50% greater. Adult males head dimensions are about 5% larger than for females, and their average x-ray attenuation is ∼20 HU greater. For adult examinations performed at 120 kV, typical values were 32 mGy for the mean section dose, 105 mJ for the total energy imparted, and 0.64 mSv for the effective dose. Increasing the x-ray tube voltage from 80 to 140 kV increases patient doses by about a factor of 5. For the same technique factors, mean section doses in infants are 35% higher than in adults. Energy imparted for adults is 50% higher than for infants, but infant effective doses are four times higher than for adults. CT doses need to take into account patient age, head size, and composition as well as the selected x-ray technique factors

  9. Toward an organ based dose prescription method for the improved accuracy of murine dose in orthovoltage x-ray irradiators

    International Nuclear Information System (INIS)

    Belley, Matthew D.; Wang, Chu; Nguyen, Giao; Gunasingha, Rathnayaka; Chao, Nelson J.; Chen, Benny J.; Dewhirst, Mark W.; Yoshizumi, Terry T.

    2014-01-01

    Purpose: Accurate dosimetry is essential when irradiating mice to ensure that functional and molecular endpoints are well understood for the radiation dose delivered. Conventional methods of prescribing dose in mice involve the use of a single dose rate measurement and assume a uniform average dose throughout all organs of the entire mouse. Here, the authors report the individual average organ dose values for the irradiation of a 12, 23, and 33 g mouse on a 320 kVp x-ray irradiator and calculate the resulting error from using conventional dose prescription methods. Methods: Organ doses were simulated in the Geant4 application for tomographic emission toolkit using the MOBY mouse whole-body phantom. Dosimetry was performed for three beams utilizing filters A (1.65 mm Al), B (2.0 mm Al), and C (0.1 mm Cu + 2.5 mm Al), respectively. In addition, simulated x-ray spectra were validated with physical half-value layer measurements. Results: Average doses in soft-tissue organs were found to vary by as much as 23%–32% depending on the filter. Compared to filters A and B, filter C provided the hardest beam and had the lowest variation in soft-tissue average organ doses across all mouse sizes, with a difference of 23% for the median mouse size of 23 g. Conclusions: This work suggests a new dose prescription method in small animal dosimetry: it presents a departure from the conventional approach of assigninga single dose value for irradiation of mice to a more comprehensive approach of characterizing individual organ doses to minimize the error and uncertainty. In human radiation therapy, clinical treatment planning establishes the target dose as well as the dose distribution, however, this has generally not been done in small animal research. These results suggest that organ dose errors will be minimized by calibrating the dose rates for all filters, and using different dose rates for different organs

  10. Pediatric radiation dose management in digital radiography

    International Nuclear Information System (INIS)

    Neitzel, U.

    2004-01-01

    Direct digital radiography (DR) systems based on flat-panel detectors offer improved dose management in pediatric radiography. Integration of X-ray generation and detection in one computer-controlled system provides better control and monitoring

  11. Determination of Doses for X-Ray Examinations of Paranasal Sinuses of Children

    International Nuclear Information System (INIS)

    Milkovic, D.; Miljanic, S.; Knezevic, Z.; Ranogajec-Komor, M.; Beck, N; Zagar, I.

    2013-01-01

    The knowledge of the absorbed doses during X-ray examination is very important, especially in paediatric radiology in order to improve radiation protection. In childhood, the paranasal sinuses diseases are very frequent and the development of sinuses has some specialities which has to be taken into consideration in X-ray diagnostics. The aim of this work was the determination of the relative doses on the thyroid gland and eyes, in respect to the entrance dose on the anthropomorphic child phantom (CIRS). The entrance doses on the phantom to the entrance dose on patients of similar age. Simultaneously the influence of human working method was studied, i.e. the performance of the radiological technicians. The age of the patients varied from 7 to 15 years, the child phantom was equivalent to 10 years age. A protective lead apron on the necks of both children and phantom was used. Doses were measured with radiophotoluminescence (RPL) and thermoluminescence (TL) dosemeters. The mean doses on the thyroid and the eyes measured in the phantom after 10 expositions were 0.20 ± 0.05 mSv, and 0.32 ± 0.02 mSv, respectively. Relative doses were calculated in relation to entrance dose of 9.96 mSv for 10 exposures, and the results were 0.02 and 0.03 for the thyroid gland and the eyes, respectively. The dosimetry results on 45 patients showed that there was a good correlation between measured doses and the body mass index (BMI). The mean entrance dose measured on the 45 patients was 0.97 ± 0.08 mSv.(author)

  12. Low Dose X-Ray Speckle Visibility Spectroscopy Reveals Nanoscale Dynamics in Radiation Sensitive Ionic Liquids

    Science.gov (United States)

    Verwohlt, Jan; Reiser, Mario; Randolph, Lisa; Matic, Aleksandar; Medina, Luis Aguilera; Madsen, Anders; Sprung, Michael; Zozulya, Alexey; Gutt, Christian

    2018-04-01

    X-ray radiation damage provides a serious bottleneck for investigating microsecond to second dynamics on nanometer length scales employing x-ray photon correlation spectroscopy. This limitation hinders the investigation of real time dynamics in most soft matter and biological materials which can tolerate only x-ray doses of kGy and below. Here, we show that this bottleneck can be overcome by low dose x-ray speckle visibility spectroscopy. Employing x-ray doses of 22-438 kGy and analyzing the sparse speckle pattern of count rates as low as 6.7 ×10-3 per pixel, we follow the slow nanoscale dynamics of an ionic liquid (IL) at the glass transition. At the prepeak of nanoscale order in the IL, we observe complex dynamics upon approaching the glass transition temperature TG with a freezing in of the alpha relaxation and a multitude of millisecond local relaxations existing well below TG . We identify this fast relaxation as being responsible for the increasing development of nanoscale order observed in ILs at temperatures below TG .

  13. Using thermoluminescence dosimetry (TLD) to determine the gonadal dose of patients under-going chest X-ray examinations at NKST hospital, Mkar

    International Nuclear Information System (INIS)

    Agba, E.H.; Akaagerger, N.B.; Kungur, S.T.

    2011-01-01

    The doses absorbed by the gonads of patients undergoing chest X-ray examinations at NKST Christian Hospital, Mkar was determined using the Thermoluminescence Dosimetry Technique of measurement. Also, the direct X-ray dose to the chest of patients undergoing the routine examinations was also determined using the Thermolumnescence Dosimetry technique of measurement. The mean gonadal dose and the X-ray dose to the patients were found to be 0.03±0.02μSv and 0.04±0.03mSv respectively after exposure. These X-ray doses to the patients is seen to be within the acceptable recommended X -ray dose limits of 1mGy recommended by ICRP.

  14. Method for reducing x-ray background signals from insertion device x-ray beam position monitors

    Directory of Open Access Journals (Sweden)

    Glenn Decker

    1999-11-01

    Full Text Available A method is described that provides a solution to the long-standing problem of stray radiation-induced signals on photoemission-based x-ray beam position monitors (BPMs located on insertion device x-ray beam lines. The method involves the introduction of a chicane into the accelerator lattice that directs unwanted x radiation away from the photosensitive x-ray BPM blades. This technique has been implemented at the Advanced Photon Source, and experimental confirmation of the technique is provided.

  15. Development of dose monitoring system applicable to various radiations with wide energy ranges

    International Nuclear Information System (INIS)

    Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira

    2006-01-01

    A new radiation dose monitor, designated as DARWIN (Dose monitoring system Applicable to various Radiations with WIde energy raNges), has been developed for real-time monitoring of doses in workspaces and surrounding environments of high energy accelerator facilities. DARWIN is composed of a phoswitch-type scintillation detector, which consists of liquid organic scintillator BC501A coupled with ZnS(Ag) scintillation sheets doped with 6 Li, and a data acquisition system based on a Digital-Storage-Oscilloscope. DARWIN has the following features: (1) capable of monitoring doses from neutrons, photons and muons with energies from thermal energy to 1 GeV, 150 keV to 100 MeV, and 1 MeV to 100 GeV, respectively, (2) highly sensitive with precision, and (3) easy to operate with a simple graphical user-interface. The performance of DARWIN was examined experimentally in several radiation fields. The results of the experiments indicated the accuracy and rapid response of DARWIN for measuring dose rates from neutrons, photons and muons with wide energies. With these properties, we conclude that DARWIN will be able to play a very important role for improving radiation safety in high energy accelerator facilities. (author)

  16. JEM-X: Joint European X-ray monitor

    DEFF Research Database (Denmark)

    Lund, Niels; Westergaard, Niels Jørgen Stenfeldt; Budtz-Jørgensen, Carl

    1998-01-01

    JEM-X is the X-ray monitor for INTEGRAL. It is being built by a large European consortium led by the Danish Space Research Institute. It consists of two identical, independent coded mask X-ray telescopes with an energy span from 3 keV to 60 keV. Each system has a microstrip gas detector and a mask...... with a 25% transparent hexagonal uniformly redundant pattern based on a bi-quadratic residue set situated 3.4 m above the detector. The fully illuminated field-of-view is circular and 4.8 degrees across. The mechanical properties and source detection sensitivities are reviewed....

  17. Prompt Gamma Ray Spectroscopy for process monitoring

    International Nuclear Information System (INIS)

    Zoller, W.H.; Holmes, J.L.

    1991-01-01

    Prompt Gamma Ray Spectroscopy (PGRS) is a very powerful analytical technique able to measure many metallic, contamination problem elements. The technique involves measurement of gamma rays that are emitted by nuclei upon capturing a neutron. This method is sensitive not only to the target element but also to the particular isotope of that element. PGRS is capable of measuring dissolved metal ions in a flowing system. In the field, isotopic neutron sources are used to produce the desired neutron flux ( 252 Cf can produce neutron flux of the order of 10 8 neutrons/cm 2 --sec.). Due to high penetrating power of gamma radiation, high efficiency gamma ray detectors can be placed in an appropriate geometry to maximize sensitivity, providing real-time monitoring with low detection level capabilities

  18. The Fermi Gamma-ray Burst Monitor Instrument

    International Nuclear Information System (INIS)

    Bhat, P. N.; Briggs, M. S.; Connaughton, V.; Paciesas, W. S.; Preece, R. D.; Meegan, C. A.; Lichti, G. G.; Diehl, R.; Greiner, J.; Kienlin, A. von; Fishman, G. J.; Kouveliotou, C.; Kippen, R. M.

    2009-01-01

    The Fermi Gamma-ray Space Telescope launched on June 11, 2008 carries two experiments onboard--the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The primary mission of the GBM instrument is to support the LAT in observing γ-ray bursts (GRBs) by providing low-energy measurements with high temporal and spectral resolution as well as rapid burst locations over a large field-of-view (≥8 sr). The GBM will complement the LAT measurements by observing GRBs in the energy range 8 keV to 40 MeV, the region of the spectral turnover in most GRBs. The GBM detector signals are processed by the onboard digital processing unit (DPU). We describe some of the hardware features of the DPU and its expected limitations during intense triggers.

  19. Dose distribution in head and neck during dental x-ray procedures

    International Nuclear Information System (INIS)

    Mason, E.W.; Goepp, R.A.

    1978-01-01

    Previous studies, notably by Franklin (Angle Ortho., 43:53-64, 1973), have shown significant exposures during cephalometric dental procedures and ways in which these exposures can be reduced. Skin dose over thyroid tissue has been measured by Alcox (J. Am. Dent. Assoc., 88:568-579, 1974), and others. This study is an expansion of thyroid dose measurements by Block, Goepp, and Mason (Angle Ortho., 47:17-24, 1977). The internal dose distribution in the head and neck area due to cephalometric and panoramic dental x-ray procedures is shown along with the dependence of orbit and thyroid dose on patient positioning. Higher doses can be delivered to deep tissue by panoramic machines since tissue at the axis of rotation is exposed during the entire procedure. (author)

  20. Life span and tumorigenesis in mice exposed to continuous low dose-rate gamma-rays

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Braga-Tanaka III, Ignacia; Takabatake, Takashi; Ichinohe, Kazuaki; Tanaka, Kimio; Matsumoto, Tsuneya; Sato, Fumiaki

    2004-01-01

    Two experiments were conducted to evaluate late biological effects of chronic low dose-rate radiation. 1: Late effects of chronic low dose-rate gamma-ray irradiation on SPF mice, using life span and pathological changes as parameters. Continuous irradiation for approximately 400 days was performed using 137 Cs gamma-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until their natural death. Statistical analyses show that the life spans of the both sexes irradiated at 20 mGy/day (p<0.0001) and of females irradiated at 1 mGy/day (p<0.05) were significantly shorter than those of the control group. There was no evidence of lengthened life span in mice continuously exposed to very low dose-rates of gama-rays. Pathodological examinations showed that the most frequently observed lethal neoplasms in males were malignant lymphomas, liver, lung, and soft tissue neoplasms, whereas, in females, malignant lymphomas and soft tissue neoplasms were common. No significant difference in the causes of death and mortality rates between groups. Hematopoietic neoplasms (malignant lymphoma and myeloid leukemia), liver, lung and soft tissue neoplasms, showed a tendency to appear at a younger age in both sexes irradiated at 20 mGy/day. Experiment 2: effects on the progeny of chronic low dose-rate gamma-ray irradiated SPF mice: preliminary study. No significant difference was observed between non-irradiated group and irradiated group with regards to litter size, sex ratio and causes of death in F1 and F2 mice. (author)

  1. Contrast monitoring techniques in CT pulmonary angiography: An important and underappreciated contributor to breast dose

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, D.P., E-mail: dpmmitchell@gmail.com; Rowan, M., E-mail: mrowan@mater.ie; Loughman, E., E-mail: eloughman@mater.ie; Ridge, C.A., E-mail: cridge@mater.ie; MacMahon, P.J., E-mail: pmacmahon@mater.ie

    2017-01-15

    Objective: The aims of our study were to evaluate the contribution of contrast-monitoring techniques to breast dose in pregnant and non-pregnant women, and to investigate the effect of a reduced peak kilovoltage (kV) monitoring scan protocol on breast dose and Computed Tomography Pulmonary Angiography (CTPA) diagnostic quality. Materials and methods: Single center retrospective study of 221 female patients undergoing a reduced kV 80 kV contrast-monitoring CTPA protocol compared to 281 patients using the conventional 120 kV contrast-monitoring protocol (Siemens Somatom Definition AS + ). 99 pregnant patients analyzed separately. ImPACT dosimetry software was used to calculate dose. Group subsets were evaluated to assess CTPA diagnostic quality. Results: The contrast-monitoring component of a CTPA study constituted 27% of the overall breast dose when using a standard 120 kV protocol compared to only 7% of the overall breast dose in the 80 kV study group. The dose to the breast from the contrast-monitoring component alone was reduced by 79% in the non-pregnant patients (0.36mGy ± 0.37 versus 1.7mGy ± 1.02; p < 0.001), and by 88% in the pregnant population (0.25 mGy ± 0.67 versus 2.24mGy ± 1.61; p < 0.001). There was no statistical difference in CTPA diagnostic quality or timing. Conclusion: Despite a short scan length and relatively small DLP, contrast-monitoring techniques (test-bolus or bolus-tracked) set at 120 kV can account for 27% of the overall breast dose accrued from a CTPA study. By decreasing the kilovoltage of the contrast-monitoring component, a significant reduction in breast dose for pregnant and non-pregnant female patients can be achieved without affecting CTPA quality or timing.

  2. Monte Carlo method for dose calculation due to oral X-rays

    International Nuclear Information System (INIS)

    Loureiro, Eduardo Cesar de Miranda

    1998-06-01

    The increasing utilization of oral X-rays, especially in youngsters and children, calls for the assessment of equivalent doses in their organs and tissues. With this purpose, a Monte Carlo code was adapted to simulate an X-ray source irradiating phantoms of the MIRD-5 type with different ages (10, 15 and 40 years old) to calculate the conversion coefficients which transform the exposure at skin to equivalent doses at several organs and tissues of interest. In order to check the computer program, simulations were performed for adult patients using the original code (ADAM.FOR developed at the GSF-Germany) and the adapted program (MCDRO.PAS). Good agreement between results obtained with both codes was observed. Irradiations of the incisive, canine and molar teeth were simulated. The conversion factors were calculated for the following organs and tissues: thyroid, active bone narrow (head and whole body), bone (facial skeleton, cranium and whole body), skin (head and whole body) and crystalline. Based on the obtained results, it follows that the younger the patient and the larger the field area, the higher the dose in assessed organs and tissues. The variation of the source-skin distance does not change the conversion coefficients. On the other hand, the increase in the voltage applied to the X-ray tube causes an increase in the calculated conversion coefficients. (author)

  3. Serum metabonomics of rats irradiated by low-dose γ-rays

    Directory of Open Access Journals (Sweden)

    Ying HE

    2014-08-01

    Full Text Available Objective To explore the effect of low-dose γ-rays on the metabolites in rat serum. Methods Sixteen healthy male SD rats were randomly divided into control group and irradiated group (n=8. The rats in irradiated group were irradiated by 60Co γ-rays with a dose rate of 72mGy/h for 7 days (1 hour per day. At the 7th day after irradiation, blood samples were taken from abdominal aorta to obtain the serum. The metabolic fingerprints of serum were obtained from the two groups of rats, and 1H nuclear magnetic resonance (NMR spectroscopy, principal component analysis (PCA and orthogonal signal correction-partial least squares (OSC-PLS method were used for pattern recognition, and the difference in metabolite profile between two groups was identified by SIMCA-P software. Results The rat serum 1H NMR spectra revealed a significant difference between control group and irradiated group, the OSC-PLS plots of the serum samples presented marked clustering between two groups. Compared with the control group, the content of lipid, glucose, creatine, glycine/glucose, high density lipoprotein, low density lipoprotein, very low density lipoprotein/low density lipoprotein and unsaturated fatty acid increased, while the content of lactic acid, threonine/lipid, alanine, N-acetyl glycoprotein 1, N-acetyl glycoprotein 2, saturated fatty acid and phosphatidyl choline decreased in irradiated group. Conclusion Irradiation with low-dose γ-ray could induce changes in metabolites in rat serum, concerning mainly immune function, energy metabolism, carbohydrate metabolism and lipid metabolism. DOI: 10.11855/j.issn.0577-7402.2014.07.02

  4. In-flight calibration system for the INTEGRAL x-ray monitor

    DEFF Research Database (Denmark)

    Costa, E.; Feroci, M.; Barbanera, L.

    1996-01-01

    of Amptek Cool-X15 X-ray generators. The latter is a novel product, based on a pyroelectric crystal used to generate energetic electrons that produce fluorescence lines by hitting a metallic target. We plan to use the four low intensity radioactive sources for monitoring the four independent anode chains......JEM-X is the x-ray monitor serving the two gamma-ray experiments imager and spectrometer onboard the ESA's INTEGRAL satellite. Due to the intrinsic weakness of the celestial sources in the gamma energy range they will need very long integration times. During these long pointings JEM-X will be able...... to detect very small variations on most x-ray sources, but only if accurately calibrated. The in- flight calibration system of the JEM-X experiment is devoted to measure the response of the detection chain (detector plus electronics) in a small set of positions and energies. The data from this system...

  5. Optical fiber sensor for low dose gamma irradiation monitoring

    Science.gov (United States)

    de Andrés, Ana I.; Esteban, Ã.`scar; Embid, Miguel

    2016-05-01

    An optical fiber gamma ray detector is presented in this work. It is based on a Terbium doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillating powder which cover a chemically etched polymer fiber tip. This etching improves the fluorescence gathering by the optical fiber. The final diameter has been selected to fulfill the trade-off between light gathering and mechanical strength. Powder has been encapsulated inside a microtube where the fiber tip is immersed. The sensor has been irradiated with different air Kerma doses up to 2 Gy/h with a 137Cs source, and the spectral distribution of the fluorescence intensity has been recorded in a commercial grade CCD spectrometer. The obtained signal-to-noise ratio is good enough even for low doses, which has allowed to reduce the integration time in the spectrometer. The presented results show the feasibility for using low cost equipment to detect/measure ionizing radiation as gamma rays are.

  6. Establishment of radiation doses for pediatric X-ray examinations in a large pediatric hospital in Turkey

    International Nuclear Information System (INIS)

    Olgar, T.; Sahmaran, T.

    2017-01-01

    Pediatric patients are more sensitive to ionizing radiation when compared with adults. The aim of this study was to evaluate the radiation doses for some common pediatric x-ray examinations performed with various digital radiography systems. Quality control tests of the digital radiography systems were carried out according to international published protocols before the pediatric dose measurements. Radiation dose measurement was performed by using the x-ray tube outputs and thermoluminescent dosimeter dose measurement methods. In the present study, radiation doses were assessed for 247 chest, 230 pelvis, 194 skull and 73 abdomen x-ray examinations and in total 744 pediatric patients doses were measured. Pediatric patients were classified into four age groups 0-1, 1-5, 5-10 and 10-15 years as given by European Commission guidance. Effective doses were determined for each examination using a PCXMC 2.0 Monte Carlo program. The mean measured entrance skin doses for the age interval 1-5 years and AP projection by using tube output measurement methods were 149 μGy for chest, 304 μGy for pelvis, 387 μGy for skull and 199 μGy for abdomen examinations. The radiation dose results obtained in this study were in the range of the published results in the literature. (authors)

  7. Monitoring of high-radiation areas for the assessment of operational and body doses

    International Nuclear Information System (INIS)

    Chen, T.J.; Tung, C.J.; Yeh, W.W.; Liao, R.Y.

    2004-01-01

    The International Commission on Radiological Protection (ICRP) recommended a system of dose limits for the protection of ionizing radiation. This system was established based on the effective dose, E, and the equivalent dose to an organ or tissue, H T , to assess stochastic and deterministic effects. In radiation protection monitoring for external radiation, operational doses such as the deep dose equivalent index, H I,d , shallow dose equivalent index, H I,s , ambient dose equivalent [1,4-6], H*, directional dose equivalent, H', individual dose equivalent-penetrating, H p , and individual dose equivalent-superficial, H s , are implemented. These quantities are defined in an International Commission on Radiation Units and Measurements (ICRU) sphere and in an anthropomorphic phantom under simplified irradiation conditions. They are useful when equivalent doses are below the corresponding limits. In the case of equivalent doses far below the limits, the exposure or air kerma is commonly applied. For workers exposed to high levels of radiation, accurate assessments of effective doses and equivalent doses may be needed in order to acquire legal and health information. In the general principles of monitoring for radiation protection of workers, ICRP recommended that: 'A graduated response is advocated for the monitoring of the workplace and for individual monitoring - graduated in the sense that a greater degree of monitoring is deemed to be necessary as doses increase of as unpredictability increases. Gradually more complex or realistic procedures should be adopted as doses become higher. Thus, at low dose equivalents (corresponding say to those within Working Condition B) dosimetric quantities might be used directly to assess exposure, since accuracy is not crucial. At intermediate dose equivalents (corresponding say to Working Condition A and slight overexposures) somewhat greater accuracy is warranted, and the conversion coefficients from dosimetric to radiation

  8. Radon continuous monitoring in Altamira Cave (northern Spain) to assess user's annual effective dose

    International Nuclear Information System (INIS)

    Lario, J.; Sanchez-Moral, S.; Canaveras, J.C.; Cuezva, S.; Soler, V.

    2005-01-01

    In this work, we present the values of radon concentration, measured by continuous monitoring during a complete annual cycle in the Polychromes Hall of Altamira Cave in order to undertake more precise calculations of annual effective dose for guides and visitors in tourist caves. The 222 Rn levels monitored inside the cave ranges from 186 Bq m -3 to 7120 Bq m -3 , with an annual average of 3562 Bq m -3 . In order to more accurately estimate effective dose we use three scenarios with different equilibrium factors (F=0.5, 0.7 and 1.0) together with different dose conversion factors proposed in the literature. Neither effective dose exceeds international recommendations. Moreover, with an automatic radon monitoring system the time remaining to reach the maximum annual dose recommended could be automatically updated

  9. Monitoring of blood-10B concentration for boron neutron capture therapy using prompt gamma-ray analysis

    International Nuclear Information System (INIS)

    Raaijmakers, C.P.J.; Konijnenberg, M.W.; Dewit, L.; Mijnheer, B.J.; Haritz, D.; Huiskamp, R.; Philipp, K.; Siefert, A.; Stecher-Rasmussen, F.

    1995-01-01

    The aim of the present study was to monitor the blood- 10 B concentration of laboratory dogs receiving boron neutron capture therapy, in order to obtain optimal agreement between prescribed and actual dose. A prompt gamma-ray analysis system was developed for this purpose at the High Flux Reactor in Petten. The technique was compared with inductively coupled plasma-atomic emission spectrometry and showed good agreement. A substantial variation in 10 B clearance pattern after administration of borocaptate sodium was found between the different dogs. Consequently, the irradiation commencement was adjusted to the individually determined boron elimination curve. Mean blood- 10 B concentratios during irradiation of 25.8±2.2 μg/g (1 SD, n=18) and 49.3±5.3 μg/g (1 SD, n=17) were obtained for intended concentrations of 25 μg/g and 50 μg/g, respectively. These variations are a factor of two smaller than irradiations performed at a uniform post-infusion irradiation starting time. Such a careful bolld- 10 B monitoring procedure is a prerequisite for accurately obtaining such steep dose-response curves as observed during the dog study. (orig.)

  10. Assessment of organ doses by standard X-ray procedures in the GDR

    International Nuclear Information System (INIS)

    Tautz, M.; Brandt, G.A.

    1986-01-01

    A modern method has been described to assess the radiation burden by X-ray procedures with consideration of the standards of our Society for Medical Radiology in the GDR. The underlying methodology is a Monte Carlo computer technique, which simulates stochastically the energy deposition of X-ray photons in a mathematically described heterogeneous anthropomorphic phantom by Rosenstein (US Department of Health, Education and Welfare). To apply the procedure specific values for the following parameters must be determined for each dose estimation: projection and view, X-ray field size and location entrance exposure at skin surface, beam quality, source-to-image receptor distance. The base data are obtained in terms of tissue-air ratio. Organ doses were calculated for chest, urography, skull, cervical spine, thoracic spine, lumbar spine, pelvis and lymphography. Concluding possibilities have been discussed for reduction of radiation burden. 9 refs., 6 figs., 9 tabs. (author)

  11. Monitoring Instrument for X-Ray Box

    CERN Document Server

    Cifuentes Ospina, Alberto; Kuehn, Susanne; Schaepe, Steffen; CERN. Geneva. EP Department

    2017-01-01

    A humidity and temperature readout instrument has been designed and implemented in order to monitor the X-Ray Box used for testing the silicon detectors prototypes of the ITk. The sensors are connected to an Arduino Mega board equipped with 16 analog inputs and a serial port to a computer. A user-friendly software has been also designed in order to give an easy access to all measurements.

