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Sample records for absorbed dose dose

  1. Absorbed Dose and Dose Equivalent Calculations for Modeling Effective Dose

    Science.gov (United States)

    Welton, Andrew; Lee, Kerry

    2010-01-01

    While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to humans is presented. However, in order to calculate effective dose, dose equivalent calculations are needed. Dose equivalent takes into account an absorbed dose of radiation and the biological effectiveness of ionizing radiation. This is important in preventing long-term, stochastic radiation effects in humans spending time in space. Monte carlo simulations run with the particle transport code FLUKA, give absorbed and equivalent dose data for relevant shielding. The shielding geometry used in the dose calculations is a layered slab design, consisting of aluminum, polyethylene, and water. Water is used to simulate the soft tissues that compose the human body. The results obtained will provide information on how the shielding performs with many thicknesses of each material in the slab. This allows them to be directly applicable to modern spacecraft shielding geometries.

  2. Absorbed radiation dose on LHC interconnects

    CERN Document Server

    Versaci, R; Vlachoudis, V; CERN. Geneva. ATS Department

    2011-01-01

    Here we present the results of our FLUKA simulations devoted to the evaluation of the peak dose absorbed by the busbar insulator in the LHC Interaction Region 7 interconnects. The peak dose absorbed by the cold magnet coils are also presented.

  3. Absorbed dose uncertainty estimation for proton therapy

    Directory of Open Access Journals (Sweden)

    Spasić-Jokić Vesna

    2012-01-01

    Full Text Available Successful radiotherapy treatment depends on the absorbed dose evaluation and the possibility to define metrological characteristics of the therapy beam. Radiotherapy requires tumor dose delivery with expanded uncertainty less than ±5 %. It is particularly important to reduce uncertainty during therapy beam calibration as well as to apply all necessary ionization chamber correction factors. Absorbed dose to water was determined using ionometric method. Calibration was performed in reference cobalt beam. Combined standard uncertainty of the calculated absorbed dose to water in 65 MeV proton beam was ±1.97% while the obtained expanded uncertainty of absorbed dose for the same beam quality was ±5.02%. The uncertainty estimation method has been developed within the project TESLA.

  4. Organ absorbed doses in intraoral dental radiography.

    Science.gov (United States)

    Lecomber, A R; Faulkner, K

    1993-11-01

    A dental radiography unit operating at 70 kV (nominal) and 20 cm focus-skin distance was used to irradiate an anthropomorphic phantom loaded with lithium fluoride thermoluminescent dosemeters, in order to assess the variation in organ absorbed dose with intraoral periapical radiographic view. 14 views using the bisecting-angle technique and four views using the paralleling technique were studied. The results are presented and the doses and dose distributions examined. Doses for the paralleling and bisecting-angle techniques are compared, and the effects of focus-skin distance and beam collimation upon patient dosimetry discussed. Sources of uncertainty in dental dosimetry studies using phantoms are also considered.

  5. 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.

  6. Absorbed dose determination in water. I

    International Nuclear Information System (INIS)

    Novotny, J.

    1991-01-01

    The use of new values of physical parameters as recommended by international organizations has consequences in radiotherapy, e.g. in the determination of absorbed doses in water based on ionometric measurements. A procedure is proposed for the determination of the conversion factor K w,u between kerma in air and absorbed dose in water, and of the factor C w,u between exposure measured and absorbed dose in water, for ionization chambers and high-energy photon beams. The conversion factors depend not only on the radiation quality but also on the dimensions and composition of the chamber and of the cup used in the calibrations. Numerical values are given for conventional kinds of ionization chambers. (author). 3 tabs., 16 refs

  7. Absorbed dose determination in water. II

    International Nuclear Information System (INIS)

    Novotny, J.; Hobzova, L.; Kindlova, A.

    1991-01-01

    The use of new values of physical parameters as recommended by international organizations has consequences in radiotherapy, e.g. in the determination of absorbed doses in water based on ionometric measurements. A procedure is proposed for the determination of the conversion factor K w,e from kerma in air to absorbed dose in water, and of the conversion factor C w,e from exposure measured to dose absorbed in water, this for ionization chambers and high-energy electron beams. The conversion factors depend not only on the radiation quality and measurement depth in the phantom but also on the dimensions and composition of the chamber and of the cup used in the calibrations. Numerical values are given for two conventional kinds of ionization chambers. (author). 3 tabs., 9 refs

  8. 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

  9. Absorbed Doses to Patients in Nuclear Medicine

    International Nuclear Information System (INIS)

    Leide-Svegborn, Sigrid; Mattsson, Soeren; Nosslin, Bertil; Johansson, Lennart

    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: 11 C- acetate, 11 C- methionine, 18 F-DOPA, whole antibody labelled with either 99m Tc, 111 In, 123 I or 131 I, fragment of antibody, F(ab') 2 labelled with either 99m Tc, 111 In, 123 I or 131 I and fragment of antibody, Fab' labelled with either 99m Tc, 111 In, 123 I or 131 I. The absorbed dose estimates for these substances have been made from published biokinetic information. For other substances of interest, e.g. 14 C-urea (children age 3-6 years), 14 C-glycocholic acid, 14 C-xylose and 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

  10. 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)

  11. 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)

  12. Fetal absorbed doses by radiopharmaceutical administration

    International Nuclear Information System (INIS)

    Rojo, Ana M; Gomez Parada, Ines M.; Di Trano, Jose L.

    2000-01-01

    The radiopharmaceutical administration with diagnostic or therapeutic purpose during pregnancy implies a prenatal radiation dose. The dose assessment and the evaluation of the radiological risks become relevant due to the great radiosensitivity of the fetal tissues in development. This paper is a revision of the available data for estimating fetal doses in the cases of the more frequently used radiopharmaceuticals in nuclear medicine, taking into account recent investigation in placental crossover. The more frequent diagnostic and therapeutic procedures were analyzed according to the radiation doses implied. (author)

  13. 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

  14. 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

  15. Application of a new style silicon absorbed dose calorimeter

    International Nuclear Information System (INIS)

    An Jinxia; Ba Weizhen; Wu Qinzhi; He Chengfa; Chen Zhaoyang

    2000-01-01

    The structure and electrical calibration and measurement principle of a new style silicon absorbed dose calorimeter are described. The distribution of dose rate with the distance in a 60 Co radiation room is given, and the dose during lifting-falling 60 Co radiation is also measured. Its results show that dose during lifting-falling 60 Co radiation can not be ignored, especially the radiation for the short time, for short distance or for little dose

  16. Radiation sensitive medium for recording an absorbed dose distribution

    DEFF Research Database (Denmark)

    2017-01-01

    The invention relates to a radiation sensitive medium for recording an absorbed dose distribution from an external radiation source such as e.g. a linear particle accelerator used for e.g. cancer treatment or radiation processing. The invention further relates to a method for measuring the absorbed...... doses distribution in a radiation sensitive medium....

  17. Effect of Bilirubin concentration on radiation absorbed dose ...

    African Journals Online (AJOL)

    Results indicate that at low concentrations (25 mol/L to 76 mol/L) absorbed doses decreased with increase in bilirubin concentration. At higher bilirubin concentrations (76 mol/L to 460 mol/L) and beyond, there was an increase in absorption with a strong positive correlation (r = 0.92) between dose absorbed and ...

  18. Absorbed doses to patients from angioradiology

    International Nuclear Information System (INIS)

    Rodriguez-Romero, R.; Hernandez-Armas, J.; Diaz-Romero, F.

    2001-01-01

    The aim of study was to know patients doses exposes when three different procedures of angioradiology were carried out. The explorations considered were drainage biliary, varicocele embolization and dacriocistography made in the Radiodiagnostic Service at the University Hospital of Canary Islands, Tenerife (Spain). In total 14 patients were studied. The measurements were made using large area transmission ionisation chamber which gives the values of Dose Area Product (DAP). In addition, thermoluminescent dosimeters type TLD-100 were used in anthropomorphic phantom in order to obtain values of organ doses when the phantom was submitted to the same procedures rather than the actual patients. Furthermore, the Effdose program was used to estimate the effective doses in the procedures conditions. The values for DAP were in the range of 70-300 for drainage biliary, 43-180 for varicocele embolization and 1.4-9 for dacriocistography. The organ doses measured with TLD-100 were higher than the corresponding values estimated by Effdose program. The results for varicocele embolization were higher than other published data. In the case of drainage biliary procedure, the values were closed to other published results. It was not possible to find data for dacriocistography from other authors. (author)

  19. Depth absorbed dose distributions for electrons

    International Nuclear Information System (INIS)

    Fregene, A.O.

    1980-01-01

    There is controversy over the comparative depth dose distributions produced by 10 MeV microtron and linear accelerator electron beams. The arguments produced by Brahme and Svensson in their rejection of silicon diode and LiF depth dose measurements (1976, Phys. Med. Biol., vol. 21, 304; 1978, Phys. Med. Biol., vol. 23, 788) have been shown to be insubstantial. These depth dose measurements in fact confirm that the two types of electron beam are not significantly different at 10 MeV. The significant differences originally reported by Brahme et al. on the basis of liquid ionisation chamber measurements (Brahme, A., Hulten, G., and Svensson, H., 1975, Phys. Med. Biol., vol. 20, 39), and the implied clinical advantage of the microtron, therefore both remain in doubt. (UK)

  20. 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)

  1. 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)

  2. 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)

  3. 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

  4. Comparison of absorbed doses resulting from various intraoral periapical radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Mi Ae; Park, Tae Won [Dept. of Oral and Maxillofacial Radiology, Graduate School, Seoul National University, Seoul (Korea, Republic of)

    1995-08-15

    This study was designed to measure the absorbed dose to organs of special interest from full mouth with intraoral film (14 films) and to compare the five periapical techniques. Thermoluminescent crystals (TLD-100 chip) were located in brain, orbit, bone marrow of mandibular ramus, bone marrow of mandibular body, bone marrow of 4th cervical spine, parotid gland, submandibular gland and thyroid gland. X-ray machine was operated at 70 kVp and round collimating film holding device (XCP) and rectangular collimating film holding device (Precision Instrument) were used. The distance from the X-ray focus to the open end of the collimator was 8 inch, 12 inch and 16 inch. The following results obtained; 1. The absorbed dose was the highest in bone marrow of mandibular body (5.656 mGy) and the lowest in brain (0.050 mGy). 2. Generally, the lowest absorbed dose was measured from 16 inch cylinder, rectangular collimating film holding device with paralleling technique. But, in bone marrow of mandibular body and the floor of mouth, the highest absorbed dose was measured from 12 inch cylinder, rectangular collimating film holding device with paralleling techniques. 3. Comparing of five intraoral radiographic techniques, it was appeared statistically significant reduction of the absorbed doses measured with rectangualr collimating film holding device compared to XCP film holding device (p<0.05). 4. No statistically significant reduction in the absorbed dose was found as cylinder length was change (p>0.05).

  5. 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

  6. Comparison of absorbed doses resulting from various intraoral periapical radiography

    International Nuclear Information System (INIS)

    Kang, Mi Ae; Park, Tae Won

    1995-01-01

    This study was designed to measure the absorbed dose to organs of special interest from full mouth with intraoral film (14 films) and to compare the five periapical techniques. Thermoluminescent crystals (TLD-100 chip) were located in brain, orbit, bone marrow of mandibular ramus, bone marrow of mandibular body, bone marrow of 4th cervical spine, parotid gland, submandibular gland and thyroid gland. X-ray machine was operated at 70 kVp and round collimating film holding device (XCP) and rectangular collimating film holding device (Precision Instrument) were used. The distance from the X-ray focus to the open end of the collimator was 8 inch, 12 inch and 16 inch. The following results obtained; 1. The absorbed dose was the highest in bone marrow of mandibular body (5.656 mGy) and the lowest in brain (0.050 mGy). 2. Generally, the lowest absorbed dose was measured from 16 inch cylinder, rectangular collimating film holding device with paralleling technique. But, in bone marrow of mandibular body and the floor of mouth, the highest absorbed dose was measured from 12 inch cylinder, rectangular collimating film holding device with paralleling techniques. 3. Comparing of five intraoral radiographic techniques, it was appeared statistically significant reduction of the absorbed doses measured with rectangualr collimating film holding device compared to XCP film holding device (p 0.05).

  7. Space radiation absorbed dose distribution in a human phantom

    Science.gov (United States)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  8. 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

  9. Radiographic fallopian tube recanalization: Absorbed ovarian radiation dose

    International Nuclear Information System (INIS)

    Hedgpeth, P.L.; Thurmond, A.S.; Fry, R.; Schmidgall, J.R.; Roesch, J.

    1991-01-01

    Absorbed radiation dose to the ovaries during radiographic fallopian tube recanalization was estimated in 29 patients with use of thermoluminescent dosimeters placed in the vaginal fornix. With an average fluoroscopic time of 8.5 minutes ± 5.5 and an average of 14 ± 5 105-mm spot radiographs obtained, the average absorbed dose to the ovaries was 8.5 mGy ± 5.6 (0.85 rad ± 0.56). Technical guidelines for keeping patient radiation exposure to a minimum during this new interventional procedure are suggested

  10. Radiographic fallopian tube recanalization: Absorbed ovarian radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Hedgpeth, P.L.; Thurmond, A.S.; Fry, R.; Schmidgall, J.R.; Roesch, J. (Department of Diagnostic Radiology, Oregon Health Sciences University, Portland (USA))

    1991-07-01

    Absorbed radiation dose to the ovaries during radiographic fallopian tube recanalization was estimated in 29 patients with use of thermoluminescent dosimeters placed in the vaginal fornix. With an average fluoroscopic time of 8.5 minutes {plus minus} 5.5 and an average of 14 {plus minus} 5 105-mm spot radiographs obtained, the average absorbed dose to the ovaries was 8.5 mGy {plus minus} 5.6 (0.85 rad {plus minus} 0.56). Technical guidelines for keeping patient radiation exposure to a minimum during this new interventional procedure are suggested.

  11. The absorbed dose and the effective dose of panoramic temporo mandibular joint radiography

    International Nuclear Information System (INIS)

    Matsuo, Ayae; Gotoh, Kenichi; Yokoi, Midori; Hirukawa, Akiko; Okumura, Shinji; Okano, Tsuneichi; Koyama, Syuji

    2011-01-01

    This study measured the radiation doses absorbed by the patient during Panoramic temporo mandibular joint radiography (Panoramic TMJ), Schullers method and Orbitoramus projection. The dose of the frontal view in Panoramic TMJ was compared to that with Orbitoramus projection and the lateral view in Panoramic TMJ was compared to that with Schuellers method. We measured the doses received by various organs and calculated the effective doses using the guidelines of the International Commission on Radiological Protection in Publication 103. Organ absorbed doses were measured using an anthropomorphic phantom, loaded with thermoluminescent dosimeters (TLD), located at 160 sensitive sites. The dose shows the sum value of irradiation on both the right and left sides. In addition, we set a few different exposure field sizes. The effective dose for a frontal view in Panoramic TMJ was 11 μSv, and that for the lateral view was 14 μSv. The lens of the Orbitoramus projection was 40 times higher than the frontal view in Panoramic TMJ. Although the effective dose of the lateral view in Panoramic TMJ was 3 times higher than that of the small exposure field (10 x 10 cm on film) in Schueller's method, it was the same as that of a mid-sized exposure field. When the exposure field in the inferior 1/3 was reduced during panoramic TMJ, the effective doses could be decreased. Therefore we recommend that the size of the exposure field in Panoramic TMJ be decreased. (author)

  12. 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

  13. 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.

  14. 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)

  15. 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...

  16. 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)

  17. 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.

  18. 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

  19. 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.

  20. 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 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......Thin radiochromic dye films are useful for measuring large radiation absorbed doses (105–108 rads) and for high-resolution imaging of dose patterns produced by penetrating radiation beams passing through non-homogeneous media. Certain types of amino-substituted triarylmethane cyanides dissolved...... in polymeric solutions can be cast into flexible free-standing thin films of uniform thickness and reproducible response to ultraviolet and ionizing radiation. The increase in optical density versus energy deposited by radiation is linear over a wide range of doses and is for practical purposes independent...

  1. 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)

  2. 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)

  3. 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)

  4. 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)

  5. 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)

  6. 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

  7. Absorbed dose rate produced by patients with I-131

    International Nuclear Information System (INIS)

    Gonzalez-Vila, V.; Luis-Simon, J.; Gomez-Puerto, A.; Rodriguez, J.R.

    1992-01-01

    This paper shows the values of absorbed dose rates per unit of activity produced by patients treated with Iodine 131 due to Thyroid cancer. Average values related to disease extension, age and sex are established according to out current schedule of Radiological Protection Measures. From this data we have obtained a more accurate calculation for the value used in clinical emergency : 1471 nGy/>MBq over the relevant tissue. 40 treatment performed during 14 months are studied and comments are made on the Iodine retention by thyroideal tissue related to patient's clinical conditions as well size and site of thyroideal tissue and/or TSH simulation. (author)

  8. 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

  9. Determination of Absorbed Dose in Large 60-Co Fields Radiotherapy

    International Nuclear Information System (INIS)

    Hrsak, H.

    2003-01-01

    Radiation in radiotherapy has selective impact on ill and healthy tissue. During the therapy the healthy tissue receives certain amount of dose. Therefore dose calculations in outer radiotherapy must be accurate because too high doses produce damage in healthy tissue and too low doses cannot ensure efficient treatment of cancer cells. A requirement on accuracy in the dose calculations has lead to improvement of detectors, and development of absolute and relative dosimetry. Determination of the dose distribution with use of computer is based on data provided by the relative dosimetry. This paper compares the percentage depth doses in cubic water phantoms of various dimensions with percentage depth doses calculated with use of Mayneord factor from the experimental depth doses measured in water phantom of large dimension. Depth doses in water phantoms were calculated by the model of empirical dosimetrical functions. The calculations were based on the assumption that large 6 0C o photon field exceeds the phantom's limits. The experimental basis for dose calculations by the model of empirical dosimetrical functions were exposure doses measured in air and dose reduction factors because of finite phantom dimensions. Calculations were performed by fortran 90 software. It was found that the deviation of dosimetric model was small in comparison to the experimental data. (author)

  10. 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...

  11. 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

  12. Calibration of film dosimeters by means of absorbed dose calorimeters

    International Nuclear Information System (INIS)

    Nikolaev, S.M.; Vanyushkin, B.M.; Kon'kov, N.G.

    1980-01-01

    Methods of graduating film dosimeters by means of calorimeters of absorbed doses, are considered. Graduating of film dosimeters at the energies of accelerated electrons from 4 to 10 MeV can be carried out by means of quasiadiabatic calorimeter of local absorption, the absorber thickness of which should not exceed 5-10% of Rsub(e) value, where Rsub(e) - free electron path of the given energy. In this case film is located inside the calorimeter. For graduating films with thickness not less than (0.1-0.2)Rsub(e) it is suggested to use calorimeter of full absorption; then the graduated dosimeters are located in front of the calorimeter. Graduation of films at small energies of electrons is exercised by means of a package of films, approximately Rsub(e) thick. A design of quasiadiabatic calorimeter, intended for graduating dosimeters within the energy range of electron beam from 4 to 10 MeV, is considered. The quasiadiabatic calorimeter is a thin graphite tablet with heater and thermocouple, surrounded by foam plastic thermostating case. Electricity quantity, accumulated during the radiation field pass, is measured in the case of using the quasiadiabatic calorimeter for film graduating. The results of graduating film dosimeters, obtained using film package with Rsub(e) thickness, are presented. The obtained results coincide within 5% limits with the data known beforehand [ru

  13. 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)

  14. 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)

  15. 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

  16. Absorbed dose evaluations in retrospective dosimetry: Methodological developments using quartz

    DEFF Research Database (Denmark)

    Bailiff, I.K.; Bøtter-Jensen, L.; Correcher, V.

    2000-01-01

    -300 mGy were obtained using TL (210 degreesC TL and pre-dose) and OSL (single and multiple aliquot) procedures. Overall, good inter-laboratory concordance of dose evaluations was achieved, with a variance (1 sigma) of similar to+/-10 mGy for the samples examined. (C) 2000 Elsevier Science Ltd. All...

  17. Referent 3D solid tumour model and absorbed dose calculations at cellular level in radionuclide therapy

    International Nuclear Information System (INIS)

    Spaic, R.; Ilic, R.; Petrovic, B.; Dragovic, M.; Toskovic, F.

    2007-01-01

    An average absorbed dose of the tumour calculated by the MIRD formalism has not always a good correlation with the clinical response. The basic assumption of the MIRD schema is that a uniform spatial dose distribution is opposite to heterogeneity of intratumoral distribution of the administered radionuclide which can lead to a spatial nonuniformity of the absorbed dose. Therefore, in clinical practice, an absorbed dose of the tumour at the cellular level has to be calculated. The aim of this study is to define a referent 3D solid tumour model and using the direct Monte Carlo radiation transport method to calculate: a) absorbed fraction, b) spatial 3D absorbed dose distribution, c) absorbed dose and relative absorbed dose of cells or clusters of cells, and d) differential and accumulated dose volume histograms. A referent 3D solid tumour model is defined as a sphere which is randomly filled with cells and necrosis with defined radii and volumetric density. Radiolabelling of the tumour is defined by intracellular to extracellular radionuclide concentration and radio-labelled cell density. All these parameters are input data for software which generates a referent 3D solid tumour model. The modified FOTELP Monte Carlo code was used on this model for simulation study with beta emitters which were applied on the tumour. The absorbed fractions of Cu-67, I- 131, Re-188 and Y-90 were calculated for different tumour sphere masses and radii. Absorbed doses of cells and spatial distributions of the absorbed doses in the referent 3D solid tumour were calculated for radionuclides I-131 and Y-90. Dose scintigram or voxel presentation of absorbed dose distributions showed higher homogeneity for Y-90 than for I-131. A differential dose volume histogram, or spectrum, of the relative absorbed dose of cells, was much closer to the average absorbed dose of the tumour for Y-90 than I-131. An accumulated dose volume histogram showed that most tumour cells received a lower dose than

  18. Control of absorbed dose in radiotherapy with 60 Co units

    International Nuclear Information System (INIS)

    Penchev, V.; Constantinov, B.; Buchakliev, Z.

    2000-01-01

    A Network for External Quality Audit has been developed and established in Bulgaria by the Secondary Standard Dosimetry Laboratory (SSDL) - Sofia. The results prove the usefulness of the TL Postal Dose programme in helping Bulgarian radiotherapy departments improve and maintain the consistency of patient doses in clinically acceptable level. The participation of the SSDL-Sofia in the IAEA Quality Audit Programme confirms the quite satisfactory accuracy of the therapy level dose measurements and determination achieved. The role of the SSDL is critical in providing traceable calibration to hospitals

  19. Biological indicators for radiation absorbed dose: a review

    International Nuclear Information System (INIS)

    Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

    1996-01-01

    Biological dosimetry has an important role to play in assessing the cumulative radiation exposure of persons working with radiation and also in estimating the true dose received during accidents involving external and internal exposure. Various biodosimetric methods have been tried to estimate radiation dose for the above purposes. Biodosimetric methods include cytogenetic, immunological and mutational assays. Each technique has certain advantages and disadvantages. We present here a review of each technique, the actual method used for detection of dose, the sensitivity of detection and its use in long term studies. (author)

  20. Absorbed and effective dose in direct and indirect digital panoramic radiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gun Sun; Kim, Jin Soo; Kim, Jae Duk [Department of Oral and Maxilloficial Radiology School of Dentistry, Oral Biology Research Institute, Chosun University, Gwangju (Korea, Republic of)

    2010-03-15

    We evaluated the absorbed doses to the organs and calculated the effective doses when using the digital panoramic radiography. The absorbed dose averages in major organs of oral and maxillofacial region were measured using the Dental head phantom (CIRS Co., USA), nLi2B4O7 TLD chip and UD-716AGL dosimeter (Matsushita Electric Industrial Co., JPN) when performing indirect and direct digital panoramic radiography. Effective doses were calculated from correspond to ICRP 2007 recommendations for two panoramic radiography. The absorbed dose average on indirect and direct digital panoramic radiography was highest in parotid glands as measured 1259.6 mGy and 680.7 mGy respectively. Absorbed dose average in another organs were high in order of esophagus, submandibular gland, tongue and thyroid gland on both types of digital panoramic radiography. The absorbed dose average was higher on indirect type than direct one (p?0.05). The effective dose was higher on indirect type than direct one as measured 13.28 mSv and 8.70 mSv respectively. The absorbed doses in salivary gland and oral mucosa were high. However, thyroid gland also demands the attention on radiography due to high tissue weighting factor in spite of the low absorbed dose.

  1. Absorbed and effective dose in direct and indirect digital panoramic radiography

    International Nuclear Information System (INIS)

    Lee, Gun Sun; Kim, Jin Soo; Kim, Jae Duk

    2010-01-01

    We evaluated the absorbed doses to the organs and calculated the effective doses when using the digital panoramic radiography. The absorbed dose averages in major organs of oral and maxillofacial region were measured using the Dental head phantom (CIRS Co., USA), nLi2B4O7 TLD chip and UD-716AGL dosimeter (Matsushita Electric Industrial Co., JPN) when performing indirect and direct digital panoramic radiography. Effective doses were calculated from correspond to ICRP 2007 recommendations for two panoramic radiography. The absorbed dose average on indirect and direct digital panoramic radiography was highest in parotid glands as measured 1259.6 mGy and 680.7 mGy respectively. Absorbed dose average in another organs were high in order of esophagus, submandibular gland, tongue and thyroid gland on both types of digital panoramic radiography. The absorbed dose average was higher on indirect type than direct one (p?0.05). The effective dose was higher on indirect type than direct one as measured 13.28 mSv and 8.70 mSv respectively. The absorbed doses in salivary gland and oral mucosa were high. However, thyroid gland also demands the attention on radiography due to high tissue weighting factor in spite of the low absorbed dose.

  2. 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.

  3. 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

  4. 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

  5. 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

  6. Status of air kerma and absorbed dose standards in India

    International Nuclear Information System (INIS)

    Vijayam, M.; Ramanathan, G.; Patki, V.S.; Soman, A.T.; Shigwan, J.B.; Vinatha, S.P.; Jadhavgaonkar, P.S.; Kadam, V.D.; Shaha, V.V.; Abani, M.C.

    2002-01-01

    -rays, chambers of the type Exradin A2, NE 2571, NE2577, Victoreen 415 B, Victoreen 415, Exradin A3 and NE 2581 are maintained. These chambers have been calibrated against the primary standards and have been used in the international intercomparison experiments. The future programme of development of standards include i) Development of graphite/water calorimeters as absorbed dose standards, ii) Establishment of extrapolation chamber as primary standard for absorbed dose for beta and soft x-ray beams and iii) Development of energy-independent plastic scintillators as reference standard for low energy low activity brachytherapy sources. (author)

  7. Dose absorbed in the fetus by radioactive drugs prescribed

    International Nuclear Information System (INIS)

    Rojo, A.M.; Gomez Parada, I.; Di Trano, J.L.

    1998-01-01

    This work aims to review existing guidelines on the hypothesis that must be taken into account when calculating impact from the dose on the fetus for widely employed radioactive drugs. Recent research is added giving data on placenta transference linked to pregnancy term. The most widely used diagnostic and therapeutic practices are analyzed comparing the dose impact on the fetus with limits internationally accepted. This will allow having the necessary tools to answer questions concerning radiological risks due to the administration of radioactive drugs to pregnant women

  8. Absorbed dose in polymers during a positron annihilation experiment

    International Nuclear Information System (INIS)

    Suzuki, T.; Namito, Y.; Oki, Y.; Numajiri, M.; Miura, T.; Hirayama, H.; Kondo, K.; Ito, Y.

    1994-01-01

    A positron annihilation lifetime (PAL) technique has been recognized as being a useful method to study the characteristics of polymers. However, radiation effects due to positrons used as a probe have been raised as being a problem, since positrons emitted from 22 Na have sufficient energy to induce radiation damage in polymers. In this study, the radiation dose induced by positrons emitted from 22 Na was estimated for such polymers like polyethylenes and polypropylenes using the EGS4 code. The radiation damage during PAL measurements is also discussed. It has been shown that the calculated dose is consistent with that estimated from an empirical equation of the mass-attenuation coefficient. (author)

  9. 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.

  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. Plastic film materials for dosimetry of very large absorbed doses

    DEFF Research Database (Denmark)

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

    1985-01-01

    Most plastic films have limited response ranges for dosimetry because of radiation-induced brittleness, degradation, or saturation of the signal used for analysis (e.g. spectrophotometry) at high doses. There are, however, a few types of thin plastic films showing linearity of response even up...

  12. Studies of absorbed dose determinations and spatial dose distributions for high energy proton beams

    International Nuclear Information System (INIS)

    Hiraoka, Takeshi

    1982-01-01

    Absolute dose determinations were made with three types of ionization chamber and a Faraday cup. Methane based tissue equivalent (TE) gas, nitrogen, carbon dioxide, air were used as an ionizing gas with flow rate of 10 ml per minute. Measurements were made at the entrance position of unmodulated beams and for a beam of a spread out Bragg peak at a depth of 17.3 mm in water. For both positions, the mean value of dose determined by the ionization chambers was 0.993 +- 0.014 cGy for which the value of TE gas was taken as unity. The agreement between the doses estimated by the ionization chambers and the Faraday cup was within 5%. Total uncertainty estimated in the ionization chamber and the Faraday cup determinations is 6 and 4%, respectively. Common sources of error in calculating the dose from ionization chamber measurements are depend on the factors of ion recombination, W value, and mass stopping power ratio. These factors were studied by both experimentally and theoretically. The observed values for the factors show a good agreement to the predicted one. Proton beam dosimetry intercomparison between Japan and the United States was held. Good agreement was obtained with standard deviation of 1.6%. The value of the TE calorimeter is close to the mean value of all. In the proton spot scanning system, lateral dose distributions at any depth for one spot beam can be simulated by the Gaussian distribution. From the Gaussian distributions and the central axis depth doses for one spot beam, it is easy to calculate isodose distributions in the desired field by superposition of dose distribution for one spot beam. Calculated and observed isodose curves were agreed within 1 mm at any dose levels. (J.P.N.)

  13. Plastic film materials for dosimetry of very large absorbed doses

    DEFF Research Database (Denmark)

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

    1985-01-01

    , polystyrene, dyed and undyed polyhalostyrenes, dyed aromatic polyamides, and polyvinylidene fluoride. Although most of these systems have fairly stable absorption spectra after irradiation, tests of dependence on dose rate and on temperature during irradiation show that only polystyrene and some...... of the polyhalostyrenes have essentially rate-independent and moderately temperature-dependent responses to such large doses of ionizing radiation. While radiation-induced optical absorption in the ultraviolet for polystyrene is unstable following irradiation, thus leading to an intrinsic low-intensity rate dependence......, the dyed polychlorostyrenes show essentially the same response to radiation-processing gamma-ray fields and to very high-intensity electron beams, and a relatively stable absorption spectrum at wavelengths for dosimetry analysis in the visible spectral region of ≈430 nm....

  14. Radiation absorbed dose to the human fetal thyroid

    International Nuclear Information System (INIS)

    Watson, E.E.

    1992-01-01

    The embryo/fetus is recognized to be particularly susceptible to damage from exposure to radiation. Many advisory groups have studied available information concerning radiation doses and radiation effects with the goal of reducing the risk to the embryo/fetus. Of particular interest are radioactive isotopes of iodine. Radioiodine taken into the body of a pregnant woman presents a possible hazard for the embryo/fetus. The fetal thyroid begins to concentrate iodine at about 13 weeks after conception and continues to do so throughout gestation. At term, the organic iodine concentration in the fetal blood is about 75% of that in the mother's blood. This paper presents a review the models that have been proposed for the calculation of the dose to the fetal thyroid from radioisotopes of iodine taken into the body of the pregnant woman as sodium iodide. A somewhat different model has been proposed, and estimates of the radiation dose to the fetal thyroid calculated from this model are given for each month of pregnancy from 123 I , 124 I , 125 I , and 131 I

  15. Patient absorbed dose and radiation risk in nuclear medicine

    International Nuclear Information System (INIS)

    Hetherington, E.; Cochrane, P.

    1992-01-01

    Since the introduction of technetium-99m labelled radiopharmaceuticals used as imaging agents in the nuclear medicine departments of Australian hospitals, patients have voiced concern about the effect of having radioactive materials injected into their bodies. The danger of X-ray exposure is widely known and well accepted, as is exposure to ultrasound, computed tomography scans and other imaging techniques. However, radioactivity is an unknown, and fear of the unknown can occasionally lead to patients refusing to undergo a nuclear medicine procedure. The authors emphasised that the radiation dose to a patient from a typical procedure would depend on the patient's medical history and treatment; the average dose being approximately 50 times the exposure received from the natural environmental background radiation. Furthermore, over an extended period the body can repair most minor damage caused by radiation, just as the body can repair the damage caused by sunburn resulting from too much exposure to sunlight. The risk of genetic effects as a result of a medical radiation dose is than very small

  16. 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)

  17. Measuring absorbed dose for i-CAT CBCT examinations in child, adolescent and adult phantoms.

    Science.gov (United States)

    Choi, E; Ford, N L

    2015-01-01

    Design and construct child and adolescent head phantoms to measure the absorbed doses imparted during dental CBCT and compare with the absorbed dose measured in an adult phantom. A child phantom was developed to represent the smallest patients receiving CBCT, usually for craniofacial developmental concerns, and an adolescent phantom was developed to represent healthy orthodontic patients. Absorbed doses were measured using a thimble ionization chamber for the custom-built child and adolescent phantoms and compared with measurements using a commercially available adult phantom. Imaging was performed with an i-CAT Next Generation (Imaging Sciences International, Hatfield, PA) CBCT using two different fields of view covering the craniofacial complex (130 mm high) or maxilla/mandible (60 mm high). Measured absorbed doses varied depending on the location of the ionization chamber within the phantoms. For CBCT images obtained using the same protocol for all phantoms, the highest absorbed dose was measured in all locations of the small child phantom. The lowest absorbed dose was measured in the adult phantom. Images were obtained with the same protocol for the adult, adolescent and child phantoms. A consistent trend was observed with the highest absorbed dose being measured in the smallest phantom (child), while the lowest absorbed dose was measured in the largest phantom (adult). This study demonstrates the importance of child-sizing the dose by using dedicated paediatric protocols optimized for the imaging task, which is critical as children are more sensitive to harmful effects of radiation and have a longer life-span post-irradiation for radiation-induced symptoms to develop than do adults.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jeong Yeon; Han, Won Jeong; Kim, Eun Kyung [Dankook Univ. School of Dentistry, Seoul (Korea, Republic of)

    2007-09-15

    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.

  19. 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

  20. Absorbed dose measurements of insulating material for TRISTAN magnets by IR spectrometry

    International Nuclear Information System (INIS)

    Endo, Kuninori; Ohsawa, Yasunobu; Michikawa, Taichi.

    1995-01-01

    Absorbed dose measurements of the insulating material for 29GeV TRISTAN Main-Ring magnets were carried out with the Infrared spectrometry. From the fact that carbonyl radical is induced in epoxy resin by irradiation, infrared absorbance in the range of 1705-1720 cm -1 due to carbonyl radicals was applied to the estimations of the absorbed dose of the epoxy resin. Relationship between absorbance of carbonyl band and absorbed dose was investigated exposing the epoxy resin in two irradiation fields, TRISTAN MR and irradiation facility of 3kCi 60 Co source. From this work, it was found that IR absorbance method could be applied to the absorbed dose measurements from 10 3 to 10 7 Gy and that absorbed doses obtained from 31 specimens of epoxy resin shaved from coils of TRISTAN MR magnets had a distribution extending from 2.6 x 10 3 to 1.07 x 10 7 Gy, mostly order of 10 4 to 10 5 Gy. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Leide-Svegborn, Sigrid; Mattsson, Soeren; Johansson, Lennart; Fernlund, Per; Nosslin, Bertil

    2007-04-15

    The Swedish radiation protection authority, (SSI), has supported work on estimates of radiation doses to patients from nuclear medicine examinations since more than 20 years. A number of projects have been reported. The results are put together and published under the name 'Doskatalogen' which contains data on doses to different organs and tissues from radiopharmaceuticals used for diagnostics and research. This new report contains data on: {sup 11}C-labelled substances (realistic maximum model), amino acids labelled with {sup 11}C, {sup 18}F or {sup 75}Se, {sup 99m}Tc-apcitide, {sup 123}I-labelled fatty acids ({sup 123}I- BMIPP and {sup 123}I-IPPA) and revised models for previously reported {sup 15}O-labelled water, {sup 99m}Tc-tetrofosmin (rest as well as exercise) and {sup 201}Tl-ion Data for almost 200 substances and radionuclides are included in the 'Doskatalogen' today. Since the year 2001 the 'Doskatalogen' is available on the authority's home page (www.ssi.se)

  2. 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.)

  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. 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

  5. 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

  6. 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.

  7. 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)

  8. 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)

  9. 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

  10. Absorbed dose distribution analyses in irradiation with adjacent fields

    International Nuclear Information System (INIS)

    Cudalbu, C.; Onuc, C.; Andrada, S.

    2002-01-01

    Because the special irradiation technique with adjacent fields is the most used in the case of medulloblastoma treatment, we consider very important to specify some general information about medulloblastoma. This malignant disease has a large incidence in children with age between 5-7 years. This tumor usually originates in the cerebellum and is referred to as primitive undifferentiated tumor. It may spread contiguously to the cerebellar peduncle, floor of the fourth ventricle, into the cervical spine. In addition, it may spread via the cerebrospinal fluid intracranially and/or to the spinal cord. For this purpose it is necessary to perform a treatment technique with cranial tangential fields combined with adjacent fields for the entire spinal cord to achieve a perfect coverage of the zones with malignant cells. The treatment in this case is an association between surgery-radio-chemotherapy, where the radiotherapy has a very important roll and a curative purpose. This is due to the fact that the migration of malignant cells in the body can't be controlled by surgery. Because of this special irradiation technique used in medulloblastoma treatment, we chase to describe in this paper this complex type of irradiation where the implications of the beams divergence in doses distribution are essentials

  11. Absorbed dose rate in air in metropolitan Tokyo before the Fukushima Daiichi Nuclear Power Plant accident.

    Science.gov (United States)

    Inoue, K; Hosoda, M; Fukushi, M; Furukawa, M; Tokonami, S

    2015-11-01

    The monitoring of absorbed dose rate in air has been carried out continually at various locations in metropolitan Tokyo after the accident of the Fukushima Daiichi Nuclear Power Plant. While the data obtained before the accident are needed to more accurately assess the effects of radionuclide contamination from the accident, detailed data for metropolitan Tokyo obtained before the accident have not been reported. A car-borne survey of the absorbed dose rate in air in metropolitan Tokyo was carried out during August to September 2003. The average absorbed dose rate in air in metropolitan Tokyo was 49±6 nGy h(-1). The absorbed dose rate in air in western Tokyo was higher compared with that in central Tokyo. Here, if the absorbed dose rate indoors in Tokyo is equivalent to that outdoors, the annual effective dose would be calculated as 0.32 mSv y(-1). © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. Comparison of the Absorbed Dose of Target Organs between Conventional and Digital Panoramic Radiography

    Directory of Open Access Journals (Sweden)

    Zohre Reyhani

    2016-09-01

    Full Text Available The purpose of this study was to measure and compare target organ’s exposure by direct digital and conventional panoramic radiography. Dose measurements were carried out on a RANDO phantom, which TLDs were placed into 5 target area: thyroid gland, left and right submandibular and parotid salivary glands. Panoramic radiographs were taken with two conventional (CRANEX Tome, Soredex, Tusula Finland and direct digital devices (CRANEX D, Soredex, Tusula Finland.In total, the phantom was irradiated 30 times in the two systems. The TLDs were then coded and analyzed. T-test of statistical analysis was used to find the correlation. We found statistically significant reduction in absorbed dose of target organs in digital panoramic radiography(P<0.01. The highest absorbed dose was for submandibular gland and the lowest was for thyroid gland. We concluded that can reduce absorbed dose in vital organs.

  17. Absorbed dose by thyroid in case of nuclear accidents; Dose absorvida pela tireoide em casos de acidentes nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Laelia; Attie, Marcia Regina Pereira [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Fisica; Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Amaral, Ademir [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2011-07-01

    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 ({sup 131}I, {sup 132}I, {sup 133}I, {sup 134}I and {sup 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)

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

    Science.gov (United States)

    Vega-Carrillo, Héctor René; Manzanares-Acuña, Eduardo; Hernández-Dávila, Víctor Martín; Arcos-Pichardo, Areli; Barquero, Raquel; Iñiguez, M. Pilar

    2006-09-01

    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.

  19. 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

  20. 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

  1. Absorbed Dose Distributions in Irradiated Plastic Tubing and Wire Insulation

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.

    1979-01-01

    Plastic tubing and wire insulation were simulated by radiochromic dye dosimeter films having electron absorbing properties similar to the materials of interest (polyethylene and PVC). A 400-keV electron accelerator was used to irradiate from 1, 2, 3 and 4 sides simulating possible industrial...

  2. Whole-body absorbed dose rate in a worker carrying a can with contaminated liquid on his back

    International Nuclear Information System (INIS)

    Le Grand, J.; Roux, Y.

    1990-01-01

    The method used is briefly described: geometrical parametrization by a set of planes and photon transport simulation by Monte Carlo techniques. The whole-body absorbed dose rate and the maximum absorbed dose rate in the phantom representing the worker are calculated for five photon initial energies. In order to illustrate the dose variation in the phantom, the absorbed dose rates are also given at the head, at the breast and at the gonads [fr

  3. 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

  4. 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

  5. Absorbed dose calculations using mesh-based human phantoms and Monte Carlo methods

    International Nuclear Information System (INIS)

    Kramer, Richard

    2010-01-01

    Full text. Health risks attributable to ionizing radiation are considered to be a function of the absorbed dose to radiosensitive organs and tissues of the human body. However, as human tissue cannot express itself in terms of absorbed dose, exposure models have to be used to determine the distribution of absorbed dose throughout the human body. An exposure model, be it physical or virtual, consists of a representation of the human body, called phantom, plus a method for transporting ionizing radiation through the phantom and measuring or calculating the absorbed dose to organ and tissues of interest. Female Adult meSH (FASH) and the Male Adult meSH (MASH) virtual phantoms have been developed at the University of Pernambuco in Recife/Brazil based on polygon mesh surfaces using open source software tools. Representing standing adults, FASH and MASH have organ and tissue masses, body height and mass adjusted to the anatomical data published by the International Commission on Radiological Protection for the reference male and female adult. For the purposes of absorbed dose calculations the phantoms have been coupled to the EGSnrc Monte Carlo code, which transports photons, electrons and positrons through arbitrary media. This presentation reports on the development of the FASH and the MASH phantoms and will show dosimetric applications for X-ray diagnosis and for prostate brachytherapy. (author)

  6. 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

  7. National absorbed dose to water references for radiotherapy medium energy X-rays by water calorimetry

    International Nuclear Information System (INIS)

    Perichon, N.

