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Sample records for absorbed dose rate

  1. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  2. 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

  3. Airborne and total gamma absorbed dose rates at Patiala - India

    International Nuclear Information System (INIS)

    Tesfaye, Tilahun; Sahota, H.S.; Singh, K.

    1999-01-01

    The external gamma absorbed dose rate due to gamma rays originating from gamma emitting aerosols in air, is compared with the total external gamma absorbed dose rate at the Physics Department of Punjabi University, Patiala. It has been found out that the contribution, to the total external gamma absorbed dose rate, of radionuclides on particulate matter suspended in air is about 20% of the overall gamma absorbed dose rate. (author)

  4. The measurement of the indoor absorbed dose rate in air in Beijing

    International Nuclear Information System (INIS)

    Guo Mingqiang; Pan Ziqiang; Yi Nanchang; Wei Zemin; Zhang Chao; Wang Huamin; Zhu Wencai

    1985-01-01

    This paper describes the indoor absorbed dose rate in air in Beijing. The average indoor absorbed dose rate in air is 8.29 μrad/h. The ratio of indoor to outdoor absorbed dose rate for 849 buildings is 1.51

  5. Absorbed dose to mice in prolonged irradiation by low-dose rate ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, Akihiro [National Inst. of Radiological Sciences, Chiba (Japan); Saitou, Mikio; Kudo, Iwao [and others

    2000-07-01

    In this paper, the dose absorbed by mice was evaluated as a preliminary study of the late effects of prolonged continuous irradiation of mice with low-dose rate ionizing radiation. Eight-week-old male and female SPF C3H/HeN mice in three irradiation rooms were exposed to irradiation at 8000, 400, and 20 mGy, respectively, using a {sup 137}Cs {gamma}-source. Nine racks were arranged in a circle approximately 2.5 m from the source in each room, and 10 cages were arranged on the 4 shelves of each rack. Dose distributions, such as in air at the source level, in the three rooms were estimated by using ionization chambers, and the absorbed dose distributions in the room and relative dose distributions in the cages in relation to the distance of the cage center were examined. The mean abdomen doses of the mice measured by TLD were compared with the absorbed doses in the cages. The absorbed dose distributions showed not only inverse-inverse-square-law behavior with distance from the source, but geometric symmetry in every room. The inherent scattering and absorption in each room are responsible for such behavior and asymmetry. Comparison of relative dose distributions revealed cage positions that are not suitable for experiments with high precision doses, but all positions can be used for prolonged continuous irradiation experiments if the position of the cages is rotated regularly. The mean abdomen doses of the mice were similar in each cage. The mean abdomen doses of the mice and the absorbed doses in a cage were almost the same in all cages. Except for errors concerning the positions of the racks and cages, the uncertainties in the exposure doses were estimated to be about {+-}12% for 8000 mGy group, 17% for 400 mGy group, and 35% for 20 mGy group. (K.H.)

  6. 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)

  7. Assessment of absorbed dose rate from terrestrial gamma radiation in Red Sea State

    International Nuclear Information System (INIS)

    Abdalrahman, H. E. K.

    2012-09-01

    This study is primarily conducted to contribute in the overall strategic objective of producing Sudan radiation map which will include natural radiation levels and the resultant absorbed dose rate in air. The part covered by this study is the Red Sea State. Soil samples were collected from locations lie between latitudes 17.03 ° and the 20.18 ° N and longitudes 36.06 ° E during September 2007. Activity concentrations of the primordial radionuclides, 226 Ra, 232 Th, and 40 K in the samples were measured using gamma-ray spectrometry equipped with Nal (Tl) detector. Absorbed dose rates in air a height of 1 from the ground level and the corresponding annual effective doses were calculated from the measured activities using Dose Rate Conversion Factors (DRCFs). On the average, the activity concentrations were 19.22±13.13 Bq kg -1 ( 232 Th), 17.91±15.44 Bq kg -1 ( 226 Ra) and (507.13±161.67) Bq kg -1 for 40 K. The obtained results were found to be within the global values reported in the UNSCEAR publication for normal background areas with the exception of the samples taken from Arbaat area. The absorbed dose rate in air as calculated using UNSCEAR conversion factor averaged 40.93 n Gy h -1 which corresponds to annual effective dose of 50.23 μSvy -1 . The major contribution to the total absorbed dose rate comes from 40 K, which amounts to 53.36%. Using Geographical Information System (GIS), predication maps for activity concentrations levels of the measured radionuclides in the Red Sea state was prepared to show their respective spatial distributions. Similarly, GIS predictive map was produced for annual effective dose.(Author)

  8. Primordial radionuclides in soil and their contributions to absorbed dose rate in air

    International Nuclear Information System (INIS)

    Moriones, C.R.; Duran, E.B.; Cruz, F.M. de la

    1989-01-01

    The predominant primordial radionuclides in soil which give rise to terrestrial radiation (external irradiation) were analyzed by gamma spectrometry. 40 K has the highest average activity mass concentration, i.e. 212 Bq kg -1 . 238 U and 232 Th concentrations are much lower and are only 14 and 16 Bq kg -1 respectively. Based on conversion factors given in the UNSCEAR Report (1988), the absorbed dose rates in air at one meter above the ground surface per unit activity mass concentration of primordial radionuclides were calculated. The average per caput absorbed dose rate in air received by Filipinos due to terrestrial radiation is 23 nGy h -1 . The relative contribution of 232 Th series to the total absorbed dose rate is highest, followed closely by 40 K. The contribution of 238 U series is only about one-half that of the 232 Th series. Based on the results obtained, the terrestrial component of the average per caput exposure dose rate due to natural radiation sources is 2.64 μR h -1 or roughly 3 μR h -1 . This leads to an annual average effective dose equivalent to 202 μSv. (Author). 5 annexes; 4 figs.; 3 tabs.; 6 refs

  9. Simple approximation for estimating centerline gamma absorbed dose rates due to a continuous Gaussian plume

    International Nuclear Information System (INIS)

    Overcamp, T.J.; Fjeld, R.A.

    1987-01-01

    A simple approximation for estimating the centerline gamma absorbed dose rates due to a continuous Gaussian plume was developed. To simplify the integration of the dose integral, this approach makes use of the Gaussian cloud concentration distribution. The solution is expressed in terms of the I1 and I2 integrals which were developed for estimating long-term dose due to a sector-averaged Gaussian plume. Estimates of tissue absorbed dose rates for the new approach and for the uniform cloud model were compared to numerical integration of the dose integral over a Gaussian plume distribution

  10. Measuring the absorbed dose in critical organs during low rate dose brachytherapy with 137 Cs using thermoluminescent dosemeters

    International Nuclear Information System (INIS)

    Torres, A.; Gonzalez, P.R.; Furetta, C.; Azorin, J.; Andres, U.; Mendez, G.

    2003-01-01

    Intracavitary Brachytherapy is one of the most used methods for the treatment of the cervical-uterine cancer. This treatment consists in the insertion of low rate dose 137 Cs sources into the patient. The most used system for the treatment dose planning is that of Manchester. This planning is based on sources, which are considered fixed during the treatment. However, the experience has shown that, during the treatment, the sources could be displaced from its initial position, changing the dose from that previously prescribed. For this reason, it is necessary to make measurements of the absorbed dose to the surrounding organs (mainly bladder and rectum). This paper presents the results of measuring the absorbed dose using home-made LiF: Mg, Cu, P + Ptfe thermoluminescent dosimeters (TLD). Measurements were carried out in-vivo during 20 minutes at the beginning and at the end of the treatments. Results showed that the absorbed dose to the critical organs vary significantly due to the movement of the patient during the treatment. (Author)

  11. Annual absorbed dose rate at the surface of 38 hot and mineral springs in Iran

    Energy Technology Data Exchange (ETDEWEB)

    Bahreyni Toosi, M.; Orougi, M.H.; Sadeghzadeh, A.; Aghamir, A.; Jomehzadeh, A.; Zare, H. [Mashhad Univ. of Medical Sciences, Medical Physics Dep., Faculty of Medicine (Iran, Islamic Republic of)

    2006-07-01

    Full text of publication follows: Measurement of background radiation is very important from different points of view especially to human health. In some cases exposure rate near hot and mineral springs are higher than those of normal areas. The high background radiation of hot and mineral springs is primarily due to the presence of very high amounts of Ra 226 and its decay products. In this research, environmental gamma radiation of hot and mineral springs in Khorasan, Mazandaran and Sareeyn town in Ardabil province have been measured. Equipment used in this work included: a survey meter (R.D.S. -110), a tripod and an aluminium frame to hold the survey meter horizontally.R.D.S. -110 is a microprocessor controlled detector. This survey meter has been designed for monitoring X and rays and radiation. Measurements were carried out at one meter above water level in the vicinity of hot and mineral springs. Dose rates were recorded for one hour. The average of all recorded dose rates over one hour period was taken as the exposure rate for each station. The results indicate that in Khorasan province the highest and lowest annual absorbed dose rates were equal to 10.80 mSv/y at Shanigarmab and 0.52 mSv/y at Nasradin source respectively. In Mazandaran province maximum and minimum exposure rates equal to 54.4 and 0.53 mSv/y were obtained at the surface of Talleshmahalleh and Ghormerz sources. Exposure rates at the vicinity of Sarein sources were not very different and ranged from 1.39 to 1.59 mSv/y. The results indicate that in Khorasan province Shahingarmab hot spring has the highest annual absorbed dose rate (10.80 mSv/y) and Nasraddin in Sarbisheh has the lowest level of radiation (0.62 mSv/y). In Mazandaran province Taleshmahalleh hot mineral spring has the highest annual absorbed dose rate (54.41 mSv/y) and Ghormerz mineral spring has the lowest radiation level (0.53 mSv/y). Also in Sareeyn (in Ardabil province) Abechashm source has the highest annual absorbed dose

  12. Calibration procedure for thermoluminescent dosemeters in water absorbed doses for Iridium-192 high dose rate sources

    International Nuclear Information System (INIS)

    Reyes Cac, Franky Eduardo

    2004-10-01

    Thermoluminescent dosimeters are used in brachytherapy services quality assurance programs, with the aim of guaranteeing the correct radiation dose supplied to cancer patients, as well as with the purpose of evaluating new clinical procedures. This work describes a methodology for thermoluminescent dosimeters calibration in terms of absorbed dose to water for 192 Ir high dose rate sources. The reference dose used is measured with an ionization chamber previously calibrated for 192 Ir energy quality, applying the methodology proposed by Toelli. This methodology aims to standardizing the procedure, in a similar form to that used for external radiotherapy. The work evolves the adaptation of the TRS-277 Code of the International Atomic Energy Agency, for small and big cavities, through the introduction for non-uniform experimental factor, for the absorbed dose in the neighborhood of small brachytherapy sources. In order to simulate a water medium around the source during the experimental work, an acrylic phantom was used. It guarantees the reproducibility of the ionization chamber and the thermoluminescent dosimeter's location in relation to the radiation source. The values obtained with the ionization chamber and the thermoluminescent dosimeters, exposed to a 192 Ir high dose rate source, were compared and correction factors for different source-detector distances were determined for the thermoluminescent dosimeters. A numeric function was generated relating the correction factors and the source-detector distance. These correction factors are in fact the thermoluminescent dosimeter calibration factors for the 192 Ir source considered. As a possible application of this calibration methodology for thermoluminescent dosimeters, a practical range of source-detector distances is proposed for quality control of 192 Ir high dose rate sources. (author)

  13. 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)

  14. Transcriptional Response in Mouse Thyroid Tissue after 211At Administration: Effects of Absorbed Dose, Initial Dose-Rate and Time after Administration.

    Directory of Open Access Journals (Sweden)

    Nils Rudqvist

    Full Text Available 211At-labeled radiopharmaceuticals are potentially useful for tumor therapy. However, a limitation has been the preferential accumulation of released 211At in the thyroid gland, which is a critical organ for such therapy. The aim of this study was to determine the effect of absorbed dose, dose-rate, and time after 211At exposure on genome-wide transcriptional expression in mouse thyroid gland.BALB/c mice were i.v. injected with 1.7, 7.5 or 100 kBq 211At. Animals injected with 1.7 kBq were killed after 1, 6, or 168 h with mean thyroid absorbed doses of 0.023, 0.32, and 1.8 Gy, respectively. Animals injected with 7.5 and 100 kBq were killed after 6 and 1 h, respectively; mean thyroid absorbed dose was 1.4 Gy. Total RNA was extracted from pooled thyroids and the Illumina RNA microarray platform was used to determine mRNA levels. Differentially expressed transcripts and enriched GO terms were determined with adjusted p-value 1.5, and p-value <0.05, respectively.In total, 1232 differentially expressed transcripts were detected after 211At administration, demonstrating a profound effect on gene regulation. The number of regulated transcripts increased with higher initial dose-rate/absorbed dose at 1 or 6 h. However, the number of regulated transcripts decreased with mean absorbed dose/time after 1.7 kBq 211At administration. Furthermore, similar regulation profiles were seen for groups administered 1.7 kBq. Interestingly, few previously proposed radiation responsive genes were detected in the present study. Regulation of immunological processes were prevalent at 1, 6, and 168 h after 1.7 kBq administration (0.023, 0.32, 1.8 Gy.

  15. Estimation of organ-absorbed radiation doses during 64-detector CT coronary angiography using different acquisition techniques and heart rates: a phantom study

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    Matsubara, Kosuke; Koshida, Kichiro; Kawashima, Hiroko (Dept. of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa Univ., Kanazawa (Japan)), email: matsuk@mhs.mp.kanazawa-u.ac.jp; Noto, Kimiya; Takata, Tadanori; Yamamoto, Tomoyuki (Dept. of Radiological Technology, Kanazawa Univ. Hospital, Kanazawa (Japan)); Shimono, Tetsunori (Dept. of Radiology, Hoshigaoka Koseinenkin Hospital, Hirakata (Japan)); Matsui, Osamu (Dept. of Radiology, Faculty of Medicine, Kanazawa Univ., Kanazawa (Japan))

    2011-07-15

    Background: Though appropriate image acquisition parameters allow an effective dose below 1 mSv for CT coronary angiography (CTCA) performed with the latest dual-source CT scanners, a single-source 64-detector CT procedure results in a significant radiation dose due to its technical limitations. Therefore, estimating the radiation doses absorbed by an organ during 64-detector CTCA is important. Purpose: To estimate the radiation doses absorbed by organs located in the chest region during 64-detector CTCA using different acquisition techniques and heart rates. Material and Methods: Absorbed doses for breast, heart, lung, red bone marrow, thymus, and skin were evaluated using an anthropomorphic phantom and radiophotoluminescence glass dosimeters (RPLDs). Electrocardiogram (ECG)-gated helical and ECG-triggered non-helical acquisitions were performed by applying a simulated heart rate of 60 beats per minute (bpm) and ECG-gated helical acquisitions using ECG modulation (ECGM) of the tube current were performed by applying simulated heart rates of 40, 60, and 90 bpm after placing RPLDs on the anatomic location of each organ. The absorbed dose for each organ was calculated by multiplying the calibrated mean dose values of RPLDs with the mass energy coefficient ratio. Results: For all acquisitions, the highest absorbed dose was observed for the heart. When the helical and non-helical acquisitions were performed by applying a simulated heart rate of 60 bpm, the absorbed doses for heart were 215.5, 202.2, and 66.8 mGy for helical, helical with ECGM, and non-helical acquisitions, respectively. When the helical acquisitions using ECGM were performed by applying simulated heart rates of 40, 60, and 90 bpm, the absorbed doses for heart were 178.6, 139.1, and 159.3 mGy, respectively. Conclusion: ECG-triggered non-helical acquisition is recommended to reduce the radiation dose. Also, controlling the patients' heart rate appropriately during ECG-gated helical acquisition with

  16. Verification of absorbed dose rates in reference beta radiation fields: measurements with an extrapolation chamber and radiochromic film

    International Nuclear Information System (INIS)

    Reynaldo, S. R.; Benavente C, J. A.; Da Silva, T. A.

    2015-10-01

    Beta Secondary Standard 2 (Bss 2) provides beta radiation fields with certified values of absorbed dose to tissue and the derived operational radiation protection quantities. As part of the quality assurance, metrology laboratories are required to verify the reliability of the Bss-2 system by performing additional verification measurements. In the CDTN Calibration Laboratory, the absorbed dose rates and their angular variation in the 90 Sr/ 90 Y and 85 Kr beta radiation fields were studied. Measurements were done with a 23392 model PTW extrapolation chamber and with Gafchromic radiochromic films on a PMMA slab phantom. In comparison to the certificate values provided by the Bss-2, absorbed dose rates measured with the extrapolation chamber differed from -1.4 to 2.9% for the 90 Sr/ 90 Y and -0.3% for the 85 Kr fields; their angular variation showed differences lower than 2% for incidence angles up to 40-degrees and it reached 11% for higher angles, when compared to ISO values. Measurements with the radiochromic film showed an asymmetry of the radiation field that is caused by a misalignment. Differences between the angular variations of absorbed dose rates determined by both dosimetry systems suggested that some correction factors for the extrapolation chamber that were not considered should be determined. (Author)

  17. Verification of absorbed dose rates in reference beta radiation fields: measurements with an extrapolation chamber and radiochromic film

    Energy Technology Data Exchange (ETDEWEB)

    Reynaldo, S. R. [Development Centre of Nuclear Technology, Posgraduate Course in Science and Technology of Radiations, Minerals and Materials / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Benavente C, J. A.; Da Silva, T. A., E-mail: sirr@cdtn.br [Development Centre of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Beta Secondary Standard 2 (Bss 2) provides beta radiation fields with certified values of absorbed dose to tissue and the derived operational radiation protection quantities. As part of the quality assurance, metrology laboratories are required to verify the reliability of the Bss-2 system by performing additional verification measurements. In the CDTN Calibration Laboratory, the absorbed dose rates and their angular variation in the {sup 90}Sr/{sup 90}Y and {sup 85}Kr beta radiation fields were studied. Measurements were done with a 23392 model PTW extrapolation chamber and with Gafchromic radiochromic films on a PMMA slab phantom. In comparison to the certificate values provided by the Bss-2, absorbed dose rates measured with the extrapolation chamber differed from -1.4 to 2.9% for the {sup 90}Sr/{sup 90}Y and -0.3% for the {sup 85}Kr fields; their angular variation showed differences lower than 2% for incidence angles up to 40-degrees and it reached 11% for higher angles, when compared to ISO values. Measurements with the radiochromic film showed an asymmetry of the radiation field that is caused by a misalignment. Differences between the angular variations of absorbed dose rates determined by both dosimetry systems suggested that some correction factors for the extrapolation chamber that were not considered should be determined. (Author)

  18. Absorbed dose from traversing spherically symmetric, Gaussian radioactive clouds

    International Nuclear Information System (INIS)

    Thompson, J.M.; Poston, J.W.

    1999-01-01

    If a large radioactive cloud is produced, sampling may require that an airplane traverse the cloud. A method to predict the absorbed dose to the aircrew from penetrating the radioactive cloud is needed. Dose rates throughout spherically symmetric Gaussian clouds of various sizes, and the absorbed doses from traversing the clouds, were calculated. Cloud size is a dominant parameter causing dose to vary by orders of magnitude for a given dose rate measured at some distance. A method to determine cloud size, based on dose rate readings at two or more distances from the cloud center, was developed. This method, however, failed to resolve the smallest cloud sizes from measurements made at 1,000 m to 2,000 m from the cloud center

  19. Absorbed dose in CT. Comparison by CT dose index

    International Nuclear Information System (INIS)

    Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

    2002-01-01

    Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

  20. Fast neutron radiation inactivation of Bacillus subtilis: Absorbed dose determination

    International Nuclear Information System (INIS)

    Song Lingli; Zheng Chun; Ai Zihui; Li Junjie; Dai Shaofeng

    2011-01-01

    In this paper, fast neutron inactivation effects of Bacillus subtilis were investigated with fission fast neutrons from CFBR-II reactor of INPC (Institute of Nuclear Physics and Chemistry) and mono-energetic neutrons from the Van de Graaff accelerator at Peking University. The method for determining the absorbed dose in the Bacillus subtilis suspension contained in test tubes is introduced. The absorbed dose, on account of its dependence on the volume and the form of confined state, was determined by combined experiments and Monte Carlo method. Using the calculation results of absorbed dose, the fast neutron inactivation effects on Bacillus subtilis were studied. The survival rates and absorbed dose curve was constructed. (authors)

  1. On the definition of absorbed dose

    International Nuclear Information System (INIS)

    Grusell, Erik

    2015-01-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before. - Highlights: • A stringent definition of absorbed dose is given. • This requires the definition of an irradiation and a suitable probability space. • A stringent definition is important for an understanding of the concept absorbed dose

  2. Comparison of absorbed dose in the cervix carcinoma therapy by brachytherapy of high dose rate using the conventional planning and Monte Carlo simulation

    International Nuclear Information System (INIS)

    Silva, Aneli Oliveira da

    2010-01-01

    This study aims to compare the doses received for patients submitted to brachytherapy High Dose Rate (HDR) brachytherapy, a method of treatment of the cervix carcinoma, performed in the planning system PLATO BPS with the doses obtained by Monte Carlo simulation using the radiation transport code MCNP 5 and one female anthropomorphic phantom based on voxel, the FAX. The implementation of HDR brachytherapy treatment for the cervix carcinoma consists of the insertion of an intrauterine probe and an intravaginal probe (ring or ovoid) and then two radiographs are obtained, anteroposterior (AP) and lateral (LAT) to confirm the position of the applicators in the patient and to allow the treatment planning and the determination of the absorbed dose at points of interest: rectum, bladder, sigmoid and point A, which corresponds anatomically to the crossings of the uterine arteries with ureters The absorbed doses obtained with the code MCNP 5, with the exception of the absorbed dose in the rectum and sigmoid for the simulation considering a point source of 192 Ir, are lower than the absorbed doses from PLATO BPS calculations because the MCNP 5 considers the chemical compositions and densities of FAX body, not considering the medium as water. When considering the Monte Carlo simulation for a source with dimensions equal to that used in the brachytherapy irradiator used in this study, the values of calculated absorbed dose to the bladder, to the rectum, to the right point A and to the left point A were respectively lower than those determined by the treatment planning system in 33.29, 5.01, 22.93 and 19.04%. These values are almost all larger than the maximum acceptable deviation between patient planned and administered doses (5 %). With regard to the rectum and bladder, which are organs that must be protected, the present results are in favor of the radiological protection of patients. The point A, that is on the isodose of 100%, used to tumor treatment, the results indicate

  3. Problems in radiation absorbed dose estimation from positron emitters

    International Nuclear Information System (INIS)

    Powell, G.F.; Harper, P.V.; Reft, C.S.; Chen, C.T.; Lathrop, K.A.

    1986-01-01

    The positron emitters commonly used in clinical imaging studies for the most part are short-lived, so that when they are distributed in the body the radiation absorbed dose is low even though most of the energy absorbed is from the positrons themselves rather than the annihilation radiation. These considerations do not apply to the administration pathway for a radiopharmaceutical where the activity may be highly concentrated for a brief period rather than distributed in the body. Thus, high local radiation absorbed doses to the vein for an intravenous administration and to the upper airways during administration by inhalation can be expected. For these geometries, beta point source functions (FPS's) have been employed to estimate the radiation absorbed dose in the present study. Physiologic measurements were done to determine other exposure parameters for intravenous administration of O-15 and Rb-82 and for administration of O-15-CO 2 by continuous breathing. Using FPS's to calculate dose rates to the vein wall from O-15 and Rb-82 injected into a vein having an internal radius of 1.5 mm yielded dose rates of 0.51 and 0.46 (rad x g/μCi x h), respectively. The dose gradient in the vein wall and surrounding tissues was also determined using FPS's. Administration of O-15-CO 2 by continuous breathing was also investigated. Using ultra-thin thermoluninescent dosimeters (TLD's) having the effective thickness of normal tracheal mucosa, experiments were performed in which 6 dosimeters were exposed to known concentrations of O-15 positrons in a hemicylindrical tracheal phantom having an internal radius of 0.96 cm and an effective length of 14 cm. The dose rate for these conditions was 3.4 (rads/h)/(μCi/cm 3 ). 15 references, 7 figures, 6 tables

  4. Absorbed dose from a beta source as shown by thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Wintle, A.G.; Aitken, M.J.

    1977-01-01

    The depth-dose curve was obtained for a 90 Sr- 90 Y beta source using a fine grain TL phosphor to measure the observed dose, aluminium absorbers being interposed between the source and the detector; the curve went through a maximum at an absorber thickness of about 40 mg cm -2 . This curve was then used to predict the average dose rate to various thicknesses of calcium fluoride which has a similar absorption characteristic to aluminium; these values were compared with experimentally determined dose rates. This work was done in connection with thermoluminescence dating of flint and calcite in archaeology and geology. (author)

  5. Estimation of Absorbed Dose in Occlusal Radiography

    International Nuclear Information System (INIS)

    Yoo, Young Ah; Choi, Karp Shick; Lee, Sang Han

    1990-01-01

    The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-210 Head and Neck Section R, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70 Kvp and 15 mA, 1/4 second (8 inch cone ) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In Mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

  6. Direct determination of the absorbed dose to water from 125I low dose-rate brachytherapy seeds using the new absorbed dose primary standard developed at ENEA-INMRI

    International Nuclear Information System (INIS)

    Toni, M.P.; Pimpinella, M.; Pinto, M.; Quini, M.; Cappadozzi, G.; Silvestri, C.; Bottauscio, O.

    2012-01-01

    Low-intensity radioactive sources emitting low-energy photons are used in the clinic for low dose-rate brachytherapy treatments of tumours. The dosimetry of these sources is based on reference air kerma rate measurements. The absorbed dose rate to water at the reference depth d 0 = 1 cm, D w , 1 cm, is then obtained by a conversion procedure with a large relative standard uncertainty of about 5%. This paper describes a primary standard developed at ENEA-INMRI to directly measure D w , 1 cm due to LDR sources. The standard is based on a large-angle and variable-volume ionization chamber, embedded in a graphite phantom and operating under 'wall-less air chamber' conditions. A set of correction and conversion factors, based on experiments and Monte Carlo simulations, are determined to obtain the value of D w , 1 cm from measurements of increment of ionization current with increasing chamber volume. The relative standard uncertainty on D w , 1 cm is 2.6%, which is appreciably lower than the current uncertainty. Characteristics of the standard, its associated uncertainty budget, and some experimental results are given for 125 I BEBIG I25.S16.C brachytherapy seeds. Finally, results of the experimental determination of the dose-rate constant 1 cm, traceable to the D w , 1 cm and the low-energy air kerma ENEA-INMRI standards, are given. The relative standard uncertainty on 1 cm is 2.9%, appreciably lower than the typical uncertainty (4.8%) of the values available in the literature. (authors)

  7. The absorbed dose to blood from blood-borne activity

    International Nuclear Information System (INIS)

    Hänscheid, H; Fernández, M; Lassmann, M

    2015-01-01

    The radiation absorbed dose to blood and organs from activity in the blood is relevant for nuclear medicine dosimetry and for research in biodosimetry. The present study provides coefficients for the average absorbed dose rates to the blood from blood-borne activity for radionuclides frequently used in targeted radiotherapy and in PET diagnostics. The results were deduced from published data for vessel radius-dependent dose rate coefficients and reasonable assumptions on the blood-volume distribution as a function of the vessel radius. Different parts of the circulatory system were analyzed separately. Vessel size information for heart chambers, aorta, vena cava, pulmonary artery, and capillaries was taken from published results of morphometric measurements. The remaining blood not contained in the mentioned vessels was assumed to reside in fractal-like vascular trees, the smallest branches of which are the arterioles or venules. The applied vessel size distribution is consistent with recommendations of the ICRP on the blood-volume distribution in the human. The resulting average absorbed dose rates to the blood per nuclear disintegration per milliliter (ml) of blood are (in 10 −11  Gy·s −1 ·Bq −1 ·ml) Y-90: 5.58, I-131: 2.49, Lu-177: 1.72, Sm-153: 2.97, Tc-99m: 0.366, C-11: 4.56, F-18: 3.61, Ga-68: 5.94, I-124: 2.55. Photon radiation contributes 1.1–1.2·10 −11  Gy·s −1 ·Bq −1 ·ml to the total dose rate for positron emitters but significantly less for the other nuclides. Blood self-absorption of the energy emitted by ß-particles in the whole blood ranges from 37% for Y-90 to 80% for Tc-99m. The correspondent values in vascular trees, which are important for the absorbed dose to organs, range from 30% for Y-90 to 82% for Tc-99m. (paper)

  8. BRIGITTE, Dose Rate and Heat Source and Energy Flux for Self-Absorbing Rods

    International Nuclear Information System (INIS)

    Jegu, M.; Clement, M.

    1978-01-01

    1 - Nature of physical problem solved: Calculation of dose rate, heat sources or energy flux. The sources are self-absorbing radioactive rods. The shielding consists of blocks of which the cross section can be defined. 2 - Method of solution: Exponential attenuation and build-up factor between source points and detector points. Source integration with error estimate. Automatic or controlled build-up with monitor print-out. 3 - Restrictions on the complexity of the problem: Number of energy points, regions, detector points, abscissa points of the rod, vertical position of the rod, are all limited to ten. The maximum total number of vertical steps is 124

  9. Absorbed dose optimization in the microplanar beam radiotherapy

    International Nuclear Information System (INIS)

    Company, F.Z.; Jaric, J.; Allen, B.J.

    1996-01-01

    Full text: Recent advances in synchrotron generated X-ray beams with high fluence rate, small divergence and sharply defined microbeam margins permit investigation of the application of an array of closely spaced, parallel or converging microbeams for radiotherapy. The proposed technique takes advantage of the repair mechanism hypothesis of capillary endothelial cells between alternate microbeam zones, which regenerates the lethally irradiated capillaries. Unlike a pencil beam, more accurate dose calculation, beam width and spacing are essential to minimise radiation damage to normal tissue cells outside the target. The absorbed dose between microbeam zones should be kept below the threshold for irreversible radiation damage. Thus the peak-to-valley ratio for the dose distribution should be optimized. The absorbed dose profile depends on the energy of the incident beam and the composition and density of the medium. Using Monte Carlo computations, the radial absorbed dose of single 24 x 24 μm 2 cross-section X-ray beams of different energies in a tissue/lung/tissue phantom was investigated. The results indicated that at 100 keV, closely spaced square cross-sectional microbeams can be applied to the lung. A bundle of parallel 24 μm-wide planar microbeams spaced at 200 μm intervals provides much more irradiation coverage of tissue than is provided by a bundle of parallel, square cross-sectional microbeam, although the former is associated with much smaller Peak (maximum absorbed dose on the beam axis) -to-Valley ( minimum interbeam absorbed dose ) ratios than the latter. In this study the lateral and depth dose of single and multiple microplanar beams with beam dimensions of width 24 μm and 48 μm and height 2-20 cm with energy of 100 keV in a tissue/lung/tissue phantom are investigated. The EGS4 Monte Carlo code is used to calculate dose profiles at different depths and bundles of beams (2 x 2 cm 2 to 20 x 20 cm 2 square cross section) with a 150 μm 200 μm and

  10. Absorbed dose by a CMOS in radiotherapy

    International Nuclear Information System (INIS)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L. C.

    2011-10-01

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  11. Absorbed dose by a CMOS in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-10-15

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  12. Using RADFET for the real-time measurement of gamma radiation dose rate

    Science.gov (United States)

    Andjelković, Marko S.; Ristić, Goran S.; Jakšić, Aleksandar B.

    2015-02-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h-1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

  13. Using RADFET for the real-time measurement of gamma radiation dose rate

    International Nuclear Information System (INIS)

    Andjelković, Marko S; Ristić, Goran S; Jakšić, Aleksandar B

    2015-01-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h −1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose. (paper)

  14. Proposal concerning the absorbed dose conversion factor

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, A [National Inst. of Radiological Sciences, Chiba (Japan)

    1978-03-01

    New definitions of the absorbed dose conversion factors Csub(lambda) and Csub(E) are proposed. The absorbed dose in water is given by the product of absorbed dose conversion factor, exposure calibration factor, ionisation chamber reading, cap displacement correction factor and perturbation correction factor. At exposure calibration the material of the build-up cap must be the same as that of the chamber wall. An ionisation chamber of which the wall material is water-equivalent or air-equivalent may be used. In the latter case the wall must be thin. For these two cases absorbed dose conversion factors are introduced and it is recommended that either of the two sets should be adopted. Furthermore, if the chamber wall is neither water- nor air-equivalent, the factor by which these currently defined values should be multiplied is also given: again the wall must be thin. The ICRU definitions of Csub(lambda) and Csub(E) are inconsistent, as recently pointed out, while the definitions presented here are consistent.

  15. The MIRD method of estimating absorbed dose

    International Nuclear Information System (INIS)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine

  16. Gamma dose rates to body organs from immersion in a semi-infinite radioactive cloud; an alternate approach using absorbed fraction data for internal radionuclides

    International Nuclear Information System (INIS)

    Gillespie, F.C.

    1982-01-01

    This note shows that reasonable estimates of absorbed γ-dose rates for specific organs arising from whole body immersion in semi-infinite radioactive clouds may be obtained very simply from well known data on absorbed fractions for mono-energetic γ-sources uniformly distributed in the whole body. (author)

  17. Natural terrestrial radiation exposure in Hong Kong. A survey on environmental gamma absorbed dose rate in air

    International Nuclear Information System (INIS)

    Wong, M.C.; Poon, H.T.; Chan, Y.K.; So, C.K.

    2000-01-01

    Hong Kong is a metropolitan city located on the southern coast of China with a population of some six million. About 90% of the population is concentrated in heavily built-up residential and commercial areas, which accounts for less than 50% of the total area in the territory. Hong Kong Observatory, 134A Nathan Road, Kowloon, Hong Kong, China. In order to understand the spatial variations in the environmental radiation levels in Hong Kong, the Hong Kong Observatory (HKO) in early 1999 conducted a study of the environmental gamma absorbed dose rate in air. The study combined data collected by the HKO radiation monitoring network (RMN) and data from a comprehensive territory-wide radiological survey conducted in January and February 1999. The RMN of ten stations each equipped with a Reuter-Stokes Model RSS-1013 HPIC has been in operation since 1987 to continuously monitor the environmental radiation levels over the territory as part of the emergency monitoring programme for response to nuclear accidents at a nearby nuclear power station. The terrestrial component of the environmental radiation field was estimated by subtracting from the measurements the cosmic contribution, which is determined to be about 39 nGy/h from measurements conducted over two large fresh water reservoirs. The RMN data with the long history was analysed to derive the seasonal variations in the environmental radiation levels. On average the environmental gamma absorbed dose rate in air in January and February is 1.03 times of the annual figure. This seasonal correction was applied to the results of the year 1999 survey. As the radiation field in the heavily built-up areas is enhanced by contribution from buildings, in the territory-wide survey measurements were made both in the open field and built-up areas. The territory of Hong Kong was divided into 42 grid boxes of 5 km x 5 km for open field and 61 grid boxes of 2.5 km x 2.5 km for built-up areas according to the population and land use. A

  18. Considerations on absorbed dose estimates based on different β-dose point kernels in internal dosimetry

    International Nuclear Information System (INIS)

    Uchida, Isao; Yamada, Yasuhiko; Yamashita, Takashi; Okigaki, Shigeyasu; Oyamada, Hiyoshimaru; Ito, Akira.

    1995-01-01

    In radiotherapy with radiopharmaceuticals, more accurate estimates of the three-dimensional (3-D) distribution of absorbed dose is important in specifying the activity to be administered to patients to deliver a prescribed absorbed dose to target volumes without exceeding the toxicity limit of normal tissues in the body. A calculation algorithm for the purpose has already been developed by the authors. An accurate 3-D distribution of absorbed dose based on the algorithm is given by convolution of the 3-D dose matrix for a unit cubic voxel containing unit cumulated activity, which is obtained by transforming a dose point kernel into a 3-D cubic dose matrix, with the 3-D cumulated activity distribution given by the same voxel size. However, beta-dose point kernels affecting accurate estimates of the 3-D absorbed dose distribution have been different among the investigators. The purpose of this study is to elucidate how different beta-dose point kernels in water influence on the estimates of the absorbed dose distribution due to the dose point kernel convolution method by the authors. Computer simulations were performed using the MIRD thyroid and lung phantoms under assumption of uniform activity distribution of 32 P. Using beta-dose point kernels derived from Monte Carlo simulations (EGS-4 or ACCEPT computer code), the differences among their point kernels gave little differences for the mean and maximum absorbed dose estimates for the MIRD phantoms used. In the estimates of mean and maximum absorbed doses calculated using different cubic voxel sizes (4x4x4 mm and 8x8x8 mm) for the MIRD thyroid phantom, the maximum absorbed doses for the 4x4x4 mm-voxel were estimated approximately 7% greater than the cases of the 8x8x8 mm-voxel. They were found in every beta-dose point kernel used in this study. On the other hand, the percentage difference of the mean absorbed doses in the both voxel sizes for each beta-dose point kernel was less than approximately 0.6%. (author)

  19. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetite, Bahia, Brazil

    International Nuclear Information System (INIS)

    Pereira, Wagner de S; Kelecom, Alphonse; Azevedo Py Junior, Delcy de

    2008-01-01

    The uranium mining at Caetite (Uranium Concentrate Unit--URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5x10 3 μGy y -1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51x10 0 μGy y -1 , that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota

  20. Concentration activities of natural radionuclides in three fish species in Brazilian coast and their contributions to the absorbed doses

    International Nuclear Information System (INIS)

    Pereira, Wagner de S.; Py Junior, Delcy de A.; Kelecom, Alphonse

    2009-01-01

    Activity concentrations of U-238, Ra-226, Pb-210, Th-232 e Ra-228 were analysed in three fish species at the Brasilian Coast. The fish 'Cubera snapper' (Lutjanus cyanopterus, Cuvier, 1828), in the region of Ceara and 'Whitemouth croaker' (Micropogonias furnieri, Desmarest, 1823) and 'Lebranche mullet' (Mugil liza, Valenciennes, 1836) in the region of Rio de Janeiro. These concentrations were transformed in absorbed dose rate using a dose conversion factor in unit of gray per year (μGy y -1 ), per becquerel per kilogram (Bq kg -1 ). Only the absorbed dose due to intake of radionuclides was examined, and the contributions due to radionuclides present in water and sediment were disregarded. The radionuclides were considered to be uniformly distributed in the fish body. The limit of the dose rate used, proposed by the Department of Energy of the USA, is equal to 3.65 10 03 mGy y -1 . The average dose rate due to the studied radionuclides is equal to 6.09 10 00 μGy y -1 , a value minor than 0.1% than the limits indicated by DOE, and quite similar to that found in the literature for 'benthic' fish. The most important radionuclides were the alpha emitters Ra-226 having 61 % of absorbed dose rate. U-238 and Th-232, each contributes with approximately 20 % of the absorbed dose rate. These three radionuclides are responsible for almost 100% of the dose rate received by the studied organisms. The beta emitters Ra-228 and Pb-210 account for approximately 1 % of the absorbed dose rate. (author)

  1. Accuracy of a dose-area product compared to an absorbed dose to water at a point in a 2 cm diameter field

    Energy Technology Data Exchange (ETDEWEB)

    Dufreneix, S.; Ostrowsky, A.; Rapp, B.; Daures, J.; Bordy, J. M., E-mail: jean-marc.bordy@cea.fr [CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), Gif-sur-Yvette F-91191 (France)

    2016-07-15

    Purpose: Graphite calorimeters with a core diameter larger than the beam can be used to establish dosimetric references in small fields. The dose-area product (DAP) measured can theoretically be linked to an absorbed dose at a point by the determination of a profile correction. This study aims at comparing the DAP-based protocol to the usual absorbed dose at a point protocol in a 2 cm diameter field for which both references exist. Methods: Two calorimeters were used, respectively, with a sensitive volume of 0.6 cm (for the absorbed dose at a point measurement) and 3 cm diameter (for the DAP measurement). Profile correction was calculated from a 2D dose mapping using three detectors: a PinPoint chamber, a synthetic diamond, and EBT3 films. A specific protocol to read EBT3 films was implemented and the dose-rate and energy dependences were studied to assure a precise measurement, especially in the penumbra and out-of-field regions. Results: EBT3 films were found independent on dose rates over the range studied but showed a strong under-response (18%) at low energies. Depending on the dosimeter used for calculating the profile correction, a deviation of 0.8% (PinPoint chamber), 0.9% (diamond), or 1.9% (EBT3 films) was observed between the calibration coefficient derived from DAP measurements and the one directly established in terms of absorbed dose to water at a point. Conclusions: The DAP method can currently be linked to the classical dosimetric reference system based in an absorbed dose at a point only with a confidence interval of 95% (k = 2). None of the detectors studied can be used to determine an absorbed dose to water at a point from a DAP measurement with an uncertainty smaller than 1.2%.

  2. Radiation-Induced Color Centers in LiF for Dosimetry at High Absorbed Dose Rates

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Ellis, S. C.

    1980-01-01

    Color centers formed by irradiation of optically clear crystals of pure LiF may be analyzed spectrophotometrically for dosimetry in the absorbed dose range from 102 to 107 Gy. Routine monitoring of intense electron beams is an important application. Both 6LiF and 7LiF forms are commercially...... available, and when used with filters as albedo dosimeters in pairs, they provide discrimination of neutron and gamma-ray doses....

  3. Absorbed Dose Rate Due to Intake of Natural Radionuclides by Tilapia Fish (Tilapia nilotica,Linnaeus, 1758) Estimated Near Uranium Mining at Caetité, Bahia, Brazil

    Science.gov (United States)

    Pereira, Wagner de S.; Kelecom, Alphonse; Py Júnior, Delcy de Azevedo

    2008-08-01

    The uranium mining at Caetité (Uranium Concentrate Unit—URA) is in its operational phase. Aiming to estimate the radiological environmental impact of the URA, a monitoring program is underway. In order to preserve the biota of the deleterious effects from radiation and to act in a pro-active way as expected from a licensing body, the present work aims to use an environmental protection methodology based on the calculation of absorbed dose rate in biota. Thus, selected target organism was the Tilapia fish (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). As, in Brazil there are no radiation exposure limits adopted for biota the value proposed by the Department of Energy (DOE) of the United States of 3.5×103 μGy y-1 has been used. The derived absorbed dose rate calculated for Tilapia was 2.51×100 μGy y-1, that is less than 0.1% of the dose limit established by DOE. The critical radionuclide was Ra-226, with 56% of the absorbed dose rate, followed by U-238 with 34% and Th-232 with 9%. This value of 0.1% of the limit allows to state that, in the operational conditions analyzed, natural radionuclides do not represent a radiological problem to biota.

  4. 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.)

  5. Specification of absorbed dose for reporting a therapeutic irradiation

    International Nuclear Information System (INIS)

    Wambersie, A.; Chassagne, D.

    1981-01-01

    The problem of dose specification in external beam therapy with photons and electrons has been dealt with in ICRU Report 29 (1978). This problem arises from the fact that the absorbed dose distribution is usually not uniform in the target volume and that for the purpose of treatment reporting a nominal absorbed dose - which will be called target absorbed dose - has to be selected. When comparing the clinical results obtained between radiotherapy centres, the differences in the reported target absorbed doses which can be introduced by differences in the methods of dose specification often are much larger than the differences related to the dosimetric procedures themselves. This shows the importance of the problem. In this paper, some definitions of terms and concepts currently used in radiotherapy are first recalled: tumour volume, target volume, treatment volume, etc. These definitions have been proposed in ICRU Report 29 for photon and electron beams; they can be extended to any kind of irradiation. For external beam therapy with photons and electrons, the target absorbed dose is defined as the absorbed dose at selected point(s) (specification point(s)) having a meaningful relation to the target volume and/or the irradiation beams. Examples are discussed for typical cases. As far as interstitial and intracavitary therapy is concerned, the problem is more complex and no recommendations have so far been made by the ICRU Commission. A major difficulty arises from the sharp dose gradient as a function of the distance to the sources. The particular case of the treatment of cervix carcinoma is considered and some possible methods of specification are discussed: (1) the indication of the sources (in adequate units) and the duration of the application, (2) the absorbed doses at selected reference points (bladder, rectum, bony structures) and (3) the description of the tissue volume (height, width, thickness) encompassed by a given isodose surface (60Gy). (author)

  6. The Australian Commonwealth standard of measurement for absorbed radiation dose

    International Nuclear Information System (INIS)

    Sherlock, S.L.

    1990-06-01

    This report documents the absorbed dose standard for photon beams in the range from 1 to 25 MeV. Measurements of absorbed dose in graphite irradiated by a beam of cobalt-60 gamma rays from an Atomic Energy of Canada Limited (AECL) E1 Dorado 6 teletherapy unit are reported. The measurements were performed using a graphite calorimeter, which is the primary standard for absorbed dose. The measurements are used to calibrate a working standard ion chamber in terms of absorbed dose in graphite. Details of the methods, results and correction factors applied are given in Appendices. 13 refs., 6 tabs., 6 figs

  7. Graves' disease radioiodine-therapy: Choosing target absorbed doses for therapy planning

    Energy Technology Data Exchange (ETDEWEB)

    Willegaignon, J., E-mail: j.willegaignon@gmail.com; Sapienza, M. T.; Coura-Filho, G. B.; Buchpiguel, C. A. [Cancer Institute of São Paulo State (ICESP), Clinical Hospital, School of Medicine, University of São Paulo, São Paulo 01246-000 (Brazil); Nuclear Medicine Service, Department of Radiology, School of Medicine, University of São Paulo, Sao Paulo 01246-000 (Brazil); Watanabe, T. [Nuclear Medicine Service, Department of Radiology, School of Medicine, University of São Paulo, São Paulo 01246-000 (Brazil); Traino, A. C. [Unit of Medical Physics, Azienda Ospedaliero-Universitaria Pisana, Pisa 56126 (Italy)

    2014-01-15

    Purpose: The precise determination of organ mass (m{sub th}) and total number of disintegrations within the thyroid gland (A{sup ~}) are essential for thyroid absorbed-dose calculations for radioiodine therapy. Nevertheless, these parameters may vary according to the method employed for their estimation, thus introducing uncertainty in the estimated thyroid absorbed dose and in any dose–response relationship derived using such estimates. In consideration of these points, thyroid absorbed doses for Graves’ disease (GD) treatment planning were calculated using different approaches to estimating the m{sub th} and the A{sup ~}. Methods: Fifty patients were included in the study. Thyroid{sup 131}I uptake measurements were performed at 2, 6, 24, 48, 96, and 220 h postadministration of a tracer activity in order to estimate the effective half-time (T{sub eff}) of {sup 131}I in the thyroid; the thyroid cumulated activity was then estimated using the T{sub eff} thus determined or, alternatively, calculated by numeric integration of the measured time-activity data. Thyroid mass was estimated by ultrasonography (USG) and scintigraphy (SCTG). Absorbed doses were calculated with the OLINDA/EXM software. The relationships between thyroid absorbed dose and therapy response were evaluated at 3 months and 1 year after therapy. Results: The average ratio (±1 standard deviation) betweenm{sub th} estimated by SCTG and USG was 1.74 (±0.64) and that between A{sup ~} obtained by T{sub eff} and the integration of measured activity in the gland was 1.71 (±0.14). These differences affect the calculated absorbed dose. Overall, therapeutic success, corresponding to induction of durable hypothyroidism or euthyroidism, was achieved in 72% of all patients at 3 months and in 90% at 1 year. A therapeutic success rate of at least 95% was found in the group of patients receiving doses of 200 Gy (p = 0.0483) and 330 Gy (p = 0.0131) when m{sub th} was measured by either USG or SCTG and A

  8. Assessment of a new p-Mosfet usable as a dose rate insensitive gamma dose sensor

    International Nuclear Information System (INIS)

    Vettese, F.; Donichak, C.; Bourgeault, P.

    1995-01-01

    Dosimetric response of unbiased MOS devices has been assessed at dose rates greater than 2000 cGy/h. Application have been made to a personal dosemeter / dose rate meter to measure the absorbed tissue dose received in the case of acute external irradiation. (D.L.)

  9. Advances in absorbed dose measurement standards at the australian radiation laboratory

    International Nuclear Information System (INIS)

    Boas, J.F.; Hargrave, N.J.; Huntley, R.B.; Kotler, L.H.; Webb, D.V.; Wise, K.N.

    1996-01-01

    The applications of ionising radiation in the medical and industrial fields require both an accurate knowledge of the amount of ionising radiation absorbed by the medium in question and the capability of relating this to National and International standards. The most useful measure of the amount of radiation is the absorbed dose which is defined as the energy absorbed per unit mass. For radiotherapy, the reference medium is water, even though the measurement of the absorbed dose to water is not straightforward. Two methods are commonly used to provide calibrations in absorbed dose to water. The first is the calibration of the chamber in terms of exposure in a Cobalt-60 beam, followed by the conversion by a protocol into dose to water in this and higher energy beams. The other route is via the use of a graphite calorimeter as a primary standard device, where the conversion from absorbed dose to graphite to absorbed dose in water is performed either by theoretical means making use of cavity ionisation theory, or by experiment where the graphite calorimeter and secondary standard ionisation chamber are placed at scaled distances from the source of the radiation beam (known as the Dose-Ratio method). Extensive measurements have been made at Cobalt-60 at ARL using both the exposure and absorbed dose to graphite routes. Agreement between the ARL measurements and those based on standards maintained by ANSTO and NPL is within ± 0.3%. Absorbed dose measurements have also been performed at ARL with photon beams of nominal energy 16 and 19 MeV obtained from the ARL linac. The validity of the protocols at high photon energies, the validity of the methods used to convert from absorbed dose in graphite to absorbed dose in water and the validity of the indices used to specify the beams are discussed. Brief mention will also be made of the establishment of a calibration facility for neutron monitors at ARL and of progress in the development of ERP dosimetry

  10. Advances in absorbed dose measurement standards at the australian radiation laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boas, J.F.; Hargrave, N.J.; Huntley, R.B.; Kotler, L.H.; Webb, D.V.; Wise, K.N. [Australian Radiation Laboratory, Yallambie, VIC (Australia)

    1996-12-31

    The applications of ionising radiation in the medical and industrial fields require both an accurate knowledge of the amount of ionising radiation absorbed by the medium in question and the capability of relating this to National and International standards. The most useful measure of the amount of radiation is the absorbed dose which is defined as the energy absorbed per unit mass. For radiotherapy, the reference medium is water, even though the measurement of the absorbed dose to water is not straightforward. Two methods are commonly used to provide calibrations in absorbed dose to water. The first is the calibration of the chamber in terms of exposure in a Cobalt-60 beam, followed by the conversion by a protocol into dose to water in this and higher energy beams. The other route is via the use of a graphite calorimeter as a primary standard device, where the conversion from absorbed dose to graphite to absorbed dose in water is performed either by theoretical means making use of cavity ionisation theory, or by experiment where the graphite calorimeter and secondary standard ionisation chamber are placed at scaled distances from the source of the radiation beam (known as the Dose-Ratio method). Extensive measurements have been made at Cobalt-60 at ARL using both the exposure and absorbed dose to graphite routes. Agreement between the ARL measurements and those based on standards maintained by ANSTO and NPL is within {+-} 0.3%. Absorbed dose measurements have also been performed at ARL with photon beams of nominal energy 16 and 19 MeV obtained from the ARL linac. The validity of the protocols at high photon energies, the validity of the methods used to convert from absorbed dose in graphite to absorbed dose in water and the validity of the indices used to specify the beams are discussed. Brief mention will also be made of the establishment of a calibration facility for neutron monitors at ARL and of progress in the development of ERP dosimetry.

  11. Neutron absorbed dose in a pacemaker CMOS

    International Nuclear Information System (INIS)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L.

    2012-01-01

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10 -17 Gy per neutron emitted by the source. (Author)

  12. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: fermineutron@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-06-15

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

  13. Analysis of uncertainties in the measurements of absorbed dose to water in a secondary standard dosimetry laboratory (SSDL) 60Cobalt

    International Nuclear Information System (INIS)

    Silva, Cosme Norival Mello da; Rosado, Paulo Henrique Goncalves

    2011-01-01

    The National Metrology Laboratory of Ionizing Radiation (LNMRI) is the laboratory designated by INMETRO in the field of Metrology of ionizing radiation and is a Secondary Standard Dosimetry Laboratory (SSDL). One of its guidelines is to maintain and disseminate LNMRI absorbed dose in water used as a national standard dosimetry in radiotherapy. For this pattern is metrologically acceptable accuracy and uncertainties should be assessed over time. The objective of this study is to analyze the uncertainties involved in determining the absorbed dose rate in water and standard uncertainty of absorbed dose calibration in water from a clinical dosimeter. The largest sources of uncertainty in determining the rate of absorbed dose in water are due to: calibration coefficient of the calibration certificate supplied by the BIPM, electrometer calibration, camber stability over time, variation of pressure and humidity, strong dependence and non-uniformity of the field. The expanded uncertainty is 0.94% for k = 2. For the calibration standard uncertainty of absorbed dose in water of a dosimeter in a clinical a major source of uncertainty is due to the absorbed dose rate in water (0.94%). The value of expanded uncertainty of calibrating a clinical dosimeter is 1.2% for k = 2. (author)

  14. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    International Nuclear Information System (INIS)

    Pereira, Wagner de; Kelecom, Alphonse; Py Junior, Delcy de Azevedo

    2007-01-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10 3 μGy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10 0 μGy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  15. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de [Industrias Nucleares do Brasil S.A. (INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Unidade de Tratamento de Minerios], E-mail: wspereira@inb.gov.br; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-graduacao em Ciencia Ambiental; Py Junior, Delcy de Azevedo [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil). Coordenacao de Protecao Radiologica. Unidade de Concentrado de Uranio], E-mail: Delcy@inb.gov.br

    2007-07-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10{sup 3} {mu}Gy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10{sup 0} {mu}Gy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  16. Absorbed dose determination in external beam radiotherapy. An international code of practice for dosimetry based on standards of absorbed dose to water

    International Nuclear Information System (INIS)

    2000-01-01

    The International Atomic Energy Agency published in 1987 an International Code of Practice entitled 'Absorbed Dose Determination in Photon and Electron Beams' (IAEA Technical Reports Series No. 277 (TRS-277)), recommending procedures to obtain the absorbed dose in water from measurements made with an ionization chamber in external beam radiotherapy. A second edition of TRS-277 was published in 1997 updating the dosimetry of photon beams, mainly kilovoltage X rays. Another International Code of Practice for radiotherapy dosimetry entitled 'The Use of Plane-Parallel Ionization Chambers in High Energy Electron and Photon Beams' (IAEA Technical Reports Series No. 381 (TRS-381)) was published in 1997 to further update TRS-277 and complement it with respect to the area of parallel-plate ionization chambers. Both codes have proven extremely valuable for users involved in the dosimetry of the radiation beams used in radiotherapy. In TRS-277 the calibration of the ionization chambers was based on primary standards of air kerma; this procedure was also used in TRS-381, but the new trend of calibrating ionization chambers directly in a water phantom in terms of absorbed dose to water was introduced. The development of primary standards of absorbed dose to water for high energy photon and electron beams, and improvements in radiation dosimetry concepts, offer the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. The dosimetry of kilovoltage X rays, as well as that of proton and heavy ion beams, interest in which has grown considerably in recent years, can also be based on these standards. Thus a coherent dosimetry system based on standards of absorbed dose to water is possible for practically all radiotherapy beams. Many Primary Standard Dosimetry Laboratories (PSDLs) already provide calibrations in terms of absorbed dose to water at the radiation quality of 60 Co gamma rays. Some laboratories have extended calibrations to high energy photon and

  17. Diamond detector in absorbed dose measurements in high-energy linear accelerator photon and electron beams.

    Science.gov (United States)

    Ravichandran, Ramamoorthy; Binukumar, John Pichy; Al Amri, Iqbal; Davis, Cheriyathmanjiyil Antony

    2016-03-08

    Diamond detectors (DD) are preferred in small field dosimetry of radiation beams because of small dose profile penumbras, better spatial resolution, and tissue-equivalent properties. We investigated a commercially available 'microdiamond' detector in realizing absorbed dose from first principles. A microdiamond detector, type TM 60019 with tandem electrometer is used to measure absorbed doses in water, nylon, and PMMA phantoms. With sensitive volume 0.004 mm3, radius 1.1mm, thickness 1 x10(-3) mm, the nominal response is 1 nC/Gy. It is assumed that the diamond detector could collect total electric charge (nC) developed during irradiation at 0 V bias. We found that dose rate effect is less than 0.7% for changing dose rate by 500 MU/min. The reproducibility in obtaining readings with diamond detector is found to be ± 0.17% (1 SD) (n = 11). The measured absorbed doses for 6 MV and 15 MV photons arrived at using mass energy absorption coefficients and stop-ping power ratios compared well with Nd, water calibrated ion chamber measured absorbed doses within 3% in water, PMMA, and nylon media. The calibration factor obtained for diamond detector confirmed response variation is due to sensitivity due to difference in manufacturing process. For electron beams, we had to apply ratio of electron densities of water to carbon. Our results qualify diamond dosimeter as a transfer standard, based on long-term stability and reproducibility. Based on micro-dimensions, we recommend these detectors for pretreatment dose verifications in small field irradiations like stereotactic treatments with image guidance.

  18. Absorbed dose modeled for a liquid circulating around a Co-60 irradiator

    International Nuclear Information System (INIS)

    Mangussi, J.

    2013-01-01

    A model for the distribution of the absorbed dose in a volume of liquid circulating into an active tank containing a Co-60 irradiator is presented. The absorbed dose, the stir process and the liquid recirculation into the active tank are modeled. The absorbed dose for different fractions of the volume is calculated. The necessary irradiation times for the achievement of the required absorbed dose are evaluated. (author)

  19. Parotid-Absorbed Doses: A Comparison Between Spiral Tomography and Panoramic

    Directory of Open Access Journals (Sweden)

    Ehsan Hekmatian

    2016-07-01

    Full Text Available Background Jaws spiral tomography and panoramic radiography have wide applications in dentistry, and the parotid gland is one of the most sensitive organs of the head and neck. Objectives The aim of this study was to evaluate and compare the parotid-absorbed dose in spiral tomography and panoramic radiographs using a thermoluminescent dosimeter. Materials and Methods A radiation analog dosimetry phantom was placed in a Cranex Tome radiograph device, and a parotid absorbed dose was measured in both techniques. Thermoluminescent dosimeters were placed bilaterally in the parotid region (on the tube side and the opposite side. Spiral tomography dosimetry was done for the upper and lower jaws in the anterior and posterior regions. Each region contained four slices of 2 mm and four slices of 4 mm in thickness. The results were analyzed by a Wilcoxon test. Results For the tube side parotid, the average absorbed doses in spiral tomography of the anterior and posterior parts of the maxilla and mandible, with the 2 mm slice thickness, were 1.70/1.40 and 1.65/1.60 mGy, respectively. The average absorbed doses with the 4mm slices were 1.65/1.70 and 1.75/1.57 mGy, respectively. For the opposite parotid, the average absorbed dose in spiral tomography of the anterior and posterior parts of the maxilla and mandible, with the 2 mm slice thickness, were 1.40/1.30 and 1.40/1.67 mGy, respectively. The average absorbed doses with the 4mm slices were 1.50/1.66 and 1.40/1.50 mGy, respectively. The average absorbed dose of the panoramic radiograph was 1.40 mGy. Conclusions There was no statistically significant difference in the parotid absorbed dose between spiral tomography and a panoramic radiograph (P value = 0.18. The overall results of this study were similar to other studies.