  12. Comparative survey of site and personnel monitoring characteristics for operation of various types of diagnostic-X ray equipment

    International Nuclear Information System (INIS)

    Lyarskij, P.P.; Zol'nikova, N.I.

    1977-01-01

    Diagnostic X-ray machines in present use at medical facilities differ in design and operating parameters, this diversity producing, in turn, a variety of local radiological situations and levels of personnel exposure. Based on radiological safety characterization of working conditions, the authors present a breakdown of contemporary diagnostic X-ray equipment types, based on detailed examination of each group in terms of their associated site monitoring and dosimetry patterns. The paper reports data on personnel exposure levels not only as a function of equipment design and operating characteristics but also according to types of occupational activities for particular medical personnel groups (radiologists, surgeons, anesthesiologists, etc.). Included are health physics data for domestic and foreign X-ray equipment, levels of local and absorbed doses for radiologists, cardiovascular surgeons, neurosurgeons, urologists, traumatologists, anesthesiologists, etc. Measures are recommended for optimizing their activities from the standpoint of radiation safety. (author)

  13. Radiation monitoring in interventional cardiology: a requirement

    Science.gov (United States)

    Rivera, T.; Uruchurtu, E. S.

    2017-01-01

    The increasing of procedures using fluoroscopy in interventional cardiology procedures may increase medical and patients to levels of radiation that manifest in unintended outcomes. Such outcomes may include skin injury and cancer. The cardiologists and other staff members in interventional cardiology are usually working close to the area under examination and they receive the dose primarily from scattered radiation from the patient. Mexico does not have a formal policy for monitoring and recording the radiation dose delivered in hemodynamic establishments. Deterministic risk management can be improved by monitoring the radiation delivered from X-ray devices. The objective of this paper is to provide cardiologist, techniques, nurses, and all medical staff an information on DR levels, about X-ray risks and a simple a reliable method to control cumulative dose.

  14. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    International Nuclear Information System (INIS)

    Fehlau, P.E.

    1994-01-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. The authors compared the influence of the two methods of integration on detecting neutrons and gamma rays, and they examined the effectiveness of other design factors and the methods for signal detection as well

  15. A deep convolutional neural network using directional wavelets for low-dose X-ray CT reconstruction.

    Science.gov (United States)

    Kang, Eunhee; Min, Junhong; Ye, Jong Chul

    2017-10-01

    Due to the potential risk of inducing cancer, radiation exposure by X-ray CT devices should be reduced for routine patient scanning. However, in low-dose X-ray CT, severe artifacts typically occur due to photon starvation, beam hardening, and other causes, all of which decrease the reliability of the diagnosis. Thus, a high-quality reconstruction method from low-dose X-ray CT data has become a major research topic in the CT community. Conventional model-based de-noising approaches are, however, computationally very expensive, and image-domain de-noising approaches cannot readily remove CT-specific noise patterns. To tackle these problems, we want to develop a new low-dose X-ray CT algorithm based on a deep-learning approach. We propose an algorithm which uses a deep convolutional neural network (CNN) which is applied to the wavelet transform coefficients of low-dose CT images. More specifically, using a directional wavelet transform to extract the directional component of artifacts and exploit the intra- and inter- band correlations, our deep network can effectively suppress CT-specific noise. In addition, our CNN is designed with a residual learning architecture for faster network training and better performance. Experimental results confirm that the proposed algorithm effectively removes complex noise patterns from CT images derived from a reduced X-ray dose. In addition, we show that the wavelet-domain CNN is efficient when used to remove noise from low-dose CT compared to existing approaches. Our results were rigorously evaluated by several radiologists at the Mayo Clinic and won second place at the 2016 "Low-Dose CT Grand Challenge." To the best of our knowledge, this work is the first deep-learning architecture for low-dose CT reconstruction which has been rigorously evaluated and proven to be effective. In addition, the proposed algorithm, in contrast to existing model-based iterative reconstruction (MBIR) methods, has considerable potential to benefit from

  16. Investigation of organ dose difference of age phantoms for medical X-ray examinations

    International Nuclear Information System (INIS)

    Park, Sang Hyun; Kim, Woo Ran; Lee, Jai Ki; Lee, Choon Sik

    2003-01-01

    Methodology for calculating the organ equivalent doses and the effective doses of pediatric and adult patients undergoing medical X-ray examinations were established. The MIRD-type mathematical phantoms of 4 age groups were constructed with addition of the esophagus to the same phantoms. Two typical examination procedures, chest PA and abdomen AP, were simulated for the pediatric patients as well as the adult as illustrative examples. The results confirmed that patients pick up approximate 0.03 mSv of effective dose from a single chest PA examination, and 0.4 to 1.7 mSv from an abdomen AP examination depending on the ages. For dose calculations where irradiation is made with a limited field, the details of the position, size and shape of the organs and the organ depth from the entrance surface considerably affect the resulting doses. Therefore, it is important to optimize radiation protection by control of X-ray properties and beam examination field. The calculation result, provided in this study, can be used to implement optimization for medical radiation protection

  17. Establishment and verification of dose-response curve of chromosomal aberrations after exposure to very high dose γ-ray

    International Nuclear Information System (INIS)

    Chen Ying; Luo Yisheng; Cao Zhenshan; Liu Xiulin

    2006-01-01

    To estimate accurately biological dose of the victims exposed to high dose, the dose-response curves of chromosome aberration induced by 6-22 Gy 60 Co γ-ray were established. Human peripheral blood in vitro was irradiated, then lymphocytes were concentrated, cultured 52h, 68h and 72h and harvested. The frequencies of dicentrics (multi-centrics) and rings were counted and compared between different culture times. The dose-response curves and equations were established, as well as verified with high dose exposure accidents. The experiment showed that the culture time should be prolonged properly after high dose exposure, and no significant differences were observed between 52-72h culture. The dose-response curve of 6-22 Gy fitted to linear-square model Y=-2.269 + 0.776D - 7.868 x 10 -3 D 2 and is reliable through verification of the accident dose estimations. In this study, the dose-response curve and equation of chromosome dic + r after 6-22 Gy high dose irradiation were established firstly, and exact dose estimation can be achieved according to it. (authors)

  18. Response of radiation monitors for ambient dose equivalent, H*(10)

    International Nuclear Information System (INIS)

    Grecco, Claudio Henrique dos Santos

    2001-01-01

    Radiation monitors are used all over the world to evaluate if places with presence of ionising radiation present safe conditions for people. Radiation monitors should be tested according to international or national standards in order to be qualified for use. This work describes a methodology and procedures to evaluate the energy and angular responses of any radiation monitor for ambient dose equivalent, H*(10), according to the recommendations of ISO and IEC standards. The methodology and the procedures were applied to the Monitor Inteligente de Radiacao MIR 7026, developed by the Instituto em Engenharia Nuclear (IEN), to evaluate and to adjust its response for H*(10), characterizing it as an ambient dose equivalent meter. The tests were performed at the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI), at Instituto de Radioprotecao e Dosimetria (IRD), and results showed that the Monitor Inteligente de Radiacao MIR 7026 can be used as an EI*(10) meter, in accordance to the IEC 60846 standard requirements. The overall estimated uncertainty for the determination of the MIR 7026 response, in all radiation qualities used in this work, was 4,5 % to a 95 % confidence limit. (author)

  19. Effects of low-dose continuously fractionated X-ray irradiation on murine peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Xie Yi; Zhang Hong; Dang Bingrong; Hao Jifang; Guo Hongyun; Wang Xiaohu

    2007-01-01

    For estimating biological risks from low doses continual irradiation, we investigated the effects of exposure to continuously fractionated X-rays on murine immune system. The BALB/c mice were irradiated with 0.07Gy at the first day and 0.08 Gy/d in the following 12 days at a dose rate of 0.2 Gy/min. The peripheral blood lymphocyte cycle and death were determined by flow cytometry at the cumulative doses of 0, 0.07, 0.23, 0.39, 0.55, 0.71, 0.87 and 1.03 Gy respectively. The results showed that the cycle of peripheral blood lymphocyte was arrested in G 0 /G 1 at cumulative doses of 0.07, 0.23, 0.71 and 0.87 Gy, and in G 2 /M at cumulative doses of 0.39 and 1.03 Gy; the percentage of death of peripheral blood lymphocyte was ascended with dose increasing, and reached the death peak at cumulative doses of 0.71 Gy. The results suggested that low doses continual X-rays total-body irradiated could result in changes of cellular cycle and death, and some damages to immunocytes, which accorded to linear square model. (authors)

  20. Evaluation of build-up dose from 6 MV X-rays under pelvic and abdominal patient immobilisation devices

    Energy Technology Data Exchange (ETDEWEB)

    Cheung Tsang; Butson, M.J.Martin J. E-mail: mbutson@usa.netmbutson@guessmail.com; Yu, P.K.N

    2002-06-01

    The use of pelvic and abdominal immobilisation devices in radiotherapy is required for accurate positioning and repositioning of patients during their fractionated treatment delivered normally over a period of 5-6 weeks. 6 MV X-rays produced by a medical linear accelerator have a skin sparing effect whereby the skin dose delivered is considerably less than that received by the tumour. The treatment through a vacuum compressed immobilisation device (Vacbag) however increases the dose delivered to the skin by interactions of the X-rays within the Vacbag material. For example, the basal layer doses increased from 16% for an open field to 52% of maximum with a bag thickness of 2.5 cm for a 10 cmx10 cm field at 6 MV X-ray energy. At the same field size the dermal skin layer (1 mm depth) doses increased from 44% (no bag) to 60% for a bag thickness of 2.5 cm at 6 MV X-rays. The Vacbag should be placed outside the treatment field whenever possible to keep skin dose to a minimum level.

  1. Evaluation of build-up dose from 6 MV X-rays under pelvic and abdominal patient immobilisation devices

    International Nuclear Information System (INIS)

    Cheung Tsang; Butson, M.J.Martin J.; Yu, P.K.N.

    2002-01-01

    The use of pelvic and abdominal immobilisation devices in radiotherapy is required for accurate positioning and repositioning of patients during their fractionated treatment delivered normally over a period of 5-6 weeks. 6 MV X-rays produced by a medical linear accelerator have a skin sparing effect whereby the skin dose delivered is considerably less than that received by the tumour. The treatment through a vacuum compressed immobilisation device (Vacbag) however increases the dose delivered to the skin by interactions of the X-rays within the Vacbag material. For example, the basal layer doses increased from 16% for an open field to 52% of maximum with a bag thickness of 2.5 cm for a 10 cmx10 cm field at 6 MV X-ray energy. At the same field size the dermal skin layer (1 mm depth) doses increased from 44% (no bag) to 60% for a bag thickness of 2.5 cm at 6 MV X-rays. The Vacbag should be placed outside the treatment field whenever possible to keep skin dose to a minimum level

  2. Exploratory X-ray monitoring of luminous radio-quiet quasars at high redshift: Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Shemmer, Ohad; Stein, Matthew S. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Brandt, W. N.; Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Paolillo, Maurizio [Dipartimento di Scienze Fisiche, Università Federico II di Napoli, via Cinthia 6, I-80126 Napoli (Italy); Kaspi, Shai [School of Physics and Astronomy and the Wise Observatory, Tel Aviv University, Tel Aviv 69978 (Israel); Vignali, Cristian [Dipartimento di Astronomia, Università degli studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Gibson, Robert R., E-mail: ohad@unt.edu [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2014-03-10

    We present initial results from an exploratory X-ray monitoring project of two groups of comparably luminous radio-quiet quasars (RQQs). The first consists of four sources at 4.10 ≤ z ≤ 4.35, monitored by Chandra, and the second is a comparison sample of three sources at 1.33 ≤ z ≤ 2.74, monitored by Swift. Together with archival X-ray data, the total rest-frame temporal baseline spans ∼2-4 yr and ∼5-13 yr for the first and second group, respectively. Six of these sources show significant X-ray variability over rest-frame timescales of ∼10{sup 2}-10{sup 3} days; three of these also show significant X-ray variability on rest-frame timescales of ∼1-10 days. The X-ray variability properties of our variable sources are similar to those exhibited by nearby and far less luminous active galactic nuclei (AGNs). While we do not directly detect a trend of increasing X-ray variability with redshift, we do confirm previous reports of luminous AGNs exhibiting X-ray variability above that expected from their luminosities, based on simplistic extrapolation from lower luminosity sources. This result may be attributed to luminous sources at the highest redshifts having relatively high accretion rates. Complementary UV-optical monitoring of our sources shows that variations in their optical-X-ray spectral energy distribution are dominated by the X-ray variations. We confirm previous reports of X-ray spectral variations in one of our sources, HS 1700+6416, but do not detect such variations in any of our other sources in spite of X-ray flux variations of up to a factor of ∼4. This project is designed to provide a basic assessment of the X-ray variability properties of RQQs at the highest accessible redshifts that will serve as a benchmark for more systematic monitoring of such sources with future X-ray missions.

  3. Personal Doses Recorded by Service of Personal Dosimetry

    International Nuclear Information System (INIS)

    Mihai, F.; Gheorghiu, A.; Stochioiu, A.; Udup, E.

    2009-01-01

    In this work we present occupational exposure statistics on: number of workers on different dose ranges; average of the mean annual doses (MAD) over the period 2000 - 2007 on all monitored workers as well as on those who have been received doses over the minimum detection limit (MDL). The statistic is made on different types of nuclear laboratories. The data are obtained on almost 1000 workers occupational exposure to different sources of radiations (gamma and X-ray) and monitored by Photo dosimetry Survey Unit, IFIN - HH. These results point out the evolution of the individual doses received during eight years and can be used to analyse the need of radiation protection in different nuclear facilities from Romania

  4. Genetic effects of low x-ray doses. Progress report, October 1, 1975--September 30, 1976

    International Nuclear Information System (INIS)

    Abrahamson, S.; Meyer, H.U.

    1976-09-01

    Experiments on dose-kinetics of x-ray induced sexlinked lethal mutations in Drosophila oogonia were continued. A wide range of doses was tested, with special emphasis on the low-dose range (20 to 500R). This year more data were added for O R, 200, 500, 1500R and some high doses. Oogonia of adult females were irradiated, and only one daughter from each experimental parent-female was analyzed for a new lethal in her maternal X-chromosome. Thus no clusters of mutations of identical origin are encountered. The extensive accumulated data do not support the linearity principle, firmly established for recessive mutations induced in mature spermatozoa for high doses down to very low x-ray doses. A mathematical model describing the mutational yield is included that suggests that recessive mutations, like chromosome aberrations, result from both one-track and two-track events, with the latter playing an increasingly important role at higher doses

  5. Dose evaluation in paediatric patients undergoing chest X-ray examinations

    Science.gov (United States)

    Piantini, F.; Schelin, H. R.; Denyak, V.; Bunick, A. P.; Legnani, A.; Ledesma, J. A.; Filipov, D.; Paschuk, S. A.

    2017-11-01

    This study aimed to estimate the incident air kerma in chest X-ray examinations, for lateral (LAT) and anterior-posterior (AP) (together with posterior-anterior (PA)) projections, in one of the largest paediatric hospitals in Brazil, and to compare these with the results obtained in a general hospital of the same city. The dosimetric results were analysed along with the patient characteristics and radiographer strategies. The examinations of 225 (119 male and 106 female) patients were studied and 389 X-ray scans (200 AP/PA projections and 189 LAT projections) of paediatric patients were acquired. For analysis of the results, the patients were divided into the following age groups: 0-1 y, 1-5 y, 5-10 y, and 10-15 y. Patient's thickness can be determined from age, height or weight with an uncertainty of 20-30%. In different hospitals, the difference in patient's thicknesses between the same age groups can reach 25-55%. A minimal correlation between the patient dose and thickness was observed, with a 4-fold difference in the dose for patients of the same thickness. By standardizing radiological protocols, it should be possible to keep the dose within intervals of 50-100 μGy for LAT projection and 40-80 μGy for AP/PA projection.

  6. Response of human and rabbit lymphocytes to low doses of X-rays

    International Nuclear Information System (INIS)

    Fabry, L.

    1982-01-01

    The response of human and rabbit lymphocytes to low doses of X-rays was studied by the yields of dicentrics in first division metaphases. For both species, the dose-response curve was best fitted to the linear-quadratic model with a linear component predominating up to 67 and 42 rad respectively for man and rabbit. A calibration curve (5-400 rad) was obtained by combining the present results on man with previous data at higher doses. On the other hand, it appears that, at low doses, the radiosentivity of human lymphocytes is significantly higher than that of rabbit lymphocytes [fr

  7. Accuracy of neutron dose evaluation in the area monitoring for LHD experiments

    CERN Document Server

    Yamanishi, H; Uda, T; Tanahashi, S; Saitou, M; Handa, H

    2000-01-01

    The error in the evaluation of neutron dose during calculation of the neutron field around the large helical device (LHD) in D-D operation is discussed. The expected neutron dose at each monitoring point was derived from the dose conversion factor and neutron fluence data, which was calculated with the radiation transport code DOT-3.5. In contrast, the detected dose at the neutron counter was obtained from the fluence data and the detector response given by calculation with MCNP-4b. The neutron counter used in these calculations consisted of a helium-3 proportional counter with a cylindrical polyethylene moderator. According to the results of the calculations, the ratio of the detected dose to the expected dose was found to lie in the range 1.0-3.0 on the outdoor monitoring points. Since the response of a single neutron counter may lead to inconsistencies in the dose conversion factor, we attempted to minimize these inconsistencies by using a pair of counters with moderators of different thickness. The ratio ...

  8. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2016-10-15

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  9. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    International Nuclear Information System (INIS)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian

    2016-01-01

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  10. Radiation doses to paediatric patients and comforters undergoing chest x rays

    International Nuclear Information System (INIS)

    Sulieman, A.; Vlychou, M.; Tsougos, I.; Theodorou, K.

    2011-01-01

    Pneumonia is an important cause of hospital admission among children in the developed world and it is estimated to be responsible for 3-18 % of all paediatric admissions. Chest X ray is an important examination for pneumonia diagnosis and for evaluation of complications. This study aims to determine the entrance surface dose (ESD), organ, effective doses and propose a local diagnostic reference level. The study was carried out at the university hospital of Larissa (Greece). Patients were divided into three groups: organ and effective doses were estimated using National Radiological Protection Board software. The ESD was determined by thermoluminescent dosemeters for 132 children and 76 comforters. The average ESD value was 55±8 μGy. The effective dose for patients was 11.2±5 μSv. The mean radiation dose for comforter is 22±3 mGy. The radiation dose to the patients is well within dose constraint, in the light of the current practice. (authors)

  11. 10 CFR 20.1502 - Conditions requiring individual monitoring of external and internal occupational dose.

    Science.gov (United States)

    2010-01-01

    ... external and internal occupational dose. Each licensee shall monitor exposures to radiation and radioactive... 10 Energy 1 2010-01-01 2010-01-01 false Conditions requiring individual monitoring of external and internal occupational dose. 20.1502 Section 20.1502 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR...

  12. Entrance skin dose on patients undergoing X-ray examinations at ...

    African Journals Online (AJOL)

    survey was conducted on the Entrance Skin Dose (ESD) in patients undergoing X-ray examinations [Skull Postero-Anterior (PA), Skull Lateral (LAT), Chest Postero-Anterior (PA), Chest Lateral (LAT), Abdomen Antero-Posterior (AP) and Pelvis Antero-Posterior (AP)] in five hospitals/Xray centres in Yaba, Lagos State, Nigeria ...

  13. X-ray beam-position feedback system with easy-to-use beam-position monitor.

    Science.gov (United States)

    Park, Jae Yeon; Kim, Yesul; Lee, Sangsul; Lim, Jun

    2018-05-01

    X-ray beam-position stability is indispensable in cutting-edge experiments using synchrotron radiation. Here, for the first time, a beam-position feedback system is presented that utilizes an easy-to-use X-ray beam-position monitor incorporating a diamond-fluorescence screen. The acceptable range of the monitor is above 500 µm and the feedback system maintains the beam position within 3 µm. In addition to being inexpensive, the system has two key advantages: it works without a scale factor for position calibration, and it has no dependence on X-ray energy, X-ray intensity, beam size or beam shape.

  14. Simple method to estimate mean heart dose from Hodgkin lymphoma radiation therapy according to simulation X-rays.

    Science.gov (United States)

    van Nimwegen, Frederika A; Cutter, David J; Schaapveld, Michael; Rutten, Annemarieke; Kooijman, Karen; Krol, Augustinus D G; Janus, Cécile P M; Darby, Sarah C; van Leeuwen, Flora E; Aleman, Berthe M P

    2015-05-01

    To describe a new method to estimate the mean heart dose for Hodgkin lymphoma patients treated several decades ago, using delineation of the heart on radiation therapy simulation X-rays. Mean heart dose is an important predictor for late cardiovascular complications after Hodgkin lymphoma (HL) treatment. For patients treated before the era of computed tomography (CT)-based radiotherapy planning, retrospective estimation of radiation dose to the heart can be labor intensive. Patients for whom cardiac radiation doses had previously been estimated by reconstruction of individual treatments on representative CT data sets were selected at random from a case-control study of 5-year Hodgkin lymphoma survivors (n=289). For 42 patients, cardiac contours were outlined on each patient's simulation X-ray by 4 different raters, and the mean heart dose was estimated as the percentage of the cardiac contour within the radiation field multiplied by the prescribed mediastinal dose and divided by a correction factor obtained by comparison with individual CT-based dosimetry. According to the simulation X-ray method, the medians of the mean heart doses obtained from the cardiac contours outlined by the 4 raters were 30 Gy, 30 Gy, 31 Gy, and 31 Gy, respectively, following prescribed mediastinal doses of 25-42 Gy. The absolute-agreement intraclass correlation coefficient was 0.93 (95% confidence interval 0.85-0.97), indicating excellent agreement. Mean heart dose was 30.4 Gy with the simulation X-ray method, versus 30.2 Gy with the representative CT-based dosimetry, and the between-method absolute-agreement intraclass correlation coefficient was 0.87 (95% confidence interval 0.80-0.95), indicating good agreement between the two methods. Estimating mean heart dose from radiation therapy simulation X-rays is reproducible and fast, takes individual anatomy into account, and yields results comparable to the labor-intensive representative CT-based method. This simpler method may produce a

  15. Simple Method to Estimate Mean Heart Dose From Hodgkin Lymphoma Radiation Therapy According to Simulation X-Rays

    Energy Technology Data Exchange (ETDEWEB)

    Nimwegen, Frederika A. van [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Cutter, David J. [Clinical Trial Service Unit, University of Oxford, Oxford (United Kingdom); Oxford Cancer Centre, Oxford University Hospitals NHS Trust, Oxford (United Kingdom); Schaapveld, Michael [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Rutten, Annemarieke [Department of Radiology, The Netherlands Cancer Institute, Amsterdam (Netherlands); Kooijman, Karen [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Krol, Augustinus D.G. [Department of Radiation Oncology, Leiden University Medical Center, Leiden (Netherlands); Janus, Cécile P.M. [Department of Radiation Oncology, Erasmus MC Cancer Center, Rotterdam (Netherlands); Darby, Sarah C. [Clinical Trial Service Unit, University of Oxford, Oxford (United Kingdom); Leeuwen, Flora E. van [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Aleman, Berthe M.P., E-mail: b.aleman@nki.nl [Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam (Netherlands)

    2015-05-01

    Purpose: To describe a new method to estimate the mean heart dose for Hodgkin lymphoma patients treated several decades ago, using delineation of the heart on radiation therapy simulation X-rays. Mean heart dose is an important predictor for late cardiovascular complications after Hodgkin lymphoma (HL) treatment. For patients treated before the era of computed tomography (CT)-based radiotherapy planning, retrospective estimation of radiation dose to the heart can be labor intensive. Methods and Materials: Patients for whom cardiac radiation doses had previously been estimated by reconstruction of individual treatments on representative CT data sets were selected at random from a case–control study of 5-year Hodgkin lymphoma survivors (n=289). For 42 patients, cardiac contours were outlined on each patient's simulation X-ray by 4 different raters, and the mean heart dose was estimated as the percentage of the cardiac contour within the radiation field multiplied by the prescribed mediastinal dose and divided by a correction factor obtained by comparison with individual CT-based dosimetry. Results: According to the simulation X-ray method, the medians of the mean heart doses obtained from the cardiac contours outlined by the 4 raters were 30 Gy, 30 Gy, 31 Gy, and 31 Gy, respectively, following prescribed mediastinal doses of 25-42 Gy. The absolute-agreement intraclass correlation coefficient was 0.93 (95% confidence interval 0.85-0.97), indicating excellent agreement. Mean heart dose was 30.4 Gy with the simulation X-ray method, versus 30.2 Gy with the representative CT-based dosimetry, and the between-method absolute-agreement intraclass correlation coefficient was 0.87 (95% confidence interval 0.80-0.95), indicating good agreement between the two methods. Conclusion: Estimating mean heart dose from radiation therapy simulation X-rays is reproducible and fast, takes individual anatomy into account, and yields results comparable to the labor

  16. Sequential measurements of spectrum and dose for cosmic-ray neutrons on the ground

    International Nuclear Information System (INIS)

    Hirabayashi, N.; Nunomiya, T.; Suzuki, H.; Nakamura, T.

    2002-01-01

    The earth is continually bathed in high-energy particles that come from outside the solar system, known as galactic cosmic rays. When these particles penetrate the magnetic fields of the solar system and the Earth and reach the Earth's atmosphere, they collide with atomic nuclei in air and secondary cosmic rays of every kind. On the other hand, levels of accumulation of the semiconductor increase recently, and the soft error that the cosmic-ray neutrons cause has been regarded as questionable. There have been long-term measurements of cosmic-ray neutron fluence at several places in the world, but no systematic study on cosmic-ray neutron spectrum measurements. This study aimed to measure the cosmic-ray neutron spectrum and dose on the ground during the solar maximum period of 2000 to 2002. Measurements have been continuing in a cabin of Tohoku University Kawauchi campus, by using five multi-moderator spectrometers (Bonner sphere), 12.7 cm diam by 12.7 cm long NE213 scintillator, and rem counter. The Bonner sphere uses a 5.08 cm diam spherical 3 He gas proportional counter and the rem counter uses a 12.7 cm diam 3 He gas counter. The neutron spectra were obtained by unfolding from the count rates measured with the Bonner sphere using the SAND code and the pulse height spectra measured with the NE213 scintillator using the FORIST code . The cosmic- ray neutron spectrum and ambient dose rates have been measured sequentially from April 2001. Furthermore, the correlation between ambient dose rate and the atmospheric pressure was investigated with a barometer. We are also very much interested in the variation of neutron spectrum following big solar flares. From the sequential measurements, we found that the cosmic-ray neutron spectrum has two peaks at around 1 MeV and at around 100 MeV, and the higher energy peak increases with a big solar flare

  17. Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells

    International Nuclear Information System (INIS)

    Anderson, D.