    2012-01-01

    LNE-LNHB current references for medium energy X-rays are established in terms of air kerma. Absorbed dose to water, which is the quantity of interest for radiotherapy, is obtained by transfer dosimetric techniques following a methodology described in international protocols. The aim of the thesis is to establish standards in terms of absorbed dose to water in the reference protocol conditions by water calorimetry. The basic principle of water calorimetry is to measure the absorbed dose from the rise in temperature of water under irradiation. A calorimeter was developed to perform measurements at a 2 cm depth in water according to IAEA TRS-398 protocol for medium energy x-rays. Absorbed dose rates to water measured by calorimetry were compared to the values established using protocols based on references in terms of air kerma. A difference lower than 2.1% was reported. Standard uncertainty of water calorimetry being 0.8%, the one associated to the values from protocols being around 3.0%, results are consistent considering the uncertainties. Thanks to these new standards, it will be possible to use IAEA TRS-398 protocol to determine absorbed dose to water: a significant reduction of uncertainties is obtained (divided by 3 by comparison with the application of the IAEA TRS-277 protocol). Currently, none of the counterparts' laboratories own such an instrument allowing direct determination of standards in the reference conditions recommended by the international radiotherapy protocols. (author) [fr

  8. Absorbed dose calculations using mesh-based human phantoms and Monte Carlo methods

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Richard [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2010-07-01

    Full text. Health risks attributable to ionizing radiation are considered to be a function of the absorbed dose to radiosensitive organs and tissues of the human body. However, as human tissue cannot express itself in terms of absorbed dose, exposure models have to be used to determine the distribution of absorbed dose throughout the human body. An exposure model, be it physical or virtual, consists of a representation of the human body, called phantom, plus a method for transporting ionizing radiation through the phantom and measuring or calculating the absorbed dose to organ and tissues of interest. Female Adult meSH (FASH) and the Male Adult meSH (MASH) virtual phantoms have been developed at the University of Pernambuco in Recife/Brazil based on polygon mesh surfaces using open source software tools. Representing standing adults, FASH and MASH have organ and tissue masses, body height and mass adjusted to the anatomical data published by the International Commission on Radiological Protection for the reference male and female adult. For the purposes of absorbed dose calculations the phantoms have been coupled to the EGSnrc Monte Carlo code, which transports photons, electrons and positrons through arbitrary media. This presentation reports on the development of the FASH and the MASH phantoms and will show dosimetric applications for X-ray diagnosis and for prostate brachytherapy. (author)

  9. 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)

  10. 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.

  11. 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

  12. Tyrosol and hydroxytyrosol are absorbed from moderate and sustained doses of virgin olive oil in humans.

    Science.gov (United States)

    Miró-Casas, E; Covas, M-I; Fitó, M; Farré-Albadalejo, M; Marrugat, J; de la Torre, R

    2003-01-01

    To investigate the absorption of tyrosol and hydroxytyrosol from moderate and sustained doses of virgin olive oil consumption. The study also aimed to investigate whether these phenolic compounds could be used as biomarkers of virgin olive oil intake. Ingestion of a single dose of virgin olive oil (50 ml). Thereafter, for a week, participants followed their usual diet which included 25 ml/day of the same virgin olive oil as the source of raw fat. Unitat de Recerca en Farmacologia. Institut Municipal d'Investigació Mèdica (IMIM). Seven healthy volunteers. An increase in 24 h urine of tyrosol and hydroxytyrosol, after both a single-dose ingestion (50 ml) and short-term consumption (one week, 25 ml/day) of virgin olive oil (P<0.05) was observed. Urinary recoveries for tyrosol were similar after a single dose and after sustained doses of virgin olive oil. Mean recovery values for hydroxytyrosol after sustained doses were 1.5-fold those obtained after a single 50 ml dose. Tyrosol and hydroxytyrosol are absorbed from realistic doses of virgin olive oil. With regard to the dose-effect relationship, 24 h urinary tyrosol seems to be a better biomarker of sustained and moderate doses of virgin olive oil consumption than hydroxytyrosol.

  13. 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.

  14. Contribution to the determination of a standard of absorbed dose in water for cobalt 60 photons

    International Nuclear Information System (INIS)

    Zitouni, Y.

    1986-07-01

    A new standard, expressed in terms of absorbed dose at a depth of 5g/cm 2 in a water phantom irradiated by cobalt 60 gamma photons, is determined. The procedure developed is based on a transfer method using two dosimetric techniques: Fricke dosimetry and ionometry (0.6 cm 3 NE 2571 radiotherapy ionization chamber). Their calibration is performed with the primary calibration standard of absorbed dose: the graphite calorimeter. The relative discrepancy between the values of absorbed dose in water determined by the chemical dosimeter and the ionization chamber is equal to 1%. The ionization chamber has been also calibrated near the Cobalt 60 reference beam characterized in terms of air kerma [fr

  15. Absorbed dose in the full-mouth periapical radiography, panoramic radiography, and zonography

    International Nuclear Information System (INIS)

    Choi, Soon Chul; Choi, Hang Moon

    1999-01-01

    The objective of this study was to evaluate the possibility of substitution of the zonography for the full-mouth periapical radiography in aspect of radiation protection. Rando phantom and LiF TLD chips were used for dosimetry. The absorbed doses at brain, skin above the TMJ, parotid gland, bone marrow in the mandibular body, and thyroid gland during the full-mouth periapical radiography, panoramic radiography, and zonography were measured. From the zonography, the absorbed doses to the brain, the skin over the TMJ, and the parotid gland were relatively high, but the absorbed doses to the bone marrow in the mandibular body and, especially, the thyroid gland were very low. The zonography can be an alternative to the full-mouth periapical radiography in aspect of radiation protection.

  16. Absorbed dose in the full-mouth periapical radiography, panoramic radiography, and zonography

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Soon Chul; Choi, Hang Moon [Dept. of Oral and Maxillofacial Radiology and Dental Research Institute, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1999-02-15

    The objective of this study was to evaluate the possibility of substitution of the zonography for the full-mouth periapical radiography in aspect of radiation protection. Rando phantom and LiF TLD chips were used for dosimetry. The absorbed doses at brain, skin above the TMJ, parotid gland, bone marrow in the mandibular body, and thyroid gland during the full-mouth periapical radiography, panoramic radiography, and zonography were measured. From the zonography, the absorbed doses to the brain, the skin over the TMJ, and the parotid gland were relatively high, but the absorbed doses to the bone marrow in the mandibular body and, especially, the thyroid gland were very low. The zonography can be an alternative to the full-mouth periapical radiography in aspect of radiation protection.

  17. 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)

  18. 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

  19. 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)

  20. 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)

  1. 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)

  2. 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)

  3. 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....

  4. 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)

  5. 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.

  6. 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

  7. 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

  8. 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)

  9. 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

  10. Absorbed doses in salivary and thyroid glands from panoramic radiography and cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Katia Regina Heiden

    2018-02-01

    Full Text Available Abstract Introduction: Panoramic radiography and cone beam computed tomography (CBCT are very important in the diagnosis of oral diseases, however patients are exposed to the risk of ionizing radiation. This paper describes our study aimed at comparing absorbed doses in the salivary glands and thyroid due to panoramic radiography and CBCT and estimating radiation induced cancer risk associated with those methods. Methods Absorbed doses of two CBCT equipment (i-CAT® Next Generation and SCANORA® 3D and a digital panoramic device (ORTHOPANTOMOGRAPH® OP200D were measured using thermoluminescent dosimeters loaded in an anthropomorphic phantom on sublingual, submandibular, parotid and thyroid glands. Results Absorbed doses in the i-CAT® device ranged between 0.02 (+/-0.01 and 2.23 mGy (+/-0.03, in the SCANORA™ device ranged from 0.01 (+/-0.01 to 2.96 mGy (+/-0.29 and in the ORTHOPANTOMOGRAPH® OP200D ranged between 0.04 mGy and 0.78 mGy. The radiation induced cancer risk was highlighted in the salivary glands, which received higher doses. The protocols that offer the highest risk of cancer are the high resolution protocols of CBCT equipment. Conclusion CBCT exposes patients to higher levels of radiation than panoramic radiography, so the risks and benefits of each method should be considered. The doses in CBCT were dependent on equipment and exposure parameters, therefore adequate selection minimizes the radiation dose.

  11. Reduced radiation-absorbed dose to tissues with partial panoramic radiography for evaluation of third molars

    International Nuclear Information System (INIS)

    Kircos, L.T.; Eakle, W.S.; Smith, R.A.

    1986-01-01

    The radiation-absorbed doses from panoramic radiography, distal molar radiography, and a partial panoramic radiographic technique that exposes only the third molar region to radiation are compared. Doses of radiation to the submandibular salivary gland were comparable by all three techniques, but doses of radiation to the head and neck were reduced greatly by the partial panoramic radiographic technique. Partial panoramic radiography is a diagnostically satisfactory and a radiologically safer technique for evaluation of third molar pathosis than is panoramic or distal molar radiography

  12. 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)

  13. 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)

  14. 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)

  15. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Kyung Soo; Kim, Ae Ji [Dept. of Oral Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Doh, Shi Hong [Dept. of Applied physics . National Fisheries University of Pusan Department of Radiotherapy, Pusan (Korea, Republic of); Kim, Hyun Ja [Dept. of Oral Radiology, Baptist Hospital, Pusan (Korea, Republic of); Yoo, Meong Jin [Dept. of Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

    1990-08-15

    This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

  16. 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

  17. Intercomparison Programme of Absorbed Dose for Megavoltage X-ray Teletherapy Units in Malaysia

    International Nuclear Information System (INIS)

    Norhayati Abdullah; Taiman Kadni; Siti Sara Deraman

    2016-01-01

    The objective of this study is to perform a thermoluminescent dosimetry (TLD) postal dose quality audit for megavoltage X-ray teletherapy units in Malaysia. This audit is essential to be carried out to ensure adequate precision in the dosimetry of clinical beams before being delivered to the patients. Through this work, participating centres were requested to irradiate three capsules of TLD-100 powder with an absorbed dose to water of 2 Gy for 6 MV and 10 MV photon beams. The International Atomic Energy Agency (IAEA)s Technical Report Series No. 398 is used as a reference standard for TLD irradiation. A total of 22 photon beams from ten radiotherapy centres comprising one government hospital and nine private medical centres were evaluated. The percentage deviation of users measured absorbed dose relative to Secondary Standard Dosimetry Laboratory (SSDL) mean absorbed dose was calculated. The results showed that all photon beams are within the IAEA acceptance limit of ±5 % except six photon beams. These centres were followed up with a second round of TLD irradiation which resulted in a better compliance. As a conclusion, regular audits should be performed to ensure consistency of radiotherapy treatment unit performances thus maintaining the accuracy of dose delivered to patients in all radiotherapy centres in Malaysia. (author)

  18. The Effect of Diagnostic Absorbed Doses from 131I on Human Thyrocytes in Vitro

    Directory of Open Access Journals (Sweden)

    Zbigniew Adamczewski

    2015-06-01

    Full Text Available Background: Administration of diagnostic activities of 131I, performed in order to detect thyroid remnants after surgery and/or thyroid cancer recurrence/metastases, may lead to reduction of iodine uptake. This phenomenon is called “thyroid stunning”. We estimated radiation absorbed dose-dependent changes in genetic material, in particular in sodium iodide symporter (NIS gene promoter, and NIS protein level in human thyrocytes (HT. Materials and Methods: We used unmodified HT isolated from patients subjected to thyroidectomy exposed to 131I in culture. The different 131I activities applied were calculated to result in absorbed doses of 5, 10, and 20 Gy. Results: According to flow cytometry analysis and comet assay, 131I did not influence the HT viability in culture. Temporary increase of 8-oxo-dG concentration in HT directly after 24 h (p < 0.05 and increase in the number of AP-sites 72 h after termination of exposition to 20 Gy dose (p < 0.0001 were observed. The signs of dose-dependent DNA damage were not associated with essential changes in the NIS expression on mRNA and protein levels. Conclusions: Our observation constitutes a first attempt to evaluate the effect of the absorbed dose of 131I on HT. The results have not confirmed the theory that the “thyroid stunning” reduces the NIS protein synthesis.

  19. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

    International Nuclear Information System (INIS)

    Nah, Kyung Soo; Kim, Ae Ji; Doh, Shi Hong; Kim, Hyun Ja; Yoo, Meong Jin

    1990-01-01

    This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

  20. Biological dosimetry for the reconstruction of doses absorbed during accidents in radiotherapy

    International Nuclear Information System (INIS)

    Wojcik, A.; Stephan, G.; Sommer, S.; Urbanik, W.; Kukolowicz, P.; Kuszewski, T.; Gozdz, S.

    2002-01-01

    Medical radiation represents by far the largest man-made source of radiation exposure. The recent accident in a radiotherapy unit in Bialystok, Poland, clearly showed the necessity to develop biological methods allowing a reconstruction of the absorbed dose in case of an accidental exposure. We are currently analysing the frequencies of micronuclei in lymphocytes of patients undergoing radiotherapy of tumors localized in different parts of the body. The aim of the studies in the setting up to appropriate calibration curves with the help of which a dose absorbed during an accident could be estimated. In addition, the applicability of such calibration curves for quality assurance of teleradiotherapy will be considered. In order to calculate the expected frequencies of aberrations and micronuclei in lymphocytes of patients undergoing teleradiotherapy a mathematical model was developed. The modeled dose-response curves agree well with the majority of published experimental results and will serve as a basis for ongoing studies. (author)

  1. 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

  2. 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)

  3. 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

  4. 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)

  5. 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.

  6. Comparative determination of absorbed doses for high-energy photon beam with different cylindrical chambers

    International Nuclear Information System (INIS)

    Yao Xinghong; Chen Lixin; Jin Guanghua

    2012-01-01

    Objective: To study the difference between the IAEA code of practice TRS-277 and TRS-398 in the determination of the absorbed dose to water for high-energy photon beams using several cylindrical chambers. Methods: For 6 different types of cylindrical chambers,the calibration factors N D,W,Q0 in terms of absorbed dose to water were calculated from the air exposure calibration factors N x , and were compared with the N D,W,Q0 measured in European standard laboratory. Accurate measurements were performed in Varian 6 MV photon beam using 6 cylindrical chambers according to TRS-277 and TRS-398. The beam quality correction factors k Q,Q0 as well as the water absorbed doses were compared. Results: For the set of chambers, the difference between N D,W,Q0 computed from N x and N D,W,Q0 obtained in European standard laboratory was 0.13%∼ 1.30%. The difference of beam quality correction factors for TRS-277 and TRS-398 was 0.09%∼0.45%. The distinction of the water absorbed doses obtained according to the two different protocols was 0.27%∼1.40%, and was primarily due to their different calibration factors. Conclusions: The discrepancy in absorbed doses determined according to two protocols using different cylindrical chambers is clinically acceptable. However, TRS-398 allows a more convenient localization of chambers,provides a more simple formulation, and offers the reduced uncertainty in the dosimetry of radiotherapy beams. (authors)

  7. 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...

  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. Evaluation of variation of voltage (kV) absorbed dose in chest CT scans

    International Nuclear Information System (INIS)

    Mendonca, Bruna G.A.; Mourao, Arnaldo P.

    2013-01-01

    Computed tomography (CT) is one of the most important diagnostic techniques images today. The increasing utilization of CT implies a significant increase of population exposure to ionizing radiation. Optimization of practice aims to reduce doses to patients because the image quality is directly related to the diagnosis. You can decrease the amount of dose to the patient, and maintain the quality of the image. There are several parameters that can be manipulated in a CT scan and these parameters can be used to reduce the energy deposited in the patient. Based on this, we analyzed the variation of dose deposited in the lungs, breasts and thyroid, by varying the supply voltage of the tube. Scans of the thorax were performed following the protocol of routine chest with constant and variable current for the same applied voltage. Moreover, a female phantom was used and thermoluminescent dosimeters (TLD-100), model bat, were used to record the specific organ doses. Scans were performed on a GE CT scanner, model 64 Discovery channels. Higher doses were recorded for the voltage of 120 kV with 200 mAs in the lungs (22.46 mGy) and thyroid (32.22 mGy). For scans with automatic mAs, variable between 100 and 440, this same tension contributed to the higher doses. The best examination in terms of the dose that was used with automatic 80 kV mAs, whose lungs and thyroid received lower dose. For the best breast exam was 100 kV. Since the increase in the 80 kV to 100 kV no impact so much the dose deposited in the lungs, it can be concluded that lowering the applied voltage to 100 kV resulted in a reduction in the dose absorbed by the patient. These results can contribute to optimizing scans of the chest computed tomography

  10. 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

  11. Biodistribution and estimation of radiation-absorbed doses in humans for 13N-ammonia PET.

    Science.gov (United States)

    Yi, Chang; Yu, Donglan; Shi, Xinchong; He, Qiao; Zhang, Xuezhen; Zhang, Xiangsong

    2015-11-01

    To evaluate the biodistribution of radiation-absorbed doses of (13)N-ammonia in healthy people. Five healthy human subjects underwent whole-body PET and CT scans after injection of 555-740 MBq of (13)N-ammonia. Five serial dynamic emission scans in each healthy volunteer were acquired. Regions of interest were drawn on the CT image and transferred to the corresponding transverse PET slice. Estimates of the radiation-absorbed doses were calculated using the medical internal radiation dosimetry method. The highest concentrations of (13)N-ammonia were found in the heart and liver, followed by pancreas, brain, spleen and stomach. The highest absorbed organ doses were to the heart wall (7.14E-03 ± 3.63E-03 mGy/MBq) and kidneys (6.02E-03 ± 3.53E-03 mGy/MBq). The effective dose (ED) was 6.58E-03 ± 1.23E-03 mSv/MBq. With these new estimates for (13)N-ammonia dosimetry, the results for Chinese people were not appreciably different from those of the previous study performed with old devices. As one of the most important myocardial perfusion PET tracers, the whole-body (13)N-ammonia PET appears to be safe for humans, yielding a relatively modest radiation burden that would allow multiple PET studies on the same subject per year.

  12. Absorbed Dose Calculations Using Mesh-based Human Phantoms And Monte Carlo Methods

    International Nuclear Information System (INIS)

    Kramer, Richard

    2011-01-01

    Health risks attributable to the exposure to ionizing radiation are considered to be a function of the absorbed or equivalent dose to radiosensitive organs and tissues. However, as human tissue cannot express itself in terms of equivalent dose, exposure models have to be used to determine the distribution of equivalent dose throughout the human body. An exposure model, be it physical or computational, consists of a representation of the human body, called phantom, plus a method for transporting ionizing radiation through the phantom and measuring or calculating the equivalent dose to organ and tissues of interest. The FASH2 (Female Adult meSH) and the MASH2 (Male Adult meSH) computational phantoms have been developed at the University of Pernambuco in Recife/Brazil based on polygon mesh surfaces using open source software tools and anatomical atlases. Representing standing adults, FASH2 and MASH2 have organ and tissue masses, body height and body mass adjusted to the anatomical data published by the International Commission on Radiological Protection for the reference male and female adult. For the purposes of absorbed dose calculations the phantoms have been coupled to the EGSnrc Monte Carlo code, which can transport photons, electrons and positrons through arbitrary media. This paper reviews the development of the FASH2 and the MASH2 phantoms and presents dosimetric applications for X-ray diagnosis and for prostate brachytherapy.

  13. Absorbed Dose Calculations Using Mesh-based Human Phantoms And Monte Carlo Methods

    Science.gov (United States)

    Kramer, Richard

    2011-08-01

    Health risks attributable to the exposure to ionizing radiation are considered to be a function of the absorbed or equivalent dose to radiosensitive organs and tissues. However, as human tissue cannot express itself in terms of equivalent dose, exposure models have to be used to determine the distribution of equivalent dose throughout the human body. An exposure model, be it physical or computational, consists of a representation of the human body, called phantom, plus a method for transporting ionizing radiation through the phantom and measuring or calculating the equivalent dose to organ and tissues of interest. The FASH2 (Female Adult meSH) and the MASH2 (Male Adult meSH) computational phantoms have been developed at the University of Pernambuco in Recife/Brazil based on polygon mesh surfaces using open source software tools and anatomical atlases. Representing standing adults, FASH2 and MASH2 have organ and tissue masses, body height and body mass adjusted to the anatomical data published by the International Commission on Radiological Protection for the reference male and female adult. For the purposes of absorbed dose calculations the phantoms have been coupled to the EGSnrc Monte Carlo code, which can transport photons, electrons and positrons through arbitrary media. This paper reviews the development of the FASH2 and the MASH2 phantoms and presents dosimetric applications for X-ray diagnosis and for prostate brachytherapy.

  14. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment

    International Nuclear Information System (INIS)

    Barbosa, Isvania Maria Serafim da Silva

    2003-02-01

    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with 60 Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  15. 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)

  16. 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)

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

    Science.gov (United States)

    Wrzesień, Małgorzata; Olszewski, Jerzy

    2017-07-17

    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). 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. 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. 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. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  18. 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

  19. Absorbed doses for internal radiotherapy from 22 beta-emitting radionuclides: beta dosimetry of small spheres

    Energy Technology Data Exchange (ETDEWEB)

    Bardies, Manuel; Chatal, J.-F. (Institut National de la Sante et de la Recherche Medicals (INSERM), 44 - Nantes (France). Group Biophysique-Cancerologie)

    1994-06-01

    We calculated the mean absorbed fractions, specific absorbed fractions and mean doses per unit of cumulated activity in source spheres 10 [mu]m-2 cm in radius for 22 beta-emitting radionuclides potentially useful in radioimmunotherapy. We considered two models of radionuclide distribution, either uniform at the surface of the source or throughout its volume. For each model, we calculated both the absorbed fractions in the spherical segments composing the source and the mean absorbed fractions. For surface distribution, we calculated the mean dose per unit of cumulated activity for a concentric sphere with a small radius (5 [mu]m) in order to determine the minimal dose delivered to the target. Calculations were performed using point kernels for monoenergetic emissions and then integrated into the beta spectra of the different emitters ([sup 32]P, [sup 33]P, [sup 47]Sc, [sup 67]Cu, [sup 77]As, [sup 90]Y, [sup 105]Rh, [sup 109]Pd, [sup 111]Ag, [sup 121]Sn, [sup 131]I, [sup 142]Pr, [sup 143]Pr, [sup 149]Pm, [sup 153]Sm, [sup 159]Gd, [sup 166]Ho, [sup 177]Lu, [sup 186]Re, [sup 188]Re, [sup 194]Ir and [sup 199]Au). Monoenergetic emissions were taken into account. (author).

  20. Absorbed doses for internal radiotherapy from 22 beta-emitting radionuclides: beta dosimetry of small spheres.

    Science.gov (United States)

    Bardiès, M; Chatal, J F

    1994-06-01

    We calculated the mean absorbed fractions, specific absorbed fractions and mean doses per unit of cumulated activity in source spheres 10 microm-2 cm in radius for 22 beta-emitting radionuclides potentially useful in radioimmunotherapy. We considered two models of radionuclide distribution, either uniform at the surface of the source or throughout its volume. For each model, we calculated both the absorbed fractions in the spherical segments composing the source and the mean absorbed fractions. For surface distribution, we calculated the mean dose per unit of cumulated activity for a concentric sphere with a small radius (5 microm) in order to determine the minimal dose delivered to the target. Calculations were performed using point kernels for monoenergetic emissions and then integrated into the beta spectra of the different emitters (32p, 33p, 47Sc, 67Cu, 77As, 90Y, 105Rh, 109Pd, 111Ag, 121Sn, 131I, 142Pr, 143Pr, 149Pm, 153Sm, 159Gd, 166Ho, 177Lu, 186Re, 188Re, 194Ir and 199Au). Monoenergetic emissions were taken into account. Results are reported in the form of tables to facilitate use during dosimetric studies for radioimmunotherapy. An application is presented showing the potential utility of associating emitters with different energies in order to sterilize a range of tumour targets of variable size.

  1. Determination of absorbed dose in a proton beam for purposes of charged-particle radiation therapy

    International Nuclear Information System (INIS)

    Verhey, L.J.; Koehler, A.M.; McDonald, J.C.; Goitein, M.; Ma, I.C.; Schneider, R.J.; Wagner, M.

    1979-01-01

    Four methods are described by which absorbed dose has been measured in a proton beam extracted from the 160-MeV Harvard cyclotron. The standard dosimetry, used to determine doses for patient treatments, is based upon an absolute measurement of particle flux using a Faraday cup. Measurements have also been made using a parallel-plate ionization chamber; a thimble ionization chamber carying a 60 Co calibration traceable to NBS; and a tissue-equivalent calorimeter. The calorimeter, which provides an independent check of the dosimetry, agreed with the standard dosimetry at five widely different depths within a range from 0.8 to 2.6%

  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. Leukocyte DNA damage after reduced and conventional absorbed radiation doses using 3rd generation dual-source CT technology

    Directory of Open Access Journals (Sweden)

    Henning D. Popp

    2016-01-01

    Conclusion: Our results provide evidence that reduced absorbed doses mediated by adjusted tube current in 3rd generation DSCT induce lower levels of DNA damage in PBMC compared to conventional absorbed doses suggesting a lower genotoxic risk for state-of-the-art tube current reduced CT protocols.

  4. 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)

  5. Absorbed dose assessment in particle-beam irradiated metal-oxide and metal-nonmetal memristors

    Directory of Open Access Journals (Sweden)

    Knežević Ivan D.

    2012-01-01

    Full Text Available Absorbed dose was estimated after Monte Carlo simulation of proton and ion beam irradiation on metal-oxide and metal-nonmetal memristors. A memristive device comprises two electrodes, each of a nanoscale width, and a double-layer active region disposed between and in electrical contact with electrodes. Following materials were considered for the active region: titanium dioxide, zirconium dioxide, hafnium dioxide, strontium titanium trioxide and galium nitride. Obtained results show that significant amount of oxygen ion - oxygen and nonmetal ion - nonmetal vacancy pairs is to be generated. The loss of such vacancies from the device is believed to deteriorate the device performance over time. Estimated absorbed dose values in the memristor for different constituting materials are of the same order of magnitude because of the close values of treshold displacement energies for the investigated materials.

  6. 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.

  7. Optimization algorithm for absorbed dose calculation during single intake of 131І to rats

    Directory of Open Access Journals (Sweden)

    I. P. Drozd

    2016-02-01

    Full Text Available Original calculation algorithms are proposed for absorbed doses in the thyroid gland and thymus of rats at single income of 131I that enable to simplify the calculations and at the same time ensure high reliability of results in the range of input activities of 1 - 115000 Bq. According to the algorithms, the program is developed in the MATLAB environment, adapted for use on Windows running PC. Relative error of calculations is ±2 %.

  8. Measurement of absorbed doses in a homogeneous β rays fields with an extrapolation chamber

    International Nuclear Information System (INIS)

    1983-07-01

    The main characteristics of a variable cavity ionization chamber are described. Using the ionization current of the detector irradiated in homogeneous β rays fields, the tissue absorbed dose is determined. The corrective factors required to compute this quantity are analysed. Finally, international recommandations (ISO standards) relating to β rays reference fields are given, with the characteristics of β sources required for the energy response study of radiation protection instruments [fr

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

    OpenAIRE

    Wrzesien, Małgorzata; Olszewski, Jerzy

    2017-01-01

    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...

  10. Distribution of absorbed dose in human eye simulated by SRNA-2KG computer code

    International Nuclear Information System (INIS)

    Ilic, R.; Pesic, M.; Pavlovic, R.; Mostacci, D.

    2003-01-01

    Rapidly increasing performances of personal computers and development of codes for proton transport based on Monte Carlo methods will allow, very soon, the introduction of the computer planning proton therapy as a normal activity in regular hospital procedures. A description of SRNA code used for such applications and results of calculated distributions of proton-absorbed dose in human eye are given in this paper. (author)

  11. Analyse of the international recommendations on the calculation of absorbed dose in the biota

    International Nuclear Information System (INIS)

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

    2011-01-01

    This paper evaluates the recommendations of ICRP which has as objective the environmental radioprotection. It was analysed the recommendations 26, 60, 91, 103 and 108 of the ICRP. The ICRP-103 defined the concept of animal and plant of reference (APR) to be used in the RAP based on the calculation of absorbed dose based on APR concept. This last view allows to build a legal framework of environmental protection with a etic, moral and scientific visualization, more defensible than the anthropomorphic concept

  12. Biodistribution parameters and radiation absorbed dose estimates for radiolabeled human low density lipoprotein

    International Nuclear Information System (INIS)

    Hay, R.V.; Ryan, J.W.; Williams, K.A.; Atcher, R.W.; Brechbiel, M.W.; Gansow, O.A.; Fleming, R.M.; Stark, V.J.; Lathrop, K.A.; Harper, P.V.

    1992-01-01

    The authors propose a model to generate radiation absorbed dose estimates for radiolabeled low density lipoprotein (LDL), based upon eight studies of LDL biodistribution in three adult human subjects. Autologous plasma LDL was labeled with Tc-99m, I-123, or In-111 and injected intravenously. Biodistribution of each LDL derivative was monitored by quantitative analysis of scintigrams and direct counting of excreta and of serial blood samples. Assuming that transhepatic flux accounts for the majority of LDL clearance from the bloodstream, they obtained values of cumulated activity (A) and of mean dose per unit administered activity (D) for each study. In each case highest D values were calculated for liver, with mean doses of 5 rads estimated at injected activities of 27 mCi, 9 mCi, and 0.9 mCi for Tc-99m-LDL, I-123-LDL, and In-111-LDL, respectively

  13. Modeling the absorbed dose to the common carotid arteries following radioiodine treatment of benign thyroid disease

    International Nuclear Information System (INIS)

    La Cour, Jeppe Lerche; Jensen, Lars Thorbjorn; Hedemann-Jensen, Per; Sogaard-Hansen, Jens; Nygaard, Birte

    2013-01-01

    External fractionated radiotherapy of cancer increases the risk of cardio- and cerebrovascular events, but less attention has been paid to the potential side effects on the arteries following internal radiotherapy with radioactive iodine (RAI), i.e. 131-iodine. About 279 per million citizens in the western countries are treated each year with RAI for benign thyroid disorders (about 140,000 a year in the EU), stressing that it is of clinical importance to be aware of even rare radiation-induced side effects. In order to induce or accelerate atherosclerosis, the dose to the carotid arteries has to exceed 2 Gy which is the known lower limit of ionizing radiation to affect the endothelial cells and thereby to induce atherosclerosis. To estimate the radiation dose to the carotid arteries following RAI therapy of benign thyroid disorders. Assuming that the lobes of the thyroid gland are ellipsoid, that the carotid artery runs through a part of the lobes, that there is a homogeneous distribution of RAI in the lobes, and that the 24 h RAI uptake in the thyroid is 35% of the 131 I orally administrated, we used integrated modules for bioassay analysis and Monte Carlo simulations to calculate the dose in Gy/GBq of administrated RAI. The average radiation dose along the arteries is 4-55 Gy/GBq of the 131 I orally administrated with a maximum dose of approximately 25-85 Gy/GBq. The maximum absorbed dose rate to the artery is 4.2 Gy/day per GBq 131 I orally administrated. The calculated radiation dose to the carotid arteries after RAI therapy of benign thyroid disorder clearly exceeds the 2 Gy known to affect the endothelial cells and properly induce atherosclerosis. This simulation indicates a relation between the deposited dose in the arteries following RAI treatment and an increased risk of atherosclerosis and subsequent cerebrovascular events such as stroke. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Flor, Rita de Cassia [Instituto Federal de Santa Catarina (IFSC), Florianopolis, SC (Brazil); Pereira, Aline Garcia, E-mail: aalinegp@gmail.co [Sinan Project - Sistema de Informacao de Agravos de Notificacao, Florianopolis, SC (Brazil)

    2011-03-15

    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)

  15. 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

  16. 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)

  17. 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

  18. Absorbed photon dose measurement and calculation for some patient organs examined by computed tomography

    Science.gov (United States)

    Shousha, Hany A.

    Patient doses from computed tomography (CT) examinations are usually expressed in terms of dose index, organ doses, and effective dose. The CT dose index (CTDI) can be measured free-in-air or in a CT dosimetry phantom. Organ doses can be measured directly in anthropomorphic Rando phantoms using thermoluminescent detectors. Organ doses can also be calculated by the Monte Carlo method utilizing measured CTDI values. In this work, organ doses were assessed for three main CT examinations: head, chest, and abdomen, using the different mentioned methods. Results of directly measured doses were compared with calculated doses for different organs in the study, and also compared with published international studies.

  19. 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

  20. 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

  1. 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

  2. Absorbed dose distributions from ophthalmic106Ru/106Rh plaques measured in water with radiochromic film.

    Science.gov (United States)

    Hermida-López, Marcelino; Brualla, Lorenzo

    2018-02-05

    Brachytherapy with 106 Ru/ 106 Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of 106 Ru/ 106 Rh plaques used solid phantoms. This work aims to develop a practical method for measuring the absorbed dose distribution in water produced by 106 Ru/ 106 Rh plaques using EBT3 radiochromic film. Experimental setups were developed to determine the dose distribution at a plane perpendicular to the symmetry axis of the plaque and at a plane containing the symmetry axis. One CCA and two CCX plaques were studied. The dose maps were obtained with the FilmQA Pro 2015 software, using the triple-channel dosimetry method. The measured dose distributions were compared to published Monte Carlo simulation and experimental data. A good agreement was found between measurements and simulations, improving upon published data. Measured reference dose rates agreed within the experimental uncertainty with data obtained by the manufacturer using a scintillation detector, with typical differences below 5%. The attained experimental uncertainty was 4.1% (k = 1) for the perpendicular setup, and 7.9% (k = 1) for the parallel setup. These values are similar or smaller than those obtained by the manufacturer and other authors, without the need of solid phantoms that are not available to most users. The proposed method may be useful to the users to perform quality assurance preclinical tests of 106 Ru/ 106 Rh plaques. © 2018 American Association of Physicists in Medicine.

  3. Evaluation of patient absorbed dose in a PET-CT test

    International Nuclear Information System (INIS)

    Guerra P, F.; Mourao F, A. P.; Santana, P. C.

    2017-10-01

    Images of PET-CT has important diagnostic applications, especially in oncology. This equipment allows overlapping of functional images obtained from the administration of radionuclides and anatomical, generated by X-rays. The PET-CT technique may generate higher doses in patients due to the fact that two diagnostic modalities are used in a single examination. A whole body CT scan is performed and in sequence, a capture of the signal generated by the photons emitted is done. In this study, the absorbed and effective doses generated by the CT scan and incorporated by the administration of the radionuclide were evaluated in 19 organs. To evaluate the CT dose, 32 radiochromic film strips were correctly positioned into the anthropomorphic male phantom. The CT protocol performed was whole-body scanning and a high-resolution lung scan. This protocol is currently used in most services. The calculation of the effective dose from the injected activity in the patient was performed using the ICRP 106 Biokinetic model (ICRP 106, 2008). The activity to be injected may vary according to the patients body mass and with the sensitivity of the detector. The mass of the simulator used is 73.5 kg, then the simulation with and injected activity of 244.76 MBq was used. It was observed that 87.4% of the effective dose in examination PET/CT comes from the CT scans, being 63.8% of the whole body scan and 23.6% of high resolution lung scan. Using activity of 0.09 mCi x kg 18 F-FDG radiopharmaceutical contributes only 12.6% of the final effective dose. As a conclusion, it was observed that the dose in patients submitted to the 18 F-FDG PET-CT examination is high, being of great value efforts for its reduction, such as the use of appropriate image acquisition techniques and promoting the application of the principle of optimization of practice. (Author)

  4. 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 60 Co γ radiation field show that photo-cell BBZSGD-4 has good response to 60 Co 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 60 Co γ radiation field. (authors)

  5. Evaluation of 99Mo/99mTc generator columns after irradiation with different absorbed doses

    International Nuclear Information System (INIS)

    Fukumori, Neuza T.O.; Mengatti, Jair; Matsuda, Margareth M.N.

    2017-01-01

    The 99 Mo/ 99m Tc generator is widely used in nuclear medicine and it consists of a glass column containing Teflon® strips and alumina in which 99 Mo produced by 235 U fission is adsorbed. The 99 mTcO4- eluate shall meet the sterile and pyrogen free conditions for injectable radiopharmaceuticals as determined by the Good Manufacturing Practices. The purpose of this study was to evaluate the feasibility of using gamma radiation in the sterilization of the 99 Mo/ 99m Tc generator column and the influence on the elution efficiency. Alumina-containing columns were irradiated with 10, 15, 25 and 50 kGy absorbed doses. Alumina samples and control (non-irradiated) were submitted to X-ray diffraction and the combined use of scanning electron microscopy and elemental analysis. Teflon® samples were evaluated by thermogravimetry (TGA) and differential scanning calorimetry (DSC). X-ray diffractograms and micrographies with elemental analysis showed no significant changes in the crystalline structure of the alumina because it was stable α-Al 2 O 3 . TGA demonstrated that higher doses showed changes in lower temperatures and times than the control material. For DSC the higher the absorbed dose, the greater the polymer chain breakage and crosslinking in the material. The generator system without radioactivity was set up with the irradiated columns and the eluates demonstrated to be sterile and pyrogen free. The effects of different absorbed doses on the generator column, although some reported changes in the materials, demonstrated that the sterilization of the columns by irradiation with gamma rays as an alternative to wet heat sterilization is feasible from a technical and financial point of view. (author)

  6. Absorbed organ and effective doses from digital intra-oral and panoramic radiography applying the ICRP 103 recommendations for effective dose estimations.

    Science.gov (United States)

    Granlund, Christina; Thilander-Klang, Anne; Ylhan, Betȕl; Lofthag-Hansen, Sara; Ekestubbe, Annika

    2016-10-01

    During dental radiography, the salivary and thyroid glands are at radiation risk. In 2007, the International Commission on Radiological Protection (ICRP) updated the methodology for determining the effective dose, and the salivary glands were assigned tissue-specific weighting factors for the first time. The aims of this study were to determine the absorbed dose to the organs and to calculate, applying the ICRP publication 103 tissue-weighting factors, the effective doses delivered during digital intraoral and panoramic radiography. Thermoluminescent dosemeter measurements were performed on an anthropomorphic head and neck phantom. The organ-absorbed doses were measured at 30 locations, representing different radiosensitive organs in the head and neck, and the effective dose was calculated according to the ICRP recommendations. The salivary glands and the oral mucosa received the highest absorbed doses from both intraoral and panoramic radiography. The effective dose from a full-mouth intraoral examination was 15 μSv and for panoramic radiography, the effective dose was in the range of 19-75 μSv, depending on the panoramic equipment used. The effective dose from a full-mouth intraoral examination is lower and that from panoramic radiography is higher than previously reported. Clinicians should be aware of the higher effective dose delivered during panoramic radiography and the risk-benefit profile of this technique must be assessed for the individual patient. The effective dose of radiation from panoramic radiography is higher than previously reported and there is large variability in the delivered radiation dosage among the different types of equipment used.

  7. 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

  8. 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)

  9. {sup 99m}Tc Auger electrons - Analysis on the effects of low absorbed doses by computational methods

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Adriana Alexandre S., E-mail: adriana_tavares@msn.co [Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, S/N, 4200-465 Porto (Portugal); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.p [Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, S/N, 4200-465 Porto (Portugal)

    2011-03-15

    We describe here the use of computational methods for evaluation of the low dose effects on human fibroblasts after irradiation with Technetium-99m ({sup 99m}Tc) Auger electrons. The results suggest a parabolic relationship between the irradiation of fibroblasts with {sup 99m}Tc Auger electrons and the total absorbed dose. Additionally, the results on very low absorbed doses may be explained by the bystander effect, which has been implicated on the cell's effects at low doses. Further in vitro evaluation will be worthwhile to clarify these findings.

  10. 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

  11. FLUKA predictions of the absorbed dose in the HCAL Endcap scintillators using a Run1 (2012) CMS FLUKA model

    CERN Document Server

    CMS Collaboration

    2016-01-01

    Estimates of absorbed dose in HCAL Endcap (HE) region as predicted by FLUKA Monte Carlo code. Dose is calculated in an R-phi-Z grid overlaying HE region, with resolution 1cm in R, 1mm in Z, and a single 360 degree bin in phi. This allows calculation of absorbed dose within a single 4mm thick scintillator layer without including other regions or materials. This note shows estimates of the cumulative dose in scintillator layers 1 and 7 during the 2012 run.

  12. Irradiation of ferrous ammonium sulfate for its use as high absorbed dose and low-temperature dosimeter

    International Nuclear Information System (INIS)

    Juarez-Calderon, J.M.; Negron-Mendoza, A.; Ramos-Bernal, S.

    2007-01-01

    In the present paper, we study the response of crystalline ammonium ferrous sulfate as a function of the irradiation dose and temperature. The dose studied ranged from 33.5 to 546 kGy. The temperature regimen varied from 77 K (liquid nitrogen) to 311 K. The analysis of the samples was made by UV spectroscopy and EPR. The results show that the change in absorbance of the dosimeter was linear with respect to the absorbed dose in the range studied. There is a small influence of the irradiation temperature in the response of the iron salt. The dose rate and storage time after irradiation was of no importance in this application

  13. Absorbed dose determination using experimental and analytical predictions of x-ray spectra

    Science.gov (United States)

    Edwards, David Lee

    1999-10-01

    Electron beam welding in a vacuum is a technology that NASA is investigating as a joining technique for manufacture of space structures. The interaction of energetic electrons with metal produces x-rays. This investigation characterizes the x-ray environment due to operation of an in-vacuum electron beam welding tool and provides recommendations for adequate radiation shielding for astronauts performing the in-vacuum electron beam welding. NASA, in a joint venture with the Russian Space Agency, was scheduled to perform a series of welding in space experiments on board the United States Space Shuttle. This series of experiments was named the International Space Welding Experiment (ISWE). The hardware associated with the ISWE was leased to NASA, by the Paton Welding Institute (PWI) in Ukraine, for ground based welding experiments in preparation for flight. Two ground tests were scheduled, using the ISWE electron beam welding tool, to characterize the radiation exposure to an astronaut during the operation of the ISWE. These radiation exposure tests used Thermoluminescence Dosimeters (TLD's) shielded with material currently used by astronauts during Extra Vehicular Activities (EVA) to measure the radiation dose. The TLD's were exposed to x- ray radiation generated by operation of the ISWE in- vacuum electron beam welding tool. This investigation was the first known application of TLD's to measure absorbed dose from x-rays of energy less than 10 keV. The ISWE hardware was returned to Ukraine before the issue of adequate shielding for the astronauts was completely verified. Therefore alternate experimental and analytical methods were developed to measure and predict the x-ray spectral and intensity distribution generated by ISWE electron beam impact with metal. These x-ray spectra were normalized to an equivalent ISWE exposure then used to calculate the absorbed radiation dose to astronauts. These absorbed dose values were compared to TLD measurements obtained during

  14. 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

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

    Science.gov (United States)

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

    1989-06-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-06-01

    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.