  20. High-temperature absorbed dose measurements in the megagray range

    International Nuclear Information System (INIS)

    Balian, P.; Ardonceau, J.; Zuppiroli, L.

    1988-01-01

    Organic conductors of the tetraselenotetracene family have been tested as ''high-temperature'' absorbed dose dosimeters. They were heated up to 120 0 C and irradiated at this temperature with 1-MeV electrons in order to simulate, in a short time, a much longer γ-ray irradiation. The electric resistance increase of the crystal can be considered a good measurement of the absorbed dose in the range 10 6 Gy to a few 10 8 Gy and presumably one order of magnitude more. This dosimeter also permits on-line (in-situ) measurements of the absorbed dose without removing the sensor from the irradiation site. The respective advantages of organic and inorganic dosimeters at these temperature and dose ranges are also discussed. In this connection, we outline new, but negative, results concerning the possible use of silica as a high-temperature, high-dose dosimeter. (author)

  1. Estimation of absorbed radiation dose rates in wild rodents inhabiting a site severely contaminated by the Fukushima Dai-ichi nuclear power plant accident.

    Science.gov (United States)

    Kubota, Yoshihisa; Takahashi, Hiroyuki; Watanabe, Yoshito; Fuma, Shoichi; Kawaguchi, Isao; Aoki, Masanari; Kubota, Masahide; Furuhata, Yoshiaki; Shigemura, Yusaku; Yamada, Fumio; Ishikawa, Takahiro; Obara, Satoshi; Yoshida, Satoshi

    2015-04-01

    The dose rates of radiation absorbed by wild rodents inhabiting a site severely contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident were estimated. The large Japanese field mouse (Apodemus speciosus), also called the wood mouse, was the major rodent species captured in the sampling area, although other species of rodents, such as small field mice (Apodemus argenteus) and Japanese grass voles (Microtus montebelli), were also collected. The external exposure of rodents calculated from the activity concentrations of radiocesium ((134)Cs and (137)Cs) in litter and soil samples using the ERICA (Environmental Risk from Ionizing Contaminants: Assessment and Management) tool under the assumption that radionuclides existed as the infinite plane isotropic source was almost the same as those measured directly with glass dosimeters embedded in rodent abdomens. Our findings suggest that the ERICA tool is useful for estimating external dose rates to small animals inhabiting forest floors; however, the estimated dose rates showed large standard deviations. This could be an indication of the inhomogeneous distribution of radionuclides in the sampled litter and soil. There was a 50-fold difference between minimum and maximum whole-body activity concentrations measured in rodents at the time of capture. The radionuclides retained in rodents after capture decreased exponentially over time. Regression equations indicated that the biological half-life of radiocesium after capture was 3.31 d. At the time of capture, the lowest activity concentration was measured in the lung and was approximately half of the highest concentration measured in the mixture of muscle and bone. The average internal absorbed dose rate was markedly smaller than the average external dose rate (sampling area was estimated to be approximately 52 μGy h(-1) (1.2 mGy d(-1)), even 3 years after the accident. This dose rate exceeds 0.1-1 mGy d(-1) derived consideration reference level for Reference rat

  2. Radiation absorbed dose estimate for rubidium-82 determined from in vivo measurements in human subjects

    International Nuclear Information System (INIS)

    Ryan, J. W.; Harper, P.V.; Stark, V.S.; Peterson, E.L.; Lathrop, K.A.

    1986-01-01

    Radiation absorbed doses from rubidium-82 injected intravenously were determined in two young men, aged 23 and 27, using a dynamic conjugate counting technique to provide data for the net organ integrated time-activity curves in five organs: kidneys, lungs, liver, heart, and testes. This technique utilized a tungsten collimated Anger camera and the accuracy was validated in a prestwood phantom. The data for each organ were compared with conjugate count rates of a reference Ge-68/Ga-68 standard which had been calibrated against the Rb-82 injected. The effects of attenuation in the body were eliminated. The MIRD method was used to calculate the organ self absorbed doses and the total organ absorbed doses. The mean total absorbed doses were as follows (mrads/mCi injected): kidneys 30.9, heart walls 7.5, lungs 6.0, liver 3.0, testes 2.0 (one subject only), red marrow 1.3, remainder of body 1.3 and, extrapolating to women, ovaries 1.2. This absorbed dose to the kidney is significantly less than the pessimistic estimate of 59.4 mrads/mCi, made assuming instantaneous uptake and complete extraction of activity with no excretion by the kidneys, which receive 20% of the cardiac output. Further, in a 68 year old man the renal self absorbed dose was approximately 40% less than the mean renal self absorbed dose of the younger men. This decrease is probably related to the decline in renal blood flow which occurs with advancing age but other factors may also contribute to the observed difference. 14 references, 4 figures, 2 tables

  3. Electron scattering effects on absorbed dose measurements with LiF-dosemeters

    International Nuclear Information System (INIS)

    Bertilsson, G.

    1975-10-01

    The investigation deals with absorbed dose measurements with solid wall-less dosemeters. Electron scattering complicates both measurement of absorbed dose and its theoretical interpretation. The introduction of the dosemeter in a medium causes perturbations of the radiation field. This perturbation and its effect on the distribution of the absorbed dose inside the dosemeter is studied. Plane-parallel LiF-teflon dosemeters (0.005 - 0.1 g.cm -2 ) are irradiated by a photon beam ( 137 Cs) in different media. The investigation shows that corrections must be made for perturbations caused by electron scattering phenomena. Correction factors are given for use in accurate absorbed dose determinations with thermoluminescent dosemeters. (Auth.)

  4. Dose rate distribution for products irradiated in a semi-industrial irradiation plant. 1st stage

    International Nuclear Information System (INIS)

    Mangussi, J.

    2005-01-01

    The model of the bulk product absorbed dose rate distribution in a semi industrial irradiation plant is presented. In this plant the products are subject to a dynamic irradiation process: single-plaque, single-direction, four-passes. The additional two passes, also one on each side of the plaque, serve to minimize the lateral dose variation as well as the depth-dose non-uniformity. The first stage of this model takes only into account the direct absorbed dose rate; the model outputs are the depth-dose distribution and the lateral-dose distribution. The calculated absorbed dose in the bulk product and its uniformity-ratio after the dynamic irradiation process for different products is compared. The model results are in good agreement with the experimental measurements in a bulk of irradiated product; and the air absorbed dose rate in the irradiation chamber behind the product subject to the dynamic irradiation process. (author) [es

  5. An international intercomparison of absorbed dose measurements for radiation therapy

    International Nuclear Information System (INIS)

    Taiman Kadni; Noriah Mod Ali

    2002-01-01

    Dose intercomparison on an international basis has become an important component of quality assurance measurement i.e. to check the performance of absorbed dose measurements in radiation therapy. The absorbed dose to water measurements for radiation therapy at the SSDL, MINT have been regularly compared through international intercomparison programmes organised by the IAEA Dosimetry Laboratory, Seibersdorf, Austria such as IAEA/WHO TLD postal dose quality audits and the Intercomparison of therapy level ionisation chamber calibration factors in terms of air kerma and absorbed dose to water calibration factors. The results of these intercomparison in terms of percentage deviations for Cobalt 60 gamma radiation and megavoltage x-ray from medical linear accelerators participated by the SSDL-MINT during the year 1985-2001 are within the acceptance limit. (Author)

  6. Dose rate influence in the response of the amber 3042 perspex Dosimeter, batch l

    International Nuclear Information System (INIS)

    Prieto Miranda, E. F.; Barrera Gonzalez, G.

    2001-01-01

    The answer of the dosimetry systems is affected by several factors , as the temperature, humidity, light, concentration of oxygen, dose rate, energy spectrum and one can also add the technological conditions of the irradiation process. It should be known as these factors influence in each one of the different dosimetry systems and this way to minimize their effect in the value of the absorbed dose and to obtain exact values . The objective of this paper is to know the influence of the dose rate in the value of the absorbed dose in the Amber 3042 Perspex dosimeters, Batch L, for different measurement wavelengths, as well as, the relation between the post-irradiation time and the induced specific absorbance value in function of the absorbed dose

  7. Conceptual basis for calculations of absorbed-dose distributions

    International Nuclear Information System (INIS)

    Sinclair, W.K.; Rossi, H.H.; Alsmiller, R.G.; Berger, M.J.; Kellerer, A.M.; Roesch, W.C.; Spencer, L.V.; Zaider, M.A.

    1991-01-01

    The effects of radiation on matter are initiated by processes in which atoms and molecules of the medium are ionized or excited. Over a wide range of conditions, it is an excellent approximation to assume that the average number of ionizations and excitations is proportional to the amount of energy imparted to the medium by ionizing radiation in the volume of interest. The absorbed dose, that is, the average amount of energy imparted to the medium per unit mass, is therefore of central importance for the production of radiation effects, and the calculation of absorbed-dose distributions in irradiated media is the focus of interest of the present report. It should be pointed out, however, that even though absorbed dose is useful as an index relating absorbed energy to radiation effects, it is almost never sufficient; it may have to be supplemented by other information, such as the distributions of the amounts of energy imparted to small sites, the correlation of the amounts of energy imparted to adjacent sites, and so on. Such quantities are termed stochastic quantities. Unless otherwise stated, all quantities considered in this report are non-stochastic. 266 refs., 11 figs., 2 tabs

  8. An absorbed dose calorimeter for IMRT dosimetry

    International Nuclear Information System (INIS)

    Duane, S.; Aldehaybes, M.; Bailey, M.; Lee, N.D.; Thomas, C.G.; Palmans, H.

    2012-01-01

    A new calorimeter for dosimetry in small and complex fields has been built. The device is intended for the direct determination of absorbed dose to water in moderately small fields and in composite fields such as IMRT treatments, and as a transfer instrument calibrated against existing absorbed dose standards in conventional reference conditions. The geometry, materials and mode of operation have been chosen to minimize detector perturbations when used in a water phantom, to give a reasonably isotropic response and to minimize the effects of heat transfer when the calorimeter is used in non-reference conditions in a water phantom. The size of the core is meant to meet the needs of measurement in IMRT treatments and is comparable to the size of the air cavity in a type NE2611 ionization chamber. The calorimeter may also be used for small field dosimetry. Initial measurements in reference conditions and in an IMRT head and neck plan, collapsed to gantry angle zero, have been made to estimate the thermal characteristics of the device, and to assess its performance in use. The standard deviation (estimated repeatability) of the reference absorbed dose measurements was 0.02 Gy (0.6%). (authors)

  9. Multilayer detector for skin absorbed dose measuring

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method for skin dosimetry based on utilization of multilayer detectors and permitting to estimate distribution of absorbed dose by skin depth is described. The detector represents a set of thin sensitive elements separated by tissue-equivalent absorbers. Quantitative evaluation and forecasting the degree of radiation injury of skin are determined by the formula based on determination of the probability of the fact that cells are not destroyed and they can divide further on. The given method ensures a possibility of quantitative evaluation of radiobiological effect and forecasting clinical consequences of skin irradiation by results of corresponding measurements of dose by means of the miultilayer detector

  10. Measurement of absorbed doses near interfaces, and dose mapping using gas chromic dosimetry media. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Rehim, F; Said, F I.A.; Abdel-Fattah, A A [National Centre for Radiation Research and Technology, Atomic Energy Athority, P.O.Box 29 Nasr City, Cairo (Egypt)

    1996-03-01

    Gas chromic dosimetry media is a thin-coated film which has advantages for high-dose radiation dosimetry, and produces high-resolution radiation image for gamma radiation. Therefore, these films were calibrated for the dose range 0.1-50 kGy in terms of increase in absorbance at 600 nm, 400 nm; increase in the area of the absorption spectra in the ranges 395-405 nm and 320-450 nm wave length as a function of absorbed dose in water. The calibrated films were used for measurement of absorbed doses close to metal interface, and dose mapping of the radiation field inside product box during a run for sterilizing surgical gloves at the mega-gamma irradiation facility.7 figs.

  11. Determination of Absorbed Dose Using a Dosimetric Film

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Oane, M.; Badita, E.; Mitru, E.

    2009-01-01

    This paper presents the absorbed dose measurements by means of the irradiated dosimetric reference films. The dose distributions were made by MULTIDATA film densitometer using RTD-4 software, in INFLPR Linear Accelerator Department

  12. 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

  13. Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products

    International Nuclear Information System (INIS)

    Vargas, J.; Vivanco, M.; Castro, E.

    2014-08-01

    In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

  14. Patient absorbed radiation doses estimation related to irradiation anatomy

    International Nuclear Information System (INIS)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes

    2014-01-01

    Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector

  15. Calculation of absorbed doses in sphere volumes around the Mammosite using the Monte Carlo simulation code MCNPX

    International Nuclear Information System (INIS)

    Rojas C, E. L.

    2008-01-01

    The objective of this study is to investigate the changes observed in the absorbed doses in mammary gland tissue when irradiated with a equipment of high dose rate known as Mammosite and introducing material resources contrary to the tissue that constitutes the mammary gland. The modeling study is performed with the code MCNPX, 2005 version, the equipment and the mammary gland and calculating the absorbed doses in tissue when introduced small volumes of air or calcium in the system. (Author)

  16. Dose rate modelled for the outdoors of a gamma irradiation

    International Nuclear Information System (INIS)

    Mangussi, J

    2012-01-01

    A model for the absorbed dose rate calculation on the surroundings of a gamma irradiation plant is developed. In such plants, a part of the radiation emitted upwards reach's the outdoors. The Compton scatterings on the wall of the exhausting pipes through de plant roof and on the outdoors air are modelled. The absorbed dose rate generated by the scattered radiation as far as 200 m is calculated. The results of the models, to be used for the irradiation plant design and for the environmental studies, are showed on graphics (author)

  17. Pain and Mean Absorbed Dose to the Pubic Bone After Radiotherapy Among Gynecological Cancer Survivors

    International Nuclear Information System (INIS)

    Waldenstroem, Ann-Charlotte; Olsson, Caroline; Wilderaeng, Ulrica; Dunberger, Gail; Lind, Helena; Al-Abany, Massoud; Palm, Asa; Avall-Lundqvist, Elisabeth; Johansson, Karl-Axel; Steineck, Gunnar

    2011-01-01

    Purpose: To analyze the relationship between mean absorbed dose to the pubic bone after pelvic radiotherapy for gynecological cancer and occurrence of pubic bone pain among long-term survivors. Methods and Materials: In an unselected, population-based study, we identified 823 long-term gynecological cancer survivors treated with pelvic radiotherapy during 1991-2003. For comparison, we used a non-radiation-treated control population of 478 matched women from the Swedish Population Register. Pain, intensity of pain, and functional impairment due to pain in the pubic bone were assessed with a study-specific postal questionnaire. Results: We analyzed data from 650 survivors (participation rate 79%) with median follow-up of 6.3 years (range, 2.3-15.0 years) along with 344 control women (participation rate, 72 %). Ten percent of the survivors were treated with radiotherapy; ninety percent with surgery plus radiotherapy. Brachytherapy was added in 81%. Complete treatment records were recovered for 538/650 survivors, with dose distribution data including dose-volume histograms over the pubic bone. Pubic bone pain was reported by 73 survivors (11%); 59/517 (11%) had been exposed to mean absorbed external beam doses <52.5 Gy to the pubic bone and 5/12 (42%) to mean absorbed external beam doses ≥52.5 Gy. Thirty-three survivors reported pain affecting sleep, a 13-fold increased prevalence compared with control women. Forty-nine survivors reported functional impairment measured as pain walking indoors, a 10-fold increased prevalence. Conclusions: Mean absorbed external beam dose above 52.5 Gy to the pubic bone increases the occurrence of pain in the pubic bone and may affect daily life of long-term survivors treated with radiotherapy for gynecological cancer.

  18. Absorbed Dose Distribution in a Pulse Radiolysis Optical Cell

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.

    1975-01-01

    When a liquid solution in an optical cell is irradiated by an intense pulsed electron beam, it may be important in the chemical analysis of the solution to know the distribution of energy deposited throughout the cell. For the present work, absorbed dose distributions were measured by thin...... radiochromic dye film dosimeters placed at various depths in a quartz glass pulse radiolysis cell. The cell was irradiated with 30 ns pulses from a field-emission electron accelerator having a broad spectrum with a maximum energy of ≈MeV. The measured three-dimensional dose distributions showed sharp gradients...... in dose at the largest penetration depths in the cell and at the extreme lateral edges of the cell interior near the optical windows. This method of measurement was convenient because of the high spatial resolution capability of the detector and the linearity and absence of dose-rate dependence of its...

  19. Contributions to indoor gamma dose rate from building materials

    International Nuclear Information System (INIS)

    Liu Xionghua; Li Guangming; Yang Xiangdong

    1990-01-01

    In the coures of construction of a building structured with bricks and concrets, the indoor gamma air absorbed dose rates were seperately measured from the floors, brick walls and prefabricated plates of concrets, etc.. It suggested that the indoor gamma dose rates from building materials are mainly attributed to the brick walls and the floors. A little contribution comes from other brilding materials. The dose rates can be calculated through a 4π-infinite thick model with a correction factor of 0.52

  20. Photon spectrum and absorbed dose in brain tumor

    Energy Technology Data Exchange (ETDEWEB)

    Silva S, A. [General Electric Healthcare, Antonio Dovali Jaime 70, Torre A 3er. piso, Col. Santa Fe, 01210 Mexico D. F. (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

    2015-10-15

    Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6 MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is 78.1 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 188 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. (Author)

  1. Photon spectrum and absorbed dose in brain tumor

    International Nuclear Information System (INIS)

    Silva S, A.; Vega C, H. R.; Rivera M, T.

    2015-10-01

    Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6 MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is 78.1 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 188 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. (Author)

  2. Radiation absorbed doses in cephalography

    International Nuclear Information System (INIS)

    Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

    1984-01-01

    Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

  3. Intercomparison of standards of absorbed dose between the USSR and the UK

    Science.gov (United States)

    Berlyand, V. A.; Bregadze, J. I.; Burns, J. E.; Dusautoy, A. R.; Sharpe, P. H. G.

    1991-05-01

    A comparison of national standards of absorbed dose was carried out between the All-Union Research Institute for Physical Technical and Radiotechnical Measurements (VNIIFTRI), USSR, and the National Physical Laboratotry (NPL), UK (United Kingdom). Absorbed dose to water for cobalt 60 gamma radiation was compared by means of Fricke dosimeters and ionization chambers in 1985 and 1986. The primary standards used to derive absorbed dose to water were cavity ionization chambers at NPL and a graphite calorimeter at VNIIFTRI. The ratio of absorbed dose to water, NPL to VNIIFTRI, using Fricke dosimeters was 1.008; using ionization chambers it was 1.007. This agreement is within the estimated uncertainties of the standards and measurement methods.

  4. Model of the dose rate for a semi industrial irradiation plant. Pt. 2

    International Nuclear Information System (INIS)

    Mangusi, Josefina

    2004-01-01

    The second stage of the model for the absorbed dose rate in air for the enclosure of a half-industrialist irradiation plant operating with cobalt-60 sources holden in plan geometry is presented. The sensibility of the model with the treatment of the support structure of the irradiator is analyzed and verified with experimental measurements with good accord. The model of the absorbed dose rate in air in the case of an interposed material between the radioactive sources and the point of interest includes in its calculation a set of secondary radioactive sources created by the Compton scattering of the primary radiation. The accord of the calculated absorbed dose rate and the experimental measured ones is good. The transit dose due to the irradiator moving until its dwell position is also modeled. The isodose curves for a set of irradiator parallel planes are also generated. (author) [es

  5. Determination of the absorbed dose rate to a person exposed to a spent source of {sup 60}Co for radiotherapy; Determinacion de la rapidez de dosis absorbida a una persona expuesta a una fuente gastada de {sup 60}Co para radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Garcia M, T.; Angeles C, A.; Benitez, J. A.; Ruiz C, M. A., E-mail: teodoro.garcia@inin.gob.mx [ININ, Departamento de Proteccion Radiologica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    In this work the analysis of absorbed dose rate to a person in made due to the exposure to a spent source of {sup 60}Co of radiotherapy, which has been removed from its shielding clandestinely to sell the shielding as scrap. During the removal of the source of their shielding the people were necessarily exposed to the field of gamma radiation. The activity of the source is considered to be 2595 Ci at the exposure time and to determine the rate of absorbed dose to different organs and the velocity of effective absorbed dose to which the person (s) who manipulated the source of {sup 60}Co were considered three plausible scenarios of manipulation of the source , through modeling with MCNP5. For the execution of the scenarios and the determination of the absorbed doses, two different phantoms are considered. The results obtained for each scenario show that the dose rates to which the people who manipulated the source without the shielding were exposed are extremely high, and in short time the lethal dose is reached. (Author)

  6. Photon spectrum and absorbed dose in brain tumor.

    Science.gov (United States)

    Vega-Carrillo, Hector Rene; Silva-Sanchez, Angeles; Rivera-Montalvo, Teodoro

    2016-11-01

    Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is and 15.7 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 37.1 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Isoeffective dose: a concept for biological weighting of absorbed dose in proton and heavier-ion therapies

    CERN Document Server

    Wambersie, A; Menzel, H G; Gahbauer, R; DeLuca, P M; Hendry, J H; Jones, D T L

    2011-01-01

    When reporting radiation therapy procedures, International Commission on Radiation Units and Measurements (ICRU) recommends specifying absorbed dose at/in all clinically relevant points and/or volumes. In addition, treatment conditions should be reported as completely as possible in order to allow full understanding and interpretation of the treatment prescription. However, the clinical outcome does not only depend on absorbed dose but also on a number of other factors such as dose per fraction, overall treatment time and radiation quality radiation biology effectiveness (RBE). Therefore, weighting factors have to be applied when different types of treatments are to be compared or to be combined. This had led to the concept of `isoeffective absorbed dose', introduced by ICRU and International Atomic Energy Agency (IAEA). The isoeffective dose D(IsoE) is the dose of a treatment carried out under reference conditions producing the same clinical effects on the target volume as those of the actual treatment. It i...

  8. 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.)

  9. Absorbed bone marrow dose in certain dental radiographic techniques

    International Nuclear Information System (INIS)

    White, S.C.; Rose, T.C.

    1979-01-01

    The absorbed dose of radiation in the bone marrow of the region of the head and neck was measured during intraoral, panoramic, and cephalometric radiography. Panoramic radiography results in a dose a fifth or less than that from an intraoral survey. The use of rectangular collimation reduces the bone marrow absorbed dose from an intraoral survey by about 60%. Comparison of the doses from dental radiography with natural environmental radiation shows that an intraoral set of films results in the same total dose to the bone marrow as 65 days of background exposure. The use of rectangular collimation reduces this value to 25 days. Panoramic radiography results in significantly less irradiation, as it reduces the value to 14 days or fewer. Dental radiography thus involves exposures in the range of variation of natural environmental background values

  10. Measuring the absorbed dose in critical organs during low rate dose brachytherapy with {sup 137} Cs using thermoluminescent dosemeters; Medicion de la dosis absorbida en organos criticos durante braquiterapia de baja tasa de dosis con {sup 137} Cs usando dosimetros termoluminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Torres, A. [UAEM, Fac. de Medicina, 50180 Toluca, Estado de Mexico (Mexico); Gonzalez, P.R. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Furetta, C.; Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico); Andres, U.; Mendez, G. [Centro Estatal de Cancerologia de Tabasco, A. Gregorio Mendez No. 2838, Col. Atasta, 86100 Villahermosa, Tabasco (Mexico)

    2003-07-01

    Intracavitary Brachytherapy is one of the most used methods for the treatment of the cervical-uterine cancer. This treatment consists in the insertion of low rate dose {sup 137}Cs sources into the patient. The most used system for the treatment dose planning is that of Manchester. This planning is based on sources, which are considered fixed during the treatment. However, the experience has shown that, during the treatment, the sources could be displaced from its initial position, changing the dose from that previously prescribed. For this reason, it is necessary to make measurements of the absorbed dose to the surrounding organs (mainly bladder and rectum). This paper presents the results of measuring the absorbed dose using home-made LiF: Mg, Cu, P + Ptfe thermoluminescent dosimeters (TLD). Measurements were carried out in-vivo during 20 minutes at the beginning and at the end of the treatments. Results showed that the absorbed dose to the critical organs vary significantly due to the movement of the patient during the treatment. (Author)

  11. Dose rate on the environment generated by a gamma irradiation plant

    International Nuclear Information System (INIS)

    Mangussi, J.

    2011-01-01

    A model for the absorbed dose rate calculation on the surroundings of a gamma irradiation plant is developed. In such plants, a part of the radiation emitted upwards reach the outdoors. The Compton scatterings on the wall of the exhausting pipes through de plant roof and on the outdoors air are modelled. The absorbed dose rate generated by the scattered radiation reaching the outdoors floor is calculated. The results of the models, to be used for the irradiation plant design and for the environmental studies, are showed on tables and graphics. (author) [es

  12. Kinetics of the absorbed dose formation and the effect of chronic β-irradiation on the cytogenetic characteristics and harvest of barley plants

    International Nuclear Information System (INIS)

    Zyablitskaya, E.Ya.; Kal'chenko, V.A.; Aleksakhin, R.M.; Zuev, N.D.

    1984-01-01

    A study was made of the kinetics of the absorbed dose formation, of the cytogenetic effects and the yield of barley plants growing in the experimental fields artificially contaminated with 90 Sr- 90 Y. It was shown that 70% of the dose absorbed during the vegetation period fall on the 1st and the and stages of organogenesis. The dose absorbed was shown to increase the cytogenetic effects. As calculated per 1 Gy the cytogenetic effects had an inverse relation to the dose rate

  13. Simplified method for creating a density-absorbed dose calibration curve for the low dose range from Gafchromic EBT3 film

    Directory of Open Access Journals (Sweden)

    Tatsuhiro Gotanda

    2016-01-01

    Full Text Available Radiochromic film dosimeters have a disadvantage in comparison with an ionization chamber in that the dosimetry process is time-consuming for creating a density-absorbed dose calibration curve. The purpose of this study was the development of a simplified method of creating a density-absorbed dose calibration curve from radiochromic film within a short time. This simplified method was performed using Gafchromic EBT3 film with a low energy dependence and step-shaped Al filter. The simplified method was compared with the standard method. The density-absorbed dose calibration curves created using the simplified and standard methods exhibited approximately similar straight lines, and the gradients of the density-absorbed dose calibration curves were −32.336 and −33.746, respectively. The simplified method can obtain calibration curves within a much shorter time compared to the standard method. It is considered that the simplified method for EBT3 film offers a more time-efficient means of determining the density-absorbed dose calibration curve within a low absorbed dose range such as the diagnostic range.

  14. Three dimensional measurements of absorbed dose in BNCT by Fricke-gel imaging

    International Nuclear Information System (INIS)

    Gambarini, G.; Agosteo, S.; Marchesi, P.; Nava, E.; Palazzi, P.; Pecci, A.; Rosa, R.; Rosi, G.; Tinti, R.

    2001-01-01

    A method has been studied for absorbed dose imaging and profiling in a phantom exposed to thermal or epithermal neutron fields, also discriminating between various contributions to the absorbed dose. The proposed technique is based on optical imaging of FriXy-gel phantoms, which are proper tissue-equivalent phantoms acting as continuous dosimeters. Convenient modifications in phantom composition allow, from differential measurements, the discrimination of various contributions to the absorbed dose. The dosimetry technique is based on a chemical dosimeter incorporated in a tissue-equivalent gel (Agarose). The chemical dosimeter is a ferrous sulphate solution (which is the main component of the standard Fricke dosimeter) added with a metal ion indicator (Xylenol Orange). The absorbed dose is measured by analysing the variation of gel optical absorption in the visible spectrum, imaged by means of a CCD camera provided with a suitable filter. The technique validity has been tested by irradiating and analysing phantoms in the thermal facility of the fast research reactor TAPIRO (ENEA, Casaccia, Italy). In a cylindrical phantom simulating a head, we have imaged the therapy dose from thermal neutron reactions with 10 B and the dose in healthy tissue not containing boron. In tissue without boron, we have discriminated between the two main contributions to the absorbed dose, which comes from the 1 H(n,γ) 2 H and 14 N(n,p) 14 C reactions. The comparison with the results of other experimental techniques and of simulations reveals that the technique is very promising. A method for the discrimination of fast neutron contribution to the absorbed dose, still in an experimental stage, is proposed too. (author)

  15. Determination of absorbed dose to the lens of eye from external sources

    International Nuclear Information System (INIS)

    Chen Lishu

    1993-01-01

    The methods of determining absorbed dose distributions in human eyeball by means of the experiments and available theories have been reported. A water phantom was built up. The distributions of beta dose were measured by an extrapolation ionization chamber at some depths corresponding to components of human eyeball such as cornea, sclera, anterior chamber and the lens of eye. The ratios among superficial absorbed dose (at 0.07 mm) and average absorbed doses at the depths 1,2,3 mm are obtained. They can be used for confining the deterministic effects of superficial tissues and organs such as the lens of eye for weakly penetrating radiations

  16. Comparison of absorbed dose in the cervix carcinoma therapy by brachytherapy of high dose rate using the conventional planning and Monte Carlo simulation; Comparacao da dose absorvida no tratamento do cancer ginecologico por braquiterapia de alta taxa de dose utilizando o planejamento convencional do tratamento e simulacao de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aneli Oliveira da

    2010-07-01

    This study aims to compare the doses received for patients submitted to brachytherapy High Dose Rate (HDR) brachytherapy, a method of treatment of the cervix carcinoma, performed in the planning system PLATO BPS with the doses obtained by Monte Carlo simulation using the radiation transport code MCNP 5 and one female anthropomorphic phantom based on voxel, the FAX. The implementation of HDR brachytherapy treatment for the cervix carcinoma consists of the insertion of an intrauterine probe and an intravaginal probe (ring or ovoid) and then two radiographs are obtained, anteroposterior (AP) and lateral (LAT) to confirm the position of the applicators in the patient and to allow the treatment planning and the determination of the absorbed dose at points of interest: rectum, bladder, sigmoid and point A, which corresponds anatomically to the crossings of the uterine arteries with ureters The absorbed doses obtained with the code MCNP 5, with the exception of the absorbed dose in the rectum and sigmoid for the simulation considering a point source of {sup 192}Ir, are lower than the absorbed doses from PLATO BPS calculations because the MCNP 5 considers the chemical compositions and densities of FAX body, not considering the medium as water. When considering the Monte Carlo simulation for a source with dimensions equal to that used in the brachytherapy irradiator used in this study, the values of calculated absorbed dose to the bladder, to the rectum, to the right point A and to the left point A were respectively lower than those determined by the treatment planning system in 33.29, 5.01, 22.93 and 19.04%. These values are almost all larger than the maximum acceptable deviation between patient planned and administered doses (5 %). With regard to the rectum and bladder, which are organs that must be protected, the present results are in favor of the radiological protection of patients. The point A, that is on the isodose of 100%, used to tumor treatment, the results

  17. Time improvement of photoelectric effect calculation for absorbed dose estimation

    International Nuclear Information System (INIS)

    Massa, J M; Wainschenker, R S; Doorn, J H; Caselli, E E

    2007-01-01

    Ionizing radiation therapy is a very useful tool in cancer treatment. It is very important to determine absorbed dose in human tissue to accomplish an effective treatment. A mathematical model based on affected areas is the most suitable tool to estimate the absorbed dose. Lately, Monte Carlo based techniques have become the most reliable, but they are time expensive. Absorbed dose calculating programs using different strategies have to choose between estimation quality and calculating time. This paper describes an optimized method for the photoelectron polar angle calculation in photoelectric effect, which is significant to estimate deposited energy in human tissue. In the case studies, time cost reduction nearly reached 86%, meaning that the time needed to do the calculation is approximately 1/7 th of the non optimized approach. This has been done keeping precision invariant

  18. Evaluation of absorbed doses at the interface solid surfaces - tritiated water solutions

    International Nuclear Information System (INIS)

    Postolache, Cristian; Matei, Lidia

    2003-01-01

    Studies concerning the isotopic exchange H/D/T in the system elemental hydrogen -- water and in the presence of platinum metals on hydrophobic supports as catalysts were carried out at ICSI (Institute of Cryogenics and Isotope Separations) - Rm. Valcea, Romania. Due to the very low energy of β-radiation emitted by tritium, the direct measurements of dose absorbed by the isotopic exchange catalyst using classical methods is practically impossible. For this purpose an evaluation model was developed. The volume of tritiated water which can irradiate the catalyst was represented by a hemisphere with the radius equal to the maximal rate of β-radiation emitted by tritium. The catalyst surface is represented by a circle with a 0.2 μm radius and the same centre as the circle of the hemisphere secant plane. Flow rate of absorbed dose is calculated with the relation: d (1/100)(Φ·E m /m), where d = dose flow rate, in rad/s, Φ total radiation flux interacting with the catalyst surface, expressed in erg and m = catalyst weight, in grams. Total flux of available radiation, Φ, was determined as a function of three parameters: a) total flow of tritium β-radiation emitted in the hemisphere of tritiated water, dependent on the volume and radioactive concentration; b) emission coefficient in the direction of the catalyst surface; c) attenuation coefficient (due to self-absorption) of the tritium β-radiation in the tritiated water body. (authors)

  19. Validity of the concept of absorbed dose as a physical quantity

    International Nuclear Information System (INIS)

    Tada, Jun-Ichiro; Katoh, Kazuaki.

    1995-01-01

    The concept of the 'absorbed dose' of ionizing radiation is scrutinized from physical point of view. It is shown that the concept and definition of the quantity in the ICRU system is disqualified as a physical quantity and the absorbed dose can not always be a 'measure of cause' in describing causality relation between radiation and effects on matter. The current absorbed dose depends even on the energy that have already been brought out from the matter, contrary to the intention of introducing the quantity. Trials to remove these difficulties are made. However, it is also shown there still exists an essential problem that cannot be solved by improving the formulation. (author)

  20. The analysis of impact of irregularity in radionuclide coating of scaffold on the distribution of absorbed dose produced by grid of microsources

    Directory of Open Access Journals (Sweden)

    N. A. Nerosin

    2015-01-01

    Full Text Available The impact of irregularity in radionuclide coating of scaffold on the distribution of absorbed dose produced by grid of microsources was analyzed. On engineering software MATHCAD the program for calculation of absorbed dose produced by grid of microsources was created. To verify this algorithm the calculation model for MCNP code was established and represented the area consisted of soft biological tissue or any other tissue in which the grid of microsources was incorporated. Using the developed system the value of possible systematic irregular coating of radioactivity on the microsource’s core was analyzed. The distribution of activity along the surface of microsource was simulated to create distribution of absorbed dose rate corresponding to experimental data on radiation injury. The obtained model of microsource with irregular distribution of activity was compared to conventional microsource with core coated regularly along the entire area of the silver stem by main dosimetry characteristics. The results showed that even for extremely irregular distribution of activity the distribution of dose rate produced by microsource in the tumor area was not substantially different from dose-rate field obtained for microsource with regularly coated activity. The differences in dose rates (up to 10% in areas which were the nearest to the center of the grid were significantly lower than its decline from center to periphery of the grid. For spatial distribution of absorbed dose for specific configuration of microsource set and tracing of curves of equal level by selected cut-off the program SEEDPLAN was developed. The developed program represents precisely enough the spatial distribution of selected configuration set of microsources using results of calculation data for absorbed dose around the single microsource as basic data and may be used for optimal planning of brachytherapy with microsources. 

  1. Mathematical models of tumor growth: translating absorbed dose to tumor control probability

    International Nuclear Information System (INIS)

    Sgouros, G.

    1996-01-01

    Full text: The dose-rate in internal emitter therapy is low and time-dependent as compared to external beam radiotherapy. Once the total absorbed dose delivered to a target tissue is calculated, however, most dosimetric analyses of radiopharmaceuticals are considered complete. To translate absorbed dose estimates obtained for internal emitter therapy to biologic effect, the growth characteristics, repair capacity, and radiosensitivity of the tumor must be considered. Tumor growth may be represented by the Gompertz equation in which tumor cells increase at an exponential growth rate that is itself decreasing at an exponential rate; as the tumor increases in size, the growth rate diminishes. The empirical Gompertz expression for tumor growth may be derived from a mechanistic model in which growth is represented by a balance between tumor-cell birth and loss. The birth rate is assumed to be fixed, while the cell loss rate is time-dependent and increases with tumor size. The birth rate of the tumors may be related to their potential doubling time. Multiple biopsies of individual tumors have demonstrated a heterogeneity in the potential doubling time of tumors. By extending the mechanistic model described above to allow for sub-populations of tumor cells with different birth rates, the effect of kinetic heterogeneity within a tumor may be examined. Model simulations demonstrate that the cell kinetic parameters of a tumor are predicted to change over time and measurements obtained using a biopsy are unlikely to reflect the kinetics of the tumor throughout its growth history. A decrease in overall tumor mass, in which each sub-population is reduced in proportion to its cell number, i.e., the log-kill assumption, leads to re-growth of a tumor that has a greater proliferation rate. Therapy that is linked to the potential doubling time or to the effective proliferation rate of the tumor may lead to re-growth of a tumor that is kinetically unchanged. The simplest model of

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

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1978-01-01

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

  3. Absorbed dose to the skin in radiological examinations of upper and lower gastrointestinal tract

    International Nuclear Information System (INIS)

    Zonca, G.; Brusa, A.; Somigliana, A.; Pasqualotto, C.; Sichirollo, A.E.; Bellomi, M.; Cozzi, G.; Severini, A.

    1995-01-01

    Absorbed doses to the skin in radiological examinations of the upper and lower gastronintestinal tract in conventional and digital radiology are evaluated and compared. Absorbed doses were measured with LiF thermoluminescence dosemeters placed on the lower pelvis, umbilicus and forehead of the patient to evaluate the absorbed dose in and outside the primary beam. On 10 patients a reduction in absorbed dose of about 34% for double contrast barium enema and of 66% for upper gastrointestinal tract examinations was revealed with digital radiography equipment. In our working conditions the lower dose requirement for digital radiography is mainly due to image intensifiers and television chains and also, due to our equipment settings, to the dose reduction with digital spot fluorography compared with conventional spot film radiography. (Author)

  4. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    International Nuclear Information System (INIS)

    Akabani, G.; Poston, J.W. Sr.

    1992-01-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system use relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, Monte Carlo calculations were performed using the code Electron Gamma Shower (EGS4). Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessel sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was or cross fire between blood vessels was assumed. Results are useful in assessing the doses to blood and blood vessel walls for different nuclear medicine procedures

  5. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    International Nuclear Information System (INIS)

    Akabani, G.; Poston, J.W.

    1991-05-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was assumed nor cross fire between vessel was assumed. Results are useful in assessing the dose in blood and blood vessel walls for different nuclear medicine procedures. 6 refs., 6 figs., 5 tabs

  6. Radiation absorbed dose and expected risk in head and neck tissues after thyroid radioiodine therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, A [National Center for Nuclear and Radiation Control, AEA., Cairo (Egypt); Farag, H I [National Cancer instiute, Cairo University, Cairo (Egypt); Saleh, A [Al-hussien Hospital, Al-Azhar University, Cairo (Egypt)

    1997-12-31

    Measurement of absorbed dose in head and neck phantom after applying I-131 therapeutic dose for the treatment of thyroid malignancies was conducted. The measurement were carried out at several sites of phantom using TL dosimeters. The absorbed doses were also measured on the skin of four patients during their administration of I-131 therapeutic doses 1.332 GBq (36 mci) I-131. The measurements were taken over 69 hours exposure at different sites of phantom. The same measurements were carried out on the four patients. At five sites of the patients head and neck, the absorbed dose were measured and compared with that measured on the phantom. The values measured are discussed in the light of the published individual absorbed doses in the organs by ICRP tables. High absorbed doses were absorbed in the different sites of the head and neck during the I-131 therapy (0.14-9.68 mGy/mCi). 3 figs., 2 tabs.

  7. Pain and mean absorbed dose to the pubic bone after radiotherapy among gynecological cancer survivors.

    Science.gov (United States)

    Waldenström, Ann-Charlotte; Olsson, Caroline; Wilderäng, Ulrica; Dunberger, Gail; Lind, Helena; al-Abany, Massoud; Palm, Åsa; Avall-Lundqvist, Elisabeth; Johansson, Karl-Axel; Steineck, Gunnar

    2011-07-15

    To analyze the relationship between mean absorbed dose to the pubic bone after pelvic radiotherapy for gynecological cancer and occurrence of pubic bone pain among long-term survivors. In an unselected, population-based study, we identified 823 long-term gynecological cancer survivors treated with pelvic radiotherapy during 1991-2003. For comparison, we used a non-radiation-treated control population of 478 matched women from the Swedish Population Register. Pain, intensity of pain, and functional impairment due to pain in the pubic bone were assessed with a study-specific postal questionnaire. We analyzed data from 650 survivors (participation rate 79%) with median follow-up of 6.3 years (range, 2.3-15.0 years) along with 344 control women (participation rate, 72 %). Ten percent of the survivors were treated with radiotherapy; ninety percent with surgery plus radiotherapy. Brachytherapy was added in 81%. Complete treatment records were recovered for 538/650 survivors, with dose distribution data including dose-volume histograms over the pubic bone. Pubic bone pain was reported by 73 survivors (11%); 59/517 (11%) had been exposed to mean absorbed external beam doses beam doses ≥ 52.5 Gy. Thirty-three survivors reported pain affecting sleep, a 13-fold increased prevalence compared with control women. Forty-nine survivors reported functional impairment measured as pain walking indoors, a 10-fold increased prevalence. Mean absorbed external beam dose above 52.5 Gy to the pubic bone increases the occurrence of pain in the pubic bone and may affect daily life of long-term survivors treated with radiotherapy for gynecological cancer. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Absorbed Doses to Patients in Nuclear Medicine; Doskatalogen foer nukleaermedicin

    Energy Technology Data Exchange (ETDEWEB)

    Leide-Svegborn, Sigrid; Mattsson, Soeren; Nosslin, Bertil [Universitetssjukhuset MAS, Malmoe (Sweden). Avd. foer radiofysik; Johansson, Lennart [Norrlands Universitetssjukhus, Umeaa (Sweden). Avd. foer radiofysik

    2004-09-01

    The work with a Swedish catalogue of radiation absorbed doses to patients undergoing nuclear medicine investigations has continued. After the previous report in 1999, biokinetic data and dose estimates (mean absorbed dose to various organs and tissues and effective dose) have been produced for a number of substances: {sup 11}C- acetate, {sup 11}C- methionine, {sup 18}F-DOPA, whole antibody labelled with either {sup 99m}Tc, {sup 111}In, {sup 123}I or {sup 131}I, fragment of antibody, F(ab'){sub 2} labelled with either {sup 99m}Tc, {sup 111}In, {sup 123}I or {sup 131}I and fragment of antibody, Fab' labelled with either {sup 99m}Tc, {sup 111}In, {sup 123}I or {sup 131}I. The absorbed dose estimates for these substances have been made from published biokinetic information. For other substances of interest, e.g. {sup 14}C-urea (children age 3-6 years), {sup 14}C-glycocholic acid, {sup 14}C-xylose and {sup 14}C-triolein, sufficient literature data have not been available. Therefore, a large number of measurements on patients and volunteers have been carried out, in order to determine the biokinetics and dosimetry for these substances. Samples of breast milk from 50 mothers, who had been subject to nuclear medicine investigations, have been collected at various times after administration of the radiopharmaceutical to the mother. The activity concentration in the breast milk samples has been measured. The absorbed dose to various organs and tissues and the effective dose to the child who ingests the milk have been determined for 17 different radiopharmaceuticals. Based on these results revised recommendations for interruption of breast-feeding after nuclear medicine investigations are suggested.

  9. Hematological toxicity in radioimmunotherapy is predicted both by the computed absorbed whole body dose (cGy) and by the administered dose (mCi)

    International Nuclear Information System (INIS)

    Marquez, Sheri D.; Knox, Susan J.; Trisler, Kirk D.; Goris, Michael L.

    1997-01-01

    Purpose/Objective: Radioimmunotherapy (RIT) has yielded encouraging response rates in patients with recurrent non-Hodgkin's lymphoma, but myelotoxicity remains the dose limiting factor. Dose optimization is theoretically possible, since a pretreatment biodistribution study with tracer doses allows for a fairly accurate estimate of the whole body (and by implication the bone marrow) dose in patients. It has been shown that the radiation dose as a function of the administered dose varies widely from patient to patient. The pretreatment study could therefore be used to determine the maximum tolerable dose for each individual patient. The purpose of this study was to examine whether the administered dose or the estimated whole body absorbed radiation dose were indeed predictors of bone marrow toxicity. Materials and Methods: We studied two cohorts of patients to determine if the computed integral whole body or marrow dose is predictive of myelotoxicity. The first cohort consisted of 13 patients treated with Yttrium-90 labeled anti-CD20 (2B8) monoclonal antibody. Those patients were treated in a dose escalation protocol, based on the administered dose, without correction for weight or body surface. The computed whole body dose varied from 41 to 129 cGy. The second cohort (6 patients) were treated with Iodine-131 labeled anti-CD20 (B1) antibody. In this group the administered dose was tailored to deliver an estimated 75 cGy whole body dose. The administered dose varied from 54 to 84 mCi of Iodine-131. For each patient, white blood cell count with differential, hemoglobin, hematocrit, and platelet levels were measured before and at regular intervals after RIT was administered. Using linear regression analysis, a relationship between administered dose, absorbed dose and myelotoxicity was determined for each patient cohort. Results: Marrow toxicity was measured by the absolute decrease in white blood cell (DWBC), platelet (DPLAT), and neutrophil (DN) values. In the Yttrium

  10. Radiation absorbed dose from medically administered radiopharmaceuticals

    International Nuclear Information System (INIS)

    Roedler, H.D.; Kaul, A.

    1975-01-01

    The use of radiopharmaceuticals for medical examinations is increasing. Surveys carried out in West Berlin show a 20% average yearly increase in such examinations. This implies an increased genetic and somatic radiation exposure of the population in general. Determination of radiation exposure of the population as well as of individual patients examined requires a knowledge of the radiation dose absorbed by each organ affected by each examination. An extensive survey of the literature revealed that different authors reported widely different dose values for the same defined examination methods and radiopharmaceuticals. The reason for this can be found in the uncertainty of the available biokinetic data for dose calculations and in the application of various mathematical models to describe the kinetics and calculation of organ doses. Therefore, the authors recalculated some of the dose values published for radiopharmaceuticals used in patients by applying biokinetic data obtained from exponential models of usable metabolism data reported in the literature. The calculation of organ dose values was done according to the concept of absorbed fractions in its extended form. For all radiopharmaceuticals used in nuclear medicine the energy dose values for the most important organs (ovaries, testicles, liver, lungs, spleen, kidneys, skeleton, total body or residual body) were recalculated and tabulated for the gonads, skeleton and critical or examined organs respectively. These dose values are compared with those reported in the literature and the reasons for the observed deviations are discussed. On the basis of recalculated dose values for the gonads and bone-marrow as well as on the basis of results of statistical surveys in West Berlin, the genetically significant dose and the somatically (leukemia) significant dose were calculated for 1970 and estimated for 1975. For 1970 the GSD was 0.2 mrad and the LSD was 0.7 mrad. For 1975 the GSD is estimated at < 0.5 mrad and the

  11. The absorbed dose in air of photons generated from secondary cosmic rays at sea level at Nagoya, Japan

    International Nuclear Information System (INIS)

    Akhmad, Y.R.

    1995-01-01

    Investigations have been carried out to determine the absorbed dose in air of photons generated from secondary cosmic radiation at sea level at Nagoya, Japan. To isolate the contribution from cosmic photons, the pulse-height distributions due to μ particles and electrons were eliminated from the observed pulse-height distribution of a measurement with a 3'' diam. spherical NaI(Tl) detector. The pulse height due to μ particles and electrons was inferred from the coincidence technique using two types of scintillation detectors with different sensitivities to photons. To obtain the photon fluence rate for further dose calculation, the pulse-height distribution of cosmic photons was unfolded by the iterative method. The mean and its standard deviation of the absorbed dose in air and fluence rate due to cosmic photons calculated from a one year observation are 2.86±0.05 nGy.h -1 and 0.1342±0.0015 photons.cm -2 .s -1 , respectively. The absorbed dose in air from cosmic photons was 0.5% lower during autumn to winter and 0.6% higher during spring to summer than the mean taken over the year. (author)

  12. Conversion of ionization measurements to radiation absorbed dose in non-water density material

    International Nuclear Information System (INIS)

    El-Khatib, E.; Connors, S.

    1992-01-01

    In bone-equivalent materials two different calculations of absorbed dose are possible: the absorbed dose to soft tissue plastic (polystyrene) within bone-equivalent material and the dose to the bone-equivalent material itself. Both can be calculated from ionization measurements in phantoms. These two calculations result in significantly different doses in a heterogeneous phantom composed of polystyrene and aluminium (a bone substitute). The dose to a thin slab of polystyrene in aluminium is much higher than the dose to the aluminium itself at the same depth in the aluminium. Monte Carlo calculations confirm that the calculation of dose to polystyrene in aluminium can be accurately carried out using existing dosimetry protocols. However, the conversion of ionization measurements to absorbed dose to high atomic number materials cannot be accurately carried out with existing protocols and appropriate conversion factors need to be determined. (author)

  13. Gamma-Dose rate above uranium mineralization areas in western sudan

    International Nuclear Information System (INIS)

    Sam, A.K; Sirelkhatim, D.A; Hassona, R.K.

    2003-01-01

    Absorbed dose rate received from natural external irradiation in uranium mineralisation areas at Uro, Kurun and Jebel Mun was evaluated from the measured activity concentrations of 238 U, 232 Th and 40 K in rock samples.The analyses were performed using alpha-spectrometry and high-resolution gamma-ray spectrometry. A great spatial variability was observed in activity concentration of the primordial radionuclides indicating complexity in geological features. Converses to Jebel Mun, Uro and Kurun deposits exhibit very high U:Th mass ratio. The resulting absorbed dose rate in air as estimated using DRCF's fall within the range of 70-522 (Mun), 569-349 (Uro) and 84-320 n Gy/h (Kurun). At maximum, they correspond to annual effective dose of 0.64, 7.78 and 0.39 mSv, respectively. Uranium is the principal producer of the surface radioactivity at Uro and Kurun as it contributes 99.6% and 95% of the total absorbed dose whereas, in Jebel Mun the cause of radioactive anomaly is due to 40 K and 232 Th. In Uro and Kurun deposits, daughter/parent activity ratios along uranium series, Viz. 234 U: 238 U, 230 Th:U, 210 Po:U, are not differ from the equilibrium value of unity.(Author)

  14. Assessment of human effective absorbed dose of 67 Ga-ECC based on biodistribution rat data.

    Science.gov (United States)

    Shanehsazzadeh, Saeed; Yousefnia, Hassan; Lahooti, Afsaneh; Zolghadri, Samaneh; Jalilian, Amir Reza; Afarideh, Hossien

    2015-02-01

    In a diagnostic context, determination of absorbed dose is required before the introduction of a new radiopharmaceutical to the market to obtain marketing authorization from the relevant agencies. In this work, the absorbed dose of [67 Ga]-ethylenecysteamine cysteine [(67 Ga)ECC] to human organs was determined by using distribution data for rats. For biodistribution data, the animals were sacrificed by CO2 asphyxiation at selected times after injection (0.5, 2 and 48 h, n = 3 for each time interval), then the tissue (blood, heart, lung, brain, intestine, feces, skin, stomach, kidneys, liver, muscle and bone) were removed. The absorbed dose was determined by Medical Internal Radiation Dose (MIRD) method after calculating cumulated activities in each organ. Our prediction shows that a 185-MBq injection of (67)Ga-ECC into the humans might result in an estimated absorbed dose of 0.029 mGy in the whole body. The highest absorbed doses are observed in the spleen and liver with 33.766 and 16.847 mGy, respectively. The results show that this radiopharmaceutical can be a good SPECT tracer since it can be produced easily and also the absorbed dose in each organ is less than permitted absorbed dose.

  15. DETERMINATION OF SUPERFICIAL ABSORBED DOSE FROM EXTERNAL EXPOSURE OF WEAKLY PENETRATING RADIATIONS

    Institute of Scientific and Technical Information of China (English)

    陈丽姝

    1994-01-01

    The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported.The distributions of beta dose were measured by an extrapolation ionization chamber at definite depthes corresponding to some superficial organs and tissues such as the radiosensitive layer of the skin,cornea,sclera,anterior chamber and lens of eyeball.The ratios among superficial absorbed dose D(0.07) and average absorbed doses at the depthes 1,2,3,4,5 and 6mm are also obtained with Cross's methods.They can be used for confining the deterministic effects of some superficial tissues and organs such as the skin and the components of eyeball for weakly penetrating radiations.

  16. 3D calculation of absorbed dose for 131I-targeted radiotherapy: A Monte Carlo study

    International Nuclear Information System (INIS)

    Saeedzadeh, E.; Sarkar, S.; Abbaspour Tehrani-Fard, A.; Ay, M. R.; Khosravi, H. R.; Loudos, G.

    2008-01-01

    Various methods, such as those developed by the Medical Internal Radiation Dosimetry (MIRD) Committee of the Society of Nuclear Medicine or employing dose point kernels, have been applied to the radiation dosimetry of 131 I radionuclide therapy. However, studies have not shown a strong relationship between tumour absorbed dose and its overall therapeutic response, probably due in part to inaccuracies in activity and dose estimation. In the current study, the GATE Monte Carlo computer code was used to facilitate voxel-level radiation dosimetry for organ activities measured in an. 131 I-treated thyroid cancer patient. This approach allows incorporation of the size, shape and composition of organs (in the current study, in the Zubal anthropomorphic phantom) and intra-organ and intra-tumour inhomogeneities in the activity distributions. The total activities of the tumours and their heterogeneous distributions were measured from the SPECT images to calculate the dose maps. For investigating the effect of activity distribution on dose distribution, a hypothetical homogeneous distribution of the same total activity was considered in the tumours. It was observed that the tumour mean absorbed dose rates per unit cumulated activity were 0.65 E-5 and 0.61 E-5 mGY MBq -1 s -1 for the uniform and non-uniform distributions in the tumour, respectively, which do not differ considerably. However, the dose-volume histograms (DVH) show that the tumour non-uniform activity distribution decreases the absorbed dose to portions of the tumour volume. In such a case, it can be misleading to quote the mean or maximum absorbed dose, because overall response is likely limited by the tumour volume that receives low (i.e. non-cytocidal) doses. Three-dimensional radiation dosimetry, and calculation of tumour DVHs, may lead to the derivation of clinically reliable dose-response relationships and therefore may ultimately improve treatment planning as well as response assessment for radionuclide

  17. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  18. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    International Nuclear Information System (INIS)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade

    2009-01-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  19. Evaluation of the absorbed dose to the lungs due to Xe133 and Tc99m (MAA)

    International Nuclear Information System (INIS)

    Vazquez A, M.; Murillo C, F.; Castillo D, C.; Sifuentes D, Y.; Sanchez S, P.; Rojas P, E.; Marquez P, F.

    2015-10-01

    The absorbed dose in lungs of an adult patient has been evaluated using the biokinetics of radiopharmaceuticals containing Xe 133 or Tc 99m (MAA). The absorbed dose was calculated using the MIRD formalism, and the Cristy-and Eckerman lungs model. The absorbed dose in the lungs due to 133 Xe is 0.00104 mGy/MBq. Here, the absorbed dose due to remaining tissue, included in the 133 Xe biokinetics is not significant. The absorbed dose in the lungs, due Tc 99m (MAA), is 0.065 mGy/MBq. Approximately, 4.6% of the absorbed dose is due to organs like liver, kidneys, bladder, and the rest of tissues, included in the Tc 99m biokinetics. Here, the absorbed dose is very significant to be overlooked. The dose contribution is mainly due to photons emitted by the liver. (Author)

  20. Effect of gamma background on the dose absorbed by human embryon and foetus

    International Nuclear Information System (INIS)

    Miloslavov, V.; Doncheva, B.

    1989-01-01

    A method is proposed for calculation of absorbed radiation dose in different stages of human foetus development under normal or increased gamma background. On the base of ICRP-data for critical organ's mass (foetus, placenta, blood, uterus) a formula is given for absorbed dose evaluation of gonads. It is concluded that increased gamma background is insignificant compared to internal irradiation from absorbed radionuclides

  1. Absorbed dose to the patient by computerized whole body X-ray tomography

    International Nuclear Information System (INIS)

    Krauss, O.; Schuhmacher, H.

    1977-01-01

    The absorbed dose to the patient was measured for several medical investigations by computerized whole body scanning. An Alderson-phantom mounted with LiF-TLD was irradiated with a Delta-Scan (Ohio-Nuclear, 120 kV, 30 mA). The integral dose to the brain during a full examination (6 scans, filtration 3 mm Al) was measured to 5x10 -2 J. The maximum absorbed dose at the entrance was found to be 3.2 rd and at the exit 0.6 rd. The dose to the eyes is 0.7 rd and to the thyroid gland 0.03 rd. The integral dose to the trunk (5 scans in the region of liver and kidneys, filtration 6 mm Al) was measured to 5x10 -2 J. The maximum absorbed dose at the entrance was found to be 2.4 rd and at the exit 0.25 rd. The dose to the gonads is less than 2 and 4 mrd if the distance between the last scan and the gonads is more than 15 cm

  2. Measurement of neutron and gamma absorbed doses in phantoms exposed to mixed fields

    International Nuclear Information System (INIS)

    Beraud-Sudreau, E.; Lemaire, G.; Maas, J.

    1985-01-01

    In order to study the dosimetric characteristics of PIN junctions, the absorbed doses measured by junctions and FLi7 in air and water phantoms were compared with the doses measured by classical neutron dosimetry in mixed fields. The validity of the experimental responses of PIN junctions being thus checked and established, neutron and gamma dose distributions in tissue equivalent plastic phantoms (plastinaut) and mammals (piglets) were evaluated as well as the absorbed dose distributions in the pig bone-marrow producing areas. By using correlatively a Monte-Carlo calculation method and applying some simplifying assumptions, the absorbed doses were derived from the spectrum of SILENE's neutrons at various depths inside a cubic water phantom and the results were compared with some from the literature [fr

  3. Absorbed dose to the urinary bladder wall for different radiopharmaceuticals using dynamic S-values

    International Nuclear Information System (INIS)

    Andersson, M.; Minarik, D.; Mattsson, S.; Leide-Svegborn; Johansson, L.

