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Sample records for peripheral dose measurement

  1. Entrance and peripheral dose measurements during radiotherapy

    International Nuclear Information System (INIS)

    Sulieman, A.; Kappas, K.; Theodorou, K.

    2008-01-01

    In vivo dosimetry of entrance dose was performed using thermoluminescent dosimeters (TLD) in order to evaluate the clinical application of the build up caps in patient dose measurements and for different treatment techniques. Peripheral dose (thyroid and skin) was measured for patients during breast radiotherapy to evaluate the probability of secondary cancer induction. TLD-100 chips were used with different Copper build up caps (for 6 MV and 15 MV photon beams from two linear accelerators. Entrance doses were measured for patients during radiotherapy course for breast, head and neck, abdomen and pelvis malignancies. The measured entrance dose for the different patients for 6 MV beams is found to be within the ±2.6% compared to the dose derived from theoretical estimation (normalized dose at D max ). The same measurements for 15 MV beams are found to be ±3 %. The perturbation value can reach up to 20% of the D max , which acts as a limitation for entrance dose measurements. An average thyroid skin dose of 3.7% of the prescribed dose was measured per treatment session while the mean skin dose breast treatment session is estimated to be 42% of D max , for both internal and external fields. These results are comparable in those of the in vivo of reported in literature. The risk of fatality due to thyroid cancer per treatment course is 3x10 -3

  2. Peripheral dose measurement for CyberKnife radiosurgery with upgraded linac shielding

    International Nuclear Information System (INIS)

    Chuang, Cynthia F.; Larson, David A.; Zytkovicz, Andrea; Smith, Vernon; Petti, Paula L.

    2008-01-01

    The authors investigated the peripheral dose reduction for CyberKnife radiosurgery treatments after the installation of a linac shielding upgrade. As in a previous investigation, the authors considered two treatment plans, one for a hypothetical target in the brain and another for a target in the thorax, delivered to an anthropomorphic phantom. The results of the prior investigation showed that the CyberKnife delivered significantly higher peripheral doses than comparable model C Gamma Knife or IMRT treatments. Current measurements, after the linac shielding upgrade, demonstrate that the additional shielding decreased the peripheral dose, expressed as a percentage of the delivered monitor units (MU), by a maximum of 59%. The dose reduction was greatest for cranial-caudal distances from the field edge less than 30 cm, and at these distances, the CyberKnife peripheral dose, expressed as a percentage of the delivered MU, is now comparable to that measured for the other treatment modalities in our previous investigation. For distances between 30 and 70 cm from the field edge, the additional shielding reduced the peripheral dose by between 20% and 55%. At these distances, the CyberKnife peripheral dose remains higher than doses measured in our previous study for the model C Gamma Knife and IMRT

  3. Measurement of off-axis and peripheral skin dose using radiochromic film

    International Nuclear Information System (INIS)

    Butson, Martin J.; Yu, P.K.N.; Metcalfe, P.E.

    1998-01-01

    A radiotherapy skin dose profile can be obtained with radiochromic film. The central axis skin dose relative to D max for a 10x10cm 2 field size was found to be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose increased with increasing field size. At 10 MV the skin dose 2 cm outside the geometric field edge was measured as 6%, 10% and 17% for 10x10cm 2 , 20x20cm 2 and 30x30cm 2 field sizes respectively. Off-axis skin dose decreased as distance increased from central axis for fields with Perspex block trays. For a 20x20cm 2 field, an approximately 5-8% drop in percentage skin dose was observed from central axis to the beam edge. (author)

  4. Peripheral doses from pediatric IMRT

    International Nuclear Information System (INIS)

    Klein, Eric E.; Maserang, Beth; Wood, Roy; Mansur, David

    2006-01-01

    Peripheral dose (PD) data exist for conventional fields (≥10 cm) and intensity-modulated radiotherapy (IMRT) delivery to standard adult-sized phantoms. Pediatric peripheral dose reports are limited to conventional therapy and are model based. Our goal was to ascertain whether data acquired from full phantom studies and/or pediatric models, with IMRT treatment times, could predict Organ at Risk (OAR) dose for pediatric IMRT. As monitor units (MUs) are greater for IMRT, it is expected IMRT PD will be higher; potentially compounded by decreased patient size (absorption). Baseline slab phantom peripheral dose measurements were conducted for very small field sizes (from 2 to 10 cm). Data were collected at distances ranging from 5 to 72 cm away from the field edges. Collimation was either with the collimating jaws or the multileaf collimator (MLC) oriented either perpendicular or along the peripheral dose measurement plane. For the clinical tests, five patients with intracranial or base of skull lesions were chosen. IMRT and conventional three-dimensional (3D) plans for the same patient/target/dose (180 cGy), were optimized without limitation to the number of fields or wedge use. Six MV, 120-leaf MLC Varian axial beams were used. A phantom mimicking a 3-year-old was configured per Center for Disease Control data. Micro (0.125 cc) and cylindrical (0.6 cc) ionization chambers were appropriated for the thyroid, breast, ovaries, and testes. The PD was recorded by electrometers set to the 10 -10 scale. Each system set was uniquely calibrated. For the slab phantom studies, close peripheral points were found to have a higher dose for low energy and larger field size and when MLC was not deployed. For points more distant from the field edge, the PD was higher for high-energy beams. MLC orientation was found to be inconsequential for the small fields tested. The thyroid dose was lower for IMRT delivery than that predicted for conventional (ratio of IMRT/cnventional ranged from

  5. Peripheral dose measurement in high-energy photon radiotherapy with the implementation of MOSFET.

    Science.gov (United States)

    Vlachopoulou, Vassiliki; Malatara, Georgia; Delis, Harry; Theodorou, Kiki; Kardamakis, Dimitrios; Panayiotakis, George

    2010-11-28

    To study the peripheral dose (PD) from high-energy photon beams in radiotherapy using the metal oxide semiconductor field effect transistor (MOSFET) dose verification system. The radiation dose absorbed by the MOSFET detector was calculated taking into account the manufacturer's Correction Factor, the Calibration Factor and the threshold voltage shift. PD measurements were carried out for three different field sizes (5 cm × 5 cm, 10 cm × 10 cm and 15 cm × 15 cm) and for various depths with the source to surface distance set at 100 cm. Dose measurements were realized on the central axis and then at distances (1 to 18 cm) parallel to the edge of the field, and were expressed as the percentage PD (% PD) with respect to the maximum dose (d(max)). The accuracy of the results was evaluated with respect to a calibrated 0.3 cm(3) ionization chamber. The reproducibility was expressed in terms of standard deviation (s) and coefficient of variation. % PD is higher near the phantom surface and drops to a minimum at the depth of d(max), and then tends to become constant with depth. Internal scatter radiation is the predominant source of PD and the depth dependence is determined by the attenuation of the primary photons. Closer to the field edge, where internal scatter from the phantom dominates, the % PD increases with depth because the ratio of the scatter to primary increases with depth. A few centimeters away from the field, where collimator scatter and leakage dominate, the % PD decreases with depth, due to attenuation by the water. The % PD decreases almost exponentially with the increase of distance from the field edge. The decrease of the % PD is more than 60% and can reach up to 90% as the measurement point departs from the edge of the field. For a given distance, the % PD is significantly higher for larger field sizes, due to the increase of the scattering volume. Finally, the measured PD obtained with MOSFET is higher than that obtained with an ionization chamber

  6. Peripheral dose outside applicators in electron beams

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    The peripheral dose outside the applicators in electron beams was studied using a Varian 21 EX linear accelerator. To measure the peripheral dose profiles and point doses for the applicator, a solid water phantom was used with calibrated Kodak TL films. Peak dose spot was observed in the 4 MeV beam outside the applicator. The peripheral dose peak was very small in the 6 MeV beam and was ignorable at higher energies. Using the 10 x 10 cm 2 cutout and applicator, the dose peak for the 4 MeV beam was about 12 cm away from the field central beam axis (CAX) and the peripheral dose profiles did not change with depths measured at 0.2, 0.5 and 1 cm. The peripheral doses and profiles were further measured by varying the angle of obliquity, cutout and applicator size for the 4 MeV beam. The local peak dose was increased with about 3% per degree angle of obliquity, and was about 1% of the prescribed dose (angle of obliquity equals zero) at 1 cm depth in the phantom using the 10 x 10 cm 2 cutout and applicator. The peak dose position was also shifted 7 mm towards the CAX when the angle of obliquity was increased from 0 to 15 deg. (note)

  7. Peripheral doses of cranial pediatric IMRT performed with attenuator blocks

    International Nuclear Information System (INIS)

    Soboll, Danyel Scheidegger; Schitz, Ivette; Schelin, Hugo Reuters; Silva, Ricardo Goulart da; Viamonte, Alfredo

    2011-01-01

    This paper presents values of peripheral doses measured at six vital points of simulator objects which represent the ages of 2, 5 and 10 years old, submitted to a cranial IMRT procedure that applied compensator blocks interposed to 6 MV beams. The found values indicate that there is independence of dose with position of measurements and age of the patient, as the peripheral dose at the points nearest and the 2 year old simulator object where larger. The doses in thyroid reached the range of 1.4 to 2.9% of the dose prescribed in the isocenter, indicating that the peripheral doses for IMRT that employ compensator blocks can be greater than for the IMRT produced with sliding window technique

  8. Measurement of the photon and neutron dose in peripheral IMRT treatments in adult mannequin, adolescent and child

    International Nuclear Information System (INIS)

    Sansaloni, F.; Lagares, J. L.; Exposito, M. R.; Terron, J. A.; Nunez, L.; Barquero, R.; Sanchez-Doblado, F.

    2011-01-01

    In this study we have performed measurements at different points of interest with polyethylene anthropomorphic dummies, which we call NORMA for three different patient sizes: adult, adolescent and child.

  9. Peripheral dose in photon beams from a linear accelerator with a multileaf collimator

    International Nuclear Information System (INIS)

    Lope Lope, R.; Lozano Flores, F.; Gracia Sorrosal, J.; Font Gomez, J.A.; Hernandez Vitoria, A.

    2001-01-01

    Radiation doses outside the radiotherapy treatment field are of radiation protection interest when anatomical structures with very low dose tolerances might be involved. One of the major sources of peripheral dose, scatter from secondary collimators, depends on the configuration of the collimator. In this study, peripheral dose was measured at two depths for 6 and 18 MV photons from a linac Primus (Siemens) with a multileaf collimator (MLC). Comparative measurements were made both with leaves and with the upper jaw positioned at the field edge near to the detector. Configuring the MLC leaves at the field edge yielded a reduction in peripheral dose. (author)

  10. Peripheral dose measurements with diode and thermoluminescence dosimeters for intensity modulated radiotherapy delivered with conventional and un-conventional linear accelerator

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh; Tambe, Chandrashekhar; Kadam, Sudarshan; Deshpande, Deepak; Gamre, Poonam; Biju, George; Suryaprakash; Magai, C.S.; Shrivastava, Shyam; Dhote, Dipak

    2013-01-01

    The objective of this paper was to measure the peripheral dose (PD) with diode and thermoluminescence dosimeter (TLD) for intensity modulated radiotherapy (IMRT) with linear accelerator (conventional LINAC), and tomotherapy (novel LINAC). Ten patients each were selected from Trilogy dual-energy and from Hi-Art II tomotherapy. Two diodes were kept at 20 and 25 cm from treatment field edge. TLDs (LiF:MgTi) were also kept at same distance. TLDs were also kept at 5, 10, and 15 cm from field edge. The TLDs were read with REXON reader. The readings at the respective distance were recorded for both diode and TLD. The PD was estimated by taking the ratio of measured dose at the particular distance to the prescription dose. PD was then compared with diode and TLD for LINAC and tomotherapy. Mean PD for LINAC with TLD and diode was 2.52 cGy (SD 0.69), 2.07 cGy (SD 0.88) at 20 cm, respectively, while at 25 cm, it was 1.94 cGy (SD 0.58) and 1.5 cGy (SD 0.75), respectively. Mean PD for tomotherapy with TLD and diode was 1.681 cGy (SD 0.53) and 1.58 (SD 0.44) at 20 cm, respectively. The PD was 1.24 cGy (SD 0.42) and 1.088 cGy (SD 0.35) at 25 cm, respectively, for tomotherapy. Overall, PD from tomotherapy was found lower than LINAC by the factor of 1.2-1.5 PD measurement is essential to find out the potential of secondary cancer. PD for both (conventional LINAC) and novel LINACs (tomotherapy) were measured and compared with each other. The comparison of the values for PD presented in this work and those published in the literature is difficult because of the different experimental conditions. The diode and TLD readings were reproducible and both the detector readings were comparable. (author)

  11. SU-F-T-473: Evaluation of Off-Axis And Peripheral Dose Using Different Detectors

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    Ganesan, B; Prakasarao, A; Singaravelu, G [Anna University, Chennai, TamilNadu (India); Palraj, T; Rai, R [Dr. Rai Memorial Cancer Institute, Chennai, TamilNadu (India)

    2016-06-15

    Purpose: In radiation therapy, measurement of off-axis and peripheral dose is a tedious task. The dose distribution along the beam central axis give only part of the information required for an accurate dose description inside the patient. Dose distributions in 2-D and 3-D are determined with central axis data in conjunction with off-axis dose profiles. Combining a central axis dose distribution with off-axis data results in volume dose matrix that provides 2-D and 3-D information on dose distribution. By considering the importance of these two parameters this study investigates and compares the off axis and peripheral dose measurement using Ionization chamber, MOSFET, Radiochromic film and EDR2 film. Methods: In the measurement of off-axis and peripheral doses 0.6cc farmer type chamber, EDR-2 film, MD-55 radiochromic film and MOSFET detectors were used for both 6MV and 15MV beams. The off-axis and peripheral dose was measured at every 1 cm interval by changing the position of the couch without disturbing the other experimental setup in particular, the phantom with detector position. Results: Readings were obtained for both 6MV and 15MV photon beams at SSD technique for various field size using MOSFET, Ionization chamber and Radiochromic film. The results shows the percentage difference between various detectors for various field sizes. For Peripheral dose measurement were taken from the edge of the field size and for off axis it is measured form central axis dose. Conclusion: In conclusion, our study shows that no detector is ideal and only a comparison between different detectors highlights the weaknesses of each detector. MOSFET provides adequate dose assessment in off-axis and peripheral regions in 6MV and 15MV photon beams. Film dosimetry in general a convenient method to generate one- and two-dimensional dose distributions. The result of this indicates that MOSFET is flexible tool for relative dosimetry as films.

  12. Peripheral doses of cranial pediatric IMRT performed with attenuator blocks; Doses perifericas de IMRT cranial pediatrica realizada com blocos atenuadores

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    Soboll, Danyel Scheidegger; Schitz, Ivette; Schelin, Hugo Reuters, E-mail: soboll@utfpr.edu.b, E-mail: iveteschitz@yahoo.com.b, E-mail: schelin@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Silva, Ricardo Goulart da, E-mail: ricardo.goulart@ymail.co [Hospital Angelina Caron, Campina Grande do Sul, PR (Brazil); Viamonte, Alfredo, E-mail: aviamonte@inca.gov.b [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

    2011-10-26

    This paper presents values of peripheral doses measured at six vital points of simulator objects which represent the ages of 2, 5 and 10 years old, submitted to a cranial IMRT procedure that applied compensator blocks interposed to 6 MV beams. The found values indicate that there is independence of dose with position of measurements and age of the patient, as the peripheral dose at the points nearest and the 2 year old simulator object where larger. The doses in thyroid reached the range of 1.4 to 2.9% of the dose prescribed in the isocenter, indicating that the peripheral doses for IMRT that employ compensator blocks can be greater than for the IMRT produced with sliding window technique

  13. Dose measurements in mammography

    International Nuclear Information System (INIS)

    Kainberger, F.; Kallinger, W.

    1977-01-01

    Dose measurements at the mamma during mammography were carried out in the form of direct measurement with thermoluminescent dosimetry. Measurement was done for the in- and outcoming doses at the mamma, the dose exposure of the sternal region and the scattered rays above the symphysis, the latter as parameter for the genetic radiation exposure. As expected, the dose of the smooth radiation used for mammography showed a strong decrease at the outcome point in comparison with the income point. Surprisingly high was the scattered radiation in the sternal region. A corresponding protection by lead plates could be taken into consideration. Extremely low is the scattered radiation above the symphysis. Even measurements with the very sensitive calcium fluoride dosimeters did not reveal any practically important dose in the symphysis region. Most measurement values remained below the determinable dose of 0.3mR. Some maximal values varied in the range of 3-1 mR. (orig.) [de

  14. Study of the CT peripheral dose variation in a head phantom

    International Nuclear Information System (INIS)

    Mourao, Arnaldo P.

    2009-01-01

    The computed tomography is frequently used for the brain diagnosis and it is responsible for the largest doses in the head among the X-ray examinations. Established indexes define a reference dose value for a scan routine; however the dose value has a longitudinal variation in the scan. The purpose of this study is to investigate the variation of the peripheral doses in the head scan using a polymethylmethacrylate head phantom. The studies were performed using two different computed tomography scanners in the option single slice with a routine of a head adult protocol (i.e. default protocol in the scanner software). Radiation doses were measured using thermoluminescent dosimeter (LiF - TLD) rod model, distributed inside the PMMA head phantom in periphery and central area. The results allowed registering the variation dose curve, longitudinally the scan, for the peripheral area and to determine the MSAD value. The peripheral maximum dose value measured can be compared with the maximum dose value in the center of the phantom in each different routine (author)

  15. Radiation dose measurements

    International Nuclear Information System (INIS)

    1960-01-01

    About 200 scientists from 28 countries and 5 international organizations met at a symposium on radiation dosimetry held by the International Atomic Energy Agency in June 1960. The aim of the symposium was not so much the description of a large number of measuring instruments as a discussion of the methods used, with special emphasis on those problems which had become important in the context of recent developments, such as the measurement of mixed or very large doses

  16. Position displacement effect on the doses in the peripheral head regions

    International Nuclear Information System (INIS)

    Kortesniemi, M.; Seppaelae, T.; Bjugg, H.; Seren, T.; Kotiluoto, P.; Auterinen, I.; Parkkinen, R.; Savolainen, S.

    2000-01-01

    Patient positioning is a challenging task in BNCT-treatments due to the use of multiple fields and a static horizontal beam construction. Positioning accuracy of 5 mm is required for acceptable dose delivery within appropriate limits of dose uncertainty (up to 10% of point dose in target volume). The aim of this study was to determine if a patient head position creating a clear gap between the beam port and the head would have a significant effect on the doses to the peripheral regions of the head, e.g. to the eyes. The gamma dose rates were measured in a water filled ellipsoidal phantom with an ionisation chamber (IC). Mn activation wires were used to determine the Mn-55(n, γ) reaction rates. Twelve measurement points were chosen in the phantom and two phantom positions were applied. According to this study the 35 mm position change and the resulting gap has an obvious effect on the peripheral doses in BNCT. The Mn activation reaction rates were on the average 80% higher in the deviation position than in the reference position. Increasing depth from the surface inside the phantom diminished the gamma dose difference between the two positions. Scattering environment changes with position displacement and resulting gap causes differences in neutron fluences and gamma doses. (author)

  17. Peripheral photon and neutron doses from prostate cancer external beam irradiation.

    Science.gov (United States)

    Bezak, Eva; Takam, Rundgham; Marcu, Loredana G

    2015-12-01

    Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative. Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for (6)LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy(-1) for thyroid and 7.0±5.4 mSv Gy(-1) for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy(-1) for thyroid and 8.1±9.7 mSv Gy(-1) for colon. Paired (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. The peripheral dose outside the applicator in electron beams of Oncor linear accelerator

    International Nuclear Information System (INIS)

    Iktueren, B.; Bilge, H.; Karacam, S.; Atkovar, G.

    2012-01-01

    In this study, the peripheral dose outside the applicator was measured using electron beams produced by an Oncor linear accelerator and compared with the data of the treatment planning system (TPS). The dose profiles have been measured, by using a water-equivalent slab phantom and a parallel plate ionisation chamber, at 6, 9 and 15 MeV energy levels in 5 x 5, 10 x 10, 15 x 15, 20 x 20 and 25 x 25 cm 2 applicators and at 0, 10 and 20 deg. gantry angles; and at the surface, 0.2, 0.5, 1 cm and d max depth for each electron energy level. The peripheral dose has been determined with these profiles by normalisation at the field central beam axis (CAX). It has been noticed that, using a 10 x 10 cm 2 applicator, there is a 1.4 % dose peak on the surface 6 cm away from the field edge where the field CAX is at 100 %, at a gantry angle of 0 deg. with 6 and 9 MeV electron beams; also for the 15 MeV electron beam there is a 2.3 % dose peak. It has been discovered that the peak dose approaches a minimum depending on the increase in depth and reaches 2.5-4 % depending on the growth of the field dimension. At gantry angles of 10 and 20 deg., 6 and 9 MeV electron beams created small peaks and a maximum dose could be reached at 0.2 and 1 cm depth. Electron beam of 15 MeV did not peak at depths of 0.2 and 1 cm at gantry angles of 10 and 20 deg.. The measured peripheral dose outside the applicators has been compared with the data from a TPS's computer using the Pencil Beam algorithm; it has been stated that dose calculations can be made as far as 3 cm outside the field. In conclusion, the TPS is not sufficient to measure the peripheral dose outside the applicators, and this dose can only be determined by direct measurement. (authors)

  19. The peripheral dose outside the applicator in electron beams of Oncor linear accelerator.

    Science.gov (United States)

    Iktueren, Basak; Bilge, Hatice; Karacam, Songul; Atkovar, Gulyuz

    2012-06-01

    In this study, the peripheral dose outside the applicator was measured using electron beams produced by an Oncor linear accelerator and compared with the data of the treatment planning system (TPS). The dose profiles have been measured, by using a water-equivalent slab phantom and a parallel plate ionisation chamber, at 6, 9 and 15 MeV energy levels in 5×5, 10×10, 15×15, 20×20 and 25×25 cm(2) applicators and at 0, 10 and 20° gantry angles; and at the surface, 0.2, 0.5, 1 cm and d(max) depth for each electron energy level. The peripheral dose has been determined with these profiles by normalisation at the field central beam axis (CAX). It has been noticed that, using a 10×10 cm(2) applicator, there is a 1.4 % dose peak on the surface 6 cm away from the field edge where the field CAX is at 100 %, at a gantry angle of 0° with 6 and 9 MeV electron beams; also for the 15 MeV electron beam there is a 2.3 % dose peak. It has been discovered that the peak dose approaches a minimum depending on the increase in depth and reaches 2.5-4 % depending on the growth of the field dimension. At gantry angles of 10 and 20°, 6 and 9 MeV electron beams created small peaks and a maximum dose could be reached at 0.2 and 1 cm depth. Electron beam of 15 MeV did not peak at depths of 0.2 and 1 cm at gantry angles of 10 and 20°. The measured peripheral dose outside the applicators has been compared with the data from a TPS's computer using the Pencil Beam algorithm; it has been stated that dose calculations can be made as far as 3 cm outside the field. In conclusion, the TPS is not sufficient to measure the peripheral dose outside the applicators, and this dose can only be determined by direct measurement.

  20. Peripheral doses in patients undergoing Cyberknife treatment for intracranial lesions. A single centre experience

    International Nuclear Information System (INIS)

    Vlachopoulou, Vassiliki; Antypas, Christos; Delis, Harry; Tzouras, Argyrios; Salvaras, Nikolaos; Kardamakis, Dimitrios; Panayiotakis, George

    2011-01-01

    Stereotactic radiosurgery/radiotherapy procedures are known to deliver a very high dose per fraction, and thus, the corresponding peripheral dose could be a limiting factor for the long term surviving patients. The aim of this clinical study was to measure the peripheral dose delivered to patients undergoing intracranial Cyberknife treatment, using the MOSFET dosimeters. The influence of the supplemental shielding, the number of monitor units and the collimator size to the peripheral dose were investigated. MOSFET dosimeters were placed in preselected anatomical regions of the patient undergoing Cyberknife treatment, namely the thyroid gland, the nipple, the umbilicus and the pubic symphysis. The mean peripheral doses before the supplemental shielding was added to the Cyberknife unit were 51.79 cGy, 13.31 cGy and 10.07 cGy while after the shielding upgrade they were 38.40 cGy, 10.94 cGy, and 8.69 cGy, in the thyroid gland, the umbilicus and the pubic symphysis, respectively. The increase of the collimator size corresponds to an increase of the PD and becomes less significant at larger distances, indicating that at these distances the PD is predominate due to the head leakage and collimator scatter. Weighting the effect of the number of monitor units and the collimator size can be effectively used during the optimization procedure in order to choose the most suitable treatment plan that will deliver the maximum dose to the tumor, while being compatible with the dose constraints for the surrounding organs at risk. Attention is required in defining the thyroid gland as a structure of avoidance in the treatment plan especially in patients with benign diseases

  1. Peripheral doses in patients undergoing Cyberknife treatment for intracranial lesions. A single centre experience

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    Vlachopoulou Vassiliki

    2011-11-01

    Full Text Available Abstract Background Stereotactic radiosurgery/radiotherapy procedures are known to deliver a very high dose per fraction, and thus, the corresponding peripheral dose could be a limiting factor for the long term surviving patients. The aim of this clinical study was to measure the peripheral dose delivered to patients undergoing intracranial Cyberknife treatment, using the MOSFET dosimeters. The influence of the supplemental shielding, the number of monitor units and the collimator size to the peripheral dose were investigated. Methods MOSFET dosimeters were placed in preselected anatomical regions of the patient undergoing Cyberknife treatment, namely the thyroid gland, the nipple, the umbilicus and the pubic symphysis. Results The mean peripheral doses before the supplemental shielding was added to the Cyberknife unit were 51.79 cGy, 13.31 cGy and 10.07 cGy while after the shielding upgrade they were 38.40 cGy, 10.94 cGy, and 8.69 cGy, in the thyroid gland, the umbilicus and the pubic symphysis, respectively. The increase of the collimator size corresponds to an increase of the PD and becomes less significant at larger distances, indicating that at these distances the PD is predominate due to the head leakage and collimator scatter. Conclusion Weighting the effect of the number of monitor units and the collimator size can be effectively used during the optimization procedure in order to choose the most suitable treatment plan that will deliver the maximum dose to the tumor, while being compatible with the dose constraints for the surrounding organs at risk. Attention is required in defining the thyroid gland as a structure of avoidance in the treatment plan especially in patients with benign diseases.

  2. Does IMRT increase the peripheral radiation dose? A comparison of treatment plans 2000 and 2010

    International Nuclear Information System (INIS)

    Salz, Henning; Eichner, Regina; Wiezorek, Tilo

    2012-01-01

    It has been reported in several papers and textbooks that IMRT treatments increase the peripheral dose in comparison with non-IMRT fields. But in clinical practice not only open fields have been used in the pre-IMRT era, but also fields with physical wedges or composed fields. The aim of this work is to test the hypothesis of increased peripheral dose when IMRT is used compared to standard conformal radiotherapy. Furthermore, the importance of the measured dose differences in clinical practice is discussed and compared with other new technologies for the cases where an increase of the peripheral dose was observed. For cancers of the head and neck, the cervix, the rectum and for the brain irradiation due to acute leukaemia, one to four plans have been calculated with IMRT or conformal standard technique (non-IMRT). In an anthropomorphic phantom the dose at a distance of 30 cm in cranio-caudal direction from the target edge was measured with TLDs using a linear accelerator Oncor registered (Siemens) for both techniques. IMRT was performed using step-and-shoot technique (7 to 11 beams), non-IMRT plans with different techniques. The results depended on the site of irradiation. For head and neck cancers IMRT resulted in an increase of 0.05 - 0.09% of the prescribed total dose (Dptv) or 40 - 70 mGy (Dptv = 65 Gy), compared to non-IMRT technique without wedges or a decrease of 0.16% (approx. 100 mGy) of the prescribed total dose compared to non-IMRT techniques with wedges. For the cervical cancer IMRT resulted in an increased dose in the periphery (+ 0.07% - 0.15% of Dptv or 30 - 70 mGy at Dptv = 45 Gy), for the rectal cancer in a dose reduction (0.21 - 0.26% of Dptv or 100 - 130 mGy at Dptv = 50 Gy) and for the brain irradiation in an increase dose (+ 0.05% of Dptv = 18 Gy or 9 mSv). In summary IMRT does not uniformly cause increased radiation dose in the periphery in the model used. It can be stated that these dose values are smaller than reported in earlier papers

  3. Intercomparison On Depth Dose Measurement

    International Nuclear Information System (INIS)

    Rohmah, N; Akhadi, M

    1996-01-01

    Intercomparation on personal dose evaluation system has been carried out between CSRSR-NAEA of Indonesia toward Standard Laboratory of JAERI (Japan) and ARL (Australia). The intercomparison was in 10 amm depth dose measurement , Hp (10), from the intercomparison result could be stated that personal depth dose measurement conducted by CSRSR was sufficiently good. Deviation of dose measurement result using personal dosemeter of TLD BG-1 type which were used by CSRSR in the intercomparison and routine photon personal dose monitoring was still in internationally agreed limit. Maximum deviation of reported doses by CSRSR compared to delivered doses for dosemeter irradiation by JAERI was -10.0 percent and by ARL was +29 percent. Maximum deviation permitted in personal dose monitoring is ± 50 percent

  4. A new online detector for estimation of peripheral neutron equivalent dose in organ

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L., E-mail: leticia@us.es; Sanchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Lorenzoli, M.; Pola, A. [Departimento di Ingegneria Nuclear, Politecnico di Milano, Milano 20133 (Italy); Bedogni, R. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN), Frascati Roma 00044 (Italy); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Sanchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Expósito, M. R. [Departamento de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Lagares, J. I.; Sansaloni, F. [Centro de Investigaciones Energéticas y Medioambientales y Tecnológicas (CIEMAT), Madrid 28040 (Spain)

    2014-11-01

    Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an

  5. A new online detector for estimation of peripheral neutron equivalent dose in organ

    International Nuclear Information System (INIS)

    Irazola, L.; Sanchez-Doblado, F.; Lorenzoli, M.; Pola, A.; Bedogni, R.; Terrón, J. A.; Sanchez-Nieto, B.; Expósito, M. R.; Lagares, J. I.; Sansaloni, F.

    2014-01-01

    Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an

  6. SU-E-T-43: Analytical Model for Photon Peripheral Dose in Radiotherapy Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Nieto, B Sanchez; El far, R [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago, Santiago De Chile (Chile); Romero-Exposito, M [Universitat Autonoma de Barcelona, Barcelona (Spain); Lagares, J [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Madrid (Spain); Mateo, JC [Hospital Duques del Infantado, Sevilla (Spain); Terron, JA [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Irazola, L; Sanchez-Doblado, F [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Departamento de Fisiologia Medica y Biofisica, Universidad de Sevilla, Sevilla (Spain)

    2014-06-01

    Purpose: The higher survival rate of radiotherapy patients entails a growing concern on second cancers associated to peripheral doses. Currently, dosimetry of out-of field doses is still under development. Our group has developed a methodology to estimate neutron equivalent dose in organs (1,2). We aimed to propose a model to estimate out-of-field photon doses in isocentric treatments from basic clinical data. Methods: The proposed function models the dose as the sum of leakage and scatter terms. The latter is modeled as a virtual source at the collimator, which suffers from attenuation in air and tissue, corrected by the inverse-square-law. The model was parameterized using experimental measurements with TLD700 chips placed inside an anthropomorphic phantom (6–18MV) irradiated with conformal and modulated techniques in Elekta, Siemens and Varian linacs. This model provides photon dose at a point as a function of clinical parameters as prescription dose/UM, PTV volume, distance to the field edge, height of the MLC leaves and distance from the the MLC to the isocenter. Model was tested against independent measurements (TLD100) for a VMAT treatment on a Elekta. Dose to organs is modeled from dose to points along the head-to-feet axis of the organ of a “standard man” escalated by patient height. Results: Our semi-empirical model depends on 3 given parameters (leakage parameter can be individualized). A novelty of our model, over other models (e.g., PERIDOSE), arises from its applicability to any technique (independently of the number of MU needed to deliver a dose). Differences between predictions and measurements were < 0.005mSv/UM. Conclusion: We have proposed a unique model which successfully account for photon peripheral organ dose. This model can be applied in the day-to-day clinic as it only needs a few basic parameters which are readily accessible.1. Radiother. Oncol. 107:234–243, 2013. 2. Phys. Med. Biol. 57:6167–6191, 2012.

  7. SU-E-T-43: Analytical Model for Photon Peripheral Dose in Radiotherapy Treatments

    International Nuclear Information System (INIS)

    Nieto, B Sanchez; El far, R; Romero-Exposito, M; Lagares, J; Mateo, JC; Terron, JA; Irazola, L; Sanchez-Doblado, F

    2014-01-01

    Purpose: The higher survival rate of radiotherapy patients entails a growing concern on second cancers associated to peripheral doses. Currently, dosimetry of out-of field doses is still under development. Our group has developed a methodology to estimate neutron equivalent dose in organs (1,2). We aimed to propose a model to estimate out-of-field photon doses in isocentric treatments from basic clinical data. Methods: The proposed function models the dose as the sum of leakage and scatter terms. The latter is modeled as a virtual source at the collimator, which suffers from attenuation in air and tissue, corrected by the inverse-square-law. The model was parameterized using experimental measurements with TLD700 chips placed inside an anthropomorphic phantom (6–18MV) irradiated with conformal and modulated techniques in Elekta, Siemens and Varian linacs. This model provides photon dose at a point as a function of clinical parameters as prescription dose/UM, PTV volume, distance to the field edge, height of the MLC leaves and distance from the the MLC to the isocenter. Model was tested against independent measurements (TLD100) for a VMAT treatment on a Elekta. Dose to organs is modeled from dose to points along the head-to-feet axis of the organ of a “standard man” escalated by patient height. Results: Our semi-empirical model depends on 3 given parameters (leakage parameter can be individualized). A novelty of our model, over other models (e.g., PERIDOSE), arises from its applicability to any technique (independently of the number of MU needed to deliver a dose). Differences between predictions and measurements were < 0.005mSv/UM. Conclusion: We have proposed a unique model which successfully account for photon peripheral organ dose. This model can be applied in the day-to-day clinic as it only needs a few basic parameters which are readily accessible.1. Radiother. Oncol. 107:234–243, 2013. 2. Phys. Med. Biol. 57:6167–6191, 2012

  8. Influence of dose-time relationship on the pathogenesis of peripheral neuropathy

    International Nuclear Information System (INIS)

    Kogelnik, H.D.; Vienna Univ.

    1977-01-01

    The development of peripheral neutopathies of cranial nerves and of the brachial plexus following curative doses of irradiation is closely related with the total dose applied, the number and size of the individual doses per fraction and the overall time. Additional important factors for the occurrence of these late complications are the volume of tissue irradiated and the stage of disease. In the pathogenesis of peripheral neuropathy a combined effect of different factors seems likely. (orig.) [de

  9. Biological radiation dose estimation by chromosomal aberrations analysis in human peripheral blood (dose-effect curve)

    International Nuclear Information System (INIS)

    Al-Achkar, W.

    2001-09-01

    In order to draw a dose-effect curve, experimentally gamma ray induced chromosomal aberrations in human peripheral lymphocytes from eight healthy people were studied. Samples from 4 males and 4 females were irradiated in tubes with 0.15, 0.25, 0.5, 1, 1.5, 2, 2.5 gray of gamma ray (Co 60 at dose rate 0.3 Gy/min). Irradiated and control samples were incubated in 37 centigrade for 48 hours cell cultures. Cell cultures then were stopped and metaphases spread, Giemsa stained to score the induced chromosomal aberrations. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics + rings and total numbers of breaks in cell for each individual or for all people were drawn. An increase of all chromosomal aberrations types with the elevation of the doses was observed. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

  10. Evaluation of the peripheral dose in stereotactic radiotherapy and radiosurgery treatments

    Energy Technology Data Exchange (ETDEWEB)

    Di Betta, Erika; Fariselli, Laura; Bergantin, Achille; Locatelli, Federica; Del Vecchio, Antonella; Broggi, Sara; Fumagalli, Maria Luisa [Department of Neurosurgery, Division of Medical Physics, Fondazione IRCCS, Istituto Neurologico C. Besta, 20133 Milano (Italy); Department of Neurosurgery, Division of Radiotherapy, Fondazione IRCCS, Istituto Neurologico C. Besta, 20133 Milano (Italy); CyberKnife Centre, Centro Diagnostico Italiano, 20147 Milano (Italy); Division of Medical Physics, Fondazione IRCCS, Istituto S. Raffaele, 20132 Milano (Italy); Department of Neurosurgery, Division of Medical Physics, Fondazione IRCCS, Istituto Neurologico C. Besta, 20133 Milano (Italy)

    2010-07-15

    Purpose: The main purpose of this work was to compare peripheral doses absorbed during stereotactic treatment of a brain lesion delivered using different devices. These data were used to estimate the risk of stochastic effects. Methods: Treatment plans were created for an anthropomorphic phantom and delivered using a LINAC with stereotactic cones and a multileaf collimator, a CyberKnife system (before and after a supplemental shielding was applied), a TomoTherapy system, and a Gamma Knife unit. For each treatment, 5 Gy were prescribed to the target. Measurements were performed with thermoluminescent dosimeters inserted roughly in the position of the thyroid, sternum, upper lung, lower lung, and gonads. Results: Mean doses ranged from of 4.1 (Gamma Knife) to 62.8 mGy (LINAC with cones) in the thyroid, from 2.3 (TomoTherapy) to 30 mGy (preshielding CyberKnife) in the sternum, from 1.7 (TomoTherapy) to 20 mGy (preshielding CyberKnife) in the upper part of the lungs, from 0.98 (Gamma Knife) to 15 mGy (preshielding CyberKnife) in the lower part of the lungs, and between 0.3 (Gamma Knife) and 10 mGy (preshielding CyberKnife) in the gonads. Conclusions: The peripheral dose absorbed in the sites of interest with a 5 Gy fraction is low. Although the risk of adverse side effects calculated for 20 Gy delivered in 5 Gy fractions is negligible, in the interest of optimum patient radioprotection, further studies are needed to determine the weight of each contributor to the peripheral dose.

  11. Evaluation of the peripheral dose in stereotactic radiotherapy and radiosurgery treatments

    International Nuclear Information System (INIS)

    Di Betta, Erika; Fariselli, Laura; Bergantin, Achille; Locatelli, Federica; Del Vecchio, Antonella; Broggi, Sara; Fumagalli, Maria Luisa

    2010-01-01

    Purpose: The main purpose of this work was to compare peripheral doses absorbed during stereotactic treatment of a brain lesion delivered using different devices. These data were used to estimate the risk of stochastic effects. Methods: Treatment plans were created for an anthropomorphic phantom and delivered using a LINAC with stereotactic cones and a multileaf collimator, a CyberKnife system (before and after a supplemental shielding was applied), a TomoTherapy system, and a Gamma Knife unit. For each treatment, 5 Gy were prescribed to the target. Measurements were performed with thermoluminescent dosimeters inserted roughly in the position of the thyroid, sternum, upper lung, lower lung, and gonads. Results: Mean doses ranged from of 4.1 (Gamma Knife) to 62.8 mGy (LINAC with cones) in the thyroid, from 2.3 (TomoTherapy) to 30 mGy (preshielding CyberKnife) in the sternum, from 1.7 (TomoTherapy) to 20 mGy (preshielding CyberKnife) in the upper part of the lungs, from 0.98 (Gamma Knife) to 15 mGy (preshielding CyberKnife) in the lower part of the lungs, and between 0.3 (Gamma Knife) and 10 mGy (preshielding CyberKnife) in the gonads. Conclusions: The peripheral dose absorbed in the sites of interest with a 5 Gy fraction is low. Although the risk of adverse side effects calculated for 20 Gy delivered in 5 Gy fractions is negligible, in the interest of optimum patient radioprotection, further studies are needed to determine the weight of each contributor to the peripheral dose.

  12. Technical Report: Evaluation of peripheral dose for flattening filter free photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Covington, E. L.; Moran, J. M.; Owrangi, A. M.; Prisciandaro, J. I., E-mail: joannp@med.umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States); Ritter, T. A. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 and Department of Radiation Oncology, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan 48105 (United States)

    2016-08-15

    Purpose: To develop a comprehensive peripheral dose (PD) dataset for the two unflattened beams of nominal energy 6 and 10 MV for use in clinical care. Methods: Measurements were made in a 40 × 120 × 20 cm{sup 3} (width × length × depth) stack of solid water using an ionization chamber at varying depths (dmax, 5, and 10 cm), field sizes (3 × 3 to 30 × 30 cm{sup 2}), and distances from the field edge (5–40 cm). The effects of the multileaf collimator (MLC) and collimator rotation were also evaluated for a 10 × 10 cm{sup 2} field. Using the same phantom geometry, the accuracy of the analytic anisotropic algorithm (AAA) and Acuros dose calculation algorithm was assessed and compared to the measured values. Results: The PDs for both the 6 flattening filter free (FFF) and 10 FFF photon beams were found to decrease with increasing distance from the radiation field edge and the decreasing field size. The measured PD was observed to be higher for the 6 FFF than for the 10 FFF for all field sizes and depths. The impact of collimator rotation was not found to be clinically significant when used in conjunction with MLCs. AAA and Acuros algorithms both underestimated the PD with average errors of −13.6% and −7.8%, respectively, for all field sizes and depths at distances of 5 and 10 cm from the field edge, but the average error was found to increase to nearly −69% at greater distances. Conclusions: Given the known inaccuracies of peripheral dose calculations, this comprehensive dataset can be used to estimate the out-of-field dose to regions of interest such as organs at risk, electronic implantable devices, and a fetus. While the impact of collimator rotation was not found to significantly decrease PD when used in conjunction with MLCs, results are expected to be machine model and beam energy dependent. It is not recommended to use a treatment planning system to estimate PD due to the underestimation of the out-of-field dose and the inability to calculate dose

  13. COMPARISON OF THE PERIPHERAL DOSES FROM DIFFERENT IMRT TECHNIQUES FOR PEDIATRIC HEAD AND NECK RADIATION THERAPY.

    Science.gov (United States)

    Toyota, Masahiko; Saigo, Yasumasa; Higuchi, Kenta; Fujimura, Takuya; Koriyama, Chihaya; Yoshiura, Takashi; Akiba, Suminori

    2017-11-01

    Intensity-modulated radiation therapy (IMRT) can deliver high and homogeneous doses to the target area while limiting doses to organs at risk. We used a pediatric phantom to simulate the treatment of a head and neck tumor in a child. The peripheral doses were examined for three different IMRT techniques [dynamic multileaf collimator (DMLC), segmental multileaf collimator (SMLC) and volumetric modulated arc therapy (VMAT)]. Peripheral doses were evaluated taking thyroid, breast, ovary and testis as the points of interest. Doses were determined using a radio-photoluminescence glass dosemeter, and the COMPASS system was used for three-dimensional dose evaluation. VMAT achieved the lowest peripheral doses because it had the highest monitor unit efficiency. However, doses in the vicinity of the irradiated field, i.e. the thyroid, could be relatively high, depending on the VMAT collimator angle. DMLC and SMLC had a large area of relatively high peripheral doses in the breast region. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Investigation of intracranial peripheral dose arising from the treatment of large lesions with Leksell GammaKnife Perfexion.

    Science.gov (United States)

    Ruschin, Mark; Nordström, Håkan; Kjäll, Per; Cho, Young-Bin; Jaffray, David

    2009-06-01

    This investigation involves quantifying the extent of intracranial peripheral dose arising from simulated targets situated in the skull-base or upper-spine region using the Leksell GammaKnife Perfexion treatment unit. For each of three spherical target volumes--denoted as Vs (4 cm3), VM (18 cm3), and VL (60 cm3)--three treatment plans were manually generated, one for each of the three collimator sizes--4, 8, and 16 mm. Each of the plans was delivered to a spherical dosimetry phantom with an insert containing EBT Gafchromic film. The total dose at 70 mm from the targets' edges, %D(70 mm), was measured as a function of elevation angle and expressed as a percentage of the prescription dose. The film insert was placed centered in the median sagittal plane (Leksell X = 100) and %D(70 mm) was measured for the angular range from 0 degree (superior/along Z axis) to 90 degrees (anterior/along Y axis). For a given collimator i, the irradiation time ti to treat a spherical target of volume V using the 50% isodose line was observed to follow a power-law relationship of the form ti = Ai(V/ Vi)n where Ai was the maximum dose divided by collimator dose rate and Vi was the volume encompassed by the 50% isodose line for a single shot. The mean value of n was 0.61 (range: 0.61-0.62). Along the superior (Z) direction (angle=0 degree) and up to angles of around 30 degrees, the %D(70 mm) was always highest for the 4 mm plans, followed by the 8 mm, followed by the 16 mm. In this angular range, the maximum measured %D(70 mm) was 1.7% of the prescription dose. The intracranial peripheral dose along the superior direction (combined scatter and leakage dose) resulting from irradiation of upper-spine or base-of-skull lesions is measured to be less than 2% of the prescription dose, even for very large (60 cm3) targets. The results of this study indicate that, for a given target volume, treatment plans consisting of only 4 mm shots yield larger peripheral dose in the superior direction than 8

  15. Peripheral doses in modulated intensive radiotherapy (MIRT) and its implications in radiological protection

    International Nuclear Information System (INIS)

    Cobos, Agustin C.; Sanz, Dario E.; Alvarez, Guilhermo D.

    2013-01-01

    A calculation model based on the theory of photon transport, to estimate the peripheral energy fluence (fluence occurring outside the radiation beam) produced by the dispersions of photon compensating filters used was developed in IMRT mode, in a treatment room radiotherapy service of FUESMEN. In order to validate the model were experimentally determined fluences and peripheral dose for three different sizes of compensating filters. It was found that there is a slight systematic overestimation model with respect to experimental results. The experimental values also allowed the comparison of the peripheral doses with other modalities. Furthermore, a model was developed to estimate the annual dose that occurs at any point to be protected with a shield, from the theoretical values obtained from peripheral energy flow. Using the theoretical values automatically allowed to take a conservative approach because of the slight overestimation already mentioned, the couple have a calculation model for widespread use. It was found that the contribution of the peripheral dose to the annual dose is more than significant, thus suggesting that the same should be considered in the design calculations of secondary barriers

  16. Measurement by film dosimetry and calculation of energy dose distributions for electron and photon irradiation of 42 MeV using the Alderson phantom for planning of pendulum irradiation of the mediastinum in the treatment of peripheral bronchial carcinomas

    International Nuclear Information System (INIS)

    Foerster, W.

    1980-01-01

    The energy dose distribution in an Alderson phantom applying a radiation energy of 42 MeV has been determined by film dosimetry and computation; the results have been compared in order to verify both methods and to improve the irradiation of bronchial carcinoma by achieving the best possible protection of healthy tissue and of the spinal cord. The comparative evaluations have shown that there is a good agreement between the calculated results and those measured by film dosimetry. (orig.) [de

  17. High-dose thalidomide increases the risk of peripheral neuropathy in the treatment of ankylosing spondylitis

    Directory of Open Access Journals (Sweden)

    Hong-xia Xue

    2015-01-01

    Full Text Available Thalidomide is an effective drug for the treatment of ankylosing spondylitis but might induce peripheral neuropathy. This major adverse reaction has attracted much concern. The current study aimed to observe the incidence of thalidomide-induced peripheral neuropathy among ankylosing spondylitis patients for 1 year after treatment. In this study, 207 ankylosing spondylitis cases received thalidomide treatment, while 116 ankylosing spondylitis cases received other treatments. Results showed that the incidence of thalidomide-induced peripheral neuropathy in the thalidomide group was higher than that in the non-thalidomide group. There was no significant difference in the incidence of neuropathy between the < 6 months medication and ≥ 6 months medication groups. There were no differences in the mean age, gender, or daily dose between the two groups. The incidence of peripheral neuropathy among patients receiving 25, 50, 75, or 100 mg thalidomide per day was 4.6%, 8.5%, 17.1%, 21.7%, respectively. The incidence was significantly different between the groups receiving 25 mg and 100 mg thalidomide. In conclusion, thalidomide can induce peripheral neuropathy within 1 year after treatment of ankylosing spondylitis; however, age and gender have no obvious impact on the incidence of peripheral neuropathy. The incidence of peripheral neuropathy is associated with increasing daily doses of thalidomide.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  19. In vivo measurement of urethral dose profiles

    International Nuclear Information System (INIS)

    Toye, W.C.; Royal Melbourne Institute of Technology,; Duchesne, G.M.; Das, K.R.; Cee, A.; Mameghan, H.; Johnston, P.N.

    2001-01-01

    Full text: Quality assurance becomes a critical requirement when radiographs are routinely used in planning of treatments. In HDR prostate brachytherapy, the surrounding organs at risk of complications are the bladder and the rectum. However, of particular concern is the urethra that runs centrally through the prostate gland, as an unavoidably high dose can occur in the central region in order to achieve a minimum peripheral dose to a small target volume. Although high urethral doses have previously been related to increased urinary symptoms, some recent studies have not found such a correlation. The aim of this study was firstly, to identify dosimetric indicators of urethral morbidity following HDR prostate brachytherapy (4F x of 5.0 Gy), and secondly, to test the validity of calculated dose values. The in vivo measurements utilised a TLD (LiF:Mg,Ti) train formed by loading eight TLD rods alternating with 1,0 cm brass spacers into a fine plastic flexible tube. The length and diameter of plastic tubing was approximately 45cm and 0.15cm respectively, while the train length was 11.8 cm from the tip of the tube. The TLD train was placed into the central lumen of an 18 F three-way urethral catheter prior to its insertion. Significant urinary morbidity was defined prospectively as a score of a total of 3 or more points for severity from 5 symptoms categories. The five symptoms evaluated were hesitancy, frequency/nocturia, dysuria, haematuria and incontinence. The introduction of in vivo measurements to enhance the existing dosimetric analysis may be required to fully test the quantitative relationships (e.g. dose-volume ratios). Placement of TLDs within the urethra results in measurements whose accuracy is unaffected by internal organ motion as the hollow urethra must move with the prostate. The dose recorded by the TLDs is determined independently of the predictive algorithm used by the treatment planning system, and prostate location errors (e.g. due to image

  20. Low-dose radiation (LDR) induces hematopoietic hormesis: LDR-induced mobilization of hematopoietic progenitor cells into peripheral blood circulation.

    Science.gov (United States)

    Li, Wei; Wang, Guanjun; Cui, Jiuwei; Xue, Lu; Cai, Lu

    2004-11-01

    The aim of this study was to investigate the stimulating effect of low-dose radiation (LDR) on bone marrow hematopoietic progenitor cell (HPC) proliferation and peripheral blood mobilization. Mice were exposed to 25- to 100-mGy x-rays. Bone marrow and peripheral blood HPCs (BFU-E, CFU-GM, and c-kit+ cells) were measured, and GM-CSF, G-CSF, and IL-3 protein and mRNA expression were detected using ELISA, slot blot hybridization, and Northern blot methods. To functionally evaluate LDR-stimulated and -mobilized HPCs, repopulation of peripheral blood cells in lethally irradiated recipients after transplantation of LDR-treated donor HPCs was examined by WBC counts, animal survival, and colony-forming units in the recipient spleens (CFUs-S). 75-mGy x-rays induced a maximal stimulation for bone marrow HPC proliferation (CFU-GM and BFU-E formation) 48 hours postirradiation, along with a significant increase in HPC mobilization into peripheral blood 48 to 72 hours postradiation, as shown by increases in CFU-GM formation and proportion of c-kit+ cells in the peripheral mononuclear cells. 75-mGy x-rays also maximally induced increases in G-CSF and GM-CSF mRNA expression in splenocytes and levels of serum GM-CSF. To define the critical role of these hematopoietic-stimulating factors in HPC peripheral mobilization, direct administration of G-CSF at a dose of 300 microg/kg/day or 150 microg/kg/day was applied and found to significantly stimulate GM-CFU formation and increase c-kit+ cells in the peripheral mononuclear cells. More importantly, 75-mGy x-rays plus 150 microg/kg/day G-CSF (LDR/150-G-CSF) produced a similar effect to that of 300 microg/kg/day G-CSF alone. Furthermore, the capability of LDR-mobilized donor HPCs to repopulate blood cells was confirmed in lethally irradiated recipient mice by counting peripheral WBC and CFUs-S. These results suggest that LDR induces hematopoietic hormesis, as demonstrated by HPC proliferation and peripheral mobilization, providing a

  1. High-dose thalidomide increases the risk of peripheral neuropathy in the treatment of ankylosing spondylitis.

    Science.gov (United States)

    Xue, Hong-Xia; Fu, Wen-Yi; Cui, Hua-Dong; Yang, Li-Li; Zhang, Ning; Zhao, Li-Juan

    2015-05-01

    Thalidomide is an effective drug for the treatment of ankylosing spondylitis but might induce peripheral neuropathy. This major adverse reaction has attracted much concern. The current study aimed to observe the incidence of thalidomide-induced peripheral neuropathy among ankylosing spondylitis patients for 1 year after treatment. In this study, 207 ankylosing spondylitis cases received thalidomide treatment, while 116 ankylosing spondylitis cases received other treatments. Results showed that the incidence of thalidomide-induced peripheral neuropathy in the thalidomide group was higher than that in the non-thalidomide group. There was no significant difference in the incidence of neuropathy between the peripheral neuropathy among patients receiving 25, 50, 75, or 100 mg thalidomide per day was 4.6%, 8.5%, 17.1%, 21.7%, respectively. The incidence was significantly different between the groups receiving 25 mg and 100 mg thalidomide. In conclusion, thalidomide can induce peripheral neuropathy within 1 year after treatment of ankylosing spondylitis; however, age and gender have no obvious impact on the incidence of peripheral neuropathy. The incidence of peripheral neuropathy is associated with increasing daily doses of thalidomide.

  2. Liposomal bupivacaine as a single-injection peripheral nerve block: a dose-response study.

    Science.gov (United States)

    Ilfeld, Brian M; Malhotra, Nisha; Furnish, Timothy J; Donohue, Michael C; Madison, Sarah J

    2013-11-01

    Currently available local anesthetics approved for single-injection peripheral nerve blocks have a maximum duration of fashion. The end points included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current in the femoral nerve distribution. Measurements were performed from baseline until quadriceps MVIC returned to 80% of baseline bilaterally. There were statistically significant dose responses in MVIC (0.09%/mg, SE = 0.03, 95% confidence interval [CI], 0.04-0.14, P = 0.002) and tolerance to cutaneous current (-0.03 mA/mg, SE = 0.01, 95% CI, -0.04 to -0.02, P 40 mg, tolerance to cutaneous current did not return to within 20% above baseline until after 24 hours in 100% of subjects (95% CI, 56%-100%). MVIC did not consistently return to within 20% of baseline until after 24 hours in 90% of subjects (95% CI, 54%-100%). Motor block duration was not correlated with bupivacaine dose (0.06 hour/mg, SE = 0.14, 95% CI, -0.27 to 0.39, P = 0.707). The results of this investigation suggest that deposition of a liposomal bupivacaine formulation adjacent to the femoral nerve results in a partial sensory and motor block of >24 hours for the highest doses examined. However, the high variability of block magnitude among subjects and inverse relationship of dose and response magnitude attests to the need for a phase 3 study with a far larger sample size, and that these results should be viewed as suggestive, requiring confirmation in a future trial.

  3. Cytogenetic Low-Dose Hyperradiosensitivity Is Observed in Human Peripheral Blood Lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Seth, Isheeta [Department of Biological Sciences, Wayne State University, Detroit, Michigan (United States); Joiner, Michael C. [Department of Radiation Oncology, Wayne State University, Detroit, Michigan (United States); Tucker, James D., E-mail: jtucker@biology.biosci.wayne.edu [Department of Biological Sciences, Wayne State University, Detroit, Michigan (United States)

    2015-01-01

    Purpose: The shape of the ionizing radiation response curve at very low doses has been the subject of considerable debate. Linear-no-threshold (LNT) models are widely used to estimate risks associated with low-dose exposures. However, the low-dose hyperradiosensitivity (HRS) phenomenon, in which cells are especially sensitive at low doses but then show increased radioresistance at higher doses, provides evidence of nonlinearity in the low-dose region. HRS is more prominent in the G2 phase of the cell cycle than in the G0/G1 or S phases. Here we provide the first cytogenetic mechanistic evidence of low-dose HRS in human peripheral blood lymphocytes using structural chromosomal aberrations. Methods and Materials: Human peripheral blood lymphocytes from 2 normal healthy female donors were acutely exposed to cobalt 60 γ rays in either G0 or G2 using closely spaced doses ranging from 0 to 1.5 Gy. Structural chromosomal aberrations were enumerated, and the slopes of the regression lines at low doses (0-0.4 Gy) were compared with doses of 0.5 Gy and above. Results: HRS was clearly evident in both donors for cells irradiated in G2. No HRS was observed in cells irradiated in G0. The radiation effect per unit dose was 2.5- to 3.5-fold higher for doses ≤0.4 Gy than for doses >0.5 Gy. Conclusions: These data provide the first cytogenetic evidence for the existence of HRS in human cells irradiated in G2 and suggest that LNT models may not always be optimal for making radiation risk assessments at low doses.

  4. Influence of dosing times on cisplatin-induced peripheral neuropathy in rats

    International Nuclear Information System (INIS)

    Seto, Yoshihiro; Okazaki, Fumiyasu; Horikawa, Keiji; Zhang, Jing; Sasaki, Hitoshi; To, Hideto

    2016-01-01

    Although cis-diamminedichloro-platinum (CDDP) exhibits strong therapeutic effects in cancer chemotherapy, its adverse effects such as peripheral neuropathy, nephropathy, and vomiting are dose-limiting factors. Previous studies reported that chronotherapy decreased CDDP-induced nephropathy and vomiting. In the present study, we investigated the influence of dosing times on CDDP-induced peripheral neuropathy in rats. CDDP (4 mg/kg) was administered intravenously at 5:00 or 17:00 every 7 days for 4 weeks to male Sprague–Dawley rats, and saline was given to the control group. To assess the dosing time dependency of peripheral neuropathy, von-Frey test and hot-plate test were performed. In order to estimate hypoalgesia, the hot-plate test was performed in rats administered CDDP weekly for 4 weeks. On day 28, the withdrawal latency to thermal stimulation was significantly prolonged in the 17:00-treated group than in the control and 5:00-treated groups. When the von-Frey test was performed to assess mechanical allodynia, the withdrawal threshold was significantly lower in the 5:00 and 17:00-treated groups than in the control group on day 6 after the first CDDP dose. The 5:00-treated group maintained allodynia throughout the experiment with the repeated administration of CDDP, whereas the 17:00-treated group deteriorated from allodynia to hypoalgesia. It was revealed that the severe of CDDP-induced peripheral neuropathy was inhibited in the 5:00-treated group, whereas CDDP-treated groups exhibited mechanical allodynia. These results suggested that the selection of an optimal dosing time ameliorated CDDP-induced peripheral neuropathy. The online version of this article (doi:10.1186/s12885-016-2777-0) contains supplementary material, which is available to authorized users

  5. Radiation dose rate measuring device

    International Nuclear Information System (INIS)

    Sorber, R.

    1987-01-01

    A portable device is described for in-field usage for measuring the dose rate of an ambient beta radiation field, comprising: a housing, substantially impervious to beta radiation, defining an ionization chamber and having an opening into the ionization chamber; beta radiation pervious electrically-conductive window means covering the opening and entrapping, within the ionization chamber, a quantity of gaseous molecules adapted to ionize upon impact with beta radiation particles; electrode means disposed within the ionization chamber and having a generally shallow concave surface terminating in a generally annular rim disposed at a substantially close spacing to the window means. It is configured to substantially conform to the window means to define a known beta radiation sensitive volume generally between the window means and the concave surface of the electrode means. The concave surface is effective to substantially fully expose the beta radiation sensitive volume to the radiation field over substantially the full ambient area faced by the window means

  6. High dose stainless steel swelling data on interior and peripheral oxide fuel pins

    International Nuclear Information System (INIS)

    Boltax, A.; Foster, J.P.; Nayak, U.P.