  17. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K. [Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 (Japan); Ishiguchi, T. [Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 (Japan); Maekoshi, H. [Department of Radiological Technology, Nagoya University College of Medical Technology, Nagoya (Japan); Ando, Y. [Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 (Japan); Tsuzaka, M. [Department of Radiological Technology, Nagoya University College of Medical Technology, Nagoya (Japan); Tamiya, T. [Department of Radiological Technology, Nagoya University College of Medical Technology, Nagoya (Japan); Suganuma, N. [Department of Obstetrics and Gynecology, Branch Hospital, Nagoya University School of Medicine, Nagoya (Japan); Ishigaki, T. [Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 (Japan)

    1996-08-01

    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.

  19. Theoretical estimation of absorbed dose to organs in radioimmunotherapy using radionuclides with multiple unstable daughters

    International Nuclear Information System (INIS)

    Hamacher, K.A.; Sgouros, G.

    2001-01-01

    The toxicity and clinical utility of long-lived alpha emitters such as Ac-225 and Ra-223 will depend upon the fate of alpha-particle emitting unstable intermediates generated after decay of the conjugated parent. For example, decay of Ac-225 to a stable element yields four alpha particles and seven radionuclides. Each of these progeny has its own free-state biodistribution and characteristic half-life. Therefore, their inclusion for a more accurate prediction of absorbed dose and potential toxicity requires a formalism that takes these factors into consideration as well. To facilitate the incorporation of such intermediates into the dose calculation, a previously developed methodology (model 1) has been extended. Two new models (models 2 and 3) for allocation of daughter products are introduced and are compared with the previously developed model. Model 1 restricts the transport to a function that yields either the place of origin or the place(s) of biodistribution depending on the half-life of the parent radionuclide. Model 2 includes the transient time within the bloodstream and model 3 incorporates additional binding at or within the tumor. This means that model 2 also allows for radionuclide decay and further daughter production while moving from one location to the next and that model 3 relaxes the constraint that the residence time within the tumor is solely based on the half-life of the parent. The models are used to estimate normal organ absorbed doses for the following parent radionuclides: Ac-225, Pb-212, At-211, Ra-223, and Bi-213. Model simulations are for a 0.1 g rapidly accessible tumor and a 10 g solid tumor. Additionally, the effects of varying radiolabled carrier molecule purity and amount of carrier molecules, as well as tumor cell antigen saturation are examined. The results indicate that there is a distinct advantage in using parent radionuclides such as Ac-225 or Ra-223, each having a half-life of more than 10 days and yielding four alpha

  20. 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.

  1. 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)

  2. 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

  3. Absorbed dose measurements in mammography using Monte Carlo method and ZrO2+PTFE dosemeters

    International Nuclear Information System (INIS)

    Duran M, H. A.; Hernandez O, M.; Salas L, M. A.; Hernandez D, V. M.; Vega C, H. R.; Pinedo S, A.; Ventura M, J.; Chacon, F.; Rivera M, T.

    2009-10-01

    Mammography test is a central tool for breast cancer diagnostic. In addition, programs are conducted periodically to detect the asymptomatic women in certain age groups; these programs have shown a reduction on breast cancer mortality. Early detection of breast cancer is achieved through a mammography, which contrasts the glandular and adipose tissue with a probable calcification. The parameters used for mammography are based on the thickness and density of the breast, their values depend on the voltage, current, focal spot and anode-filter combination. To achieve an image clear and a minimum dose must be chosen appropriate irradiation conditions. Risk associated with mammography should not be ignored. This study was performed in the General Hospital No. 1 IMSS in Zacatecas. Was used a glucose phantom and measured air Kerma at the entrance of the breast that was calculated using Monte Carlo methods and ZrO 2 +PTFE thermoluminescent dosemeters, this calculation was completed with calculating the absorbed dose. (author)

  4. 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.

  5. Mercury exposure from dental amalgam fillings: absorbed dose and the potential for adverse health effects.

    Science.gov (United States)

    Mackert, J R; Berglund, A

    1997-01-01

    This review examines the question of whether adverse health effects are attributable to amalgam-derived mercury. The issue of absorbed dose of mercury from amalgam is addressed first. The use of intra-oral Hg vapor measurements to estimate daily uptake must take into account the differences between the collection volume and flow rate of the measuring instrument and the inspiratory volume and flow rate of air through the mouth during inhalation of a single breath. Failure to account for these differences will result in substantial overestimation of the absorbed dose. Other factors that must be considered when making estimates of Hg uptake from amalgam include the accurate measurement of baseline (unstimulated) mercury release rates and the greater stimulation of Hg release afforded by chewing gum relative to ordinary food. The measured levels of amalgam-derived mercury in brain, blood, and urine are shown to be consistent with low absorbed doses (1-3 micrograms/day). Published relationships between the number of amalgam surfaces and urine levels are used to estimate the number of amalgam surfaces that would be required to produce the 30 micrograms/g creatinine urine mercury level stated by WHO to be associated with the most subtle, pre-clinical effects in the most sensitive individuals. From 450 to 530 amalgam surfaces would be required to produce the 30 micrograms/g creatinine urine mercury level for people without any excessive gum-chewing habits. The potential for adverse health effects and for improvement in health following amalgam removal is also addressed. Finally, the issue of whether any material can ever be completely exonerated of claims of producing adverse health effects is considered.

  6. 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.

  7. CCRI supplementary comparison of standards for absorbed dose to water in {sup 60}Co gamma radiation at radiation processing dose levels

    Energy Technology Data Exchange (ETDEWEB)

    Burns, D.T. [Bureau International des Poids et Mesures, Pavillon de Breteuil, F-92312 Sevres Cedex (France)]. E-mail: dburns@bipm.org; Allisy-Roberts, P.J. [Bureau International des Poids et Mesures, Pavillon de Breteuil, F-92312 Sevres Cedex (France); Desrosiers, M.F. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Nagy, V.Yu. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Sharpe, P.H.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom); Laitano, R.F. [Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti, Rome (Italy); Mehta, K. [International Atomic Energy Agency, Vienna (Austria); Schneider, M.K.H. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Zhang, Y.L. [National Institute of Metrology, Beijing (China)

    2006-09-15

    Six national standards for absorbed dose to water in {sup 60}Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 5 to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The standards are in agreement at the level of around 0.5%, which is significantly smaller than the stated standard uncertainties.

  8. 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...

  9. The 1998 calibration of Australian secondary standards of exposure and absorbed dose at 60Co

    International Nuclear Information System (INIS)

    Huntley, R.B.; Van der Gaast, H.

    1998-10-01

    New calibration factors are reported for several of the ionization chambers maintained at the Australian Radiation Laboratory (ARL) and at the Australian Nuclear Science and Technology Organisation (ANSTO) as Australian secondary standards of exposure/air kerma and absorbed dose at 60 Co. These calibration factors supplement or replace the calibration factors given in earlier reports. Updated 90 Sr reference source data are given for the ARL chambers, and for two of the ANSTO chambers. These results confirm the stability of the secondary standards. A re-calibration of the ANSTO reference electrometer is reported. This was carried out using an improved method, which is fully described

  10. 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)

  11. 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)

  12. 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)

  13. Thyroid absorbed dose for people at Rongelap, Utirik, and Sifo on March 1, 1954

    Energy Technology Data Exchange (ETDEWEB)

    Lessard, E.T.; Miltenberger, R.P.; Conrad, R.A.; Musoline, S.V.; Naidu, J.R.; Moorthy, A.; Schopfer, C.J.

    1985-03-01

    A study was undertaken to reexamine thyroid absorbed dose estimates for people accidentally exposed to fallout at Rongelap, Sifo, and Utirik Islands from the Pacific weapon test known as Operation Castle BRAVO. The study included: (1) reevaluation of radiochemical analysis, to relate results from pooled urine to intake, retention, and excretion functions; (2) analysis of neutron-irradiation studies of archival soil samples, to estimate areal activities of the iodine isotopes; (3) analysis of source term, weather data, and meteorological functions used in predicting atmospheric diffusion and fallout deposition, to estimate airborne concentrations of the iodine isotopes; and (4) reevaluation of radioactive fallout, which contaminated a Japanese fishing vessel in the vicinity of Rongelap Island on March 1, 1954, to determine fallout components. The conclusions of the acute exposure study were that the population mean thyroid absorbed doses were 21 gray (2100 rad) at Rongelap, 6.7 gray (670 rad) at Sifo, and 2.8 gray (280 rad) at Utirik. The overall thyroid cancer risk we estimated was in agreement with results published on the Japanese exposed at Nagasaki and Hiroshima. We now postulate that the major route for intake of fallout was by direct ingestion of food prepared and consumed outdoors. 66 refs., 13 figs., 25 tabs.

  14. Thyroid absorbed dose for people at Rongelap, Utirik, and Sifo on March 1, 1954

    International Nuclear Information System (INIS)

    Lessard, E.T.; Miltenberger, R.P.; Conrad, R.A.; Musoline, S.V.; Naidu, J.R.; Moorthy, A.; Schopfer, C.J.

    1985-03-01

    A study was undertaken to reexamine thyroid absorbed dose estimates for people accidentally exposed to fallout at Rongelap, Sifo, and Utirik Islands from the Pacific weapon test known as Operation Castle BRAVO. The study included: (1) reevaluation of radiochemical analysis, to relate results from pooled urine to intake, retention, and excretion functions; (2) analysis of neutron-irradiation studies of archival soil samples, to estimate areal activities of the iodine isotopes; (3) analysis of source term, weather data, and meteorological functions used in predicting atmospheric diffusion and fallout deposition, to estimate airborne concentrations of the iodine isotopes; and (4) reevaluation of radioactive fallout, which contaminated a Japanese fishing vessel in the vicinity of Rongelap Island on March 1, 1954, to determine fallout components. The conclusions of the acute exposure study were that the population mean thyroid absorbed doses were 21 gray (2100 rad) at Rongelap, 6.7 gray (670 rad) at Sifo, and 2.8 gray (280 rad) at Utirik. The overall thyroid cancer risk we estimated was in agreement with results published on the Japanese exposed at Nagasaki and Hiroshima. We now postulate that the major route for intake of fallout was by direct ingestion of food prepared and consumed outdoors. 66 refs., 13 figs., 25 tabs

  15. 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)

  16. Measurements of spatial distribution of absorbed dose in proton therapy with Gafchromic EBT3

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G.; Regazzoni, V.; Grisotto, S.; Artuso, E.; Giove, D. [Universita degli Studi di Milano, Department of Physics, via Celoria 16, 20133 Milano (Italy); Borroni, M.; Carrara, M.; Pignoli, E. [Fondazione IRCCS, Istituto Nazionale dei Tumori di Milano, Medical Physics Unit, via Giacomo Venezian 16, 20133 Milano (Italy); Mirandola, A.; Ciocca, M., E-mail: grazia.gambarini@mi.infn.it [Centro Nazionale Adroterapia Oncologica, Medical Physics Unit, Strada Campeggi 53, 27100 Pavia (Italy)

    2014-08-15

    A study of the response of EBT3 films has been carried out. Light transmittance images (around 630 nm) were acquired by means of a Ccd camera. The difference of optical density was assumed as dosimeter response. Calibration was performed by means of {sup 60}Co photons, at a radiotherapy facility. A study of the response variation during the time after exposure has been carried out. EBT3 films were exposed, in a solid-water phantom, to proton beams of various energies and the obtained depth-dose profiles were compared with those measured with a ionization chamber. As expected, in the Bragg peak region the values obtained with EBT3 films were lower than those obtained with the ionization chamber. The ratio of such values was evaluated, along dose profiles, for each utilized energy. A method for correcting the data measured with EBT3 has been proposed and tested. The results confirm that the method can be advantageously applied for obtaining spatial distribution of the absorbed dose in proton therapy. (author)

  17. 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)

  18. Control letters and uncertainties of the kerma patterns in air, dose absorbed in water and dose absorbed in air of the LSCD

    International Nuclear Information System (INIS)

    Alvarez R, M.T.; Tovar M, V.M.; Cejudo A, J.

    2005-12-01

    With the purpose of characterizing the component of uncertainty of long term of the patron ionization chambers of the LSCD, for the magnitudes: speed of kerma in air Κ α· , dose speed absorbed in water Dα · , and speed absorbed dose in air Dα · , it use the technique of letters of control l-MR/S. This statistical technique it estimates the component of uncertainty of short term by means of the deviation standard inside groups σ ω and that of long term by means of the standard deviation among groups σ β , being this it finishes an estimator of the stability of the patterns.The letters of control l-MR/S it construct for: i) Κ α· , in radiation field of 60 Co for patterns: primary CC01 series 131, secondary NE 2611 series 176, secondary PTW TN30031 series 578 and Third PTW W30001 series 365. ii) Dα),en radiation field of 60 Co for patterns: primary CC01 series 131, Secondary PTW TN30031 series 578 and tertiary PTW W30001 series 365. iii) I-MR/S with extrapolation chamber PTW primary pattern, measurement realizes in secondary patron fields of 90 Sr- 90 Y. The expanded uncertainty U it is calculated of agreement with the Guide of the ISO/BIPM being observed the following thing: a. In some the cases σ β , is the component of the U that more contributed to this. Therefore, it is necessary to settle down technical of sampling in those mensurations that allow to reduce the value of σ β . For example with sizes of subgroup η ∼ 30 data, or with a number of subgroups κ ≥ . That which is achieved automating the mensuration processes. b.The component of the temperature is also one of those that but they contribute to the U, of there the necessity of: to recover the tracking for this magnitude of it influences and to increase the precision in the determinations of the temperature to diminish their influence in the U. c. The percentage difference of the magnitudes dosemeters carried out by it patterns are consistent with U certain. However, it is necessary

  19. 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

  20. Intercomparison of absorbed dose to water measurements for 60Co gamma rays using Fricke, alanine and radiochromic dye film dosimetry

    International Nuclear Information System (INIS)

    Villarreal-Barajas, J.E.; Gonzalez-Martinez, P.R.; Urena-Nunez, F.; Martinez-Ayala, L.; Tovar-Munoz, V.M.

    2002-01-01

    Measurements of absorbed dose at 5 cm depth in a 30 x 30 x 30 cm 3 water phantom have been performed using three independent dosimetric techniques: Fricke, alanine and radiochromic dye film (GafChromic HD-810). The measurements were carried out in the secondary standard dosimetry laboratory at ININ Mexico using a collimated 60 Co gamma source with a radiation field of 10 x 10 cm 2 at the phantom front surface. The source to phantom distance was set at 100 cm. The reference absorbed dose at 5 cm depth in the water phantom was obtained using a 0.6 cm 3 ionisation chamber. The absorbed dose to water for the test dosimetry techniques was around 100 Gy. The deviations of the dose obtained from these dosimetry techniques were within 4%. The reasons for these deviations are discussed. (author)

  1. On a Possibility of Nondisturbing Monitoring of Electron-Radiation Absorbed Dose in Radiation-Technological Processes

    International Nuclear Information System (INIS)

    Karasev, S.P.; Nikiforov, V.I.; Pomatsalyuk, R.I.; Tenishev, A.Eh.; Uvarov, V.L.; Shevchenko, V.A.; Shlyakhov, I.N.; Malets, E.B.

    2006-01-01

    Great deals of present day radiation technologies that use electron accelerators involve the procedure of transporting the products under treatment across the irradiation zone normally to the beam scanning plane. The main controlled characteristic of the process is the electron radiation dose absorbed in the object under treatment. The present paper offers the method of nonperturbing real-time dose and electron energy monitoring. The method is based on the analysis of distribution of currents from the plates of a sectionalised beam charge absorber. The absorber is placed behind the conveyor and is periodically shut off from the beam by the object under irradiation. The method was preliminary analyzed through computer simulation

  2. Supplementary comparison CCRI(I)-S2 of standards for absorbed dose to water in 60Co gamma radiation at radiation processing dose levels

    DEFF Research Database (Denmark)

    Burns, D. T.; Allisy-Roberts, P. J.; Desrosiers, M. F.

    2011-01-01

    Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized by the B......Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized...... by the Bureau International des Poids et Mesures, who also participated at the lowest dose level using their radiotherapy-level standard for the same quantity. The national standards are in general agreement within the standard uncertainties, which are in the range from 1 to 2 parts in 102. Evidence of a dose...

  3. MO-AB-BRA-03: Calorimetry-Based Absorbed Dose to Water Measurements Using Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Martinez, E; Malin, M; DeWerd, L [University of WI-Madison/ADCL, Madison, WI (United States)

    2015-06-15

    Purpose: Interferometry-based calorimetry is a novel technique to measure radiation-induced temperature changes allowing the measurement of absorbed dose to water (ADW). There are no mechanical components in the field. This technique also has the possibility of obtaining 2D dose distributions. The goal of this investigation is to calorimetrically-measure doses between 2.5 and 5 Gy over a single projection in a photon beam using interferometry and compare the results with doses calculated using the TG-51 linac calibration. Methods: ADW was determined by measuring radiation-induced phase shifts (PSs) of light passing through water irradiated with a 6 MV photon beam. A 9×9×9 cm{sup 3} glass phantom filled with water and placed in an arm of a Michelson interferometer was irradiated with 300, 400, 500 and 600 monitor units. The whole system was thermally insulated to achieve sufficient passive temperature control. The depth of measurement was 4.5 cm with a field size of 7×7 cm{sup 2}. The intensity of the fringe pattern was monitored with a photodiode and used to calculate the time-dependent PS curve. Data was acquired 60 s before and after the irradiation. The radiation-induced PS was calculated by taking the difference in the pre- and post-irradiation drifts extrapolated to the midpoint of the irradiation. Results were compared to computed doses. Results: Average comparison of calculated ADW values with interferometry-measured values showed an agreement to within 9.5%. k=1 uncertainties were 4.3% for calculations and 14.7% for measurements. The dominant source of uncertainty for the measurements was a temperature drift of about 30 µK/s caused by heat conduction from the interferometer’s surroundings. Conclusion: This work presented the first absolute ADW measurements using interferometry in the dose range of linac-based radiotherapy. Future work to improve measurements’ reproducibility includes the implementation of active thermal control techniques.

  4. 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

  5. RESPONSE FUNCTIONS FOR COMPUTING ABSORBED DOSE TO SKELETAL TISSUES FROM NEUTRON IRRADIATION

    Science.gov (United States)

    Bahadori, Amir A.; Johnson, Perry; Jokisch, Derek W.; Eckerman, Keith F.; Bolch, Wesley E.

    2016-01-01

    Spongiosa in the adult human skeleton consists of three tissues - active marrow (AM), inactive marrow (IM), and trabecularized mineral bone (TB). Active marrow is considered to be the target tissue for assessment of both long-term leukemia risk and acute marrow toxicity following radiation exposure. The total shallow marrow (TM50), defined as all tissues laying within the first 50 μm the bone surfaces, is considered to be the radiation target tissue of relevance for radiogenic bone cancer induction. For irradiation by sources external to the body, kerma to homogeneous spongiosa has been used as a surrogate for absorbed dose to both of these tissues, as direct dose calculations are not possible using computational phantoms with homogenized spongiosa. Recent microCT imaging of a 40-year-old male cadaver has allowed for the accurate modeling of the fine microscopic structure of spongiosa in many regions of the adult skeleton [Hough et al PMB (2011)]. This microstructure, along with associated masses and tissue compositions, was used to compute specific absorbed fractions (SAF) values for protons originating in axial and appendicular bone sites [Jokisch et al PMB (submitted)]. These proton SAFs, bone masses, tissue compositions, and proton production cross-sections, were subsequently used to construct neutron dose response functions (DRFs) for both AM and TM50 targets in each bone of the reference adult male. Kerma conditions were assumed for other resultant charged particles. For comparison, active marrow, total shallow marrow, and spongiosa kerma coefficients were also calculated. At low incident neutron energies, AM kerma coefficients for neutrons correlate well with values of the AM DRF, while total marrow (TM) kerma coefficients correlate well with values of the TM50 DRF. At high incident neutron energies, all kerma coefficients and DRFs tend to converge as charged particle equilibrium (CPE) is established across the bone site. In the range of 10 eV to 100 Me

  6. Absorbed dose to active red bone marrow from diagnostic and therapeutic uses of radiation

    International Nuclear Information System (INIS)

    Solomon, S.B.

    1980-06-01

    The bone-marrow dose arising from radiological procedures as carried out in Australia have been determined as part of a survey of population doses. This paper describes the method of calculation of the radiation doses to the active bone marrow from diagnostic radiography, fluoroscopy and radiotherapy. The results of the calculations are compared with the results of other models of bone-marrow dose for a number of diagnostic X-ray procedures

  7. Environmental and biological monitoring in the estimation of absorbed doses of pesticides.

    Science.gov (United States)

    Aprea, Maria Cristina

    2012-04-25

    Exposure to pesticides affects most of the population, not only persons occupationally exposed. In a context of high variability of exposure, biological monitoring is important because of the various routes by which exposure can occur and because it assesses both occupational and non-occupational exposure. The main aim of this paper was to critically compare estimates of absorbed dose measured by environmental and biological monitoring in situations in which they could both be applied. The combination of exposure measurements and biological monitoring was found to provide extremely important information on the behaviour of employees, and on the proper use and effectiveness of personal protection equipment. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  8. Radioactive caesium in a boreal forest ecosystem and internally absorbed dose to man

    International Nuclear Information System (INIS)

    Bergman, R.; Johansson, L.

    1989-01-01

    Different aspects dealing with water-soil, soil-plant and plant-herbivore interactions are studied. The study area is located to the Forest Research Station at Svartberget 50 km west of Umea in Vaesterbotten. An important topic in this study concerns the transport of caesium in food chains to man. Consumption of forest products by man i.e. game (primarily moose) and berries constitutes the major pathway of radioactive caesium to man. Moose meat contributes to about 30% of the total meat consumption in Vaesterbotten and the average over the Swedish population has remained at the level of 5-10% during the present decade. In order to assess the absorbed dose resulting from intake via these food products over a long period of time, knowledge about the long term behaviour of caesium in the biotic community is studied. (orig./HP)

  9. 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)

  10. Monte Carlo analysis of pion contribution to absorbed dose from Galactic cosmic rays

    International Nuclear Information System (INIS)

    Aghara, S.K.; Blattnig, S.R.; Norbury, J.W.; Singleterry, R.C.

    2009-01-01

    Accurate knowledge of the physics of interaction, particle production and transport is necessary to estimate the radiation damage to equipment used on spacecraft and the biological effects of space radiation. For long duration astronaut missions, both on the International Space Station and the planned manned missions to Moon and Mars, the shielding strategy must include a comprehensive knowledge of the secondary radiation environment. The distribution of absorbed dose and dose equivalent is a function of the type, energy and population of these secondary products. Galactic cosmic rays (GCR) comprised of protons and heavier nuclei have energies from a few MeV per nucleon to the ZeV region, with the spectra reaching flux maxima in the hundreds of MeV range. Therefore, the MeV-GeV region is most important for space radiation. Coincidentally, the pion production energy threshold is about 280 MeV. The question naturally arises as to how important these particles are with respect to space radiation problems. The space radiation transport code, HZETRN (High charge (Z) and Energy TRaNsport), currently used by NASA, performs neutron, proton and heavy ion transport explicitly, but it does not take into account the production and transport of mesons, photons and leptons. In this paper, we present results from the Monte Carlo code MCNPX (Monte Carlo N-Particle eXtended), showing the effect of leptons and mesons when they are produced and transported in a GCR environment.

  11. Monte Carlo analysis of pion contribution to absorbed dose from Galactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Aghara, S.K. [Prairie View A and M University, Chemical Engineering (Nuclear Program), P.O. Box 519, MS 2505, Prairie View, TX 77446 (United States)], E-mail: Sukesh.K.Aghara@nasa.gov; Blattnig, S.R.; Norbury, J.W.; Singleterry, R.C. [NASA Langley Research Center, Hampton, VA 23681 (United States)

    2009-04-15

    Accurate knowledge of the physics of interaction, particle production and transport is necessary to estimate the radiation damage to equipment used on spacecraft and the biological effects of space radiation. For long duration astronaut missions, both on the International Space Station and the planned manned missions to Moon and Mars, the shielding strategy must include a comprehensive knowledge of the secondary radiation environment. The distribution of absorbed dose and dose equivalent is a function of the type, energy and population of these secondary products. Galactic cosmic rays (GCR) comprised of protons and heavier nuclei have energies from a few MeV per nucleon to the ZeV region, with the spectra reaching flux maxima in the hundreds of MeV range. Therefore, the MeV-GeV region is most important for space radiation. Coincidentally, the pion production energy threshold is about 280 MeV. The question naturally arises as to how important these particles are with respect to space radiation problems. The space radiation transport code, HZETRN (High charge (Z) and Energy TRaNsport), currently used by NASA, performs neutron, proton and heavy ion transport explicitly, but it does not take into account the production and transport of mesons, photons and leptons. In this paper, we present results from the Monte Carlo code MCNPX (Monte Carlo N-Particle eXtended), showing the effect of leptons and mesons when they are produced and transported in a GCR environment.

  12. Development of standardized methods to verify absorbed dose of irradiated fresh and dried fruits, tree nuts in trade

    International Nuclear Information System (INIS)

    Siddiqui, A.K.; Amin, M.R.; Chowdhury, N.A.; Begum, F.; Mollah, A.S.; Mollah, R.A.; Chowdhury, A.H.

    2001-01-01

    Investigations were carried out on standardization of desired process control parameters such as dose distribution in trade containers, container standardization and development of 'label' dosimeters. A prototype 'label' dose indicators Sterins for threshold doses of 125 Gy and 300 Gy was studied. Dose distribution was studied using fresh fruits and tree nuts in trade and standardized containers with varying product densities. The distribution of absorbed doses was measured by Fricke, Gammachrome YR, clear Polymethylmethacrylate (PMMA), EthanolChlorobenzene (ECB) and Sterin 300. These values are given as Dmax/Dmin ratios in relation to product bulk densities. It was observed that bulk densities varied greatly among different products depending on the types of fruits, containers and pattern of loading which also affected dose distribution. Dmax/Dmin obtained by proper dose mapping could be kept low by arranging proper irradiation conditions which ensured uniform dose distribution. Prototype 'label' dose indicators like Sterins and clear PMMA were used for dose mapping along with the standard primary and secondary dosimeters. Sterins and clear PMMA were also studied for their dosimetric properties, particularly for use in label dosimetry. Sterins 125 and 300 evaluated visually showed their integrity at their threshold doses. The word NOT on Sterin 125 eclipsed after 115 Gy and on Sterin 300 after 270 Gy dose. Clear PMMA samples of 410 mm thickness irradiated at 200-1000 Gy showed linear response and had postirradiation stability for over a month storage at normal temperatures (21-35 deg. C) and humidities. These could be investigated further for developing as 'label' dosimeters in insect control quarantine treatment. Other low dose indicators studied such as coloured perspex, dye solutions were not found useful at quarantine dose levels. Further investigations are required for developing a 'label' dosimeter for commercial use. (author)

  13. 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

  14. 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)

  15. Dose absorbed in x-rays toraxicas executed in hospitals of the city of Sao Paulo Brazil

    International Nuclear Information System (INIS)

    Freitas, M.B.; Yoshimura, E.M.

    1998-01-01

    With the objective of evaluating the contribution of radiography exams in the dose received by the population of the city of Sao Paulo (Brazil), we made mensurations of the doses absorbed in toraxicas x-rays (projections PA and LAT) taken in several teams of rays X used in hospitals. The work is supplemented with demography data and the knowledge of the quantity of exams executed in each team

  16. The provision of national standards of absorbed dose for radiation processing. The role of NPL in the United Kingdom

    International Nuclear Information System (INIS)

    Ellis, S.C.

    1981-01-01

    The system of national and international standardization is examined, particularly with respect to the problems of standardizing high absorbed dose measurements required in processing with photons from cobalt-60 and electrons. The need for development of primary standards specifically dedicated to this application versus the possibility of extrapolation from standards in use at lower dose levels is considered together with means for dissemination and intercomparison. The present status of standards at NPL and the future programme are outlined. (author)

  17. Analyse of the international recommendations on the calculation of absorbed dose in the biota; Analise das recomendacoes internacionais sobre calculo de dose absorvida na biota

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de S.; Py Junior, Delcy de A., E-mail: wspereira@inb.gov.b, E-mail: delcy@inb.gov.b [Industrias Nucleares do Brasil (UTM/INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerios; Universidade Federal Fluminense (LARARA/UFF), Niteroi, RJ (Brazil). Lab. de Radiobiologia e Radiometria; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-Graduacao em Ciencia Ambiental

    2011-10-26

    This paper evaluates the recommendations of ICRP which has as objective the environmental radioprotection. It was analysed the recommendations 26, 60, 91, 103 and 108 of the ICRP. The ICRP-103 defined the concept of animal and plant of reference (APR) to be used in the RAP based on the calculation of absorbed dose based on APR concept. This last view allows to build a legal framework of environmental protection with a etic, moral and scientific visualization, more defensible than the anthropomorphic concept

  18. Absorbed dose due to radioiodine therapy by organs of patients with hyperthyroidism; Dose absorvida em orgaos de pacientes com hipertiroidismo devido a radioiodoterapia

    Energy Technology Data Exchange (ETDEWEB)

    Lima, F.F.; Khoury, H.J.; Bertelli Neto, L. [Pernambuco Univ., Recife, PE (Brazil); Laboratorios CERPE, Recife, PE (Brazil); Bertelli Neto, L. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

    1999-07-01

    The dose absorbed by organs of patients with hyperthyroidism treated with {sup 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 {sup 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.

  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. A new gel using super absorbent polymer for mapping the spatial dose distributions of electron beams by MR imager.

    Science.gov (United States)

    Hiraoka, T; Hoshino, K; Kawashima, K; Kato, H; Tateno, Y

    1993-01-01

    A technique for mapping the spatial dose distribution with a magnetic resonance imager is presented. A ferrous sulphate solution with sulfuric acid was used as the detecting medium for radiation dose. To make a gel of the solution for filling up a cubic phantom, we developed a new gel component that is combined with a super absorbent polymer (Sumikagel N-100) and a cross-linked dextran gel (Sephadex G-200). In order to make the application for radiation treatment planning, mapping of the dose distribution was carried out using a Unix computer.

  1. Influence of exposure and geometric parameters on absorbed doses associated with common neuro-interventional procedures.

    Science.gov (United States)

    Safari, Mohammad Javad; Wong, Jeannie Hsiu Ding; Jong, Wei Loong; Thorpe, Nathan; Cutajar, Dean; Rosenfeld, Anatoly; Ng, Kwan Hoong

    2017-03-01

    The purpose of this study was to investigate the effects of routine exposure parameters on patient's dose during neuro-interventional radiology procedures. We scrutinized the routine radiological exposure parameters during 58 clinical neuro-interventional procedures such as, exposure direction, magnification, frame rate, and distance between image receptor to patient's body and evaluate their effects on patient's dose using an anthropomorphic phantom. Radiation dose received by the occipital region, ears and eyes of the phantom were measured using MOSkin detectors. DSA imaging technique is a major contributor to patient's dose (80.9%) even though they are used sparingly (5.3% of total frame number). The occipital region of the brain received high dose largely from the frontal tube constantly placed under couch (73.7% of the total KAP). When rotating the frontal tube away from under the couch, the radiation dose to the occipital reduced by 40%. The use of magnification modes could increase radiation dose by 94%. Changing the image receptor to the phantom surface distance from 10 to 40cm doubled the radiation dose received by the patient's skin at the occipital region. Our findings provided important insights into the contribution of selected fluoroscopic exposure parameters and their impact on patient's dose during neuro-interventional radiology procedures. This study showed that the DSA imaging technique contributed to the highest patient's dose and judicial use of exposure parameters might assist interventional radiologists in effective skin and eye lens dose reduction for patients undergoing neuro-interventional procedures. Copyright © 2017 Associazione Italiana di Fisica Medica. All rights reserved.

  2. Secondary neutron dose measurement for proton eye treatment using an eye snout with a borated neutron absorber

    Science.gov (United States)

    2013-01-01

    Background We measured and assessed ways to reduce the secondary neutron dose from a system for proton eye treatment. Methods Proton beams of 60.30 MeV were delivered through an eye-treatment snout in passive scattering mode. Allyl diglycol carbonate (CR-39) etch detectors were used to measure the neutron dose in the external field at 0.00, 1.64, and 6.00 cm depths in a water phantom. Secondary neutron doses were measured and compared between those with and without a high-hydrogen–boron-containing block. In addition, the neutron energy and vertices distribution were obtained by using a Geant4 Monte Carlo simulation. Results The ratio of the maximum neutron dose equivalent to the proton absorbed dose (H(10)/D) at 2.00 cm from the beam field edge was 8.79 ± 1.28 mSv/Gy. The ratio of the neutron dose equivalent to the proton absorbed dose with and without a high hydrogen-boron containing block was 0.63 ± 0.06 to 1.15 ± 0.13 mSv/Gy at 2.00 cm from the edge of the field at depths of 0.00, 1.64, and 6.00 cm. Conclusions We found that the out-of-field secondary neutron dose in proton eye treatment with an eye snout is relatively small, and it can be further reduced by installing a borated neutron absorbing material. PMID:23866307

  3. Radiation Absorbed Dose to the Basal Ganglia from Dopamine Transporter Radioligand 18F-FPCIT

    Directory of Open Access Journals (Sweden)

    William Robeson

    2014-01-01

    Full Text Available Our previous dosimetry studies have demonstrated that for dopaminergic radiotracers, 18F-FDOPA and 18F-FPCIT, the urinary bladder is the critical organ. As these tracers accumulate in the basal ganglia (BG with high affinity and long residence times, radiation dose to the BG may become significant, especially in normal control subjects. We have performed dynamic PET measurements using 18F-FPCIT in 16 normal adult subjects to determine if in fact the BG, although not a whole organ, but a well-defined substructure, receives the highest dose. Regions of interest were drawn over left and right BG structures. Resultant time-activity curves were generated and used to determine residence times for dosimetry calculations. S-factors were computed using the MIRDOSE3 nodule model for each caudate and putamen. For 18F-FPCIT, BG dose ranged from 0.029 to 0.069 mGy/MBq. In half of all subjects, BG dose exceeded 85% of the published critical organ (bladder dose, and in three of those, the BG dose exceeded that for the bladder. The BG can become the dose-limiting organ in studies using dopamine transporter ligands. For some normal subjects studied with F-18 or long half-life radionuclide, the BG may exceed bladder dose and become the critical structure.

  4. The effect of backscattering on the beta dose absorbed by individual quartz grains

    DEFF Research Database (Denmark)

    Autzen, Martin; Guérin, G.; Murray, A. S.

    2017-01-01

    We describe the effect on dose rates and over-dispersion (OD) of changing the spectrum of energies to which grains of various shapes and volumes are exposed during beta irradiation, either by changing the backscattering medium or attenuating the incident spectrum. Dose rates are found to increase...

  5. 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)

  6. 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

  7. Cartography of absorbed doses by dosimetric textile. Testing in (n,γ) or β,γ) mixed field

    International Nuclear Information System (INIS)

    Benabdesselam, M.; Lacconi, P.; Lapraz, D.; Serbat, A.; Dhermain, J.

    1998-01-01

    When an accident due to ionising radiations occurs, it is very important to be able to map the surface cartography and to have an estimation of the dose absorbed by the irradiated persons. Since the importance of these informations, a cotton textile coated with a dosimetric alumina has been settled and studied by thermoluminescence. (author)

  8. Absorbed dose evaluation based on a computational voxel model incorporating distinct cerebral structures

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Samia de Freitas; Trindade, Bruno; Campos, Tarcisio P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)]. E-mail: samiabrandao@gmail.com; bmtrindade@yahoo.com; campos@nuclear.ufmg.br

    2007-07-01

    Brain tumors are quite difficult to treat due to the collateral radiation damages produced on the patients. Despite of the improvements in the therapeutics protocols for this kind of tumor, involving surgery and radiotherapy, the failure rate is still extremely high. This fact occurs because tumors can not often be totally removed by surgery since it may produce some type of deficit in the cerebral functions. Radiotherapy is applied after the surgery, and both are palliative treatments. During radiotherapy the brain does not absorb the radiation dose in homogeneous way, because the various density and chemical composition of tissues involved. With the intention of evaluating better the harmful effects caused by radiotherapy it was developed an elaborated cerebral voxel model to be used in computational simulation of the irradiation protocols of brain tumors. This paper presents some structures function of the central nervous system and a detailed cerebral voxel model, created in the SISCODES program, considering meninges, cortex, gray matter, white matter, corpus callosum, limbic system, ventricles, hypophysis, cerebellum, brain stem and spinal cord. The irradiation protocol simulation was running in the MCNP5 code. The model was irradiated with photons beam whose spectrum simulates a linear accelerator of 6 MV. The dosimetric results were exported to SISCODES, which generated the isodose curves for the protocol. The percentage isodose curves in the brain are present in this paper. (author)

  9. Perspectives in absorbed dose metrology with regard to the technical evolutions of external beam radiotherapy

    International Nuclear Information System (INIS)

    Chauvenet, B.; Bordy, J.M.; Barthe, J.

    2009-01-01

    This paper presents several R and D axes in absorbed close metrology to meet the needs resulting from the technical evolutions of external beam radiotherapy. The facilities in operation in France have considerably evolved under the impulse of the plan Cancer launched in 2003: replacements and increase of the number of accelerators, substitution of accelerators for telecobalt almost completed and acquisition of innovative facilities for tomo-therapy and stereotaxy. The increasing versatility of facilities makes possible the rapid evolution of treatment modalities, allowing to better delimit irradiation to tumoral tissues and spare surrounding healthy tissues and organs at risk. This leads to a better treatment efficacy through dose escalation. National metrology laboratories must offer responses adapted to the new need, i.e. not restrict themselves to the establishment of references under conventional conditions defined at international level, contribute to the improvement of uncertainties at all levels of reference transfer to practitioners: primary measurements under conditions as close as possible to those of treatment, characterization of transfer and treatment control dosimeters., metrological validation of treatment planning tools... Those axes have been identified as priorities for the next years in ionizing radiation metrology at the European level and included in the European. Metrology Research Programme. A project dealing with some of those topics has been selected in the frame of the Eranet+ Call EMRP 2007 and is now starting. The LNE-LAM is strongly engaged in it. (authors)

  10. 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

  11. Reconstruction of Absorbed Doses to Fibroglandular Tissue of the Breast of Women undergoing Mammography (1960 to the Present)

    Science.gov (United States)

    Thierry-Chef, Isabelle; Simon, Steven L.; Weinstock, Robert M.; Kwon, Deukwoo; Linet, Martha S.

    2013-01-01

    The assessment of potential benefits versus harms from mammographic examinations as described in the controversial breast cancer screening recommendations of the U.S. Preventive Task Force included limited consideration of absorbed dose to the fibroglandular tissue of the breast (glandular tissue dose), the tissue at risk for breast cancer. Epidemiological studies on cancer risks associated with diagnostic radiological examinations often lack accurate information on glandular tissue dose, and there is a clear need for better estimates of these doses. Our objective was to develop a quantitative summary of glandular tissue doses from mammography by considering sources of variation over time in key parameters including imaging protocols, x-ray target materials, voltage, filtration, incident air kerma, compressed breast thickness, and breast composition. We estimated the minimum, maximum, and mean values for glandular tissue dose for populations of exposed women within 5-year periods from 1960 to the present, with the minimum to maximum range likely including 90% to 95% of the entirety of the dose range from mammography in North America and Europe. Glandular tissue dose from a single view in mammography is presently about 2 mGy, about one-sixth the dose in the 1960s. The ratio of our estimates of maximum to minimum glandular tissue doses for average-size breasts was about 100 in the 1960s compared to a ratio of about 5 in recent years. Findings from our analysis provide quantitative information on glandular tissue doses from mammographic examinations which can be used in epidemiologic studies of breast cancer. PMID:21988547

  12. Estimation of yttrium-90 Zevalin tumor-absorbed dose in ocular adnexal lymphoma using quantitative indium-111 Zevalin radionuclide imaging.

    Science.gov (United States)

    Erwin, William D; Esmaeli, Bita

    2009-09-01

    The purpose of this investigation was to estimate radiation-absorbed dose in orbital tumors from yttrium-90 ibritumomab tiuxetan (Zevalin) radioimmunotherapy of ocular adnexal lymphoma. Three patients participating in a prospective research protocol involving treatment of ocular adnexal lymphoma with yttrium-90 Zevalin consented to quantitative radionuclide imaging to estimate tumor radiation-absorbed doses. Each patient received 185 MBq of indium-111 Zevalin, followed by serial planar whole-body scanning, to derive an activity versus time curve for the tumor. Single photon emission computed tomography (SPECT) and computed tomography (CT) imaging, including a calibration source, were performed at 24 h on a SPECT/CT scanner, to obtain a SPECT estimate of the radioactivity (in megabequerels) in the tumor and correct the planar curve, as well as estimate the tumor mass (M) from CT. The curve was then converted to that for yttrium-90 at the prescribed activity, and absorbed dose estimated from the area under the curve multiplied by the Medical Internal Radiation Dose S value (Gy per MBq-h) for a sphere of mass M. A right orbital tumor in one patient was visualized in both the planar and SPECT/CT images, with an estimated absorbed dose of 3.57 Gy. Tumor uptake in the other two patients was not visualized. The radiation dose to the orbit and ocular structures during radioimmunotherapy of ocular adnexal lymphoma is well below the threshold for significant radiation-induced ocular toxicity and about 10 times lower than that delivered during external beam radiotherapy.