    2015-01-01

    Full text of publication follows. Aim and background: the urinary bladder wall is a radiosensitive organ that can receive a high absorbed dose from radiopharmaceuticals used in diagnostic nuclear medicine. Current dynamic models estimate the photon and electron absorbed dose at the inner surface of the bladder wall. The aim of this work has been to create a more realistic estimation of the mean absorbed dose to the urinary bladder wall from different radiopharmaceuticals. This calculation also uses dynamic specific absorption fractions (SAF) that changes with bladder volume and are gender specific. Materials and Methods: the volume of the urinary bladder content was calculated using a spherical approximation with a urinary inflow of 1.0 ml/min and 0.5 ml/min during day and night time, respectively. The activity in the bladder content was described using a bi-exponential extraction from the body. The absorbed dose to the bladder wall was estimated using linear interpolation of SAF values from different bladder volumes, ranging from 10 ml to 800 ml. Administration of the activity was assumed to start at 09:00 with an initial voiding after 40 minutes and a voiding interval of 3.5 hours during the day. A six hour night gap, starting at midnight, with a voiding right before and after the night period, was used. Calculations were made, with the same assumptions, for an earlier dynamic bladder model and with a static SAF value from the ICRP/ICRU adult reference computational phantoms for a bladder containing 200 ml. Values for the absorbed dose per unit administered activity for 19 commonly used radiopharmaceuticals were calculated, e.g. 18 F-FDG, 99m Tc-pertechnetate, 99m Tc-MAG3 and 123 I-NaI. Results and conclusion: the results of the estimates of the absorbed doses to the inner bladder wall were a factor of ten higher than the estimates mean absorbed doses. The mean absorbed doses to the bladder wall were slightly higher for females than males, due to a smaller female

  4. Effect of dose rate on radical and property of gelatin

    International Nuclear Information System (INIS)

    Geng Shengrong; Chen Yuxia; Zu Xiaoyan; Li Xin; Jiang Hongyou

    2015-01-01

    The gelatin was irradiated respectively in the range of 0-32 kGy by dose rates of 60 Gy/min 60 Co, 480 Gy/min 60 Co and 12000 Gy/min accelerator, and the relationships of the radical character and gelatin property with dose rate were investigated through electron spin resonance (ESR) and gelatin permeation chromatogram. The results show that there is weak ESR signal from unirradiated gelatin, but irradiated one presents typical double peak. The order of ESR signal intensity of gelatin with the same absorbed dosage from high to low is 60 Gy/min 60 Co, 480 Gy/min 60 Co and 12000 Gy/min accelerator. The linear relationship between ESR signal intensity from 60 Co irradiated gelatin and absorbed dose is y= 26.983x 2 +1 641.8x-205.69. The intrinsic viscosity, average relative molecular weight, gelatin strength and breaking elongation of irradiated gelatin from high to low are 480 Gy/min 60 Co, 12000 Gy/min accelerator and 60 Gy/min 60 Co. The protection mechanism of high dose rate radiation on gelatin degradation is that the production of effective long life free radicals reduces. (authors)

  5. Eye lens dosimetry for interventional procedures – Relation between the absorbed dose to the lens and dose at measurement positions

    International Nuclear Information System (INIS)

    Geber, Therese; Gunnarsson, Mikael; Mattsson, Sören

    2011-01-01

    This study investigated the relationship between the absorbed dose to the lens of the eye and the absorbed dose at different measurement positions near the eye of interventional radiologists. It also visualised the dose distribution inside the head, both when protective eyewear were used and without such protection. The best position for an eye lens dosimeter was found to be at the side of the head nearest to the radiation source, close to the eye. Positioning the dosimeter at the eyebrow could lead to an underestimation of the lens dose of as much as 45%. The measured dose distribution showed that the absorbed dose to the eye lenses was high compared to the other parts of the head, which stresses the importance of wearing protective eyewear. However, many models of eyewear were found to be deficient as the radiation could slip through at several places, e.g. at the cheek. The relationship between the absorbed dose to the lens and the kerma-area-product (P KA ) delivered to the patient was also studied.

  6. Radiologist and angiographic procedures. Absorbed radiation dose

    International Nuclear Information System (INIS)

    Tryhus, M.; Mettler, F.A. Jr.; Kelsey, C.

    1987-01-01

    The radiation dose absorbed by the angiographer during angiographic procedures is of vital importance to the radiologist. Nevertheless, most articles on the subject are incomplete, and few measure gonadal dose. In this study, three TLDs were used for each of the following sites: radiologist's eyes, thyroid, gonads with and without shielding apron, and hands. The average dose during carotid angiograms was 2.6, 4.1, 0.4, 4.7, and 7.1 mrads to the eyes, thyroid, gonads with and without .5 mm of lead shielding, and hands, respectively. Average dose during abdominal and peripheral vascular angiographic procedures was 5.2, 7.5, 1.2, 8.5, and 39.9 mrads to the eyes, thyroid, gonads with and without shielding, and hands, respectively. A literature review demonstrates a significant reduction in radiation dose to the angiographer after the advent of automated injectors. Our measured doses for carotid angiography are compatible with contemporary reported values. There was poor correlation with fluoroscopy time and measured dose to the angiographer

  7. Ageing effects of polymers at very low dose-rates

    International Nuclear Information System (INIS)

    Chenion, J.; Armand, X.; Berthet, J.; Carlin, F.; Gaussens, G.; Le Meur, M.

    1987-10-01

    The equipment irradiation dose-rate into the containment is variable from 10 -6 to 10 -4 gray per second for the most exposed materials. During qualification, safety equipments are submitted in France to dose-rates around 0.28 gray per second. This study purpose is to now if a so large irradiation dose-rate increase is reasonable. Three elastomeric materials used in electrical cables, o'rings seals and connectors, are exposed to a very large dose-rates scale between 2.1.10 -4 and 1.4 gray per second, to 49 KGy dose. This work was carried out during 3.5 years. Oxygen consumption measurement of the air in contact with polymer materials, as mechanical properties measurement show that: - at very low dose-rate, oxygen consumption is maximum at the same time (1.4 year) for the three elastomeric samples. Also, mechanical properties simultaneously change with oxygen consumption. At very low dose-rate, for the low irradiation doses, oxygen consumption is at least 10 times more important that it is showed when irradiation is carried out with usual material qualification dose-rate. At very low dose-rate, oxygen consumption decreases when absorbed irradiation dose by samples increases. The polymer samples irradiation dose is not still sufficient (49 KGy) to certainly determine, for the three chosen polymer materials, the reasonable irradiation acceleration boundary during nuclear qualification tests [fr

  8. Staff and patient absorbed doses due to diagnostic nuclear medicine procedures

    International Nuclear Information System (INIS)

    Tabei, F.; Neshandar Asli, I.; Aghamiri, S.M.; Arbabi, K.

    2004-01-01

    Background: annual patient effective dose equivalent can be considered as a quantitative physical parameter describing the activities performed in each nuclear medicine department. annual staff dose equivalent could be also considered as a parameter describing the amount of radiation risk for performing the activities. We calculated the staff to patient dose equivalent ratio to be used as a physical parameter for quantification of ALARA law in nuclear medicine department. Materials and methods: as a part of nationwide study, this paper reports the staff and patient absorbed dose equivalents from diagnostic nuclear medicine examinations performed in four nuclear medicine department during 1999-2002. The type and frequency of examinations in each department were determined directly from hospital medical reports. Staff absorbed doses equivalents were calculated from regular personal dosimeter reports. Results: the total number of examinations increased by 16.7 % during these years. Annual patient collective dose equivalent increased about 13.0 % and the mean effective dose equivalent per exam was 3.61 ± 0.07 mSv. Annual total staff absorbed dose equivalent (total of 24 radiation workers) in four departments increased from 40.45 mSv to 47.81 mSv during four years that indicates an increase of about 20.6 %. The average of annual ratios of staff to patient effective dose equivalents in four departments were 1.83 x 10 -3 , 1.04 x 10 -3 , 3.28 x 10 -3 and 3.24 x 10 -3 , respectively, within a range of 0.9 x 10 -3 - 4.17 x 10 -3 . The mean value of ratios in four years was about 2.24 x 10 -3 ± 1.09 x 10 -3 that indicates the staff dose of about two 1000 th of patient dose. Conclusion: The mean value of ratios in four years was about 1.89 x 10 -3 ± 0.95 x 10 -3 indicating the staff dose of about one 1000 th of the patient dose. The staff to patient absorbed dose equivalent ratio could be used as a quantitative parameter for describing ALARA law in radiation protection and

  9. Evaluation of the absorbed dose in odontological computerized tomography

    International Nuclear Information System (INIS)

    Legnani, Adriano; Schelin, Hugo R.; Rocha, Anna Silvia P.S. da; Khoury, Helen J.

    2011-01-01

    This paper evaluated the absorbed dose at the surface entry known as 'cone beam computed tomography' (CBCT) in odontological computerized tomography. Examination were simulated with CBCT for measurements of dose. A phantom were filled with water, becoming scatter object of radiation. Thermoluminescent dosemeters were positioned on points correspondent to eyes and salivary glands

  10. 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.

  11. 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.

  12. 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

  13. Radiation chemistry of water at low dose rates with emphasis on the energy balance

    International Nuclear Information System (INIS)

    Fletcher, J.W.

    1982-09-01

    There has been considerable interest in absorbed dose water calorimetry. In order to accurately relate the temperature change to the absorbed dose, the energy balance of the overall chemistry of the system must be known. The radiolytic products and their yields are affected by dose rate, dose and added solutes. The yields of the radiolytic products have been calculated using a computer program developed at Atomic Energy of Canada. The chemical energy balance was determined as a function of dose for various dose rates and initial concentrations of hydrogen (H 2 ), oxygen (O 2 ), and hydrogen peroxide (H 2 O 2 ). In solutions containing H 2 O 2 or O 2 and H 2 the chemical reactions were exothermic; in other cases they were endothermic. Approach to equilibrium and equilbrium conditions are discussed

  14. Methodic of the gamma-rays absorbed dose measurements on tooth enamel

    International Nuclear Information System (INIS)

    Linev, S.V.; Muravskij, V.A.; Mashevskij, A.A.; Ugolev, I.I.

    1997-01-01

    The analysis of the metrological aspects of the tooth enamel ESR dosimetry has been done. The sample preparation and measurement methods have been elaborated. The methods have passed metrological certification. The methods include tabletting of the mixture of tooth enamel powder and MnO paramagnetic centres concentration additional standard, two loops of additional irradiation of samples by 1 Gy dose and ESR-spectra measurements, calculation of absorbed dose by maximum likelihood algorithm. The algorithm of dose calculation uses enamel spectrum model with axial anisotropic spin-Hamiltonian based on 126 spectra of enamel samples. The algorithm takes into account spectra of the empty cavity, the tube for a sample, the glue and MnO standard. Certificated ESR-station is based on the ESR-analyser PS-100X. ESR-station provides tooth enamel absorbed dose measurements from 0.05 to 0.25 Gy with error 35%, and from 0.25 to 3 Gy with error 20%. The set of tooth enamel absorbed dose standard samples has been created and certificated for the purposes of ESR-station testing and certification. The set consists of 12 tabletted samples of tooth enamel irradiated by doses from 0.05 to 4 Gy. (authors). 7 refs., 1 tab., 2 figs

  15. Absorbed Doses to Embryo from Intravenous Urography at Selected Radiological Departments in Slovakia

    International Nuclear Information System (INIS)

    Karkus, R.; Nikodemova, D.; Horvathova, M.

    2003-01-01

    Actual legislation used in radiological protection requires quality assurance program for decreasing radiation load of patients from radiological examinations. The information about irradiation of pregnant women is very important, because the embryo is more radiosensitive as adult organism. On the basis of absence of unified calculations or measurements of absorbed doses to embryo from various radiological examinations in Slovakia we present in this study the values of absorbed doses to embryo from intravenous urography at selected radiological departments in Slovakia. Absorbed doses to embryo were obtained by measurement and calculation using the simulation of irradiation of pregnant woman by intravenous urography. The results of our study indicate, that absorbed doses to embryo were at various radiological departments considerably different, depending on type of X-ray machine and different settings of technical parameters of X-ray machine. In accordance with worldwide trend it is necessary to decrease radiation load of patients as low as possible level. Differences in radiation load between radiological departments indicate, that it is necessary to continue in solving of this problem and perform measurements and calculations of absorbed doses to embryo at different types of X-ray machines and at different examinations, where the embryo is in direct beam of X-ray. (author)

  16. Absorbed decay-photon dose analysis of the IVVS/GDC plug in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Leichtle, D.; Serikov, A.; Fischer, U. [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (DE). Inst. for Neutron Physics and Reactor Technology (INR)

    2011-07-01

    The In-Vessel Viewing System (IVVS) and the Glow Discharge Cleaning (GDC) unit share a common port at the equatorial level of the ITER tokamak. The plug consists mainly of the IWS probe, capable of performing the laser-based in-vessel viewing and metrology, the GDC electrode, capable of producing glow discharge in the vacuum vessel during intermediate maintenance and wall conditioning periods, and their respective deployment systems to move the electrodes. The plug extends over a length of about 11 m from the GDC tip to the rear end at the bioshield level. At the present stage of the conceptual design a neutronics analysis has been requested to provide valuable input to the design strategy. To this end, a first assessment has been performed focusing on operational loads on the GDC electrode head in the so-called shielding position and on absorbed decay-photon dose rate levels in the structural components of the entire system. In this contribution we are reporting on the absorbed dose rates after the ITER life time irradiation at several cooling times. Gamma sources from activated materials of the IVVS/GDC and surrounding structures, like blanket, vacuum vessel, toroidal and poloidal field coils, have been taken into account. (orig.)

  17. Absorbed dose measurement by the MIRD system in the 131-I treated Thyroid Cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Woon; Lim, Sang Mu; Kim, Chang Hui; Kim, Ki Sub; Cho, Jong Sio; Jeong, Jin Sung; Park, Heung Kyu; Kwon, Oh Jin [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1995-12-01

    Medical Internal Radiation Dose(MIRD) schema was developed for calculating the absorbed dose from the administrated radiopharmaceuticals. With the biological distribution data and physical properties of the radionuclide, we can estimated the absorbed dose by the MIRD schema. For the thyroid cancer patients received high dose 131-I therapy, the absorbed dose to the bone marrow is limiting factor to the administered dose and the duration of admission is determined by the retained activity in the whole body. To the monitoring of whole body radioactivity, we used Eberline Smart 200 system using ionization chamber as a detector. With the time activity (Author).

  18. Measurement of absorbed dose with a bone-equivalent extrapolation chamber

    International Nuclear Information System (INIS)

    DeBlois, Francois; Abdel-Rahman, Wamied; Seuntjens, Jan P.; Podgorsak, Ervin B.

    2002-01-01

    A hybrid phantom-embedded extrapolation chamber (PEEC) made of Solid Water trade mark sign and bone-equivalent material was used for determining absorbed dose in a bone-equivalent phantom irradiated with clinical radiation beams (cobalt-60 gamma rays; 6 and 18 MV x rays; and 9 and 15 MeV electrons). The dose was determined with the Spencer-Attix cavity theory, using ionization gradient measurements and an indirect determination of the chamber air-mass through measurements of chamber capacitance. The collected charge was corrected for ionic recombination and diffusion in the chamber air volume following the standard two-voltage technique. Due to the hybrid chamber design, correction factors accounting for scatter deficit and electrode composition were determined and applied in the dose equation to obtain absorbed dose in bone for the equivalent homogeneous bone phantom. Correction factors for graphite electrodes were calculated with Monte Carlo techniques and the calculated results were verified through relative air cavity dose measurements for three different polarizing electrode materials: graphite, steel, and brass in conjunction with a graphite collecting electrode. Scatter deficit, due mainly to loss of lateral scatter in the hybrid chamber, reduces the dose to the air cavity in the hybrid PEEC in comparison with full bone PEEC by 0.7% to ∼2% depending on beam quality and energy. In megavoltage photon and electron beams, graphite electrodes do not affect the dose measurement in the Solid Water trade mark sign PEEC but decrease the cavity dose by up to 5% in the bone-equivalent PEEC even for very thin graphite electrodes (<0.0025 cm). In conjunction with appropriate correction factors determined with Monte Carlo techniques, the uncalibrated hybrid PEEC can be used for measuring absorbed dose in bone material to within 2% for high-energy photon and electron beams

  19. Radon concentration, absorbed dose rate in air and concentration of natural radionuclides in soil in the Osaka district of Japan

    International Nuclear Information System (INIS)

    Megumi, K.; Matsunami, T.; Ishiyama, T.; Abe, M.; Kimura, S.; Yamazaki, K.; Tsujimoto, T.

    1992-01-01

    Radon concentrations in outdoor air at 18 sites in the Osaka district, in the central part of Japan's main island, were measured with electrostatic integrating radon monitors which were developed by Y Ikebe et al of the Osaka survey centre as part of a nationwide survey of radon indoors and outdoors in Japan conducted by the National Institute of Radiological Science. The mean radon concentration in outdoor air during 2-month periods was measured over a period of a year and a half. In addition, the absorbed dose rate in air and the concentration of natural radionuclides in soil were measured at 40 sites in Osaka Prefecture which is located in the central part of the Osaka district using thermoluminescence dosemeters and with gamma ray spectrometry, respectively. Radon concentration in outdoor air showed a seasonal pattern, reaching its maximum during the winter and its minimum during the summer, but this variation was not significant at the coastal sites. It was concluded that this variation is correlated with a seasonal wind which blows from the continental interior to the ocean in winter and in the opposite direction in summer, as well as with geographical factors. Radon concentration in outdoor air in the Osaka district ranged from 0.6 to 17.9 Bq.m -3 and mean annual radon concentration in outdoor air at the 18 sites ranged from 2.7 to 6.9 Bq.m -3 . It was discovered that radon concentration in outdoor air decreased with wind speed in both winter and summer. The absorbed dose rate in air ranged from 66 to 114 nGy.h -1 , and the concentration of 226 Ra in soil ranged from 20 to 60 Bq.kg -1 respectively. (author)

  20. Visual indicator of absorbed radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Generalova, V V; Krasovitskii, B M; Vainshtok, B A; Gurskii, M N

    1968-10-15

    A visual indicator of the absorbed doses of ionizing radiation is proposed. The indicator has a polymer base with the addition of a dye. A distinctive feature of the indicator consists of the use of polystyrene as its polymer base with the addition of halogen-containing hydrocarbon and the light-proof dye. Such combination of the radiation-resistant polymer of polystyrene and the light-proof dyestuff makes the proposed indicator highly stable.

  1. Estimate of absorbed dose received by individuals irradiated with neutrons

    International Nuclear Information System (INIS)

    Fonseca, E.S. da; Mauricio, C.L.P.

    1995-01-01

    An innovating methodology is proposed to estimate the absorbed dose received by individuals irradiated with neutrons in an accident, even in the case that the victim is not using any kind of neutron dosemeter. The method combines direct measurements of 24 Na and 32 P activated in the human body. The calculation method was developed using data taken from previously published papers and experimental measurements. Other irradiations results in different neutron spectra prove the validity of the methodology here proposed. Using a whole body counter to measure 24 Na activity, it is possible to evaluate neutron absorbed doses in the order of 140 μGy of very soft (thermal) spectra. For fast neutron fields, the lower limit for neutron dose detection increases, but the present method continues to be very useful in accidents, with higher neutron doses. (author). 5 refs., 1 fig., 4 tabs

  2. Fine structure of the absorbed dose rate monitored in Zagreb, Croatia, in the period 1985-2011.

    Science.gov (United States)

    Babić, D; Senčar, J; Petrinec, B; Marović, G; Bituh, T; Skoko, B

    2013-04-01

    We report on the fine structure of the absorbed dose rate D which was measured and recorded on a daily basis at the Institute for Medical Research and Occupational Health in Zagreb, Croatia, throughout the period 1985-2011. After the Chernobyl accident, D increased steeply by a factor of 3.5, but this is the only prominent feature in the D versus time (t) curve. In the absence of accidental conditions, the D(t) is flat and amounts to 30-35 pGy/s. Despite the apparent plainness of D(t), its Fourier transform reveals several periodic modulations hidden in the noise. Some of the corresponding periods (6 and 12 months) can be related to seasonal atmospheric changes but this is not the case with the other periods identified (9.3, 13.7, 15.7, 20, 31, and 39 months). These are found to agree well with literature data on periodicities in solar activity, which implies that they are most probably linked to variations in the atmospheric production of (7)Be by cosmic rays. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Some comments on the concept of absorbed dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1998-12-01

    The main physical quantity for the evaluation of the induced effects by radiation ionizing is absorbed dose. ICRU report 51 defines this concept as quantity dε divided by dm, where dε is the mean energy imparted by radiation ionizing to matter of mass dm. However, nothing is said about the average operation concerning the stochastic energy imparted ε. Nevertheless, because considers the sum of all changes of rest mass of the involved nuclei and elementary particles in all interactions which occur within the mass (i.e. nuclear reactions and transformations of elementary particles), the average operation can not be done with an equilibrium statistical operator, rather, this has to be defined with a non-equilibrium statistical operator, therefore, absorbed dose is a function dependent on time. Furthermore, we present a discussion to clarify the equilibrium radiation and charged particle equilibrium within the context of thermodynamic equilibrium. (Author)

  4. Some comments on the concept of absorbed dose

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1998-12-15

    The main physical quantity for the evaluation of the induced effects by radiation ionizing is absorbed dose. ICRU report 51 defines this concept as quantity d{epsilon} divided by dm, where d{epsilon} is the mean energy imparted by radiation ionizing to matter of mass dm. However, nothing is said about the average operation concerning the stochastic energy imparted {epsilon}. Nevertheless, because considers the sum of all changes of rest mass of the involved nuclei and elementary particles in all interactions which occur within the mass (i.e. nuclear reactions and transformations of elementary particles), the average operation can not be done with an equilibrium statistical operator, rather, this has to be defined with a non-equilibrium statistical operator, therefore, absorbed dose is a function dependent on time. Furthermore, we present a discussion to clarify the equilibrium radiation and charged particle equilibrium within the context of thermodynamic equilibrium. (Author)

  5. WE-A-17A-01: Absorbed Dose Rate-To-Water at the Surface of a Beta-Emitting Planar Ophthalmic Applicator with a Planar, Windowless Extrapolation Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Riley, A [of Wisconsin Medical Radiation Research Center, Madison, WI (United States); Soares, C [NIST (Retired), Gaithersburg, MD (United States); Micka, J; Culberson, W [University of Wisconsin Medical Radiation Research Center, Madison, WI (United States); DeWerd, L [University of WIMadison/ ADCL, Madison, WI (United States)

    2014-06-15

    Purpose: Currently there is no primary calibration standard for determining the absorbed dose rate-to-water at the surface of β-emitting concave ophthalmic applicators and plaques. Machining tolerances involved in the design of concave window extrapolation chambers are a limiting factor for development of such a standard. Use of a windowless extrapolation chamber avoids these window-machining tolerance issues. As a windowless extrapolation chamber has never been attempted, this work focuses on proof of principle measurements with a planar, windowless extrapolation chamber to verify the accuracy in comparison to initial calibration, which could be extended to the design of a hemispherical, windowless extrapolation chamber. Methods: The window of an extrapolation chamber defines the electrical field, aids in aligning the source parallel to the collector-guard assembly, and decreases the backscatter due to attenuation of lower electron energy. To create a uniform and parallel electric field in this research, the source was made common to the collector-guard assembly. A precise positioning protocol was designed to enhance the parallelism of the source and collector-guard assembly. Additionally, MCNP5 was used to determine a backscatter correction factor to apply to the calibration. With these issues addressed, the absorbed dose rate-to-water of a Tracerlab 90Sr planar ophthalmic applicator was determined using National Institute of Standards and Technology's (NIST) calibration formalism, and the results of five trials with this source were compared to measurements at NIST with a traditional extrapolation chamber. Results: The absorbed dose rate-to-water of the planar applicator was determined to be 0.473 Gy/s ±0.6%. Comparing these results to NIST's determination of 0.474 Gy/s yields a −0.6% difference. Conclusion: The feasibility of a planar, windowless extrapolation chamber has been demonstrated. A similar principle will be applied to developing a

  6. A graphite calorimeter for absolute measurements of absorbed dose to water: application in medium-energy x-ray filtered beams.

    Science.gov (United States)

    Pinto, M; Pimpinella, M; Quini, M; D'Arienzo, M; Astefanoaei, I; Loreti, S; Guerra, A S

    2016-02-21

    The Italian National Institute of Ionizing Radiation Metrology (ENEA-INMRI) has designed and built a graphite calorimeter that, in a water phantom, has allowed the determination of the absorbed dose to water in medium-energy x-rays with generating voltages from 180 to 250 kV. The new standard is a miniaturized three-bodies calorimeter, with a disc-shaped core of 21 mm diameter and 2 mm thickness weighing 1.134 g, sealed in a PMMA waterproof envelope with air-evacuated gaps. The measured absorbed dose to graphite is converted into absorbed dose to water by means of an energy-dependent conversion factor obtained from Monte Carlo simulations. Heat-transfer correction factors were determined by FEM calculations. At a source-to-detector distance of 100 cm, a depth in water of 2 g cm(-2), and at a dose rate of about 0.15 Gy min(-1), results of calorimetric measurements of absorbed dose to water, D(w), were compared to experimental determinations, D wK, obtained via an ionization chamber calibrated in terms of air kerma, according to established dosimetry protocols. The combined standard uncertainty of D(w) and D(wK) were estimated as 1.9% and 1.7%, respectively. The two absorbed dose to water determinations were in agreement within 1%, well below the stated measurement uncertainties. Advancements are in progress to extend the measurement capability of the new in-water-phantom graphite calorimeter to other filtered medium-energy x-ray qualities and to reduce the D(w) uncertainty to around 1%. The new calorimeter represents the first implementation of in-water-phantom graphite calorimetry in the kilovoltage range and, allowing independent determinations of D(w), it will contribute to establish a robust system of absorbed dose to water primary standards for medium-energy x-ray beams.

  7. SU-F-T-16: Experimental Determination of Ionization Chamber Correction Factors for In-Phantom Measurements of Reference Air Kerma Rate and Absorbed Water Dose Rate of Brachytherapy 192Ir Source

    International Nuclear Information System (INIS)

    Chan, M; Lee, V; Wong, M; Leung, R; Law, G; Lee, K; Cheung, S; Tung, S

    2016-01-01

    Purpose: Following the method of in-phantom measurements of reference air kerma rate (Ka) at 100cm and absorbed water dose rate (Dw1) at 1cm of high-dose-rate 192Ir brachytherapy source using 60Co absorbed-dose-to-water calibrated (ND,w,60Co) ionization chamber (IC), we experimentally determined the in-phantom correction factors (kglob) of the PTW30013 (PTW, Freiburg, Germany) IC by comparing the Monte Carlo (MC)-calculated kglob of the other PTW30016 IC. Methods: The Dw1 formalism of in-phantom measurement is: M*ND,w,60Co*(kglob)Dw1, where M is the collected charges, and (kglob)Dw1 the in-phantom Dw1 correction factor. Similarly, Ka is determined by M*ND,w,60Co*(kglob)ka, where (kglob)ka the in-phantom Ka correction factor. Two thimble ICs PTW30013 and another PTW30016 having a ND,w,60Co from the German primary standard laboratory (PTB) were simultaneously exposed to the microselectron 192Ir v2 source at 8cm in a PMMA phantom. A reference well chamber (PTW33004) with a PTB transfer Ka calibration Nka was used for comparing the in-phantom measurements to derive the experimental (kglob)ka factors. We determined the experimental (kglob)Dw1 of the PTW30013 by comparing the PTW30016 measurements with MC-calculated (kglob)Dw1. Results: Ka results of the PTW30016 based on ND,w,60Co and MC-calculated (kglob)ka differ from the well chamber results based on Nka by 1.6% and from the manufacturer by 1.0%. Experimental (kglob)ka factors for the PTW30016 and two other PTW30013 are 0.00683, 0.00681 and 0.00679, and vary <0.5% with 1mm source positioning uncertainty. Experimental (kglob)Dw1 of the PTW30013 ICs are 75.3 and 75.6, and differ by 1.6% from the conversion by dose rate constant from the AAPM report 229. Conclusion: The 1.7% difference between MC and experimental (kglob)ka for the PTW30016 IC is within the PTB 2.5% expanded uncertainty in Ka calibration standard. Using a single IC with ND,w,60Co to calibrate the brachytherapy source and dose output in external

  8. Absorbed dose kernel and self-shielding calculations for a novel radiopaque glass microsphere for transarterial radioembolization.

    Science.gov (United States)

    Church, Cody; Mawko, George; Archambault, John Paul; Lewandowski, Robert; Liu, David; Kehoe, Sharon; Boyd, Daniel; Abraham, Robert; Syme, Alasdair

    2018-02-01

    microspheres based on weighted activities. The shapes of the absorbed dose kernels are dominated at short times postactivation by the contributions of 70 Ga and 72 Ga. Following decay of the short-lived contaminants, the absorbed dose kernel is effectively that of 90 Y. After approximately 1000 h postactivation, the contributions of 85 Sr and 89 Sr become increasingly dominant, though the absorbed dose-rate around the beads drops by roughly four orders of magnitude. The introduction of high atomic number elements for the purpose of increasing radiopacity necessarily leads to the production of radionuclides other than 90 Y in the microspheres. Most of the radionuclides in this study are short-lived and are likely not of any significant concern for this therapeutic agent. The presence of small quantities of longer lived radionuclides will change the shape of the absorbed dose kernel around a microsphere at long time points postadministration when activity levels are significantly reduced. © 2017 American Association of Physicists in Medicine.

  9. Determination of Absorbed Dose to Water for Leksell Gamma Knife Unit

    International Nuclear Information System (INIS)

    Hrsak, H.

    2013-01-01

    Because of geometry of photon beams in Leksell Gamma Knife Unit (LGK), there are several technical problems in applying standard protocols for determination of absorbed dose to water (Dw). Currently, Dw in LGK unit, measured at the center of spherical plastic phantom, is used for dose calculation in LGK radiosurgery. Treatment planning software (LGP TPS) accepts this value as a measurement in water and since plastic phantom has higher electron density than water, this leads to systematic errors in dose calculation. To reduce these errors, a photon attenuation correction (PAC) method was applied. For that purpose, measurements of absorbed dose in a center of three different plastic phantoms with 16 cm diameter (ABS - acrylonitrile butadiene styrene, PMMA - polymethyl metacrylate, PMMA + teflon - polytetrafluoroethylene 5 mm shell) were made with ionization chamber (Semiflex, PTW Freiburg). For measured dose values, PAC to water was applied based on electron density (ED) and equivalent water depths (EWD) of the plastic phantoms. The relation between CT number and ED was determined by measuring CT number of standard CT to ED phantom (CIRS Model 062 Phantom). Absorbed dose in plastic phantoms was 2.5 % lower than calculated dose in water for ABS phantom and more than 5.5 % lower for PMMA and PMMA+teflon phantom. Calculated dose in water showed more consistent values for all three phantoms (max. difference 2.6 %). EWD for human cranial bones and brain has value close to the EWD of ABS phantom, which makes this phantom most suitable for dose measurements in clinical application. In LGK radiosurgery determination of errors related to the difference of phantom materials should not be neglected and measured dose should be corrected before usage for patient treatment dose calculation.(author)

  10. A robust method for determining the absorbed dose to water in a phantom for low-energy photon radiation

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T, E-mail: thorsten.schneider@ptb.de [Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig (Germany)

    2011-06-07

    The application of more and more low-energy photon radiation in brachytherapy-either in the form of low-dose-rate radioactive seeds such as Pd-103 or I-125 or in the form of miniature x-ray tubes-has induced greater interest in determining the absorbed dose to water in water in this energy range. As it seems to be hardly feasible to measure the absorbed dose with calorimetric methods in this low energy range, ionometric methods are the preferred choice. However, the determination of the absorbed dose to water in water by ionometric methods is difficult in this energy range. With decreasing energy, the relative uncertainty of the photon cross sections increases and as the mass energy transfer coefficients show a steep gradient, the spectra of the radiation field must be known precisely. In this work two ionometric methods to determine the absorbed dose to water are evaluated with respect to their sensitivity to the uncertainties of the spectra and of the atomic database. The first is the measurement of the air kerma free in air and the application of an MC-based conversion factor to the absorbed dose to water. The second is the determination of the absorbed dose to water by means of an extrapolation chamber as an integral part of a phantom. In the complementing MC-calculations, two assortments of spectra each of which is based on a separate unfolding procedure were used as well as two kinds of databases: the standard PEGS and the recently implemented NIST database of EGSnrc. Experimental results were obtained by using a parallel-plate graphite extrapolation chamber and a free-air chamber. In the case when the water kerma in a phantom is determined from the measurements of air kerma free in air, differences in the order of 10% were found, according to which the database or the kind of spectrum is used. In contrast to this, for the second method, the differences found were about 0.5%.

  11. Study of radon progeny distribution and radiation dose rate in the atmosphere

    International Nuclear Information System (INIS)

    Fujinami, Naoto

    2009-01-01

    The absorbed dose rate in air of airborne gamma-ray and the concentration of radon progeny in surface air have been observed continuously in Maizuru, Japan. When data observed on fine days were plotted, with dose rate as ordinate and contraction as abscissa, these points traced with a lapse of time illustrated an anticlockwise looping for each day. This result suggests that the variation of absorbed dose rate lags behind that of concentration of radon progeny; this is due to the delay time incurred as the concentration level gradually varies from ground surface to upper air. Radon progeny concentrations in precipitation and in surface air have been observed there in order to study the relationship between the two concentrations and the influence of precipitation patterns on the concentration in precipitation. Results obtained from analysis of the observed data suggest that radon progeny in precipitation originate mainly from scavenging within the cloud (rainout) and not from that below the cloud (washout). (author)

  12. Radioiodine Therapy of Hyperthyroidism. Simplified patient-specific absorbed dose planning

    Energy Technology Data Exchange (ETDEWEB)

    Joensson, Helene

    2003-10-01

    Radioiodine therapy of hyperthyroidism is the most frequently performed radiopharmaceutical therapy. To calculate the activity of {sup 131}I to be administered for giving a certain absorbed dose to the thyroid, the mass of the thyroid and the individual biokinetic data, normally in the form of uptake and biologic half-time, have to be determined. The biologic half-time is estimated from several uptake measurements and the first one is usually made 24 hours after the intake of the test activity. However, many hospitals consider it time-consuming since at least three visits of the patient to the hospital are required (administration of test activity, first uptake measurement, second uptake measurement plus treatment). Instead, many hospitals use a fixed effective half-time or even a fixed administered activity, only requiring two visits. However, none of these methods considers the absorbed dose to the thyroid of the individual patient. In this work a simplified patient-specific method for treating hyperthyroidism is proposed, based on one single uptake measurement, thus requiring only two visits to the hospital. The calculation is as accurate as using the individual biokinetic data. The simplified method is as patient-convenient and time effective as using a fixed effective half-time or a fixed administered activity. The simplified method is based upon a linear relation between the late uptake measurement 4-7 days after intake of the test activity and the product of the extrapolated initial uptake and the effective half-time. Treatments not considering individual biokinetics in the thyroid result in a distribution of administered absorbed dose to the thyroid, with a range of -50 % to +160 % compared to a protocol calculating the absorbed dose to the thyroid of the individual patient. Treatments with a fixed administered activity of 370 MBq will in general administer 250 % higher activity to the patient, with a range of -30 % to +770 %. The absorbed dose to other

  13. Absorbed doses behind bones with MR image-based dose calculations for radiotherapy treatment planning.

    Science.gov (United States)

    Korhonen, Juha; Kapanen, Mika; Keyrilainen, Jani; Seppala, Tiina; Tuomikoski, Laura; Tenhunen, Mikko

    2013-01-01

    Magnetic resonance (MR) images are used increasingly in external radiotherapy target delineation because of their superior soft tissue contrast compared to computed tomography (CT) images. Nevertheless, radiotherapy treatment planning has traditionally been based on the use of CT images, due to the restrictive features of MR images such as lack of electron density information. This research aimed to measure absorbed radiation doses in material behind different bone parts, and to evaluate dose calculation errors in two pseudo-CT images; first, by assuming a single electron density value for the bones, and second, by converting the electron density values inside bones from T(1)∕T(2)∗-weighted MR image intensity values. A dedicated phantom was constructed using fresh deer bones and gelatine. The effect of different bone parts to the absorbed dose behind them was investigated with a single open field at 6 and 15 MV, and measuring clinically detectable dose deviations by an ionization chamber matrix. Dose calculation deviations in a conversion-based pseudo-CT image and in a bulk density pseudo-CT image, where the relative electron density to water for the bones was set as 1.3, were quantified by comparing the calculation results with those obtained in a standard CT image by superposition and Monte Carlo algorithms. The calculations revealed that the applied bulk density pseudo-CT image causes deviations up to 2.7% (6 MV) and 2.0% (15 MV) to the dose behind the examined bones. The corresponding values in the conversion-based pseudo-CT image were 1.3% (6 MV) and 1.0% (15 MV). The examinations illustrated that the representation of the heterogeneous femoral bone (cortex denser compared to core) by using a bulk density for the whole bone causes dose deviations up to 2% both behind the bone edge and the middle part of the bone (diameter bones). This study indicates that the decrease in absorbed dose is not dependent on the bone diameter with all types of bones. Thus

  14. Methods to verify absorbed dose of irradiated containers and evaluation of dosimeters

    International Nuclear Information System (INIS)

    Gao Meixu; Wang Chuanyao; Tang Zhangxong; Li Shurong

    2001-01-01

    The research on dose distribution in irradiated food containers and evaluation of several methods to verify absorbed dose were carried out. The minimum absorbed dose of treated five orange containers was in the top of the highest or in the bottom of lowest container. D max /D min in this study was 1.45 irradiated in a commercial 60 Co facility. The density of orange containers was about 0.391g/cm 3 . The evaluation of dosimeters showed that the PMMA-YL and clear PMMA dosimeters have linear relationship with dose response, and the word NOT in STERIN-125 and STERIN-300 indicators were covered completely at the dosage of 125 and 300 Gy respectively. (author)

  15. Experimental measures of the energy rate absorbed in the aluminium and the comparison with the calculation using factors of dose and carrier of electrons by means of MCNP code

    International Nuclear Information System (INIS)

    Federico, Claudio A.; Vieira, Wilson J.; Rigolon, Leda S.Y.; Geraldo, Luiz P.

    2000-01-01

    In this paper are presented the results of a Monte Carlo calculation for the energy deposition rate in aluminum plates, when a collimated beam of gamma-rays produced by thermal neutrons capture in nickel target passes through them. The absorbed dose rate as a function of the aluminum thickness crossed by the gamma beam has been measured by using CaSO e :Dy thermoluminescent dosimeters. The capture gamma ray beam was extracted from a tangential beam tube of the IPEN's IEA-R1 2MW research reactor. The absorbed dose calculation was performed employing the Monte Carlo N-particle transport code (MCNP) and two methods of calculation: the simulated gamma ray flux multiplied by a dose conversion factor, and the simulated electron flux multiplied by the collision linear energy loss. The calculation results obtained by the electron transport have shown a good agreement with the experimental measurements. For deeper layers (more than 10 mm aluminum thickness), the calculation using the gamma ray flux multiplied by dose conversion factors, as well the calculation employing the electron transport, exhibit the same decreasing trade observed in experimental data, differing by a normalization factor of approximately 1.4. However, for layers nearer the material surface, the calculation using photon flux produces an overestimation of that using the electron transport as well as of the experimental results. (author)

  16. The 1997 determination of the Australian standards of exposure and absorbed dose at 60Co

    International Nuclear Information System (INIS)

    Huntley, R.B.; Boas, J.F.; Van der Gaast, H.

    1998-05-01

    The arrangements for the maintenance of the Australian standards for 60 Co are described in detail. The primary standards are a graphite cavity chamber for exposure/air kerma and a graphite calorimeter for absorbed dose. These secondary standards are described and their responses in corresponding 90 Sr reference sources are reported. Accurate ratios between the Australian Radiation Laboratory (ARL) and Australian Nuclear Science and Technology (ANSTO) 90 Sr reference sources are derived for use in future calibrations. The value of 28.8 years for the half-life of 90 Sr is confirmed. The usefulness of 90 Sr reference source measurements in quality assurance is discussed. The charge sensitivity and linearity of the ANSTO electrometers are reported by two different methods and are compared with previous results. Calibration factors for all the secondary standard ionization chambers are given, in terms of exposure, air kerma and absorbed dose to water. Calibration factors are also given for most of the chambers in terms of absorbed dose to graphite. The methods of deriving the calibration factors are explained in detail, including all the corrections applied to both the primary and secondary standard measurements. Three alternative methods of deriving the absorbed dose to water calibration factors are compared. The reported calibration factors are compared with previous results. Changes in the Australian units of exposure, air kerma and absorbed dose to graphite and water are derived from changes in the corresponding calibration factors. The Australian units of exposure and air kerma have not changed significantly since 1990. The Australian unit of absorbed dose to graphite is now 1.1 % smaller than in 1993 and 1.3 % smaller than in 1990. The Australian unit of absorbed dose to water is now 1.4 % smaller than in 1993, but is only 0.9 % smaller than in 1990. Comparisons of the Australian standards of exposure/air kerma and absorbed dose with those of the Bureau

  17. Graphite calorimeter, the primary standard of absorbed dose at BNM-LNHB

    International Nuclear Information System (INIS)

    Daures, J.; Ostrowsky, A.; Chauvenet, B.

    2002-01-01

    The graphite calorimeter is the standard for absorbed dose to water at BNM-LNHB. The transfer from absorbed dose to graphite to absorbed dose to water is then performed by means of chemical dosimeters and ionisation chamber measurements. Therefore the quality of graphite calorimeter measurements is essential. The present graphite calorimeter is described. The characteristics of this calorimeter are pointed out. Special attention is given to the thermal feedback of the core, which is the main difference with the Domen-type calorimeter. The repeatability and reproducibility of the mean absorbed dose in the calorimeter core are presented in detail. As an example, individual measurements in the 20 MV photon beam from our Saturne 43 linac are given. The y-axis quantity is the mean absorbed dose in the core divided by the reference ionisation chamber charge. Both are normalised to the monitor ionisation chamber charge. The standard deviation (of the distribution itself) is 0.12 % for the first set of measurements performed in 1999. In 2002, for each different series, the standard deviation is 0.03%. The improvement on the 2002 standard deviation is mainly due to the change of the ionisation chamber used for the beam monitoring of the linac. Some benefit also comes from changes on the thermal control and measuring systems (nanovoltmeters, Wheatstone bridges, power supplies, determination of the measuring bridge sensitivity (V/Ω.) ). The maximum difference between the means of the three series is 0.08%. This difference is due to the variation of not only the calorimetric measurements but also of the reference ionisation chamber response, of the position of the assembly and of the monitoring of the beam. The stability of the linac (electron energy, photon beam shape) has to be very good too in order to obtain this global performance. The correction factors necessary to determine the absorbed dose to graphite at the reference point in an homogeneous phantom from the

  18. [Dose rate-dependent cellular and molecular effects of ionizing radiation].

    Science.gov (United States)

    Przybyszewski, Waldemar M; Wideł, Maria; Szurko, Agnieszka; Maniakowski, Zbigniew

    2008-09-11

    The aim of radiation therapy is to kill tumor cells while minimizing damage to normal cells. The ultimate effect of radiation can be apoptotic or necrotic cell death as well as cytogenetic damage resulting in genetic instability and/or cell death. The destructive effects of radiation arise from direct and indirect ionization events leading to peroxidation of macromolecules, especially those present in lipid-rich membrane structures as well as chromatin lipids. Lipid peroxidative end-products may damage DNA and proteins. A characteristic feature of radiation-induced peroxidation is an inverse dose-rate effect (IDRE), defined as an increase in the degree of oxidation(at constant absorbed dose) accompanying a lower dose rate. On the other hand, a low dose rate can lead to the accumulation of cells in G2, the radiosensitive phase of the cell cycle since cell cycle control points are not sensitive to low dose rates. Radiation dose rate may potentially be the main factor improving radiotherapy efficacy as well as affecting the intensity of normal tissue and whole-body side effects. A better understanding of dose rate-dependent biological effects may lead to improved therapeutic intervention and limit normal tissue reaction. The study reviews basic biological effects that depend on the dose rate of ionizing radiation.

  19. Methodology for setting the reference levels in the measurements of the dose rate absorbed in air due to the environmental gamma radiation

    International Nuclear Information System (INIS)

    Dominguez Ley, Orlando; Capote Ferrera, Eduardo; Caveda Ramos, Celia; Alonso Abad, Dolores

    2008-01-01

    Full text: The methodology for setting the reference levels of the measurements of the gamma dose rate absorbed in the air is described. The registration level was obtained using statistical methods. To set the alarm levels, it was necessary to begin with certain affectation level, which activates the investigation operation mode when being reached. It is was necessary to transform this affectation level into values of the indicators selected to set the appearance of an alarm in the network, allowing its direct comparison and at the same time a bigger operability of this one. The affectation level was assumed as an effective dose of 1 mSv/y, which is the international dose limit for public. The conversion factor obtained in a practical way as a consequence of the Chernobyl accident was assumed, converting the value of annual effective dose into values of effective dose rate in air. These factors are the most important in our work, since the main task of the National Network of Environmental Radiological Surveillance of the Republic of Cuba is detecting accidents with a situations regional affectation, and this accident is precisely an example of pollution at this scale. The alarm level setting was based on the results obtained in the first year of the Chernobyl accident. For this purpose, some transformations were achieved. In the final results, a correction factor was introduced depending on the year season the measurement was made. It was taken into account the influence of different meteorological events on the measurement of this indicator. (author)

  20. 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.

  1. Evaluation of the distribution of absorbed dose in child phantoms exposed to diagnostic medical x rays

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W. L.; Poston, J. W.; Warner, G. G.

    1978-04-01

    The purpose of this study was to determine, by theoretical calculation and experimental measurement, the absorbed dose distributions in two heterogeneous phantoms representing one-year- and five-year-old children from typical radiographic examinations for those ages. Theoretical work included the modification of an existing internal dose code which uses Monte Carlo methods to determine doses within the Snyder-Fisher mathematical phantom. A Ge(Li) detector and a pinhole collimator were used to measure x-ray spectra which served as input to the modified Monte Carlo codes which were used to calculate organ doses in children. The calculated and measured tissue-air values were compared for a number of organs. For most organs, the results of the calculated absorbed doses agreed with the measured absorbed doses within twice the coefficient of variation of the calculated value. The absorbed dose to specific organs for several selected radiological examinations are given for one-year-old, five-year-old, and adult phantoms.

  2. Evaluation of the distribution of absorbed dose in child phantoms exposed to diagnostic medical x rays

    International Nuclear Information System (INIS)

    Chen, W.L.; Poston, J.W.; Warner, G.G.

    1978-04-01

    The purpose of this study was to determine, by theoretical calculation and experimental measurement, the absorbed dose distributions in two heterogeneous phantoms representing one-year- and five-year-old children from typical radiographic examinations for those ages. Theoretical work included the modification of an existing internal dose code which uses Monte Carlo methods to determine doses within the Snyder-Fisher mathematical phantom. A Ge(Li) detector and a pinhole collimator were used to measure x-ray spectra which served as input to the modified Monte Carlo codes which were used to calculate organ doses in children. The calculated and measured tissue-air values were compared for a number of organs. For most organs, the results of the calculated absorbed doses agreed with the measured absorbed doses within twice the coefficient of variation of the calculated value. The absorbed dose to specific organs for several selected radiological examinations are given for one-year-old, five-year-old, and adult phantoms

  3. Patient absorbed radiation doses estimation related to irradiation anatomy; Estimativa de dose absorvida pelo paciente relacionada a anatomia irradiada

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes, E-mail: prof.flavio@gmail.com, E-mail: amanda-a-soares@hotmail.com, E-mail: gabriellygkahl@gmail.com [Instituto Federal de Eduacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

    2014-07-01

    Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector.

  4. Skin dose rate conversion factors after contamination with radiopharmaceuticals: influence of contamination area, epidermal thickness and percutaneous absorption

    International Nuclear Information System (INIS)

    Covens, P; Berus, D; Caveliers, V; Struelens, L; Vanhavere, F; Verellen, D

    2013-01-01

    Skin contamination with radiopharmaceuticals can occur during biomedical research and daily nuclear medicine practice as a result of accidental spills, after contact with bodily fluids of patients or by inattentively touching contaminated materials. Skin dose assessment should be carried out by repeated quantification to map the course of the contamination together with the use of appropriate skin dose rate conversion factors. Contamination is generally characterised by local spots on the palmar surface of the hand and complete decontamination is difficult as a result of percutaneous absorption. This specific issue requires special consideration as to the skin dose rate conversion factors as a measure for the absorbed dose rate to the basal layer of the epidermis. In this work we used Monte Carlo simulations to study the influence of the contamination area, the epidermal thickness and the percutaneous absorption on the absorbed skin dose rate conversion factors for a set of 39 medical radionuclides. The results show that the absorbed dose to the basal layer of the epidermis can differ by up to two orders of magnitude from the operational quantity H p (0.07) when using an appropriate epidermal thickness in combination with the effect of percutaneous absorption. (paper)

  5. Estimation of absorbed doses on the basis of cytogenetic methods

    International Nuclear Information System (INIS)

    Shevchenko, V.A.; Rubanovich, A.V.; Snigiryova, G.P.

    1998-01-01

    Long-term studies in the field of radiation cytogenetics have resulted in the discovery of relationship between induction of chromosome aberrations and the type of ionizing radiation, their intensity and dose. This has served as a basis of biological dosimetry as an area of application of the revealed relationship, and has been used in the practice to estimate absorbed doses in people exposed to emergency irradiation. The necessity of using the methods of biological dosimetry became most pressing in connection with the Chernobyl accident in 1986, as well as in connection with other radiation situations that occurred in nuclear industry of the former USSR. The materials presented in our works demonstrate the possibility of applying cytogenetic methods for assessing absorbed doses in populations of different regions exposed to radiation as a result of accidents at nuclear facilities (Chernobyl, the village Muslymovo on the Techa river, the Three Mile Island nuclear power station in the USA where an accident occurred in 1979). Fundamentally, new possibilities for retrospective dose assessment are provided by the FISH-method that permits the assessment of absorbed doses after several decades since the exposure occurred. In addition, the application of this method makes it possible to restore the dynamics of unstable chromosome aberrations (dicentrics and centric rings), which is important for further improvement of the method of biological dosimetry based on the analysis of unstable chromosome aberrations. The purpose of our presentation is a brief description of the cytogenetic methods used in biological dosimetry, consideration of statistical methods of data analysis and a description of concrete examples of their application. (J.P.N.)

  6. Peculiarities of absorbed dose forming in some wild animals in Chornobyl exclusion zone

    Directory of Open Access Journals (Sweden)

    V. A. Gaychenko

    2015-10-01

    Full Text Available Based on field researches conducted in the exclusion zone of the Chernobyl nuclear power plant in the years after the accident, the peculiarities are identified of formation of absorbed doses in animals of different taxonomic and ecological groups that live in conditions of radioactive contamination of ecosystems. It was shown importance of consideration of radiation features on wild animals according to their life cycle, conditions and ways of life. Data were displayed about the importance of different types of irradiation according to the period of stay of the animals in the ground, in burrows and nests. The questions were reviewed about value of external and internal radiation in absorbed dose of different types of wildlife. Results of the calculation of the absorbed dose of bird embryos from egg shell were shown.

  7. Determination of the absorbed dose and dose-distribution in water for low- and medium-energetic photons

    International Nuclear Information System (INIS)

    Bultman, J.H.

    1990-05-01

    The methods to determine the absorbed dose to water for low and medium energy photons were studied. Large differences between the results of these methods exists. So, a research proposition has been made to explain these differences. The goal of this research will be the development of a method to determine the absorbed dose below approximately 400 keV with an ionization chamber calibrated at 60 Co gamma radiation. To explain the differences between the set of methods, some causes were proposed, like the influence of the ionisation chamber on the measurement in water. Also, some methods to determine the factors are proposed. (author). 29 refs

  8. Estimation of the absorbed dose in gamma irradiated food containing bone by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Basfar, A.A.; Abdel Rehim, F.

    1997-01-01

    The use of electron spin resonance (ESR) spectroscopy to accurately evaluate the absorbed dose to radiationprocessed bones (and thus meats) is examined. The exposure of foodstuffs containing bone to a dose of ionizing radiation results in the formation of long lived free radicals which give rise to characteristics ESR signals. The yield of radicals was found to be proportional to absorbed dose. Additive re-irradiation of previously irradiated bone was used to estimate the absorbed dose in the irradiated chicken bone. Simple non-linear rational equation was found to fit to the data and yields good dose estimates for irradiated bone in the range of doses (1.0 - 5.0 kGy). Decay of the ESR signal intensity was monitored at different dose levels (2.0 and 7.0 kGy) up to 22 days. The absorbed dose in irradiated chicken (2.Om 3.0 and 6.0 kGy) was assessed at 2, 6 and 12 days after irradiation. Relatively good results were obtained when measurements were made within the following days (up to 12 days) after irradiation. The ability of the dose additive method to provide accurate dose assessments is tested here

  9. Technique-dependent decrease in thyroid absorbed dose for dental radiography

    International Nuclear Information System (INIS)

    Wood, R.E.; Bristow, R.G.; Clark, G.M.; Nussbaum, C.; Taylor, K.W.

    1989-01-01

    A LiF thermoluminescent dosimetry (TLD) system, calibrated in the tissue of interest with the beam used for experimentation, was employed to investigate dosages (muGy) to the thyroid region of an anthropomorphic phantom resultant from two dental complete-mouth radiographic procedures. Both techniques were compared in terms of dosages associated with combinations of lead apron and thyroid collar shielding while using a 70-kVp or 90-kVp x-ray beam for a 20-film complete-mouth series. Lead shielding significantly decreased the dose to the thyroid using both techniques (p less than 0.05). The use of the 90-kVp beam resulted in a significant reduction in the thyroid absorbed dose when using the bisecting angle technique (p less than 0.05) but caused a significant increase in the thyroid absorbed dose when the paralleling technique was used (p less than 0.05). The implementation of higher kilovoltage techniques in dental offices must therefore be dependent on the radiographic technique employed

  10. Metabolic kinetics and absorbed doses of 137Cs in lactating rats and progeny during suckling

    International Nuclear Information System (INIS)

    Lyaginskaya, A.M.; Osipov, V.A.; Dement'ev, S.I.; Ermalitskij, A.P.

    2000-01-01

    The transfer of 137 Cs with maternal milk to progeny was studied in rats The rats were administered with 25 kBq/g of 137 Cs nitrate (pH = 6) in a single oral dose immediately after delivery. Nonpregnant females served as control. Absorbed doses per activity unit to lactating rats were 23 % lover than to nonlactating ones. Over the suckling period absorbed doses to young rats amounted to about 35 % of the absorbed dose to the nursing female. For nonlactating females the internal dose approximately equalled the sum of doses to the nursing female and young rats. Lactating is the effective way for removal of 1 '3 7 Cs from organism of the rats. Content of 1 '3 7 Cs in lactating rat becomes on 42.9 % lower than in organism of nonlactating rat during period of lactating (near 20 days) [ru

  11. Genetic effects induced by neutrons in Drosophila melanogaster I. Determination of absorbed dose

    International Nuclear Information System (INIS)

    Delfin, A.; Paredes, L.C.; Zambrano, F.; Guzman-Rincon, J.; Urena-Nunez, F.

    2001-01-01

    A method to obtain the absorbed dose in Drosophila melanogaster irradiated in the thermal column facility of the Triga Mark III Reactor has been developed. The method is based on the measurements of neutron activation of gold foils produced by neutron capture to obtain the neutron fluxes. These fluxes, combined with the calculations of kinetic energy released per unit mass, enables one to obtain the absorbed doses in Drosophila melanogaster

  12. Optical fibre temperature sensor technology and potential application in absorbed dose calorimetry

    International Nuclear Information System (INIS)

    Allen, P.D.; Hargrave, N.J.

    1992-09-01

    Optical fibre based sensors are proposed as a potential alternative to the thermistors traditionally used as temperature sensors in absorbed dose calorimetry. The development of optical fibre temperature sensor technology over the last ten years is reviewed. The potential resolution of various optical techniques is assessed with particular reference to the requirements of absorbed dose calorimetry. Attention is drawn to other issues which would require investigation before the development of practical optical fibre sensors for this purpose could occur. 192 refs., 5 tabs., 4 figs

  13. Comparision between the IAEA's protocols (TRS-277 and TRS-398) for absorbed dose determination

    International Nuclear Information System (INIS)

    Bero, M.; Anjak, O.

    2007-12-01

    The aim of this study is to compare between two IAEA's Protocols [IAEA-TRS-277 (1987) and IAEA-TRS-398 (2000)] for Absorbed Dose Determination. Five types (5 Chamber) of commonly used cylindrical ionization chambers (Farmer type, 0.6 cc) were used to check the difference in absorbed dose to water determination for Co-60 beams under reference condition. TLD dosimeter was also used for inter-comparison with IAEA's SSDL. The mean values of the measured absorbed dose were found to be similar in both cases and the relative error D (TRS-398)/D (TRS-277) is found to be approximately less than 0.5% for all chambers used in this study.(authors)

  14. Uncertainty analysis in the determination of absorbed dose in water by Fricke chemical dosimetry

    International Nuclear Information System (INIS)

    Vasconcelos, Fabia; Aguirre, Eder Aguirre

    2016-01-01

    This work studies the calculations of uncertainties and the level of confidence that involves the process for obtaining the dose absorbed in water using the method of Fricke dosimetry, developed at Laboratorio de Ciencias Radiologicas (LCR). Measurements of absorbance of samples Fricke, irradiated and non-irradiated is going to use in order to calculate the respective sensitivity coefficients, along with the expressions of the calculation of Fricke dose and the absorbed dose in water. Those expressions are used for calculating the others sensitivity coefficients from the input variable. It is going to use the combined uncertainty and the expanded uncertainty, with a level of confidence of 95.45%, in order to report the uncertainties of the measurement. (author)

  15. Experimental studies on absorbed dose in radiation sterilization of pharmaceutical preparation

    International Nuclear Information System (INIS)

    Ohnishi, Tokuhiro; Okamoto, Shinichi; Kimura, Syojiro; Taimatsu, Meiko.

    1991-01-01

    For radiation sterilization, it is necessary to decide the irradiation conditions considering a balance between sterilization efficiency and chemical changes of samples by irradiation. These effects may be estimated by the product of two factors (D 10 and G value) and absorbed dose. In this work, it has been found experimentally by using Fricke dosimeter that the absorbed doses of the samples in vessels different in size, material, volume, etc. are not equal under the same gamma-ray irradiation condition. The correction factor from exposure to absorbed dose was estimated to be 6-7% for organic vessels (a polyethylene bag and a polystyrene vial) and a 20-ml glass vial, 9% for a 10-ml glass vial, and 10% for the 5-ml glass vial. These values of the correction factor were confirmed by using the changes of enzymic activity of saccharated powder pepsin preparation. In the cases of using organic vessels and the 10-ml glass vial, G-values for the change of the enzymic activity were calculated to show similar values in the range from 0.79 to 0.82. However, in the case of a small glass vial (5-ml), the value was 0.93. (author)

  16. Effects of body and organ size on absorbed dose: there is no standard patient

    International Nuclear Information System (INIS)

    Poston, J.W.

    1976-01-01

    The problem of estimating the absorbed dose to organs and tissues of the human body due to the presence of a radiopharmaceutical in one or more organs is discussed. Complications are introduced by the fact that the body is not homogeneous and in many cases the organ shapes are not regular. Publications of the MIRD Committee have provided a direct means of estimating the absorbed dose (or absorbed fraction) for a number of radioisotopes. These estimates are based on Monte Carlo calculations for monoenergetic photons distributed uniformly in organs of an adult phantom. The medical physicist finds that his patient does not resemble the adult phantom. In addition, the absorbed fractions for the adult are not reasonable values for the child. This paper examines how these absorbed fraction estimates apply to a nonstandard patient

  17. In-phantom measurement of absorbed dose to water in medium energy x-ray beams

    International Nuclear Information System (INIS)

    Hohlfeld, K.