    1981-01-01

    The fractionated dose technique has been used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 5 1/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment

  18. Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells

    International Nuclear Information System (INIS)

    Anderson, D.

    1981-01-01

    The fractionated dose technique was used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 51/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment. (author)

  19. Measurements of the Cosmic Rays Dose at Different Altitudes of Iran

    International Nuclear Information System (INIS)

    Faghihi, R.; Mehdizadeh, S.; Jafarizadeh, M.; Sina, S.; Zehtabian, M.; Taheri, M.

    2012-01-01

    The amount of cosmic rays varies widely with the altitude, latitude and longitude in each region. In this study, the radiation doses due to the cosmic rays were estimated in two steps: in the first step, the neutron and gamma components of the radiation dose were measured for a roundtrip flight on 3 flight routes (Shiraz-Asaluye, Asaluye-Rasht and Shiraz-Mashhad) using a gamma-tracer photon detector and a Thyac 190 N, neutron detector. The minimum values of the measured gamma and neutron doses of 0.15 and 0.04μSv were measured on the Asaluyeh-Shiraz route at the lowest altitude of 19000 ft, while for Rasht-Asaluyeh route at an altitude of 35000 ft those values were found to be 2.52 and 1.09 mSv, respectively. In the second step, a number of air crew members were equipped with thermoluminescence dosimeters (TLD cards) for evaluating the gamma dose and polycarbonate dosimeters (SSNTD) for assessing the neutron dose for one year. The measured value of the annual effective dose received by the crew ranged between 0.5 mSv/y and 1.16 mSv/y, with an average of 0.9 mSv/y for the gamma component and between 0.37 mSv/y and 0.77 mSv/y with an average of 0.61 mSv/y for the neutron component. The results of this investigation are comparable with the investigations that have been conducted in other countries. For instance in UK, the reported annual effective dose of air crew is about 2 mSv, and in Canada, it is estimated to be between 1 to 5 mSv, depending on the flight situations (such as the latitude and longitude of the cities, the flight altitude, etc).

  20. Dose distribution at junctional area abutting X-ray and electron fields

    International Nuclear Information System (INIS)

    Yang, Kwang Mo

    2004-01-01

    For the head and neck radiotherapy, abutting photon field with electron field is frequently used for the irradiation of posterior neck when tolerable dose on spinal cord has been reached. Using 6 MV X-ray and 9 MeV electron beams of Clinac1800(Varian, USA) linear accelerator, we performed film dosimetry by the X-OMAT V film of Kodak in solid water phantom according to depths(0 cm, 1.5 cm, 3 cm, 5 cm). 6 MV X-ray and 9 MeV electron(1 Gy) were exposes to 8 cm depth and surface(SSD 100 cm) of phantom. The dose distribution to the junction line between photon(10 x 10 cm field with block) and electron(15 cm x 15 cm field with block) fields was also measured according to depths(0 cm, 0.5 1.5 cm, 3 cm, 5 cm). At the junction line between photon and electron fields, the hot spot was developed on the side of the photon field and a cold spot was developed on that of the electron field. The hot spot in the photon side was developed at depth 1.5 cm with 7 mm width. The maximum dose of hot spot was increased to 6% of reference doses in the photon field. The cold spot in the electron side was developed at all measured depths(0.5 cm-3 cm) with 1-12.5 mm widths. The decreased dose in the cold spot was 4.5-30% of reference dose in the electron field. When we make use of abutting photon field with electron field for the treatment of head and neck cancer we should consider the hot and cold dose area in the junction of photon and electron field according to location of tumor.

  1. Dose response of micronuclei induced by combination radiation of α-particles and γ-rays in human lymphoblast cells

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ruiping; He, Mingyuan; Dong, Chen; Xie, Yuexia; Ye, Shuang; Yuan, Dexiao [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China)

    2013-01-15

    Highlights: ► α-Particle induced MN had a biphasic dose–response followed by a bystander model. ► MN dose–response of α- and γ-combination IR was similar to that of α-particle. ► α-Particles followed by γ-rays yielded a synergistic effect on MN induction. ► Low dose γ-rays triggered antagonistic and adaptive responses against α-particle. - Abstract: Combination radiation is a real situation of both nuclear accident exposure and space radiation environment, but its biological dosimetry is still not established. This study investigated the dose–response of micronuclei (MN) induction in lymphocyte by irradiating HMy2.CIR lymphoblast cells with α-particles, γ-rays, and their combinations. Results showed that the dose–response of MN induced by γ-rays was well-fitted with the linear-quadratic model. But for α-particle irradiation, the MN induction had a biphasic phenomenon containing a low dose hypersensitivity characteristic and its dose response could be well-stimulated with a state vector model where radiation-induced bystander effect (RIBE) was involved. For the combination exposure, the dose response of MN was similar to that of α-irradiation. However, the yield of MN was closely related to the sequence of irradiations. When the cells were irradiated with α-particles at first and then γ-rays, a synergistic effect of MN induction was observed. But when the cells were irradiated with γ-rays followed by α-particles, an antagonistic effect of MN was observed in the low dose range although this combination radiation also yielded a synergistic effect at high doses. When the interval between two irradiations was extended to 4 h, a cross-adaptive response against the other irradiation was induced by a low dose of γ-rays but not α-particles.

  2. Elementary introduction for personal dose monitoring

    International Nuclear Information System (INIS)

    Bai Guang

    2004-01-01

    According to national laws and regulations, personnel who work with radiation must wear personal dosimeters and receive personal dose monitoring (PDM) provided by professional establishments, which are qualified for this purpose and certificated by the authorities. In this paper, the author gives a brief discussion concerning the Regulations & Purpose of PDM and the historical lessons in accident exposure without PDM. At last, it is pointed out that the PDM provided by the third-party commercial organizations is becoming the trend in this field. (author)

  3. Dose monitoring in radiology departments. Status quo and future perspectives; Dosismonitoring in der Radiologie. Status quo und Zukunftsperspektiven

    Energy Technology Data Exchange (ETDEWEB)

    Boos, J. [Harvard Medical School, Boston, MA (United States). Dept. of Radiology; Duesseldorf Univ. (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Meineke, A. [Cerner Healthcare Services, Idstein (Germany); Bethge, O.T.; Antoch, G.; Kroepil, P. [Duesseldorf Univ. (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie

    2016-05-15

    The number of computed tomography examinations has continuously increased over the last decades and accounts for a major part of the collective radiation dose from medical investigations. For purposes of quality assurance in modern radiology a systematic monitoring and analysis of dose related data from radiological examinations is mandatory. Various ways of collecting dose data are available today, for example the Digital Imaging and Communication in Medicine - Structured Report (DICOM-SR), optical character recognition and DICOM-modality performed procedure steps (MPPS). The DICOM-SR is part of the DICOM-standard and provides the DICOM-Radiation Dose Structured Report, which is an easily applicable and comprehensive solution to collect radiation dose parameters. This standard simplifies the process of data collection and enables comprehensive dose monitoring. Various commercial dose monitoring software devices with varying characteristics are available today. In this article, we discuss legal obligations, various ways to monitor dose data, current dose monitoring software solutions and future perspectives in regard to the EU Council Directive 2013/59/EURATOM.

  4. Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy

    International Nuclear Information System (INIS)

    Higashigaito, K.; Becker, A.S.; Sprengel, K.; Simmen, H.-P.; Wanner, G.; Alkadhi, H.

    2016-01-01

    Aim: To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR). Materials and methods: In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current–time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current–time product. Radiation dose parameters from the software were compared with the individual patient protocols. Image noise was measured and image quality was semi-quantitatively determined. Results: Automatic extraction of radiation dose metrics was feasible and accurate in all (100%) patients. All CT examinations were of diagnostic quality. There were no differences between cohorts 1 and 2 regarding volume CT dose index (CTDI_v_o_l; p=0.62), dose–length product (DLP), and effective dose (ED, both p=0.95), while noise was significantly lower (chest and abdomen, both −38%, p<0.017). Compared to cohort 1, CTDI_v_o_l, DLP, and ED in cohort 3 were significantly lower (all −25%, p<0.017), similar to the noise in the chest (–32%) and abdomen (–27%, both p<0.017). Compared to cohort 2, CTDI_v_o_l (–28%), DLP, and ED (both –26%) in cohort 3 was significantly lower (all, p<0.017), while noise in the chest (+9%) and abdomen (+18%) was significantly higher (all, p<0.017). Conclusion: Automatic radiation dose monitoring software is feasible and accurate, and can be implemented in a clinical setting for evaluating the effects of lowering radiation doses of CT protocols over time. - Highlights: • Automatic dose monitoring software can be

  5. Dose corrections for field obliquity for 45-MV x-ray therapy

    International Nuclear Information System (INIS)

    McGinley, P.H.; Clanton, A.; Downes, B.; Nuskind, J.

    1983-01-01

    The degree of dose perturbation produced by a 25.7-cm-diam circular water phantom was determined for a 45-MV x-ray beam by direct measurement. Data obtained in a circular and a cubical water phantom was utilized to test three accepted techniques (isodose shift, TAR method, and effective SSD method) for the correction of isodose levels to account for patient curvature. In general, the effective SSD method yielded the most accurate results for all depth including the buildup region. An isodose shift factor of 0.8 was found for the 45-MV x-ray beam. Key words: curvature corrections, 45-MV x ray, isodose shift, TAR, effective SSD method

  6. A simple calculation for the determination of organ or tissue dose from medical x-ray diagnosis for stomach and chest

    International Nuclear Information System (INIS)

    Nishizawa, Kanae

    1984-01-01

    A simple calculation method has been developed to determine the organ or tissue doses of patients for typical X-ray diagnoses. The absorbed doses related to radiation-induced stochastic effects were calculated based on the dosimetric parameters experimentally determined and technical parameters for X-ray diagnostic examinations. The present method is principally based on the TRA method for the beam therapy. The dosimetric parameters such as percentage depth-dose curves and isodose curves were measured with ionization chambers in the MixDP phantom. The distance from the incident surface of X-ray beams to the organ or tissue of interest was determined with a mathematical phantom, which was the modified version of the MIRD phantom for the average Japanese adult. The absorbed doses were determined with a simple table look-up method using a computer. The calculated doses were tabulated for various technical parameters of stomach and chest X-ray examinations. The present calculation was applied to the Rando woman phantom to compare with the phantom measurements. The calculated values agree with the experimental doses within 20% discrepancy. It was concluded that the present calculation method can determine organ or tissue doses very simply for various X-ray examinations and that it was valuable for the estimation of population doses and risks from X-ray diagnoses. (author)

  7. Application of radiophotoluminescence dosemeters for environmental monitoring

    International Nuclear Information System (INIS)

    Mihara, A.; Tamura, T.; Mochizuki, T.; Numakunai, T.; Yoshida, Y.; Ohi, Y.

    1993-01-01

    Feasibility study has been made on the radiofluorescence glass (RPL) dosemeters for environmental radiation monitoring. Main items in the laboratory tests are batch uniformities of pre-dose and sensitivity, build-up characteristics of RPL intensity, energy and angular responses, stabilities for RPL reading, anneal cycling and climatic conditional changes. We have determined self-irradiation dose and cosmic ray contribution. Radiation monitoring field test for the RPL dosemeters has been conducted in comparison with the present TLD systems. A procedure manual for the environmental monitoring by the use of RPL dosemeters is in preparation

  8. TH-E-209-01: Fluoroscopic Dose Monitoring and Patient Follow-Up Program at Massachusetts General Hospital

    International Nuclear Information System (INIS)

    Liu, B.

    2016-01-01

    Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.

  9. TH-E-209-01: Fluoroscopic Dose Monitoring and Patient Follow-Up Program at Massachusetts General Hospital

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B. [Massachusetts General Hospital (United States)

    2016-06-15

    Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilities over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.

  10. Individual Monitoring service for occupational exposure in Sudan

    International Nuclear Information System (INIS)

    Suliman, E.E.; Shaddad, I.; Medani, B.E.; Osman, M.Y.

    2005-01-01

    Full text: Individual Monitoring Service (IMS) is a dosimetry service provided by Radiation Protection Department (RPD) of Sudan Atomic Energy Commission (SAEC) to monitor about 400 occupational exposed workers all over the country. Measurements were done using thermoluminescence dosimeters (TLD). The calibration of the TLD system was performed on a phantom with application of suitable correction factors in the SSDL using Cs-137 and different qualities of x-ray energies. Personal dose equivalents Hp(10) and Hp(0.07) were evaluated by employing one individual dosimeter to be carried continuously by the occupational exposed person while at work. In this work the dose received by workers in x-ray diagnostic radiology, radiotherapy, nuclear medicine, research and industrial radiography were evaluated. Radiation doses for the years 1999, 2000, 2001, 2002 and 2003 were compared. From the results obtained, it was noticed that individual monitoring service had expanded over the last years. The average individual annual dose in different applications is less than 1 mSv/y except for the workers in industrial radiography, only 12 radiation workers (3.64 %) received doses exceeding 1 mSv and no individual approached the dose limit of 20 mSv recommended by the ICRP and set by Sudan's regulations. (author)

  11. Forward and backscatter dose profile to diagnostic X-rays at gold/tissue interfaces

    International Nuclear Information System (INIS)

    Rosa, Luiz A.R. da; Seidenbusch, Michael; Regulla, Dieter F.

    1997-01-01

    The radiological and clinical significance of dose distributions in the vicinity of media interfaces in radiotherapy and the complex nature of these dose distributions have long been recognised. A possible dosimetry method for dose profile assessment near interfaces is the use of the so-called thermally stimulated exoelectron emission (TSEE) dosemeter. In this work the possibility of using Be O/TSEE dosimeters to assess the forward and backscatter dose profile at the interface soft tissue/gold was investigated for diagnostic heavily filtered X-rays spectrum A-60 of ISO Standard A-quality. Dose and range profiles are presented. (author). 14 refs., 3 figs

  12. Studies on the gonad dose in x-ray examination for the two day human dock at Nissei Hospital

    International Nuclear Information System (INIS)

    Murakami, Shozo; Muraoka, Tsutomu; Ishigaki, Naoya; Ono, Toshio; Nakai, Toshio

    1979-01-01

    The gonad dose in x-ray examination should be reduced to the minimum extent. The purpose of this study is to estimate the gonad dose in x-ray examination for the two day-human dock at Nissei Hospital. The gonad dose to 40 males and 60 females was measured on cholecystography and gastrointestinal radiography. Dose measurement was performed using a thermoluminescence dosimeter. The results were as follows: Mean gonad dose is 6.9 mR to male and 44.2 mR to female, so that gonad dose to female is 6.4 times greater than that to male. (author)

  13. First-principles X-ray absorption dose calculation for time-dependent mass and optical density.

    Science.gov (United States)

    Berejnov, Viatcheslav; Rubinstein, Boris; Melo, Lis G A; Hitchcock, Adam P

    2018-05-01

    A dose integral of time-dependent X-ray absorption under conditions of variable photon energy and changing sample mass is derived from first principles starting with the Beer-Lambert (BL) absorption model. For a given photon energy the BL dose integral D(e, t) reduces to the product of an effective time integral T(t) and a dose rate R(e). Two approximations of the time-dependent optical density, i.e. exponential A(t) = c + aexp(-bt) for first-order kinetics and hyperbolic A(t) = c + a/(b + t) for second-order kinetics, were considered for BL dose evaluation. For both models three methods of evaluating the effective time integral are considered: analytical integration, approximation by a function, and calculation of the asymptotic behaviour at large times. Data for poly(methyl methacrylate) and perfluorosulfonic acid polymers measured by scanning transmission soft X-ray microscopy were used to test the BL dose calculation. It was found that a previous method to calculate time-dependent dose underestimates the dose in mass loss situations, depending on the applied exposure time. All these methods here show that the BL dose is proportional to the exposure time D(e, t) ≃ K(e)t.

  14. Different gamma ray (60 Co) dose effects on Sorghum genotype germination

    International Nuclear Information System (INIS)

    Tabosa, Jose Nildo; Gomes, Roberto Vicente; Reis, Odemar Vicente dos; Colaco, Waldeciro

    2004-01-01

    In agriculture, applying irradiation is a very valuable way of obtaining vegetable products for human and animal consumption. Cobalt-60, one of the main sources of gamma-rays, is considered an important tool in plant breeding programs, which have the objective of promoting genetic variability of cultivars with resistance to adverse environments. In this research, the effects of different 60 Co doses on germination vigor and seed germination velocity of forage sorghum genotypes were evaluated. The study was carried out at the IPA (Empresa Pernambucana de Pesquisa Agropecuaria) in Recife, Pernambuco, Brazil. The work was installed in germination boxes, following laboratory recommendations. Thus, a experiment involving three sorghum genotypes (IPA 467-4-2, IPA 02-03-01, and Sudan 4202), five 60 Co doses (Zero, 150, 300, 350, and 400 Gy), was set up. The sees were irradiated before the beginning of the experiment being exposed to gamma rays from a 60 Co-source (cobalt irradiator) at DEN (Nuclear Engineering Department) of the UFPE (Pernambuco Federal University), Brazil. The work also had the objective of evaluating the sorghum genotypes x 60 Co dose interaction. The main results obtained showed that the sorghum genotype IPA 02-03-01 presented the greatest values of germination and vigor percentages, and seed germination velocity, when compared to the others evaluated, on 350 and 400 Gy of 60 Co doses. (author)

  15. X-ray facility for the ground calibration of the X-ray monitor JEM-X on board INTEGRAL

    DEFF Research Database (Denmark)

    Loffredo, G.; Pelliciari, C.; Frontera, F.

    2003-01-01

    We describe the X-ray facility developed for the calibration of the X-ray monitor JEM-X on board the INTEGRAL satellite. The apparatus allowed the scanning of the detector geometric area with a pencil beam of desired energy over the major part of the passband of the instrument. The monochromatic...

  16. Personal dose monitoring in hospitals: Global assessment, critical applications and future needs

    International Nuclear Information System (INIS)

    Covens, P.; Berus, D.; Buls, N.; Clerinx, P.; Vanhavere, F.

    2007-01-01

    It is known that medical applications using ionising radiation are wide spread and still increasing. Physicians, technicians, nurses and others constitute the largest group of workers occupationally exposed to man-made sources of radiation. Many hospital workers are consequently subjected to routine monitoring of professional radiation exposures. in the university hospital, UZ Brussel, 600 out of 4000 staff members are daily monitored for external radiation exposures. The most obvious applications of ionising radiation are diagnostic radiology, diagnostic or therapeutic use of radionuclides in nuclear medicine and external radiation therapy or brachytherapy in radiotherapy departments. Other important applications also include various procedures in interventional radiology (IR), in vitro biomedical research and radiopharmaceutical production around cyclotrons. Besides the fact that many of the staff members, involved in these applications, are not measurably exposed, detailed studies were carried out at workplaces where routine dose monitoring encounters difficulties and for some applications where relatively high occupational exposures can be found. most of the studies are concentrated around nuclear medicine applications and IR. They contain assessments of both effective dose and doses at different parts of the body. The results contribute to better characterisation of the different workplaces in a way that critical applications can be identified. Moreover, conclusions point out future needs for practical routine dose monitoring and optimisation of radiation protection. (authors)

  17. Procedures for operational monitoring of the environmental equivalent doses in cobalt therapy

    International Nuclear Information System (INIS)

    Perez Velasquez, Reytel; Gonzalez Lopez, Nadia; Perez Tamayo, Luis

    2009-01-01

    It took as its object of study environmental equivalent dose rates of field radiation they face radiophysicists technicians and medical physicists in the irradiation site of the radiation department of Lenin Hospital in Holguin, and the public that travels or remains in premises and areas surrounding the campus. It A review of national and international publications as well as technical documents to study the state of the art of the methodological existing monitoring of those dose rates and the valuation of impact in the context of an environmental management system. Since no detailed instructions and to perform the above-mentioned monitoring was proposed structure should contain a procedure to regulate the steps for this monitoring in the radiotherapy department of the Lenin Hospital Holguin, for which we studied the guidelines of NC ISO 14000 , and was conducted wide experiment whose led to: illustrate the level of doses required workers exposed occupationally exposed to radiation and the public compare these levels with natural radiation sources, assess the effectiveness of shielding the site of irradiation and the points of greatest risk within and outside the enclosure irradiation.Also assessed the impact it can have on the health of people exposed to such doses. Finally, we proposed a procedure for conducting subsequent monitoring and made recommendations to reduce levels radiation determined the lowest level reasonably achievable. (author)

  18. Yield and Chemical Composition of Cucumber Treated by Nitrogen Levels and Doses of Gamma Rays

    International Nuclear Information System (INIS)

    Fath El-Bab, T.Sh.; Abo El-Khier, Om.M.; Abdallah, A.A.G.

    2013-01-01

    Two field experiments were performed at the Atomic Energy Authority, Experimental farm, Inshas, Egypt during 2010 and 2011 summer growing seasons in sandy soil. The experiments were conducted to study the effect of pre-sowing seeds which treated by gamma irradiation with different doses of 0, 2, 4 and 6 Gy. This was in combination with three rates of nitrogen, fertilizer i.e., 30, 60 and 90 Kg N/fed. The experiments were laid out using drip irrigation system. The obtained results indicated that gamma rays doses showed significant differences on cucumber yield per plot or per Fed., increasing doses of gamma rays gradually increased cucumber yield per plot up to highest dose, i.e., (6 Gy). The highest value of total yield was obtained with the highest nitrogen rate (90 Kg N/fed.). Doses of gamma rays significantly increased total soluble solids (T.S.S.), total Carbohydrates, fats, total protein, NPK and Ca of cucumber fruits. Application of 60 Kg N/fed. recorded the highest values of all above mentioned chemical characters except of total protein with 90 kg N/fed. every all dose treatments. The effect of interaction between doses and fertilizer levels on chemical characters were significant therefore, the highest values was found at 4 Gy and 60 Kg N/fed. treatment for protein, fat, nitrogen and potassium contents while the carbohydrate and calcium contents had the highest value with the treatment of 6 Gy and 60 Kg N/fed

  19. Impact of x-ray dose on the response of CR-39 to 1-5.5 MeV alphas

    International Nuclear Information System (INIS)

    Rojas-Herrera, J.; Rinderknecht, H. G.; Zylstra, A. B.; Gatu Johnson, M.; Orozco, D.; Rosenberg, M. J.; Sio, H.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2015-01-01

    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray uences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-K α and K β x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula

  20. Surface dose of X rays to patients during extracorporeal shock wave lithotripsy

    International Nuclear Information System (INIS)

    Jiang Qingqi; Weng Zhigeng; Feng Ming; Wang Guomin.

    1990-01-01

    During extracorporeal shock wave lithotripsy (ESWL), the fluoroscopy must be made to show the location and size of the stone thus the patient has to be exposed to X rays. The surface dose to patients during ESWL was measured in an investigation on 134 cases of renal lithiasis admitted in a certain hospital of Shanghai. The results show that the average skin dose equivalent for these patients was 162 mSv and the magnitude of doses was depended upon some factors such as the size and location of the stone

  1. Survey on the frequency of typical X-Ray examinations and estimation of associated population doses in the Republic of Macedonia

    International Nuclear Information System (INIS)

    Gershan, V.; Stikova, E.

    2013-01-01

    Purpose: Medical X-ray exposures have been the largest man-made source of population exposure to ionizing radiation in developed countries for many years. It is therefore important for radiation protection and health care authorities in each country to regularly assess the magnitude and the distribution of this large and increasing source of population exposure. The purpose of this paper is to present results from the survey on the number of typical X-ray examination procedures in the Republic of Macedonia for 2010, the distribution of examination procedures by type per modality for adults and pediatric patients, the annual frequency per 1000 population and the collective effective dose per 1000 population from the X-ray examination procedures performed in the Republic of Macedonia in 2010. Materials and methods: In the beginning of 2011, a survey was initiated in the Republic of Macedonia for collecting data on the number of typical X-ray examination procedures conducted in 2010 as a basis for estimating frequency of these procedures and associated population doses. The survey was initiated within a Dose Data Med project launched by the European Commission to study population doses from medical exposures within the Union. The Republic of Macedonia was invited to participate in this project as a test country. Typical X-ray examination procedures encompass those that are recognized to be the most important for the total population dose, referred to as TOP20 X-ray procedures. The survey was based on a specific questionnaire being prepared and distributed to the 87 X-ray departments in the Republic of Macedonia intended to cover the data for the year of 2010. The data was collected and summarized. Based on data gathered, the total number of examination procedures, annual frequency and their distribution by modality were calculated. Thereafter, the annual collective effective dose per 1000 population for each examination procedure in the TOP20 group and collective

  2. Effect of low dose X-ray irradiation on apoptosis in spermatogenic cells of mouse testes

    International Nuclear Information System (INIS)

    Liu Guangwei; Liu Shuchun; Lu Zhe; Gong Shouliang

    2003-01-01

    To study the effects of low dose radiation (LDR) with different doses of X-rays on the apoptosis in spermatogenic cells of male Kunming mouse testes. The time-effect and dose-effect of apoptosis in the different stages of spermatogenic cell cycles of mouse testis after LDR with different doses of X-rays were studied with light microscope using the methods of TdT-mediated dUTP nick end labeling (TUNEL) and HE staining. The apoptosis of spermatogenic cells induced by LDR had a remarkable regularity in cell types. When the dose was 0.025 Gy, spermatogonium apoptosis was taken as main. With the dose increase of irradiation (0.025-0.2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic rate of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarcely occurred after irradiation with low dose. The apoptosis of spermatogenic cells induced by LDR has a regular change, which provides a further experimental evidence for the mechanism study of hormesis by LDR

  3. Using Six Sigma to improve once daily gentamicin dosing and therapeutic drug monitoring performance.

    LENUS (Irish Health Repository)

    Egan, Sean

    2012-08-07

    BACKGROUND: Safe, effective therapy with the antimicrobial gentamicin requires good practice in dose selection and monitoring of serum levels. Suboptimal therapy occurs with breakdown in the process of drug dosing, serum blood sampling, laboratory processing and level interpretation. Unintentional underdosing may result. This improvement effort aimed to optimise this process in an academic teaching hospital using Six Sigma process improvement methodology. METHODS: A multidisciplinary project team was formed. Process measures considered critical to quality were defined, and baseline practice was examined through process mapping and audit. Root cause analysis informed improvement measures. These included a new dosing and monitoring schedule, and standardised assay sampling and drug administration timing which maximised local capabilities. Three iterations of the improvement cycle were conducted over a 24-month period. RESULTS: The attainment of serum level sampling in the required time window improved by 85% (p≤0.0001). A 66% improvement in accuracy of dosing was observed (p≤0.0001). Unnecessary dose omission while awaiting level results and inadvertent disruption to therapy due to dosing and monitoring process breakdown were eliminated. Average daily dose administered increased from 3.39 mg\\/kg to 4.78 mg\\/kg\\/day. CONCLUSIONS: Using Six Sigma methodology enhanced gentamicin usage process performance. Local process related factors may adversely affect adherence to practice guidelines for gentamicin, a drug which is complex to use. It is vital to adapt dosing guidance and monitoring requirements so that they are capable of being implemented in the clinical environment as a matter of routine. Improvement may be achieved through a structured localised approach with multidisciplinary stakeholder involvement.