  13. 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

  14. Absorbed and effective dose from newly developed cone beam computed tomography in Korea

    International Nuclear Information System (INIS)

    Lee, Jong Nyeong; Han, Won Jeong; Kim, Eun Kyung

    2007-01-01

    Cone beam computed tomography (CBCT) provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology. The purpose of this study was to evaluate the absolved and effective doses of Implagraphy and VCT (Vatech Co., Hwasung, Korea) and compare them with those of panoramic radiography. Thermoluminescent dosimeter (TLD) chips were placed at 27 sites throughout the layers of Female ART Head and Neck Phantom for dosimetry. Implagraphy, VCT units, and Planmeca Proline XC panoramic unit were used for radiation exposure. Radiation weighted doses and effective doses were measured and calculated using 1990 and 2005 ICRP tissue weighting factors. Effective doses in Sv (ICRP 2005, ICRP 1990) were 90.19, 61.62 for Implagraphy at maxillay molar area, 123.20, 90.02 for Implagraphy at mandibular molar area, 183.55, 139.26 for VCT and 40.92, 27.16 for panoramic radiography. Effective doses for VCT and Implagraphy were only about 2.2 to 4.5 times greater than those for panoramic radiography. VCT and Implagraphy, CBCT machines recently developed in Korea, showed moderately low effective doses

  15. Absorbed and effective dose from newly developed cone beam computed tomography in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Nyeong; Han, Won Jeong; Kim, Eun Kyung [Dankook Univ. School of Dentistry, Seoul (Korea, Republic of)

    2007-06-15

    Cone beam computed tomography (CBCT) provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology. The purpose of this study was to evaluate the absolved and effective doses of Implagraphy and VCT (Vatech Co., Hwasung, Korea) and compare them with those of panoramic radiography. Thermoluminescent dosimeter (TLD) chips were placed at 27 sites throughout the layers of Female ART Head and Neck Phantom for dosimetry. Implagraphy, VCT units, and Planmeca Proline XC panoramic unit were used for radiation exposure. Radiation weighted doses and effective doses were measured and calculated using 1990 and 2005 ICRP tissue weighting factors. Effective doses in Sv (ICRP 2005, ICRP 1990) were 90.19, 61.62 for Implagraphy at maxillay molar area, 123.20, 90.02 for Implagraphy at mandibular molar area, 183.55, 139.26 for VCT and 40.92, 27.16 for panoramic radiography. Effective doses for VCT and Implagraphy were only about 2.2 to 4.5 times greater than those for panoramic radiography. VCT and Implagraphy, CBCT machines recently developed in Korea, showed moderately low effective doses.

  16. Analysis of thyroid absorbed dose in cervical CT scan with the use of bismuth shielding

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Fernanda S.; Gómez, Álvaro M.L.; Mourão, Arnaldo P., E-mail: fernanda.stephaniebh@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Santana, Priscila C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Anatomia e Imagem

    2017-07-01

    The Computed Tomography (CT) has become an important tool to diagnose cancer and to obtain additional information for different clinical questions. Today, it is a very fast, painless and noninvasive test that can be performed high quality images. However, CT scan usually requires a higher radiation exposure dose than a conventional radiography examination. The aim of this study is to determine the dose variation deposited in thyroid and in nearby radiosensitive organs, such as: lenses, pharynx, hypophysis, salivary gland and spinal cord with and without the use of bismuth shielded. A cervical CT scan was performed on anthropomorphic male phantom model Alderson Rando, from the occipital to the first thoracic vertebra, using a GE scanner, Discovery model with 64 channels. Dose measurements have been performed by using radiochromic film strips to register the individual doses in the organs of interest. After the phantom cervical CT scan the radiochromic film strips were processed for obtaining digital images. Digital images were worked to obtain the dose variation profiles for each film. With the data obtained, it was found the organ dose variation. The results show that the thyroid received the highest dose, 40.9 mGy, in the phantom, according to the incidence of the primary X-ray beam. (author)

  17. Estimate of the absorbed dose in the mouse organs and tissues after tritium administration

    International Nuclear Information System (INIS)

    Saito, Masahiro

    2000-01-01

    Chronic and accidental release of tritium from future fusion facilities may cause some extent of hazardous effect to the public health. Various experiments using small animals such as mice have been performed to mimic the dose accumulation due to tritium intake by the human body. An difficulty in such animal experiments using small animals is that it is rather difficult to administer tritium orally and estimate the dose to small organs or tissues. In the course of our study, a simple method to administer THO and T-labeled amino acids orally to the mouse was dictated and dose accumulation in various organs and tissues was determined. The tritium retention in the bone marrow was also determined using the micro-centrifuge method. Throughout our experiment, colony-bred DDY mice were used. The 8-10 week old male mice were orally and intraperitoneally administered THO water or T-amino acids mixture solution. For the purpose of oral administration, a 10 μl aliquot of T-containing saline solution was placed on the tongue of the mice using an automatic micropipette. At various times after tritium administration, the animals were sacrificed and the amount of tritium in various tissues and organs including bone marrow was examined. Dose accumulation pattern after THO intake and T-amino acids was compared between intraperitoneal injection and oral administration. The accumulated dose after oral administration of THO exhibited a tendency to be 10-20% higher than after intraperitoneal injection. The bone marrow dose after oral intake of THO was found to be lower than the doses to urine, blood, liver and testis. In contrast, the blood dose gave a conservative estimate for the dose to the other tissues and organs. (author)

  18. Characterization of an absorbed dose standard in water through ionometric methods

    International Nuclear Information System (INIS)

    Vargas V, M.X.

    2003-01-01

    In this work the unit of absorbed dose at the Secondary Standard Dosimetry Laboratory (SSDL) of Mexico, is characterized by means of the development of a primary standard of absorbed dose to water, D agua . The main purpose is to diminish the uncertainty in the service of dosimetric calibration of ionization chambers (employed in radiotherapy of extemal beams) that offers this laboratory. This thesis is composed of seven chapters: In Chapter 1 the position and justification of the problem is described, as well as the general and specific objectives. In Chapter 2, a presentation of the main quantities and units used in dosimetry is made, in accordance with the recommendations of the International Commission on Radiation Units and Measurements (ICRU) that establish the necessity to have a coherent system with the international system of units and dosimetric quantities. The concepts of equilibrium and transient equilibrium of charged particles (TCPE) are also presented, which are used later in the quantitative determination of D agua . Finally, since the proposed standard of D agua is of ionometric type, an explanation of the Bragg-Gray and Spencer-Attix cavity theories is made. These theories are the foundation of this type of standards. On the other hand, to guarantee the complete validity of the conditions demanded by these theories it is necessary to introduce correction factors. These factors are determined in Chapters 5 and 6. Since for the calculation of the correction factors Monte Carlo (MC) method is used in an important way, in Chapter 3 the fundamental concepts of this method are presented; in particular the principles of the code MCNP4C [Briesmeister 2000] are detailed, making emphasis on the basis of electron transport and variance reduction techniques used in this thesis. Because a phenomenological approach is carried out in the development of the standard of D agua , in Chapter 4 the characteristics of the Picker C/9 unit, the ionization chamber type

  19. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Cheon, Geum Seong; Kim, Chang Uk; Kim, Hoi Nam; Heo, Gyeong Hun; Song, Jin Ho; Hong, Joo Yeong [Dept. of Radiation Oncology, Catholic University Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Jeong, Jae Yong [Dept. of Radiation Oncology, Inje University Sanggye Paik Hospital, Seoul (Korea, Republic of)

    2010-09-15

    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

  1. Monte Carlo calculations and measurements of absorbed dose per monitor unit for the treatment of uveal melanoma with proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Nicholas; Newhauser, Wayne D; Titt, Uwe; Starkschall, George [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); Gombos, Dan [Section of Ophthalmology, Department of Head and Neck Surgery MDACC Unit 441 (United States); Coombes, Kevin [Graduate School of Biomedical Sciences, University of Texas Health Science Center, 6767 Bertner Avenue, Houston, TX 77030 (United States)], E-mail: kochn@musc.edu

    2008-03-21

    The treatment of uveal melanoma with proton radiotherapy has provided excellent clinical outcomes. However, contemporary treatment planning systems use simplistic dose algorithms that limit the accuracy of relative dose distributions. Further, absolute predictions of absorbed dose per monitor unit are not yet available in these systems. The purpose of this study was to determine if Monte Carlo methods could predict dose per monitor unit (D/MU) value at the center of a proton spread-out Bragg peak (SOBP) to within 1% on measured values for a variety of treatment fields relevant to ocular proton therapy. The MCNPX Monte Carlo transport code, in combination with realistic models for the ocular beam delivery apparatus and a water phantom, was used to calculate dose distributions and D/MU values, which were verified by the measurements. Measured proton beam data included central-axis depth dose profiles, relative cross-field profiles and absolute D/MU measurements under several combinations of beam penetration ranges and range-modulation widths. The Monte Carlo method predicted D/MU values that agreed with measurement to within 1% and dose profiles that agreed with measurement to within 3% of peak dose or within 0.5 mm distance-to-agreement. Lastly, a demonstration of the clinical utility of this technique included calculations of dose distributions and D/MU values in a realistic model of the human eye. It is possible to predict D/MU values accurately for clinical relevant range-modulated proton beams for ocular therapy using the Monte Carlo method. It is thus feasible to use the Monte Carlo method as a routine absolute dose algorithm for ocular proton therapy.

  2. Proton absorbed dose distribution in human eye simulated by SRNA-2KG code

    International Nuclear Information System (INIS)

    Ilic, R. D.; Pavlovic, R.

    2004-01-01

    The model of Monte Carlo SRNA code is described together with some numerical experiments to show feasibility of this code to be used in proton therapy, especially for tree dimensional proton absorption dose calculation in human eye. (author) [sr

  3. 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

  4. Estimation of kidney depth effective renal plasmatic flux and absorbed dose, from a radio isotopic renogram

    International Nuclear Information System (INIS)

    Carvalho Pinto Ribela, M.T. de.

    1979-01-01

    A technique for the estimation of kidney depth is described. It is based on a comparison between the measurements obtained in a radioisotopic renogram carried out for two specific energies and the same measurements made with a phanto-kidney at different depths. Experiments performed with kidney and abdomen phantoms provide calibration curves which are obtained by plotting the photopeak to scatter ratio for 131 I pulse height spectrum against depth. Through this technique it is possible to obtain the Hippuran- 131 I kidney uptake with external measurements only. In fact it introduces a correction in the measurements for the depth itself and for the attenuation and scattering effects due to the tissues interposed between the kidney and the detector. When the two kidneys are not equidistant from the detector, their respective renograms are different and it is therefore very important to introduce a correction to the measurements according to the organ depth in order to obtain the exact information on Hippuran partition between the kidneys. The significative influence of the extrarenal activity is analyzed in the renogram by monitoring the praecordial region after 131 I-human serum albumin injection and establishing a calibration factor relating the radioactivity level of this area to that present in each kidney area. It is shown that it is possible to obtain the values for the clearance of each kidney from the renogram once the alteration in efficiency due to the organ depth and to non-renal tissue interference in the renal area is considered. This way, values for the effective renal plasma flow were obtained, which are comparable to those obtained with other techniques, estimating the total flow of the kidneys. Finally the mean absorbed dose of the kidneys in a renography is also estimated. (Author) [pt

  5. Determination of absorbed dose calibration factors for therapy level electron beam ionization chambers.

    Science.gov (United States)

    McEwen, M R; Williams, A J; DuSautoy, A R

    2001-03-01

    Over several years the National Physical Laboratory (NPL) has been developing an absorbed dose calibration service for electron beam radiotherapy. To test this service, a number of trial calibrations of therapy level electron beam ionization chambers have been carried out during the last 3 years. These trials involved 17 UK radiotherapy centres supplying a total of 46 chambers of the NACP, Markus, Roos and Farmer types. Calibration factors were derived from the primary standard calorimeter at seven energies in the range 4 to 19 MeV with an estimated uncertainty of +/-1.5% at the 95% confidence level. Investigations were also carried out into chamber perturbation, polarity effects, ion recombination and repeatability of the calibration process. The instruments were returned to the radiotherapy centres for measurements to be carried out comparing the NPL direct calibration with the 1996 IPEMB air kerma based Code of Practice. It was found that, in general, all chambers of a particular type showed the same energy response. However, it was found that polarity and recombination corrections were quite variable for Markus chambers-differences in the polarity correction of up to 1% were seen. Perturbation corrections were obtained and were found to agree well with the standard data used in the IPEMB Code. The results of the comparison between the NPL calibration and IPEMB Code show agreement between the two methods at the +/-1% level for the NACP and Farmer chambers, but there is a significant difference for the Markus chambers of around 2%. This difference between chamber types is most likely to be due to the design of the Markus chamber.

  6. 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

  7. 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

  8. 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.

  9. COMPARISON BETWEEN ABSORBED DOSES IN TARGET ORGANS IN PANORAMIC RADIOGRAPHY, USING SINGLE EMULSION AND DOUBLE EMULSION FILMS

    Directory of Open Access Journals (Sweden)

    A. R. Talaeipour

    2007-07-01

    Full Text Available "nThe use of panoramic radiography, due to its numerous advantages, is increasing. Radiographic films used in this technique are of double emulsion (DE type which are used with intensifying screens. Single emulsion (SE films can also be used. The purpose of this study was to determine the exposure parameters to achieve an appropriate optical density in these two types of films, and to estimate under such parameters, radiation doses to mandibular bone marrow (MBM, thyroid gland and parotid gland. This study was performed through a tissue equivalent phantom. First, with various tube voltage and tube current, 128 radiographs were taken of phantom with these two types of films. After examining the optical densities, the exposure parameters under which both films have the same density, were determined. Then, phantom again was exposed and MBM, thyroid gland and parotid gland absorbed doses were measured, using TLDs. It was demonstrated that: 1 SE films, in order to provide appropriate optical density, require two times radiation in comparison with double emulsion film; 2 using SE films increases MBM dose, up to 2-2.5 times, thyroid gland dose up to 1.7-2 times and parotid gland dose up to 1.3 times, in comparison with DE films; 3 in DE films, under lower exposure parameters and desirable processing, MBM dose up to 3.5 times, thyroid gland dose up to 1.5 times and parotid gland dose up to 2.5 times will increase. Considering that the risk of radiation induced cancers increases with repeated radiation doses, using SE films is not recommended.

  10. 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

  11. Location of radiosensitive organs, measurement of absorbed dose to radiosensitive organs and use of bismuth shields in paediatric anthropomorphic phantoms

    International Nuclear Information System (INIS)

    Inkoom, S.

    2014-08-01

    thyroid organ dose was reduced to 46% (10-y-old). The combined use of single shield and AEC reduced the thyroid surface dose to a maximum of 70% (5-y-old); whilst the thyroid organ dose was reduced to 62% (10-y-old). The use of double shields and AEC activation further reduced the surface / organ dose to 76% / 65% (5-y-old). The maximum dose to the eye lenses due to neck CT was 7.0 mGy / 6.2 mGy (10-y-old) for FTC / AEC. The maximum breast dose attributable to neck CT was 0.6 mGy for 5-, and 10-y-old phantoms for all protocols. For thorax CT scans, the use of AEC induced a significant increase in the thyroid organ dose by a maximum value of 70% (1-y-old), and thyroid surface dose by 70% (newborn), and mean breast surface dose by 69% (newborn). The maximum increase of the effective dose as a result of application of AEC was 54% (newborn). In conclusion, the production of charts of radiosensitive organs inside paediatric anthropomorphic phantoms for dosimetric purposes was feasible. In-plane bismuth thyroid shielding decreases radiation dose in MDCT with/without deteriorating image quality. AEC was more effective in thyroid dose reduction than in-plane bismuth shields (head and neck CT, neck CT). AEC increased the absorbed dose to both the thyroid and the breast, as well as the effective dose in thorax CT. Thus, AEC should be abandoned as a dose optimisation tool during thoracic MDCT, especially in neonates, infants and children younger than 10-years-old. Placement of the spacer between shield and surface had no significant impact on the measured doses, but significantly decreased the image noise. (au)

  12. Absorbed Internal Dose Conversion Coefficients for Domestic Reference Animals and Plant

    International Nuclear Information System (INIS)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho

    2010-01-01

    This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ( 3 H, 7 Be, 14 C, 40 K, 51 Cr, 54 Mn, 59 Fe, 58 Co, 60 Co, 65 Zn, 90 Sr, '9 5 Zr, 95 Nb, 99 Tc, 106 Ru, 129 I, 131 I, 136 Cs, 137 Cs, 140 Ba, 140 La, 144 Ce, 238 U, 239 Pu, 240 Pu) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (μGyd -1 per Bqkg -1 ) ranged from 10 -6 to 10 -2 according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as 238 U, 239 Pu, and 240 Pu, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of 239 Pu, 240 Pu, 238 U, 14 C, 3 H and 99 Tc were independent of the organism

  13. Absorbed Internal Dose Conversion Coefficients for Domestic Reference Animals and Plant

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-02-15

    This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ({sup 3}H, {sup 7}Be, {sup 14}C, {sup 40}K, {sup 51}Cr, {sup 54}Mn, {sup 59}Fe, {sup 58}Co, {sup 60}Co, {sup 65}Zn, {sup 90}Sr, '9{sup 5}Zr, {sup 95}Nb, {sup 99}Tc, {sup 106}Ru, {sup 129}I, {sup 131}I, {sup 136}Cs, {sup 137}Cs, {sup 140}Ba, {sup 140}La, {sup 144}Ce, {sup 238}U, {sup 239}Pu, {sup 240}Pu) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (muGyd{sup -1} per Bqkg{sup -1}) ranged from 10{sup -6} to 10{sup -2} according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as {sup 238}U, {sup 239}Pu, and {sup 240}Pu, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of {sup 239}Pu, {sup 240}Pu, {sup 238}U, {sup 14}C, {sup 3}H and {sup 99}Tc were independent of the organism

  14. Radiation absorbed doses in the event of balloon rupture (BR) during endovascular brachytherapy (EB) using 188Re-perrhenate

    International Nuclear Information System (INIS)

    Angelides, S.; Hetherington, E.; Karolis, C.; Walker, B.; Jackson, T.; Knittel, T.; Friend, C.; Pitney, M.; Jepson, N.; Milross, C.; Lonergan, D.

    2000-01-01

    Full text: endovascular brachytherapy (EB) using liquid or solid radiation sources, is an effective emerging therapy for coronary artery disease. Liquid sources provide uniform radiation dose to the vessel wall. However the radiation burden in the unlikely event of BR is not insignificant. The aims of this study were to determine i) absorbed dose for various 188 Re radiopharmaceuticals in the event of BR, and ii) effects of thyroid uptake blocking agent, Lugol's iodine (Ll) and/or bladder catheterisation (BC). Dose calculations were based on MIRDOSE 3.1 with dynamic bladder model and MIRD Dose Estimate Report No.8 for 99 Tc m -pertechnetate, which has similar biokinetic properties to 188 Re-perrhenate. Normal renal function and a bladder voiding interval of 4.8h (1 minute with catheter) were assumed. BR was simulated ex-vivo by puncturing a Solaris angioplasty balloon filled with normal saline at 4 atm. LI, MAG3 and DTPA substantially reduces the radiation dose following BR, particularly to the thyroid, and BC reduces the bladder wall dose. Only the contents of the balloon leaked; 0.4 ml of the total volume of 1.8ml. As binding of 188 Re to ligands is cumbersome, we opted to use LI. Twenty five patients with in-stent re-stenosis have been treated using 188 Re-perrhenate (8 GBq/ml), with no BR. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  15. Estimation of absorbed dose by newborn patients subjected to chest radiographs

    International Nuclear Information System (INIS)

    Bunick, Ana P.; Schelin, Hugo R.; Denyak, Valeriy

    2016-01-01

    The aim of this study is to present an estimate of the effective dose received by newborn patients hospitalized in NICU and subjected to X-ray examinations of the chest in the AP projection. Initially, were followed examinations chest X-rays performed on newborn patients and subsequently, simulated in a newborn simulator object. The ESAK values obtained by TLDs were used to calculate the effective dose obtained at each examination by Caldose X software. The estimated values for the effective dose in the simulated exams in this study range from 2,3μSv the 10,7μSv. The results achieved are, generally, inferior to those reported for similar previous studies. (author)

  16. Assessment of Absorbed Dose in Persons close to the Patients during 192Ir brachytherapy for Cervical Cancer

    International Nuclear Information System (INIS)

    Jung, Joo Young; Kang, Se Sik

    2010-01-01

    According to the 2007 Annual Report of the National Cancer Registry, cervical cancer showed an occurring frequency of 7th in female cancers and 4rd in females with an age of 35-64 years. Both radiotherapy and chemotherapy are mainly used for the treatment of cervical cancer. In case of radiotherapy, brachytherapy using radioisotopes in conjunction with external-beam radiation therapy (EBRT) using a linear accelerator is used in most cases to improve the outcome of cancer treatment. Brachytherapy, one of the cervical cancer radiotherapies, is a method that can minimize the damage of normal tissues restricting absorbed dose to uterus. It is, however, necessary to conduct a quantitative assessment on brachytherapy because it may cause radiation exposure to medical care providers during the radiotherapy. Therefore, the study provides the basic research data regarding brachytherapy for cervical cancer, estimating the absorbed dose in persons close to the patients using a mathematical phantom during 192Ir brachytherapy for cervical cancer

  17. Thyroid dose of I-131 absorbed by the internal organs of a pregnant woman

    International Nuclear Information System (INIS)

    Arcos P, A.; Manzanares A, E.; Vega C, H.R.; Leon, C.L. de

    2007-01-01

    The use of nuclear techniques, for diagnosis or treatment, generates stress in the patient and its relatives. During the pregnancy some sufferings related with the thyroid gland can be presented. If the patient is pregnant, OEP or NOEP, the stress comes from the fear to that the product can it turns affected. The dose is calculated that the Iodine 131, captured by the thyroid of a woman with three months of pregnancy, it deposits in the brain, stomach, heart, kidneys, liver, lungs, ovaries, pancreas, thymus, spleen and in the uterus. The thymus is the organ that receives the biggest dose. (Author)

  18. Effects of differents gamma radiation doses absorbed for postharvest tomato fruits

    International Nuclear Information System (INIS)

    Silva Abreu, Toneypson da; Jesus, Edgar F.O. de; Soares, Antonio G.

    1997-01-01

    Postharvest tomato fuits Santa Cruz were submitted to prestorage gamma irradiation treatment with different doses range zero (unirradiated fruits) to 1000 Gy. The aim of this study is to evaluate the postharvest quality parameters: Hunter colour values for light transmittance analysis, pH, total titratable acidity, total soluble solids, maximum firmness and maturity stage. The fruits were stored under (25±1) 0 C with (93±3) relative humidity. The results obtained from the different irradiated treatments showed 600 Gy as the best dose to increase the shelf-life of tomato fruits and to decay its ripening. (author). 5 refs., 12 figs., 1 tab

  19. Interlaboratory comparisons in kerma in the air measures and absorbed dose in water using 60Co beams in radiotherapy

    International Nuclear Information System (INIS)

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

    2013-01-01

    In order to ensure that the measures of a quantity have high reliability and traceability interlaboratory comparisons are performed. The LNMRI has participated in several these interlaboratory comparisons. In the period 2000-2013 the LNMRI participated in 5 interlaboratory comparisons for measurement of kerma coefficients in the air and absorbed dose coefficients in the water. The results of interlaboratory comparisons indicate that the measures taken are appropriate to the LNMRI regarding the accuracy and precision measuring of these quantities

  20. Difference in average absorbed doses for dogs irradiated with 60Co γ-rays at various angles

    International Nuclear Information System (INIS)

    Wang Yuexing; Ma Xiaolin; Lu Yongjie

    1987-01-01

    The experiments including irradiation at 14 angles have been made in tissue-equivalent dog phantoms. The formula for calculating the average absorbed dose D-bar with relation to whole-body irradiation was estabilished. The D-bar depends on d, L, θ, ψ, R and X-bar, where, d signifies the width between shoulders of the irradiated dog, L the length of the dog from os parietale to os ischii,, θ, φ the angles at which the dog is irradiated, R the distance from radiation source to the centre of gravity of the dog, and X-bar the average exposure dose in air at the space where the dog's trunk is irradiated. The average doses D-bar measured by thermoluminescence dosemeter(TLD) and ionization chamber were in good agreement with the calculated data using the formula. the results of the experiments show that the D-bar correlates with θ and φ closely

  1. Dose absorbed in adults and children thyroid due to the I123 using the dosimetry MIRD and Marinelli

    International Nuclear Information System (INIS)

    Vasquez, M.; Castillo, C.; Cabrera, C.; Sarachaga, R.; Castaneda, J.; Diaz, E.

    2014-08-01

    Using the dosimetry MIRD, and representation Cristy-Eckerman in the thyroid gland and organs of their bio-kinetics when I 123 (Iodine) is used, the study demonstrates that the absorbed dose by the gland of an adult, children, and newly born, is their auto-dose, independent of the compartments number of their bio-kinetics. The dosimetric contributions of the organs of their bio-kinetics are insignificant. Their results are not significantly different to those obtained by the formalism MARINELLI (auto-dose) when it uses a sphere like glandular representation. In consequence, the kinetic model corresponding to the glandular representation decreases to a compartment, where the gland can also be represented like a sphere. (Author)

  2. On the suitability of ultrathin detectors for absorbed dose assessment in the presence of high-density heterogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, M., E-mail: marta.bueno@upc.edu; Duch, M. A. [Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); Carrasco, P.; Jornet, N. [Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i de Sant Pau, 08025 Barcelona (Spain); Muñoz-Montplet, C. [Servei de Física Mèdica i Protecció Radiològica, Institut Català d’Oncologia—Girona, 17007 Girona (Spain)

    2014-08-15

    Purpose: The aim of this study was to evaluate the suitability of several detectors for the determination of absorbed dose in bone. Methods: Three types of ultrathin LiF-based thermoluminescent dosimeters (TLDs)—two LiF:Mg,Cu,P-based (MCP-Ns and TLD-2000F) and a{sup 7}Li-enriched LiF:Mg,Ti-based (MTS-7s)—as well as EBT2 Gafchromic films were used to measure percentage depth-dose distributions (PDDs) in a water-equivalent phantom with a bone-equivalent heterogeneity for 6 and 18 MV and a set of field sizes ranging from 5×5 cm{sup 2} to 20×20 cm{sup 2}. MCP-Ns, TLD-2000F, MTS-7s, and EBT2 have active layers of 50, 20, 50, and 30 μm, respectively. Monte Carlo (MC) dose calculations (PENELOPE code) were used as the reference and helped to understand the experimental results and to evaluate the potential perturbation of the fluence in bone caused by the presence of the detectors. The energy dependence and linearity of the TLDs’ response was evaluated. Results: TLDs exhibited flat energy responses (within 2.5%) and linearity with dose (within 1.1%) within the range of interest for the selected beams. The results revealed that all considered detectors perturb the electron fluence with respect to the energy inside the bone-equivalent material. MCP-Ns and MTS-7s underestimated the absorbed dose in bone by 4%–5%. EBT2 exhibited comparable accuracy to MTS-7s and MCP-Ns. TLD-2000F was able to determine the dose within 2% accuracy. No dependence on the beam energy or field size was observed. The MC calculations showed that a50 μm thick detector can provide reliable dose estimations in bone regardless of whether it is made of LiF, water or EBT’s active layer material. Conclusions: TLD-2000F was found to be suitable for providing reliable absorbed dose measurements in the presence of bone for high-energy x-ray beams.

  3. A volume-equivalent spherical necrosis-tumor-normal liver model for estimating absorbed dose in yttrium-90 microsphere therapy.

    Science.gov (United States)

    Wu, Chin-Hui; Liao, Yi-Jen; Lin, Tzung-Yi; Chen, Yu-Cheng; Sun, Shung-Shung; Liu, Yen-Wan Hsueh; Hsu, Shih-Ming

    2016-11-01

    Primary hepatocellular carcinoma and metastatic liver tumors are highly malignant tumors in Asia. The incidence of fatal liver cancer is also increasing in the United States. The aim of this study was to establish a spherical tumor model and determine its accuracy in predicting the absorbed dose in yttrium-90 (Y-90) microsphere therapy for liver cancer. Liver morphology can be approximated by a spherical model comprising three concentric regions representing necrotic, tumor, and normal liver tissues. The volumes of these three regions represent those in the actual liver. A spherical tumor model was proposed to calculate the absorbed fractions in the spherical tumor, necrotic, and normal tissue regions. The THORplan treatment planning system and Monte Carlo N-particle extended codes were used for this spherical tumor model. Using the volume-equivalent method, a spherical tumor model was created to calculate the total absorbed fraction [under different tumor-to-healthy-liver ratios (TLRs)]. The patient-specific model (THORplan) results were used to verify the spherical tumor model results. The results for both the Y-90 spectrum and the Y-90 mean energy indicated that the absorbed fraction was a function of the tumor radius and mass. The absorbed fraction increased with tumor radius. The total absorbed fractions calculated using the spherical tumor model for necrotic, liver tumor, and normal liver tissues were in good agreement with the THORplan results, with differences of less than 3% for TLRs of 2-5. The results for the effect of TLR indicate that for the same tumor configuration, the total absorbed fraction decreased with increasing TLR; for the same shell tumor thickness and TLR, the total absorbed fraction was approximately constant; and for tumors with the same radius, the total fraction absorbed by the tumor increased with the shell thickness. The results from spherical tumor models with different tumor-to-healthy-liver ratios were highly consistent with the

  4. A fibre optic scintillator dosemeter for absorbed dose measurements of low-energy X-ray-emitting brachytherapy sources

    International Nuclear Information System (INIS)

    Sliski, A.; Soares, C.; Mitch, M. G.

    2006-01-01

    A newly developed dosemeter using a 0.5 mm diameter x 0.5 mm thick cylindrical plastic scintillator coupled to the end of a fibre optic cable is capable of measuring the absorbed dose rate in water around low-activity, low-energy X-ray emitters typically used in prostate brachytherapy. Recent tests of this dosemeter showed that it is possible to measure the dose rate as a function of distance in water from 2 to 30 mm of a 103 Pd source of air-kerma strength 3.4 U (1 U = 1 μGy m 2 h -1 ), or 97 MBq (2.6 mCi) apparent activity, with good signal-to-noise ratio. The signal-to-noise ratio is only dependent on the integration time and background subtraction. The detector volume is enclosed in optically opaque, nearly water-equivalent materials so that there is no polar response other than that due to the shape of the scintillator volume chosen, in this case cylindrical. The absorbed dose rate very close to commercial brachytherapy sources can be mapped in an automated water phantom, providing a 3-D dose distribution with sub-millimeter spatial resolution. The sensitive volume of the detector is 0.5 mm from the end of the optically opaque waterproof housing, enabling measurements at very close distances to sources. The sensitive detector electronics allow the measurement of very low dose rates, as exist at centimeter distances from these sources. The detector is also applicable to mapping dose distributions from more complex source geometries such as eye applicators for treating macular degeneration. (authors)

  5. Modeling the absorbed dose to the common carotid arteries following radioiodine treatment of benign thyroid disease

    DEFF Research Database (Denmark)

    la Cour, Jeppe Lerche; Hedemann-Jensen, Per; Søgaard-Hansen, Jens

    2013-01-01

    in the western countries are treated each year with RAI for benign thyroid disorders (about 140,000 a year in the EU), stressing that it is of clinical importance to be aware of even rare radiation-induced side effects. In order to induce or accelerate atherosclerosis, the dose to the carotid arteries has...

  6. 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

    Tetrazolium salts as heterocyclic organic compounds are known to form highly coloured, water insoluble formazans by reduction, which can be utilized in radiation processing dosimetry. Radiochromic films containing nitro blue tetrazolium dissolved in a polymer matrix were found suitable for dose...

  7. Absorbed dose evaluation of Auger electron-emitting radionuclides: impact of input decay spectra on dose point kernels and S-values.

    Science.gov (United States)

    Falzone, Nadia; Lee, Boon Q; Fernández-Varea, José M; Kartsonaki, Christiana; Stuchbery, Andrew E; Kibédi, Tibor; Vallis, Katherine A

    2017-03-21

    The aim of this study was to investigate the impact of decay data provided by the newly developed stochastic atomic relaxation model BrIccEmis on dose point kernels (DPKs - radial dose distribution around a unit point source) and S-values (absorbed dose per unit cumulated activity) of 14 Auger electron (AE) emitting radionuclides, namely 67 Ga, 80m Br, 89 Zr, 90 Nb, 99m Tc, 111 In, 117m Sn, 119 Sb, 123 I, 124 I, 125 I, 135 La, 195m Pt and 201 Tl. Radiation spectra were based on the nuclear decay data from the medical internal radiation dose (MIRD) RADTABS program and the BrIccEmis code, assuming both an isolated-atom and condensed-phase approach. DPKs were simulated with the PENELOPE Monte Carlo (MC) code using event-by-event electron and photon transport. S-values for concentric spherical cells of various sizes were derived from these DPKs using appropriate geometric reduction factors. The number of Auger and Coster-Kronig (CK) electrons and x-ray photons released per nuclear decay (yield) from MIRD-RADTABS were consistently higher than those calculated using BrIccEmis. DPKs for the electron spectra from BrIccEmis were considerably different from MIRD-RADTABS in the first few hundred nanometres from a point source where most of the Auger electrons are stopped. S-values were, however, not significantly impacted as the differences in DPKs in the sub-micrometre dimension were quickly diminished in larger dimensions. Overestimation in the total AE energy output by MIRD-RADTABS leads to higher predicted energy deposition by AE emitting radionuclides, especially in the immediate vicinity of the decaying radionuclides. This should be taken into account when MIRD-RADTABS data are used to simulate biological damage at nanoscale dimensions.

  8. Comparison of mathematical models for red marrow and blood absorbed dose estimation in the radioiodine treatment of advanced differentiated thyroid carcinoma.

    Science.gov (United States)

    Miranti, A; Giostra, A; Richetta, E; Gino, E; Pellerito, R E; Stasi, M

    2015-02-07

    Metastatic and recurrent differentiated thyroid carcinoma is preferably treated with (131)I, whose administered activity is limited by red marrow (RM) toxicity, originally correlated by Benua to a blood absorbed dose higher than 2 Gy. Afterward a variety of dosimetric approaches has been proposed. The aim of this work is to compare the results of the Benua formula with the ones of other three blood and RM absorbed dose formulae. Materials and methods have been borrowed by the dosimetric protocol of the Italian Internal Dosimetry group and adapted to the routine of our centre. Wilcoxon t-tests and percentage differences have been applied for comparison purposes. Results are significantly different (p < 0.05) from each other, with an average percentage difference between Benua versus other results of -22%. The dosimetric formula applied to determine blood or RM absorbed dose may contribute significantly to increase heterogeneity in absorbed dose and dose-response results. Standardization should be a major objective.

  9. Developing point of care and high-throughput biological assays for determining absorbed radiation dose

    International Nuclear Information System (INIS)

    Joiner, Michael C.; Thomas, Robert A.; Grever, William E.; Smolinski, Joseph M.; Divine, George W.; Konski, Andre A.; Auner, Gregory W.; Tucker, James D.

    2011-01-01

    Background and purpose: Systems are being developed to assess radiation exposure based on leukocyte mRNA levels obtained by finger-stick sampling. The goal is to provide accurate detection of dose exposures up to 10 Gy for up to 1 week following exposure. We previously showed that specific mRNA sequences increase expression within an hour of exposure, and some genes continue to show elevated expression for at least 24 h. Full duration and dose-dependence of this persistence remain to be determined. In the present study, real-time quantitative PCR (qPCR) was used to determine changes in gene expression. qPCR can rapidly analyze small blood samples and could be adopted into a field-portable instrument that provides a radiation dose readout within 30 min. Materials and methods: From previous microarray analysis of 21,000 genes expressed in human lymphoblastoid cells 4 h post-irradiation (0–4 Gy), 118 genes were selected for evaluation by qPCR of gene expression in the leukocytes of human blood irradiated in vitro with doses of 0–10 Gy from a Co-60 gamma source at a dose rate of 30 cGy/min. Results: Blood from 20 normal healthy human donors yielded many mRNA sequences that could be used for radiation dosimetry. We observed four genes with large and persistent responses following exposure: ASTN2, CDKN1A, GADD45A, and GDF15. Five genes were identified as reliably non-responsive and were suitable for use as endogenous controls: DPM1, ITFG1, MAP4, PGK1, and SLC25A36; of these, ITFG1 was used for the analyses presented here. A significant dose-responsive increase in expression occurred for CDKN1A that was >16-fold at 10 Gy and 3-fold at 0.5 Gy compared to pre-irradiation values. Conclusions: These data show large, selective increases in mRNA transcript levels that persist for at least 48 h after single exposures between 0.5 and 10 Gy. Stable, non-responsive mRNA sequences for use as endogenous controls were also identified. These results indicate that following further

  10. Evaluation of {sup 99}Mo/{sup 99m}Tc generator columns after irradiation with different absorbed doses

    Energy Technology Data Exchange (ETDEWEB)

    Fukumori, Neuza T.O.; Mengatti, Jair; Matsuda, Margareth M.N., E-mail: ntfukumo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNE-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    The {sup 99}Mo/{sup 99m}Tc generator is widely used in nuclear medicine and it consists of a glass column containing Teflon® strips and alumina in which {sup 99}Mo produced by {sup 235}U fission is adsorbed. The {sup 99}mTcO4- eluate shall meet the sterile and pyrogen free conditions for injectable radiopharmaceuticals as determined by the Good Manufacturing Practices. The purpose of this study was to evaluate the feasibility of using gamma radiation in the sterilization of the {sup 99}Mo/{sup 99m}Tc generator column and the influence on the elution efficiency. Alumina-containing columns were irradiated with 10, 15, 25 and 50 kGy absorbed doses. Alumina samples and control (non-irradiated) were submitted to X-ray diffraction and the combined use of scanning electron microscopy and elemental analysis. Teflon® samples were evaluated by thermogravimetry (TGA) and differential scanning calorimetry (DSC). X-ray diffractograms and micrographies with elemental analysis showed no significant changes in the crystalline structure of the alumina because it was stable α-Al{sub 2}O{sub 3}. TGA demonstrated that higher doses showed changes in lower temperatures and times than the control material. For DSC the higher the absorbed dose, the greater the polymer chain breakage and crosslinking in the material. The generator system without radioactivity was set up with the irradiated columns and the eluates demonstrated to be sterile and pyrogen free. The effects of different absorbed doses on the generator column, although some reported changes in the materials, demonstrated that the sterilization of the columns by irradiation with gamma rays as an alternative to wet heat sterilization is feasible from a technical and financial point of view. (author)

  11. 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.

  12. Comparison of the Absorbed Dose of Target Organs between Conventional and Digital Panoramic Radiography

    OpenAIRE

    Zohre Reyhani; Nadia Nil Avar; Mohamad Ali Moghadam

    2016-01-01

    The purpose of this study was to measure and compare target organ’s exposure by direct digital and conventional panoramic radiography. Dose measurements were carried out on a RANDO phantom, which TLDs were placed into 5 target area: thyroid gland, left and right submandibular and parotid salivary glands. Panoramic radiographs were taken with two conventional (CRANEX Tome, Soredex, Tusula Finland) and direct digital devices (CRANEX D, Soredex, Tusula Finland).In total, the phantom was ir...

  13. Simulations of absorbed dose on the phantom surface of MATROSHKA-R experiment at the ISS

    Czech Academy of Sciences Publication Activity Database

    Kolísková, Zlata; Sihver, L.; Ambrožová, Iva; Sato, T.; Spurný, František; Shurshakov, V. A.

    2012-01-01

    Roč. 49, č. 2 (2012), s. 230-236 ISSN 0273-1177 R&D Projects: GA ČR GA205/09/0171; GA AV ČR KJB100480901; GA ČR GD202/09/H086 Institutional research plan: CEZ:AV0Z10480505 Keywords : MATROSHKA-R * PHITS * Simulations * Space radiation * Dose estimation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.183, year: 2012

  14. The influence of calculated CT X-ray spectra on organ absorbed dose to a human phantom

    International Nuclear Information System (INIS)

    Ferreira, C.C.; Vieira, J.W.; Maia, A.F.

    2009-01-01

    We have evaluated the utilization of five X-ray spectra codes for Monte Carlo (MC) simulations of computed tomography (CT) examinations. Four codes (Xcomp5r, X-raytbc, X-rayb and m and Srs-78) are semi-empiricals and one is based on MC methods (EGSnrc/BEAM Monte Carlo code). The X-ray spectra calculated by the semi-empirical codes were compared with the X-ray spectrum calculated by the EGSnrc/BEAM MC code. The absorbed doses to each organ or tissue were also compared. The calculated doses, and its respective organs, for which occurs the greatest disagreement, as well as the calculated doses for the testes and red bone marrow (two important organs used for calculating effective dose) were presented. The results obtained in this work are in good agreement with those obtained by Ay [M.R. Ay, S. Sarkar, M. Shahriari, D. Sardari, H. Zaidi, Assessment of different computational models for generation of X-ray spectra in diagnostic radiology and mammography, Med. Phys. 32 (2005) 1660], mainly for the bremsstrahlung distribution. Also, it was noted that the total characteristic X-rays produced by the EGSnrc/BEAM MC code increases with the increase of voltage more intensely than with the Xcomp5r, X-raytbc and Srs-78 codes. Comparison between the absorbed dose to each organ or tissue showed that, for X-ray spectra with additional filtration, the code based on Tucker et al. is in agreement with EGSnrc/BEAM MC code. But, for X-ray spectra without additional filtration the code based on Tucker et al. model presented the strong disagreement with EGSnrc/BEAM MC code.

  15. The influence of calculated CT X-ray spectra on organ absorbed dose to a human phantom

    Science.gov (United States)

    Ferreira, C. C.; Vieira, J. W.; Maia, A. F.

    2009-10-01

    We have evaluated the utilization of five X-ray spectra codes for Monte Carlo (MC) simulations of computed tomography (CT) examinations. Four codes (Xcomp5r, X-raytbc, X-rayb&m and Srs-78) are semi-empiricals and one is based on MC methods (EGSnrc/BEAM Monte Carlo code). The X-ray spectra calculated by the semi-empirical codes were compared with the X-ray spectrum calculated by the EGSnrc/BEAM MC code. The absorbed doses to each organ or tissue were also compared. The calculated doses, and its respective organs, for which occurs the greatest disagreement, as well as the calculated doses for the testes and red bone marrow (two important organs used for calculating effective dose) were presented. The results obtained in this work are in good agreement with those obtained by Ay [M.R. Ay, S. Sarkar, M. Shahriari, D. Sardari, H. Zaidi, Assessment of different computational models for generation of X-ray spectra in diagnostic radiology and mammography, Med. Phys. 32 (2005) 1660], mainly for the bremsstrahlung distribution. Also, it was noted that the total characteristic X-rays produced by the EGSnrc/BEAM MC code increases with the increase of voltage more intensely than with the Xcomp5r, X-raytbc and Srs-78 codes. Comparison between the absorbed dose to each organ or tissue showed that, for X-ray spectra with additional filtration, the code based on Tucker et al. is in agreement with EGSnrc/BEAM MC code. But, for X-ray spectra without additional filtration the code based on Tucker et al. model presented the strong disagreement with EGSnrc/BEAM MC code.