    1996-01-01

    Absorbed dose values in a water phantom derived by the formalism of the IAEA Code of Practice of Absorbed Dose Determination in Photon and Electron Beams are a few per cent higher than those based on the procedure following e.g. ICRU Report 23. The maximum deviation exceeds 10% at 100 kV tube potential. The correction factor needed to take into account the differences at the calibration in terms of air kerma free in air and at the measurement in the water phantom can be determined in different ways: In comparing the result of the absorbed dose measurement by means of the ionization chambers with an other, preferably fundamental method of measurement of absorbed dose in the water phantom or by evaluating all component parts of the correction factor separately. The values of the perturbation correction factor in the IAEA Code were determined in the former way by comparing against a graphite extrapolation chamber. A review is given on a recent re-evaluation using former values of the extrapolation chamber measurements and on new determinations using an absorbed dose water calorimeter, a method based on calculated and measured air kerma values and a method of combining the component factors to the overall correction factor. Recent results achieved by the different methods are compared and a change of the data of the IAEA Code is recommended. (author). 31 refs, 14 figs, 3 tabs

  18. ''Nonisolated-sensor'' solid polystyrene absorbed dose measurements

    International Nuclear Information System (INIS)

    Zeitz, L.; Laughlin, J.S.

    1982-01-01

    A ''nonisolated-sensor'' solid polystyrene calorimeter was constructed to test the role of thermal diffusion in limiting the length of irradiation time during which temperature measurements with nonisolated sensors could be made sufficiently free of drift for determining dose with radiation fields such as gamma rays, x rays, and high-energy electrons. From measured ratios of dose at 5.0 and 0.5 cm in polystyrene and comparisons to dose measurements with a polystyrene parallel-plate (pancake) ion chamber, it was shown that thermal diffusion is sufficiently small in polystyrene to permit accurate measurements for irradiation periods of less than 20 min. Comparison of the absorbed dose measurements and depth dose ratios with pancake ion chambers and calorimeter showed, that within the precision and accuracy of the two measuring systems, there is close agreement. The nonisolated-sensor solid polystyrene calorimeter has the interesting features of (i) simplicity of construction, (ii) simplicity of operation without vacuum or feedback for temperature control, (iii) capability of simultaneous measurements at several depths and off-axis positions, (iv) the very small thermal defect correction with polystyrene, and (v) operation with the calorimeter in any orientation

  19. Nonisolated-sensor solid polystyrene absorbed dose measurements

    International Nuclear Information System (INIS)

    Zeitz, L.; Laughlin, J.S.

    1982-01-01

    A nonisolated-sensor solid polystyrene calorimeter was constructed to test the role of thermal diffusion in limiting the length of irradiation time during which temperature measurements with nonisolated sensors could be made sufficiently free of drift for determining dose with radiation fields such as gamma rays, x rays, and high-energy electrons. From measured ratios of dose at 5.0 and 0.5 cm in polystyrene and comparisons to dose measurements with a polystyrene parallel-plate (pancake) ion chamber, it was shown that thermal diffusion is sufficiently small in polystyrene to permit accurate measurements for irradiation periods of less than 20 min. Comparison of the absorbed dose measurements and depth dose ratios with pancake ion chambers and calorimeter showed, that within the precision and accuracy of the two measuring systems, there is close agreement. The nonisolated-sensor solid polystyrene calorimeter has the interesting features of (i) simplicity of construction, (ii) simplicity of operation without vacuum or feedback for temperature control, (iii) capability of simultaneous measurements at several depths and off-axis positions, (iv) the very small thermal defect correction with polystyrene, and (v) operation with the calorimeter in any orientation

  20. Evaluation of absorbed dose-distribution in the X-ray or gamma-irradiator for blood products

    International Nuclear Information System (INIS)

    Moriyama, Satoshi; Kurihara, Katsuhiko; Yokokawa, Nobuhiko; Satake, Masahiro; Juji, Takeo

    2001-01-01

    Irradiation of blood products abrogates the proliferation of lymphocytes present in cellular component, which is currently the only accepted methodology to prevent transfusion-associated graft versus host disease (TA-GVHD). A range of irradiation dose levels between 15 Gy and 50 Gy is being used, but the majority of facilities are employing 15 Gy. It should, however, be recognized that the delivered dose in the instrument canister might differ from the actual dose absorbed by the blood bag. This study have evaluated the actual dose distribution under practical conditions where a container was loaded with blood products or water bags, or filled with distilled water. This approach provides data that the maximum attenuation occurred when the container was completely filled with a blood-compatible material. Thus, an error of approximately 20 percent should be considered in the dose measured in the in-air condition. A dose calibration in an in-air condition may lead to substantial underexposure of the blood products. A dose distribution study using adequately prearranged exposure period verified that the absorbed dose of 15 Gy was attained at any point in the container for both linear accelerator and gamma-irradiator. The maximal difference in the absorbed dose between measured points was 1.5- and 1.6-fold for linear accelerator and gamma-irradiator, respectively. In conclusion, using blood-compatible materials, a careful dose calibration study should be employed in which the absorbed dose of 15 Gy is obtained at the point where the lowest dose could be expected. (author)

  1. System for determining absorbed dose and its distribution for high-energy electron radiation

    International Nuclear Information System (INIS)

    Hegewald, H.; Wulff, W.

    1977-01-01

    Taking into account the polarization effect, the dose determination for high-energy electron radiation from particle accelerators depends on the knowledge of the energy dependence of the mass stopping power. Results obtained with thermoluminescent dosemeters agree with theoretical values. For absorbed dose measurements the primary energy of electron radiation has been determined by nuclear photoreactions, and the calculation of the absorbed dose from charge measurements by means of the mass stopping power is described. Thus the calibration of ionization chambers for high-energy electron radiation by absolute measurements with the Faraday cage and chemical dosemeters has become possible. (author)

  2. Review of reconstruction of radiation incident air kerma by measurement of absorbed dose in tooth enamel with EPR

    International Nuclear Information System (INIS)

    Wieser, A.

    2012-01-01

    Electron paramagnetic resonance dosimetry with tooth enamel has been proved to be a reliable method to determine retrospectively exposures from photon fields with minimal detectable doses of 100 mGy or lower, which is lower than achievable with cytogenetic dose reconstruction methods. For risk assessment or validating dosimetry systems for specific radiation incidents, the relevant dose from the incident has to be calculated from the total absorbed dose in enamel by subtracting additional dose contributions from the radionuclide content in teeth, natural external background radiation and medical exposures. For calculating organ doses or evaluating dosimetry systems the absorbed dose in enamel from a radiation incident has to be converted to air kerma using dose conversion factors depending on the photon energy spectrum and geometry of the exposure scenario. This paper outlines the approach to assess individual dose contributions to absorbed dose in enamel and calculate individual air kerma of a radiation incident from the absorbed dose in tooth enamel. (author)

  3. Review of reconstruction of radiation incident air kerma by measurement of absorbed dose in tooth enamel with EPR.

    Science.gov (United States)

    Wieser, A

    2012-03-01

    Electron paramagnetic resonance dosimetry with tooth enamel has been proved to be a reliable method to determine retrospectively exposures from photon fields with minimal detectable doses of 100 mGy or lower, which is lower than achievable with cytogenetic dose reconstruction methods. For risk assessment or validating dosimetry systems for specific radiation incidents, the relevant dose from the incident has to be calculated from the total absorbed dose in enamel by subtracting additional dose contributions from the radionuclide content in teeth, natural external background radiation and medical exposures. For calculating organ doses or evaluating dosimetry systems the absorbed dose in enamel from a radiation incident has to be converted to air kerma using dose conversion factors depending on the photon energy spectrum and geometry of the exposure scenario. This paper outlines the approach to assess individual dose contributions to absorbed dose in enamel and calculate individual air kerma of a radiation incident from the absorbed dose in tooth enamel.

  4. Absorbed dose determination in kilovoltage X-ray synchrotron radiation using alanine dosimeters.

    Science.gov (United States)

    Butler, D J; Lye, J E; Wright, T E; Crossley, D; Sharpe, P H G; Stevenson, A W; Livingstone, J; Crosbie, J C

    2016-12-01

    Alanine dosimeters from the National Physical Laboratory (NPL) in the UK were irradiated using kilovoltage synchrotron radiation at the imaging and medical beam line (IMBL) at the Australian Synchrotron. A 20 × 20 mm 2 area was irradiated by scanning the phantom containing the alanine through the 1 mm × 20 mm beam at a constant velocity. The polychromatic beam had an average energy of 95 keV and nominal absorbed dose to water rate of 250 Gy/s. The absorbed dose to water in the solid water phantom was first determined using a PTW Model 31014 PinPoint ionization chamber traceable to a graphite calorimeter. The alanine was read out at NPL using correction factors determined for 60 Co, traceable to NPL standards, and a published energy correction was applied to correct for the effect of the synchrotron beam quality. The ratio of the doses determined by alanine at NPL and those determined at the synchrotron was 0.975 (standard uncertainty 0.042) when alanine energy correction factors published by Waldeland et al. (Waldeland E, Hole E O, Sagstuen E and Malinen E, Med. Phys. 2010, 37, 3569) were used, and 0.996 (standard uncertainty 0.031) when factors by Anton et al. (Anton M, Büermann L., Phys Med Biol. 2015 60 6113-29) were used. The results provide additional verification of the IMBL dosimetry.

  5. Estimation of human absorbed dose for (166)Ho-PAM: comparison with (166)Ho-DOTMP and (166)Ho-TTHMP.

    Science.gov (United States)

    Vaez-Tehrani, Mahdokht; Zolghadri, Samaneh; Yousefnia, Hassan; Afarideh, Hossein

    2016-10-01

    In this study, the human absorbed dose of holmium-166 ((166)Ho)-pamidronate (PAM) as a potential agent for the management of multiple myeloma was estimated. (166)Ho-PAM complex was prepared at optimized conditions and injected into the rats. The equivalent and effective absorbed doses to human organs after injection of the complex were estimated by radiation-absorbed dose assessment resource and methods proposed by Sparks et al based on rat data. The red marrow to other organ absorbed dose ratios were compared with these data for (166)Ho-DOTMP, as the only clinically used (166)Ho bone marrow ablative agent, and (166)Ho-TTHMP. The highest absorbed dose amounts are observed in the bone surface and bone marrow with 1.11 and 0.903 mGy MBq(-1), respectively. Most other organs would receive approximately insignificant absorbed dose. While (166)Ho-PAM demonstrated a higher red marrow to total body absorbed dose ratio than (166)Ho-1,4,7,10-tetraazacyclo dodecane-1,4,7,10 tetra ethylene phosphonic acid (DOTMP) and (166)Ho-triethylene tetramine hexa (methylene phosphonic acid) (TTHMP), the red marrow to most organ absorbed dose ratios for (166)Ho-TTHMP and (166)Ho-PAM are much higher than the ratios for (166)Ho-DOTMP. The result showed that (166)Ho-PAM has significant characteristics than (166)Ho-DOTMP and therefore, this complex can be considered as a good agent for bone marrow ablative therapy. In this work, two separate points have been investigated: (1) human absorbed dose of (166)Ho-PAM, as a potential bone marrow ablative agent, has been estimated; and (2) the complex has been compared with (166)Ho-DOTMP, as the only clinically used bone marrow ablative radiopharmaceutical, showing significant characteristics.

  6. Multilayer detector for measuring absorbed dose in skin

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method of skin dosimetry using multilayer dosimeters is described that allows the skin-depth distribution of absorbed dose to be estimated. A method of quantitative estimation and prediction of the degree of skin radiation damage using a three-layer dosimeter is demonstrated. Dosimeters are holders of tissue-equivalent material that contain photographic film, a scintillator, thermoluminophor, or any other radiation-sensitive element

  7. 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.

  8. 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

  9. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C. Y.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    The absorbed dose due to neutrons by a Complementary Metal Oxide Semiconductor (CMOS) has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes a patient that must be treated by radiotherapy with a linear accelerator; the pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. When the Linac is working in Bremsstrahlung mode an undesirable neutron field is produced due to photoneutron reactions; these neutrons could damage the CMOS putting the patient at risk during the radiotherapy treatment. In order to estimate the neutron dose in the CMOS a Monte Carlo calculation was carried out where a full radiotherapy vault room was modeled with a W-made spherical shell in whose center was located the source term of photoneutrons produced by a Linac head operating in Bremsstrahlung mode at 18 MV. In the calculations a phantom made of tissue equivalent was modeled while a beam of photoneutrons was applied on the phantom prostatic region using a field of 10 x 10 cm{sup 2}. During simulation neutrons were isotropically transported from the Linac head to the phantom chest, here a 1 {theta} x 1 cm{sup 2} cylinder made of polystyrene was modeled as the CMOS, where the neutron spectrum and the absorbed dose were estimated. Main damages to CMOS are by protons produced during neutron collisions protective cover made of H-rich materials, here the neutron spectrum that reach the CMOS was calculated showing a small peak around 0.1 MeV and a larger peak in the thermal region, both connected through epithermal neutrons. (Author)

  10. The Australian Commonwealth standard of measurement for absorbed radiation dose. Part 1

    International Nuclear Information System (INIS)

    Sherlock, S.L.

    1989-08-01

    As an agent for the Commonwealth Scientific and Industrial Research Organisation, the Australian Nuclear Science and Technology Organisation is responsible for maintenance of the Australian Commonwealth standard of absorbed dose. This standard of measurement has application in radiation therapy dosimetry, which is required for the treatment of cancer patients. This report is the first in a series of reports documenting the absorbed dose standard for photon beams in the range from 1 to 25 MeV. The Urquhart graphite micro-calorimeters, which is used for the determination of absorbed dose under high energy photon beams, has been now placed under computer control. Accordingly, a complete upgrade of the calorimeter systems was performed to allow operation in the hospital. In this report, control and monitoring techniques have been described, with an assessment of the performance achieved being given for 6 and 18 MeV bremsstrahlung beams. Random errors have been reduced to near negligible proportions, while systematic errors have been minimized by achieving true quasi-adiabatic operation. 16 refs., 9 tabs., 11 figs

  11. Preparation of super absorbent by irradiation polymerization

    International Nuclear Information System (INIS)

    Hua Fengjun; Tan Chunhong; Qian Mengping

    1995-01-01

    A kind of absorbent is prepared by gamma-rays irradiated by reversed-phase suspension polymerization. Drying particles have 1400 (g/g) absorbency in de-ionic water. Effects of reactive conditions, e.g.: dose-rate, dose, monomer concentration, degree of monomer neutralization and crosslinking agents on absorbency in de-ionic water are discussed. The cause of absorbing de-ionic water by polymer is related to its network structure and ionic equilibrium in particle. Accordingly, a suit reactive condition is chosen for preparation of hydro gel spheres

  12. The limiting dose rate and its importance in radiation protection

    International Nuclear Information System (INIS)

    Bakkiam, D.; Sonwani, Swetha; Arul Ananthakumar, A.; Mohankumar, Mary N.

    2012-01-01

    The concept of defining a low dose of ionizing radiation still remains unclear. Before attempting to define a low dose, it is more important to define a low-dose rate since effects at low dose-rates are different from those observed at higher dose-rates. Hence, it follows that low dose-rates rather than a low dose is an important criteria to determine radio-biological effects and risk factors i.e. stochastic health effects. Chromosomal aberrations induced by ionizing radiations are well fitted by quadratic model Y= áD + âD 2 + C with the linear coefficient of dose predominating for high LET radiations and low doses of low LET. At higher doses and dose rates of sparsely ionizing radiation, break pairs produced by inter-track action leads to the formation of exchange type aberrations and is dependent on dose rate. Whereas at lower doses and dose rates, intra-track action produces break pairs and resulting aberrations are in direct proportion to absorbed dose and independent of dose rate. The dose rate at which inter-track ceases to be observable and where intra-track action effectively becomes the sole contributor of lesion-pair formation is referred to as limiting dose rate (LDR). Once the LDR is reached further reduction in dose rates will not affect the slope of DR since breaks produced by independent charged particle tracks are widely separated in time to interact with each other for aberration yield. This linear dependency is also noticed for acute exposures at very low doses. Existing reports emphasizes the existence of LDR likely to be e6.3cGyh -1 . However no systematic studies have been conducted so far to determine LDR. In the present investigation DR curves were constructed for the dose rates 0.002 and 0.003 Gy/min and to define LDR at which a coefficient approaches zero. Extrapolation of limiting low dose rate data can be used to predict low dose effects regardless of dose rate and its definition ought to serve as a useful index for studies pertaining

  13. Estimation of the absorbed dose in radiation-processed food. Pt.2

    International Nuclear Information System (INIS)

    Desrosiers, M.F.

    1991-01-01

    The use of electron paramagnetic resonance spectroscopy to accurately evaluate the absorbed dose to radiation-processed bones (and thus meats) is examined. Additive re-irradiation of the bone produces a reproducible response function which can be used to evaluate the initial dose by back-extrapolation. It was found that an exponential fit (vs linear or polynomial) to the data provides improved accuracy of the estimated dose. These data as well as the protocol for the additive dose method are presented. (author)

  14. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons

    International Nuclear Information System (INIS)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internal contamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy 109 Cd conversion electrons, working with a 4 π proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin 109 Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  15. Time- and dose rate-related effects of internal 177Lu exposure on gene expression in mouse kidney tissue

    International Nuclear Information System (INIS)

    Schüler, Emil; Rudqvist, Nils; Parris, Toshima Z.; Langen, Britta; Spetz, Johan; Helou, Khalil; Forssell-Aronsson, Eva

    2014-01-01

    Introduction: The kidneys are the dose-limiting organs in some radionuclide therapy regimens. However, the biological impact of internal exposure from radionuclides is still not fully understood. The aim of this study was to examine the effects of dose rate and time after i.v. injection of 177 LuCl 3 on changes in transcriptional patterns in mouse kidney tissue. Methods: To investigate the effect of dose rate, female Balb/c nude mice were i.v. injected with 11, 5.6, 1.6, 0.8, 0.30, and 0 MBq of 177 LuCl 3 , and killed at 3, 6, 24, 48, 168, and 24 hours after injection, respectively. Furthermore, the effect of time after onset of exposure was analysed using mice injected with 0.26, 2.4, and 8.2 MBq of 177 LuCl 3 , and killed at 45, 90, and 140 days after injection. Global transcription patterns of irradiated kidney cortex and medulla were assessed and enriched biological processes were determined from the regulated gene sets using Gene Ontology terms. Results: The average dose rates investigated were 1.6, 0.84, 0.23, 0.11 and 0.028 mGy/min, with an absorbed dose of 0.3 Gy. At 45, 90 and 140 days, the absorbed doses were estimated to 0.3, 3, and 10 Gy. In general, the number of differentially regulated transcripts increased with time after injection, and decreased with absorbed dose for both kidney cortex and medulla. Differentially regulated transcripts were predominantly involved in metabolic and stress response-related processes dependent on dose rate, as well as transcripts associated with metabolic and cellular integrity at later time points. Conclusion: The observed transcriptional response in kidney tissue was diverse due to difference in absorbed dose, dose rate and time after exposure. Nevertheless, several transcripts were significantly regulated in all groups despite differences in exposure parameters, which may indicate potential biomarkers for exposure of kidney tissue

  16. Absorbed doses for patients undergoing panoramic radiography, cephalometric radiography and CBCT

    Directory of Open Access Journals (Sweden)

    Małgorzata Wrzesień

    2017-10-01

    Full Text Available Objectives: Contemporary dental radiology offers a wide spectrum of imaging methods but it also contributes to an increase in the participation of dental radiological diagnosis in the patient’s exposure to ionizing radiation. The aim of this study is to determine the absorbed doses of the brain, spinal column, thyroid and eye lens for patients during panoramic radiography, cephalometric radiography and cone beam computed tomography (CBCT. Material and Methods: The thermoluminescent dosimetry and anthropomorphic phantom was used for measuring the doses. The 15 panoramic, 4 cephalometric and 4 CBCT exposures were performed by placing high-sensitivity thermoluminescent detectors (TLD in 18 anatomical points of the phantom. Results: The maximum absorbed dose recorded during performed measurements corresponds to the point representing the brainstem and it is 10 mGy. The dose value recorded by the TLD placed in the thyroid during CBCT imaging in relation to the panoramic radiography differs by a factor of 13.5. Conclusions: Cone beam computed tomography, in comparison with panoramic or cephalometric imaging technique, provides higher radiation doses to the patients. Int J Occup Med Environ Health 2017;30(5:705–713

  17. Global shutdown dose rate maps for a DEMO conceptual design

    International Nuclear Information System (INIS)

    Leichtle, D.; Pereslavtsev, P.; Sanz, J.; Catalan, J.P.; Juarez, R.

    2015-01-01

    Highlights: • Application of R2S-method on high-resolution full torus sector mesh for DEMO. • Absorbed dose rates after shutdown for a variely of RH equipment at typical locations. • Idenification of radiation levels at several port based locations. - Abstract: For the calculations of highly reliable shutdown dose rate (SDR) maps in fusion devices like a DEMO plant, the Rigorous-2-step (R2S) method is nowadays routinely applied using high-resolution decay gamma sources from initial high-resolution neutron flux meshes activating all materials in the system. This approach has been utilized in the present paper with the objective to provide SDR results relevant for RH systems of a conceptual DEMO design developed in the EU. The primary objective was to assess specific locations of interest for RH equipment inside the vessel and along the extension of maintenance ports. To this end, a provisional DEMO MCNP model has been used, featuring HCLL-type blankets, tungsten/copper divertor, manifolds, vacuum vessel with ports and toroidal field coils. The operational scenario assumed 2.1 GW fusion power and a life-time of 20 years with plant availability of 30%, where removable parts will be extracted after 5.2 years. Results of absorbed dose rate distributions for several relevant materials are presented and discussed in terms of the different contributions from the various activated components.

  18. Global shutdown dose rate maps for a DEMO conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    Leichtle, D., E-mail: dieter.leichtle@f4e.europa.eu [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pereslavtsev, P. [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Sanz, J.; Catalan, J.P.; Juarez, R. [Universidad Nacional de Educación a Distancia(UNED), E.T.S. Ingenieros Industriales, C/ Juan del Rosal 12, 28040 Madrid (Spain)

    2015-10-15

    Highlights: • Application of R2S-method on high-resolution full torus sector mesh for DEMO. • Absorbed dose rates after shutdown for a variely of RH equipment at typical locations. • Idenification of radiation levels at several port based locations. - Abstract: For the calculations of highly reliable shutdown dose rate (SDR) maps in fusion devices like a DEMO plant, the Rigorous-2-step (R2S) method is nowadays routinely applied using high-resolution decay gamma sources from initial high-resolution neutron flux meshes activating all materials in the system. This approach has been utilized in the present paper with the objective to provide SDR results relevant for RH systems of a conceptual DEMO design developed in the EU. The primary objective was to assess specific locations of interest for RH equipment inside the vessel and along the extension of maintenance ports. To this end, a provisional DEMO MCNP model has been used, featuring HCLL-type blankets, tungsten/copper divertor, manifolds, vacuum vessel with ports and toroidal field coils. The operational scenario assumed 2.1 GW fusion power and a life-time of 20 years with plant availability of 30%, where removable parts will be extracted after 5.2 years. Results of absorbed dose rate distributions for several relevant materials are presented and discussed in terms of the different contributions from the various activated components.

  19. Absorbed dose in fibrotic microenvironment models employing Monte Carlo simulation

    International Nuclear Information System (INIS)

    Zambrano Ramírez, O.D.; Rojas Calderón, E.L.; Azorín Vega, E.P.; Ferro Flores, G.; Martínez Caballero, E.

    2015-01-01

    The presence or absence of fibrosis and yet more, the multimeric and multivalent nature of the radiopharmaceutical have recently been reported to have an effect on the radiation absorbed dose in tumor microenvironment models. Fibroblast and myofibroblast cells produce the extracellular matrix by the secretion of proteins which provide structural and biochemical support to cells. The reactive and reparative mechanisms triggered during the inflammatory process causes the production and deposition of extracellular matrix proteins, the abnormal excessive growth of the connective tissue leads to fibrosis. In this work, microenvironment (either not fibrotic or fibrotic) models composed of seven spheres representing cancer cells of 10 μm in diameter each with a 5 μm diameter inner sphere (cell nucleus) were created in two distinct radiation transport codes (PENELOPE and MCNP). The purpose of creating these models was to determine the radiation absorbed dose in the nucleus of cancer cells, based on previously reported radiopharmaceutical retain (by HeLa cells) percentages of the 177 Lu-Tyr 3 -octreotate (monomeric) and 177 Lu-Tyr 3 -octreotate-AuNP (multimeric) radiopharmaceuticals. A comparison in the results between the PENELOPE and MCNP was done. We found a good agreement in the results of the codes. The percent difference between the increase percentages of the absorbed dose in the not fibrotic model with respect to the fibrotic model of the codes PENELOPE and MCNP was found to be under 1% for both radiopharmaceuticals. (authors)

  20. Peculiarities of absorbed dose forming in some wild animals in Chornobyl,y exclusion zone

    International Nuclear Information System (INIS)

    Gaychenko, V.A.; Krainiuk, O.Yu.

    2015-01-01

    Based on field researches conducted in the exclusion zone of the Chernobyl nuclear power plant in the years after the accident, identified the peculiarities of formation absorbed doses in animals of different taxonomic and ecological groups that live in conditions of radioactive contamination of ecosystems. Was shown importance of consideration of radiation features on wild animals according to their life cycle, conditions and ways of life. Was displayed data about the importance of different types of irradiation according to the period of stay the animals in the ground, in burrows and nests. Was reviewed the questions about value of external and internal radiation in absorbed dose of different types of wildlife. Was shown the results of the calculation of the absorbed dose of bird embryos from egg shell

  1. The 1997 determination of the Australian standards of exposure and absorbed dose at {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Huntley, R.B.; Boas, J.F. [Australian Radiation Laboratory, Yallambie, VIC (Australia); Van der Gaast, H. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1998-05-01

    The arrangements for the maintenance of the Australian standards for {sup 60}Co are described in detail. The primary standards are a graphite cavity chamber for exposure/air kerma and a graphite calorimeter for absorbed dose. These secondary standards are described and their responses in corresponding {sup 90}Sr reference sources are reported. Accurate ratios between the Australian Radiation Laboratory (ARL) and Australian Nuclear Science and Technology (ANSTO) {sup 90}Sr reference sources are derived for use in future calibrations. The value of 28.8 years for the half-life of {sup 90}Sr is confirmed. The usefulness of {sup 90}Sr reference source measurements in quality assurance is discussed. The charge sensitivity and linearity of the ANSTO electrometers are reported by two different methods and are compared with previous results. Calibration factors for all the secondary standard ionization chambers are given, in terms of exposure, air kerma and absorbed dose to water. Calibration factors are also given for most of the chambers in terms of absorbed dose to graphite. The methods of deriving the calibration factors are explained in detail, including all the corrections applied to both the primary and secondary standard measurements. Three alternative methods of deriving the absorbed dose to water calibration factors are compared. The reported calibration factors are compared with previous results. Changes in the Australian units of exposure, air kerma and absorbed dose to graphite and water are derived from changes in the corresponding calibration factors. The Australian units of exposure and air kerma have not changed significantly since 1990. The Australian unit of absorbed dose to graphite is now 1.1 % smaller than in 1993 and 1.3 % smaller than in 1990. The Australian unit of absorbed dose to water is now 1.4 % smaller than in 1993, but is only 0.9 % smaller than in 1990. Comparisons of the Australian standards of exposure/air kerma and absorbed dose with

  2. Determination of absorbed dose in reactors

    International Nuclear Information System (INIS)

    1971-01-01

    There are many areas in the use and operation of research reactors where the absorbed dose and the neutron fluence are required. These include work on the determination of the radiolytic stability of the coolant and moderator and on the determination of radiation damage in structural materials, and reactor experiments involving radiation chemistry and radiation biology. The requirements range from rough estimates of the total heating due to radiation to precise values specifying the contributions of gamma rays, thermal neutrons and fast neutrons. To meet all these requirements a variety of experimental measurements and calculations as well as a knowledge of reactor radiations and their interactions is necessary. Realizing the complexity and importance of this field, its development at widely separated laboratories and the need to bring the experts in this work together, the IAEA has convened three panel meetings. These were: 'In-pile dosimetry', held in July 1964 (published by the Agency as Technical Reports Series No. 46); 'Neutron fluence measurements', in October 1965; and 'In-pile dosimetry', in November 1966. The recommendations of these three panels led the Agency to form a Working Group on Reactor Radiation Measurements and to commission the writing of this book and a book on Neutron Fluence Measurements. The latter was published in May 1970 (Technical Reports Series No. 107). The material on neutron fluence and absorbed dose measurements is widely scattered in reports and reviews. It was considered that it was time for all relevant information to be evaluated and put together in the form of a practical guide that would be valuable both to experienced workers and beginners in the field

  3. Absorbed doses from intraoral radiography with special emphasis on collimator dimensions

    International Nuclear Information System (INIS)

    Stenstroem, B.; Henrikson, C.O.; Holm, B.; Richter, S.; Huddinge Univ. Hospital, Huddinge

    1986-01-01

    Thermoluminescence dosimeters were used in a phantom head and on patients to measure the absorbed dose to organs of special interest from full surveys with intraoral films (20 exposures) and single bitewing exposures. Two x-ray machines were used, operating at 65 kVp. The apertures of the circular tube collimators had diameters of 55 mm and 48 mm. Rectangular (35 mm x44 mm) tube collimators were also used. The distance from the x-ray focus to the open end of the collimators (FSD) was 0.20 and 0.35 m. Exposure values for Kodak Ultra-Speed film (speed group D) were used. The maximum skin dose measured from the full surveys decreased by 25 per cent on changing from the circular to the rectangular apertures. Using 0.35 m FSD and rectangular collimator the maximum skin dose was 13 mGy. The absorbed doses to the salivary glands and the thyroid gland were significantly reduced on changing from circular to rectangular apertures. The doses in the central part of the parotid and the thyroid glands were then 0.5 and 0.12 mGy, respectively, from a full survey with 20 intraoral films. With a leaded shield the thyroid dose was reduced to 0.05 mGy. All dose values could be further reduced by 40 per cent by using Kodak Ektaspeed film (speed group E)

  4. Current in-pile absorbed dose measurements at the Boris Kidric Institute of nuclear sciences - Vinca, Status report

    Energy Technology Data Exchange (ETDEWEB)

    Draganic, G I [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1966-11-15

    So far in-pile absorbed dose measurements have been limited only to experiments in the RA reactor at the Boris Kidric Institute of Nuclear Sciences at Vinca (6.5 D{sub 2}O moderated and 2% enriched uranium). The methods used for absorbed dose and neutron flux measurements were 1,2 discussed in some earlier reports at the IAEA meetings. The purpose of the present report is to illustrate the further development of methods of determining in-pile absorbed doses (author)

  5. Theoretic simulation for CMOS device on total dose radiation response

    International Nuclear Information System (INIS)

    He Baoping; Zhou Heqin; Guo Hongxia; He Chaohui; Zhou Hui; Luo Yinhong; Zhang Fengqi

    2006-01-01

    Total dose effect is simulated for C4007B, CC4007RH and CC4011 devices at different absorbed dose rate by using linear system theory. When irradiation response and dose are linear, total dose radiation and post-irradiation annealing at room temperature are determined for one random by choosing absorbed dose rate, and total dose effect at other absorbed dose rate can be predicted by using linear system theory. The simulating results agree with the experimental results at different absorbed dose rate. (authors)

  6. Evaluation of the absorbed dose in odontological computerized tomography; Avaliacao da dose absorvida em tomografia computadorizada odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, Adriano; Schelin, Hugo R; Rocha, Anna Silvia P.S. da, E-mail: schelin@utfpr.edu.b, E-mail: anna@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2011-10-26

    This paper evaluated the absorbed dose at the surface entry known as 'cone beam computed tomography' (CBCT) in odontological computerized tomography. Examination were simulated with CBCT for measurements of dose. A phantom were filled with water, becoming scatter object of radiation. Thermoluminescent dosemeters were positioned on points correspondent to eyes and salivary glands

  7. On the absorbed dose determination method in high energy photon beams

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Oane, M.; Mitru, E.; Avadanei, C.

    2008-01-01

    The absorbed dose determination method in water, based on standards of air kerma or exposure in high energy photon beams generated by electron with energies in the range of 1 MeV to 50 MeV is presented herein. The method is based on IAEA-398, AAPM TG-51, DIN 6800-2, IAEA-381, IAEA-277 and NACP-80 recommendations. The dosimetry equipment is composed of UNIDOS T 10005 electrometer and different ionization chambers calibrated in air kerma method in a Co 60 beam. Starting from the general formalism showed in IAEA-381, the determination of absorbed dose in water, under reference conditions in high energy photon beams, is given. This method was adopted for the secondary standard dosimetry laboratory (SSDL) in NILPRP-Bucharest

  8. Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method

    International Nuclear Information System (INIS)

    Norris, Edward T.; Liu, Xin; Hsieh, Jiang

    2015-01-01

    Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer

  9. Absorbed dose conversion coefficients for embryo and foetus in neutron fields

    International Nuclear Information System (INIS)

    Chen, J.

    2007-01-01

    The Monte Carlo code MCNPX has been used to determine mean absorbed doses to the embryo and foetus when the mother is exposed to neutron fields. There are situations, such as on-board aircraft, where high-energy neutrons are often peaked in top down (TOP) direction. In addition to previous publications for standard irradiation geometries, this study provides absorbed dose conversion coefficients for the embryo of 8 weeks and the foetus of 3, 6 or 9 months at TOP irradiation geometry. The conversion coefficients are compared with the coefficients in isotropic irradiation (ISO). With increasing neutron energies, the conversion coefficients in TOP irradiation become dominant. A set of conversion coefficients is constructed from the higher value in either ISO or TOP irradiation at a given neutron energy. In cases where the irradiation geometry is not adequately known, this set of conversion coefficients can be used in a conservative dose assessment for embryo and foetus in neutron fields. (authors)

  10. Evaluation of absorbed radiation dose in mammography using Monte Carlo simulation; Avaliacao da dose absorvida em mamografia usando simulacao Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruno L.; Tomal, Alessandra [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Fisica Gleb Wataghin

    2016-07-01

    Mammography is the main tool for breast cancer diagnosis, and it is based on the use of X-rays to obtain images. However, the glandular tissue present within the breast is highly sensitive to ionizing radiation, and therefore requires strict quality control in order to minimize the absorbed dose. The quantification of the absorbed dose in the breast tissue can be done by using Monte Carlo simulation, which allows a detailed study of the deposition of energy in different regions of the breast. Besides, the results obtained from the simulation can be associated with experimental data and provide values of dose interest, such as the dose deposited in glandular tissue. (author)

  11. The Norwegian system for implementing the IAEA code of practice based on absorbed dose to water

    International Nuclear Information System (INIS)

    Bjerke, H.

    2002-01-01

    The Norwegian Radiation Protection Authority (NRPA) SSDL recommended in 2000 the use of absorbed dose to water as the quality for calibration and code of practice in radiotherapy. The absorbed dose to water standard traceable to BIPM was established in Norway in 1995. The international code of practice, IAEA TRS 398 was under preparation. As a part of the implementation of the new dosimetry system the SSDL went to radiotherapy departments in Norway in 2001. The aim of the visit was to: Prepare and support the users in the implementation of TRS 398 by teaching, discussions and measurements on-site; Gain experience for NRPA in the practical implementation of TRS 398 and perform comparisons between TRS 277 and TRS 398 for different beam qualities; Report experience from implementation of TRS 398 to IAEA. The NRPA 30x30x30 cm 3 water phantom is equal to the BIPM calibration phantom. This was used for the photon measurements in 16 different beams. NRPA used three chambers: NE 2571, NE 2611 and PR06C for the photon measurements. As a quality control the set-up was compared with the Finnish site-visit equipment at University Hospital of Helsinki, and the measured absorbed dose to water agreed within 0.6%. The Finnish SSDL calibrated the Norwegian chambers and the absorbed dose to water calibration factors given by the two SSDLs for the three chambers agreed within 0.3%. The local clinical dosimetry in Norway was based on TRS 277. For the site-visit the absorbed dose to water was determined by NRPA using own equipment including the three chambers and the hospitals reference chamber. The hospital determined the dose the same evening using their local equipment. For the 16 photon beams the deviations between the two absorbed dose to water determinations for TRS 277 were in the range -1,7% to +4.0%. The uncertainty in the measurements was 1% (k=1). The deviation was explained in local implementation of TRS 277, the use of plastic phantoms, no resent calibration of

  12. In phantom calibration of a high dose rate remote afterloading device

    International Nuclear Information System (INIS)

    Alfonso, R.; Tolede, P.; Pich, V.

    1995-01-01

    The high dose-rate (HDR) brachytherapy in Cuba is based on soviet made devices type AGAT-V. In order to calibration one of these for clinical use a method based of the different measurement of absorbed dose at the reference point B in a paraffin phantom was developed. The results of the calibration are shown. From these results an analysis was made of the effective doses to prescription point a considering the Lineal-Quadratic model. The clinical results by using the AGAT-V device are displayed in a comparative way

  13. Evaluation of the absorbed dose in odontological computerized tomography; Avaliacao da dose absorvida em tomografia computadorizada odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, Adriano; Schelin, Hugo R.; Rocha, Anna Silvia P.S. da, E-mail: schelin@utfpr.edu.b, E-mail: anna@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2011-10-26

    This paper evaluated the absorbed dose at the surface entry known as 'cone beam computed tomography' (CBCT) in odontological computerized tomography. Examination were simulated with CBCT for measurements of dose. A phantom were filled with water, becoming scatter object of radiation. Thermoluminescent dosemeters were positioned on points correspondent to eyes and salivary glands

  14. Studies of the sensitivity dependence of float zone silicon diodes on gamma absorbed dose

    International Nuclear Information System (INIS)

    Pascoalino, K.C.S.; Santos, T.C. dos; Barbosa, R.F.; Camargo, F. de; Goncalves, J.A.C.; Bueno, C.C.

    2011-01-01

    Full text: Several advantages of silicon diodes which include small size, low cost, high sensitivity and wide availability, make them suitable for dosimetry and for radiation field mapping. However, the small radiation tolerance of ordinary silicon devices has imposed constraints on their application in intense radiation fields such as found in industrial radiation processes. This scenario has been changed with the development of radiation hard silicon devices to be used as track detectors in high-energy physics experiments. Particularly, in this work it is presented the dosimetric results obtained with a batch of nine junction silicon diodes developed, in the framework of CERN RD50 Collaboration, as good candidates for improved radiation hardness. These diodes were produced with 300 micrometer n-type silicon substrate grown by standard float zone technique and processed by the Microelectronics Center of Helsinki University of Technology. The samples irradiation was performed using a Co-60 irradiator (Gammacell 220) which delivers a dose-rate of 2 kGy/h. During the irradiation, the unbiased diodes were connected through low-noise coaxial cables to the input of a KEITHLEY 617 electrometer, in order to monitor the devices photocurrent as a function of the exposure time. To study the response uniformity of the batch of nine diodes as well the sensitivity dependence on the absorbed dose, they were irradiated with different doses from 5 kGy up to 50 kGy. The sensitivity response of each device was investigated through the on-line measurements of the current signals as a function of the exposure time. For doses up to 5 kGy, all diodes exhibited a current decay of almost six percent in comparison with the value registered at the start-time of the irradiation. However, this decrease in the current sensitivity is much smaller than those observed with ordinary diodes for the same absorbed dose. The dose-response curves of the devices were also investigated through the plot

  15. 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

  16. Study of absorbed dose distribution to high energy electron beams

    International Nuclear Information System (INIS)

    Cecatti, E.R.

    1983-01-01

    The depth absorbed dose distribution by electron beams was studied. The influence of the beam energy, the energy spread, field size and design characteristics of the accelerator was relieved. Three accelerators with different scattering and collimation systems were studied leading todifferent depth dose distributions. A theoretical model was constructed in order to explain the increase in the depth dose in the build-up region with the increase of the energy. The model utilizes a three-dimensional formalism based on the Fermi-Eyges multiple scattering theory, with the introduction of modifications that takes into account the criation of secondary electrons. (Author) [pt

  17. Determination of high level absorbed dose in a 60Co gamma ray field with ionization chambers

    International Nuclear Information System (INIS)

    Zhongying Li; Benjiang Mao; Lu Zhang

    1995-01-01

    This paper relates to the principles and methods for determining the absorbed dose of high energy photons radiation with ionization chambers, and its shows the doserate results of high level 60 Co γ-rays in water measured with Farmer chambers. The results with two kinds of chambers at a same point are consistent within 0.3%, and the total uncertainty is less than ± 4%. In the domestic intercomparison on determining high level absorbed dose in which 12 laboratories participated, the deviation of our result from the mean result of the intercomparison is -0.04% [Chen Yundong (1992). Summing up report on a high level absorbed dose intercomparison (in Chinese)]. (author)

  18. Absorbed doses received by infants subjected to panoramic dental and cephalic radiographs

    International Nuclear Information System (INIS)

    Carrizales, L.; Carreno, S.

    1998-01-01

    The IAEA Report No. 115 recommends that each country or region can establish levels of absorbed doses for each radiographic technique employed in diagnostic. assuming the extended and expensive of this purpose, we have been to begin in a first step with the dentistry area, in order to estimate the dose levels received at crystalline and thyroid level in infants that go to an important public institution in our country to realize panoramic and cephalic radiographs. This work will serve to justify and impel a quality assurance program in Venezuela on the dentistry area which includes aspects such as training for the medical lap referring the justification of the radiological practice, optimization of X-ray units to produce an adequate image quality that delivers to patient an absorbed dose as much lower as reasonably it can be reached without diagnostic detriment. (Author)

  19. Development of the 60Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water (ND,W)

    International Nuclear Information System (INIS)

    Fukumura, Akifumi; Mizuno, Hideyuki; Fukahori, Mai; Sakata, Suoh

    2013-01-01

    A primary standard for the absorbed dose rate to water in a 60 Co gamma-ray field was established at National Metrology Institute of Japan (NMIJ) in fiscal year 2011. Then, a 60 Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water was developed at National Institute of Radiological Sciences (NIRS) as a secondary standard dosimetry laboratory (SSDL). The results of an International Atomic Energy Agency (IAEA)/World Health Organization (WHO) TLD SSDL audit demonstrated that there was good agreement between NIRS stated absorbed dose to water and IAEA measurements. The IAEA guide based on the International Organization for Standardization (ISO) standard was used to estimate the relative expanded uncertainty of the calibration factor for a therapy-level Farmer type ionization chamber in terms of absorbed dose to water (N D,W ) with the new field. The uncertainty of N D,W was estimated to be 1.1% (k=2), which corresponds to approximately one third of the value determined in the existing air kerma field. The dissemination of traceability of the calibration factor determined in the new field is expected to diminish the uncertainty of dose delivered to patients significantly. (author)

  20. Proceedings of the workshop 'Absorbed dose in water and air'

    International Nuclear Information System (INIS)

    Rapp, Benjamin; Bordy, Jean-Marc; Camacho Caldeira, Margarida Isabela; Sochor, Vladimir; Celarel, Aurelia; Cenusa, Constentin; Cenusa, Ioan; Donois, Marc; Dusciac, Dorin; Iliescu, Elena; Ostrowsky, Aime; Bercea, Sorin; Blideanu, Valentin; Bordy, Jean-Marc; Steurer, Andrea; Tiefenboeck, Wilhelm

    2017-05-01

    The project 'Absorbed dose in water and air' (Absorb) is aimed at sharing and improving the knowledge on the design of Primary Standards (calorimeter, cavity ionization chambers, free air ionization chambers) for 'dose' measurements in radiation therapy and diagnostic, the harmonization of calibration procedures, the determination of uncertainty and harmonization of uncertainty budgets. Within the framework of this project a workshop was organized at the LNE (Laboratoire National de metrologie et d'Essais) in Paris from February, 29 to March, 2 2016. This report is the proceeding of this workshop. It includes a state of the art of two bilateral collaborations, launched to go beyond the framework of Absorb, between CEA LIST (LNE) LNHB and in one hand IFIN-HH (Romania), and in the other hand IST-LPSR-LMRI (Portugal) to build primary cavity ionization chambers for photons emitted by cobalt-60 and Cesium-137. Absorb is a Joint Research Project of the European Metrology Programme for Innovation and Research (EMPIR) which is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States

  1. Model of the contribution of the compton generated radiation to the dose rate for an experiment in a semi industrial irradiation plant

    International Nuclear Information System (INIS)

    Mangussi, Josefina

    2007-01-01

    The model of the build up contribution to the absorbed dose rate in a semi industrial irradiation plant is presented. A static irradiation of a lucite phantom with and without water is modeled. The absorbed dose was measured with silver and potassium dichromate dosemeters. Two approximations are used, the first one is a global adjustment of the attenuation coefficient and the second one consists in a detailed description of the Compton scattering. A specific numerical model is developed for each approximation and the absorbed dose rates calculated are compared with the experimental measurements. The achievements and limitations of both models are discussed. (author) [es

  2. Electron paramagnetic resonance measurements of absorbed dose in teeth from citizens of Ozyorsk

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, A.; Semiochkina, N. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, Neuherberg (Germany); Vasilenko, E.; Aladova, E.; Smetanin, M. [Southern Urals Biophysics Institute, Ozyorsk (Russian Federation); Fattibene, P. [Istituto Superiore di Sanita, Rome (Italy)

    2014-05-15

    In 1945, within the frame of the Uranium Project for the production of nuclear weapons, the Mayak nuclear facilities were constructed at the Lake Irtyash in the Southern Urals, Russia. The nuclear workers of the Mayak Production Association (MPA), who lived in the city of Ozyorsk, are the focus of epidemiological studies for the assessment of health risks due to protracted exposure to ionising radiation. Electron paramagnetic resonance measurements of absorbed dose in tooth enamel have already been used in the past, in an effort to validate occupational external doses that were evaluated in the Mayak Worker Dosimetry System. In the present study, 229 teeth of Ozyorsk citizens not employed at MPA were investigated for the assessment of external background exposure in Ozyorsk. The annually absorbed dose in tooth enamel from natural background radiation was estimated to be (0.7 ± 0.3) mGy. For citizens living in Ozyorsk during the time of routine noble gas releases of the MPA, which peaked in 1953, the average excess absorbed dose in enamel above natural background was (36 ± 29) mGy, which is consistent with the gamma dose obtained by model calculations. In addition, there were indications of possible accidental gaseous MPA releases that affected the population of Ozyorsk, during the early and late MPA operation periods, before 1951 and after 1960. (orig.)

  3. The METAS absorbed dose to water calibration service for high energy photon and electron beam radiotherapy

    International Nuclear Information System (INIS)

    Stucki, G.; Muench, W.; Quintel, H.

    2002-01-01

    Full text: The Swiss Federal Office of Metrology and Accreditation (METAS) provides an absorbed dose to water calibration service for reference dosimeters using 60 Co γ radiation, ten X-ray beam qualities between TPR 20,10 =0.639 and 0.802 and ten electron beam qualities between R 50 =1.75 gcm -2 and 8.54 gcm -2 . A 22 MeV microtron accelerator with a conventional treatment head is used as radiation source for the high energy photon and electron beams. The treatment head produces clinical beams. The METAS absorbed dose calibration service for high energy photons is based on a primary standard sealed water calorimeter of the Domen type, that is used to calibrate several METAS transfer standards of type NE2611A and NE2571A in terms of absorbed dose to water in the energy range from 60 Co to TPR 20,10 = 0.802. User reference dosimeters are compared with the transfer standards to give calibration factors in absorbed dose to water with an uncertainty of 1.0% for 60 Co γ radiation and 1.4% for higher energies (coverage factor k=2). The calibration service was launched in 1997. The calibration factors measured by METAS have been compared with those derived from the Code of Practice of the International Atomic Energy Agency using the calculated k Q factors listed in table 14. The comparison showed a maximum difference of 0.8% for the NE25611A and NE 2571A chambers. At 60 Co γ radiation the METAS primary standard of absorbed dose to water was bilaterally compared with the primary standards of the Bureau International des Poids et Mesures BIPM (Sevres) as well as of the National Research Council NRC (Canada). In either case the standards were in agreement within the comparison uncertainties. The METAS absorbed dose calibration service for high energy electron beams is based on a primary standard chemical dosimeter. A monoenergetic electron beam of precisely known particle energy and beam charge is totally absorbed in Fricke solution (ferrous ammonium sulphate) of a given

  4. Estimation of absorbed doses in humans due to intravenous administration of fluorine-18-fluorodeoxyglucose in PET studies

    International Nuclear Information System (INIS)

    Mejia, A.A.; Nakamura, T.; Masatoshi, I.; Hatazawa, J.; Masaki, M.; Watanuki, S.

    1991-01-01

    Radiation absorbed doses due to intravenous administration of fluorine-18-fluorodeoxyglucose in positron emission tomography (PET) studies were estimated in normal volunteers. The time-activity curves were obtained for seven human organs (brain, heart, kidney, liver, lung, pancreas, and spleen) by using dynamic PET scans and for bladder content by using a single detector. These time-activity curves were used for the calculation of the cumulative activity in these organs. Absorbed doses were calculated by the MIRD method using the absorbed dose per unit of cumulated activity, 'S' value, transformed for the Japanese physique and the organ masses of the Japanese reference man. The bladder wall and the heart were the organs receiving higher doses of 1.2 x 10(-1) and 4.5 x 10(-2) mGy/MBq, respectively. The brain received a dose of 2.9 x 10(-2) mGy/MBq, and other organs received doses between 1.0 x 10(-2) and 3.0 x 10(-2) mGy/MBq. The effective dose equivalent was estimated to be 2.4 x 10(-2) mSv/MBq. These results were comparable to values of absorbed doses reported by other authors on the radiation dosimetry of this radiopharmaceutical

  5. Calculation of absorbed dose in water by chemical Fricke dosimetry

    International Nuclear Information System (INIS)

    Rodrigues, Adenilson Paiva; Meireles, Ramiro Conceicao

    2016-01-01

    This work is the result of a laboratory activity performed in Radiological Sciences Laboratory (CRL), linked to the State University of Rio de Janeiro (UERJ). This practice aimed to determine the absorbed dose to water, through the primary calibration method called dosimetry Fricke, which consists of ferrous ions (Fe + 2) to ferric (Fe + 3), generated by water radiolysis products which is the structural change of water molecule caused by ionizing radiation. A spectrophotometer was used to extract data for analysis at a wavelength (λ) 304 and 224 nm with function of measuring the absorbance using bottles with irradiated and nonirradiated Fricke solution. (author)

  6. International comparison of calibration standards for exposure and absorbed dose

    International Nuclear Information System (INIS)

    Horakova, I.; Wagner, R.

    1990-01-01

    A comparison was performed of the primary calibration standards for 60 Co gamma radiation dose from Czechoslovakia (UDZ CSAV, Prague), Austria (OEFZS/BEV Seibersdorf) and Hungary (OMH Budapest) using ND 1005 (absolute measurement) and V-415 (by means of N x ) graphite ionization chambers. BEV achieved agreement better than 0.1%, OMH 0.35%. Good agreement was also achieved for the values of exposure obtained in absolute values and those obtained via N x , this for the ND 1005/8105 chamber. The first ever international comparison involving Czechoslovakia was also performed of the unit of absorbed gamma radiation in a water and/or graphite phantom. The participants included Czechoslovakia (UDZ CSAV Prague), the USSR (VNIIFTRI Moscow) and Austria (OEFZS/BEV Seibersdorf). In all measurements, the agreement was better than 1%, which, in view of the differences in methodologies (VNIIFTRI, BEV: calorimetry, UDZ, UVVVR: ionometry) and the overall inaccuracies in determining the absorbed dose values, is a good result. (author)

  7. Consequences of the exposure at low dose rates-contribution of animal experimentation

    International Nuclear Information System (INIS)

    Masse, R.

    1990-01-01

    The exposure of laboratory animals to the various types of radiations will induce cancers in relation with the tissue absorbed doses. The shape of the dose-effet relationship is most variable. It is important to distinguish which tumours are comparable to human tumours. Those showing more analogies answer but seldom to the classical lineo-quadratic relationship; however, a strong attenuation of induction is demonstrated at low dose rates. Quasi-threshold relationships are seen after the exposure of some tissues to high-LET radiations. These observations question the validity of generalizing the radiobiologists' dual action theory, setting the origin of the dose-effect relationship in the induction of events within the DNA molecule. There is an alternative in the cellular collaboration events; it assumes that the effectiveness per dose unit decreases constantly as an inverse function of the dose rate [fr

  8. Evaluation of the distribution of absorbed dose in child phantoms exposed to diagnostic medical x rays

    International Nuclear Information System (INIS)

    Chen, W.L.

    1977-01-01

    The purpose of the study was to determine, by theoretical calculation and experimental measurement, the absorbed dose distributions in two heterogeneous phantoms representing one-year- and five-year-old children from typical radiographic examinations for those ages. Theoretical work included the modification of an existing internal dose code which used Monte Carlo methods to determine doses within the Snyder-Fisher mathematical phantom. A Ge(Li) detector and a pinhole collimator were used to measure x-ray spectra which served as input (i.e., the source routine) to the modified Monte Carlo codes which were used to calculate organ doses in children. Experimental work included the fabrication of child phantoms to match the existing mathematical models. These phantoms were constructed of molded lucite shells filled with differing materials to simulate lung, skeletal, and soft-tissue regions. The skeleton regions of phantoms offered the opportunity to perform meaningful measurements of absorbed dose to bone marrow and bone. Thirteen to fourteen sites in various bones of the skeleton were chosen for placement of TLDs. These sites represented important regions in which active bone marrow is located. Sixteen typical radiographic examinations were performed representing common pediatric diagnostic procedures. The calculated and measured tissue-air values were compared for a number of organs. For most organs, the results of the calculated absorbed doses agreed with the measured absorbed doses within twice the coefficient of variation of the calculated value. The absorbed dose to specific organs for several selected radiological examinations are given for one-year-old, five-year-old, and adult phantoms. For selected radiological exposures, the risk factors of leukemia, thyroid cancer, and genetic death are estimated for one-year- and five-year-old children

  9. Variations in absorbed doses from 59Fe in different diseases

    International Nuclear Information System (INIS)

    Roth, P.; Werner, E.; Henrichs, K.; Elsasser, U.; Kaul, A.

    1986-01-01

    The biokinetics of radiopharmaceuticals administered in vivo may vary considerably with changes in organ functions. They studied the variations in absorbed doses from 59 Fe in 207 patients with different diseases, in whom ferrokinetic investigations were performed for diagnostic purposes. Radiation doses to the bone marrow were highest in patients with deserythropoietic anemias (mean 38 nSv/Bq, range 19 - 57 nSv/Bq) and in hemolytic anemias (mean 21 nSv/Bq, range 7 - 35 nSv/Bq), whereas lower and rather constant values were found in other diseases (mean values between 9 and 13 nSv/Bq). The highest organ doses, the greatest differences with respect to diagnosis and also the largest variations within each group of patients were found for liver and spleen (e. g. in aplastic anemia; liver: 66 nSv/Bq, range 29 - 104 nSv/Bq; spleen: 57 nSv/Bq, range 34 - 98 nSv/Bq. In iron deficiency; liver: 13 nSv/Bq range 12 - 14 nSv/q; spleen: 19 nSv/Bq, range 18 - 20 nSv/Bq). Lower organ doses and smaller variations within and between the groups of patients were found for the gonads (means 3 - 7 nSv/Bq), the kidneys (means 10 - 13 nSv/Bq), the bone (means 4 - 7 nSv/Bq), the lung (means 8 - 12 nSv/Bq), and the total body (means 6 - 8 nSv/Bq). In patients with chronic bleeding absorbed doses decrease concomitantly to the extent of blood loss. The D/sub E/ is not markedly affected by the variations in organ doses but is fairly constant for different diseases. 16 references, 1 figure, 3 tables

  10. Measurement of absorbed radiation doses during whole body irradiation for bone marrow transplants using thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Giordani, Adelmo Jose; Segreto, Helena Cristina Comodo; Segreto, Roberto Araujo; Medeiros, Regina Bitelli; Oliveira, Jose Salvador R. de

    2004-01-01

    The objective was to evaluate the precision of the absorbed radiation doses in bone marrow transplant therapy during whole body irradiation. Two-hundred CaSO 4 :Dy + teflon tablets were calibrated in air and in 'phantom'. These tablets were randomly selected and divided in groups of five in the patients' body. The dosimetric readings were obtained using a Harshaw 4000A reader. Nine patients had their entire bodies irradiated in parallel and opposite laterals in a cobalt-60 Alcion II model, with a dose rate of 0.80 Gy/min at 80.5 cm, {(10 ? 10) cm 2 field. The dosimetry of this unit was performed using a Victoreen 500 dosimeter. For the determination of the mean dose at each point evaluated, the individual values of the tablets calibrated in air or 'phantom' were used, resulting in a build up of 2 mm to superficialize the dose at a distance of 300 cm. In 70% of the patients a variation of less than 5% in the dose was obtained. In 30% of the patients this variation was less than 10%, when values obtained were compared to the values calculated at each point. A mean absorption of 14% was seen in the head, and an increase of 2% of the administered dose was seen in the lungs. In patients with latero-lateral distance greater than 35 cm the variation between the calculated doses and the measured doses reached 30% of the desired dose, without the use of compensation filters. The measured values of the absorbed doses at the various anatomic points compared to the desired doses (theoretic) presented a tolerance of ± 10%, considering the existent anatomical differences and when using the individual calibration factors of the tablets. (author)

  11. Three-dimensional determination of absorbed dose by spectrophotometric analysis of ferrous-sulphate agarose gel

    International Nuclear Information System (INIS)

    Gambarini, G.; Gomarasca, G.; Marchesini, R.; Pecci, A.; Pirola, L.; Tomatis, S.

    1999-01-01

    We describe a technique to obtain three-dimensional (3-D) imaging of an absorbed dose by optical transmittance measurements of phantoms composed by agarose gel in which a ferrous sulphate and xylenol orange solution are incorporated. The analysis of gel samples is performed by acquiring transmittance images with a system based on a CCD camera provided with an interference filter matching the optical absorption peak of interest. The proposed technique for 3-D measurements of an absorbed dose is based on the imaging of phantoms composed of sets of properly piled up gel slices. The slice thickness was optimized in order to obtain a good image contrast as well as a good in-depth spatial resolution. To test the technique, a phantom has been irradiated with a collimated γ-beam and then analysed. Proper software was adapted in order to visualise the images of all slices and to attain the 2-D profiles of the dose absorbed by each slice

  12. Calculations radiobiological using the quadratic lineal model in the use of the medium dose rate absorbed in brachytherapy. Pt. 3

    International Nuclear Information System (INIS)

    2002-01-01

    Calculations with the quadratic lineal model for medium rate using the equation dose-effect. Several calculations for system of low dose rate brachytherapy plus teletherapy, calculations for brachytherapy with medium dose rate together with teletherapy, dose for fraction and the one numbers of fractions in medium rate

  13. Standard Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This guide describes different mathematical methods that may be used to calculate absorbed dose and criteria for their selection. Absorbed-dose calculations can determine the effectiveness of the radiation process, estimate the absorbed-dose distribution in product, or supplement or complement, or both, the measurement of absorbed dose. 1.2 Radiation processing is an evolving field and annotated examples are provided in Annex A6 to illustrate the applications where mathematical methods have been successfully applied. While not limited by the applications cited in these examples, applications specific to neutron transport, radiation therapy and shielding design are not addressed in this document. 1.3 This guide covers the calculation of radiation transport of electrons and photons with energies up to 25 MeV. 1.4 The mathematical methods described include Monte Carlo, point kernel, discrete ordinate, semi-empirical and empirical methods. 1.5 General purpose software packages are available for the calcul...