    1983-01-01

    High dose (2 x 10 23 n/cm 2 , E > 0.1 Mev) swelling data obtained on 20% cold-worked AISI 316 stainless steel (N-lot) cladding from mixed-oxide fuel pins show large differences in swelling incubation dose due to pre-incubation dose temperature changes. Circumferential swelling variations of 1.5 to 4 times were found in peripheral fuel pin cladding which experienced 30 to 60 deg C temperature changes due to movement in a temperature gradient. Consideration is given to the implications of these results to low swelling materials development and core design. (author)

  7. Mixed field dose equivalent measuring instruments

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  8. Radiosensitizing activity and pharmacokinetics of multiple dose administered KU-2285 in peripheral nerve tissue in mice

    International Nuclear Information System (INIS)

    Iwai, Hiroyuki; Matsuno, Etsuko; Sasai, Keisuke; Abe, Mitsuyuki; Shibamoto, Yuta

    1994-01-01

    In a clinical trial in which a 2-nitroimidazole radiosensitizer was administered repeatedly, the dose-limiting toxicity was found to be peripheral neuropathy. In the present study, the in vivo radiosensitizing activity of KU-2285 in combination with radiation dose fractionation, and the pharmacokinetics of cumulative dosing of KU-2285 in the peripheral nerves were examined. The ability of three nitroimidazoles, misonidazole (MISO), etanidazole (SR-2508) and KU-2285, to sensitize SCCVII tumors to radiation treatment has been compared for drug doses in the range 0-200 mg/kg. Single radiation doses or two different fractionation schedules (6 Gy/fractions x three fractions/48 h or 5 Gy/fractions x five fractions/48 h) were used; the tumor cell survival was determined using an in vivo/in vitro colony assay. The pharmacokinetics in the sciatic nerves were undertaken, when KU-2285 or etanidazole were injected at a dose of 200 mg/kg intravenously one, two, three, or four times at 2-h intervals. At less than 100 mg/kg, KU-2285 sensitized SCCVII tumors more than MISO and SR-2508 by fractionated irradiation. Evaluation of pharmacokinetics in the peripheral nerves showed that the apparent biological half-life of SR-2508 increased with the increases in the number of administrations, whereas that of KU-2285 became shorter. Since most clinical radiotherapy is given in small multiple fractions, KU-2285 appears to be a hypoxic cell radiosensitizer that could be useful in such regimens, and that poses no risk of chronic peripheral neurotoxicity. 12 refs., 5 figs., 1 tab

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

    African Journals Online (AJOL)

    Enrique

    SA JOURNAL OF RADIOLOGY • August 2004. Abstract. This study determined the correlation 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 ...

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

    African Journals Online (AJOL)

    This study determined the correlation 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 ...

  11. Patient dose measurement and dose reduction in East Anglia (UK)

    International Nuclear Information System (INIS)

    Wade, J.P.; Goldstone, K.E.; Dendy, P.P.

    1995-01-01

    At the end of 1990 a programme of patient dose measurements was introduced as part of the quality assurance service already provided for X ray departments throughout the East Anglian Health Region (UK). Thermoluminescence dosemeters (TLDs) were used to measure over 1200 skin entrance surface doses for four common radiographic views in 33 hospitals in both the NHS and private sector. The four views were chosen to cover a wide range of equipment and techniques. The data collected have enabled Regional reference doses to be set which, for all views considered, fall below the National Radiological Protection Board (NRPB) Reference levels. In departments which exceeded reference levels, techniques were reviewed, improvements suggested and doses re-measured, in accordance with the recommended procedure for patient dose audit. A significant finding was that, given appropriate controls, X ray departments in the private sector could achieve the same acceptably low doses as NHS departments. (Author)

  12. Evaluation of patients radiation dose from computed tomography during lower peripheral angiography procedure

    International Nuclear Information System (INIS)

    Khlafallah, Leena Ahmed Ali

    2015-09-01

    The purpose of this study was to evaluate patient radiation doses in lower peripheral angiography CT examinations in Sudan. Survey was conducted in four major hospitals which almost carry out lower peripheral angiography procedures in Sudan at the time of study. All hospitals were equipped with 64 slices multi detectors CT from Toshiba (Japan). The total number of patients was 74. Information on patient's genders and ages, exposure technique factors and radiation dose were collected. The procedures performed in multi phases, up to five phases covering part of the abdomen region, which can make patients exposure reasonably high. CTDI values in the different phases ranged between (13-30) mGy. The total DLP in the four hospitals were 6888.75, 5065.05, 6608.88 and 5754.9 mGy.cm. This study provided first survey for patient dose during lower peripheral angiography procedures in Sudan. Taking into account that the CT machines were similar: the variation between patient's DLP and CTDI values in the different hospitals indicated the need of optimization of radiation protection. Staff training and awareness on factors affecting patient dose are essential.(Author)

  13. Threshold dose for peripheral neuropathy following intraoperative radiotherapy (IORT) in a large animal model

    International Nuclear Information System (INIS)

    Kinsella, T.J.; DeLuca, A.M.; Barnes, M.; Anderson, W.; Terrill, R.; Sindelar, W.F.

    1991-01-01

    Radiation injury to peripheral nerve is a dose-limiting toxicity in the clinical application of intraoperative radiotherapy, particularly for pelvic and retroperitoneal tumors. Intraoperative radiotherapy-related peripheral neuropathy in humans receiving doses of 20-25 Gy is manifested as a mixed motor-sensory deficit beginning 6-9 months following treatment. In a previous experimental study of intraoperative radiotherapy-related neuropathy of the lumbro-sacral plexus, an approximate inverse linear relationship was reported between the intraoperative dose (20-75 Gy range) and the time to onset of hind limb paresis (1-12 mos following intraoperative radiotherapy). The principal histological lesion in irradiated nerve was loss of large nerve fibers and perineural fibrosis without significant vascular injury. Similar histological changes in irradiated nerves were found in humans. To assess peripheral nerve injury to lower doses of intraoperative radiotherapy in this same large animal model, groups of four adult American Foxhounds received doses of 10, 15, or 20 Gy to the right lumbro-sacral plexus and sciatic nerve using 9 MeV electrons. The left lumbro-sacral plexus and sciatic nerve were excluded from the intraoperative field to allow each animal to serve as its own control. Following treatment, a complete neurological exam, electromyogram, and nerve conduction studies were performed monthly for 1 year. Monthly neurological exams were performed in years 2 and 3 whereas electromyogram and nerve conduction studies were performed every 3 months during this follow-up period. With follow-up of greater than or equal to 42 months, no dog receiving 10 or 15 Gy IORT shows any clinical or laboratory evidence of peripheral nerve injury. However, all four dogs receiving 20 Gy developed right hind limb paresis at 8, 9, 9, and 12 mos following intraoperative radiotherapy

  14. Radiation therapy for stage IIA and IIB testicular seminoma: peripheral dose calculations and risk assessments

    Science.gov (United States)

    Mazonakis, Michalis; Berris, Theocharris; Lyraraki, Efrossyni; Damilakis, John

    2015-03-01

    This study was conducted to calculate the peripheral dose to critical structures and assess the radiation risks from modern radiotherapy for stage IIA/IIB testicular seminoma. A Monte Carlo code was used for treatment simulation on a computational phantom representing an average adult. The initial treatment phase involved anteroposterior and posteroanaterior modified dog-leg fields exposing para-aortic and ipsilateral iliac lymph nodes followed by a cone-down phase for nodal mass irradiation. Peripheral doses were calculated using different modified dog-leg field dimensions and an extended conventional dog-leg portal. The risk models of the BEIR-VII report and ICRP-103 were combined with dosimetric calculations to estimate the probability of developing stochastic effects. Radiotherapy for stage IIA seminoma with a target dose of 30 Gy resulted in a range of 23.0-603.7 mGy to non-targeted peripheral tissues and organs. The corresponding range for treatment of stage IIB disease to a cumulative dose of 36 Gy was 24.2-633.9 mGy. A dose variation of less than 13% was found by altering the field dimensions. Radiotherapy with the conventional instead of the modern modified dog-leg field increased the peripheral dose up to 8.2 times. The calculated heart doses of 589.0-632.9 mGy may increase the risk for developing cardiovascular diseases whereas the testicular dose of more than 231.9 mGy may lead to a temporary infertility. The probability of birth abnormalities in the offspring of cancer survivors was below 0.13% which is much lower than the spontaneous mutation rate. Abdominoplevic irradiation may increase the lifetime intrinsic risk for the induction of secondary malignancies by 0.6-3.9% depending upon the site of interest, patient’s age and tumor dose. Radiotherapy for stage IIA/IIB seminoma with restricted fields and low doses is associated with an increased morbidity. These data may allow the definition of a risk-adapted follow-up scheme for long

  15. Peripheral chemoreflex inhibition with low-dose dopamine: new insight into mechanisms of extreme apnea.

    Science.gov (United States)

    Bain, Anthony R; Dujic, Zeljko; Hoiland, Ryan L; Barak, Otto F; Madden, Dennis; Drvis, Ivan; Stembridge, Mike; MacLeod, David B; MacLeod, Douglas M; Ainslie, Philip N

    2015-11-01

    The purpose of this study was to determine the impact of peripheral chemoreflex inhibition with low-dose dopamine on maximal apnea time, and the related hemodynamic and cerebrovascular responses in elite apnea divers. In a randomized order, participants performed a maximal apnea while receiving either intravenous 2 μg·kg(-1)·min(-1) dopamine or volume-matched saline (placebo). The chemoreflex and hemodynamic response to dopamine was also assessed during hypoxia [arterial O2 tension, (PaO2 ) ∼35 mmHg] and mild hypercapnia [arterial CO2 tension (PaCO2 ) ∼46 mmHg] that mimicked the latter parts of apnea. Outcome measures included apnea duration, arterial blood gases (radial), heart rate (HR, ECG), mean arterial pressure (MAP, intra-arterial), middle (MCAv) and posterior (PCAv) cerebral artery blood velocity (transcranial ultrasound), internal carotid (ICA) and vertebral (VA) artery blood flow (ultrasound), and the chemoreflex responses. Although dopamine depressed the ventilatory response by 27 ± 41% (vs. placebo; P = 0.01), the maximal apnea duration was increased by only 5 ± 8% (P = 0.02). The PaCO2 and PaO2 at apnea breakpoint were similar (P > 0.05). When compared with placebo, dopamine increased HR and decreased MAP during both apnea and chemoreflex test (P all breathe. Copyright © 2015 the American Physiological Society.

  16. Antiproton Radiotherapy Peripheral Dose from Secondary Neutrons produced in the Annihilation of Antiprotons in the Target

    CERN Document Server

    Fahimian, Benjamin P; Keyes, Roy; Bassler, Niels; Iwamoto, Keisuke S; Zankl, Maria; Holzscheiter, Michael H

    2009-01-01

    The AD-4/ACE collaboration studies the biological effects of antiprotons with respect to a possible use of antiprotons in cancer therapy. In vitro experiments performed by the collaboration have shown an enhanced biological effectiveness for antiprotons relative to protons. One concern is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose was tallied as a function of energy and organ.

  17. Biological radiation dose estimation by chromosomal aberrations analysis in human peripheral blood (dose- effect curve)

    International Nuclear Information System (INIS)

    Al Achkar, W.

    2002-01-01

    In order to draw a dose-effect curve, blood from eight healthy people were studied. Samples were irradiated in tubes with 0.15-2.5 gray of gamma ray.Irradiated and control samples were incubated for cell cultures. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics+ rings and total numbers of breaks were drawn. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

  18. Quantification and reduction of peripheral dose from leakage radiation on Siemens Primus accelerators in electron therapy mode.

    Science.gov (United States)

    Yeboah, Collins; Karotki, Alex; Hunt, Dylan; Holly, Rick

    2010-06-15

    In this work, leakage radiation from EA200 series electron applicators on Siemens Primus accelerators is quantified, and its penetration ability in water and/or the shielding material Xenolite-NL established. Initially, measurement of leakage from 10 x 10 - 25 x 25 cm2 applicators was performed as a function of height along applicator and of lateral distance from applicator body. Relative to central-axis ionization maximum in solid water, the maximum leakage in air observed with a cylindrical ion chamber with 1 cm solid water buildup cap at a lateral distance of 2 cm from the front and right sidewalls of applicators were 17% and 14%, respectively; these maxima were recorded for 18 MeV electron beams and applicator sizes of >or=20 x 20 cm2. In the patient plane, the applicator leakage gave rise to a broad peripheral dose off-axis distance peak that shifted closer to the field edge as the electron energy increases. The maximum peripheral dose from normally incident primary electron beams at a depth of 1 cm in a water phantom was observed to be equal to 5% of the central-axis dose maximum and as high as 9% for obliquely incident beams with angles of obliquity dose curves showed that the "practical range" of the leakage electrons in water varies from approximately 1.4 to 5.7 cm as the primary electron beam energy is raised from 6 to 18 MeV. Next, transmission measurements of leakage radiation through the shielding material Xenolite-NL showed a 4 mm thick sheet of this material is required to attenuate the leakage from 9 MeV beams by two-thirds, and that for every additional 3 MeV increase in the primary electron beam energy, an additional Xenolite-NL thickness of roughly 2 mm is needed to achieve the aforementioned attenuation level. Finally, attachment of a 1 mm thick sheet of lead to the outer surface of applicator sidewalls resulted in a reduction of the peripheral dose by up to 80% and 74% for 9 and 18MeV beams, respectively. This sidewall modification had an

  19. Skin dose measurement with MICROSPEC-2 trademark

    International Nuclear Information System (INIS)

    Hsu, H.H.

    1997-01-01

    For many years, the Eberline HP-260 trademark beta detectors were used for skin dose measurements at Los Alamos National Laboratory. This detector does not measure the beta spectrum and the skin dose can only be determined if the contaminating radioactive isotope is known. A new product MICROSPEC-2 trademark, has been developed which consists of a small portable computer with a multichannel analyzer and a beta probe consisting of a phoswich detector. The system measures the beta spectrum and automatically folds in the beta fluence-to-dose conversion function to yield the skin dose

  20. Patient dose measurement and dose reduction in chest radiography

    Directory of Open Access Journals (Sweden)

    Milatović Aleksandra A.

    2014-01-01

    Full Text Available Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area product of patient doses. In the second stage, the possibilities for dose reduction were investigated. Mean kerma area product values were 0.8 ± 0.5 Gycm2 for the posterior-anterior projection and 1.6 ± 0.9 Gycm2 for the lateral projection. The max/min ratio for the entrance surface air kerma was found to be 53 for the posterior-anterior projection and 88 for the lateral projection. Comparing the results obtained in Montenegro with results from other countries, we concluded that patient doses in our medical centres are significantly higher. Changes in exposure parameters and increased filtration contributed to a dose reduction of up to 36% for posterior-anterior chest examinations. The variability of the estimated dose values points to a significant space for dose reduction throughout the process of radiological practice optimisation.

  1. Peripheral nerve and ureteralo tolerance to intraoperative radiation therapy; Clinical and dose-response analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, E.G.; Gunderson, L.L.; Martin, J.K.; Baers, R.W.; Nagorney, D.M.; Podratz, K.C. (Mayo Clinic, Rochester, MN (USA))

    1990-07-01

    Between April 1981 and July 1984, 51 received intraoperative radiation therapy (IORT) as a component of therapy for the management of primary of recurrent pelvic malignancies which were initially unresectable for cure. For these patients, curative surgical alternatives did not exist, or would have involved extensive procedures such as pelvic exenteration, distal sacrectomy, hemipelvectomy, or hemicorporectemy. The primary disease was colorectal in 38 patients. Treatment consisted of external beam radiation (range 3000 to 6890 cGy, median 5040 cGy), surgical debulking when feasible, and an intraoperative electron beam boost to the gross of microscopic residual desease (dose range 1000 to 2500 cGy, median 1750 cGy) utilizing 9-18 MeV electrons. The most common IORT associated toxicities were peripheral neurophaty and ureteral obstruction. None were life-threatening or fatal in severity. Of the 50 patients evaluable for neurotoxicity analysis, 16 (32%) developed peripheral neurophaty consisting of pain in 16 patients, numbness and tingling in 11, and weakness in 8. The pain, numbness and tingling resolved in about 40% of patients, while weakness resolved in only 1 of 8. Sixteen ureters were initially unobstructed by tumor at the time of IORT. Of these, 10 (63%) subsequently showed evidence of obstruction and hydronephrosis. The development of neurotoxicity was more common at IORT doses of 1500 cGy or more versus 1000 cGy. Ureteral obstruction with hydronephrosis occurred more frequently at IORT doses of 1250 cGy or more compared to 1000 cGy. There was no relationship between the likelihood of developing complications and the total external beam dose. The observed dependence of human nerve toxicity primarily on the IORT dose is consistent with data generated form animal experiments. (author). 21 refs.; 4 tabs.

  2. Peripheral arterial disease in a female using high-dose combined oral contraceptive pills.

    Science.gov (United States)

    Pallavee, P; Samal, Sunita; Samal, Rupal

    2013-01-01

    The association between oral contraceptive (OC) pills and vascular diseases is well-known, although, the present generation of pills is considered to be relatively safer in this regard. Hormonal treatment for severe abnormal uterine bleeding is usually considered after ruling out malignancy, when such bleeding is resistant to all other forms of treatment. We report a case of severe peripheral arterial disease in a female, who had been on high-dose OC pills for an extended period of time for severe uterine bleeding.

  3. Technical Note: Comparison of peripheral patient dose from MR-guided 60 Co therapy and 6 MV linear accelerator IGRT.

    Science.gov (United States)

    Hauri, Pascal; Hälg, Roger A; Schneider, Uwe

    2017-07-01

    The use of X-ray imaging in radiation therapy can give a substantial dose to the patient. A Cobalt machine combined with an magnetic resonance imaging (MRI) was recently introduced to clinical work. One positive aspect of using non-ionizing imaging devices is the reduction of the patient exposure. The purpose of this study was to quantify the difference in out-of-field dose to the patient between the image guided radiation therapy (IGRT) treatment applied with a linear accelerator with cone beam CT (CBCT) equipment and a Cobalt machine combined with an MRI. The treatment of a rhabdomyosarcoma in the prostate was planned and irradiated using different modalities and radiation therapy machines. The whole-body dose was measured for a 3D-conformal radiation therapy (3DCRT), an intensity-modulated radiation therapy (IMRT), and a volumetric-modulated arc therapy plan applied with a conventional linear accelerator operated at 6 MV beam energy. Additionally, the dose of an IMRT plan applied with a 60 Co machine combined with an MRI was measured. Furthermore, the dose of one CBCT scan using the linear accelerator's on-board imaging system was determined. The 3D dose measurements were performed in an anthropomorphic phantom containing 168 slots for thermoluminescence dosimeters (TLDs). A combination of LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P (TLD100H) was used to accurately determine the in- and out-of-field dose. The plans were rescaled to different fractionation schemes (2 Gy, 3 Gy, and 5 Gy fraction dose) and the dose of one CBCT scan was additionally added to the treatment dose per fraction applied with the linear accelerator. The resulting absorbed doses per fraction of the two machines were compared. In the target region, all measured treatment plans presented the same magnitude of dose, while the CBCT dose was a factor of 100 smaller. Close to the planned target volume (PTV), the dose from the 60 Co machine was a factor of two higher compared with the 3DCRT + CBCT dose. Up

  4. Need for quality dose measurements

    International Nuclear Information System (INIS)

    Forbes, J.L.

    1985-01-01

    Work procedures based upon dependable measurements have unquestionably reduced past exposures to a level that will produce few injuries in later years. Of the many legal issues that might be discussed with regard to instrument calibration, the two of present concern are the determination of cause, and the evidence (including expert testimony) submitted to that end. Although they are termed here legal issues, they are in fact highly technical problems which have recently become political footballs. Some background is discussed in order to understand how such legal/technical/political considerations are related to instrument calibration, the subject of this workshop

  5. Saliva oxytocin measures do not reflect peripheral plasma concentrations after intranasal oxytocin administration in men.

    Science.gov (United States)

    Quintana, Daniel S; Westlye, Lars T; Smerud, Knut T; Mahmoud, Ramy A; Andreassen, Ole A; Djupesland, Per G

    2018-05-16

    Oxytocin plays an important role in social behavior. Thus, there has been significant research interest for the role of the oxytocin system in several psychiatric disorders, and the potential of intranasal oxytocin administration to treat social dysfunction. Measurement of oxytocin concentrations in saliva are sometimes used to approximate peripheral levels of oxytocin; however, the validity of this approach is unclear. In this study, saliva and plasma oxytocin was assessed after two doses of Exhalation Delivery System delivered intranasal oxytocin (8 IU and 24 IU), intravenous oxytocin (1 IU) and placebo in a double-dummy, within-subjects design with men. We found that intranasal oxytocin (8 IU and 24 IU) administration increased saliva oxytocin concentrations in comparison to saliva oxytocin concentration levels after intravenous and placebo administration. Additionally, we found that saliva oxytocin concentrations were not significantly associated with plasma oxytocin concentrations after either intranasal or intravenous oxytocin administration. Altogether, we suggest that saliva oxytocin concentrations do not accurately index peripheral oxytocin after intranasal or intravenous oxytocin administration, at least in men. The data indicates that elevated oxytocin saliva levels after nasal delivery primarily reflect exogenous administered oxytocin that is cleared from the nasal cavity to the oropharynx, and is therefore a weak surrogate for peripheral blood measurements. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Technical Note: Out-of-field dose measurement at near surface with plastic scintillator detector.

    Science.gov (United States)

    Bourgouin, Alexandra; Varfalvy, Nicolas; Archambault, Louis

    2016-09-08

    Out-of-field dose depends on multiple factors, making peripheral dosimetry com-plex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements were performed with a parallel-plate ion chamber, a small volume ion chamber, and with a PSD. Lateral-dose measurements (LDM) at 0.5 cm depth and depth-dose curve (PDD) were made and compared to the dose calculation provided by a treatment planning system (TPS). This study shows that a PSD can measure a dose as low as 0.51 ± 0.17 cGy for photon beam and 0.58 ± 0.20 cGy for electron beam with a difference of 0.2 and 0.1 cGy compared to a parallel-plate ion chamber. This study demonstrates the potential of using PSD as an out-of-field dosimeter since measure-ments with PSD avoid averaging over a too-large depth, at 1 mm diameter, and can make precise measurement at very low dose. Also, electronic equilibrium is easier to reach with PSD due to its small sensitive volume and its water equivalence. © 2016 The Authors.

  7. Measurement of radiation dose in dental radiology

    International Nuclear Information System (INIS)

    Helmrot, E.; Carlsson, G. A.

    2005-01-01

    Patient dose audit is an important tool for quality control and it is important to have a well-defined and easy to use method for dose measurements. In dental radiology, the most commonly used dose parameters for the setting of diagnostic reference levels (DRLs) are the entrance surface air kerma (ESAK) for intraoral examinations and dose width product (DWP) for panoramic examinations. DWP is the air kerma at the front side of the secondary collimator integrated over the collimator width and an exposure cycle. ESAK or DWP is usually measured in the absence of the patient but with the same settings of tube voltage (kV), tube current (mA) and exposure time as with the patient present. Neither of these methods is easy to use, and, in addition, DWP is not a risk related quantity. A better method of monitoring patient dose would be to use a dose area product (DAP) meter for all types of dental examinations. In this study, measurements with a DAP meter are reported for intraoral and panoramic examinations. The DWP is also measured with a pencil ionisation chamber and the product of DWP and the height H (DWP x H) of the secondary collimator (measured using film) was compared to DAP. The results show that it is feasible to measure DAP using a DAP meter for both intraoral and panoramic examinations. The DAP is therefore recommended for the setting of DRLs. (authors)

  8. Traceability and standardization of large dose measurement

    International Nuclear Information System (INIS)

    Tanaka, Ryuichi

    1989-01-01

    The reliability of dose control for radiation sterilization and food irradiation depends on the relative errors in measurements made by different dosimeters and the level of process control techniques as well as traceability. International efforts have been made for standardization of dose measurement procedures and process control techniques. A system for traceability of large dose measurement has already been established in the U.S. and Britain, and it has become urgent in Japan to establish a traceability system. For process control for radiation sterilization of medical tools, dose measurement is replacing the use of a biological indicator to play a more important role in relation to sterilization assurance. AAMI is making efforts to establish implementation standards for process control for industrial sterilization with electron beam. In Japan, the Radiation Irradiation Promotion Association has developed a manual 'Measurement of Dose of Electron Beam for Irradiation' to be used by users of electron beam for irradiation. Further efforts are required to establish a proper traceability system and standardization of dose measurement. (N.K.)

  9. Brachytherapy dose measurements in heterogeneous tissues

    International Nuclear Information System (INIS)

    Paiva F, G.; Luvizotto, J.; Salles C, T.; Guimaraes A, P. C.; Dalledone S, P. de T.; Yoriyaz, H.; Rubo, R.

    2014-08-01

    Recently, Beau lieu et al. published an article providing guidance for Model-Based Dose Calculation Algorithms (MBDCAs), where tissue heterogeneity considerations are addressed. It is well-known that T G-43 formalism which considers only water medium is limited and significant dose differences have been found comparing both methodologies. The aim of the present work is to experimentally quantify dose values in heterogeneous medium using different dose measurement methods and techniques and compare them with those obtained with Monte Carlo simulations. Experiments have been performed using a Nucletron micro Selectron-Hdr Ir-192 brachytherapy source and a heterogeneous phantom composed by PMMA and different tissue equivalent cylinders like bone, lungs and muscle. Several dose measurements were obtained using tissue equivalent materials with height 1.8 cm and 4.3 cm positioned between the radiation source and the detectors. Radiochromic films, TLDs and MOSFET S have been used for the dose measurements. Film dosimetry has been performed using two methodologies: a) linearization for dose-response curve based on calibration curves to create a functional form that linearize s the dose response and b) 177 multichannel analysis dosimetry where the multiple color channels are analyzed allowing to address not only disturbances in the measurements caused by thickness variation in the film layer, but also, separate other external influences in the film response. All experiments have been simulated using the MCNP5 Monte Carlo radiation transport code. Comparison of experimental results are in good agreement with calculated dose values with differences less than 6% for almost all cases. (Author)

  10. Brachytherapy dose measurements in heterogeneous tissues

    Energy Technology Data Exchange (ETDEWEB)

    Paiva F, G.; Luvizotto, J.; Salles C, T.; Guimaraes A, P. C.; Dalledone S, P. de T.; Yoriyaz, H. [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Rubo, R., E-mail: gabrielpaivafonseca@gmail.com [Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, 05403-900 Sao Paulo (Brazil)

    2014-08-15

    Recently, Beau lieu et al. published an article providing guidance for Model-Based Dose Calculation Algorithms (MBDCAs), where tissue heterogeneity considerations are addressed. It is well-known that T G-43 formalism which considers only water medium is limited and significant dose differences have been found comparing both methodologies. The aim of the present work is to experimentally quantify dose values in heterogeneous medium using different dose measurement methods and techniques and compare them with those obtained with Monte Carlo simulations. Experiments have been performed using a Nucletron micro Selectron-Hdr Ir-192 brachytherapy source and a heterogeneous phantom composed by PMMA and different tissue equivalent cylinders like bone, lungs and muscle. Several dose measurements were obtained using tissue equivalent materials with height 1.8 cm and 4.3 cm positioned between the radiation source and the detectors. Radiochromic films, TLDs and MOSFET S have been used for the dose measurements. Film dosimetry has been performed using two methodologies: a) linearization for dose-response curve based on calibration curves to create a functional form that linearize s the dose response and b) 177 multichannel analysis dosimetry where the multiple color channels are analyzed allowing to address not only disturbances in the measurements caused by thickness variation in the film layer, but also, separate other external influences in the film response. All experiments have been simulated using the MCNP5 Monte Carlo radiation transport code. Comparison of experimental results are in good agreement with calculated dose values with differences less than 6% for almost all cases. (Author)

  11. Dose response relationships and analysis of primary processes of radiation-induced chromosomal aberrations in human peripheral lymphocytes

    International Nuclear Information System (INIS)

    Schmid, E.

    1977-02-01

    Human peripheral lymphocytes were irradiated with 220 kV X-rays, 3 MeV electrons and 15 MeV neutrons. The frequency of dicentric, acentric and atypical chromosomes and the exhange aberrations were measured and dose effect curves were constructed. The aim is to prepare the chromosome analysis to a biological dosimetry. The aberration findings could be adapted to the linear-quadrativ model y = c+ αD + βD 2 . With increasing LET the quantity lambda increased which is a measure for the share of the linear and quadratical components of the dose effect obtained. In case of electrons the RBE-values increased with increasing doses. In the case of neutrons they had their maximum in the low dose range. The feed back distances which lead to formation of primary lesions are for X-rays and electrons approximately 1 μm, for neutrons 1.7 μm. In a fractionation experiment with X-rays, the time of formation of exchange aberrations in radiation-induced primary breaks was measured. The number of dicentric chromosomes decreased with increasing time, while the intercellular distribution was not changed. The number of primary breaks decreasing per temporal interval is proportional to the number of the existing primary breaks. The average feed back time during which the primary breaks lead to induction of dicentric chromosomes, is 110 min. In order to determine the correspondence of the results of in-vivo and in-vitro experiments 15 patients and their blood were irradiated with 60 C-γ-rays. No significant differences were measured. (AJ) [de

  12. Effects of long-term, low dose rate fission neutron irradiation on the peripheral hematological cells in rats

    International Nuclear Information System (INIS)

    Jiang Dingwen; Lei Chengxiang; Shen Xianrong; Ma Li; Yang Xufang; Peng Wulin; Dai Shourong

    2008-01-01

    Objective: To evaluate the effects of long-term, low dose rate fission neutron irradiation on the peripheral hematological cells in rats. Methods: 96 rats were randomly divided into the control group and the irradiation group with low dose rate fission neutron ( 252 Cf, 0.35 mGy/h) irradiation 20.5 h every day. 8 rats of each group were killed at 14 d, 28 d, 42d, 56d, 70d after irradiation and 35d after the irradiation, and their peripheral hematological cells were tested respectively. Results: Compared with the control group, peripheral blood WBC was reduced significantly at the dose of 0.3Gy and 0.4Gy (P < 0.05), and was reduced remarkably at dose of 0.5Gy (P<0.01) and 35d after stopping irradiation(P<0.01). At dose of 0.2Gy, Peripheral blood RBC was abnormally higher comparing with the control group (P<0.01), accompanying with higher HCT and HGB, which suggests condensed blood. At the other point, RBC tend to become lower, but only at dose 0.5Gy, and the difference is significant comparing with control group(P <0.05). At dose of 0.3Gy, 0.4Gy and 0.5Gy, HCT were significantly lower comparing with control group. Comparing with control group, MCV was higher at 35d after stopping irradiation, and PLT was significantly lower in dose of 0.2Gy. Conclusion: Long-term irradiation with low dose rate fission neutron could significantly reduce peripheral blood WBC, with less effects on RBC and PLT. The reduced WBC could not recover at 35d after stopping irradiation. (authors)

  13. Radiation Dose Measurement Using Chemical Dosimeters

    International Nuclear Information System (INIS)

    Lee, Min Sun; Kim, Eun Hee; Kim, Yu Ri; Han, Bum Soo

    2010-01-01

    The radiation dose can be estimated in various ways. Dose estimates can be obtained by either experiment or theoretical analysis. In experiments, radiation impact is assessed by measuring any change caused by energy deposition to the exposed matter, in terms of energy state (physical change), chemical production (chemical change) or biological abnormality (biological change). The chemical dosimetry is based on the implication that the energy deposited to the matter can be inferred from the consequential change in chemical production. The chemical dosimetry usually works on the sample that is an aqueous solution, a biological matter, or an organic substance. In this study, we estimated absorbed doses by quantitating chemical changes in matter caused by radiation exposure. Two different chemical dosimeters, Fricke and ECB (Ethanol-Chlorobenzene) dosimeter, were compared in several features including efficacy as dose indicator and effective dose range

  14. The DNA damage of high doses of X-ray on human peripheral blood nucleated cell's and sperm

    International Nuclear Information System (INIS)

    Wang Hui; Zoulian; Jiang Qisheng; Li Fengsheng; He Rui; Song Xiujun

    2011-01-01

    Objective: To detect the DNA damage of high doses of X-ray on human peripheral blood nucleated cell's and sperm by single cell gel electrophoresis (SCGE). Evaluation the level of DNA damage of human peripheral blood nucleated cell's and sperm after high doses of X-ray. Methods: Using human peripheral blood with normal blood routine and normal sperm,give the dose of 0 Gy, 2 Gy, 4 Gy, 6 Gy, 8 Gy, 10 Gy X-ray radiation with energy of 6MU. Detect the percentage of comet-like tail, tail length and content of DNA in tail of whole blood cell's DNA and sperm's DNA by SCGE technique in 1 hour. Results: The peripheral blood nucleated cell's and sperm's comet rate were 1.00±0.10%, 2.1±1.5%, respectively, have an evidently variance in 0 Gy group (υ=18, t=2.31>1.734, P 1.734, P 1.734, P<0.05). The peripheral blood nucleated cell's and sperm's comet rate were all 100%, 100%, have no-statistical significance in 8 Gy, 10 Gy group. Conclusion: The evidence is powerful enough. That the sperm's SCGE is more sensitive than peripheral blood nucleated cell's SCGE in reflect the X-ray damage in a certain extent (2-6 Gy). (authors)

  15. Peripheral vascular effects on auscultatory blood pressure measurement.

    Science.gov (United States)

    Rabbany, S Y; Drzewiecki, G M; Noordergraaf, A

    1993-01-01

    Experiments were conducted to examine the accuracy of the conventional auscultatory method of blood pressure measurement. The influence of the physiologic state of the vascular system in the forearm distal to the site of Korotkoff sound recording and its impact on the precision of the measured blood pressure is discussed. The peripheral resistance in the arm distal to the cuff was changed noninvasively by heating and cooling effects and by induction of reactive hyperemia. All interventions were preceded by an investigation of their effect on central blood pressure to distinguish local effects from changes in central blood pressure. These interventions were sufficiently moderate to make their effect on central blood pressure, recorded in the other arm, statistically insignificant (i.e., changes in systolic [p cooling experiments was statistically significant (p < 0.001). Moreover, both measured systolic (p < 0.004) and diastolic (p < 0.001) pressure decreases during the reactive hyperemia experiments were statistically significant. The findings demonstrate that alteration in vascular state generates perplexing changes in blood pressure, hence confirming experimental observations by earlier investigators as well as predictions by our model studies.

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  17. Ionization chamber for high dose measurements

    International Nuclear Information System (INIS)

    Rodrigues Junior, Ary de Araujo

    2005-01-01

    Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60 Co gamma source with activity of TBq to P Bq (k Ci to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm 3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60 Co gamma industrial plant. Nitrogen and argon gas at pressure of 10 exp 5 Pa (1 bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma

  18. Effects of low dose rate fission neutron irradiation on the lymphocyte subpopulations of peripheral blood in rats

    International Nuclear Information System (INIS)

    Jiang Dingwen; Lei Chengxiang; Shen Xianrong; Ma Li; Yang Yifang; Peng Wulin; Dai Shourong

    2008-01-01

    Objective: To evaluate the effects of long-term, low dose rate fission neutron irradiation on lymphocyte subpopulations in peripheral blood of rats. Methods: Ninety-six rats were randomly divided into control group and irradiated group exposed to low dose rate fission neutron ( 252 Cf,0.35 mGy/h) for 20.5 h every day. At days 14,28,42,56 and 70 d after irradiation and 35 d after stopping irradiation, After 8 rats of each group were killed, WBC and lymphocyte subpopulations of CD4 + CD3 + , CD8 + CD3 + and CD45RA + /CD161α + in peripheral blood were estimated respectively. Results: Compared with the control group, WBC was reduced significantly at dose of 0.3, 0.4 and 0.5 Gy (P + CD3 - was evidently higher compared with control group at doses of 0.1,0.3, 0.4 and 0.5 Gy and 35 d after stopping irradiation (P + CD3 - was obviously higher compared with control group at dose of 0.2 and 0.3 Gy (P + CD3 + at dose of 0.1 Gy (P + CD3 + at doses of 0.1 and 0.2 Gy (P + CD45RA - ) was increased significantly at doses of 0.2-0.3 Gy, and peripheral blood B cells(CD161α - CD45RA + ) was reduced remarkably at doses of 0.1-0.5 Gy and 35 d after stopping irradiation compared with the control group. Conclusions: Long-term irradiation with low dose rate fission neutron could make TCR (T-cell-receptor) mutant, therefore, WBC, B cells in peripheral blood significantly reduced and NK cells increased. These changes may could not recover at 35 d after Stopping irradiation. (authors)

  19. Peripheral DXA measurement around ankle joint to diagnose osteoporosis as assessed by central DXA measurement.

    Science.gov (United States)

    Sung, Ki Hyuk; Choi, Young; Cho, Gyeong Hee; Chung, Chin Youb; Park, Moon Seok; Lee, Kyoung Min

    2018-02-05

    This study evaluated the correlation between central and peripheral bone mineral density (BMD) of the ankle joint, using dual-energy X-ray absorptiometry (DXA). We also investigated whether peripheral ankle BMD could be used to identify individuals who were diagnosed with osteoporosis, using central DXA. We recruited 134 volunteers aged 20-90 years who agreed to participate in this study. Central BMD of the lumbar spine and left femur, and peripheral BMD of the medial malleolus, distal tibia, lateral malleolus, and talus were measured with DXA. Among the peripheral sites of the ankle, the highest and lowest BMD were observed in the talus and lateral malleolus, respectively. All peripheral DXA measurements of the ankle joint were significantly correlated with central DXA measurements. There was a good correlation (r: 0.656-0.725) between peripheral and central BMD for the older age group (> 50 years), but fair-to-good correlation (r: 0.263-0.654) for the younger age group (ankle joint between osteoporosis and non-osteoporosis were 0.548 g/cm 2 (sensitivity, 89.0%; specificity, 69.0%) for the medial malleolus, 0.626 g/cm 2 (sensitivity, 83.3%; specificity, 82.8%) for the distal tibia, 0.47 g/cm 2 (sensitivity, 100.0%; specificity, 65.5%) for the lateral malleolus, and 0.973 g/cm 2 (sensitivity, 72.2%; specificity, 83.6%) for the talus (p ankle joint and central BMD for older age group. Further study is required to use the ankle DXA as a valid clinical tool for the diagnosis of osteoporosis and fracture risk assessment.

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  1. Surface dose extrapolation measurements with radiographic film

    International Nuclear Information System (INIS)

    Butson, Martin J; Cheung Tsang; Yu, Peter K N; Currie, Michael

    2004-01-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. (note)

  2. Measurements of the personal dose equivalent

    International Nuclear Information System (INIS)

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

    2008-01-01

    Full text: The paper presents the results of measurements related to the personal dose equivalent in the rooms adjacent to NILPRP 7 MeV linear accelerator, by means of the secondary standard chamber T34035 Hp(10). The chamber was calibrated by PTB at S- 137 Cs (E av = 661.6 keV, T 1/2 11050 days) and has N H = 3.17x10 6 Sv/C calibration factor for the personal dose equivalent, Hp(10), at a depth of 10 mm in climatic reference conditions. The measurements were made for the two operation mode of the 7 MeV linac: electrons and bremsstrahlung

  3. Problems in continuous dose rate measurement

    International Nuclear Information System (INIS)

    Yoshioka, Mitsuo

    1983-01-01

    The system of continuous dose rate measurement in Fukui Prefecture is described. A telemeter system was constructed in October, 1976, and it has been operated since 1977. Observation has been made at 11 observation stations in the Prefecture. In addition to the continuous measurement of dose rate by using NaI(T1)-DBM systems, the ionization chambers for high dose rate were installed, and also meteorological data have been collected. The detectors are covered with 1 mm thick aluminum designed so that the absorption of external radiation is kept as small as possible. To keep the environmental temperature of the detectors constant, constant temperature wind blow is made. With these consideration, the measurement of Xe-133 is possible, and the standard deviation of yearly dose is around 0.4 mR/Y. By measuring DBM transmission rate, the contribution of Xe-133, which comes from the exhaust pumps in power plants, can be detected. The problems of this system are as follows. First of all, the characteristics of the system must meet the purpose of dose monitoring. The system must detect the dose less than the target value to be achieved. The second is the selection of measuring systems to be set. The system is still not unified, and it is difficult to exchange data between different stations. Finally, the method of data analysis is not yet unified. Manuals or guide-books for this purpose are necessary for the mutual comparison of the data from the stations in different districts. (Kato, T.)

  4. Early morphologic and quantitative changes in mouse peripheral blood lymphocytes after low dose gamma-irradiation

    International Nuclear Information System (INIS)

    Gitsov, L.; Byrneva, V.; Goranov, I.

    1979-01-01

    The study was undertaken in an effort to establish differences in the radiosensitivity of peripheral blood lymphocytes, as a possible test for evaluation of early and discrete radiation injury. Sexually mature mice of BAIB/c line were X-irradiated with doses of 50 and 250 rad. The animals were sacrificed by blood letting 24 hours after irradiation, but 30 minutes before this each mouse was heparinized. Smears were prepared from the enriched pooled leucocyte suspensions, obtained by dextran sedimentation of the red cells. The preparations were stained with toluidin blue by the methods of Smetana and Pappenheim. Cell size, clasmatosis, nucleolar structure and degree of cytoplasmic metachromasia were determined. It was found that the lymphocytogram of animals irradiated with 50 rad was characterized by high percentage of small lymphocytes, most of them with dispersed nuclear ribonucleoproteins and minimal clasmatose activity. Irradiation with 100 rad induced a characteristical rise in lymphocyte clasmatose activity and decrease in the number of small lymphocytes. The nucleoli were bright and well delineated. The lymphocytogram of animals irradiated with higher doses (150 and 250 rad) was characterized by predomination of large lymphocytes and hyperbasophilic forms with well preserved bright nucleoli. The percentage of lymphocates with clasmatosis was below the control value. (A.B.)

  5. Measuring pacemaker dose: A clinical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Studenski, Matthew T., E-mail: matthew.studenski@jeffersonhospital.org [Department of Radiation Oncology at the Jefferson Medical College and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA (United States); Xiao Ying; Harrison, Amy S. [Department of Radiation Oncology at the Jefferson Medical College and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA (United States)

    2012-07-01

    Recently in our clinic, we have seen an increased number of patients presenting with pacemakers and defibrillators. Precautions are taken to develop a treatment plan that minimizes the dose to the pacemaker because of the adverse effects of radiation on the electronics. Here we analyze different dosimeters to determine which is the most accurate in measuring pacemaker or defibrillator dose while at the same time not requiring a significant investment in time to maintain an efficient workflow in the clinic. The dosimeters analyzed here were ion chambers, diodes, metal-oxide-semiconductor field effect transistor (MOSFETs), and optically stimulated luminescence (OSL) dosimeters. A simple phantom was used to quantify the angular and energy dependence of each dosimeter. Next, 8 patients plans were delivered to a Rando phantom with all the dosimeters located where the pacemaker would be, and the measurements were compared with the predicted dose. A cone beam computed tomography (CBCT) image was obtained to determine the dosimeter response in the kilovoltage energy range. In terms of the angular and energy dependence of the dosimeters, the ion chamber and diode were the most stable. For the clinical cases, all the dosimeters match relatively well with the predicted dose, although the ideal dosimeter to use is case dependent. The dosimeters, especially the MOSFETS, tend to be less accurate for the plans, with many lateral beams. Because of their efficiency, we recommend using a MOSFET or a diode to measure the dose. If a discrepancy is observed between the measured and expected dose (especially when the pacemaker to field edge is <10 cm), we recommend analyzing the treatment plan to see whether there are many lateral beams. Follow-up with another dosimeter rather than repeating multiple times with the same type of dosimeter. All dosimeters should be placed after the CBCT has been acquired.

  6. Radiation dose measurement in gastrointestinal studies

    International Nuclear Information System (INIS)

    Sulieman, A.; Elzaki, M.; Kappas, C.; Theodorou, K.

    2011-01-01

    Barium studies investigations (barium swallow, barium meal and barium enema) are the basic routine radiological examination, where barium sulphate suspension is introduced to enhance image contrast of gastrointestinal tracts. The aim of this study was to quantify the patients' radiation doses during barium studies and to estimate the organ equivalent dose and effective dose with those procedures. A total of 33 investigations of barium studies were measured by using thermoluminescence dosemeters. The result showed that the patient entrance surface doses were 12.6±10, 44.5±49 and 35.7±50 mGy for barium swallow, barium meal, follow through and enema, respectively. Effective doses were 0.2, 0.35 and 1.4 mSv per procedure for barium swallow, meal and enema respectively. Radiation doses were comparable with the previous studies. A written protocol for each procedure will reduce the inter-operator variations and will help to reduce unnecessary exposure. (authors)

  7. Measurement and evaluation of internal dose

    International Nuclear Information System (INIS)

    Lee, Tae Young; Chang, S. Y.; Lee, J. I.; Song, M. Y.

    2006-01-01

    This report describes the contents and results for implementation of internal radiation monitoring programme, measurement of uranium present in lung by lung counter and assessment of committed effective dose for radiation workers of the KNFC. The aim of radiation protection was achieved by implementing this activity

  8. Polystyrene calorimeter for electron beam dose measurements

    DEFF Research Database (Denmark)

    Miller, A.

    1995-01-01

    Calorimeters from polystrene have been constructed for dose measurement at 4-10 MeV electron accelerators. These calorimeters have been used successfully for a few years, and polystyrene calorimeters for use at energies down to 1 MeV and being tested. Advantage of polystyrene as the absorbing...

  9. Low-Dose Pulsatile Interleukin-6 As a Treatment Option for Diabetic Peripheral Neuropathy

    Directory of Open Access Journals (Sweden)

    Gautam Ghatnekar

    2017-05-01

    Full Text Available Diabetic peripheral neuropathy (DPN remains one of the most common and serious complications of diabetes. Currently, pharmacological agents are limited to treating the pain associated with DPN, and do not address the underlying pathological mechanisms driving nerve damage, thus leaving a significant unmet medical need. Interestingly, research conducted using exercise as a treatment for DPN has revealed interleukin-6 (IL-6 signaling to be associated with many positive benefits such as enhanced blood flow and lipid metabolism, decreased chronic inflammation, and peripheral nerve fiber regeneration. IL-6, once known solely as a pro-inflammatory cytokine, is now understood to signal as a multifunctional cytokine, capable of eliciting both pro- and anti-inflammatory responses in a context-dependent fashion. IL-6 released from muscle in response to exercise signals as a myokine and as such has a unique kinetic profile, whereby levels are transiently elevated up to 100-fold and return to baseline levels within 4 h. Importantly, this kinetic profile is in stark contrast to long-term IL-6 elevation that is associated with pro-inflammatory states. Given exercise induces IL-6 myokine signaling, and exercise has been shown to elicit numerous beneficial effects for the treatment of DPN, a causal link has been suggested. Here, we discuss both the clinical and preclinical literature related to the application of IL-6 as a treatment strategy for DPN. In addition, we discuss how IL-6 may directly modulate Schwann and nerve cells to explore a mechanistic understanding of how this treatment elicits a neuroprotective and/or regenerative response. Collectively, studies suggest that IL-6, when administered in a low-dose pulsatile strategy to mimic the body’s natural response to exercise, may prove to be an effective treatment for the protection and/or restoration of peripheral nerve function in DPN. This review highlights the studies supporting this assertion and

  10. Measurements of dose with individual FAMOS transistors

    Energy Technology Data Exchange (ETDEWEB)

    Scheick, L.Z.; McNulty, P.J.; Roth, D.R.; Davis, M.G.; Mason, B.E.

    1999-12-01

    A new method is described for measuring the doses absorbed by microstructures from an exposure to ionizing radiation. The decrease in the duration of UltraViolet light (UV) exposure required to erase each cell of a commercial UltraViolet erasable Programmable Read Only Memory (UVPROM) correlates with the dose absorbed by the floating gate of that transistor. This technique facilitates analysis of the microdose distribution across the array and the occurrence of Single Event Upset (SEU) like anomalous shifts due to rare large energy-deposition events.

  11. Measurements of dose with individual FAMOS transistors

    International Nuclear Information System (INIS)

    Scheick, L.Z.; McNulty, P.J.; Roth, D.R.; Davis, M.G.; Mason, B.E.

    1999-01-01

    A new method is described for measuring the doses absorbed by microstructures from an exposure to ionizing radiation. The decrease in the duration of UltraViolet light (UV) exposure required to erase each cell of a commercial UltraViolet erasable Programmable Read Only Memory (UVPROM) correlates with the dose absorbed by the floating gate of that transistor. This technique facilitates analysis of the microdose distribution across the array and the occurrence of Single Event Upset (SEU) like anomalous shifts due to rare large energy-deposition events

  12. 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

  13. A dose-effect curve of premature condensation chromosome ring in lymphocytes of human peripheral blood exposed to high dose of 60Co γ-rays in vitro

    International Nuclear Information System (INIS)

    Yao Bo; Li Yufang; Liu Guangxian; Huang Shan; Jiang Benrong; Ai Huisheng

    2009-01-01

    Objective: To establish a dose-effect curve of premature condensation chromosome ring (PCC-R) in lymphocytes of human peripheral blood after exposed to high doses of γ-rays. Methods: Peripheral blood samples was drawn from three healthy individuals, and exposed to 60 Co γ-rays with doses between 0 and 30 Gy. The frequencies of PCC-R in premature condensation chromosome (PCC) cells obtained by Okadaic acid (OA) induction were calculated, and a dose-effect curve was fitted. Results: PCC index tapered with dose. Frequencies of PCC-R per cell increased until 20 Gy, and then saturation was observed. The results were fitted to a lineal model up to 20 Gy: y=-0.020 + 0.052D, where y was the frequencies of PCC-R per cell, D was the radiation dose(Gy). Conclusions: The highest dose could be estimated is 20 Gy by the dose-effect curve established with PCC-R method. Its utility and validity will be verified in the future application of radiation accident. (authors)

  14. Electrophysiological measurements of diabetic peripheral neuropathy: A systematic review.

    Science.gov (United States)

    Shabeeb, Dheyauldeen; Najafi, Masoud; Hasanzadeh, Gholamreza; Hadian, Mohammed Reza; Musa, Ahmed Eleojio; Shirazi, Alireza

    2018-03-28

    Peripheral neuropathy is one of the main complications of diabetes mellitus. One of the features of diabetic nerve damage is abnormality of sensory and motor nerve conduction study. An electrophysiological examination can be reproduced and is also a non-invasive approach in the assessment of peripheral nerve function. Population-based and clinical studies have been conducted to validate the sensitivity of these methods. When the diagnosis was based on clinical electrophysiological examination, abnormalities were observed in all patients. In this research, using a review design, we reviewed the issue of clinical electrophysiological examination of diabetic peripheral neuropathy in articles from 2008 to 2017. For this purpose, PubMed, Scopus and Embase databases of journals were used for searching articles. The researchers indicated that diabetes (both types) is a very disturbing health issue in the modern world and should be given serious attention. Based on conducted studies, it was demonstrated that there are different procedures for prevention and treatment of diabetes-related health problems such as diabetic polyneuropathy (DPN). The first objective quantitative indication of the peripheral neuropathy is abnormality of sensory and motor nerve conduction tests. Electrophysiology is accurate, reliable and sensitive. It can be reproduced and also is a noninvasive approach in the assessment of peripheral nerve function. The methodological review has found that the best method for quantitative indication of the peripheral neuropathy compared with all other methods is clinical electrophysiological examination. For best results, standard protocols such as temperature control and equipment calibration are recommended. Copyright © 2018. Published by Elsevier Ltd.

  15. Prostaglandin E1 in conjunction with high doses of vitamin B12 improves nerve conduction velocity of patients with diabetic peripheral neuropathy

    Institute of Scientific and Technical Information of China (English)

    Jilai Li; Zhirong Wan

    2008-01-01

    BACKGROUND: Prostaglandin E1 improves diabetic peripheral neuropathy in symptoms and sensory threshold. Vitamin B1 and methyl-vitamin B12 improve microcirculation to peripheral nerve tissue and promote neurotrophy.OBJECTIVE: To observe motor nerve and sensory nerve conduction velocity in patients with diabetic peripheral neuropathy, prior to and after treatment with prostaglandin E1, vitamin B1 and different doses of vitamin B12.DESIGN, TIME AND SETTING: Randomized, controlled experiment, performed at the Department of Neurology. Beijing Hantian Central Hospital, between February 2002 and September 2007.PARTICIPANTS: A total of 122 patients with type 2 diabetic peripheral neuropathy; 73 males and 49 females were included. All patients met the diagnostic criteria of diabetes mellitus, as determined by the World Health Organization in 1999 and 2006, and also the diagnostic criteria of diabetic peripheral neuropathy. For each subject, conduction disorders in the median nerve and in the common peroneal nerve were observed using electromyogram. Also, after diet and drug treatment, the blood glucose level of subjects was observed to be at a satisfactory level for more than two weeks, and the symptoms of diabetic peripheral neuropathy were not alleviated.METHODS: All patients were randomly divided into the following three groups. A control group (n=40), in which, 100mg vitamin B1 and 500μg vitamin B12 were intramuscularly injected. A vitamin B12 low-dose treated group (n=42), in which 10μg prostaglandin E1 in 250mL physiological saline was intravenously injected once a day and 100mg vitamin B1 and 500μg vitamin B12 was intramuscularly injected once a day. Lastly, a vitamin B12 high-dose treated group (n=40), in which administration was the same as in the vitamin B12 low-dose treated group, except that 500μg vitamin B12 was replaced by 1mg vitamin B12. Administration was performed for four weeks for each group.MAIN OUTCOME MEASURES: The motor nerve and sensory nerve

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

    International Nuclear Information System (INIS)

    McLaughlin, W.L.

    1985-01-01

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

  17. Individual radiation therapy patient whole-body phantoms for peripheral dose evaluations: method and specific software

    International Nuclear Information System (INIS)

    Alziar, I; Vicente, C; Giordana, G; Ben-Harrath, O; De Vathaire, F; Diallo, I; Bonniaud, G; Couanet, D; Chavaudra, J; Lefkopoulos, D; Ruaud, J B; Diaz, J C; Grandjean, P; Kafrouni, H

    2009-01-01

    This study presents a method aimed at creating radiotherapy (RT) patient-adjustable whole-body phantoms to permit retrospective and prospective peripheral dose evaluations for enhanced patient radioprotection. Our strategy involves virtual whole-body patient models (WBPM) in different RT treatment positions for both genders and for different age groups. It includes a software tool designed to match the anatomy of the phantoms with the anatomy of the actual patients, based on the quality of patient data available. The procedure for adjusting a WBPM to patient morphology includes typical dimensions available in basic auxological tables for the French population. Adjustment is semi-automatic. Because of the complexity of the human anatomy, skilled personnel are required to validate changes made in the phantom anatomy. This research is part of a global project aimed at proposing appropriate methods and software tools capable of reconstituting the anatomy and dose evaluations in the entire body of RT patients in an adapted treatment planning system (TPS). The graphic user interface is that of a TPS adapted to obtain a comfortable working process. Such WBPM have been used to supplement patient therapy planning images, usually restricted to regions involved in treatment. Here we report, as an example, the case of a patient treated for prostate cancer whose therapy planning images were complemented by an anatomy model. Although present results are preliminary and our research is ongoing, they appear encouraging, since such patient-adjusted phantoms are crucial in the optimization of radiation protection of patients and for follow-up studies. (note)

  18. Individual radiation therapy patient whole-body phantoms for peripheral dose evaluations: method and specific software.

    Science.gov (United States)

    Alziar, I; Bonniaud, G; Couanet, D; Ruaud, J B; Vicente, C; Giordana, G; Ben-Harrath, O; Diaz, J C; Grandjean, P; Kafrouni, H; Chavaudra, J; Lefkopoulos, D; de Vathaire, F; Diallo, I

    2009-09-07

    This study presents a method aimed at creating radiotherapy (RT) patient-adjustable whole-body phantoms to permit retrospective and prospective peripheral dose evaluations for enhanced patient radioprotection. Our strategy involves virtual whole-body patient models (WBPM) in different RT treatment positions for both genders and for different age groups. It includes a software tool designed to match the anatomy of the phantoms with the anatomy of the actual patients, based on the quality of patient data available. The procedure for adjusting a WBPM to patient morphology includes typical dimensions available in basic auxological tables for the French population. Adjustment is semi-automatic. Because of the complexity of the human anatomy, skilled personnel are required to validate changes made in the phantom anatomy. This research is part of a global project aimed at proposing appropriate methods and software tools capable of reconstituting the anatomy and dose evaluations in the entire body of RT patients in an adapted treatment planning system (TPS). The graphic user interface is that of a TPS adapted to obtain a comfortable working process. Such WBPM have been used to supplement patient therapy planning images, usually restricted to regions involved in treatment. Here we report, as an example, the case of a patient treated for prostate cancer whose therapy planning images were complemented by an anatomy model. Although present results are preliminary and our research is ongoing, they appear encouraging, since such patient-adjusted phantoms are crucial in the optimization of radiation protection of patients and for follow-up studies.

  19. Usefulness assessment of secondary shield for the lens exposure dose reduction during radiation treatment of peripheral orbit

    International Nuclear Information System (INIS)

    Kwak, Yong Kuk; Hong, Sun Gi; Ha, Min Yong; Park, Jang Pil; Yoo, Sook Hyun; Cho, Woong

    2015-01-01

    This study presents the usefulness assessment of secondary shield for the lens exposure dose reduction during radiation treatment of peripheral orbit. We accomplished IMRT treatment plan similar with a real one through the computed treatment planning system after CT simulation using human phantom. For the secondary shield, we used Pb plate (thickness 3mm, diameter 25mm) and 3 mm tungsten eye-shield block. And we compared lens dose using OSLD between on TPS and on simulation. Also, we irradiated 200 MU(6 MV, SPD(Source to Phantom Distance)=100 cm, F·S 5×5 cm)on a 5 cm acrylic phantom using the secondary shielding material of same condition, 3 mm Pb and tungsten eye-shield block. And we carried out the same experiment using 8 cm Pb block to limit effect of leakage and transmitted radiation out of irradiation field. We attached OSLD with a 1cm away from the field at the side of phantom and applied a 3mm bolus equivalent to the thickness of eyelid. Using human phantom, the Lens dose on IMRT treatment plan is 315.9 cGy and the real measurement value is 216.7 cGy. And after secondary shield using 3mm Pb plate and tungsten eye-shield block, each lens dose is 234.3, 224.1 cGy. The result of a experiment using acrylic phantom, each value is 5.24, 5.42 and 5.39 cGy in case of no block, 3mm Pb plate and tungsten eye-shield block. Applying O.S.B out of the field, each value is 1.79, 2.00 and 2.02 cGy in case of no block, 3 mm Pb plate and tungsten eye-shield block. When secondary shielding material is used to protect critical organ while irradiating photon, high atomic number material (like metal) that is near by critical organ can be cause of dose increase according to treatment region and beam direction because head leakage and collimator and MLC transmitted radiation are exist even if it's out of the field. The attempt of secondary shield for the decrease of exposure dose was meaningful, but untested attempt can have a reverse effect. So, a preliminary inspection

  20. Dose Assessment using Chromosome Aberration Analyses in Human Peripheral Blood Lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin-Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The healthy five donors were recruited to establish the dose-response calibration curve for chromosomal aberrations by ionizing radiation exposure. Our cytogenetic results revealed that the mean frequency of chromosome aberration increased with increasing radiation dose. In this study, dicentric assay and CBMN assay were compared considering the sensitivity and accuracy of dose estimation. Therefore, these chromosome aberration analyses will be the foundation for biological dosimetric analysis with additional research methods such as translocation and PCC assay. The conventional analysis of dicentric chromosomes in HPBL was suggested by Bender and Gooch in 1962. This assay has been for many years, the golden standard and the most specific method for ionizing radiation damage. The dicentric assay technique in HPBL has been shown as the most sensitive biological method and reliable bio-indicator of quantifying the radiation dose. In contrast, the micronucleus assay has advantages over the dicentric assay since it is rapid and requires less specialized expertise, and accordingly it can be applied to monitor a big population. The cytokinesis-block micronucleus (CBMN) assay is a suitable method for micronuceli measurement in cultured human as well as mammalian cells. The aim of our study was to establish the dose response curve of radiation-induced chromosome aberrations in HPBL by analyzing the frequency of dicentrics and micronuclei.