  16. The generation of absorbed dose profiles of proton beam in water using Geant4 code

    International Nuclear Information System (INIS)

    Christovao, Marilia T.; Campos, Tarcisio Passos R. de

    2007-01-01

    The present article approaches simulations on the proton beam radiation therapy, using an application based on the code GEANT4, with Open GL as a visualization drive and JAS3 (Java Analysis Studio) analysis data tools systems, implementing the AIDA interfaces. The proton radiotherapy is adapted to treat cancer or other benign tumors that are close to sensitive structures, since it allows precise irradiation of the target with high doses, while the health tissues adjacent to vital organs and tissues are preserved, due to physical property of dose profile. GEANT4 is a toolkit for simulating the transport of particles through matter, in complex geometries. Taking advantage of the object-oriented project features, the user can adapt or extend the tool in all domain, due to the flexibility of the code, providing a subroutine's group for materials definition, geometries and particles properties in agreement with the user's needs to generate the Monte Carlo simulation. In this paper, the parameters of beam line used in the simulation possess adjustment elements, such as: the range shifter, composition and dimension; the beam line, energy, intensity, length, according with physic processes applied. The simulation result is the depth dose profiles on water, dependent on the various incident beam energy. Starting from those profiles, one can define appropriate conditions for proton radiotherapy in ocular region. (author)

  17. 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)

  18. Absorbed dose at subcellular level by Monte Carlo simulation for a {sup 99m}Tc-peptide with nuclear internalization

    Energy Technology Data Exchange (ETDEWEB)

    Rojas C, E. L.; Ferro F, G. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Santos C, C. L., E-mail: leticia.rojas@inin.gob.m [Universidad Autonoma del Estado de Mexico, Paseo Tollocan esquina Paseo Colon s/n, Toluca 50120, Estado de Mexico (Mexico)

    2010-10-15

    The utility of radiolabeled peptides for the early and specific diagnosis of cancer is being investigated around the world. Recent investigations have demonstrated the specificity of {sup 99m}Tc-bombesin conjugates to target breast and prostate cancer cells. The novel idea of adding the Tat (49-57) peptide to the radiopharmaceutical in order to penetrate the cell nucleus is a new proposal for therapy at cellular level. {sup 99m}Tc radionuclide produces Auger energy of 0.9 keV/decay and internal conversion electron energy of 15.4 keV/decay, which represent 11.4% of the total {sup 99m}Tc energy released per decay. It is expected that the dose delivered at specific microscopic levels in cancer cells induce a therapeutic effect. The aim of this research was to assess in vitro internalization kinetics in breast and prostate cancer cells of {sup 99m}Tc-Tat(49-57)-bombesin and to evaluate the radiation absorbed dose at subcellular level simulating the electron transport. The pen main program from the 2006 version of the Penelope code was used to simulate and calculate the absorbed dose by Auger and internal conversion electron contribution in the membrane, cytoplasm and nucleus of Pc-3 prostate cancer and MCF7 and MDA human breast cancer cell lines. Nuclear data were obtained from the 2002 BNM-LNHB {sup 99m}Tc decay scheme. The spatial distribution of the absorbed doses to the membrane, cytoplasm and nucleus were calculated using a geometric model built from real images of cancer cells. The elemental cell composition was taken from the literature. The biokinetic data were obtained evaluating total disintegrations in each subcellular compartment by integration of the time-activity curves acquired from experimental data. Results showed that 61, 63 and 46% of total disintegrations per cell-bound {sup 99m}Tc-Tat-Bn activity unit occurred in the nucleus of Pc-3, MCF7 and MDA-MB231 respectively. {sup 99m}Tc--Tat-Bn absorbed doses were 1.78, 5.76 and 2.59 Gy/Bq in the nucleus of

  19. Application of in vitro transmucosal permeability, dose number, and maximum absorbable dose for biopharmaceutics assessment during early drug development for intraoral delivery.

    Science.gov (United States)

    Yang, Zhen; Sotthivirat, Sutthilug; Wu, Yunhui; Lalloo, Anita; Nissley, Becky; Manser, Kimberly; Li, Hankun

    2016-04-30

    Intraoral (IO) administration is a unique route that takes advantage of transmucosal absorption in the oral cavity to deliver a drug substance locally or systemically. IO delivery can also enhance or enable oral administration, providing a better therapeutic benefit/safety risk profile for patient compliance. However, there are relatively few systematic biopharmaceutics assessments for IO delivery to date. Therefore, the goals of this study were to i) identify the most relevant in vitro permeability models as alternatives to porcine oral tissues (gold standard) for predicting human IO absorption and ii) establish guidelines for biopharmaceutics assessment during early drug development for IO delivery. Porcine kidney LLC-PK1 cells provided the strongest correlation of transmucosal permeability with porcine oral tissues followed by human Caco-2 cells. Furthermore, cultured human buccal tissues predicted high/low permeability classification and correlated well with porcine oral tissues, which are used for predicting clinical IO absorption. In the meantime, we introduced maximum absorbable dose and dose number in the oral cavity for IO delivery assessment as well as a decision tree to provide guidance for biopharmaceutics assessment during early drug development for IO delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Measurement and modeling of gamma-absorbed doses due to atmospheric releases from Los Alamos Meson Physics Facility

    International Nuclear Information System (INIS)

    Bowen, B.M.; Chen, A.I.; Olsen, W.A.; Van Etten, D.M.

    1985-01-01

    Short-term gamma-absorbed doses were measured by one high-pressure ionization chamber (HPIC) at an azimuth of 12 0 from the Los Alamos Meson Physics Facility (LAMPF) stack during the January 1 through February 8 operating cycle. Two HPICs were in the field during the September 8 through December 31 operating cycle, one north and the other north-northeast of the LAMPF stack, but they did not provide reliable data. Meteorological data were also measured at both East Gate and LAMPF. Airborne emission data were taken at the stack. Daily model predictions, based on the integration of modeled 15-min periods, were made for the first LAMPF operating cycle and were compared with the measured data. A comparison of the predicted and measured daily gamma doses due to LAMPF emissions is presented. There is very good correlation between measured and predicted values. During 39-day operating cycles, the model predicted an absorbed dose of 10.3 mrad compared with the 8.8 mrad that was measured, an overprediction of 17%

  1. Creation of ORNL NURBS-based phantoms: evaluation of the voxel effect on absorbed doses from radiopharmaceuticals.

    Science.gov (United States)

    Gardumi, Anna; Farah, Jad; Desbrée, Aurélie

    2013-03-01

    Doses from radiopharmaceuticals absorbed by organs can be assessed using Monte Carlo simulations and computational phantoms. Patient-based voxel phantoms improve the realism of organ topology but present unrealistic stair-stepped surfaces. The goal of this research was to study the voxel effect on the basis of creation and voxelisation of a series of non-uniform rational B-spline (NURBS) reference phantoms issued from the publication of the Oak Ridge National Laboratory (ORNL). Absorbed doses from various radiopharmaceuticals were calculated and compared with the values obtained for the corresponding analytical phantoms for models of an adult male and a 5-y-old child. Dose differences lower than 12.5 % were observed when the critical structure of the skin was excluded. Moreover, the highest differences were noted for small organs and walls. Finally, all NURBS phantoms of the ORNL series, their voxelised version and the corresponding Monte Carlo N-Particle eXtended input files were programmed and are available for further simulations.

  2. Study of the heterogeneity effects of lung in the evaluation of absorbed dose in radiotherapy

    International Nuclear Information System (INIS)

    Campos, Luciana Tourinho

    2006-02-01

    The main objective of radiotherapy is to deliver the highest possible dose to the tumour, in order to destroy it, reducing as much as possible the doses to healthy tissues adjacent to the target volume. Therefore, it is necessary to do a planning of the treatment. The more complex is the treatment, the more difficult the planning will be, demanding computation sophisticated methods in its execution, in order to consider the heterogeneities present in the human body. Additionally, with the appearing of new radiotherapeutic techniques, that used irradiation fields of small area, for instance, the intensity modulated radiotherapy, the difficulties for the execution of a reliable treatment planning, became still larger. In this work it was studied the influence of the lung heterogeneity in the planning of the curves of percentage depth dose, PDP, obtained with the Eclipse R planning system for different sizes of irradiation fields, using the correction algorithms for heterogeneities available in the planning system: modified Batho, general Batho and equivalent tissue-air ratio. A thorax phantom, manufactured in acrylic, containing a region made of cork to simulate the lung tissue, was used. The PDP curves generated by the planning system were compared to those obtained by Monte Carlo simulation and with the use of thermoluminescent, TL, dosimetry. It was verified that the algorithms used by the Eclipse R system for the correction of heterogeneity effects are not able to generate correct results for PDP curves in the case of small fields, occurring differences of up to 100%, when the 1x1 cm 2 treatment field is considered. These differences can cause a considerable subdosage in the lung tissue, reducing the possibility of the patient cure. (author)

  3. 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.

  4. Reduction of Absorbed Dose in Storage Phosphor Urography by Significant Lowering of Tube Voltage and Adjustment of Image Display Parameters

    International Nuclear Information System (INIS)

    Wiltz, H.J.; Petersen, U.; Axelsson, B.

    2005-01-01

    Purpose: To investigate whether image quality in storage phosphor urography can be maintained when the X-ray tube voltage is significantly lowered to give a lower patient dose. Material and Methods: Initial phantom studies were used to establish exposure settings at 53 kV that gave signal-to-noise ratios for contrast media structures equivalent to those obtained at the reference kilovoltage of 69 kV. Dose area product and image quality, assessed by image quality criteria and visual grading, were then recorded for 44 patients drawn at random to be examined by either the standard or modified technique. Results: Absorbed dose could be reduced by more than 30% without any significant change in image quality in manually controlled exposures and by 3% in exposures controlled by AEC. Conclusion: It might be possible to lower the tube voltage in digital examinations involving contrast media as a means of lowering patient dose. The image display parameters need to be adjusted to maintain image quality

  5. Contrast-enhanced radiotherapy: feasibility and characteristics of the physical absorbed dose distribution for deep-seated tumors

    Energy Technology Data Exchange (ETDEWEB)

    Garnica-Garza, H M [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional Unidad Monterrey, Via del Conocimiento 201 Parque de Investigacion e Innovacion Tecnologica, Apodaca NL C.P. 66600 (Mexico)], E-mail: hgarnica@cinvestav.mx

    2009-09-21

    Radiotherapy using kilovoltage x-rays in conjunction with contrast agents incorporated into the tumor, gold nanoparticles in particular, could represent a potential alternative to current techniques based on high-energy linear accelerators. In this paper, using the voxelized Zubal phantom in conjunction with the Monte Carlo code PENELOPE to model a prostate cancer treatment, it is shown that in combination with a 360 deg. arc delivery technique, tumoricidal doses of radiation can be delivered to deep-seated tumors while still providing acceptable doses to the skin and other organs at risk for gold concentrations in the tumor within the range of 7-10 mg-Au per gram of tissue. Under these conditions and using a x-ray beam with 90% of the fluence within the range of 80-200 keV, a 72 Gy physical absorbed dose to the prostate can be delivered, while keeping the rectal wall, bladder, skin and femoral heads below 65 Gy, 55 Gy, 40 Gy and 30 Gy, respectively. However, it is also shown that non-uniformities in the contrast agent concentration lead to a severe degradation of the dose distribution and that, therefore, techniques to locally quantify the presence of the contrast agent would be necessary in order to determine the incident x-ray fluence that best reproduces the dosimetry obtained under conditions of uniform contrast agent distribution.

  6. 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)

  7. Absorbed dose measurements in mammography using Monte Carlo method and ZrO{sub 2}+PTFE dosemeters

    Energy Technology Data Exchange (ETDEWEB)

    Duran M, H. A.; Hernandez O, M. [Departamento de Investigacion en Polimeros y Materiales, Universidad de Sonora, Blvd. Luis Encinas y Rosales s/n, Col. Centro, 83190 Hermosillo, Sonora (Mexico); Salas L, M. A.; Hernandez D, V. M.; Vega C, H. R. [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Pinedo S, A.; Ventura M, J.; Chacon, F. [Hospital General de Zona No. 1, IMSS, Interior Alameda 45, 98000 Zacatecas (Mexico); Rivera M, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, IPN, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F.(Mexico)], e-mail: hduran20_1@hotmail.com

    2009-10-15

    Mammography test is a central tool for breast cancer diagnostic. In addition, programs are conducted periodically to detect the asymptomatic women in certain age groups; these programs have shown a reduction on breast cancer mortality. Early detection of breast cancer is achieved through a mammography, which contrasts the glandular and adipose tissue with a probable calcification. The parameters used for mammography are based on the thickness and density of the breast, their values depend on the voltage, current, focal spot and anode-filter combination. To achieve an image clear and a minimum dose must be chosen appropriate irradiation conditions. Risk associated with mammography should not be ignored. This study was performed in the General Hospital No. 1 IMSS in Zacatecas. Was used a glucose phantom and measured air Kerma at the entrance of the breast that was calculated using Monte Carlo methods and ZrO{sub 2}+PTFE thermoluminescent dosemeters, this calculation was completed with calculating the absorbed dose. (author)

  8. Assessment of breast absorbed doses during thoracic computed tomography scan to evaluate the effectiveness of bismuth shielding.

    Science.gov (United States)

    Alonso, Thessa C; Mourão, Arnaldo P; Santana, Priscila C; da Silva, Teógenes A

    2016-11-01

    During a lung computed tomography (CT) examination, breast and nearby radiosensitive organs are unnecessarily irradiated because they are in the path of the primary beam. The purpose of this paper is to determine the absorbed dose in breast and nearby organs for unshielded and shielded exposures with bismuth. The experiment was done with a female anthropomorphic phantom undergoing a typical thoracic CT scan, with TLD-100 thermoluminescent detectors insert at breast, lung and thyroid positions. Results showed that dose reduction due to bismuth shielding was approximately 30% and 50% for breast and thyroid, respectively; however, the influence of the bismuth on the image quality needs to be considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The international protocol for the dosimetry of external radiotherapy beams based on standards of absorbed dose to water

    International Nuclear Information System (INIS)

    Andreo, P.

    2001-01-01

    An International Code of Practice (CoP, or dosimetry protocol) for external beam radiotherapy dosimetry based on standards of absorbed dose to water has been published by the IAEA on behalf of IAEA, WHO, PAHO and ESTRO. The CoP provides a systematic and internationally unified approach for the determination of the absorbed dose to water in reference conditions with radiotherapy beams. The development of absorbed-dose-to-water standards for high-energy photons and electrons offers the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. Many laboratories already provide calibrations at the radiation quality of 60Co gamma-rays and some have extended calibrations to high-energy photon and electron beams. The dosimetry of kilovoltage x-rays, as well as that of proton and ion beams can also be based on these standards. Thus, a coherent dosimetry system based on the same formalism is achieved for practically all radiotherapy beams. The practical use of the CoP as simple. The document is formed by a set of different CoPs for each radiation type, which include detailed procedures and worksheets. All CoPs are based on ND,w chamber calibrations at a reference beam quality Qo, together with radiation beam quality correction factors kQ preferably measured directly for the user's chamber in a standards laboratory. Calculated values of kQ are provided together with their uncertainty estimates. Beam quality specifiers are 60Co, TPR20,10 (high-energy photons), R50 (electrons), HVL and kV (x-rays) and Rres (protons and ions) [es

  10. The development of early pediatric models and their application to radiation absorbed dose calculations

    International Nuclear Information System (INIS)

    Poston, J.W.

    1989-01-01

    This presentation will review and describe the development of pediatric phantoms for use in radiation dose calculations . The development of pediatric models for dose calculations essentially paralleled that of the adult. In fact, Snyder and Fisher at the Oak Ridge National Laboratory reported on a series of phantoms for such calculations in 1966 about two years before the first MIRD publication on the adult human phantom. These phantoms, for a newborn, one-, five-, ten-, and fifteen-year old, were derived from the adult phantom. The ''pediatric'' models were obtained through a series of transformations applied to the major dimensions of the adult, which were specified in a Cartesian coordinate system. These phantoms suffered from the fact that no real consideration was given to the influence of these mathematical transformations on the actual organ sizes in the other models nor to the relation of the resulting organ masses to those in humans of the particular age. Later, an extensive effort was invested in designing ''individual'' pediatric phantoms for each age based upon a careful review of the literature. Unfortunately, the phantoms had limited use and only a small number of calculations were made available to the user community. Examples of the phantoms, their typical dimensions, common weaknesses, etc. will be discussed

  11. Hormone regulation system and cyclic nucleotids in the Chernobyl accident liquidators with doses absorbed less then 1 Gy

    International Nuclear Information System (INIS)

    Kovalenko, A.N.

    1997-01-01

    During 6 years after the accident (1987-1992) a functional state of endocrine system that regulate the adaptation, reproduction, metabolism, vessels tonicity and water-electrolyte balance were investigated in 249 liquidators with doses absorbed less then 1 Gy. The changes of these systems activity in state of basal secretion and peculiarities of their reactions under influence of perturbation (adrenaline, insulin) were revealed. Post-irradiation endocrinopathy was characterized and its role in decrease of the organism's adaptation and in mechanism of sanogenesis and pathogenesis was found. (author)

  12. Methodology for calibration of ionization chambers for X-ray of low energy in absorbed dose to water

    International Nuclear Information System (INIS)

    Oliveira, C.T.; Vivolo, V.; Potiens, M.P.A.

    2015-01-01

    The beams of low energy X-ray (10 to 150 kV) are used in several places in the world to treat a wide variety of surface disorders, and between these malignancies. As in Brazil, at this moment, there is no calibration laboratory providing the control service or calibration of parallel plate ionization chambers, the aim of this project was to establish a methodology for calibration of this kind of ionization chambers at low energy X-ray beams in terms of absorbed dose to water using simulators in the LCI. (author)

  13. Selective Internal Radiation Therapy With Yttrium-90 Glass Microspheres: Biases and Uncertainties in Absorbed Dose Calculations Between Clinical Dosimetry Models.

    Science.gov (United States)

    Mikell, Justin K; Mahvash, Armeen; Siman, Wendy; Baladandayuthapani, Veera; Mourtada, Firas; Kappadath, S Cheenu

    2016-11-15

    To quantify differences that exist between dosimetry models used for 90 Y selective internal radiation therapy (SIRT). Retrospectively, 37 tumors were delineated on 19 post-therapy quantitative 90 Y single photon emission computed tomography/computed tomography scans. Using matched volumes of interest (VOIs), absorbed doses were reported using 3 dosimetry models: glass microsphere package insert standard model (SM), partition model (PM), and Monte Carlo (MC). Univariate linear regressions were performed to predict mean MC from SM and PM. Analysis was performed for 2 subsets: cases with a single tumor delineated (best case for PM), and cases with multiple tumors delineated (typical clinical scenario). Variability in PM from the ad hoc placement of a single spherical VOI to estimate the entire normal liver activity concentration for tumor (T) to nontumoral liver (NL) ratios (TNR) was investigated. We interpreted the slope of the resulting regression as bias and the 95% prediction interval (95%PI) as uncertainty. MC NL single represents MC absorbed doses to the NL for the single tumor patient subset; other combinations of calculations follow a similar naming convention. SM was unable to predict MC T single or MC T multiple (p>.12, 95%PI >±177 Gy). However, SM single was able to predict (p<.012) MC NL single , albeit with large uncertainties; SM single and SM multiple yielded biases of 0.62 and 0.71, and 95%PI of ±40 and ± 32 Gy, respectively. PM T single and PM T multiple predicted (p<2E-6) MC T single and MC T multiple with biases of 0.52 and 0.54, and 95%PI of ±38 and ± 111 Gy, respectively. The TNR variability in PM T single increased the 95%PI for predicting MC T single (bias = 0.46 and 95%PI = ±103 Gy). The TNR variability in PM T multiple modified the bias when predicting MC T multiple (bias = 0.32 and 95%PI = ±110 Gy). The SM is unable to predict mean MC tumor absorbed dose. The PM is statistically correlated with mean MC, but the

  14. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV

    International Nuclear Information System (INIS)

    Benites R, J.; Vega C, H. R.; Velazquez F, J.

    2012-10-01

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm 3 . The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

  15. Evaluation of a deterministic grid-based Boltzmann solver (GBBS) for voxel-level absorbed dose calculations in nuclear medicine

    Science.gov (United States)

    Mikell, Justin; Cheenu Kappadath, S.; Wareing, Todd; Erwin, William D.; Titt, Uwe; Mourtada, Firas

    2016-06-01

    To evaluate the 3D Grid-based Boltzmann Solver (GBBS) code ATTILA ® for coupled electron and photon transport in the nuclear medicine energy regime for electron (beta, Auger and internal conversion electrons) and photon (gamma, x-ray) sources. Codes rewritten based on ATTILA are used clinically for both high-energy photon teletherapy and 192Ir sealed source brachytherapy; little information exists for using the GBBS to calculate voxel-level absorbed doses in nuclear medicine. We compared DOSXYZnrc Monte Carlo (MC) with published voxel-S-values to establish MC as truth. GBBS was investigated for mono-energetic 1.0, 0.1, and 0.01 MeV electron and photon sources as well as 131I and 90Y radionuclides. We investigated convergence of GBBS by analyzing different meshes ({{M}0},{{M}1},{{M}2} ), energy group structures ({{E}0},{{E}1},{{E}2} ) for each radionuclide component, angular quadrature orders (≤ft. {{S}4},{{S}8},{{S}16}\\right) , and scattering order expansions ({{P}0} -{{P}6} ); higher indices imply finer discretization. We compared GBBS to MC in (1) voxel-S-value geometry for soft tissue, lung, and bone, and (2) a source at the interface between combinations of lung, soft tissue, and bone. Excluding Auger and conversion electrons, MC agreed within  ≈5% of published source voxel absorbed doses. For the finest discretization, most GBBS absorbed doses in the source voxel changed by less than 1% compared to the next finest discretization along each phase space variable indicating sufficient convergence. For the finest discretization, agreement with MC in the source voxel ranged from  -3% to  -20% with larger differences at lower energies (-3% for 1 MeV electron in lung to  -20% for 0.01 MeV photon in bone); similar agreement was found for the interface geometries. Differences between GBBS and MC in the source voxel for 90Y and 131I were  -6%. The GBBS ATTILA was benchmarked against MC in the nuclear medicine regime. GBBS can be a viable

  16. CALCULATION STUDIES OF SPATIAL DISTRIBUTION OF THE ABSORBED DOSE RATE FOR VARIOUS SEEDS

    Directory of Open Access Journals (Sweden)

    N. A. Nerozin

    2015-01-01

    Full Text Available Purpose. Conducting computational studies of dosimetric characteristics of microsources with the radionuclide I‑125, pilot production of which is established in the research and production complex of isotope and radiopharmaceuticals, JSC “State Scientific Centre of the Russian Federation — Institute for Physics and Power Engineering named after A. I. Leypunsky” (SSC RF IPPE. Sources of production IPPE are similar to the model 6711 of the company Nicomed Amersham, dosimetric characteristics of which are standardized in accordance with the TG43 AAPM formalism.Materials and methods. Microsourse «SEED No. 6711» (model of the company Nicomed Amersham is hermetically sealed in a titanium capsule silver rod covered with a thin layer of radioactive I‑125. The half-life of iodine‑125 is 59,43 days. In the process of decay of I‑125 is converted into the Te‑125.Calculation of parameters of microsources and their comparison with the standard model 6711 is carried out with use of the computer code MCNP.Results. The method of calculation of the basic dosimetric characteristics of the microsourse SSC RF-IPPE in accordance with the TG43 formalism is developed. A comparative analysis of experimental data and calculated results by MCNP code, which allowed to identify possible reasons for differences, is performed. The estimated dose characteristics and recommended standard data for dose characteristics of micro «SEED No. 6711» are compared.Conclusions. There are two possible reasons for the differences between experimental and calculated results. The first one may be the roughness of the surface of a silver rod or diffusion of radioactive iodine in silver. The second reason might be the difference of the cross sections of the characteristic radiation of silver used in MCNP code. In the comparison of calculated dose characteristics and recommended standard the role of the application activity is very important. In compliance with the standard

  17. Optimization of Parameters in 16-slice CT-‌‌scan Protocols for Reduction of the Absorbed Dose

    Directory of Open Access Journals (Sweden)

    Shahrokh Naseri

    2014-08-01

    Full Text Available Introduction In computed tomography (CT technology, an optimal radiation dose can be achieved via changing radiation parameters such as mA, pitch factor, rotation time and tube voltage (kVp for diagnostic images. Materials and Methods In this study, the brain, abdomen, and thorax scaning was performed using Toshiba 16-slice scannerand standard AAPM and CTDI phantoms. AAPM phantom was used for the measurement of image-related parameters and CTDI phantom was utilized for the calculation of absorbed dose to patients. Imaging parameters including mA (50-400 mA, pitch factor (1 and 1.5 and rotation time (range of 0.5, 0.75, 1, 1.5 and 2 seconds were considered as independent variables. The brain, abdomen and chest imaging was performed multi-slice and spiral modes. Changes in image quality parameters including contrast resolution (CR and spatial resolution (SR in each condition were measured and determined by MATLAB software. Results After normalizing data by plotting the full width at half maximum (FWHM of point spread function (PSF in each condition, it was observed that image quality was not noticeably affected by each cases. Therefore, in brain scan, the lowest patient dose was in 150 mA and rotation time of 1.5 seconds. Based on results of scanning of the abdomen and chest, the lowest patient dose was obtained by 100 mA and pitch factors of 1 and 1.5. Conclusion It was found that images with acceptable quality and reliable detection ability could be obtained using smaller doses of radiation, compared to protocols commonly used by operators.

  18. Numerical absorbed dose distributions inside principal organs of a mathematical anthropomorphic phantom irradiated by monoenergetic photon fields

    International Nuclear Information System (INIS)

    Furstoss, C.; Menard, S.

    2005-01-01

    Full text: Personnel can be exposed to photon or mixed (neutrons and photons) radiations at workplaces for various activities (nuclear fuel cycle, medical sector, research... ). The passive and active personal dosimeters worn on the trunk evaluate the personal dose equivalent Hp(10), defined by ICRP 601 to be an estimator of the effective dose E. However, the angular and energy distributions of the radiations encountered could generate an over or under-estimation of the protection quantity E because of the response of the dosimeters or/and because of the definition of Hp(10) itself. The Institute of Radiological Protection and Nuclear Safety (IRSN) is evaluating the possibility of the measurement of the effective dose E using an instrumented anthropomorphic phantom at workplaces. Such an instrument would allow the control of the suitability of the radiological protection instrumentation used at workplaces for radiation fields which can appreciably differ from the reference ISO radiation fields used to calibrate dosimeters. The objectives of this study are to determine key positions for the future detectors inside and on the phantom, as well as their needed technical characteristics. The simulations of the organ absorbed dose distributions performed using the Monte Carlo code MCNPX2 and the MIRD phantom3 model will allow the determination of the detector locations. This paper will present the first numerical results obtained for monoenergetic parallel photon fields. The effective doses E calculated in an energy range from 15 keV to 10 MeV will be presented and compared with the results of M. Zankl et al., published in the GSF report Bericht 8/974. (author)

  19. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons; Desenvolvimento de uma metodologia para estimativa da dose absorvida e do poder de freamento para eletrons de conversao de baixa energia

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internalcontamination 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 {sup 109} Cd conversion electrons, working with a 4 {pi} 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 {sup 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)

  20. 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)

  1. Real time monitoring automation of dose rate absorbed in air due to environmental gamma radiation

    International Nuclear Information System (INIS)

    Dominguez Ley, Orlando; Capote Ferrera, Eduardo; Carrazana Gonzalez, Jorge A.; Manzano de Armas, Jose F.; Alonso Abad, Dolores; Prendes Alonso, Miguel; Tomas Zerquera, Juan; Caveda Ramos, Celia A.; Kalber, Olof; Fabelo Bonet, Orlando; Montalvan Estrada, Adelmo; Cartas Aguila, Hector; Leyva Fernandez, Julio C.

    2005-01-01

    The Center of Radiation Protection and Hygiene (CPHR) as the head institution of the National Radiological Environmental Surveillance Network (RNVRA) has strengthened its detection and response capacity for a radiological emergency situation. The measurements of gamma dose rate at the main point of the RNVRA are obtained in real time and the CPHR receives the data coming from those points in a short time. To achieve the operability of the RNVRA it was necessary to complete the existent monitoring facilities using 4 automatic gamma probes, implementing in this way a real time measurement system. The software, GenitronProbe for obtaining the data automatically from the probe, Data Mail , for sending the data via e-mail, and Gamma Red , for receiving and processing the data in the head institution ,were developed

  2. 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

  3. Use of PET Images in Assessment of Brain Absorbed Dose of Patients Undergoing [C-11] Raclopride Positron Emission Tomography

    International Nuclear Information System (INIS)

    Park, Jong O

    2005-08-01

    The positron emission tomography (PET) in combination with [C-11] raclopride is commonly used for early detection of the Parkinson's disease. Injection of considerable amount of radioactivity, typically 300∼500 MBq of [C-11] at a time, for the examination calls for attention to doses to tissues of the patient, particularly to the brain. Since [C-11] raclopride is not a common radiopharmaceutical, dosimetric data for internal dose evaluation are rare yet. In this study, an attempt was made to determine doses to the brain and the striatum of patients by use of the PET images obtained for the clinical purposes. Four informed patients suffering Parkinson's disease participated in this study. Time series of 18 frames, 35 slices in each frame, of PET images of the head were obtained. By transforming the pixel intensity in the assigned region of interests into radioactivity contents, the retention curves were constructed to evaluate the residence times. Absorbed doses to the target tissues were calculated by applying the S-values given in the MIRDOSE3.1 code. The resulting dose coefficients for the whole brain and the striatum were 0.0110±0.0016 mGy/MBq and 0.0664±0.0238 mGy/MBq, respectively. The brain dose coefficient is considerably higher than the corresponding values in other studies employing healthy subjects. This may be attributed to probable enhanced capture of [C-11] raclopride by the dopamine D 2 receptors in case of subjects with Parkinson's disease. The transcrianial magnetic stimulation (TMS) procedures are often used in treatment of Parkinson's disease. If the procedure stimulates secretion of dopamine, less retention of [C-11] raclopride is expected due to competition. So the similar assessments were made for the same patients after TMS treatments. Disappointingly, the ratios of residence time without TMS to that with TMS were 0.943±0.074 and 0.98±0.14 for the brain and the striatum, respectively. For the striatum, the ratios for three patients were

  4. Development of modern approach to absorbed dose assessment in radionuclide therapy, based on Monte Carlo method simulation of patient scintigraphy

    Science.gov (United States)

    Lysak, Y. V.; Klimanov, V. A.; Narkevich, B. Ya

    2017-01-01

    One of the most difficult problems of modern radionuclide therapy (RNT) is control of the absorbed dose in pathological volume. This research presents new approach based on estimation of radiopharmaceutical (RP) accumulated activity value in tumor volume, based on planar scintigraphic images of the patient and calculated radiation transport using Monte Carlo method, including absorption and scattering in biological tissues of the patient, and elements of gamma camera itself. In our research, to obtain the data, we performed modeling scintigraphy of the vial with administered to the patient activity of RP in gamma camera, the vial was placed at the certain distance from the collimator, and the similar study was performed in identical geometry, with the same values of activity of radiopharmaceuticals in the pathological target in the body of the patient. For correct calculation results, adapted Fisher-Snyder human phantom was simulated in MCNP program. In the context of our technique, calculations were performed for different sizes of pathological targets and various tumors deeps inside patient’s body, using radiopharmaceuticals based on a mixed β-γ-radiating (131I, 177Lu), and clear β- emitting (89Sr, 90Y) therapeutic radionuclides. Presented method can be used for adequate implementing in clinical practice estimation of absorbed doses in the regions of interest on the basis of planar scintigraphy of the patient with sufficient accuracy.

  5. Absorbed dose to water reference dosimetry using various water-equivalent solid phantoms in high-energy photon beams

    International Nuclear Information System (INIS)

    Araki, Fujio; Hanyu, Yuji; Okumura, Masahiko

    2007-01-01

    Most recent megavoltage dosimetry protocols (e.g., the Japan Society of Medical Physics (JSMP) (JSMP-01), the American Association of Physicists in Medicine (AAPM) (TG-51), and the International Atomic Energy Agency (IAEA) (TRS-398)) have limited to the use of liquid water as a phantom material for reference dose measurements. This is because water is well-defined and reproducibly available compared to water-equivalent solid phantoms. This study presents methods to determine absorbed dose to water using ionization chambers calibrated in terms of absorbed dose to water but irradiated in solid phantoms. Achieving solid phantom measurements on an absolute basis has distinct advantages in verification measurements and quality assurance. We provide a depth scaling factor that transfers a depth in the solid phantom to a water equivalent depth and an ionization conversion factor (ionization ratio) that converts a chamber reading in the solid phantom to that in water. The absorbed dose to water under reference conditions can be obtained from the solid phantom measurements by using the two factors. We calculated the depth scaling factor for four solid phantoms (Solid Water RMI457, Tough Water WE211, RW3, and MixDP) for photon energies between 4 and 18 MV. The calculated average scaling factor for each phantom agreed within 1.5% compared with the relative electron density. For various Farmer-type cylindrical chambers, we also calculated and measured the ionization conversion factor for the four solid phantoms. The solid phantom measurements were performed at many hospitals. For RMI457 and WE211, the differences between measured and calculated factors varied between -0.5% and 0.7% with the average ionization conversion factor 0.3% lower than the calculation, whereas RW3 agreed within 0.5% after one phantom examination. Similarly, the differences for MixDP ranged from -0.2% to -1.5% with the average 1.0% lower than the calculation. The composition of commercial plastic

  6. Absorbed dose estimates from a single measurement one to three days after the administration of 177Lu-DOTATATE/-TOC.

    Science.gov (United States)

    Hänscheid, Heribert; Lapa, Constantin; Buck, Andreas K; Lassmann, Michael; Werner, Rudolf A

    2017-01-01

    To retrospectively analyze the accuracy of absorbed dose estimates from a single measurement of the activity concentrations in tumors and relevant organs one to three days after the administration of 177 Lu-DOTA-TATE/TOC assuming tissue specific effective half-lives. Activity kinetics in 54 kidneys, 30 neuroendocrine tumor lesions, 25 livers, and 27 spleens were deduced from series of planar images in 29 patients. After adaptation of mono- or bi-exponential fit functions to the measured data, it was analyzed for each fit function how precise the time integral can be estimated from fixed tissue-specific half-lives and a single measurement at 24, 48, or 72 h after the administration. For the kidneys, assuming a fixed tissue-specific half-life of 50 h, the deviations of the estimate from the actual integral were median (5 % percentile, 95 % percentile): -3 °% (-15 %>; +16 °%) for measurements after 24 h, +2 %> (-9 %>; +12 %>) for measurements after 48 h, and 0 % (-2 %; +12 %) for measurements after 72 h. The corresponding values for the other tissues, assuming fixed tissue-specific half-lives of 67 h for liver and spleen and 77 h for tumors, were +2 % (-25 %; +20 %) for measurements after 24 h, +2 °% (-16 %>; +17 %>) for measurements after 48 h, and +2 %> (-11 %>; +10 %>) for measurements after 72 h. Especially for the kidneys, which often represent the dose limiting organ, but also for liver, spleen, and neuroendocrine tumors, a meaningful absorbed dose estimate is possible from a single measurement after 2, more preferably 3 days after the administration of 177 Lu-DOTA-TATE/-TOC assuming fixed tissue specific effective half-lives. Schattauer GmbH.

  7. Study of dose levels absorbed by members of the public in the nuclear medicine departments

    International Nuclear Information System (INIS)

    Cabral, Geovanna Oliveira de Mello

    2001-03-01

    In nuclear Medicine, radioisotopes are bound to various compounds (called radiopharmaceuticals) for use in various diagnostic and therapeutic applications. These unsealed sources are administered in various forms to patients, who remain radioactive for hours or days, and represent a source of potential radiation exposure for others. Thus, in nuclear medicine departments, radiation protection of workers and members of the public, especially persons accompanying patients, must consider, this exposure. In Brazil, the Comissao Nacional de Energia Nuclear (CNEN) establishes that, in nuclear medicine departments, the patients and persons accompanying should be separated each other. However, this rule is not always followed due to many factors such as physical and emotional conditions of patients. In this context, the aim of this study was the investigation of dose levels, which the persons accompanying patients are exposed to. For monitoring, thermoluminescent dosimeters were employed. The dosimeters were given to 380 persons who were accompanying patients in nuclear medicine departments. Exposure results were lower than 1 mSv. On the basis of CNEN rules, issues regarding stay conditions for members of the public in these departments are discussed. (author)

  8. Measurement of the absorbed dose in the very small size photon beams used in stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Derreumaux, S.; Huet, C.; Robbes, I.; Trompier, F.; Boisserie, G.; Brunet, G.; Buchheit, I.; Sarrazin, T.; Chea, M.

    2008-01-01

    After the radiotherapy accident in Toulouse, the French authority of nuclear safety and the French agency of health products safety have asked the IR.S.N. to establish, together with experts from the French society of medical physics and the French society of radiotherapy and oncology, a national protocol on dose calibration for the very small beams used in stereotactic radiotherapy. The research and reflexions of the working group 'GT minifaisceaux ' set up by the I.R.S.N. are presented in this final report. A review of the international literature has been performed. A national survey has been done to know the present practices in the dosimetry of small fields. A campaign of measurements of the data needed to characterize the small beams for the different stereotactic systems has started, using different types of detectors acquired by the I.R.S.N.. In this report are presented a deep synthesis on the problems related to the dosimetry of small fields, the results of the national survey, the first results of the campaign of measurements and the recommendations of the GT. (authors)

  9. 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)

  10. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  11. 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

  12. SU-F-J-56: The Connection Between Cherenkov Light Emission and Radiation Absorbed Dose in Proton Irradiated Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Darafsheh, A; Kassaee, A; Finlay, J [University of Pennsylvania, Philadelphia, PA (United States); Taleei, R [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: Range verification in proton therapy is of great importance. Cherenkov light follows the photon and electron energy deposition in water phantom. The purpose of this study is to investigate the connection between Cherenkov light generation and radiation absorbed dose in a water phantom irradiated with proton beams. Methods: Monte Carlo simulation was performed by employing FLUKA Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and Cherenkov radiation in water phantoms. The simulations were performed for proton beams with energies in the range 50–600 MeV to cover a wide range of proton energies. Results: The mechanism of Cherenkov light production depends on the initial energy of protons. For proton energy with 50–400 MeV energy that is below the threshold (∼483 MeV in water) for Cherenkov light production directly from incident protons, Cherenkov light is produced mainly from the secondary electrons liberated as a result of columbic interactions with the incident protons. For proton beams with energy above 500 MeV, in the initial depth that incident protons have higher energy than the Cherenkov light production threshold, the light has higher intensity. As the slowing down process results in lower energy protons in larger depths in the water phantom, there is a knee point in the Cherenkov light curve vs. depth due to switching the Cherenkov light production mechanism from primary protons to secondary electrons. At the end of the depth dose curve the Cherenkov light intensity does not follow the dose peak because of the lack of high energy protons to produce Cherenkov light either directly or through secondary electrons. Conclusion: In contrast to photon and electron beams, Cherenkov light generation induced by proton beams does not follow the proton energy deposition specially close to the end of the proton range near the Bragg peak.

  13. SU-E-T-120: Minimum Absorbed Dose Limit for Gafchromic EBT2 Film Response after Exposure to Low-Energy Photons.

    Science.gov (United States)

    Massillon-Jl, G; Domingo-Muñoz, I; Díaz-Aguirre, P

    2012-06-01

    To investigate the accuracy of the absorbed dose measured with Gafchromic EBT2 film in low-energy photon radiation fieldsMethods: Six EBT2 film (lot # F06110901) pieces (1cm 2 ) per dose were exposed to x-rays of 50 kV, 80 kV, 120 kV and 60Co gamma rays from a Leksell Gamma Knife at dose values from 50 mGy to 100 Gy. The x-ray beams were calibrated following the AAPMTG-61 protocol using ionization chambers calibrated at NIST or Wisconsin University depending on the beam quality, while the 60Co gamma was calibrated in water using MD-V2-55 film. Each film piece was scanned once using a HP Scanjet 7650 document flatbed scanner in transmission mode, 48-bit color at 300 dpi spatial-resolution. The data analysis was made through the ImageJ. The measured light intensity for the red channel with its associate standard deviation was used to evaluate the netOD and its standard combined uncertainty. The absorbed dose as a function of the netOD was fitted using the logistic model and the relative combined uncertainties were evaluated for each energy photon beam. EBT2 film response curve depends on the low-energy photons and the degree of energy-dependence is a function of absorbed dose. The absorbed dose relative combined uncertainty as a function of the absorbed dose indicates that the minimum absorbed dose limit is also energy dependent. Lower is the energy photon; more accurate is the measurement at low dose value. This can be explain by the fact that comparing to high energy photons, low energy photons can produce locally enough ionization density to create more color centre in the same film area. Minimum absorbed dose limit of Gafchromic EBT2 films were found to be energy dependent. The response curve depends on the low-energy photons and the degree of energy-dependence is a function of absorbed dose This work is partially supported by DGAPA-UNAM grant IN102610 and Conacyt Mexico grant 127409. © 2012 American Association of Physicists in Medicine.

  14. Evaluation of neutron irradiation fields for BNCT by using absorbed dose in a phantom

    International Nuclear Information System (INIS)

    Aizawa, O.