  4. Measurements of the dose due to cosmic rays in aircraft

    International Nuclear Information System (INIS)

    Vukovic, B.; Lisjak, I.; Radolic, V.; Vekic, B.; Planinic, J.

    2006-01-01

    When the primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The cosmic radiation dose aboard A320 and ATR 42 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; radon concentration in the atmosphere was measured with the Alpha Guard radon detector. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed by the flights Zagreb-Paris-Buenos Aires and reversely, when one measured cosmic radiation dose; for 26.7 h of flight, the TLD dosimeter registered the total dose of 75 μSv and the average dose rate was 2.7 μSv/h. In the same month, February 2005, a traveling to Japan (24 h flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 μSv/h

  5. Measurements of the dose due to cosmic rays in aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Lisjak, I. [Croatia Airlines, Zagreb (Croatia); Radolic, V. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Vekic, B. [Rudjer Boskovic Institute, Zagreb (Croatia); Planinic, J. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia)]. E-mail: planinic@ffos.hr

    2006-06-15

    When the primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The cosmic radiation dose aboard A320 and ATR 42 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; radon concentration in the atmosphere was measured with the Alpha Guard radon detector. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed by the flights Zagreb-Paris-Buenos Aires and reversely, when one measured cosmic radiation dose; for 26.7 h of flight, the TLD dosimeter registered the total dose of 75 {mu}Sv and the average dose rate was 2.7 {mu}Sv/h. In the same month, February 2005, a traveling to Japan (24 h flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 {mu}Sv/h.

  6. 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

  7. Swift X-ray monitoring of stellar coronal variability

    Science.gov (United States)

    Miller, Brendan; Hagen, Cedric; Gallo, Elena; Wright, Jason T.

    2018-01-01

    We used California Planet Search Ca II H and K core emission measurements to identify and characterize chromospheric activity cycles in a sample of main-sequence FGK stars. About a dozen of these with existing ROSAT archival data were targeted with Swift to obtain a current epoch X-ray flux. We find that coronal variability by a factor of several is common on decade-long timescales (we attempt to link to the chromospheric cycle phase) but can also occur on short timescales between Swift visits to a given target, presumably related to stellar rotation and coronal inhomogeneity or to small flares. Additionally, we present new Swift monitoring observations of two M dwarfs with known exoplanets: GJ 15A and GJ 674. GJ 15A b is around 5.3 Earth masses with an 11.4 day orbital period, while GJ 674 is around 11.1 Earth masses with a 4.7 day orbital period. GJ 15A was observed several times in late 2014 and then monitored at approximately weekly intervals for several months in early 2016, for a total exposure of 18 ks. GJ 674 was monitored at approximately weekly intervals for most of 2016, for a total exposure of 40 ks. We provide light curves and hardness ratios for both sources, and also compare to earlier archival X-ray data. Both sources show significant X-ray variability, including between consecutive observations. We quantify the energy distribution for coronal flaring, and compare to optical results for M dwarfs from Kepler. Finally, we discuss the implications of M dwarf coronal activity for exoplanets orbiting within the nominal habitable zone.

  8. The impact of x-ray tube configuration on the eye lens and extremity doses received by cardiologists in electrophysiology room

    International Nuclear Information System (INIS)

    Domienik, J; Zmyślony, M; Bissinger, A

    2014-01-01

    The aim of the study was to analyse the influence of the x-ray tube configuration on the radiation doses to eye lens and extremities of cardiologists performing pacemaker implantation procedures in electrophysiology laboratory. The measurements were performed on one, widely used, portable C-arm system, first with x-ray tube mounted above the patient table and image intensifier below it and then on a reinstalled (but essentially the same) system with under-table x-ray tube configuration. Thermoluminescent dosimeters, placed in various positions near the eye lens, on the hands and ankle, were used during every procedure. The comparison of doses received by cardiologists after changing the x-ray tube configuration from over- to under-table shows statistically significant dose reduction (p < 0.009) for the eye lens closest to the x-ray tube, left finger, left wrist, while for the ankle a dose increase is observed. The corresponding over- to under-table x-ray tube median dose ratios are 4.1 for the right eye, 4.8 for the left finger, 3.0 for left wrist and, finally, 0.13 for the right ankle. Systems with under-table x-ray tube are preferable from a radiation protection point of view. The observed significant increase in doses to the legs should be partially compensated by the use of a protective lead curtain. (note)

  9. Response of the 'patient dose calibrator' chamber for incident positions and sizes of X-ray fields

    International Nuclear Information System (INIS)

    Oliveira, Cassio M.; Abrantes, Marcos Eugenio S.; Ferreira, Flavia C. Bastos; Lacerda, Marco A. de Souza; Alonso, Thessa C.; Silva, Teogenes A. da; Oliveira, Paulo Marcio C.

    2009-01-01

    The evaluation of patient doses is an important tool for optimizing radiodiagnostic medical procedures with conventional X-ray equipment and for improving the quality of the radiographic image. The Patient Dose Calibrator (PDC) chamber is a dosimetric instrument that is used in the evaluation of the air kerma-area product (P KA ) quantity aiming the reduction of patient doses. The objective this work was to study the P KA variation caused by different field incident positions and sizes of the X-ray beam on the PDC chamber. Results showed that the PDC chamber has repeatability lower than 0.6%, beam position dependence of 3% and linearity response within ± 6%; these characteristics are to be taken into account during evaluation of the radiological protection conditions of conventional x-ray equipment. (author)

  10. Estimation of the contribution of neutrons to the equivalent dose for personnel occupationally exposed and public in medical facilities: X-ray with energy equal or greater than 10MV

    International Nuclear Information System (INIS)

    Gonzalez, Alfonso Mayer; Jimenez, Roberto Ortega; Sanchez, Mario A. Reyes; Moranchel y Mejia, Mario

    2013-01-01

    In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and Occupationally Staff Exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents an estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)

  11. VPD residue search by monitoring scattered x-rays

    International Nuclear Information System (INIS)

    Mori, Y.; Yamagami, M.; Yamada, T.

    2000-01-01

    Recently, VPD-TXRF has come into wide use for semiconductor analysis. In VPD-TXRF technique, adjusting the mechanical measuring point to the center of dried residue is of importance for accurate determination. Until now, the following searching methods have been used: monitoring light scattering under bright illumination, using laser scattering particle mapper, applying internal standard as a marker. However, each method has individual disadvantage. For example, interference of Kβ line (ex. Sc-Kβ to Ti-Kα) occurs in the internal standard method. We propose a new searching method 'scattered x-ray search' which utilizes x-ray scattering form the dried residue as a marker. Since the line profile of x-ray scattering agrees with that of fluorescent x-rays, scattered x-ray can be used as an alternative marker instead of internal standard. According to our experimental results, this search method shows the same accuracy as internal standard method. The merits are as follows: 1) no need to add internal standard, 2) rapid search because of high intensity of scattered x-rays, 3) searching software for internal standard can be applied without any modification. In this method, diffraction of incident x-rays by substrate causes irregular change over the detected scattering x-rays. Therefore, this method works better under x-y controlled stage than r-Θ one. (author)

  12. LOBSTER EYE: New approach to monitor GRBs in X-rays

    International Nuclear Information System (INIS)

    Hudec, R.; Hudcova, V.; Inneman, A.; Pina, L.

    2003-01-01

    The detection of X-ray afterglows for the large majority of GRBs allows a novel X-ray experiment to be considered to monitor and to detect GRBs based on their X-ray emission. Such an experiment could provide not only a superior localization accuracy if compared with gamma ray instruments, but probably also a higher rate based on the theoretical assumption that the beaming in gamma rays is narrower if compared with lower energies. We describe and discuss the LOBSTER EYE X-ray telescope project including results of the development and tests of the telescope prototype. Considerations for a space experiment on a small scientific satellite of a Nadezhda type are also presented and discussed. The scientific aspects of such experiment regarding the GRB study and statistics are addressed

  13. Historical building monitoring by means of a cosmic ray tracking system

    International Nuclear Information System (INIS)

    Zenoni, Aldo

    2015-01-01

    Cosmic ray radiation is mostly composed, at sea level, by high energy muons, which are highly penetrating particles capable of crossing kilometers of rock. The ubiquitous and steady presence at the Earth's surface and the high penetration capability have motivated the use of cosmic ray radiation also in fields beyond particle physics, from geology, archaeology, speleology to industrial applications and homeland security. In particular, in recent years, the novel technique of muon tomography has been proposed, with the aim of performing non invasive inspection of large non accessible volumes, material atomic number Z and density discrimination, and three dimension image reconstruction of the inspected volume. In the present paper, after a short recall of the physical principles and mathematical formalism on which muon tomography is based, a number of examples of application of the novel technique in industry and homeland security issues is given. Moreover, a new application of cosmic rays detection techniques in the field of civil engineering is proposed. The aim is the monitoring of the stability of large structures, in particular the static monitoring of historical buildings, where conservation constraints are more severe and the time evolution of the deformation phenomena under study may be of the order of months or years. The new technique may be seen, in some way, as the reverse problem of muon tomography. As a significant case study, the monitoring of the wooden vaulted roof of the Palazzo della Loggia in the town of Brescia, in Italy, has been considered. The feasibility as well as the performances and limitations of a monitoring system based on cosmic ray tracking have been studied by Monte Carlo simulation and discussed in comparison with more traditional monitoring systems. (authors)

  14. Historical building monitoring by means of a cosmic ray tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Zenoni, Aldo [Department of Mechanical and Industrial Engineering of the University of Brescia, Via Branze 38, 25123 Brescia, (Italy); INFN Sezione di Pavia, Via Bassi 6, 27100 Pavia, (Italy)

    2015-07-01

    Cosmic ray radiation is mostly composed, at sea level, by high energy muons, which are highly penetrating particles capable of crossing kilometers of rock. The ubiquitous and steady presence at the Earth's surface and the high penetration capability have motivated the use of cosmic ray radiation also in fields beyond particle physics, from geology, archaeology, speleology to industrial applications and homeland security. In particular, in recent years, the novel technique of muon tomography has been proposed, with the aim of performing non invasive inspection of large non accessible volumes, material atomic number Z and density discrimination, and three dimension image reconstruction of the inspected volume. In the present paper, after a short recall of the physical principles and mathematical formalism on which muon tomography is based, a number of examples of application of the novel technique in industry and homeland security issues is given. Moreover, a new application of cosmic rays detection techniques in the field of civil engineering is proposed. The aim is the monitoring of the stability of large structures, in particular the static monitoring of historical buildings, where conservation constraints are more severe and the time evolution of the deformation phenomena under study may be of the order of months or years. The new technique may be seen, in some way, as the reverse problem of muon tomography. As a significant case study, the monitoring of the wooden vaulted roof of the Palazzo della Loggia in the town of Brescia, in Italy, has been considered. The feasibility as well as the performances and limitations of a monitoring system based on cosmic ray tracking have been studied by Monte Carlo simulation and discussed in comparison with more traditional monitoring systems. (authors)

  15. Dose absorbed in x-rays toraxicas executed in hospitals of the city of Sao Paulo Brazil

    International Nuclear Information System (INIS)

    Freitas, M.B.; Yoshimura, E.M.

    1998-01-01

    With the objective of evaluating the contribution of radiography exams in the dose received by the population of the city of Sao Paulo (Brazil), we made mensurations of the doses absorbed in toraxicas x-rays (projections PA and LAT) taken in several teams of rays X used in hospitals. The work is supplemented with demography data and the knowledge of the quantity of exams executed in each team

  16. Equally sloped X-ray microtomography of living insects with low radiation dose and improved resolution capability

    International Nuclear Information System (INIS)

    Yao, Shengkun; Fan, Jiadong; Zong, Yunbing; Sun, Zhibin; Zhang, Jianhua; Jiang, Huaidong; He, You; Zhou, Guangzhao; Xiao, Tiqiao; Huang, Qingjie

    2016-01-01

    Three-dimensional X-ray imaging of living specimens is challenging due to the limited resolution of conventional absorption contrast X-ray imaging and potential irradiation damage of biological specimens. In this letter, we present microtomography of a living specimen combining phase-contrast imaging and a Fourier-based iterative algorithm termed equally sloped tomography. Non-destructive 3D imaging of an anesthetized living yellow mealworm Tenebrio molitor was demonstrated with a relatively low dose using synchrotron generated X-rays. Based on the high-quality 3D images, branching tracheoles and different tissues of the insect in a natural state were identified and analyzed, demonstrating a significant advantage of the technique over conventional X-ray radiography or histotomy. Additionally, the insect survived without problem after a 1.92-s X-ray exposure and subsequent absorbed radiation dose of ∼1.2 Gy. No notable physiological effects were observed after reviving the insect from anesthesia. The improved static tomographic method demonstrated in this letter shows advantage in the non-destructive structural investigation of living insects in three dimensions due to the low radiation dose and high resolution capability, and offers many potential applications in biological science.

  17. Equally sloped X-ray microtomography of living insects with low radiation dose and improved resolution capability

    Science.gov (United States)

    Yao, Shengkun; Fan, Jiadong; Zong, Yunbing; He, You; Zhou, Guangzhao; Sun, Zhibin; Zhang, Jianhua; Huang, Qingjie; Xiao, Tiqiao; Jiang, Huaidong

    2016-03-01

    Three-dimensional X-ray imaging of living specimens is challenging due to the limited resolution of conventional absorption contrast X-ray imaging and potential irradiation damage of biological specimens. In this letter, we present microtomography of a living specimen combining phase-contrast imaging and a Fourier-based iterative algorithm termed equally sloped tomography. Non-destructive 3D imaging of an anesthetized living yellow mealworm Tenebrio molitor was demonstrated with a relatively low dose using synchrotron generated X-rays. Based on the high-quality 3D images, branching tracheoles and different tissues of the insect in a natural state were identified and analyzed, demonstrating a significant advantage of the technique over conventional X-ray radiography or histotomy. Additionally, the insect survived without problem after a 1.92-s X-ray exposure and subsequent absorbed radiation dose of ˜1.2 Gy. No notable physiological effects were observed after reviving the insect from anesthesia. The improved static tomographic method demonstrated in this letter shows advantage in the non-destructive structural investigation of living insects in three dimensions due to the low radiation dose and high resolution capability, and offers many potential applications in biological science.

  18. Equally sloped X-ray microtomography of living insects with low radiation dose and improved resolution capability

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shengkun; Fan, Jiadong; Zong, Yunbing; Sun, Zhibin; Zhang, Jianhua; Jiang, Huaidong, E-mail: hdjiang@sdu.edu.cn [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); He, You; Zhou, Guangzhao; Xiao, Tiqiao [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Huang, Qingjie [School of Information Science and Engineering, Shandong University, Jinan 250100 (China)

    2016-03-21

    Three-dimensional X-ray imaging of living specimens is challenging due to the limited resolution of conventional absorption contrast X-ray imaging and potential irradiation damage of biological specimens. In this letter, we present microtomography of a living specimen combining phase-contrast imaging and a Fourier-based iterative algorithm termed equally sloped tomography. Non-destructive 3D imaging of an anesthetized living yellow mealworm Tenebrio molitor was demonstrated with a relatively low dose using synchrotron generated X-rays. Based on the high-quality 3D images, branching tracheoles and different tissues of the insect in a natural state were identified and analyzed, demonstrating a significant advantage of the technique over conventional X-ray radiography or histotomy. Additionally, the insect survived without problem after a 1.92-s X-ray exposure and subsequent absorbed radiation dose of ∼1.2 Gy. No notable physiological effects were observed after reviving the insect from anesthesia. The improved static tomographic method demonstrated in this letter shows advantage in the non-destructive structural investigation of living insects in three dimensions due to the low radiation dose and high resolution capability, and offers many potential applications in biological science.

  19. SSD effects on high energy x-ray surface and build up dose

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: Dose in the build up region for high energy x-rays produced by a medical linear accelerator is affected by the x-ray source to patient surface distance (SSD). The use of isocentric treatments whereby the tumour is positions 100cm from the source means that depending of the depth of the tumour and the size of the patient, the SSD can vary from distances of 80cm to 100cm. To achieve larger field sizes, the SSD can also be extended out to 120cm at times. Results have shown that open fields are not significantly affected by SSD changes with deviations in percentage dose being less than 4% of maximum dose for SSD's from 80cm to 120cm SSD. With the introduction of beam modifying devices such as Perspex blocking trays, the effects are significant with a deviation of up to 22% measured at 6MV energy with a 6mm Perspex tray for SSD's from 80cm to 120cm. These variations are largest at the skin surface and reduce with depth. The use of a multi leaf collimator for blocking removes extra skin dose caused by the Perspex block trays with decreasing SSD. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  20. Impact of thermoplastic mask on X-ray surface dose calculated with Monte Carlo code

    International Nuclear Information System (INIS)

    Zhao Yanqun; Li Jie; Wu Liping; Wang Pei; Lang Jinyi; Wu Dake; Xiao Mingyong

    2010-01-01

    Objective: To calculate the effects of thermoplastic mask on X-ray surface dose. Methods: The BEAMnrc Monte Carlo Code system, designed especially for computer simulation of radioactive sources, was performed to evaluate the effects of thermoplastic mask on X-ray surface dose.Thermoplastic mask came from our center with a material density of 1.12 g/cm 2 . The masks without holes, with holes size of 0.1 cm x 0.1 cm, and with holes size of 0. 1 cm x 0.2 cm, and masks with different depth (0.12 cm and 0.24 cm) were evaluated separately. For those with holes, the material width between adjacent holes was 0.1 cm. Virtual masks with a material density of 1.38 g/cm 3 without holes with two different depths were also evaluated. Results: Thermoplastic mask affected X-rays surface dose. When using a thermoplastic mask with the depth of 0.24 cm without holes, the surface dose was 74. 9% and 57.0% for those with the density of 1.38 g/cm 3 and 1.12 g/cm 3 respectively. When focusing on the masks with the density of 1.12 g/cm 3 , the surface dose was 41.2% for those with 0.12 cm depth without holes; 57.0% for those with 0. 24 cm depth without holes; 44.5% for those with 0.24 cm depth with holes size of 0.1 cm x 0.2 cm;and 54.1% for those with 0.24 cm depths with holes size of 0.1 cm x 0.1 cm.Conclusions: Using thermoplastic mask during the radiation increases patient surface dose. The severity is relative to the hole size and the depth of thermoplastic mask. The surface dose change should be considered in radiation planning to avoid severe skin reaction. (authors)

  1. Effects of low dose gamma-ray radiation on the seed germination and physiological activity of vegetable crops

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Baek, M. H.; Lee, Y. G. [KAERI, Taejon (Korea, Republic of); Jung, K. H. [Kyunghee Univ., Yongin (Korea, Republic of)

    2000-10-01

    To determine the effect of low dose gamma-ray radiation on the germination rate and physiology of germinative seeds of Chinese cabbage(Brassica campestris L. cv. Hanyoreum) and radish(Raphanus sativus L. cv. Chungsukoungzoung). The germination rate of irradiation group was higher than that of the control. Especially it was highest at the early stage of induction. The germination rate of Chinese cabbage increased at 4 Gy-, 10 Gy- and 50 Gy irradiation group and that of radish increased at 2 Gy-, 6 Gy- and 10 Gy irradiation group. The seedling height of Chinese cabbage and radish increased positively in low dose irradiation group. The seedling height of Chinese cabbage was noticeably higher at 4 Gy and 10 Gy irradiation group and that of radish at 6 Gy irradiation group. The protein contents of seeds irradiated with low dose gamma-ray radiation was increased compared to that of the control especially at the early stage of induction. The enzyme activity of seeds irradiated with low dose of gamma-ray radiation was increased at 4 Gy and 10 Gy irradiation group. These results suggest that the germination and physiological activity of old seeds could be stimulated promisingly by the low dose gamma-ray radiation.

  2. Cytosolic Hsp70/Hsc70 protein expression in lymphocytes exposed to low gamma-ray dose

    International Nuclear Information System (INIS)

    Manzanares A, E.; Vega C, H.R.; Letechipia de Leon, C.; Guzman E, L.J.; Garcia T, M.

    2004-01-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp70 expression in human Iymphocytes. The heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. When a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered only through over expression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the Iymphocytes were isolated by ficoll- histopaque gradient. Experimental lots were irradiated in a 137 Cs gamma-ray. Hsp70 expression was found since 0.5 c Gy, indicating a threshold to very low doses of gamma rays. (Author)

  3. Cytosolic Hsp70/Hsc70 protein expression in lymphocytes exposed to low gamma-ray dose

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares A, E.; Vega C, H.R.; Letechipia de Leon, C. [Unidades Academicas de Estudios Nucleares, UAZ, A.P. 336, 98000 Zacatecas (Mexico)]. E-mail: emanz@cantera.reduaz.mx; Guzman E, L.J. [Unidad Academica de Biologia Experimental, Guadalupe, Zacatecas (Mexico); Garcia T, M. [LIBRA, Centro I and D, Campus Miguel Delibes, Valladolid 47011 (Spain)

    2004-07-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp70 expression in human Iymphocytes. The heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. When a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered only through over expression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the Iymphocytes were isolated by ficoll- histopaque gradient. Experimental lots were irradiated in a {sup 137} Cs gamma-ray. Hsp70 expression was found since 0.5 c Gy, indicating a threshold to very low doses of gamma rays. (Author)

  4. Dose record keeping: a multi purpose tool in individual monitoring

    International Nuclear Information System (INIS)

    Bermann, F.; Julius, H.W.

    1993-01-01

    Proper recording of radiation doses is an essential part of the process of individual monitoring and shares in the same objective. A dose record keeping system is more than just a computer based data storage system and should rather be a Dose Registration and Information System (DRIS). Objectives of dose record keeping are given. As a result of the integration of member states of the European Communities, co-operation and exchange of personnel between countries will be increasing. This will probably require national dose registration systems and adequate data communication between them. These developments emphasize the necessity for international harmonization of dose record keeping systems and categorization of the data they contain. General characteristics and specific aspects of dose record keeping systems will be dealt with. Attention will also be given to some special applications of the recorded information, such as: the use of data for epidemiological studies and for QA purposes. (authors). 5 tabs., 4 refs

  5. Effect of Low Dose gamma-ray Irradiation on the Germination and Growth in Red Pepper (Capcicum annuum L.)

    International Nuclear Information System (INIS)

    Lee Eun-Kyung; Kim Jae-Sung

    1998-01-01

    This study was conducted to determine the effect of low dose gamma-ray irradiation in red pepper. The germination percentage, plant, the number of flower, chlorophyll contents, leaf length and width were observed from plants grown with red pepper seeds irradiated with various low dose of gamma-ray. The germination percentage of irradiation group treatmented gamma-ray was much higher than that of the control. Specially the germination percentage after sowing red pepper seeds on paper towel was higher than 1,000 and 2,000 rad irradiation group. The height of plants grown with red pepper seeds irradiated with gamma-ray was increased in 100, 200 and 400 rad irradiation group compared to that of the control. The height of plant from 2,400 rad irradiation group, however, was shorter than that of the control. Nutrient contents of leaves of plants grown with red pepper seeds irradiated with various dose of gamma-ray were significantly increased in 800 and 1,200 rad irradiation group. Electric conductivity (EC) of the water used for seed germination was lower irradiation group than control group. Therefore, there was the possibility to increase the germination and plant growth with gamma-ray of adequate low dose

  6. Radioactivities (dose rates) of rocks in Japan

    International Nuclear Information System (INIS)

    Matsuda, Hideharu; Minato, Susumu

    1995-01-01

    The radioactive distribution (radiation doses) of major rocks in Japan was monitored to clarify the factors influencing terrestrial gamma-ray absorbed dose rates. The rock samples were reduced to powder and analyzed by well-type NaI(Tl) scintillation detector and pulse height analyzer. Terrestrial gamma-ray dose rates were estimated in terms of gamma radiation dose rate 1 m above the ground. The radioactivity concentration was highest in acidic rock which contains much SiO 2 among igneous rock, followed by neutral rock, basic rock, and ultrabasic rock. The radioactive concentration was 30-40% lower in acidic and clastic rocks than those of the world average concentration. Higher radioactive concentration was observed in soils than the parent rocks of sedimentary rock and metamorphic rock. The gamma radiation dose rate was in proportion to the radioactive concentration of the rocks. To clarify the radioactive effect in the change course of rocks into soils, comparative measurement of outcrop and soil radioactive concentrations is important. (S.Y.)

  7. Provision of dosimeters by official monitoring services for eye lens dose estimation

    International Nuclear Information System (INIS)

    Engelhardt, J.; Martini, E.

    2013-01-01

    Recent epidemiological studies are implying that the radio sensitivity of the eye lens is much higher than supposed in the past. International recommendations and standards demand to lower down the annual limit of the eye lens organ dose to 20 mSv. Since about 10 years German monitoring services offer partial-body dosimeters fixed on the head or on glasses for monitoring the eye lens dose. These dosimeters are optimized to measure the (surface) personal dose equivalent H p (0,07) from 0,5 mSv up to 10 Sv, which clearly overestimate the organ dose of the eye lens. With special features like different calibrations partial-body dosimeters should be applicable for legal dosimetry to avoid the development of special H p (3) dosimeters. Accepting the right way for wearing these dosimeters it is important to get the right results. Practical experiences are shown with measuring results and the difficulties of rounding the exact measuring values to discrete dose steps. Closing this article we point to still missing legal basis and open questions regarding to type testing procedures. (orig.)