  1. The peripheral artery questionnaire: a new disease-specific health status measure for patients with peripheral arterial disease.

    Science.gov (United States)

    Spertus, John; Jones, Philip; Poler, Sherri; Rocha-Singh, Krishna

    2004-02-01

    The most common indication for treating patients with peripheral arterial disease is to improve their health status: their symptoms, function, and quality of life. Quantifying health status requires a valid, reproducible, and sensitive disease-specific measure. The Peripheral Artery Questionnaire (PAQ) is a 20-item questionnaire developed to meet this need by quantifying patients' physical limitations, symptoms, social function, treatment satisfaction, and quality of life. Psychometric and clinical properties of the PAQ were evaluated in a prospective cohort study of 44 patients undergoing elective percutaneous peripheral revascularization. To establish reproducibility, 2 assessments were performed 2 weeks apart and before revascularization. The change in scores before and 6 weeks after revascularization were used to determine the instruments' responsiveness and were compared with the Short Form-36 and the Walking Impairment Questionnaire. A series of cross-sectional analyses were performed to establish the construct validity of the PAQ. The 7 domains of the PAQ were internally reliable, with Cronbach alpha = 0.80 to 0.94. The test-retest reliability analyses revealed insignificant mean changes of 0.6 to 2.3 points (P = not significant for all). Conversely, the change after revascularization ranged from 13.7 to 41.9 points (P PAQ to clinical improvement. The PAQ Summary Scale was the most sensitive of all scales tested. Construct validity was established by demonstrating correlations with other measures of patient health status. The PAQ is a valid, reliable, and responsive disease-specific measure for patients with peripheral arterial disease. It may prove to be a useful end point in clinical trials and a potential aid in disease management.

  2. Patient and personnel dose measurements at selective coronarangiography

    International Nuclear Information System (INIS)

    Maripuu, E.

    1977-01-01

    During 1975 dose measurements were performed on patients and doctors at the thoraxradiologic department of the Caroline Hospital in Stockholm, Sweden. The doses were measured during angiography. Skin doses are listed in tables. Also the doses to the bone marrow was estimated. LiF-dosemeters were used for the measurements. Calibration of the dosemeters and errors in the measurements are discussed

  3. Impact of a Low CD34+ Cell Dose on Allogeneic Peripheral Blood Stem Cell Transplantation.

    Science.gov (United States)

    Yamamoto, Chihiro; Ogawa, Hiroyasu; Fukuda, Takahiro; Igarashi, Aiko; Okumura, Hirokazu; Uchida, Naoyuki; Hidaka, Michihiro; Nakamae, Hirohisa; Matsuoka, Ken-Ichi; Eto, Tetsuya; Ichinohe, Tatsuo; Atsuta, Yoshiko; Kanda, Yoshinobu

    2018-04-01

    Although the CD34 + cell dose in allogeneic peripheral blood stem cell transplantation (PBSCT) is considered to be associated with transplantation outcomes, a lower acceptable threshold has not been defined. We retrospectively analyzed 2919 adult patients with hematologic malignancies who underwent related PBSCT in Japan between 2001 and 2014. According to the number of CD34 + cells in the graft, we categorized 2494 patients in the standard group (2 to 5 × 10 6 cells/kg), 377 patient in the low group (1 to 2 × 10 6 cells/kg), and 48 patients in the very low group (<1 × 10 6 cells/kg). Compared with the standard group, the low and very low groups showed delayed neutrophil recovery (93.8%, 89.5%, and 78.3%, respectively at day +28; P < .001) and platelet recovery (69.3%, 53.0%, and 45.5%, respectively at day +28; P < .001). The 2-year overall survival (OS) in the 3 groups was 45.5%, 45.3%, and 29.8%, respectively, with inferior survival in the very low group. However, a higher percentage of high-risk patients may account for the inferior survival in the very low group, and no significant difference in OS was found in a multivariate analysis. There were no differences in relapse, nonrelapse mortality, or the development of graft-versus-host disease among the 3 groups. In conclusion, allogeneic PBSCT with low CD34 + cell doses of 1 to 2 × 10 6 cells/kg gives acceptable results, whereas further investigations are needed to evaluate the effects of lower doses of <1 × 10 6 cells/kg owing to the smaller number and the higher percentage of patients with adverse prognostic factors in this cohort. Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

  4. New sonographic measures of peripheral nerves: a tool for the diagnosis of peripheral nerve involvement in leprosy

    Directory of Open Access Journals (Sweden)

    Marco Andrey Cipriani Frade

    2013-05-01

    Full Text Available To evaluate ultrasonographic (US cross-sectional areas (CSAs of peripheral nerves, indexes of the differences between CSAs at the same point (∆CSAs and between tunnel (T and pre-tunnel (PT ulnar CSAs (∆TPTs in leprosy patients (LPs and healthy volunteers (HVs. Seventy-seven LPs and 49 HVs underwent bilateral US at PT and T ulnar points, as well as along the median (M and common fibular (CF nerves, to calculate the CSAs, ∆CSAs and ∆TPTs. The CSA values in HVs were lower than those in LPs (p 80% and ∆TPT had the highest specificity (> 90%. New sonographic peripheral nerve measurements (∆CSAs and ∆TPT provide an important methodological improvement in the detection of leprosy neuropathy.

  5. Hydrogen gas production is associated with reduced interleukin-1β mRNA in peripheral blood after a single dose of acarbose in Japanese type 2 diabetic patients.

    Science.gov (United States)

    Tamasawa, Atsuko; Mochizuki, Kazuki; Hariya, Natsuyo; Saito, Miyoko; Ishida, Hidenori; Doguchi, Satako; Yanagiya, Syoko; Osonoi, Takeshi

    2015-09-05

    Acarbose, an α-glucosidase inhibitor, leads to the production of hydrogen gas, which reduces oxidative stress. In this study, we examined the effects of a single dose of acarbose immediately before a test meal on postprandial hydrogen gas in breath and peripheral blood interleukin (IL)-1β mRNA expression in Japanese type 2 diabetic patients. Sixteen Japanese patients (14 men, 2 women) participated in this study. The mean±standard deviation age, hemoglobin A1c and body mass index were 52.1±15.4 years, 10.2±2.0%, and 27.7±8.0kg/m(2), respectively. The patients were admitted into our hospital for 2 days and underwent test meals at breakfast without (day 1) or with acarbose (day 2). We performed continuous glucose monitoring and measured hydrogen gas levels in breath, and peripheral blood IL-1β mRNA levels before (0min) and after the test meal (hydrogen gas: 60, 120, 180, and 300min; IL-1β: 180min). The induction of hydrogen gas production and the reduction in peripheral blood IL-1β mRNA after the test meal were not significant between days 1 (without acarbose) and 2 (with acarbose). However, the changes in total hydrogen gas production from day 1 to day 2 were closely and inversely associated with the changes in peripheral blood IL-1β mRNA levels. Our results suggest that an increase in hydrogen gas production is inversely associated with a reduction of the peripheral blood IL-1β mRNA level after a single dose of acarbose in Japanese type 2 diabetic patients. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. SU-E-T-611: Photon and Neutron Peripheral Dose Ratio for Low (6 MV) and High (15 MV) Energy for Treatment Selection

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L; Sanchez-Doblado, F [Departamento de Fisiologia Medica y Biofisica, Universidad de Seville (Spain); Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Seville (Spain); Terron, J; Ortiz-Seidel, M [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Seville (Spain); Departamento de Fisiologia Medica y Biofisica, Universidad de Seville (Spain); Sanchez-Nieto, B [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago (Chile)

    2015-06-15

    Purpose: Differences between radiotherapy techniques and energies, can offer improvements in tumor coverage and organs at risk preservation. However, a more complete decision should include peripheral doses delivered to the patient. The purpose of this work is the balance of photon and neutron peripheral doses for a prostate case solved with 6 different treatment modalities. Methods: Inverse and Forward IMRT and 3D-CRT in 6 and 15 MV for a Siemens Primus linac, using the same CT data set and contours. The methodology described in [1], was used with the TNRD thermal neutron detector [2] for neutron peripheral dose estimation at 7 relevant organs (colon, esophagus, stomach, liver, lung, thyroid and skin). Photon doses were estimated for these organs by terms of the algorithm proposed in [3]. Plans were optimized with the same restrictions and limited to 30 segments in the Inverse case. Results: A similar photon peripheral dose was found comparing 6 and 15 MV cases with slightly higher values of (1.9 ± 1.6) % in mean, for the 6 MV cases. Neutron presence when using 15 MV, represents an increase in peripheral dose of (18 ± 17) % in average. Due to the higher number of MU used in Inverse IMRT, an increasing of (22 ± 3) % in neutron dose is found related to Forward and 3D-CRT plans. This corresponds to photon doses within 44 and 255 mSv along the organs, for a dose prescription of 68 Gy at the isocenter. Conclusion: Neutron and photon peripheral doses for a prostate treatment planified in 6 different techniques have been analyzed. 6 MV plans are slightly more demanding in terms of photon peripheral doses. Inverse technique in 15 MV has Result to be the most demanding one in terms of total peripheral doses, including neutrons and photons.

  7. Effect of low dose irradiation on subsets of T-lymphocyte of peripheral blood, spleen and tumor tissue

    International Nuclear Information System (INIS)

    Zou Huawei; Su Liaoyuan; Tian Hailin

    1998-01-01

    Purpose: In order to understand the mechanism of the stimulation effects of low dose radiation (LDR), the author observed the immune changes of T-lymphocyte subsets. Meteria and methods: Whole body of BALB/C bring-tumor mice were exposed to the doses of 5, 10, 20 and 50 cGy γ-rays. The changes of T-lymphocyte subsets in peripheral blood, spleen and tumor-infiltrating lymphocyte (TIL) were studied with flow cytometry (FCM). Results: the ratio of L 3 T 4 + /Lyt 2 + remarkable increased in the peripheral blood and spleen (p 3 T 4 + /Lyt 2 + further decreased in the TIL group of mice exposed 10 cGy (p 2 + molecules, were concentrated in the tumor tissues and they carried out the killing function to the tumor cells

  8. Vessel diameter measurements in gadolinium contrast-enhanced three-dimensional MRA of peripheral arteries

    NARCIS (Netherlands)

    Westenberg, J.J.M.; Geest, van der R.J.; Wasser, M.N.J.M.; Linden, van der E.L.; Walsum, van T.; Assen, van H.C.; Roos, de A.; Vanderschoot, J.; Reiber, J.H.C.

    2000-01-01

    In this study, the possibilities for quantification of vessel diameters of peripheral arteries in gadolinium contrast-enhanced magnetic resonance angiography (Gd CE MRA) were evaluated. Absolute vessel diameter measurements were assessed objectively and semi-automatically in maximum intensity

  9. Sensitivity of human peripheral lymphocyte chromosomes to various X-ray doses and subsequent storage in Plexiglass or glass containers

    International Nuclear Information System (INIS)

    Ivanov, B.; Bulanova, M.; Geogieva, I.

    1979-01-01

    A study was performed to determine whether chromosomal aberrations produced in vitro by various X-ray doses in human lymphocytes were affected by post-irradiation storage of the blood in plastic or glass containers. Following X-ray doses of up to 400 R, the yields of cells with aberrations and the incidence of dicentrics, rings, interstitial deletions, symmetrical changes and chromosome fragments increased with dose. After storage of the irradiated lymphocytes in either Plexiglass or glass, the values for exchange aberrations, deletions and aberrant cells were compared. The only statistically significant difference was a slight increase in the percentage of aberrant cells stored in the plastic containers at the 400 R dose level. It was concluded that plastics appear to have a sensitizing effect on the genetic structure of the peripheral lymphocyte and thus the use of this material to store blood in biological dosimetry studies should be discouraged. (U.K.)

  10. Simple Radiowave-Based Method For Measuring Peripheral Blood Flow Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    Project objective is to design small radio frequency based flow probes for the measurement of blood flow velocity in peripheral arteries such as the femoral artery and middle cerebral artery. The result will be the technological capability to measure peripheral blood flow rates and flow changes during various environmental stressors such as microgravity without contact to the individual being monitored. This technology may also lead to an easier method of detecting venous gas emboli during extravehicular activities.

  11. Dose rate measuring device and dose rate measuring method using the same

    International Nuclear Information System (INIS)

    Urata, Megumu; Matsushita, Takashi; Hanazawa, Sadao; Konno, Takahiro; Chiba, Yoshinori; Yumitate, Tadahiro

    1998-01-01

    The device of the present invention comprises a scintillation fiber scope having a shape elongated in the direction of the height of a pressure vessel and emitting light by incident of radiation to detect radiation, a radioactivity measuring device for measuring a dose rate based on the detection of the fiber scope and a reel means for dispensing and taking up the fiber scope, and it constituted such that the dose rate of the pressure vessel and that of a shroud are determined independently. Then, when the taken out shroud is contained in an container, excessive shielding is not necessary, in addition, this device can reliably be inserted to or withdrawn from complicated places between the pressure vessel and the shroud, and further, the dose rate of the pressure vessel and that of the shroud can be measured approximately accurately even when the thickness of them is different greatly. (N.H.)

  12. Dose rate measuring device and dose rate measuring method using the same

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Megumu; Matsushita, Takashi; Hanazawa, Sadao; Konno, Takahiro; Chiba, Yoshinori; Yumitate, Tadahiro

    1998-11-13

    The device of the present invention comprises a scintillation fiber scope having a shape elongated in the direction of the height of a pressure vessel and emitting light by incident of radiation to detect radiation, a radioactivity measuring device for measuring a dose rate based on the detection of the fiber scope and a reel means for dispensing and taking up the fiber scope, and it constituted such that the dose rate of the pressure vessel and that of a shroud are determined independently. Then, when the taken out shroud is contained in an container, excessive shielding is not necessary, in addition, this device can reliably be inserted to or withdrawn from complicated places between the pressure vessel and the shroud, and further, the dose rate of the pressure vessel and that of the shroud can be measured approximately accurately even when the thickness of them is different greatly. (N.H.)

  13. Induction and persistence of multicentric chromosomes in cultured human peripheral blood lymphocytes following high-dose gamma irradiation

    International Nuclear Information System (INIS)

    Suto, Yumiko; Hirai, Momoki; Akiyama, Miho; Nakagawa, Takashi; Tominaga, Takako; Suzuki, Toshikazu; Sugiura, Nobuyuki; Yuki, Masanori; Nakayama, Fumiaki

    2012-01-01

    Among radiation-induced chromosome aberrations, multicentric chromosomes, as represented by dicentric chromosomes (dicentrics), are regarded as sensitive and specific biomarkers for assessing radiation dose in the 0 to 5 Gy range. The objective of this study was to characterize chromosome aberrations induced in vitro by a higher dose of radiation. Peripheral blood lymphocytes were exposed to 15 Gy gamma rays at a dose rate of 0.5 Gy/min and harvested at 48, 50, 52, 54, 56 and 72 h. The first mitotic peak appeared at 52-54 h, showing about a 6 h mitotic delay as compared with nonirradiated control cultures. Cell-cycle analysis of parallel and simultaneous cultures by sister-chromatid differentiation staining suggests that metaphase cells examined in 48-56 h cultures were in the first mitosis after culture initiation. The mean dicentric equivalent counts ranged from 9.0 to 9.3 in consecutively harvested cultures with no significant differences among them. At 72 h, about 20% of dividing cells were tetraploid, persisting with faithfully replicated unstable chromosome aberrations. The non-random distribution of replicated chromosome pairs, deduced from multicolor fluorescence in situ hybridization analysis, led us to surmise that the predominant mechanism underlying the induction of tetraploid cells is endoreduplication. These findings suggest that a high-dose in vitro irradiation applied to peripheral blood lymphocytes may affect on the replication process, in addition to structural chromosome damage. (author)

  14. Influence of radiation-dose pattern from inhaled beta--gamma-emitting radionuclides on canine peripheral lymphocytes

    International Nuclear Information System (INIS)

    Jones, R.K.; Boecker, B.B.; Pickrell, J.A.; Hobbs, C.H.; McClellan, R.O.

    1976-01-01

    As part of studies assess the biological hazards associated with inhaled radionuclides, periodic hematologic evaluations were performed on beagle dogs given a single nose-only exposure to aerosols of beta--gamma-emitting isotopes. The physical form and specific radionuclides selected produced radiation-dose patterns representative of those which might be encountered in the event of human accidental exposures. Dogs received graded lung burdens of either 90 Y, 91 Y, 144 Ce, or 90 Sr, each in fused clay. Differences in the effective half-lives of these radionuclides resulted in a spectrum of cumulative radiation doses to lung delivered at a variety of dose rates. Since the form in which the radionuclides were inhaled was relatively insoluble, the lung and intrathoracic tissues represented the primary recipient of the dose. Regardless of the effective half-life of radionuclide retention, a dose-related depression of peripheral lymphocytes was observed at various times after inhalation exposure. The time at which maximum depression and subsequent recovery occurred, however, was most directly related to the effective half-life of the radionuclide. Of special interest was the persistence of lymphopenia through 2 1 / 2 years after exposure to 144 Ce and 90 Sr in fused clay where, other than tracheobronchial lymph nodes, the lymphoid tissue received very little radiation dose. The possible mechanisms responsible for lymphocyte depression from these various radiation-dose patterns are discussed

  15. Prediction of midline dose from entrance ad exit dose using OSLD measurements for total irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Heon; Park, Jong Min; Park, So Yeon; Chun, Min Soo; Han, Ji Hye; Cho, Jin Dong; Kim, Jung In [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-06-15

    This study aims to predict the midline dose based on the entrance and exit doses from optically stimulated luminescence detector (OSLD) measurements for total body irradiation (TBI). For TBI treatment, beam data sets were measured for 6 MV and 15 MV beams. To evaluate the tissue lateral effect of various thicknesses, the midline dose and peak dose were measured using a solid water phantom (SWP) and ion chamber. The entrance and exit doses were measured using OSLDs. OSLDs were attached onto the central beam axis at the entrance and exit surfaces of the phantom. The predicted midline dose was evaluated as the sum of the entrance and exit doses by OSLD measurement. The ratio of the entrance dose to the exit dose was evaluated at various thicknesses. The ratio of the peak dose to the midline dose was 1.12 for a 30 cm thick SWP at both energies. When the patient thickness is greater than 30 cm, the 15 MV should be used to ensure dose homogeneity. The ratio of the entrance dose to the exit dose was less than 1.0 for thicknesses of less than 30 cm and 40 cm at 6 MV and 15 MV, respectively. Therefore, the predicted midline dose can be underestimated for thinner body. At 15 MV, the ratios were approximately 1.06 for a thickness of 50 cm. In cases where adult patients are treated with the 15 MV photon beam, it is possible for the predicted midline dose to be overestimated for parts of the body with a thickness of 50 cm or greater. The predicted midline dose and OSLD-measured midline dose depend on the phantom thickness. For in-vivo dosimetry of TBI, the measurement dose should be corrected in order to accurately predict the midline dose.

  16. The Induction of Chromosome Aberrations and Micronuclei in Human Peripheral Blood Lymphocytes at Low Doses of Radiation

    CERN Document Server

    Shmakova, N L; Krasavin, E A; Melnikova, L A; Fadeeva, T A

    2003-01-01

    The chromosome damage induced by the low doses of gamma-irradiation with ^{60}Co and X-rays in peripheral blood lymphocytes has been studied using different cytogenetic assays. Isolated lymphocytes were exposed to 0.01-1.0 Gy, simulated by PHA, and analysed for chromosome aberrations by the metaphase and the anaphase methods, by the micronucleus assay. Despite the quantitative differences in the amount of chromosome damage revealed by different methods, all of them demonstrated complex nonlinear dose dependence of the frequency of aberrant cells and aberrations. At the dose range of 0.01-0.05 Gy the cells showed the highest radiosensitivity; at 0.05-0.5 Gy the dose-independent induction of chromosome damage was revealed. At the doses of 0.5-1.0 Gy the dose-effect curves became linear with the decreased slope compared with the initial one (by a factor of 5 to 10 for different criteria) reflecting a higher radioresistance of the cells. These data confirm the idea that the direct linear extrapolation of high-dos...

  17. Calculation of midplane dose for total body irradiation from entrance and exit dose MOSFET measurements.

    Science.gov (United States)

    Satory, P R

    2012-03-01

    This work is the development of a MOSFET based surface in vivo dosimetry system for total body irradiation patients treated with bilateral extended SSD beams using PMMA missing tissue compensators adjacent to the patient. An empirical formula to calculate midplane dose from MOSFET measured entrance and exit doses has been derived. The dependency of surface dose on the air-gap between the spoiler and the surface was investigated by suspending a spoiler above a water phantom, and taking percentage depth dose measurements (PDD). Exit and entrances doses were measured with MOSFETs in conjunction with midplane doses measured with an ion chamber. The entrance and exit doses were combined using an exponential attenuation formula to give an estimate of midplane dose and were compared to the midplane ion chamber measurement for a range of phantom thicknesses. Having a maximum PDD at the surface simplifies the prediction of midplane dose, which is achieved by ensuring that the air gap between the compensator and the surface is less than 10 cm. The comparison of estimated midplane dose and measured midplane dose showed no dependence on phantom thickness and an average correction factor of 0.88 was found. If the missing tissue compensators are kept within 10 cm of the patient then MOSFET measurements of entrance and exit dose can predict the midplane dose for the patient.

  18. The effect of instrument alignment on peripheral refraction measurements by automated optometer.

    Science.gov (United States)

    Ehsaei, Asieh; Chisholm, Catharine M; Mallen, Edward A H; Pacey, Ian E

    2011-07-01

    Interest in peripheral refraction measurement has grown in recent years in response to the insight it may provide into myopia development. In light of the likely increase in the clinical use of open-field autorefractors for peripheral refraction measurements, the question of instrument alignment and its impact on the accuracy of refraction measurements is raised. The aim of this study was to investigate the accuracy and precision when an open-field device was moved away from alignment with the corneal reflex towards the pupil margins, and to determine the optimum alignment position for peripheral refraction measurements. Autorefractions were performed on the right eyes of 10 healthy participants using the Shin-Nippon NVision-K 5001 autorefractor. At least five measurements were taken with the subject fixating a distance target in the primary position of gaze, and then four peripheral fixation targets located along the horizontal meridian (10° and 20° eccentricities in the nasal and temporal retina). Measurements were taken at seven alignment positions across the pupil for each fixation angle. Refraction was recorded as the spherical and cylindrical power. The central objective refraction achieved under cycloplegia based on the autorefraction result for the whole sample, ranged between -5.62 D and +1.85 D for the value of sphere, with a maximum astigmatism of -1.00 D. Acceptable alignment position range varied with fixation angle but was -1.0 to +1.0 mm in width across the pupil. Peripheral refraction measurements centred on the entrance pupil were as reliable as those centred on the corneal reflex. Our data suggest that for peripheral refraction measurements, there is a range of acceptable positions and operators can be confident of the validity of results obtained if aligned half way between the pupil centre and corneal reflex. The alignment becomes more critical at greater eccentricities. Ophthalmic & Physiological Optics © 2011 The College of Optometrists.

  19. Effect of low-dose gamma radiation on HIV replication in human peripheral blood mononuclear cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y. [British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada); Conway, B. [British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada)]|[British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada). Dept. of Medicine; Montaner, J.S.G. [British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada)]|[British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada). Dept. of Medicine]|[Canadian HIV Trials Network, Vancouver (Canada); O`Shaughnessy, M.V. [British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada)]|[British Columbia Centre for Excellence in HIV/AIDS, British Columbia (Canada). Faculty of Medicine]|[Canadian HIV Trials Network, Vancouver (Canada); Greenstock, C.L. [AECL Research, Chalk River, Ontario (Canada). Radiation Biology and Health Physics Branch

    1996-08-01

    Recent studies have demonstrated that UV light and x-irradiation enhance human immunodeficiency virus (HIV) gene expression. There are few published data on related effects of {gamma}-radiation. This may be of clinical relevance, as radiotherapy has been used extensively for the treatment of acquired immunodeficiency syndrome associated conditions. We have studied the effects of {gamma}-radiation on HIV replication in mono-nuclear cells (MC). These cells were obtained from five seronegative healthy donors, exposed to 0-200 cGy {gamma}-radiation, stimulated with phytohemagglutinin-P (PHA-P) for 24 h, infected with a laboratory strain of HIV (HTLV-IIIB, multiplicity of infection = 0.001), then carried in culture for 14 days. Overall, when considering p24 antigen levels on days 7 and 11 in cultures established from cells exposed to 50 cGy, the maximal levels were significantly higher than those measured in the parallel control cultures taken as a whole (P < 0.05), with viral replication enhanced as much as 1000-fold in one case. No significant cytotoxicity was observed following exposure to doses up to 50 cGy. The mechanism of the observed effect remains unknown but may relate to direct gene activation and/or free radical generation, leading to such activation. To date, there is no evidence that viral stimulation occurs following therapeutic radiation in a clinical setting. (author).

  20. Effect of low-dose gamma radiation on HIV replication in human peripheral blood mononuclear cells

    International Nuclear Information System (INIS)

    Xu, Y.; Conway, B.; O'Shaughnessy, M.V.; Greenstock, C.L.

    1996-01-01

    Recent studies have demonstrated that UV light and x-irradiation enhance human immunodeficiency virus (HIV) gene expression. There are few published data on related effects of γ-radiation. This may be of clinical relevance, as radiotherapy has been used extensively for the treatment of acquired immunodeficiency syndrome associated conditions. We have studied the effects of γ-radiation on HIV replication in mono-nuclear cells (MC). These cells were obtained from five seronegative healthy donors, exposed to 0-200 cGy γ-radiation, stimulated with phytohemagglutinin-P (PHA-P) for 24 h, infected with a laboratory strain of HIV (HTLV-IIIB, multiplicity of infection = 0.001), then carried in culture for 14 days. Overall, when considering p24 antigen levels on days 7 and 11 in cultures established from cells exposed to 50 cGy, the maximal levels were significantly higher than those measured in the parallel control cultures taken as a whole (P < 0.05), with viral replication enhanced as much as 1000-fold in one case. No significant cytotoxicity was observed following exposure to doses up to 50 cGy. The mechanism of the observed effect remains unknown but may relate to direct gene activation and/or free radical generation, leading to such activation. To date, there is no evidence that viral stimulation occurs following therapeutic radiation in a clinical setting. (author)

  1. Dose assessment by quantification of chromosome aberrations and micronuclei in peripheral blood lymphocytes from patients exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Barbosa, Isvania; Pereira-MagnataI, Simey; Amaral, Ademir [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia - GERAR; Sotero, Graca [Fundacao de Hematologia e Hemoterapia, Recife, PE (Brazil); Melo, Homero Cavalcanti [Hospital do Cancer, Recife, PE (Brazil). Centro de Radioterapia de Pernambuco]. E-mail: isvania@uol.com.br

    2005-07-15

    Scoring of unstable chromosome aberrations (dicentrics, rings and fragments) and micronuclei in circulating lymphocytes are the most extensively studied biological means for estimating individual exposure to ionizing radiation (IR), which can be used as complementary methods to physical dosimetry or when the latter cannot be performed. In this work, the quantification of the frequencies of chromosome aberrations and micronuclei were carried out based on cytogenetic analyses of peripheral blood samples from 5 patients with cervical uterine cancer following radiotherapy in order to evaluate the absorbed dose as a result of partial-body exposure to 60Co source. Blood samples were collected from each patient in three phases of the treatment: before irradiation, 24 h after receiving 0.08 Gy and 1.8 Gy, respectively. The results presented in this report emphasize biological dosimetry, employing the quantification of chromosome aberrations and micronuclei in lymphocytes from peripheral blood, as an important methodology of dose assessment for either whole or partial-body exposure to IR.

  2. Chromosomal aberration in peripheral lymphocytes and doses to the active bone marrow in radiotherapy of prostate cancer

    International Nuclear Information System (INIS)

    Gershkevitsh, E.; Trott, K.R.

    2002-01-01

    Purpose: Radiotherapy plays an important role in the management of prostate cancer. Epidemiological data indicate a small but significant risk of radiation-induced leukemia after radiotherapy which might be related to the high mean bone marrow dose associated with radiotherapy of prostate cancer. The purpose of the study was to investigate the relation between the mean bone marrow dose and unstable chromosome aberrations in peripheral blood lymphocytes in patients undergoing conformal radiotherapy for prostate cancer as a possible indicator of risk. Endometrial cancer patients were also included for comparison. Patients and Methods: Nine patients, six with prostate cancer (60-73 years old) and three with endometrial cancer (61-81 years old) treated with radiotherapy were included in the study. The non-bony spaces inside the pelvic bones were outlined on every CT slice using the treatment planning system and mean doses to the bone marrow calculated. Blood samples of the patients were obtained at different times before, during and at the end of treatment. Lymphocytes were cultured in the usual way and metaphases scored for dicentric aberrations. Results: 46 samples from nine patients were obtained. The mean number of metaphases analyzed per sample was 180 with a range from 52 to 435. The mean bone marrow doses for prostate cancer patients ranged from 2.8 to 4.2 Gy and for endometrial cancer patients from 12.8 to 14.8 Gy. The aberration yield increased with the planning target volume and the mean bone marrow dose. Conclusion: The yield of dicentric aberrations for prostate cancer patients correlated closely with the mean bone marrow dose albeit the induction of dicentrics occurred in mature T lymphocytes most of which were probably in transit through the irradiated volumes. Therefore, the observed relationship between dicentrics and mean bone marrow doses are indirect. (orig.) [de

  3. High-dose 8% capsaicin patch in treatment of chemotherapy-induced peripheral neuropathy: single-center experience.

    Science.gov (United States)

    Filipczak-Bryniarska, Iwona; Krzyzewski, Roger M; Kucharz, Jakub; Michalowska-Kaczmarczyk, Anna; Kleja, Justyna; Woron, Jarosław; Strzepek, Katarzyna; Kazior, Lucyna; Wordliczek, Jerzy; Grodzicki, Tomasz; Krzemieniecki, Krzysztof

    2017-08-17

    High-dose capsaicin patch is effective in treatment of neuropathic pain in HIV-associated neuropathy and diabetic neuropathy. There are no studies assessing effectiveness of high-dose capsaicin patch in treatment of chemotherapy-induced peripheral neuropathy. We sought to determine the effectiveness of treatment of pain associated with chemotherapy-induced peripheral neuropathy with high-dose capsaicin patch. Our study group consisted of 18 patients with clinically confirmed oxaliplatin-induced neuropathy. Baseline characteristic including underling disease, received cumulative dose of neurotoxic agent, neuropathic symptoms, prior treatment and initial pain level were recorded. Pain was evaluated with Numeric Rating Scale prior to treatment with high-dose capsaicin and after 1.8 day and after 8 and 12 weeks after introducing treatment. Patients were divided into two groups accordingly to the amount of neurotoxic agent that caused neuropathy (high sensitivity and low sensitivity group). Most frequent symptoms of chemotherapy-induced neuropathy were: pain (88.89%), paresthesis (100%), sock and gloves sensation (100%) and hypoesthesis (100%). Initial pain level was 7.45 ± 1.14. Mean cumulative dose of oxaliplatin after which patients developed symptoms was 648.07 mg/m 2 . Mean pain level after 12 weeks of treatment was 0.20 ± 0.41. When examined according to high and low sensitivity to neurotoxic agent patients with low sensitivity had higher pain reduction, especially after 8 days after introducing treatment (69.55 ± 12.09 vs. 49.40 ± 20.34%; p = 0.02) and after 12 weeks (96.96 ± 5.56 vs. 83.93 ± 18.59%; p = 0.04). High-dose capsaicin patch is an effective treatment for pain associated with chemotherapy-induced neuropathy in patients treated with oxaliplatin. Patients with lower sensitivity to neurotoxic agents have better response to treatment and pain reduction.

  4. measurement of high dose radiation using yellow perspex dosimeter

    International Nuclear Information System (INIS)

    Thamrin, M Thoyib; Sofyan, Hasnel

    1996-01-01

    Measurement of high dose radiation using yellow perspex dosemeter has been carried out. Dose range used was between 0.1 to 3.0 kGy. Measurement of dose rate against Fricke dosemeter as a standard dose meter From the irradiation of Fricke dosemeter with time variation of 3,6,9,12,15 and 18 minute, it was obtained average dose rate of 955.57 Gy/hour, linear equation of dose was Y= 2.333+15.776 X with its correlation factor r = 0.9999. Measurement result using yellow perspex show that correlation between net optical density and radiation dose was not linear with its equation was ODc exp. [Bo + In(dose).Bi] Value of Bo = -0.215 and Bi=0.5020. From the experiment it was suggested that routine dosimeter (yellow perspex) should be calibrated formerly against standard dosemeters

  5. Assay of micronuclei in peripheral blood lymphocytes as a biological indicator of radiation dose

    International Nuclear Information System (INIS)

    Sreedevi, B.; Rao, B.S.

    1994-01-01

    Chromosomal aberration analysis (CA) has regularly been used as a biological dosemeter to evaluate suspected overexposures to ionising radiations. Recently, the micronucleus (MN) assay has been suggested as an alternative method. An attempt has been made to explore the dose response parameters of MN assay in cytokinesis-blocked lymphocytes. Whole blood was irradiated with 60 Co gamma rays or 250 kV p X rays. A dose-dependent increase in micronuclei yield was observed. The dose response could be best described by a linear-quadratic relationship for both gamma rays and X rays. The α and β coefficients were found to be 1.9 x 10 -2 Gy -1 and 5.7 x 10 -2 Gy -2 for gamma rays and 6.3 x 10 -2 Gy -1 and 4.3 x 10 -2 Gy -2 for X rays, respectively. In the low dose region X rays were three times more efficient in inducing micronuclei. The background value derived for 25 samples from healthy individuals ranged from 6-18 micronuclei per 1000 cells, with a mean value of 12 ± 4 x 10 -3 . Biological dose estimates for individuals exposed in the range 0.1-1 Gy made by MN and CA methods yielded similar results for doses ≥ 0.5 Gy. Due to the uncertainties in the background incidence of MN, at present this technique cannot provide reliable estimates at low doses. (author)

  6. Radiation dose measurements in intravenous pyelography

    International Nuclear Information System (INIS)

    Egeblad, M.; Gottlieb, E.

    1975-01-01

    Intravenous pyelography (IVP) and micturition cystourethrography (MCU) are the standard procedures in the radiological examination of children with urinary tract infections and in the control of these children. Gonad protection against radiation is not possible in MCU, but concerning the girls partly possible in IVP. It is of major importance to know the radiation dose in these procedures, especially since the examination is often repeated in the same patients. All IVP were done by means of the usual technique including possible gonad protection. The thermoluminescence dosimeter was placed rectally in the girls and fixed on the scrota in the boys. A total of 50 children was studied. Gonad dose ranged from 140 to 200mR in the girls and from 20 to 70mR in the boys (mean values). The radiation dose in IVP is very low compared to that of MCU, and from this point of view IVP is a dose saving examination in the control of children with urinary tract infections [fr

  7. Endogenous peripheral oxytocin measures can give insight into the dynamics of social relationships: a review

    Directory of Open Access Journals (Sweden)

    Catherine eCrockford

    2014-03-01

    Full Text Available The neuropeptide, oxytocin, receives increasing attention due to its role in stress regulation and promoting affiliative social behavior. Research across mammals points to a complex pattern whereby social context and individual differences moderate the endogenous release of oxytocin as well as moderate the effects that exogenous administration of oxytocin has on social behavior. In addition to measuring central release of oxytocin or exogenous administration of oxytocin on social behavior, for example via inhalation, it is becoming evident that measuring endogenous peripheral oxytocin levels is an additional, informative tool. This is particularly so when oxytocin can be measured from non-invasively collected samples, such as in urine. Although it is still debated as to whether peripheral measures of oxytocin relate to central measures of oxytocin, anatomical and functional evidence indicate a link between the two. We argue that non-invasive measures of peripheral oxytocin hold several research and potential therapeutic advantages. Principally, study subjects can be sampled repeatedly in different social contexts where social history between interaction partners can be taken into account. Several hormones can be measured simultaneously allowing examination of the influence of oxytocin interactions with other hormones on motivational states. Valence of relationships as well as changes in relationship quality over time can be measured through endocrine responses. Also, the approach of identifying natural social contexts that are associated with endogenous oxytocin release offers the potential of behavioral therapy as an addition or alternative to chemical therapy in the field of mental health.

  8. Measurement of gamma radiation doses in nuclear power plant environment

    International Nuclear Information System (INIS)

    Bochvar, I.A.; Keirim-Markus, I.B.; Sergeeva, N.A.

    1976-01-01

    Considered are the problems of measuring gamma radiation dose values and the dose distribution in the nuclear power plant area with the aim of estimating the extent of their effect on the population. Presented are the dosimeters applied, their distribution throughout the controlled area, time of measurement. The distribution of gamma radiation doses over the controlled area and the dose alteration with the increase of the distance from the release source are shown. The results of measurements are investigated. The conclusion is made that operating nuclear power plants do not cause any increase in the gamma radiation dose over the area. Recommendations for clarifying the techniques for using dose-meters and decreasing measurement errors are given [ru

  9. Radiotherapy after high-dose chemotherapy and peripheral blood stem cell support in high-risk breast cancer

    International Nuclear Information System (INIS)

    Hoeller, Ulrike; Heide, Juergen; Kroeger, Nicolaus; Krueger, William; Jaenicke, Fritz; Alberti, Winfried

    2002-01-01

    Purpose: To assess the toxicity and efficacy of radiotherapy with respect to locoregional control after adjuvant high-dose chemotherapy for patients with breast cancer. At first, radiotherapy was withheld because of toxicity concerns, but it was introduced in 1995 because of reported high locoregional relapse rates. Methods and Materials: Between 1992 and 1998, 40 patients with Stage II-III high-risk breast cancer received adjuvant high-dose chemotherapy consisting of thiotepa, mitoxantrone, and cyclophosphamide and peripheral blood stem cell support after four cycles of induction chemotherapy. The chest wall or breast, as well as the supraclavicular nodes, were irradiated with electrons and photons to a median dose of 50.4 Gy in 20 patients. Six additional patients received only supraclavicular irradiation to a median dose of 50.4 Gy. Acute toxicity was scored clinically. Pulmonary function tests were performed in 14 irradiated patients before high-dose chemotherapy and 1.1-4.4 years (median 1.6) after irradiation. The median follow-up time of living patients was 33 vs. 67 months in irradiated (n=26) and nonirradiated (n=14) patients, respectively. Results: G2 and G3 hematologic toxicity occurred in 1 patient each. No clinical pneumonitis or clinical impairment of lung function was observed. After 1-2 years, the lung function tests showed only minor changes in 4 patients. The 3-year locoregional control rate was 92% in the irradiated patients vs. 58% in the nonirradiated patients (p=0.049, actuarial analysis). Conclusion: In this series, adjuvant radiotherapy after adjuvant chemotherapy for breast cancer appeared well tolerated, with improved local regional control and without significant side effects. Longer follow-up and more patient accrual, as well as Phase III trials, are necessary for confirmation

  10. 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

  11. Accuracy and precision of four common peripheral temperature measurement methods in intensive care patients.

    Science.gov (United States)

    Asadian, Simin; Khatony, Alireza; Moradi, Gholamreza; Abdi, Alireza; Rezaei, Mansour

    2016-01-01

    An accurate determination of body temperature in critically ill patients is a fundamental requirement for initiating the proper process of diagnosis, and also therapeutic actions; therefore, the aim of the study was to assess the accuracy and precision of four noninvasive peripheral methods of temperature measurement compared to the central nasopharyngeal measurement. In this observational prospective study, 237 patients were recruited from the intensive care unit of Imam Ali Hospital of Kermanshah. The patients' body temperatures were measured by four peripheral methods; oral, axillary, tympanic, and forehead along with a standard central nasopharyngeal measurement. After data collection, the results were analyzed by paired t-test, kappa coefficient, receiver operating characteristic curve, and using Statistical Package for the Social Sciences, version 19, software. There was a significant meaningful correlation between all the peripheral methods when compared with the central measurement (Ptemperatures of right and left tympanic membranes and the standard central nasopharyngeal measurement (88%). Paired t-test demonstrated an acceptable precision with forehead (P=0.132), left (P=0.18) and right (P=0.318) tympanic membranes, oral (P=1.00), and axillary (P=1.00) methods. Sensitivity and specificity of both the left and right tympanic membranes were more than for other methods. The tympanic and forehead methods had the highest and lowest accuracy for measuring body temperature, respectively. It is recommended to use the tympanic method (right and left) for assessing a patient's body temperature in the intensive care units because of high accuracy and acceptable precision.

  12. Normal tissue tolerance to external beam radiation therapy: Peripheral nerves; Dose de tolerance a l'irradiation des tissus sains: les nerfs peripheriques

    Energy Technology Data Exchange (ETDEWEB)

    Henriques de Figueiredo, B.; Dejean, C.; Sargos, P.; Kantor, G. [Departement de radiotherapie, institut Bergonie, centre regional de lutte contre le cancer, 33 - Bordeaux (France); Huchet, A.; Mamou, N. [Service d' oncologie medicale et de radiotherapie, CHU Saint-Andre, 33 - Bordeaux (France); Loiseau, H. [Service de neurochirurgie, CHU Pellegrin, 33 - Bordeaux (France)

    2010-07-15

    Plexopathies and peripheral neuropathies appear progressively and with several years delay after radiotherapy. These lesions are observed principally after three clinical situations: supraclavicular and axillar irradiations for breast cancer, pelvic irradiations for various pathologies and limb irradiations for soft tissue sarcomas. Peripheral nerves and plexus (brachial and lumbosacral) are described as serial structures and are supposed to receive less than a given maximum dose linked to the occurrence of late injury. Literature data, mostly ancient, define the maximum tolerable dose to a threshold of 60 Gy and highlight also a great influence of fractionation and high fraction doses. For peripheral nerves, most frequent late effects are pain with significant differences of occurrence between 50 and 60 Gy. At last, associated pathologies (diabetes, vascular pathology, neuropathy) and associated treatments have probably to be taken into account as additional factors, which may increase the risk of these late radiation complications. (authors)

  13. Neutron Dose Measurement Using a Cubic Moderator

    International Nuclear Information System (INIS)

    Sheinfeld, M.; Mazor, T.; Cohen, Y.; Kadmon, Y.; Orion, I.

    2014-01-01

    The Bonner Sphere Spectrometer (BSS), introduced In July 1960 by a research group from Rice University, Texas, is a major approach to neutron spectrum estimation. The BSS, also known as multi-sphere spectrometer, consists of a set of a different diameters polyethylene spheres, carrying a small LiI(Eu) scintillator in their center. What makes this spectrometry method such widely used, is its almost isotropic response, covering an extraordinary wide range of energies, from thermal up to even hundreds of MeVs. One of the most interesting and useful consequences of the above study is the 12'' sphere characteristics, as it turned out that the response curve of its energy dependence, have a similar shape compared with the neutron's dose equivalent as a function of energy. This inexplicable and happy circumstance makes it virtually the only monitoring device capable providing realistic neutron dose estimates over such a wide energy range. However, since the detection mechanism is not strictly related to radiation dose, one can expect substantial errors when applied to widely different source conditions. Although the original design of the BSS included a small 4mmx4mmO 6LiI(Eu) scintillator, other thermal neutron detectors has been used over the years: track detectors, activation foils, BF3 filled proportional counters, etc. In this study we chose a Boron loaded scintillator, EJ-254, as the thermal neutron detector. The neutron capture reaction on the boron has a Q value of 2.78 MeV of which 2.34 MeV is shared by the alpha and lithium particles. The high manufacturing costs, the encasement issue, the installation efficiency and the fabrication complexity, led us to the idea of replacing the sphere with a cubic moderator. This article describes the considerations, as well as the Monte-Carlo simulations done in order to examine the applicability of this idea

  14. Computerized assessment of the measurement of individual doses

    International Nuclear Information System (INIS)

    Kiibus, A.

    1981-06-01

    The department for the measurements of individual doses makes regular dose controls by means of film badges for approximately 14000 individuals. The operation is facilitated by a Honeywell Bull Mini 6 Mod 43 computer. The computer language is COBOL applied to registering of in-data such as delivery of badges, film development, calibration, invoices, recording of individual doses and customers. The print-out consists of customers, badge codes, dosimeter lists, development specifications, dose statements, addresses, bills, dose statistics and the register of individuals. As a consequence of charges the activity is financially self-supporting. (G.B.)

  15. Peripheral dose to the testes: the design and clinical use of a practical and effective gonadal shield

    International Nuclear Information System (INIS)

    Fraass, B.A.; Kinsella, T.J.; Harrington, F.S.; Galtstein, E.

    1985-01-01

    A simple and practical gonadal shield has been developed for use near megavoltage radiation fields. The lead shield encloses only the testes, allowing its use with nearly any radiation field that does not include the testes. The dose to the testes with and without the shield has been measured extensively both in phantoms and on patients. The gonadal shield allows a 3 to 10-fold reduction in dose to the testes depending primarily on the distance from the field edge to the gonads. When the shield is used, the gonadal dose is always less than 1% of the patient's prescription dose. Based on our patient studies of testicular injury following conventionally-fractionated irradiation, a dose of less than 50 cGy should preserve normal testicular function

  16. Peripheral dose to the testes: the design and clinical use of a practical and effective gonadal shield.

    Science.gov (United States)

    Fraass, B A; Kinsella, T J; Harrington, F S; Glatstein, E

    1985-03-01

    A simple and practical gonadal shield has been developed for use near megavoltage radiation fields. The lead shield encloses only the testes, allowing its use with nearly any radiation field that does not include the testes. The dose to the testes with and without the shield has been measured extensively both in phantoms and on patients. The gonadal shield allows a 3 to 10-fold reduction in dose to the testes depending primarily on the distance from the field edge to the gonads. When the shield is used, the gonadal dose is always less than 1% of the patient's prescription dose. Based on our patient studies of testicular injury following conventionally-fractionated irradiation, a dose of less than 50 cGy (1% of a typical 5000 cGy treatment regimen) should preserve normal testicular function.

  17. The gonad dose produced by a 60Co irradiation of peripheral, interpleural, and retroperitoneal lymph node groups

    International Nuclear Information System (INIS)

    Hassenstein, E.; Nuesslin, F.; Medizinische Hochschule Hannover

    1976-01-01

    A telecobalt therapy of lymph node groups was simulated on the Alderson phantom and the gonad dose caused by each irradiation field was measured with LiF dosimeters. When the supradiaphragmatic and the para-aortal lymph nodes were irradiated, the ovary dose showed rates up to 20 per thousand of the dose maximum. The irradiation of the same zones brought about a testicle dose of less than 5 per thousand of the dose maximum, and only 1/20 of this rate was achieved when a lead plate of about four cm was used in order to protect the testicles. The results are discussed under the point of view of the genetic risk. (orig.) [de

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  19. The influence of small dose radiation on some molecular and genetic parameters of peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Mel'nov, S.B.; Morozik, P.M.

    2001-01-01

    About 70% of Chernobyl radionuclide fallout was spread on the territory of Belarus. As a result, 2,5 million people now are living in contaminated areas under the pressure of the additional influence of low dose radiation. The aim of the current research is to definite the effects of this factor on some molecular and genetic characteristics of the children - prominent residents of the contaminated areas

  20. Time and dose dependent expression in the proteome of human peripheral blood mononuclear cells with γ-irradiation

    International Nuclear Information System (INIS)

    Nishad, S.; Ghosh, Anu

    2014-01-01

    The aim of present study is to investigate time and dose dependent differential protein expression pattern of human peripheral blood mononuclear cells (PBMCs) after acute gamma irradiation. For this purpose, PBMCs extracted from eight healthy individuals were irradiated using 60 Co gamma rays (0.3 Gy and 1 Gy) and compared with sham irradiated controls. Total proteins were extracted 1 and 4 hour post irradiation and analyzed using 2-D gel electrophoresis. A fold change of 1.5 in spot intensity was considered as 'biological significant'. Protein identification was performed by MALDI-TOF mass spectrometry. The MS/MS spectra were interrogated using Mascot 2.1 for searching against SWISS-PROT database. One-hour post irradiation, 18 proteins showed a significant difference between the sham (0 Gy) and 0.3 Gy irradiated group (6 proteins up-regulated and 12 proteins down-regulated) and 17 proteins between the sham (0 Gy) and 1 Gy irradiated group (9 proteins up-regulated and 8 down-regulated). Four hours after irradiation, 16 proteins were differentially expressed between the sham irradiated and 0.3 Gy treated group (5 proteins up-regulated and 11 proteins downregulated). Relatively high dose of 1 Gy showed modulation of 13 proteins (5 proteins upregulated and 8 proteins down regulated) after 4 hours. There were 15 proteins that were observed both at the early time point of 1-hour and the late time point of 4-hour. Important among these were, proteins involved in cytoskeletal organization like Actin, Plastin-2, Vinculin, PDZ and LIM domain protein, WD repeat containing protein and the chaperone proteins like HSP 90-alpha and Protein disulfide-isomerase A3. Proteins like thiol specific antioxidant peroxiredoxin-6 (indicating increased levels of ROS and oxidative stress) showed dose specific expression while proteins like Ras-related Rap-1b-like protein (involved in cell survival) were observed with both 0.3 Gy and 1 Gy. During the study, human peripheral blood

  1. Studying and measuring the gamma radiation doses in Homs city

    International Nuclear Information System (INIS)

    Sofaan, A. H.

    2001-01-01

    The gamma radiation dose was measured in Homs city by using many portable dosimeters (electronic dosimeter and Geiger-Muller). The measurements were carried out in the indoor and outdoor buildings, for different time period, through one year (1999-2000). High purity germanium detector with low back ground radiation (HpGe) was used to determine radiation element contained in some building and the surrounding soil. The statistical analysis laws were applied to make sure that the measured dose distribution around average value is normal distribution. The measurement indicates that the gamma indoor dose varies from 312μSv/y to 511μSv/y, with the average annual dose of 385μSv/y. However the gamma outdoor dose rate varies from 307μSv/y to 366μSv/y with an average annual dose 385μSv/y. The annual outdoor gamma radiation dose is about %16 lower than the outdoor dose in Homs City. These measurements have indicated that environmental gamma doses in Homs City are relatively low. This is because that most of the soils and rocks in the area are limestone. (author)

  2. Dose-response relationships for chromosome aberrations in peripheral blood lymphocytes after whole- and partial-body irradiations. Pt. 1

    International Nuclear Information System (INIS)

    Liniecki, J.; Bajerska, A.; Wyszynska, K.

    1983-01-01

    Dose-response relationships were established for yield of dicentrics and for a fraction of damaged metaphases in lymphocytes after γ-irradiation of rabbits' whole blood in vitro. These relationships were based on the scoring of cells only in their first post-stimulation division and they served as a reference system for comparison with results of 60 Co γ-irradiation in vivo, either of the whole or of predetermined parts of an animal's body. There was a statistically acceptable agreement between dose-response data established for dicentric yield after whole-body irradiation in vivo and the reference dose-response curve derived from exposure of rabbit's blood in vitro. For partial-body (1/2) irradiations there was a satisfactory agreement between the dose-response curves in vitro for dicentric yield and fraction of metaphases damaged on the one hand and the response in vivo when the latter was related to mean doses to circulating blood. However, there was a drastic disagreement with the dose responses in vitro when measured cytogenetic quantities were plotted versus mean doses to body mass. When the latter were substituted for by comparable doses to circulating blood the in vivo-in vitro agreement was acceptable after irradiation. (orig.)

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

    International Nuclear Information System (INIS)

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

    1980-06-01

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

  4. High dose rate brachytherapy source measurement intercomparison.

    Science.gov (United States)

    Poder, Joel; Smith, Ryan L; Shelton, Nikki; Whitaker, May; Butler, Duncan; Haworth, Annette

    2017-06-01

    This work presents a comparison of air kerma rate (AKR) measurements performed by multiple radiotherapy centres for a single HDR 192 Ir source. Two separate groups (consisting of 15 centres) performed AKR measurements at one of two host centres in Australia. Each group travelled to one of the host centres and measured the AKR of a single 192 Ir source using their own equipment and local protocols. Results were compared to the 192 Ir source calibration certificate provided by the manufacturer by means of a ratio of measured to certified AKR. The comparisons showed remarkably consistent results with the maximum deviation in measurement from the decay-corrected source certificate value being 1.1%. The maximum percentage difference between any two measurements was less than 2%. The comparisons demonstrated the consistency of well-chambers used for 192 Ir AKR measurements in Australia, despite the lack of a local calibration service, and served as a valuable focal point for the exchange of ideas and dosimetry methods.

  5. Measured dose to ovaries and testes from Hodgkin's fields and determination of genetically significant dose

    International Nuclear Information System (INIS)

    Niroomand-Rad, A.; Cumberlin, R.

    1993-01-01

    The purpose of this study was to determine the genetically significant dose from therapeutic radiation exposure with Hodgkin's fields by estimating the doses to ovaries and testes. Phantom measurements were performed to verify estimated doses to ovaries and testes from Hodgkin's fields. Thermoluminescent LiF dosimeters (TLD-100) of 1 x 3 x 3 mm 3 dimensions were embedded in phantoms and exposed to standard mantle and paraaortic fields using Co-60, 4 MV, 6 MV, and 10 MV photon beams. The results show that measured doses to ovaries and testes are about two to five times higher than the corresponding graphically estimated doses for Co-60 and 4 MVX photon beams as depicted in ICRP publication 44. In addition, the measured doses to ovaries and testes are about 30% to 65% lower for 10 MV photon beams than for their corresponding Co-60 photon beams. The genetically significant dose from Hodgkin's treatment (less than 0.01 mSv) adds about 4% to the genetically significant dose contribution to medical procedures and adds less than 1% to the genetically significant dose from all sources. Therefore, the consequence to society is considered to be very small. The consequences for the individual patient are, likewise, small. 28 refs., 3 figs., 5 tabs

  6. A study of the indices of the peripheral blood of women, professionally exposed to low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Bliznakov, V.; Mikhajlov, M.A.; Serafimov, A.; Nikolov, A.

    1979-01-01

    The peripheral blood content in women, which, due to their occupation are exposed to low dose ionizing radiation effect, has been investigated. One hundred and ten women from 20 to 50 years of age and occupation service in a sphere of ionizing radiation from 6 months to 4 years (an average length of 2,5 years) were examined. The unequal external gamma irradiation was the fundamental factor of the radiation effect under conditions of occupational media. The mean annual dose did never exceed the maximum permissible limits. As control, a group of 106 clinically healthy women of the same age and working in the industry but not exposed to radiation effect, was formed. Hemoglobin quantity, erythrocytes and leukocytes number, differential count of leukocytes and thrombocytes number were analyzed. Not any statistically significant differences (p > 0,05) between the mean values of the studied parameters of the control group and this one of women exposed to occupational irradiation were observed. This analysis of the hematological parameters represents the first stage of the already undertaken dynamic examination of the health status of a new and relatively stable contingent of occupationally irradiated persons. (A.B.)

  7. Spectrum of chromosomal aberrations in peripheral lymphocytes of hospital workers occupationally exposed to low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Maffei, Francesca; Angelini, Sabrina; Forti, Giorgio Cantelli; Violante, Francesco S.; Lodi, Vittorio; Mattioli, Stefano; Hrelia, Patrizia

    2004-01-01

    Chromosome aberrations frequency was estimated in peripheral lymphocytes from hospital workers occupationally exposed to low levels of ionizing radiation and controls. Chromosome aberrations yield was analyzed by considering the effects of dose equivalent of ionizing radiation over time, and of confounding factors, such as age, gender and smoking status. Frequencies of aberrant cells and chromosome breaks were higher in exposed workers than in controls (P=0.007, and P=0.001, respectively). Seven dicentric aberrations were detected in the exposed group and only three in controls, but the mean frequencies were not significantly different. The dose equivalent to whole body of ionizing radiation (Hwb) did appear to influence the spectrum of chromosomal aberrations when the exposed workers were subdivided by a cut off at 50 mSv. The frequencies of chromosome breaks in both subgroups of workers were significantly higher than in controls (≤50 mSv, P=0.041; >50 mSv, P=0.018). On the other hand, the frequency of chromatid breaks observed in workers with Hwb >50 mSv was significantly higher than in controls (P=0.015) or workers with Hwb ≤50 mSv (P=0.046). Regarding the influence of confounding factors on genetic damage, smoking status and female gender seem to influence the increase in chromosome aberration frequencies in the study population. Overall, these results suggested that chromosome breaks might provide a good marker for assessing genetic damage in populations exposed to low levels of ionizing radiation

  8. Some cosmic radiation dose measurements aboard flights connecting Zagreb Airport

    International Nuclear Information System (INIS)

    Vukovic, B.; Radolic, V.; Lisjak, I.; Vekic, B.; Poje, M.; Planinic, J.

    2008-01-01

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A320 and ATR40 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or 10 B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb-Paris-Buenos Aires and reversely, when one measured non-neutron cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 μSv/h and the TLD dosimeter registered the dose equivalent of 75 μSv or the average dose rate of 2.7 μSv/h; the neutron dosimeter gave the dose rate of 2.4 μSv/h. In the same month, February 2005, a traveling to Japan (24-h-flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 μSv/h; the neutron dosimeter gave the dose rate of 2.5 μSv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude that the neutron component carried about 50% of the total dose, that was near other known data

  9. Some cosmic radiation dose measurements aboard flights connecting Zagreb Airport

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B.; Radolic, V. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Lisjak, I. [Croatia Airlines, Zagreb (Croatia); Vekic, B. [Rudjer Boskovic Institute, Zagreb (Croatia); Poje, M. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Planinic, J. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia)], E-mail: planinic@ffos.hr

    2008-02-15

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A320 and ATR40 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or {sup 10}B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb-Paris-Buenos Aires and reversely, when one measured non-neutron cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 {mu}Sv/h and the TLD dosimeter registered the dose equivalent of 75 {mu}Sv or the average dose rate of 2.7 {mu}Sv/h; the neutron dosimeter gave the dose rate of 2.4 {mu}Sv/h. In the same month, February 2005, a traveling to Japan (24-h-flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 {mu}Sv/h; the neutron dosimeter gave the dose rate of 2.5 {mu}Sv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude that the neutron component carried about 50% of the total dose, that was near other known data.

  10. Evaluation of usability of the shielding effect for thyroid shield for peripheral dose during whole brain radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Myung Sic; Park, Ju Kyeong; Lee, Seung Hun; Kim, Yang Su; Lee, Sun Young; Cha, Seok Yong [Dept. of Radiation Oncology, Chonbuk National University Hospital, Jeonju (Korea, Republic of)

    2014-12-15

    To reduce the radiation dose to the thyroid that is affected to scattered radiation, the shield was used. And we evaluated the shielding effect for the thyroid during whole brain radiation therapy. To measure the dose of the thyroid, 300cGy were delivered to the phantom using a linear accelerator(Clinac iX VARIAN, USA.)in the way of the 6MV X-ray in bilateral. To measure the entrance surface dose of the thyroid, five glass dosimeters were placed in the 10th slice's surface of the phantom with a 1.5 cm interval. The average values were calculated by measured values in five times each, using bismuth shield, 0.5 mmPb shield, self-made 1.0 mmPb shield and unshield. In the same location, to measure the depth dose of the thyroid, five glass dosimeters were placed in the 10th slice by 2.5 cm depth of the phantom with a 1.5 cm interval. The average values were calculated by measured values in five times each, using bismuth shield, 0.5 mmPb shield, self-made 1.0 mmPb shield and unshield. Entrance surface dose of the thyroid were respectively 44.89 mGy at the unshield, 36.03 mGy at the bismuth shield, 31.03 mGy at the 0.5 mmPb shield and 23.21 mGy at a self-made 1.0 mmPb shield. In addition, the depth dose of the thyroid were respectively 36.10 mGy at the unshield, 34.52 mGy at the bismuth shield, 32.28 mGy at the 0.5 mmPb shield and 25.50 mGy at a self-made 1.0 mmPb shield. The thyroid was affected by the secondary scattering dose and leakage dose outside of the radiation field during whole brain radiation therapy. When using a shield in the thyroid, the depth dose of thyroid showed 11-30% reduction effect and the surface dose of thyroid showed 20-48% reduction effect. Therefore, by using the thyroid shield, it is considered to effectively protect the thyroid and can perform the treatment.