    1993-01-01

    In a previous paper, the author defined the open-quotes irradiation timeclose quotes as the time of irradiation in which the maximum open-quotes total background doseclose quotes becomes 2,500 RBE-cGy. In this paper, he has modified the definition a little as the time of irradiation in which the maximum open-quotes lμg/g B-10 doseclose quotes becomes 3,000 RBE-cGy, because he assumed that normal tissue contained 1μg/g B-10. Moreover, he has modified the dose criteria for BNCT as follows: The open-quotes eye doseclose quotes, open-quotes total body doseclose quotes and open-quotes except-head doseclose quotes should be less that 200, 100 and 50 RBE-cGy, respectively. He has added one more criterion for BNCT that the thermal neutron fluence at the tumor position should be over 2.5x10 12 n/cm 2 at the open-quotes irradiation timeclose quotes. The distance from the core side to the irradiation port in the open-quotes old configurationclose quotes of the Musashi reactor (TRIGA-II, 100kW) was 160 cm. He is now planning to design an eccentric core and to move the reactor core nearer to the irradiation port, distance between the core side and the irradiation port to be 140, 130 and 120cm. The other assumptions used in this paper are as follows: (1) The B-10 concentrations in tumor are 30 and/or 10μg/g. (2) The depth of the tumor is 5.0 cm to 5.5 cm from the surface. (3) The RBE values used are 1.0 for all gamma rays and 2.3 for B 10 (n,α) reaction products. (4) The RBE values for neutrons are the following three cases: the first case is using 1.6 for all neutrons; the second one is using 3.2 for non-thermal neutrons and 1.6 for thermal neutrons; the third case is using 4.8 for fast neutrons, 3.2 for faster epithermal and epithermal neutrons, and 1.6 for thermal neutrons

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Absorbed body dose simulation in Thyroid cancer therapy using MCNP4Cand ITScodes and comparison to experimental results

    International Nuclear Information System (INIS)

    Hadad, K.; Gorji, Y.

    2004-01-01

    Two standard particle transport codes of MCNP4C and integrated tiger series were used to estimate the total body dose in a thyroid cancer therapy study, with I-131 as the radionuclide source. Human body was modeled by water and soft tissue ellipsoids. Phantoms' dimensions were selected according to Brow nell recommendation. Absorbed fractions were calculated by both codes for different phantoms and for gammas with 0.364 MeV energy, which has the highest fraction in I-131 emitting gammas. Results were compared to the data published by Brow nell et.al.. Figure 1 shows the results of MCNP4C and Integrated Tiger Series with results published by Brow nell et. al.

  17. 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. 

  18. The use of the TL and OSL phenomena for determination of absorbed dose rates of 90Sr + 90Y sources by a postal method

    International Nuclear Information System (INIS)

    Antonio, Patrícia L.; Pinto, Teresa C.N.O.; Silva, Rogério M.V.; Souza, Divanizia N.; Caldas, Linda V.E.

    2014-01-01

    International recommendations establish that 90 Sr + 90 Y clinical applicators have to be calibrated in order to determine the absorbed dose rates in the case of the sources that do not have original calibration certificates, or to update the absorbed dose rates presented in the source certificates. Following these recommendations, a postal dosimetric system was developed to calibrate clinical applicators using two luminescent techniques: thermoluminescence (TL) and optically stimulated luminescence (OSL). In this work, Al 2 O 3 :C commercial detectors were characterized and their TL and OSL responses were analyzed. The results showed the efficiency and the optimal behavior of this material in beta radiation beams. After characterization, the system was sent to the Federal University of Sergipe (UFS), Brazil, for calibration of five 90 Sr + 90 Y clinical applicators, where the detectors were irradiated and returned to IPEN, for their evaluation and determination of the absorbed dose rates. A comparison between these absorbed dose rates and those adopted by the UFS as original was made; the differences obtained were within those of other studies, and they demonstrated the usefulness of the system. - Highlights: • A postal dosimetric system was developed to calibrate clinical applicators. • Al 2 O 3 :C samples were characterized in relation to their TL and OSL response. • The clinical applicators from UFS were calibrated. • The absorbed dose rates were compared with those provided on the certificates

  19. Influence of the electron energy and number of beams on the absorbed dose distributions in radiotherapy of deep seated targets

    International Nuclear Information System (INIS)

    Garnica-Garza, H.M.

    2014-01-01

    With the advent of compact laser-based electron accelerators, there has been some renewed interest on the use of such charged particles for radiotherapy purposes. Traditionally, electrons have been used for the treatment of fairly superficial lesions located at depths of no more than 4 cm inside the patient, but lately it has been proposed that by using very high energy electrons, i.e. those with an energy in the order of 200–250 MeV it should be possible to safely reach deeper targets. In this paper, we used a realistic patient model coupled with detailed Monte Carlo simulations of the electron transport in such a patient model to examine the characteristics of the resultant absorbed dose distributions as a function of both the electron beam energy as well as the number of beams for a particular type of treatment, namely, a prostate radiotherapy treatment. Each treatment is modeled as consisting of nine, five or three beam ports isocentrically distributed around the patient. An optimization algorithm is then applied to obtain the beam weights in each treatment plan. It is shown that for this particularly challenging case, both excellent target coverage and critical structure sparing can be obtained for energies in the order of 150 MeV and for as few as three treatment ports, while significantly reducing the total energy absorbed by the patient with respect to a conventional megavoltage x-ray treatment. - Highlights: • Technical requirements to be met in VHEET are established for the irradiation of prostate tumors. • Optimization of beam energy as a function of number of beams is provided. • Behavior of the non-tumor integral dose as a function of both energy and number of beams is examined

  20. Absorbed dose and biologically effective dose in patients with high-risk non-Hodgkin's lymphoma treated with high-activity myeloablative {sup 90}Y-ibritumomab tiuxetan (Zevalin registered)

    Energy Technology Data Exchange (ETDEWEB)

    Chiesa, C.; Coliva, A.; Maccauro, M.; Seregni, E.; Bombardieri, E. [Foundation IRCCS Istituto Nazionale Tumori, Nuclear Medicine Division, Milan (Italy); Botta, F. [University of Milan, Health Physics Postgraduate School, Milan (Italy); Devizzi, L.; Guidetti, A. [Foundation IRCCS Istituto Nazionale Tumori, ' ' Cristina Gandini' ' Medical Oncology, Milan (Italy); Carlo-Stella, C.; Gianni, M.A. [Foundation IRCCS Istituto Nazionale Tumori, ' ' Cristina Gandini' ' Medical Oncology, Milan (Italy); University of Milan, Medical Oncology, Milan (Italy)

    2009-11-15

    The aim of this study was to carry out two different dose estimation approaches in patients with non-Hodgkin's lymphoma (NHL) treated with a myeloablative amount of {sup 90}Y-labelled ibritumomab tiuxetan (Zevalin registered) in an open-label dose escalation study. Twenty-seven patients with relapsed/refractory or de novo high-risk NHL receiving one myeloablative dose of {sup 90}Y-ibritumomab tiuxetan followed by tandem stem cell reinfusion were evaluated for dose estimate. The injected activity was 30 MBq/kg in 12 patients and 45 MBq/kg in 15 patients. Dose estimation was performed 1 week prior to {sup 90}Y-ibritumomab tiuxetan by injection of {sup 111}In-ibritumomab tiuxetan (median activity: 200 MBq). The absorbed dose (D) and the biologically effective dose (BED) were calculated. The absorbed doses per unit activity (Gy/GBq) were [median (range)]: heart wall 4.6 (2.5-9.7), kidneys 5.1 (2.8-10.5), liver 6.1 (3.9-10.4), lungs 2.9 (1.5-6.8), red marrow 1.0 (0.5-1.7), spleen 7.0 (1.5-14.4) and testes 4.9 (2.9-16.7). The absorbed dose (Gy) for the 15 patients treated with 45 MBq/kg were: heart wall 17.0 (8.7-25.4), kidneys 17.1 (7.9-22.4), liver 20.8 (15.4-28.3), lungs 8.1 (5.4-11.4), red marrow 3.1 (2.0-4.0), spleen 26.2 (17.0-35.6) and testes 17.3 (9.0-28.4). At the highest activities the acute haematological toxicity was mild or moderate and of very short duration, and it was independent of the red marrow absorbed dose. No secondary malignancy or treatment-related myelodysplastic syndrome was observed. No non-haematological toxicity (liver, kidney, lung) was observed during a follow-up period of 24-48 months. The use of 45 MBq/kg of {sup 90}Y-ibritumomab tiuxetan in association with stem cell autografting resulted in patients being free of toxicity in non-haematological organs. These clinical findings were in complete agreement with our dose estimations, considering both organ doses and BED values. (orig.)

  1. 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 often diagnosed at an advanced stage with dissemination in the peritoneal cavity. Most patients achieve clinical remission after surgery and chemotherapy, but approximately 70% eventually experience recurrence, usually in the peritoneal cavity. To prevent recurrence, intraperitoneal (i.p.) targeted α therapy has been proposed as an adjuvant treatment for minimal residual disease after successful primary treatment. In the present study, we calculated absorbed and relative biological effect (RBE)-weighted (equivalent) doses in relevant normal tissues and estimated the effective dose associated with i.p. administration of {sup 211}At-MX35 F(ab'){sub 2}. Methods and Materials: Patients in clinical remission after salvage chemotherapy for peritoneal recurrence of ovarian cancer underwent i.p. infusion of {sup 211}At-MX35 F(ab'){sub 2}. Potassium perchlorate was given to block unwanted accumulation of {sup 211}At in thyroid and other NIS-containing tissues. Mean absorbed doses to normal tissues were calculated from clinical data, including blood and i.p. fluid samples, urine, γ-camera images, and single-photon emission computed tomography/computed tomography images. Extrapolation of preclinical biodistribution data combined with clinical blood activity data allowed us to estimate absorbed doses in additional tissues. The equivalent dose was calculated using an RBE of 5 and the effective dose using the recommended weight factor of 20. All doses were normalized to the initial activity concentration of the infused therapy solution. Results: The urinary bladder, thyroid, and kidneys (1.9, 1.8, and 1.7 mGy per MBq/L) received the 3 highest estimated absorbed doses. When the tissue-weighting factors were applied, the largest contributors to the effective dose were the lungs, stomach, and urinary bladder. Using 100 MBq/L, organ equivalent doses were less than 10% of the estimated tolerance dose. Conclusion: Intraperitoneal {sup 211}At

  2. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  3. Changing Therapeutic Paradigms: Predicting mCRC Lesion Response to Selective Internal Radionuclide Therapy (SIRT based on Critical Absorbed Dose Thresholds: A Case Study

    Directory of Open Access Journals (Sweden)

    Kathy W

    2017-01-01

    Full Text Available A 65 year old male with metastatic colorectal cancer (mCRC in the liver was referred for selective internal radionuclide therapy (SIRT following a history of extensive systemic chemotherapy. 90Y PET imaging was performed immediately after treatment and used to confirm lesion targeting and measure individual lesion absorbed doses. Lesion dosimetry was highly predictive of eventual response in the follow-up FDG PET performed 8 weeks after therapy. The derived radiation dose map was used to plan a second SIRT procedure aiming to protect healthy liver by keeping absorbed dose below the critical dose threshold, whilst targeting the remaining lesions that had received sub-critical dosing. Again, 90Y PET was performed immediately post-treatment and used to derive absorbed dose measures to both lesions and healthy parenchyma. Additional followup FDG PET imaging again confirmed the role of the 90Y PET dose map as an early predictor of response, and a tool for safe repeat treatment planning.

  4. Comparison of radiation absorbed dose in target organs in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography and computed tomography

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2009-12-01

    Full Text Available "nBackground and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT and computed tomography (CT."nMaterials and Methods: Thermoluminescent dosimeters (TLD were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. The Promax (PLANMECA, Helsinki, Finland unit was selected for Panoramic, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,USA was selected for CT examination. The average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ."nResults: The average absorbed dose for Panoramic ranged from 0.038 mGY (Buccal skin to 0.308 mGY (submandibular gland, linear tomography ranged from 0.048 mGY (Lens to 0.510 mGY (submandibular gland,CBCT ranged from 0.322 mGY (thyroid glad to 1.144 mGY (Parotid gland and in CT ranged from 2.495 mGY (sublingual gland to 3.424 mGY (submandibular gland. Total effective dose in CBCT is 5 times greater than Panoramic and 4 times greater than linear tomography, and in CT, 30 and 22 times greater than Panoramic and linear tomography, respectively. Total effective dose in CT is 6 times greater than CBCT."nConclusion: For obtaining 3-dimensional (3D information in maxillofacial region, CBCT delivers the lower dose than CT, and should be preferred over a medical CT imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation.

  5. Effect of absorbed dose and storage length on electron paramagnetic resonance (EPR) signal strength in irradiated alfalfa seeds

    International Nuclear Information System (INIS)

    Li Naining

    2006-01-01

    A kind of alfalfa seeds was irradiated by 1, 2, 3, 4 and 5 kGy at a dose rate of 6.288 kGy·h -1 in a self-shielded irradiator of 137 Cs gamma rays. The EPR spectra, which were measured subsequently between 0.3401 and 0.3501 T, showed that there was a direct proportional relationship between the EPR signal strength of free radicals produced by gamma irradiation in the alfalfa seeds and absorbed dose. The first derivative EPR spectra of the alfalfa seeds were very clear and easy to identify. However, the EPR signal strength of the peak-to-peak amplitude decreased rapidly and most of them decayed beyond 50% within 3 days after the seeds were irradiated. It tended to stabilize after half a month since the seeds were irradiated. the differences of the EPR signal strength between the irradiated and unirradiated alfalfa seeds still remained. All seeds were stored at ambient temperature for more than 3 months. Therefore, using EPR spectrometry technique to measure free radicals in alfalfa seeds as a means to determine whether the seeds have been irradiated or not is feasible, relatively fast and simple. (authors)

  6. Dose-response relationship of leukemia incidence among atomic bomb survivors and their controls by absorbed marrow dose and two types of leukemia Hiroshima and Nagasaki, October 1950 - December 1978

    International Nuclear Information System (INIS)

    Ishimaru, Toranosuke; Otake, Masanori; Ichimaru, Michito; Mikami, Motoko.

    1982-07-01

    Analysis of the relationship of the incidence of leukemia to gamma and neutron dose among atomic bomb survivors until 1971 has been reported previously by RERF. The present inquiry was prompted by the extension of case finding to 1978 and by the recent availability of new dose estimates for this fixed cohort. It is focused on the relationship of absorbed marrow dose of gamma rays and neutrons to the incidence of two types of leukemia in the fixed cohort of A-bomb survivors and their controls, the Life Span Study extended sample, in the period October 1950-December 1978. Three dose-response models have been fitted to the data on acute leukemia and chronic granulocytic leukemia. The relationship of the incidence of acute leukemia to gamma and neutron dose again suggests that the ''best'' fitting model involves a dependence on the square of the gamma dose and a linear dependence on neutrons. The estimated relative biological effectiveness (RBE) of neutrons in the induction of acute leukemia is approximately 44/√Dn(Dn = neutron dose) under this model. Based on the 95% confidence limits of the estimated RBE, the risk of this disease is estimated as 0.0026 - 0.0072 cases per million person-years per rem 2 of marrow dose. This analysis has failed, however, to produce a significant dose-response function for the incidence of chronic granulocytic leukemia in relation to the two kinds of radiation. (author)

  7. Accuracy and optimal timing of activity measurements in estimating the absorbed dose of radioiodine in the treatment of Graves' disease

    Science.gov (United States)

    Merrill, S.; Horowitz, J.; Traino, A. C.; Chipkin, S. R.; Hollot, C. V.; Chait, Y.

    2011-02-01

    Calculation of the therapeutic activity of radioiodine 131I for individualized dosimetry in the treatment of Graves' disease requires an accurate estimate of the thyroid absorbed radiation dose based on a tracer activity administration of 131I. Common approaches (Marinelli-Quimby formula, MIRD algorithm) use, respectively, the effective half-life of radioiodine in the thyroid and the time-integrated activity. Many physicians perform one, two, or at most three tracer dose activity measurements at various times and calculate the required therapeutic activity by ad hoc methods. In this paper, we study the accuracy of estimates of four 'target variables': time-integrated activity coefficient, time of maximum activity, maximum activity, and effective half-life in the gland. Clinical data from 41 patients who underwent 131I therapy for Graves' disease at the University Hospital in Pisa, Italy, are used for analysis. The radioiodine kinetics are described using a nonlinear mixed-effects model. The distributions of the target variables in the patient population are characterized. Using minimum root mean squared error as the criterion, optimal 1-, 2-, and 3-point sampling schedules are determined for estimation of the target variables, and probabilistic bounds are given for the errors under the optimal times. An algorithm is developed for computing the optimal 1-, 2-, and 3-point sampling schedules for the target variables. This algorithm is implemented in a freely available software tool. Taking into consideration 131I effective half-life in the thyroid and measurement noise, the optimal 1-point time for time-integrated activity coefficient is a measurement 1 week following the tracer dose. Additional measurements give only a slight improvement in accuracy.

  8. Risk- and cost-benefit analyses of breast screening programs derived from absorbed dose measurements in the Netherlands

    International Nuclear Information System (INIS)

    Zuur, C.; Broerse, J.J.

    1985-01-01

    Risk- and cost benefit analyses for breast screening programs are being performed, employing the risk-factors for induction of breast cancer from six extensive follow-up studies. For women of the age group above 35 years and for a risk period of 30 years after a 10-year latency period, a factor of extra cases of 20 x 10 -6 mGy -1 can be estimated. Measurements are being performed in Dutch hospitals to determine the mean absorbed tissue dose. These doses vary from 0.6 to 4.4 mGy per radiography. For a dose of 1 mGy per radiograph and yearly screening of women between 35 and 75 years, the risk of radiogenic breast cancer is about 1% of the natural incidence (85,000 per 10 6 women) in this group. A recommended frequency of screening has to be based on medical, social and financial considerations. The gain in woman years and in completely cured women is being estimated for screening with intervals of 12 instead of 24 months. The medical and social benefit is 1,520 years life-time and 69 more cases completely cured per 1,000 breast cancer patients. The financial profit of a completely cured instead of an ultimately fatal cancer can be roughly estimated at 55,000 guilders. In addition the costs per gained woman-year are about 5,000 guilders. In consequence, the extra costs of annual additional rounds of mammographic screening are balanced by the benefit. (Auth.)

  9. 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

  10. Influence of the electron energy and number of beams on the absorbed dose distributions in radiotherapy of deep seated targets.

    Science.gov (United States)

    Garnica-Garza, H M

    2014-12-01

    With the advent of compact laser-based electron accelerators, there has been some renewed interest on the use of such charged particles for radiotherapy purposes. Traditionally, electrons have been used for the treatment of fairly superficial lesions located at depths of no more than 4cm inside the patient, but lately it has been proposed that by using very high energy electrons, i.e. those with an energy in the order of 200-250MeV it should be possible to safely reach deeper targets. In this paper, we used a realistic patient model coupled with detailed Monte Carlo simulations of the electron transport in such a patient model to examine the characteristics of the resultant absorbed dose distributions as a function of both the electron beam energy as well as the number of beams for a particular type of treatment, namely, a prostate radiotherapy treatment. Each treatment is modeled as consisting of nine, five or three beam ports isocentrically distributed around the patient. An optimization algorithm is then applied to obtain the beam weights in each treatment plan. It is shown that for this particularly challenging case, both excellent target coverage and critical structure sparing can be obtained for energies in the order of 150MeV and for as few as three treatment ports, while significantly reducing the total energy absorbed by the patient with respect to a conventional megavoltage x-ray treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. 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

  12. Estimation of absorbed dose by newborn patients subjected to chest radiographs; Estimativa de dose efetiva para radiografias do torax em pediatria neonatal

    Energy Technology Data Exchange (ETDEWEB)

    Bunick, Ana P. [Faculdades Pequeno Principe, Curitiba, PR (Brazil); Schelin, Hugo R. [Instituto de Pesquisa Pele Pequeno Principe, Curitiba, PR (Brazil); Denyak, Valeriy [Hospital Infantil Pequeno Principe, Curitiba, PR (Brazil)

    2016-07-01

    The aim of this study is to present an estimate of the effective dose received by newborn patients hospitalized in NICU and subjected to X-ray examinations of the chest in the AP projection. Initially, were followed examinations chest X-rays performed on newborn patients and subsequently, simulated in a newborn simulator object. The ESAK values obtained by TLDs were used to calculate the effective dose obtained at each examination by Caldose{sub X} software. The estimated values for the effective dose in the simulated exams in this study range from 2,3μSv the 10,7μSv. The results achieved are, generally, inferior to those reported for similar previous studies. (author)

  13. 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)

  14. Angular distributions of absorbed dose of Bremsstrahlung and secondary electrons induced by 18-, 28- and 38-MeV electron beams in thick targets.

    Science.gov (United States)

    Takada, Masashi; Kosako, Kazuaki; Oishi, Koji; Nakamura, Takashi; Sato, Kouichi; Kamiyama, Takashi; Kiyanagi, Yoshiaki

    2013-03-01

    Angular distributions of absorbed dose of Bremsstrahlung photons and secondary electrons at a wide range of emission angles from 0 to 135°, were experimentally obtained using an ion chamber with a 0.6 cm(3) air volume covered with or without a build-up cap. The Bremsstrahlung photons and electrons were produced by 18-, 28- and 38-MeV electron beams bombarding tungsten, copper, aluminium and carbon targets. The absorbed doses were also calculated from simulated photon and electron energy spectra by multiplying simulated response functions of the ion chambers, simulated with the MCNPX code. Calculated-to-experimental (C/E) dose ratios obtained are from 0.70 to 1.57 for high-Z targets of W and Cu, from 15 to 135° and the C/E range from 0.6 to 1.4 at 0°; however, the values of C/E for low-Z targets of Al and C are from 0.5 to 1.8 from 0 to 135°. Angular distributions at the forward angles decrease with increasing angles; on the other hand, the angular distributions at the backward angles depend on the target species. The dependences of absorbed doses on electron energy and target thickness were compared between the measured and simulated results. The attenuation profiles of absorbed doses of Bremsstrahlung beams at 0, 30 and 135° were also measured.

  15. Absorbed Dose Distributions in Small Copper Wire Insulation due to Multiple-Sided Irradiations by 0.4 MeV Electrons

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.; Pedersen, Walther Batsberg

    1979-01-01

    When scanned electron beams are used to crosslink polymeric insulation of wire and cable, an important goal is to achieve optimum uniformity of absorbed dose distributions. Accurate measurements of dose distributions in a plastic dosimeter simulating a typical insulating material (polyethylene......) surrounding a copper wire core show that equal irradiations from as few as four sides give approximately isotropy and satisfactorily uniform energy depositions around the wire circumference. Electron beams of 0.4 MeV maximum energy were used to irradiate wires having a copper core of 1.0 mm dia...... and depth-dose profiles could be determined....

  16. Calculation of absorbed dose for skin contamination imparted by beta radiation through the VARSKIN modified code for 122 interesting isotopes for nuclear medicine, nuclear power plants and research

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1991-01-01

    In this work the implementation of a modification of the VARSKIN code for calculation of absorbed dose for contamination in skin imparted by external radiation fields generated by Beta emitting is presented. The modification consists on the inclusion of 47 isotopes of interest even Nuclear Plants for the dose evaluation in skin generated by 'hot particles'. The approach for to add these isotopes is the correlation parameter F and the average energy of the Beta particle, with relationship to those 75 isotopes of the original code. The methodology of the dose calculation of the VARSKIN code is based on the interpolation, (and integration of the interest geometries: punctual or plane sources), of the distribution functions scaled doses in water for beta and electrons punctual sources, tabulated by Berger. Finally a brief discussion of the results for their interpretation and use with purposes of radiological protection (dose insurance in relation to the considered biological effects) is presented

  17. Estimation of absorbed dose for 2-[F-18]fluoro-2-deoxy-d- glucose using whole-body positron emission tomography and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Deloar, H.M.; Fujiwara, Takehiko; Shidahara, Miho; Nakamura, Takashi; Watabe, Hiroshi; Narita, Yuichiro; Itoh, Masatoshi; Miyake, Masayasu; Watanuki, Shoichi [Cyclotron and Radioisotope Center, Tohoku Univ., Sendai (Japan)

    1998-06-01

    The purpose of this study was to measure the cumulated activity and absorbed dose in organs after i.v. administration of {sup 18}F-FDG using whole-body PET and MRI. Whole-body dynamic emission scans for {sup 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{sup -1}, 3.7 x 10{sup -2} and 2.8 x 10{sup -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{sup -2} mSv/MBq, while for the Japanese reference man of 60 kg the effective dose was 2.1 x 10{sup -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 {sup 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.) With 3 figs., 5

  18. SU-E-T-516: Measurement of the Absorbed Dose Rate in Water Under Reference Conditions in a CyberKnife Unit

    Energy Technology Data Exchange (ETDEWEB)

    Aragon-Martinez, N; Hernandez-Guzman, A [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico City, DF (Mexico); Gomez-Munoz, A [Centro Medico Nacional Siglo XXI, Mexico City, DF (Mexico); Massillon-JL, G

    2014-06-01

    Purpose: This paper aims to measure the absorbed-dose-rate in a CyberKnife unit reference-field (6cm diameter) using three ionization chambers (IC) following the new IAEA/AAPM formalism and Gafchromic film (MD-V3-55 and EBT3) protocol according to our work reported previously. Methods: The absorbed-dose-rates were measured at 90cm and 70cm SSD in a 10cmx10cm field and at 70cm SSD in a 5.4cmx5.4cm equivalent to 6cm diameter field using a linac Varian iX. All measurements were performed at 10cm depth in water. The correction factors that account for the difference between the IC response on the reference field and the CyberKnife reference field, k-(Q-msr,Q)^(f-msr,f-ref), were evaluated and Gafchromic film were calibrated using the results obtained above. Under the CyberKnife reference conditions, the factors were used to measure the absorbed-dose-rate with IC according to the new formalism and the calibrated film was irradiated in water. The film calibration curve was used to evaluate the absorbed-dose-rate in the CyberKnife unit. Results: Difference up to 2.56% is observed between dose-rate measured with IC in the reference 10cmx10cm field, depending where the chamber was calibrated, which was not reflected in the correction factor k-(Q-msr,Q)^(f-msr,f-ref ) where variations of ~0.15%-0.5% were obtained. Within measurements uncertainties, maximum difference of 1.8% on the absorbed-dose-rate in the CyberKnife reference field is observed between all IC and the films Conclusion: Absorbed-dose-rate to water was measured in a CyberKnife reference field with acceptable accuracy (combined uncertainties ~1.32%-1.73%, k=1) using three IC and films. The MD-V3-55 film as well as the new IAEA/AAPM formalism can be considered as a suitable dosimetric method to measure absorbed-dose-rate to water in small and non-standard CyberKnife fields used in clinical treatments However, the EBT3 film is not appropriated due to the high uncertainty provided (combined uncertainty ~9%, k=1

  19. Relative Importance of Hip and Sacral Pain Among Long-Term Gynecological Cancer Survivors Treated With Pelvic Radiotherapy and Their Relationships to Mean Absorbed Doses

    International Nuclear Information System (INIS)

    Waldenström, Ann-Charlotte; Olsson, Caroline; Wilderäng, Ulrica; Dunberger, Gail; Lind, Helena; Alevronta, Eleftheria; Al-Abany, Massoud; Tucker, Susan; Åvall-Lundqvist, Elisabeth; Johansson, Karl-Axel; Steineck, Gunnar

    2012-01-01

    Purpose: To investigate the relative importance of patient-reported hip and sacral pain after pelvic radiotherapy (RT) for gynecological cancer and its relationship to the absorbed doses in these organs. Methods and Materials: We used data from a population-based study that included 650 long-term gynecological cancer survivors treated with pelvic RT in the Gothenburg and Stockholm areas in Sweden with a median follow-up of 6 years (range, 2–15) and 344 population controls. Symptoms were assessed through a study-specific postal questionnaire. We also analyzed the hip and sacral dose-volume histogram data for 358 of the survivors. Results: Of the survivors, one in three reported having or having had hip pain after completing RT. Daily pain when walking was four times as common among the survivors compared to controls. Symptoms increased in frequency with a mean absorbed dose >37.5 Gy. Also, two in five survivors reported pain in the sacrum. Sacral pain also affected their walking ability and tended to increase with a mean absorbed dose >42.5 Gy. Conclusions: Long-term survivors of gynecological cancer treated with pelvic RT experience hip and sacral pain when walking. The mean absorbed dose was significantly related to hip pain and was borderline significantly related to sacral pain. Keeping the total mean absorbed hip dose below 37.5 Gy during treatment might lower the occurrence of long-lasting pain. In relation to the controls, the survivors had a lower occurrence of pain and pain-related symptoms from the hips and sacrum compared with what has previously been reported for the pubic bone.

  20. Measurement of absorbed dose-to-water for an HDR {sup 192}Ir source with ionization chambers in a sandwich setup

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Fujio; Kouno, Tomohiro; Ohno, Takeshi [Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto 862-0976 (Japan); Kakei, Kiyotaka; Yoshiyama, Fumiaki [Department of Radiotherapy, Kumamoto University Hospital, 1-1-1 Honjyo, Kumamoto 860-8556 (Japan); Kawamura, Shinji [Department of Radiotherapy, Miyazaki University Hospital, 5200 Kihara Ohaza Kiyotake-Machi, Miyazaki 889-1692 (Japan)

    2013-09-15

    Purpose: In this study, a dedicated device for ion chamber measurements of absorbed dose-to-water for a Nucletron microSelectron-v2 HDR {sup 192}Ir brachytherapy source is presented. The device uses two ionization chambers in a so-called sandwich assembly. Using this setup and by taking the average reading of the two chambers, any dose error due to difficulties in absolute positioning (centering) of the source in between the chambers is cancelled to first order. The method's accuracy was examined by comparing measurements with absorbed dose-to-water determination based on the AAPM TG-43 protocol.Methods: The optimal source-to-chamber distance (SCD) for {sup 192}Ir dosimetry was determined from ion chamber measurements in a water phantom. The {sup 192}Ir source was sandwiched between two Exradin A1SL chambers (0.057 cm{sup 3}) at the optimal SCD separation. The measured ionization was converted to the absorbed dose-to-water using a {sup 60}Co calibration factor and a Monte Carlo-calculated beam quality conversion factor, k{sub Q}, for {sup 60}Co to {sup 192}Ir. An uncertainty estimate of the proposed method was determined based on reproducibility of measurements at different institutions for the same type of source.Results: The optimal distance for the A1SL chamber measurements was determined to be 5 cm from the {sup 192}Ir source center, considering the depth dependency of k{sub Q} for {sup 60}Co to {sup 192}Ir and the chamber positioning. The absorbed dose to water measured at (5 cm, 90°) on the transverse axis was 1.3% lower than TG-43 values and its reproducibility and overall uncertainty were 0.8% and 1.7%, respectively. The measurement doses at anisotropic points agreed within 1.5% with TG-43 values.Conclusions: The ion chamber measurement of absorbed dose-to-water with a sandwich method for the {sup 192}Ir source provides a more accurate, direct, and reference dose compared to the dose-to-water determination based on air-kerma strength in the TG-43

  1. 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.)

  2. Absorbed doses received by patients submitted to chest radiographs in hospitals of the city of Sao Paulo, Brazil; Doses absorvidas pelos pacientes submetidos a radiografias toracicas em hospitais do municipio de Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Marcelo Baptista de

    2000-07-01

    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 {mu}Gy. 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

  3. 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)

  4. Absorbed doses by a technician, with and without (simulating) use of protection devices, in bone scintigraphy examination

    International Nuclear Information System (INIS)

    Jesus Lopes Filho, F. de; Antonio Filho, J.; Colaco, W.; Silveira, S.V. da

    1992-01-01

    The relation between the whole-body dose and the dose localized in body pants of a technician work in nuclear medicine was investigated by dosimetric films and thermoluminescent dosemeters. The investigation was made with and without a suitable protection devices. The results were discussed by a radiological protection view. (C.G.C.)

  5. Absorbed dose to water determination with ionization chamber dosimetry and calorimetry in restricted neutron, photon, proton and heavy-ion radiation fields.

    Science.gov (United States)

    Brede, H J; Greif, K-D; Hecker, O; Heeg, P; Heese, J; Jones, D T L; Kluge, H; Schardt, D

    2006-08-07

    Absolute dose measurements with a transportable water calorimeter and ionization chambers were performed at a water depth of 20 mm in four different types of radiation fields, for a collimated (60)Co photon beam, for a collimated neutron beam with a fluence-averaged mean energy of 5.25 MeV, for collimated proton beams with mean energies of 36 MeV and 182 MeV at the measuring position, and for a (12)C ion beam in a scanned mode with an energy per atomic mass of 430 MeV u(-1). The ionization chambers actually used were calibrated in units of air kerma in the photon reference field of the PTB and in units of absorbed dose to water for a Farmer-type chamber at GSI. The absorbed dose to water inferred from calorimetry was compared with the dose derived from ionometry by applying the radiation-field-dependent parameters. For neutrons, the quantities of the ICRU Report 45, for protons the quantities of the ICRU Report 59 and for the (12)C ion beam, the recommended values of the International Atomic Energy Agency (IAEA) protocol (TRS 398) were applied. The mean values of the absolute absorbed dose to water obtained with these two independent methods agreed within the standard uncertainty (k = 1) of 1.8% for calorimetry and of 3.0% for ionometry for all types and energies of the radiation beams used in this comparison.

  6. The development of photo-transferred thermoluminescence (PTTL) technique and its application to the routine re-assessment of absorbed dose in the NRPB automated personal dosimetry system

    Science.gov (United States)

    McKinlay, A. F.; Bartlett, D. T.; Smith, P. A.

    1980-09-01

    The re-assessment of absorbed dose has been performed routinely on customer dosimeters as part of the NRPB Automated Thermoluminescence Dosimetry Service. The technique of photo-transferred thermoluminescence (PTTL), as applied to the 2 element (LiF: PTFE discs) NRPB dosimeter inserts, is described.

  7. 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)

  8. Experimental verification by means of thermoluminescent dosimetry of the distribution dose absorbed in water for a 137Cs Amersham CDCS-M-3 source, Monte Carlo simulated

    International Nuclear Information System (INIS)

    Fragoso Valdez, F. R.; Alvarez Romero, J. T.

    2001-01-01

    It verifies, in a experimental way, the Monte Carlo simulation results (PENELOPE algorithm) for the water absorbed dose distribution, imparted by a 1 37 Cs - Amersham source (model CDCS-M-3). The feigned results are expressed in terms of the functions Α(r,z), g(r) and F(r,Θ) according to the recommendations of the AAPM TG 43 [es

  9. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment; Quantificacao de micronucleos em linfocitos de pacientes expostas a radiacao gama para a avaliacao da dose absorvida

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Isvania Maria Serafim da Silva

    2003-02-15

    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with {sup 60}Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  10. Determination of absorbed dose in crystalline and thyroid gland with irradiation protocols applied in orthopantomography equipment for dental examination

    International Nuclear Information System (INIS)

    Munoz A, A. A.; Ramirez A, L. M.; Sosa A, M. A.; Azorin V, J. C.; Vallejo H, M. A.

    2016-10-01

    Ionizing radiations are very useful in the medical field for the diagnostic use of different pathologies. Currently there are different technologies for diagnostic imaging using conventional X-ray, computed tomography, mammography, angiography, dental panoramic X-ray, among others. However, it should be noted that exposure to radiation in this type of diagnostic tests has increased considerably in recent years, because radiological examinations are not always carried out according to the actual clinical needs of each patient, increasing the risk to develop cancer. In this paper, the absorbed dose in the lens and thyroid gland was measured with the help of TLD-100 dosimeters located in a PMMA phantom adapted for orthopantomography (dental panoramic X-ray) equipment in 5 hospitals; using the parameters pre-configured for normal adult for irradiation. A Harshaw 3500 equipment was used to read the dosimeters, obtaining a value of 1.324 ± Sd 0.01 mGy for crystalline and 1.044 ± Sd 0.03 mGy values which are intended to be validated under other conditions and protocols. (Author)

  11. Comparison of the NMIJ and the ARPANSA standards for absorbed dose to water in high-energy photon beams.

    Science.gov (United States)

    Shimizu, M; Morishita, Y; Kato, M; Tanaka, T; Kurosawa, T; Takata, N; Saito, N; Ramanathan, G; Harty, P D; Oliver, C; Wright, T; Butler, D J

    2015-04-01

    The authors report the results of an indirect comparison of the standards of absorbed dose to water in high-energy photon beams from a clinical linac and (60)Co radiation beam performed between the National Metrology Institute of Japan (NMIJ) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Three ionisation chambers were calibrated by the NMIJ in April and June 2013 and by the ARPANSA in May 2013. The average ratios of the calibration coefficients for the three ionisation chambers obtained by the NMIJ to those obtained by the ARPANSA were 0.9994, 1.0040 and 1.0045 for 6-, 10- and 15-MV (18 MV at the ARPANSA) high-energy photon beams, respectively. The relative standard uncertainty of the value was 7.2 × 10(-3). The ratio for (60)Co radiation was 0.9986(66), which is consistent with the results published in the key comparison of BIPM.RI(I)-K4. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Relation between absorbed dose, charged particle equilibrium and nuclear transformations: A non-equilibrium thermodynamics point of view

    International Nuclear Information System (INIS)

    Alvarez-Romero, J. T.

    2006-01-01

    We present a discussion to show that the absorbed dose D is a time-dependent function. This time dependence is demonstrated based on the concepts of charged particle equilibrium and on radiation equilibrium within the context of thermodynamic non-equilibrium. In the latter, the time dependence is due to changes of the rest mass energy of the nuclei and elementary particles involved in the terms ΣQ and Q that appear in the definitions of energy imparted ε and energy deposit ε i , respectively. In fact, nothing is said about the averaging operation of the non-stochastic quantity mean energy imparted ε-bar, which is used in the definition of D according to ICRU 60. It is shown in this research that the averaging operation necessary to define the ε-bar employed to get D cannot be performed with an equilibrium statistical operator ρ(r) as could be expected. Rather, the operation has to be defined with a time-dependent non-equilibrium statistical operator (r, t) therefore, D is a time-dependent function D(r, t). (authors)

  13. SU-F-I-53: Coded Aperture Coherent Scatter Spectral Imaging of the Breast: A Monte Carlo Evaluation of Absorbed Dose

    Energy Technology Data Exchange (ETDEWEB)

    Morris, R [Durham, NC (United States); Lakshmanan, M; Fong, G; Kapadia, A [Carl E Ravin Advanced Imaging Laboratories, Durham, NC (United States); Greenberg, J [Duke University, Durham, NC (United States)

    2016-06-15

    Purpose: Coherent scatter based imaging has shown improved contrast and molecular specificity over conventional digital mammography however the biological risks have not been quantified due to a lack of accurate information on absorbed dose. This study intends to characterize the dose distribution and average glandular dose from coded aperture coherent scatter spectral imaging of the breast. The dose deposited in the breast from this new diagnostic imaging modality has not yet been quantitatively evaluated. Here, various digitized anthropomorphic phantoms are tested in a Monte Carlo simulation to evaluate the absorbed dose distribution and average glandular dose using clinically feasible scan protocols. Methods: Geant4 Monte Carlo radiation transport simulation software is used to replicate the coded aperture coherent scatter spectral imaging system. Energy sensitive, photon counting detectors are used to characterize the x-ray beam spectra for various imaging protocols. This input spectra is cross-validated with the results from XSPECT, a commercially available application that yields x-ray tube specific spectra for the operating parameters employed. XSPECT is also used to determine the appropriate number of photons emitted per mAs of tube current at a given kVp tube potential. With the implementation of the XCAT digital anthropomorphic breast phantom library, a variety of breast sizes with differing anatomical structure are evaluated. Simulations were performed with and without compression of the breast for dose comparison. Results: Through the Monte Carlo evaluation of a diverse population of breast types imaged under real-world scan conditions, a clinically relevant average glandular dose for this new imaging modality is extrapolated. Conclusion: With access to the physical coherent scatter imaging system used in the simulation, the results of this Monte Carlo study may be used to directly influence the future development of the modality to keep breast dose to

  14. Computerized PVC absorbance reader as the device for quick detection of dose distribution on, under and inside the electron irradiated object

    International Nuclear Information System (INIS)

    Machaj, B.; Stuglik, Z.; Panta, P.; Kaluska, I.; Bryl-Sandelewska, T.; Strzalkowski, J.; Malicki, W.

    1998-01-01

    One of the important factors in development of irradiation technology is the investigation of radiation dose distribution at the front and rear surface, sometimes also inside the irradiated object. Such information is particularly important when standard electron beam with penetration length of a few cm is used for irradiation of non-continuous objects. Use of expensive commercial dosimeter foils to technological investigations results in high cost of development of the technology. Indication of dose by commercially available PVC foils is time dependent. The investigations show anyhow that after proper thermal heating such foil gives reliable information of dose distribution within many hours after irradiation. A prototype of dose reader enabling fast read out of the dose of several PVC foils in a short time, in a form of a long band, is presented using use of the cheap standard PVC foils for measurement of dose distribution. Read out of absorbance of dosimetric foil is accomplished by two beam spectrophotometer. Such solution makes possible compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement caused by the instabilities does not exceed 0.004 A. A step motor is employed in driving mechanism for the dose reader dosimetric foil. The number of steps executed by the step motor is the measure of dosimetric foil length, that is measured with the accuracy 0.04%. Speed of dosimetric foil movement can be selected in the range 0.6cm/s-5cm/s. The dose reader is equipped with two light sources: deuterium and halogen lamps covering the light wavelengths in the range 240nm-700nm. To process the signals from the spectrophotometer and to present the measuring results a standard personal computer is employed. The measuring results are presented in the form of a diagram on the screen monitor and are stored on the computer disk

  15. Absorbed doses received by infants subjected to panoramic dental and cephalic radiographs; Dosis absorbida recibida por infantes sometidos a radiografias dentales panoramicas y cefalicas

    Energy Technology Data Exchange (ETDEWEB)

    Carrizales, L.; Carreno, S. [Instituto Venezolano de Investigaciones Cientificas. Laboratorio Secundario de Calibracion Dosimetrica. Carretera Panamericana Km. 11. Apartado Postal 21827, Caracas (Venezuela)

    1998-12-31

    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)

  16. Standardized methods to verify absorbed dose in irradiated food for insect control. Proceedings of a final research co-ordination meeting

    International Nuclear Information System (INIS)

    2001-03-01

    Irradiation to control insect infestation of food is increasingly accepted and applied, especially as a phytosanitary treatment of food as an alternative to fumigation. However, unlike other processes for insect control, irradiation does not always result in immediate insect death. Thus, it is conceivable that fresh and dried fruits and tree nuts, which have been correctly irradiated to meet insect disinfestation/quarantine requirements, may still contain live insects at the time of importation. There is, however, a movement by plant quarantine authorities away from inspecting to ensure the absence of live insects in imported consignments towards examining through administrative procedures that a treatment required by law has been given. Nevertheless, there is a need to provide plant quarantine inspectors with a reliable objective method to verify that a minimum absorbed dose of radiation was given to supplement administrative procedures. Such an objective method is expected to bolster the confidence of the inspectors in clearing the consignment without delay and to facilitate trade in irradiated commodities. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture initiated a co-ordinated research project (CRP) in 1994 to generate data on the verification of absorbed dose of irradiation in fresh, dried fruits and tree nuts for insect disinfestation/quarantine purposes. A standardized label dose indicator available commercially was used to verify the minimum/maximum absorbed dose of the irradiated commodities for these purposes as required by regulations in certain countries. It appears that such a label dose indicator with certain modifications could be made available to assist national authorities and the food industry to verify the absorbed dose of irradiation to facilitate trade in such irradiated commodities. This TECDOC reports on the accomplishments of this co-ordinated research project and includes the papers presented by the participants

  17. Implementation of an algorithm for absorbed dose calculation in high energy photon beams at off axis points

    International Nuclear Information System (INIS)

    Matos, M.F.; Alvarez, G.D.; Sanz, D.E.