  14. Field measurement and interpretation of beta doses and dose rates

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

    1983-01-01

    A large number of portable survey instruments employing G.M., ionization chamber, and scintillation detectors used for gamma measurements are also used for monitoring in beta fields by using removable shields to separate the beta and gamma components of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. Appropriate calibrations and correction factors can be used to reduce the errors in beta measurements to a tolerable level

  15. Aspects of pre-dose and other luminescence phenomena in quartz absorbed dose estimation

    International Nuclear Information System (INIS)

    Adamiec, G.

    2000-01-01

    The understanding of all luminescence processes occurring in quartz is of paramount importance in the further development of robust absorbed dose estimation techniques (for the purpose of dating and retrospective dosimetry). The findings presented in this thesis, aid future improvements of absorbed dose estimation techniques using quartz by presenting investigations in the following areas: 1) interpretation of measurement results, 2) numerical modelling of luminescence in quartz, 3) phenomena needing inclusion in future physical models of luminescence. In the first part, the variability of properties of single quartz grains is examined. Through empirical and theoretical considerations, investigations are made of various problems of measurements of luminescence using multi-grain aliquots, and specifically areas where the heterogeneity of the sample at the inter-grain level may be misinterpreted at the multi-grain-aliquot level. The results obtained suggest that the heterogeneity of samples is often overlooked, and that such differences can have a profound influence on the interpretation of measurement results. Discussed are the shape of TL glow curves, OSL decay curves, dose response curves (including consequences for using certain signals as proxies for others), normalisation procedures and D E estimation techniques. Further, a numerical model of luminescence is proposed, which includes multiple R-centres and is used to describe the pre-dose sensitisation in quartz. The numerical model exhibits a broad-scale behaviour observed experimentally in a sample of annealed quartz. The shapes of TAC for lower (20 Gy) and higher doses (1 kGy) and the evolution with temperature of the isothermal sensitisation curves are qualitatively matched for the empirical and numerical systems. In the third area, a preliminary investigation of the properties of the '110 deg. C peak' in the 550 nm emission band, in annealed quartz is presented. These properties are in sharp contrast with

  16. Radiation absorbed doses at radiographic examination of third molars

    International Nuclear Information System (INIS)

    Rehnmark-Larsson, S.; Stenstroem, B.; Julin, P.; Richter, S.; Huddinge University Hospital

    1981-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. The greatest thyroid dose, 35 μGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. the corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50 %. The Ekta-Speed film requirted approximately 40 % lower exposure than the Ultra-Speed film. A horizontal radiation shield reduced the thyroid doses by between 12 and 46 % and the gonadal doses by between 50 and 95 %. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses between 15 and 42 % and the gonadal doses by two orders of magnitude. (Authors)

  17. Spatial accuracy of 3D reconstructed radioluminographs of serial tissue sections and resultant absorbed dose estimates

    Energy Technology Data Exchange (ETDEWEB)

    Petrie, I.A.; Flynn, A.A.; Pedley, R.B.; Green, A.J.; El-Emir, E.; Dearling, J.L.J.; Boxer, G.M.; Boden, R.; Begent, R.H.J. [Cancer Research UK Targeting and Imaging Group, Department of Oncology, Royal Free and University College Medical School, Royal Free Campus, London (United Kingdom)

    2002-10-21

    Many agents using tumour-associated characteristics are deposited heterogeneously within tumour tissue. Consequently, tumour heterogeneity should be addressed when obtaining information on tumour biology or relating absorbed radiation dose to biological effect. We present a technique that enables radioluminographs of serial tumour sections to be reconstructed using automated computerized techniques, resulting in a three-dimensional map of the dose-rate distribution of a radiolabelled antibody. The purpose of this study is to assess the reconstruction accuracy. Furthermore, we estimate the potential error resulting from registration misalignment, for a range of beta-emitting radionuclides. We compare the actual dose-rate distribution with that obtained from the same activity distribution but with manually defined translational and rotational shifts. As expected, the error produced with the short-range {sup 14}C is much larger than that for the longer range {sup 90}Y; similarly values for the medium range {sup 131}I are between the two. Thus, the impact of registration inaccuracies is greater for short-range sources. (author)

  18. The calculation of absorbed dose rate in freshwater fish from high background natural radioactivity areas

    International Nuclear Information System (INIS)

    Pereira, W.S.; Moraes, S.R.; Cavalcante, J.J.V.; Pinto, C.E.C.; Kelecom, A.

    2017-01-01

    Areas of increased radiation may expose biota to radiation doses greater than the world averages, and depending on the magnitude of the exposure causing biota damage. The region of the municipality of Caldas, MG, BR is considered a region of increased natural radioactivity. The present work aims to evaluate the exposure of biota to natural radionuclides in the region of Caldas, MG. In order to evaluate the biota exposure in the region, the concentrations of the natural radionuclides U nat , 226 Ra, 210 Pb and 232 Th and 228 Ra were evaluated in two species of fishes: lambari (Astymax spp.) And traíra (Hoplias spp.). The dose rates of the analyzed fish were: for Astymax spp of 0.08 μGy d -1 and for Hoplias spp of 0.12 μGy∙d -1 . With these dose rate values no measurable deleterious effects are expected in the species studied

  19. 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.

  20. Modeling for Dose Rate Calculation of the External Exposure to Gamma Emitters in Soil

    International Nuclear Information System (INIS)

    Allam, K. A.; El-Mongy, S. A.; El-Tahawy, M. S.; Mohsen, M. A.

    2004-01-01

    Based on the model proposed and developed in Ph.D thesis of the first author of this work, the dose rate conversion factors (absorbed dose rate in air per specific activity of soil in nGy.hr - 1 per Bq.kg - 1) are calculated 1 m above the ground for photon emitters of natural radionuclides uniformly distributed in the soil. This new and simple dose rate calculation software was used for calculation of the dose rate in air 1 m above the ground. Then the results were compared with those obtained by five different groups. Although the developed model is extremely simple, the obtained results of calculations, based on this model, show excellent agreement with those obtained by the above-mentioned models specially that one adopted by UNSCEAR. (authors)

  1. Estimation of the total absorbed dose by quartz in retrospective conditions

    International Nuclear Information System (INIS)

    Correcher, V.; Delgado, A.

    2003-01-01

    The estimation of the total absorbed dose is of great interest in areas affected by a radiological accident when no conventional dosimetric systems are available. This paper reports about the usual methodology employed in dose reconstruction from the thermoluminescence (TL) properties of natural quartz, extracted from selected ceramic materials (12 bricks) picked up in the Chernobyl area. It has been possible to evaluate doses under 50mGy after more than 11 years later since the radiological accident happened. The main advance of this fact is the reduction of the commonly accepted limit dose estimation more than 20 times employing luminescence methods. (Author) 11 refs

  2. Calorimeter measurements of absorbed doses at the heavy water enriched uranium reactor

    International Nuclear Information System (INIS)

    Markovic, V.

    1961-12-01

    Application of calorimetry measurements of absorbed doses was imposed by the need of good knowledge of the absorbed dose values in the reactor experimental channels. Other methods are considered less reliable. The work was done in two phases: calorimetry measurements at lower reactor power (13-80 kW) by isothermal calorimeter, and differential calorimeter constructions for measurements at higher power levels (up to 1 MW). This report includes the following four annexes, papers: Isothermal calorimeter for reactor radiation monitoring, to be published; Calorimeter dosimetry of reactor radiation, presented at the Symposium about nuclear fuel held in april 1961; Radiation dosimetry of the reactor RA at Vinca, published in the Bull. Inst. Nucl. Sci. 1961; Differential calorimeter for reactor radiation dosimetry

  3. Evaluation of surface dose rate on C-14 scrubber and gas bag

    International Nuclear Information System (INIS)

    Gang, D. W.; Lee, H. S.; Lee, D. H.

    2003-01-01

    In CANDU(Canadian Deuterium Uranium) reactors, purge and discharge of moderator cover gas has been performed via vapor recovery system. The methods employed in C-14 removal are mainly based on reactions of CO 2 with absorber of adsorbent. In order to choose an optimum process, we should consider the characteristics of the process, such as, temperature, pressure, humidity etc. and surface dose rate on C-14 scrubber and gas bag to estimate job-related personnel doses. Assuming that the whole C-14 scrubber was completely replaced after one-cycle operation, and that its C-14 activity for one-cycle operation was 40 mCi, we calculated the surface dose rate at the six points of the C-14 scrubber. This calculation showed that the dose rate on the surface of cartridge was only 1.25μSυ/hγ because of low energy of β ray. It is concluded, therefore, that the cartridge change-out is safe because the operation of C-14 removal system causes only a small increase in dose rate

  4. Model of the absorbed dose on a small sphere into a gamma irradiation field

    International Nuclear Information System (INIS)

    Mangussi, J.

    2009-01-01

    Several models of the absorbed dose calculated as the energy deposited by the secondary electrons on a small volume sphere are presented. The calculations use the Compton scattering of a uniform photon beam in water, the photon attenuation and the electron stopping power are included. The sphere total absorbed dose is due to the stopping of the electrons generated in three regions: into the sphere volume, ahead and behind the sphere volume. Calculations are performed for spheres of different radius and placed at various depth of the vacuum - water interface. (author)

  5. Total skin high-dose-rate electron therapy dosimetry using TG-51

    International Nuclear Information System (INIS)

    Gossman, Michael S.; Sharma, Subhash C.

    2004-01-01

    An approach to dosimetry for total skin electron therapy (TSET) is discussed using the currently accepted TG-51 high-energy calibration protocol. The methodology incorporates water phantom data for absolute calibration and plastic phantom data for efficient reference dosimetry. The scheme is simplified to include the high-dose-rate mode conversion and provides support for its use, as it becomes more available on newer linear accelerators. Using a 6-field, modified Stanford technique, one may follow the process for accurate determination of absorbed dose

  6. Towards a determination of the absorbed dose to water in water for low-energy photon-emitting brachytherapy seeds

    International Nuclear Information System (INIS)

    Schneider, T.; Lange, B.; Selbach, H.J.

    2007-01-01

    An accurate determination of the dose produced by brachytherapy seeds emitting low-energy photons is an important component of the radiotherapeutic process. As yet, the output of these seeds has usually been specified in terms of the air kerma rate. The desired quantity in radiation therapy is, however, the absorbed dose to water inside a water phantom, for which primary standards are not available. For this reason, developments are under way in the Physikalisch - Technische Bundesanstalt to establish a primary standard to determine the absorbed dose to water within a phantom. As a fundamental step towards this aim, a method will be introduced in this publication to determine the water kerma inside a graphite phantom housing an extrapolation chamber. Experimental results will be presented and compared with water kerma values obtained from air kerma measurements in free air and applying a conversion factor to water kerma for the conditions of the experiment. First estimates indicate that the relative uncertainty is of the order of 1% (k 1). (authors)

  7. OEDIPE, a software for personalized Monte Carlo dosimetry and treatment planning optimization in nuclear medicine: absorbed dose and biologically effective dose considerations

    International Nuclear Information System (INIS)

    Petitguillaume, A.; Broggio, D.; Franck, D.; Desbree, A.; Bernardini, M.; Labriolle Vaylet, C. de

    2014-01-01

    For targeted radionuclide therapies, treatment planning usually consists of the administration of standard activities without accounting for the patient-specific activity distribution, pharmacokinetics and dosimetry to organs at risk. The OEDIPE software is a user-friendly interface which has an automation level suitable for performing personalized Monte Carlo 3D dosimetry for diagnostic and therapeutic radionuclide administrations. Mean absorbed doses to regions of interest (ROIs), isodose curves superimposed on a personalized anatomical model of the patient and dose-volume histograms can be extracted from the absorbed dose 3D distribution. Moreover, to account for the differences in radiosensitivity between tumoral and healthy tissues, additional functionalities have been implemented to calculate the 3D distribution of the biologically effective dose (BED), mean BEDs to ROIs, isoBED curves and BED-volume histograms along with the Equivalent Uniform Biologically Effective Dose (EUD) to ROIs. Finally, optimization tools are available for treatment planning optimization using either the absorbed dose or BED distributions. These tools enable one to calculate the maximal injectable activity which meets tolerance criteria to organs at risk for a chosen fractionation protocol. This paper describes the functionalities available in the latest version of the OEDIPE software to perform personalized Monte Carlo dosimetry and treatment planning optimization in targeted radionuclide therapies. (authors)

  8. Monte Carlo estimation of the absorbed dose in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Woo; Youn, Han Bean; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

    2016-05-15

    The purpose of this study is to devise an algorithm calculating absorbed dose distributions of patients based on Monte Carlo (MC) methods, and which includes the dose estimations due to primary and secondary (scattered) x-ray photons. Assessment of patient dose in computed tomography (CT) at the population level has become a subject of public attention and concern, and ultimate CT quality assurance and dose optimization have the goal of reducing radiation-induced cancer risks in the examined population. However, the conventional CT dose index (CTDI) concept is not a surrogate of risk but it has rather been designed to measure an average central dose. In addition, the CTDI or the dose-length product has showed troubles for helical CT with a wider beam collimation. Simple algorithms to estimate a patient specific CT dose based on the MCNP output data have been introduced. For numerical chest and head phantoms, the spatial dose distributions were calculated. The results were reasonable. The estimated dose distribution map can be readily converted into the effective dose. The important list for further studies includes the validation of the models with the experimental measurements and the acceleration of algorithms.

  9. Extension of the Commonwealth standard of absorbed dose from cobalt-60 energy to 25 MV

    International Nuclear Information System (INIS)

    Sherlock, S.L.

    1986-01-01

    With the introduction of high energy linear accelerators in hospitals, there is a need for direct measurement of absorbed dose for energies to 25 MV for photons and 20 MeV electrons. The present Australian standard for absorbed dose at cobalt-60 energy is a graphite micro-calorimeter maintained at the AAEC Lucas Heights Research Laboratories. A thorough theoretical analysis of calorimeter operation suggests that computer control and monitoring techniques are appropriate. Solution of Newton's law of cooling for a four-body calorimeter allows development of a computer simulation model. Different temperature control algorithms may then be run and assessed using this model. In particular, the application of a simple differencer is examined. Successful implementation of the calorimeter for energies up to 25 MV could lead to the introduction of an Australian absorbed dose protocol based on calorimetry, therby reducing the uncertainties associated with exposure-based protocols

  10. Fetus absorbed dose evaluation in head and neck radiotherapy procedures of pregnant patients

    International Nuclear Information System (INIS)

    Camargo da C, E.; Ribeiro da R, L. A.; Santos B, D. V.

    2014-08-01

    Each year a considerable amount of pregnant women needs to be submitted to radiotherapeutic procedures to combat malignant tumors. Radiation therapy is often a treatment of choice for these patients. It is possible to use shielding and beam positioning such that the potential dose to the fetus can be minimized. In this work the head and neck cancer treatment of a pregnant patient was experimentally simulated. The patient was simulated by an anthropomorphic Alderson phantom and the absorbed dose to the fetus was evaluated using micro-rod TLD-100 detectors in two conditions, namely protecting the patients abdomen with a 7 cm lead layer and using no abdomen shielding. The aim of this experiment was to evaluate the efficiency of the abdomen protection in reducing the fetus absorbed dose. Irradiations were performed with a Trilogy linear accelerator using x-rays of 6 MV. A total dose of 50 Gy to the target volume was delivered. The fetus doses evaluated with and without the lead shielding were, respectively, 0.52±0.039 and (0.88±0.052) c Gy, corresponding to a dose reduction of 59%. The dose (0.52±0.039) c Gy is within the zone of biological tolerance for the fetus. (Author)

  11. Fetus absorbed dose evaluation in head and neck radiotherapy procedures of pregnant patients

    Energy Technology Data Exchange (ETDEWEB)

    Camargo da C, E.; Ribeiro da R, L. A.; Santos B, D. V., E-mail: etieli@ird.gov.br [Instituto de Radioprotecao e Dosimetria / CNEN, Av. Salvador Allende s/n, Barra de Tijuca, 22783-127 Rio de Janeiro (Brazil)

    2014-08-15

    Each year a considerable amount of pregnant women needs to be submitted to radiotherapeutic procedures to combat malignant tumors. Radiation therapy is often a treatment of choice for these patients. It is possible to use shielding and beam positioning such that the potential dose to the fetus can be minimized. In this work the head and neck cancer treatment of a pregnant patient was experimentally simulated. The patient was simulated by an anthropomorphic Alderson phantom and the absorbed dose to the fetus was evaluated using micro-rod TLD-100 detectors in two conditions, namely protecting the patients abdomen with a 7 cm lead layer and using no abdomen shielding. The aim of this experiment was to evaluate the efficiency of the abdomen protection in reducing the fetus absorbed dose. Irradiations were performed with a Trilogy linear accelerator using x-rays of 6 MV. A total dose of 50 Gy to the target volume was delivered. The fetus doses evaluated with and without the lead shielding were, respectively, 0.52±0.039 and (0.88±0.052) c Gy, corresponding to a dose reduction of 59%. The dose (0.52±0.039) c Gy is within the zone of biological tolerance for the fetus. (Author)

  12. Robotic stereotactic radioablation of breast tumors: Influence of beam size on the absorbed dose distributions

    International Nuclear Information System (INIS)

    Garnica-Garza, H.M.

    2016-01-01

    Robotic stereotactic radioablation (RSR) therapy for breast tumors has been shown to be an effective treatment strategy when applied concomitantly with chemotherapy, with the purpose of reducing the tumor volume thus making it more amenable for breast conserving surgery. In this paper we used Monte Carlo simulation within a realistic patient model to determine the influence that the variation in beam collimation radius has on the resultant absorbed dose distributions for this type of treatment. Separate optimized plans were obtained for treatments using 300 circular beams with radii of 0.5 cm, 0.75 cm, 1.0 cm and 1.5 cm. Cumulative dose volume histograms were obtained for the gross, clinical and planning target volumes as well as for eight organs and structures at risk. Target coverage improves as the collimator size is increased, at the expense of increasing the volume of healthy tissue receiving mid-level absorbed doses. Interestingly, it is found that the maximum dose imparted to the skin is highly dependent on collimator size, while the dosimetry of other structures, such as both the ipsilateral and contralateral lung tissue are basically unaffected by a change in beam size. - Highlights: • Stereotactic body radiation therapy of breast tumors is analyzed using Monte Carlo simulation. • The influence of beam collimation on the absorbed dose distributions is determined. • Large field sizes increase target dose uniformity and midlevel doses to healthy structures. • Skin dose is greatly affected by changes in beam collimation.

  13. Field measurement and interpretation of beta doses and dose rates

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

    1983-01-01

    A wide variety of portable survey instruments employing GM, ionization chamber and scintillation detectors exist for the measurement of gamma exposure rates. Often these same survey instruments are used for monitoring beta fields. This is done by making measurements with and without a removable shield which is intended to shield out the non-penetrating component (beta) of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. In many instances correction factors have been derived, that if properly applied, can reduce these errors substantially. However, this requires some knowledge of the beta spectra, calibration techniques and source geometry. This paper discusses some aspects of the proper use of instruments for beta measurements including the application of appropriate correction factors. Ionization type instruments are commonly used to measure beta dose rates. Through design and calibration these instruments will give an accurate reading only for uniform irradiation of the detection volume. Often in the field it is not feasible to meet these conditions. Large area uniform distributions of activity are not generally encountered and it is not possible to use large source-to-detector distances due to beta particle absorption in air. An example of correction factors required for various point sources is presented when a cutie pie ionization chamber is employed. The instrument reading is multiplied by the appropriate correction factor to obtain the dose rate at the window. When a different detector is used or for other geometries, a different set of correction factors must be used

  14. Status of radiation dosimetry in Germany using ionization chamber calibrated in terms of absorbed dose to water

    International Nuclear Information System (INIS)

    Hohlfeld, Klaus; Roos, Martin

    1995-01-01

    In 1984 the PTB as PSDL and the DIN Standard Committee on Radiology (NAR) in close co-operation decided that in Germany the measured absorbed dose to water in a water phantom should replace exposure in the dosimetry for radiation therapy. The PTB has established primary standards of water absorbed dose in the whole range of photon and electron radiation, and international comparisons at the BIPM and with other PSDLs proved agreement within 0.5%. Secondary standards are calibrated in a water phantom under reference conditions in a Co-60 gamma radiation beam at the PTB. Thus, the calibration factor in terms of water absorbed dose, N W , is transferred to the manufacturers of dosimeters, the German Calibration Service and the dosimetry laboratories of the verification authorities. The Verification Law subjects each ionization dosimeter used in the treatment of patients with external photon radiation beams under a type-test at PTB and under a verification procedure, where the calibration factor, N W , must be shown to be within given limits. The absorbed dose determination at the users' level follows the foralism prescribed in the Standard DIN 6800-2 (1995) 'Procedures for Absorbed Dose Determination in Radiology by the Ionization Method'. The concept of this DIN Standard uses exclusively one quantity from the primary standard to the user's instrument eliminating uncertainties and sources of mistakes associated with the conversion of a calibration factor. The concept is simple and clear and covers the whole range of photon and electron radiation. As a means of quality assurance in basic dosimetry the PTB runs a calibration service, up to now on a voluntary basis, which allows the user to compare his dosimetry system against PTB standards using mailed Fricke ampoules, with water absorbed dose as measured and used

  15. Fishes of water bodies within the Ukrainian part of the Chernobyl exclusion zone: current levels of radioactive contamination and absorbed dose rate

    Energy Technology Data Exchange (ETDEWEB)

    Kaglyan, Alexander Ye.; Gudkov, Dmitri I. [Institute of Hydrobiology of the NAS of Ukraine, Geroyiv Stalingrada Ave. 12, UA- 04210, Kyiv (Ukraine)

    2014-07-01

    The results of studies of radioactive contamination of ichthyofauna of water bodies of the Chernobyl exclusion zone (ChEZ) during 2012-2013 are presented. The fish sampled from water bodies with different hydrological mode was used: (1) stagnant lakes (Vershyna, Glyboke, Azbuchyn, Daleke); (2) reservoir with slow water exchange (cooling pond of the Chernobyl NPP); (3) conditionally stagnant water bodies (separated from the main riverbed of the Pripyat River - Yanovsky and Novoshepelichesky Crawls and part of the Krasnensky former river bed); (4) semi-flowing water body (Krasnensky former river bed located outside of the dammed territory); (5) open crawls of the Pripyat river ('Schepochka' and Chernobylsky) and (6) waterway (riverbed sites of the Pripyat River). The highest levels of radionuclide concentrations were determined in fish of the stagnant water objects - 937-25907 Bq/kg (w.w.) of {sup 137}Cs and 1845-101220 Bq/kg of {sup 90}Sr. In fish of cooling pond the concentration of {sup 137}Cs registered in range 750-4200 and {sup 90}Sr - 41-512 Bq/kg. In ichthyofauna of water bodies which concern to the third group, specific activity of {sup 137}Cs and {sup 90}Sr fluctuated accordingly within range of 520-3385 and 722-6210, and in a semi-flowing reservoir - 573-2948 and 97-4484 Bq/kg. The concentrations of {sup 137}Cs in fish of the fifth and sixth groups were accordingly 25-159 and 11-224 as well as {sup 90}Sr - 36-174 and 3-14 Bq/kg. The ratio of specific activity of {sup 90}Sr/{sup 137}Cs for pray fish from all studied groups of water bodies, except the second and the sixth ones, was in range 1.5-39.7. Thus intensity of water exchange is one of the defining factors, influencing on level of radionuclide specific activity in fish, especially {sup 90}Sr - the higher the flow age, the lower the level of radioactive contamination of fish inhabiting it. Calculation of the absorbed dose rate has shown that highest radiation dose was in fish inhabiting lake

  16. Determination of the Absorbed Doses in Shanks of Interventional Radiologists

    International Nuclear Information System (INIS)

    Golnik, N.; Szczepanski, K.; Tulik, P.; Obryk, B.

    2008-01-01

    Complicated procedures of interventional radiology require usually a much longer investigation time, comparing to the conventional radiography. Moreover, interventional radiology procedures require the presence of the medical staff next to the patient in order to perform the procedure. This results in higher risk for health professionals. Even though these persons reasonably keep away from the primary X ray beam, they are under the effects of scatter radiation due to the interaction of the primary beam with the patient. The protection aprons, thyroid protectors and shielding glasses are used in order to minimize the doses for the staff, but lower parts of legs remain usually unprotected and the absorbed doses in shanks are not recorded. The paper presents the measured values of the absorbed dose in lower extremities of medical staff, involved in the procedures of interventional radiology, completed with the measurements of air kerma under the patient table. Measurements were performed in one of big hospitals in Warsaw during all the procedures performed in six weeks. Majority of the procedures constituted angioplasty or angioplasty with vascular stenting, uterine fibroid embolization and cholangiography. In the angioplasty procedure, imaging techniques are used to guide a balloon-tipped catheter into an artery and advance it to where the vessel is narrow or blocked. The balloon is then inflated to open the vessel, deflated and removed. In vascular stenting, which is often performed with angioplasty, a small wire mesh tube (a stent) is permanently placed in the newly opened artery to help it remain open. In a uterine fibroid embolization procedure, the image guidance is used in order to place an embolic agent (synthetic material) inside one or more of the blood vessels that supply the fibroid tumors with blood. As a result, these vessels become occluded, or closed off, and the fibroid tissue shrinks. Percutaneous transhepatic cholangiography is a way of examining

  17. Proton and photon absorbed-dose conversion coefficients for embryo and foetus from top-down irradiation geometry

    International Nuclear Information System (INIS)

    Chen, J.

    2007-01-01

    Absorbed-dose conversion coefficients are calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months when the mother's body is exposed to protons and photons from top-down (TOP) direction. It provides data sets in addition to other standard irradiation geometries published previously. The TOP-irradiation geometry is considered here, because high-energy particles are often peaked from the TOP direction onboard aircraft. The results show that absorbed-doses from high-energy particles could be underestimated significantly if isotropic (ISO) irradiation geometry is assumed. For protons of 100 GeV, absorbed-doses from TOP irradiation are ∼2.3-2.9 times higher than the doses from ISO irradiation for different foetal ages. For 10 GeV photons, foetal doses from TOP irradiation are ∼6.8-12 times higher than the doses from ISO irradiation. The coefficients from TOP-irradiation geometry are given in wide energy ranges, from 100 MeV to 100 GeV for protons and from 50 V to 10 GeV for photons. They can, therefore, be used in various applications whenever exposure from the TOP-irradiation direction is concerned. (authors)

  18. Absorbed doses to the main parts of eyeball due to use 90Sr + 90Y ophthalmic applicator

    International Nuclear Information System (INIS)

    Chen Lishu

    1993-05-01

    The ophthalmic radiotherapy dosimetry and some affecting factors are introduced. The distributions of absorbed doses to the main parts of a fresh eyeball such as the cornea, sclera, lens and anterior chamber, during the radiotherapy by using a 90 Sr + 90 Y ophthalmic applicator are presented. An tissue-equivalent extrapolation ionization chamber was used in the dose measurement. The reasonable doses during ophthalmic radiotherapy for different depths have been obtained. Therefore, the absorbed dose to the lens, the most sensitive organ, can be given. These data are useful for radiation protection in ophthalmic radiotherapy

  19. A Monte Carlo program converting activity distribution to absorbed dose distributions in a radionuclide treatment planning system

    International Nuclear Information System (INIS)

    Tagesson, M.; Ljungberg, M.; Strand, S.E.

    1996-01-01

    In systemic radiation therapy, the absorbed dose distribution must be calculated from the individual activity distribution. A computer code has been developed for the conversion of an arbitrary activity distribution to a 3-D absorbed dose distribution. The activity distribution can be described either analytically or as a voxel based distribution, which comes from a SPECT acquisition. Decay points are sampled according to the activity map, and particles (photons and electrons) from the decay are followed through the tissue until they either escape the patient or drop below a cut off energy. To verify the calculated results, the mathematically defined MIRD phantom and unity density spheres have been included in the code. Also other published dosimetry data were used for verification. Absorbed fraction and S-values were calculated. A comparison with simulated data from the code with MIRD data shows good agreement. The S values are within 10-20% of published MIRD S values for most organs. Absorbed fractions for photons and electrons in spheres (masses between 1 g and 200 kg) are within 10-15% of those published. Radial absorbed dose distributions in a necrotic tumor show good agreement with published data. The application of the code in a radionuclide therapy dose planning system, based on quantitative SPECT, is discussed. (orig.)

  20. Evaluation of variations in absorbed dose and image noise according to patient forms in X-ray computed tomography

    International Nuclear Information System (INIS)

    Matsubara, Kosuke; Tsujii, Hideo; Yamamoto, Tomoyuki; Koshida, Kichiro; Suzuki, Masayuki; Hayakawa, Mayumi

    2005-01-01

    Excessive radiation exposure in pediatric computed tomography (CT) scanning has become a serious problem, and it is difficult to select scan parameters for the scanning of small patients such as children. We investigated differences in absorbed dose and standard deviation (SD) in Hounsfield unit (HU) caused by differences in the form of the subject using a body-type phantom with removable body parts. Using four X-ray CT scanners, measurements were made with values from 50 mAs to 300 mAs, with slices of 50 mAs, using scan protocols that were assumed to perform thorough examinations. The results showed that the mAs values and absorbed doses were almost proportional, and the absorbed doses in the phantom without body parts were about 1.1-2.2-fold higher than those of the phantom with body parts at the same points. The SD values obtained indicated that the absorbed doses in the phantom with body parts were 0.3-0.6 times those of the phantom without body parts when the mAs values used were adjusted so that both SD values were the same. The absorbed doses in various patient forms can be estimated from these results, and they will become critical data for the selection of appropriate scan protocols. (author)

  1. Evaluation of variations in absorbed dose and image noise according to patient forms in X-ray computed tomography.

    Science.gov (United States)

    Matsubara, Kosuke; Koshida, Kichiro; Suzuki, Masayuki; Hayakawa, Mayumi; Tsujii, Hideo; Yamamoto, Tomoyuki

    2005-12-20

    Excessive radiation exposure in pediatric computed tomography (CT) scanning has become a serious problem, and it is difficult to select scan parameters for the scanning of small patients such as children. We investigated differences in absorbed dose and standard deviation (SD) in Hounsfield unit (HU) caused by differences in the form of the subject using a body-type phantom with removable body parts. Using four X-ray CT scanners, measurements were made with values from 50 mAs to 300 mAs, with slices of 50 mAs, using scan protocols that were assumed to perform thorough examinations. The results showed that the mAs values and absorbed doses were almost proportional, and the absorbed doses in the phantom without body parts were about 1.1-2.2-fold higher than those of the phantom with body parts at the same points. The SD values obtained indicated that the absorbed doses in the phantom with body parts were 0.3-0.6 times those of the phantom without body parts when the mAs values used were adjusted so that both SD values were the same. The absorbed doses in various patient forms can be estimated from these results, and they will become critical data for the selection of appropriate scan protocols.

  2. Evaluation of variations in absorbed dose and image noise according to patient forms in X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Kosuke; Tsujii, Hideo; Yamamoto, Tomoyuki [Kanazawa Univ., Hospital, Kanazawa, Ishikawa (Japan); Koshida, Kichiro; Suzuki, Masayuki; Hayakawa, Mayumi [Kanazawa Univ., Graduate School of Medical Sciences, Kanazawa, Ishikawa (Japan)

    2005-12-15

    Excessive radiation exposure in pediatric computed tomography (CT) scanning has become a serious problem, and it is difficult to select scan parameters for the scanning of small patients such as children. We investigated differences in absorbed dose and standard deviation (SD) in Hounsfield unit (HU) caused by differences in the form of the subject using a body-type phantom with removable body parts. Using four X-ray CT scanners, measurements were made with values from 50 mAs to 300 mAs, with slices of 50 mAs, using scan protocols that were assumed to perform thorough examinations. The results showed that the mAs values and absorbed doses were almost proportional, and the absorbed doses in the phantom without body parts were about 1.1-2.2-fold higher than those of the phantom with body parts at the same points. The SD values obtained indicated that the absorbed doses in the phantom with body parts were 0.3-0.6 times those of the phantom without body parts when the mAs values used were adjusted so that both SD values were the same. The absorbed doses in various patient forms can be estimated from these results, and they will become critical data for the selection of appropriate scan protocols. (author)

  3. Evaluation of absorbed radiation dose rate in a didactic X-ray equipment

    International Nuclear Information System (INIS)

    Costa, Phelipe Amaral Ferreira; Perini, Ana Paula; Neves, Lucio Pereira

    2016-01-01

    This work was performed in order to create a new didactic experiment in the X-ray apparatus of PHYWE, where the saturation current was obtained through a free air ionization chamber. The values of saturation currents were obtained in two ways. Initially, the anodic DDP was kept constant and the anodic current was varied. In the second way, the anodic current was kept constant while the anodic DDP was varied. Therefore, we were able to evaluate the dependence of the absolved dose rate in relation to the DDP and the tube current. (author)

  4. Average fetal depth in utero: data for estimation of fetal absorbed radiation dose

    International Nuclear Information System (INIS)

    Ragozzino, M.W.; Breckle, R.; Hill, L.M.; Gray, J.E.

    1986-01-01

    To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body

  5. Comparison of measurements of absorbed dose to water using a water calorimeter and ionization chambers for clinical radiotherapy photon and electron beams

    International Nuclear Information System (INIS)

    Marles, A.E.M.

    1981-01-01

    With the development of the water calorimeter direct measurement of absorbed dose in water becomes possible. This could lead to the establishment of an absorbed dose rather than an exposure related standard for ionization chambers for high energy electrons and photons. In changing to an absorbed dose standard it is necessary to investigate the effect of different parameters, among which are the energy dependence, the air volume, wall thickness and material of the chamber. The effect of these parameters is experimentally studied and presented for several commercially available chambers and one experimental chamber, for photons up to 25 MV and electrons up to 20 MeV, using a water calorimeter as the absorbed dose standard and the most recent formalism to calculate the absorbed dose with ion chambers. For electron beams, the dose measured with the calorimeter was 1% lower than the dose calculated with the chambers, independent of beam energy and chamber. For photon beams, the absorbed dose measured with the calorimeter was 3.8% higher than the absorbed dose calculated from the chamber readings. Such differences were found to be chamber and energy independent. The results for the photons were found to be statistically different from the results with the electron beams. Such difference could not be attributed to a difference in the calorimeter response

  6. Dose rate constants for new dose quantities

    International Nuclear Information System (INIS)

    Tschurlovits, M.; Daverda, G.; Leitner, A.

    1992-01-01

    Conceptual changes and new quantities made is necessary to reassess dose rate quantities. Calculations of the dose rate constant were done for air kerma, ambient dose equivalent and directional dose equivalent. The number of radionuclides is more than 200. The threshold energy is selected as 20 keV for the dose equivalent constants. The dose rate constant for the photon equivalent dose as used mainly in German speaking countries as a temporary quantity is also included. (Author)

  7. Evaluation of the absorbed doses in conditions of external and internal contamination with radionuclides

    International Nuclear Information System (INIS)

    Milivojevic, K.; Stojanovic, D.; Markovic, P.

    1981-01-01

    In experimental conditions of contamination with radionuclides of the skin and skin injuries, an evaluation of the degree of local irradiation in decontamined region and doses absorbed in organs of selective accumulating was carried out by use of mathematical models and tissue-equivalent thermoluminescent dosemeters. The evaluation of the absorbed doses based on conception, that in adequate analyses of decontamination effect, as a most efficient medico-prophilactic measure from local and total irradiation, should be taken into account the total body burden of the penetrated radionuclide, selective accumulating in critical organs or tissues, as well as the residual radioactivity in decontaminated region. (author)

  8. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  9. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    International Nuclear Information System (INIS)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A.

    2015-10-01

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  10. Dose rate to the inner ear during Moessbauer experiments

    International Nuclear Information System (INIS)

    Kliauga, P.; Khanna, S.M.

    1983-01-01

    The most widely used technique for studying vibrations of the inner ear utilises the Moessbauer effect; this requires placement of a radioactive source on the basilar membrane. This source, although small in size and less than 37 MBq(1 mCi) in strength, is placed in close proximity to sensitive receptor cells. Using a series solution for the radiation field of a rectangular source the absorbed dose rate delivered to receptor cells at various depths and at points off-axis from the centre of the source is calculated. It is concluded that the dose delivered during the course of a Moessbauer experiment may well be sufficient to damage receptor cells and cause a loss of response. (author)

  11. Absorbed Dose and Effective Dose for Lung Cancer Image Guided Radiation Therapy(IGRT) using CBCT and 4D-CBCT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Yong; Lee, Woo Suk; Koo, Ki Lae; Kim, Joo Seob; Lee, Sang Hyeon [Dept. of Radiation Oncology, GangNeung Asan Hospital, Gangneung (Korea, Republic of)

    2016-06-15

    To evaluate the results of absorbed and effective doses using CBCT and 4D-CBCT settings for lung cancer. This experimental study. Measurements were performed using a Anderson rando phantom with OSLD(optically stimulated luminescent dosimeters). It was performed computed tomography(Lightspeed GE, USA) in order to express the major organs of the human body. Measurements were obtained a mean value is repeated three times each. Evaluations of effective dose and absorbed dose were performed the CL-IX-Thorax mode and Truebeam-Thorax mode CBCT. Additionally, compared Truebeam-Thorax mode CBCT with Truebeam-Thorax mode 4D-CBCT(Four-dimensional Cone Beam Computed Tomography). Average absorbed dose in the CBCT of CL-IX was measured in lung 2.505cGy, heart 2.595cGy, liver 2.145cGy, stomach 1.934cGy, skin 2.233cGy, in case of Truebeam, It was measured lung 1.725cGy, heart 2.034cGy, liver 1.616cGy, stomach 1.470cGy, skin 1.445cGy. In case of 4D-CBCT, It was measured lung 3.849cGy, heart 4.578cGy, liver 3.497cGy, stomach 3.179cGy, skin 3.319cGy Average effective dose, considered tissue weighting and radiation weighting, in the CBCT of CL-IX was measured lung 2.164mSv, heart 2.241mSVv, liver 0.136mSv, stomach 1.668mSv, skin 0.009mSv, in case of Turebeam, it was measured lung 1.725mSv, heart 1.757mSv, liver 0.102mSv, stomach 1.270mSv, skin 0.005mSv, In case of 4D-CBCT, It was measured lung 3.326mSv, heart 3.952mSv, liver 0.223mSv, stomach 2.747mSv, skin 0.013mSv. As a result, absorbed dose and effective Dose in the CL-IX than Truebeam was higher about 1.3 times and in the 4D-CBCT Truebeam than CBCT of Truebeam was higher about 2.2times However, a large movement of the patient and respiratory gated radiotherapy may be more accurate treatment in 4D-CBCT. Therefore, it will be appropriate to selectively used.

  12. Utilization of radiation protection gear for absorbed dose reduction: an integrative literature review

    International Nuclear Information System (INIS)

    Soares, Flavio Augusto Penna; Flor, Rita de Cassia; Pereira, Aline Garcia

    2011-01-01

    Objective: The present study was aimed at evaluating the relation between the use of radiation protection gear and the decrease in absorbed dose of ionizing radiation, thereby reinforcing the efficacy of its use by both the patients and occupationally exposed personnel. Materials and Methods: The integrative literature review method was utilized to analyze 21 articles, 2 books, 1 thesis, 1 monograph, 1 computer program, 4 pieces of database research (Instituto Brasileiro de Geografia e Estatistica and Departamento de Informatica do Sistema Unico de Saude) and 2 sets of radiological protection guidelines. Results: Theoretically, a reduction of 86% to 99% in the absorbed dose is observed with the use of radiation protection gear. In practice, however, the reduction may achieve 88% in patients submitted to conventional radiology, and 95% in patients submitted to computed tomography. In occupationally exposed individuals, the reduction is around 90% during cardiac catheterization, and 75% during orthopedic surgery. Conclusion: According to findings of several previous pieces of research, the use of radiation protection gear is a low-cost and effective way to reduce absorbed dose both for patients and occupationally exposed individuals. Thus, its use is necessary for the implementation of effective radioprotection programs in radiodiagnosis centers. (author)

  13. Spatial distribution of absorbed dose onboard of International Space Station

    International Nuclear Information System (INIS)

    Jadrnickova, I.; Spumy, F.; Tateyama, R.; Yasuda, N.; Kawashima, H.; Kurano, M.; Uchihori, Y.; Kitamura, H.; Akatov, Yu.; Shurshakov, V.; Kobayashi, I.; Ohguchi, H.; Koguchi, Y.

    2009-01-01

    The passive detectors (LD and PNTD) were exposed onboard of Russian Service Module Qn the International Space Station (ISS) from August 2004 to October 2005 (425 days). The detectors were located at 6 different positions inside the Service Module and also in 32 pockets on the surface of the spherical tissue-equivalent phantom located in crew cabin. Distribution of absorbed doses and dose equivalents measured with passive detectors, as well as LET spectra of fluences of registered particles, are presented as the function of detectors' location. The variation of dose characteristics for different locations can be up to factor of 2. In some cases, data measured with passive detectors are also compared with the data obtained by means of active instruments. (authors)

  14. Calculation of absorbed dose of anchorage-dependent cells from internal beta-rays irradiation

    International Nuclear Information System (INIS)

    Chen Jianwei; Huang Gang; Li Shijun

    2001-01-01

    Objective: To elicit the formula of internal dosimetry in anchorage-dependent cells by beta-emitting radionuclides from uniformly distributed volume sources. Methods: By means of the definition of absorbed dose and the MIRD (Medical International Radiation Dose) scheme the formula of internal dosimetry was reasonably deduced. Firstly, studying the systems of suspension culture cells. Then, taking account of the speciality of the systems of the anchorage-dependent cells and the directions of irradiation, the absorbed dose of anchorage -dependent cells was calculated by the accumulated radioactivity, beta-ray energy, and the volume of the cultured systems. Results: The formula of internal dosimetry of suspension culture cells and anchorage-dependent cells were achieved. At the same time, the formula of internal dosimetry of suspension culture cells was compared with that of MIRD and was confirmed accurate. Conclusion: The formula of internal dosimetry is concise, reliable and accurate

  15. Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures.

    Science.gov (United States)

    Kloeze, C; Klompenhouwer, E G; Brands, P J M; van Sambeek, M R H M; Cuypers, P W M; Teijink, J A W

    2014-03-01

    Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  16. Sensors of absorbed dose of ionizing radiation based on mosfet

    Directory of Open Access Journals (Sweden)

    Perevertaylo V. L.

    2010-10-01

    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  17. Monte Carlo calculation of dose rate conversion factors for external exposure to photon emitters in soil

    CERN Document Server

    Clouvas, A; Antonopoulos-Domis, M; Silva, J

    2000-01-01

    The dose rate conversion factors D/sub CF/ (absorbed dose rate in air per unit activity per unit of soil mass, nGy h/sup -1/ per Bq kg/sup -1/) are calculated 1 m above ground for photon emitters of natural radionuclides uniformly distributed in the soil. Three Monte Carlo codes are used: 1) The MCNP code of Los Alamos; 2) The GEANT code of CERN; and 3) a Monte Carlo code developed in the Nuclear Technology Laboratory of the Aristotle University of Thessaloniki. The accuracy of the Monte Carlo results is tested by the comparison of the unscattered flux obtained by the three Monte Carlo codes with an independent straightforward calculation. All codes and particularly the MCNP calculate accurately the absorbed dose rate in air due to the unscattered radiation. For the total radiation (unscattered plus scattered) the D/sub CF/ values calculated from the three codes are in very good agreement between them. The comparison between these results and the results deduced previously by other authors indicates a good ag...

  18. A comparison of 2D and 3D kidney absorbed dose measures in patients receiving 177Lu-DOTATATE

    Directory of Open Access Journals (Sweden)

    Kathy Willowson

    2018-06-01

    Full Text Available Objective(s: To investigate and compare quantitative accuracy of kidney absorbed dose measures made from both 2D and 3D imaging in patients receiving 177LuDOTATATE (Lutate for treatment of neuroendocrine tumours (NETs. Methods: Patients receiving Lutate therapy underwent both whole body planar imaging and SPECT/CT imaging over the kidneys at time points 0.5, 4, 24, and 96-120 hours after injection. Planar data were corrected for attenuation using transmission data, and were converted to units of absolute activity via two methods, using either a calibration standard in the field of view or relative to pre-voiding image total counts. Hand drawn regions of interest were used to generate time activity curves and kidney absorbed dose estimates in OLINDA-EXM. Fully quantitative SPECT data were generated using CT-derived corrections for both scatter and attenuation, before correction for dead time and application of a camera specific sensitivity factor to convert data to units of absolute activity. Volumes of interest were defined for kidney using the co-registered x-ray CT, before time activity curves and absorbed dose measures were generated in OLINDA-EXM, both with and without corrections made to the model for patient specific kidney volumes. Quantitative SPECT data were also used to derive dose maps through dose kernel convolution (DKC, which was treated as the gold standard. Results: A total of 50 studies were analysed, corresponding to various cycles of treatment from 21 patients. Planar absorbed dose estimates were consistently higher than SPECT derived estimates by, on average, a factor of 3. Conclusion: Quantitative SPECT is considered the gold standard approach for organ specific dosimetry however often relies on in house software. As such planar methods for estimating absorbed dose are much more widely available, and in particular, are often the only source of reference in previously published data. For the case of Lutate dosimetry, planar

  19. Radiation-absorbed doses and energy imparted from panoramic tomography, cephalometric radiography, and occlusal film radiography in children

    International Nuclear Information System (INIS)

    Bankvall, G.; Hakansson, H.A.

    1982-01-01

    The absorbed doses and energy imparted from radiographic examinations of children, using panoramic tomography (PTG), cephalometric radiography (CPR), and maxillary frontal occlusal overview (FOO), were examined. The absorbed dose at various sites of the head were measured with TL dosimeters in a phantom and in patients. The energy imparted was calculated from measurements of areal exposure using a planparallel ionization chamber. The maximum absorbed doses for panoramic tomography were located around the lateral rotation center, for cephalometric radiography in the left (tube side) parotid region, and for frontal occlusal radiography in the nose. The absorbed doses in the eyes, thyroid gland, and skin are discussed and compared with previous reports and, for the most part, are found to be in agreement. The mean energy imparted from all three examination methods is 5 mJ with about 57 percent from panoramic, 33 percent from cephalometric, and 10 percent from frontal occlusal examinations. The energy imparted from cephalometric radiography can be reduced to about 10 percent with the use of an improved examination technique, leaving panoramic tomography responsible for contributing about 80 percent of the total energy imparted

  20. Standard Guide for Absorbed-Dose Mapping in Radiation Processing Facilities

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This document provides guidance in determining absorbed-dose distributions in products, materials or substances irradiated in gamma, X-ray (bremsstrahlung) and electron beam facilities. Note 1—For irradiation of food and the radiation sterilization of health care products, other specific ISO and ISO/ASTM standards containing dose mapping requirements exist. For food irradiation, see ISO/ASTM 51204, Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing and ISO/ASTM 51431, Practice for Dosimetry in Electron and Bremsstrahlung Irradiation Facilities for Food Processing. For the radiation sterilization of health care products, see ISO 11137: 1995, Sterilization of Health Care Products Requirements for Validation and Routine Control Radiation Sterilization. In those areas covered by ISO 11137, that standard takes precedence. ISO/ASTM Practice 51608, ISO/ASTM Practice 51649, and ISO/ASTM Practice 51702 also contain dose mapping requirements. 1.2 Methods of analyzing the dose map data ar...

  1. Application of airborne gamma spectrometric survey data to estimating terrestrial gamma-ray dose rates: An example in California

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Revzan, K.L.; Smith, A.R.

    1992-01-01

    The authors examine the applicability of radioelement data from the National Aerial Radiometric Reconnaissance (NARR) to estimate terrestrial gamma-ray absorbed dose rates, by comparing dose rates calculated from aeroradiometric surveys of U, Th, and K concentrations in 1 x 2 degree quadrangles with dose rates calculated from a radiogeologic data base and the distribution of lithologies in California. Gamma-ray dose rates increase generally from north to south following lithological trends. Low values of 25--30 nG/h occur in the northernmost quadrangles where low-radioactivity basaltic and ultramafic rocks predominate. Dose rates then increase southward due to the preponderance of clastic sediments and basic volcanics of the Franciscan Formation and Sierran metamorphics in north central and central California, and to increasing exposure southward of the Sierra Nevada batholith, Tertiary marine sedimentary rocks, intermediate to acidic volcanics, and granitic rocks of the Coast Ranges. High values, to 100 nGy/h occur in southeastern California, due primarily to the presence of high-radioactivity Precambrian and pre Cenozoic metamorphic rocks. Lithologic-based estimates of mean dose rates in the quadrangles generally match those from aeroradiometric data, with statewide means of 63 and 60 nGy/h, respectively. These are intermediate between a population-weighted global average of 51 nGy/h and a weighted continental average of 70 nGy/h, based on the global distribution of rock types. The concurrence of lithologically- and aeroradiometrically- determined dose rates in California, with its varied geology and topography encompassing settings representative of the continents, indicates that the NARR data are applicable to estimates of terrestrial absorbed dose rates from natural gamma emitters

  2. Experimental verification of the air kerma to absorbed dose conversion factor Cw,u.

    Science.gov (United States)

    Mijnheer, B J; Wittkämper, F W; Aalbers, A H; van Dijk, E

    1987-01-01

    In a recently published code of practice for the dosimetry of high-energy photon beams, the absorbed dose to water is determined using an ionization chamber having an air kerma calibration factor and applying the air kerma to absorbed dose conversion factor Cw,u. The consistency of these Cw,u values has been determined for four commonly employed types of ionization chambers in photon beams with quality varying between 60Co gamma-rays and 25 MV X-rays. Using a graphite calorimeter, Cw,u has been determined for a graphite-walled ionization chamber (NE 2561) for the same qualities. The values of Cw,u determined with the calorimeter are within the experimental uncertainty equal to Cw,u values determined according to any of the recent dosimetry protocols.

  3. Selective fallopian tube catheterisation in female infertility: clinical results and absorbed radiation dose

    International Nuclear Information System (INIS)

    Nakamura, K.; Ishiguchi, T.; Maekoshi, H.; Ando, Y.; Tsuzaka, M.; Tamiya, T.; Suganuma, N.; Ishigaki, T.

    1996-01-01

    Clinical results of fluoroscopic fallopian tube catheterisation and absorbed radiation doses during the procedure were evaluated in 30 infertility patients with unilateral or bilateral tubal obstruction documented on hysterosalpingography. The staged technique consisted of contrast injection through an intrauterine catheter with a vacuum cup device, ostial salpingography with the wedged catheter, and selective salpingography with a coaxial microcatheter. Of 45 fallopian tubes examined, 35 (78 %) were demonstrated by the procedure, and at least one tube was newly demonstrated in 26 patients (87 %). Six of these patients conceived spontaneously in the follow-up period of 1-11 months. Four pregnancies were intrauterine and 2 were ectopic. This technique provided accurate and detailed information in the diagnosis and treatment of tubal obstruction in infertility patients. The absorbed radiation dose to the ovary in the average standardised procedure was estimated to be 0.9 cGy. Further improvement in the X-ray equipment and technique is required to reduce the radiation dose. (orig.). With 3 figs., 3 tabs

  4. Renal function affects absorbed dose to the kidneys and haematological toxicity during {sup 177}Lu-DOTATATE treatment

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Johanna; Berg, Gertrud [Sahlgrenska University Hospital, Department of Oncology, Goeteborg (Sweden); Waengberg, Bo [Sahlgrenska University Hospital, Department of Surgery, Goeteborg (Sweden); Larsson, Maria [University of Gothenburg, Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, Goeteborg (Sweden); Forssell-Aronsson, Eva; Bernhardt, Peter [University of Gothenburg, Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, Goeteborg (Sweden); Sahlgrenska University Hospital, Department of Medical Physics and Medical Bioengineering, Goeteborg (Sweden)

    2015-05-01

    Peptide receptor radionuclide therapy (PRRT) has become an important treatment option in the management of advanced neuroendocrine tumours. Long-lasting responses are reported for a majority of treated patients, with good tolerability and a favourable impact on quality of life. The treatment is usually limited by the cumulative absorbed dose to the kidneys, where the radiopharmaceutical is reabsorbed and retained, or by evident haematological toxicity. The aim of this study was to evaluate how renal function affects (1) absorbed dose to the kidneys, and (2) the development of haematological toxicity during PRRT treatment. The study included 51 patients with an advanced neuroendocrine tumour who received {sup 177}Lu-DOTATATE treatment during 2006 - 2011 at Sahlgrenska University Hospital in Gothenburg. An average activity of 7.5 GBq (3.5 - 8.2 GBq) was given at intervals of 6 - 8 weeks on one to five occasions. Patient baseline characteristics according to renal and bone marrow function, tumour burden and medical history including prior treatment were recorded. Renal and bone marrow function were then monitored during treatment. Renal dosimetry was performed according to the conjugate view method, and the residence time for the radiopharmaceutical in the whole body was calculated. A significant correlation between inferior renal function before treatment and higher received renal absorbed dose per administered activity was found (p < 0.01). Patients with inferior renal function also experienced a higher grade of haematological toxicity during treatment (p = 0.01). The residence time of {sup 177}Lu in the whole body (range 0.89 - 3.0 days) was correlated with grade of haematological toxicity (p = 0.04) but not with renal absorbed dose (p = 0.53). Patients with inferior renal function were exposed to higher renal absorbed dose per administered activity and developed a higher grade of haematological toxicity during {sup 177}Lu-DOTATATE treatment. The study confirms the

  5. Radiation sterilization of absorbent cotton and of absorbent gauze

    International Nuclear Information System (INIS)

    Hosobuchi, Kazunari; Oka, Mitsuru; Kaneko, Akira; Ishiwata, Hiroshi.

    1986-01-01

    The bioburden of absorbent cotton and of absorbent gauze and their physical and chemical characteristics after irradiation are investigated. The survey conducted on contaminants of 1890 cotton samples from 53 lots and 805 gauze samples from 56 lots showed maximum numbers of microbes per g of the cotton and gauze were 859 (an average of 21.4) and 777 (an average of 42.2), respectively. Isolation and microbiological and biochemical tests of representative microbes indicated that all of them, except one, were bacilli. The sterilization dose at 10 -6 of sterlity assurance level was found to be 2.0 Mrad when irradiated the spores loaded on paper strips and examined populations having graded D values from 0.10 to 0.28 Mrad. The sterilization dose would be about 1.5 Mrad if subjected the average numbers of contaminants observed in this study to irradiation. No significant differences were found between the irradiated samples and control up to 2 Mrad in tensile strength, change of color, absorbency, sedimentation rate, soluble substances, and pH of solutions used for immersion and other tests conventionally used. These results indicate that these products can be sterilized by irradiation. (author)

  6. Absorbed dose by thyroid in case of nuclear accidents

    International Nuclear Information System (INIS)

    Campos, Laelia; Attie, Marcia Regina Pereira; Amaral, Ademir

    2011-01-01

    Radioisotopes of iodine are produced in abundance in nuclear fission reactions, and great amounts of radioiodine may be released into the environment in case of a nuclear reactor accident. Thyroid gland is among the most radiosensitive organs due to its capacity to concentrate iodine. The aim of this work was to evaluate the importance of contributions of internally deposited iodines ( 131 I, 132 I, 133 I, 134 I and 135 I) to the dose absorbed to thyroid follicle and to the whole organ, after internal contamination by those isotopes. For internal dose calculation, the code of particles transport MCNP4C was employed. The results showed that, in case of nuclear accidents, the contribution of short-lived iodines for total dose is about 45% for thyroid of newborn and about 40% for thyroid of adult. Thus, these contributions should not be neglected in a prospective evaluation of risks associated to internal contamination by radioactive iodine. (author)

  7. A numerical analysis of aspects of absorbed dose in the vicinity of the interface of different materials

    Energy Technology Data Exchange (ETDEWEB)

    Tada, J [Tsukuba Univ., (Japan); Hirayama, H [National Lab. High Enregy Phys. (Japan); Katoh, K [Ibaraki Pref. Univ. Health Sci., (Japan)

    1997-12-31

    In the measurement and/or evaluation of the absorbed dose where the charged particle distribution is far from equilibrium, knowledge on the microscopic spatial distribution of the charged particle fluence is important. Spatial distribution of secondary electrons in the vicinity of an interface of materials and the values of the absorbed dose in these regions are investigated with a monte-Carlo simulation code EGS 4. There were experiments on spatial variation of the absorbed dose in the vicinity of an interface of materials. However, the behaviour of secondary electrons were discussed only broadly and qualitatively. In this study, behaviour of the secondary electrons was analysed to clarify contribution of ruling interactions to generate secondary electrons, and influence of the interface on the energy spectra of secondary electrons. 11 figs.

  8. Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products; Sistemas dosimetricos de altas dosis, tasa de dosis y uniformidad de dosis en alimentos y producto medico

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.; Vivanco, M.; Castro, E., E-mail: jvargas@ipen.gob.pe [Instituto Peruano de Energia Nuclear, Av. Canada 1470, San Borja, Lima (Peru)

    2014-08-15

    In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

  9. Absorbed Dose in the Uterus of a Three Months Pregnant Woman Due to 131I

    International Nuclear Information System (INIS)

    Vega-Carrillo, Hector Rene; Manzanares-Acuna, Eduardo; Hernandez-Davila, Victor Martin; Arcos-Pichardo, Areli; Barquero, Raquel; Iniguez, M. Pilar

    2006-01-01

    The use of 131I is widely used in diagnostic and treatment of patients. If the patient is pregnant the 131I presence in the thyroid it becomes a source of constant exposition to other organs and the fetus. In this study the absorbed dose in the uterus of a 3 months pregnant woman with 131I in her thyroid gland has been calculated. The dose was determined using Monte Carlo methods in which a detailed model of the woman has been developed. The dose was also calculated using a simple procedure that was refined including the photons' attenuation in the woman organs and body. To verify these results an experiment was carried out using a neck phantom with 131I. Comparing the results it was found that the simple calculation tend to overestimate the absorbed dose, by doing the corrections due to body and organs photon attenuation the dose is 0.14 times the Monte Carlo estimation

  10. Comparison of ESD and major organ absorbed doses of 5 year old standard guidekines and clinical exposure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, A Ram; Ahn, Sung Min [Dept. of Radiological Science, The Graduate School, Gachon University, Incheon (Korea, Republic of); Lee, In Ja [Dept. of Radiologic technology, Dongnam health University, Suwon (Korea, Republic of)

    2017-09-15

    Pediatrics are more sensibility to radiation than adults and because they are organs that are not completely grown, they have a life expectancy that can be adversely affected by exposure. Therefore, the management of exposure dose is more important than the case of adult. The purpose of this study was to determine the suitability of the 10 year old phantom for the 5 year old pediatric's recommendation and the incident surface dose, and to measure the organ absorbed dose. This study is compared the organ absorbed dose and the entrance surface dose in the clinical conditions at 5 and 10 years old pediatric. Clinical 5 year old condition was slightly higher than recommendation condition and 10 year old condition was very high. In addition, recommendation condition ESD was found to be 43% higher than the ESD of the 5 year old group and the ESD of the 10 year old group was 126% higher than that of the 5 year old group. The recommended ESD at 5 years old and the ESD according to clinical imaging conditions were 31.6%. There was no significant difference between the 5 year old recommended exposure conditions and the organ absorbed dose due to clinical exposure conditions, but there was a large difference between the Chest and Pelvic. However, it was found that there was a remarkable difference when comparing the organ absorbed dose by 10 year clinical exposure conditions. Therefore, more detailed standard exposure dose for the recommended dose of pediatric should be studied.