  11. Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

    International Nuclear Information System (INIS)

    Braby, L. A.; Reece, W. D.; Hsu, W. H.

    2003-01-01

    Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation experiments. We have also developed 4.3 mm diameter ion chambers with both tissue equivalent and carbon walls for the purpose of measuring dose mean lineal energy due to all radiations and due to all radiations except neutrons, respectively. By adjusting the gas pressure in the ion chamber, it can be made to simulate tissue volumes from a few nanometers to a few millimeters in diameter. The charge is integrated for 0.1 seconds, and the resulting pulse height is recorded by a multi channel analyzer. The system has been used in a variety of photon and neutron radiation fields, and measured values of dose and dose mean lineal energy are consistent with values extrapolated from measurements made by other techniques at much lower dose rates. It is expected that this technique will prove to be much more reliable than extrapolations from measurements made at low dose rates because these low dose rate exposures generally do not accurately reproduce the attenuation and

  12. 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)

  13. The minimum measurable dose of the sensitive Harshaw TLDs

    International Nuclear Information System (INIS)

    Ben-Shachar, B.; German, U.; Naim, E.

    1991-01-01

    The TL-dose response was measured for the sensitive Harshaw manufactured phosphors (CaF 2 :Dy and CaF 2 :Tm), taking chips from the same batch and from different batches. The relative standard deviations were fitted to a semiempirical expression, from which the minimum measurable doses were derived and compared to the minimum measurable dose calculated by taking 3 times the standard deviation of unirradiated chips. The contribution of the individual calibration of each TLD chip was checked, as well

  14. Measurement of annual dose on porcelain using surface TLD method

    International Nuclear Information System (INIS)

    Xia Junding; Wang Weida; Leung, P.L.

    2001-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of measurement of annual dose using ultrathin (CaSO 4 :Tm) dosage layer on porcelain was studied. The TLD was placed on the part of porcelain without glaze. A comparison of measurement of annual dose for surface TLD, inside TLD and alpha counting on porcelain was made. The results show that this technique is suitable for measuring annual dose and improving accuracy of TL authentication test for both porcelain and pottery

  15. Thermoluminescent dosimeters for low dose X-ray measurements

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  16. The Predictive Value of Inflammation-Related Peripheral Blood Measurements in Cancer Staging and Prognosis

    Directory of Open Access Journals (Sweden)

    Joanna L. Sylman

    2018-03-01

    Full Text Available In this review, we discuss the interaction between cancer and markers of inflammation (such as levels of inflammatory cells and proteins in the circulation, and the potential benefits of routinely monitoring these markers in peripheral blood measurement assays. Next, we discuss the prognostic value and limitations of using inflammatory markers such as neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios and C-reactive protein measurements. Furthermore, the review discusses the benefits of combining multiple types of measurements and longitudinal tracking to improve staging and prognosis prediction of patients with cancer, and the ability of novel in silico frameworks to leverage this high-dimensional data.

  17. Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

    CERN Document Server

    Braby, L A; Reece, W D

    2003-01-01

    Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation exp...

  18. Phantoms for IMRT dose distribution measurement and treatment verification

    International Nuclear Information System (INIS)

    Low, Daniel A.; Gerber, Russell L.; Mutic, Sasa; Purdy, James A.

    1998-01-01

    Background: The verification of intensity-modulated radiation therapy (IMRT) patient treatment dose distributions is currently based on custom-built or modified dose measurement phantoms. The only commercially available IMRT treatment planning and delivery system (Peacock, NOMOS Corp.) is supplied with a film phantom that allows accurate spatial localization of the dose distribution using radiographic film. However, measurements using other dosimeters are necessary for the thorough verification of IMRT. Methods: We have developed a phantom to enable dose measurements using a cylindrical ionization chamber and the localization of prescription isodose curves using a matrix of thermoluminescent dosimetry (TLD) chips. The external phantom cross-section is identical to that of the commercial phantom, to allow direct comparisons of measurements. A supplementary phantom has been fabricated to verify the IMRT dose distributions for pelvis treatments. Results: To date, this phantom has been used for the verification of IMRT dose distributions for head and neck and prostate cancer treatments. Designs are also presented for a phantom insert to be used with polymerizing gels (e.g., BANG-2) to obtain volumetric dose distribution measurements. Conclusion: The phantoms have proven useful in the quantitative evaluation of IMRT treatments

  19. Accuracy and precision of four common peripheral temperature measurement methods in intensive care patients

    Directory of Open Access Journals (Sweden)

    Asadian S

    2016-09-01

    Full Text Available Simin Asadian,1 Alireza Khatony,1 Gholamreza Moradi,2 Alireza Abdi,1 Mansour Rezaei,3 1Nursing and Midwifery School, Kermanshah University of Medical Sciences, 2Department of Anesthesiology, 3Biostatistics & Epidemiology Department, Kermanshah University of Medical Sciences, Kermanshah, Iran Introduction: An accurate determination of body temperature in critically ill patients is a fundamental requirement for initiating the proper process of diagnosis, and also therapeutic actions; therefore, the aim of the study was to assess the accuracy and precision of four noninvasive peripheral methods of temperature measurement compared to the central nasopharyngeal measurement. Methods: In this observational prospective study, 237 patients were recruited from the intensive care unit of Imam Ali Hospital of Kermanshah. The patients’ body temperatures were measured by four peripheral methods; oral, axillary, tympanic, and forehead along with a standard central nasopharyngeal measurement. After data collection, the results were analyzed by paired t-test, kappa coefficient, receiver operating characteristic curve, and using Statistical Package for the Social Sciences, version 19, software. Results: There was a significant meaningful correlation between all the peripheral methods when compared with the central measurement (P<0.001. Kappa coefficients showed good agreement between the temperatures of right and left tympanic membranes and the standard central nasopharyngeal measurement (88%. Paired t-test demonstrated an acceptable precision with forehead (P=0.132, left (P=0.18 and right (P=0.318 tympanic membranes, oral (P=1.00, and axillary (P=1.00 methods. Sensitivity and specificity of both the left and right tympanic membranes were more than for other methods. Conclusion: The tympanic and forehead methods had the highest and lowest accuracy for measuring body temperature, respectively. It is recommended to use the tympanic method (right and left for

  20. Student's music exposure: Full-day personal dose measurements.

    Science.gov (United States)

    Washnik, Nilesh Jeevandas; Phillips, Susan L; Teglas, Sandra

    2016-01-01

    Previous studies have shown that collegiate level music students are exposed to potentially hazardous sound levels. Compared to professional musicians, collegiate level music students typically do not perform as frequently, but they are exposed to intense sounds during practice and rehearsal sessions. The purpose of the study was to determine the full-day exposure dose including individual practice and ensemble rehearsals for collegiate student musicians. Sixty-seven college students of classical music were recruited representing 17 primary instruments. Of these students, 57 completed 2 days of noise dose measurements using Cirrus doseBadge programed according to the National Institute for Occupational Safety and Health criterion. Sound exposure was measured for 2 days from morning to evening, ranging from 7 to 9 h. Twenty-eight out of 57 (49%) student musicians exceeded a 100% daily noise dose on at least 1 day of the two measurement days. Eleven student musicians (19%) exceeded 100% daily noise dose on both days. Fourteen students exceeded 100% dose during large ensemble rehearsals and eight students exceeded 100% dose during individual practice sessions. Approximately, half of the student musicians exceeded 100% noise dose on a typical college schedule. This finding indicates that a large proportion of collegiate student musicians are at risk of developing noise-induced hearing loss due to hazardous sound levels. Considering the current finding, there is a need to conduct hearing conservation programs in all music schools, and to educate student musicians about the use and importance of hearing protection devices for their hearing.

  1. Real-time personal dose measurement and management system

    International Nuclear Information System (INIS)

    Zhang Zhiyong; Cheng Chang; Liu Zhengshan; Yang Huating; Deng Changming; Zhang Xiu; Guo Zhanjie

    2001-01-01

    The composition and design of a real-time personal dose measurement and management system are described. Accordingly, some pertinent hardware circuits and software codes including their operation modes are presented

  2. 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)

  3. Measurement of the equivalent dose in quartz using a regenerative-dose single-aliquot protocol

    International Nuclear Information System (INIS)

    Murray, A.S.; Roberts, R.G.

    1998-01-01

    The principles behind a regenerative-dose single-aliquot protocol are outlined. It is shown for three laboratory-bleached Australian sedimentary quartz samples that the relative change in sensitivity of the optically stimulated luminescence (OSL) during a repeated measurement cycle (consisting of a dose followed by a 10 s preheat at a given temperature and then a 100 s exposure to blue/green light at 125 deg. C) is very similar to that of the 110 deg. C thermoluminescence (TL) peak measured during the preheat cycle. The absolute change in the TL sensitivity with preheat temperature is different for samples containing a natural or a regenerative dose. Furthermore, the absolute change in sensitivity in both the OSL and TL signals is non-linear with regeneration cycle, but the relative change in the OSL signal compared to the following 110 deg. C TL measurement is well approximated by a straight line. Both signals are thought to use the same luminescence centres, and so some common behaviour is not unexpected. A new regenerative-dose protocol is presented which makes use of this linear relationship to correct for sensitivity changes with regeneration cycle, and requires only one aliquot for the estimation of the equivalent dose (D e ). The protocol has been applied to quartz from nine Australian sites. To illustrate the value of the regenerative-dose single-aliquot approach, the apparent values of D e for 13 samples, containing doses of between 0.01 and 100 Gy, have been measured at various preheat temperatures of between 160 and 300 deg. C, using a single aliquot for each D e measurement. Excellent agreement is found between these single-aliquot estimates of D e and those obtained from additive-dose multiple-aliquot and single-aliquot protocols, over the entire dose range

  4. Characteristics of dosemeter types for skin dose measurements in practice

    International Nuclear Information System (INIS)

    Van, D. J.; Bosmans, H.; Marchal, G.; Wambersie, A.

    2005-01-01

    A growing number of papers report deterministic effects in the skin of patients who have undergone interventional radiological procedures. Dose measurements, and especially skin dose measurements, are therefore increasingly important. Methods and acceptable dosemeters are, however, not clearly defined. This paper is the result of a literature overview with regard to assessing the entrance skin dose during radiological examinations by putting a dosemeter on the patient's skin. The relevant intrinsic characteristics, as well as some examples of clinical use of the different detector types, are presented. In this respect, thermoluminescence, scintillation, semiconductor and film dosemeters are discussed and compared with respect to their practical use. (authors)

  5. Rapid Measurement of Neutron Dose Rate for Transport Index

    International Nuclear Information System (INIS)

    Morris, R.L.

    2000-01-01

    A newly available neutron dose equivalent remmeter with improved sensitivity and energy response has been put into service at Rocky Flats Environmental Technology Site (RFETS). This instrument is being used to expedite measurement of the Transport Index and as an ALARA tool to identify locations where slightly elevated neutron dose equivalent rates exist. The meter is capable of measuring dose rates as low as 0.2 μSv per hour (20 μrem per hour). Tests of the angular response and energy response of the instrument are reported. Calculations of the theoretical instrument response made using MCNPtrademark are reported for materials typical of those being shipped

  6. Out-of-field dose measurements in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kaderka, Robert

    2011-07-13

    This thesis describes the results from measurements of the out-of-field dose in radiotherapy. The dose outside the treatment volume has been determined in a water phantom and an anthropomorphic phantom. Measurements were performed with linac photons, passively delivered protons, scanned protons, passively delivered carbon ions as well as scanned carbon ions. It was found that the use of charged particles for radiotherapy reduces the out-of-field dose by up to three orders of magnitude compared to conventional radiotherapy with photons.

  7. Dose measurement method suitable for management of food irradiation

    International Nuclear Information System (INIS)

    Tanaka, Ryuichi

    1990-01-01

    The report describes major features of dose measurement performed for the management of food irradiation processes, and dose measuring methods suitable for this purpose, and outlines some activities for establishing international standards for dose measurement. Traceability studies made recently are also reviewed. Compared with the sterilization of medical materials, food irradiation is different in some major points from a viewpoint of dose measurement: foods can undergo significant changes in bulk density, depending on its properties, during irradiation, and the variation in the uniformity of bulk density can be large within an irradiation unit and among different units. An accurate dosimeter and well-established traceability are essential for food irradiation control, and basically a dosimeter should be high in reproducibility and stable in dose response, and should be easy to readjust for eliminating systematic errors. A new type of dosimeter was developed recently, in which ESR is used to measure the free radicals generated by radiations in crystals of alanine, an amino acid. Standardization of large dose measurement procedures has been carried out by committee E10 set up under ASTM. (N.K.)

  8. Imaging and Measuring Electron Beam Dose Distributions Using Holographic Interferometry

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.

    1975-01-01

    Holographic interferometry was used to image and measure ionizing radiation depth-dose and isodose distributions in transparent liquids. Both broad and narrowly collimated electron beams from accelerators (2–10 MeV) provided short irradiation times of 30 ns to 0.6 s. Holographic images...... and measurements of absorbed dose distributions were achieved in liquids of various densities and thermal properties and in water layers thinner than the electron range and with backings of materials of various densities and atomic numbers. The lowest detectable dose in some liquids was of the order of a few k......Rad. The precision limits of the measurement of dose were found to be ±4%. The procedure was simple and the holographic equipment stable and compact, thus allowing experimentation under routine laboratory conditions and limited space....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-03-01

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

  10. Thermoluminescent dose measurements on board Salyut type orbital stations

    International Nuclear Information System (INIS)

    Akatov, Yu.A.; Arkhangelskij, V.V.; Aleksandrov, A.P.

    1984-06-01

    A small, vibration- and shock-resistant thermoluminescent dosemeter (TLD) system - named PILLE - was developed for orbital stations at the Central Research Institute for Physics, Hungary, to measure the cosmic radiation dose on-board. The first on-board measurements with this system were performed by B. Farkas, the Hungarian astronaut, on the Salyut-6 space station in 1980. The same instrument was used by other crews in the following years. Doses measured at different sites in Salyut-6 are presented. The dose rates varied from 0.7 to 0.11 mGy.day -1 . After the first cosmic measurements, the system was further developed. The minimum detectable dose of the new TLD system is 1 μGy, i.e. less by one order of magnitude than that of the former system. The self-irradiation dose rate of the TLD bulbs is also reduced by more than an order of magnitude to 10 nGy.h -1 , by use of potassium-free glass for the bulb envelope. This new type of PILLE TLD system is currently on-board Salyut-7. The dose rates (0.12-0.23 mGy.day -1 ) measured in 1983 are presented in detail. (author)

  11. Gene expression dose-response changes in microarrays after exposure of human peripheral lung epithelial cells to nickel(II).

    Science.gov (United States)

    Cheng, Robert Y S; Zhao, Ailian; Alvord, W Gregory; Powell, Douglas A; Bare, Robert M; Masuda, Akira; Takahashi, Takashi; Anderson, Lucy M; Kasprzak, Kazimierz S

    2003-08-15

    Occupational exposure to nickel compounds is associated with lung cancer risk; both genotoxic and epigenetic mechanisms have been proposed. For comprehensive examination of the acute effects of nickel(II) acetate on gene expression in cultured human peripheral lung epithelial HPL1D cells, microarray analyses were carried out with cDNA chips (approximately 8000 cDNAs). Cells were exposed for 24 h to nontoxic (50, 100, and 200 microM) or toxic (400, 800, and 1600 microM) nickel(II) concentrations. Cluster analysis was applied to the 868 genes with > or = 2-fold change at any concentration. Two main clusters showed marked up- or down-regulation at the highest, toxic concentrations. The data further subdivided into 10 highly cohesive clusters with high probability, and of these only 2 had the same response trend at low nontoxic as at high concentrations, an observation of clear relevance to the process of high- to low-dose extrapolation in risk assessment. There were 113 genes showing > or = 2-fold change at the three lower nontoxic concentrations, those most relevant to in vivo carcinogenesis. In addition to expected responses of metallothionein, ferritin, and heat-shock proteins, the results revealed for the first time changed expression of some potential cancer-related genes in response to low-dose Ni(II): RhoA, dyskerin, interferon regulatory factor 1, RAD21 homologue, and tumor protein, translationally controlled. Overall, most of the genes impacted by nontoxic concentrations of nickel(II) acetate related to gene transcription, protein synthesis and stability, cytoskeleton, signaling, metabolism, cell membrane, and extracellular matrix.

  12. Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

    International Nuclear Information System (INIS)

    Lubis, L E; Badawy, M K

    2016-01-01

    The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care. (paper)

  13. TLD array for precise dose measurements in stereotactic radiation techniques

    International Nuclear Information System (INIS)

    Ertl, A.; Kitz, K.; Griffitt, W.; Hartl, R.F.E.; Zehetmayer, M.

    1996-01-01

    We developed a new TLD array for precise dose measurement and verification of the spatial dose distribution in small radiation targets. It consists of a hemicylindrical, tissue-equivalent rod made of polystyrene with 17 parallel moulds for an exact positioning of each TLD. The spatial resolution of the TLD array was evaluated using the Leskell spherical phantom. Dose planning was performed with KULA 4.4 under stereotactic conditions on axial CT images. In the Leksell gamma unit the TLD array was irradiated with a maximal dose of 10 Gy with an unplugged 14 mm collimator. The doses delivered to the TLDs were rechecked by diode detector and film dosimetry and compared to the computer-generated dose profile. We found excellent agreement of our measured values, even at the critical penumbra decline. For the 14 mm and 18 mm collimator and for the 11 mm collimator combination we compared the measured and calculated data at full width at half maximum. This TLD array may be useful for phantom or tissue model studies on the spatial dose distribution in confined radiation targets as used in stereotactic radiotherapy. (author)

  14. Construction of dose-effect curves by irradiating peripheral blood mononuclear cells analyzed with the alkaline comet assay

    International Nuclear Information System (INIS)

    Rueda, Lenin; Rosales Jaime; Leon, Kety; Espinoza, Marco

    2015-01-01

    The suitability of the alkaline comet assay to detect levels of DNA damage in human monocytes and lymphocytes under radiation was tested. For this purpose, four dose-effect curves by irradiation of cells isolated from blood samples of 4 young, health and non-smoker donors. A gamma ray source of "6"0Co was used and doses of 0, 2.5, 5 and 7 Gy were delivered to blood cells. The results show good correlation (R2 = 0.973, SD = 0.009) between the radiation dose and DNA damage as measured by the parameter Tail Intensity (percentage of DNA in the tail of the 'comet'). Furthermore, we observe the variability in predicting DNA damage by Gy (7.59, SD = 1.5). Potential use of this technique in the biological dosimetry of ionizing radiations is being evaluated. (author)

  15. Skin Dose Equivalent Measurement from Neutron-Deficient Isotopes

    International Nuclear Information System (INIS)

    Hsu, Hsiao-Hua; Costigan, Steve A.; Romero, Leonard L.; Whicker, Jeffrey J.

    1997-12-01

    Neutron-deficient-isotopes decay via positron emission and/or electron capture often followed by x-ray, gamma-ray, and 0.511 MeV photons from positron annihilation. For cases of significant area and/or personnel contamination with these isotopes, determination of skin dose equivalent (SDE) is required by 10CFR835. For assessment of SDE, we evaluated the MICROSPEC-2(TM) system manufactured by Bubble Technology Industries of Canada which uses three different probes for dose measurement. We used two probes: (1) the X-probe which measures lower energy (4 - 120 keV) photon energy distributions and determines deep dose equivalent, SDE and dose equivalent to eyes, and (2) the B-probe which measures electron (positron) energy distributions, and determines skin dose equivalent. Also, the measured photon and beta spectra can be used to identify radioactive isotopes in the contaminated area. Measurements with several neutron-deficient sources showed that this system provided reasonably accurate SDE rate measurements when compared with calculated benchmark SDE rates with an average percent difference of 40%. Variations were expected because of differences between the assumed geometries used by MlCROSPEC-2 and the calculations when compared to the measurement conditions

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

    International Nuclear Information System (INIS)

    Zeitz, L.; Laughlin, J.S.

    1982-01-01

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

  17. Nonisolated-sensor solid polystyrene absorbed dose measurements

    International Nuclear Information System (INIS)

    Zeitz, L.; Laughlin, J.S.

    1982-01-01

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

  18. [Changes and significance of peripheral blood platelet count in tumor shrinkage induced by a low dose of CTX in T739 mice].

    Science.gov (United States)

    Li, Mo-lin; Jia, Yu-jie; Jiang, Miao-na; Shu, Xiao-hong; Li, Chuan-gang

    2008-06-01

    To establish a mouse model for BTT739 tumor-bearing mice cured by a low dose of cyclophosphamide (CTX). And then to observe the dynamic changes and significance of peripheral blood counts especially blood platelet count during tumor shrinkage induced by a low dose of CTX in T739 mice. Mouse bladder carcinoma tissues were inoculated subcutaneously into T739 mice. Seven days later, different doses of CTX or the same volume of NS were administered intraperitoneally to treat these tumor-bearing T739 mice. Tumor sizes were observed and recorded subsequently to find out the minimal dose of CTX that could cure most of these tumor-bearing mice. Then another 12 tumor-bearing mice were randomly divided into 15 mg/kg CTX treatment group and control group. Blood samples were obtained from orbital venous sinus on different times after CTX treatment. Complete blood counts were performed and the relationship between peripheral blood platelet counts and tumor shrinkage was analyzed. Within 2 weeks after CTX treatment, the speed of tumor shrinkage had a positive relationship with the dose of CTX used; but the survival rate of the tumor-bearing mice had a negative relationship with the dose of CTX used in 2 months after CTX treatment. 15 mg/kg CTX could cure most of the tumor bearing mice, while it had no remarkably inhibitive effects on peripheral blood cells. The perpherial platelet count increased to (1483.4+/-184.4)x10(9)/L in mice 6 h after CTX treatment. There was significant difference compared with that in mice of control group (1086.6+/-81.0)x10(9)/L (P0.05). CTX 15 mg/kg could cure most of bladder tumor-bearing T739 mice. The transient increase of the peripheral platelet count in 6 h after CTX treatment may relate to the antitumor effects of CTX.

  19. Measurement of spatial dose distribution for evaluation operator dose during nero-interventional procedures

    International Nuclear Information System (INIS)

    Han, Su Chul; Hong, Dong Hee

    2016-01-01

    The spatial dose distribution was measured with ionization chamber as preliminary study to evaluate operator dose and to study dose reduction during neuro-interventional procedures. The zone of operators was divided into four area (45, 135, 225, and 315 degree).We supposed that operator exist on the four area and indicated location of critical organs(eyes, breast, gonad). The spatial doses were measured depending on distance( 80, 100, 120, and 140 cm) and location of critical organs. The spatial doses of area of 225 degree were 114.5 mR/h (eyes location), 143.1 mR/h (breast location) and 147 mR/h (gonad location) in 80 cm. When changed location of x-ray generator, spatial dose increased in 18.1±10.5%, averagely. We certified spatial dose in the operator locations, Using the results of this study, It is feasible to protect operator from radiation in neuro-interventional procedures

  20. Measurement of spatial dose distribution for evaluation operator dose during nero-interventional procedures

    Energy Technology Data Exchange (ETDEWEB)

    Han, Su Chul [Division of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Hong, Dong Hee [Dept. of Radiology Science, Far East University, Eumseong (Korea, Republic of)

    2016-09-15

    The spatial dose distribution was measured with ionization chamber as preliminary study to evaluate operator dose and to study dose reduction during neuro-interventional procedures. The zone of operators was divided into four area (45, 135, 225, and 315 degree).We supposed that operator exist on the four area and indicated location of critical organs(eyes, breast, gonad). The spatial doses were measured depending on distance( 80, 100, 120, and 140 cm) and location of critical organs. The spatial doses of area of 225 degree were 114.5 mR/h (eyes location), 143.1 mR/h (breast location) and 147 mR/h (gonad location) in 80 cm. When changed location of x-ray generator, spatial dose increased in 18.1±10.5%, averagely. We certified spatial dose in the operator locations, Using the results of this study, It is feasible to protect operator from radiation in neuro-interventional procedures.

  1. Measurements of the dose due to cosmic rays in aircraft

    International Nuclear Information System (INIS)

    Vukovic, B.; Lisjak, I.; Radolic, V.; Vekic, B.; Planinic, J.

    2006-01-01

    When the primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The cosmic radiation dose aboard A320 and ATR 42 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; radon concentration in the atmosphere was measured with the Alpha Guard radon detector. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed by the flights Zagreb-Paris-Buenos Aires and reversely, when one measured cosmic radiation dose; for 26.7 h of flight, the TLD dosimeter registered the total dose of 75 μSv and the average dose rate was 2.7 μSv/h. In the same month, February 2005, a traveling to Japan (24 h flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 μSv/h

  2. Measurements of the dose due to cosmic rays in aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Lisjak, I. [Croatia Airlines, Zagreb (Croatia); Radolic, V. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Vekic, B. [Rudjer Boskovic Institute, Zagreb (Croatia); Planinic, J. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia)]. E-mail: planinic@ffos.hr

    2006-06-15

    When the primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The cosmic radiation dose aboard A320 and ATR 42 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; radon concentration in the atmosphere was measured with the Alpha Guard radon detector. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed by the flights Zagreb-Paris-Buenos Aires and reversely, when one measured cosmic radiation dose; for 26.7 h of flight, the TLD dosimeter registered the total dose of 75 {mu}Sv and the average dose rate was 2.7 {mu}Sv/h. In the same month, February 2005, a traveling to Japan (24 h flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 {mu}Sv/h.

  3. Remote control and data processing for measurement of radiation dose

    International Nuclear Information System (INIS)

    Zhou Yu; Luo Yisheng; Guo Yong; Ji Gang; Wang Xinggong; Zhang Hong; Zhang Wenzhong

    2004-01-01

    Objective: To protect the workers from the reactor radiation and to improve the accuracy and efficiency of neutron dose measurement. Methods: With the application of remote control technology, a remote control and automatic measurement system for radiation dose measurement(especially for neutron dose) was set up. A Model 6517A electrometer was operated all automatically over RS-232 serial interface using SCPI commands with a computer. Results: The workers could stay far from the reactor and be able to control the portable computer in site though internet or LAN and then to control the 6517A electrometer to implement the dose measurement. After the measurement, the data were transferred to the remote computer near the workers and shared by many experts at the first time through the net. Conclusion: This is the first time that the remote control technology is applied in radiation dose measurement, which has so far been considered can only be performed at a near place. This new system can meet the need of neutron radiobiology researches as well as of the safety and health of the workers. (author)

  4. Measurement of Skin Dose from Using the Treatment Immobilization Devices

    International Nuclear Information System (INIS)

    Je, Jae Yong; Park, Chul Woo; Noh, Kyung Suk

    2009-01-01

    The research was about the relation between the dorsal side dose measured by using the phantom body (Alderson Rando Phantom) and factors like contacted material of the patients, the size of the field, angle of incidence. Compared with mylar (tennis racket), the dose on 10 x 10 cm 2 field size of cotton was increased by 2% and by 8% in the case of breast board. In the case of 15 x 15 cm 2 field size, the dose was increased by 6% compared with 10 x 10 cm 2 size. The field size of 20 x 20 cm 2 resulted in 10% increase of dose, while 5 x 5 cm 2 produced 13% decrease. Compared with incident angle 0 degree, the cases for the incident angle 5 degrees had 0.4% less dose for breast board, 0.5% for tennis racket, 1.1% for cotton. The cases for the incident angle 10 degrees had 1.5% less dose for breast board, 1.9% for tennis racket, 2.6% for cotton. For the incident angle 15 degrees, breast board, tennis racket, cotton caused decrease of dose by 3.9%, 2.6%, 3.86% respectively. Resultantly carbon material can cause more skin dose in treatment field. By the results of this study, we recommend that one should avoid the contact between the carbon material and skin.

  5. Neutron dose and energy spectra measurements at Savannah River Plant

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Soldat, K.L.; Haggard, D.L.; Faust, L.G.; Tomeraasen, P.L.

    1987-08-01

    Because some workers have a high potential for significant neutron exposure, the Savannah River Plant (SRP) contracted with Pacific Northwest Laboratory (PNL) to verify the accuracy of neutron dosimetry at the plant. Energy spectrum and neutron dose measurements were made at the SRP calibrations laboratory and at several other locations. The energy spectra measurements were made using multisphere or Bonner sphere spectrometers, 3 He spectrometers, and NE-213 liquid scintillator spectrometers. Neutron dose equivalent determinations were made using these instruments and others specifically designed to determine dose equivalent, such as the tissue equivalent proportional counter (TEPC). Survey instruments, such as the Eberline PNR-4, and the thermoluminescent dosimeter (TLD)-albedo and track etch dosimeters (TEDs) were also used. The TEPC, subjectively judged to provide the most accurate estimation of true dose equivalent, was used as the reference for comparison with other devices. 29 refs., 43 figs., 13 tabs

  6. Dose measurement of ion implanted silicon by RBS technique

    International Nuclear Information System (INIS)

    Kamawanna, Teerasak; Intarasiri, Saweat; Prapunsri, Chowunchun; Thongleurm, Chome; Maleepatra, Saenee; Singkarat, Somsorn

    2003-10-01

    Surface modification can be achieved by ion implantation. This study used a 1 mm thick silicon wafer as a target which was implanted with Ar+ at 80 keV. The degree of the modification depends on both the ion energy and the implanted dose. The distribution of argon in the silicon substrate and the absolute implanted dose can be measured by using Rutherford Backscattering Spectrometry (RBS). These investigations utilized a 1.7 MV Tandetron accelerator system at Chiang Mai University. The dose determination by a direct calculation is in agreement with the simulation by the SIMNRA code

  7. Assessment of dose measurement uncertainty using RisoScan

    International Nuclear Information System (INIS)

    Helt-Hansen, Jakob; Miller, Arne

    2006-01-01

    The dose measurement uncertainty of the dosimeter system RisoScan, office scanner and Riso B3 dosimeters has been assessed by comparison with spectrophotometer measurements of the same dosimeters. The reproducibility and the combined uncertainty were found to be approximately 2% and 4%, respectively, at one standard deviation. The subroutine in RisoScan for electron energy measurement is shown to give results that are equivalent to the measurements with a scanning spectrophotometer

  8. Assessment of dose measurement uncertainty using RisøScan

    DEFF Research Database (Denmark)

    Helt-Hansen, J.; Miller, A.

    2006-01-01

    The dose measurement uncertainty of the dosimeter system RisoScan, office scanner and Riso B3 dosimeters has been assessed by comparison with spectrophotometer measurements of the same dosimeters. The reproducibility and the combined uncertainty were found to be approximately 2% and 4%, respectiv......%, respectively, at one standard deviation. The subroutine in RisoScan for electron energy measurement is shown to give results that are equivalent to the measurements with a scanning spectrophotometer. (c) 2006 Elsevier Ltd. All rights reserved....

  9. Verification of eye lens dose in IMRT by MOSFET measurement.

    Science.gov (United States)

    Wang, Xuetao; Li, Guangjun; Zhao, Jianling; Song, Ying; Xiao, Jianghong; Bai, Sen

    2018-04-17

    The eye lens is recognized as one of the most radiosensitive structures in the human body. The widespread use of intensity-modulated radiotherapy (IMRT) complicates dose verification and necessitates high standards of dose computation. The purpose of this work was to assess the computed dose accuracy of eye lens through measurements using a metal-oxide-semiconductor field-effect transistor (MOSFET) dosimetry system. Sixteen clinical IMRT plans of head and neck patients were copied to an anthropomorphic head phantom. Measurements were performed using the MOSFET dosimetry system based on the head phantom. Two MOSFET detectors were imbedded in the eyes of the head phantom as the left and the right lens, covered by approximately 5-mm-thick paraffin wax. The measurement results were compared with the calculated values with a dose grid size of 1 mm. Sixteen IMRT plans were delivered, and 32 measured lens doses were obtained for analysis. The MOSFET dosimetry system can be used to verify the lens dose, and our measurements showed that the treatment planning system used in our clinic can provide adequate dose assessment in eye lenses. The average discrepancy between measurement and calculation was 6.7 ± 3.4%, and the largest discrepancy was 14.3%, which met the acceptability criterion set by the American Association of Physicists in Medicine Task Group 53 for external beam calculation for multileaf collimator-shaped fields in buildup regions. Copyright © 2018 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  10. The antiproton depth–dose curve measured with alanine detectors

    CERN Document Server

    Bassler, Niels; Palmans, Hugo; Holzscheiter, Michael H; Kovacevic, Sandra

    2008-01-01

    n this paper we report on the measurement of the antiproton depth–dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen and Olsen for conversion of calculated dose into response. A good agreement is observed between the measured and calculated relative effectiveness although an underestimation of the measured values beyond the Bragg-peak remains unexplained. The model prediction of response of alanine towards heavy charged particles encourages future use of the alanine detectors for dosimetry of mixed radiation fields.

  11. Direct measurement of annual β dose using TLD on porcelain

    International Nuclear Information System (INIS)

    Leung, P.L.; Stokes, M.J.; Xia Junding; Wang Weida; Zhou Zhixin

    1999-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of direct measurement of annual β dose using ultrathin TLD (CaSO 4 :Tm) on porcelain was studied. Since the TLD was placed into a hole left after sampling for the TL measurement, the method will not cause any new damage to the studied object. The results show that the technique is suitable for measuring annual β dose and improving accuracy of TL authentication test for both porcelain and pottery

  12. Oscillometric blood pressure measurement: a simple method in screening for peripheral arterial disease

    DEFF Research Database (Denmark)

    Mehlsen, Jesper; Wiinberg, Niels; Bruce, Christopher

    2008-01-01

    Blood pressure at the ankle level is a reliable indicator of peripheral arterial disease (PAD) and the ankle brachial index (ABI) is a useful non-invasive screening tool for the early detection of atherosclerosis. In the first part of the study, systolic blood pressures obtained by oscillometry...... of PAD was sufficiently high in subjects over the age of 60 years to warrant screening. The ankle brachial index based on measurements with an oscillometric device was shown reliable in the exclusion of PAD, thereby fulfilling an important criterion for the use in screening....

  13. A composite peripheral blood gene expression measure as a potential diagnostic biomarker in bipolar disorder

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Peijs, L; Vinberg, M

    2015-01-01

    as a diagnostic and state biomarker in bipolar disorder. First, messenger RNA levels of 19 candidate genes were assessed in peripheral blood mononuclear cells of 37 rapid cycling bipolar disorder patients in different affective states (depression, mania and euthymia) during a 6-12-month period and in 40 age...... subjects. In patients with bipolar disorder, upregulation of NDUFV2 was observed in a depressed state compared with a euthymic state. The composite gene expression measure for discrimination between patients and healthy control subjects on the basis of 19 genes generated an area under the receiver...

  14. Measurements and applications of dose indices in radiography

    International Nuclear Information System (INIS)

    Chen, T.R.; Tyan, Y.S.; Yang, J.J.; Shao, C.H.; Lin, J.Y.; Tung, C.J.

    2011-01-01

    Assessments of radiation dose and image quality are required in diagnostic radiography for quality assurance and optimization studies. In work currently being undertaken, dose indices were measured and image quality evaluated for a chest PA procedure. Thermoluminescent dosimeters of the GR-200 type were attached to the entrance and exit surfaces and placed at various depths of the PMMA phantom to measure the entrance surface dose, the exit surface dose, and the organ dose index. The effective dose was estimated from the entrance surface dose using PCXMC software. Two contrast-detail image plates, one with air holes for the low contrast objects and the other with gypsum holes for the high contrast objects, were used to obtain radiographic images. This image plate was placed at different depths from the entrance surface of the phantom to simulate objects at different positions in the body. Each image was evaluated by three independent radiologists to determine image quality. Analyses of radiation dose versus image quality were performed to determine the optimal technical factors such as, filtration and tube potential. It was found that an 11-cm thick PMMA phantom best simulated the patients. The fractional dose backscattered from this phantom was between 22% and 27% for kVp’s between 66 and 133. Optimization analyses showed that no extra filter was required. For low contrast objects, an optimal choice of tube potential was 120 kVp. For high contrast objects, a kVp as low as 77 kVp could be used, depending on the image quality requirement.

  15. Assessment of peripheral skeletal muscle microperfusion in a porcine model of peripheral arterial stenosis by steady-state contrast-enhanced ultrasound and Doppler flow measurement.

    Science.gov (United States)

    Naehle, Claas P; Steinberg, Verena A; Schild, Hans; Mommertz, Gottfried

    2015-05-01

    Noninvasive measurement of peripheral muscle microperfusion could potentially improve diagnosis, management, and treatment of peripheral arterial disease (PAD) and thus improve patient care. Contrast-enhanced ultrasound (CEUS) as a noninvasive diagnostic tool allows quantification of muscle perfusion. Increasing data on bolus technique CEUS reflecting microperfusion are becoming available, but only limited data on steady-state CEUS for assessment of muscle microperfusion are available. Therefore, the aim of this study was to evaluate steady-state CEUS for assessment of peripheral muscle microperfusion in a PAD animal model. In a porcine animal model, peripheral muscle microperfusion was quantified by steady-state CEUS replenishment kinetics (mean transit time [mTT] and wash-in rate [WiR]) of the biceps femoris muscle during intravenous steady-state infusion of INN-sulfur hexafluoride (SonoVue; Bracco, Geneva, Switzerland). In addition, macroperfusion was quantified at the external femoral artery with a Doppler flow probe. Peripheral muscle microperfusion and Doppler flow measurements were performed bilaterally at rest and under adenosine stress (70 μg/kg body weight) before and after unilateral creation of a moderate external iliac artery stenosis. All measurements could be performed completely in 10 pigs. Compared with baseline measurements, peripheral muscle microperfusion decreased significantly during adenosine stress (rest vs adenosine stress: mTT, 7.8 ± 3.3 vs 21.2 ± 17.8 s, P = .0006; WiR, 58.4 ± 38.1 vs 25.3 ± 15.6 arbitrary units [a.u.]/s, P flow, 122.3 ± 31.4 vs 83.6 ± 28.1 mL/min, P = .0067) and after stenosis creation (no stenosis vs stenosis: mTT, 8.1 ± 3.1 vs 29.2 ± 18.0 s, P = .0469; WiR, 53.0 ± 22.7 vs 13.6 ± 8.4 a.u./s, P = .0156; Doppler flow, 124.2 ± 41.8 vs 65.9 ± 40.0 mL/min, P = .0313). After stenosis creation, adenosine stress led to a further significant decrease of peripheral muscle microperfusion but had no effect on

  16. Effects of low-dose IV ketamine on peripheral and central pain from major limb injuries sustained in combat.

    Science.gov (United States)

    Polomano, Rosemary C; Buckenmaier, Chester C; Kwon, Kyung H; Hanlon, Alexandra L; Rupprecht, Christine; Goldberg, Cynthia; Gallagher, Rollin M

    2013-07-01

    Examine response patterns to low-dose intravenous (IV) ketamine continuous infusions on multiple pain outcomes, and demonstrate effectiveness, safety, and tolerability of ketamine administration on general wards. Retrospective case series of consecutive patients given low-dose IV ketamine continuous infusions. Walter Reed Army Medical Center, Washington, DC. Nineteen eligible inpatients with neuropathic pain from major limb injuries sustained in combat with inadequate pain control from multimodal analgesia. A 3-day IV infusion of ketamine at doses ≤ 120 μg/kg/h. Daily present (PPI), average (API), and worst (WPI) pain intensity (0-10), global pain relief (GPR) (1 "no relief" to 5 "complete relief"), daily assessments of adverse events, and daily opioid requirements measured during therapy. A significant reduction in PPI (P pain (PLP) (N = 10; P = 0.0436) were observed. Mean percent increase in overall GPR was better for those reporting GPR scores ≤ 3 (N = 13) in the first 24 hours of therapy (P = 0.0153). While not significant, mean opioid requirement (IV morphine equivalents) decreased from 129.9 mgs ± 137.3 on day 1 to 112.14 ± 86.3 24 hours after therapy. Low-dose ketamine infusions for complex combat injury pain were safe and effective, and demonstrated response patterns over time and by baseline pain score stratification and presence or absence of PLP. Wiley Periodicals, Inc.

  17. Anxiety and cerebral blood flow during behavioral challenge. Dissociation of central from peripheral and subjective measures

    International Nuclear Information System (INIS)

    Zohar, J.; Insel, T.R.; Berman, K.F.; Foa, E.B.; Hill, J.L.; Weinberger, D.R.

    1989-01-01

    To investigate the relationship between anxiety and regional cerebral blood flow, we administered behavioral challenges to 10 patients with obsessive-compulsive disorder while measuring regional cerebral blood flow with the xenon 133 inhalation technique. Each patient was studied under three conditions: relaxation, imaginal flooding, and in vivo (actual) exposure to the phobic stimulus. Subjective anxiety, obsessive-compulsive ratings, and autonomic measures (heart rate, blood pressure) increased significantly, but respiratory rate and PCO 2 did not change across the three conditions. Regional cerebral blood flow increased slightly (in the temporal region) during imaginal flooding, but decreased markedly in several cortical regions during in vivo exposure, when anxiety was highest by subjective and peripheral autonomic measures. These results demonstrate that intense anxiety can be associated with decreased rather than increased cortical perfusion and that ostensibly related states of anxiety (eg, anticipatory and obsessional anxiety) may be associated with opposite effects on regional cerebral blood flow

  18. Breast internal dose measurements in a physical thoracic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Silva, S.D.; Oliveira, M.A.; Castro, A.L.S.; Dias, H.G.; Nogueira, L.B.; Campos, T.P.R., E-mail: sadonatosilva@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Hospital das Clinicas de Uberlandia, MG (Brazil). Departamento de Oncologia; Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Anatomia e Departamento de Imagem

    2017-10-01

    Radiotherapy is a cancer treatment intended to deposit the entire prescribed dose homogeneously into a target volume in order to eliminate the tumor and to spare the surrounding healthy tissues. This paper aimed to provide a dosimetric comparison between the treatment planning system (TPS) ECLIPSE from Varian Medical Systems and the internal dosimetric measurements in a breast phantom. The methodology consisted in performing a 3D conformal radiotherapy planning with two tangential opposite parallel fields applied to the synthetic breast in a thoracic phantom. The irradiation was reproduced in the Varian Linear accelerator, model SL - 20 Precise, 6 MV energy. EBT2 Radiochromic films, placed into the glandular equivalent tissue of the breast, were used to measure the spatial dose distribution. The absorbed dose was compared to those values predicted by the treatment planning system; besides, the dosimetric uncertainties were analyzed. The modal absorbed dose was in agreement with the prescribed value of 180 cGy, although few high dose points between 180 and 220 cGy were detected. The findings suggested a non-uniform dose distribution in the glandular tissue of the synthetic breast, similar to those found in the TPS, associated with the irregular anatomic breast shape and presence of inhomogeneities next to the thoracic wall generated by the low lung density. (author)

  19. Biophysical dose measurement using electron paramagnetic resonance in rodent teeth

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Rink, W.J.; Boreham, D.R.

    2003-01-01

    Electron paramagnetic resonance (EPR) dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. However, there are situations that do not involve a human victim (e.g. tests for suspected environmental overexposures, measurements of doses to experimental animals in radiation biology research, or chronology of archaeological deposits). For such cases we have developed an EPR dosimetry technique making use of enamel of teeth extracted from mice. Tooth enamel from both previously irradiated and unirradiated mice was extracted and cleaned by processing in supersaturated KOH aqueous solution. Teeth from mice with no previous irradiation history exhibited a linear EPR response to the dose in the range from 0.8 to 5.5 Gy. The EPR dose reconstruction for a preliminarily irradiated batch resulted in the radiation dose of (1.4±0.2) Gy, which was in a good agreement with the estimated exposure of the teeth. The sensitivity of the EPR response of mouse enamel to gamma radiation was found to be half of that of human tooth enamel. The dosimetric EPR signal of mouse enamel is stable up at least to 42 days after exposure to radiation. Dose reconstruction was only possible with the enamel extracted from molars and premolars and could not be performed with incisors. Electron micrographs showed structural variations in the incisor enamel, possibly explaining the large interfering signal in the non-molar teeth

  20. Indoor gamma dose measurements in Gudalore (India) using TLD

    International Nuclear Information System (INIS)

    Sivakumar, R.; Selvasekarapandian, S.; Mugunthamanikandan, N.; Raghunath, V.M.

    2002-01-01

    Indoor gamma radiation dose rates were measured inside residential buildings in Gudalore using a CaSO 4 : Dy thermoluminescent dosimeter for 1 year . Significant seasonal variations are observed. The highest dose rate is observed during summer and the lowest in winter. The dose rates observed are between 77.9 and 229.3 nGy h -1 and may be attributed to the type of building materials used in the dwellings monitored. The calculated mean annual effective dose equivalent rates range between 477.6 μSv y -1 , for the inhabitants of mud houses to 1406.3 μSv y -1 , for those living in terrace houses made of cement and brick

  1. Indoor gamma dose measurements in Gudalore (India) using TLD

    Energy Technology Data Exchange (ETDEWEB)

    Sivakumar, R.; Selvasekarapandian, S. E-mail: spandian@bharathi.ernet.in; Mugunthamanikandan, N.; Raghunath, V.M

    2002-06-01

    Indoor gamma radiation dose rates were measured inside residential buildings in Gudalore using a CaSO{sub 4} : Dy thermoluminescent dosimeter for 1 year . Significant seasonal variations are observed. The highest dose rate is observed during summer and the lowest in winter. The dose rates observed are between 77.9 and 229.3 nGy h{sup -1} and may be attributed to the type of building materials used in the dwellings monitored. The calculated mean annual effective dose equivalent rates range between 477.6 {mu}Sv y{sup -1}, for the inhabitants of mud houses to 1406.3 {mu}Sv y{sup -1}, for those living in terrace houses made of cement and brick.

  2. Online Radiation Dose Measurement System for ATLAS experiment

    CERN Document Server

    Mandić, I; The ATLAS collaboration

    2012-01-01

    Particle detectors and readout electronics in the high energy physics experiment ATLAS at the Large Hadron Collider at CERN operate in radiation field containing photons, charged particles and neutrons. The particles in the radiation field originate from proton-proton interactions as well as from interactions of these particles with material in the experimental apparatus. In the innermost parts of ATLAS detector components will be exposed to ionizing doses exceeding 100 kGy. Energetic hadrons will also cause displacement damage in silicon equivalent to fluences of several times 10e14 1 MeV-neutrons per cm2. Such radiation doses can have severe influence on the performance of detectors. It is therefore very important to continuously monitor the accumulated doses to understand the detector performance and to correctly predict the lifetime of radiation sensitive components. Measurements of doses are important also to verify the simulations and represent a crucial input into the models used for predicting future ...

  3. Retrospective Correction of Physiological Noise in DTI Using an Extended Tensor Model and Peripheral Measurements

    Science.gov (United States)

    Mohammadi, Siawoosh; Hutton, Chloe; Nagy, Zoltan; Josephs, Oliver; Weiskopf, Nikolaus

    2013-01-01

    Diffusion tensor imaging is widely used in research and clinical applications, but this modality is highly sensitive to artefacts. We developed an easy-to-implement extension of the original diffusion tensor model to account for physiological noise in diffusion tensor imaging using measures of peripheral physiology (pulse and respiration), the so-called extended tensor model. Within the framework of the extended tensor model two types of regressors, which respectively modeled small (linear) and strong (nonlinear) variations in the diffusion signal, were derived from peripheral measures. We tested the performance of four extended tensor models with different physiological noise regressors on nongated and gated diffusion tensor imaging data, and compared it to an established data-driven robust fitting method. In the brainstem and cerebellum the extended tensor models reduced the noise in the tensor-fit by up to 23% in accordance with previous studies on physiological noise. The extended tensor model addresses both large-amplitude outliers and small-amplitude signal-changes. The framework of the extended tensor model also facilitates further investigation into physiological noise in diffusion tensor imaging. The proposed extended tensor model can be readily combined with other artefact correction methods such as robust fitting and eddy current correction. PMID:22936599

  4. Evaluation of MR angiography and blood flow measurement in abdominal and peripheral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Tabuchi, Kenji [Dokkyo Univ. School of Medicine, Mibu, Tochigi (Japan)

    2000-03-01

    To assess the characteristics of blood flow measurement with MR Angiography (MRA) to evaluate the status of vascular stenoses, two or three dimensional time-of-flight MRA and velocity-encoded cine MR were performed in the 230 segments of 35 patients, with abdominal and peripheral arterial occlusive diseases. In 11 of these 35 patients digital subtraction angiography was additionally underwent, and the stenotic findings was compared with MRA. There were 17 segments in which the velocity could not be measured, because the blood flow exceeded the upper limit of peak-encoded velocity (VENC) which was set at 120 cm/sec. Therefore, it is necessary to set the upper limit of VENC at higher than 120 cm/sec. There were 11 stenotic findings in DSA and 20 stenotic findings in MRA. Pulsatility Index (PI=(max velocity-min. velocity)/average velocity) were used for evaluating the blood flow waveform, and there were significant difference between the 11 stenotic findings of DSA and the others'. In summery, MRA was considered as useful examination to assess the degree of the vascular stenoses in abdominal and peripheral arterial occlusive disease. (author)

  5. Accredited dose measurements for validation of radiation sterilized products

    DEFF Research Database (Denmark)

    Miller, A.

    1993-01-01

    for control of radiation sterilization. The accredited services include: 1. 1. Irradiation of dosimeters and test samples with cobalt-60 gamma rays. 2. 2. Irradiation of dosimeters and test samples with 10 MeV electrons. 3. 3. Issue of and measurement with calibrated dosimeters. 4. 4. Measurement...... of the dosimetric parameters of an irradiation facility. 5. 5. Measurement of absorbed dose distribution in irradiated products. The paper describes these services and the procedures necessary for their execution....

  6. Peripheral airway impairment measured by oscillometry predicts loss of asthma control in children.

    Science.gov (United States)

    Shi, Yixin; Aledia, Anna S; Galant, Stanley P; George, Steven C

    2013-03-01

    We previously showed that impulse oscillometry (IOS) indices of peripheral airway function are associated with asthma control in children. However, little data exist on whether dysfunction in the peripheral airways can predict loss of asthma control. We sought to determine the utility of peripheral airway impairment, as measured by IOS, in predicting loss of asthma control in children. Fifty-four children (age, 7-17 years) with controlled asthma were enrolled in the study. Spirometric and IOS indices of airway function were obtained at baseline and at a follow-up visit 8 to 12 weeks later. Physicians who were blinded to the IOS measurements assessed asthma control (National Asthma Education and Prevention Program guidelines) on both visits and prescribed no medication change between visits. Thirty-eight (70%) patients maintained asthma control between 2 visits (group C-C), and 16 patients had asthma that became uncontrolled on the follow-up visit (group C-UC). There was no difference in baseline spirometric results between the C-C and C-UC groups, except for FEV1/forced vital capacity ratio (86% vs 82%, respectively; P IOS results, including resistance of the respiratory system at 5 Hz (R5; 6.4 vs 4.3 cm H2O · L(-1) · s), frequency dependence of resistance (difference of R5 and resistance of the respiratory system at 20 Hz [R5-20]; 2.0 vs 0.7 cm H2O · L(-1) · s), and reactance area (13.1 vs 4.1 cm H2O · L(-1)), of group C-UC were significantly higher than those of group C-C (P operating characteristic analysis showed baseline R5-20 and reactance area effectively predicted asthma control status at the follow-up visit (area under the curve, 0.91 and 0.90). Children with controlled asthma who have increased peripheral airway IOS indices are at risk of losing asthma control. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

  7. The Antiproton Depth Dose Curve Measured with Alanine Detectors

    DEFF Research Database (Denmark)

    Bassler, Niels; Hansen, Johnny Witterseh; Palmans, Hugo

    2008-01-01

    In this paper we report on the measurement of the antiproton depth dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen et Olsen for conversion of calculated dose...... into response. A good agreement was observed between the measured and calculated relative effectiveness although a slight underestimation of the calculated values in the Bragg peak remains unexplained. The model prediction of response of alanine towards heavy charged particles encourages future use...... of the alanine detectors for dosimetry of mixed radiation fields....

  8. Experimental measurements of spatial dose distributions in radiosurgery treatments

    International Nuclear Information System (INIS)

    Avila-Rodriguez, M. A.; Rodriguez-Villafuerte, M.; Diaz-Perches, R.; Perez-Pastenes, M. A.

    2001-01-01

    The measurement of stereotactic radiosurgery dose distributions requires an integrating, high-resolution dosimeter capable of providing a spatial map of absorbed dose. This paper describes the use of a commercial radiochromic dye film (GafChromic MD-55-2) to measure radiosurgery dose distributions with 6 MV X-rays in a head phantom. The response of the MD-55-2 was evaluated by digitizing and analyzing the films with conventional computer systems. Radiosurgery dose distributions were measured using the radiochromic film in a spherical acrylic phantom of 16 cm diameter undergoing a typical SRS treatment as a patient, and were compared with dose distributions provided by the treatment planning system. The comparison lead to mean radial differences of ±0.6 mm, ±0.9 mm, ±1.3 mm, ±1.9 mm, and ±2.8 mm, for the 80, 60, 50, 40, and 30% isodose curves, respectively. It is concluded that the radiochromic film is a convenient and useful tool for radiosurgery treatment planning validation

  9. Ambient dose measurement in some CT departments in Khartoum State

    International Nuclear Information System (INIS)

    Mohammed, S. A. H.

    2012-09-01

    Computerized Tomography (CT) is now one of the most important radiological examinations world wide.The frequency of CT examinations is increasing rapidly from 2% of all radiological examinations in some countries a decade age to 10-15% now. During the imaging procedure, staff may expose to a significant dose. Therefore, ambient dose measurement is important in the shortage of regular personal monitoring in sudan. This study intended to evaluate the ambient dose at some CT departments (Medical Military hospital, Alamal National Hospital, Elnelin Diagnostic Center and Modern Medical Centre). These departments were equipped with daul, 16 and 64 multi detector CT machines. A survey meter (Radios) was used to measure ambient doses in three locations: Doors, Control Rooms and Adjacent Rooms. The ambient dose equivalent (scatter dose) was measured at various distances from the isocenter of the CT unit at various angles to establish isodose cartography. The mean and range of radiation at control room is 10.00-0.20 and mean (7.05μSv/hr,) reception 1.0-0 (0.40) and doors 4.00-100.00 (73.5) for height 1 meter above the ground. For height 2 meters at control room 0-10.00 (6,75), reception 0-90.00 (30) at door 9.00-90.00 (49.50). This study confirms that low levels of radiation dose are received by staff during CT imaging and these levels are within safe limits as prescribed by the national and international regulations. (Author)

  10. Peripheral neuropathy

    Science.gov (United States)

    ... peripheral; Neuritis - peripheral; Nerve disease; Polyneuropathy; Chronic pain - peripheral neuropathy ... Philadelphia, PA: Elsevier; 2016:chap 107. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  11. Dose area product measurement for diagnostic reference levels and analysis of patient dose in dental radiography

    International Nuclear Information System (INIS)

    Han, S.; Lee, B.; Shin, G.; Choi, J.; Kim, J.; Park, C.; Park, H.; Lee, K.; Kim, Y.

    2008-01-01

    In this study, diagnostic reference levels (DRLs) were suggested and patient doses were analysed through the dose-area product value in dental radiography. In intraoral radiography, at three sites, i.e. molar, premolar and incisor on the maxilla and acquired third quartile values: 55.5, 46 and 36.5 mGy cm 2 , respectively, were measured. In panoramic, cephalo-metric and cone beam computed tomography, the values were 120.3, 146 and 3203 mGy cm 2 (16 x 18 cm), respectively. It has been shown that, in intraoral radiography, the patient dose changes proportionally to the value of mA s, but the change in extra-oral radiography in response to mA s could not be confirmed. The authors could confirm, however, the difference in dose according to the manufacturer in all dental radiography examinations, except for panoramic radiography. Depending on the size of hospital, there were some differences in patient dose in intraoral radiography, but no difference in patient dose in extra-oral radiography. (authors)

  12. Online radiation dose measurement system for ATLAS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mandic, I.; Cindro, V.; Dolenc, I.; Gorisek, A.; Kramberger, G. [Jozef Stefan Institute, Jamova 39, Ljubljana (Slovenia); Mikuz, M. [Jozef Stefan Institute, Jamova 39, Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana (Slovenia); Bronner, J.; Hartet, J. [Physikalisches Institut, Universitat Freiburg, Hermann-Herder-Str. 3, Freiburg (Germany); Franz, S. [CERN, Geneva (Switzerland)

    2009-07-01

    In experiments at Large Hadron Collider, detectors and electronics will be exposed to high fluxes of photons, charged particles and neutrons. Damage caused by the radiation will influence performance of detectors. It will therefore be important to continuously monitor the radiation dose in order to follow the level of degradation of detectors and electronics and to correctly predict future radiation damage. A system for online radiation monitoring using semiconductor radiation sensors at large number of locations has been installed in the ATLAS experiment. Ionizing dose in SiO{sub 2} will be measured with RadFETs, displacement damage in silicon in units of 1-MeV(Si) equivalent neutron fluence with p-i-n diodes. At 14 monitoring locations where highest radiation levels are expected the fluence of thermal neutrons will be measured from current gain degradation in dedicated bipolar transistors. The design of the system and tests of its performance in mixed radiation field is described in this paper. First results from this test campaign confirm that doses can be measured with sufficient sensitivity (mGy for total ionizing dose measurements, 10{sup 9} n/cm{sup 2} for NIEL (non-ionizing energy loss) measurements, 10{sup 12} n/cm{sup 2} for thermal neutrons) and accuracy (about 20%) for usage in the ATLAS detector

  13. Online radiation dose measurement system for ATLAS experiment

    International Nuclear Information System (INIS)

    Mandic, I.; Cindro, V.; Dolenc, I.; Gorisek, A.; Kramberger, G.; Mikuz, M.; Bronner, J.; Hartet, J.; Franz, S.

    2009-01-01

    In experiments at Large Hadron Collider, detectors and electronics will be exposed to high fluxes of photons, charged particles and neutrons. Damage caused by the radiation will influence performance of detectors. It will therefore be important to continuously monitor the radiation dose in order to follow the level of degradation of detectors and electronics and to correctly predict future radiation damage. A system for online radiation monitoring using semiconductor radiation sensors at large number of locations has been installed in the ATLAS experiment. Ionizing dose in SiO 2 will be measured with RadFETs, displacement damage in silicon in units of 1-MeV(Si) equivalent neutron fluence with p-i-n diodes. At 14 monitoring locations where highest radiation levels are expected the fluence of thermal neutrons will be measured from current gain degradation in dedicated bipolar transistors. The design of the system and tests of its performance in mixed radiation field is described in this paper. First results from this test campaign confirm that doses can be measured with sufficient sensitivity (mGy for total ionizing dose measurements, 10 9 n/cm 2 for NIEL (non-ionizing energy loss) measurements, 10 12 n/cm 2 for thermal neutrons) and accuracy (about 20%) for usage in the ATLAS detector

  14. Measurement of patient radiation doses in certain urography procedures

    International Nuclear Information System (INIS)

    Sulieman, A.; Barakat, H.; Zailae, A.; Abuderman, A.; Theodorou, K.

    2015-01-01

    Patients are exposed to significant radiation doses during diagnostic and interventional urological procedures. This study aimed to measure patient entrance surface air kerma (ESAK) and to estimate the effective dose during intravenous urography (IVU), extracorporeal shock-wave lithotripsy (ESWL), and ascending urethrogram (ASU) procedures. ESAK was measured in patients using calibrated thermo luminance dosimeters, GR200A). Effective doses (E) were calculated using the National Radiological Protection Board (NRPB) software. A total of 179 procedures were investigated. 27.9 % of the patients underwent IVU procedures, 27.9 % underwent ESWL procedures and 44.2 % underwent ASU procedures. The mean ESAK was 2.1, 4.18 and 4.9 mGy for IVU, ESWL, and ASU procedures, respectively. Differences in patient ESAK for the same procedure were observed. The mean ESAK values were comparable with those in previous studies. (authors)

  15. Measurements of cosmic-ray doses in commercial airline cabins

    International Nuclear Information System (INIS)

    Okano, M.; Fujitaka, K.; Izumo, K.