  8. MO-FG-202-08: Real-Time Monte Carlo-Based Treatment Dose Reconstruction and Monitoring for Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Z; Shi, F; Gu, X; Tan, J; Hassan-Rezaeian, N; Jiang, S; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States); Graves, Y [University of California, San Diego, La Jolla, CA (United States)

    2016-06-15

    Purpose: This proof-of-concept study is to develop a real-time Monte Carlo (MC) based treatment-dose reconstruction and monitoring system for radiotherapy, especially for the treatments with complicated delivery, to catch treatment delivery errors at the earliest possible opportunity and interrupt the treatment only when an unacceptable dosimetric deviation from our expectation occurs. Methods: First an offline scheme is launched to pre-calculate the expected dose from the treatment plan, used as ground truth for real-time monitoring later. Then an online scheme with three concurrent threads is launched while treatment delivering, to reconstruct and monitor the patient dose in a temporally resolved fashion in real-time. Thread T1 acquires machine status every 20 ms to calculate and accumulate fluence map (FM). Once our accumulation threshold is reached, T1 transfers the FM to T2 for dose reconstruction ad starts to accumulate a new FM. A GPU-based MC dose calculation is performed on T2 when MC dose engine is ready and a new FM is available. The reconstructed instantaneous dose is directed to T3 for dose accumulation and real-time visualization. Multiple dose metrics (e.g. maximum and mean dose for targets and organs) are calculated from the current accumulated dose and compared with the pre-calculated expected values. Once the discrepancies go beyond our tolerance, an error message will be send to interrupt the treatment delivery. Results: A VMAT Head-and-neck patient case was used to test the performance of our system. Real-time machine status acquisition was simulated here. The differences between the actual dose metrics and the expected ones were 0.06%–0.36%, indicating an accurate delivery. ∼10Hz frequency of dose reconstruction and monitoring was achieved, with 287.94s online computation time compared to 287.84s treatment delivery time. Conclusion: Our study has demonstrated the feasibility of computing a dose distribution in a temporally resolved fashion

  9. Fieldable computer system for determining gamma-ray pulse-height distributions, flux spectra, and dose rates from Little Boy

    International Nuclear Information System (INIS)

    Moss, C.E.; Lucas, M.C.; Tisinger, E.W.; Hamm, M.E.

    1984-01-01

    Our system consists of a LeCroy 3500 data acquisition system with a built-in CAMAC crate and eight bismuth-germanate detectors 7.62 cm in diameter and 7.62 cm long. Gamma-ray pulse-height distributions are acquired simultaneously for up to eight positions. The system was very carefully calibrated and characterized from 0.1 to 8.3 MeV using gamma-ray spectra from a variety of radioactive sources. By fitting the pulse-height distributions from the sources with a function containing 17 parameters, we determined theoretical repsonse functions. We use these response functions to unfold the distributions to obtain flux spectra. A flux-to-dose-rate conversion curve based on the work of Dimbylow and Francis is then used to obtain dose rates. Direct use of measured spectra and flux-to-dose-rate curves to obtain dose rates avoids the errors that can arise from spectrum dependence in simple gamma-ray dosimeter instruments. We present some gamma-ray doses for the Little Boy assembly operated at low power. These results can be used to determine the exposures of the Hiroshima survivors and thus aid in the establishment of radation exposure limits for the nuclear industry

  10. Estimation of doses to patients with chronic radiation sickness from external occupational exposure

    International Nuclear Information System (INIS)

    Jia Delin; Dai Guangfu

    1991-01-01

    The doses to patients with chronic radiation sickness who had engaged in diagnostic radiology have been estimated according to the radiation work load, type and capacity of X-ray equipment, protection conditions, data of nationwide survey on doses to X-ray workers in China, or the data of dose monitoring in working places. Based on the activities of radium sources, time taken up in performing radium therapy, distance to radium sources and radiation work load, the doses to patients who had engaged in radium therapy have been estimated. The results of estimated average doses for 29 cases of chronic radiation sickness are given. Their average red marrow dose, trunk dose and effective dose equivalent are 1.3 Gy, 1.2 Gy and 1.6 Sv, respectively

  11. Survey of radiation doses and health effects in medical diagnostic X-ray workers in China

    International Nuclear Information System (INIS)

    Wang Jixian; Zhang Liangan; Liu Jinzhong; Zhang Jingyuan

    1984-01-01

    The results of a nationwide survey of radiation doses and health effects in 26983 medical diagnostic X-ray workers in 28 provinces of China were reported. The control group was composed of 25785 non-X-ray medical workers in the same hospitals where the investigated X-ray workers worked. Of the radiological workers surveyed 75.3% received cumulative radiation doses below 50 mGy, only 2.7% received doses greater than 500 mGy, the average cumulative dose being 45.0 mGy. The average length of service was 11 years. The main radiation effects relating to radiation doses were the increase of frequencies of both chromosomal aberrations and micronuclei in peripheral blood lymphocytes, which were 0.362% and 0.0358% in the irradiated group, and 0.122% and 0.0138% in the control group, respectively. The incidence and mortality rate of leukemias increased significantly in the irradiated group. The incidence and standardized incidence of leukemias were 9.61 . 10 -5 and 9.67 . 10 -5 in the irradiated group and 2.74 . 10 -5 and 2.77 . 10 -5 in the control group. The leukemia mortality rates in the two groups were 8.60 . 10 -5 and 1.24 . 10 -5 respectively, and the standardized mortality rates were 8.60 . 10 -5 and 1.27 . 10 -5 respectively. (Author)

  12. Differential dose albedo for high-energy X-rays on concrete slab

    International Nuclear Information System (INIS)

    Kato, Hideki

    2006-01-01

    We computed the differential dose albedo (α D ) for high-energy X-rays on a concrete slab when the incident angle, reflection angle, and azimuth angle were changed, by means of Monte Carlo simulation. We found that α D changed with incident, reflection, and azimuth angles to the concrete slab. On the whole, the larger the incident angle, the larger α D tended to become. If the incident angle and reflection angle were the same, the larger the azimuth angle, the smaller α D tended to become. When the incident, reflection, and azimuth angles were the same, the smaller the X-ray energy was, the larger α D became, in the order of 10 MV, 6 MV, and 4 MV X-rays. (author)

  13. X-ray irradiation of yeast cells

    Science.gov (United States)

    Masini, Alessandra; Batani, Dimitri; Previdi, Fabio; Conti, Aldo; Pisani, Francesca; Botto, Cesare; Bortolotto, Fulvia; Torsiello, Flavia; Turcu, I. C. Edmond; Allott, Ric M.; Lisi, Nicola; Milani, Marziale; Costato, Michele; Pozzi, Achille; Koenig, Michel

    1997-10-01

    Saccharomyces Cerevisiae yeast cells were irradiated using the soft X-ray laser-plasma source at Rutherford Laboratory. The aim was to produce a selective damage of enzyme metabolic activity at the wall and membrane level (responsible for fermentation) without interfering with respiration (taking place in mitochondria) and with nuclear and DNA activity. The source was calibrated by PIN diodes and X-ray spectrometers. Teflon stripes were chosen as targets for the UV laser, emitting X-rays at about 0.9 keV, characterized by a very large decay exponent in biological matter. X-ray doses to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. After irradiation, the selective damage to metabolic activity at the membrane level was measured by monitoring CO2 production with pressure silicon detectors. Preliminary results gave evidence of pressure reduction for irradiated samples and non-linear response to doses. Also metabolic oscillations were evidenced in cell suspensions and it was shown that X-ray irradiation changed the oscillation frequency.

  14. Development of autonomous gamma dose logger for environmental monitoring.

    Science.gov (United States)

    Jisha, N V; Krishnakumar, D N; Surya Prakash, G; Kumari, Anju; Baskaran, R; Venkatraman, B

    2012-03-01

    Continuous monitoring and archiving of background radiation levels in and around the nuclear installation is essential and the data would be of immense use during analysis of any untoward incidents. A portable Geiger Muller detector based autonomous gamma dose logger (AGDL) for environmental monitoring is indigenously designed and developed. The system operations are controlled by microcontroller (AT89S52) and the main features of the system are software data acquisition, real time LCD display of radiation level, data archiving at removable compact flash card. The complete system operates on 12 V battery backed up by solar panel and hence the system is totally portable and ideal for field use. The system has been calibrated with Co-60 source (8.1 MBq) at various source-detector distances. The system is field tested and performance evaluation is carried out. This paper covers the design considerations of the hardware, software architecture of the system along with details of the front-end operation of the autonomous gamma dose logger and the data file formats. The data gathered during field testing and inter comparison with GammaTRACER are also presented in the paper. AGDL has shown excellent correlation with energy fluence monitor tuned to identify (41)Ar, proving its utility for real-time plume tracking and source term estimation.

  15. A beta skin dose monitor using an Eberline RO-2 ion chamber

    International Nuclear Information System (INIS)

    Jester, W.A.; Levine, S.H.; Lin, T.J.; Hock, R.

    1994-01-01

    The authors have developed a portable beta skin dose monitor that uses an Eberline RO-2trademark ion chamber. The development was based, in part, upon the previous development of a beta skin dose monitor employing silicon detectors. In this current work, the two entrance windows of the RO-2 were replaced by windows having a total mass thickness of 1.74 mg/cm 2 . A two section source-detector holder was constructed. One section fastens to the RO-2 and holds the detector at the right position to determine the contact skin dose from beta emitters located on surfaces. A second section attaches to the first, and provides fixed counting geometry for radioactive samples such as hot particles. The first section also contains a slide mechanism that allows the placement of absorbers of zero (0), 8.38, and 1000 mg/cm 2 between the detector window and the beta source. The detector response to these absorbers allows for the determination of beta skin dose. The system was modeled using a Monte Carlo beta attenuation code computing the beta skin dose to RO-2 detector response as a function of absorber thickness, average beta energy, source diameter and source position. Using the RO-2 reading from each of the three absorber configurations allows the calculation of beta skin dose and the average beta energy. The results of these calculations were confirmed through the use of three massless radioactive beta sources, traceable to the National Institute of Standards and Technology, and several utility-supplied hot particles having well-established contact skin doses. An extrapolation chamber was also used to confirm the results obtained from this monitor. This system is now use at the Pennsylvania Power and Light (PP and L) Company, the project sponsor. ((orig.))

  16. Determination of gamma ray doses suitable for mutation induction in garlic (Allium sativum L.)

    International Nuclear Information System (INIS)

    Al-Safadi, Bassam; Ayyoubi, Zouhair

    1993-04-01

    Garlic (Allium sativum L.) cloves were exposed to different doses of gamma radiation (Control, 100, 250, 500, 750, and 1000 rads). The cloves were planted in 4 replicates at Deer Alhajar station of the Dept. of Radiation Agriculture. Number of surviving plants was recorded at 2 months after planting and at harvest. Length of foliage was measured at harvest time and weight of cloves was taken two weeks after harvest. Visual readings in the field on plant shape and leaf color were also taken. The results indicated a negative effect of gamma radiation on plant survival especially at doses of 750 and 1000 rads where no plants survived until harvest. Plant length and clove weight were reduced even at 500 rad dose. Percentage of yellow and necrotic plants increased with increasing gamma ray dosage. No stimulation of plant growth was noticed as a result of irradiation with low doses of gamma rays. Treatment with 500 rads of gamma radiation was considered the best among tested doses for garlic mutagenesis (Using cloves) since it gave acceptable rate of survival and morphologic variation. (author). 14 refs., 4 figs

  17. A nanovehicle developed for treating deep-seated bacteria using low-dose X-ray.

    Science.gov (United States)

    Pan, Chien-Lin; Chen, Ming-Hong; Tung, Fu-I; Liu, Tse-Ying

    2017-01-01

    Many non-antibiotic strategies, such as photocatalysis and photodynamic therapy, have been proposed to inhibit and/or kill bacteria. However, these approaches still have drawbacks such as insufficient bacterial specificity and the limited penetration depth of ultraviolet and near-infrared light. To overcome these limitations, we developed a bacteria-specific anti-bacterial technique via using low-dose X-ray. Graphene oxide quantum dots (GQDs, a multifunctional vehicle) conjugated with vancomycin (Van, a bacteria-targeting ligand) were assembled with Protoporphyrin IX (PpIX, a photo/radiation sensitizer) to yield a novel Van-GQDs/PpIX complex that specifically attached to Escherichia coli and efficiently generated intracellular reactive oxygen species following X-ray activation. Delivery using GQDs increased the PpIX/Van ratio in the target bacterial cell, damaged bacterial cell wall, and enhanced X-ray-induced PpIX activation. Hence, this approach allowed for the use of a low-dose X-ray to efficiently activate the Van-GQDs/PpIX complex to exert its bactericidal effects on Escherichia coli without damaging normal cells. Furthermore, the E. coli did not develop resistance to the proposed approach for at least 7 rounds of repeated administration during one week. Thus, this proposed vehicle exhibiting bacteria-specific X-ray-triggered toxicity is a promising alternative to antibiotics for treating serious bacterial infections occurring in deep-seated tissues/organs (e.g., osteomyelitis and peritonitis). Administration of antibiotics is the most common treatment modality for bacterial infections. However, in some cases, patient attributes such as age, health, tolerance to antibiotics do not allow for the use of high-dose antibiotics. In addition, some bacteria develop resistance to antibiotics because of improper and long-term use of these agents. Therefore, non-antibiotic strategies to treat deeply situated bacterial infections, such as osteomyelitis, are urgently

  18. Longterm monitoring of ambient dose equivalent rates at aviation altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Heber, B.; Burmeister, S.; Moeller, T.; Scharrenberg, E. [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, Kiel (Germany); Briese, J. [Deutsche Lufthansa AG, Frankfurt am Main (Germany); Burda, O.; Klages, T.; Langner, F.; Marquardt, J.; Wissmann, F. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig Germany (Germany); Matthiae, D.; Reitz, G. [German Aerospace Center, Institute of Aerospace Medicine, Linder Hoehe, 51147 Koeln (Germany)

    2012-07-01

    The complex radiation field at flight altitudes results mainly from the interaction of energetic charged particles with atmospheric molecules and atoms and consists of secondary neutrons, protons, gamma rays, electrons, positrons and muons. Due to the continuous interactions of primary and secondary particles within the atmosphere, the intensity of each component depends on the height. Since the Earth's magnetic field acts as rigidity filter for the charged primary particles, the flux of the primary particles into the atmosphere and the resulting intensity of secondary particles depend on the geomagnetic latitude being highest over the geomagnetic poles. The main primary component consists of Galactic Cosmic Rays (GCRs), mainly protons and alpha particles, whose flux is modulated in the heliosphere. Beside this slowly varying galactic component, solar energetic particle events may temporarily increase the intensity of this radiation field. In the frame of the Radiation Monitoring on Board Aircraft (RAMONA) collaboration, three NAVIgation and DOSimetry (NAVIDOS) systems were installed in 2008 and 2009 on board of three Lufthansa Airbus A340 aircraft. They have been maintained since then by the consortium. Two of the NAVIDOS units rely on the DOSimetry TELescopes (DOSTELs), one is based on a LIULIN detector. This unique setup is ideally suited to investigate variations in the radiation field at different flight altitudes and geomagnetic positions and has been used to measure the radiation exposure during the recent extended solar minimum and thereafter. With increasing solar activity in 2010 the measured dose rates have been decreasing. Since these variations depend on the location of the aircraft, a detailed data analysis is required and presented.

  19. Impact of x-ray dose on track formation and data analysis for CR-39-based proton diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Rinderknecht, H. G., E-mail: rinderknecht1@llnl.gov; Rojas-Herrera, J.; Zylstra, A. B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Séguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Filkins, T.; Steidle, Jessica A.; Traynor, N.; Freeman, C. [State University of New York at Geneseo, Geneseo, New York 14454 (United States); Steidle, Jeffrey A. [Rochester Institute of Technology, Rochester, New York 14623 (United States)

    2015-12-15

    The nuclear track detector CR-39 is used extensively for charged particle diagnosis, in particular proton spectroscopy, at inertial confinement fusion facilities. These detectors can absorb x-ray doses from the experiments in the order of 1–100 Gy, the effects of which are not accounted for in the previous detector calibrations. X-ray dose absorbed in the CR-39 has previously been shown to affect the track size of alpha particles in the detector, primarily due to a measured reduction in the material bulk etch rate [Rojas-Herrera et al., Rev. Sci. Instrum. 86, 033501 (2015)]. Similar to the previous findings for alpha particles, protons with energies in the range 0.5–9.1 MeV are shown to produce tracks that are systematically smaller as a function of the absorbed x-ray dose in the CR-39. The reduction of track size due to x-ray dose is found to diminish with time between exposure and etching if the CR-39 is stored at ambient temperature, and complete recovery is observed after two weeks. The impact of this effect on the analysis of data from existing CR-39-based proton diagnostics on OMEGA and the National Ignition Facility is evaluated and best practices are proposed for cases in which the effect of x rays is significant.

  20. Impact of x-ray dose on track formation and data analysis for CR-39-based proton diagnostics

    International Nuclear Information System (INIS)

    Rinderknecht, H. G.; Rojas-Herrera, J.; Zylstra, A. B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Séguin, F. H.; Petrasso, R. D.; Filkins, T.; Steidle, Jessica A.; Traynor, N.; Freeman, C.; Steidle, Jeffrey A.

    2015-01-01

    The nuclear track detector CR-39 is used extensively for charged particle diagnosis, in particular proton spectroscopy, at inertial confinement fusion facilities. These detectors can absorb x-ray doses from the experiments in the order of 1–100 Gy, the effects of which are not accounted for in the previous detector calibrations. X-ray dose absorbed in the CR-39 has previously been shown to affect the track size of alpha particles in the detector, primarily due to a measured reduction in the material bulk etch rate [Rojas-Herrera et al., Rev. Sci. Instrum. 86, 033501 (2015)]. Similar to the previous findings for alpha particles, protons with energies in the range 0.5–9.1 MeV are shown to produce tracks that are systematically smaller as a function of the absorbed x-ray dose in the CR-39. The reduction of track size due to x-ray dose is found to diminish with time between exposure and etching if the CR-39 is stored at ambient temperature, and complete recovery is observed after two weeks. The impact of this effect on the analysis of data from existing CR-39-based proton diagnostics on OMEGA and the National Ignition Facility is evaluated and best practices are proposed for cases in which the effect of x rays is significant

  1. Differential response of two cell lines sequentially irradiated with low X-ray doses.

    Science.gov (United States)

    Güerci, A M; Dulout, F N; Grillo, C A; Seoane, A I

    2005-05-01

    An experiment was designed to compare the effect of repeated low doses of X-rays in two different cell lines: one transformed, epithelial like and aneuploid Chinese hamster ovary K-1 (CHO-K1); the other originated from a human primary culture, fibroblast, diploid and non-transformed, MRC-5. CHO and MRC-5 cells were cultured for 14 or eight passages, respectively. Irradiation was performed once per passage when cells were in the quiescent state (90 - 95% in G1/G0). Cells were exposed to 10.0 mSv X-ray doses. Ionizing radiation did not induce apoptosis or necrosis in the exposed CHO cell population. Significant increases of low-level damaged cells (degrees 1 and 2) were found for the 14 cycles of radiation when compared with controls, except for the first irradiation cycle. No significant increases in the frequency of cells with severe damage were observed. The frequency of MRC-5 cells with low-level damage increased significantly when compared with controls for radiation cycles seven and eight. Significant increases of apoptosis, necrosis and severe damage were found only for the highest dose. Transformed and non-transformed cell types responded differently to direct and indirect damage using low-dose repeat exposures to ionizing radiation. Though more investigation is needed to understand the mechanisms of radiation effects in chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments for understanding low-dose-irradiation effects.

  2. Low Dose X-Ray Sources and High Quantum Efficiency Sensors: The Next Challenge in Dental Digital Imaging?

    Directory of Open Access Journals (Sweden)

    Arnav R. Mistry

    2014-01-01

    Full Text Available Objective(s. The major challenge encountered to decrease the milliamperes (mA level in X-ray imaging systems is the quantum noise phenomena. This investigation evaluated dose exposure and image resolution of a low dose X-ray imaging (LDXI prototype comprising a low mA X-ray source and a novel microlens-based sensor relative to current imaging technologies. Study Design. A LDXI in static (group 1 and dynamic (group 2 modes was compared to medical fluoroscopy (group 3, digital intraoral radiography (group 4, and CBCT scan (group 5 using a dental phantom. Results. The Mann-Whitney test showed no statistical significance (α=0.01 in dose exposure between groups 1 and 3 and 1 and 4 and timing exposure (seconds between groups 1 and 5 and 2 and 3. Image resolution test showed group 1 > group 4 > group 2 > group 3 > group 5. Conclusions. The LDXI proved the concept for obtaining a high definition image resolution for static and dynamic radiography at lower or similar dose exposure and smaller pixel size, respectively, when compared to current imaging technologies. Lower mA at the X-ray source and high QE at the detector level principles with microlens could be applied to current imaging technologies to considerably reduce dose exposure without compromising image resolution in the near future.

  3. Diffracted X-ray tracking for monitoring intramolecular motion in individual protein molecules using broad band X-ray

    Energy Technology Data Exchange (ETDEWEB)

    Ichiyanagi, Kouhei; Sasaki, Yuji C. [Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 609 Kiban Building 5-1-5 Kashiwanoha, Kahiwashi, Chiba 277-8561 (Japan); Japan Science and Technology Agency, CREST, CREST, Sasaki-Team, 609 Kiban Building, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Sekiguchi, Hiroshi; Hoshino, Masato; Kajiwara, Kentaro; Senba, Yasunori; Ohashi, Haruhiko; Ohta, Noboru [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Hoshisashi, Kentaro; Jae-won, Chang; Tokue, Maki; Matsushita, Yufuku [Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 609 Kiban Building 5-1-5 Kashiwanoha, Kahiwashi, Chiba 277-8561 (Japan); Nishijima, Masaki; Inoue, Yoshihisa [Department of Applied Chemistry and Office for University-Industry Collaboration, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Yagi, Naoto [Japan Science and Technology Agency, CREST, CREST, Sasaki-Team, 609 Kiban Building, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2013-10-15

    Diffracted X-ray tracking (DXT) enables the tilting and twisting motions of single protein molecules to be monitored with micro- to milliradian resolution using a highly brilliant X-ray source with a wide energy bandwidth. We have developed a technique to monitor single molecules using gold nanocrystals attached to individual protein molecules using the BL28B2 beamline at SPring-8. In this paper we present the installation of a single toroidal X-ray mirror at BL28B2 to focus X-rays in an energy range of 10–20 keV (△E/E = 82% for an X-ray with a wide energy bandwidth). With this beamline we tracked diffraction spots from gold nanocrystals over a wide angle range than that using quasi-monochromatic X-rays. Application of the wide angle DXT technique to biological systems enabled us to observe the on-site motions of single protein molecules that have been functionalized in vivo. We further extend the capability of DXT by observing the fractional tilting and twisting motions of inner proteins under various conditions. As a proof of this methodology and to determine instrumental performance the intramolecular motions of a human serum albumin complex with 2-anthracenecarboxylic acid was investigated using the BL28B2 beamline. The random tilting and twisting intramolecular motions are shown to be directly linked to the movement of individual protein molecules in the buffer solution.

  4. SU-F-J-147: Magnetic Field Dose Response Considerations for a Linac Monitor Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, M; Fallone, B [Cross Cancer Institute, Edmonton, AB (Canada)

    2016-06-15

    Purpose: The impact of magnetic fields on the readings of a linac monitor chamber have not yet been investigated. Herein we examine the total dose response as well as any deviations in the beam parameters of flatness and symmetry when a Varian monitor chamber is irradiated within an applied magnetic field. This work has direct application to the development of Linac-MR systems worldwide. Methods: A Varian monitor chamber was modeled in the Monte Carlo code PENELOPE and irradiated in the presence of a magnetic field with a phase space generated from a model of a Linac-MR prototype system. The magnetic field strength was stepped from 0 to 3.0T in both parallel and perpendicular directions with respect to the normal surface of the phase space. Dose to each of the four regions in the monitor chamber were scored separately for every magnetic field adaptation to evaluate the effect of the magnetic field on flatness and symmetry. Results: When the magnetic field is perpendicular to the phase space normal we see a change in dose response with a maximal deviation (10–25% depending on the chamber region) near 0.75T. In the direction of electron deflection we expectedly see opposite responses in chamber regions leading to a measured asymmetry. With a magnetic field parallel to the phase space normal we see no measured asymmetries, however there is a monotonic rise in dose response leveling off at about +12% near 2.5T. Conclusion: Attention must be given to correct for the strength and direction of the magnetic field at the location of the linac monitor chamber in hybrid Linac-MR devices. Elsewise the dose sampled by these chambers may not represent the actual dose expected at isocentre; additionally there may be a need to correct for the symmetry of the beam recorded by the monitor chamber. Fallone is a co-founder and CEO of MagnetTx Oncology Solutions (under discussions to license Alberta bi-planar linac MR for commercialization).

  5. 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

  6. A dose-effect curve of premature condensation chromosome ring in lymphocytes of human peripheral blood exposed to high dose of 60Co γ-rays in vitro

    International Nuclear Information System (INIS)

    Yao Bo; Li Yufang; Liu Guangxian; Huang Shan; Jiang Benrong; Ai Huisheng

    2009-01-01

    Objective: To establish a dose-effect curve of premature condensation chromosome ring (PCC-R) in lymphocytes of human peripheral blood after exposed to high doses of γ-rays. Methods: Peripheral blood samples was drawn from three healthy individuals, and exposed to 60 Co γ-rays with doses between 0 and 30 Gy. The frequencies of PCC-R in premature condensation chromosome (PCC) cells obtained by Okadaic acid (OA) induction were calculated, and a dose-effect curve was fitted. Results: PCC index tapered with dose. Frequencies of PCC-R per cell increased until 20 Gy, and then saturation was observed. The results were fitted to a lineal model up to 20 Gy: y=-0.020 + 0.052D, where y was the frequencies of PCC-R per cell, D was the radiation dose(Gy). Conclusions: The highest dose could be estimated is 20 Gy by the dose-effect curve established with PCC-R method. Its utility and validity will be verified in the future application of radiation accident. (authors)

  7. Trends in Radiation Doses to Patients from Medical X-ray Examinations in Romania

    Energy Technology Data Exchange (ETDEWEB)

    Olga Iacob; Irina Anca Popescu [Institute of Public Health, Iassy (Romania); Mihai Radu Iacob [University ' Al. I. Cuza' Iassy (Romania)

    2006-07-01

    Even if the doses received by patients during 2005 survey are lower than those estimated in the 2000 national survey on diagnostic medical radiation exposure by 27 percent, on average, their values still indicate an urgent need to develop radiation protection and optimization activities for X ray examinations, especially in pediatrics radiology. The increasing attention given in last years to radiation protection for conventional examinations, with development of national patient dosimetry protocols and reference doses, new radiation protection legislation and norms have played a significant part in this substantial reduction in effective doses. (N.C.)