  11. Comparison of ESD and major organ absorbed doses of 5 year old standard guidekines and clinical exposure conditions

    International Nuclear Information System (INIS)

    Kang, A Ram; Ahn, Sung Min; Lee, In Ja

    2017-01-01

    Pediatrics are more sensibility to radiation than adults and because they are organs that are not completely grown, they have a life expectancy that can be adversely affected by exposure. Therefore, the management of exposure dose is more important than the case of adult. The purpose of this study was to determine the suitability of the 10 year old phantom for the 5 year old pediatric's recommendation and the incident surface dose, and to measure the organ absorbed dose. This study is compared the organ absorbed dose and the entrance surface dose in the clinical conditions at 5 and 10 years old pediatric. Clinical 5 year old condition was slightly higher than recommendation condition and 10 year old condition was very high. In addition, recommendation condition ESD was found to be 43% higher than the ESD of the 5 year old group and the ESD of the 10 year old group was 126% higher than that of the 5 year old group. The recommended ESD at 5 years old and the ESD according to clinical imaging conditions were 31.6%. There was no significant difference between the 5 year old recommended exposure conditions and the organ absorbed dose due to clinical exposure conditions, but there was a large difference between the Chest and Pelvic. However, it was found that there was a remarkable difference when comparing the organ absorbed dose by 10 year clinical exposure conditions. Therefore, more detailed standard exposure dose for the recommended dose of pediatric should be studied

  12. Investigation of absorbed radiation dose in refraction-enhanced breast tomosynthesis by a Laue case analyser

    International Nuclear Information System (INIS)

    Sato, H.; Ando, M.; Shimao, D.

    2011-01-01

    An early diagnosis system for breast cancer using refraction-enhanced breast tomosynthesis is under development. Tomograms of breast specimens based on refraction-contrast were demonstrated using the simplest shift-and-add tomosynthesis algorithm. Raw projection image data of breast specimens for tomosynthesis were acquired for a total of 51 views over an angle of 50 deg., in increments of 1 deg., by rotating the object. The incident X ray was monochromatic synchrotron radiation with 20 keV. The purpose of this study was to estimate the absorbed dose of a new X-ray imaging method. As breast cancer almost always arises in glandular breast tissue, the average absorbed dose in such glandular tissue should be measured to estimate the radiation risk associated with mammography. The absorbed dose of the mammary gland due to monochromatic X rays was calculated by the Monte Carlo method, and the optimal X ray energy range for refraction-enhanced breast tomosynthesis was investigated through actual measurements. Compared with the conventional method, it was found to be below one-sixth per inspection. (authors)

  13. SU-G-TeP2-05: Development of a Thimble Calorimeter for Absorbed Dose to Water Characterized in MV Photons

    International Nuclear Information System (INIS)

    Chen-Mayer, H; Bateman, F; Tosh, R; Bergstrom, P

    2016-01-01

    Purpose: To develop a thimble sized polystyrene calorimeter for use from kV to MV photons, as a primary reference standard for applications from diagnostic CT imaging to therapy beam dose determination. Methods: A polystyrene calorimeter about 1.5 cm diameter embedded with small thermistors was characterized in a 6 MV photon beam from a clinical accelerator at 5 nominal dose rates from 0.8 to 4 Gy/min. Irradiations were delivered with beam on/off cycles first at 60 s and then at 20 s. Two sets of phantom conditions were evaluated: 1) in a 30 cm diameter polyethylene cylinder, and 2) in 10 cm depth of a 30 cm water phantom. The temperature waveforms were recorded and analyzed for temperature rise, arriving at a dose to polystyrene. This value is compared with the result of measurements under identical conditions using an ionization chamber calibrated for absorbed dose to water. Monte Carlo simulations were performed on the measurement systems to estimate such a ratio. Results: The ratio of the dose determined by the calorimeter to the dose reported by the ionization chamber was aggregated from all 5 dose rates. The 60 s results show a much elevated response in both phantoms compared to their respective expected results based on simulation. This deviation was reduced when the on/off cycles were shortened to 20 s. This behavior was possibly due to the heat conduction effects in the small calorimeter body. Finite element modeling is being conducted to simulate this effect. Conclusion: A small solid plastic calorimeter offers the convenience of a portable absorbed dose standard based on direct measurement of energy deposition, but comes at the expense of heat transfer complications which need to be characterized. This work offers preliminary evidence of the behavior and quantitative assessment of the issues to be resolved in future investigations.

  14. SU-G-TeP2-05: Development of a Thimble Calorimeter for Absorbed Dose to Water Characterized in MV Photons

    Energy Technology Data Exchange (ETDEWEB)

    Chen-Mayer, H; Bateman, F; Tosh, R; Bergstrom, P [NIST, Gaithersburg, MD (United States)

    2016-06-15

    Purpose: To develop a thimble sized polystyrene calorimeter for use from kV to MV photons, as a primary reference standard for applications from diagnostic CT imaging to therapy beam dose determination. Methods: A polystyrene calorimeter about 1.5 cm diameter embedded with small thermistors was characterized in a 6 MV photon beam from a clinical accelerator at 5 nominal dose rates from 0.8 to 4 Gy/min. Irradiations were delivered with beam on/off cycles first at 60 s and then at 20 s. Two sets of phantom conditions were evaluated: 1) in a 30 cm diameter polyethylene cylinder, and 2) in 10 cm depth of a 30 cm water phantom. The temperature waveforms were recorded and analyzed for temperature rise, arriving at a dose to polystyrene. This value is compared with the result of measurements under identical conditions using an ionization chamber calibrated for absorbed dose to water. Monte Carlo simulations were performed on the measurement systems to estimate such a ratio. Results: The ratio of the dose determined by the calorimeter to the dose reported by the ionization chamber was aggregated from all 5 dose rates. The 60 s results show a much elevated response in both phantoms compared to their respective expected results based on simulation. This deviation was reduced when the on/off cycles were shortened to 20 s. This behavior was possibly due to the heat conduction effects in the small calorimeter body. Finite element modeling is being conducted to simulate this effect. Conclusion: A small solid plastic calorimeter offers the convenience of a portable absorbed dose standard based on direct measurement of energy deposition, but comes at the expense of heat transfer complications which need to be characterized. This work offers preliminary evidence of the behavior and quantitative assessment of the issues to be resolved in future investigations.

  15. Influence of lead apron shielding on absorbed doses from cone-beam computed tomography

    International Nuclear Information System (INIS)

    Rottke, Dennis; Andersson, Jonas; Ejima, Ken-Ichiro; Sawada, Kunihiko; Schulze, Dirk

    2017-01-01

    The aim of the present work was to investigate absorbed and to calculate effective doses (EDs) in cone-beam computed tomography (CBCT). The study was conducted using examination protocols with and without lead apron shielding. A full-body male RANDO"R phantom was loaded with 110 GR200A thermoluminescence dosemeter chips at 55 different sites and set up in two different CBCT systems (CS 9500"R, ProMax"R 3D). Two different protocols were performed: the phantom was set up (1) with and (2) without a lead apron. No statistically significant differences in organ and absorbed doses from regions outside the primary beam could be found when comparing results from exposures with and without lead apron shielding. Consequently, calculating the ED showed no significant differences between the examination protocols with and without lead apron shielding. For the ProMax"R 3D with shielding, the ED was 149 μSv, and for the examination protocol without shielding 148 μSv (SD = 0.31 μSv). For the CS 9500"R, the ED was 88 and 86 μSv (SD = 0.95 μSv), respectively, with and without lead apron shielding. The results revealed no statistically significant differences in the absorbed doses between examination with and without lead apron shielding, especially in organs outside the primary beam. (authors)

  16. Calculation of absorbed dose and biological effectiveness from photonuclear reactions in a bremsstrahlung beam of end point 50 MeV.

    Science.gov (United States)

    Gudowska, I; Brahme, A; Andreo, P; Gudowski, W; Kierkegaard, J

    1999-09-01

    The absorbed dose due to photonuclear reactions in soft tissue, lung, breast, adipose tissue and cortical bone has been evaluated for a scanned bremsstrahlung beam of end point 50 MeV from a racetrack accelerator. The Monte Carlo code MCNP4B was used to determine the photon source spectrum from the bremsstrahlung target and to simulate the transport of photons through the treatment head and the patient. Photonuclear particle production in tissue was calculated numerically using the energy distributions of photons derived from the Monte Carlo simulations. The transport of photoneutrons in the patient and the photoneutron absorbed dose to tissue were determined using MCNP4B; the absorbed dose due to charged photonuclear particles was calculated numerically assuming total energy absorption in tissue voxels of 1 cm3. The photonuclear absorbed dose to soft tissue, lung, breast and adipose tissue is about (0.11-0.12)+/-0.05% of the maximum photon dose at a depth of 5.5 cm. The absorbed dose to cortical bone is about 45% larger than that to soft tissue. If the contributions from all photoparticles (n, p, 3He and 4He particles and recoils of the residual nuclei) produced in the soft tissue and the accelerator, and from positron radiation and gammas due to induced radioactivity and excited states of the nuclei, are taken into account the total photonuclear absorbed dose delivered to soft tissue is about 0.15+/-0.08% of the maximum photon dose. It has been estimated that the RBE of the photon beam of 50 MV acceleration potential is approximately 2% higher than that of conventional 60Co radiation.

  17. Calculation of absorbed dose and biological effectiveness from photonuclear reactions in a bremsstrahlung beam of end point 50 MeV

    International Nuclear Information System (INIS)

    Gudowska, I.; Brahme, A.; Andreo, P.; Gudowski, W.; Kierkegaard, J.

    1999-01-01

    The absorbed dose due to photonuclear reactions in soft tissue, lung, breast, adipose tissue and cortical bone has been evaluated for a scanned bremsstrahlung beam of end point 50 MeV from a racetrack accelerator. The Monte Carlo code MCNP4B was used to determine the photon source spectrum from the bremsstrahlung target and to simulate the transport of photons through the treatment head and the patient. Photonuclear particle production in tissue was calculated numerically using the energy distributions of photons derived from the Monte Carlo simulations. The transport of photoneutrons in the patient and the photoneutron absorbed dose to tissue were determined using MCNP4B; the absorbed dose due to charged photonuclear particles was calculated numerically assuming total energy absorption in tissue voxels of 1 cm 3 . The photonuclear absorbed dose to soft tissue, lung, breast and adipose tissue is about (0.11-0.12)±0.05% of the maximum photon dose at a depth of 5.5 cm. The absorbed dose to cortical bone is about 45% larger than that to soft tissue. If the contributions from all photoparticles (n, p, 3 He and 4 He particles and recoils of the residual nuclei) produced in the soft tissue and the accelerator, and from positron radiation and gammas due to induced radioactivity and excited states of the nuclei, are taken into account the total photonuclear absorbed dose delivered to soft tissue is about 0.15±0.08% of the maximum photon dose. It has been estimated that the RBE of the photon beam of 50 MV acceleration potential is approximately 2% higher than that of conventional 60 Co radiation. (author)

  18. Dose rate correction in medium dose rate brachytherapy for carcinoma cervix

    International Nuclear Information System (INIS)

    Patel, F.D.; Negi, P.S.; Sharma, S.C.; Kapoor, R.; Singh, D.P.; Ghoshal, S.

    1998-01-01

    Purpose: To establish the magnitude of brachytherapy dose reduction required for stage IIB and III carcinoma cervix patients treated by external radiation and medium dose rate (MDR) brachytherapy at a dose rate of 220±10 cGy/h at point A.Materials and methods: In study-I, at the time of MDR brachytherapy application at a dose rate of 220±10 cGy/h at point A, patients received either 3060 cGy, a 12.5% dose reduction (MDR-12.5), or 2450 cGy, a 30% dose reduction (MDR-30), to point A and they were compared to a group of previously treated LDR patients who received 3500 cGy to point A at a dose rate of 55-65 cGy/h. Study-II was a prospective randomized trial and patients received either 2450 cGy, a 30% dose reduction (MDR-II (30)) or 2800 cGy, a 20% dose reduction (MDR-II (20)), at point A. Patients were evaluated for local control of disease and morbidity. Results: In study-I the 5-year actuarial local control rate in the MDR-30 and MDR-12.5 groups was 71.7±10% and 70.5±10%, respectively, compared to 63.4±10% in the LDR group. However, the actuarial morbidity (all grades) in the MDR-12.5 group was 58.5±14% as against 34.9±9% in the LDR group (P 3 developed complication as against 62.5% of those receiving a rectal BED of (140 3 (χ 2 =46.43; P<0.001). Conclusion: We suggest that at a dose rate of 220±10 cGy/h at point A the brachytherapy dose reduction factor should be around 30%, as suggested by radiobiological data, to keep the morbidity as low as possible without compromising the local control rates. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Automation of the monitoring in real time of the absorbed dose rate in air due to the environmental gamma radiation in Cuba

    International Nuclear Information System (INIS)

    Dominguez L, O.; Capote F, E.; Carrazana G, J.A.; Manzano de Armas, J.F.; Alonso A, D.; Prendes A, M.; Zerquera, J.T.; Caveda R, C.A.; Kalberg, O.; Fabelo B, O.; Montalvan E, A.; Cartas A, H.; Leyva F, J.C.

    2006-01-01

    The Center of Protection and Hygiene of the Radiations (CPHR) like center rector of the National Net of Environmental Radiological Surveillance (RNVRA), it has strengthened their detection capacity and of answer before a situation of radiological emergency. The measurements of the absorbed dose rate in air due to the environmental gamma radiation in the main stations of the Net are obtained in real time and the CPHR receives the data coming from these posts at one time relatively short. To improve the operability of the RNVRA it was necessary to complete the facilities of existent monitoring using 4 automatic measurement stations with probes of gamma detection, implementing in this way a measurement system on real time. On the other hand the software were developed: GenironProbeFech, to obtain the data of the probes, DataMail for the shipment of the same ones by electronic mail and GammaRed that receives and processes the data in the rector center. (Author)

  20. Radiation absorbed doses at radiographic examination of third molars.

    Science.gov (United States)

    Rehnmark-Larsson, S; Stenström, B; Julin, P; Richter, S

    1982-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. In the maxilla three, and in the mandible four different projections were used; also an extraoral lateral view. The greatest thyroid dose, 35 muGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. the thyroid dose from an extraoral lateral view with high sensitivity screens was 3.7 muGy. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. The corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50%. the Ekta-Speed film required approximately 40% lower exposure than the Ultra-Speed film. Without shielding the gonadal doses from a complete examination of four third molars were of the same order of magnitude as from a full survey with intraoral films, i.e. 3-7 muGy. A horizontal radiation shield reduced the thyroid doses by between 12 and 46% and the gonadal doses by between 50 and 95%. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses by between 15 and 42% and the gonadal doses by two orders of magnitude.

  1. 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.

  2. 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

  3. Comparison of the standards for absorbed dose to water of the ARPANSA and the BIPM for 60Co γ radiation

    International Nuclear Information System (INIS)

    Allisy-Roberts, P.J.; Burns, D.T.; Boas, J.F.; Huntley, R.B.; Wise, K.N.

    2000-10-01

    A comparison of the standards for absorbed dose to water of the Australian Radiation Protection and Nuclear Safety Agency and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 60 Co gamma radiation. The Australian standard is based on a graphite calorimeter and the subsequent conversion from absorbed dose to graphite to absorbed dose to water using the photon fluence scaling theorem. The BIPM standard is ionometric using a graphite-walled cavity ionization chamber. The comparison result is 1.0024 (standard uncertainty 0.0029). (authors)

  4. Calibration in a manikin of a high dose rate equipment by remote charge

    International Nuclear Information System (INIS)

    Alfonso La Guardia, Rodolfo; Toledo Jimenez, Pablo; Pich Leon, Victor

    1996-01-01

    The aim of this study was to know the immediate results obtained with laparoscopic cholecystectomy in The use of High Dose Rate brachytherapy in Cuba has been limited to AGAT-V Soviet installations. In order to calibrate one of these installations for its clinical use, it was developed a procedure based on the direct measurement of the dose absorbed in referral point B of a paraffin manikin. Results obtained as a result of calibration are shown. According to these results, it was carried out an evaluation of the effective doses administered on prescription point A by using the linear quadratic model

  5. Incase of Same Region Treatment by using a Tomotherapy and a Linear Accelerator Absorbed Dose Evaluation of Normal Tissues and a Tumor

    International Nuclear Information System (INIS)

    Cheon, Geum Seong; Kim, Chang Uk; Kim, Hoi Nam; Heo, Gyeong Hun; Song, Jin Ho; Hong, Joo Yeong; Jeong, Jae Yong

    2010-01-01

    Treating same region with different modalities there is a limit to evaluate the total absorbed dose of normal tissues. The reason is that it does not support to communication each modalities yet. In this article, it evaluates absorbed dose of the patients who had been treated same region by a tomotherapy and a linear accelerator. After reconstructing anatomic structure with a anthropomorphic phantom, administrate 45 Gy to a tumor in linac plan system as well as prescribe 15 Gy in tomotherapy plan system for make an ideal treatment plan. After the plan which made by tomoplan system transfers to the oncentra plan system for reproduce plan under the same condition and realize total treatment plan with summation 45 Gy linac treatment plan. To evaluate the absorbed dose of two different modalities, do a comparative study both a simple summation dose values and integration dose values. Then compare and analyze absorbed dose of normal tissues and a tumor with the patients who had been exposured radiation by above two different modalities. The result of compared data, in case of minimum dose, there are big different dose values in spleen (12.4%). On the other hand, in case of the maximum dose, it reports big different in a small bowel (10.2%) and a cord (5.8%) in head and neck cancer patients, there presents that oral (20.3%), right lens (7.7%) in minimum dose value. About maximum dose, it represents that spinal (22.5), brain stem (12%), optic chiasm (8.9%), Rt lens (11.5%), mandible (8.1%), pituitary gland (6.2%). In case of Rt abdominal cancer patients, there represents big different minimum dose as Lt kidney (20.3%), stomach (8.1%) about pelvic cancer patients, it reports there are big different in minimum dose as a bladder (15.2%) as well as big different value in maximum dose as a small bowel (5.6%), a bladder (5.5%) in addition, making treatment plan it is able us to get. In case of comparing both simple summation absorbed dose and integration absorbed dose, the

  6. The evaluation of lens absorbed dose according to the optimold for whole brain radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong Mo; Park, Byoung Suk; Ahn, Jong Ho; Song, Ki Won [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-06-15

    In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made up to 5 mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. When there was the Optimold mask in the eyeball part, it was measured at 10.2cGy ± 1.5 in the simulation therapy, and at 24.8cGy ± 2.7 in the treatment, and when the Optimold mask was removed in the eye part, it was measured at 12.9cGy ± 2.2 in the simulation therapy, and at 17.6cGy ± 1.5 in the treatment. In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3cGy in the simulation therapy and was reduced approximately 7cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause

  7. The evaluation of lens absorbed dose according to the optimold for whole brain radiation therapy

    International Nuclear Information System (INIS)

    Yang, Yong Mo; Park, Byoung Suk; Ahn, Jong Ho; Song, Ki Won

    2014-01-01

    In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made up to 5 mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. When there was the Optimold mask in the eyeball part, it was measured at 10.2cGy ± 1.5 in the simulation therapy, and at 24.8cGy ± 2.7 in the treatment, and when the Optimold mask was removed in the eye part, it was measured at 12.9cGy ± 2.2 in the simulation therapy, and at 17.6cGy ± 1.5 in the treatment. In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3cGy in the simulation therapy and was reduced approximately 7cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause

  8. Natural radioactivity and dose rates for soil samples around Tiruchirapalli, South India using γ-ray spectrometry

    International Nuclear Information System (INIS)

    Senthilkumar, Bojarajan; Manikandan, Sabapathy; Musthafa, Mohamed Saiyad

    2012-01-01

    The activity concentrations and the gamma-absorbed dose rates of the naturally occurring radionuclides 226 Ra, 232 Th, and 40 K were determined for 40 soil samples collected from Tiruchirapalli, South India, using γ-ray spectrometry. The average activity concentrations of 226 Ra, 232 Th, and 40 K in the soil samples were found to be 29.9, 39.0, and 369.7 Bq kg -1 , respectively. The measured activity concentrations of both 226 Ra and 40 K in the soil were lower than the world average, whereas, the activity of 232 Th was higher than the world average. The concentrations of these radionuclides were also compared with the average activity of the Indian soil. The radiological hazard index was calculated and compared with the internationally approved values. The average external absorbed gamma dose rate was observed to be 79.9 nGy h -1 , with a corresponding average annual effective dose of 97.9 mSv y -1 , which was above the world average values. The values of Ra eq and H ex were found to be within the criterion limit, whereas, the radioactivity level index (l γ ) and total gamma dose rate were above the worldwide average values. (author)

  9. Postoperative vaginal irradiation by a high dose-rate afterloading technique in endometrial carcinoma stage I

    International Nuclear Information System (INIS)

    Sorbe, B.; Smeds, A.C.

    1989-01-01

    A high dose-rate (cobalt-60) afterloading technique was used for postoperative vaginal irradiation in a series of 404 women with endometrial carcinoma stage I. The total recurrence rate was 3.7% with 0.7% vaginal lesions. The crude 5-year survival rate for the complete series was 91.8% compared to 13.3% for those with recurrences. Depth of myometrical infiltration (>1/3 of the uterine wall) and nuclear grade were the most important prognostic factors. Clinically significant late radiation reactions (bladder and/or rectum) were recorded in 6.9%. The absorbed dose per fraction and the size of the treatment volume were significantly related to the occurrence of both early and late radiation reactions. Vaginal shortening was closely related to the dose per fraction, length of the referce isodose and the applicator diameter. The shape of the vaginal applicator versus the isodose contours and the importance of the source train geometry and relative activity for absorbed dose inhomogeneitis within the treatment volume are discussed. Cumulative radiation effect (CRE) and linear-quadratic (LQ) calculations have been performed and related to tissue reactions within the target volume and in the risk organs. An alpha-beta quotient of 8.8 Gy for vaginal shrinkage effect and 2.0 Gy for late rectal complications are suggested on the basis of calculations using a maximum likelihood method for quantal radiation data. (orig.)

  10. A new method for evaluating annual absorbed gamma dose rates in an archaeological site by combining the SSNTD technique with Monte Carlo simulations

    CERN Document Server

    Misdaq, M A; Erramli, H; Mikdad, A; Rzama, A; Yousif-Charif, M L

    1998-01-01

    Uranium and thorium contents in different layers of an archaeological site have been determined by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD) and calculating the probabilities for alpha-particles emitted by the uranium and thorium series to reach and be registered on the SSNTD films. A new method has been developed based on calculating the self-absorption coefficient of the gamma-photons emitted by the uranium ( sup 2 sup 3 sup 8 U), thorium ( sup 2 sup 3 sup 2 Th) and their corresponding decay products as well as the potassium-40 ( sup 4 sup 0 K) isotope for evaluating the annual absorbed gamma dose rates in the considered material samples. Results obtained have been compared with data obtained by using the TL dosimetry and Bell's methods. Ceramic samples belonging to the studied archaeological site have been dated.

  11. Absorbed dose determination in high energy photon beams using new IAEA TRS - 398 Code of Practice

    International Nuclear Information System (INIS)

    Suriyapee, S.; Srimanoroath, S.; Jumpangern, C.

    2002-01-01

    The absorbed dose calibration of 6 and 10 MV X-ray beams from Varian Clinac 1800 at King Chulalongkorn Memorial Hospital Bangkok, Thailand were performed using cylindrical chamber 0.6 cc NE2571 Serial No. 1633 with graphite wall and Delrin build up cap and lonex Dosemaster NE 2590 Serial No. 223. The absorbed dose determination followed the IAEA code of practice TRS-277. The new IAEA code of practice TRS-398 have been studied to compare the result with the IAEA TRS-277

  12. Evaluation of the absorbed dose to the kidneys due to Tc99m (DTPA) / Tc99m (Mag3) and Tc99m (Dmsa)

    International Nuclear Information System (INIS)

    Vasquez A, M.; Murillo C, F.; Castillo D, C.; Rocha J, J.; Sifuentes D, Y.; Sanchez S, P.; Idrogo C, J.; Marquez P, F.

    2015-10-01

    The absorbed dose in the kidneys of adult patients has been assessed using the biokinetics of radiopharmaceuticals containing Tc 99m (DTPA) / Tc 99m (Mag3) or Tc 99m (Dmsa).The absorbed dose was calculated using the formalism MIRD and the Cristy-Eckerman representation for the kidneys. The absorbed dose to the kidneys due to Tc 99m (DTPA) / Tc 99m (Mag3), are given by 0.00466 mGy.MBq -1 / 0.00339 mGy.MBq -1 . Approximately 21.2% of the absorbed dose is due to the bladder (content) and the remaining tissue, included in biokinetics of Tc 99m (DTPA) / Tc 99m (Mag3). The absorbed dose to the kidneys due to Tc 99m (Dmsa) is 0.17881 mGy.MBq -1 . Here, 1.7% of the absorbed dose is due to the bladder, spleen, liver and the remaining tissue, included in biokinetics of Tc 99m (Dmsa). (Author)

  13. Absorbed dose determination in photon fields using the tandem method

    International Nuclear Information System (INIS)

    Marques Pachas, J.F.

    1999-01-01

    The purpose of this work is to develop an alternative method to determine the absorbed dose and effective energy of photons with unknown spectral distributions. It includes a 'tandem' system that consists of two thermoluminescent dosemeters with different energetic dependence. LiF: Mg, Ti, CaF 2 : Dy thermoluminescent dosemeters and a Harshaw 3500 reading system are employed. Dosemeters are characterized with 90 Sr- 90 Y, calibrated with the energy of 60 Co and irradiated with seven different qualities of x-ray beams, suggested by ANSI No. 13 and ISO 4037. The answers of each type of dosemeter are adjusted to a function that depends on the effective energy of photons. The adjustment is carried out by means of the Rosenbrock minimization algorithm. The mathematical model used for this function includes five parameters and has a gauss and a straight line. Results show that the analytical functions reproduce the experimental data of the answers, with a margin of error of less than 5%. The reason of the answers of the CaF 2 : Dy and LiF: Mg, Ti, according to the energy of the radiation, allows us to establish the effective energy of photons and the absorbed dose, with a margin of error of less than 10% and 20% respectively

  14. Quantitative analysis of biological responses to low dose-rate γ-radiation, including dose, irradiation time, and dose-rate

    International Nuclear Information System (INIS)

    Magae, J.; Furukawa, C.; Kawakami, Y.; Hoshi, Y.; Ogata, H.

    2003-01-01

    Full text: Because biological responses to radiation are complex processes dependent on irradiation time as well as total dose, it is necessary to include dose, dose-rate and irradiation time simultaneously to predict the risk of low dose-rate irradiation. In this study, we analyzed quantitative relationship among dose, irradiation time and dose-rate, using chromosomal breakage and proliferation inhibition of human cells. For evaluation of chromosome breakage we assessed micronuclei induced by radiation. U2OS cells, a human osteosarcoma cell line, were exposed to gamma-ray in irradiation room bearing 50,000 Ci 60 Co. After the irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, cytoplasm and nucleus were stained with DAPI and propidium iodide, and the number of binuclear cells bearing micronuclei was determined by fluorescent microscopy. For proliferation inhibition, cells were cultured for 48 h after the irradiation and [3H] thymidine was pulsed for 4 h before harvesting. Dose-rate in the irradiation room was measured with photoluminescence dosimeter. While irradiation time less than 24 h did not affect dose-response curves for both biological responses, they were remarkably attenuated as exposure time increased to more than 7 days. These biological responses were dependent on dose-rate rather than dose when cells were irradiated for 30 days. Moreover, percentage of micronucleus-forming cells cultured continuously for more than 60 days at the constant dose-rate, was gradually decreased in spite of the total dose accumulation. These results suggest that biological responses at low dose-rate, are remarkably affected by exposure time, that they are dependent on dose-rate rather than total dose in the case of long-term irradiation, and that cells are getting resistant to radiation after the continuous irradiation for 2 months. It is necessary to include effect of irradiation time and dose-rate sufficiently to evaluate risk

  15. Calibration of ionization chambers and determination of the absorbed doses

    International Nuclear Information System (INIS)

    RANDRIANTSEHENO, H.F

    1996-01-01

    In order to further improve the accuracy of dosimetric measurements in radiation therapy, the IAEA and WHO supported the establishment of Secondary Standard Dosimetry Laboratory (SSDLs). These SSDLs bridge the gap between the primary measurement standards and the user of ionizing radiation by providing the latter with calibrations against the SSDLs' secondary standards and by giving technical advice and assistance. However, a properly calibrated dosimeter is just necessary first condition for the determination of the dose. It has been demonstrated that the success or failure of radiation treatment depends on the absorbed dose delivered to the tumour and that this should not vary by more than a few per cent from described values. [fr

  16. 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)

  17. Analysis of absorbed dose in cervical spine scanning by computerized tomography using simulator objects

    International Nuclear Information System (INIS)

    Lyra, Maria Henriqueta Freire

    2015-01-01

    The Computed tomography (CT) has become an important diagnostic tool after the continued development of Multidetector CT (MDCT), which allows faster acquisition of images with better quality than the previous technology. However, there is an increased radiation exposure, especially in examinations that require more than one acquisition, as dynamic exams and enhancement studies in order to discriminate low contrast soft tissue injury from normal tissue. Cervical spine MDCT examinations are used for diagnosis of soft tissue and vascular changes, fractures, dysplasia and other diseases with instability, which guide the patient treatment and rehabilitation. This study aims at checking the absorbed dose range in the thyroid and other organs during MDCT scan of cervical spine, with and without bismuth thyroid shield. In this experiment a cervical spine MDCT scan was performed on anthropomorphic phantoms, from the occipital to the first thoracic vertebra, using a 64 and a 16 – channel CT scanners. Thermoluminescent dosimeters were used to obtain the absorbed dose in thyroid, lenses, magnum foramen and breasts of the phantom. The results show that the thyroid received the highest dose, 60.0 mGy, in the female phantom, according to the incidence of the primary X-ray beam. The absorbed doses in these tests showed significant differences in the evaluated organs, p value < 0.005, except for the magnum foramen and breasts. With the bismuth thyroid shield applied on the female phantom, the doses in the thyroid and in the lenses were reduced by 27% and 52%, respectively. On the other hand, a reduction of 23.3% in the thyroid and increasing of 49.0% in the lens were measured on the male phantom. (author)

  18. Pulse and integral optically stimulated luminescence (OSL). Similarities and dissimilarities to thermoluminescence (TL) dose dependence and dose-rate effects

    International Nuclear Information System (INIS)

    Chen, R.; Leung, P.L.

    2000-01-01

    Optically stimulated luminescence (OSL) and thermoluminescence (Tl) are two possible methods to monitor the absorbed radiation in solid samples, and therefore are utilized for dosimetry. For this application, two properties are desirable, namely, linear dose dependence of the measured quantity and dose-rate independence. For Tl, different kinds of super linear dose dependence have been reported in the literature in different materials, and in some cases, dose-rate dependence has also been found. These have been explained as being the result of competition. In OSL, some recent works reported on super linear dose dependence in annealed samples. In the present work, we explain the possible occurrence of these phenomena in OSL by solving numerically the relevant rate equations governing the process during irradiation, relaxation and read-out (heating or light stimulation). The results show that for short pulse OSL, quadratic dose dependence can be expected when only one trapping state and one kind of recombination center are involved and when the excitation starts with empty traps and centers. With the short pulse OSL, the calculation also reveals a possible dose-rate effect. Under the same circumstances, the area under the OSL curve depends linearly on the dose. The dependence of the whole area under the OSL curve on the dose is shown to be super linear when a disconnected trapping state or radiationless center take part in the process. Also, dose-rate effect can be expected in these cases, although no experimental effect of this sort has been reported so far. In pulse OSL, the analogy is made between the measured intensity and the initial rise range of non-first order Tl, whereas for the total area OSL, there is a nearly full analogy with the dose behavior of the Tl maximum. (Author)

  19. Intermediate and fast neutron absorbed doses in fast neutron field at the RB reactor

    International Nuclear Information System (INIS)

    Sokcic-Kostic, M.; Pesic, M.; Antic, D.

    1987-10-01

    The experimental fuel channel EFC is created as one of the fast neutron fields at the RB reactor. The intermediate and fast neutron spectra in EFC are measured by activation technique. The intermediate and fast neutron absorbed doses are computed on the basis of these experimental results. At the end the obtained doses are compared. (author)

  20. Influence of lead apron shielding on absorbed doses from cone-beam computed tomography.

    Science.gov (United States)

    Rottke, Dennis; Andersson, Jonas; Ejima, Ken-Ichiro; Sawada, Kunihiko; Schulze, Dirk

    2017-06-01

    The aim of the present work was to investigate absorbed and to calculate effective doses (EDs) in cone-beam computed tomography (CBCT). The study was conducted using examination protocols with and without lead apron shielding. A full-body male RANDO® phantom was loaded with 110 GR200A thermoluminescence dosemeter chips at 55 different sites and set up in two different CBCT systems (CS 9500®, ProMax® 3D). Two different protocols were performed: the phantom was set up (1) with and (2) without a lead apron. No statistically significant differences in organ and absorbed doses from regions outside the primary beam could be found when comparing results from exposures with and without lead apron shielding. Consequently, calculating the ED showed no significant differences between the examination protocols with and without lead apron shielding. For the ProMax® 3D with shielding, the ED was 149 µSv, and for the examination protocol without shielding 148 µSv (SD = 0.31 µSv). For the CS 9500®, the ED was 88 and 86 µSv (SD = 0.95 µSv), respectively, with and without lead apron shielding. The results revealed no statistically significant differences in the absorbed doses between examination with and without lead apron shielding, especially in organs outside the primary beam. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Absorbed doses profiles vs Synovia tissue depth for the Y-90 and P-32 used in radiosynoviortesis treatment

    International Nuclear Information System (INIS)

    Torres B, M.B.; Ayra P, F.E.; Garcia R, E.; Cornejo D, N.; Yoriyaz, H.

    2006-01-01

    The radiosynoviortesis treatment has been used during more of 40 years as an alternative to the chemical and surgical synovectomy to alleviate the pain and to reduce the inflammation in suffered patients of rheumatic arthropathies, haemophilic arthropathies and other articulation disorders. It consists on the injection of radioactive isotopes inside a synovial cavity. For to evaluate the dosimetry of the radiosynoviortesis treatment is of great interest to know the absorbed dose in the volume of the target (synovia). The precise calculation of the absorbed dose in the inflamed synovia it is difficult, for numerous reasons, since the same one will depend on the thickness of the synovial membrane, the size of the articular space, the structure of the synovial membrane, the distribution in the articulation, the nature of the articular liquid, etc. Also the presence of the bone and the articular cartilage, components also of the articulation, it even complicated more the calculations. The method used to evaluate the dosimetry in radioactive synovectomy is known as the Monte Carlo method. The objective of our work consists on estimating with the Monte Carlo code MCNP4B the absorbed dose of the Y-90 and the P-32 in the depth of the synovial tissue. The results are presented as absorbed dose for injected millicurie (Gy/mCi) versus depth of synovial tissue. The simulation one carries out keeping in mind several synovia areas, of 50 cm 2 to 250 cm 2 keeping in mind three states of progression of the illness. Those obtained values of absorbed dose using the MCNP4B code will allow to introduce in our country an optimized method of dose prescription to the patient, to treat the rheumatic arthritis in medium and big articulations using the Y-90 and the P-32, eliminating the fixed doses and fixed radionuclides for each articulation like it happens in many clinics of Europe, as well as the empiric doses. (Author)

  2. Sci-Sat AM: Brachy - 03: Feasibility study of the determination of absorbed dose to water using a fricke based system.

    Science.gov (United States)

    Gamal, I El; Cojocaru, C; Ross, C; Marchington, D; McEwen, M

    2012-07-01

    By measuring the dose to water directly a metrology standard, independent of air kerma, can be developed to make the basis of HDR brachytherapy dosimetry consistent with current dosimetry methods for external radiation beams. The Fricke dosimeter system, a liquid chemical dosimeter, provides a means of measuring the absorbed dose rate to water directly by measuring the radiation-induced change in absorption of the Fricke solution. In an attempt to measure the absorbed dose to water directly for a 192 Ir HDR brachytherapy source a ring shaped Fricke holder was constructed from PMMA, essentially following the work of Austerlitz et al. (Med. Phys. 2008). Benchmark measurements conducted in a 60 Co beam yielded a standard uncertainty in the absorption reading of 0.16 %, comparable with previous results in the literature. Measurements of the standard uncertainty of the control (unirradiated) solution using the holder yielded 0.2 %, indicating good process control and minimal contamination from the holder itself. However, it was found that the holder sealing method (to allow measurements in a water phantom) significantly contaminated the Fricke solution, resulting in an excessive background reading. Irradiations were therefore conducted in air to determine the feasibility of the procedure. Irradiations with a 17 GBq source gave a standard uncertainty of approximately 0.5 %, indicating that the target uncertainty of 1.5% for the measurement of absorbed dose to water using a Fricke-based primary standard is achievable. This would be comparable with calorimeter-based systems currently being developed. © 2012 American Association of Physicists in Medicine.

  3. Preliminary survey of absorbed dose rates in air at Guarapari and Meaipe in Brazil

    International Nuclear Information System (INIS)

    Fujinami, Naoto; Koga, Taeko; Morishima, Hiroshige

    1999-01-01

    A preliminary survey of the gamma-ray exposure rate was carried out at Guarapari and Meaipe in Brazil in September 1998. In those areas, exposure rates in the streets ranged from 0.1 to 0.4 μGy/h except for a few places such as near the beaches. Exposure rates inside houses were lower than 0.2 μGy/h except for two houses where an exposure rate of 0.4 μGy/h was measured. Our effective dose rate from external terrestrial irradiation was 0.17 μSv/h on the average during the period of our three-day stay in Guarapari (outdoors and indoors). These values are lower than those observed in the 1960s, which were cited in UNSCEAR reports. This fact suggests that the natural radiation environment of Guarapari has varied with urbanization, which brought paved streets, and changes in the structure and building materials of houses. A detailed survey is necessary in order to evaluate the present exposure rates in these areas. (author)

  4. Regression models in the determination of the absorbed dose with extrapolation chamber for ophthalmological applicators

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Morales P, R.

    1992-06-01

    The absorbed dose for equivalent soft tissue is determined,it is imparted by ophthalmologic applicators, ( 90 Sr/ 90 Y, 1850 MBq) using an extrapolation chamber of variable electrodes; when estimating the slope of the extrapolation curve using a simple lineal regression model is observed that the dose values are underestimated from 17.7 percent up to a 20.4 percent in relation to the estimate of this dose by means of a regression model polynomial two grade, at the same time are observed an improvement in the standard error for the quadratic model until in 50%. Finally the global uncertainty of the dose is presented, taking into account the reproducibility of the experimental arrangement. As conclusion it can infers that in experimental arrangements where the source is to contact with the extrapolation chamber, it was recommended to substitute the lineal regression model by the quadratic regression model, in the determination of the slope of the extrapolation curve, for more exact and accurate measurements of the absorbed dose. (Author)

  5. Emission properties of thermoluminescence from natural quartz - blue and red TL response to absorbed dose

    International Nuclear Information System (INIS)

    Hashimoto, T.; Yokosaka, K.; Habuki, H.

    1987-01-01

    The TL spectrometry of natural quartz exposed to a gamma radiation dose of 8.8 kGy proved that the red TL, mainly from volcanically originated quartz, has a broad emission band with a peak around 620 nm, while the blue TL from plutonically originated quartz also has a broad emission band giving a peak around 470 nm. These typical red or blue intrinsic colours were also confirmed on the thermoluminescence colour images (TLCI). Exceptionally, a pegmatite quartz changed its TLCI colour from red to blue when the absorbed dose was increased. By using colour filter assemblies, all these quartz samples were shown to emit mainly blue and red TLs, which have distinctly different TL responses to the absorbed dose; the blue invariably showed a supralinearity relation between 1 and 10 kGy dose. For the purpose of dating, the use of red TL, is preferable. The red TL component is related to the impurity Eu content in quartz minerals. (author)

  6. Influence of dose rate of ionizing radiation on working capacity of the oil-filled electrical equipment for NPP; Vliyanie moshchnosti dozy ioniziruyushchego oblucheniya na rabotosposobnost` maslonapolnennogo ehlektrooborudovaniya dlya AEhS

    Energy Technology Data Exchange (ETDEWEB)

    Tyutnev, A P [and others

    1994-12-31

    Dependence of radiation electric conductivity transformer oil on the gamma radiation absorbed dose rate and on the energy proton flux is investigated. It is ascertained that the electrical reliability of oil and oil-barrier insulation does not depend on the absorbed dose rate up to the maximum achieved values of 200 rad/s.

  7. Dose rates from a C-14 source using extrapolation chamber and MC calculations

    International Nuclear Information System (INIS)

    Borg, J.

    1996-05-01

    The extrapolation chamber technique and the Monte Carlo (MC) calculation technique based on the EGS4 system have been studied for application for determination of dose rates in a low-energy β radiation field e.g., that from a 14 C source. The extrapolation chamber measurement method is the basic method for determination of dose rates in β radiation fields. Applying a number of correction factors and the stopping power ratio, tissue to air, the measured dose rate in an air volume surrounded by tissue equivalent material is converted into dose to tissue. Various details of the extrapolation chamber measurement method and evaluation procedure have been studied and further developed, and a complete procedure for the experimental determination of dose rates from a 14 C source is presented. A number of correction factors and other parameters used in the evaluation procedure for the measured data have been obtained by MC calculations. The whole extrapolation chamber measurement procedure was simulated using the MC method. The measured dose rates showed an increasing deviation from the MC calculated dose rates as the absorber thickness increased. This indicates that the EGS4 code may have some limitations for transport of very low-energy electrons. i.e., electrons with estimated energies less than 10 - 20 keV. MC calculations of dose to tissue were performed using two models: a cylindrical tissue phantom and a computer model of the extrapolation chamber. The dose to tissue in the extrapolation chamber model showed an additional buildup dose compared to the dose in the tissue model. (au) 10 tabs., 11 ills., 18 refs

  8. Absorbed radiation doses in women undergone to PET-CT exams for cancer diagnosis

    International Nuclear Information System (INIS)

    Santana, Priscila do Carmo; Bernardes, Felipe Dias; Mamede, Marcelo; Oliveira, Paulo Marcio Campos de; Silva, Teogenes Augusto da; Mourao FIlho, Arnaldo Prata

    2014-01-01

    The absorbed dose in several organs and the effective dose in patients submitted to PET-CT exams with the radiopharmaceutical 18 F-FDG were assessed. The ICRP-106 biokinetic model and thermoluminescent detectors in a anthropomorphic phantom were used. The use of the PET-CT image acquisition protocol, with the CT protocol for anatomical mapping, showed that 60% of effective dose was from the radiotracer administration, being the effective dose values for a female patient of (5.80 ± 1.57) mSv. In conclusion, patient doses can be reduced by using appropriate imaging acquisition in 18 F-FDG PET-CT examinations and promoting the compliance with the radiation protection principles. (author)

  9. Study on the quality assurance of diagnostic X-ray machines and assessment of the absorbed dose to patients

    Science.gov (United States)

    Hassan, G. M.; Rabie, N.; Mustafa, K. A.; Abdel-Khalik, S. S.

    2012-09-01

    Radiation exposure and image quality in X-ray diagnostic radiology provide a clear understanding of the relationship between the radiation dose delivered to a patient and image quality in optimizing medical diagnostic radiology. Because a certain amount of radiation is unavoidably delivered to patients, this should be as low as reasonably achievable. Several X-ray diagnostic machines were used at different medical diagnostic centers in Egypt for studying the beam quality and the dose delivered to the patient. This article studies the factors affecting the beam quality, such as the kilo-volt peak (kVp), exposure time (mSc), tube current (mAs) and the absorbed dose in (μGy) for different examinations. The maximum absorbed dose measured per mAs was 594±239 and 12.5±3.7 μGy for the abdomen and the chest, respectively, while the absorbed dose at the elbow was 18±6 μGy, which was the minimum dose recorded. The compound and expanded uncertainties accompanying these measurements were 4±0.35% and 8±0.7%, respectively. The measurements were done through quality control tests as acceptance procedures.

  10. Radionuclide content in some building materials and gamma dose rate in dwellings in Cuba

    International Nuclear Information System (INIS)

    Brigido, Oslvaldo; Montalvan, Adelmo; Rosa, Ramon; Hernandez, Alberto

    2008-01-01

    Naturally occurring radionuclides in building materials are one of the sources of radiation exposure of the population. This study was undertaken with the purpose of determining radioactivity in some Cuban building materials and for assessing the annual effective dose to Cuban population due external gamma exposure in dwellings for typical Cuban room model. Forty four samples of raw materials and building products were collected in some Cuban provinces. The activity concentrations of natural radionuclides were determined by gamma ray spectrometry using a p-type coaxial high purity germanium detector and their mean values are in the ranges: 9 to 857 Bq.kg -1 for 40 K; 6 to 57 Bq.kg -1 for 226 Ra; and 1.2 to 22 Bq.kg -1 for 232 Th. The radium equivalent activity in the 44 samples varied from 4 Bq.kg -1 (wood) to 272 Bq.kg -1 (brick). A high pressure ionisation chamber was used for measuring of the indoor absorbed dose rate in 543 dwellings and workplaces in five Cuban provinces. The average absorbed dose rates in air ranged from 43 n Gy.h -1 (Holguin) to 73 n Gy.h -1 (Camaguey) and the corresponding population-weighted annual effective dose due to terrestrial gamma radiation was estimated to be 145 ± 40 μSv. This dose value is 16% higher than the calculated value for typical room geometry of Cuban house. (author)

  11. Radiobiological aspects of continuous low dose-rate irradiation and fractionated high dose-rate irradiation

    International Nuclear Information System (INIS)

    Turesson, I.

    1990-01-01

    The biological effects of continuous low dose-rate irradiation and fractionated high dose-rate irradiation in interstitial and intracavitary radiotherapy and total body irradiation are discussed in terms of dose-rate fractionation sensitivity for various tissues. A scaling between dose-rate and fraction size was established for acute and late normal-tissue effects which can serve as a guideline for local treatment in the range of dose rates between 0.02 and 0.005 Gy/min and fraction sizes between 8.5 and 2.5 Gy. This is valid provided cell-cycle progression and proliferation can be ignored. Assuming that the acute and late tissue responses are characterized by α/β values of about 10 and 3 Gy and a mono-exponential repair half-time of about 3 h, the same total doses given with either of the two methods are approximately equivalent. The equivalence for acute and late non-hemopoietic normal tissue damage is 0.02 Gy/min and 8.5 Gy per fraction; 0.01 Gy/min and 5.5 Gy per fraction; and 0.005 Gy/min and 2.5Gy per fraction. A very low dose rate, below 0.005 Gy/min, is thus necessary to simulate high dose-rate radiotherapy with fraction sizes of about 2Gy. The scaling factor is, however, dependent on the repair half-time of the tissue. A review of published data on dose-rate effects for normal tissue response showed a significantly stronger dose-rate dependence for late than for acute effects below 0.02 Gy/min. There was no significant difference in dose-rate dependence between various acute non-hemopoietic effects or between various late effects. The consistent dose-rate dependence, which justifies the use of a general scaling factor between fraction size and dose rate, contrasts with the wide range of values for repair half-time calculated for various normal-tissue effects. This indicates that the model currently used for repair kinetics is not satisfactory. There are also few experimental data in the clinical dose-rate range, below 0.02 Gy/min. It is therefore

  12. Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

    Directory of Open Access Journals (Sweden)

    Gh Bagheri

    2011-09-01

    Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.

  13. External Auditing on Absorbed Dose Using a Solid Water Phantom for Domestic Radiotherapy Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Heon; Kim, Jung In; Park, Jong Min; Park, Yang Kyun; Ye, Sung Joon [Medical Research Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cho, Kun Woo; Cho, Woon Kap [Radiation Research, Korean Institute of Nuclear Safety, Daejeon (Korea, Republic of); Lim, Chun Il [Korea Food and Drug Administration, Seoul (Korea, Republic of)

    2010-11-15

    We report the results of an external audit on the absorbed dose of radiotherapy beams independently performed by third parties. For this effort, we developed a method to measure the absorbed dose to water in an easy and convenient setup of solid water phantom. In 2008, 12 radiotherapy centers voluntarily participated in the external auditing program and 47 beams of X-ray and electron were independently calibrated by the third party's American Association of Physicists in Medicine (AAPM) task group (TG)-51 protocol. Even though the AAPM TG-51 protocol recommended the use of water, water as a phantom has a few disadvantages, especially in a busy clinic. Instead, we used solid water phantom due to its reproducibility and convenience in terms of setup and transport. Dose conversion factors between solid water and water were determined for photon and electron beams of various energies by using a scaling method and experimental measurements. Most of the beams (74%) were within {+-}2% of the deviation from the third party's protocol. However, two of 20 X-ray beams and three of 27 electron beams were out of the tolerance ({+-}3%), including two beams with a >10% deviation. X-ray beams of higher than 6 MV had no conversion factors, while a 6 MV absorbed dose to a solid water phantom was 0.4% less than the dose to water. The electron dose conversion factors between the solid water phantom and water were determined: The higher the electron energy, the less is the conversion factor. The total uncertainty of the TG-51 protocol measurement using a solid water phantom was determined to be {+-}1.5%. The developed method was successfully applied for the external auditing program, which could be evolved into a credential program of multi-institutional clinical trials. This dosimetry saved time for measuring doses as well as decreased the uncertainty of measurement possibly resulting from the reference setup in water.

  14. Development of fluorescent, oscillometric and photometric methods to determine absorbed dose in irradiated fruits and nuts

    International Nuclear Information System (INIS)

    Kovacs, A.; Foeldiak, G.; Hargittai, P.; Miller, S.D.

    2001-01-01

    To ensure suitable quality control at food irradiation technologies and for quarantine authorities, simple routine dosimetry methods are needed for absorbed dose control. Taking into account the requirements at quarantine locations these methods would require nondestructive analysis for repeated measurements. Different dosimetry systems with different analytical evaluation methods have been tested and/or developed for absorbed dose measurements in the dose range of 0.1-10 kGy. In order to use the well accepted ethanolmonochlorobenzene dosimeter solution and the recently developed aqueous alanine solution in small volume sealed vials, a new portable, digital, and programmable oscillometric reader was developed. To make use of the availability of the very sensitive fluorimetric evaluation method, liquid and solid inorganic and organic dosimetry systems were developed for dose control using a new routine, portable, and computer controlled fluorimeter. Absorption or transmission photometric methods were also applied for dose measurements of solid or liquid phase dosimeter systems containing radiochromic dye agents, which change colour upon irradiation. (author)

  15. Aerial gamma spectrometry of the uranium province of Lagoa Real (Caetite, BA, Brazil): go environmental aspects and distribution of the absorbed dose in the air

    International Nuclear Information System (INIS)

    Santos, Esau Francisco Sena

    2006-01-01

    In the present study, it was analyzed the surface concentrations of the natural radioelements K, U and Th, as well as the absorbed dose rate in air caused by gamma radiation from the Lagoa Real uranium province, which is located at the center southern portion of Bahia State and comprises an area of approximately 4.600 Km 2 . Data from the airborne gamma ray spectrometric survey of the region (Sao Timoeo Project) carried out in 1979, was used in this study. Besides, recent data of U, Th and absorbed dose rates from the Environmental Monitoring Program of the uranium concentration plant (URA), operated in the region by the Brazilian Nuclear Industries (INB), were used with the aim of inter compare the sampling points in the same geo referenced area. Imaging geo processing software's give support to frame maps of surface concentrations and ternary maps, as well as allow the integration of these with other themes (e.g. hydrology, geology, pedology) favouring the interpretation of geo environmental process from the radioactive cartography. Considering the whole study area, it was obtained the following mean values: absorbed dose rate in air (61,08 nGy.h -1 ), Potassium (1,65 % K) , Uranium (3,02 ppm eU) and thorium (18,26 ppm eTh). The geological unities bounding the uranium anomalies were placed in the areas characterized by the highest values of radioelements and, as expected, the major dose levels. The use of ternary maps coupled with the geology and hydrology allowed distinguishing the relationship between the surface distribution of natural radioelements and the geo environmental aspects, including the influence of the catchment in their transport and migration. (author)

  16. Measurement of absorbed dose for high energy electron using CaSO4: Tm-PTFE TLD

    International Nuclear Information System (INIS)

    Park, Myeong Hwan; Kim, Do Sung

    2000-01-01

    In this study, the highly sensitive CaSO 4 : Tm-PTFE TLDs has been fabricated for the purpose of measurement of high energy electron. CaSO 4 : Tm phosphor powder was mixed with polytetrafluoroethylene(PTFE) powder and moulded in a disk type(diameter 8.5mm, thickness 90mg/cm 2 ) by cold pressing. The absorbed dose distribution and ranges for high energy electron were measured by using the CaSO 4 : Tm-PTFE TLDs. The ranges determined were R 100 =3D14.5mm, R 50 =3D24.1mm and R p =3D31.8mm, respectively and the beam flatness, the variation of relative dose in 80% of the field size, was 4.5%. The fabricated CaSO 4 : Tm-PTFE TLDs may be utilized in radiation dosimetry for personal, absorbed dose and environmental monitoring.=20

  17. Uncertainty analysis in the determination of absorbed dose in water by Fricke chemical dosimetry; Analise das incertezas na determinacao da dose absorvida na agua por dosimetria quimica Fricke

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Fabia; Aguirre, Eder Aguirre, E-mail: fabiavasco@hotmail.com, E-mail: ederuni01@gmail.com [Fundacao do Cancer, Rio de Janeiro, RJ (Brazil); Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2016-07-01

    This work studies the calculations of uncertainties and the level of confidence that involves the process for obtaining the dose absorbed in water using the method of Fricke dosimetry, developed at Laboratorio de Ciencias Radiologicas (LCR). Measurements of absorbance of samples Fricke, irradiated and non-irradiated is going to use in order to calculate the respective sensitivity coefficients, along with the expressions of the calculation of Fricke dose and the absorbed dose in water. Those expressions are used for calculating the others sensitivity coefficients from the input variable. It is going to use the combined uncertainty and the expanded uncertainty, with a level of confidence of 95.45%, in order to report the uncertainties of the measurement. (author)

  18. The absorbed dose to the blood is a better predictor of ablation success than the administered {sup 131}I activity in thyroid cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Verburg, Frederik A.; Lassmann, Michael; Reiners, Christoph; Haenscheid, Heribert [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Maeder, Uwe [University of Wuerzburg, Comprehensive Cancer Center Mainfranken, Wuerzburg (Germany); Luster, Markus [University of Ulm, Department of Nuclear Medicine, Ulm (Germany)

    2011-04-15

    The residence time of {sup 131}I in the blood is likely to be a measure of the amount of {sup 131}I that is available for uptake by thyroid remnant tissue and thus the radiation absorbed dose to the target tissue in {sup 131}I ablation of patients with differentiated thyroid cancer (DTC). This hypothesis was tested in an investigation on the dependence of the success rate of radioiodine remnant ablation on the radiation absorbed dose to the blood (BD) as a surrogate for the amount of {sup 131}I available for iodine-avid tissue uptake. This retrospective study included 449 DTC patients who received post-operative {sup 131}I ablation in our centre in the period from 1993 to 2007 and who returned to us for diagnostic whole-body scintigraphy. The BD was calculated based on external dose rate measurements using gamma probes positioned in the ceiling. Success of ablation was defined as a negative diagnostic {sup 131}I whole-body scan and undetectable thyroglobulin levels at 6 months follow-up. Ablation was successful in 56.6% of the patients. The rate of successful ablation correlated significantly with BD but not with the administered activity. Patients with blood doses exceeding 350 mGy (n = 144) had a significantly higher probability for successful ablation (63.9%) than the others (n = 305, ablation rate 53.1%, p = 0.03). In contrast, no significant dependence of the ablation rate on the administered activity was observed. The BD is a more powerful predictor of ablation success than the administered activity. (orig.)

  19. A study of microscopic dose rate distribution of 99Tcm-MIBI in the liver of mice

    International Nuclear Information System (INIS)

    Wang Mingxi; Zhang Liang'an; Wang Yong; Dai Guangfu

    2002-01-01

    Objective: A microdosimetry model was tried to develop an accurate way to evaluate absorbed dose rates in target cell nuclei from radiopharmaceuticals. Methods: Microscopic frozen section autoradiography was used to determine the subcellular locations of 99 Tc m -MIBI relative to the tissue histology in the liver of mice after injection of 99 Tc m -MIBI via tail for two hours, and a mathematical model was developed to evaluate the microscopic dose rates in cell nuclei. The Medical Internal Radiation Dose (MIRD) schema was also used to evaluate the dose rates at the same time, and a comparison of the results of the two methods was conducted to determine which method is better to accurately estimate microscopic dose rates. Results: The spatial distribution of 99 Tc m -MIBI in the liver of mice at subcellular level was not uniform, and the differences between the microdosimetry model and MIRD schema were significant (P 99 Tc m -labeled pharmaceuticals at the microscopic level

  20. Absorbed dose distributions in patients with bone metastases from hormone refractory prostate cancer treated with Re-186 HEDP

    International Nuclear Information System (INIS)

    Denis Bacelar, A.M.; Dearnaley, D.P.; Divoli, A.; Chittenden, S.; Du, Y.; Flux, G.D.; O'Sullivan, J.M.