    1996-01-01

    Cosmic radiation doses which aircrew and air passengers receive in airplanes have been calling attention in many countries especially in the last decade. In this relation, various types of information had been reported on cosmic radiation intensity. In Japan, the cosmic radiation intensity had been measured in commercial airline cabins as well as chartered flights. While the intensity depends on altitude, geomagnetic latitude (or cutoff rigidity), and temporal variation of the solar activity, their doses are often speculated based on paper records on airflights combined with the intensity-altitude relationship. In this study, however, efforts were made to estimate more realistic integrated doses in airline cabins based on actual on-board measurements which had been conducted several dozens of times in each year (e.g., 45 times in 1994 and 27 times in 1995). (author)

  16. Unit of measurement used and parent medication dosing errors.

    Science.gov (United States)

    Yin, H Shonna; Dreyer, Benard P; Ugboaja, Donna C; Sanchez, Dayana C; Paul, Ian M; Moreira, Hannah A; Rodriguez, Luis; Mendelsohn, Alan L

    2014-08-01

    Adopting the milliliter as the preferred unit of measurement has been suggested as a strategy to improve the clarity of medication instructions; teaspoon and tablespoon units may inadvertently endorse nonstandard kitchen spoon use. We examined the association between unit used and parent medication errors and whether nonstandard instruments mediate this relationship. Cross-sectional analysis of baseline data from a larger study of provider communication and medication errors. English- or Spanish-speaking parents (n = 287) whose children were prescribed liquid medications in 2 emergency departments were enrolled. Medication error defined as: error in knowledge of prescribed dose, error in observed dose measurement (compared to intended or prescribed dose); >20% deviation threshold for error. Multiple logistic regression performed adjusting for parent age, language, country, race/ethnicity, socioeconomic status, education, health literacy (Short Test of Functional Health Literacy in Adults); child age, chronic disease; site. Medication errors were common: 39.4% of parents made an error in measurement of the intended dose, 41.1% made an error in the prescribed dose. Furthermore, 16.7% used a nonstandard instrument. Compared with parents who used milliliter-only, parents who used teaspoon or tablespoon units had twice the odds of making an error with the intended (42.5% vs 27.6%, P = .02; adjusted odds ratio=2.3; 95% confidence interval, 1.2-4.4) and prescribed (45.1% vs 31.4%, P = .04; adjusted odds ratio=1.9; 95% confidence interval, 1.03-3.5) dose; associations greater for parents with low health literacy and non-English speakers. Nonstandard instrument use partially mediated teaspoon and tablespoon-associated measurement errors. Findings support a milliliter-only standard to reduce medication errors. Copyright © 2014 by the American Academy of Pediatrics.

  17. Measurement of radiation dose in paediatric micturating cystourethrography

    International Nuclear Information System (INIS)

    Hassan, N. E. A.

    2013-06-01

    Paediatrics and children have been recognized that they have a higher risk of developing cancer from the radiation than adults. Therefor, increased attention has been directed towards the dose to the patients. Micturating Cystourethrography (MCU) is a commonly use ed fluoroscopic procedure in children and commonly used to detect the vesicoureteric reflux (VUR) and show urethral and bladder and abnormalities. This study aims to measure the pediatric patients undergoing MCU. The study was carried out in two hospitals in Khartoum. The entrance surface dose (ESD) was determined determined by indirect method for 45 children. Furthermore, the mean ESD, sd and range resulting from MCU procedures has been estimated to be 0.7±.5 (0.2-2.5) mGy for the total patient population. The radiation dose to the patients is well within established safety limits, in the light of the current practice. The radiation dose results of this study are appropriate for adoption as the local initial dose reference level (DRL) value for this technique. The data presented in this study showed our doses to be approximately 50% lower than the lower mean values presented in the literature.(Author)

  18. Differences in micronucleus induction in peripheral blood reticulocytes of mice exposed to N-ethyl-N-nitrosourea at light and dark dosing times.

    Science.gov (United States)

    Itoh, Keiichi; Masumori, Shoji; Nakajima, Madoka; Hayashi, Makoto; Sakakibara, Hiroyuki; Shimoi, Kayoko

    2012-01-01

    Mammals, including human beings, have a circadian clock system to regulate behavioral and physiological processes. In this study, we investigated the effect of dosing time on micronucleus induction in the bone marrow by evaluating the frequencies of micronucleated peripheral reticulocytes (MNRETs) in mice exposed to N-ethyl-N-nitrosourea (ENU) to assess any difference in genotoxic sensitivity to chemicals between light and dark periods (inactive phase for rodents and active phase for rodents). Male C3H/He mice were treated intraperitoneally with ENU (12.5 or 25 mg/kg body weight) at zeitgeber time (ZT) 3 in the light period or ZT15 in the dark period, and then the time courses of the frequencies of the MNRETs were determined. The frequencies of the MNRETs induced by ENU increased time-dependently and peaked at 48 hr after treatment for ZT3 and ZT15, and were obviously higher in the ZT15 treatment group than the ZT3 treatment group. The MNRETs were measured at 48 hr after treatment with ENU (25 mg/kg body weight) at various dosing times (ZT0, 3, 6, 12, 15 and 18). The frequencies of the MNRETs in mice treated at ZT0, 15 and 18 were significantly higher than those in mice treated at ZT3, 6 and 12. These results suggest that genotoxic sensitivity to chemicals in mouse bone marrow is different between light and dark periods maybe due to different biological responses (detoxification, cell cycle, DNA repair, etc.) related to circadian rhythms.

  19. Dose-effect of ionizing radiation-induced PIG3 gene expression alteration in human lymphoblastoid AHH-1 cells and human peripheral blood lymphocytes.

    Science.gov (United States)

    Liu, Qing-Jie; Zhang, De-Qin; Zhang, Qing-Zhao; Feng, Jiang-Bin; Lu, Xue; Wang, Xin-Ru; Li, Kun-Peng; Chen, De-Qing; Mu, Xiao-Feng; Li, Shuang; Gao, Ling

    2015-01-01

    To identify new ionizing radiation (IR)-sensitive genes and observe the dose-effect of gene expression alteration (GEA) induced by IR. Microarray was used to screen the differentially expressed genes in human lymphoblastoid cells (AHH-1) using three doses of (60)Co γ-rays (0.5-8 Gy at 1 Gy/min). Given that p53-inducible gene 3 (PIG3) was consistently upregulated, the GEA of PIG3 in AHH-1 cells and human peripheral blood lymphocytes (HPBL) induced by γ-rays (1 Gy/min) was measured at messenger RNA (mRNA) and protein levels. The GEA of PIG3 in AHH-1 cells exposed to neutron radiation (californium-252, 0.073 Gy/min) was also quantified. PIG3 was one of the seven differentially expressed genes found in the microarray analysis. The PIG3 mRNA and protein levels in AHH-1 cells were significantly increased from 1-10 Gy of γ-rays 8-72 h or 8-168 h after exposure, respectively. The enhancement was also observed in AHH-1 cells from 0.4-1.6 Gy of neutrons 48 h post-irradiation. The PIG3 mRNA levels (mRNA copy numbers) in HPBL were significantly increased from 1-8 Gy of γ-rays within 4-24 h post-irradiation, but the highest increase in signal-to-noise responsiveness is approximately two-fold, which was less than that of AHH-1 (approximately 20-fold). IR can upregulate the PIG3 gene expression in AHH-1 and HPBL in the early phase after exposure; however, the IR induced expression levels of PIG3 are greater in AHH-1 than HPBL.

  20. Precedents For Authorization Of Contents Using Dose Rate Measurements

    International Nuclear Information System (INIS)

    Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.

    2012-01-01

    For the transportation of Radioactive Material (RAM) packages, the requirements for the maximum allowed dose rate at the package surface and in its vicinity are given in Title 10 of the Code of Federal Regulations, Section 71.47. The regulations are based on the acceptable dose rates to which the public, workers, and the environment may be exposed. As such, the regulations specify dose rates, rather than quantity of radioactive isotopes and require monitoring to confirm the requirements are met. 10CFR71.47 requires that each package of radioactive materials offered for transportation must be designed and prepared for shipment so that under conditions normally incident to transportation the radiation level does not exceed 2 mSv/h (200 mrem/h) at any point on the external Surface of the package, and the transport index does not exceed 10. Before shipment, the dose rate of the package is determined by measurement, ensuring that it conforms to the regulatory limits, regardless of any analyses. This is the requirement for all certified packagings. This paper discusses the requirements for establishing the dose rates when shipping RAM packages and the precedents for meeting these requirements by measurement.

  1. Dose-area product measurement for patients in diagnostic radiography

    International Nuclear Information System (INIS)

    Alkhawad, Safaa Ibrahim Awad Elkarim

    2001-09-01

    There is a wide spread of the utilization of medical diagnostic x-ray in Sudan upon the last years, in private clinics as well as in public hospitals. The aim of this study was to measure the doses to patients from x-ray in radiography departments in Khartoum State. Use was made of ionization chamber that measures the product of dose times the exposed area of the patient in units of Gy cm 2 . The work was performed in 7 hospitals over 250 patients. 71.2% of the patients were males and 28.8% females. From this work, it appears that the chest radiography represent 42% of the total exposure of human body organs to radiography, there was also a clear variation in doses resulting from this exposure for different x-ray machines. The results of this study were compared with similar from Germany, Finland, New Zealand and Norway; which are recently available studies. The comparison showed those investigation of abdomen, spine and pelvis result in higher radiation doses. No data for limb exposure were obtained from these countries, in Sudan exposure of the limb carry radiation doses compared to the rest of the human body.(Author)

  2. Is the dose equivalent index a quantity to be measured

    International Nuclear Information System (INIS)

    Wagner, S.R.

    1980-01-01

    ICRP introduced the concept of Effective Dose Equivalent H(sub)E and fixed the basic limits of radiation exposure in terms of H(sub)I. As H(sub)E cannot be measured, ICRP stated that with external exposure to penetrating radiation the limitation of the Dose Equivalent Index H(sub)I would afford at least as good a level of protection. However, difficulties arise in measuring H(sub)I and in calibrating instruments in terms of H(sub)I, since the height and location of the dose equivalent maximum in the sphere which is the phantom used in the definition of H(sub)I, depend on the energy and the angular distribution of the incident radiation. That is, H(sub)I is not an additive quantity relative to the partial H(sub)I(sub)i-values of the different energy and angular components. Hence, 1) the distribution of dose equivalent in the sphere must be measured in full for a determination of H(sub)I, and 2) it is not possible to calibrate an instrument which does not exhibit the scattering and absorption properties of the sphere, consistently for arbitrary radiation fields in terms of H(sub)I. Thus the calibration in an unidirectional beam would infer an uncertainty which may amount to a factor of up to 4. This would hardly be tolerable as a base for radiation protection provisions. An alternative is to introduce operational quantities which are additive, e.g. 1) the sum of maxima of the dose equivalent distributions in the sphere produced by different radiation components, and 2) the mean dose equivalent in the sphere. Their relation to H(sub)E for different types of radiation and consequences on secondary limits are discussed. (H.K.)

  3. Routine measurement of dose to the bladder: still an utopy?

    International Nuclear Information System (INIS)

    Schaeken, B.; Goor, C.; Weyngaert, D. van den; Middelheim, A.Z.

    1996-01-01

    Dosimetry with alanine is based on the relative and non destructive measurement of stable free radicals produced by radiation. The flexibility of the method (linear dose response, no energy dependence, no dose rate dependence) as well as in detector design makes this method very suited as in vivo dosimetry system for brachytherapy. Absorbed dose to the detector is measured as the signal intensity of the central line of the electron paramagnetic resonance (EPR) powder spectrum of alanine. The dose at the bladder reference point (ICRU 38) can be measured with no additional inconvenience to the patient using a liquid alanine detector (natural oil with alanine crystals of size less than 200 mm) as follows: the balloon of the Foley catheter is filled with ± 7 cc of liquid detector instead of a radio-opaque fluid. By sedimentation the alanine crystals are collected at the posterior surface of the balloon in the vicinity of the bladder reference point. After the treatment the detector is recuperated from the Foley catheter and read out using a small quartz tube. In vitro measurements revealed 1) a perfect linear dose response in the range between 2 Gy and 5 Gy; 2) highly reproducible measurements: 3% (1s) at 1 Gy, 0.3% (1s) at 50 Gy; 3) a minor quantity of oil is leaking through the balloon wall which we expect is of no harm to the patient; 4) retrieving the irradiated alanine crystals from the Foley catheter reduces the EPR signal with a factor 0.927 ± 0.003 (1s); 5) subsequent mixing followed by centrifuge of the detector fluid will result in an EPR signal stable within ± 1% (1s); 6) the detector fluid shows an excellent EPR stability in a period of months after irradiation. We only recently obtained permission of the ethical committee to use this technique in vivo; the results of at least one patient will be discussed

  4. Effective dose measurement at workplaces within an instrumented anthropomorphic phantom

    International Nuclear Information System (INIS)

    Villagrasa, C.; Darreon, J.; Martin-Burtat, N.; Clairand, I.; Colin, J.; Fontbonne, J. M.

    2011-01-01

    The Laboratory of Ionizing Radiation Dosimetry of the IRSN (France) is developing an instrumented anthropomorphic phantom in order to measure the effective dose for photon fields at workplaces. This anthropomorphic phantom will be equipped with small active detectors located inside at chosen positions. The aim of this paper is to present the development of these new detectors showing the results of the characterisation of the prototype under metrological conditions. New evaluations of the effective dose for standard and non-homogenous irradiation configurations taking into account the real constraints of the project have been done validating the feasibility and utility of the instrument. (authors)

  5. Physical requirements for measurement of radiation dose and their relationship to personnel dose meter design and use

    International Nuclear Information System (INIS)

    Chabot, G.E. Jr.; Jimenez, M.A.; Skrable, K.W.

    1978-01-01

    This paper stems from the concerns of the authors with both the design of current personnel dose meters and the interpretation of dose information from them in light of the actual physical requirements to measure dose. These concerns have been reinforced and extended following a comparative study of the responses of particular TLD and film systems and as the result of a recent national survey on personnel dosimetry conducted by the authors. Among the major points discussed are the systems available for penetrating and shallow dose assessment, dose meter calibration, the measurement and interpretation of skin dose, and the deficiencies of neutron albedo dose meters for routine personnel use. Calibration considerations address the questions of whether or not a phantom should be used and the difference in interpretation of responses with and without a phantom; the relationship between calculated and measured doses; and electronic equilibrium considerations in the measurement of photon doses. Matters of importance in relation to skin dose measurement include techniques in use to interpret skin dose from dose meter response; the appropriateness of evaluation of the surface dose to the live skin layer versus the average dose to the live skin layer and the limitations and requirements on dose meter design with respect to the dose being evaluated; and the significance of dose meter response in relationship to currently used beta calibration standards. Regarding the use of TLD albedo type neutron dose meters currently available, considerations are extended to the strong energy spectral dependence of the dose meter response and the possibility of making significant over or underestimations of neutron dose equivalent, depending on the calibration techniques used and the spectral quality encountered. (author)

  6. KERMA-based radiation dose management system for real-time patient dose measurement

    Science.gov (United States)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  7. Measurement of radiation dose with a PC-based instrument

    International Nuclear Information System (INIS)

    Jangland, L.; Neubeck, R.

    1994-01-01

    The purpose of this study was to investigate in what way the introduction of Digital Subtraction Angiography has influenced absorbed doses to the patient and personnel. Calculation of the energy imparted to the patient, ε, was based on measurements of the dose-area product, tube potential and tube current which were registered with a PC-based instrument. The absorbed doses to the personnel were measured with TLD. The measurements on the personnel were made only at the digital system. The results indicate large variations in ε between different types of angiographic examinations of the same type. The total ε were similar on both systems, although the relative contribution from image acquisition and fluoroscopy were different. At the conventional system fluoroscopy and image acquisition contributed almost equally to the total ε. At the digital system 25% of the total ε was due to fluoroscopy and 75% to image acquisition. The differences were due to longer fluoroscopic times on the conventional system, mainly due to lack of image memory and road mapping, and lower ε/image, due to lower dose settings to the film changer compared to the image intensifier on the digital system. 11 refs., 8 figs., 9 tabs

  8. Dose measurements in space by the Hungarian Pille TLD system

    International Nuclear Information System (INIS)

    Apathy, I.; Deme, S.; Feher, I.; Akatov, Y.A.; Reitz, G.; Arkhanguelski, V.V.

    2002-01-01

    Exposure of crew, equipment, and experiments to the ambient space radiation environment in low Earth orbit poses one of the most significant problems to long-term space habitation. Accurate dose measurement has become increasingly important during the assembly (extravehicular activity (EVA)) and operation of space stations such as on Space Station Mir. Passive integrating detector systems such as thermoluminescent dosemeters (TLDs) are commonly used for dosimetry mapping and personal dosimetry on space vehicles. The well-known advantages of passive detector systems are their independence of power supply, small dimensions, high sensitivity, good stability, wide measuring range, resistance to environmental effects, and relatively low cost. Nevertheless, they have the general disadvantage that for evaluation purposes they need a laboratory or large--in mass and power consumption--terrestrial equipment, and consequently they cannot provide time-resolved dose data during long-term space flights. KFKI Atomic Energy Research Institute (KFKI AEKI) has developed and manufactured a series of thermoluminescent dosemeter systems for measuring cosmic radiation doses in the 10 μGy to 10 Gy range, consisting of a set of bulb dosemeters and a compact, self-contained, TLD reader suitable for on-board evaluation of the dosemeters. By means of such a system, highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle. A detailed description of the system is given and the comprehensive results of these measurements are summarised

  9. 128 slice computed tomography dose profile measurement using thermoluminescent dosimeter

    International Nuclear Information System (INIS)

    Salehhon, N; Hashim, S; Karim, M K A; Ang, W C; Musa, Y; Bahruddin, N A

    2017-01-01

    The increasing use of computed tomography (CT) in clinical practice marks the needs to understand the dose descriptor and dose profile. The purposes of the current study were to determine the CT dose index free-in-air (CTDI air ) in 128 slice CT scanner and to evaluate the single scan dose profile (SSDP). Thermoluminescent dosimeters (TLD-100) were used to measure the dose profile of the scanner. There were three sets of CT protocols where the tube potential (kV) setting was manipulated for each protocol while the rest of parameters were kept constant. These protocols were based from routine CT abdominal examinations for male adult abdomen. It was found that the increase of kV settings made the values of CTDI air increased as well. When the kV setting was changed from 80 kV to 120 kV and from 120 kV to 140 kV, the CTDI air values were increased as much as 147.9% and 53.9% respectively. The highest kV setting (140 kV) led to the highest CTDI air value (13.585 mGy). The p -value of less than 0.05 indicated that the results were statistically different. The SSDP showed that when the kV settings were varied, the peak sharpness and height of Gaussian function profiles were affected. The full width at half maximum (FWHM) of dose profiles for all protocols were coincided with the nominal beam width set for the measurements. The findings of the study revealed much information on the characterization and performance of 128 slice CT scanner. (paper)

  10. Minimizing and measuring lens dose when giving cranial irradiation

    International Nuclear Information System (INIS)

    Woo, S.Y.; Donaldson, S.S.; Heck, R.J.; Nielson, K.L.; Shostak, C.

    1989-01-01

    Three different techniques of administering cranial irradiation were used to determine the dose to the lens as measured in the Rando phantom. The techniques employed were as follows: (1) the central axis of the radiation beam was placed at the thickest portion of the cranium; (2) the central axis of the radiation beam was placed at the lateral orbital rim (bon canthus); (3) the central axis of the radiation beam was placed at the thickest portion of the cranium but with the beam angled 5deg posteriorly away from the eye. Thermal luminescent dosimeters (TLD) were placed in a phantom, at a point determined from a life-sized anatomical section of the plane through the midsection of the eye, to be at the location of the posterior capsule of the lens. In addition, TLDs were placed on the outer surface of the phantom head, directly lateral to the location determined to be where the lens would lie. With equally weighted lateral opposed beams, delivering a midplane dose of 200cGy, the TLDs at the point of the lens measured 21, 9.9 and 10.6% of the midplane doses from the three techniques respectively. TLDs placed directly lateral to the lens on the surface of the phantom head gave an approximation of the lens dose, particularly when techniques 2 and 3 were used. Isodose curve generated by a General Electric treatment planning computer gave lens doses similar to those of the phantom data for each of the three different radiotherapy techniques. Cranial irradiation should be carried out by either technique 2 or technique 3 to minimize radiation dose to the lens. (author). 11 refs.; 2 figs.; 3 tabs

  11. A unique experiment. Measurement of radiation doses at Vinca

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-07-15

    For the first time in the history of the peaceful applications of atomic energy, an experiment was conducted to determine the exact levels of radiation exposure resulting from a reactor incident. The experiment was made at Vinca, Yugoslavia, wherein October 1958 six persons had been subjected to high doses of neutron and gamma radiation during a brief uncontrolled run of a zero-power reactor. One of them died but the other five were successfully treated at the Curie Hospital in Paris. In the case of four of them, the treatment involved the grafting of healthy bone marrow to counteract the effects of radiation on blood-forming tissues. It was recognized that if the effects produced on the irradiated persons could be related to the exact doses of radiation they had received, it would be possible to gain immensely valuable knowledge about the biological consequences of acute and high level radiation exposure on a quantitative basis. It was suggested to the Yugoslav authorities that a dosimetry experiment be conducted at Vinca. The most accurate modern techniques of dosimetry developed at the Oak Ridge National Laboratory were employed during the experiment. Simultaneous measurements of the neutron and gamma doses were made at points where the people had been located. At these points the effects of the radiation on the salt solution in the phantoms were studied. In particular, the energy distribution of the radiation was investigated.It was the ratio between the various components of the radiation that was of special interest in these measurements because this ratio itself would help in determining the exact doses. The dose of one of the components, viz. slow neutrons, had already been determined during the treatment of the patients. If the ratio of the components could be ascertained, the doses of the fast neutrons and gamma rays could also be established because the ratio would not be affected by the power level at which the reactor was operated

  12. Estimating average glandular dose by measuring glandular rate in mammograms

    International Nuclear Information System (INIS)

    Goto, Sachiko; Azuma, Yoshiharu; Sumimoto, Tetsuhiro; Eiho, Shigeru

    2003-01-01

    The glandular rate of the breast was objectively measured in order to calculate individual patient exposure dose (average glandular dose) in mammography. By employing image processing techniques and breast-equivalent phantoms with various glandular rate values, a conversion curve for pixel value to glandular rate can be determined by a neural network. Accordingly, the pixel values in clinical mammograms can be converted to the glandular rate value for each pixel. The individual average glandular dose can therefore be calculated using the individual glandular rates on the basis of the dosimetry method employed for quality control in mammography. In the present study, a data set of 100 craniocaudal mammograms from 50 patients was used to evaluate our method. The average glandular rate and average glandular dose of the data set were 41.2% and 1.79 mGy, respectively. The error in calculating the individual glandular rate can be estimated to be less than ±3%. When the calculation error of the glandular rate is taken into consideration, the error in the individual average glandular dose can be estimated to be 13% or less. We feel that our method for determining the glandular rate from mammograms is useful for minimizing subjectivity in the evaluation of patient breast composition. (author)

  13. Measurement system for depth dose distribution in cancer therapy

    International Nuclear Information System (INIS)

    Nishizawa, Hiroshi; Fujiwara, Hirotsugu; Tsutaka, Yoshikazu; Ikeda, Ikuo

    1999-01-01

    An accurate estimation of an absorbed dose distribution in human tissue is indispensable to efficiently perform radiotherapy in humans. Previously, various methods for such estimation have been developed, however, there is some problem in those methods, it takes too long times (3-4 hours) to determine the absorbed dose distribution through scanning by ionization chamber in water phantom. So, a determination system of depth dose was developed with an aim to determine the absorbed dose of X-ray or electron beam in materials similar to human body. This system was composed of a detector including scintillation fibers which allows emission due to radio-interaction, CCD camera for determination of light distribution of the emission and personal computer for data processing. Though the accuracy of this system was ±2% similar to that of the conventional measuring method, measuring time was reduced to almost 5 min, markedly shorter than that of the conventional water phantom (3-4 hours). The efficacy of works including the adjustment of irradiation system, planning, etc. would be improved by application of this system. (M.N.)

  14. Dose measurements in laboratory of Physics department, University of Khartoum

    International Nuclear Information System (INIS)

    Hamid, Maria Mohammed

    1999-05-01

    Personal monitoring in University of Khartoum is being conducted using thermoluminescent dosimetry. The purpose of the study is to measure the dose of radiation in laboratory of Physics in physics department. TL phosphors LiF: Mg, Ti (card) and LiF Mg, Cu, P (GR-200) and mini-rad dosimeter are used to measure the dose in laboratory. The total dose for students form the laboratory bu using card, GR-200 and mini-rad dosimeter was found to be 2.2μ sv/year. 2.5 μ sv/year and 2.6 μ sv respectively, and for the teacher about 4.0 μ sv/year, 5.8 μ sv/year and 13.6 μ sv/year respectively, and for the dose near junk room about 3.9 μ sv/year, 2.9 μ sv/year and 2.8 μ sv/year by using card, GR-200 and mini-rad dosimeter respectively. There is just a background radiation in the main library and the applied nuclear.(Author)

  15. Experimental evaluation of a MOSFET dosimeter for proton dose measurements

    International Nuclear Information System (INIS)

    Kohno, Ryosuke; Nishio, Teiji; Miyagishi, Tomoko; Hirano, Eriko; Hotta, Kenji; Kawashima, Mitsuhiko; Ogino, Takashi

    2006-01-01

    The metal oxide semiconductor field-effect transistor (MOSFET) dosimeter has been widely studied for use as a dosimeter for patient dose verification. The major advantage of this detector is its size, which acts as a point dosimeter, and also its ease of use. The commercially available TN502RD MOSFET dosimeter manufactured by Thomson and Nielsen has never been used for proton dosimetry. Therefore we used the MOSFET dosimeter for the first time in proton dose measurements. In this study, the MOSFET dosimeter was irradiated with 190 MeV therapeutic proton beams. We experimentally evaluated dose reproducibility, linearity, fading effect, beam intensity dependence and angular dependence for the proton beam. Furthermore, the Bragg curve and spread-out Bragg peak were also measured and the linear-energy transfer (LET) dependence of the MOSFET response was investigated. Many characteristics of the MOSFET response for proton beams were the same as those for photon beams reported in previous papers. However, the angular MOSFET responses at 45, 90, 135, 225, 270 and 315 degrees for proton beams were over-responses of about 15%, and moreover the MOSFET response depended strongly on the LET of the proton beam. This study showed that the angular dependence and LET dependence of the MOSFET response must be considered very carefully for quantitative proton dose evaluations

  16. Measurement of doses to aviator pilots using thermoluminescent dosemeters

    International Nuclear Information System (INIS)

    Azorin N, J.; Cruz C, D.; Rivera M, T.

    2004-01-01

    During the development of their work, the aviator pilots are exposed at high levels of natural radiation of bottom caused mainly by the cosmic radiation of galactic origin and lot. For such reason, the Metropolitan Autonomous University (UAM) and the Union Association of Aviator Pilots (ASPA), subscribed an agreement with the purpose of to measure the doses of ionizing radiation received by the aviator pilots of diverse air companies that man different types of airships and to determine if these doses surpass the one limit of 0.11 mSv/h settled down by the IAEA for the public in general; and if therefore, these workers should be considered as personnel occupationally exposed. In this work the obtained results when measuring the absorbed dose received by Mexican civil aviator pilots during the development of their work, using thermoluminescent dosemeters of LiF:Mg,Cu,P + Ptfe of national production are presented. The obtained results during the years of 2001 and 2002 show that the monthly doses received by the pilots surpass the one it limits established for the public in general, for what they should be considered as personnel occupationally exposed. (Author)

  17. Dermatologic radiotherapy and thyroid cancer. Dose measurements and risk quantification

    International Nuclear Information System (INIS)

    Goldschmidt, H.; Gorson, R.O.; Lassen, M.

    1983-01-01

    Thyroid doses for various dermatologic radiation techniques were measured with thermoluminescent dosimeters and ionization rate meters in an Alderson-Rando anthropomorphic phantom. The effects of changes in radiation quality and of the use or nonuse of treatment cones and thyroid shields were evaluated in detail. The results indicate that the potential risk of radiogenic thyroid cancer is very small when proper radiation protection measures are used. The probability of radiogenic thyroid cancer developing and the potential mortality risk were assessed quantitatively for each measurement. The quantification of radiation risks allows comparisons with risks of other therapeutic modalities and the common hazards of daily life

  18. Low doses of a neonicotinoid insecticide modify pheromone response thresholds of central but not peripheral olfactory neurons in a pest insect.

    Science.gov (United States)

    Rabhi, Kaouther K; Deisig, Nina; Demondion, Elodie; Le Corre, Julie; Robert, Guillaume; Tricoire-Leignel, Hélène; Lucas, Philippe; Gadenne, Christophe; Anton, Sylvia

    2016-02-10

    Insect pest management relies mainly on neurotoxic insecticides, including neonicotinoids, leaving residues in the environment. There is now evidence that low doses of insecticides can have positive effects on pest insects by enhancing various life traits. Because pest insects often rely on sex pheromones for reproduction, and olfactory synaptic transmission is cholinergic, neonicotinoid residues could modify chemical communication. We recently showed that treatments with different sublethal doses of clothianidin could either enhance or decrease behavioural sex pheromone responses in the male moth, Agrotis ipsilon. We investigated now effects of the behaviourally active clothianidin doses on the sensitivity of the peripheral and central olfactory system. We show with extracellular recordings that both tested clothianidin doses do not influence pheromone responses in olfactory receptor neurons. Similarly, in vivo optical imaging does not reveal any changes in glomerular response intensities to the sex pheromone after clothianidin treatments. The sensitivity of intracellularly recorded antennal lobe output neurons, however, is upregulated by a lethal dose 20 times and downregulated by a dose 10 times lower than the lethal dose 0. This correlates with the changes of behavioural responses after clothianidin treatment and suggests the antennal lobe as neural substrate involved in clothianidin-induced behavioural changes. © 2016 The Author(s).

  19. Entrance surface dose measurements in mammography using thermoluminescence technique

    International Nuclear Information System (INIS)

    Rivera, T.; Vega C, H.R.; Manzanares A, E; Azorin, J.; Gonzalez, P.R.

    2007-01-01

    Full text: Of the various techniques that can be used for personnel dosimetry, thermoluminescence dosimetry (TLD) has emerged as a superior technique due to its manifold advantages over other methods of dose estimation. Various phosphors have been therefore investigated regarding their suitability for dosimetry. In this paper, a dosimetry system based on thermally stimulated luminescence (TSL) from zirconium oxide phosphors embedded in polytetrafluorethylene (ZrO 2 +PTFE) was developed for entrance surface doses (ES) measurements in mammography. Small ZrO 2 pellets of 5 mm in diameter and 0.8 mm in thickness were used. The reproducibility of measurements and linearity of ZrO 2 were also studied. The results were compared with those obtained from LiF:Mg,Cu,P usually used for the determination of absorbed dose in mammography. Measurements both per unit air kerma and In vivo were performed using a mammography unit model DMR (General Electric). The results showed that ZrO 2 TLDs can be used for the same X-ray dosimetry applications as LiF:Mg,Cu,P, with each type having the disadvantage of a response dependent on energy, particularly at low energies. These results indicate a considerable potential for use in routine control and In vivo ES measurements in mammography. (Author)

  20. Measurement of computed tomography dose profile with pitch variation using Gafchromic XR-QA2 and thermoluminescence dosimeter (TLD)

    Science.gov (United States)

    Purwaningsih, S.; Lubis, L. E.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    This research was aimed to check the patterns of dose profile on adult and pediatric head scan. We compared measurement result on dose profile along the z- axis rotation at peripheries and center phantom with a variety of pitch, i.e. 0.75, 1, 1.5 for adult and pediatric head protocol, keeping the rest of the scan parameters constant. Measurements were performed on homogeneous, cylindrical PMMA phantom with diameters of 16 and 10 cm using XR-QA2 Gafchromic film and TLD as dosimeters. The measurement result indicated a decrease in the dose about 50% and 47% for adult and pediatric head scan with the increase of pitch. For 0.75 value of pitch adult head scan, dose range for each position were (2.4 - 5.0) cGy, (3.1 - 5.3) cGy, (2.2 - 4.5) cGy, (2.8 - 5.3) cGy, and (3.3 - 5.6) cGy for position of center, 3, 6, 9 and 12 o'clock peripheral phantom position respectively. Dose profile for adult and pediatric head scan protocols has pattern curve with the maximum dose in the middle and tendency of symmetry near the edges, with different the plateau length along z- axis direction in accordance to the measurement position in the phantom.

  1. Comparison of two techniques for natural dose measurements

    International Nuclear Information System (INIS)

    Ekdal, E.; Ege, A.; Goekce, M.; Karali, T.; Derin, Z.

    2006-01-01

    In the study of luminescence dating, age of an archaeological sample is calculated by the ratio of total exposed dose to annual dose resulted from the environmental radioactivity. Determination of the annual dose level of an archaeological area is one of the most important parameter in calculating the archaeological age of the sample using luminescence techniques. Therefore, the knowledge of the concentrations of the natural radionuclides is important since naturally occurring radioactivity provides major contribution to the annual dose. The natural radioactivity is originated from natural radionuclides consisting mainly of 2 38U, 2 32Th and 4 0K isotopes together with their daughters in soils. In this study, annual dose level of the archaeological site was determined with two different methods: an indirect method that is determining the concentrations of the naturally occurring radioactive elements using gamma spectroscopy and a direct method that uses thermoluminescence dosimeters. Soil samples were collected from the Yesilova Hoeyuek archaeological site located in Izmir City at the Aegean Region of Turkey. The concentrations of the natural radioactivity ( 2 38U, 2 32Th and 4 0K) in soil samples were determined using 3 x 3 N aI (Tl) γ-ray spectrometry system. In direct method, Al 2 O 3 :C thermoluminescence dosimeters (TLD's) were used. These dosimeters were chosen because of their sensitivity and usability in dating studies. They were buried in same archaeological site, 30 cm depth from the soil surface for 30 days period. The luminescence intensity of Al 2 O 3 :C dosimeters was measured by a TLD reader and the dose level was calculated by the luminescence signals emitted by the dosimeters. The results obtained from natural radionuclides and Al 2 O 3 :C thermoluminescence dosimeters were compared and the source of the differences between two methods were discussed

  2. Dose measurement of fast electrons with a modified Fricke solution

    International Nuclear Information System (INIS)

    Nemec, H.W.; Roth, J.; Luethy, H.

    1975-01-01

    A combination of two different modifications indicated in the literature about the ferrosulfate dosimetry is given. This permits a dose measurement which shows compared to the usual Fricke dosimetry above all following advantages: dose specification related to water; displacement of the absorption maximum in the perceptible spectral sphere; increase of the sensibility and lower influence of pollutions. The molar coefficient of extinction of the modified solution has been determined from 60 Co gamma irradiation and is epsilonsub(m) = 1.46 x 10 4 l x Mol -1 x cm -1 . The increase of extinction which has been measured with this method after the irradiation with 18 MeV electrons occurs linearly within the studied region to 1,200 rd at least, the G-value is 15.5. The indicated method renders possible a relative simple calibration of the ionization chambers used in the practice. (orig.) [de

  3. Dose Measurements in a 20-J Repetitive Plasma Focus

    Science.gov (United States)

    Goudarzi, S.; Babaee, H.; Esmaeli, A.; Nasiri, A.; Mazandarani, A.

    2018-02-01

    In this article, the results of X-ray dose measurements executed using thermoluminescent dosimeters in experiments with a very small (20 J) repetitive plasma focus device named SORENA-1 are presented and analyzed. The working gas in these experiments was Argon. Also, pinch formation in experiments with this device has been observed. This device has been designed and constructed in Plasma and Nuclear Fusion Research School of Nuclear Science and Technology Research Institute of Iran. From these results, it is concluded that we can do experiments with this device using Ar as working gas all over the working days of year, and a good symmetry for measured dose around the device has been seen.

  4. The Content Validity of a Chemotherapy-Induced Peripheral Neuropathy Patient-Reported Outcome Measure

    Science.gov (United States)

    Lavoie Smith, Ellen M.; Haupt, Rylie; Kelly, James P.; Lee, Deborah; Kanzawa-Lee, Grace; Knoerl, Robert; Bridges, Celia; Alberti, Paola; Prasertsri, Nusara; Donohoe, Clare

    2018-01-01

    Purpose/Objectives To test the content validity of a 16-item version of the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire–Chemotherapy-Induced Peripheral Neuropathy (QLQ-CIPN20). Research Approach Cross-sectional, prospective, qualitative design. Setting Six outpatient oncology clinics within the University of Michigan Health System’s comprehensive cancer center in Ann Arbor. Participants 25 adults with multiple myeloma or breast, gynecologic, gastrointestinal, or head and neck malignancies experiencing peripheral neuropathy caused by neurotoxic chemotherapy. Methodologic Approach Cognitive interviewing methodology was used to evaluate the content validity of a 16-item version of the QLQ-CIPN20 instrument. Findings Minor changes were made to three questions to enhance readability. Twelve questions were revised to define unfamiliar terminology, clarify the location of neuropathy, and emphasize important aspects. One question was deleted because of clinical and conceptual redundancy with other items, as well as concerns regarding generalizability and social desirability. Interpretation Cognitive interviewing methodology revealed inconsistencies between patients’ understanding and researchers’ intent, along with points that required clarification to avoid misunderstanding. Implications for Nursing Patients’ interpretations of the instrument’s items were inconsistent with the intended meanings of the questions. One item was dropped and others were revised, resulting in greater consistency in how patients, clinicians, and researchers interpreted the items’ meanings and improving the instrument’s content validity. Following additional revision and psychometric testing, the QLQ-CIPN20 could evolve into a gold-standard CIPN patient-reported outcome measure. PMID:28820525

  5. Whole-body dose meters. Measurements of total activity

    International Nuclear Information System (INIS)

    Koeppe, P.; Klinikum Steglitz, Berlin

    1990-01-01

    By means of measurements using a whole-body dose meter, the course of the incorporation of radionuclides was established between April 1986 and May 1989 for unchanged conditions of alimentation, activity-conscious alimentation, and uniquely increased incorporation. Monitoring covered persons from the most different spheres of life. The incorporation is compared with the one resulting from nuclear weapons explosions in the atmosphere. (DG) [de

  6. Radiation dose measurement for patients and staff during cardiac catheterization

    International Nuclear Information System (INIS)

    Joda, H. H. M.

    2009-07-01

    The primary objective of this study was to determine the patient and staff dose during cardiac catheterization procedures in Ahmed Gasim Hospital, Khartoum Bahry. A survey of patient and staff exposure was performed covered 2 Cath Lab units from 2 manufacturers. The measurements involved 50 operations. The medical staff was monitored using TLD chips (LiF: Mg, Cu, P). The main operator who was closer to the patient and the x-ray tube, was monitored at six positions (forehead, neck chest - over the lead apron, waist - under the lead apron, leg, and hand), while the exposure to the assistant was measured at two positions (chest - over the lead apron, and hand), where the technologist and the circulator were monitored at one position (chest - over the lead apron). patient exposure was measured using the DAP meter. The main operator and the rest of the staff received 0.14, 0.01 mSv/y respectively. The estimated patient dose rate was found to be 125 mGy/min which considered higher than the recommended DRL for the continuous high mode fluoroscopy used in interventional radiology (100 mGy/min). The study concluded to the fact that the main operator received relatively high dose which is a direct result to the poor radiation protection in the department. (Author)

  7. Ionizing radiation population doses at Sao Paulo city, Brazil: open-pit gamma dose measurement

    International Nuclear Information System (INIS)

    Oliveira, Raimundo Enoch Rodrigues

    2001-01-01

    The effects of ionizing radiation to the human beings are well known for high and intermediate doses. As far as low level) radiation doses are concerned, there is no consensus. In order to get a better understanding of such effects it is necessary to assess the low doses with better accuracy. In this work, it was made an estimate of the annual ambient dose equivalent (H * (10)) to which the people are exposed in the city of Sao Paulo. Until now there are no data about it available in the literature. For the purpose of this evaluation, a map with various routes covering the largest and more representative area of the city was designed. The choice of points for data collection was made taking into account mainly the occupancy of the region. A portable gamma spectrometry system was used. It furnishes the rate of H * (10) and the measured gamma spectrum (in the range from 50 to 1670 keV) in the place of interest. The measurements were performed in a short time interval, since the gamma radiation arrives from a great extent of soil. Each measurement was done 1 m above the soil during 300 s. The rates of H * (10) varied from 33.1 to 152.3 nSv.h -1 , net values, obtained after subtraction of the cosmic rays contribution. The standard deviation was 22 n Sv.h -1 for an average for the city of Sao Paulo of 96.1(24) nSv.h -1 . In addition, average values of H * (10) rates for the city Health Divisions were calculated. Those values are not statistically equivalent and the whole set of data could not be treated as one, as the statistical Student test indicated a non homogeneity of the group of data. Hence it is necessary the accomplishment of a more detailed survey in order to verify the origin of the discrepancy. The mean value of H * (10) rate obtained for the city of Sao Paulo as converted to effective dose. in order to be compared with other places results It could be noticed that the annual average of effective dose for the city of Sao Paulo, 0.522(13) mSv, is superior to

  8. Measurement of peripheral electron temperature by electron cyclotron emission during the H-mode transition in JFT-2M tokamak

    International Nuclear Information System (INIS)

    Hoshino, Katsumichi; Yamamoto, Takumi; Kawashima, Hisato

    1987-01-01

    Time evolution and profile of peripheral electron temperature during the H-mode like transition in a tokamak plasma is measured using the second and third harmonic of electron cyclotron emission (ECE). The so called ''H-mode'' state which has good particle/energy confinement is characterized by sudden decrease in the spectral line intensity of deuterium molecule. Such a sudden decrease in the line intensity of D α with good energy confinement is found not only in divertor discharges, but also in limiter dischargs in JFT-2M tokamak. It is found by the measurement of ECE that the peripheral electron temperature suddenly increases in both of such phases. The relation between H-transition and the peripheral electron temperature or its profile is investigated. (author)

  9. Technology Development for Radiation Dose Measurement and Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Hwan; Chang, S. Y.; Lee, T. Y. (and others)

    2007-06-15

    The correction factors essential for the operation of In-Vivo counting system were produced and implemented into a field operation for the improvement of accuracy in measurement of the radioactivity inside a human body. The BiDAS2007 code which calculate an internal dose was developed by upgrading the former code prepared in the previous stage of this project. The method of using the multibioassy data, the maximum likelihood function and the Bayesian statistics were established to an internal dose based on the measurement data of radioactivity, intakes and retention of radioactivity in a human body and it can improve the accuracy in estimation of the intakes of radioactivity and the committed effective dose equivalent. In order to solve the problem of low detection efficiency of the conventional Bonner Sphere (BS) to a high energy neutron, the extended BS's were manufactured and the technique for neutron field spectrometry was established. The fast neutron and gamma spectrometry system with a BC501A scintillation detector was also prepared. Several neutron fluence spectra at several nuclear facilities were measured and collected by using the extended BS. The spectrum weighted responses of some neutron monitoring instruments were also derived by using these spectra and the detector response functions. A high efficient TL material for the neutron personal dosimeter was developed. It solved the main problem of low thermal stability and high residual dose of the commercial TLDs and has the sensitivity to neutron and to gamma radiation with 40 and 10 times higher respectively than them.

  10. The effects of high dose ionizing radiation on transcriptional regulation and paracrine signaling in human peripheral blood mononuclear cells

    International Nuclear Information System (INIS)

    Beer, L.

    2015-01-01

    While it has long been accepted that direct cell-cell interactions and the replacement of injured tissues with injected cells exerts therapeutic effects, it is currently believed that, in addition, paracrine factors released from different cell types activate cytoprotective and regenerative processes. Cells are now seen as bioreactors that produce and release soluble factors which might be used as therapeutics. We have previously shown that peripheral blood mononuclear cells (PBMCs) release a plethora of paracrine factors that enhance wound healing, attenuate myocardial damage following acute myocardial infarction, abolish microvascular obstruction, improve neurological outcome after acute ischemic stroke and spinal cord injury and protect mice from experimental autoimmune myocarditis. These PBMC derived paracrine factors may exert their effects via the induction of cytoprotective pathways, augmentation of angiogenesis, induction of NO-depended vasodilation and inhibition of VASP dependent platelet aggregation, as well as driving auto-reactive CD4+ cells into apoptosis. To enhance the cellular secretory capacity, treatments which induce stress responses, such as hypoxic preconditioning or ionizing irradiation (IR), have been developed. Although these effects have been evaluated in several disease states there is little data available on the cellular effects of ionizing irradiation on human PBMCs and their secretome. In this study, we have thus undertaken to investigate the effects of IR on human PBMCs in terms of the induction of transcriptional changes and release of pleiotropic paracrine factors. There are three primary aims of this doctoral thesis: 1. To investigate cellular processes activated or repressed in human PBMCs following high dose ionizing radiation (60Gy) and high density cell cultivation (25*10"6 cells/ml) for up to 24 hours. 2. To identify paracrine factors released from these cells using a multi-methodical biochemical/bioinformatics approach. 3

  11. A Retrospective Study Evaluating the Effect of Low Doses of Perineural Dexamethasone on Ropivacaine Brachial Plexus Peripheral Nerve Block Analgesic Duration.

    Science.gov (United States)

    Schnepper, Gregory D; Kightlinger, Benjamin I; Jiang, Yunyun; Wolf, Bethany J; Bolin, Eric D; Wilson, Sylvia H

    2017-09-23

    Examination of the effectiveness of perineural dexamethasone administered in very low and low doses on ropivacaine brachial plexus block duration. Retrospective evaluation of brachial plexus block duration in a large cohort of patients receiving peripheral nerve blocks with and without perineural dexamethasone in a prospectively collected quality assurance database. A single academic medical center. A total of 1,942 brachial plexus blocks placed over a 16-month period were reviewed. Demographics, nerve block location, and perineural dexamethasone utilization and dose were examined in relation to block duration. Perineural dexamethasone was examined as none (0 mg), very low dose (2 mg or less), and low dose (greater than 2 mg to 4 mg). Continuous catheter techniques, local anesthetics other than ropivacaine, and block locations with fewer than 15 subjects were excluded. Associations between block duration and predictors of interest were examined using multivariable regression models. A subgroup analysis of the impact of receiving dexamethasone on block duration within each block type was also conducted using a univariate linear regression approach. A total of 1,027 subjects were evaluated. More than 90% of brachial plexus blocks contained perineural dexamethasone (≤4 mg), with a median dose of 2 mg. Increased block duration was associated with receiving any dose of perineural dexamethasone (P block duration did not differ with very low- or low-dose perineural dexamethasone after controlling for other factors (P = 0.420). Perineural dexamethasone prolonged block duration compared with ropivacaine alone; however, duration was not greater with low-dose compared with very low-dose perineural dexamethasone. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  12. Environmental dose measurement with microprocessor based portable TLD reader

    International Nuclear Information System (INIS)

    Deme, S.; Apathy, I.; Feher, I.

    1996-01-01

    Application of TL method for environmental gamma-radiation dosimetry involves uncertainty caused by the dose collected during the transport from the point of annealing to the place of exposure and back to the place of evaluation. Should an accident occur read out is delayed due to the need to transport to a laboratory equipped with a TLD reader. A portable reader capable of reading out the TL dosemeter at the place of exposure ('in situ TLD reader') eliminates the above mentioned disadvantages. We have developed a microprocessor based portable TLD reader for monitoring environmental gamma-radiation doses and for on board reading out of doses on space stations. The first version of our portable, battery operated reader (named Pille - 'butterfly') was made at the beginning of the 80s. These devices used CaSO 4 bulb dosemeters and the evaluation technique was based on analogue timing circuits and analogue to digital conversion of the photomultiplier current with a read out precision of 1 μGy and a measuring range up to 10 Gy. The measured values were displayed and manually recorded. The version with an external power supply was used for space dosimetry as an onboard TLD reader

  13. Technical specification of the NRPB thermoluminescent dosemeter used for the measurement of body dose and skin dose

    CERN Document Server

    Shaw, K B

    1977-01-01

    This report specifies the NRPB thermoluminescent dosemeter used for the measurement of radiation dose in tissue at a depth of 700 mg cm sup - sup 2 (body dose) and at a depth of 5-10 mg cm sup - sup 2 (skin dose).

  14. Entrance surface dose measurements in pediatric radiological examinations

    International Nuclear Information System (INIS)

    Ribeiro, L.A.; Yoshimura, E.M.

    2008-01-01

    A survey of pediatric radiological examinations was carried out in a reference pediatric hospital of the city of Sao Paulo, in order to investigate the doses to children undergoing conventional X-ray examinations. The results showed that the majority of pediatric patients are below 4 years, and that about 80% of the examinations correspond to chest projections. Doses to typical radiological examinations were measured in vivo with thermoluminescent dosimeters (LiF: Mg, Ti and LiF: Mg, Cu, P) attached to the skin of the children to determine entrance surface dose (ESD). Also homogeneous phantoms were used to obtain ESD to younger children, because the technique uses a so small kVp that the dosimeters would produce an artifact image in the patient radiograph. Four kinds of pediatric examinations were investigated: three conventional examinations (chest, skull and abdomen) and a fluoroscopic procedure (barium swallow). Relevant information about kVp and mAs values used in the examinations was collected, and we discuss how these parameters can affect the ESD. The ESD values measured in this work are compared to reference levels published by the European Commission for pediatric patients. The results obtained (third-quartile of the ESD distribution) for chest AP examinations in three age groups were: 0.056 mGy (2-4 years old); 0.068 mGy (5-9 years old); 0.069 mGy (10-15 years old). All of them are below the European reference level (0.100 mGy). ESD values measured to the older age group in skull and abdomen AP radiographs (mean values 3.44 and 1.20 mGy, respectively) are above the European reference levels (1.5 mGy to skull and 1.0 mGy to abdomen). ESD values measured in the barium swallow examination reached 10 mGy in skin regions corresponding to thyroid and esophagus. It was noticed during this survey that some technicians use, improperly, X-ray fluoroscopy in conventional examinations to help them in positioning the patient. The results presented here are a

  15. Phantom's construction for dose measurement in brachytherapy

    International Nuclear Information System (INIS)

    Tri Harjanto; Hidayat Joko Puspito; Joko Triyanto

    2009-01-01

    In nuclear medicine, dose rate validation is the key for a successful process in therapy and diagnose of any deases. Therefore, the brachytherapy equipment being designed and constructed is to be validated its dose rate received by the radiated object. A phantom for such validation purpose is designed and constructed as a correct as if on site geometrical position of sources. The design of phantom consists of seven layers of flexi glass plates: 10 mm thick, 105 mm wide, and 280 mm length. All the plates are to be holed according to the size of the applicator to be used. Every surface of the flexi glass layers is grooved 1 mm wide, 1 mm depth, and 10 mm distance between the groove. The applicator inside the phantom is positioned at a certain reference for measurement. Every TLD installed has a fix position toward the reference coordinate and has an index number. By this system of phantom, the isodose system can be plotted. (author)

  16. Changes in peripheral blood level of regulatory T cells in patients with malignant melanoma during treatment with dendritic cell vaccination and low-dose IL-2

    DEFF Research Database (Denmark)

    Bjoern, J; Brimnes, M K; Andersen, M H

    2011-01-01

    In this study, changes in peripheral blood regulatory T cell (Treg) levels were evaluated in 46 progressive patients with melanoma treated with a dendritic cell-based vaccine and concomitant low-dose IFN-α and IL-2. The regulatory subset of CD4 T cells, characterized by CD25(high......) , was prospectively analysed in fresh blood, and treatment-associated quantitative and qualitative changes were analysed. By the 4th vaccine, patients showed a marked increase in CD4+ CD25(high) T cell subset from 6% to 22% (P...

  17. Changes in peripheral blood level of regulatory T cells in patients with malignant melanoma during treatment with dendritic cell vaccination and low-dose IL-2

    DEFF Research Database (Denmark)

    Bjoern, J; Brimnes, M K; Andersen, M H

    2011-01-01

    In this study, changes in peripheral blood regulatory T cell (Treg) levels were evaluated in 46 progressive patients with melanoma treated with a dendritic cell-based vaccine and concomitant low-dose IFN-a and IL-2. The regulatory subset of CD4 T cells, characterized by CD25(high......) , was prospectively analysed in fresh blood, and treatment-associated quantitative and qualitative changes were analysed. By the 4th vaccine, patients showed a marked increase in CD4+ CD25(high) T cell subset from 6% to 22% (P...

  18. Measurement and comparison of skin dose using OneDose MOSFET and Mobile MOSFET for patients with acute lymphoblastic leukemia.

    Science.gov (United States)

    Mattar, Essam H; Hammad, Lina F; Al-Mohammed, Huda I

    2011-07-01

    Total body irradiation is a protocol used to treat acute lymphoblastic leukemia in patients prior to bone marrow transplant. It is involved in the treatment of the whole body using a large radiation field with extended source-skin distance. Therefore measuring and monitoring the skin dose during the treatment is important. Two kinds of metal oxide semiconductor field effect transistor (OneDose MOSFET and mobile MOSEFT) dosimeter are used during the treatment delivery to measure the skin dose to specific points and compare it with the target prescribed dose. The objective of this study was to compare the variation of skin dose in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using OneDose MOSFET detectors and Mobile MOSFET, and then compare both results with the target prescribed dose. The measurements involved 32 patient's (16 males, 16 females), aged between 14-30 years, with an average age of 22.41 years. One-Dose MOSFET and Mobile MOSFET dosimetry were performed at 10 different anatomical sites on every patient. The results showed there was no variation between skin dose measured with OneDose MOSFET and Mobile MOSFET in all patients. Furthermore, the results showed for every anatomical site selected there was no significant difference in the dose delivered using either OneDose MOSFET detector or Mobile MOSFET as compared to the prescribed dose. The study concludes that One-Dose MOSFET detectors and Mobile MOSFET both give a direct read-out immediately after the treatment; therefore both detectors are suitable options when measuring skin dose for total body irradiation treatment.

  19. Eye lens dosimetry in interventional cardiology: Results of staff dose measurements and link to patient dose levels

    International Nuclear Information System (INIS)

    Antic, V.; Ciraj-Bjelac, O.; Rehani, M.; Aleksandric, S.; Arandjic, D.; Ostojic, M.

    2013-01-01

    Workers involved in interventional cardiology procedures receive high eye lens dose if protection is not used. Currently, there is no suitable method for routine use for the measurement of eye dose. Since most angiography machines are equipped with suitable patient dosemeters, deriving factors linking staff eye doses to the patient doses can be helpful. In this study the patient kerma-area product, cumulative dose at an interventional reference point and eye dose in terms of Hp(3) of the cardiologists, nurses and radiographers for interventional cardiology procedures have been measured. Correlations between the patient dose and the staff eye dose were obtained. The mean eye dose was 121 mSv for the first operator, 33 mSv for the second operator/nurse and 12 mSv for radiographer. Normalised eye lens doses per unit kerma-area product were 0.94 mSv Gy -1 cm -2 for the first operator, 0.33 mSv Gy -1 cm -2 for the second operator/nurse and 0.16 mSv Gy -1 cm -2 for radiographers. Statistical analysis indicated that there is a weak but significant (p < 0.01) correlation between the eye dose and the kerma-area product for all three staff categories. These values are based on a local practice and may provide useful reference for other studies for validation and for wider utilisation in assessing the eye dose using patient dose values. (authors)

  20. The Effect of High Dose Cholecalciferol on Arterial Stiffness and Peripheral and Central Blood Pressure in Healthy Humans

    DEFF Research Database (Denmark)

    Bressendorff, Iain; Brandi, Lisbet; Schou, Morten

    2016-01-01

    and central blood pressure and 24-hour ambulatory blood pressure. RESULTS: 22 subjects in the cholecalciferol arm and 18 subjects in the placebo arm completed the 16 weeks of follow-up. There was no difference in changes in PWV, AIx corrected for heart rate or central or peripheral blood pressure between...... and blood pressure in healthy normotensive adults. METHODS: 40 healthy adults were randomised in this double-blinded study to either oral cholecalciferol 3000 IU/day or matching placebo and were followed for 16 weeks to examine any effects on pulse wave velocity (PWV), augmentation index (AIx), peripheral...... the two groups. There was no correlation between serum 25-hydroxy vitamin D and any of these parameters. CONCLUSIONS: Oral cholecalciferol 3000 IU/day does not affect arterial stiffness or blood pressure after 16 weeks of treatment in healthy normotensive adults. TRIAL REGISTRATION: ClinicalTrials.gov NCT...

  1. Measurement of Intrafascicular Insertion Force of a Tungsten Needle into Peripheral Nerve

    National Research Council Canada - National Science Library

    Jensen, W

    2001-01-01

    Microfabricated silicon array structures, such as those being developed by the VSAMUEL consortium may one day provide inexpensive yet highly selective chronically implanted interfaces to the peripheral nervous system...

  2. Measurement of peripheral plasma using double probe in TRIAM-IM

    International Nuclear Information System (INIS)

    Yamagami, Masahiro; Kawasaki; Shoji; Jyotaki, Eriko; Fujita, Takaaki; Sakamoto, Mizuki; Nakamura, Kazuo; Nakamura, Yukio; Ito, Satoshi

    1994-01-01

    Behind the poloidal limiter of the TRIAM-IM, the change with time lapse of the electron temperature and the plasma density at the time of OH discharge was examined by using a double probe. Scrape-off plasma parameters, namely the correlations of electron temperature, plasma density and ion flux with main plasma parameters were obtained. It was found that scrape-off density is almost proportional to square of beam average electron density. Further, it was determined by calculation that the density on the outermost shell magnetic surface is about 1.5 x 10 15 /m 2 . In the TRIAM-IM, it is expected that accompanying the increase of plasma current at the time of OH discharge, the effects of thermal load and particle load given to the limiter and the first wall increase, and the increase of the metallic impurities due to sputtering becomes a serious problem. The merits of double probe method are explained. The objective of this experiment is to examine the temperature and density of the plasma that comes in contact with the limiter and the wall by determining the basic parameters of peripheral plasma at the time of OH discharge. In order to heighten the reliability of data, the examination was carried out from both aspects of hardware and software. The TRIAM-IM, double probe measuring system and its theory, applied voltage sweeping part, signal processing system, data processing system, and the experimental results of scrape-off layer parameters are described. (K.I.)

  3. Clinical application of a OneDose(TM) MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

    2006-01-01

    In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose(TM) in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs. (note)

  4. Clinical application of a OneDose MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast.

    Science.gov (United States)

    Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

    2006-07-21

    In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs.

  5. 3D measurement of absolute radiation dose in grid therapy

    International Nuclear Information System (INIS)

    Trapp, J V; Warrington, A P; Partridge, M; Philps, A; Leach, M O; Webb, S

    2004-01-01

    Spatially fractionated radiotherapy through a grid is a concept which has a long history and was routinely used in orthovoltage radiation therapy in the middle of last century to minimize damage to the skin and subcutaneous tissue. With the advent of megavoltage radiotherapy and its skin sparing effects the use of grids in radiotherapy declined in the 1970s. However there has recently been a revival of the technique for use in palliative treatments with a single fraction of 10 to 20 Gy. In this work the absolute 3D dose distribution in a grid irradiation is measured for photons using a combination of film and gel dosimetry

  6. Expression of Cellular Isoform of Prion Protein on the Surface of Peripheral Blood Lymphocytes Among Women Exposed to Low Doses of Ionizing Radiation

    International Nuclear Information System (INIS)

    Klucinski, P.; Martirosian, G.; Mazur, B.; Kaufman, J.; Hrycek, A.; Masluch, E.; Cieslik, P.