  8. Evaluation of skin entrance radiation dose in pediatric patients undergoing chest X-rays exams

    International Nuclear Information System (INIS)

    Gabardo, Farly Piantini

    2016-01-01

    The aim of this work was to estimate the incident air kerma of lateral (LAT) and anterior-posterior (AP) together with posterior-anterior (PA) projection chest X-ray exams in one of the largest pediatric hospitals in Brazil. Dosimetric results are accompanied with the detailed analysis of patient characteristics and radiographer strategy. The exams of 225 (119 male and 106 female) patients were studied and 389 X-ray exams (200 AP/PA projections and 189 LAT projections) of pediatric patients were acquired. Patient thickness can be restored from age, height or weight with the uncertainty of ∼20-30%. Very slight correlation between the patient dose and thickness was observed with the difference in dose for patients of the same thickness reaching 4 times. By standardization of radiological protocols, it should be possible to keep dose within the intervals 50-100 μGy for LAT projection and 40-80 μGy for AP/PA projection. The dose values are lower than those recommended by major European guidelines to good practice. (author)

  9. An approach to routine individual internal dose monitoring at the object 'Shelter' personnel considering uncertainties

    International Nuclear Information System (INIS)

    Mel'nichuk, D.V.; Bondarenko, O.O.; Medvedjev, S.Yu.

    2002-01-01

    An approach to organisation of routine individual internal dose monitoring of the personnel of the Object 'Shelter' is presented in the work, that considers individualised uncertainties. In this aspect two methods of effective dose assessment based on bioassay are considered in the work: (1) traditional indirect method at which application results of workplace monitoring are not taken into account, and (2) a combined method in which both results of bioassay measurements and workplace monitoring are considered

  10. SU-D-209-02: Percent Depth Dose Curves for Fluoroscopic X-Ray Beam Qualities Incorporating Copper Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Wunderle, K [Cleveland Clinic Foundation, Cleveland, OH (United States); Wayne State University School of Medicine, Detroit, MI (United States); Godley, A; Shen, Z; Dong, F [Cleveland Clinic Foundation, Cleveland, OH (United States); Rakowski, J [Wayne State University School of Medicine, Detroit, MI (United States)

    2016-06-15

    Purpose: The purpose of this investigation was to quantify percent depth dose (PDD) curves for fluoroscopic x-ray beam qualities incorporating added copper filtration. Methods: A PTW (Freiburg, Germany) MP3 water tank was used with a Standard Imaging (Middleton, WI) Exradin Model 11 Spokas Chamber to measure PDD curves for 60, 80, 100 and 120 kVp x-ray beams with copper filtration ranging from 0.0–0.9 mm at 22cm and 42cm fields of view from 0 to 150 mm of water. A free-in-air monitor chamber was used to normalize the water tank data to fluctuations in output from the fluoroscope. The measurements were acquired on a Siemens (Erlangen, Germany) Artis ZeeGo fluoroscope. The fluoroscope was inverted from the typical orientation providing an x-ray beam originating from above the water tank. The water tank was positioned so that the water level was located at 60cm from the focal spot; which also represents the focal spot to interventional reference plane distance for that fluoroscope. Results: PDDs for 60, 80, 100, and 120 kVp with 0 mm of copper filtration compared well to previously published data by Fetterly et al. [Med Phys, 28, 205 (2001)] for those beam qualities given differences in fluoroscopes, geometric orientation, type of ionization chamber, and the water tank used for data collection. PDDs for 60, 80, 100, and 120 kVp with copper filtration were obtained and are presented, which have not been previously investigated and published. Conclusion: The equipment and processes used to acquire the reported data were sound and compared well with previously published data for PDDs without copper filtration. PDD data for the fluoroscopic x-ray beams incorporating copper filtration can be used as reference data for estimating organ or soft tissue dose at depth involving similar beam qualities or for comparison with mathematical models.

  11. Study of X-ray transients with Scanning Sky Monitor (SSM) onboard ...

    Indian Academy of Sciences (India)

    M. C. RAMADEVI

    MS received 1 September 2017; accepted 19 December 2017; published online 10 February 2018. Abstract. Scanning Sky Monitor (SSM) onboard AstroSat is an X-ray sky monitor in the ..... 31(2–3), 99. Ramadevi M. C., Seetha S., Babu V. C., Ashoka B. N., Sreeku- mar P. 2006, Optimization of Gas Proportional Coun-.

  12. Eye lens dosimetry for fluoroscopically guided clinical procedures: practical approaches to protection and dose monitoring

    International Nuclear Information System (INIS)

    Martin, Colin J.

    2016-01-01

    Doses to the eye lenses of clinicians undertaking fluoroscopically guided procedures can exceed the dose annual limit of 20 mSv, so optimisation of radiation protection is essential. Ceiling-suspended shields and disposable radiation absorbing pads can reduce eye dose by factors of 2-7. Lead glasses that shield against exposures from the side can lower doses by 2.5-4.5 times. Training in effective use of protective devices is an essential element in achieving good protection and acceptable eye doses. Effective methods for dose monitoring are required to identify protection issues. Dosemeters worn adjacent to the eye provide the better option for interventional clinicians, but an unprotected dosemeter worn at the neck will give an indication of eye dose that is adequate for most interventional staff. Potential requirements for protective devices and dose monitoring can be determined from risk assessments using generic values for dose linked to examination workload. (author)

  13. Impact of x-ray dose on the response of CR-39 to 1–5.5 MeV alphas

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Herrera, J., E-mail: jimmy06@mit.edu; Rinderknecht, H. G.; Zylstra, A. B.; Gatu Johnson, M.; Orozco, D.; Rosenberg, M. J.; Sio, H.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-03-15

    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-K{sub α} and K{sub β} x-rays. The CR-39 detectors were then exposed to 1–5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula.

  14. Wide field monitoring of the X-ray sky using Rotation Modulation Collimators

    DEFF Research Database (Denmark)

    Lund, Niels; Brandt, Søren

    1995-01-01

    Wide field monitoring is of particular interest in X-ray astronomy due to the strong time-variability of most X-ray sources. Not only does the time-profiles of the persistent sources contain characteristic signatures of the underlying physical systems, but, additionally, some of the most intrigui...

  15. Preliminary background prediction for the INTEGRAL x-ray monitor

    DEFF Research Database (Denmark)

    Feroci, M.; Costa, E.; Budtz-Joergensen, C.

    1996-01-01

    The JEM-X (joint European x-ray monitor) experiment will be flown onboard the ESA's INTEGRAL satellite. The instrumental background level of the two JEM-X twin detectors will depend on several parameters, among which the satellite orbit and mass distribution, and the detectors materials play...

  16. Effects of X-rays spectrum on the dose; Efectos del espectro de rayos X sobre la dosis

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez I, J. L.; Hernandez A, P. L.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Rivera M, T., E-mail: johann_greenday@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

    2015-10-15

    The X-ray equipment for diagnosis comes in different sizes and shapes depending on the scan type to perform. The X-ray spectrum is the energy distribution of the beam photons and consists of a continuous spectrum of photons braking and discrete spectrum due to the characteristic photons. The knowledge of the X-rays spectrum is important to understand like they affect the voltage changes (k Vp), current (m A), time (s) and the type of filter in the interaction mechanisms between X-rays and patient's body, the image receptor or other material that gets in the beam. Across the spectrum can be estimated the absorbed dose in any point of the patient, the quality of the image and the scattered radiation (which is related to the dose received by the equipment operator). The Monte Carlo method was used by MCNP5 code to calculate the spectrum of X-rays that occurs when a monoenergetic electron beam of 250 keV interact with targets of Mo, Rh and W. The spectra were calculated with and without filter, and the values of ambient dose equivalent were estimated, as well as the air kerma. (Author)

  17. A study of changes in the primary dose penetrating the protective apron on SID in x-ray radiography

    International Nuclear Information System (INIS)

    Choi, Seong Kwan

    2016-01-01

    This study is to figure out the amount of primary X-ray generated in SID 50cm, 1m, and 2m penetrating protective aprons in X-ray radiography for hands, skull, and lumbar spine. Results are as follows: Firstly, the exposure dose of primary X-ray which is low such as that of hand X-ray may be reduced by 270 times if protective aprons are worn, but it still slightly penetrates 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Secondly, the exposure dose of primary X-ray which is moderate such as that of skull X-ray may be reduced by 22 times if protective aprons are worn, but it still fairly penetrates 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Thirdly, the exposure dose of primary X-ray which is very high such as that of lumbar spine X-ray may be reduced b y 13 times if protective aprons a re worn, but it still penetrates a lot 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Therefore, people in X-ray room should not only wear protective aprons at any spaces that the primary X-ray can reach, but also need to stand behind the thick Pb shield to protect the body if it is inevitable to stay in the room

  18. A study of changes in the primary dose penetrating the protective apron on SID in x-ray radiography

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seong Kwan [Dept. of Radiological Technology, Kwangju Health University, Gwangju (Korea, Republic of)

    2016-12-15

    This study is to figure out the amount of primary X-ray generated in SID 50cm, 1m, and 2m penetrating protective aprons in X-ray radiography for hands, skull, and lumbar spine. Results are as follows: Firstly, the exposure dose of primary X-ray which is low such as that of hand X-ray may be reduced by 270 times if protective aprons are worn, but it still slightly penetrates 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Secondly, the exposure dose of primary X-ray which is moderate such as that of skull X-ray may be reduced by 22 times if protective aprons are worn, but it still fairly penetrates 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Thirdly, the exposure dose of primary X-ray which is very high such as that of lumbar spine X-ray may be reduced b y 13 times if protective aprons a re worn, but it still penetrates a lot 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Therefore, people in X-ray room should not only wear protective aprons at any spaces that the primary X-ray can reach, but also need to stand behind the thick Pb shield to protect the body if it is inevitable to stay in the room.

  19. Spatial variation of natural terrestrial gamma-ray dose rates in Brunei

    International Nuclear Information System (INIS)

    Hu, S.J.; Lai, K.K.; Manato, S.; Kodaira, K.

    1998-01-01

    A carbon survey of natural terrestrial gamma-rat dose rates along the main roads of the western part of Brunei Darussalam was carried out using two portable type 1.5 φ x 4 NaI(TI) and 1 φ x 2 NaI(TI) scintillation counters. A series of semicontinuous count rates measurements were performed inside a moving vehicle. This yielded equal-distance data which were analysed statistically to obtain the spatial variation of the natural terrestrial gamma-ray dose rates. The equal-distance data of dose rates were obtained by correcting for shielding effect of the car. The thickness of the pavement and the contribution from the pavement material were estimated from a correlation curve between the dose rates measured on pavements and on the nearby soils. A spectral analysis of the equal-distance data enabled us to clarify the structure of the spatial variation in dose rates. The data could be reasonably smoothened by removing the random noise components in a higher wave number region. (author). 6 refs., 7 figs., 1 tab

  20. Estimation of effective dose from limited cone beam X-ray CT examination

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, Kazuo; Arai, Yoshinori; Hashimoto, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Nishizawa, Kanae

    2000-12-01

    The limited cone beam X-ray CT (Ortho-CT) was developed on the basis of multi-functional panoramic apparatus, SCANORA (Soredex Co. Helsinki Finland). The imaging intensifier (I.I.) was built in this apparatus as a X-ray detection device instead of X-ray film. The signal provided from I.I. was converted from analog into digital by an analog-digital converter and image reconstitution was done as a three-directional image of the dimensions 3.8 cm of width, 3.0 cm height and 3.8 cm depth with the personal computer. The 3DX Multi image micro CT'' (3DX) was developed along similar lines by MORITA Co., Ltd. (Kyoto, JAPAN). In this study, the stochastic effect on organ and tissue caused by examinations using Ortho-CT and 3DX was measured. The effective dose was estimated according to the recommendation of ICRP60 and was compared with those of panoramic radiography and computed tomography. The irradiation conditions were as follows: 85 kV, 10 mA with the filtration of 3 mmAl and added 1 mmCu for Ortho-CT, and 80 kV, 2 mA and the filtration of 3.1 mmAL for 3DX. The measurement of organ and tissue dose was performed using an anthropomorphic Rando woman phantom (Alderson Research Laboratories Co., Stanfora, CN), as well as by using two different type of thermoluminescent dosimeter (TLD); Panasonic UD-170A (BeO) and UD-110S (CaSO{sub 4}: Tm). The UD-170A was for dose measurement of the inner useful X-ray beams, while the UD-110S was for outer beams. The measured organ and tissue were those recommended with ICRP60 (gonad, breast, bone marrow, lung, thyroid gland, esophagus, stomach, colon, liver, bladder, skin, brain, thymus, adrenal, kidney, spleen, pancrease, upper large intestine, uterus, eyes and major salivary gland). The imaging by Orhto-CT was made in the left maxillary 1st molar, left mandibular 1st molar and temporomandibular joint. 3DX measurement was made in the maxillary incisor region and middle ear regions other than the regions mentioned above. The skin

  1. 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

  2. Estimation of the collective effective dose to the population from medical X-ray examinations in Finland

    International Nuclear Information System (INIS)

    Tenkanen-Rautakoskia, Petra; Jaervinen, Hannu; Bly, Ritva

    2008-01-01

    The collective effective dose to the population from all X-ray examinations in Finland in 2005 was estimated. The numbers of X-ray examinations were collected by a questionnaire to the health care units (response rate 100 %). The effective doses in plain radiography were calculated using a Monte Carlo based program (PCXMC), as average values for selected health care units. For computed tomography (CT), weighted dose length product (DLP w ) in a standard phantom was measured for routine CT protocols of four body regions, for 80 % of CT scanners including all types. The effective doses were calculated from DPL w values using published conversion factors. For contrast-enhanced radiology and interventional radiology, the effective dose was estimated mainly by using published DAP values and conversion factors for given body regions. About 733 examinations per 1000 inhabitants (excluding dental) were made in 2005, slightly less than in 2000. The proportions of plain radiography, computed tomography, contrast-enhanced radiography and interventional procedures were about 92, 7, 1 and 1 %, respectively. From 2000, the frequencies (number of examinations per 1000 inhabitants) of plain radiography and contrast-enhanced radiography have decreased about 8 and 33 %, respectively, while the frequencies of CT and interventional radiology have increased about 28 and 38 %, respectively. The population dose from all X-ray examinations is about 0.43 mSv per person (in 1997 0.5 mSv). About half of this is caused by CT (in 1997 only 20 %) although the relative number of CT examinations is only 7 %. The contribution by plain radiography is 19 %, interventional radiology 17 %, and contrast-enhanced radiology 14 %. It is concluded that CT examinations are the major source of the population dose, while interventional radiology gives about the same population dose as plain radiography. For plain radiography, body examinations cause the highest effective dose. (author)

  3. Historical Building Stability Monitoring by Means of a Cosmic Ray Tracking System

    Energy Technology Data Exchange (ETDEWEB)

    Zenoni, Aldo [Department of Mechanical and Industrial Engineering of the University of Brescia, Via Branze 38, 25123 Brescia (Italy); INFN Sezione di Pavia, Via Bassi 6, 27100 Pavia (Italy)

    2015-07-01

    Cosmic ray radiation is mostly composed, at sea level, by high energy muons, which are highly penetrating particles capable of crossing kilometers of rock. The ubiquitous and steady presence at the Earth's surface and the high penetration capability have motivated the use of cosmic ray radiation also in fields beyond particle physics, from geology, archaeology, speleology to industrial applications and homeland security. In particular, in recent years, the novel technique of muon tomography has been proposed, with the aim of performing non invasive inspection of large non accessible volumes, material atomic number Z and density discrimination, and three dimension image reconstruction of the inspected volume. In the present paper, after a short recall of the physical principles and mathematical formalism on which muon tomography is based, a number of examples of application of the novel technique in industry and homeland security issues is given. Moreover, a new application of cosmic rays detection techniques in the field of civil engineering is proposed. The aim is the monitoring of the stability of large structures, in particular the static monitoring of historical buildings, where conservation constraints are more severe and the time evolution of the deformation phenomena under study may be of the order of months or years. The new technique may be seen, in some way, as the reverse problem of muon tomography. As a significant case study, the monitoring of the wooden vaulted roof of the Palazzo della Loggia in the town of Brescia, in Italy, has been considered. The feasibility as well as the performances and limitations of a monitoring system based on cosmic ray tracking have been studied by Monte Carlo simulation and discussed in comparison with more traditional monitoring systems. (authors)

  4. Historical Building Stability Monitoring by Means of a Cosmic Ray Tracking System

    International Nuclear Information System (INIS)

    Zenoni, Aldo

    2015-01-01

    Cosmic ray radiation is mostly composed, at sea level, by high energy muons, which are highly penetrating particles capable of crossing kilometers of rock. The ubiquitous and steady presence at the Earth's surface and the high penetration capability have motivated the use of cosmic ray radiation also in fields beyond particle physics, from geology, archaeology, speleology to industrial applications and homeland security. In particular, in recent years, the novel technique of muon tomography has been proposed, with the aim of performing non invasive inspection of large non accessible volumes, material atomic number Z and density discrimination, and three dimension image reconstruction of the inspected volume. In the present paper, after a short recall of the physical principles and mathematical formalism on which muon tomography is based, a number of examples of application of the novel technique in industry and homeland security issues is given. Moreover, a new application of cosmic rays detection techniques in the field of civil engineering is proposed. The aim is the monitoring of the stability of large structures, in particular the static monitoring of historical buildings, where conservation constraints are more severe and the time evolution of the deformation phenomena under study may be of the order of months or years. The new technique may be seen, in some way, as the reverse problem of muon tomography. As a significant case study, the monitoring of the wooden vaulted roof of the Palazzo della Loggia in the town of Brescia, in Italy, has been considered. The feasibility as well as the performances and limitations of a monitoring system based on cosmic ray tracking have been studied by Monte Carlo simulation and discussed in comparison with more traditional monitoring systems. (authors)

  5. 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.)

  6. Radiation dose response of N channel MOSFET submitted to filtered X-ray photon beam

    Science.gov (United States)

    Gonçalves Filho, Luiz C.; Monte, David S.; Barros, Fabio R.; Santos, Luiz A. P.

    2018-01-01

    MOSFET can operate as a radiation detector mainly in high-energy photon beams, which are normally used in cancer treatments. In general, such an electronic device can work as a dosimeter from threshold voltage shift measurements. The purpose of this article is to show a new way for measuring the dose-response of MOSFETs when they are under X-ray beams generated from 100kV potential range, which is normally used in diagnostic radiology. Basically, the method consists of measuring the MOSFET drain current as a function of the radiation dose. For this the type of device, it has to be biased with a high value resistor aiming to see a substantial change in the drain current after it has been irradiated with an amount of radiation dose. Two types of N channel device were used in the experiment: a signal transistor and a power transistor. The delivered dose to the device was varied and the electrical curves were plotted. Also, a sensitivity analysis of the power MOSFET response was made, by varying the tube potential of about 20%. The results show that both types of devices have responses very similar, the shift in the electrical curve is proportional to the radiation dose. Unlike the power MOSFET, the signal transistor does not provide a linear function between the dose rate and its drain current. We also have observed that the variation in the tube potential of the X-ray equipment produces a very similar dose-response.

  7. Action of 50 R X-ray doses on the breeding function of C3H strain mice - effect of splitting the dose, action of repeated irradiations on successive generations

    International Nuclear Information System (INIS)

    Alix, D.

    1965-01-01

    X-rays exposure effect was studied on C3H strain mice, at the standpoint of the effects produced on breeding function. The method used with this purpose was the following: single doses 20 - 30 - 40 and 50 R/dose, fractional doses: 50 R/total dose, divided in 2 - 5 - 10 or 25 irradiations distributed in one month duration. The offsprings were irradiated at the same doses than the parents, consanguinity being maintained. Statistical treatment of results was carried out, that led at the following conclusions: 1) Couples receiving single exposure of 50 R or two exposures of 25 R at one month interval give comparable results. Fractional doses do not involve the slightest diminution of X-rays effect. 2) 30 R exposure brings about a decrease in fertility, with an increase in abortions. Fertility of 20 R irradiated couples remains below controls. 3) After ten times 5 R and twenty-five 2 R, the number of abortions is the largest. Ovarian function is particularly sensitive to X-rays; one may think that twenty-five 2 R give injuries conditioning non-viability of conception products, smaller doses should produce mutations and yield births of altered genotype individuals. (author) [fr

  8. Experimental validation of a kilovoltage x-ray source model for computing imaging dose

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, Yannick, E-mail: yannick.poirier@cancercare.mb.ca [CancerCare Manitoba, 675 McDermot Ave, Winnipeg, Manitoba R3E 0V9 (Canada); Kouznetsov, Alexei; Koger, Brandon [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Tambasco, Mauro, E-mail: mtambasco@mail.sdsu.edu [Department of Physics, San Diego State University, San Diego, California 92182-1233 and Department of Physics and Astronomy and Department of Oncology, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

    2014-04-15

    Purpose: To introduce and validate a kilovoltage (kV) x-ray source model and characterization method to compute absorbed dose accrued from kV x-rays. Methods: The authors propose a simplified virtual point source model and characterization method for a kV x-ray source. The source is modeled by: (1) characterizing the spatial spectral and fluence distributions of the photons at a plane at the isocenter, and (2) creating a virtual point source from which photons are generated to yield the derived spatial spectral and fluence distribution at isocenter of an imaging system. The spatial photon distribution is determined by in-air relative dose measurements along the transverse (x) and radial (y) directions. The spectrum is characterized using transverse axis half-value layer measurements and the nominal peak potential (kVp). This source modeling approach is used to characterize a Varian{sup ®} on-board-imager (OBI{sup ®}) for four default cone-beam CT beam qualities: beams using a half bowtie filter (HBT) with 110 and 125 kVp, and a full bowtie filter (FBT) with 100 and 125 kVp. The source model and characterization method was validated by comparing dose computed by the authors’ inhouse software (kVDoseCalc) to relative dose measurements in a homogeneous and a heterogeneous block phantom comprised of tissue, bone, and lung-equivalent materials. Results: The characterized beam qualities and spatial photon distributions are comparable to reported values in the literature. Agreement between computed and measured percent depth-dose curves is ⩽2% in the homogeneous block phantom and ⩽2.5% in the heterogeneous block phantom. Transverse axis profiles taken at depths of 2 and 6 cm in the homogeneous block phantom show an agreement within 4%. All transverse axis dose profiles in water, in bone, and lung-equivalent materials for beams using a HBT, have an agreement within 5%. Measured profiles of FBT beams in bone and lung-equivalent materials were higher than their

  9. Radiation dose measurements of an on-board imager X-ray unit using optically-stimulated luminescence dosimeters

    International Nuclear Information System (INIS)

    Smith, Leon; Haque, Mamoon; Hill, Robin; Morales, Johnny

    2015-01-01

    Cone beam computed tomography (CBCT) is now widely used to image radiotherapy patients prior to treatment for the purpose of accurate patient setup. However each CBCT image delivered to a patient increases the total radiation dose that they receive. The measurement of the dose delivered from the CBCT images is not readily performed in the clinic. In this study, we have used commercially available optically stimulated luminescence (OSLD) dosimeters to measure the dose delivered by the Varian OBI on a radiotherapy linear accelerator. Calibration of the OSLDs was achieved by using a therapeutic X-ray unit. The dose delivered by a head CBCT scan was found to be 3.2 ± 0.3 mGy which is similar in magnitude to the dose of a head computed tomography (CT) scan. The results of this study suggest that the radiation hazard associated with CBCT is of a similar nature to that of conventional CT scans. We have also demonstrated that the OSLDs are suitable for these low X-ray dose measurements.

  10. Effect of dose of gamma-rays and ethylmethane sulphonate on the germination and survival of induced mutations in pigeonpea

    Energy Technology Data Exchange (ETDEWEB)

    Premsekar, S [Central Inst. for Cotton Research, Coimbatore (India). Regional Station; Appadurai, R [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1981-06-01

    The LD/sub 50/ values for germination and survival of the induced mutants (M/sub 1/) of pigeonpea (Cajanus cajan (Linn.) Millsp.) were attained with 20 and 15 krad when gamma-rays were used, and 30 and 40 mM concentration when EMS was used. In the combination treatments the half-kill dose for germination and survival was reached even at the low dose combination of 5 krad gamma-ray + 20 mM EMS. Higher doses resulted in lower pollen and seed fertility. The sterility was much enhanced in the combined treatments. The number of pods, seed yield and weight of seeds could be stimulated with 10 and 15 krad doses of gamma-rays and 20 mM of EMS. In combination treatments such a stimulatory effect was noticed in seed weight only.

  11. Occupational dose estimates for a monitored retrievable storage facility

    International Nuclear Information System (INIS)

    Harty, R.; Stoetzel, G.A.

    1986-06-01

    Occupational doses were estimated for radiation workers at the monitored retrievable storage (MRS) facility. This study provides an estimate of the occupational dose based on the current MRS facility design, examines the extent that various design parameters and assumptions affect the dose estimates, and identifies the areas and activities where exposures can be reduced most effectively. Occupational doses were estimated for both the primary storage concept and the alternate storage concept. The dose estimates indicate the annual dose to all radiation workers will be below the 5 rem/yr federal dose equivalent limit. However, the estimated dose to most of the receiving and storage crew (the workers responsible for the receipt, storage, and surveillance of the spent fuel and its subsequent retrieval), to the crane maintenance technicians, and to the cold and remote maintenance technicians is above the design objective of 1 rem/yr. The highest annual dose is received by the riggers (4.7 rem) in the receiving and storage crew. An indication of the extent to which various design parameters and assumptions affect the dose estimates was obtained by changing various design-based assumptions such as work procedures, background dose rates in radiation zones, and the amount of fuel received and stored annually. The study indicated that a combination of remote operations, increased shielding, and additional personnel (for specific jobs) or changes in operating procedures will be necessary to reduce worker doses below 1.0 rem/yr. Operations that could be made at least partially remote include the removal and replacement of the tiedowns, impact limiters, and personnel barriers from the shipping casks and the removal or installation of the inner closure bolts. Reductions of the background dose rates in the receiving/shipping and the transfer/discharge areas may be accomplished with additional shielding

  12. Development of autonomous gamma dose logger for environmental monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jisha, N. V.; Krishnakumar, D. N.; Surya Prakash, G.; Kumari, Anju; Baskaran, R.; Venkatraman, B. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

    2012-03-15

    Continuous monitoring and archiving of background radiation levels in and around the nuclear installation is essential and the data would be of immense use during analysis of any untoward incidents. A portable Geiger Muller detector based autonomous gamma dose logger (AGDL) for environmental monitoring is indigenously designed and developed. The system operations are controlled by microcontroller (AT89S52) and the main features of the system are software data acquisition, real time LCD display of radiation level, data archiving at removable compact flash card. The complete system operates on 12 V battery backed up by solar panel and hence the system is totally portable and ideal for field use. The system has been calibrated with Co-60 source (8.1 MBq) at various source-detector distances. The system is field tested and performance evaluation is carried out. This paper covers the design considerations of the hardware, software architecture of the system along with details of the front-end operation of the autonomous gamma dose logger and the data file formats. The data gathered during field testing and inter comparison with GammaTRACER are also presented in the paper. AGDL has shown excellent correlation with energy fluence monitor tuned to identify {sup 41}Ar, proving its utility for real-time plume tracking and source term estimation.