    2008-01-01

    Full text: A semiempirical algorithm for absorbed dose calculation at off-axis points in irregular beams was implemented. It is well known that semiempirical methods are very useful because of their easy implementation and its helpfulness in dose calculation in the clinic. These methods can be used as independent tools for dosimetric calculation in many applications of quality assurance. However, the applicability of such methods has some limitations, even in homogeneous media, specially at off axis points, near beam fringes or outside the beam. Only methods derived from tissue-air-ratio (TAR) or scatter-maximum-ratio (SMR) have been devised for those situations, many years ago. Despite there have been improvements for these manual methods, like the Sc-Sp ones, no attempt has been made to extend their usage at off axis points. In this work, a semiempirical formalism was introduced, based on the works of Venselaar et al. (1999) and Sanz et al. (2004), aimed to the Sc-Sp separation. This new formalism relies on the separation of primary and secondary components of the beam although in a relative way. The data required by the algorithm are reduced to a minimal, allowing for experimental easy. According to modern recommendations, reference measurements in water phantom are performed at 10 cm depth, keeping away electron contamination. Air measurements are done using a mini phantom instead of the old equilibrium caps. Finally, the calculation at off-axis points are done using data measured on the central beam axis; but correcting the results with the introduction of a measured function which depends on the location of the off axis point. The measurements for testing the algorithm were performed in our Siemens MXE linear accelerator. The algorithm was used to determine specific dose profiles for a great number of different beam configurations, and the results were compared with direct measurements to validate the accuracy of the algorithm. Additionally, the results were

  18. TLD-300 detectors for separate measurement of total and gamma absorbed dose distributions of single, multiple, and moving-field neutron treatments

    International Nuclear Information System (INIS)

    Rassow, J.

    1984-01-01

    Fast neutron therapy requirements, because of the poor depth dose characteristic of present therapeutical sources, are at least as complex in treatment plans as photon therapy. The physical part of the treatment planning is very important; however, it is much more complicated than for photons or electrons owing to the need for: Separation of total and gamma absorbed dose distributions (Dsub(T) and Dsub(G)); and more stringent tissue-equivalence conditions of phantoms than in photon therapy. Therefore, methods of clinical dosimetry for the separate determination of total and gamma absorbed dose distributions in irregularly shaped (inhomogeneous) phantoms are needed. A method using TLD-300 (CaF 2 :Tm) detectors is described, which is able to give an approximate solution of the above-mentioned dosimetric requirements. The two independent doses, Dsub(T) and Dsub(G), can be calculated by an on-line computer analysis of the digitalized glow curve of TLD-300 detectors, irradiated with d(14)+Be neutrons of the cyclotron isocentric neutron therapy facility CIRCE in Essen. Results are presented for depth and lateral absorbed dose distributions (Dsub(T) and Dsub(G)) for fixed neutron beams of different field sizes compared with measurements by standard procedures (TE-TE ionization chamber, GM counter) in an A-150 phantom. The TLD-300 results for multiple and moving-field treatments (with and without wedge filters) in a patient simulating irregularly shaped (inhomogeneous) phantoms, are shown together with computer calculations of these dose distributions. The probable causes for some systematic deviations are discussed, which lead to open problems for further investigations owing to features of the detector material and the evaluation method, but mainly to differences in the composition of phantom materials used for the calculations (standard dose distributions) and TLD-300 measurements. (author)

  19. 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.

  20. The influence of the patient's posture on organ and tissue absorbed doses caused by radiodiagnostic examinations; Influencia da postura do paciente na dose absorvida em orgaos e tecidos causada por exames radiologicos

    Energy Technology Data Exchange (ETDEWEB)

    Cassola, Vagner F.; Kramer, Richard; Khoury, Helen J.; Lira, Carlos A.B.O., E-mail: vagner.cassola@gmail.co [Universidade Federal de Pernambuco (DEN/UFPE), Recife (Brazil). Dept. de Energia Nuclear

    2011-07-01

    Due to the gravitational force, organ positions and subcutaneous fat distribution change when a standing person lies down on her/his back, which is called 'supine posture'. Both postures, standing and supine, are very common in X-ray diagnosis, however, phantoms used for the simulation of patients for organ and tissue absorbed dose assessments normally represent humans either in standing or in supine posture. Consequently, the exposure scenario simulated sometimes does not match the real X-ray examination with respect to the patient's posture. Using standing and supine versions of mesh-based female and male adult phantoms, this study investigates the 'posture-effect' on organ and tissue absorbed doses for radiographs of the pelvis and the lumbar spine in order to find out if the errors from simulating the false posture are significant. (author)

  1. 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.

  2. Evaluation of absorbed radiation dose rate in a didactic X-ray equipment; Avaliacao da taxa de dose absorvida em um equipamento de raios-X didatico

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Phelipe Amaral Ferreira; Perini, Ana Paula; Neves, Lucio Pereira, E-mail: lucio.neves@ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Fisica

    2016-07-01

    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)

  3. Radioiodine therapy in Graves' disease based on tissue-absorbed dose calculations: effect of pre-treatment thyroid volume on clinical outcome

    International Nuclear Information System (INIS)

    Reinhardt, Michael J.; Joe, Alexius Y.; Mallek, Dirk von; Ezziddin, Samer; Palmedo, Holger; Brink, Ingo; Krause, Thomas M.

    2002-01-01

    This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15±9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256±80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses. (orig.)

  4. Review of personal monitoring techniques for the measurement of absorbed dose from external beta and low energy photon radiation

    DEFF Research Database (Denmark)

    Christensen, Poul

    1986-01-01

    The techniques available at present for personal monitoring of doses from external beta and low energy photon radiation are reviewed. The performance of currently used dosimetry systems is compared with that recommended internationally, and developments for improving the actual performance...

  5. Estimation of absorbed dose of radiosensitive organs and effective sose in patients underwent abdominopelvic spiral CT scan using impact CT patient dosimetry

    Directory of Open Access Journals (Sweden)

    Ayoub Amirnia

    2017-05-01

    Full Text Available Background: Due to the presence of radiosensitive organs in the abdominopelvic region and increasing the number of requests for CT scan examinations, concerns about increasing radiation doses in patients has been greatly elevated. Therefore, the goal of this study was to determine the absorbed dose of radiosensitive organs and the effective dose in patients underwent abdominopelvic CT scan using ImPACT CT patient dosimetry Calculator (version 1.0.4, Imaging Performance Assessment on Computed Tomography, www.impactscan.org. Methods: This prospective cross-sectional study was conducted in Imam Reza Hospital from November to February 2015 February 2015 in the Imam Reza Hospital, in Urmia, Iran. The demographic and dosimetric information of 100 patients who underwent abdominopelvic CT scan in a 6-slice CT scanner were obtained through the data collection forms. The demographic data of the patients included age, weight, gender, and BMI. The dosimetric parameters included pitch value, CT dose volume index (CTDIvol, dose-length product (DLP, tube voltage, tube current, exposure time, collimation size, scan length, and scan time. To determine the absorbed dose of radiosensitive organs and also the effective dose in patients, ImPACT CT patient dosimetry calculator was used. Results: The results of this study demonstrated that the mean and standard deviation (SD of patients' effective dose in abdominopelvic CT scan was 4.927±0.164 mSv. The bladder in both genders had the greatest mean organ dose, which was 64.71±17.15 mGy for men and 77.56±18.48 mGy for women (P<0.001. Conclusion: The effective dose values of this examination are in the same range as previous studies, as well as International Commission on Radiological Protection (ICRP recommendations. However, the radiation dose from CT scan has the largest contribution to the medical imaging. According to the ALARA principle, it is recommended that the scan parameters, especially mAs, should be

  6. Dependence of the average life span, mortality and osteosarcoma occurence in rats on the radiation dose absorbed (Sr 90)

    International Nuclear Information System (INIS)

    Shvedov, V.L.; Panteleev, L.I.

    1975-01-01

    The dose dependence of mortality and osteosarcoma development frequency is studied in white rats which have received 0.00005-5.0μCi/day of strontium-90 throughout their lives. It is shown that total mortality in the dose range 0-10 krad is a more sensitive test than osteosarcoma frequency, osteosarcomatosis hardly reducing the mean life span of the irradiated rats. (author)

  7. 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.

  8. 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

  9. Absorbed doses by the thyroid follicles due to the short half-lives isotope; Dose absorvida pelos foliculos tireoideanos devido aos isotopos de iodo de meia-vida curta

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Laelia; Amaral, Ademir; Colas-Linhart, Nicole; Hindie, Elif; Oliveira, Jairo R. de; Oliveira, Pedro A.R. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia (GERAR); Universite Paris 7, Paris Cedex 18 (France). Faculte de Medecine Xavier Bichat. Lab. de Chimie et Biophysique des Traceurs; Paris Cedex 12 (France). Hopital Saint-Antoine. Service de Medecine Nucleaire; Universidade Federal de Pernambuco UFPE, Recife, PE (Brazil). Dept. de Fisica e Matematica; E-mails: lpbcampos@uol.com.br; amaral@ufpe.br

    2005-11-15

    The aim of this work is to evaluate the contributions of internally deposited short-lived iodines to the dose absorbed by thyroid's follicle, in the case of nuclear accidents . Dose calculation was carried out, at follicular level, for {sup 131} I and short-lived iodines ({sup 132}I, {sup 133}I, {sup 134}I and {sup 135}I), using the code MCNP4C. The thyroid's follicles were modeled as spheres, with different diameters (between 40 to 240 {mu}m), having the same density as for soft tissue ({rho} = 1.04 g.cm{sup -3}). The results showed that the contribution of short-lived iodines for total dose is about 72%. The results reported in this work pointed out that, in case of nuclear accidents, the contributions of the short-lived iodines to the total dose absorbed by thyroid, at follicular level, cannot be neglected in a prospective evaluation of risks associated to internal contamination by radioactive iodine.(author)

  10. A 3D Monte Carlo Method for Estimation of Patient-specific Internal Organs Absorbed Dose for 99mTc-hynic-Tyr3-octreotide Imaging

    International Nuclear Information System (INIS)

    Momennezhad, Mehdi; Nasseri, Shahrokh; Zakavi, Seyed Rasoul; Parach, Ali Asghar; Ghorbani, Mahdi; Asl, Ruhollah Ghahraman

    2016-01-01

    Single-photon emission computed tomography (SPECT)-based tracers are easily available and more widely used than positron emission tomography (PET)-based tracers, and SPECT imaging still remains the most prevalent nuclear medicine imaging modality worldwide. The aim of this study is to implement an image-based Monte Carlo method for patient-specific three-dimensional (3D) absorbed dose calculation in patients after injection of 99m Tc-hydrazinonicotinamide (hynic)-Tyr 3 -octreotide as a SPECT radiotracer. 99m Tc patient-speci@@@@@@c S values and the absorbed doses were calculated with GATE code for each source-target organ pair in four patients who were imaged for suspected neuroendocrine tumors. Each patient underwent multiple whole-body planar scans as well as SPECT imaging over a period of 1-24 h after intravenous injection of 99m hynic-Tyr 3 -octreotide. The patient-specific S values calculated by GATE Monte Carlo code and the corresponding S values obtained by MIRDOSE program differed within 4.3% on an average for self-irradiation, and differed within 69.6% on an average for cross-irradiation. However, the agreement between total organ doses calculated by GATE code and MIRDOSE program for all patients was reasonably well (percentage difference was about 4.6% on an average). Normal and tumor absorbed doses calculated with GATE were slightly higher than those calculated with MIRDOSE program. The average ratio of GATE absorbed doses to MIRDOSE was 1.07 ± 0.11 (ranging from 0.94 to 1.36). According to the results, it is proposed that when cross-organ irradiation is dominant, a comprehensive approach such as GATE Monte Carlo dosimetry be used since it provides more reliable dosimetric results

  11. Determination of absorbed dose to water from a miniature kilovoltage x-ray source using a parallel-plate ionization chamber

    Science.gov (United States)

    Watson, Peter G. F.; Popovic, Marija; Seuntjens, Jan

    2018-01-01

    Electronic brachytherapy sources are widely accepted as alternatives to radionuclide-based systems. Yet, formal dosimetry standards for these devices to independently complement the dose protocol provided by the manufacturer are lacking. This article presents a formalism for calculating and independently verifying the absorbed dose to water from a kV x-ray source (The INTRABEAM System) measured in a water phantom with an ionization chamber calibrated in terms of air-kerma. This formalism uses a Monte Carlo (MC) calculated chamber conversion factor, CQ , to convert air-kerma in a reference beam to absorbed dose to water in the measurement beam. In this work CQ was determined for a PTW 34013 parallel-plate ionization chamber. Our results show that CQ was sensitive to the chamber plate separation tolerance, with differences of up to 15%. CQ was also found to have a depth dependence which varied with chamber plate separation (0 to 10% variation for the smallest and largest cavity height, over 3 to 30 mm depth). However for all chamber dimensions investigated, CQ was found to be significantly larger than the manufacturer reported value, suggesting that the manufacturer recommended method of dose calculation could be underestimating the dose to water.

  12. Role of shielding in modulating the effects of solar particle events: Monte Carlo calculation of absorbed dose and DNA complex lesions in different organs

    Science.gov (United States)

    Ballarini, F.; Biaggi, M.; De Biaggi, L.; Ferrari, A.; Ottolenghi, A.; Panzarasa, A.; Paretzke, H. G.; Pelliccioni, M.; Sala, P.; Scannicchio, D.; Zankl, M.

    2004-01-01

    Distributions of absorbed dose and DNA clustered damage yields in various organs and tissues following the October 1989 solar particle event (SPE) were calculated by coupling the FLUKA Monte Carlo transport code with two anthropomorphic phantoms (a mathematical model and a voxel model), with the main aim of quantifying the role of the shielding features in modulating organ doses. The phantoms, which were assumed to be in deep space, were inserted into a shielding box of variable thickness and material and were irradiated with the proton spectra of the October 1989 event. Average numbers of DNA lesions per cell in different organs were calculated by adopting a technique already tested in previous works, consisting of integrating into "condensed-history" Monte Carlo transport codes - such as FLUKA - yields of radiobiological damage, either calculated with "event-by-event" track structure simulations, or taken from experimental works available in the literature. More specifically, the yields of "Complex Lesions" (or "CL", defined and calculated as a clustered DNA damage in a previous work) per unit dose and DNA mass (CL Gy -1 Da -1) due to the various beam components, including those derived from nuclear interactions with the shielding and the human body, were integrated in FLUKA. This provided spatial distributions of CL/cell yields in different organs, as well as distributions of absorbed doses. The contributions of primary protons and secondary hadrons were calculated separately, and the simulations were repeated for values of Al shielding thickness ranging between 1 and 20 g/cm 2. Slight differences were found between the two phantom types. Skin and eye lenses were found to receive larger doses with respect to internal organs; however, shielding was more effective for skin and lenses. Secondary particles arising from nuclear interactions were found to have a minor role, although their relative contribution was found to be larger for the Complex Lesions than for

  13. Evaluation of absorbed and effective doses to patients from radiopharmaceuticals using the ICRP 110 reference computational phantoms and ICRP 103 formulation

    International Nuclear Information System (INIS)

    Hadid, L.; Gardumi, A.; Desbree, A.

    2013-01-01

    In diagnostic nuclear medicine, mean absorbed doses to patients' organs and effective doses are published for standard stylised anatomic models. To provide more realistic and detailed geometries of the human morphology, the International Commission on Radiological Protection (ICRP) has recently adopted male and female voxel phantoms to represent the reference adult. This work investigates the impact of the use of these new computational phantoms. The absorbed doses were calculated for 11 different radiopharmaceuticals currently used in diagnostic nuclear medicine. They were calculated for the ICRP 110 reference computational phantoms using the OEDIPE software and the MCNP extended Monte Carlo code. The biokinetic models were issued from ICRP Publications 53, 80 and 106. The results were then compared with published values given in these ICRP Publications. To discriminate the effect of anatomical differences on organ doses from the effect of the calculation method, the Monte Carlo calculations were repeated for the reference adult stylised phantom. The voxel effect, the influence of the use of different densities and nuclear decay data were also investigated. Effective doses were determined for the ICRP 110 adult reference computational phantom with the tissue weighting factor of ICRP Publication 60 and the tissue weighting factors of ICRP Publication 103. The calculation method and, in particular, the simulation of the electron transport have a significant influence on the calculated doses, especially, for small and walled organs. Overestimates of >200 % were observed for the urinary bladder wall of the stylised phantom compared with the computational phantoms. The unrealistic organ topology of the stylised phantom leads to important dose differences, sometimes by an order of magnitude. The effective doses calculated using the new computational phantoms and the new tissue weighting factors are globally lower than the published ones, except for some

  14. Estimation of absorbed dose of the patients undergoing X-ray examination in some hospitals of Malopolska District in Poland

    International Nuclear Information System (INIS)

    Wasilewska-Radwanska, M.; Balasa, A.; Araszkiewicz, E.; Gajewski, W.

    2004-01-01

    This paper describes some examples of quality control studies performed for selected conventional radiographic equipment that are routinely used in x-ray laboratories of eight hospitals in Malopolska district. The main goals of the quality control program are to minimize dose to patients and to staff as well as to optimize image quality. To estimate patient doses obtained during diagnostic X-ray examinations two kinds of devices were used: REX-reference phantom and CONNY II dosemeter. The control tests have been performed for the following X-ray examinations: a) urinary tract (AP) at 80 kV; b) chest (LAT) at 100 kV; c) chest (LAT) at 120 kV. The entrance doses measured at eight selected radiological departments are shown as well as reference dose levels recommended by WHO for each examination. The most of experimental data shows values smaller than limits recommended by WHO. Only in S7 the entrance dose for chest examination (both at 100 kV and at 120 kV) are greater. All results of the X-ray tube quality control are presented for the seven laboratories. The present situation in quality of selected X-ray units in Malopolska district indicates clearly the need for performing quality assurance tests regularly with possibility to put aside the equipment which does not comply with the reference levels as result of new regulations ordered by Polish Minister of Health

  15. Evaluation of the absorbed dose during studies of the renal function due to I123 / I131 (hippuran) and In111 (DTPA)

    International Nuclear Information System (INIS)

    Vasquez, M.; Castillo, C.; Sarachaga, R.; Rojas, R.; Zelada, L.; Melendez, J.; Gomez, M.; Diaz, E.

    2014-08-01

    Using the methodology MIRD and representation Cristy-Eckerman for kidneys, bladder, and whole body as organs of the bio-kinetics of I 123 / I 131 (hippuran) and the In 111 (D PTA), the absorbed dose for studies of the renal function of adults due to the I 123 is 0,0071 mGy/MBq where 88.16% corresponds to its auto-dose and 11,96% to the organs of their bio-kinetics; while for the I 131 their dose is 0,032 mGy/MBq where 95,03% corresponds to its auto-dose and 4,97% to the organs of their bio-kinetics. For the In 111 their dose is 0,0168 mGy/MBq where 71,68% corresponds to their auto-dose and 28,32% to the organs of their bio-kinetics. In all the cases the dosimetric contributions of the organs of the bio-kinetics (whole body and urinary bladder) are very significant, and this fundamentally is due to the photons of the whole body. (Author)

  16. 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)

  17. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

    A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

  18. Synthesis of poly (acrylamide-co-metacrylic acid) hydrogels By means of gamma irradiation techniques: influence of Absorbed dose on the swelling process

    International Nuclear Information System (INIS)

    Rapado, Manuel; Altanes, Sonia; Sainz, Dianelys; Prado, Stalina

    1999-01-01

    In this report gamma radiation techniques were performed a double function of proceeding the processes of polymerization and crosslinking with the advantage of avoid the uses of chemicals crosslinks. The influence of absorbed dose on the swelling ratio as a function of pH have been presented. For these hydrogels, swelling studies indicated that swelling decrease with the increase of the absorbed dose from 10 to 50 kGy. It was confirmed that at the firsts stages (100-150 min) the diffusion studies were in accordance with Fickian behavior and the diffusion coefficients were obtained, whereas the latest stages were in good agreement with second-order diffusion kinetics proposed by Schott 1 .These news hydrogels exhibit a higher degree of swelling, a factor that, a priori, assures high biocompatibility because it increases the similarity with living tissues

  19. 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

  20. Detection and quantification of223Ra uptake in bone metastases of patients with castration resistant prostate carcinoma, with the aim of determining the absorbed dose in the metastases.

    Science.gov (United States)

    Mínguez, P; Gómez de Iturriaga, A; Fernández, I L; Rodeño, E

    To obtain the necessary acquisition and calibration parameters in order to evaluate the possibility of detecting and quantifying 223 Ra uptake in bone metastases of patients treated for castration resistant prostate carcinoma. Furthermore, in the cases in which the activity can be quantified, to determine the absorbed dose. Acquisitions from a Petri dish filled with 223 Ra were performed in the gamma camera. Monte Carlo simulations were also performed to study the partial volume effect. Formulae to obtain the detection and quantification limits of 223 Ra uptake were applied to planar images of two patients 7 days post-administration of 55kBq/kg of 223 Ra. In order to locate the lesions in advance, whole-body scans and SPECT/CT images were acquired after injecting 99m Tc-HDP. The optimal energy window was found to be at 82keV with a medium-energy collimator MEGP. Of the lesions found in the patients, only those that had been detected in both the AP and PA projections could be quantified. These lesions were those which had shown a higher 99m Tc-HDP uptake. The estimated values of absorbed doses ranged between 0.7Gy and 7.8Gy. Of the lesions that can be detected, it is not possible to quantify the activity uptake in some of them, which means that the absorbed dose cannot be determined either. This does not mean that the absorbed dose in these lesions can be regarded as negligible. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  1. Absorbed Doses and Risk Estimates of (211)At-MX35 F(ab')2 in Intraperitoneal Therapy of Ovarian Cancer Patients

    DEFF Research Database (Denmark)

    Cederkrantz, Elin; Andersson, Håkan; Bernhardt, Peter

    2015-01-01

    PURPOSE: Ovarian cancer is often diagnosed at an advanced stage with dissemination in the peritoneal cavity. Most patients achieve clinical remission after surgery and chemotherapy, but approximately 70% eventually experience recurrence, usually in the peritoneal cavity. To prevent recurrence...... dose associated with i.p. administration of (211)At-MX35 F(ab')2. METHODS AND MATERIALS: Patients in clinical remission after salvage chemotherapy for peritoneal recurrence of ovarian cancer underwent i.p. infusion of (211)At-MX35 F(ab')2. Potassium perchlorate was given to block unwanted accumulation...... of the infused therapy solution. RESULTS: The urinary bladder, thyroid, and kidneys (1.9, 1.8, and 1.7 mGy per MBq/L) received the 3 highest estimated absorbed doses. When the tissue-weighting factors were applied, the largest contributors to the effective dose were the lungs, stomach, and urinary bladder. Using...

  2. Assessment of Brain absorbed X-ray dose during CT- Scan using ImPACT software in Tehran Univeristy hospitals

    Directory of Open Access Journals (Sweden)

    Khalilpour M

    2009-07-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 st1":*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: CT scan was first introduced into clinical practice in 1972, and since then has grown into one of the predominant diagnostic procedures. In 1998, the UK National Radiological Protection Board reported that 20% of the national collective dose from medical X-ray examinations derived from CT-scans, although it represented only 2% of all X- ray examinations the aim of this study was to determine the X-ray dosage received by patients in brain CT scan."n"n Methods: In this work, we have estimated patient dose arising from CT examination of brain in five hospitals in Tehran. Organ and effective doses were estimated for 150 patients who underwent CT examination of brain. "ImPACT" version 0.99v was used to estimate organ and effective dose. Brain examinations were performed with fixed Kvp, mAs and T (slice thickness for each scanner. "n"n Results: Patients, who were scanned by CT of emam Khomeini center (Toshiba Xvision /EX Scanner, received maximum organ dose (brain and minimum organ dose was delivered to patients who were scanned by CT of amir alam center (Toshiba Xvision /EX Scanner. Maximum effective dose was 1.7 mSv acquired in this study for emam Khomeini haspital, smaller than

  3. Prediction of Therapy Tumor-Absorbed Dose Estimates in I-131 Radioimmunotherapy Using Tracer Data Via a Mixed-Model Fit to Time Activity

    Science.gov (United States)

    Koral, Kenneth F.; Avram, Anca M.; Kaminski, Mark S.; Dewaraja, Yuni K.

    2012-01-01

    Abstract Background For individualized treatment planning in radioimmunotherapy (RIT), correlations must be established between tracer-predicted and therapy-delivered absorbed doses. The focus of this work was to investigate this correlation for tumors. Methods The study analyzed 57 tumors in 19 follicular lymphoma patients treated with I-131 tositumomab and imaged with SPECT/CT multiple times after tracer and therapy administrations. Instead of the typical least-squares fit to a single tumor's measured time-activity data, estimation was accomplished via a biexponential mixed model in which the curves from multiple subjects were jointly estimated. The tumor-absorbed dose estimates were determined by patient-specific Monte Carlo calculation. Results The mixed model gave realistic tumor time-activity fits that showed the expected uptake and clearance phases even with noisy data or missing time points. Correlation between tracer and therapy tumor-residence times (r=0.98; ptracer-predicted and therapy-delivered mean tumor-absorbed doses (r=0.86; ptracer study for tumor dosimetry-based treatment planning in RIT. PMID:22947086

  4. 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)

  5. 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)

  6. A comparison of Australian and Canadian calibration coefficients for air kerma and absorbed dose to water for 60Co gamma radiation.

    Science.gov (United States)

    Shortt, K R; Huntley, R B; Kotler, L H; Boas, J F; Webb, D V

    2006-06-01

    Australian and Canadian calibration coefficients for air kerma and absorbed dose to water for 60Co gamma radiation have been compared using transfer standard ionization chambers of types NE 2561 and NE 2611A. Whilst the primary standards of air kerma are similar, both being thick-walled graphite cavity chambers but employing different methods to evaluate the Awall correction, the primary standards of absorbed dose to water are quite different. The Australian standard is based on measurements made with a graphite calorimeter, whereas the Canadian standard uses a sealed water calorimeter. The comparison result, expressed as a ratio of calibration coefficients R=N(ARPANSA)/N(NRC), is 1.0006 with a combined standard uncertainty of 0.35% for the air kerma standards and 1.0052 with a combined standard uncertainty of 0.47% for the absorbed dose to water standards. This demonstrates the agreement of the Australian and Canadian radiation dosimetry standards. The results are also consistent with independent comparisons of each laboratory with the BIPM reference standards. A 'trilateral' analysis confirms the present determination of the relationship between the standards, within the 0.09% random component of the combined standard uncertainty for the three comparisons.

  7. Absorbed dose to water comparison between NE 2561 and NE 2671 chambers using IAEA, HPA and NACP protocols for gamma ray beam

    International Nuclear Information System (INIS)

    Mohd Taufik Dolah; Noriah Mod Ali; Taiman Kadni

    2002-01-01

    The aim of this study to evaluate the performance of NE 2571 chamber in comparison with NE 2561 chamber in determination of the absorbed dose to water in gamma ray beam. In this study NE 2561 is taking as a reference standard chamber while NE 2571 as a working standard. Irradiation of chamber (alternately) was performed at a reference depth, 5 cm, inside the IAEA water phantom. Both chambers were exposed to 13 difference exposures of gamma rays. The values of absorbed dose to water were then determined using IAEA, HPA and NACP protocols. Deviations of absorbed dose determined by NE 2561 and NE 2571 were calculated for each protocol. result obtained in terms of [protocol, μ (mean deviation) ± σ s e (standard error)] were (IAEA, 1.12 ± 0.04], [HPA, 0.09 ± 0.04], and [NCP, 0.09 ± 0.04]. It can be concluded that NE 2571 shown acceptable performance as it is within acceptable limit ± 3%. (Author)

  8. Absorbed dose in the fetus of a pregnant patient when I131 (iodide/Tc99m (pertechnetate) is administered during thyroid studies

    International Nuclear Information System (INIS)

    Vasquez A, M.; Murillo C, V.; Arbayza F, J.; Sanchez S, P.; Cabrera S, C.

    2016-10-01

    The radiation absorbed dose in the fetus of a pregnant woman during thyroid studies is estimated through the analysis of the bio-kinetics of radiopharmaceuticals containing I 131 (iodide) or Tc 99m (pertechnetate). MIRD formalism and its representation Cristy-Eckerman are used. The results indicate that the absorbed dose by the fetus of a woman of 3, 6 and 9 months of gestation due to Tc 99m emissions is lower than that obtained by I 131 ; represent 34.7%, 6% and 3.5% of the dose generate by the iodide. The auto-dose in the fetus of a pregnant woman is mainly due to the local energy deposition of the beta and gamma emissions of I 131 , being greater than the one reported by the gamma emissions and conversion electrons of the Tc 99m , for fetuses of 6 and 9 months. The dose incorporated to the fetus due to the organs of the maternal tissues, which are part of the bio-kinetics, are basically due to the emission of its gamma photons and correspond to 38.50% /60.52% in fetuses of 3 months, 64.71% /12.43% in fetuses of 6 months and 69.79% /10.97% in fetuses of 9 months for the radiopharmaceuticals Tc 99m (pertechnetate) / I 131 (iodide). The organs of bio-kinetics that contribute to the fetus dose are mainly due to the bladder, followed by the rest, and small intestine (fetuses of 3 months); of the rest, followed by the small intestine and bladder (fetuses of 6 months); of the bladder, followed by the small intestine and stomach (fetuses of 9 months) when using I 131 ; while for the Tc 99m the bladder and rest contribute (fetuses of 3 months); of the placenta, followed by the rest and bladder (fetuses of 6 and 9 months). (Author)

  9. Differences among Monte Carlo codes in the calculations of voxel S values for radionuclide targeted therapy and analysis of their impact on absorbed dose evaluations.

    Science.gov (United States)

    Pacilio, M; Lanconelli, N; Lo, Meo S; Betti, M; Montani, L; Torres, Aroche L A; Coca, Pérez M A

    2009-05-01

    Several updated Monte Carlo (MC) codes are available to perform calculations of voxel S values for radionuclide targeted therapy. The aim of this work is to analyze the differences in the calculations obtained by different MC codes and their impact on absorbed dose evaluations performed by voxel dosimetry. Voxel S values for monoenergetic sources (electrons and photons) and different radionuclides (90Y, 131I, and 188Re) were calculated. Simulations were performed in soft tissue. Three general-purpose MC codes were employed for simulating radiation transport: MCNP4C, EGSnrc, and GEANT4. The data published by the MIRD Committee in Pamphlet No. 17, obtained with the EGS4 MC code, were also included in the comparisons. The impact of the differences (in terms of voxel S values) among the MC codes was also studied by convolution calculations of the absorbed dose in a volume of interest. For uniform activity distribution of a given radionuclide, dose calculations were performed on spherical and elliptical volumes, varying the mass from 1 to 500 g. For simulations with monochromatic sources, differences for self-irradiation voxel S values were mostly confined within 10% for both photons and electrons, but with electron energy less than 500 keV, the voxel S values referred to the first neighbor voxels showed large differences (up to 130%, with respect to EGSnrc) among the updated MC codes. For radionuclide simulations, noticeable differences arose in voxel S values, especially in the bremsstrahlung tails, or when a high contribution from electrons with energy of less than 500 keV is involved. In particular, for 90Y the updated codes showed a remarkable divergence in the bremsstrahlung region (up to about 90% in terms of voxel S values) with respect to the EGS4 code. Further, variations were observed up to about 30%, for small source-target voxel distances, when low-energy electrons cover an important part of the emission spectrum of the radionuclide (in our case, for 131I

  10. 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)

  11. Project ''PHANTOM'' - measurement of the absorbed dose, the ''averaged LET'' and the thermal neutron fluence in a tissue equivalent Phantom onboard space station MIR

    International Nuclear Information System (INIS)

    Berger, T.; Hajek, M.; Vana, N.; Schoener, W.; Akatov, Y.; Shurshakov, V.; Arkhangelsky, V.

    2001-01-01

    A water filled phantom with a diameter of 35 cm was developed at the Institute for Biomedical Problems. This tissue equivalent phantom is equipped with 4 channels to deposit dosemeters in different depths. In the framework of the project 'PHANTOM' (phase 1-3) thermoluminescent dosemeters of the commercially available Types TLD - 600 and TLD - 700 were exposed from May 1997 to February 1999 for an overall of 572 days in the different channels (perpendicular and normal to the hull of the spacecraft) of the phantom. The phantom was positioned in the commander cabin, the board engineer cabin and in the module KWANT 2. Besides the measurement of the depth dose distribution, the 'averaged LET' was determined using the HTR - method. The HTR - method utilizes the different LET - efficiencies of the main - and the high temperature glow peaks of LiF dosemeters for the evaluation of the 'averaged LET' in mixed radiation fields. Therefore it is possible to calculate the depth distribution of the biologically relevant dose equivalent. The results show, that despite of the depth decrease of the absorbed dose, the depth dose equivalent is almost constant. This can be explained by the production of secondary particles inside the phantom. The flux of the thermal neutrons was determined using the pair method. Calibration was performed at the research reactor of the Austrian Universities. First results show, that the contribution of thermal neutrons are roughly 10% of the total neutron dose equivalent. (orig.) [de

  12. A methodological approach to a realistic evaluation of skin absorbed doses during manipulation of radioactive sources by means of GAMOS Monte Carlo simulations

    Science.gov (United States)

    Italiano, Antonio; Amato, Ernesto; Auditore, Lucrezia; Baldari, Sergio

    2018-05-01

    The accurate evaluation of the radiation burden associated with radiation absorbed doses to the skin of the extremities during the manipulation of radioactive sources is a critical issue in operational radiological protection, deserving the most accurate calculation approaches available. Monte Carlo simulation of the radiation transport and interaction is the gold standard for the calculation of dose distributions in complex geometries and in presence of extended spectra of multi-radiation sources. We propose the use of Monte Carlo simulations in GAMOS, in order to accurately estimate the dose to the extremities during manipulation of radioactive sources. We report the results of these simulations for 90Y, 131I, 18F and 111In nuclides in water solutions enclosed in glass or plastic receptacles, such as vials or syringes. Skin equivalent doses at 70 μm of depth and dose-depth profiles are reported for different configurations, highlighting the importance of adopting a realistic geometrical configuration in order to get accurate dosimetric estimations. Due to the easiness of implementation of GAMOS simulations, case-specific geometries and nuclides can be adopted and results can be obtained in less than about ten minutes of computation time with a common workstation.

  13. The effect of iodine uptake on radiation dose absorbed by patient tissues in contrast enhanced CT imaging. Implications for CT dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Perisinakis, Kostas; Damilakis, John [University of Crete, Department of Medical Physics, Medical School, Heraklion, Crete (Greece); University Hospital of Heraklion, Department of Medical Physics, Heraklion, Crete (Greece); Tzedakis, Antonis; Papadakis, Antonios E. [University Hospital of Heraklion, Department of Medical Physics, Heraklion, Crete (Greece); Spanakis, Kostas [University Hospital of Heraklion, Department of Radiology, Heraklion, Crete (Greece); Hatzidakis, Adam [University Hospital of Heraklion, Department of Radiology, Heraklion, Crete (Greece); University of Crete, Department of Radiology, Medical School, Heraklion, Crete (Greece)

    2018-01-15

    To investigate the effect of iodine uptake on tissue/organ absorbed doses from CT exposure and its implications in CT dosimetry. The contrast-induced CT number increase of several radiosensitive tissues was retrospectively determined in 120 CT examinations involving both non-enhanced and contrast-enhanced CT imaging. CT images of a phantom containing aqueous solutions of varying iodine concentration were obtained. Plots of the CT number increase against iodine concentration were produced. The clinically occurring iodine tissue uptake was quantified by attributing recorded CT number increase to a certain concentration of aqueous iodine solution. Clinically occurring iodine uptake was represented in mathematical anthropomorphic phantoms. Standard 120 kV CT exposures were simulated using Monte Carlo methods and resulting organ doses were derived for non-enhanced and iodine contrast-enhanced CT imaging. The mean iodine uptake range during contrast-enhanced CT imaging was found to be 0.02-0.46% w/w for the investigated tissues, while the maximum value recorded was 0.82% w/w. For the same CT exposure, iodinated tissues were found to receive higher radiation dose than non-iodinated tissues, with dose increase exceeding 100% for tissues with high iodine uptake. Administration of iodinated contrast medium considerably increases radiation dose to tissues from CT exposure. (orig.)

  14. 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)

  15. 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.

  16. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    Enrique

    between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from the source. The study included the interventional radiolo- gists, radiographers and nurses ...

  17. Calculation of absorbed dose around a facility for disposing of low activity natural radioactive waste (C3-dump)

    International Nuclear Information System (INIS)

    Jansen, J. T. M.; Zoetelief, J.

    2005-01-01

    A C3-dump is a facility for disposing of low activity natural radioactive waste containing the uranium series 238 U, the thorium series 232 Th and 40 K. Only the external radiation owing to gamma rays, X-rays and annihilation photons is considered in this study. For two situations - the semi-infinite slab and the tourist geometry - the conversion coefficients from specific activity to air kerma rate at 1 m above the relevant level are calculated. In the first situation the waste material is in contact with the air but in the tourist geometry it is covered with a 1.35 m thick layer. For the calculations, the Monte Carlo radiation transport code MCNP is used. The yield and photon energy for each radionuclide are according to the database of Oak Ridge National Laboratory. For the tourist situation, the depth-dose distribution through the covering layer is calculated and extrapolated to determine the exit dose. (authors)

  18. Radioiodine therapy in Graves' disease based on tissue-absorbed dose calculations: effect of pre-treatment thyroid volume on clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Michael J.; Joe, Alexius Y.; Mallek, Dirk von; Ezziddin, Samer; Palmedo, Holger [Department of Nuclear Medicine, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Brink, Ingo [Department of Nuclear Medicine, University Hospital of Freiburg (Germany); Krause, Thomas M. [Department of Nuclear Medicine, Inselspital Bern (Switzerland)

    2002-09-01

    This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15{+-}9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256{+-}80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses

  19. Development and comparison of computational models for estimation of absorbed organ radiation dose in rainbow trout (Oncorhynchus mykiss) from uptake of iodine-131

    International Nuclear Information System (INIS)

    Martinez, N.E.; Johnson, T.E.; Capello, K.; Pinder, J.E.

    2014-01-01

    This study develops and compares different, increasingly detailed anatomical phantoms for rainbow trout (Oncorhynchus mykiss) for the purpose of estimating organ absorbed radiation dose and dose rates from 131 I uptake in multiple organs. The models considered are: a simplistic geometry considering a single organ, a more specific geometry employing additional organs with anatomically relevant size and location, and voxel reconstruction of internal anatomy obtained from CT imaging (referred to as CSUTROUT). Dose Conversion Factors (DCFs) for whole body as well as selected organs of O. mykiss were computed using Monte Carlo modeling, and combined with estimated activity concentrations, to approximate dose rates and ultimately determine cumulative radiation dose (μGy) to selected organs after several half-lives of 131 I. The different computational models provided similar results, especially for source organs (less than 30% difference between estimated doses), and whole body DCFs for each model (∼3 × 10 −3 μGy d −1 per Bq kg −1 ) were comparable to DCFs listed in ICRP 108 for 131 I. The main benefit provided by the computational models developed here is the ability to accurately determine organ dose. A conservative mass-ratio approach may provide reasonable results for sufficiently large organs, but is only applicable to individual source organs. Although CSUTROUT is the more anatomically realistic phantom, it required much more resource dedication to develop and is less flexible than the stylized phantom for similar results. There may be instances where a detailed phantom such as CSUTROUT is appropriate, but generally the stylized phantom appears to be the best choice for an ideal balance between accuracy and resource requirements. - Highlights: • Computational models (phantoms) are developed for rainbow trout internal dosimetry. • Phantoms are combined with empirical models for 131 I uptake to estimate dose. • Voxel and stylized phantoms predict

  20. An assessment of absorbed dose and radiation hazard index from soil around repository facility at Bukit Kledang, Perak, Malaysia

    Science.gov (United States)

    Adziz, M. I. Abdul; Khoo, K. S.

    2018-01-01

    The process of natural decay of radionuclides that emit gamma rays can infect humans and other living things. In this study, soil samples were taken at various locations which have been identified around the Long Term Storage Facility (LTSF) in Bukit Kledang, Perak. In addition, the respective dose rates in the sampling sites were measured at 5cm and 1m above the ground using a survey meter with Geiger Muller (GM) detector. Soil samples were taken using a hand Auger and then brought back to the laboratory for sample prepreparation process. The measuring of radioactivity concentration in soil samples were carried out using gamma spectrometer counting system equipped with HPGe detector. The obtained results show, the radioactivity concentration ranged from 11.98 - 29.93 Bq/kg for Radium-226 (226Ra), 20.97 - 41.45 Bq/kg for Thorium-232 (232Th) and 5.73 - 59.41 Bq/kg for Potassium-40 (40K), with mean values of 20.83 ± 5.88 Bq/kg, 32.87 ± 5.88 Bq/kg and 21.50 ± 2.79 Bq/kg, respectively. To assess the radiological hazards of natural radioactivity, radium equivalent activity (Raeq), the rate of absorption dose (D), the annual effective dose and external hazard index (Hex) was calculated and compared to the world average values.

  1. Neutron relative biological effectiveness for solid cancer incidence in the Japanese A-bomb survivors: an analysis considering the degree of independent effects from γ-ray and neutron absorbed doses with hierarchical partitioning.