    2007-01-01

    Ionizing radiation affect the expression of adhesive and co-stimulation molecules in lymphocytes. The objective of this study was to determinate the effect of low doses of ionizing radiation on the expression of prion protein PrPc on the surface peripheral blood lymphocytes in the women operating X-ray equipment. In female workers and persons of the control group the PrPc expression on CD3 (T-lymphocytes), Cd4 (T-helper), CD8 (T-cytotoxic) and CD19 (B- lymphocytes), were tested. We conclude that in women operating X-ray equipment the relationship between low doses of ionizing radiation and expression of PrPc on lymphocytes does exist concerning CD3, CD4 and CD lymphocytes. (author)

  7. Measurement of wavefront aberrations in cortex and peripheral nerve using a two-photon excitation guidestar

    Science.gov (United States)

    Futia, Gregory L.; Fontaine, Arjun; McCullough, Connor; Ozbay, Baris N.; George, Nickolas M.; Caldwell, John; Restrepo, Diego; Weir, Richard; Gibson, Emily A.

    2018-02-01

    Neural-machine interfaces using optogenetics are of interest due to their minimal invasiveness and potential for parallel read in and read out of activity. One possible biological target for such an interface is the peripheral nerve, where axonlevel imaging or stimulation could greatly improve interfacing with artificial limbs or enable neuron/fascicle level neuromodulation in the vagus nerve. Two-photon imaging has been successful in imaging brain activity using genetically encoded calcium or voltage indicators, but in the peripheral nerve, this is severely limited by scattering and aberrations from myelin. We employ a Shack-Hartman wavefront sensor and two-photon excitation guidestar to quantify optical scattering and aberrations in peripheral nerves and cortex. The sciatic and vagus nerves, and cortex from a ChAT-Cre ChR-eYFP transgenic mouse were excised and imaged directly. In peripheral nerves, defocus was the strongest aberration followed by astigmatism and coma. Peripheral nerve had orders of magnitude higher aberration compared with cortex. These results point to the potential of adaptive optics for increasing the depth of two-photon access into peripheral nerves.

  8. Difference between ejection times measured at two different peripheral locations as a novel marker of vascular stiffness.

    Directory of Open Access Journals (Sweden)

    Yurie Obata

    Full Text Available Pulse wave velocity (PWV has been recommended as an arterial damage assessment tool and a surrogate of arterial stiffness. However, the current technology does not allow to measure PWV both continuously and in real-time. We reported previously that peripherally measured ejection time (ET overestimates ET measured centrally. This difference in ET is associated with the inherent vascular properties of the vessel. In the current study we examined ETs derived from plethysmography simultaneously at different peripheral locations and examined the influence of the underlying arterial properties on ET prolongation by changing the subject's position. We calculated the ET difference between two peripheral locations (ΔET and its corresponding PWV for the same heartbeat. The ΔET increased with a corresponding decrease in PWV. The difference between ΔET in the supine and standing (which we call ET index was higher in young subjects with low mean arterial pressure and low PWV. These results suggest that the difference in ET between two peripheral locations in the supine vs standing positions represents the underlying vascular properties. We propose ΔET in the supine position as a potential novel real-time continuous and non-invasive parameter of vascular properties, and the ET index as a potential non-invasive parameter of vascular reactivity.

  9. Dose changes of electrophoretic mobility of lymphocytes of rats' peripheral blood at 60Co gamma-radiation effect

    International Nuclear Information System (INIS)

    Nikitina, I.Yu.; Rodionova, N.K.; Pinchuk, L.B.; Lipskaya, A.I.; Roval', G.N.; Serkiz, Ya.I.

    1992-01-01

    As a result of the obtained data analysis two groups of animals with specific changes of lymphocyte mobility after irradiation with 100 and 400 cGy doses were found. Animals irradiated with 50 cGy doses reacted in a single manner. Apparently it is related with the value of animals' radiosensitivity. 6 refs.; 1 fig.; 1 table. (author)

  10. Comparison and analysis of BNCT radiation dose between gold wire and JCDS measurement

    International Nuclear Information System (INIS)

    Kageji, T.; Mizobuchi, Y.; Nagahiro, S.; Nakagawa, Y.; Kumada, Hiroaki

    2006-01-01

    We compared and evaluated boron neutron capture therapy (BNCT) radiation dose between gold wire measurement and JAERI Computational Dosimetry System (JCDS). Gold wire analysis demonstrates the actual BNCT dose though it dose not reflect the real the maximum and minimum dose in tumor tissue. We can conclude that JCDS is precise and high-reliable dose planning system for BNCT. (author)

  11. Measuring Vincristine-Induced Peripheral Neuropathy in Children with Acute Lymphoblastic Leukemia

    Science.gov (United States)

    Lavoie Smith, Ellen M.; Li, Lang; Hutchinson, Raymond J.; Ho, Richard; Burnette, W. Bryan; Wells, Elizabeth; Bridges, Celia; Renbarger, Jamie

    2014-01-01

    Background Vincristine-induced peripheral neuropathy (VIPN) is difficult to quantify in children. Objective The study objective was to examine the reliability, validity, and clinical feasibility of several VIPN measures for use in children with acute lymphoblastic leukemia. Interventions/Methods Children (N = 65) aged 1–18 years receiving vincristine at four academic centers participated in the study. Baseline and pre-vincristine VIPN assessments were obtained using the Total Neuropathy Score-Pediatric Vincristine (TNS-PV), the National Cancer Institute Common Terminology Criteria for Adverse Events, the Balis grading scale, and the FACES pain scale. TNS-PV scores (n = 806) were obtained over 15 weeks. Blood was obtained at several time-points to quantify pharmacokinetic parameters. Results Cronbach’s alpha for a reduced TNS-PV scale was 0.84. TNS-PV scores correlated with cumulative vincristine dosage (r = 0.53, p = 0.01), pharmacokinetic parameters (r = 0.41, p = 0.05), and grading scale scores (r = 0.46 – 0.52; p = 0.01). FACES scores correlated with the TNS-PV neuropathic pain item (r = 0.48; p = 0.01), and were attainable in all ages. A 2-item V-Rex score (vibration and reflex items) was the most responsive to change (es 0.65, p < 0.001). TNS-PV scores were attainable in 95% of children ≥ 6 years. Conclusions The TNS-PV is reliable and valid for measuring VIPN. It is sensitive to change over time (15 weeks) and feasible for use in children ≥ 6 years of age. Implications for Practice The TNS-PV may be a useful tool for assessing vincristine toxicity in children with acute lymphoblastic leukemia. PMID:23842524

  12. Dose Titration of Pregabalin in Patients with Painful Diabetic Peripheral Neuropathy: Simulation Based on Observational Study Patients Enriched with Data from Randomized Studies.

    Science.gov (United States)

    Alexander, Joe; Edwards, Roger A; Manca, Luigi; Grugni, Roberto; Bonfanti, Gianluca; Emir, Birol; Whalen, Edward; Watt, Stephen; Parsons, Bruce

    2018-03-01

    Achieving a therapeutic response to pregabalin in patients with painful diabetic peripheral neuropathy (pDPN) requires adequate upward dose titration. Our goal was to identify relationships between titration and response to pregabalin in patients with pDPN. Data were integrated from nine randomized, placebo-controlled clinical trials as well as one 6-week open-label observational study conducted by 5808 physicians (2642 patients with pDPN) in standard outpatient settings in Germany. These studies evaluated pregabalin for treatment of pDPN. Using these data, we examined "what if" scenarios using a microsimulation platform that integrates data from randomized and observational sources as well as autoregressive-moving-average with exogenous inputs models that predict pain outcomes, taking into account weekly changes in pain, sleep interference, dose, and other patient characteristics that were unchanging. Final pain levels were significantly different depending on dose changes (P titration regardless of baseline pain severity. Altogether, 78.5% of patients with pDPN had 0-1 dose change, and 15.2% had ≥ 2 dose changes. Simulation demonstrated that the 4.8% of inadequately titrated patients who did not improve/very much improve their pain levels would have benefited from ≥ 2 dose changes. Patient satisfaction with tolerability (range 90.3-96.2%) was similar, regardless of baseline pain severity, number of titrations, or extent of improvement, suggesting that tolerability did not influence treatment response patterns. Upward dose titration reduced pain in patients with pDPN who actually received it. Simulation also predicted pain reduction in an inadequately titrated nonresponder subgroup of patients had they actually received adequate titration. The decision not to uptitrate must have been driven by factors other than tolerability. Pfizer, Inc.

  13. Dose measurement, its distribution and individual external dose assessments of inhabitants in the high background radiation areas in China

    International Nuclear Information System (INIS)

    Morishima, Hiroshige; Koga, Taeko; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2000-01-01

    As a part of the China-Japan cooperative research on natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external exposure to natural radiation in the high background radiation areas (HBRA) of Yangjiang in Guangdong province and in the control areas (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by personal dosimeters, an indirect method was applied in which the exposed individual doses were estimated from the environmental radiation doses measured by survey meters and the occupancy factors of each hamlet. We analyzed the dose in the hamlets and the variation in the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and several hamlets of different dose levels in HBRA and Hampizai hamlet in CA. With these parameters, we estimated individual dose rates and compared them with those obtained from direct measurement using dosimeters carried by selected individuals. The results obtained are as follows. The environmental radiation doses are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiations. The indoor radiation doses were due to exposure from the natural radioactive nuclides in the building materials and were about two times as large as the outdoor radiation doses. The difference between indoor and outdoor doses was not observed in CA. The occupancy factor was influenced by the age of individuals and by the season of the year. The occupancy factor was higher for infants and aged individuals than for other age groups. This lead to higher dose rates of exposure to those age groups. A good correlation was observed between the dose assessed indirectly and that measured directly and the

  14. Dose measurement, its distribution and individual external dose assessments of inhabitants in the high background radiation areas in China

    Energy Technology Data Exchange (ETDEWEB)

    Morishima, Hiroshige; Koga, Taeko [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2000-10-01

    As a part of the China-Japan cooperative research on natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external exposure to natural radiation in the high background radiation areas (HBRA) of Yangjiang in Guangdong province and in the control areas (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by personal dosimeters, an indirect method was applied in which the exposed individual doses were estimated from the environmental radiation doses measured by survey meters and the occupancy factors of each hamlet. We analyzed the dose in the hamlets and the variation in the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and several hamlets of different dose levels in HBRA and Hampizai hamlet in CA. With these parameters, we estimated individual dose rates and compared them with those obtained from direct measurement using dosimeters carried by selected individuals. The results obtained are as follows. The environmental radiation doses are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiations. The indoor radiation doses were due to exposure from the natural radioactive nuclides in the building materials and were about two times as large as the outdoor radiation doses. The difference between indoor and outdoor doses was not observed in CA. The occupancy factor was influenced by the age of individuals and by the season of the year. The occupancy factor was higher for infants and aged individuals than for other age groups. This lead to higher dose rates of exposure to those age groups. A good correlation was observed between the dose assessed indirectly and that measured directly and the

  15. Radiotherapy high energy surface dose measurements: effects of chamber polarity

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: The effects of chamber polarity have been investigated for the measurement of 6MV and 18MV x-ray surface dose using a parallel plate ionization chamber. Results have shown that a significant difference in measured ionization is recorded between to polarities at 6MV and 18MV at the phantom surface. A polarity ratio ranging from 1 062 to 1 005 is seen for 6MV x-rays at the phantom surface for field sizes 5cm x 5cm to 40cm x 40cm when comparing positive to negative polarity. These ratios range from 1.024 to 1.004 for 18MV x-rays with the same field sizes. When these charge reading are compared to the D max readings of the same polarity it is found that these polarity effects are minimal for the calculation of percentage dose results with variations being less than 1% of maximum. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  16. Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

    International Nuclear Information System (INIS)

    Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J.

    2015-01-01

    PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study

  17. Efficacy of a Radiation Absorbing Shield in Reducing Dose to the Interventionalist During Peripheral Endovascular Procedures: A Single Centre Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Power, S.; Mirza, M.; Thakorlal, A.; Ganai, B.; Gavagan, L. D.; Given, M. F.; Lee, M. J., E-mail: mlee@rcsi.ie [Beaumont Hospital, Imaging and Interventional Radiology Department (Ireland)

    2015-06-15

    PurposeThis prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures.Materials and MethodsA commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated.ResultsTLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142).ConclusionInitial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator’s body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

  18. Efficacy of a radiation absorbing shield in reducing dose to the interventionalist during peripheral endovascular procedures: a single centre pilot study.

    Science.gov (United States)

    Power, S; Mirza, M; Thakorlal, A; Ganai, B; Gavagan, L D; Given, M F; Lee, M J

    2015-06-01

    This prospective pilot study was undertaken to evaluate the feasibility and effectiveness of using a radiation absorbing shield to reduce operator dose from scatter during lower limb endovascular procedures. A commercially available bismuth shield system (RADPAD) was used. Sixty consecutive patients undergoing lower limb angioplasty were included. Thirty procedures were performed without the RADPAD (control group) and thirty with the RADPAD (study group). Two separate methods were used to measure dose to a single operator. Thermoluminescent dosimeter (TLD) badges were used to measure hand, eye, and unshielded body dose. A direct dosimeter with digital readout was also used to measure eye and unshielded body dose. To allow for variation between control and study groups, dose per unit time was calculated. TLD results demonstrated a significant reduction in median body dose per unit time for the study group compared with controls (p = 0.001), corresponding to a mean dose reduction rate of 65 %. Median eye and hand dose per unit time were also reduced in the study group compared with control group, however, this was not statistically significant (p = 0.081 for eye, p = 0.628 for hand). Direct dosimeter readings also showed statistically significant reduction in median unshielded body dose rate for the study group compared with controls (p = 0.037). Eye dose rate was reduced for the study group but this was not statistically significant (p = 0.142). Initial results are encouraging. Use of the shield resulted in a statistically significant reduction in unshielded dose to the operator's body. Measured dose to the eye and hand of operator were also reduced but did not reach statistical significance in this pilot study.

  19. The effects of increasing doses of MK-467, a peripheral alpha(2)-adrenergic receptor antagonist, on the cardiopulmonary effects of intravenous dexmedetomidine in conscious dogs.

    Science.gov (United States)

    Honkavaara, J M; Restitutti, F; Raekallio, M R; Kuusela, E K; Vainio, O M

    2011-08-01

    Different doses of MK-467, a peripheral alpha(2)-adrenergic receptor antagonist, with or without dexmedetomidine were compared in conscious dogs. Eight animals received either dexmedetomidine (10 μg/kg [D]), MK-467 (250 μg/kg [M250] or dexmedetomidine (10 μg/kg) with increasing doses of MK-467 (250 μg/kg [DM250], 500 μg/kg [DM500] and 750 μg/kg [DM750], respectively). Treatments were given intravenously (i.v.) in a randomized, crossover design with a 14-day washout period. Systemic hemodynamics and arterial blood gas analyses were recorded at baseline and at intervals up to 90 min after drugs administration. Dexmedetomidine alone decreased heart rate, cardiac index and tissue oxygen delivery and increased mean arterial pressure and systemic vascular resistance 5 min after administration. DM250 did not completely prevent these early effects, while DM750 induced a decrease in mean arterial pressure. With DM500, systemic hemodynamics remained stable throughout the observational period. MK-467 alone increased cardiac index and tissue oxygen delivery and had no deleterious adverse effects. No differences in arterial blood gases were observed between treatments that included dexmedetomidine. It was concluded that MK-467 attenuated or prevented dexmedetomidine's systemic hemodynamic effects in a dose-dependent manner when given simultaneously i.v. but had no effect on the pulmonary outcome in conscious dogs. A 50:1 dose ratio (MK-467:dexmedetomidine) induced the least alterations in cardiovascular function. © 2010 Blackwell Publishing Ltd.

  20. Randomized controlled trial comparing different single doses of intravenous paracetamol for placement of peripherally inserted central catheters in preterm infants

    NARCIS (Netherlands)

    D.W.E. Roofthooft (Daniella); S.H. Simons (Sinno); R.A. Lingen (Richard); D. Tibboel (Dick); J.N. van den Anker (John); I.K.M. Reiss (Irwin); M. van Dijk (Monique)

    2017-01-01

    markdownabstract__Background:__ The availability of a safe and effective pharmacological therapy to reduce procedural pain in preterm infants is limited. The effective analgesic single dose of intravenous paracetamol in preterm infants is unknown. Comparative studies on efficacy of different

  1. Measurements and calculations of doses from radioactive particles

    International Nuclear Information System (INIS)

    Leroux, J.B.; Herbaut, Y.

    1996-01-01

    Three Mile Island (TMI) and Tchernobyl reactor accidents have revealed the importance of the skin exposure to beta radiation produced by small high activity sources, named 'hot particles'. In nuclear power reactors, they may arise as small fragments of irradiated fuel or material which have been neutron activated by passing through the reactor co. In recent years, skin exposure to hot particles has been subject to different limitation criteria, formulated by AIEA, ICRP, NCRP working groups. The present work is the contribution of CEA Grenoble to a contract of the Commission of the European communities in cooperation with several laboratories: University of Birmingham, University of Toulouse and University of Montpellier with the main goal to check experiments and calculations of tissue dose from 60 Co radioactive particles. This report is split up into two parts: hot particle dosimetry close to a 60 Co spherical sample with an approximately 200 μm diameter, using a PTW extrapolation chamber model 233991; dose calculations from two codes: the Varskin Mod 2 computer code and the Hot 25 S2 Monte Carlo algorithm. The two codes lead to similar results; nevertheless there is a large discrepancy (of about 2) between calculations and PTW measurements which are higher by a factor of 1.9. At a 70 μm skin depth and for 1 cm 2 irradiated area, the total (β + γ) tissue dose rate delivered by a spherical ( φ = 200 μm) 60 Co source, in contact with skin, is of the order of 6.1 10 -2 nGy s -1 Bq -1 . (author)

  2. Passive Rn dose meters - measuring methods appropriate for large measurement series

    International Nuclear Information System (INIS)

    Urban, M.; Kiefer, H.

    1985-01-01

    Passive integrating measuring methods can be classified in several groups by their functioning principle, e.g. spray chambers or open chambers with nuclear trace detectors or TL detectors, open detectors, activated carbon dose meters with or without TL detectors. According to the functioning principle, only radon or radon and fission products can be detected. The lecture gives a survey of the present state of development of passive Rn dose meters. By the example of the Ra dose meter developed at Karlsruhe which was used in inquiry measurements carried out in Germany, Switzerland, the Netherlands, Belgium and Austria, etching technology, estimation of measuring uncertainties, reproducibility and fading behaviour shall be discussed. (orig./HP) [de

  3. Dose measurements in pulsed radiation fields with commercially available measuring components

    International Nuclear Information System (INIS)

    Friedrich, Sabrina; Hupe, Oliver

    2016-01-01

    Dose measurements in pulsed radiation fields with dosemeters using the counting technique are known to be inappropriate. Therefore, there is a demand for a portable device able to measure the dose in pulsed radiation fields. As a detector, ionisation chambers seem to be a good alternative. In particular, using a secondary standard ionisation chamber in combination with a reliable charge-measuring system would be a good solution. The Physikalisch-Technische Bundesanstalt (PTB) uses secondary standard ionisation chambers in combination with PTB-made measuring electronics for dose measurements at its reference fields. However, for general use, this equipment is too complex. For measurements on-site, a mobile special electronic system [Hupe, O. and Ankerhold, U. Determination of ambient and personal dose equivalent for personnel and cargo security screening. Radiat. Prot. Dosim. 121(4), 429-437 (2006)] has been used successfully. Still, for general use, there is a need for a much simpler but a just as good solution. A measuring instrument with very good energy dependence for H*(10) is the secondary standard ionisation chamber HS01. An easy-to-use and commercially available electrometer for measuring the generated charges is the UNIDOS by PTW Freiburg. Depending on the expected dose values, the ionisation chamber used can be selected. In addition, measurements have been performed by using commercially available area dosemeters, e.g. the Mini SmartION 2120S by Thermo Scientific, using an ionisation chamber and the Szintomat 6134 A/H by Automess, using a scintillation detector. (authors)

  4. Thallium-201 peripheral perfusion scans: feasibility of single-dose, single-day, rest and stress study

    International Nuclear Information System (INIS)

    Siegel, M.E.; Stewart, C.A.

    1981-01-01

    The distribution and redistribution kinetics of thallium-201 in the lower extremities were investigated to determine the relationships among the rest, stress, and delayed-stress perfusion studies. The distribution of perfusion when the tracer was administered at rest was compared with that when administered during stress, and the distribution 5 to 6 h after the stress injection. In nine of 10 subjects without peripheral vascular disease, the 5 to 6 h poststress redistribution pattern was unchanged from the stress pattern and was different from the rest pattern. However, in all patients with peripheral vascular disease, the delayed poststress perfusion distribution had greater similarity to the rest pattern and was substantially different from that noted immediately after stress. Using the time frame of this study, the stress and delayed-stress 201 Tl perfusion study of the lower extremities cannot be used to represent true rest perfusion. However, because of the similarity of the delayed-stress to the true rest distribution in abnormals, it may be clinically useful in defining rest and stress alterations

  5. Thallium-201 peripheral perfusion scans: feasibility of single-dose, single-day, rest and stress study

    International Nuclear Information System (INIS)

    Siegel, M.E.; Stewart, C.A.

    1981-01-01

    The distribution and redistribution kinetics of thallium-201 in the lower extremities were investigated to determine the relationships among the rest, stress, and delayed-stress perfusion studies. The distribution of perfusion when the tracer was administered at rest was compared with that when administered during stress, and the distribution 5--6 hr after the stress injection. The distribution was evaluated qualitatively by scanning and quantitatively by point counting. In nine of 10 subjects without peripheral vascular disease, the 5--6 poststress redistribution pattern was unchanged from the stress pattern and was different from the rest pattern. However, in all patients with peripheral vascular disease, the delayed poststress perfusion distribution had greater similarity to the rest pattern and was substantially different from that noted immediately after stress. Using the time frame of this study, the stress and delayed-stress 201 Tl perfusion study of the lower extremities cannot be used to represent true rest perfusion. However, because of the similarity of the delayed-stress to the true rest distribution in abnormals, it may be clinically useful in defining rest and stress alterations

  6. New values of some physical interaction coefficients for dose measurements

    International Nuclear Information System (INIS)

    Eisenlohr, H.H.; Zsdanszky, K.

    1986-01-01

    At its 8th meeting in 1985 Section I of the ''Comite Consultatif pour les Etalons de Mesure des Rayonnements lonisants'' (CCEMRI) to the ''Comite International des Poids et Mesures'' (CIPM) has put forward a recommendation on new values of some physical constants to be used for exposure and absorbed dose determinations (see Annex I). Implementation of this recommendation has some impact on the measurement of exposure, air kerma and absorbed dose, and may result in changes in calibration factors of dosimeters. This subject will be discussed in detail at the IAEA Workshop on Calibration Procedures in Dosimetry, to be held in Quito in October 1986. The following information may assist SSDLs in preparing themselves for the expected changes of calibration factors. The recommendation has been caused by new numerical values of some physical constants which have become available recently. The two most important changes concern: a) S m,a , the ratio of the mean restricted collision mass stopping powers of the chamber material to that of air for electrons crossing the cavity, and b) W air /e, the mean energy required to produce an ion pair in air per electron charge, for electrons emitted by radioactive sources or produced by photon absorption

  7. Relationship Between Peripheral and Psychophysical Measures of Amplitude Modulation Detection in Cochlear Implant Users.

    Science.gov (United States)

    Tejani, Viral D; Abbas, Paul J; Brown, Carolyn J

    trend is inconsistent with the physiologic measures. For a fixed modulation frequency, correlations were observed between MDTs and MRAs; this trend was evident at all frequencies except 1000 Hz (although only statistically significant for 250 and 500 Hz AM rates), possibly an indication of central limitations in processing of high modulation frequencies. Finally, peripheral responses were larger and psychophysical thresholds were lower in the apical electrodes relative to basal and medial electrodes, which may reflect better cochlear health and neural survival evidenced by lower preoperative low-frequency audiometric thresholds and steeper growth of neural responses in ECAP amplitude growth functions for apical electrodes. Robust ECAPs were recorded for all modulation frequencies tested. ECAP amplitudes varied sinusoidally, reflecting the periodicity of the modulated stimuli. MRAs increased as the modulation frequency increased, a trend we attribute to neural adaptation. For low modulation frequencies, there are multiple current steps between the peak and valley of the modulation cycle, which means successive stimuli are more similar to one another and neural responses are more likely to adapt. Higher MRAs were correlated with lower psychophysical thresholds at low modulation frequencies but not at 1000 Hz, implying a central limitation to processing of modulated stimuli.

  8. Radiation dosemeters and ambient dose rate measuring systems

    International Nuclear Information System (INIS)

    Maushart, R.

    1985-01-01

    The manufacturers have got the feeling that the PTB only reluctantly accepts complex dosimetric systems or systems with modern digital and microprocessor technology. Especially the fact that the PTB demands a restriction to a defined system configuration which must not be changed after design approval is felt to be a severe handicap. The rigid frame of design qualification forces manufacturers to adopt a two-tier development line, at least for ambient dose rate measuring systems, and frequently it is not necessarily the 'nature' system, i.e. equipment with modern technology, that is sent in to the PTB for testing. The way of solving the problem could be that PTB more readily accepts less familiar technologies, for instance by more frequently approving equipment at least preliminarily or for a restricted period of time, in order to collect experience. Another way could be to grant licence for system components, especially detectors. (orig./HP) [de

  9. Dose measurement during defectoscopic work using electronic personal dosimeters

    International Nuclear Information System (INIS)

    Smoldasova, J.

    2008-01-01

    Personal monitoring of the external radiation of radiation, personnel exposed to sources of ionizing radiation at a workplace is an important task of the radiological protection. Information based on the measured quantities characterizing the level of the exposure of radiation personnel enable to assess the optimum radiological protection at the relevant workplace and ascertain any deviation from the normal operation in time. Different types of personal dosimeters are used to monitor the external radiation of radiation personnel. Basically, there are two types of dosimeters, passive and active (electronic). Passive dosimeters provide information on the dose of exposure after its evaluation, while electronic dosimeters provide this information instantly. The goal of the work is to compare data acquired during different working activities using the DMC 2000 XB electronic dosimeters and the passive film dosimeters currently used at the defectoscopic workplace. (authors)

  10. Dosimetric evaluation of the OneDoseTM MOSFET for measuring kilovoltage imaging dose from image-guided radiotherapy procedures.

    Science.gov (United States)

    Ding, George X; Coffey, Charles W

    2010-09-01

    The purpose of this study is to investigate the feasibility of using a single-use dosimeter, OneDose MOSFET designed for in vivo patient dosimetry, for measuring the radiation dose from kilovoltage (kV) x rays resulting from image-guided procedures. The OneDose MOSFET dosimeters were precalibrated by the manufacturer using Co-60 beams. Their energy response and characteristics for kV x rays were investigated by using an ionization chamber, in which the air-kerma calibration factors were obtained from an Accredited Dosimetry Calibration Laboratory (ADCL). The dosimetric properties have been tested for typical kV beams used in image-guided radiation therapy (IGRT). The direct dose reading from the OneDose system needs to be multiplied by a correction factor ranging from 0.30 to 0.35 for kilovoltage x rays ranging from 50 to 125 kVp, respectively. In addition to energy response, the OneDose dosimeter has up to a 20% reduced sensitivity for beams (70-125 kVp) incident from the back of the OneDose detector. The uncertainty in measuring dose resulting from a kilovoltage beam used in IGRT is approximately 20%; this uncertainty is mainly due to the sensitivity dependence of the incident beam direction relative to the OneDose detector. The ease of use may allow the dosimeter to be suitable for estimating the dose resulting from image-guided procedures.

  11. Effect of chronic low dose natural radiation in human peripheral blood mononuclear cells: Evaluation of DNA damage and repair using the alkaline comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.R. Vivek, E-mail: prvkumar06@gmail.com [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Seshadri, M. [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Jaikrishan, G. [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Das, Birajalaxmi [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-05-15

    Highlights: • Effect of chronic low dose natural radiation in radio adaptive response studied. • PBMCs of subjects from NLNRA and HLNRA were challenged with gamma radiation. • DNA damage and repair in PBMCs was compared using the alkaline comet assay. • Significant reduction in DNA damage in subjects of high dose group from HLNRA noted. • Probable induction of an in vivo radio adaptive response in subjects from HLNRA. - Abstract: This study investigates whether peripheral blood mononuclear cells (PBMCs) from inhabitants of Kerala in southwest India, exposed to chronic low dose natural radiation in vivo (>1 mSv year{sup −1}), respond with a radioadaptive response to a challenging dose of gamma radiation. Toward this goal, PBMCs isolated from 77 subjects from high-level natural radiation areas (HLNRA) and 37 subjects from a nearby normal level natural radiation area (NLNRA) were challenged with 2 Gy and 4 Gy gamma radiation. Subjects from HLNRA were classified based on the mean annual effective dose received, into low dose group (LDG) and high dose group (HDG) with mean annual effective doses of 2.69 mSv (N = 43, range 1.07 mSv year{sup −1} to 5.55 mSv year{sup −1}) and 9.62 mSv (N = 34, range 6.07 mSv year{sup −1} to17.41 mSv year{sup −1}), respectively. DNA strand breaks and repair kinetics (at 7 min, 15 min and 30 min after 4 Gy) were evaluated using the alkaline single cell gel electrophoresis (comet) assay. Initial levels of DNA strand breaks observed after either a 2 Gy or a 4 Gy challenging dose were significantly lower in subjects of the HDG from HLNRA compared to subjects of NLNRA (2 Gy, P = 0.01; 4 Gy, P = 0.02) and LDG (2 Gy P = 0.01; 4 Gy, P = 0.05). Subjects of HDG from HLNRA showed enhanced rejoining of DNA strand breaks (HDG/NLNRA, P = 0.06) during the early stage of repair (within 7 min). However at later times a similar rate of rejoining of strand breaks was observed across the groups (HDG, LDG and NLNRA). Preliminary results from

  12. Radiation dose measurements during kilovoltage-cone beam computed tomography imaging in radiotherapy

    Directory of Open Access Journals (Sweden)

    A Sathish Kumar

    2016-01-01

    Conclusion: Radiation dose to the eye, breast, and the surface of the pelvis have been arrived at during CBCT. The doses measured on patients agreed closely with those measured on humanoid phantom and with published values.

  13. Proton dose distribution measurements using a MOSFET detector with a simple dose-weighted correction method for LET effects.

    Science.gov (United States)

    Kohno, Ryosuke; Hotta, Kenji; Matsuura, Taeko; Matsubara, Kana; Nishioka, Shie; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

    2011-04-04

    We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth-dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high-bias voltages. In order to accurately measure dose distributions, we developed a practical method for correcting the MOSFET response to proton beams. The detector was tested by examining lateral dose profiles formed by protons passing through an L-shaped bolus. The dose reproducibility, angular dependence and depth-dose response were evaluated using a 190 MeV proton beam. Depth-output curves produced using the MOSFET detectors were compared with results obtained using an ionization chamber (IC). Since accurate measurements of proton dose distribution require correction for LET effects, we developed a simple dose-weighted correction method. The correction factors were determined as a function of proton penetration depth, or residual range. The residual proton range at each measurement point was calculated using the pencil beam algorithm. Lateral measurements in a phantom were obtained for pristine and SOBP beams. The reproducibility of the MOSFET detector was within 2%, and the angular dependence was less than 9%. The detector exhibited a good response at the Bragg peak (0.74 relative to the IC detector). For dose distributions resulting from protons passing through an L-shaped bolus, the corrected MOSFET dose agreed well with the IC results. Absolute proton dosimetry can be performed using MOSFET detectors to a precision of about 3% (1 sigma). A thinner oxide layer thickness improved the LET in proton dosimetry. By employing correction methods for LET dependence, it is possible to measure absolute proton dose using MOSFET detectors.

  14. Capillaroscopy as an Outcome Measure for Clinical Trials on the Peripheral Vasculopathy in SSc—Is It Useful?

    Directory of Open Access Journals (Sweden)

    Maurizio Cutolo

    2010-01-01

    Full Text Available Peripheral microvascular impairment in systemic sclerosis (SSc may be easily detected and scored in a safe noninvasive way by nailfold videocapillaroscopy (NVC. The paper highlights clinical conditions related to SSc in which NVC may represent an outcome measure of therapeutical interventions, by elaborating on their already assessed relationship with the NVC patterns and eventually scores. The 3 important biological/clinical conditions are: the positivity for SSc-specific serum autoantibodies, the presence of SSc skin digital ulcers (DUs and of pulmonary arterial hypertension (PAH SSc associated. In conclusion, to the question if capillaroscopy (NVC may represent in SSc an outcome measure for clinical trials on the peripheral vasculopathy, based on the growing evidence and our detailed studies, the answer is positive. Recent therapeutic trials in SSc are confirming this role, and the experience is growing rapidly.

  15. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    International Nuclear Information System (INIS)

    Benton, E.R.; Deme, S.; Apathy, I.

    2006-01-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca 2 SO 4 :Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET ∞ H 2 O ≥ 10 keV/μm, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component ≥ 10 keV/μm measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/μm measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 μGy/day and dose equivalent rates ranging from 340 to 450 μSv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  16. Radiation-induced rib fracture after stereotactic body radiotherapy with a total dose of 54-56 Gy given in 9-7 fractions for patients with peripheral lung tumor: impact of maximum dose and fraction size.

    Science.gov (United States)

    Aoki, Masahiko; Sato, Mariko; Hirose, Katsumi; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Ono, Shuichi; Takai, Yoshihiro

    2015-04-22

    Radiation-induced rib fracture after stereotactic body radiotherapy (SBRT) for lung cancer has been recently reported. However, incidence of radiation-induced rib fracture after SBRT using moderate fraction sizes with a long-term follow-up time are not clarified. We examined incidence and risk factors of radiation-induced rib fracture after SBRT using moderate fraction sizes for the patients with peripherally located lung tumor. During 2003-2008, 41 patients with 42 lung tumors were treated with SBRT to 54-56 Gy in 9-7 fractions. The endpoint in the study was radiation-induced rib fracture detected by CT scan after the treatment. All ribs where the irradiated doses were more than 80% of prescribed dose were selected and contoured to build the dose-volume histograms (DVHs). Comparisons of the several factors obtained from the DVHs and the probabilities of rib fracture calculated by Kaplan-Meier method were performed in the study. Median follow-up time was 68 months. Among 75 contoured ribs, 23 rib fractures were observed in 34% of the patients during 16-48 months after SBRT, however, no patients complained of chest wall pain. The 4-year probabilities of rib fracture for maximum dose of ribs (Dmax) more than and less than 54 Gy were 47.7% and 12.9% (p = 0.0184), and for fraction size of 6, 7 and 8 Gy were 19.5%, 31.2% and 55.7% (p = 0.0458), respectively. Other factors, such as D2cc, mean dose of ribs, V10-55, age, sex, and planning target volume were not significantly different. The doses and fractionations used in this study resulted in no clinically significant rib fractures for this population, but that higher Dmax and dose per fraction treatments resulted in an increase in asymptomatic grade 1 rib fractures.

  17. Radiation-induced rib fracture after stereotactic body radiotherapy with a total dose of 54–56 Gy given in 9–7 fractions for patients with peripheral lung tumor: impact of maximum dose and fraction size

    International Nuclear Information System (INIS)

    Aoki, Masahiko; Sato, Mariko; Hirose, Katsumi; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Ono, Shuichi; Takai, Yoshihiro

    2015-01-01

    Radiation-induced rib fracture after stereotactic body radiotherapy (SBRT) for lung cancer has been recently reported. However, incidence of radiation-induced rib fracture after SBRT using moderate fraction sizes with a long-term follow-up time are not clarified. We examined incidence and risk factors of radiation-induced rib fracture after SBRT using moderate fraction sizes for the patients with peripherally located lung tumor. During 2003–2008, 41 patients with 42 lung tumors were treated with SBRT to 54–56 Gy in 9–7 fractions. The endpoint in the study was radiation-induced rib fracture detected by CT scan after the treatment. All ribs where the irradiated doses were more than 80% of prescribed dose were selected and contoured to build the dose-volume histograms (DVHs). Comparisons of the several factors obtained from the DVHs and the probabilities of rib fracture calculated by Kaplan-Meier method were performed in the study. Median follow-up time was 68 months. Among 75 contoured ribs, 23 rib fractures were observed in 34% of the patients during 16–48 months after SBRT, however, no patients complained of chest wall pain. The 4-year probabilities of rib fracture for maximum dose of ribs (Dmax) more than and less than 54 Gy were 47.7% and 12.9% (p = 0.0184), and for fraction size of 6, 7 and 8 Gy were 19.5%, 31.2% and 55.7% (p = 0.0458), respectively. Other factors, such as D2cc, mean dose of ribs, V10–55, age, sex, and planning target volume were not significantly different. The doses and fractionations used in this study resulted in no clinically significant rib fractures for this population, but that higher Dmax and dose per fraction treatments resulted in an increase in asymptomatic grade 1 rib fractures

  18. Estimation of Electron Dose Delivered by a 0.4 MeV Accelerator from Bremsstrahlung Dose Measurements

    DEFF Research Database (Denmark)

    Karadjov, A. G.; Hansen, Jørgen-Walther

    1980-01-01

    Determination of a 0.4 MeV electron dose from a bremsstrahlung dose measurement using a converter-detector system is considered. The detector used is a Frickle dosimeter, and the converters are aluminum, copper and lead foils. Optimal converter thickness is ascertained experimentally for each mat...... materials within a Z-range of 13–82. A linear relation is found between bremsstrahlung dose and electron dose ranging from 2 to 20 Mrad. Finally the effect of converter area on detector response is studied....

  19. Effect of body temperature on peripheral venous pressure measurements and its agreement with central venous pressure in neurosurgical patients.

    Science.gov (United States)

    Sahin, Altan; Salman, M Alper; Salman, A Ebru; Aypar, Ulka

    2005-04-01

    Previous studies suggest a correlation of central venous pressure (CVP) with peripheral venous pressure (PVP) in different clinical settings. The effect of body temperature on PVP and its agreement with CVP in patients under general anesthesia are investigated in this study. Fifteen American Society of Anesthesiologists I-II patients undergoing elective craniotomy were included in the study. CVP, PVP, and core (Tc) and peripheral (Tp) temperatures were monitored throughout the study. A total of 950 simultaneous measurements of CVP, PVP, Tc, and Tp from 15 subjects were recorded at 5-minute intervals. The measurements were divided into low- and high-Tc and -Tp groups by medians as cutoff points. Bland-Altman assessment for agreement was used for CVP and PVP in all groups. PVP measurements were within range of +/-2 mm Hg of CVP values in 94% of the measurements. Considering all measurements, mean bias was 0.064 mm Hg (95% confidence interval -0.018-0.146). Corrected bias for repeated measurements was 0.173 +/- 3.567 mm Hg (mean +/- SD(corrected)). All of the measurements were within mean +/- 2 SD of bias, which means that PVP and CVP are interchangeable in our setting. As all the measurements were within 1 SD of bias when Tc was > or = 35.8 degrees C, even a better agreement of PVP and CVP was evident. The effect of peripheral hypothermia was not as prominent as core hypothermia. PVP measurement may be a noninvasive alternative for estimating CVP. Body temperature affects the agreement of CVP and PVP, which deteriorates at lower temperatures.

  20. Mobilization and collection of CD34+ cells for autologous transplantation of peripheral blood hematopoietic progenitor cells in children: analysis of two different granulocyte-colony stimulating factor doses

    Directory of Open Access Journals (Sweden)

    Kátia Aparecida de Brito Eid

    2015-06-01

    Full Text Available Introduction: The use of peripheral hematopoietic progenitor cells (HPCs is the cell choice in autologous transplantation. The classic dose of granulocyte-colony stimulating factor (G- CSF for mobilization is a single daily dose of 10 µg/kg of patient body weight. There is a theory that higher doses of granulocyte-colony stimulating factor applied twice daily could increase the number of CD34+ cells collected in fewer leukapheresis procedures. Objective: The aim of this study was to compare a fractionated dose of 15 µg G-CSF/kg of body weight and the conventional dose of granulocyte-colony stimulating factor in respect to the number of leukapheresis procedures required to achieve a minimum collection of 3 × 106 CD34+ cells/kg body weight. Methods: Patients were divided into two groups: Group 10 - patients who received a single daily dose of 10 µg G-CSF/kg body weight and Group 15 - patients who received a fractioned dose of 15 µg G-CSF/kg body weight daily. The leukapheresis procedure was carried out in an automated cell separator. The autologous transplantation was carried out when a minimum number of 3 × 106 CD34+ cells/kg body weight was achieved. Results: Group 10 comprised 39 patients and Group 15 comprised 26 patients. A total of 146 apheresis procedures were performed: 110 (75.3% for Group 10 and 36 (24.7% for Group 15. For Group 10, a median of three (range: 1-7 leukapheresis procedures and a mean of 8.89 × 106 CD34+ cells/kg body weight (±9.59 were collected whereas for Group 15 the corresponding values were one (range: 1-3 and 5.29 × 106 cells/kg body weight (±4.95. A statistically significant difference was found in relation to the number of apheresis procedures (p-value <0.0001. Conclusions: To collect a minimum target of 3 × 106 CD34+ cells/kg body weight, the administration of a fractionated dose of 15 µg G-CSF/kg body weight significantly decreased the number of leukapheresis procedures performed.

  1. Measurement of peripheral venous catheter-related phlebitis: a cross-sectional study.

    Science.gov (United States)

    Göransson, Katarina; Förberg, Ulrika; Johansson, Eva; Unbeck, Maria

    2017-09-01

    Many instruments for measurement of peripheral venous catheter (PVC)-related phlebitis are available, but no consensus exists on their applicability in clinical practice. This absence of consensus affects the ability to identify and compare proportions of PVCs causing phlebitis within and across hospitals as the range varies between 2% and 62% in previous studies. We hypothesised that the instruments' ability to identify phlebitis varies. The aim of this study is to illustrate the complexity of application of phlebitis instruments to a clinical dataset. In this cross-sectional study, we applied 17 instruments for phlebitis identification (divided into three groups [instruments using definitions, severity rating systems, and scoring systems]) to PVCs in adult patients admitted to 12 inpatient units at Karolinska University Hospital in Sweden. We calculated the proportion of PVCs causing phlebitis on the basis of each instrument's minimum criterion for phlebitis. We also analysed each instrument's face validity. We compared proportions using the Z test. On the basis of data collected between Feb 2, 2009, and Feb 20, 2009, May 18, 2009, and June 5, 2009, and Feb 8, 2010, and Feb 26, 2010, we applied 17 instruments for phlebitis identification (eight instruments using definitions, seven severity rating systems, and two scoring systems) to 1175 observed PVCs in 1032 patients. The highest number of PVCs causing phlebitis generated by definitions was 137 (11·7%), by severity rating systems was 395 (33·6%), and by scoring systems was 363 (30·9%). The proportion generated by instruments using definitions was significantly different to that of both the severity rating (difference 21·9% [95% CI 18·6-25·2]; pphlebitis published in the scientific community. From a work environment and patient safety perspective, clinical staff engaged in PVC management should be aware of the absence of adequately validated instruments for phlebitis assessment. We suggest that researchers

  2. Target and peripheral dose from radiation sector motions accompanying couch repositioning of patient coordinates with the Gamma Knife® Perfexion™

    International Nuclear Information System (INIS)

    Tran, Tuan-Anh; Wu, Vincent; Malhotra, Harish; Steinman, James P.; Prasad, Dheerendra; Podgorsak, Matthew B.

    2011-01-01

    The GammaPlan ™ treatment planning system (TPS) does not fully account for shutter dose when multiple shots are required to deliver a patient’s treatment. The unaccounted exposures to the target site and its periphery are measured in this study. The collected data are compared to a similar effect from the Gamma Knife ® model 4C. A stereotactic head frame was attached to a Leksell ® 16 cm diameter spherical phantom; using a fiducial-box, CT images of the phantom were acquired and registered in the TPS. Measurements give the relationship of measured dose to the number of repositions with the patient positioning system (PPS) and to the collimator size. An absorbed dose of 10 Gy to the 50% isodose line was prescribed to the target site and all measurements were acquired with an ionization chamber. Measured dose increases with frequency of repositioning and with collimator size. As the radiation sectors transition between the beam on and beam off states, the target receives more shutter dose than the periphery. Shutter doses of 3.53±0.04 and 1.59±0.04 cGy/reposition to the target site are observed for the 16 and 8 mm collimators, respectively. The target periphery receives additional dose that varies depending on its position relative to the target. The radiation sector motions for the Gamma Knife ® Perfexion ™ result in an additional dose due to the shutter effect. The magnitude of this exposure is comparable to that measured for the model 4C

  3. Radiochromic Plastic Films for Accurate Measurement of Radiation Absorbed Dose and Dose Distributions

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Fidan, S.

    1977-01-01

    of dose rate (1–1014 rad s−1). Upon irradiation of the film, the profile of the radiation field is registered as a permanent colored image of the dose distribution. Unlike most other types of dyed plastic dose meters, the optical density produced by irradiation is in most cases stable for periods...... of many polymeric systems in industrial radiation processing. The result is that errors due to energy dependence of response of the radiation sensor are effectively reduced, since the spectral sensitivity of the dose meter matches that of the polymer of interest, over a wide range of photon and electron...

  4. Effects on peripheral and central blood pressure of cocoa with natural or high-dose theobromine: a randomized, double-blind crossover trial.

    Science.gov (United States)

    van den Bogaard, Bas; Draijer, Richard; Westerhof, Berend E; van den Meiracker, Anton H; van Montfrans, Gert A; van den Born, Bert-Jan H

    2010-11-01

    Flavanol-rich cocoa products have been reported to lower blood pressure. It has been suggested that theobromine is partially responsible for this effect. We tested whether consumption of flavanol-rich cocoa drinks with natural or added theobromine could lower peripheral and central blood pressure. In a double-blind, placebo-controlled 3-period crossover trial we assigned 42 healthy individuals (age 62±4.5 years; 32 men) with office blood pressure of 130 to 159 mm Hg/85 to 99 mm Hg and low added cardiovascular risk to a random treatment sequence of dairy drinks containing placebo, flavanol-rich cocoa with natural dose consisting of 106 mg of theobromine, or theobromine-enriched flavanol-rich cocoa with 979 mg of theobromine. Treatment duration was 3 weeks with a 2-week washout. The primary outcome was the difference in 24-hour ambulatory systolic blood pressure between placebo and active treatment after 3 weeks. The difference in central systolic blood pressure between placebo and active treatment was a secondary outcome. Treatment with theobromine-enriched cocoa resulted in a mean±SE of 3.2±1.1 mm Hg higher 24-hour ambulatory systolic blood pressure compared with placebo (Ptheobromine-enriched cocoa, laboratory peripheral systolic blood pressure was not different from placebo, whereas central systolic blood pressure was 4.3±1.4 mm Hg lower (P=0.001). Natural dose theobromine cocoa did not significantly change either 24-hour ambulatory or central systolic blood pressure compared with placebo. In conclusion, theobromine-enriched cocoa significantly increased 24-hour ambulatory systolic blood pressure while lowering central systolic blood pressure.

  5. Dose measurement, its distribution and individual external dose assessments of inhabitants on high background radiation area in China

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko; Morishima, Hiroshige [Kinki Univ., Atomic Energy Research Institute, Osaka (Japan); Tatsumi, Kusuo [Kinki Univ., Life Science Research Institute, Osaka (Japan); Nakai, Sayaka; Sugahara, Tsutomu [Health Research Foundation, Kyoto (Japan); Yuan Yongling [Labor Hygiene Institute of Hunan Prov. (China); Wei Luxin [Laboratory of Industorial Hygiene, Ministry of Health (China)

    2001-01-01

    As a part of the China-Japan cooperative research on the natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external to natural radiation in the high background radiation area (HBRA) of Yangjiang in Guangdong province and in the control area (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by the personal dosimeters, an indirect method was applied to estimate the exposed dose rates from the environmental radiation dose rates measured by survey meters and the occupancy factors of each hamlet. An individual radiation dose roughly correlates with the environmental radiation dose and the life style of the inhabitant. We have analyzed the environmental radiation doses in the hamlets and the variation of the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and the several hamlets of the different level doses in HBRA and Hampizai hamlet in CA. With these parameters, we made estimations of individual dose rates and compared them with those obtained from the direct measurement using dosimeters carried by selected individuals. The results obtained are as follows: (1) The environmental radiation dose rates are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiation. The indoor radiation dose rates were due to the exposure from the natural radioactive nuclides in the building materials and they were about twice higher than the outdoor radiation dose rates. This difference was not observed in CA. (2) The occupancy factor was affected by the age of individuals and the seasons of a year. Indoor occupancy factors were higher for infants and aged individuals than for other age groups. This lead to higher

  6. Dose measurement, its distribution and individual external dose assessments of inhabitants on high background radiation area in China

    International Nuclear Information System (INIS)

    Koga, Taeko; Morishima, Hiroshige; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2001-01-01

    As a part of the China-Japan cooperative research on the natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external to natural radiation in the high background radiation area (HBRA) of Yangjiang in Guangdong province and in the control area (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by the personal dosimeters, an indirect method was applied to estimate the exposed dose rates from the environmental radiation dose rates measured by survey meters and the occupancy factors of each hamlet. An individual radiation dose roughly correlates with the environmental radiation dose and the life style of the inhabitant. We have analyzed the environmental radiation doses in the hamlets and the variation of the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and the several hamlets of the different level doses in HBRA and Hampizai hamlet in CA. With these parameters, we made estimations of individual dose rates and compared them with those obtained from the direct measurement using dosimeters carried by selected individuals. The results obtained are as follows: 1) The environmental radiation dose rates are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiation. The indoor radiation dose rates were due to the exposure from the natural radioactive nuclides in the building materials and they were about twice higher than the outdoor radiation dose rates. This difference was not observed in CA. 2) The occupancy factor was affected by the age of individuals and the seasons of a year. Indoor occupancy factors were higher for infants and aged individuals than for other age groups. This lead to higher

  7. Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

    CERN Document Server

    Nakamura, T; Tonoike, K

    2003-01-01

    Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose b...

  8. Ten Years Evidence-Based High-Tech Acupuncture—A Short Review of Peripherally Measured Effects

    Directory of Open Access Journals (Sweden)

    Gerhard Litscher

    2009-01-01

    Full Text Available Since 1997, the Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine of Graz Medical University has been dealing with the demystification of acupuncture and examining, using non-invasive methods, how different stimulation modalities (manual needle acupuncture, laserneedle acupuncture and electro acupuncture affect peripheral and central functions. Laser is also an important instrument for acupuncture. One only needs to mention the treatment of children or of patients with needle phobia. The laserneedle acupuncture, which was examined scientifically for the first time in Graz, represents a new painless acupuncture method for which up to ten laserneedles are glued to the skin, but not stuck into it. This first part of the short review article summarizes some of the peripherally measured effects of acupuncture obtained at the Medical University of Graz within the last 10 years.

  9. Mobilization of peripheral blood progenitor cells by chemotherapy and granulocyte-macrophage colony-stimulating factor for hematologic support after high-dose intensification for breast cancer.

    Science.gov (United States)

    Elias, A D; Ayash, L; Anderson, K C; Hunt, M; Wheeler, C; Schwartz, G; Tepler, I; Mazanet, R; Lynch, C; Pap, S

    1992-06-01

    High-dose therapy with autologous marrow support results in durable complete remissions in selected patients with relapsed lymphoma and leukemia who cannot be cured with conventional dose therapy. However, substantial morbidity and mortality result from the 3- to 6-week period of marrow aplasia until the reinfused marrow recovers adequate hematopoietic function. Hematopoietic growth factors, particularly used after chemotherapy, can increase the number of peripheral blood progenitor cells (PBPCs) present in systemic circulation. The reinfusion of PBPCs with marrow has recently been reported to reduce the time to recovery of adequate marrow function. This study was designed to determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF)-mobilized PBPCs alone (without marrow) would result in rapid and reliable hematopoietic reconstitution. Sixteen patients with metastatic breast cancer were treated with four cycles of doxorubicin, 5-fluorouracil, and methotrexate (AFM induction). Patients responding after the first two cycles were administered GM-CSF after the third and fourth cycles to recruit PBPCs for collection by two leukapheresis per cycle. These PBPCs were reinfused as the sole source of hematopoietic support after high doses of cyclophosphamide, thiotepa, and carboplatin. No marrow or hematopoietic cytokines were used after progenitor cell reinfusion. Granulocytes greater than or equal to 500/microL was observed on a median of day 14 (range, 8 to 57). Transfusion independence of platelets greater than or equal to 20,000/microL occurred on a median day of 12 (range, 8 to 134). However, three patients required the use of a reserve marrow for slow platelet engraftment. In retrospect, these patients were characterized by poor baseline bone marrow cellularity and poor platelet recovery after AFM induction therapy. When compared with 29 historical control patients who had received the same high-dose intensification chemotherapy using autologous

  10. Process control and dosimetry applied to establish a relation between reference dose measurements and actual dose distribution

    International Nuclear Information System (INIS)

    Ehlerman, D.A.E.

    2001-01-01

    The availability of the first commercial dose level indicator prompted attempts to verify radiation absorbed dose to items under quarantine control (e.g. for insect disinfestation) by some indicator attached to these items. Samples of the new commercial dose level indicators were tested for their metrological properties using gamma and electron irradiation. The devices are suitable for the intended purpose and the subjective judgement whether the threshold dose was surpassed is possible in a reliable manner. The subjective judgements are completely backed by the instrumental results. Consequently, a prototype reader was developed; first tests were successful. The value of dose level indicators and the implications of its use for food or quarantine inspection depends on a link between dose measured (indicated) at the position of such indicator and the characteristic parameters of the frequency distribution of dose throughout the product load i.e. a box or a container or a whole batch of multiple units. Therefore, studies into variability and statistical properties of dose distributions obtained under a range of commercial situations were undertaken. Gamma processing at a commercial multipurpose contract irradiator, electron processing and bremsstrahlung applications at a largescale research facility were included; products were apples, potatoes, wheat, maize, pistachio. Studies revealed that still more detailed information on irradiation geometries are needed in order to render meaningful information from dose label indicators. (author)

  11. Process control and dosimetry applied to establish a relation between reference dose measurements and actual dose distribution

    Energy Technology Data Exchange (ETDEWEB)

    Ehlerman, D A.E. [Institute of Process Engineering, Federal Research Centre for Nutrition, Karlsruhe (Germany)

    2001-03-01

    The availability of the first commercial dose level indicator prompted attempts to verify radiation absorbed dose to items under quarantine control (e.g. for insect disinfestation) by some indicator attached to these items. Samples of the new commercial dose level indicators were tested for their metrological properties using gamma and electron irradiation. The devices are suitable for the intended purpose and the subjective judgement whether the threshold dose was surpassed is possible in a reliable manner. The subjective judgements are completely backed by the instrumental results. Consequently, a prototype reader was developed; first tests were successful. The value of dose level indicators and the implications of its use for food or quarantine inspection depends on a link between dose measured (indicated) at the position of such indicator and the characteristic parameters of the frequency distribution of dose throughout the product load i.e. a box or a container or a whole batch of multiple units. Therefore, studies into variability and statistical properties of dose distributions obtained under a range of commercial situations were undertaken. Gamma processing at a commercial multipurpose contract irradiator, electron processing and bremsstrahlung applications at a largescale research facility were included; products were apples, potatoes, wheat, maize, pistachio. Studies revealed that still more detailed information on irradiation geometries are needed in order to render meaningful information from dose label indicators. (author)

  12. Dose measurements in dental radiology using thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Chiara, Ana Claudia M. de; Costa, Alessandro M.; Pardini, Luiz Carlos

    2009-01-01

    The aim of this work was the implementation of a code of practice for dosimetry in dental radiology using the technique of thermoluminescent dosimetry. General principles for the use of thermoluminescent dosimeters were followed. The irradiations were performed using ten X-ray equipment for intra-oral radiography and an X-ray equipment for panoramic radiography. The incident air kerma was evaluated for five different exposure times used in clinical practice for intra-oral radiographs. Using a backscatter factor of 1.2, it was observed that approximately 40% of the entrance skin dose values found for intra-oral radiographs are above the diagnostic reference level recommended in national regulation. Different configurations of voltage and current were used representing the exposure as a child, woman and man for panoramic radiographs. The results obtained for the air kerma area product were respectively 53.3 +- 5.2 mGy.cm 2 , 101.5 +- 9.5 mGy.cm 2 and 116.8 +- 10.4 mGy.cm 2 . The use of thermoluminescent dosimetry requires several procedures before a result is recorded. The use of dosimeters with ionization chambers or semiconductors provides a simple and robust method for routine measurements. However, the use of thermoluminescent dosimetry can be of great value to large-scale surveys to establish diagnostic reference levels. (author)

  13. Dose rate measurement of a cobalt source 'Issledovatel' by means of Fricke dosimeter

    CERN Document Server

    Peimel-Stuglik, Z

    2001-01-01

    The results of measurements leading to the elaboration of a reliable and accurate dose rate determination for a cobalt irradiator 'Issledovatel' were presented. The dose measurements were done by means of classic Fricke dosimeter. The conclusions from measurements can be useful also for the dosimetry of other kinds of cobalt irradiators. The measurements were performed by a newly employed Laboratory for Measurements of Technological Doses staff and were a practical test of their proficiency in gamma ray dosimetry.

  14. Ex vivo measurement of calpain activation in human peripheral blood lymphocytes by detection of immunoreactive products of calpastatin degradation.

    Directory of Open Access Journals (Sweden)

    Jacek M Witkowski

    2008-01-01

    Full Text Available Limited proteolysis of multiple intracellular proteins by endogenous Ca-dependent cysteine proteases--calpains--is an important regulatory mechanism for cell proliferation, apoptosis etc. Its importance for cellular functions is stressed by existence of endogenous calpain inhibitors--calpastatins. The calpain-calpastatin system within living cells is in a fragile balance, which depends on both partners. The interdependence of calpain--a protease--and calpastatin--an endogenous inhibitor and at the same time a substrate for this enzyme makes any assessment of actual activity of this enzyme in the cells very difficult. In this work we made an attempt to estimate and compare the activity of calpain in human peripheral blood lymphocytes by assessing the levels of limited proteolysis of calpastatin in these cells by western blot, while at the same time the levels of calpain protein inside these cells was measured by flow cytometry. Our results indicate that it is possible to compare (semi-quantitatively the activities of calpain in peripheral blood CD4+ and CD19+ lymphocytes from various donors that way. Preliminary results showed that calpain activity is increased in the CD4+ T cells isolated from peripheral blood of rheumatoid arthritis patients as compared to control lymphocytes. Extremely high intrinsic activity of calpain was detected in chronic lymphocytic leukemia (CD19+ cells. All this confirms the detection of immunoreactive products of calpastatin as a good maker of endogenous calpain activity.

  15. Mobilizing peripheral blood stem cells with high-dose G-CSF alone is as effective as with Dexa-BEAM plus G-CSF in lymphoma patients.

    Science.gov (United States)

    Kröger, N; Zeller, W; Fehse, N; Hassan, H T; Krüger, W; Gutensohn, K; Lölliger, C; Zander, A R

    1998-09-01

    We compared retrospectively the efficacy of granulocyte colony stimulating factor (G-CSF) alone with chemotherapy plus G-CSF in mobilizing CD34-positive cells in patients with malignant lymphoma. 35 patients underwent peripheral blood stem cell (PBSC) collection following mobilization either with 24 microg/kg G-CSF for 4 consecutive days (n = 18) or Dexa-BEAM chemotherapy plus 5 microg/kg G-CSF (n = 17). High-dose G-CSF was well tolerated with only slight bone pain and/or myalgia. The Dexa-BEAM therapy required hospitalization with a median duration of 21 d. The median number of apheresis procedures in both groups was two (range two to four), resulting in a median of 5.3 and 5.1 x 10(6) CD34+ cells/kg. No patients in the G-CSF group, but one in the Dexa-BEAM group, failed to reach the target of collecting >2.0 x 10(6) CD34+ cells/kg. The number of CFU-GM (10.4 v 6.0 x 10(5)/kg) and of BFU-E (10.6 v 4.5 x 10(5)/kg; P = 0.04) was higher in the G-CSF group than in the Dexa-BEAM group. A subset analysis of CD34+ cells was performed in 16 patients showing a higher mean of Thy-1 (CD90w) coexpression in the G-CSF than in the Dexa-BEAM group (4.8 v 1.8%, P = 0.12). Additionally the percentage of CD34+/CD38- cells was higher in the G-CSF group (10.66% v 8.8%). However, these differences were not statistically significant. The median time to leucocyte and platelet engraftment after high-dose chemotherapy was slightly shorter in the G-CSF than in the Dexa-BEAM group (9 v 10 and 12 v 13.5 d, respectively). These results demonstrate that high-dose G-CSF is as effective as Dexa-BEAM plus G-CSF in mobilizing peripheral blood stem cells and produces prompt engraftment. The major advantages of G-CSF mobilization were the safe outpatient self-application and the fixed-day apheresis.