  13. Variations in 6MV x-ray radiotherapy build-up dose with treatment distance

    International Nuclear Information System (INIS)

    Butson, M.J.; Illawarra Cancer Care Centre, Wollongong, NSW; Cheung, T.; Yu, P.K.N.

    2003-01-01

    Dose in the build up region for high energy x-rays produced by a medical linear accelerator is affected by the x-ray source to patient surface distance (SSD). The use of isocentric treatments whereby the tumour is positions 100cm from the source means that depending of the depth of the tumour and the size of the patient, the SSD can vary from distances of 80cm to 100cm. To achieve larger field sizes, the SSD can also be extended out to 120cm at times. Results have shown that open fields are not significantly affected by SSD changes with deviations in percentage dose being less than 4% of maximum dose for SSD's from 80cm to 120cm SSD. With the introduction of beam modifying devices such as Perspex blocking trays, the effects are significant with a deviation of up to 22% measured at 6MV energy with a 6mm Perspex tray for SSD's from 80cm to 120cm. These variations are largest at the skin surface and reduce with depth. The use of a multi leaf collimator for blocking removes extra skin dose caused by the Perspex block trays with decreasing SSD. Copyright (2003) Australasian College of Physical Scientists and Engineers in Medicine

  14. Induction by X-rays of chromosome aberrations in male guinea-pigs and golden hamsters. 4. Dose-response for spermatogonia treated with fractionated doses

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, M F; Cox, B D [Medical Research Council, Harwell (UK). Radiobiological Research Unit

    1975-10-01

    The effect of dose fractionation on the induction of translocations by 400 and 600 rad X-rays in spermatogonia of guinea-pigs and hamsters was investigated cytologically. Three types of fractionation were used, dividing the dose into (a) two equal fractions 24h apart, (b) two equal fractions 8 weeks apart, and (c) eight or twelve equal fractions of 50 rad, at intervals of one week. The two species responded similarly throughout, but gave lower translocation yields than the mouse. The effects of the first and third types of fractionation were similar to those described previously in the mouse, and suggested that a first radiation dose modifies the spermatogonial population so that its sensitivity to a dose 24h later is altered, and that repeated radiation doses result in development of resistance to translocation induction. After 8-week fractionation, the results suggested that in guinea-pigs and hamsters, the spermatogonial population had not returned to normal by 8 weeks after the first dose, whereas in the mouse, normal sensitivity had returned by this time. The results, reported previously, of single doses of X-rays suggest that the spermatogonial population consists of sub-populations differing in sensitivity to cell killing and genetic effects. The effects of fractionated doses in the mouse suggest that the sensitive and resistant types represent different phases of the samecell type rather than two distinct types of cell. In the guinea-pig and hamster, this question remains open.

  15. Cytogenetics dosimetry: dose-response curve for low doses of X-ray; Dosimetria citogenetica: curva dosis-respuesta para bajas dosis de rayos-X

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Virginia E. Noval; Pineda Bolivar, William R.; Riano, Victor M. Pabon, E-mail: venovall.15@hotmail.com, E-mail: wrpineda@misena.edu.co, E-mail: vmpabonr@udistrital.edu.co [Universidad Distrital Francisco Jose de Caldas (UD), Bogota (Colombia). Grupo de Investigacion en Ciencia y Tecnologia Nuclear; Ureana, Cecilia Crane, E-mail: cecicrane@yahoo.com [Instituto Nacional de Salud (INS), Bogota (Colombia). Laboratorio de Genetica

    2013-07-01

    The purpose of this study was to conduct a preliminary study for the standardization in the future, the dose-response curve for low doses of X-rays, through the analysis of in vitro cultures of peripheral blood samples of 3 men and 3 women occupationally not exposed to artificial sources of ionizing radiation, age 18-40 years, where possible nonsmokers.

  16. Calculation of organ doses from environmental gamma rays using human phantoms and Monte Carlo methods. Pt. 1

    International Nuclear Information System (INIS)

    Saito, K.; Petoussi, N.; Zankl, M.; Veit, R.; Jacob, P.; Drexler, G.

    1990-01-01

    Organ doses from environmental γ-rays (U-238, Th-232, K-40) were calculated using Monte Carlo methods for three typical sources of a semi-infinite volume source in the air, an infinite plane source in the ground and a volume source in the ground. γ-ray fields in the natural environment were simulated rigourously without approximations or simplifications in the intermediate steps except for the disturbance of the radiation field by the human body which was neglected. Organ doses were calculated for four anthropomorphic phantoms representing a baby, a child, a female and a male adult. The dose of a fetus is given by the dose to the uterus of the adult female. Air kerma and dose conversion factors normalised to air kerma and to source intensity are given for monoenergetic sources and for the natural radionuclides. (orig./HP)

  17. Monitoring of dose rates and radiation flux density in working rooms

    International Nuclear Information System (INIS)

    Krajtor, S.N.

    1980-01-01

    The problems of determining the neutron field characteristics (dose equivalent rate and flux density) in relation to the environmental monitoring by radiation protection services. The measurement devices used for measuring dose equivalent rate and neutron flux density RUS-U8 multi-purpose scintillation radiometer and RUP-1 multi-purpose transportable radiometer as well as measurement technique are described. Recommendations are given for checking measuring devices calibration, registering measurement results [ru

  18. Genotoxic effects of high dose rate X-ray and low dose rate gamma radiation in ApcMin/+ mice.

    Science.gov (United States)

    Graupner, Anne; Eide, Dag M; Brede, Dag A; Ellender, Michele; Lindbo Hansen, Elisabeth; Oughton, Deborah H; Bouffler, Simon D; Brunborg, Gunnar; Olsen, Ann Karin

    2017-10-01

    Risk estimates for radiation-induced cancer in humans are based on epidemiological data largely drawn from the Japanese atomic bomb survivor studies, which received an acute high dose rate (HDR) ionising radiation. Limited knowledge exists about the effects of chronic low dose rate (LDR) exposure, particularly with respect to the application of the dose and dose rate effectiveness factor. As part of a study to investigate the development of colon cancer following chronic LDR vs. acute HDR radiation, this study presents the results of genotoxic effects in blood of exposed mice. CBAB6 F1 Apc +/+ (wild type) and Apc Min/+ mice were chronically exposed to estimated whole body absorbed doses of 1.7 or 3.2 Gy 60 Co-γ-rays at a LDR (2.2 mGy h -1 ) or acutely exposed to 2.6 Gy HDR X-rays (1.3 Gy min -1 ). Genotoxic endpoints assessed in blood included chromosomal damage (flow cytometry based micronuclei (MN) assay), mutation analyses (Pig-a gene mutation assay), and levels of DNA lesions (Comet assay, single-strand breaks (ssb), alkali labile sites (als), oxidized DNA bases). Ionising radiation (ca. 3 Gy) induced genotoxic effects dependent on the dose rate. Chromosomal aberrations (MN assay) increased 3- and 10-fold after chronic LDR and acute HDR, respectively. Phenotypic mutation frequencies as well as DNA lesions (ssb/als) were modulated after acute HDR but not after chronic LDR. The Apc Min/+ genotype did not influence the outcome in any of the investigated endpoints. The results herein will add to the scant data available on genotoxic effects following chronic LDR of ionising radiation. Environ. Mol. Mutagen. 58:560-569, 2017. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

  19. Research on self-powered detectors for gamma-ray monitoring

    International Nuclear Information System (INIS)

    Cho, S.W.; Lee, Y.J.

    1984-01-01

    Self-powered neutron detectors are used extensively in power reactors both for flux mapping and for power control and over-power protection, because of their small size, ruggedness and simplicity. But they have a few disadvantages such as high burn-up rate and background signal produced by the gamma-rays from the reactor itself. In order to overcome these disadvantages and to achieve a better understanding of gamma-ray effects of self-power detectors, a new type of self-powered detectors was designed and fabricated by the author,and experiments have carried out in the 10kCi sup(60)Co gamma irradiation facility in Korea Advanced Energy Research Institute. The configuration of the new type detectors is not of coaxial type but of paralled plate in order to obtain directional effects of gamma-ray incidence. Detector materials and dimensions are so chosen that the output current signal is large enough to be detected using some commercial measuring divice even at low dose rate and the contribution of the lead cable to the total signal is negligibly small. The results are 1)sensitivity is depended primarily on the materials of the insulator, 2)output signal has a good linearity to gamma dose rate, 3) response of detectors is prompt, but not perfect, 4) critical thickness for satusation of the output current is thinner than the range of photoelectron in the materials. (Author)

  20. Research on self-powered detectors for gamma-ray monitoring

    International Nuclear Information System (INIS)

    Cho, S.W.

    1983-01-01

    Self-powered neutron detectors are used extensively in power reactors both for flux mapping and for power control and over-power protection, because of their small size, ruggedness and simplicity. But they have a few disadvantages such as high burn-up rate and background signal produced by the gamma-rays from the reactor itself. In order to overcome these disadvantages and to achieve a better understanding of gamma-ray effects of self-powered detectors, a new type of self-powered detectors was designed and fabricated by the author, and experiments have been carried out in the 10kCi sup(60)Co gamma irradiation facility in Korea Advanced Energy Research Institute. The configuration of the new type detectors is not of coaxial type but of paralled plate in order to obtain directional effects of gamma-ray incidence. Detector materials and dimensions are so chosen that the output current signal is large enough to be detected using some commercial measuring divice even at low dose rate and the contribution of the lead cable to the totel signal is negligibly small. The results are 1) sensitivity is depended primarily on the materials of the insulator, 2) output signal has a good linearity to gamma dose rate, 3) response of detectors is prompt, but not perfect, 4) critical thickness for satusation of the output current is thinner than the range of photoelectron in the materials. (Author) πT

  1. Independent dose per monitor unit review of eight U.S.A. proton treatment facilities

    International Nuclear Information System (INIS)

    Moyers, M. F.; Ibbott, G. S.; Grant, R. L.; Summers, P. A.; Followill, D. S.

    2014-01-01

    Purpose: Compare the dose per monitor unit at different proton treatment facilities using three different dosimetry methods. Methods: Measurements of dose per monitor unit were performed by a single group at eight facilities using 11 test beams and up to six different clinical portal treatment sites. These measurements were compared to the facility reported dose per monitor unit values. Results: Agreement between the measured and reported doses was similar using any of the three dosimetry methods. Use of the ICRU 59 N D,w based method gave results approximately 3% higher than both the ICRU 59 N X and ICRU 78 (TRS-398) N D,w based methods. Conclusions: Any single dosimetry method could be used for multi-institution trials with similar conformity between facilities. A multi-institutional trial could support facilities using both the ICRU 59 N X based and ICRU 78 (TRS-398) N D,w based methods but use of the ICRU 59 N D,w based method should not be allowed simultaneously with the other two until the difference is resolved

  2. 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

  3. Estimation of population dose and risk to holding assistants from veterinary X-ray examination in Japan

    International Nuclear Information System (INIS)

    Hashizume, Tadashi; Suganuma, Tunenori; Shida, Takuo

    1989-01-01

    For the estimation of the population doses and risks of stochastic effects to assistants who hold animals during veterinary X-ray examination, a random survey of hospitals and clinics was carried out concerning age distribution of such assistants by groups of facilities. The average organ and tissue dose per examination was evaluated from the experimental data using mean technical factors such as X-ray tube voltage, tube current and field size based on the results of a nationwide survey. The population doses to the assistants were calculated to be about 14 nSv per person per year for the genetically significant dose, 3.5 nSv per person per year for per caput mean marrow dose, 3.3 nSv for the leukemia significant dose and 4.5 nSv for the malignant significant dose, respectively. The total risk of stochastic effects to the Japanese population from holding assistants was estimated using population data and it was estimated to be less than one person per year, but the cancer risks to a number of the assistants were estimated to be more than 4 x 10 -5 . (author)

  4. Reduction of patient dose delivered by CHR diagnostic x-ray examinations

    International Nuclear Information System (INIS)

    Evans, R.D.; Schlenker, R.A.

    1978-01-01

    Three changes in technique have been made which reduce the x-ray dose delivered by diagnostic examinations of patients of the Center for Human Radiobiology (CHR): Kodak Lanex Regular screens and Kodak Ortho G film have been substituted for DuPont Cronex Parspeed screens and DuPont Cronex 4 film for five projections in the MIT examinations; 3 mm Al added filtration is now used in place of 1 mm Al added filtration in the ANL examination; improvements in collimation for the ANL examination have been made. Use of the new screen-film combination at MIT has reduced the mean dose to the active marrow of the female RANDO phantom from 606 +- 69 mrad to 235 +- 16 mrad; it has reduced the ovary dose from 606 +- 40 mrad to 291 +- 19 mrad and has left the breast dose unchanged at 333 +- 103 mrad. The change from 1 mm Al to 3 mm Al added filtration at ANL, without changes in collimation, would reduce the mean marrow dose in the phantom from 232 +- 14 mrad to 175 +- 26 mrad, reduce the ovary dose from 243 +- 25 mrad to 162 +- 38 mrad and reduce the breast dose from 388 +- 35 mrad to 226 +- 9 mrad. The changes in collimation at ANL should reduce these doses even further but the quantitative effect has not been ascertained

  5. Cosmic ray LET spectra and doses on board Cosmos-2044 biosatellite

    International Nuclear Information System (INIS)

    Dudkin, V.E.; Kovalev, E.E.; Potapov, Yu.V.

    1992-01-01

    Results of the experiments on board Cosmos-2044 (Biosatellite 9) are presented. Various nuclear track detectors (NTD) (dielectric, AgCl-based, nuclear emulsions) were used to obtain the LET spectra inside and outside the satellite. The spectra from the different NTDs have proved to be in general agreement. The results of LET spectra calculations using two different models are also presented. The resultant LET distributions are used to calculate the absorbed and equivalent doses and the orbit-averaged quality factors (QF) of the cosmic rays (CR). Absorbed dose rates inside (∼ 20 g cm -2 shielding) and outside (1 g cm -2 ) the spacecraft, omitting electrons, were found to be 4.8 and 8.6 mrad d -1 , respectively, while the corresponding equivalent doses were 8.8 and 19.7 mrem d -1 . The effects of the flight parameters on the total fluence of, and on the dose from, the CR particles are analyzed. Integral dose distributions of the detected particles are also determined. The LET values which separate absorbed and equivalent doses into 50% intervals are estimated. The CR-39 dielectric NTD is shown to detect 20-30% of the absorbed dose and 60-70% of the equivalent dose in the Cosmos-2044 orbit. The influence of solar activity phase on the magnitude of the CR flux is discussed. (author)

  6. X-ray beam monitor made by thin-film CVD single-crystal diamond.

    Science.gov (United States)

    Marinelli, Marco; Milani, E; Prestopino, G; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M; Kachkanov, V; Tartoni, N; Benetti, M; Cannatà, D; Di Pietrantonio, F

    2012-11-01

    A novel beam position monitor, operated at zero bias voltage, based on high-quality chemical-vapor-deposition single-crystal Schottky diamond for use under intense synchrotron X-ray beams was fabricated and tested. The total thickness of the diamond thin-film beam monitor is about 60 µm. The diamond beam monitor was inserted in the B16 beamline of the Diamond Light Source synchrotron in Harwell (UK). The device was characterized under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of approximately 2 µm × 3 µm square. Time response, linearity and position sensitivity were investigated. Device response uniformity was measured by a raster scan of the diamond surface with the micro-focused beam. Transmissivity and spectral responsivity versus beam energy were also measured, showing excellent performance of the new thin-film single-crystal diamond beam monitor.

  7. Cytogenetic adaptive response of cultured fish cells to low doses of X-rays

    International Nuclear Information System (INIS)

    Kurihara, Yasuyuki; Etoh, Hisami; Rienkjkarn, M.

    1992-01-01

    The adaptive response was examining chromosomal aberrations and micronucleus in cultured fish cells, ULF-23 (mudminnow) and CAF-31 (gold fish). When cultured fish cells were first irradiated with small doses of X-rays, they became less sensitive to subsequent exposures to high doses. The effective adaptive dose was 4.8 cGy-9.5 cGy. Adaptive doses given cells in the G1 phase were more effective than when given in the S phase. The adaptive response was maximal at 5 hours and disappeared at 10 hours after the adaptive dose. The expression of the response was inhibited by treatment with 3-aminobenzamide, as reported for mammalian cells, and with arabinofuranoside cytosine, an inhibitor of DNA polymerase alpha. Caffeine, an inhibitor of post-replicational repair, had no effect on the response. (author)

  8. Cytogenetic adaptive response of cultured fish cells to low doses of X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, Yasuyuki; Etoh, Hisami (National Inst. of Radiological Sciences, Chiba (Japan)); Rienkjkarn, M.

    1992-12-01

    The adaptive response was examining chromosomal aberrations and micronucleus in cultured fish cells, ULF-23 (mudminnow) and CAF-31 (gold fish). When cultured fish cells were first irradiated with small doses of X-rays, they became less sensitive to subsequent exposures to high doses. The effective adaptive dose was 4.8 cGy-9.5 cGy. Adaptive doses given cells in the G1 phase were more effective than when given in the S phase. The adaptive response was maximal at 5 hours and disappeared at 10 hours after the adaptive dose. The expression of the response was inhibited by treatment with 3-aminobenzamide, as reported for mammalian cells, and with arabinofuranoside cytosine, an inhibitor of DNA polymerase alpha. Caffeine, an inhibitor of post-replicational repair, had no effect on the response. (author).

  9. Profiles of doses to the population living in the high background radiation areas in Kerala, India

    Energy Technology Data Exchange (ETDEWEB)

    Chougaonkar, M.P. E-mail: mpckar@hotmail.com; Eappen, K.P.; Ramachandran, T.V.; Shetty, P.G.; Mayya, Y.S.; Sadasivan, S.; Venkat Raj, V

    2004-07-01

    A sample study of the profiles of radiation exposures to the populations living in the high background radiation areas (HBRAs) of the monazite-bearing region in Kerala, India, has been conducted by monitoring 200 dwellings selected from two villages in this region. Each of these dwellings was monitored for 1 year and the study lasted for a period of 2 years. The indoor gamma ray dose measurements were carried out using thermo luminescent dosimeters (TLDs) and the inhalation doses due to radon, thoron and their progenies were monitored using solid-state nuclear track detector (SSNTD) based twin-cup dosimeters. Outdoor gamma ray dose measurements were carried out using Geiger Muller (GM) tube based survey meters. Annual effective doses were computed, using occupancy factors of 0.8 and 0.2, respectively, for indoor and outdoor, by adding the three components. Occupants of 41.6% of the houses surveyed were observed to receive the annual effective doses ranging between 0.5 and 5 mSv/a, 41.6% between 5 and 10 mSv/a, 10.2% between 10 and 15 mSv/a and 6.6% greater than 15 mSv/a. The inhalation component was generally smaller than the external gamma ray component and on an average it was found to constitute about 30% of the total dose. The paper presents the details of the methodology adopted and the analysis of the results.

  10. Rapid detection of chromosome rearrangement in medical diagnostic X-ray workers by using fluorescence in situ hybridization and study on dose estimation

    International Nuclear Information System (INIS)

    Wang Zhiquan; Sun Yuanming; Li Jin

    1998-01-01

    Objective: Biological doses were estimated for medical diagnostic X-ray workers. Methods: Chromosome rearrangements in X-ray workers were analysed by fluorescence in situ hybridization (FISH) with composite whole chromosome paintings number 4 and number 7. Results: The frequency of translocation in medical diagnostic X-ray workers was much higher than that in control group (P<0.01). The biological doses to individual X-ray workers were calculated by their translocation frequency. The translocation frequencies of both FISH and G-banding were in good agreement. Conclusion: The biological doses to X-ray workers are estimated by FISH first when their dosimetry records are not documented

  11. The hyper-radiosensitivity effect of human hepatoma SMMC-7721 cells exposed to low dose γ-rays and 12C ions

    International Nuclear Information System (INIS)

    Jin Xiaodong; Li Qiang; Li Wenjian; Wang Jufang; Guo Chuanling; Hao Jifang

    2006-01-01

    Hypersensitive response of mammalian cells in cell killing to X- and γ-rays has been reported at doses below 1 Gy. The purpose of this study was to examine the low dose sensitivity of human hepatoma SMMC-7721 cells irradiated with 6 Co γ-rays and 50 MeV/u 12 C ions. Experiments using γ-rays and charged particle irradiation were performed, particularly in the low dose range from 0 to 2 Gy. The survival effect of SMMC-7721 cells was measured by means of standard clonogenic assay in conjunction with a cell sorter. The result indicates SMMC-7721 cells showed hyper-radiosensitive response at low doses and increased radio-resistance at larger single doses for the carbon ions (LET = 45.2 keV/μm) and the γ-rays. However, the HRS/IRR effect caused by high-LET irradiation is different from that by low-LET radiation. This might possibly be due to the difference in the mode of energy deposition by particle beam and low-LET irradiation

  12. A method for describing the doses delivered by transmission x-ray computed tomography

    International Nuclear Information System (INIS)

    Shope, T.B.; Gagne, R.M.; Johnson, G.C.

    1981-01-01

    A method for describing the absorbed dose delivered by x-ray transmission computed tomography (CT) is proposed which provides a means to characterize the dose resulting from CT procedures consisting of a series of adjacent scans. The dose descriptor chosen is the average dose at several locations in the imaged volume of the central scan of the series. It is shown that this average dose, as defined, for locations in the central scan of the series can be obtained from the integral of the dose profile perpendicular to the scan plane at these same locations for a single scan. This method for estimating the average dose from a CT procedure has been evaluated as a function of the number of scans in the multiple scan procedure and location in the dosimetry phantom using single scan dose profiles obtained from five different types of CT systems. For the higher dose regions in the phantoms, the multiple scan dose descriptor derived from the single scan dose profiles overestimates the multiple scan average dose by no more than 10%, provided the procedure consists of at least eight scans

  13. Assessment of natural radioactivity and gamma-ray dose in monazite rich black Sand Beach of Penang Island, Malaysia.

    Science.gov (United States)

    Shuaibu, Hauwau Kulu; Khandaker, Mayeen Uddin; Alrefae, Tareq; Bradley, D A

    2017-06-15

    Activity concentrations of primordial radionuclides in sand samples collected from the coastal beaches surrounding Penang Island have been measured using conventional γ-ray spectrometry, while in-situ γ-ray doses have been measured through use of a portable radiation survey meter. The mean activity concentrations for 226 Ra, 232 Th and 40 K at different locations were found to be less than the world average values, while the Miami Bay values for 226 Ra and 232 Th were found to be greater, at 1023±47 and 2086±96Bqkg ̶ 1 respectively. The main contributor to radionuclide enrichment in Miami Bay is the presence of monazite-rich black sands. The measured data were compared against literature values and also recommended limits set by the relevant international bodies. With the exception of Miami Bay, considered an elevated background radiation area that would benefit from regular monitoring, Penang island beach sands typically pose no significant radiological risk to the local populace and tourists visiting the leisure beaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Application of gamma-ray spectroscopy in environmental monitoring

    International Nuclear Information System (INIS)

    Hobbs, B.B.; Kanipe, L.G.; Clayton, W.R.; Belvin, E.A.

    1976-01-01

    Gamma-ray spectroscopy is used as the primary analytical method in the Tennessee Valley Authority's environmental radiation monitoring program. Routine sample screening is done by means of least-squares analysis of spectra from NaI(Tl) detectors. Nonroutine or suspicious samples are analyzed by means of Ge(Li) spectral analysis. A laboratory quality control program provides internal and external checks on the reliability of analyses

  15. Retrospective Dose Reconstruction for Medical Diagnostic X Ray Workers in China using Stable Chromosome Aberrations

    International Nuclear Information System (INIS)

    Wang, Q.; Liu, P.; Li, J.; Wang, Q.; Tang, S.; Sun, M.; Wang, L.; Aoyama, T.; Sugahara, T.

    1998-01-01

    The chromosome rearrangements in medical diagnostic X ray workers were analysed using the G-banding technique and evaluated collectively in accumulated doses. A total of 9102 metaphase spreads from 84 medical diagnostic X ray workers and 17 controls were scored. The results showed that: (1) the frequencies of translocation, stable chromosome aberration and total aberration in X ray workers were significantly higher than those of controls (P < 0.05 γ 0.005), unstable chromosome aberrations (including dicentric and acentric aberration) tended upwards; (2) the main aberration in stable aberrations was reciprocal translocation; (3) the stable aberration predominated strikingly in total aberrations. The medical diagnostic X ray workers were divided into three groups according to calendar year of entry. The data showed that the frequencies of translocation, stable aberration and total aberration increased with earlier year of entry, especially in two groups who started working before 1970. According to the equation recommended by Straume et al, linear coefficient (α) in the linear quadratic model provided by Fernandez's experiment, their collective accumulation doses calculated were 0.53, 0.26 and 0.06 Gy for calendar year of entry before 1960, 1960-1969, and after 1970, in X ray workers, respectively. (author)

  16. Doses to patients from medical X-ray examinations in the UK. 2000 review

    CERN Document Server

    Hart, D; Wall, B F

    2002-01-01

    In 1992 NRPB established a National Collation Centre for measurements of doses to patients made by x-ray departments throughout the UK. This report is the second in a series of five-yearly reviews of the national patient dose database and analyses the information collected during the period January 1996 to December 2000. It includes the results of 28,000 entrance surface dose (ESD) measurements and 13,000 dose-area product (DAP) measurements for single radiographs, and 140,000 DAP measurements and 128,000 records of the fluoroscopy time for complete examinations, collected from 371 hospitals throughout the UK. Information on the patient dose distributions and exposure conditions for over 30 types of examination and radiograph is presented. National reference doses based on the rounded third quartile values of these dose distributions are recommended and are seen to be about 20% lower than corresponding values in the previous (1995) review. They have approximately halved since the original UK national referenc...