    Science.gov (United States)

    Walsh, Linda

    2013-03-01

    It has generally been assumed that the neutron and γ-ray absorbed doses in the data from the life span study (LSS) of the Japanese A-bomb survivors are too highly correlated for an independent separation of the all solid cancer risks due to neutrons and due to γ-rays. However, with the release of the most recent data for all solid cancer incidence and the increased statistical power over previous datasets, it is instructive to consider alternatives to the usual approaches. Simple excess relative risk (ERR) models for radiation-induced solid cancer incidence fitted to the LSS epidemiological data have been applied with neutron and γ-ray absorbed doses as separate explanatory covariables. A simple evaluation of the degree of independent effects from γ-ray and neutron absorbed doses on the all solid cancer risk with the hierarchical partitioning (HP) technique is presented here. The degree of multi-collinearity between the γ-ray and neutron absorbed doses has also been considered. The results show that, whereas the partial correlation between the neutron and γ-ray colon absorbed doses may be considered to be high at 0.74, this value is just below the level beyond which remedial action, such as adding the doses together, is usually recommended. The resulting variance inflation factor is 2.2. Applying HP indicates that just under half of the drop in deviance resulting from adding the γ-ray and neutron absorbed doses to the baseline risk model comes from the joint effects of the neutrons and γ-rays-leaving a substantial proportion of this deviance drop accounted for by individual effects of the neutrons and γ-rays. The average ERR/Gy γ-ray absorbed dose and the ERR/Gy neutron absorbed dose that have been obtained here directly for the first time, agree well with previous indirect estimates. The average relative biological effectiveness (RBE) of neutrons relative to γ-rays, calculated directly from fit parameters to the all solid cancer ERR model with both

  2. Whole-body biodistribution, radiation absorbed dose, and brain SPET imaging with [{sup 123}I]5-I-A-85380 in healthy human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Masahiro; Tamagnan, G.; Baldwin, R.M.; Khan, S.; Bozkurt, A. [Yale Univ., New Haven, CT (United States). School of Medicine; Seibyl, J.P.; Early, M. [Institute for Neurodegenerative Disorders, New Haven, CT (United States); Vaupel, B.D.; Horti, A.G.; Mukhin, A.G.; Kimes, A.S. [Brain Imaging Center, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD (United States); Zoghbi, S.S. [Yale Univ., New Haven, CT (United States). Dept. of Radiology; Koren, A.O.; London, E.D. [Brain Imaging Center, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD (United States); Departments of Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, CA (United States); Innis, R.B. [Molecular Imaging Branch, National Institutes of Mental Health (United States)

    2002-02-01

    The biodistribution of radioactivity after the administration of a new tracer for {alpha}4{beta}2 nicotinic acetylcholine receptors (nAChRs), [{sup 123}I]5-iodo-3-[2(S)-2-azetidinylmethoxy]pyridine (5-I-A-85380), was studied in ten healthy human subjects. Following administration of 98{+-}6 MBq [{sup 123}I]5-I-A-85380, serial whole-body images were acquired over 24 h and corrected for attenuation. One to four brain single-photon emission tomography (SPET) images were also acquired between 2.5 and 24 h. Estimates of radiation absorbed dose were calculated using MIRDOSE 3.1 with a dynamic bladder model and a dynamic gastrointestinal tract model. The estimates of the highest absorbed dose ({mu}Gy/MBq) were for the urinary bladder wall (71 and 140), lower large intestine wall (70 and 72), and upper large intestine wall (63 and 64), with 2.4-h and 4.8-h urine voiding intervals, respectively. The whole brain activity at the time of the initial whole-body imaging at 14 min was 5.0% of the injected dose. Consistent with the known distribution of {alpha}4{beta}2 nAChRs, SPET images showed the highest activity in the thalamus. These results suggest that [{sup 123}I]5-I-A-85380 is a promising SPET agent to image {alpha}4{beta}2 nAChRs in humans, with acceptable dosimetry and high brain uptake. (orig.)

  3. Differences in absorbed doses at risk organs and target tumoral of planning(PTV) in lung treatments using two algorithms of different calculations

    International Nuclear Information System (INIS)

    Uruena Llinares, A.; Santos Rubio, A.; Luis Simon, F. J.; Sanchez Carmona, G.; Herrador Cordoba, M.

    2006-01-01

    The objective of this paper is to compare, in thirty treatments for lung cancer,the absorbed doses at risk organs and target volumes obtained between the two used algorithms of calculation of our treatment planning system Oncentra Masterplan, that is, Pencil Beams vs Collapsed Cone. For it we use a set of measured indicators (D1 and D99 of tumor volume, V20 of lung, homogeneity index defined as (D5-D95)/D prescribed, and others). Analysing the dta, making a descriptor analysis of the results, and applying the non parametric test of the ranks with sign of Wilcoxon we find that the use of Pencil Beam algorithm underestimates the dose in the zone of the PTV including regions of low density as well as the values of maximum dose in spine cord. So, we conclude that in those treatments in which the spine dose is near the maximum permissible limit or those in which the PTV it includes a zone with pulmonary tissue must be used the Collapse Cone algorithm systematically and in any case an analysis must become to choose between time and precision in the calculation for both algorithms. (Authors)

  4. Tumoral fibrosis effect on the radiation absorbed dose of 177Lu-Tyr3-octreotate-gold nanoparticles and 177Lu-Tyr3-octreotate radiopharmaceuticals

    International Nuclear Information System (INIS)

    Zambrano R, O. D.

    2015-01-01

    In this work was comparatively evaluated the effect of tumoral fibrosis in the radiation absorbed dose of the radiopharmaceutical 177 Lu-Tyr 3 -octreotate with and without gold nanoparticles. For this, was used an experimental array of tumoral fibrosis and computer models based on Monte Carlo calculations to simulate tumoral micro environments without fibrosis and with fibrosis. The computer simulation code Penelope (Penetration Energy Loss of Positron and Electrons) and MCNP (Monte Carlo N-particle Transport Code System) which are based on the Monte Carlo methodology were used to create the computer models for the simulation of the transport of particles (emitted by 177 Lu) in the micro environments (without fibrosis and with fibrosis) with the purpose of calculating the radiation absorbed dose in the interstitial space and in the nucleus of cancer cells. The first computational model consisted of multiple concentric spheres (as onion shells) with the radioactive source homogeneously distributed in the shell between 5 and 10 μm in diameter which represents the internalization of the radioactive source into the cell cytoplasm as it occurs in target specific radiotherapy. The concentric spheres were useful to calculate the radiation absorbed dose in depth in the models without fibrosis and with fibrosis. Furthermore, there were constructed other computer models using two different codes that simulate the transport of radiation (Penelope and MCNP). These models consist of seven spheres that represent cancer cells (HeLa cells) of 10 μm in diameter and each one of them contain another smaller sphere in the center that represents the cell nucleus. A comparison was done of the radiation absorbed dose in the nucleus of the cells, calculated with both codes, Penelope and MCNP. The radioactive source ( 177 Lu) used for the simulations was given to the codes by means of a convoluted spectrum of the most important beta particles (high percentage emission). To this spectrum

  5. Comparison between Radiology Science Laboratory, Brazil (LCR) and National Research Council, Canada (NRC) of the absorbed dose in water using Fricke dosimetry; Comparacao entre o LCR/Brasil e o NRC/Canada da dose absorvida na agua usando a dosimetria Fricke

    Energy Technology Data Exchange (ETDEWEB)

    Salata, Camila; David, Mariano Gazineu; Almeida, Carlos Eduardo de [Universidade do Estado do Rio de Janeiro (UERJ/LCR), Rio de Janeiro (Brazil). Lab. de Ciencias Radiologicas; El Gamal, Islam; Cojocaru, Claudiu; Mainegra-Hing, Ernesto; McEwen, Malcom, E-mail: mila.salata@gmail.com [National Research Council, Ottawa (Canada)

    2014-07-01

    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)

  6. A comparison of analogue and digital techniques in upper gastrointestinal examinations: absorbed dose and diagnostic quality of the images

    International Nuclear Information System (INIS)

    Axelsson, B.; Hansson, I.B.; Boden, K.; Witt, H.H.; Fransson, S.G.; Persliden, J.

    2000-01-01

    This study was performed to investigate whether patient exposure and diagnostic quality of the image is significantly influenced by the introduction of digital image acquisition techniques. Evaluation was performed for three different techniques (analogue, analogue fluoro+digital radiography, digital) in examination of the upper gastrointestinal tract. The evaluation was done from data acquired in three different departments. Patient exposure was recorded as KERMA-area product (KAP) and the individual patient readings were normalised to a standard size patient. Image quality was assessed using visual grading with a reference image. The recorded KAP values were significantly higher (22.3 Gycm 2 ) for the fully digital technique compared to the others (analogue 6.8 Gycm 2 , analogue+digital 3.6 Gycm 2 ). This was due mostly to an increased number of exposures. The diagnostic quality of the image was, however, also regarded to be slightly lower for the technique giving the lowest patient dose with the smallest number of exposures (analogue+digital). The digital examination technique, as used in this study, thus resulted in significantly higher patient dose without any significant gain in diagnostic quality of the image. (orig.)

  7. Code intercomparison and benchmark for muon fluence and absorbed dose induced by an 18-GeV electron beam after massive iron shielding

    CERN Document Server

    Fassò, Alberto; Ferrari, Anna; Mokhov, Nikolai V.; Müller, Stefan E.; Nelson, Walter Ralph; Roesler, Stefan; Sanami, Toshiya; Striganov, Sergei I.; Versaci, Roberto

    2015-01-01

    In 1974, Nelson, Kase, and Svenson published an experimental investigation on muon shielding using the SLAC high energy LINAC. They measured muon fluence and absorbed dose induced by a 18 GeV electron beam hitting a copper/water beam dump and attenuated in a thick steel shielding. In their paper, they compared the results with the theoretical mode ls available at the time. In order to compare their experimental results with present model calculations, we use the modern transport Monte Carlo codes MARS15, FLUKA2011 and GEANT4 to model the experimental setup and run simulations. The results will then be compared between the codes, and with the SLAC data.

  8. Measurement of extrapolation curves for the secondary pattern of beta radiation Nr. 86 calibrated in rapidity of absorbed dose for tissue equivalent by the Physikalisch Technische Bundesanstalt

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1988-10-01

    The following report has as objective to present the obtained results of measuring - with a camera of extrapolation of variable electrodes (CE) - the dose speed absorbed in equivalent fabric given by the group of sources of the secondary pattern of radiation Beta Nr. 86, (PSB), and to compare this results with those presented by the calibration certificates that accompany the PSB extended by the primary laboratory Physikalisch Technische Bundesanstalt, (PTB), of the R.F.A. as well as the uncertainties associated to the measure process. (Author)

  9. Study of the effect of γ-absorbed dose on degradation of polypropylene/starch-filled polymer containing photo-initiators by spectroscopic methods

    Science.gov (United States)

    Bagheri, Rouhollah.

    2009-09-01

    γ irradiated samples containing photo-initiators (PIs) with and without corn starch at 0-60 kGy were studied by UV spectrophotometer and FTIR. A linear decrease in the wavelength of absorbance maximum of each aromatic PI is observed by increase in the dose. The presence of starch in the sample caused a fluctuation of the absorptions. An increase in carbonyl formation due to the effect of a PI was detected. Ferric stearate and Irgacure 184 showed the highest and lowest effect respectively.

  10. SU-F-19A-02: Comparison of Absorbed Dose to Water Standards for HDR Ir-192 Brachytherapy Between the LCR, Brazil and NRC, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Salata, C; David, M; Almeida, C de [Universidade do Estado do Rio de Janeiro, Rio De Janeiro, RJ (Brazil); El Gamal, I; Cojocaru, C; Mainegra-Hing, E; McEwen, M [National Research Council, Ottawa, ON (Canada)

    2014-06-15

    Purpose: To compare absorbed dose to water standards for HDR brachytherapy dosimetry developed by the Radiological Science Laboratory of Rio de Janeiro State University (LCR) and the National Research Council, Canada (NRC). Methods: The two institutions have separately developed absorbed dose standards based on the Fricke dosimetry system. There are important differences between the two standards, including: preparation and read-out of the Fricke solution, irradiation geometry of the Fricke holder in relation to the Ir-192 source, and determination of the G-value to be used at Ir-192 energies. All measurements for both standards were made directly at the NRC laboratory (i.e., no transfer instrument was used) using a single Ir-192 source (microSelectron v2). In addition, the NRC group has established a self-consistent method to determine the G-value for Ir-192, based on an interpolation between G-values obtained at Co-60 and 250kVp X-rays, and this measurement was repeated using the LCR Fricke solution to investigate possible systematic uncertainties. Results: G-values for Co-60 and 250 kVp x-rays, obtained using the LCR Fricke system, agreed with the NRC values within 0.5 % and 1 % respectively, indicating that the general assumption of universal G-values is appropriate in this case. The standard uncertainty in the determination of G for Ir-192 is estimated to be 0.6 %. For the comparison of absorbed dose measurements at the reference point for Ir-192 (1 cm depth in water, perpendicular to the seed long-axis), the ratio Dw(NRC)/Dw(LCR) was found to be 1.011 with a combined standard uncertainty of 1.7 %, k=1. Conclusion: The agreement in the absorbed dose to water values for the LCR and NRC systems is very encouraging. Combined with the lower uncertainty in this approach compared to the present air-kerma approach, these results reaffirm the use of Fricke solution as a potential primary standard for HDR Ir-192 brachytherapy.

  11. Update on the Code Intercomparison and Benchmark for Muon Fluence and Absorbed Dose Induced by an 18 GeV Electron Beam After Massive Iron Shielding

    Energy Technology Data Exchange (ETDEWEB)

    Fasso, A. [SLAC; Ferrari, A. [CERN; Ferrari, A. [HZDR, Dresden; Mokhov, N. V. [Fermilab; Mueller, S. E. [HZDR, Dresden; Nelson, W. R. [SLAC; Roesler, S. [CERN; Sanami, t.; Striganov, S. I. [Fermilab; Versaci, R. [Unlisted, CZ

    2016-12-01

    In 1974, Nelson, Kase and Svensson published an experimental investigation on muon shielding around SLAC high-energy electron accelerators [1]. They measured muon fluence and absorbed dose induced by 14 and 18 GeV electron beams hitting a copper/water beamdump and attenuated in a thick steel shielding. In their paper, they compared the results with the theoretical models available at that time. In order to compare their experimental results with present model calculations, we use the modern transport Monte Carlo codes MARS15, FLUKA2011 and GEANT4 to model the experimental setup and run simulations. The results are then compared between the codes, and with the SLAC data.

  12. Análise da distribuição espacial de dose absorvida em próton terapia ocular Spatial distribution analysis of absorbed dose in ocular proton radiation therapy

    Directory of Open Access Journals (Sweden)

    Marília Tavares Christóvão

    2010-08-01

    of proton therapy were performed based on preexisting facilities. RESULTS: Simulation data were integrated into SISCODES on the eye's model generating spatial dose distributions. Dose depth profiles reproducing the pure and modulated Bragg peaks are presented. Relevant aspects of proton beam radiotherapy planning are considered such as material absorber, modulation, collimator dimensions, incident proton energy and isodose generation. CONCLUSION: The conclusion is that proton therapy when properly modulated and directed can reproduce the ideal conditions for the dose deposition in the treatment of ocular tumors.

  13. Absorbed dose profiles for 32P, 90Y, 188Re, 177Lu, 51Cr, 153Sm and 169Er: radionuclides used in radiosynoviortheses treatment

    International Nuclear Information System (INIS)

    Torres, M.; Ayra, E.; Albuerne, O.; Delgado, M.

    2008-01-01

    The remarkable advances in the design and synthesis of radiopharmaceuticals has created the opportunity of generating new agents for the treatment of radiosynoviortheses (RSV) which exhibit a minimum leakage from the synovial joint reducing, this way, the non desired absorbed doses to non target organs such as liver, spleen, kidney. Nowadays, the variety of beta emitters used in RSV ranges between 0.34 MeV - 0.33 mm penetration in tissue ( 169 Er) and 2.27 MeV - 3.6 mm penetration in tissue ( 90 Y). The half life of these isotopes goes from 2.3 hours ( 165 Dy) to 27.8 days ( 51 Cr). The selection criterion on which radionuclide should be used, in modern clinics, depends on which joints are to be treated. Thus, the smaller the joint, the lowest should be the energy of the beta emitted and the penetration in soft tissue of these particles. This leads to the use of fixed radionuclides and doses for each kind of joint. In the Isotopes Centre, we've been carrying on studies for the development of radiopharmaceuticals for the radiosynoviortheses treatment and focused our attention in the following radionuclides: 32 P, 90 Y, 188 Re, 177 Lu, 51 Cr, 153 Sm and 169 Er. The main objective of this paper was to obtain the absorbed dose profiles for radionuclides of frequent or potential use in radiosynoviortheses. These profiles reveal the absorbed dose imparted per unit activity of injected radionuclide (Gy/h*MBq) in the synovial membrane and the articular cartilage. The researched radionuclides were those previously mentioned. Also were calculated the therapeutic range of each radionuclides in synovial tissue. The therapeutic range is defined as the deepness at which the absorbed dose equals the 10 % of the maximum dose deposited in the synovial surface. This range determines the synovial thickness that can be sufficiently irradiated and thus successfully treated. The synovial membrane model consisted on a cylinder with the source uniformly distributed in its volume. This

  14. Determination of the optimal statistical uncertainty to perform electron-beam Monte Carlo absorbed dose estimation in the target volume; Determination de l'incertitude statistique optimale pour realiser un calcul de dose dans le volume cible en utilisant la methode de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Isambert, A.; Lefkopoulos, D. [Institut Gustave-Roussy, Medical Physics Dept., 94 - Villejuif (France); Brualla, L. [NCTeam, Strahlenklinik, Universitatsklinikum Essen (Germany); Benkebil, M. [DOSIsoft, 94 - Cachan (France)

    2010-04-15

    Purpose of study Monte Carlo based treatment planning system are known to be more accurate than analytical methods for performing absorbed dose estimation, particularly in and near heterogeneities. However, the required computation time can still be an issue. The present study focused on the determination of the optimum statistical uncertainty in order to minimise computation time while keeping the reliability of the absorbed dose estimation in treatments planned with electron-beams. Materials and methods Three radiotherapy plans (medulloblastoma, breast and gynaecological) were used to investigate the influence of the statistical uncertainty of the absorbed dose on the target volume dose-volume histograms (spinal cord, intra-mammary nodes and pelvic lymph nodes, respectively). Results The study of the dose-volume histograms showed that for statistical uncertainty levels (1 S.D.) above 2 to 3%, the standard deviation of the mean dose in the target volume calculated from the dose-volume histograms increases by at least 6%, reflecting the gradual flattening of the dose-volume histograms. Conclusions This work suggests that, in clinical context, Monte Carlo based absorbed dose estimations should be performed with a maximum statistical uncertainty of 2 to 3%. (authors)

  15. Dose calculation for electrons

    International Nuclear Information System (INIS)

    Hirayama, Hideo

    1995-01-01

    The joint working group of ICRP/ICRU is advancing the works of reviewing the ICRP publication 51 by investigating the data related to radiation protection. In order to introduce the 1990 recommendation, it has been demanded to carry out calculation for neutrons, photons and electrons. As for electrons, EURADOS WG4 (Numerical Dosimetry) rearranged the data to be calculated at the meeting held in PTB Braunschweig in June, 1992, and the question and request were presented by Dr. J.L. Chartier, the responsible person, to the researchers who are likely to undertake electron transport Monte Carlo calculation. The author also has carried out the requested calculation as it was the good chance to do the mutual comparison among various computation codes regarding electron transport calculation. The content that the WG requested to calculate was the absorbed dose at depth d mm when parallel electron beam enters at angle α into flat plate phantoms of PMMA, water and ICRU4-element tissue, which were placed in vacuum. The calculation was carried out by the versatile electron-photon shower computation Monte Carlo code, EGS4. As the results, depth dose curves and the dependence of absorbed dose on electron energy, incident angle and material are reported. The subjects to be investigated are pointed out. (K.I.)

  16. The expression revealing variation trend about radiation resistance of aromatic polymers serving in nuclear environment over absorbed dose

    Science.gov (United States)

    Lu, Shuangying; Hu, Huasi; Hu, Guang; Liu, Bin

    2015-03-01

    For polymeric materials applied in nuclear environment, the macroscopic properties usually remain unchanged after irradiation for several years or decades up to a threshold dose at which the deterioration of materials begins to take place. In this paper, the general radiation response of aromatic polymers is firstly reviewed and discussed. Then percolation theory is employed innovatively to elucidate the critical phenomenon over the service life for polymeric materials with high radiation resistance. For a better quantitative evaluation, a novel two-parameter radiation resistance model is proposed by the method of analogy between two nuclear-related phenomena. Six epoxy systems are employed from the published literatures to verify the novel model and the result shows that it is reliable and helpful in not only estimating the radiation damage over the service period but also multi-objective optimum design of polymeric materials.

  17. Evaluation of the absorbed dose to the lungs due to Xe{sup 133} and Tc{sup 99m} (MAA); Evaluacion de la dosis absorbida en los pulmones debido al Xe{sup 133} y Tc{sup 99m} (MAA)

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez A, M.; Murillo C, F.; Castillo D, C.; Sifuentes D, Y.; Sanchez S, P. [Universidad Nacional de Trujillo, Av. Juan Pablo II s/n, Trujillo (Peru); Rojas P, E. [Instituto Peruano de Energia Nuclear, Av. Canada 1470, Lima (Peru); Marquez P, F., E-mail: marvva@hotmail.com [Instituto Nacional de Enfermedades Neoplasicas, Av. Angamos 2520, Lima (Peru)

    2015-10-15

    The absorbed dose in lungs of an adult patient has been evaluated using the biokinetics of radiopharmaceuticals containing Xe{sup 133} or Tc{sup 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 {sup 133}Xe is 0.00104 mGy/MBq. Here, the absorbed dose due to remaining tissue, included in the {sup 133}Xe biokinetics is not significant. The absorbed dose in the lungs, due Tc{sup 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{sup 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)

  18. Calibration of GafChromic EBT3 for absorbed dose measurements in 5 MeV proton beam and 60Co γ-rays

    International Nuclear Information System (INIS)

    Vadrucci, M.; Ronsivalle, C.; Marracino, F.; Montereali, R. M.; Picardi, L.; Piccinini, M.; Vincenti, M. A.; Esposito, G.; De Angelis, C.; Cherubini, R.; Pimpinella, M.

    2015-01-01

    Purpose: To study EBT3 GafChromic film in low-energy protons, and for comparison purposes, in a reference 60 Co beam in order to use it as a calibrated dosimetry system in the proton irradiation facility under construction within the framework of the Oncological Therapy with Protons (TOP)-Intensity Modulated Proton Linear Accelerator for RadioTherapy (IMPLART) Project at ENEA-Frascati, Italy. Methods: EBT3 film samples were irradiated at the Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Legnaro, Italy, with a 5 MeV proton beam generated by a 7 MV Van de Graaff CN accelerator. The nominal dose rates used were 2.1 Gy/min and 40 Gy/min. The delivered dose was determined by measuring the particle fluence and the energy spectrum in air with silicon surface barrier detector monitors. A preliminary study of the EBT3 film beam quality dependence in low-energy protons was conducted by passively degrading the beam energy. EBT3 films were also irradiated at ENEA-National Institute of Ionizing Radiation Metrology with gamma radiation produced by a 60 Co source characterized by an absorbed dose to water rate of 0.26 Gy/min as measured by a calibrated Farmer type ionization chamber. EBT3 film calibration curves were determined by means of a set of 40 film pieces irradiated to various doses ranging from 0.5 Gy to 30 Gy absorbed dose to water. An EPSON Expression 11000XL color scanner in transmission mode was used for film analysis. Scanner response stability, intrafilm uniformity, and interfilm reproducibility were verified. Optical absorption spectra measurements were performed on unirradiated and irradiated EBT3 films to choose the most sensitive color channel to the dose range used. Results: EBT3 GafChromic films show an under response up to about 33% for low-energy protons with respect to 60 Co gamma radiation, which is consistent with the linear energy transfer dependence already observed with higher energy protons, and a negligible dose-rate dependence in

  19. Contribution to the measurement of β absorbed dose. Attempt for interpreting the main anomalies in the operation of a variable cavity chamber and methodological consequences

    International Nuclear Information System (INIS)

    Hillion, Philippe.

    1976-11-01

    The absorbed dose characterization of primary reference beta sources necessitates the use of a particular ionization chamber: the variable-cavity chamber, or extrapolation chamber. On account of the β particles energy distributions, such an instrument must satisfy to precise physical constraints, concerning the definition of the collecting volume as well as the composition of the constituting materials of the chamber. This kind of dosimeter presents however certains anomalies due to polarization phenomena, resulting from the stopping of β particles in insulators and in the collecting electrode. This last effect produces a direct polarization current which adds to the ionization current and whose value is a function of cavity size and applied voltage. After analysis of the behavior of the different charge-carriers present inside the cavity, when a voltage is applied, a working model is proposed to explain the variation of the direct polarization current, and so, to allow a more precise determination of the ionization current. After presenting the variable-cavity chamber constructed at the Laboratoire de Metrologie des Rayonnements Ionisants, the different steps are described for obtaining, from the collected information, the absorbed dose in a given material under fixed conditions. The numerical data presented concern the characterization of a 90 Sr+ 90 Y reference source [fr

  20. Comparison of the calculated absorbed dose using the Cadplan™ treatment planning software and Tld-100 measurements in an Alderson-Rando phantom for a bronchogenic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez Castillo, J. G., E-mail: jggc59@hotmail.com [Departamento de Física, Hospital de Oncología, IMSS, CMN Siglo XXI, Cuauhtémoc 330 Col. Doctores (Mexico); Álvarez Romero, J. T., E-mail: trinidad.alvarez@inin.gob.mx, E-mail: fisarmandotorres@gmail.com, E-mail: victor.tovar@inin.gob.mx; Calderón, A. Torres, E-mail: trinidad.alvarez@inin.gob.mx, E-mail: fisarmandotorres@gmail.com, E-mail: victor.tovar@inin.gob.mx; M, V. Tovar, E-mail: trinidad.alvarez@inin.gob.mx, E-mail: fisarmandotorres@gmail.com, E-mail: victor.tovar@inin.gob.mx [SSDL, Departamento de Metrología ININ, Salazar, Estado de México 15245 (Mexico)

    2014-11-07

    To verify the accuracy of the absorbed doses D calculated by a TPS Cadplan for a bronchogenic treatment (in an Alderson-Rando phantom) are chosen ten points with the following D's and localizations. Point 1, posterior position on the left edge with 136.4 Gy. Points: 2, 3 and 4 in the left lung with 104.9, 104.3 and 105.8 Gy, respectively; points 5 and 6 at the mediastinum with 192.4 and 173.5 Gy; points 7, 8 and 9 in the right lung with 105.8, 104.2 and 104.7 Gy, and 10 at posterior position on right edge with 143.7 Gy. IAEA type capsules with TLD 100 powder are placed, planned and irradiated. The evaluation of the absorbed dose is carried out a curve of calibration for the LiF response (nC) {sup vs} {sup DW}, to several cavity theories. The traceability for the DW is obtained with a secondary standard calibrated at the NRC (Canada). The dosimetric properties for the materials considered are determined from the Hounsfield numbers reported by the TPS. The stopping power ratios are calculated for nominal spectrum to 6 MV photons. The percent variations among the planned and determined D in all the cases they are < ± 3%.

  1. 3D absorbed dose calculation with GATE Monte Carlo simulation for the image-guided radiation therapy dedicated to the small animal

    International Nuclear Information System (INIS)

    Noblet, Caroline

    2014-01-01

    Innovating irradiators dedicated to small animal allow to mimic clinical treatments in image-guided radiation therapy. Clinical practice is scaled down to the small animal by reducing beam dimensions (from cm to mm) and energy (from MeV to keV). Millimeter medium energy beams (<300 keV) are used to treat animals. This scaling induces higher constraints than in clinical practice especially for absorbed dose calculation in animals. Due to the beam dimensions and the medium energy range, clinical dose calculation methods are not easily applicable to the preclinical practice. Monte Carlo methods are needed. To this aim, a Monte Carlo model of the XRAD225Cx preclinical irradiator has been developed with the GATE (Geant4) framework. This model was validated by comparing simulation results against measurements and results obtained with a reference Monte Carlo code in external beam radiation therapy, EGSnrc. A specific issue has been highlighted: the significant dosimetric impact of tissue segmentation in the animal CT images. Indeed, at medium energy range, thresholding based on electronic density cannot accurately take into account the heterogeneities. Materials should be defined using both the tissue elemental composition and the mass density. An original segmentation method has been developed to obtain realistic dose distributions in small animals. Finally, our Monte Carlo platform has been successfully used for several radiobiological studies with mice and rats. (author) [fr

  2. Developing the Adult Male ICRP Phantom and Evaluation the Absorbed Dose Received By Critical Organs in Head and Neck Region during the Radiotherapy of Eye Cancer

    Directory of Open Access Journals (Sweden)

    Alireza Vejdani-Noghreiyan

    2016-09-01

    Full Text Available Introduction Accurate estimation of the absorbed dose in radiosensitive organs, located away from the target volume during radiotherapy, is one of the main reasons for the development of reference phantoms. The International Commission on Radiological Protection (ICRP reference phantoms can provide a more realistic view of the human anatomy in comparison with the previously used mathematical phantoms. However, the ICRP reference phantoms seem to have certain limitations, resulting in the inaccurate eye simulation due to the absence of super-high-resolution CT scan images. Materials and Methods In this study, we developed a modified version of the ICRP reference phantom by inserting a realistic eye phantom into the voxelized phantom. In addition, by using the developed model, the absorbed dose received by sensitive organs (e.g., thyroid, brain, and different parts of the eye during radiotherapy of a common ocular surface tumor was determined. The results were compared with those obtained by the modified phantom developed by the University of Florida-Oak Ridge National Laboratory (UF-ORNL. Results Based on the results, the relative difference between the equivalent doses calculated by the developed phantom and UF-ORNL phantom was nearly 75-95% and 3% for thyroid and eye substructures, respectively. Conclusion Despite of many advantageous of voxel phantoms, they have considerable limitation in providing accurate model of the eye. In the present study, a detailed stylized model was developed and incorporated into the Adult Male (AM reference and UF-ORNL phantoms. These phantoms were then used for the dosimetric calculations during eyelid cancer therapy.

  3. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

    Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

    2005-01-01

    With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

  4. Development of a diamond dosimeter for measuring the absorbed dose in small beams used in stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Marsolat, F.

    2014-01-01

    Stereotactic radiotherapy is a relatively recent technique used for the treatment of small benign and malignant tumors with small radiation beams. The clinical efficiency of this technique has been proved. However, the measurement of absolute and relative dose in small beams is not possible currently due to the lack of suited detectors for these measurements. In small beam dosimetry, the detector has to be as close as possible to tissue equivalence and exhibit a small detection volume due to the lack of lateral electronic equilibrium. Characteristics of diamond (water equivalent material Z=6, high density) make it an ideal candidate to fulfil most of small beam dosimetry requirements. In this thesis, we developed a dosimeter prototype for small beams, based on CVD synthetic single crystal diamond. The diamond samples were characterized optically and their detection properties were investigated under X-rays and alpha-particles. First diamond dosimeter prototypes were tested with small beams produced by several stereotactic machines. Studies using Monte Carlo simulations were performed in order to optimize the parameters involved in the detector response in small beams. This leaded to a final diamond dosimeter prototype that respects all radiotherapy centers requirements, in both standard and small beams. (author) [fr

  5. The use of solar cells for continuous recording of absorbed dose in the product during radiation sterilization

    International Nuclear Information System (INIS)

    Moehlmann, J.H.F.

    1981-01-01

    As a result of the rapidly developing space programme, reliable solar panels were needed as an energy source for space capsules. It was found that when a space capsule passed through the Van Allen Belt, the solar panels aged owing to the radiation, and the energy output declined. The United States National Aeronautics and Space Administration investigated the pre-irradiation of solar panels and found that they withstood high doses, such as 20 Mrad, the panels having aged and the energy output having become lower but steady. The response of the solar cells to high levels of radiation caused Gammaster to attempt to use this effect to serve as a check on the operating status of its large 60 Co gamma irradiation facility. During γ-irradiation a potential is generated in a p-n silicon solar cell which can be made to drive ancillary equipment. For example, the current from the solar cell can be fed to a pen recorder to assist in process control. The pen recorder can, for example, also act as an automatic logbook by recording the irradiation times. The sensitivity of a cell is such that changes in absorption between homogeneously and inhomogeneously filled containers are clearly shown on the recorder sheets. All source movements are visible, and the timer setting and the number of containers treated, etc. can be monitored. Such a system provides a reliable additional process control at low cost and requests little maintenance. (author)

  6. Concept of isoeffective doses in radiotherapy

    International Nuclear Information System (INIS)

    Ryabukhin, Yu.S.; Chekhonadskij, V.N.; Sushchikhina, M.A.

    1987-01-01

    The authors proposed the use of absorbed doses in standard regimens of irradiation to illustrate end-effects of unconventional variations of radiotherapy. They proposed that such doses should be defined as ''biological isoeffective doses under standard conditions of radiotherapy'' or, in short, ''standard isoeffective doses''. Three standard regimens of irradiation were described: separately for β-beam, for continuous interstitial and fractional intracavitary radiotherapy. It was proposed that a standard isoeffective dose value should be expressed in ''isogray'' abbreviated as (i) Gy

  7. The influence of saliva flow stimulation on the absorbed radiation dose to the salivary glands during radioiodine therapy of thyroid cancer using 124I PET(/CT) imaging.

    Science.gov (United States)

    Jentzen, Walter; Balschuweit, Dorothee; Schmitz, Jochen; Freudenberg, Lutz; Eising, Ernst; Hilbel, Thomas; Bockisch, Andreas; Stahl, Alexander

    2010-12-01

    A serious side effect of high-activity radioiodine therapy in the treatment of differentiated thyroid cancer is radiogenic salivary gland damage. This damage may be diminished by lemon-juice-induced saliva flow immediately after 131I administration. The aim of this study was to assess the effect of chewing lemon slices on the absorbed (radiation) doses to the salivary glands. Ten patients received (pretherapy) 124I PET(/CT) dosimetry before their first radioiodine therapy. The patients underwent a series of six PET scans at 0.5, 1, 2, 4, 48 and ≥96 h and one PET/CT scan at 24 h after administration of 27 MBq 124I. Blood samples were also collected at about 2, 4, 24, 48, and 96 h. Contrary to the standard radioiodine therapy protocol, the patients were not stimulated with lemon juice. Specifically, the patients chewed no lemon slices during the pretherapy procedure and neither ate food nor drank fluids until after completion of the last PET scan on the first day. Organ absorbed doses per administered 131I activity (ODpAs) as well as gland and blood uptake curves were determined and compared with published data from a control patient group, i.e. stimulated per the standard radioiodine therapy protocol. The calculations for both groups used the same methodology. A within-group comparison showed that the mean ODpA for the submandibular glands was not significantly different from that for the parotid glands. An intergroup comparison showed that the mean ODpA in the nonstimulation group averaged over both gland types was reduced by 28% compared to the mean ODpA in the stimulation group (p=0.01). Within each gland type, the mean ODpA reductions in the nonstimulation group were statistically significant for the parotid glands (p=0.03) but not for the submandibular glands (p=0.23). The observed ODpAs were higher in the stimulation group because of increased initial gland uptake rather than group differences in blood kinetics. The 124I PET(/CT) salivary gland dosimetry

  8. Estimation of organ cumulated activities and absorbed doses on intakes of several {sup 11}C labelled radiopharmaceuticals from external measurement with thermoluminescent dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takashi; Hayashi, Yoshiharu; Watabe, Hiroshi; Matsumoto, Masaki; Horikawa, Tohru; Fujiwara, Takehiko; Ito, Masatoshi; Yanai, Kazuhiko [Cyclotron and Radioisotope Center, Tohoku University, Aoba, Aramaki, Sendai 980-77 (Japan)

    1998-02-01

    We have developed a method for obtaining the cumulated activities in organs from radionuclides, which are injected into the patient in nuclear medicine procedures, by external exposure measurement with thermoluminescent dosimeters (TLDs) which are attached to the patient's body surface close to source organs to obtain information on body-surface doses. As the surface dose is connected to the cumulated activities in source organs through radiation transmission in the human body which can be estimated with the aid of a mathematical phantom, the organ cumulated activities can be obtained by the inverse transform method. The accuracy of this method was investigated by using a water phantom in which several gamma-ray volume sources of known activity were placed to simulate source organs. We then estimated by external measurements the organ cumulated activities and absorbed doses in subjects to whom the radiopharmaceuticals {sup 11}C-labelled Doxepin, {sup 11}C-labelled YM09151-2 and {sup 11}C-labelled Benzotropin were administered in clinical nuclear medicine procedures. The cumulated activities in the brain obtained with TLDs for Doxepin and YM09151-2 are 63.6{+-}6.2 and 32.1{+-}12.0 kBq h MBq{sup -1} respectively, which are compared with the respective values of 33.3{+-}9.9 and 23.9{+-}6.2 kBq h MBq{sup -1} with direct PET (positron emission tomography) measurements. The agreement between the two methods is within a factor of two. The effective doses of Doxepin, YM09151-2 and Benzotropin are determined as 6.92x10{sup -3}, 7.08x10{sup -3} and 7.65x10{sup -3} mSv MBq{sup -1} respectively with the TLD method. This method has great advantages, in that cumulated activities in several organs can be obtained easily with a single procedure, and the measurements of body surface doses are performed simultaneously with the nuclear medicine procedure, as TLDs are too small to interfere with other medical measurements. (author)

  9. 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)

  10. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Green, Patrick

    1992-01-01

    There is confusion over radiation dose limits between the International Commission on Radiological Protection, the National Radiological Protection Board and the Ministry of Agriculture, Fisheries and Food (MAFF), reports a Friends of the Earth's radiation campaigner. MAFF is suggesting the inadequate ICRP public dose limit does not apply to public exposures which arise from environmental contamination from past radioactive discharges. (author)

  11. Absorbed doses profiles vs Synovia tissue depth for the Y-90 and P-32 used in radiosynoviortesis treatment; Perfiles de dosis absorbida vs profundidad de tejido sinovial para el Y-90 y el P-32 empleados en tratamiento de radiosinoviortesis

    Energy Technology Data Exchange (ETDEWEB)

    Torres B, M.B.; Ayra P, F.E. [Centro de Isotopos (Cuba); Garcia R, E. [Hospital General Docente Enrique Cabrera (Cuba); Cornejo D, N. [CPHR, (Cuba); Yoriyaz, H. [IPEN, (Brazil)]. e-mail: nestor@cphr.edu.cu

    2006-07-01

    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{sup 2} to 250 cm{sup 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)

  12. 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

  13. Adaptation of penelope Monte Carlo code system to the absorbed dose metrology: characterization of high energy photon beams and calculations of reference dosimeter correction factors

    International Nuclear Information System (INIS)

    Mazurier, J.

    1999-01-01

    This thesis has been performed in the framework of national reference setting-up for absorbed dose in water and high energy photon beam provided with the SATURNE-43 medical accelerator of the BNM-LPRI (acronym for National Bureau of Metrology and Primary standard laboratory of ionising radiation). The aim of this work has been to develop and validate different user codes, based on PENELOPE Monte Carlo code system, to determine the photon beam characteristics and calculate the correction factors of reference dosimeters such as Fricke dosimeters and graphite calorimeter. In the first step, the developed user codes have permitted the influence study of different components constituting the irradiation head. Variance reduction techniques have been used to reduce the calculation time. The phase space has been calculated for 6, 12 and 25 MV at the output surface level of the accelerator head, then used for calculating energy spectra and dose distributions in the reference water phantom. Results obtained have been compared with experimental measurements. The second step has been devoted to develop an user code allowing calculation correction factors associated with both BNM-LPRI's graphite and Fricke dosimeters thanks to a correlated sampling method starting with energy spectra obtained in the first step. Then the calculated correction factors have been compared with experimental and calculated results obtained with the Monte Carlo EGS4 code system. The good agreement, between experimental and calculated results, leads to validate simulations performed with the PENELOPE code system. (author)

  14. Verification of absorbed doses determined with thimble and plane-parallel ionization chambers in clinical electron beams using ferrous sulphate dosimetry

    International Nuclear Information System (INIS)

    Thierens, H.

    1992-09-01

    Different ionometric methods to determine absorbed dose in phantoms irradiated with electron beams were tested using ferrous sulphate dosimetry as a reference method. Irradiation was carried out with three different types of accelerators in the energy range 4 to 20 MeV. Three different types of plane parallel ionization chambers were used and two types of cylindrical chambers. It was found that the ionization chamber dosimetry following the International Code of Practice (TRS 277) gave dose values as a mean 0.6% higher than the ferrous sulphate dosimetry based on the ICRU report 35. There were no significant differences between results measured at different electron energies. The mean deviation obtained using the two dosimeter systems is inside the experimental uncertainty. This proves that the TRS 277 can be used for accurate dosimetry. Further, the results show that corrections are needed for some types of plane parallel plate chambers to correct for the perturbation by the chamber of the electron fluence in the water phantom, and that values of these corrections are given as a function of the electron energy. 14 refs, 4 figs, 2 tabs

  15. Dose from radiological examinations

    International Nuclear Information System (INIS)

    Imamura, Keiko; Uji, Teruyuki; Sakuyama, Keiko; Fujikawa, Mitsuhiro; Fujii, Masamichi

    1976-01-01

    Relatively high gonad doses, several hundred to one thousand mR, have been observed in case of pelvis, hip-joint, coccyx, lower abdomen and lumber examination. Dose to the ovary is especially high in barium enema and I.V.P. examinations. About 12 per cent of the 4-ray examination are high-dose. The gonad dose is relatively high in examination of abdomen and lower extremities, in infants. The dose to the eyes is especially high, 1.0 to 2.5R per exposure, in temporal bone and nasal sinuses tomography. X-ray doses have been compared with dose limits recommended by ICRP and with the gonad dose from natural radiations. The gonad dose in lumbar examination, barium enema, I.V.P. etc. is as high as the maximum permissible dose per year recommended by ICRP. Several devices have been made for dose reduction in the daily examinations: (1) separating the radiation field from the gonad by one centimeter decreases the gonad dose about one-half. (2) using sensitive screens and films. In pelvimetry and in infant hip-joint examination, the most sensitive screen and film are used. In the I.V.P. examination of adult, use of MS screen in place of FS screen decreases the dose to one-third, i