  16. Peripheral nerve MRI: precision and reproducibility of T2*-derived measurements at 3.0-T. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Tagliafico, Alberto [University of Genoa, Institute of Anatomy, Department of Experimental Medicine, Genoa (Italy); Bignotti, Bianca; Martinoli, Carlo [University of Genoa, Radiology Department, Genoa, Genova (Italy); Tagliafico, Giulio [CNR-IMATI, Consiglio Nazionale delle Ricerche, Istituto di Matematica Applicata e Tecnologie Informatiche, Genova (Italy)

    2015-05-01

    To prospectively evaluate the precision and reproducibility of T2*-derived measurements of the peripheral nerves. The study was approved by the local ethics committee and written informed consent was obtained. Bilateral upper and lower limb MRI examination was performed in 40 healthy subjects on a 3.0-T scanner. MRI protocol included T1-turbo spin-echo, T2-turbo spin-echo with fat suppression, and multiecho gradient recalled echo. Measurements of T2* times on T2* maps at different anatomical levels were performed. Three authors measured independently and in different sessions at baseline and after 4 weeks. Non-parametric tests and Bland-Altman statistics were used. Minimum and maximum percentage variability were 10 % and 19 % for T2* (84-91 % of reproducibility). Maximum values of minimum detectable differences between limbs was 16 % (with 95 % CI: 2-37). Intra- and inter-observer agreement of the three radiologists for T2* was considered good. Evaluating the combined influence of the observer and of the repeated measurements the reproducibility was 87-98 %. T2* measurement of the peripheral nerves is precise and reproducible. The healthy contralateral side can be used as an internal control. Variations in T2* values up to 16 % have to be considered. (orig.)

  17. Dose measurements with a HPGe detector - a technical manual

    Energy Technology Data Exchange (ETDEWEB)

    Lidstroem, K.; Nordenfors, C.; Aagren, G

    2000-06-01

    This paper is a technical manual for estimations of dose based on a gamma spectrum. The method used is based on the Monte Carlo code EGS4. Since dose estimations from spectra are specific for each detector, this work is performed on two mobile HPGe detectors at FOA NBC Defence in Umeaa. This technical manual describes the method used in three steps: Part 1 explains how to construct a model of the detector geometry and the specific material for a new detector. Part 2 describes the underlying work of Monte Carlo simulations of a detector given geometry and material. Part 3 describes dose estimations from a gamma spectrum.

  18. Calculations of two new dose metrics proposed by AAPM Task Group 111 using the measurements with standard CT dosimetry phantoms

    International Nuclear Information System (INIS)

    Li, Xinhua; Zhang, Da; Liu, Bob

    2013-01-01

    Purpose: AAPM Task Group 111 proposed to measure the equilibrium dose-pitch product D-caret eq for scan modes involving table translation and the midpoint dose D L (0) for stationary-table modes on the central and peripheral axes of sufficiently long (e.g., at least 40 cm) phantoms. This paper presents an alternative approach to calculate both metrics using the measurements of scanning the standard computed tomographic (CT) dosimetry phantoms on CT scanners.Methods: D-caret eq was calculated from CTDI 100 and ε(CTDI 100 ) (CTDI 100 efficiency), and D L (0) was calculated from D-caret eq and the approach to equilibrium function H(L) =D L (0)/D eq , where D eq was the equilibrium dose. CTDI 100 may be directly obtained from several sources (such as medical physicist's CT scanner performance evaluation or the IMPACT CT patient dosimetry calculator), or be derived from CTDI Vol using the central to peripheral CTDI 100 ratio (R 100 ). The authors have provided the required ε(CTDI 100 ) and H(L) data in two previous papers [X. Li, D. Zhang, and B. Liu, Med. Phys. 39, 901–905 (2012); and ibid. 40, 031903 (10pp.) (2013)]. R 100 was assessed for a series of GE, Siemens, Philips, and Toshiba CT scanners with multiple settings of scan field of view, tube voltage, and bowtie filter.Results: The calculated D L (0) and D L (0)/D eq in PMMA and water cylinders were consistent with the measurements on two GE CT scanners (LightSpeed 16 and VCT) by Dixon and Ballard [Med. Phys. 34, 3399–3413 (2007)], the measurements on a Siemens CT scanner (SOMATOM Spirit Power) by Descamps et al. [J. Appl. Clin. Med. Phys. 13, 293–302 (2012)], and the Monte Carlo simulations by Boone [Med. Phys. 36, 4547–4554 (2009)].Conclusions: D-caret eq and D L (0) can be calculated using the alternative approach. The authors have provided the required ε(CTDI 100 ) and H(L) data in two previous papers. R 100 is presented for a majority of multidetector CT scanners currently on the market, and can be

  19. Measurement of multi-slice computed tomography dose profile with the Dose Magnifying Glass and the MOSkin radiation dosimeter

    International Nuclear Information System (INIS)

    Lian, C.P.L.; Wong, J.H.D.; Young, A.; Cutajar, D.; Petasecca, M.; Lerch, M.L.F.; Rosenfeld, A.B.

    2013-01-01

    This study describes the application of two in-house developed dosimeters, the Dose Magnifying Glass (DMG) and the MOSkin dosimeter at the Centre for Medical Radiation Physics, University of Wollongong, Australia, for the measurement of CT dose profiles for a clinical diagnostic 16-slice MSCT scanner. Two scanner modes were used; axial mode and helical mode, and the effect of varying beam collimation and pitch was studied. With an increase in beam collimation in axial mode and an increase of CT pitch in helical mode, cumulative point dose at scanner isocentre decreased while FWHM increased. There was generally good agreement to within 3% between the acquired dose profiles obtained by the DMG and the film except at dose profile tails, where film over-responded by up to 30% due to its intrinsic depth dose dependence at low doses. -- Highlights: ► This study shows the CT beam profiles acquired with our institution's detectors. ► The DMG is a relative dosimeter calibrated to absolute MOSkin readings. ► There was good agreement between dose profiles acquired by the DMG and the film

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

    International Nuclear Information System (INIS)

    Geber, Therese; Gunnarsson, Mikael; Mattsson, Sören

    2011-01-01

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

  1. A phantom based method for deriving typical patient doses from measurements of dose-area product on populations of patients

    International Nuclear Information System (INIS)

    Chapple, C.-L.; Broadhead, D.A.

    1995-01-01

    One of the chief sources of uncertainty in the comparison of patient dosimetry data is the influence of patient size on dose. Dose has been shown to relate closely to the equivalent diameter of the patient. This concept has been used to derive a prospective, phantom based method for determining size correction factors for measurements of dose-area product. The derivation of the size correction factor has been demonstrated mathematically, and the appropriate factor determined for a number of different X-ray sets. The use of phantom measurements enables the effect of patient size to be isolated from other factors influencing patient dose. The derived factors agree well with those determined retrospectively from patient dose survey data. Size correction factors have been applied to the results of a large scale patient dose survey, and this approach has been compared with the method of selecting patients according to their weight. For large samples of data, mean dose-area product values are independent of the analysis method used. The chief advantage of using size correction factors is that it allows all patient data to be included in a survey, whereas patient selection has been shown to exclude approximately half of all patients. (author)

  2. Occupational dose measurement in interventional cardiology, dosimetry comparison study

    International Nuclear Information System (INIS)

    Ahmad, A.M.A.

    2008-05-01

    The number of cardiology interventional procedures has significantly increased recently. This is due to the reliability of the diagnostic equipment to diagnose many heart disease. In the procedures the x-ray used results in increasing radiation doses to the staff. The cardiologists and other staff members in interventional cardiology are usually working close to the area under examination and receive the dose primarily from scattered radiation from the patient. Therefore workers in interventional cardiology are expected to receive high doses. This study overviews the status of occupational exposure at the three cardiology centers at three different hospitals in Khartoum compared with that received by workers at other medical practices (radiotherapy, nuclear medicine and diagnostic radiology) in the Institute of Nuclear and Technology (INMO) at El Gezira. The TLD Harshaw 6600 reader was used in the assessment of effective dose for Hp (10). Two TLDs were used by each worker at the three cardiology centres, one worn under a protective apron and the other worn outside and above the apron as specified by the ICRP. Each worker at the other sections was facilitated with one dosimeter to be worn on the chest. The annual doses received by 14 cardiologists, 13 nurses and 9 technologists at the three cardiology centres were in the range: (0.84-4.77), (0.15-2.08), (0.32-1.10) mSv respectively. In the INMO the annual doses received by 7 doctors, 5 nurses and 14 technologists were in the range: (0.12-0.51), (0.11-0.65), (0.03-1.39) mSv respectively. The results showed that the annual doses received by the workers do not exceed 20 mSv. The study also indicated that doses received by workers in interventional cardiology, in particular the cardiologists are high compared to that received at the other medical sections.(Author)

  3. Measuring radiation exposure during percutaneous drainages: can shoulder dosemeters be used to estimate finger doses?

    International Nuclear Information System (INIS)

    Vehmas, Tapio; Tikkanen, Heikki

    1992-01-01

    To assess the need for extra finger dosemeters, radiologists' and assistants' radiation exposure at both shoulders and at the third fingers of both hands were recorded using thermoluminescent dosemeters during 27 interventional drainage procedures. Under couch screening was used. Mean dose rates were calculated by dividing dose by screening time. The radiologists' bilateral finger dose rates did not correlate with each other; nor did dose rates between the left shoulder and the right hand. The radiologists' dose rates at both shoulders, correlated with each other, as did shoulder dose rates with dose rates at the ispilateral hand. The right shoulder dose rates correlated with the left hand dose rates. The assistants' dose rates at places of measurement showed significant correlations with each other. (Author)

  4. 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)

  5. Global real-time dose measurements using the Automated Radiation Measurements for Aerospace Safety (ARMAS) system

    Science.gov (United States)

    Tobiska, W. Kent; Bouwer, D.; Smart, D.; Shea, M.; Bailey, J.; Didkovsky, L.; Judge, K.; Garrett, H.; Atwell, W.; Gersey, B.; Wilkins, R.; Rice, D.; Schunk, R.; Bell, D.; Mertens, C.; Xu, X.; Wiltberger, M.; Wiley, S.; Teets, E.; Jones, B.; Hong, S.; Yoon, K.

    2016-11-01

    The Automated Radiation Measurements for Aerospace Safety (ARMAS) program has successfully deployed a fleet of six instruments measuring the ambient radiation environment at commercial aircraft altitudes. ARMAS transmits real-time data to the ground and provides quality, tissue-relevant ambient dose equivalent rates with 5 min latency for dose rates on 213 flights up to 17.3 km (56,700 ft). We show five cases from different aircraft; the source particles are dominated by galactic cosmic rays but include particle fluxes for minor radiation periods and geomagnetically disturbed conditions. The measurements from 2013 to 2016 do not cover a period of time to quantify galactic cosmic rays' dependence on solar cycle variation and their effect on aviation radiation. However, we report on small radiation "clouds" in specific magnetic latitude regions and note that active geomagnetic, variable space weather conditions may sufficiently modify the magnetospheric magnetic field that can enhance the radiation environment, particularly at high altitudes and middle to high latitudes. When there is no significant space weather, high-latitude flights produce a dose rate analogous to a chest X-ray every 12.5 h, every 25 h for midlatitudes, and every 100 h for equatorial latitudes at typical commercial flight altitudes of 37,000 ft ( 11 km). The dose rate doubles every 2 km altitude increase, suggesting a radiation event management strategy for pilots or air traffic control; i.e., where event-driven radiation regions can be identified, they can be treated like volcanic ash clouds to achieve radiation safety goals with slightly lower flight altitudes or more equatorial flight paths.

  6. Oblique incidence of electron beams - comparisons between calculated and measured dose distributions

    International Nuclear Information System (INIS)

    Karcher, J.; Paulsen, F.; Christ, G.

    2005-01-01

    Clinical applications of high-energy electron beams, for example for the irradiation of internal mammary lymph nodes, can lead to oblique incidence of the beams. It is well known that oblique incidence of electron beams can alter the depth dose distribution as well as the specific dose per monitor unit. The dose per monitor unit is the absorbed dose in a point of interest of a beam, which is reached with a specific dose monitor value (DIN 6814-8[5]). Dose distribution and dose per monitor unit at oblique incidence were measured with a small-volume thimble chamber in a water phantom, and compared to both normal incidence and calculations of the Helax TMS 6.1 treatment planning system. At 4 MeV and 60 degrees, the maximum measured dose per monitor unit at oblique incidence was decreased up to 11%, whereas at 18MeV and 60 degrees this was increased up to 15% compared to normal incidence. Comparisons of measured and calculated dose distributions showed that the predicted dose at shallow depths is usually higher than the measured one, whereas it is smaller at depths beyond the depth of maximum dose. On the basis of the results of these comparisons, normalization depths and correction factors for the dose monitor value were suggested to correct the calculations of the dose per monitor unit. (orig.)

  7. Measurement of radiation dose to the eye-lens with bilateral whole brain irradiation

    International Nuclear Information System (INIS)

    Kim, Ki Hwan; Park, Charn Il; Kang, Wee Saing; Choo, Dong Woon

    1985-01-01

    In 40 patients with metastatic brain tumor and acute lymphoblastic leukemia received whole brain irradiation, the dose delivered to the eye lens was measured using T.L.D. chips applied on the eyes as usual shield. The dose to the eye lens was expressed the relative dose to the mid brain dose. Radiotherapy was administrated using Co-60 teletherapy with bilateral whole brain irradiation. The results are as follows: 1. The dose to the right eye from its incipient field is 16.6% of tumor dose while the dose to the same eye from the opposite field is 41.2%. On left eye, 19.2% from incipient field while 39.2% from the opposite field. 2. Total received dose to right and left eyes is 28.9%, 29.8% of tumor dose respectively. 3. Comparing lens shield group with orbit shield group dose is 22.5%, 15.8% of tumor dose, respectively. 4. The dose delivered to the eye lens in ipsilateral side depends upon internal scattering, location of lead shield and penetrating dose of lead in itself. The dose in contralateral side depends upon divergency of radiation beam and patient's malposition. 5. The dose to the eye lens should be less than 10% of tumor dose with adequate shield, also not missing the chance of leptomeningeal recurrence because of overshielding.

  8. Trend of collective dose and dose reduction measures of Mitsubishi Electric Corporation workers in nuclear power plants

    International Nuclear Information System (INIS)

    Yamato, I.; Nakayama, T.; Shimokawa, F.; Yamamoto, T.

    1996-01-01

    MELCO has supplied the reactor instrumentation control system, reactor coolant pump motors, turbine generator and central control system for the pressurized water type nuclear power plant. For the legal periodical inspection and repair work, MELCO has also received orders for the periodical inspection for 23 power plants (including 4 plants under construction) of 5 electric power companies, and executed the inspection work from the view point of preventive maintenance. The annual dose for MELCO's workers is liable to be decreased in spite of increased number of plants. The dose for new plant in particular is 50, or less as compared with that for conventional plant. This is because the measures taken for the conventional plant against the dose reduction is reflected upon the new plant. The dose reduction measures are taken for each system for which order was received. Such measures are mainly intended to improve the work procedures and equipment for reduction of work time in the radioactive area and to arrange the working process, so as to perform the work in such period when the dose level at the working environment is low. To enhance the workers' consciousness for reduction of dose, MELCO provided the workers with dose predictive training, and let them aware of such items known at the tool box briefing (TBX), which could realize the dose reduction for workers. MELCO has been positively promoting the activity to arrange the desirable work environment for extermination of 3Ks (giken, gitsui, titanai) or 3Ds (dangerous, difficult, dirty) including protection against radiation in corporation with electric power companies. (author)

  9. SU-G-BRB-14: Uncertainty of Radiochromic Film Based Relative Dose Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Devic, S; Tomic, N; DeBlois, F; Seuntjens, J [McGill University, Montreal, QC (Canada); Lewis, D [RCF Consulting, LLC, Monroe, CT (United States); Aldelaijan, S [King Faisal Specialist Hospital & Research Center, Riyadh (Saudi Arabia)

    2016-06-15

    Purpose: Due to inherently non-linear dose response, measurement of relative dose distribution with radiochromic film requires measurement of absolute dose using a calibration curve following previously established reference dosimetry protocol. On the other hand, a functional form that converts the inherently non-linear dose response curve of the radiochromic film dosimetry system into linear one has been proposed recently [Devic et al, Med. Phys. 39 4850–4857 (2012)]. However, there is a question what would be the uncertainty of such measured relative dose. Methods: If the relative dose distribution is determined going through the reference dosimetry system (conversion of the response by using calibration curve into absolute dose) the total uncertainty of such determined relative dose will be calculated by summing in quadrature total uncertainties of doses measured at a given and at the reference point. On the other hand, if the relative dose is determined using linearization method, the new response variable is calculated as ζ=a(netOD)n/ln(netOD). In this case, the total uncertainty in relative dose will be calculated by summing in quadrature uncertainties for a new response function (σζ) for a given and the reference point. Results: Except at very low doses, where the measurement uncertainty dominates, the total relative dose uncertainty is less than 1% for the linear response method as compared to almost 2% uncertainty level for the reference dosimetry method. The result is not surprising having in mind that the total uncertainty of the reference dose method is dominated by the fitting uncertainty, which is mitigated in the case of linearization method. Conclusion: Linearization of the radiochromic film dose response provides a convenient and a more precise method for relative dose measurements as it does not require reference dosimetry and creation of calibration curve. However, the linearity of the newly introduced function must be verified. Dave Lewis

  10. Electron beam dose measurements with alanine/ESR dosimeter

    International Nuclear Information System (INIS)

    Rodrigues, O. Jr.; Galante, O.L.; Campos, L.L.

    2001-01-01

    When the aminoacid alanine, CH 3 -CH(NH 2 )-COOH, is exposed to radiation field, stable free radicals are produced. The predominant paramagnetic specie found at room temperature is the CH 3 -CH-COOH. Electron Spin Resonance - ESR is a technique used for quantification and analysis of radicals in solid and liquid samples. The evaluation of the amount of produced radicals can be associated with the absorbed dose . The alanine/ESR is an established dosimetry method employed for high doses evaluation, it presents good performance for X-rays, gamma, electrons, and protons radiation detection. The High Doses Dosimetry Laboratory of Ipen developed a dosimetric system based on alanina/ESR that presents good characteristics for use in gamma fields such as: wide dose range from 10 to 10 5 Gy, low fading, low uncertainty (<5%), no dose rate dependence and non-destructive ESR single readout. The detector is encapsulated in a special polyethylene tube that reduces the humidity problems and improves the mechanical resistance. The IPEN dosimeter was investigated for application in electron beam fields dosimetry

  11. Validation of SEACAB Methodology with Frascati (FNG) Photon Dose Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tore, C.; Ortego, P.; Rodriguez Rivada, A.

    2014-07-01

    In the operation of the International Thermonuclear Experimental Reactor (ITER) the correct estimation of the gamma dose rate produced from the structural materials after shut down is one of the important safety parameter for hands-on maintenance. SEACAB, a rigorous 2-step (R2S) computational method has been developed for the calculation of residual dose in 3-D geometry with the use of the MCNP5 and of the ACAB (ACtivation ABacus) inventory code. The method is very efficient in hardware requirements being essentially modular. Starting from a single MCNP5 run permits a progressive improvement in the spatial detail of the material layers for the activation calculation and obtains separated source distributions for the isotopes contributing to the photon dose. (Author)

  12. The estimation of effective doses using measurement of several relevant physical parameters from radon exposures

    International Nuclear Information System (INIS)

    Ridzikova, A; Fronka, A.; Maly, B.; Moucka, L.

    2003-01-01

    In the present investigation, we will be study the dose relevant factors from continual monitoring in real homes into account getting more accurate estimation of 222 Rn the effective dose. The dose relevant parameters include the radon concentration, the equilibrium factor (f), the fraction (fp) of unattached radon decay products and real time occupancy people in home. The result of the measurement are the time courses of radon concentration that are based on estimation effective doses together with assessment of the real time occupancy people indoor. We found out by analysis that year effective dose is lower than effective dose estimated by ICRP recommendation from the integral measurement that included only average radon concentration. Our analysis of estimation effective doses using measurement of several physical parameters was made only in one case and for the better specification is important to measure in different real occupancy houses. (authors)

  13. Relationships Among Peripheral and Central Electrophysiological Measures of Spatial and Spectral Selectivity and Speech Perception in Cochlear Implant Users.

    Science.gov (United States)

    Scheperle, Rachel A; Abbas, Paul J

    2015-01-01

    The ability to perceive speech is related to the listener's ability to differentiate among frequencies (i.e., spectral resolution). Cochlear implant (CI) users exhibit variable speech-perception and spectral-resolution abilities, which can be attributed in part to the extent of electrode interactions at the periphery (i.e., spatial selectivity). However, electrophysiological measures of peripheral spatial selectivity have not been found to correlate with speech perception. The purpose of this study was to evaluate auditory processing at the periphery and cortex using both simple and spectrally complex stimuli to better understand the stages of neural processing underlying speech perception. The hypotheses were that (1) by more completely characterizing peripheral excitation patterns than in previous studies, significant correlations with measures of spectral selectivity and speech perception would be observed, (2) adding information about processing at a level central to the auditory nerve would account for additional variability in speech perception, and (3) responses elicited with spectrally complex stimuli would be more strongly correlated with speech perception than responses elicited with spectrally simple stimuli. Eleven adult CI users participated. Three experimental processor programs (MAPs) were created to vary the likelihood of electrode interactions within each participant. For each MAP, a subset of 7 of 22 intracochlear electrodes was activated: adjacent (MAP 1), every other (MAP 2), or every third (MAP 3). Peripheral spatial selectivity was assessed using the electrically evoked compound action potential (ECAP) to obtain channel-interaction functions for all activated electrodes (13 functions total). Central processing was assessed by eliciting the auditory change complex with both spatial (electrode pairs) and spectral (rippled noise) stimulus changes. Speech-perception measures included vowel discrimination and the Bamford-Kowal-Bench Speech

  14. Measuring dose from radiotherapy treatments in the vicinity of a cardiac pacemaker.

    Science.gov (United States)

    Peet, Samuel C; Wilks, Rachael; Kairn, Tanya; Crowe, Scott B

    2016-12-01

    This study investigated the dose absorbed by tissues surrounding artificial cardiac pacemakers during external beam radiotherapy procedures. The usefulness of out-of-field reference data, treatment planning systems, and skin dose measurements to estimate the dose in the vicinity of a pacemaker was also examined. Measurements were performed by installing a pacemaker onto an anthropomorphic phantom, and using radiochromic film and optically stimulated luminescence dosimeters to measure the dose in the vicinity of the device during the delivery of square fields and clinical treatment plans. It was found that the dose delivered in the vicinity of the cardiac device was unevenly distributed both laterally and anteroposteriorly. As the device was moved distally from the square field, the dose dropped exponentially, in line with out-of-field reference data in the literature. Treatment planning systems were found to substantially underestimate the dose for volumetric modulated arc therapy, helical tomotherapy, and 3D conformal treatments. The skin dose was observed to be either greater or lesser than the dose received at the depth of the device, depending on the treatment site, and so care should be if skin dose measurements are to be used to estimate the dose to a pacemaker. Square field reference data may be used as an upper estimate of absorbed dose per monitor unit in the vicinity of a cardiac device for complex treatments involving multiple gantry angles. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. Analysis and modeling of electronic portal imaging exit dose measurements

    International Nuclear Information System (INIS)

    Pistorius, S.; Yeboah, C.

    1995-01-01

    In spite of the technical advances in treatment planning and delivery in recent years, it is still unclear whether the recommended accuracy in dose delivery is being achieved. Electronic portal imaging devices, now in routine use in many centres, have the potential for quantitative dosimetry. As part of a project which aims to develop an expert-system based On-line Dosimetric Verification (ODV) system we have investigated and modelled the dose deposited in the detector of a video based portal imaging system. Monte Carlo techniques were used to simulate gamma and x-ray beams in homogeneous slab phantom geometries. Exit doses and energy spectra were scored as a function of (i) slab thickness, (ii) field size and (iii) the air gap between the exit surface and the detector. The results confirm that in order to accurately calculate the dose in the high atomic number Gd 2 O 2 S detector for a range of air gaps, field sizes and slab thicknesses both the magnitude of the primary and scattered components and their effective energy need to be considered. An analytic, convolution based model which attempts to do this is proposed. The results of the simulation and the ability of the model to represent these data will be presented and discussed. This model is used to show that, after training, a back-propagation feed-forward cascade correlation neural network has the ability to identify and recognise the cause of, significant dosimetric errors

  16. Is the dose equivalent index a quantity to be measured

    International Nuclear Information System (INIS)

    Wagner, S.R.

    1980-01-01

    The following modifying factors are briefly considered in relation to the ambiguities and limitations of the Dose Equivalent Index: 1) Variations with time or of the movement of the exposed person 2) Irradiation geometry 3) Effect of radiation energy 4) Instrument performance and calibration, and other operational quantities. (U.K.)

  17. Measurements of jet production and electromagnetic processes in ultra-peripheral Pb+Pb collisions with the ATLAS detector

    CERN Document Server

    Steinberg, Peter; The ATLAS collaboration

    2017-01-01

    Beams of relativistic heavy ions are accompanied by a large flux of equivalent photons, and photon- induced reactions are the dominant interaction mechanism in heavy-ion collisions when the colliding nuclei have transverse separation larger that the nuclear diameter. In these ultra- peripheral collisions (UPC) the photon can provide a clean probe of the partonic structure of the nucleus analogous with deep inelastic scattering. This talk presents measurements of jet production and electromagnetic processes in UPC in association with Pb+Pb collisions performed with the ATLAS detector. Dijet events are selected using requirements on rapidity gaps and forward neutron production to identify the photo-nuclear processes. The relatively clean environment of these events allows for measurements in a region of x and Q^2 where significant nuclear PDF modifications are expected to be present and not strongly constrained by previous measurements. High-mass dilepton pair continuum rates for Pb+Pb collisions are also prese...

  18. Immunocapture and microplate-based activity and quantity measurement of pyruvate dehydrogenase in human peripheral blood mononuclear cells.

    Science.gov (United States)

    Liu, Xiaowen; Pervez, Hira; Andersen, Lars W; Uber, Amy; Montissol, Sophia; Patel, Parth; Donnino, Michael W

    2015-01-01

    Pyruvate dehydrogenase (PDH) activity is altered in many human disorders. Current methods require tissue samples and yield inconsistent results. We describe a modified method for measuring PDH activity from isolated human peripheral blood mononuclear cells (PBMCs). RESULTS/METHODOLOGY: We found that PDH activity and quantity can be successfully measured in human PBMCs. Freeze-thaw cycles cannot efficiently disrupt the mitochondrial membrane. Processing time of up to 20 h does not affect PDH activity with proteinase inhibitor addition and a detergent concentration of 3.3% showed maximum yield. Sample protein concentration is correlated to PDH activity and quantity in human PBMCs from healthy subjects. Measuring PDH activity from PBMCs is a novel, easy and less invasive way to further understand the role of PDH in human disease.

  19. Immunocapture and microplate-based activity and quantity measurement of pyruvate dehydrogenase in human peripheral blood mononuclear cells

    Science.gov (United States)

    Liu, Xiaowen; Pervez, Hira; Andersen, Lars W; Uber, Amy; Montissol, Sophia; Patel, Parth; Donnino, Michael W

    2015-01-01

    Background Pyruvate dehydrogenase (PDH) activity is altered in many human disorders. Current methods require tissue samples and yield inconsistent results. We describe a modified method for measuring PDH activity from isolated human peripheral blood mononuclear cells (PBMCs). Results/Methodology We found that PDH activity and quantity can be successfully measured in human PBMCs. Freeze-thaw cycles cannot efficiently disrupt the mitochondrial membrane. Processing time of up to 20 h does not affect PDH activity with proteinase inhibitor addition and a detergent concentration of 3.3% showed maximum yield. Sample protein concentration is correlated to PDH activity and quantity in human PBMCs from healthy subjects. Conclusion Measuring PDH activity from PBMCs is a novel, easy and less invasive way to further understand the role of PDH in human disease. PMID:25826140

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

    International Nuclear Information System (INIS)

    El-Khatib, E.; Connors, S.

    1992-01-01

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

  1. Characterisation of a MOSFET-based detector for dose measurement under megavoltage electron beam radiotherapy

    Science.gov (United States)

    Jong, W. L.; Ung, N. M.; Tiong, A. H. L.; Rosenfeld, A. B.; Wong, J. H. D.

    2018-03-01

    The aim of this study is to investigate the fundamental dosimetric characteristics of the MOSkin detector for megavoltage electron beam dosimetry. The reproducibility, linearity, energy dependence, dose rate dependence, depth dose measurement, output factor measurement, and surface dose measurement under megavoltage electron beam were tested. The MOSkin detector showed excellent reproducibility (>98%) and linearity (R2= 1.00) up to 2000 cGy for 4-20 MeV electron beams. The MOSkin detector also showed minimal dose rate dependence (within ±3%) and energy dependence (within ±2%) over the clinical range of electron beams, except for an energy dependence at 4 MeV electron beam. An energy dependence correction factor of 1.075 is needed when the MOSkin detector is used for 4 MeV electron beam. The output factors measured by the MOSkin detector were within ±2% compared to those measured with the EBT3 film and CC13 chamber. The measured depth doses using the MOSkin detector agreed with those measured using the CC13 chamber, except at the build-up region due to the dose volume averaging effect of the CC13 chamber. For surface dose measurements, MOSkin measurements were in agreement within ±3% to those measured using EBT3 film. Measurements using the MOSkin detector were also compared to electron dose calculation algorithms namely the GGPB and eMC algorithms. Both algorithms were in agreement with measurements to within ±2% and ±4% for output factor (except for the 4 × 4 cm2 field size) and surface dose, respectively. With the uncertainties taken into account, the MOSkin detector was found to be a suitable detector for dose measurement under megavoltage electron beam. This has been demonstrated in the in vivo skin dose measurement on patients during electron boost to the breast tumour bed.

  2. Measurement of dosimetric parameters and dose verification in stereotactic radiosurgery (SRS)

    International Nuclear Information System (INIS)

    Reduan Abdullah; Nik Ruzman Nik Idris; Ahmad Lutfi Yusof; Mazurawati Mohamed

    2013-01-01

    Full-text: The purpose of this study was to measure the dosimetric parameters for small photon beams to be used as input data treatment planning computer system (TPS) and to verify dose calculated by TPS in Stereotactic Radiosurgery (SRS) procedure. The beam data required were Percentage Depth Dose (PDD), Off-axis Ratio (OAR), and Scatter Factor of Relative Output Factor. Small beams of 5 mm to 45 mm diameter circular cone collimators used in SRS were utilized for beam data measurements measured using pinpoint 3D ionization chamber (0.016 cc). For second part of this study, we reported the important quality assurance (QA) procedures before SRS treatment that influenced the dose delivery. These QA procedures consist of measurements on the accuracy in target localization and room laser alignment. The dose calculated to be delivered for treatment was verified using pinpoint 3D ionization chamber and TLD 100H. The mean deviation of measured dose using TLD 100H compared to calculated dose was 3.37 %. Beside that, pinpoint ionization 3D chamber give more accurate results of dose compared to TLD 100H. The measured dose using pinpoint 3D ionization chamber are good agreement with calculated dose by TPS with deviation of 2.17 %. The results are acceptable such as recommended by International Commission on Radiation Units and Measurements (ICRU) Report No. 50 (1993) that dose delivered to the target volume must be within ±5 % error. (author)

  3. In vivo measurement of radiation dose during radiotherapy in breast cancer patients using MOSFET dosimeter

    International Nuclear Information System (INIS)

    Wang Lili; Tu Yu; Zhou Juying; Lu Ye; Xu Xiaoting; Li Li; Qin Songbing

    2011-01-01

    Objective: The purpose of the study was to observe and analysis the actual dosage of patients with breast cancer using metal oxide semiconductor field effect transistor (MOSFET) detector. Methods: First, Phantom measurements were performed to investigate dose distribution in the area of the junction in a half-field matching method and the influence of factors related to the accelerator. In vivo dose measurements were performed for patients with breast cancer to investigate the skin dose and the junction of supraclavicular-axillary field and tangential field in 6 MV X-ray beams. Results: Phantom measurements showed that the relative deviation in the junction were within ±3%, and the dose distributions in the junction area depended on the matching field direction (x or y). In vivo measurement of tangential region for patients showed that, the maximum dose deviation between measurement and calculation was -30.39%,the minimum deviation was -18.85%, the average dose deviation was -24.76%. The dose deviation of tangential fields for patients with breast-conserving surgery was larger than that patients with radical surgery (t =2.40, P<0.05), while dose deviation of supraclavicular-axillary fields was not significantly different. The average values of 15 fraction in the junction area showed more stable than one individual measurement. Conclusions: It is important to real-time, in vivo measurement of radiation dose during radiotherapy in patients with breast cancer, and change treatment plan in time, to ensure the accuracy of target dose. (authors)

  4. Measurement of ambient dose equivalent H*(10) and directional dose equivalent H'(0.07) with pocket sized survey meters

    International Nuclear Information System (INIS)

    Iwatschenko, Michael

    2008-01-01

    Full text: In many parts of the world, predominantly in Europe, small sized survey meters based on Geiger-Mueller or proportional counters are widely used for dose rate and dose equivalent rate measurements, while in other regions, especially in the U.S., ionisation chambers are preferred for this task. This paper tries to shed some light on the likely reasons for these two diverging instrumental inclinations. Their respective strengths and weaknesses is analyzed in respect to energy response, dose rate measuring range, size, weight and susceptibility to environmental influences. Furthermore the response and limitations regarding the measurement of pulsed radiation (medical X-ray and CT-devices, accelerators, non-destructive testing) is discussed. A newly developed pocket size instrument based on a pan-cake Geiger-Mueller tube is used as an example to explain the capability and flexibility of modern survey meters. The RadEye B20 is a compact multi-purpose dose rate meter and contamination meter for alpha, beta, gamma and X-ray radiation. By virtue of carefully designed multi-layer gamma energy filters, H*(10) (deep dose) or H'(0,07) (shallow dose) measurements from 17 - 1300 keV can be performed. The instrument can even be worn in a belt holster, so that the impact to the mobility of the user is minimized. For emergency response purposes alpha and beta contamination can be discriminated using another optional filter; a simple sample changer adapter can extend the scope of application. Immediate and reproducible counter measurements, e.g. of smear tests can be performed locally. (author)

  5. Measurements of eye lens doses in interventional cardiology using OSL and electronic dosemeters

    International Nuclear Information System (INIS)

    Sanchez, R.M.; Vano, E.; Fernandez, J.M.; Ginjaume, M.; Duch, M.A.

    2014-01-01

    The purpose of this paper is to test the appropriateness of OSL and electronic dosemeters to estimate eye lens doses at interventional cardiology environment. Using TLD as reference detectors, personal dose equivalent was measured in phantoms and during clinical procedures. For phantom measurements, OSL dose values resulted in an average difference of 215 % vs. TLD. Tests carried out with other electronic dosemeters revealed differences up to ±20 % versus TLD. With dosemeters positioned outside the goggles and when TLD doses were >20 μSv, the average difference OSL vs. TLD was 29 %. Eye lens doses of almost 700 μSv per procedure were measured in two cases out of a sample of 33 measurements in individual clinical procedures, thus showing the risk of high exposure to the lenses of the eye when protection rules are not followed. The differences found between OSL and TLD are acceptable for the purpose and range of doses measured in the survey (authors)

  6. Radiation Dose Measurements in Routine X Ray Examinations

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  7. Multilayer detector for measuring absorbed dose in skin

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  8. Absorbed Dose Measurement in Gonads Menduring Abdominal and Pelvicradiotherapy

    OpenAIRE

    Sadegh Masoudi; Ali Asghar Yousefi; Somayeh Nourollahi; Fatemeh Noughani

    2013-01-01

    Two different testicular tissues have to be distinguished in regard to radiation damage: first the seminiferous tubules, corresponding to the sites of spermatogenesis, which are extremely radiosensitive. Second the testosterone secreting Leydig cells, which are considered to be less radiosensitive. This study aims to estimate testicular dose and the associated risks for infertility and hereditary effects from Abdominal and pelvic irradiation. Radiotherapy was simulated on a humanoid phantom u...

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

  11. Peripheral collisions in Ar induced reactions between 27 and 44 A.MeV: study of energy dissipation by measuring the correlated neutron multiplicities

    International Nuclear Information System (INIS)

    Guerreau, D.; Doubre, H.; Galin, J.; Pouthas, J.; Jahnke, U.; Jiang, D.X.; Lott, B.; Jacquet, D.

    1988-01-01

    A 4 π detector measuring the neutron multiplicities has been used to investigate the energy dissipation during peripheral collisions in Ar induced reactions around the Fermi Energy. Besides the persistance of direct transfer reactions for the most peripheral collisions, there are strong evidences for the occurrence of quite large energy dissipation, a clear signature for the one body friction to still play a major role at these intermediate energies

  12. A simplified approach for exit dose in vivo measurements in radiotherapy and its clinical application

    International Nuclear Information System (INIS)

    Banjade, D.P.; Shukri, A.; Tajuddin, A.A.; Shrestha, S.L.; Bhat, M.

    2002-01-01

    This is a study using LiF:Mg;Ti thermoluminescent dosimeter (TLD) rods in phantoms to investigate the effect of lack of backscatter on exit dose. Comparing the measured dose with anticipated dose calculated using tissue maximum ratio (TMR) or percentage depth dose (PDD) gives rise to a correction factor. This correction factor may be applied to in-vivo dosimetry results to derive true dose to a point within the patient. Measurements in a specially designed humanoid breast phantom as well as patients undergoing radiotherapy treatment were also been done. TLDs with reproducibility of within ±3% (1 SD) are irradiated in a series of measurements for 6 and 10 MV photon beams from a medical linear accelerator. The measured exit doses for the different phantom thickness for 6 MV beams are found to be lowered by 10.9 to 14.0% compared to the dose derived from theoretical estimation (normalized dose at d max ). The same measurements for 10 MV beams are lowered by 9.0 to 13.5%. The variations of measured exit dose for different field sizes are found to be within 2.5%. The exit doses with added backscatter material from 2 mm up to 15 cm, shows gradual increase and the saturated values agreed within 1.5% with the expected results for both beams. The measured exit doses in humanoid breast phantom as well as in the clinical trial on patients undergoing radiotherapy also agreed with the predicted results based on phantom measurements. The authors' viewpoint is that this technique provides sufficient information to design exit surface bolus to restore build down effect in cases where part of the exit surface is being considered as a target volume. It indicates that the technique could be translated for in vivo dose measurements, which may be a conspicuous step of quality assurance in clinical practice. Copyright (2002) Australasian College of Physical Scientists and Engineers in Medicine

  13. Efficient and reliable 3D dose quality assurance for IMRT by combining independent dose calculations with measurements

    NARCIS (Netherlands)

    Visser, R.; Wauben, D. J. L.; de Groot, M.; Godart, J.; Langendijk, J. A.; van t Veld, Aart A.; Korevaar, E. W.

    Purpose: Advanced radiotherapy treatments require appropriate quality assurance (QA) to verify 3D dose distributions. Moreover, increase in patient numbers demand efficient QA-methods. In this study, a time efficient method that combines model-based QA and measurement-based QA was developed; i.e.,

  14. Measurements of eye lens doses in interventional radiology and cardiology: Final results of the ORAMED project

    International Nuclear Information System (INIS)

    Vanhavere, F.; Carinou, E.; Domienik, J.; Donadille, L.; Ginjaume, M.; Gualdrini, G.; Koukorava, C.; Krim, S.; Nikodemova, D.; Ruiz-Lopez, N.; Sans-Merce, M.; Struelens, L.

    2011-01-01

    Within the ORAMED project (Optimization of Radiation Protection of Medical Staff) a coordinated measurement program for occupationally exposed medical staff was performed in different hospitals in Europe ( (www.oramed-fp7.eu)). The main objective was to obtain a set of standardized data on extremity and eye lens doses for staff involved in interventional radiology and cardiology and to optimize radiation protection. Special attention was given to the measurement of the doses to the eye lenses. In this paper an overview will be given of the measured eye lens doses and the main influence factors for these doses. The measured eye lens doses are extrapolated to annual doses. The extrapolations showed that monitoring of the eye lens should be performed on routine basis.

  15. Measurement of californium-252 gamma photons depth dose distribution in tissue equivalent material. Vol. 4

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, M A; El-Fiki, M A; Eissa, H M; Abdel-Hafez, A; Naguib, S H [National Institute of Standards, Cairo (Egypt)

    1996-03-01

    Phantom of tissue equivalent material with and without bone was used measuring depth dose distribution of gamma-rays from californium-252 source. The source was positioned at center of perspex walled phantom. Depth dose measurements were recorded for X, Y and Z planes at different distances from source. TLD 700 was used for measuring the dose distribution. Results indicate that implantation of bone in tissue equivalent medium cause changes in the gamma depth dose distribution which varies according to variation in bone geometry. 9 figs.

  16. Prototype development or multi-cavity ion chamber for depth dose measurement

    International Nuclear Information System (INIS)

    Nayak, M.K.; Sahu, T.K.; Haridas, G.; Bandyopadhyay, Tapas; Tripathi, R.M.; Nandedkar, R.V.

    2016-01-01

    In high energy electron accelerators, when the electrons interact with vacuum chamber or surrounding structural material, Bremsstrahlung x-rays are produced. It is having a broad spectrum extending up to the electron energies. Dose measured as a function of depth due to electromagnetic cascade will give rise to depth dose curve. To measure the online depth dose profile in an absorber medium, when high energy electron or Bremsstrahlung is incident, a prototype Multi-Cavity Ion Chamber (MCIC) detector is developed. The paper describes the design and development of the MCIC for measurement of depth dose profile

  17. Measurement of dose enhancement close to high atomic number media using optical fibre thermoluminescence dosimeters

    International Nuclear Information System (INIS)

    Alalawi, Amani I.; Hugtenburg, R.P.; Abdul Rahman, A.T.; Barry, M.A.; Nisbet, A.; Alzimami, Khalid S.; Bradley, D.A.

    2014-01-01

    Present interest concerns development of a system to measure photoelectron-enhanced dose close to a tissue interface using analogue gold-coated doped silica-fibre thermoluminescence detectors and an X-ray set operating at 250 kVp. Study is made of the dose enhancement factor for various thicknesses of gold; measurements at a total gold thickness of 160 nm (accounting for incident and exiting photons) produces a mean measured dose enhancement factor of 1.33±0.01 To verify results, simulations of the experimental setup have been performed. - Highlights: • Dose enhancement • Thermoluminescence dosimeter • Monte Carlo simulation

  18. Exact comparison of dose rate measurements and calculation of TN12/2 packages

    International Nuclear Information System (INIS)

    Taniuchi, H.; Matsuda, F.

    1998-01-01

    Both of dose rate measurements of TN 12/2 package and calculations by Monte Carlo code MORSE in SCALE code system and MCNP were performed to evaluate the difference between the measurement and the calculation and finding out the cause of the difference. The calculated gamma-ray dose rates agreed well with measured ones, but calculated neutron dose rates overestimated more than a factor of 1.7. When considering the cause of the difference and applying the modification into the neutron calculation, the calculated neutron dose rates become to agree well, and the factor decreased to around 1.3. (authors)

  19. Kinetic energy measurement of hydrogen in LHD peripheral plasma with a multi-wavelength-range fine-resolution spectrometer

    International Nuclear Information System (INIS)

    Fujii, Keisuke; Mizushiri, Keisuke; Nishioka, Tomomi; Shikama, Taiichi; Iwamae, Atsushi; Goto, Motoshi; Morita, Shigeru; Hasuo, Masahiro

    2010-01-01

    We have simultaneously measured high resolution emission spectra of the hydrogen atomic Balmer-α, -β, -γ lines and molecular Fulcher-α band for a LHD peripheral plasma generated under a central magnetic field strength of 0.4 T. It is found that the velocity distributions of excited atoms calculated from the Balmer-α, -β, and -γ line shapes show similar profiles to each other. The translational kinetic energy corresponding to the average velocity is about 13 eV, which is about 300 times larger than the rotational energy of hydrogen molecules estimated from the line intensities in the Fulcher-α band. The velocity distributions differ from Maxwellian and have a high velocity tail over 1x10 5 m/s. A correlation between the high velocity tail and the electron temperature and density is seen and suggesting the excited atoms having such high velocities to be generated by the charge exchange collisions from high velocity protons in the peripheral region.

  20. Dose determination with nitro blue tetrazolium containing radiochromic dye films by measuring absorbed and reflected light

    DEFF Research Database (Denmark)

    Kovács, A.; Baranyai, M.; Wojnárovits, L.

    2000-01-01

    determination in a wide dose range both by absorbance and reflectance measurements. The concept of measuring reflected light from dose labels has been discussed earlier and emerged recently due to the requirement of introducing semiquantitative label dose indicators for quarantine control. The usefulness...... of the method was studied using the newly developed radiochromic dye films as well as already existing ones. (C) 2000 Elsevier Science Ltd. All rights reserved....

  1. Absolute dose measurement Gafchromic R EBT2 movies. Case Study of Kaposis sarcoma

    International Nuclear Information System (INIS)

    Pereira, L.; Moral, F. del; Meilan, E.; Azevedo Gomes, J. C. de; Tejeiro Garcia, A. G.; Andrade Alvarez, B.; Vazquez, J.; Nieto, I.; Medal, D.; Lopez Medina, A.; Francisco, S.; Salgado, M.; Munoz, V.

    2011-01-01

    Because of its high spatial resolution, low energy dependence and good response over a wide energy range, EBT2 Gafchromic films are widely used in many applications in radiotherapy for measuring relative dose. Despite being the most common use can be used to measure absolute dose. This text is an example of using films as EBT2 for in vivo absolute dose in a Kaposis sarcoma.

  2. Review of techniques and detectors used in instruments for field measurement of beta doses and dose rates

    International Nuclear Information System (INIS)

    Jones, A.R.

    1983-01-01

    Generally, field measurements are required to assess the hazard from #betta#-rays before personnel are allowed to occupy a working space or perform a task. Occasionally, the measurements are required for an assessment after a #betta#-ray exposure is suspected to have occurred. Until recently the dose or dose rate have been the quantities of interest but there is now felt to be a need to characterize the energies and directions of the #betta#-rays as well. The purpose of #betta#-dosimetry is the assessment of hazard to superficial tissues (within approx. 10 mm of the surface) and that these tissues may also be exposed simultaneously to other ionizing radiations. The #betta#-dosimetry technique must take account of this. With these uses of field instruments in mind the following detectors, and associated techniques will be discussed in terms of the measurement principles, advantages and limitations: thin-walled ion chambers (sometimes in combination with thick-walled ones or with covers thick enough to prevent penetration of #betta#-particles); thin scintillators, nearly tissue equivalent, to provide a detector analogous to skin; scintillators, thick enough to absorb all the energy of the #betta#-particles (circuitry is required to count pulses according to size to permit calculation of dose or dose rate); silicon diodes with thin detection layers operated as photocurrent generators; silicon diodes, reversed biassed, with pulses counted according to size; and simple pulse counters (e.g., GM counters or silicon diodes with thin windows)

  3. Dose measurements in intraoral radiography using thermoluminescent dosimeters

    Science.gov (United States)

    Azorín, C.; Azorín, J.; Aguirre, F.; Rivera, T.

    2015-01-01

    The use of X-ray in medicine demands to expose the patient and the professional to the lowest radiation doses available in agreement with ALARA philosophy. The reference level for intraoral dental radiography is 7 mGy and, in Mexico, a number of examinations of this type are performed annually. It is considered that approximately 25% of all the X-rays examinations carried out in our country correspond to intraoral radiographies. In other hand, most of the intraoral X-ray equipment correspond to conventional radiological systems using film, which are developed as much manual as automatically. In this work the results of determining the doses received by the patients in intraoral radiological examinations made with different radiological systems using LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters are presented. In some conventional radiological systems using film, when films are developed manual or automatically, incident kerma up to 10.61 ± 0.74 mGv were determined. These values exceed that reference level suggested by the IAEA and in the Mexican standards for intraoral examinations.

  4. Dose measurements in intraoral radiography using thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Azorín, C; Rivera, T; Azorín, J; Aguirre, F

    2015-01-01

    The use of X-ray in medicine demands to expose the patient and the professional to the lowest radiation doses available in agreement with ALARA philosophy. The reference level for intraoral dental radiography is 7 mGy and, in Mexico, a number of examinations of this type are performed annually. It is considered that approximately 25% of all the X-rays examinations carried out in our country correspond to intraoral radiographies. In other hand, most of the intraoral X-ray equipment correspond to conventional radiological systems using film, which are developed as much manual as automatically. In this work the results of determining the doses received by the patients in intraoral radiological examinations made with different radiological systems using LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters are presented. In some conventional radiological systems using film, when films are developed manual or automatically, incident kerma up to 10.61 ± 0.74 mGv were determined. These values exceed that reference level suggested by the IAEA and in the Mexican standards for intraoral examinations

  5. Measurement of Patient Dose from Computed Tomography Using Physical Anthropomorphic Phantom

    International Nuclear Information System (INIS)

    Jang, Ki Won; Lee, Jae Ki; Kim, Jong Kyung

    2005-01-01

    The computed tomography (CT) provides a high quality in images of human body but contributes relatively high patient dose compared with the conventional X-ray examination. Furthermore, the frequency of CT examination has been increasing in Korea for the last decade owing to the national health insurance benefits. Increasing concerns about high patient dose from CT have stimulated a great deal of researches on dose assessment, which many of these are based on the Monte Carlo simulation. But in this study, absorbed doses and effective dose of patient undergoing CT examination were determined experimentally using anthropomorphic physical phantom and the measured results are compared with those from Monte Carlo calculation

  6. The Use Of Optical Properties Of Cr-39 In Alpha Particle Equivalent Dose Measurements

    International Nuclear Information System (INIS)

    Shnishin, K.A.

    2007-01-01

    In this work, optical properties of alpha irradiated Cr-39 were measured as a function of optical photon wavelength from 200-1100 nm. Optical energy gap and optical absorption at finite wavelength was also calculated and correlated to alpha fluence and dose equivalent. Alpha doses were calculated from the corresponding irradiation fluence and specific energy loss using TRIM computer program. It was found that, the optical absorption of unattached Cr-39 was varied with alpha fluence and corresponding equivalent doses. Also the optical energy gab was varied with fluence and dose equivalent of alpha particles. This work introduces a reasonably simple method for the Rn dose equivalent calculation by Cr-39 track

  7. SU-E-T-196: Comparative Analysis of Surface Dose Measurements Using MOSFET Detector and Dose Predicted by Eclipse - AAA with Varying Dose Calculation Grid Size

    Energy Technology Data Exchange (ETDEWEB)

    Badkul, R; Nejaiman, S; Pokhrel, D; Jiang, H; Kumar, P [University of Kansas Medical Center, Kansas City, KS (United States)

    2015-06-15

    Purpose: Skin dose can be the limiting factor and fairly common reason to interrupt the treatment, especially for treating head-and-neck with Intensity-modulated-radiation-therapy(IMRT) or Volumetrically-modulated - arc-therapy (VMAT) and breast with tangentially-directed-beams. Aim of this study was to investigate accuracy of near-surface dose predicted by Eclipse treatment-planning-system (TPS) using Anisotropic-Analytic Algorithm (AAA)with varying calculation grid-size and comparing with metal-oxide-semiconductor-field-effect-transistors(MOSFETs)measurements for a range of clinical-conditions (open-field,dynamic-wedge, physical-wedge, IMRT,VMAT). Methods: QUASAR™-Body-Phantom was used in this study with oval curved-surfaces to mimic breast, chest wall and head-and-neck sites.A CT-scan was obtained with five radio-opaque markers(ROM) placed on the surface of phantom to mimic the range of incident angles for measurements and dose prediction using 2mm slice thickness.At each ROM, small structure(1mmx2mm) were contoured to obtain mean-doses from TPS.Calculations were performed for open-field,dynamic-wedge,physical-wedge,IMRT and VMAT using Varian-21EX,6&15MV photons using twogrid-sizes:2.5mm and 1mm.Calibration checks were performed to ensure that MOSFETs response were within ±5%.Surface-doses were measured at five locations and compared with TPS calculations. Results: For 6MV: 2.5mm grid-size,mean calculated doses(MCD)were higher by 10%(±7.6),10%(±7.6),20%(±8.5),40%(±7.5),30%(±6.9) and for 1mm grid-size MCD were higher by 0%(±5.7),0%(±4.2),0%(±5.5),1.2%(±5.0),1.1% (±7.8) for open-field,dynamic-wedge,physical-wedge,IMRT,VMAT respectively.For 15MV: 2.5mm grid-size,MCD were higher by 30%(±14.6),30%(±14.6),30%(±14.0),40%(±11.0),30%(±3.5)and for 1mm grid-size MCD were higher by 10% (±10.6), 10%(±9.8),10%(±8.0),30%(±7.8),10%(±3.8) for open-field, dynamic-wedge, physical-wedge, IMRT, VMAT respectively.For 6MV, 86% and 56% of all measured values

  8. Comparison of dose measurements in water versus in air for therapy

    International Nuclear Information System (INIS)

    Nasukha

    1987-01-01

    Comparison of dose measurements in water versus in air for therapy. Dose measurements in water and in the air had been done by teletherapy unit Co-60 Picker Model V 4m/60 with Farmer dosimeter. The result of inverse square law, TAR, PDD, and PSF compared to BJR No. 17 produced a difference of more than 4,65% with SSD 80 cm. Doses in water calculated from the result of dose measurement in air using BJR tables given, was compared with direct dose measurement in water. Values of 0,9850 to 1,0302 were obtained if using inverse square law, PDD and PSF formula. Using inverse square law and TAR, values of 0,9474 to 1,0197 were obtained for 4 depths and 5 field sizes. Measurements done in 5 cm depth and 10 cm x 10 cm field size using both methods, were still good. (author). 7 figs, 8 refs

  9. Measurement of spinal or peripheral bone mass to estimate early postmenopausal bone loss

    International Nuclear Information System (INIS)

    Riis, B.J.; Christiansen, C.

    1988-01-01

    This report presents data from 153 healthy, early postmenopausal women who were randomly allocated to two years of treatment with estrogen or placebo. Bone mineral content in the forearms was measured by single-photon absorptiometry, and bone mineral density of the lumbar spine and total-body bone mineral by dual-photon absorptiometry, before and after one and two years of treatment. At the end of the two years, there were highly significant differences of 6 to 7 percent between the estrogen and the placebo groups at all sites measured. The range of the changes of the spine measurement was twice that of the forearm and total-body measurements. It is concluded that measurement of the forearm by single-photon absorptiometry is superior to measurement of the spine by dual-photon absorptiometry both in clinical studies and in the individual patient for detecting estrogen-dependent bone loss and its treatment by estrogen replacement

  10. Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takemi; Tonoike, Kotaro; Miyoshi, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The authors participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the authors derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose by the evaluation formula to the measured value by the alanine dosimeter was 0.94 and the formula agreed within 6%. From examination of this TRACY, we can conclude that the value reported to OECD/NEA has equivalent accuracy. (author)

  11. Estimation of the fetal dose by dose measurement during an irradiation of a parotid tumor; Estimation de la dose foetale par mesure de dose lors d'une irradiation d'une tumeur de la parotide

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, V.; Graff-Cailleaud, P.; Peiffert, D. [Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Noel, A. [Institut National Polytechnique de Lorraine, CRAN CNRS UMR-7039, 54 - Vandoeuvre-les-Nancy (France)

    2006-11-15

    The irradiation of a five months pregnant patient has been made for a right parotid attack. In conformation with the legislative texts relative to radiation protection ( publication 84 of the ICRP) an estimation of the dose received for the fetus has been led by dose measurement on phantom. With the dose limit ( 100 mGy) recommended in the publication 84 of the ICRP neither modification of the treatment nor abortion was necessary. (N.C.)

  12. Measurement and assessment of doses from external radiations required for revised radiation protection regulations

    International Nuclear Information System (INIS)

    Tsujimura, Norio; Kojima, Noboru; Hayashi, Naomi

    2001-01-01

    Radiation protection regulations based on the 1990 recommendations of ICRP have been revised and will take effect from Apr., 2001. The major changes concerning on the measurement and assessment of doses from external radiations are as follows. (1) Personal dose equivalent and ambient dose equivalent stated in ICRP Publication 74 are introduced as quantities to be measured with personal dosimeters and survey instruments, respectively. (2) For multiple dosimetry for workers, the compartment weighting factors used for a realistic assessment of effective dose are markedly changed. In advance of the introduction of the new radiation protection regulations, the impacts on workplace and personal monitoring for external radiations by these revisions were investigated. The following results were obtained. (1) A new ambient dose equivalent to neutrons is higher with a factor of 1.2 than the old one for moderated fission neutron spectra. Therefore, neutron dose equivalent monitors for workplace monitoring at MOX fuel for facilities should be recalibrated for measurement of the new ambient dose equivalent. (2) Annual effective doses of workers were estimated by applying new calibration factors to readings of personal dosimeters, worn by workers. Differences between effective doses and effective dose equivalents are small for workers engaged in the fabrication process of MOX fuel. (author)

  13. Measurement and assessment of doses from external radiations required for revised radiation protection regulations

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Norio; Kojima, Noboru; Hayashi, Naomi [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2001-06-01

    Radiation protection regulations based on the 1990 recommendations of ICRP have been revised and will take effect from Apr., 2001. The major changes concerning on the measurement and assessment of doses from external radiations are as follows. (1) Personal dose equivalent and ambient dose equivalent stated in ICRP Publication 74 are introduced as quantities to be measured with personal dosimeters and survey instruments, respectively. (2) For multiple dosimetry for workers, the compartment weighting factors used for a realistic assessment of effective dose are markedly changed. In advance of the introduction of the new radiation protection regulations, the impacts on workplace and personal monitoring for external radiations by these revisions were investigated. The following results were obtained. (1) A new ambient dose equivalent to neutrons is higher with a factor of 1.2 than the old one for moderated fission neutron spectra. Therefore, neutron dose equivalent monitors for workplace monitoring at MOX fuel for facilities should be recalibrated for measurement of the new ambient dose equivalent. (2) Annual effective doses of workers were estimated by applying new calibration factors to readings of personal dosimeters, worn by workers. Differences between effective doses and effective dose equivalents are small for workers engaged in the fabrication process of MOX fuel. (author)

  14. Measurement of depth-dose distributions by means of the LiF-fluoroplastic thermoluminescent detectors

    International Nuclear Information System (INIS)

    Shaks, A.I.; Uryaev, I.A.; Trifonov, V.A.; Reshetnikova, L.V.

    1977-01-01

    Depth-dose distributions have been studied by means of thin-layer thermoluminescent detectors LiF-fluoroplast (8 mg/cm 2 ). Dosimetric characteristics of the detectors are described. They are: tissue-equivalence, dependence of sensitivity on the dose, dose rate and angle of incidence of radiation, and time-dependent storage, of the total light absorbed. Comparison of the results obtained with the measurements taken with an extrapolation chamber has demonstrated the possibility of measuring the depth-dose distributions by means of LiF-fluoroplast detectors

  15. Guideline values for skin decontamination measures based on nuclidspecific dose equivalent rate factors

    International Nuclear Information System (INIS)

    Pfob, H.; Heinemann, G.