  17. Monitoring of individual doses and its information management system for CAEP's employees

    International Nuclear Information System (INIS)

    Wei Xiye; Lei Jiarong; Yuan Yonggang; Zhao Lin; Zhao Minzhi; Cui Gaoxian

    2007-01-01

    Employees' individual dose is very important to radiation workers, this paper introduces the monitoring of individual doses for the employees of CAEP in brief. A mass of employees' individual dose information records needed for being disposed, the data management software IDDMS for individual dose was developed. This paper describes the database structure, main modules, statistic and printing functions in this program. Based on much experience of many years in data management of individual dose, this program is developed using the object-oriented language Visual Foxpro 6.0. Meanwhile, it had been tested for several months. The results show that this software can be used directly for daily management of individual dose, and report forms of individual dose can also be printed easily for the related superior department. (authors)

  18. Real-time measurement and monitoring of absorbed dose for electron beams

    Science.gov (United States)

    Korenev, Sergey; Korenev, Ivan; Rumega, Stanislav; Grossman, Leon

    2004-09-01

    The real-time method and system for measurement and monitoring of absorbed dose for industrial and research electron accelerators is considered in the report. The system was created on the basis of beam parameters method. The main concept of this method consists in the measurement of dissipated kinetic energy of electrons in the irradiated product, determination of number of electrons and mass of irradiated product in the same cell by following calculation of absorbed dose in the cell. The manual and automation systems for dose measurements are described. The systems are acceptable for all types of electron accelerators.

  19. Real-time measurement and monitoring of absorbed dose for electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, Sergey E-mail: sergey_korenev@steris.com; Korenev, Ivan; Rumega, Stanislav; Grossman, Leon

    2004-10-01

    The real-time method and system for measurement and monitoring of absorbed dose for industrial and research electron accelerators is considered in the report. The system was created on the basis of beam parameters method. The main concept of this method consists in the measurement of dissipated kinetic energy of electrons in the irradiated product, determination of number of electrons and mass of irradiated product in the same cell by following calculation of absorbed dose in the cell. The manual and automation systems for dose measurements are described. The systems are acceptable for all types of electron accelerators.

  20. Real-time measurement and monitoring of absorbed dose for electron beams

    International Nuclear Information System (INIS)

    Korenev, Sergey; Korenev, Ivan; Rumega, Stanislav; Grossman, Leon

    2004-01-01

    The real-time method and system for measurement and monitoring of absorbed dose for industrial and research electron accelerators is considered in the report. The system was created on the basis of beam parameters method. The main concept of this method consists in the measurement of dissipated kinetic energy of electrons in the irradiated product, determination of number of electrons and mass of irradiated product in the same cell by following calculation of absorbed dose in the cell. The manual and automation systems for dose measurements are described. The systems are acceptable for all types of electron accelerators

  1. Biological monitoring to determine worker dose in a butadiene processing plant

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, W.E.; Hayes, R.B. [National Cancer Inst., Bethesda, MD (United States)

    1995-12-01

    Butadiene (BD) is a reactive gas used extensively in the rubber industry and is also found in combustion products. Although BD is genotoxic and acts as an animal carcinogen, the evidence for carcinogenicity in humans is limited. Extrapolation from animal studies on BD carcinogenicity to risk in humans has been controversial because of uncertainties regarding relative biologic exposure and related effects in humans vs. experimental animals. To reduce this uncertainty, a study was designed to characterize exposure to BD at a polymer production facility and to relate this exposure to mutational and cytogenetic effects. Biological monitoring was used to better assess the internal dose of BD received by the workers. Measurement of 1,2-dihydroxy-4-(N-acetylcysteinyl) butane (M1) in urine served as the biomarker in this study. M1 has been shown to correlate with area monitoring in previous studies. Most studies that relate exposure to a toxic chemical with its biological effects rely on exposure concentration as the dose metric; however, exposure concentration may or may not reflect the actual internal dose of the chemical.

  2. Dose Rate of Environmental Gamma Radiation in Java Island

    International Nuclear Information System (INIS)

    Gatot Suhariyono; Buchori; Dadong Iskandar

    2007-01-01

    The dose rate Monitoring of environmental gamma radiation at some locations in Java Island in the year 2005 / 2006 has been carried out. The dose rate measurement of gamma radiation is carried out by using the peripheral of Portable Gamma of Ray Spectrometer with detector of NaI(Tl), Merck Exploranium, Model GR-130- MINISPEC, while to determine its geographic position is used by the GPS (Global Positioning System), made in German corporation of GPS III Plus type. The division of measurement region was conducted by dividing Java Island become 66 parts with same distance, except in Jepara area that will built PLTN (Nuclear Energy Power), distance between measurement points is more closed. The results of dose rate measurement are in 66 locations in Java Island the range of (19.24 ± 4.05) nSv/hour until (150.78 ± 12.26) nSv/hour with mean (51.93 ± 36.53) nSv/h. The lowest dose rate was in location of Garut, while highest dose rate was in Ujung Lemah Abang, Jepara location. The data can be used for base line data of dose rate of environmental gamma radiation in Indonesia, specially in Java Island. The mean level of gamma radiation in Java monitoring area (0.46 mSv / year) was still lower than worldwide average effective dose rate of terrestrial gamma rays 0.5 mSv / year (report of UNSCEAR, 2000). (author)

  3. COMPARATIVE ASSESSMENT OF CHEMOTHERAPY EFFICIENCY MONITORING IN PULMONARY TUBERCULOSIS PATIENTS BY X-RAY EXAMINATION AND DIGITAL TOMOSYNTHESIS

    Directory of Open Access Journals (Sweden)

    M. M. Nikitin

    2016-01-01

    Full Text Available Goal of the study: to investigate the capabilities of digital tomosynthesis for monitoring of tuberculous changes in the lungs against the background of chemotherapy.Materials and methods. Results of chemotherapy efficiency monitored by X-ray in 55 respiratory tuberculosis patients were analyzed. Before treatment and in 2 months after chemotherapy start all patients had X-ray and DT with consequent analysis of the obtained data.Results. When monitoring the efficiency of drug therapy for pulmonary tuberculosis by DT some additional diagnostic data were obtained in 36,4% of cases compared to X-ray. The article describes specific features of tuberculous changes visualization of the chest with the follow-up of changes by DT; opportunities for X-ray monitoring efficiency enhancement in these patients are presented.Conclusions. DT provides more accurate evaluation of tuberculous changes in the lungs compared to X-ray, which greatly enhances understanding of the course of the disease and registration of the pulmonary disease cure. 

  4. Trends and the determination of effective doses for standard X-ray procedures

    International Nuclear Information System (INIS)

    Johnson, H.M.; Neduzak, C.; Gallet, J.; Sandeman, J.

    2001-01-01

    Trends in the entrance skin exposures (air kerma) for standard x-ray imaging procedures are reported for the Province of Manitoba, Canada. Average annual data per procedure using standard phantoms and standard ion chambers have been recorded since 1981. For example, chest air kerma (backscatter included) has decreased from 0.14 to 0.09 mGy. Confounding factors may negate the gains unless facility quality control programs are maintained. The data were obtained for a quality assurance and regulatory compliance program. Quoting such data for risk evaluation purposes lacks rigor hence a compartment model for organ apportioning, using organ absorbed doses and weighting factors, has been applied to determine effective dose per procedure. The effective doses for the standard procedures are presented, including the value of 0.027 mSv (1999) calculated for the effective dose in PA chest imaging. (author)

  5. The difference in backscatter factors of diagnostic X-rays by the difference in the scattering medium and in the objective dose

    International Nuclear Information System (INIS)

    Kato, Hideki; Sakai, Keita; Uchiyama, Mizuki; Suzuki, Kentaro

    2016-01-01

    The diagnostic reference levels (DRLs) of the general X-ray radiography are defined by the absorbed dose of air at the entrance surface with backscattered radiation from a scattering medium. Generally, the entrance surface dose of the general X-ray radiography is calculated from measured air kerma of primary X-ray multiplied by a backscatter factor (BSF). However, the BSF data employed at present used water for scattering medium, and was calculated based on the water-absorbed dose by incident primary photons and backscattered photons from the scattering medium. In the calculation of air dose at the entrance surface defined in DRLs, there are no theoretical consistencies for using BSF based on water dose, and this may be a cause of calculation error. In this paper, we verified the difference in BSF by the difference in the scattering medium and by the difference in the objective dose by means of the Monte Carlo simulation. In this calculation, the scattering medium was set as water and the soft-tissue, and the objective dose was set as air dose, water dose, soft-tissue dose, and skin dose. The difference in BSF calculated by the respective combination was at most about 1.3% and was less than 1% in most cases. In conclusion, even if the entrance surface dose defined by DRLs of general X-ray radiography is calculated using BSF, which set both the scattering medium and the object substance of the absorbed dose as water, a so big error doesn't show. (author)

  6. Monitoring and assessment of individual doses of occupationally exposed workers due to intake of radionuclides

    International Nuclear Information System (INIS)

    Alexander, O. A.

    2014-04-01

    Monitoring and estimation of individual intakes of radionuclides can be complex. Doses of intakes cannot be measured directly, however must be assessed from the monitoring data of the individual. The individual monitoring data includes whole body counting, excretion analysis (urine or faecal). In the estimation of these data requires that the assessor makes assumptions about the exposure scenario, including the pattern and mode of radionuclide intake. Also physicochemical characteristics of the material involved and the period of time between exposure and measurement. This project report seeks to provide some underlying guidance on monitoring programmes and data interpretation using case study. In this present study the committed effective dose (CED) 1.20mSv exceeded the recording level (i.e. 1mSv) however it was below the investigation level (i.e. 2mSv). The present study recommends that as an essential part in internal dosimetry, specialists be capable of recognizing conditions warranting follow-up bioassay and dose evaluation. Personnel should be familiar with the relevant internal dosimetry literature and the recommendations of national and international scientific organizations with regard to internal dose. (au)

  7. The teratogenic effects of low dose 60Co γ-rays on the early pregnant rats

    International Nuclear Information System (INIS)

    Lu Chunlin

    1991-01-01

    The pregnant Wistar rats were exposed to 0.5 Gy and 1.0 Gy 60 Co γ-rays at the 9th day after conception. The results: 60 Co γ-rays at dose of 1.0 Gy could induced many defects: excenphaly, hydrocephalus, gastroschisis, cleft palate and cleft lip, anophthalmia, microphthalmia, shorten tail and absent tail in surviving fetuses. The growth retardation was found from the parameters of fetal weight, height, head circle and development of skeleton. In the group of radiation dose 0.5 Gy, only hydrocephalus, absent tail and growth retardation of skeleton appeared. The results suggest that low-dose exposure in the early pregnant rats can induce fetal defects and growth retardation. The probable mechanism of teratogen and growth retardation was discussed. The cAMP levels of brain and liver of rat fetuses were reported

  8. Occlusion dose monitoring in amblyopia therapy: status, insights, and future directions.

    Science.gov (United States)

    Stewart, Catherine E; Moseley, Merrick J; Georgiou, Pantelis; Fielder, Alistair R

    2017-10-01

    Occlusion therapy remains the mainstay treatment of amblyopia, but its outcome is not assured or universally excellent. Many factors are known to influence treatment outcome, among which compliance is foremost. The occlusion dose monitor (ODM) removes one variable from the treatment equation, because it records the occlusion actually received by-rather than prescribed for-the child. Improvement observed can thus be quantitatively related to the patching received. This review summarizes the insights the ODM has provided to date particularly in elucidating the dose-response relationship. We are entering the era of personalized ophthalmology in which treatments will be tailored to the needs of the individual child and facilitated by the use of wearable monitors. Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  9. SU-E-J-23: Characteristics of X-Rays From ExacTrac and Patient Dose From Imaging Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Ding, G [Vanderbilt University, Nashville, TN (United States)

    2015-06-15

    Purpose: The purpose of this investigation is 1) provide the beam characteristics of x-rays produced by a Novalis TX ExacTrac system; 2) present a method to commission such beams, 3) present radiation dose to patients resulting from the imaging procedures. Methods: The Monte Carlo simulations were used to obtain the characteristics of kV beams and validated by measurements. The calculated beam HVLs, profiles and depth-dose curves were benchmarked against measurements. Twelve different image acquisition protocols were studied. The x-ray tube voltage ranges from 70 - 145 kV and milliampere-second (mAs) ranges from 8 - 80 mAs depending on the selection of Cranium, Head & Neck, Thorax or Abdomen imaging protocols. The beam output of each image acquisition protocol was determined by using an ionization chamber. The air kerma calibration factors of the ion chamber were obtained from an Accredited Dosimetry Calibration Laboratory for specified HVLs. Results: The agreements between measured and simulated results were within the uncertainties for HVLs, dose profiles and depth-dose curves. When %dd was normalized at 1 cm depth, its values at depth of 5 cm ranged from 45% to 66% of in water for kV beams range from 70 kVp to 145 kVp respectively. For head images, a typical dose to eye resulting from single projection ranged from 0.008 cGy to 0.025 cGy depending on the cranial image protocols selected. For a single pelvic image the skin dose could reach up to 0.1 cGy from an abdominal protocol. Conclusion: Although multiple pairs of x-ray images are commonly acquired during a daily patient treatment, the imaging doses to patients resulting from the sum of these projected x-rays are generally much less than 0.5 cGy. The knowledge obtained from this investigation can be used to estimate the image dose and optimize the used of the system.

  10. Professional exposure of medical workers: radiation levels, radiation risk and personal dose monitoring

    International Nuclear Information System (INIS)

    Bai Guang

    2005-01-01

    The application of radiation in the field of medicine is the most active area. Due to the rapid and strong development of intervention radiology at present near 20 years, particularly, the medical workers become a popularize group which most rapid increasing and also receiving the must high of professional exposure dose. Because, inter alias, radiation protection management nag training have not fully follow up, the aware of radioactive protection and appropriate approach have tot fully meet the development and need, the professional exposure dose received by medical workers, especially those being engaged in intervention radiology, are more higher, as well as have not yet fully receiving the complete personal dose monitoring, the medical workers become the population group which should be paid the most attention to. The writer would advice in this paper that all medical workers who being received a professional radiation exposure should pay more attention to the safety and healthy they by is strengthening radiation protection and receiving complete personal dose monitoring. (authors)

  11. Measurement of gamma ray flux within the containment building at the first unit of Kori nuclear power station

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. W.; Kim, K. D.; Yoon, C. H.; Han, J. M.; Hu, Y. H. [Korea Hydraulic and Nuclear Power Company, Taejon (Korea, Republic of)

    2004-07-01

    To evaluate gamma ray dose response of GM counter being used for monitoring of gamma ray field in nuclear power plants, gamma ray energy spectra and fluxes were obtained for three positions at the unit 1 of the Kori nuclear power station. By applying the response values of Eberline's E112B survey meter to the results, the doses represented on the survey meter were overestimated from 1.31 to 1.37 times when compared to the real doses for these three positions.

  12. Design of a tracking device for on-line dose monitoring in hadrontherapy

    Energy Technology Data Exchange (ETDEWEB)

    Battistoni, G. [INFN Sezione di Milano, Milano (Italy); Collamati, F.; De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Faccini, R. [Dipartimento di Fisica, “La Sapienza” Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Marafini, M. [INFN Sezione di Roma, Roma (Italy); Museo Storico della Fisica e Centro Studi e Ricerche “E. Fermi”, Roma (Italy); Mattei, I. [INFN Sezione di Milano, Milano (Italy); Muraro, S., E-mail: silvia.muraro@mi.infn.it [INFN Sezione di Milano, Milano (Italy); Paramatti, R. [INFN Sezione di Roma, Roma (Italy); Patera, V. [INFN Sezione di Roma, Roma (Italy); Museo Storico della Fisica e Centro Studi e Ricerche “E. Fermi”, Roma (Italy); Dipartimento di Scienze di Base e Applicate per Ingegneria, “La Sapienza” Università di Roma, Roma (Italy); Pinci, D. [INFN Sezione di Roma, Roma (Italy); Rucinski, A. [INFN Sezione di Roma, Roma (Italy); Dipartimento di Scienze di Base e Applicate per Ingegneria, “La Sapienza” Università di Roma, Roma (Italy); Russomando, A. [Dipartimento di Fisica, “La Sapienza” Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Roma (Italy); and others

    2017-02-11

    Hadrontherapy is a technique for cancer treatment that exploits ion beams (mostly protons and carbons). A critical issue is the accuracy that is achievable when monitoring the dose released by the beam to the tumor and to the surrounding tissues. We present the design of a tracking device, developed in the framework of the INSIDE project , capable of monitoring in real time the longitudinal profile of the dose delivered in the patient. This is possible by detecting the secondary particles produced by the interaction of the beam in the tissues. The position of the Bragg peak can be correlated to the charged particles emission point distribution measurement. The tracking device will be able to provide a fast response on the dose pattern by tracking the secondary charged fragments. The tracks are detected using 6 planes of scintillating fibers, providing the 3D coordinates of the track intersection with each plane. The fibers planes are followed by a plastic scintillator and by a small calorimeter built with a pixelated Lutetium Fine Silicate (LFS) crystal. A complete detector simulation, followed by the event reconstruction, has been performed to determine the achievable monitoring spatial resolution. - Highlights: • On-line range monitoring in hadrontherapy. • New approach: detection of charged secondary particles escaping the patient. • Correlation of longitudinal emission profile of secondaries with the beam range. • New detector integrated in a multi-modal system to be tested in clinical operation.

  13. Information from the National Institute of Radiation Protection about radiation doses and radiation risks at x-ray screening

    International Nuclear Information System (INIS)

    1975-05-01

    This report gives a specification of data concerning radiation doses and risks at x-ray investigations of lungs. The dose estimations are principally based on measurements performed in 1974 by the National Institute of Radiation Protection. The radiation doses at x-ray screening are of that magnitude that the risk for acute radiation injuries is non-existent. At these low doses it has not either been able to prove that the radiation gives long-range effects as changes in the genes or cancer of late appearance. At considerable higher doses, more than tens of thousands of millirads, a risk of cancer appearance at a small part of all irradiated persons has been proved, based on the assumption that the cancer risk is proportional to the radiation dose. Cancer can thus occure at low radiation doses too. Because of the mass radiography in Sweden 1974 about twenty cases of cancer may appear in the future. (M.S.)

  14. Radiation monitoring and dose distribution of medical workers in A.P. state 1999-2000

    International Nuclear Information System (INIS)

    Singh, D.R.; Reddy, K.S.; Kamble, M.K.; Roy, Madhumita

    2001-01-01

    Individual monitoring for external ionizing radiation is being conducted for all radiation workers in Andhra Pradesh State by TLD Unit located in Nuclear Fuel Complex, Hyderabad.The Unit comes under Personnel Monitoring Section of Bhabha Atomic Research Center, Mumbai. The aim of monitoring is to confirm that the radiation safety standards are strictly adhered in the institutions and also to investigate excessive exposures, if any. Personnel monitoring also provides data for epidemiological studies. In view of ICRP/AERB recommendations of 100 mSv dose limit for the five years block of 1994-98, the dose distribution among radiation workers in Andhra Pradesh State is analyzed for the period 1994-98. In continuation of above work, we have analyzed the data for the year 1999-2000 for various medical diagnostic procedures and these are presented

  15. Ultralow dose CT for pulmonary nodule detection with chest X-ray equivalent dose - a prospective intra-individual comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Messerli, Michael [University Zurich, Department of Nuclear Medicine, University Hospital Zurich, Zurich (Switzerland); Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard; Desbiolles, Lotus; Bauer, Ralf W.; Wildermuth, Simon [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University of Montreal, Department of Radiology, CHU Sainte-Justine, Montreal, Quebec (Canada); Rengier, Fabian [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Warschkow, Rene [Cantonal Hospital St. Gallen, Department of Surgery, St. Gallen (Switzerland); Alkadhi, Hatem [University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland); Leschka, Sebastian [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland)

    2017-08-15

    To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection. 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR). Two radiologists assessed the presence of lung nodules and their locations on ultralow dose CT. Sensitivity and specificity of the ultralow dose protocol was compared against the SOR, including subgroup analyses of different nodule sizes and types. A mixed effects logistic regression was used to test for independent predictors for sensitivity of pulmonary nodule detection. 425 nodules (mean diameter 3.7 ± 2.9 mm) were found on SOR. Overall sensitivity for nodule detection by ultralow dose CT was 91%. In multivariate analysis, nodule type, size and patients BMI were independent predictors for sensitivity (p < 0.001). Ultralow dose chest CT at 100 kV with spectral shaping enables a high sensitivity for the detection of pulmonary nodules at exposure levels comparable to plain film chest X-ray. (orig.)

  16. The elimination of low-dose hypersensitivity in Chinese hamster V79-379A cells by pretreatment with X rays or hydrogen peroxide

    International Nuclear Information System (INIS)

    Marples, B.; Joiner, M.C.

    1995-01-01

    To explain increased radioresistance over the X-ray dose range ∼ 0.5-1 Gy an inducible radioprotective mechanism triggered by DNA damage was proposed; hypersensitivity to doses much-lt Gy reflected the response prior to the activation of this system. To test this hypothesis, cells were pre-exposed to DNA-damaging agents in an attempt to induce the process prematurely. An increase in survival was evident at X-ray doses below 0.3 Gy after a priming treatment of X rays (0.05, 0.2, 1 Gy) given 6 h earlier. The protective effect was found to be transitory, requiring time for development and diminishing after two to three cell cycle times. Cycloheximide administered in the interval between the priming and challenge doses of X rays abolished the protection conferred by pretreatment, indicating the involvement of de novo protein synthesis. Oxidative damage by nontoxic doses of hydrogen peroxide (10 -4 M, but not 10 -6 M) also produced a protective effect against subsequent X irradiation. These experiments indicate survival in the hyper-radiosensitive region (much-lt 0.5 Gy) can be modified by pretreatment with agents known to affect DNA repair. In addition, the development of increased radioresistance after single doses of X rays was inhibited by cycloheximide treatment. These studies provide evidence to support the explanations proposed previously for the phenomena of increased radioresistance and hyper-radiosensitivity observed at very low X-ray doses. 57 refs., 6 figs., 3 tabs

  17. RI-60TK X-ray television introscope

    International Nuclear Information System (INIS)

    Zhdanov, A.V.; Shablov, S.V.; Morgunov, V.I.

    1985-01-01

    X-ray television introscope is briefly described. It is applied for remote viewing of welded joints and steel articles with up to 45 mm wall thickness, steel casting, articles of titanium and aluminium alloys. X-radiation penetrating the constrolled material is amplified by X-ray image converter and is passed to television camera tube. X-ray image is observed on the screen of picture monitor. Camera attachment is provided for document recording. The introscope possesses higher sensitivity and operates with lower dose rate of radiation as compared to earlier produced devices

  18. Measurement of X-ray for the dose area product and spectrum by the added filtration in Rando phantom

    Science.gov (United States)

    Lee, Jong-Woong; Kim, Eun-Soo; Choi, Jiwon; Kweon, Dae Cheol

    2014-02-01

    The most important point in the medical use of radiation is to minimize the patient entrance dose while maintaining the diagnostic information. Low-energy photons (long-wave X-ray) are unnecessary among diagnostic X-ray because they are mostly absorbed and increase the patient's entrance dose. The most effective method to eliminate the low-energy photon is use of a filtering plate. Using a filter appropriate for the image will maintain diagnostic value. Obtaining an effective image allows comparison of the resulting images in a logical objective way. This experiment was performed to determine the quality of image dosimeter when there is no filter, and when 2 mm Al, 0.1 mm Cu + 1 mm Al, 0.2 mm Cu + 1 mm Al filters are used. Using TORECK PD-8100 dose area products meter placed on top of an abdominal phantom, we measured the dose when the filter changes in this condition 85 kVp, 40 mAs, anode angle 13, source image distance 100 cm, 20 cm × 20 cm. We used the SRS-78 program for accurate comparison because we could not evaluate the difference in the image optically. The spectrum changed due to the emission of X-rays as the filter changed. We observed that the use of a filter eliminated the low-energy photons and revealed continuous X-ray and special X-ray. Therefore, the experiment highlighted the advantages of filters and confirmed that there are no changes in the quality of image through signal to noise ratio, peak signal to noise ratio, root mean square error comparison. We found that the use of filter did not lead to distortions in the image or drop in diagnostic value while minimizing the radiation dose. This means that it can help manage long-term patient dose. We conclude that we need to recommend the use of the filter as it reduces the area of dose.

  19. Evaluation of the occupational dose in hemodynamic procedures

    International Nuclear Information System (INIS)

    Silva, Amanda J. da; Fernandes, Ivani M.; Sordi, Gian Maria A.A.; Carneiro, Janete C. Gaburo

    2010-01-01

    The purpose of this study was to evaluate the dose received by health professionals in a hemodynamic service. It was necessary to know the profile of these professional, to carry out a survey the occupational external doses during the years 2000 to 2009 and to evaluate the distribution of the effective dose from the special procedures guided by fluoroscopy. A self-applied questionnaire was used to delineate the profile of health professionals, taking into account variables such as gender, age, individual monitoring time, number of jobs and tasks performed in the sector. In addition, it was performed an examination of the external individual monitoring doses from the records of the institution. The sample was composed of 35 professionals, 11 males and 24 females, with mean age of (43.0 +- 10.4) years. The average monitoring time of individuals analyzed within the institution was (11.3 +- 9.1) years, considering the period before the study. The minimum record dose level was 0.2 mSv and the maximum dose was 22.7 mSv. Doctors and nursing assistants were the professionals more exposed to radiation, due probably remaining closer to the examination table and X-ray tube during the interventional procedure. (author)

  20. Life shortening, tumor induction, and tissue dose for fission-neutron and gamma-ray irradiations

    International Nuclear Information System (INIS)

    Grahn, D.; Duggal, K.; Lombard, L.S.

    1985-01-01

    The primary focus of this program is to obtain information on the late effects of whole body exposure to low doses of a high linear-energy-transfer (LET) and a low-LET ionizing radiation in experimental animals to provide guidance for the prediction of radiation hazards to man. The information obtained takes the form of dose-response curves for life shortening and for the induction of numerous specific types of tumors. The animals are irradiated with fission neutrons from the Janus reactor and with 60 Co gamma rays, delivered as single, weekly, or duration-of-life exposures covering the range of doses and dose rates. 6 refs