    2015-01-01

    Full text of publication follows. Aim: intravenous administration of Re-186 hydroxyethylidene-diphosphonate (HEDP) is used for metastatic bone pain palliation in hormone refractory prostate cancer patients. Dosimetry for bone seeking radionuclides is challenging due to the complex structure with osteoblastic, osteolytic and mixed lesions. The aim of this study was to perform image-based patient-specific 3D convolution dosimetry to obtain a distribution of the absorbed doses to each lesion and estimate inter- and intra-patient variations. Materials and methods: 28 patients received a fixed 5 GBq activity of Re-186 HEDP followed by peripheral blood stem cell rescue at 14 days in a phase II trial. A FORTE dual-headed gamma camera was used to acquire sequential Single-Photon-Emission Computed Tomography (SPECT) data of the thorax and pelvis area at 1, 4, 24, 48 and 72 hours following administration. The projection data were reconstructed using filtered-back projection and were corrected for attenuation and scatter. Voxelised cumulated activity distributions were obtained with two different methods. First, the scans were co-registered and the time-activity curves were obtained on a voxel-by-voxel basis. Second, the clearance curve was obtained from the mean number of counts in each individual lesion and used to scale the uptake distribution taken at 24 hours. The calibration factors required for image quantification were obtained from a phantom experiment. An in-house developed EGSnrc Monte Carlo code was used for the calculation of dose voxel kernels for soft-tissue and cortical/trabecular bone used to perform convolution dosimetry. Cumulative dose-volume histograms were produced and mean absorbed doses calculated for each spinal and pelvic lesion. Results: preliminary results show that the lesion mean absorbed doses ranged from 25 to 55 Gy when the medium was soft tissue and decreased by 40% if bone was considered. The use of the cumulated activity distribution

  1. Dose rate evaluation of body phantom behind ITER bio-shield wall using Monte Carlo method

    International Nuclear Information System (INIS)

    Beheshti, A.; Jabbari, I.; Karimian, A.; Abdi, M.

    2012-01-01

    One of the most critical risks to humans in reactors environment is radiation exposure. Around the tokamak hall personnel are exposed to a wide range of particles, including neutrons and photons. International Thermonuclear Experimental Reactor (ITER) is a nuclear fusion research and engineering project, which is the most advanced experimental tokamak nuclear fusion reactor. Dose rates assessment and photon radiation due to the neutron activation of the solid structures in ITER is important from the radiological point of view. Therefore, the dosimetry considered in this case is based on the Deuterium-Tritium (DT) plasma burning with neutrons production rate at 14.1 MeV. The aim of this study is assessment the amount of radiation behind bio-shield wall that a human received during normal operation of ITER by considering neutron activation and delay gammas. To achieve the aim, the ITER system and its components were simulated by Monte Carlo method. Also to increase the accuracy and precision of the absorbed dose assessment a body phantom were considered in the simulation. The results of this research showed that total dose rates level near the outside of bio-shield wall of the tokamak hall is less than ten percent of the annual occupational dose limits during normal operation of ITER and It is possible to learn how long human beings can remain in that environment before the body absorbs dangerous levels of radiation. (authors)

  2. Image quality and absorbed dose comparison of single- and dual-source cone-beam computed tomography.

    Science.gov (United States)

    Miura, Hideharu; Ozawa, Shuichi; Okazue, Toshiya; Kawakubo, Atsushi; Yamada, Kiyoshi; Nagata, Yasushi

    2018-04-17

    Dual-source cone-beam computed tomography (DCBCT) is currently available in the Vero4DRT image-guided radiotherapy system. We evaluated the image quality and absorbed dose for DCBCT and compared the values with those for single-source CBCT (SCBCT). Image uniformity, Hounsfield unit (HU) linearity, image contrast, and spatial resolution were evaluated using a Catphan phantom. The rotation angle for acquiring SCBCT and DCBCT images is 215° and 115°, respectively. The image uniformity was calculated using measurements obtained at the center and four peripheral positions. The HUs of seven materials inserted into the phantom were measured to evaluate HU linearity and image contrast. The Catphan phantom was scanned with a conventional CT scanner to measure the reference HU for each material. The spatial resolution was calculated using high-resolution pattern modules. Image quality was analyzed using ImageJ software ver. 1.49. The absorbed dose was measured using a 0.6-cm 3 ionization chamber with a 16-cm-diameter cylindrical phantom, at the center and four peripheral positions of the phantom, and calculated using weighted cone-beam CT dose index (CBCTDI w ). Compared with that of SCBCT, the image uniformity of DCBCT was slightly reduced. A strong linear correlation existed between the measured HU for DCBCT and the reference HU, although the linear regression slope was different from that of the reference HU. DCBCT had poorer image contrast than did SCBCT, particularly with a high-contrast material. There was no significant difference between the spatial resolutions of SCBCT and DCBCT. The absorbed dose for DCBCT was higher than that for SCBCT, because in DCBCT, the two x-ray projections overlap between 45° and 70°. We found that the image quality was poorer and the absorbed dose was higher for DCBCT than for SCBCT in the Vero4DRT. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of

  3. Monte Carlo Estimation of Absorbed Dose Distributions Obtained from Heterogeneous 106Ru Eye Plaques.

    Science.gov (United States)

    Zaragoza, Francisco J; Eichmann, Marion; Flühs, Dirk; Sauerwein, Wolfgang; Brualla, Lorenzo

    2017-09-01

    The distribution of the emitter substance in 106 Ru eye plaques is usually assumed to be homogeneous for treatment planning purposes. However, this distribution is never homogeneous, and it widely differs from plaque to plaque due to manufacturing factors. By Monte Carlo simulation of radiation transport, we study the absorbed dose distribution obtained from the specific CCA1364 and CCB1256 106 Ru plaques, whose actual emitter distributions were measured. The idealized, homogeneous CCA and CCB plaques are also simulated. The largest discrepancy in depth dose distribution observed between the heterogeneous and the homogeneous plaques was 7.9 and 23.7% for the CCA and CCB plaques, respectively. In terms of isodose lines, the line referring to 100% of the reference dose penetrates 0.2 and 1.8 mm deeper in the case of heterogeneous CCA and CCB plaques, respectively, with respect to the homogeneous counterpart. The observed differences in absorbed dose distributions obtained from heterogeneous and homogeneous plaques are clinically irrelevant if the plaques are used with a lateral safety margin of at least 2 mm. However, these differences may be relevant if the plaques are used in eccentric positioning.

  4. Absorbed dose due to radioiodine therapy by organs of patients with hyperthyroidism

    International Nuclear Information System (INIS)

    Lima, F.F.; Khoury, H.J.; Bertelli Neto, L.; Bertelli Neto, L.

    1999-01-01

    The dose absorbed by organs of patients with hyperthyroidism treated with 131 I was estimated by using the MIRDOSE computer program and data from ICRP-53. The calculation were performed using effective half-life and uptake average values, which were determined for 17 patients treated with 370 MBq and 555MBq of 131 I. The results shown that the dose in the thyroid, for a 370 MBq administrated activity, was of 99 Gy and 49.5 Gy for 60 g and 80 g thyroid respectively. The average dose estimated in other organs were relatively low, presenting values lower than 0.1 Gy in the kidneys, bone marrow and ovaries and 0.19 Gy in the stomach

  5. Absorbed-dose beam quality conversion factors for cylindrical chambers in high energy photon beams.

    Science.gov (United States)

    Seuntjens, J P; Ross, C K; Shortt, K R; Rogers, D W

    2000-12-01

    Recent working groups of the AAPM [Almond et al., Med. Phys. 26, 1847 (1999)] and the IAEA (Andreo et al., Draft V.7 of "An International Code of Practice for Dosimetry based on Standards of Absorbed Dose to Water," IAEA, 2000) have described guidelines to base reference dosimetry of high energy photon beams on absorbed dose to water standards. In these protocols use is made of the absorbed-dose beam quality conversion factor, kQ which scales an absorbed-dose calibration factor at the reference quality 60Co to a quality Q, and which is calculated based on state-of-the-art ion chamber theory and data. In this paper we present the measurement and analysis of beam quality conversion factors kQ for cylindrical chambers in high-energy photon beams. At least three chambers of six different types were calibrated against the Canadian primary standard for absorbed dose based on a sealed water calorimeter at 60Co [TPR10(20)=0.572, %dd(10)x=58.4], 10 MV [TPR10(20)=0.682, %dd(10)x=69.6), 20 MV (TPR10(20)=0.758, %dd(10)x= 80.5] and 30 MV [TPR10(20) = 0.794, %dd(10)x= 88.4]. The uncertainty on the calorimetric determination of kQ for a single chamber is typically 0.36% and the overall 1sigma uncertainty on a set of chambers of the same type is typically 0.45%. The maximum deviation between a measured kQ and the TG-51 protocol value is 0.8%. The overall rms deviation between measurement and the TG-51 values, based on 20 chambers at the three energies, is 0.41%. When the effect of a 1 mm PMMA waterproofing sleeve is taken into account in the calculations, the maximum deviation is 1.1% and the overall rms deviation between measurement and calculation 0.48%. When the beam is specified using TPR10(20), and measurements are compared with kQ values calculated using the version of TG-21 with corrected formalism and data, differences are up to 1.6% when no sleeve corrections are taken into account. For the NE2571 and the NE2611A chamber types, for which the most literature data are

  6. ESR spectroscopy for detecting gamma-irradiated dried vegetables and estimating absorbed doses

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Joong-Ho; Chung, Hyung-Wook; Byun, Myung-Woo

    2000-03-01

    In view of an increasing demand for food irradiation technology, the development of a reliable means of detection for the control of irradiated foods has become necessary. Various vegetable food materials (dried cabbage, carrot, chunggyungchae, garlic, onion, and green onion), which can be legally irradiated in Korea, were subjected to a detection study using ESR spectroscopy. Correlation coefficients (R{sup 2}) between absorbed doses (2.5-15 kGy) and their corresponding ESR signals were identified from ESR signals. Pre-established threshold values were successfully applied to the detection of 54 coded unknown samples of dried clean vegetables (chunggyungchae, Brassica camestris var. chinensis), both non-irradiated and irradiated. The ESR signals of irradiated chunggyungchae decreased over a longer storage time, however, even after 6 months of ambient storage, these signals were still distinguishable from those of non-irradiated samples. The most successful estimates of absorbed dose (5 and 8 kGy) were obtained immediately after irradiation using a quadratic fit with average values of 4.85 and 8.65 kGy being calculated. (author)

  7. Thoron exhalation rate monitor with absorber

    International Nuclear Information System (INIS)

    Xiao Detao; Zhao Guizhi

    2003-01-01

    A measurement method of thoron exhalation rate is developed based on the characteristic of thorium C' which emits a α particle with higher energy than those of α particles released from radon and radon progenies. The principles of discriminating radon and realizing thoron exhalation rate measurement on the material surface with absorber, the passive and integrated thoron exhalation rate monitor studied, and its calibration coefficient determination method are introduced. The effectiveness of mitigating thoron exhalation rate of wall surface by depressurization inside wall and thoron exhalation rates on some materials surfaces were measured by using the studied monitors. The calibration coefficient of the studied monitor is R=0.246 cm -2 ·(kBq·m -3 ·h) -1 . The lower limit of detection is LLD=18.4 mBq·m -2 ·s -1 when the sampling period is 7 days and the standard deviation of background track densities of the adopted CR-39 SSNTD is s T =1.6 cm -2

  8. Relative implications of protective responses versus damage induction at low dose and low-dose-rate exposures, using the microdose approach

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E

    2003-07-01

    In reviewing tissue effects of low-dose radiation (1) absorbed dose to tissue is replaced by the sum of energy deposited with track events in cell-equivalent tissue micromasses, i.e. with microdose hits, in the number of exposed micromasses and (2) induced cell damage and adaptive protection are related to microdose hits in exposed micromasses for a given radiation quality. DNA damage increases with the number of microdose hits. They also can induce adaptive protection, mainly against endogenous DNA damage. This protection involves cellular defenses, DNA repair and damage removal. With increasing numbers of low linear energy transfer (LET) microdose hits in exposed micromasses, adaptive protection first tends to outweigh damage and then (above 200 mGy) fails and largely disappears. These experimental data predict that cancer risk coefficients derived by epidemiology at high-dose irradiation decline at low doses and dose rates when adaptive protection outdoes DNA damage. The dose-risk function should include both linear and non-linear terms at low doses. (author)

  9. Relative implications of protective responses versus damage induction at low dose and low-dose-rate exposures, using the microdose approach

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    2003-01-01

    In reviewing tissue effects of low-dose radiation (1) absorbed dose to tissue is replaced by the sum of energy deposited with track events in cell-equivalent tissue micromasses, i.e. with microdose hits, in the number of exposed micromasses and (2) induced cell damage and adaptive protection are related to microdose hits in exposed micromasses for a given radiation quality. DNA damage increases with the number of microdose hits. They also can induce adaptive protection, mainly against endogenous DNA damage. This protection involves cellular defenses, DNA repair and damage removal. With increasing numbers of low linear energy transfer (LET) microdose hits in exposed micromasses, adaptive protection first tends to outweigh damage and then (above 200 mGy) fails and largely disappears. These experimental data predict that cancer risk coefficients derived by epidemiology at high-dose irradiation decline at low doses and dose rates when adaptive protection outdoes DNA damage. The dose-risk function should include both linear and non-linear terms at low doses. (author)

  10. 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.)

  11. Radiation absorbed dose estimates for [1-carbon-11]-glucose in adults: The effects of hyperinsulinemia

    International Nuclear Information System (INIS)

    Powers, W.J.

    1996-01-01

    As preparation for studies of blood-brain glucose transport in diabetes mellitus, radiation absorbed dose estimates from intravenous administration of [1- 11 C]-glucose for 24 internal organs, lens, blood and total body were calculated for three physiologic conditions: euinsulinemic euglycemia, hyperinsulinemic euglycemia and hyperinsulinemic hyperglycemia. Cumulated activities in blood, insulin-independent and insulin-dependent compartments were calculated from blood time-activity curves in normal human volunteers and macaques. Apportionment of cumulated activity to individual organs in insulin-dependent and insulin-independent compartments was based on previously published data. Absorbed doses were calculated with the computer program MIRDOSE 3 for the 70-kg adult phantom. S for blood was calculated separately. The heart wall, lungs and spleen were the organs receiving the highest dose. The effect of hyperinsulinemia was demonstrated by the increase in adsorbed dose to the muscle, heart and blood with a decrease to other internal organs. This effect was more pronounced during hyperinsulinemic hyperglycemia. Hyperinsulinemia produced a decrease in effective dose due to the decrease in cumulated activity in organs with specified weighting factors greater than 0.05. The effective dose per study for [1- 11 C]-glucose is comparable to that reported for 2-deoxy-[2- 18 F]-glucose. 43 refs., 1 fig., 4 tabs

  12. Clinical dosimetry with plastic scintillators - Almost energy independent, direct absorbed dose reading with high resolution

    Energy Technology Data Exchange (ETDEWEB)

    Quast, U; Fluehs, D [Department of Radiotherapy, Essen (Germany). Div. of Clinical Radiation Physics; Fluehs, D; Kolanoski, H [Dortmund Univ. (Germany). Inst. fuer Physik

    1996-08-01

    Clinical dosimetry is still far behind the goal to measure any spatial or temporal distribution of absorbed dose fast and precise without disturbing the physical situation by the dosimetry procedure. NE 102A plastic scintillators overcome this border. These tissue substituting dosemeter probes open a wide range of new clinical applications of dosimetry. This versatile new dosimetry system enables fast measurement of the absorbed dose to water in water also in regions with a steep dose gradient, close to interfaces, or in partly shielded regions. It allows direct reading dosimetry in the energy range of all clinically used external photon and electron beams, or around all branchytherapy sources. Thin detector arrays permit fast and high resolution measurements in quality assurance, such as in-vivo dosimetry or even afterloading dose monitoring. A main field of application is the dosimetric treatment planning, the individual optimization of brachytherapy applicators. Thus, plastic scintillator dosemeters cover optimally all difficult fields of clinical dosimetry. An overview about its characteristics and applications is given here. 20 refs, 1 fig.

  13. ESR dating of elephant teeth and radiation dose rate estimation in soil

    International Nuclear Information System (INIS)

    Taisoo Chong; Ohta, Hiroyuki; Nakashima, Yoshiyuki; Iida, Takao; Saisho, Hideo

    1989-01-01

    Chemical analysis of 238 U, 232 Th and 40 K in the dentine as well as enamel of elephant tooth fossil has been carried out in order to estimate the internal absorbed dose rate of the specimens, which was estimated to be (39±4) mrad/y on the assumption of early uptake model of radionuclides. The external radiation dose rate in the soil including the contribution from cosmic rays was also estimated to be (175±18) mrad/y with the help of γ-ray spectroscopic techniques of the soil samples in which the specimens were buried. The 60 Co γ-ray equivalent accumulated dose of (2±0.2) x 10 4 rad for the tooth enamel gave ''ESR age'' of (9±2) x 10 4 y, which falls in the geologically estimated range between 3 x 10 4 and 30 x 10 4 y before the present. (author)

  14. Determination of Radiation Absorbed Dose to Primary Liver Tumors and Normal Liver Tissue Using Post Radioembolization 90Y PET

    Directory of Open Access Journals (Sweden)

    Shyam Mohan Srinivas

    2014-10-01

    Full Text Available Background: Radioembolization with Yttrium-90 (90Y microspheres is becoming a more widely used transcatheter treatment for unresectable hepatocellular carcinoma (HCC. Using post-treatment 90Y PET/CT scans,the distribution of microspheres within the liver can be determined and quantitatively assessesed . We studied the radiation dose of 90Y delivered to liver and treated tumors.Methods: This retrospective study of 56 patients with HCC, including analysis of 98 liver tumors, measured and correlated the dose of radiation delivered to liver tumors and normal liver tissue using glass microspheres (TheraSpheres® to the frequency of complications with mRECIST. 90Y PET/CT and triphasic liver CT scans were used to contour treated tumor and normal liver regions and determine their respective activity concentrations. An absorbed dose factor was used to convert the measured activity concentration (Bq/mL to an absorbed dose (Gy.Results: The 98 studied tumors received a mean dose of 169 Gy (mode 90-120 Gy;range 0-570 Gy. Tumor response by mRECIST criteria was performed for 48 tumors that had follow up scans. There were 21 responders (mean dose 215 Gy and 27 nonresponders (mean dose 167 Gy. The association between mean tumor absorbed dose and response suggests a trend but did not reach statistical significance (p=0.099. Normal liver tissue received a mean dose of 67 Gy (mode 60-70 Gy; range 10-120 Gy. There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p=0.036.Conclusion: Our cohort of patients showed a possible dose response trend for the tumors. Collateral dose to normal liver is nontrivial and can have clinical implications. These methods help us understand whether patient adverse events, treatment success, or treatment failure can be attributed to the dose which the tumor or normal liver received.

  15. The design of a calorimetric standard of ionising radiation absorbed dose

    International Nuclear Information System (INIS)

    Huntley, R.B.

    1981-05-01

    The design of a calorimetric working standard of ionising radiation absorbed dose is discussed. A brief history of the appropriate quantities and units of measurement is given. Detailed design considerations follow a summary of the relevant literature. The methods to be used to relate results to national standards of measurement are indicated, including the need for various correction factors. A status report is given on the construction and testing program

  16. 90Y/90 Sr electron induced damages in an essential eucalyptus oil related to the absorbed dose

    International Nuclear Information System (INIS)

    Heredia Cardona, J.A.; Diaz Rizo, O.; Martinez Luzardo, F.; Quert, R.

    2007-01-01

    A good irradiation geometry was achieved in order to carry out the irradiation of an essential eucalyptus oil with a 90 Y/ 90 Sr electron source. The Monte Carlo simulation code MCNP-4C was employed to determine the absorbed doses in this particular experimental configuration. It also helped us to understand which electrons (from an energetic point of view) were responsible for the damages. In order to identify the induced damages, the irradiated samples were studied by mass spectrometry. The obtained results were related to the absorbed doses determined by the computational simulation

  17. Three-dimensional absorbed dose determinations by N.M.R. analysis of phantom-dosemeters

    International Nuclear Information System (INIS)

    Gambarini, G.; Birattari, C.; Fumagalli, M.L.; Vai, A.; Monti, D.; Salvadori, P.; Facchielli, L.; Sichirollo, A.E.

    1996-01-01

    Magnetic resonance imaging of a tissue-equivalent phantom is a promising technique for three-dimensional determination of absorbed dose from ionizing radiation. A reliable method of determining the spatial distribution of absorbed dose is indispensable for the planning of treatment in the presently developed radiotherapy techniques aimed at obtaining high energy selectively delivered to cancerous tissues, with low dose delivered to the surrounding healthy tissue. Aqueous gels infused with the Fricke dosemeter (i.e. with a ferrous sulphate solution), as proposed in 1984 by Gore et al., have shown interesting characteristics and, in spite of some drawbacks that cause a few limitations to their utilisation, they have shown the feasibility of three-dimensional dose determinations by nuclear magnetic resonance (NMR) imaging. Fricke-infused agarose gels with various compositions have been analysed, considering the requirements of the new radiotherapy techniques, in particular Boron Neutron Capture Therapy (B.N.C.T.) and proton therapy. Special attention was paid to obtain good tissue equivalence for every radiation type of interest. In particular, the tissue equivalence for thermal neutrons, which is a not simple problem, has also been satisfactorily attained. The responses of gel-dosemeters having the various chosen compositions have been analysed, by mean of NMR instrumentation. Spectrophotometric measurements have also been performed, to verify the consistence of the results. (author)

  18. Calculation of absorbed dose at 0.07, 3.0 and 10.0 mm depths in a slab phantom for monoenergetic electrons

    International Nuclear Information System (INIS)

    Hirayama, H.

    1994-01-01

    The general-purpose electron gamma shower Monte Carlo code EGS4 has been used to calculate absorbed doses at 0.07, 3.0 and 10.0 mm depths per unit fluence for broad parallel beams of monoenergetic electrons impinging at an incident angle α on a slab phantom (30 cm x 30 cm x 15 cm) of polymethyl methacrylate (PMMA), water and ICRU 4-element tissue required by EURADOS WG4 for a revision of ICRP Publication 51. Absorbed doses at 7, 300 and 1000 mg.cm -2 were also calculated for PMMA. The electron kinetic energy range covered is 50 keV to 10 MeV. The incident angle (α) varies from 0 o to 75 o with an increment of 15 o . The calculated results are presented as tables. The depth against absorbed dose curves and dependence of the absorbed dose at each depth on the incident electron energy, incident angle and phantom material are also presented and discussed. (author)

  19. Monte Carlo dosimetry of the IRAsource high dose rate 192Ir brachytherapy source

    International Nuclear Information System (INIS)

    Sarabiasl, Akbar; Ayoobian, Navid; Jabbari, Iraj; Poorbaygi, Hossein; Javanshir, Mohammad Reza

    2016-01-01

    High-dose-rate (HDR) brachytherapy is a common method for cancer treatment in clinical brachytherapy. Because of the different source designs, there is a need for specific dosimetry data set for each HDR model. The purpose of this study is to obtain detailed dose rate distributions in water phantom for a first prototype HDR 192 Ir brachytherapy source model, IRAsource, and compare with the other published works. In this study, Monte Carlo N-particle (MCNP version 4C) code was used to simulate the dose rate distributions around the HDR source. A full set of dosimetry parameters reported by the American Association of Physicists in Medicine Task Group No. 43U1 was evaluated. Also, the absorbed dose rate distributions in water, were obtained in an along-away look-up table. The dose rate constant, Λ, of the IRAsource was evaluated to be equal to 1.112 ± 0.005 cGy h −1 U −1 . The results of dosimetry parameters are presented in tabulated and graphical formats and compared with those reported from other commercially available HDR 192 Ir sources, which are in good agreement. This justifies the use of specific data sets for this new source. The results obtained in this study can be used as input data in the conventional treatment planning systems.

  20. Absorbed dose calculation of the energy deposition close to bone, lung and soft tissue interfaces in molecular radiotherapy

    International Nuclear Information System (INIS)

    Fernandez, M.; Lassman, M.

    2015-01-01

    Full text of publication follows. Aim: for voxel-based dosimetry in molecular radiotherapy (MRT) based on tabulated voxel S-values these values are usually obtained only for soft tissue. In order to study the changes in the dose deposition patterns at interfaces between different materials we have performed Monte Carlo simulations. Methods: the deposited energy patterns were obtained using the Monte-Carlo radiation code MCNPX v2.7 for Lu 177 (medium-energy) and Y 90 (high-energy). The following interfaces were studied: soft tissue-bone and soft tissue-lungs. For this purpose a volume of soft tissue homogeneously filled with Lu 177 or Y 90 was simulated at the interface to 3 different volumes containing no activity: soft tissue, lungs and bone. The emission was considered to be isotropic. The dimensions were chosen to ensure that the energy deposited by all generated particles was scored. The materials were defined as recommended by ICPR46; the decay schemes of Eckerman and Endo were used. With these data the absorbed dose patterns normalized to the maximum absorbed dose in the source region (soft tissue) were calculated. Results: the absorbed dose fractions in the boundary with soft tissue, bone and lungs are 50%, 47% and 57%, respectively, for Lu 177 and 50%, 47% and 51% for Y 90 . The distances to the interface at which the absorbed fractions are at 0.1% are 1.0, 0.6 and 3.0 mm for Lu 177 and 7.0, 4.0 and 24 mm for Y 90 , for soft tissue, bone and lungs respectively. Conclusions: in MRT, the changes in the absorbed doses at interfaces between soft tissue and bone/lungs need to be considered for isotopes emitting high energy particles. (authors)

  1. Absorbed dose estimates to structures of the brain and head using a high-resolution voxel-based head phantom

    International Nuclear Information System (INIS)

    Evans, Jeffrey F.; Blue, Thomas E.; Gupta, Nilendu

    2001-01-01

    The purpose of this article is to demonstrate the viability of using a high-resolution 3-D head phantom in Monte Carlo N-Particle (MCNP) for boron neutron capture therapy (BNCT) structure dosimetry. This work describes a high-resolution voxel-based model of a human head and its use for calculating absorbed doses to the structures of the brain. The Zubal head phantom is a 3-D model of a human head that can be displayed and manipulated on a computer. Several changes were made to the original head phantom which now contains over 29 critical structures of the brain and head. The modified phantom is a 85x109x120 lattice of voxels, where each voxel is 2.2x2.2x1.4 mm 3 . This model was translated into MCNP lattice format. As a proof of principle study, two MCNP absorbed dose calculations were made (left and right lateral irradiations) using a uniformly distributed neutron disk source with an 1/E energy spectrum. Additionally, the results of these two calculations were combined to estimate the absorbed doses from a bilateral irradiation. Radiobiologically equivalent (RBE) doses were calculated for all structures and were normalized to 12.8 Gy-Eq. For a left lateral irradiation, the left motor cortex receives the limiting RBE dose. For a bilateral irradiation, the insula cortices receive the limiting dose. Among the nonencephalic structures, the parotid glands receive RBE doses that were within 15% of the limiting dose

  2. Changes in the Number of Double-Strand DNA Breaks in Chinese Hamster V79 Cells Exposed to γ-Radiation with Different Dose Rates

    Directory of Open Access Journals (Sweden)

    Andreyan N. Osipov

    2013-07-01

    Full Text Available A comparative investigation of the induction of double-strand DNA breaks (DSBs in the Chinese hamster V79 cells by γ-radiation at dose rates of 1, 10 and 400 mGy/min (doses ranged from 0.36 to 4.32 Gy was performed. The acute radiation exposure at a dose rate of 400 mGy/min resulted in the linear dose-dependent increase of the γ-H2AX foci formation. The dose-response curve for the acute exposure was well described by a linear function y = 1.22 + 19.7x, where “y” is an average number of γ-H2AX foci per a cell and “x” is the absorbed dose (Gy. The dose rate reduction down to 10 mGy/min lead to a decreased number of γ-H2AX foci, as well as to a change of the dose-response relationship. Thus, the foci number up to 1.44 Gy increased and reached the “plateau” area between 1.44 and 4.32 Gy. There was only a slight increase of the γ-H2AX foci number (up to 7 in cells after the protracted exposure (up to 72 h to ionizing radiation at a dose rate of 1 mGy/min. Similar effects of the varying dose rates were obtained when DNA damage was assessed using the comet assay. In general, our results show that the reduction of the radiation dose rate resulted in a significant decrease of DSBs per cell per an absorbed dose.

  3. Comparison of absorbed dose of two protocols of tomographic scanning in PET/CT exams

    International Nuclear Information System (INIS)

    Paiva, F.G.

    2017-01-01

    Positron Emission Tomography (PET) associated with Computed Tomography (CT) allows the fusion of functional and anatomical images. When compared to other diagnostic techniques, PET-CT subjects patients to higher levels of radiation, because two modalities are used in a single exam. In this study, the doses absorbed in 19 patient organs from the tomographic scan were evaluated. Radiochromic films were correctly positioned in the Alderson anthropomorphic simulator, male version. For evaluation, two whole body scan protocols were compared. For evaluation, two whole body scan protocols were compared. An increase of up to 600% in the absorbed dose in the pituitary was observed when the protocols were compared, with the lowest observed increase of approximately 160% for the liver. It is concluded that the dose from CT in patients submitted to PET-CT scanning is higher in the protocol used for diagnosis. Considering the high cost of PET-CT exam, in many cases it is preferable that the CT examination is of diagnostic quality, and not only for anatomical mapping, an argument based on the Principle of Justification

  4. Functional results of radioiodine therapy with a 300-GY absorbed dose in Graves' disease

    International Nuclear Information System (INIS)

    Willemsen, U.F.; Knesewitsch, P.; Kreisig, T.; Pickardt, C.R.; Kirsch, C.M.

    1993-01-01

    The aim of this study was to assess the results of high-dose radioiodine therapy given to 43 patients with recurrent hyperthyroidism due to Graves' disease between 1986 and 1992. We chose an intrathyroidal absorbed dose of 300 Gy and determined the applied activity individually, which ranged from 240 to 3120 MBq with a median of 752 MBq. Hperthyroidism was eliminated in 86% of cases after 3 months and in 100% after 12 months. No patient required a second radioiodine treatment. The incidnece of hyperthyroidism was 63% after 3 months and 93% after 18 months. Neither the pretherapeutic thyroid-stimulating immunoglobulin level nor the degree of co-existing endocrine ophthalmopathy was correlated with the time at which hypothyroidism developed. Patients with previous radioiodine therapy developed hypothyroidism earlier than patients with previous thyroid surgery. The results show that ablative radioiodine therapy with a 300-Gy absorbed dose is a very effective treatment of hyperthyroidism in Graves' disease, but it should be restricted to patients with recurrent hyperthyroidism combined with severe co-existing disorders or episodes of unfavourable reactions to antithyroid drugs. (orig.)

  5. Absorbed dose to man from the Se-75 labeled conjugated bile salt SeHCAT: concise communication

    International Nuclear Information System (INIS)

    Soundy, R.G.; Simpson, J.D.; Ross, H.M.; Merrick, M.V.

    1982-01-01

    The absorbed radiation dose that would result from the oral or intravenous administration of SeHCAT (23-[ 75 Se]selena-25-homotaurocholate) has been calculated using the MIRD tables and formulas and data from measurements of whole-body distribution and from long-term whole-body counting in rats, mice, and man. When SeHCAT is administered to normal subjects, the gallbladder is the critical organ, receiving 12 mrad (oral dose) or 22 mrad (i.v.) per microcurie. The whole-body dose is 1 mrad/μCi, whatever the route of administration. In severe hepatic failure the liver might receive 200 mrad/μCi. The activity likely to be used in routine clinical practice is 10 μCi. Where a whole-body counter is used, an activity of 1 μCi has proved adequate. Even at an administered activity of 25 μCi, the absorbed dose is small compared with established techniques of investigating the gastrointestinal tract

  6. Absorbed dose to man from the Se-75 labeled conjugated bile salt SeHCAT: concise communication

    International Nuclear Information System (INIS)

    Soundy, R.G.; Simpson, J.D.; Ross, H.M.; Merrick, M.V.

    1982-01-01

    The absorbed radiation dose that would result from the oral or intravenous administration of SeHCAT (23-[75Se]selena-25-homotaurocholate) has been calculated using the MIRD tables and formulas and data from measurements of whole-body distribution and from long-term whole-body counting in rats, mice, and man. When SeHCAT is administered to normal subjects, the gallbladder is the critical organ, receiving 12 mrad (oral dose) or 22 mrad (i.v.) per microcurie. The whole-body dose is 1 mrad/microCi, whatever the route of administration. In severe hepatic failure the liver might receive 200 mrad/microCi. The activity likely to be used in routine clinical practice is 10 microCi. Where a whole-body counter is used, an activity of 1 microCi has proved adequate. Even at an administered activity of 25 microCi, the absorbed dose is small compared with established techniques of investigating the gastrointestinal tract

  7. Preclinical Study of 68Ga-DOTATOC: Biodistribution Assessment in Syrian Rats and Evaluation of Absorbed Dose in Human Organs.

    Science.gov (United States)

    Naderi, Mojdeh; Zolghadri, Samaneh; Yousefnia, Hassan; Ramazani, Ali; Jalilian, Amir Reza

    2016-01-01

    Gallium-68 DOTA-DPhe 1 -Tyr 3 -Octreotide ( 68 Ga-DOTATOC) has been applied by several European centers for the treatment of a variety of human malignancies. Nevertheless, definitive dosimetric data are yet unavailable. According to the Society of Nuclear Medicine and Molecular Imaging, researchers are investigating the safety and efficacy of this radiotracer to meet Food and Drug Administration requirements. The aim of this study was to introduce the optimized procedure for 68 Ga-DOTATOC preparation, using a novel germanium-68 ( 68 Ge)/ 68 Ga generator in Iran and evaluate the absorbed doses in numerous organs with high accuracy. The optimized conditions for preparing the radiolabeled complex were determined via several experiments by changing the ligand concentration, pH, temperature and incubation time. Radiochemical purity of the complex was assessed, using high-performance liquid chromatography and instant thin-layer chromatography. The absorbed dose of human organs was evaluated, based on biodistribution studies on Syrian rats via Radiation Absorbed Dose Assessment Resource Method. 68 Ga-DOTATOC was prepared with radiochemical purity of >98% and specific activity of 39.6 MBq/nmol. The complex demonstrated great stability at room temperature and in human serum at 37°C at least two hours after preparation. Significant uptake was observed in somatostatin receptor-positive tissues such as pancreatic and adrenal tissues (12.83 %ID/g and 0.91 %ID/g, respectively). Dose estimations in human organs showed that the pancreas, kidneys and adrenal glands received the maximum absorbed doses (0.105, 0.074 and 0.010 mGy/MBq, respectively). Also, the effective absorbed dose was estimated at 0.026 mSv/MBq for 68 Ga-DOTATOC. The obtained results showed that 68 Ga-DOTATOC can be considered as an effective agent for clinical PET imaging in Iran.

  8. Calculation of absorbed doses in sphere volumes around the Mammosite using the Monte Carlo simulation code MCNPX; Calculo de dosis absorbida en volumenes esfericos alrededor del Mammosite utilizando el codigo de simulacion Monte Carlo MCNPX

    Energy Technology Data Exchange (ETDEWEB)

    Rojas C, E. L. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2008-07-01

    The objective of this study is to investigate the changes observed in the absorbed doses in mammary gland tissue when irradiated with a equipment of high dose rate known as Mammosite and introducing material resources contrary to the tissue that constitutes the mammary gland. The modeling study is performed with the code MCNPX, 2005 version, the equipment and the mammary gland and calculating the absorbed doses in tissue when introduced small volumes of air or calcium in the system. (Author)

  9. Investigation of the dose rate dependency of the PAGAT gel dosimeter at low dose rates

    International Nuclear Information System (INIS)

    Zehtabian, M.; Faghihi, R.; Zahmatkesh, M.H.; Meigooni, A.S.; Mosleh-Shirazi, M.A.; Mehdizadeh, S.; Sina, S.; Bagheri, S.

    2012-01-01

    Medical physicists need dosimeters such as gel dosimeters capable of determining three-dimensional dose distributions with high spatial resolution. To date, in combination with magnetic resonance imaging (MRI), polyacrylamide gel (PAG) polymers are the most promising gel dosimetry systems. The purpose of this work was to investigate the dose rate dependency of the PAGAT gel dosimeter at low dose rates. The gel dosimeter was used for measurement of the dose distribution around a Cs-137 source from a brachytherapy LDR source to have a range of dose rates from 0.97 Gy h −1 to 0.06 Gy h −1 . After irradiation of the PAGAT gel, it was observed that the dose measured by gel dosimetry was almost the same at different distances (different dose rates) from the source, although the points nearer the source had been expected to receive greater doses. Therefore, it was suspected that the PAGAT gel is dose rate dependent at low dose rates. To test this further, three other sets of measurements were performed by placing vials containing gel at different distances from a Cs-137 source. In the first two measurements, several plastic vials were exposed to equal doses at different dose rates. An ionization chamber was used to measure the dose rate at each distance. In addition, three TLD chips were simultaneously irradiated in order to verify the dose to each vial. In the third measurement, to test the oxygen diffusion through plastic vials, the experiment was repeated again using plastic vials in a nitrogen box and glass vials. The study indicates that oxygen diffusion through plastic vials for dose rates lower than 2 Gy h −1 would affect the gel dosimeter response and it is suggested that the plastic vials or (phantoms) in an oxygen free environment or glass vials should be used for the dosimetry of low dose rate sources using PAGAT gel to avoid oxygen diffusion through the vials.

  10. Absorbed dose/melting heat dependence studies for the PVDF homopolymer

    International Nuclear Information System (INIS)

    Batista, Adriana S.M.; Gual, Maritza R.; Pereira, Claubia

    2013-01-01

    Differential Scanning Calorimetry (DSC) of gamma irradiated Poly (vinylidene Fluoride) [PVDF] homopolymer has been studied in connection with the use of material in industrial high gamma dose measurement. Interaction between gamma radiation and PVDF leads to the radio-induction of C=O and conjugated C=C bonds, as it can be inferred from previous infrared (FTIR) and ultraviolet-visible (UV-Vis) spectrometric data. These induced defects result in a decrease of the polymer crystallinity that can be followed with DSC scans, by measuring the latent heat during the melting transition (Hmelt). After a systematic investigation, we have found that Hmelt is unambiguously related to the delivered doses ranging from 100 to 2,000 kGy of gamma radiation. One the other hand, further fading investigation analysis has proved that the Hmelt x Dose relationship can be fitted by an exponential function that remains constant for several months. Both the very large range of dose measurement and also the possibility of evaluating high gamma doses until five months after irradiation make PVDF homopolymers very good candidates to be investigated as commercial high gamma dose dosimeters. The high gamma dose irradiation facilities in Brazil used to develop high dose dosimeters are all devoted to industrial and medical purposes. Therefore, in view of the uncertainties involved in the dose measurements related to the electronic equilibrium correction factors and backscattering in the isodose curves used at the irradiation setup, a validation process is required to correctly evaluate the delivered absorbed doses. The sample irradiations were performed with a Co-60 source, at 12kGy/h and 2,592 kGy/h, in the high gamma dose facilities at Centro de Desenvolvimento da Tecnologia Nuclear CDTN/CNEN, Belo Horizonte, Brazil. The comparison of the curve of the Hmelt vs Dose is presented in this paper. (author)

  11. Absorbed dose estimation of gonads resulting from fault work of staff during injection of radiopharmaceuticals to the patients

    International Nuclear Information System (INIS)

    Maleki, M.; Karimian, A.

    2012-01-01

    Radiopharmaceuticals are used in nuclear medicine in a variety of diagnostic and therapeutic procedures and generally delivered to the patient via intravenous injection. 201 Tl and 99m Tc are the two most used radiopharmaceuticals in nuclear medicine. The maximum activity injected to the patient in nuclear medicine for 201 Tl and 99m Tc is 5 and 20-25 mCi respectively. In this research by using Monte Carlo method and MCNPX code the absorbed dose to Gonads due to drop of radiopharmaceutical on foot thigh during injection to the patient has been calculated. The activity of 201 Tl and 99m Tc has been considered 1 and 5mCi respectively. The amount of absorbed dose in gonads for 99m Tc for male and female during 8 hours of work has been measured 0.37 and 0.055 μSv respectively. Also the amount of absorbed dose for 201 Tl during working hours at first day, second day and third day after work fault for male has been measured 0.387, 0.308 and 0.246 μSv and for female 0.06, 0.048 and 0.038 μSv respectively. The total dose in these three working days for male and female has been 0.941 and 0.146 μSv respectively. Since absorbed dose of gonads was far enough from the limits of ICRP, so it can be concluded that if a fault work occurs and even staff does not be aware there is no need to treat him. (authors)

  12. Supplemental computational phantoms to estimate out-of-field absorbed dose in photon radiotherapy

    Science.gov (United States)

    Gallagher, Kyle J.; Tannous, Jaad; Nabha, Racile; Feghali, Joelle Ann; Ayoub, Zeina; Jalbout, Wassim; Youssef, Bassem; Taddei, Phillip J.

    2018-01-01

    The purpose of this study was to develop a straightforward method of supplementing patient anatomy and estimating out-of-field absorbed dose for a cohort of pediatric radiotherapy patients with limited recorded anatomy. A cohort of nine children, aged 2-14 years, who received 3D conformal radiotherapy for low-grade localized brain tumors (LBTs), were randomly selected for this study. The extent of these patients’ computed tomography simulation image sets were cranial only. To approximate their missing anatomy, we supplemented the LBT patients’ image sets with computed tomography images of patients in a previous study with larger extents of matched sex, height, and mass and for whom contours of organs at risk for radiogenic cancer had already been delineated. Rigid fusion was performed between the LBT patients’ data and that of the supplemental computational phantoms using commercial software and in-house codes. In-field dose was calculated with a clinically commissioned treatment planning system, and out-of-field dose was estimated with a previously developed analytical model that was re-fit with parameters based on new measurements for intracranial radiotherapy. Mean doses greater than 1 Gy were found in the red bone marrow, remainder, thyroid, and skin of the patients in this study. Mean organ doses between 150 mGy and 1 Gy were observed in the breast tissue of the girls and lungs of all patients. Distant organs, i.e. prostate, bladder, uterus, and colon, received mean organ doses less than 150 mGy. The mean organ doses of the younger, smaller LBT patients (0-4 years old) were a factor of 2.4 greater than those of the older, larger patients (8-12 years old). Our findings demonstrated the feasibility of a straightforward method of applying supplemental computational phantoms and dose-calculation models to estimate absorbed dose for a set of children of various ages who received radiotherapy and for whom anatomies were largely missing in their original

  13. Absorbed dose determination in water in medium energy x-ray beam

    International Nuclear Information System (INIS)

    Nisevic, G.; Spasic-Jokic, V.

    1998-01-01

    Absorbed dose determination in water phantom in medium energy X-ray beam, according to IAEA recommendations is given. This method is applied on Radiotherapy department of Military Academy Hospital in Belgrade. Reference points of measurements are on depth of 5 cm and 2 cm as it recommended in ref. Experimental results are shown in aim to introduce new dosimetric concept based on air kerma calibration factor recommended for application in our radiotherapy centers (author)

  14. RaD-X: Complementary measurements of dose rates at aviation altitudes

    Science.gov (United States)

    Meier, Matthias M.; Matthiä, Daniel; Forkert, Tomas; Wirtz, Michael; Scheibinger, Markus; Hübel, Robert; Mertens, Christopher J.

    2016-09-01

    The RaD-X stratospheric balloon flight organized by the National Aeronautics and Space Administration was launched from Fort Sumner on 25 September 2015 and carried several instruments to measure the radiation field in the upper atmosphere at the average vertical cutoff rigidity Rc of 4.1 GV. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt) in cooperation with Lufthansa German Airlines supported this campaign with an independent measuring flight at the altitudes of civil aviation on a round trip from Germany to Japan. The goal was to measure dose rates under similar space weather conditions over an area on the Northern Hemisphere opposite to the RaD-X flight. Dose rates were measured in the target areas, i.e., around vertical cutoff rigidity Rc of 4.1 GV, at two flight altitudes for about 1 h at each position with acceptable counting statistics. The analysis of the space weather situation during the flights shows that measuring data were acquired under stable and moderate space weather conditions with a virtually undisturbed magnetosphere. The measured rates of absorbed dose in silicon and ambient dose equivalent complement the data recorded during the balloon flight. The combined measurements provide a set of experimental data suitable for validating and improving numerical models for the calculation of radiation exposure at aviation altitudes.

  15. Validation of a MOSFET dosemeter system for determining the absorbed and effective radiation doses in diagnostic radiology.

    Science.gov (United States)

    Manninen, A-L; Kotiaho, A; Nikkinen, J; Nieminen, M T

    2015-04-01

    This study aimed to validate a MOSFET dosemeter system for determining absorbed and effective doses (EDs) in the dose and energy range used in diagnostic radiology. Energy dependence, dose linearity and repeatability of the dosemeter were examined. The absorbed doses (ADs) were compared at anterior-posterior projection and the EDs were determined at posterior-anterior, anterior-posterior and lateral projections of thoracic imaging using an anthropomorphic phantom. The radiation exposures were made using digital radiography systems. This study revealed that the MOSFET system with high sensitivity bias supply set-up is sufficiently accurate for AD and ED determination. The dosemeter is recommended to be calibrated for energies 80 kVp. The entrance skin dose level should be at least 5 mGy to minimise the deviation of the individual dosemeter dose. For ED determination, dosemeters should be implanted perpendicular to the surface of the phantom to prevent the angular dependence error. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Effects of trapped proton flux anisotropy on dose rates in low Earth orbit

    International Nuclear Information System (INIS)

    Badhwar, G.D.; Kushin, V.V.; Akatov, Yu A.; Myltseva, V.A.

    1999-01-01

    Trapped protons in the South Atlantic Anomaly (SAA) have a rather narrow pitch angle distribution and exhibit east-west anisotropy. In low Earth orbits, the E-W effect results in different amounts of radiation dose received by different sections of the spacecraft. This effect is best studied on missions in which the spacecraft flies in a fixed orientation. The magnitude of the effect depends on the particle energy and altitude through the SAA. In this paper, we describe a clear example of this effect from measurements of radiation dose rates and linear energy transfer spectra made on Space Shuttle flight STS-94 (28.5 deg. inclination x 296 km altitude). The ratio of dose rates from the two directions at this location in the mid-deck was 2.7. As expected from model calculations, the spectra from the two directions are different, that is the ratio is energy dependent. The data can be used to distinguish the anisotropy models. The flight carried an active tissue equivalent proportional counter (TEPC), and passive thermoluminscent detectors (TLDs), and two types of nuclear emulsions. Using nuclear emulsions, charged particles and secondary neutron energy spectra were measured. The combined galactic cosmic radiation+trapped charged particle lineal energy spectra measured by the TEPC and the linear energy transfer spectrum measured by nuclear emulsions are in good agreement. The charged particle absorbed dose rates varied from 112 to 175 μGy/day, and dose equivalent rates from 264.3 to 413 μSv/day. Neutrons in the 1-10 MeV contributed a dose rate of 3.7 μGy/day and dose equivalent rate of 30.8 μSv/day, respectively

  17. Effects of trapped proton flux anisotropy on dose rates in low Earth orbit.

    Science.gov (United States)

    Badhwar, G D; Kushin, V V; Akatov YuA; Myltseva, V A

    1999-06-01

    Trapped protons in the South Atlantic Anomaly (SAA) have a rather narrow pitch angle distribution and exhibit east-west anisotropy. In low Earth orbits, the E-W effect results in different amounts of radiation dose received by different sections of the spacecraft. This effect is best studied on missions in which the spacecraft flies in a fixed orientation. The magnitude of the effect depends on the particle energy and altitude through the SAA. In this paper, we describe a clear example of this effect from measurements of radiation dose rates and linear energy transfer spectra made on Space Shuttle flight STS-94 (28.5 degree inclination x 296 km altitude). The ratio of dose rates from the two directions at this location in the mid-deck was 2.7. As expected from model calculations, the spectra from the two directions are different, that is the ratio is energy dependent. The data can be used to distinguish the anisotropy models. The flight carried an active tissue equivalent proportional counter (TEPC), and passive thermoluminscent detectors (TLDs), and two types of nuclear emulsions. Using nuclear emulsions, charged particles and secondary neutron energy spectra were measured. The combined galactic cosmic radiation+trapped charged particle lineal energy spectra measured by the TEPC and the linear energy transfer spectrum measured by nuclear emulsions are in good agreement. The charged particle absorbed dose rates varied from 112 to 175 microGy/day, and dose equivalent rates from 264.3 to 413 microSv/day. Neutrons in the 1-10 MeV contributed a dose rate of 3.7 microGy/day and dose equivalent rate of 30.8 microSv/day, respectively.

  18. Comparison between Radiology Science Laboratory, Brazil (LCR) and National Research Council, Canada (NRC) of the absorbed dose in water using Fricke dosimetry

    International Nuclear Information System (INIS)

    Salata, Camila; David, Mariano Gazineu; Almeida, Carlos Eduardo de

    2014-01-01

    The absorbed dose to water standards for HDR brachytherapy dosimetry developed by the Radiology Science Laboratory, Brazil (LCR) and the National Research Council, Canada (NRC), were compared. The two institutions have developed absorbed dose standards based on the Fricke dosimetry system. There are significant differences between the two standards as far as the preparation and readout of the Fricke solution and irradiation geometry of the holder. Measurements were done at the NRC laboratory using a single Ir-192 source. The comparison of absorbed dose measurements was expressed as the ratio Dw(NRC)/Dw(LCR), which was found to be 1.026. (author)

  19. An estimate by two methods of thyroid absorbed doses due to BRAVO fallout in several Northern Marshall Islands.

    Science.gov (United States)

    Musolino, S V; Greenhouse, N A; Hull, A P

    1997-10-01

    Estimates of the thyroid absorbed doses due to fallout originating from the 1 March 1954 BRAVO thermonuclear test on Bikini Atoll have been made for several inhabited locations in the Northern Marshall Islands. Rongelap, Utirik, Rongerik and Ailinginae Atolls were also inhabited on 1 March 1954, where retrospective thyroid absorbed doses have previously been reconstructed. The current estimates are based primarily on external exposure data, which were recorded shortly after each nuclear test in the Castle Series, and secondarily on soil concentrations of 137Cs in samples collected in 1978 and 1988, along with aerial monitoring done in 1978. The external exposures and 137Cs soil concentrations were representative of the atmospheric transport and deposition patterns of the entire Castle Series tests and show that the BRAVO test was the major contributor to fallout exposure during the Castle series and other test series which were carried out in the Marshall Islands. These data have been used as surrogates for fission product radioiodines and telluriums in order to estimate the range of thyroid absorbed doses that may have occurred throughout the Marshall Islands. Dosimetry based on these two sets of estimates agreed within a factor of 4 at the locations where BRAVO was the dominant contributor to the total exposure and deposition. Both methods indicate that thyroid absorbed doses in the range of 1 Gy (100 rad) may have been incurred in some of the northern locations, whereas the doses at southern locations did not significantly exceed levels comparable to those from worldwide fallout. The results of these estimates indicate that a systematic medical survey for thyroid disease should be conducted, and that a more definitive dose reconstruction should be made for all the populated atolls and islands in the Northern Marshall Islands beyond Rongelap, Utirik, Rongerik and Ailinginae, which were significantly contaminated by BRAVO fallout.

  20. An estimate by two methods of thyroid absorbed doses due to BRAVO fallout in several northern Marshall Islands

    International Nuclear Information System (INIS)

    Musolino, S.V.; Hull, A.P.; Greenhouse, N.A.

    1997-01-01

    Estimates of the thyroid absorbed doses due to fallout originating from the 1 March 1954 BRAVO thermonuclear test on Bikini Atoll have been made for several inhabited locations in the Northern Marshall Islands. Rongelap, Utirik, Rongerik and Ailinginae Atolls were also inhabited on 1 March 1954, where retrospective thyroid absorbed doses have previously been reconstructed. Current estimates are based primarily on external exposure data, which were recorded shortly after each nuclear test in the Castle Series, and secondarily on soil concentrations of 137 Cs in samples collected in 1978 and 1988, along with aerial monitoring done in 1978. External exposures and 137 Cs Soil concentrations were representative of the atmospheric transport and deposition patterns of the entire Castle Series tests and show that the BRAVO test was the major contributor to fallout exposure during the Castle series and other test series which were carried out in the Marshall Islands. These data have been used as surrogates for fission product radioiodines and telluriums in order to estimate the range of thyroid absorbed doses that may have occurred throughout the Marshall Islands. Dosimetry based on these two sets of estimates agreed within a factor of 4 at the locations where BRAVO was the dominant contributor to the total exposure and deposition. Both methods indicate that thyroid absorbed doses in the range of 1 Gy (100 rad) may have been incurred in some of the northern locations, whereas the doses at southern locations did not significantly exceed levels comparable to those from worldwide fallout. The results of these estimates indicate that a systematic medical survey for thyroid disease should be conducted, and that a more definitive dose reconstruction should be made for all the populated atolls and islands in the Northern Marshall Islands beyond Rongelap, Utirik, Rongerik and Ailinginae, which were significantly contaminated by BRAVO fallout. 30 refs., 2 figs., 10 tabs

  1. Absorbed dose in AgBr in direct film for photon energies (<150 keV): relation to optical density. Theoretical calculation and experimental evaluation

    International Nuclear Information System (INIS)

    Helmrot, E.; Alm Carlsson, G.

    1996-01-01

    Calculations of absorbed dose in the silver bromide were compared with measurements of optical densities in Ultra-speed and Ektaspeed films for a broad range (25-145 kV) of X-ray energy. The calculated absorbed dose values were appropriately averaged over the complete photon energy spectrum, which was determined experimentally using a Compton spectrometer. For the whole range of tube potentials used, the measured optical densities of the films were found to be proportional to the mean absorbed dose in the AgBr grains calculated according to GREENING's theory. They were also found to be proportional to the collision kerma in silver bromide (K c,AgBr ) indicating proportionality between K c,AgBr and the mean absorbed dose in silver bromide. While GREENING's theory shows that the quotient of the mean absorbed dose in silver bromide and K c,AgBr varies with photon energy, this is not apparent when averaged over the broad (diagnostic) X-ray energy spectra used here. Alternatively, proportionality between K c,AgBr and the mean absorbed dose in silver bromide can be interpreted as resulting from a combination of the SPIERS-CHARLTON theory, valid at low photon energies ( c,AgBr (at the position of the film) independent of photon energy. The importance of taking the complete X-ray energy spectrum into full account in deriving K c,AgBr is clearly demonstrated, showing that the concept of effective energy must be used with care. (orig./HP)

  2. Dose determination with nitro blue tetrazolium containing radiochromic dye films by measuring absorbed and reflected light

    DEFF Research Database (Denmark)

    Kovács, A.; Baranyai, M.; Wojnárovits, L.

    2000-01-01

    determination in a wide dose range both by absorbance and reflectance measurements. The concept of measuring reflected light from dose labels has been discussed earlier and emerged recently due to the requirement of introducing semiquantitative label dose indicators for quarantine control. The usefulness...... of the method was studied using the newly developed radiochromic dye films as well as already existing ones. (C) 2000 Elsevier Science Ltd. All rights reserved....

  3. Absorbed dose to the human adrenals from iodomethylnorcholesterol (I-131) NP-59: concise communication

    International Nuclear Information System (INIS)

    Carey, J.E.; Thrall, J.H.; Freitas, J.E.; Beierwaltes, W.H.

    1979-01-01

    During the past 2 yrs, adrenal uptake percentage values were measured in more than 40 patients, using an external counting technique. They suggest that the absorbed dose to the adrenals is significantly less than the 150 rads/mCi previously estimated using concentration values from animal adrenals. The measured combined uptake percentage for both adrenals ranged from 0.15% to 0.52% in 21 patients without evidence of adrenal disease, with a mean of 0.33% +- 0.1%; also from 0.22% to 1.5% in 22 patients with Cushing's disease, with a mean uptake of 0.78% +- 0.35%. The absorbed dose to the adrenals was estimated to be 25 rads/mCi for patients without evidence of adrenal disease, and 57 rads/mCi for patients with Cushing's disease. Both values are calculated for the respective mean uptake percentages by using the MIRD formalism

  4. Calculation of absorbed dose in water by chemical Fricke dosimetry; Calculo de dose absorvida na agua por dosimetria quimica Fricke

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Adenilson Paiva, E-mail: adenilson-fisica@hotmail.com.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil); Meireles, Ramiro Conceicao [Fundacao do Cancer, Rio de Janeiro, RJ (Brazil)

    2016-07-01

    This work is the result of a laboratory activity performed in Radiological Sciences Laboratory (CRL), linked to the State University of Rio de Janeiro (UERJ). This practice aimed to determine the absorbed dose to water, through the primary calibration method called dosimetry Fricke, which consists of ferrous ions (Fe + 2) to ferric (Fe + 3), generated by water radiolysis products which is the structural change of water molecule caused by ionizing radiation. A spectrophotometer was used to extract data for analysis at a wavelength (λ) 304 and 224 nm with function of measuring the absorbance using bottles with irradiated and nonirradiated Fricke solution. (author)

  5. The Effects on Absorbed Dose Distribution in Intraoral X-ray Imaging When Using Tube Voltages of 60 and 70 kV for Bitewing Imaging

    Directory of Open Access Journals (Sweden)

    Kristina Hellén-Halme

    2013-10-01

    Full Text Available Objectives: Efforts are made in radiographic examinations to obtain the best image quality with the lowest possible absorbed dose to the patient. In dental radiography, the absorbed dose to patients is very low, but exposures are relatively frequent. It has been suggested that frequent low-dose exposures can pose a risk for development of future cancer. It has previously been reported that there was no significant difference in the diagnostic accuracy of approximal carious lesions in radiographs obtained using tube voltages of 60 and 70 kV. The aim of this study was, therefore, to evaluate the patient dose resulting from exposures at these tube voltages to obtain intraoral bitewing radiographs.Material and Methods: The absorbed dose distributions resulting from two bitewing exposures were measured at tube voltages of 60 and 70 kV using Gafchromic® film and an anatomical head phantom. The dose was measured in the occlusal plane, and ± 50 mm cranially and caudally to evaluate the amount of scattered radiation. The same entrance dose to the phantom was used. The absorbed dose was expressed as the ratio of the maximal doses, the mean doses and the integral doses at tube voltages of 70 and 60 kV.Results: The patient receives approximately 40 - 50% higher (mean and integral absorbed dose when a tube voltage of 70 kV is used.Conclusions: The results of this study clearly indicate that 60 kV should be used for dental intraoral radiographic examinations for approximal caries detection.

  6. RBE/absorbed dose relationship of d(50)-Be neutrons determined for early intestinal tolerance in mice

    International Nuclear Information System (INIS)

    Gueulette, J.; Wambersie, A.

    1978-01-01

    RBE/absorbed dose relationship of d(50)-Be neutrons (ref.: 60 Co) was determined using intestinal tolerance in mice (LD50) after single and fractionated irradiation. RBE is 1.8 for a single fraction (about 1000 rad 60 Co dose); it increases when decreasing dose and reaches the plateau value of 2.8 for a 60 Co dose of about 200 rad. This RBE value is used for the clinical applications with the cyclotron 'Cyclone' at Louvain-la-Neuve [fr

  7. On the absorbed dose determination method in high energy electrons beams

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Oane, M.; Mitru, E.; Avadanei, C.

    2008-01-01

    The absorbed dose determination method in water for electron beams with energies in the range from 1 MeV to 50 MeV is presented herein. The dosimetry equipment for measurements is composed of an UNIDOS.PTW electrometer and different ionization chambers calibrated in air kerma in a Co 60 beam. Starting from the code of practice for high energy electron beams, this paper describes the method adopted by the secondary standard dosimetry laboratory (SSDL) in NILPRP - Bucharest

  8. The measurement of exposure rate and absorbed dose for photons of 6 to 7 MeV

    International Nuclear Information System (INIS)

    Birchall, I.

    1978-01-01

    Using the 16 N source at the Universities Reactor Centre, which provides a source of high energy photons of 6 and 7 MeV, experiments have been carried out to provide a calibration point for secondary standard and general survey instruments. The source was designed primarily for shielding experiments and suffers from a number of disadvantages if precise dose or exposure data are required. In particular the exposure rate is low, the source is physically large and the energy spectrum is contaminated with lower energy photons. A summary of the basic techniques is given because of the inherent difficulties in dose measurements particularly for high energy photons. (author)

  9. Quality control of diagnostic radiology to reduce absorbed dose of patients in Iran

    International Nuclear Information System (INIS)

    Aghahadi, Bahman.

    1996-01-01

    In order to reduce absorbed dose, to increase the image quality and to reduce the numbers of rejected films various quality control parameters were applied to X ray machines. These parameter are Kilo Volt peak, Milli Ampere, Exposure Time Focal Film Distance, Inherent Filters, Additional Filters Half Value Layer, Processor Condition, Cassettes. To evaluate and to apply these parameters in diagnostic radiological centers, ten hospitals were selected and a total number of 12 X ray machines were kept under quality control program. Considering different kinds of diagnostic radiology examination and to compare the dose before and after implementation of a quality control program, two kinds of examinations include in chest and abdomen examinations were considered. For each X ray machine, ten patients and for all selected centers, 120 patients were selected for chest examination and 120 patients for abdomen examinations; before and after implementation of quality control program, a total of 480 patients were selected randomly to be controlled. Base on different examinations carried out, it was concluded that both exposure conditions and general situations in radiological centers were not acceptable. The dosimetry results show that the average ski dose for chest and abdomen examinations were 0.28 m Gy and 4.23 Gy respectively. Before implementation of quality control step to reduce the surface skin dose, quality control parameters were applied and the exposure conditions were imposed. On average the absorbed doses for chest and abdomen examination were decreased to 79% and 61% respectively after the implementation of the program. From dose reduction point of view, the results of a part of this project which made by co-operation of International Atomic Energy Agency showed that Iran acquired the first grade for chest examination and second grade for abdomen examination. Base on the results obtained, the number of patients under chest and abdomen examination were 4041588 and

  10. LiF thermoluminescence dosimetry for mapping absorbed dose distributions in the gamma ray disinfection of machine-baled sheep wool

    International Nuclear Information System (INIS)

    Dexi Jiang

    1985-01-01

    The measurement of absorbed dose distributions of 60 Co γ-rays in machine-baled sheep wool, which is disinfected of certain parasitic bacteria (e.g. Brucella bacilli) by γ-ray treatment, is summarized. The preparation and main physical properties of the LiF-TLD are described, as well as the shape, structure and the activity of the 60 Co source and typical dose distributions measured around the source in free air. The results of dose distributions measured by the LiF-TLD agreed within +-5% with those given by a calibrated ionization chamber. The exposure rates (units R/min) at three typical measurement points inside a bale of sheep's wool were found to be quite uniform: centre 3.8x10 3 (+-2.1%); upper region 3.9x10 3 (+-2.4%); lower region 3.9x10 3 (+-1.9%). (author)

  11. Discrimination of various contributions to the absorbed dose in BNCT: Fricke-gel imaging and intercomparison with other experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G. E-mail: grazia.gambarini@mi.infn.it; Agosteo, S.; Marchesi, P.; Nava, E.; Palazzi, P.; Pecci, A.; Rosi, G.; Tinti, R

    2000-11-15

    A method is described for the 3D measurements of absorbed dose in a ferrous sulphate gel phantom, exposed in the thermal column of a nuclear reactor. The method, studied for Boron Neutron Capture Therapy (BNCT) purposes, allows absorbed dose imaging and profiling, with the separation of different contributions coming from different secondary radiations, generated from thermal neutrons. In fact, the biological effectiveness of the different radiations is different. Tests with conventional dosimeters were performed too.

  12. Monte Carlo dosimetric characterization of the Flexisource Co-60 high-dose-rate brachytherapy source using PENELOPE.

    Science.gov (United States)

    Almansa, Julio F; Guerrero, Rafael; Torres, Javier; Lallena, Antonio M

    60 Co sources have been commercialized as an alternative to 192 Ir sources for high-dose-rate (HDR) brachytherapy. One of them is the Flexisource Co-60 HDR source manufactured by Elekta. The only available dosimetric characterization of this source is that of Vijande et al. [J Contemp Brachytherapy 2012; 4:34-44], whose results were not included in the AAPM/ESTRO consensus document. In that work, the dosimetric quantities were calculated as averages of the results obtained with the Geant4 and PENELOPE Monte Carlo (MC) codes, though for other sources, significant differences have been quoted between the values obtained with these two codes. The aim of this work is to perform the dosimetric characterization of the Flexisource Co-60 HDR source using PENELOPE. The MC simulation code PENELOPE (v. 2014) has been used. Following the recommendations of the AAPM/ESTRO report, the radial dose function, the anisotropy function, the air-kerma strength, the dose rate constant, and the absorbed dose rate in water have been calculated. The results we have obtained exceed those of Vijande et al. In particular, the absorbed dose rate constant is ∼0.85% larger. A similar difference is also found in the other dosimetric quantities. The effect of the electrons emitted in the decay of 60 Co, usually neglected in this kind of simulations, is significant up to the distances of 0.25 cm from the source. The systematic and significant differences we have found between PENELOPE results and the average values found by Vijande et al. point out that the dosimetric characterizations carried out with the various MC codes should be provided independently. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  13. Absorbed dose calculation from beta and gamma rays of 131I in ellipsoidal thyroid and other organs of neck with MCNPX code

    Directory of Open Access Journals (Sweden)

    Mohammad Mirzaie

    2012-09-01

    Full Text Available Background: The 131I radioisotope is used for diagnosis and treatment of hyperthyroidism and thyroid cancer. In optimized Iodine therapy, a specific dose must be reached to the thyroid gland with minimum radiation to the cervical spine, cervical vertebrae, neck tissue, subcutaneous fat and skin. Dose measurement inside the alive organ is difficult therefore the aim of this research was dose calculation in the organs by MCNPX code. Materials and Methods: First of all, the input file for MCNPX code has been prepared to calculate F6 and F8 tallies for ellipsoidal thyroid lobes with long axes is tow times of short axes which the 131I is distributed uniformly inside the lobes. Then the code has been run for F6 and F8 tallies for variation of lobe volume from 1 to 25 milliliters. From the output file of tally F6, the gamma absorbed dose in ellipsoidal thyroid, spinal neck, neck bone, neck tissue, subcutaneous fat layer and skin for the volume lobe variation from 1 ml to 25 ml have been derived and the graphs are drew. As well as, form the output of F8 tally the absorbed energy of beta in thyroid and soft tissue of neck is obtained and listed in the table and then absorbed dose of bate has been calculated. Results: The results of this research show that for constant activity in thyroid, the absorbed dose of gamma decreases about 88.3% in thyroid, 6.9% at soft tissue, 19.3% in adipose layer and 17.4% in skin, but it increases 32.1% in spinal of neck and 32.3% in neck bone when the lobe volume varied from 1 to 25 milliliters. For the same situation, the beta absorbed dose decreases 95.9% in thyroid and 64.2% in soft tissue. Conclusion: For the constant activity in thyroid by increasing the thyroid volume, absorbed dose of gamma in thyroid and soft tissue of neck, adipose layer under the skin and skin of neck decreased, but it increased at spinal of neck and neck bone. Also, by increasing of the lobe volume in constant activity, the beta absorbed dose

  14. SU-F-207-05: Excess Heat Corrections in a Prototype Calorimeter for Direct Realization of CT Absorbed Dose to Phantom

    International Nuclear Information System (INIS)

    Chen-Mayer, H; Tosh, R

    2015-01-01

    Purpose: To reconcile air kerma and calorimetry measurements in a prototype calorimeter for obtaining absorbed dose in diagnostic CT beams. While corrections for thermal artifacts are routine and generally small in calorimetry of radiotherapy beams, large differences in relative stopping powers of calorimeter materials at the lower energies typical of CT beams greatly magnify their effects. Work-to-date on the problem attempts to reconcile laboratory measurements with modeling output from Monte Carlo and finite-element analysis of heat transfer. Methods: Small thermistor beads were embedded in a polystyrene (PS) core element of 1 cm diameter, which was inserted into a cylindrical HDPE phantom of 30 cm diameter and subjected to radiation in a diagnostic CT x-ray imaging system. Resistance changes in the thermistors due to radiation heating were monitored via lock-in amplifier. Multiple 3-second exposures were recorded at 8 different dose-rates from the CT system, and least-squares fits to experimental data were compared to an expected thermal response obtained by finite-element analysis incorporating source terms based on semi-empirical modeling and Monte Carlo simulation. Results: Experimental waveforms exhibited large thermal artifacts with fast time constants, associated with excess heat in wires and glass, and smaller steps attributable to radiation heating of the core material. Preliminary finite-element analysis follows the transient component of the signal qualitatively, but predicts a slower decay of temperature spikes. This was supplemented by non-linear least-squares fits incorporating semi-empirical formulae for heat transfer, which were used to obtain dose-to-PS in reasonable agreement with the output of Monte Carlo calculations that converts air kerma to absorbed dose. Conclusion: Discrepancies between the finite-element analysis and our experimental data testify to the very significant heat transfer correction required for absorbed dose calorimetry of

  15. SU-F-207-05: Excess Heat Corrections in a Prototype Calorimeter for Direct Realization of CT Absorbed Dose to Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Chen-Mayer, H; Tosh, R [NIST, Gaithersburg, MD (United States)

    2015-06-15

    Purpose: To reconcile air kerma and calorimetry measurements in a prototype calorimeter for obtaining absorbed dose in diagnostic CT beams. While corrections for thermal artifacts are routine and generally small in calorimetry of radiotherapy beams, large differences in relative stopping powers of calorimeter materials at the lower energies typical of CT beams greatly magnify their effects. Work-to-date on the problem attempts to reconcile laboratory measurements with modeling output from Monte Carlo and finite-element analysis of heat transfer. Methods: Small thermistor beads were embedded in a polystyrene (PS) core element of 1 cm diameter, which was inserted into a cylindrical HDPE phantom of 30 cm diameter and subjected to radiation in a diagnostic CT x-ray imaging system. Resistance changes in the thermistors due to radiation heating were monitored via lock-in amplifier. Multiple 3-second exposures were recorded at 8 different dose-rates from the CT system, and least-squares fits to experimental data were compared to an expected thermal response obtained by finite-element analysis incorporating source terms based on semi-empirical modeling and Monte Carlo simulation. Results: Experimental waveforms exhibited large thermal artifacts with fast time constants, associated with excess heat in wires and glass, and smaller steps attributable to radiation heating of the core material. Preliminary finite-element analysis follows the transient component of the signal qualitatively, but predicts a slower decay of temperature spikes. This was supplemented by non-linear least-squares fits incorporating semi-empirical formulae for heat transfer, which were used to obtain dose-to-PS in reasonable agreement with the output of Monte Carlo calculations that converts air kerma to absorbed dose. Conclusion: Discrepancies between the finite-element analysis and our experimental data testify to the very significant heat transfer correction required for absorbed dose calorimetry of

  16. Verification of absorbed dose calculation with XIO Radiotherapy Treatment Planning System

    International Nuclear Information System (INIS)

    Bokulic, T.; Budanec, M.; Frobe, A.; Gregov, M.; Kusic, Z.; Mlinaric, M.; Mrcela, I.

    2013-01-01

    Modern radiotherapy relies on computerized treatment planning systems (TPS) for absorbed dose calculation. Most TPS require a detailed model of a given machine and therapy beams. International Atomic Energy Agency (IAEA) recommends acceptance testing for the TPS (IAEA-TECDOC-1540). In this study we present customization of those tests for measurements with the purpose of verification of beam models intended for clinical use in our department. Elekta Synergy S linear accelerator installation and data acquisition for Elekta CMS XiO 4.62 TPS was finished in 2011. After the completion of beam modelling in TPS, tests were conducted in accordance with the IAEA protocol for TPS dose calculation verification. The deviations between the measured and calculated dose were recorded for 854 points and 11 groups of tests in a homogenous phantom. Most of the deviations were within tolerance. Similar to previously published results, results for irregular L shaped field and asymmetric wedged fields were out of tolerance for certain groups of points.(author)

  17. Mapping the terrestrial air-absorbed gamma dose rate based on the data of airborne gamma-ray spectrometry in southern cities of China

    International Nuclear Information System (INIS)

    Xiong Shengqing; Fan Zhengguo; Wu Qifan; Wan Jianhua; Wang Nanping; Chu Xingming; Pei Shaoying; Zeng Lihui

    2012-01-01

    An environmental radioactivity survey by Airborne Gamma-ray Spectrometry (AGS) on a large scale was undertaken in Zhuhai Zone (ZZ) and Shenzhen Zone (SZ), which include major cities in southern China, covering areas of 3800 km 2 and 4660 km 2 , respectively. The estimated dose rates by AGS have been compared with observed results by ionization chamber and portable dosemeter. Maps of the terrestrial dose rate at 1m above ground level have been calculated based on the data of AGS. The mean dose rates are 84.37 ± 51.69 and 82.10 ± 32.98 nGy/h in ZZ and SZ, and the maximum rates are 343.11 and 368.36 nGy/h, respectively. Dose rates in some places are above 180 nGy/h; the areas covered where 149 km 2 in ZZ and 43 km 2 in SZ. The dominant geological conditions that evidently contribute to the radioactive anomalies are outcrops of Middle and Late Jurassic and Cretaceous biotitic-granite. The growth of industrialization and urbanization has dramatically altered radiation background. Stone mining results in the increase of radiation levels with maximum dose rates approaching 368.36 nGy/h in an open pit. The investigation results provide valuable background data and give a good example for mapping nationwide natural radiation terrestrial dose rates in China by AGS. (author)

  18. Dose-rate and the reciprocity law: TL response of Ge-doped SiO2 optical fibers at therapeutic radiation doses

    International Nuclear Information System (INIS)

    Abdul Rahman, A.T.; Nisbet, A.; Bradley, D.A.

    2011-01-01

    An investigation has been made on commercially available Ge-doped SiO 2 optical fibers as a novel thermoluminescence system for radiotherapy dosimetry. This dosimeter has previously been shown by the group to provide sensitive dosimetry over a wide range of electron and photon dose, suitable for the needs of radiotherapy. In addition the optical fiber offers small physical size (125 μm diameter) and hence high spatial resolution. The reciprocity between thermoluminescence (TL) yield of Ge-doped SiO 2 optical fibers and dose has been investigated for fixed radiation dose for a range of photon and electron dose rates. For electron beams of nominal energies in the range of 9-20 MeV, we have investigated the TL response of these fibers for dose rates between 100 and 1000 cGy min -1 . For photon beams of nominal energies in the range of 6-15 MV, we have used dose rates of 100-600 cGy min -1 . Reproducibility and fading at fixed absorbed dose (3 Gy) and dose rate for the optical fibers were also investigated. At fixed dose rates, the TL optical fibers were found to produce a flat TL yield within 4% (1σ) and 3% (1σ) for electron and photon beams, respectively. The optical fibers demonstrated good reproducibility (±1.5%), low residual signal for a readout temperature of 300 o C and negligible fading. A weak dependence on dose-rate has been observed in the range of 3.4-3.9% for electrons (with an associated uncertainty of 4%) and 2.4-2.9% for photons (with an associated uncertainty of <4%). For electron and photon energies we note a consistent trend towards lower response in the TL yield of between 3.4-3.9% and 2.4-2.7%, respectively, at the higher dose rates in comparison with the response at lower dose rates. In addition we note an appreciable systematic energy dependence for both electron and photon beams. It is important to take such factors into account for providing precise and accurate radiotherapy dosimetry. It is also apparent that the optical fibers can be re

  19. Tank Z-361 dose rate calculations

    International Nuclear Information System (INIS)

    Richard, R.F.

    1998-01-01

    Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses

  20. Study of the influence of gold particles on the absorbed dose in soft tissue using polymer gel dosimetry

    International Nuclear Information System (INIS)

    Afonso, Luciana Caminha

    2011-01-01

    The presence of high-Z material adjacent to soft tissue, when submitted to irradiation, enhances locally the absorbed dose in these soft tissues. Such effect occurs due to the outscattering of photoelectrons from the high-Z material. Polymer gel dosimeters have been used to investigate this effect. Analytic calculations to estimate the dose enhancement and Monte Carlo simulations have been performed. Samples containing polymer gel (PG) with 0.005 gAu/gPG and pure polymer gel have been irradiated using an X-rays beam produced by 150 kV, filtered with 4 mm Al and 5 mm Cu, which resulted in an approximately 20% higher absorbed dose in the samples with gold in comparison to those with pure polymer gel. The analytic calculations and the Monte Carlo simulation resulted in a dose enhancement factor of approximately 30%. (author)

  1. Method to stimulate dose gradient in liquid media

    International Nuclear Information System (INIS)

    Scarlat, F.

    1993-01-01

    The depth absorbed dose from electrons with energy higher than 10 MeV shows a distribution with a big-percentage absorbed dose at the entrance surface and a small dose gradient. This is due to the big distance between the virtual focus and irradiated liquid medium. In order to stimulate dose gradient and decrease the surface dose, this paper presents a method for obtaining the second focus by means of a magnetostatic planar wiggler. Preliminary calculations indicated that the absorbed dose rate increases two-three times at the reference plane in the irradiated liquid medium. (Author)

  2. Level of natural radiation and doses to population in Shanxi province

    International Nuclear Information System (INIS)

    Yang Yi; Hao Hailiang; Wang Quanlu

    1985-01-01

    The exposure rates from natural radiation measured from August 1982 to January 1984 with a FD-71 Scintillation Radiometer in Shanxi Province are reported. The average absorbed dose rate in air of 1,842 open field sites was (10.78 +- 1.41) x 10 -8 Gy.h -1 . The mean value of area-weighted outdoor absorbed dose rates in air was 6.8 x 10 -8 Gy.h -1 . The average absorbed dose rate in air from natural external radiation of 3,446 indoor sites was (14.02 +- 2.09) x 10 -8 Gy.h -1 and the indoor area-weighted dose rate from natural radiation was 10.48 x 10 -8 Gy.h -1 . The annual individual average effective dose equivalant to population in this province was 0.88 mSv, and the annual collective dose equivalent was 21,626.83 man.Sv

  3. An approach to calculating absorbed doses to organs of high radiation sensitivity in diagnostic radioisotope examinations in vivo

    International Nuclear Information System (INIS)

    Staniszewska, M.A.; Jankowski, J.

    1984-01-01

    A method is presented of dose calculations for internal exposures of organ-sources and organ-targets. Variations of absorbed doses depending on sex and age of the patients investigated with the use of radionuclides are discussed. Definitions of the effective and collective dose equivalents are also given. 8 refs., 1 tab. (author)

  4. Bayesian estimation of dose rate effectiveness

    International Nuclear Information System (INIS)

    Arnish, J.J.; Groer, P.G.

    2000-01-01

    A Bayesian statistical method was used to quantify the effectiveness of high dose rate 137 Cs gamma radiation at inducing fatal mammary tumours and increasing the overall mortality rate in BALB/c female mice. The Bayesian approach considers both the temporal and dose dependence of radiation carcinogenesis and total mortality. This paper provides the first direct estimation of dose rate effectiveness using Bayesian statistics. This statistical approach provides a quantitative description of the uncertainty of the factor characterising the dose rate in terms of a probability density function. The results show that a fixed dose from 137 Cs gamma radiation delivered at a high dose rate is more effective at inducing fatal mammary tumours and increasing the overall mortality rate in BALB/c female mice than the same dose delivered at a low dose rate. (author)

  5. Consequences of the exposure at low dose rates-contribution of animal experimentation. Consequences de l'exposition aux faibles debits de dose. Apport de l'experimentation animale

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R. (CEA Centre d' Etudes de Fontenay-aux-Roses, 92 (FR). Direction des Sciences du Vivant)

    1990-01-01

    The exposure of laboratory animals to the various types of radiations will induce cancers in relation with the tissue absorbed doses. The shape of the dose-effet relationship is most variable. It is important to distinguish which tumours are comparable to human tumours. Those showing more analogies answer but seldom to the classical lineo-quadratic relationship; however, a strong attenuation of induction is demonstrated at low dose rates. Quasi-threshold relationships are seen after the exposure of some tissues to high-LET radiations. These observations question the validity of generalizing the radiobiologists' dual action theory, setting the origin of the dose-effect relationship in the induction of events within the DNA molecule. There is an alternative in the cellular collaboration events; it assumes that the effectiveness per dose unit decreases constantly as an inverse function of the dose rate.

  6. Functional results of radioiodine therapy with a 300-GY absorbed dose in Graves' disease

    Energy Technology Data Exchange (ETDEWEB)

    Willemsen, U.F. (Dept. of Nuclear Medicine, Dept. of Radiology, Muenchen (Germany)); Knesewitsch, P. (Dept. of Nuclear Medicine, Dept. of Radiology, Muenchen (Germany)); Kreisig, T. (Dept. of Nuclear Medicine, Dept. of Radiology, Muenchen (Germany)); Pickardt, C.R. (Dept. of Internal Medicine, Muenchen Univ. (Germany)); Kirsch, C.M. (Dept. of Nuclear Medicine, Dept. of Radiology, Muenchen (Germany))

    1993-11-01

    The aim of this study was to assess the results of high-dose radioiodine therapy given to 43 patients with recurrent hyperthyroidism due to Graves' disease between 1986 and 1992. We chose an intrathyroidal absorbed dose of 300 Gy and determined the applied activity individually, which ranged from 240 to 3120 MBq with a median of 752 MBq. Hperthyroidism was eliminated in 86% of cases after 3 months and in 100% after 12 months. No patient required a second radioiodine treatment. The incidnece of hyperthyroidism was 63% after 3 months and 93% after 18 months. Neither the pretherapeutic thyroid-stimulating immunoglobulin level nor the degree of co-existing endocrine ophthalmopathy was correlated with the time at which hypothyroidism developed. Patients with previous radioiodine therapy developed hypothyroidism earlier than patients with previous thyroid surgery. The results show that ablative radioiodine therapy with a 300-Gy absorbed dose is a very effective treatment of hyperthyroidism in Graves' disease, but it should be restricted to patients with recurrent hyperthyroidism combined with severe co-existing disorders or episodes of unfavourable reactions to antithyroid drugs. (orig.)

  7. Axial distribution of absorbed doses in fast neutron field at the RB reactor

    International Nuclear Information System (INIS)

    Sokcic-Kostic, M.; Pesic, M.; Antic, D.; Ninkovic, M.

    1988-11-01

    The coupled fast thermal system CFTS at the RB reactor is created for obtaining fast neutron fields. The axial distribution of fast neutron flux density in its second configuration (CFTS-2) is measured. The axial distribution of absorbed doses is computed on the basis of mentioned experimental results. At the end these experimental and computed results are given. (Author)

  8. Baseline studies of terrestrial outdoor gamma dose rate levels in Nigeria

    International Nuclear Information System (INIS)

    Farai, I.P.; Jibiri, N.N.

    2000-01-01

    The outdoor γ radiation exposure dose rates due to the radioactivity concentration of 40 K, 238 U and 232 Th in the soil across different environments in Nigeria have been carried out using the low-cost method of in situ γ ray spectrometry. Measurements were made in 18 cities, spread across the three major zones of the country. The radioactivity concentrations of these radionuclides in the soil were used to determine their γ radiation absorbed dose rates in the air. The range of average total dose rate due to the three radionuclides in the Eastern zone is between 0.025 and 0.081 μGy.h -1 with an average of 0.040 ± 0.006 μGy.h -1 , 0.041 and 0.214 μGy.h -1 with a mean of 0.089 ± 0.014 μGy.h -1 for the Western zone and between 0.066 and 0.222 μGy.h -1 with a mean of 0.102 ± 0.032 μGy.h -1 for the Northern zone. The average annual outdoor effective dose equivalents of 51 ± 8 μSv.y -1 , 114 ± 18 μSv.y -1 and 130 ± 41 μSv.y -1 have been estimated for the Eastern, Western and Northern zones, respectively. The average annual effective dose equivalent for the country has been estimated to be 98 ± 15 μSv.y -1 and the collective effective dose equivalent as 9.7 x 103 man.Sv.y -1 . Measurements have been taken as representing the baseline values of natural radioactivity as no artificial radionuclide was detected at any of the sites surveyed. (author)

  9. Dose rate effect on micronuclei induction in human blood lymphocytes exposed to single pulse and multiple pulses of electrons.

    Science.gov (United States)

    Acharya, Santhosh; Bhat, N N; Joseph, Praveen; Sanjeev, Ganesh; Sreedevi, B; Narayana, Y

    2011-05-01

    The effects of single pulses and multiple pulses of 7 MV electrons on micronuclei (MN) induction in cytokinesis-blocked human peripheral blood lymphocytes (PBLs) were investigated over a wide range of dose rates per pulse (instantaneous dose rate). PBLs were exposed to graded doses of 2, 3, 4, 6, and 8 Gy of single electron pulses of varying pulse widths at different dose rates per pulse, ranging from 1 × 10(6) Gy s(-1) to 3.2 × 10(8) Gy s(-1). Different dose rates per pulse were achieved by changing the dose per electron pulse by adjusting the beam current and pulse width. MN yields per unit absorbed dose after irradiation with single electron pulses were compared with those of multiple pulses of electrons. A significant decrease in the MN yield with increasing dose rates per pulse was observed, when dose was delivered by a single electron pulse. However, no reduction in the MN yield was observed when dose was delivered by multiple pulses of electrons. The decrease in the yield at high dose rates per pulse suggests possible radical recombination, which leads to decreased biological damage. Cellular response to the presence of very large numbers of chromosomal breaks may also alter the damage.

  10. Estimation of absorbed dose in cell nuclei due to DNA-bound /sup 3/H

    Energy Technology Data Exchange (ETDEWEB)

    Saito, M; Ishida, M R; Streffer, C; Molls, M

    1985-04-01

    The average absorbed dose due to DNA-bound /sup 3/H in a cell nucleus was estimated by a Monte Carlo simulation for a model nucleus which was assumed to be spheroidal. The volume of the cell nucleus was the major dose-determining factor for cell nuclei which have the same DNA content and the same specific activity of DNA. This result was applied to estimating the accumulated dose in the cell nuclei of organs of young mice born from mother mice which ingested /sup 3/H-thymidine with drinking water during pregnancy. The values of dose-modifying factors for the accumulated dose due to DNA-bound /sup 3/H compared to the dose due to an assumed homogenous distribution of /sup 3/H in organ were found to be between about 2 and 6 for the various organs.

  11. Factors affecting quality for beta dose rate measurements using ISO 6980 series I reference sources

    Energy Technology Data Exchange (ETDEWEB)

    Burns, R.E. Jr.; O`Brien, J.M. Jr. [Atlan-Tech, Rosewll, GA (United States)

    1993-12-31

    Atlan-Tech, Inc. has performed several calibrations of ISO 6980 Series 1 reference beta sources over the past two to three years. There were many problems encountered in attempting to compare the results of these calibrations with those from other laboratories, indicating the need for more standardization in the methodology employed for the measurement of the absorbed dose rate from ISO 6980 Series 1 reference beta sources. This document describes some of the problems encountered in attempting to intercompare results of beta dose-rate measurements. It proposes some solutions in an attempt to open a dialogue among facilities using reference beta standards for the purpose of promoting better measurement quality assurance through data intercomparison.

  12. Factors affecting quality for beta dose rate measurements using ISO 6980 series I reference sources

    International Nuclear Information System (INIS)

    Burns, R.E. Jr.; O'Brien, J.M. Jr.

    1993-01-01

    Atlan-Tech, Inc. has performed several calibrations of ISO 6980 Series 1 reference beta sources over the past two to three years. There were many problems encountered in attempting to compare the results of these calibrations with those from other laboratories, indicating the need for more standardization in the methodology employed for the measurement of the absorbed dose rate from ISO 6980 Series 1 reference beta sources. This document describes some of the problems encountered in attempting to intercompare results of beta dose-rate measurements. It proposes some solutions in an attempt to open a dialogue among facilities using reference beta standards for the purpose of promoting better measurement quality assurance through data intercomparison

  13. Efficacy of a radiation absorbing shield in reducing dose to the interventionalist during peripheral endovascular procedures: a single centre pilot study.

    Science.gov (United States)

    Power, S; Mirza, M; Thakorlal, A; Ganai, B; Gavagan, L D; Given, M F; Lee, M J

    2015-06-01

    This prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures. A commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated. TLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142). Initial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator's body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

  14. Calculation of dose conversion factors for doses in the fingernails to organ doses at external gamma irradiation in air

    International Nuclear Information System (INIS)

    Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.

    2015-01-01

    Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.

  15. Dose/dose-rate responses of shrimp larvae to UV-B radiation

    International Nuclear Information System (INIS)

    Damkaer, D.M.

    1981-01-01

    Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm -2 sub([DNA]) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm -2 sub([DNA]). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation. (orig.)

  16. Dose/dose-rate responses of shrimp larvae to UV-B radiation

    Energy Technology Data Exchange (ETDEWEB)

    Damkaer, D.M.; Dey, D.B.; Heron, G.A.

    1981-01-01

    Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm/sup -2/sub((DNA)) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm/sup -2/sub((DNA)). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation.

  17. Radiation absorbed doses from iron-52, iron-55, and iron-59 used to study ferrokinetics

    International Nuclear Information System (INIS)

    Robertson, J.S.; Price, R.R.; Budinger, T.F.; Fairbanks, V.F.; Pollycove, M.

    1983-01-01

    Biological data obtained principally with Fe-59 citrate are used with physical data to calculate radiation absorbed doses for ionic or weak chelate forms of Fe-52, Fe-55, and Fe-59, administered by intravenous injection. Doses are calculated for normal subjects, primary hemochromatosis (also called idiopathic or hereditary hemochromatosis), pernicious anemia in relapse, iron-deficiency anemia, and polycythemia vera. The Fe-52 doses include the dose from the Mn-52m daughter generated after injection of Fe-52. Special attention has been given to the dose to the spleen, which has a relatively high concentration of RBCs and therefore of radioiron, and which varies significantly in size in both health and disease

  18. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    International Nuclear Information System (INIS)

    Blaylock, B.G.; Frank, M.L.; O'Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h -1 (1 rad d -1 ). A dose rate no greater than 0.4 mGy h -1 to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h -1 will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted

  19. Electron absorbed dose comparison between MCNP5 and Penelope Monte Carlo code for microdosimetry

    International Nuclear Information System (INIS)

    Cintra, Felipe B. de; Yoriyaz, Helio

    2009-01-01

    The objective of the present work was to compare electron absorbed dose results between two widespread used codes in international scientific community: MCNP5 and Penelope-2003. Individual water spheres with masses between 10 -9 g up to 10 -3 g immersed in an infinite water medium (density of 1g/cm 3 ) and monoenergetic electron sources with energy from 0.002 MeV to 0.1 MeV have been considered. The absorbed dose in the spheres was evaluated by both codes and the relative differences have been quantified. The results shown that Penelope gives, in general, higher results that, in some cases saturate or reach a maximum point and then rapidly drops. Particularly, for the 40 keV electron source we have done additional tests in three different scenarios: more points in the region of lower masses to a better definition of the curve behavior; MCNP used 200 substeps and Penelope was set to a full detail history methodology, and almost same parameters of case B but with the density of exterior medium increased to 10 g/cm 3 . The three cases show the influence of the backscattering that contribute with an important fraction of absorbed dose, finally we can infer a range of reliability to use the codes in this kind of simulations: both codes can calculate close results for up to 10 -4 g.Even though MCNP5 uses the condensed history method, if simulation parameters are chosen carefully it can reproduce results very close to those obtained using detailed history mode. In some cases, the use of higher number of electron substeps causes significant differences in the result. (author)

  20. Estimation of absorbed dose for 2-[F-18]fluoro-2-deoxy-d- glucose using whole-body positron emission tomography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Deloar, H.M.; Fujiwara, Takehiko; Shidahara, Miho; Nakamura, Takashi; Watabe, Hiroshi; Narita, Yuichiro; Itoh, Masatoshi; Miyake, Masayasu; Watanuki, Shoichi

    1998-01-01

    The purpose of this study was to measure the cumulated activity and absorbed dose in organs after i.v. administration of 18 F-FDG using whole-body PET and MRI. Whole-body dynamic emission scans for 18 F-FDG were performed in six normal volunteers after transmission scans. The total activity of a source organ was obtained from the activity concentration of the organ measured by whole-body PET and the volume of that organ measured by whole-body T1-weighted MRI. The cumulated activity of each source organ was calculated from the time-activity curve. Absorbed doses to the individuals were estimated by the MIRD (medical internal radiation dosimetry) method. Another calculation of cumulated activities and absorbed doses was performed using the organ volumes from the MIRD phantom and the ''Japanese reference man'' to investigate the discrepancy of actual individual results against the phantom results. The cumulated activities of 18 source organs were calculated, and absorbed doses of 27 target organs estimated. Among the target organs, bladder wall, brain and kidney received the highest doses for the above three sets of organ volumes. Using measured individual organ volumes, the average absorbed doses for those organs were found to be 3.1 x 10 -1 , 3.7 x 10 -2 and 2.8 x 10 -2 mGy/MBq, respectively. The mean effective doses in this study for individuals of average body weight (64.5 kg) and the MIRD phantom of 70 kg were the same, i.e. 2.9 x 10 -2 mSv/MBq, while for the Japanese reference man of 60 kg the effective dose was 2.1 x 10 -2 mSv/MBq. The results for measured organ volumes derived from MRI were comparable to those obtained for organ volumes from the MIRD phantom. Although this study considered 18 F-FDG, combined use of whole-body PET and MRI might be quite effective for improving the accuracy of estimations of the cumulated activity and absorbed dose of positron-labelled radiopharmaceuticals.(orig./MG) (orig.)

  1. Evaluation of the dose absorbed by the thyroid of patients undergoing treatment of Graves disease;Avaliacao da dose absorvida pela tireoide de pacientes submetidos ao tratamento da doenca de Graves

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Tiago L.; Filho, Joao A. [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil). Dept. de Fisica; Silva, Jose M.F. da [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2009-07-01

    The radioiodine is used as complementary treatment of thyroid cancer and as first choice for the treatment of Graves' disease, being efficient, safe and easy administration, but without there is a protocol defined. This work was evaluated the thyroid absorbed dose from its mass and maximum uptake of I-131 obtained in the examination of diagnostic radiology of radiotherapeutic patients undergoing treatment of Graves' disease. Based on the results, it is observed that the thyroid absorbed dose, as much in terms of mass as the maximum uptake of I-131 for different values of administered activity, varies significantly. The analysis of these parameters is an excellent indicator for the pre-define quantity of radionuclide that is administered to the patient in terms of the radiation dose required to achieve an efficient therapeutic treatment. Moreover, it was observed that the thyroid absorbed dose depends on the degree of pathology of the disease, its mass and of the maximum uptake of I-131. (author)

  2. Absorbed doses and energy imparted from radiographic examination of velopharyngeal function during speech

    International Nuclear Information System (INIS)

    Isberg, A.; Julin, P.; Kraepelien, T.; Henrikson, C.O.

    1989-01-01

    Absorbed doses of radiation were measured by thermoluminescent dosimeters (TLDs) using a skull phantom during simulated cinefluorographic and videofluorographic examination of velopharyngeal function in frontal and lateral projections. Dosages to the thyroid gland, the parotid gland, the pituitary gland, and ocular lens were measured. Radiation dosage was found to be approximately 10 times less for videofluoroscopy when compared with that of cinefluoroscopy. In addition, precautionary measures were found to reduce further the exposure of radiation-sensitive tissues. Head fixation and shielding resulted in dose reduction for both video- and cinefluoroscopy. Pulsing exposure for cinefluoroscopy also reduced the dosage

  3. Absorbed and effective dose from spiral and computed tomography for the dental implant planning

    International Nuclear Information System (INIS)

    Hong, Beong Hee; Han, Won Jeong; Kim, Eun Kyung

    2001-01-01

    To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. For radiographic projection. TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophages. Effective dose was calculated, using the method suggested by Frederiksen at al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning

  4. Radiation absorbed dose estimate for Rb-82 using in vivo measurements in man

    International Nuclear Information System (INIS)

    Ryan, J.; Harper, P.; Stark, V.; Peterson, E.; Lathrop, K.

    1984-01-01

    Radiation absorbed doses from intravenous Rb-82 (t 1/2 = 75 sec) were calculated by conjugate counting in 2 healthy adult men aged 27 and 23. Following an i.v. injection of a carefully calibrated amount of Rb-82, an organ of interest was imaged with a gamma camera equipped with a rotating tungsten collimator and data were collected in 10 second frames. Counts in the region of interest were corrected for adjacent background. Imaging was repeated from the opposite side of the body after a second injection. A calibrated reference source of Ge-68 placed on the body over the organ was similarly imaged in the absence of the rubidium activity. The integrated time activity curve in uCi-hours was obtained by comparing the observed kidney net conjugate counts with the reference source conjugate counts which represented a known number of uCi-hours. The organ self doses to the kidneys, liver, lungs, heart, and testes were determined by this technique which eliminated the effects of attenuation. Total absorbed doses to organs from all sources were calculated using the MIRD formulation and the averages of the 2 determinations (mrads/mCi) are as follows: heart (walls) 6.6; kidneys 31.3; liver 4.4; lungs 7.3; testes (1 subject only) 2.4; red marrow 1.7; and whole body 1.9. The highest dose is to the kidneys, but in an older subject (68 yr old man) the measured self dose to the left kidney was 16 mrads/mCi. These data are consistent with the decline in renal blood flow which occurs with increasing age and decreases renal exposure in older patients at increased risk of acute coronary disease who undergo myocardial perfusion imaging with Rb-82

  5. Dose of Biocoagulant-Mixing Rate Combinations for Optimum Reduction of COD in Wastewater

    Science.gov (United States)

    Patricia, Maria Faustina; Purwono; Budihardjo, Mochamad Arief

    2018-02-01

    Chemical oxygen demand (COD) in domestic wastewater can be treated using flocculation-coagulation process with addition of Oyster mushroom (Pleurotus ostreatus) in powder form as biocoagulant. The fungal cell wall of Oyster mushroom comprises of chitin that is high polyelectrolyte and can be function as an absorbent of heavy metals in wastewater. The effectiveness of flocculation-coagulation process in treating wastewater depends on dose of coagulant and mixing rate. Therefore, this study aims to determine the best combination of three variation of dose of biocoagulant which are 600 mg/l, 1000 mg/l, and 2000 mg/l and mixing rate which are 100 rpm, 125 rpm, and 150 rpm that give the most reduction of COD in the wastewater. The result indicates that the combination of 1000 mg/l of biocoagulant and 100 rpm of mixing rate were found to be the most optimum combination to treat COD in the wastewater with COD reduction of 47.7%.

  6. Dose of Biocoagulant-Mixing Rate Combinations for Optimum Reduction of COD in Wastewater

    Directory of Open Access Journals (Sweden)

    Faustina Patricia Maria

    2018-01-01

    Full Text Available Chemical oxygen demand (COD in domestic wastewater can be treated using flocculation-coagulation process with addition of Oyster mushroom (Pleurotus ostreatus in powder form as biocoagulant. The fungal cell wall of Oyster mushroom comprises of chitin that is high polyelectrolyte and can be function as an absorbent of heavy metals in wastewater. The effectiveness of flocculation-coagulation process in treating wastewater depends on dose of coagulant and mixing rate. Therefore, this study aims to determine the best combination of three variation of dose of biocoagulant which are 600 mg/l, 1000 mg/l, and 2000 mg/l and mixing rate which are 100 rpm, 125 rpm, and 150 rpm that give the most reduction of COD in the wastewater. The result indicates that the combination of 1000 mg/l of biocoagulant and 100 rpm of mixing rate were found to be the most optimum combination to treat COD in the wastewater with COD reduction of 47.7%.

  7. Absorbed doses received by patients submitted to chest radiographs in hospitals of the city of Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Freitas, Marcelo Baptista de

    2000-01-01

    Medical irradiation contributes with a significant amount to the dose received by the population. Here, this contribution was evaluated in a survey of absorbed doses received by patients submitted to chest radiological examinations (postero-anterior (PA) and lateral (LAT) projections) in hospitals of the city of Sao Paulo. Due to the variety of equipment and procedures used in radiological examinations, a selection of hospitals was made (12, totalizing 27 X-ray facilities), taking into account their representativeness as medical institutions in the city, in terms of characteristics and number of radiographs carried out. An anthropomorphic phantom, provided with thermoluminescent dosemeters (TLD-1 00), was irradiated simulating the patient, and the radiographic image quality was evaluated. Absorbed doses were determined to the thoracic region (entrance and exit skin and lung doses), and to some important organs from the radiation protection point of view (lens of the eye, thyroid and gonads). The great variation on the exposure parameters (kV, mA.s, beam size) leads to a large interval of entrance skin doses-ESD (coefficients of variation, CV, of 60% and 76%, for PA and LAT projections, respectively, were found) and of organ doses (CV of 60% and 46%. for thyroid and lung respectively). Mean values of ESD for LAT and PA projections were 0.22 and 0.98 mGy, respectively. The average absorbed doses per exam (PA and LAT) to thyroid and lung, 0.15 and 0.24 mGy respectively,showed that the thyroid was irradiated by the primary beam in many cases. Values of lens of the eye and gonad absorbed doses were below 30 μGy. Comparison of the lung doses obtained in this study with values in the literature, calculated by Monte Carlo simulation, showed good agreement. On the other hand, the comparison shows significant differences in the dose values to organs outside the chest region (thyroid, lens of eye and gonads). The effective dose calculated for a chest examination, PA and LAT

  8. Measurement of high dose rates of 60Co by gamma activation of115In and 111Cd foils

    International Nuclear Information System (INIS)

    Haddad, Kh; Qattan, M.; Taleb, A.

    2009-12-01

    The high gamma dose rate measurement technique using nuclear reaction (γ,(γ ' ') was introduced in this work. This technique is cheap, easy, reliable, and independent of chemical and physical factors, which affect other techniques. The response to the absorbed dose in this technique is linear and can be used for high dose. Cd and In foils were irradiated using 60 Co source and the resulted isomer activities were measured using gamma spectrometer. These foils were calibrated to be used as dosemeter and its results were compared with conventional one. The dose distribution in the irradiation field was determined using In foils. (authors)

  9. Magnetic Resonance Imaging-Based Radiation-Absorbed Dose Estimation of Ho-166 Microspheres in Liver Radioembolization

    NARCIS (Netherlands)

    Seevinck, Peter R.; van de Maat, Gerrit H.; de Wit, Tim C.; Vente, Maarten A. D.; Nijsen, Johannes F. W.; Bakker, Chris J. G.

    2012-01-01

    Purpose: To investigate the potential of magnetic resonance imaging (MRI) for accurate assessment of the three-dimensional Ho-166 activity distribution to estimate radiation-absorbed dose distributions in Ho-166-loaded poly (L-lactic acid) microsphere (Ho-166-PLLA-MS) liver radioembolization.

  10. Assessment of absorbed dose to the ovaries of patients undergoing pelvic CT examination

    Energy Technology Data Exchange (ETDEWEB)

    Tavakoli, H.M.B. [Isfahan Univ. of Medical Sciences (Iran, Islamic Republic of)

    2006-07-01

    Full text of publication follows: Introduction: Although Computed Tomography (CT) procedures constitute about 5% of the total diagnostic radiology procedures but are responsible for about 40% of the total ionizing radiation dose to the general population. As the dose is high especially in the CT of female pelvis, genetic radiation risk is also considerable. Materials and Methods: Radiation doses to the ovaries of the patients undergoing CT examination of the pelvis were measured from 9 different CT scanners available in Isfahan city. For each CT scanner 20 patients were selected. Measurement of organ dose was performed using TLD method. Results and Discussions: Mean and S.D. of absorbed dose to the ovaries from Shimadzo 2500 were 56.6 2.8; from GE Max 640 were 36.8 1.7; from GE Sytec 3000 were 36.6 1.8; from GE Sytec 4000 were 36.6 2.6; from Piker were 38.4 2.1; from Shimadzo 4500 were 36.4 1.2 and from Shimadzo 7800TE 28.2 1.5. Associated risks due to the measured dose are discussed. (author)

  11. Dose-rate and the reciprocity law: TL response of Ge-doped SiO{sub 2} optical fibers at therapeutic radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Abdul Rahman, A.T., E-mail: a.t.abdulrahman@surrey.ac.uk [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH, Surrey (United Kingdom); School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA Malaysia (UiTM), Campus of Negeri Sembilan, 72000 Kuala Pilah (Malaysia); Nisbet, A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH, Surrey (United Kingdom); Departments of Medical Physics, the Royal Surrey County Hospital (RSCH) NHS Trust, Edgerton Road, Guildford GU2 7XX, Surrey (United Kingdom); Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH, Surrey (United Kingdom)

    2011-10-01

    An investigation has been made on commercially available Ge-doped SiO{sub 2} optical fibers as a novel thermoluminescence system for radiotherapy dosimetry. This dosimeter has previously been shown by the group to provide sensitive dosimetry over a wide range of electron and photon dose, suitable for the needs of radiotherapy. In addition the optical fiber offers small physical size (125 {mu}m diameter) and hence high spatial resolution. The reciprocity between thermoluminescence (TL) yield of Ge-doped SiO{sub 2} optical fibers and dose has been investigated for fixed radiation dose for a range of photon and electron dose rates. For electron beams of nominal energies in the range of 9-20 MeV, we have investigated the TL response of these fibers for dose rates between 100 and 1000 cGy min{sup -1}. For photon beams of nominal energies in the range of 6-15 MV, we have used dose rates of 100-600 cGy min{sup -1}. Reproducibility and fading at fixed absorbed dose (3 Gy) and dose rate for the optical fibers were also investigated. At fixed dose rates, the TL optical fibers were found to produce a flat TL yield within 4% (1{sigma}) and 3% (1{sigma}) for electron and photon beams, respectively. The optical fibers demonstrated good reproducibility ({+-}1.5%), low residual signal for a readout temperature of 300 {sup o}C and negligible fading. A weak dependence on dose-rate has been observed in the range of 3.4-3.9% for electrons (with an associated uncertainty of 4%) and 2.4-2.9% for photons (with an associated uncertainty of <4%). For electron and photon energies we note a consistent trend towards lower response in the TL yield of between 3.4-3.9% and 2.4-2.7%, respectively, at the higher dose rates in comparison with the response at lower dose rates. In addition we note an appreciable systematic energy dependence for both electron and photon beams. It is important to take such factors into account for providing precise and accurate radiotherapy dosimetry. It is also

  12. Intensity of the absorbing dose of the gamma rays in the air of Krusevac during and after nuclear accident in Chernobil

    International Nuclear Information System (INIS)

    Fortuna, D.

    1997-01-01

    In this paper are compared overage daily values of the intensity of the absorbing doses of the gamma rays in the air of Krusevac, during and after nuclear accident in Cernobil. Average daily values of intensity of the absorbing doses of gamma rays in the air of Krusevac, immediately after nuclear accident in Cernobil were, three to seven time higher than of the average daily values of the natural rays. (author)

  13. Calculation of Absorbed Glandular Dose using a FORTRAN Program Based on Monte Carlo X-ray Spectra in Mammography

    Directory of Open Access Journals (Sweden)

    Ali Asghar Mowlavi

    2011-03-01

    Full Text Available Introduction: Average glandular dose calculation in mammography with Mo-Rh target-filter and dose calculation for different situations is accurate and fast. Material and Methods: In this research, first of all, x-ray spectra of a Mo target bombarded by a 28 keV electron beam with and without a Rh filter were calculated using the MCNP code. Then, we used the Sobol-Wu parameters to write a FORTRAN code to calculate average glandular dose. Results: Average glandular dose variation was calculated against the voltage of the mammographic x-ray tube for d = 5 cm, HVL= 0.35 mm Al, and different value of g. Also, the results related to average glandular absorbed dose variation per unit roentgen radiation against the glandular fraction of breast tissue for kV = 28 and HVL = 0.400 mmAl and different values of d are presented. Finally, average glandular dose against d for g = 60% and three values of kV (23, 27, 35 kV with corresponding HVLs have been calculated. Discussion and Conclusion: The absorbed dose computational program is accurate, complete, fast and user friendly. This program can be used for optimization of exposure dose in mammography. Also, the results of this research are in good agreement with the computational results of others.

  14. Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

    International Nuclear Information System (INIS)

    Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J.

    2015-01-01

    PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study

  15. Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J., E-mail: mlee@rcsi.ie [Beaumont Hospital, Imaging and Interventional Radiology Department (Ireland)

    2015-06-15

    PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

  16. 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)

  17. 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)

  18. MCNPX calculations of dose rate distribution inside samples treated in the research gamma irradiating facility at CTEx

    Energy Technology Data Exchange (ETDEWEB)

    Rusin, Tiago; Rebello, Wilson F.; Vellozo, Sergio O.; Gomes, Renato G., E-mail: tiagorusin@ime.eb.b, E-mail: rebello@ime.eb.b, E-mail: vellozo@cbpf.b, E-mail: renatoguedes@ime.eb.b [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Nuclear; Vital, Helio C., E-mail: vital@ctex.eb.b [Centro Tecnologico do Exercito (CTEx), Rio de Janeiro, RJ (Brazil); Silva, Ademir X., E-mail: ademir@con.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear

    2011-07-01

    A cavity-type cesium-137 research irradiating facility at CTEx has been modeled by using the Monte Carlo code MCNPX. The irradiator has been daily used in experiments to optimize the use of ionizing radiation for conservation of many kinds of food and to improve materials properties. In order to correlate the effects of the treatment, average doses have been calculated for each irradiated sample, accounting for the measured dose rate distribution in the irradiating chambers. However that approach is only approximate, being subject to significant systematic errors due to the heterogeneous internal structure of most samples that can lead to large anisotropy in attenuation and Compton scattering properties across the media. Thus this work is aimed at further investigating such uncertainties by calculating the dose rate distribution inside the items treated such that a more accurate and representative estimate of the total absorbed dose can be determined for later use in the effects-versus-dose correlation curves. Samples of different simplified geometries and densities (spheres, cylinders, and parallelepipeds), have been modeled to evaluate internal dose rate distributions within the volume of the samples and the overall effect on the average dose. (author)

  19. MCNPX calculations of dose rate distribution inside samples treated in the research gamma irradiating facility at CTEx

    International Nuclear Information System (INIS)

    Rusin, Tiago; Rebello, Wilson F.; Vellozo, Sergio O.; Gomes, Renato G.; Silva, Ademir X.

    2011-01-01

    A cavity-type cesium-137 research irradiating facility at CTEx has been modeled by using the Monte Carlo code MCNPX. The irradiator has been daily used in experiments to optimize the use of ionizing radiation for conservation of many kinds of food and to improve materials properties. In order to correlate the effects of the treatment, average doses have been calculated for each irradiated sample, accounting for the measured dose rate distribution in the irradiating chambers. However that approach is only approximate, being subject to significant systematic errors due to the heterogeneous internal structure of most samples that can lead to large anisotropy in attenuation and Compton scattering properties across the media. Thus this work is aimed at further investigating such uncertainties by calculating the dose rate distribution inside the items treated such that a more accurate and representative estimate of the total absorbed dose can be determined for later use in the effects-versus-dose correlation curves. Samples of different simplified geometries and densities (spheres, cylinders, and parallelepipeds), have been modeled to evaluate internal dose rate distributions within the volume of the samples and the overall effect on the average dose. (author)

  20. Absolute absorbed dose measurements with an array of ionization chambers as part of a routine procedure of quality control for the VMAT technique

    International Nuclear Information System (INIS)

    Clemente Gutierrez, F.; Cabello Murillo, E.; Ramirez Ros, J. C.; Casa de Julian, M. A. de la

    2011-01-01

    Arcotheraphy techniques volumetric modulated (VMAT) treatments involve continuous variation of the gantry rotation speed, positions of the sheets and dose rate. Since all treatments are administered by continuous arcs, these techniques require quality control procedures to ensure quick and easy constancy of the calibration factor (total absorbed dose) for any gantry angle. We report here a simple method of quality control for the measurement of the calibration factor using an array of ionization chambers. The measurements were performed on a unit of 6 MV Elekta Synergy with VMAT, belonging to the Radiation Oncology service of the Defense Central Hospital Gomez Ulla.

  1. Spontaneous mutation rates and the rate-doubling dose

    International Nuclear Information System (INIS)

    Von Borstel, R.C.; Moustaccki, E.; Latarjet, R.

    1978-01-01

    The amount of radiation required to double the frequency of mutations or tumours over the rate of those that occur spontaneously is called the rate-doubling dose. An equivalent concept has been proposed for exposure to other environmental mutagens. The doubling dose concept is predicated on the assumption that all human populations have the same spontaneous mutation rate, and that this spontaneous mutation rate is known. It is now established for prokaryotes and lower eukaryotes that numerous genes control the spontaneous mutation rate, and it is likely that the same is true for human cells as well. Given that the accepted mode of evolution of human populatons is from small, isolated groups of individuals, it seems likely that each population would have a different spontaneous mutation rate. Given that a minimum of twenty genes control or affect the spontaneous mutation rate, and that each of these in turn is susceptible to spontaneously arising or environmentally induced mutations, it seems likely that every individual within a population (except for siblings from identical multiple births) will have a unique spontaneous mutation rate. If each individual in a population does have a different spontaneous mutation rate, the doubling dose concept, in rigorous terms, is fallacious. Therefore, as with other concepts of risk evaluation, the doubling dose concept is subject to criticism. Nevertheless, until we know individual spontaneous mutation rates with precision, and can evaluate risks based on this information, the doubling dose concept has a heuristic value and is needed for practical assessment of risks for defined populations. (author)

  2. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice

    International Nuclear Information System (INIS)

    Ware, J.H.; Rusek, A.; Sanzari, J.; Avery, S.; Sayers, C.; Krigsfeld, G.; Nuth, M.; Wan, X.S.; Kennedy, A.R.

    2010-01-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  3. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice.

    Science.gov (United States)

    Ware, J H; Sanzari, J; Avery, S; Sayers, C; Krigsfeld, G; Nuth, M; Wan, X S; Rusek, A; Kennedy, A R

    2010-09-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  4. Review of techniques and detectors used in instruments for field measurement of beta doses and dose rates

    International Nuclear Information System (INIS)

    Jones, A.R.

    1983-01-01

    Generally, field measurements are required to assess the hazard from #betta#-rays before personnel are allowed to occupy a working space or perform a task. Occasionally, the measurements are required for an assessment after a #betta#-ray exposure is suspected to have occurred. Until recently the dose or dose rate have been the quantities of interest but there is now felt to be a need to characterize the energies and directions of the #betta#-rays as well. The purpose of #betta#-dosimetry is the assessment of hazard to superficial tissues (within approx. 10 mm of the surface) and that these tissues may also be exposed simultaneously to other ionizing radiations. The #betta#-dosimetry technique must take account of this. With these uses of field instruments in mind the following detectors, and associated techniques will be discussed in terms of the measurement principles, advantages and limitations: thin-walled ion chambers (sometimes in combination with thick-walled ones or with covers thick enough to prevent penetration of #betta#-particles); thin scintillators, nearly tissue equivalent, to provide a detector analogous to skin; scintillators, thick enough to absorb all the energy of the #betta#-particles (circuitry is required to count pulses according to size to permit calculation of dose or dose rate); silicon diodes with thin detection layers operated as photocurrent generators; silicon diodes, reversed biassed, with pulses counted according to size; and simple pulse counters (e.g., GM counters or silicon diodes with thin windows)

  5. Tumoral fibrosis effect on the radiation absorbed dose of 177Lu–Tyr3-octreotate and 177Lu–Tyr3-octreotate conjugated to gold nanoparticles

    International Nuclear Information System (INIS)

    Azorín-Vega, E.P.; Zambrano-Ramírez, O.D.; Rojas-Calderón, E.L.; Ocampo-García, B.E.; Ferro-Flores, G.

    2015-01-01

    The aim of this work was to evaluate the tumoral fibrosis effect on the radiation absorbed dose of the radiopharmaceuticals 177 Lu–Tyr 3 -octreotate (monomeric) and 177 Lu–Tyr 3 -octreotate–gold nanoparticles (multimeric) using an experimental HeLa cells tumoral model and the Monte Carlo PENELOPE code. Experimental and computer micro-environment models with or without fibrosis were constructed. Results showed that fibrosis increases up to 33% the tumor radiation absorbed dose, although the major effect on the dose was produced by the type of radiopharmaceutical (112 Gy-multimeric vs. 43 Gy-monomeric). - Highlights: • Fibrosis increases the radiation absorbed dose to the tumor. • Fibrosis increases the radiopharmaceutical residence time in the tumor. • The multimeric nature of the radiopharmaceuticals enhances the radiopharmaceutical retention

  6. Radiochromic Plastic Films for Accurate Measurement of Radiation Absorbed Dose and Dose Distributions

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Fidan, S.

    1977-01-01

    of dose rate (1–1014 rad s−1). Upon irradiation of the film, the profile of the radiation field is registered as a permanent colored image of the dose distribution. Unlike most other types of dyed plastic dose meters, the optical density produced by irradiation is in most cases stable for periods...... of many polymeric systems in industrial radiation processing. The result is that errors due to energy dependence of response of the radiation sensor are effectively reduced, since the spectral sensitivity of the dose meter matches that of the polymer of interest, over a wide range of photon and electron...

  7. Application of polystyrene - water calorimeter in determination of absorbed dose. Vol. 4.

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, F A [Nuclear Materials Authority, Maadi, Cairo (Egypt); Ashry, H A; El-Behay, A Z; Abdou, S [National Center, for Radiation Research and Technology, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The polystyrene-water calorimeter was investigated as a modification of the water calorimeter, where the polystyrene has a low specific heat and negligible known heat defect. This calorimeter was designed, constructed and calibrated for measurement of radiation absorbed dose. The system utilizes a thermistor to detect the radiation-induced temperature rise in the polystyrene absorber at certain point from the radiation source. A temperature stability of as low as 0.0018 degree C/min in a 42.0 degree C environment, and a gamma-radiation sensitivity of as high as 1.9720 ohm/Gy were obtained. Comparisons of the results obtained by using the polystyrene-water calorimeter with those obtained by applying other types of calorimeters i.e., water and graphite calorimeters were also done to aid in the possible realization of an accurate and efficient instrument for use under widely different irradiation conditions. 4 figs., 1 tab.

  8. 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

  9. Absorbed Doses and Risk Estimates of {sup 211}At-MX35 F(ab'){sub 2} in Intraperitoneal Therapy of Ovarian Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Cederkrantz, Elin [Department of Radiation Physics, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Andersson, Håkan [Department of Oncology, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Bernhardt, Peter; Bäck, Tom [Department of Radiation Physics, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Hultborn, Ragnar [Department of Oncology, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Jacobsson, Lars [Department of Radiation Physics, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Jensen, Holger [PET and Cyclotron Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital, Copenhagen (Denmark); Lindegren, Sture [Department of Radiation Physics, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Ljungberg, Michael [Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund (Sweden); Magnander, Tobias; Palm, Stig [Department of Radiation Physics, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Albertsson, Per, E-mail: per.albertsson@oncology.gu.se [Department of Oncology, Institute for Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden)

    2015-11-01

    Purpose: Ovarian cancer is