    1992-01-01

    Corresponding dose equivalent rate factors for various radionuclides are now available for determining the skin dose caused by skin contamination. These dose equivalent rate factors take into account all contributions from the types of radiation emitted. Any limits for skin decontamination measures are nowhere contained or determined yet. However, radiological protection does in practice require at least guideline values in order to prevent unsuitable or detrimental measures that can be noticed quite often. New calculations of dose equivalent rate factors for the skin now make the recommendation of guideline values possible. (author)

  16. An overview of measuring and modelling dose and risk from ionising radiation for medical exposures

    International Nuclear Information System (INIS)

    Tootell, Andrew; Szczepura, Katy; Hogg, Peter

    2014-01-01

    Purpose: This paper gives an overview of the methods that are used to calculate dose and risk from exposure to ionizing radiation as a support to other papers in this special issue. Background: The optimization of radiation dose is a legal requirement in medical exposures. This review paper aims to provide the reader with knowledge of dose by providing definitions and concepts of absorbed, effective and equivalent dose. Criticisms of the use of effective dose to infer the risk of an exposure to an individual will be discussed and an alternative approach considering the lifetime risks of cancer incidence will be considered. Prior to any dose or risk calculation, data concerning the dose absorbed by the patient needs to be collected. This paper will describe and discuss the main concepts and methods that can be utilised by a researcher in dose assessments. Concepts behind figures generated by imaging equipment such as dose-area-product, computed tomography dose index, dose length product and their use in effective dose calculations will be discussed. Processes, advantages and disadvantages in the simulation of exposures using the Monte Carlo method and direct measurement using digital dosimeters or thermoluminescent dosimeters will be considered. Beyond this special issue, it is proposed that this paper could serve as a teaching or CPD tool for personnel working or studying medical imaging

  17. FBX dosimetry for point dose measurements in head and neck cancer patients

    International Nuclear Information System (INIS)

    Balraj, A.; Thakur, P.K.; Bhatnagar, S.; Vidyasagar, P.B.; Nirhali, Amit; Semwal, M.K.

    2007-01-01

    FBX dosimeter is mainly based on the determination of the radiation dose from the chemical changes produced in an irradiated medium, which can be measured by Spectrophotometry or Colorimetry, for which adequate FBX solution of 2 ml required for measuring the optical density (OD). To measure the point dose using 2 ml solution may lead to error in the measured dose since the solution may occupy 2 cc volume of the point measured. In head and neck carcinoma patients, the treatment area involves curvatures. Fixing 2 ml vial at the body surface is difficult and leads to give wrong readings. In this study we have measured the entrance and exit dose by filling 0.5 ml solution in a flexible catheter and placed at a point in the patient body surface during the radiation treatment. The solution was diluted adding 1.5 ml distilled water to measure the OD in the colorimeter

  18. Number of distal limb and brachial pressure measurements required when diagnosing peripheral arterial disease by laser Doppler flowmetry

    International Nuclear Information System (INIS)

    Høyer, C; Biurrun Manresa, J A; Petersen, L J

    2013-01-01

    We examine the reliability of single and repeated blood pressure measurements at ankle, toe, and arm levels for the diagnosis of peripheral arterial disease (PAD) by laser Doppler flowmetry. Segmental pressures were measured in 200 patients with known or suspected PAD. Segmental indices were calculated using (1) one measurement [M-1], two measurements [M-2], or by a predefined reproducibility criterion (RC) as well as (2) by using one brachial blood-pressure (BBP-one) or correspondent to each segmental pressure (BBP-all) as reference. The agreement in diagnosis of PAD by Cohen's Kappa was κ = 0.930 when comparing RC to M-1, and κ = 0.977 when comparing RC to M-2. The same comparison showed excellent relative reliability for segmental indices (all intra-class correlation coefficients (ICC) ≥ 0.980). Diagnostic classification agreement for BBP-all versus BBP-one were κ = 0.831 for RC, κ = 0.804 for M-1, and κ = 0.847 for M-2. The relative reliability analysis showed excellent correlation in segmental indices (all ICC ≥ 0.957). The study shows minimal difference in segmental indices and diagnostic classification when comparing calculations based on the listed strategies. However, the study indicated that it is important to measure BBPs correspondent to each segmental pressure. (paper)

  19. The software program Peridose to calculate the fetal dose or dose to other critical structures outside the target area in radiation therapy

    International Nuclear Information System (INIS)

    Giessen, P.H. van der

    2001-01-01

    An accurate estimate of the dose outside the target area is of utmost importance when pregnant patients have to undergo radiotherapy, something that occurs in every radiotherapy department once in a while. Such peripheral doses (PD) are also of interest for late effects risk estimations for doses to specific organs as well as estimations of dose to pacemakers. A software program, Peridose, is described to allow easy calculation of this peripheral dose. The calculation is based on data from many publications on peripheral dose measurements, including those by the author. Clinical measurements have shown that by using data averaged over many measurements and different machine types PDs can be estimated with an accuracy of ± 60% (2 standard deviations). The program allows easy and fairly accurate estimates of peripheral doses in patients. Further development to overcome some of the constraints and limitations is desirable. The use of average data is to be preferred if general applicability is to be maintained. (author)

  20. Isotopic diagnosis of peripheral thrombosis

    International Nuclear Information System (INIS)

    Cornu, Pierre; Scalet, Michel

    1975-01-01

    Radio-isotope diagnosis of peripheral venous thrombosis, using tracer doses of iodine-labelled fibrinogen, provides an important contribution to the solution of the worrying problem of pulmonary embolism due to latent phlebitis. This elegant and precise technique permits early diagnosis of venous thrombosis of the lower limbs at a subclinical stage. It has permitted determination of the frequency, both after surgery and after myocardial infarction, and above all, it provides an objective criterion for assessment of the efficacy of prophylactic measures proposed [fr

  1. Determining clinical photon beam spectra from measured depth dose with the Cimmino algorithm

    International Nuclear Information System (INIS)

    Bloch, P.; Altschuler, M.D.; Bjaerngard, B.E.; Kassaee, A.; McDonough, J.

    2000-01-01

    A method to determine the spectrum of a clinical photon beam from measured depth-dose data is described. At shallow depths, where the range of Compton-generated electrons increases rapidly with photon energy, the depth dose provides the information to discriminate the spectral contributions. To minimize the influence of contaminating electrons, small (6x6cm2 ) fields were used. The measured depth dose is represented as a linear combination of basis functions, namely the depth doses of monoenergetic photon beams derived by Monte Carlo simulations. The weights of the basis functions were obtained with the Cimmino feasibility algorithm, which examines in each iteration the discrepancy between predicted and measured depth dose. For 6 and 15 MV photon beams of a clinical accelerator, the depth dose obtained from the derived spectral weights was within about 1% of the measured depth dose at all depths. Because the problem is ill conditioned, solutions for the spectrum can fluctuate with energy. Physically realistic smooth spectra for these photon beams appeared when a small margin (about ±1%) was attributed to the measured depth dose. The maximum energy of both derived spectra agreed with the measured energy of the electrons striking the target to within 1 MeV. The use of a feasibility method on minimally relaxed constraints provides realistic spectra quickly and interactively. (author)

  2. Composite depth dose measurement for total skin electron (TSE) treatments using radiochromic film

    International Nuclear Information System (INIS)

    Gamble, Lisa M; Farrell, Thomas J; Jones, Glenn W; Hayward, Joseph E

    2003-01-01

    Total skin electron (TSE) radiotherapy is routinely used to treat cutaneous T-cell lymphomas and can be implemented using a modified Stanford technique. In our centre, the composite depth dose for this technique is achieved by a combination of two patient positions per day over a three-day cycle, and two gantry angles per patient position. Due to patient morphology, underdosed regions typically occur and have historically been measured using multiple thermoluminescent dosimeters (TLDs). We show that radiochromic film can be used as a two-dimensional relative dosimeter to measure the percent depth dose in TSE radiotherapy. Composite depth dose curves were measured in a cylindrical, polystyrene phantom and compared with TLD data. Both multiple films (1 film per day) and a single film were used in order to reproduce a realistic clinical scenario. First, three individual films were used to measure the depth dose, one per treatment day, and then compared with TLD data; this comparison showed a reasonable agreement. Secondly, a single film was used to measure the dose delivered over three daily treatments and then compared with TLD data; this comparison showed good agreement throughout the depth dose, which includes doses well below 1 Gy. It will be shown that one piece of radiochromic film is sufficient to measure the composite percent depth dose for a TSE beam, hence making radiochromic film a suitable candidate for monitoring underdosed patient regions

  3. SU-E-T-481: In Vivo and Post Mortem Animal Irradiation: Measured Vs. Calculated Doses

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, P [Univ New Mexico Radiology Dept., Albuquerque, NM (United States); Heintz, B [Texas Oncology, PA, Southlake, TX (United States); Sandoval, D [University of New Mexico, Albuquerque, NM (United States); Weber, W; Melo, D; Guilmette, R [Lovelace Respiratory Research Institute, Albuquerque, NM (United States)

    2015-06-15

    Purpose: Computerized radiation therapy treatment planning is performed on almost all patients today. However it is seldom used for laboratory irradiations. The first objective is to assess whether modern radiation therapy treatment planning (RTP) systems accurately predict the subject dose by comparing in vivo and decedent dose measurements to calculated doses. The other objective is determine the importance of using a RTP system for laboratory irradiations. Methods: 5 MOSFET radiation dosimeters were placed enterically in each subject (2 sedated Rhesus Macaques) to measure the absorbed dose at 5 levels (carina, lung, heart, liver and rectum) during whole body irradiation. The subjects were treated with large opposed lateral fields and extended distances to cover the entire subject using a Varian 600C linac. CT simulation was performed ante-mortem (AM) and post-mortem (PM). To compare AM and PM doses, calculation points were placed at the location of each dosimeter in the treatment plan. The measured results were compared to the results using Varian Eclipse and Prowess Panther RTP systems. Results: The Varian and Prowess treatment planning system agreed to within in +1.5% for both subjects. However there were significant differences between the measured and calculated doses. For both animals the calculated central axis dose was higher than prescribed by 3–5%. This was caused in part by inaccurate measurement of animal thickness at the time of irradiation. For one subject the doses ranged from 4% to 7% high and the other subject the doses ranged 7% to 14% high when compared to the RTP doses. Conclusions: Our results suggest that using proper CT RTP system can more accurately deliver the prescribed dose to laboratory subjects. It also shows that there is significant dose variation in such subjects when inhomogeneities are not considered in the planning process.

  4. Measures of chronic kidney disease and risk of incident peripheral artery disease: a collaborative meta-analysis of individual participant data.

    Science.gov (United States)

    Matsushita, Kunihiro; Ballew, Shoshana H; Coresh, Josef; Arima, Hisatomi; Ärnlöv, Johan; Cirillo, Massimo; Ebert, Natalie; Hiramoto, Jade S; Kimm, Heejin; Shlipak, Michael G; Visseren, Frank L J; Gansevoort, Ron T; Kovesdy, Csaba P; Shalev, Varda; Woodward, Mark; Kronenberg, Florian

    2017-09-01

    Some evidence suggests that chronic kidney disease is a risk factor for lower-extremity peripheral artery disease. We aimed to quantify the independent and joint associations of two measures of chronic kidney disease (estimated glomerular filtration rate [eGFR] and albuminuria) with the incidence of peripheral artery disease. In this collaborative meta-analysis of international cohorts included in the Chronic Kidney Disease Prognosis Consortium (baseline measurements obtained between 1972 and 2014) with baseline measurements of eGFR and albuminuria, at least 1000 participants (this criterion not applied to cohorts exclusively enrolling patients with chronic kidney disease), and at least 50 peripheral artery disease events, we analysed adult participants without peripheral artery disease at baseline at the individual patient level with Cox proportional hazards models to quantify associations of creatinine-based eGFR, urine albumin-to-creatinine ratio (ACR), and dipstick proteinuria with the incidence of peripheral artery disease (including hospitalisation with a diagnosis of peripheral artery disease, intermittent claudication, leg revascularisation, and leg amputation). We assessed discrimination improvement through c-statistics. We analysed 817 084 individuals without a history of peripheral artery disease at baseline from 21 cohorts. 18 261 cases of peripheral artery disease were recorded during follow-up across cohorts (median follow-up was 7·4 years [IQR 5·7-8·9], range 2·0-15·8 years across cohorts). Both chronic kidney disease measures were independently associated with the incidence of peripheral artery disease. Compared with an eGFR of 95 mL/min per 1·73 m 2 , adjusted hazard ratios (HRs) for incident study-specific peripheral artery disease was 1·22 (95% CI 1·14-1·30) at an eGFR of 45 mL/min per 1·73 m 2 and 2·06 (1·70-2·48) at an eGFR of 15 mL/min per 1·73 m 2 . Compared with an ACR of 5 mg/g, the adjusted HR for incident study

  5. Measurement of radiation dose to ovaries from CT of the head and trunk

    Energy Technology Data Exchange (ETDEWEB)

    Al-Habdhan, M.A.M.; Kinsara, A.R. [King Abdul Aziz Univ., Nuclear Engineering Dept., Jeddah (Saudi Arabia)

    2001-07-01

    With the rise in concern about doses received by patients over recent years, there has been a growing requirement for information on typical doses and the range of dose received during Computerized Tomography (CT). This study was performed for the assessment of radiation dose to the ovaries from various CT protocols for head and trunk imaging. Thermo luminescent dosimeters (TLD) were used for the dosimetry measurement in an anthropomorphic Rando Alderson phantom. The wanted (obligatory) and unwanted (non-useful) radiation doses delivered to the ovaries during CT examinations of head, facial bone, orbits, abdomen, chest, pelvis, neck, nasopharynx, cervical spine, lumber spine and sacroiliac joint were assessed. The results are compared with the corresponding values published in the literature. A comparison of the received dose from CT examinations and general radiography examinations by the ovaries was made. It is found that relatively high doses of unwanted radiation are delivered with computerized tomography. (author)

  6. Using an electronic portal imaging device for exit dose measurements in radiotherapy

    International Nuclear Information System (INIS)

    Ganowicz, M.; Wozniak, B.; Bekman, A.; Maniakowski, Z.

    2003-01-01

    To present a method of determining the exit dose with the use of an electronic portal imaging device (EPID). The device used was the Portal Vision LC250 (Varian). The EPID signals on the central beam axis have been related to the exit dose. The exit dose measurements were performed with the ionisation chamber in the slab phantom at the distance of dose maximum from the exit surface of the phantom. EPID reading was investigated as a function of field size, phantom thickness and source-detector distance. The relation between dose rate and the EPID reading is described with empirical functions applicable to the obtained data. The exit dose is calculated from the EPID reading as a product of the calibration factor and appropriate correction factors. The determination of the exit dose rate from the EPID signal requires the knowledge of many parameters and earlier determination of essential characteristics. (author)

  7. Systematic measurements of whole-body imaging dose distributions in image-guided radiation therapy

    International Nuclear Information System (INIS)

    Hälg, Roger A.; Besserer, Jürgen; Schneider, Uwe

    2012-01-01

    Purpose: The full benefit of the increased precision of contemporary treatment techniques can only be exploited if the accuracy of the patient positioning is guaranteed. Therefore, more and more imaging modalities are used in the process of the patient setup in clinical routine of radiation therapy. The improved accuracy in patient positioning, however, results in additional dose contributions to the integral patient dose. To quantify this, absorbed dose measurements from typical imaging procedures involved in an image-guided radiation therapy treatment were measured in an anthropomorphic phantom for a complete course of treatment. The experimental setup, including the measurement positions in the phantom, was exactly the same as in a preceding study of radiotherapy stray dose measurements. This allows a direct combination of imaging dose distributions with the therapy dose distribution. Methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The dose distributions from imaging devices used with treatment machines from the manufacturers Accuray, Elekta, Siemens, and Varian and from computed tomography scanners from GE Healthcare were determined and the resulting effective dose was calculated. The list of investigated imaging techniques consisted of cone beam computed tomography (kilo- and megavoltage), megavoltage fan beam computed tomography, kilo- and megavoltage planar imaging, planning computed tomography with and without gating methods and planar scout views. Results: A conventional 3D planning CT resulted in an effective dose additional to the treatment stray dose of less than 1 mSv outside of the treated volume, whereas a 4D planning CT resulted in a 10 times larger dose. For a daily setup of the patient with two planar kilovoltage images or with a fan beam CT at the TomoTherapy unit, an additional effective dose outside of the treated volume of less than 0.4 mSv and 1

  8. Surface dose measurements in and out of field. Implications for breast radiotherapy with megavoltage photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Lonski, Peta; Kron, Tomas [Peter MacCallum Cancer Centre, Melbourne (Australia); RMIT Univ., Melbourne (Australia); Ramachandran, Prabhakar; Franich, Rick [Peter MacCallum Cancer Centre, Melbourne (Australia)

    2017-07-01

    This study examines the difference in surface dose between flat and flattening filter free (FFF) photon beams in the context of breast radiotherapy. The surface dose was measured for 6 MV, 6 MV FFF, 10 MV, 10 MV FFF and 18 MV photon beams using a thin window ionisation chamber for various field sizes. Profiles were acquired to ascertain the change in surface dose off-axis. Out-of-field measurements were included in a clinically representative half beam block tangential breast field. In the field centres of FFF beams the surface dose was found to be increased for small fields and decreased for large fields compared to flat beams. For FFF beams, surface dose was found to decrease off-axis and resulted in lower surface dose out-of-field compared to flat beams.

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

    Energy Technology Data Exchange (ETDEWEB)

    Klein, J [Bezirkskrankenhaus Brandenburg (German Democratic Republic)

    1981-03-01

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

  10. Measurements of surgeons' exposure to ionizing radiation dose during intraoperative use of C-arm fluoroscopy.

    Science.gov (United States)

    Lee, Kisung; Lee, Kyoung Min; Park, Moon Seok; Lee, Boram; Kwon, Dae Gyu; Chung, Chin Youb

    2012-06-15

    Measurement of radiation dose from C-arm fluoroscopy during a simulated intraoperative use in spine surgery. OBJECTIVE.: To investigate scatter radiation doses to specific organs of surgeons during intraoperative use of C-arm fluoroscopy in spine surgery and to provide practical intraoperative guidelines. There have been studies that reported the radiation dose of C-arm fluoroscopy in various procedures. However, radiation doses to surgeons' specific organs during spine surgery have not been sufficiently examined, and the practical intraoperative radioprotective guidelines have not been suggested. Scatter radiation dose (air kerma rate) was measured during the use of a C-arm on an anthropomorphic chest phantom on an operating table. Then, a whole body anthropomorphic phantom was located besides the chest phantom to simulate a surgeon, and scatter radiation doses to specific organs (eye, thyroid, breast, and gonads) and direct radiation dose to the surgeon's hand were measured using 4 C-arm configurations (standard, inverted, translateral, and tube translateral). The effects of rotating the surgeon's head away from the patient and of a thyroid shield were also evaluated. Scatter radiation doses decreased as distance from the patient increased during C-arm fluoroscopy use. The standard and translateral C-arm configurations caused lower scatter doses to sensitive organs than inverted and tube translateral configurations. Scatter doses were highest for breast and lowest for gonads. The use of a thyroid shield and rotating the surgeon's head away from the patient reduced scatter radiation dose to the surgeon's thyroid and eyes. The direct radiation dose was at least 20 times greater than scatter doses to sensitive organs. The following factors could reduce radiation exposure during intraoperative use of C-arm; (1) distance from the patient, (2) C-arm configuration, (3) radioprotective equipments, (4) rotating the surgeons' eyes away from the patient, and (5) avoiding

  11. Computed tomography dose and variability of airway dimension measurements: how low can we go?

    International Nuclear Information System (INIS)

    Jong, Pim A. de; Long, Frederick R.; Nakano, Yasutaka

    2006-01-01

    Quantitative CT shows promise as an outcome measure for cystic fibrosis (CF) lung disease in infancy, but must be accomplished at a dose as low as reasonably achievable. To determine the feasibility of ultra-low-dose CT for quantitative measurements of airway dimensions. Two juvenile pigs were anesthetized and their lungs scanned at 25 cm H 2 O face-mask pressure in apnoea using beam currents of 5, 10, 20, 40 and 100 mAs. The lumen diameters and wall thicknesses of matched airways (n=22) at each dose were measured by two observers using validated software. Measurement variability at each dose was compared to that at 100 mAs (reference dose) for large and small airways (lumen diameter <2.5 mm). Lowering CT dose (mAs) affected measurement variability for lumen diameter of small and large airways (P<0.001) and for wall thickness of small (P<0.001), but not large (P=0.63), airways. To obtain the same measurement variability at 5 mAs as at 100 mAs, four to six small airways or one to three large airways have to be measured and averaged. Quantitative airway measurements are feasible on images obtained at as low as 5 mAs, but more airways need to be measured to compensate for greater measurement variability. (orig.)

  12. Developing a single-aliquot protocol for measuring equivalent dose in biogenic carbonates

    International Nuclear Information System (INIS)

    Stirling, R.J.; Duller, G.A.T.; Roberts, H.M.

    2012-01-01

    Exploiting biogenic carbonates as thermoluminescence dosimeters requires an understanding of trap kinetics and an appropriate sequence with which to measure equivalent dose. The trap kinetics of two high temperature peaks (peaks II and III) from calcitic snail opercula have been investigated resulting in the calculation of lifetimes of 7.4 × 10 7 and 1.4 × 10 11 years for the two peaks respectively. Two measurement sequences, based upon changes in the application and measurement of a test dose, have been applied to peaks II and III, and though both methods were equally successful in dose recovery and production of a dose response curve some differences were observed. Primarily, the use of method 1 lead to dose dependant sensitivity change implying competition effects occurring during irradiation; method 2 did not experience this phenomenon. As a consequence method 2 was chosen as the most appropriate protocol for single-aliquot dating of this material. When assessing the TL behaviour of the two peaks, peak II performed poorly in dose recovery experiments recovering a dose 60–100% larger than that applied. Disproportionate growth of peak II in response to a beta dose applied prior to measurement, compared to growth following regeneration doses indicated that peak II was not suitable for use in single-aliquot protocols. However, dose recovery results for peak III were all within errors of unity of the given dose, and peak III was therefore chosen as the most appropriate peak for TL dosimetry in these single-aliquot procedures. The lifetime of charge in peak III is sufficient to date over many millions of years, and furthermore using the chosen method 2 the dose response curve has a D 0 of 3,250 ± 163 Gy allowing dating to over 3 million years.

  13. Alanine-EPR dosimetry system for high industrial as well radiotherapeutic dose measurement

    International Nuclear Information System (INIS)

    Dobrovodsky, J.; Bukovjan, J.

    2005-01-01

    Slovak Institute of Metrology is developing new metrology standard for high doses, based on the alanine-EPR as a reference dosimetry system. A Bruker e-scan EPR analyser developed specifically for alanine dosimetry has improved stability of EPR measurement, especially at lower dose range. The standard e-scan system provides sensitivity below 1 Gray. After further improvement of the system and lowering of dose determination expanded uncertainty down below 1 %, its utilisation for radiotherapy field is expected (authors)

  14. Fiber optical dose rate measurement based on the luminescence of beryllium oxide

    Directory of Open Access Journals (Sweden)

    Teichmann Tobias

    2018-01-01

    Full Text Available This work presents a fiber optical dose rate measurement system based on the radioluminescence and optically stimulated luminescence of beryllium oxide. The system consists of a small, radiation sensitive probe which is coupled to a light detection unit with a long and flexible light guide. Exposing the beryllium oxide probe to ionizing radiation results in the emission of light with an intensity which is proportional to the dose rate. Additionally, optically stimulated luminescence can be used to obtain dose and dose rate information during irradiation or retrospectively. The system is capable of real time dose rate measurements in fields of high dose rates and dose rate gradients and in complex, narrow geometries. This enables the application for radiation protection measurements as well as for quality control in radiotherapy. One inherent drawback of fiber optical dosimetry systems is the generation of Cherenkov radiation and luminescence in the light guide itself when it is exposed to ionizing radiation. This so called “stem” effect leads to an additional signal which introduces a deviation in the dose rate measurement and reduces the spatial resolution of the system, hence it has to be removed. The current system uses temporal discrimination of the effect for radioluminescence measurements in pulsed radiation fields and modulated optically stimulated luminescence for continuous irradiation conditions. This work gives an overview of the major results and discusses new-found obstacles of the applied methods of stem discrimination.

  15. Dose management as a measurable criteria into the quality control programme of an imaging diagnostic clinic

    International Nuclear Information System (INIS)

    Kirova, G.; Georgiev, E.; Zasheva, C.; Georgiev, S.

    2014-01-01

    In the Radiology Department of Tokuda Hospital Sofia, a strong control over the radiation dose for all patients was accepted with the implementation of the Dose Watch software. The system allows bad practices to be discovered and improves the efficiency and quality of the CT procedures performed in the department. The article will briefly demonstrate the main steps, which have been done, and the results, which have been achieved. The purpose is to identify the challenges, the available tools, and the opportunities for improving the patients' dose in the CT sector of a general Radiology Department. Collected data was based on the information concerning the radiation dose absorbed by individual patients undergoing MDCT examinations in a general radiology department with an overall annual rate of around 7000 MDCT examinations. All of them were carried out using a single 64row MDCT system. The hospital logbook was used to identify the number of CT examinations and dose levels associated with some typical diagnostic procedures in order to make an analysis. The information was taken form the PACS and Dose Watch software and was analyzed. The article draws some measures towards improving the organization and reducing the dose, keeping the quality of the performed exams. Thanks to the supportive software for dose tracking, analyzing and reporting, some problems have been solved and some reasonable measures have been implemented into the daily practice. (authors) Key words: RADIATION DOSE. MDCT. DOSE REDUCTION. REFERRAL GUIDELINES.CTDI. DLP

  16. Photon and neutron doses of the personnel using moisture and density measurement devices

    Energy Technology Data Exchange (ETDEWEB)

    Carinou, E.; Papadomarkaki, E.; Tritakis, P.; Hourdakis, C.I.; Kamenopoulou, V. [Greek Atomic Energy Commission, Agia Paraskevi, Attiki, 60092 (Greece)

    2006-07-01

    The objective of this study is to present the evolution of the photon doses received by the workers who use mobile devices for measuring the moisture and the density in various materials and to estimate the neutron doses. The workers employed in more than 30 construction companies in Greece were 76 in 2004. The devices used for that purpose incorporate a {sup 137}Cs source for density measurements and an {sup 241}Am-Be source for moisture measurements of soil, asphalt or concrete. Photon and neutron measurements were performed occasionally during the on site inspections. The results of the measurements showed that the photon and neutron dose rates were not negligible. The workers were monitored for photon radiation using film badges (Kodak Type 2, Holder NRPB type) till the year 2000 and then TLD badges issued by the Greek Atomic Energy Commission (GAEC), on a monthly basis. Since the neutron dose rates measured by a rem-meter were not so high, no neutron dosemeters were issued for them. Their personal dose equivalent data for photons are kept in the National Dose Registry Information System (N.D.R.I.S.) in G.A.E.C. and were used for statistical analysis for the period from 1997 till 2004. As far as the neutrons are concerned, a Monte Carlo code was used to simulate the measuring devices and the working positions in order to calculate the neutron individual doses. (authors)

  17. Photon and neutron doses of the personnel using moisture and density measurement devices

    International Nuclear Information System (INIS)

    Carinou, E.; Papadomarkaki, E.; Tritakis, P.; Hourdakis, C.I.; Kamenopoulou, V.

    2006-01-01

    The objective of this study is to present the evolution of the photon doses received by the workers who use mobile devices for measuring the moisture and the density in various materials and to estimate the neutron doses. The workers employed in more than 30 construction companies in Greece were 76 in 2004. The devices used for that purpose incorporate a 137 Cs source for density measurements and an 241 Am-Be source for moisture measurements of soil, asphalt or concrete. Photon and neutron measurements were performed occasionally during the on site inspections. The results of the measurements showed that the photon and neutron dose rates were not negligible. The workers were monitored for photon radiation using film badges (Kodak Type 2, Holder NRPB type) till the year 2000 and then TLD badges issued by the Greek Atomic Energy Commission (GAEC), on a monthly basis. Since the neutron dose rates measured by a rem-meter were not so high, no neutron dosemeters were issued for them. Their personal dose equivalent data for photons are kept in the National Dose Registry Information System (N.D.R.I.S.) in G.A.E.C. and were used for statistical analysis for the period from 1997 till 2004. As far as the neutrons are concerned, a Monte Carlo code was used to simulate the measuring devices and the working positions in order to calculate the neutron individual doses. (authors)

  18. Experiment for dose measurement during beam killing at Indus-1 synchrotron radiation source

    International Nuclear Information System (INIS)

    Nayak, M.K.; Dev, Vipin; Haridas, G.; Thakkar, K.K.; Sarkar, P.K.; Sharma, D.N.

    2006-01-01

    Experimental measurement of radiation dose likely to be received by an occupational worker in the experimental hall of Indus-1 during accidental beam killing was carried out. Various accidental beam-killing scenarios were experimentally simulated for the measurement. The measurement was carried out using direct reading dosimeters. Result shows that in the event of accidental beam killing, dose likely to be received by an occupational worker outside the shield is negligible. (author)

  19. Measurement of exposure dose rate by TLD in 60Co garden

    International Nuclear Information System (INIS)

    Fan Chengfang; Li Pinfang; Wu Maoliang; Zhao Quan

    1987-01-01

    The use of TLD method to measure exposure dose rate in 60 Co garden is described. As compared with chemical dosimetry, the relative deviation of measurement would not exceed 10%. The good repeatability has been proved by comparing the measurements of different times and distances with correction of decay law and 1/1 2 law. Besides, the distribution of exposure dose rate was influenced by scattering of the living plants

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  1. Can the green laser doppler measure skin-nutritive perfusion in patients with peripheral vascular disease?

    NARCIS (Netherlands)

    Ubbink, D. T.; Tulevski, I. I.; Jacobs, M. J.

    2000-01-01

    The recently developed green laser (GL; wavelength 543 nm) is thought to measure perfusion derived from a more superficial skin layer than does the standard near-infrared laser (RL; wavelength 780 nm). These lasers were used to investigate the disturbances in the different layers of skin perfusion

  2. Classification of peripheral occlusive arterial diseases based on symptoms, signs and distal blood pressure measurements

    DEFF Research Database (Denmark)

    Tønnesen, K H; Noer, Ivan; Paaske, William

    1980-01-01

    Systolic blood pressures at toe and ankle were measured in 459 consecutive patients with occlusive arterial disease. Fifty-eight per cent had intermittent claudication with arterial disease of all degrees of severity. Seventeen per cent complained of rest pain having toe systolic pressures below 30...

  3. Device for measuring the dose rate of pulsed neutrons

    International Nuclear Information System (INIS)

    Klett, A.

    2009-01-01

    The author presents a new apparatus, developed in collaboration by Berthold Technologies and the German company DESY, allowing neutron pulsed fields to be measured. It is based on the activation by high energy neutrons of carbon 12 present in the sensor materials, and on the decay of short life radionuclides produced by this activation. The detection principle and system are briefly presented

  4. Real-time measurement and monitoring of absorbed dose for electron beams

    Science.gov (United States)

    Korenev, Sergey; Korenev, Ivan; Rumega, Stanislav; Grossman, Leon

    2004-09-01

    The real-time method and system for measurement and monitoring of absorbed dose for industrial and research electron accelerators is considered in the report. The system was created on the basis of beam parameters method. The main concept of this method consists in the measurement of dissipated kinetic energy of electrons in the irradiated product, determination of number of electrons and mass of irradiated product in the same cell by following calculation of absorbed dose in the cell. The manual and automation systems for dose measurements are described. The systems are acceptable for all types of electron accelerators.

  5. Real-time measurement and monitoring of absorbed dose for electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, Sergey E-mail: sergey_korenev@steris.com; Korenev, Ivan; Rumega, Stanislav; Grossman, Leon

    2004-10-01

    The real-time method and system for measurement and monitoring of absorbed dose for industrial and research electron accelerators is considered in the report. The system was created on the basis of beam parameters method. The main concept of this method consists in the measurement of dissipated kinetic energy of electrons in the irradiated product, determination of number of electrons and mass of irradiated product in the same cell by following calculation of absorbed dose in the cell. The manual and automation systems for dose measurements are described. The systems are acceptable for all types of electron accelerators.

  6. Real-time measurement and monitoring of absorbed dose for electron beams

    International Nuclear Information System (INIS)

    Korenev, Sergey; Korenev, Ivan; Rumega, Stanislav; Grossman, Leon

    2004-01-01

    The real-time method and system for measurement and monitoring of absorbed dose for industrial and research electron accelerators is considered in the report. The system was created on the basis of beam parameters method. The main concept of this method consists in the measurement of dissipated kinetic energy of electrons in the irradiated product, determination of number of electrons and mass of irradiated product in the same cell by following calculation of absorbed dose in the cell. The manual and automation systems for dose measurements are described. The systems are acceptable for all types of electron accelerators

  7. Efficient and reliable 3D dose quality assurance for IMRT by combining independent dose calculations with measurements

    International Nuclear Information System (INIS)

    Visser, R.; Wauben, D. J. L.; Godart, J.; Langendijk, J. A.; Veld, A. A. van't; Korevaar, E. W.; Groot, M. de

    2013-01-01

    Purpose: Advanced radiotherapy treatments require appropriate quality assurance (QA) to verify 3D dose distributions. Moreover, increase in patient numbers demand efficient QA-methods. In this study, a time efficient method that combines model-based QA and measurement-based QA was developed; i.e., the hybrid-QA. The purpose of this study was to determine the reliability of the model-based QA and to evaluate time efficiency of the hybrid-QA method. Methods: Accuracy of the model-based QA was determined by comparison of COMPASS calculated dose with Monte Carlo calculations for heterogeneous media. In total, 330 intensity modulated radiation therapy (IMRT) treatment plans were evaluated based on the mean gamma index (GI) with criteria of 3%/3mm and classification of PASS (GI ≤ 0.4), EVAL (0.4 0.6), and FAIL (GI ≥ 0.6). Agreement between model-based QA and measurement-based QA was determined for 48 treatment plans, and linac stability was verified for 15 months. Finally, time efficiency improvement of the hybrid-QA was quantified for four representative treatment plans. Results: COMPASS calculated dose was in agreement with Monte Carlo dose, with a maximum error of 3.2% in heterogeneous media with high density (2.4 g/cm 3 ). Hybrid-QA results for IMRT treatment plans showed an excellent PASS rate of 98% for all cases. Model-based QA was in agreement with measurement-based QA, as shown by a minimal difference in GI of 0.03 ± 0.08. Linac stability was high with an average GI of 0.28 ± 0.04. The hybrid-QA method resulted in a time efficiency improvement of 15 min per treatment plan QA compared to measurement-based QA. Conclusions: The hybrid-QA method is adequate for efficient and accurate 3D dose verification. It combines time efficiency of model-based QA with reliability of measurement-based QA and is suitable for implementation within any radiotherapy department.

  8. Neutron and gamma dose and spectra measurements on the Little Boy replica

    International Nuclear Information System (INIS)

    Hoots, S.; Wadsworth, D.

    1984-01-01

    The radiation-measurement team of the Weapons Engineering Division at Lawrence Livermore National Laboratory (LLNL) measured neutron and gamma dose and spectra on the Little Boy replica at Los Alamos National Laboratory (LANL) in April 1983. This assembly is a replica of the gun-type atomic bomb exploded over Hiroshima in 1945. These measurements support the National Academy of Sciences Program to reassess the radiation doses due to atomic bomb explosions in Japan. Specifically, the following types of information were important: neutron spectra as a function of geometry, gamma to neutron dose ratios out to 1.5 km, and neutron attenuation in the atmosphere. We measured neutron and gamma dose/fission from close-in to a kilometer out, and neutron and gamma spectra at 90 and 30 0 close-in. This paper describes these measurements and the results. 12 references, 13 figures, 5 tables

  9. Comparison of measured and calculated doses for narrow MLC defined fields

    International Nuclear Information System (INIS)

    Lydon, J.; Rozenfeld, A.; Lerch, M.

    2002-01-01

    Full text: The introduction of Intensity Modulated Radiotherapy (IMRT) has led to the use of narrow fields in the delivery of radiation doses to patients. Such fields are not well characterized by calculation methods commonly used in radiotherapy treatment planning systems. The accuracy of the dose calculation algorithm must therefore be investigated prior to clinical use. This study looked at symmetrical and asymmetrical 0.1 to 3cm wide fields delivered with a Varian CL2100C 6MV photon beam. Measured doses were compared to doses calculated using Pinnacle, the ADAC radiotherapy treatment planning system. Two high resolution methods of measuring dose were used. A MOSFET detector in a water phantom and radiographic film in a solid water phantom with spatial resolutions of 10 and 89μm respectively. Dose calculations were performed using the collapsed cone convolution algorithm in Pinnacle with a 0.1cm dose calculation grid in the MLC direction. The effect of Pinnacle not taking into account the rounded leaf ends was simulated by offsetting the leaves by 0.1cm in the dose calculation. Agreement between measurement and calculation is good for fields of 1cm and wider. However, fields of less than 1cm width can show a significant difference between measurement and calculation

  10. Polymer gel dosimetry for synchrotron stereotactic radiotherapy and iodine dose-enhancement measurements

    International Nuclear Information System (INIS)

    Boudou, C; Tropres, I; Rousseau, J; Lamalle, L; Adam, J F; Esteve, F; Elleaume, H

    2007-01-01

    Synchrotron stereotactic radiotherapy (SSR) is a radiotherapy technique that makes use of the interactions of monochromatic low energy x-rays with high atomic number (Z) elements. An important dose-enhancement can be obtained if the target volume has been loaded with a sufficient amount of a high-Z element, such as iodine. In this study, we compare experimental dose measurements, obtained with normoxic polymer gel (nPAG), with Monte Carlo computations. Gels were irradiated within an anthropomorphic head phantom and were read out by magnetic resonance imaging. The dose-enhancement due to the presence of iodine in the gel (iodine concentration: 5 and 10 mg ml -1 ) was measured at two radiation energies (35 and 80 keV) and was compared to the calculated factors. nPAG dosimetry was shown to be efficient for measuring the sharp dose gradients produced by SSR. The agreement between 3D gel dosimetry and calculated dose distributions was found to be within 4% of the dose difference criterion and a distance to agreement of 2.1 mm for 80% of the voxels. Polymer gel doped with iodine exhibited higher sensitivity, in good agreement with the calculated iodine-dose enhancement. We demonstrate in this preliminary study that iodine-doped nPAG could be used for measuring in situ dose distributions for iodine-enhanced SSR treatment

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

    International Nuclear Information System (INIS)

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

    1983-06-01

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

  12. A measurement-based generalized source model for Monte Carlo dose simulations of CT scans.

    Science.gov (United States)

    Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

    2017-03-07

    The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients' CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

  13. A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

    Science.gov (United States)

    Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

    2017-03-01

    The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

  14. German measurements of the population dose around Chernobyl

    International Nuclear Information System (INIS)

    Hille, R.

    1997-01-01

    The reports on the consequences of the reactor accident at Chernobyl in late April 1986 have been extremely contradictory as yet. In the post-Soviet republics affected by the accident there was a general lack of reliable information concerning the levels of radioactive contamination of the environment and of foodstuffs. Where data were given, they were insufficiently supported and explained. Not least, these circumstances led to considerable disquiet and concern amongst the public even at a great distance from the site of the accident. In order to assist in informing those affected and above all to determine their actual radiation exposure, the Federal Republic of Germany performed a measuring campaign in the three post-Soviet republics between Moscow and Kiev in the years 1991-1993. For this purpose, the Federal Ministry of the Environment made available funds of about DM 12 million. Starting in 1991 a total of 22 vehicles math 27 measuring assemblies and more than 150 staff, recruited on a voluntary basis from various institutions in the Federal Republic of Germany, were engaged in the first measuring campaign lasting from mid-May to early October 1991. In the following two years the programme was slightly reduced. Great store was set by the comprehensive information of the population. In addition to general information through the media two leaflets were distributed to all visitors to explain the radiological situation. Each person undergoing measurements or bringing food samples received a form with the results and a short explanation in Russian. This was favourably accepted by the public

  15. Measurement and estimation of maximum skin dose to the patient for different interventional procedures

    International Nuclear Information System (INIS)

    Cheng Yuxi; Liu Lantao; Wei Kedao; Yu Peng; Yan Shulin; Li Tianchang

    2005-01-01

    Objective: To determine the dose distribution and maximum skin dose to the patient for four interventional procedures: coronary angiography (CA), hepatic angiography (HA), radiofrequency ablation (RF) and cerebral angiography (CAG), and to estimate the definitive effect of radiation on skin. Methods: Skin dose was measured using LiF: Mg, Cu, P TLD chips. A total of 9 measuring points were chosen on the back of the patient with two TLDs placed at each point, for CA, HA and RF interventional procedures, whereas two TLDs were placed on one point each at the postero-anterior (PA) and lateral side (LAT) respectively, during the CAG procedure. Results: The results revealed that the maximum skin dose to the patient was 1683.91 mGy for the HA procedure with a mean value of 607.29 mGy. The maximum skin dose at the PA point was 959.3 mGy for the CAG with a mean value of 418.79 mGy; While the maximum and the mean doses at the LAT point were 704 mGy and 191.52 mGy, respectively. For the RF procedure the maximum dose was 853.82 mGy and the mean was 219.67 mGy. For the CA procedure the maximum dose was 456.1 mGy and the mean was 227.63 mGy. Conclusion: All the measured dose values in this study are estimated ones which could not provide the accurate maximum value because it is difficult to measure using a great deal of TLDs. On the other hand, the small area of skin exposed to high dose could be missed as the distribution of the dose is successive. (authors)

  16. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A.; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M.; Dhote, Dipak S.; Deshpande, Deepak D.

    2009-01-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  17. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy.

    Science.gov (United States)

    Kinhikar, Rajesh A; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M; Dhote, Dipak S; Deshpande, Deepak D

    2009-09-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  18. Peripheral plasma measurement during SMBI in Heliotron J using fast cameras

    International Nuclear Information System (INIS)

    Nishino, N.; Mizuuchi, T.; Takeuchi, M.; Mukai, K.; Takabatake, Y.; Nagasaki, K.; Kobayashi, S.; Okada, H.; Ohshima, S.; Yamamoto, S.; Minami, T.; Hanatani, K.; Konoshima, S.; Nakamura, Y.; Sano, F.

    2011-01-01

    Since fueling technique is very important for maintaining fusion plasma, supersonic molecular beam injection (SMBI) was studied using mainly fast cameras, Hα measurement, Langmuir/magnetic probes, and electron density/diamagnetic measurement in Heliotron J. Using a fast camera with a tangential view a very bright stripe along the magnetic field line was observed during SMBI. Time-dependent FFT analysis of data from each pixel showed that the low frequency waves rotated around the magnetic field line in a left-handed sense at the initial stage of SMBI. After a few milliseconds they propagated towards the SMBI region along the magnetic field line, and their phase velocities were almost the same. Experimental evidence is consistent with the interpretation as the ion acoustic wave, and the peak frequency of these waves was the same as that of the power spectra of the magnetic probe signals. It suggests the slow magnetoacoustic wave may convert into the ion acoustic wave due to collisions with neutrals.

  19. Pediatric patient and staff dose measurements in barium meal fluoroscopic procedures

    Science.gov (United States)

    Filipov, D.; Schelin, H. R.; Denyak, V.; Paschuk, S. A.; Porto, L. E.; Ledesma, J. A.; Nascimento, E. X.; Legnani, A.; Andrade, M. E. A.; Khoury, H. J.

    2015-11-01

    This study investigates patient and staff dose measurements in pediatric barium meal series fluoroscopic procedures. It aims to analyze radiographic techniques, measure the air kerma-area product (PKA), and estimate the staff's eye lens, thyroid and hands equivalent doses. The procedures of 41 patients were studied, and PKA values were calculated using LiF:Mg,Ti thermoluminescent dosimeters (TLDs) positioned at the center of the patient's upper chest. Furthermore, LiF:Mg,Cu,P TLDs were used to estimate the equivalent doses. The results showed a discrepancy in the radiographic techniques when compared to the European Commission recommendations. Half of the results of the analyzed literature presented lower PKA and dose reference level values than the present study. The staff's equivalent doses strongly depends on the distance from the beam. A 55-cm distance can be considered satisfactory. However, a distance decrease of ~20% leads to, at least, two times higher equivalent doses. For eye lenses this dose is significantly greater than the annual limit set by the International Commission on Radiological Protection. In addition, the occupational doses were found to be much higher than in the literature. Changing the used radiographic techniques to the ones recommended by the European Communities, it is expected to achieve lower PKA values ​​and occupational doses.

  20. Analysis of liquid medication dose errors made by patients and caregivers using alternative measuring devices.

    Science.gov (United States)

    Ryu, Gyeong Suk; Lee, Yu Jeung

    2012-01-01

    Patients use several types of devices to measure liquid medication. Using a criterion ranging from a 10% to 40% variation from a target 5 mL for a teaspoon dose, previous studies have found that a considerable proportion of patients or caregivers make errors when dosing liquid medication with measuring devices. To determine the rate and magnitude of liquid medication dose errors that occur with patient/caregiver use of various measuring devices in a community pharmacy. Liquid medication measurements by patients or caregivers were observed in a convenience sample of community pharmacy patrons in Korea during a 2-week period in March 2011. Participants included all patients or caregivers (N = 300) who came to the pharmacy to buy over-the-counter liquid medication or to have a liquid medication prescription filled during the study period. The participants were instructed by an investigator who was also a pharmacist to select their preferred measuring devices from 6 alternatives (etched-calibration dosing cup, printed-calibration dosing cup, dosing spoon, syringe, dispensing bottle, or spoon with a bottle adapter) and measure a 5 mL dose of Coben (chlorpheniramine maleate/phenylephrine HCl, Daewoo Pharm. Co., Ltd) syrup using the device of their choice. The investigator used an ISOLAB graduated cylinder (Germany, blue grad, 10 mL) to measure the amount of syrup dispensed by the study participants. Participant characteristics were recorded including gender, age, education level, and relationship to the person for whom the medication was intended. Of the 300 participants, 257 (85.7%) were female; 286 (95.3%) had at least a high school education; and 282 (94.0%) were caregivers (parent or grandparent) for the patient. The mean (SD) measured dose was 4.949 (0.378) mL for the 300 participants. In analysis of variance of the 6 measuring devices, the greatest difference from the 5 mL target was a mean 5.552 mL for 17 subjects who used the regular (etched) dosing cup and 4

  1. Some measurements of doses to patients from dental X-rays

    International Nuclear Information System (INIS)

    Woehni, T.

    1976-01-01

    Some measurements of doses to patients from conventional dental radiography and orthopantomography are presented. Doses to the red bone marrow are calculated. The bone marrow doses from two different exposures, Maxilla incisor and Molar bite-wing, were calculated to be 0.4 and 1.0 mrad respectively. The average dose to red bone marrow from a full-mouth examination (10 exposures) was 0.7 mrad/exposure. An orthopantomographic examination involved 2 mrad to the bone marrow. The greatest doses from an orthopantomographic examination were found around the lateral rotational axis, namely 700 mrad. The dose distributions from the two different cone lengths did not differ as much as expected, mainly due to scattered radiation. (Auth.)

  2. Some measurements of doses to patients from dental X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Woehni, T [Statens Institutt for Straalehygiene, Oslo (Norway)

    1976-11-01

    Some measurements of doses to patients from conventional dental radiography and orthopantomography are presented. Doses to the red bone marrow are calculated. The bone marrow doses from two different exposures, Maxilla incisor and Molar bite-wing, were calculated to be 0.4 and 1.0 mrad respectively. The average dose to red bone marrow from a full-mouth examination (10 exposures) was 0.7 mrad/exposure. An orthopantomographic examination involved 2 mrad to the bone marrow. The greatest doses from an orthopantomographic examination were found around the lateral rotational axis, namely 700 mrad. The dose distributions from the two different cone lengths did not differ as much as expected, mainly due to scattered radiation.

  3. In-vivo (entrance) dose measurements in external beam radiotherapy with aqueous FBX dosimetry system

    International Nuclear Information System (INIS)

    Semwal, M.K.; Thakur, P.K.; Bansal, A.K.; Vidyasagar, P.B.

    2005-01-01

    FBX aqueous chemical dosimetry system has been found useful in radiotherapy owing to its low dose measuring capability. In the present work, entrance dose measurements in external beam radiotherapy on a telecobalt machine were carried out with the system on 100 patients. Treatments involving simple beam arrangement of open parallel-opposed beams in cranial and pelvic irradiations were selected for this study. In place of a spectrophotometer, a simple and inexpensive colorimeter was used for absorbance measurements. The purpose was to assess the efficacy of the FBX system for in-vivo dose measurements. The results obtained show that the average discrepancy between the measured and expected dose for both categories of patients was 0.2% (standard deviation 3.2%) with a maximum of +1 0.3%. There were 5.5% cases showing more than ± 5% discrepancy. Comparison of the results obtained with published work on entrance dose measurements, with diode detectors, shows that the inexpensive FBX system can be used for in-vivo (entrance) dose measurements for simple beam arrangements in radiotherapy and can thus serve as a useful QA tool. (author)

  4. Radiochromic film calibration for low-energy seed brachytherapy dose measurement

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Hali, E-mail: hamorris@ualberta.ca; Menon, Geetha; Sloboda, Ron S. [Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada and Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada)

    2014-07-15

    Purpose: Radiochromic film dosimetry is typically performed for high energy photons and moderate doses characterizing external beam radiotherapy (XRT). The purpose of this study was to investigate the accuracy of previously established film calibration procedures used in XRT when applied to low-energy, seed-based brachytherapy at higher doses, and to determine necessary modifications to achieve similar accuracy in absolute dose measurements. Methods: Gafchromic EBT3 film was used to measure radiation doses upwards of 35 Gy from 75 kVp, 200 kVp, 6 MV, and (∼28 keV) I-125 photon sources. For the latter irradiations a custom phantom was built to hold a single I-125 seed. Film pieces were scanned with an Epson 10000XL flatbed scanner and the resulting 48-bit RGB TIFF images were analyzed using both FilmQA Pro software andMATLAB. Calibration curves relating dose and optical density via a rational functional form for all three color channels at each irradiation energy were determined with and without the inclusion of uncertainties in the measured optical densities and dose values. The accuracy of calibration curve variations obtained using piecewise fitting, a reduced film measurement area for I-125 irradiation, and a reduced number of dose levels was also investigated. The energy dependence of the film lot used was also analyzed by calculating normalized optical density values. Results: Slight differences were found in the resulting calibration curves for the various fitting methods used. The accuracy of the calibration curves was found to improve at low doses and worsen at high doses when including uncertainties in optical densities and doses, which may better represent the variability that could be seen in film optical density measurements. When exposing the films to doses > 8 Gy, two-segment piecewise fitting was found to be necessary to achieve similar accuracies in absolute dose measurements as when using smaller dose ranges. When reducing the film measurement

  5. Measurement with total scatter calibrate factor at different depths in the calculation of prescription dose

    International Nuclear Information System (INIS)

    Li Lijun; Zhu Haijun; Zhang Xinzhong; Li Feizhou; Song Hongyu

    2004-01-01

    Objective: To evaluate the method of measurement of total scatter calibrate factor (Sc, p). Methods: To measure the Sc, p at different depths on central axis of 6MV, 15MV photon beams through different ways. Results: It was found that the measured data of Sc, p changed with the different depths to a range of 1% - 7%. Using the direct method, the Sc, p measured depth should be the same as the depth in dose normalization point of the prescription dose. If the Sc, p (fsz, d) was measured at the other depths, it could be obtained indirectly by the calculation formula. Conclusions: The Sc, p in the prescription dose can be obtained either by the direct measure method or the indirect calculation formula. But emphasis should be laid on the proper measure depth. (authors)

  6. Absorbed dose measurement by using tissue equivalent ionization chamber (pair ionization chamber) in the Yayoi reactor

    International Nuclear Information System (INIS)

    Sasuga, N.; Okamura, K.; Terakado, T.; Mabuchi, Y.; Nakagawa, T.; Sukegawa, Toshio; Aizawa, C.; Saito, I.; Oka, Yoshiaki

    1998-01-01

    Each dose rate of neutron and gamma ray in the thermal column of the Yayoi reactor, in which an epithermal neutron field will be used for the boron neutron capture therapy, was measured by using a tissue equivalent ionization chamber and a graphite chamber. The tissue equivalent ionization chamber has some response to both neutron and gamma ray, but the graphite chamber has a few response to the neutron, so called pair ionization chamber method. The epithermal neutron fluxes of the thermal column were calculated by ANISN (one dimensional neutron-gamma transport code). A measured value for gamma dose rate by the pair ionization chamber agrees relevantly with a calculated result. For neutron dose rate, however, the measured value was too much small in comparison with the calculated result. The discrepancy between the measured value and the calculated result for neutron dose rate is discussed in detail in the report. (M. Suetake)

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

    Science.gov (United States)

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

    2015-02-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  9. Measurements Of Fingers Doses Of Staff Members In Nuclear Medicine Department

    International Nuclear Information System (INIS)

    AL LEHYANI, S.H.; SHOUSHA, H.A.; HASSAN, R.A.

    2009-01-01

    For some occupationally radiation exposed groups, the hands are more heavily exposed to ionizing radiation than the rest of the body. The Egyptian Atomic Energy Authority runs an extensive personal dosimetry service in Egypt, but finger doses have not been measured to a wide extent. In this study, the finger doses were measured for five different nuclear medicine staff occupational groups for which heavy irradiation of the hands was suspected. Finger doses were measured for nuclear medicine physicians, technologists, nurses and physicists. The nuclear medicine staff working with the radioactive materials wears two TLD dosimeters during the whole period, which lasted from 1 to 4 weeks. The staff performs their work on a regular basis throughout the month, and means annual doses were calculated for these groups. The doses to the fingers for the 99m Tc technologists and nurses of groups (2) and (3) were observed to be 30.24 ± 14.5 μSv/GBq (mean ± SD) and 30.37 ± 17.5 μSv/GBq, respectively. Similarly, the dose to the fingers for the 131 I technologists in group (5) was estimated to be 126.13 ± 38.2μSv/GBq. Finger doses for the physicians could not be calculated per unit of activity because they did not handle the radiopharmaceuticals directly but their doses were reported in millisieverts that accumulated in 1 week. The doses to the fingers of the physicist were 16.3±7.7 μSv/GBq. The maximum average finger dose in this study was found to be 2.8 mSv for the technologists handled therapeutic 131 I (group 5). It could be concluded that the maximum expected annual dose to the extremities appeared to be less than the annual limit (500 mSv/y).

  10. Basic evaluation of signal transmission in a real-time internal radiation dose measurement system

    International Nuclear Information System (INIS)

    Shinohe, K.; Takura, T.; Sato, F.; Matsuki, H.; Yamada, S.; Sato, T.

    2009-01-01

    In radiation therapy, excessive exposure to radiation occurs because the dose actually delivered to the tumor is not known. As a result, a patient suffers from side effects. To solve this problem, a system is needed in which the delivered dose is measured inside the body and the dose data are transmitted from inside to outside of the body during radiation therapy. If such a system is realized, it will be possible to treat cancer safely and effectively. The proposed real-time internal radiation dose measurement system consists of an implantable dosimeter, a wireless communication system, and a wireless feeding system. In this study, a wireless communication system that uses magnetic fields was investigated. As a result, a communication distance of 200 mm was obtained. It was confirmed that radiation dose data could be transmitted outside the body when the communication distance is the required 200 mm. (author)

  11. Measurement of secondary cosmic radiation and calculation of associated dose conversion coefficients for humans

    International Nuclear Information System (INIS)

    Simmer, Gregor

    2012-01-01

    Due to secondary cosmic radiation (SCR), pilots and flight attendants receive elevated effective doses at flight altitudes. For this reason, since 2003 aircrew members are considered as occupationally exposed, in Germany. This work deals with the calculation of dose conversion coefficients (DCC) for protons, neutrons, electrons, positrons, photons and myons, which are crucial for estimation of effective dose from SCR. For the first time, calculations were performed combining Geant4 - a Monte Carlo code developed at CERN - with the voxel phantoms for the reference female and male published in 2008 by ICRP and ICRU. Furthermore, measurements of neutron fluence spectra - which contribute the major part to the effective dose of SCR - were carried out at the Environmental Research Station Schneefernerhaus (UFS) located at 2650 m above sea level nearby the Zugspitze mountain, Germany. These measured neutron spectra, and additionally available calculated spectra, were then folded with the DCC calculated in this work, and effective dose rates for different heights were calculated.

  12. Long distance elementary measurement of the radiation dose ratio produced by neutron activation

    International Nuclear Information System (INIS)

    Zhou Changgeng; Lou Benchao; Wu Chunlei; Hu Yonghong; Li Yan

    2009-04-01

    The working principle and the structure and performances of a long distance controllable individual radiation dose ratio instrument are described. The radiation dose ratio produced by neutron activation is elementarily measured by using this instrument in the neutron generator hall with high neutron yield. When neutron yield arrives to 2 x 10 11 s -1 , the radiation dose ratio produced by neutron activation is 99.9 μSv/h in 1 h after the generator being stopped. The radiation dose ratio is reduced to 24.4 μSv/h in 39 h after the generator being stopped. When neutron yield is 3.2 x 10 10 s -1 , the radiation dose ratio produced by neutron activation is 21.9 μSv/h in 36 min, after the generator being stopped. The measurement results may provide reference for physical experimenters and neutron generator operators. (authors)

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  14. Radiation doses measured by TLD (thermo luminescent dosimeter) in x-ray examination

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi; Hiraki, Motoji; Murakami, Shozo; Nishikawa, Naozo; Yagi, Takayuki

    1977-01-01

    By means of TLD, we measured the radiation doses to the skin in the central area of the field of radiation and doses scattered outside of the radiation field, utilizing a phantom to define a suitable radiation field. Clinically, when radiography of the gall bladder and the chest was done, we measured both the radiation doses of the central skin area where radiation was done and the skin above the area of the female gonads. In radiography of the chest, the radiation doses to the skin area above the female gonads situate was under 0.1 mR. When female gonads are less than 15 cm from the margin of the radiation field of the radiation dose can be decreased by 30% if gum sheets containing lead are used to cover the skin area outside the radiation field. (auth.)

  15. Peripheral reactions

    International Nuclear Information System (INIS)

    Greiner, D.

    1978-01-01

    Peripheral collisions, that is, collisions involving a small amount of overlap of nuclear matter, are discussed including inclusive interactions, the magnitude of the peripheral cross section, fragmentation, a compilation of experiments and available data, limiting fragmentation, factorization, some models, fragment momentum distributions, and future research directions

  16. Bone mineral density measurements using peripheral quantitative computed tomography (pQCT). An evaluation of its clinical utility

    International Nuclear Information System (INIS)

    Imai, Yoshiyuki

    1999-01-01

    Bone densitometry has become a major tool for the risk assessment of osteoporosis. Peripheral quantitative computed tomography (pQCT) has the potential to measure true volumetric bone mineral density (BMD, g/cm 3 ) separating cortical and trabecular BMD. The most widely used dual-energy X-ray absorptiometry (DXA) provides areal BMD (mg/cm 2 ). The purpose of this study was to clarify the clinical usefulness of pQCT as a method for bone mineral measurement. The pQCT measurements were carried out at the ultradistal- and mid-radius and the tibia using a Densiscan-1000 (Scanco Medical AG). In both sexes, radial and tibial BMDs in the elderly group (aged more than 60 y.o., 17 men, and 26 women) were significantly lower than those in the young group (aged 20-44 y.o., 107 men and 78 women). The percent difference between the two groups was the greatest in trabecular BMD (D50). As to the sex-related difference, the mean values of radial and tibial BMD in men were significantly higher than in women in elderly groups. The radial BMDs measured by pQCT correlated significantly with BMDs in the lumbar spine, radius and femoral neck measured by DXA (p<0.001). Lumbar BMD measured by DXA showed the highest correlation to rD50 measured by pQCT. Diagnostic ability of pQCT and DXA to detect osteoporosis was determined by comparing BMD measurements. Kappa statistics showed that in general the diagnostic agreement between these measurements was fair or moderate. The discriminative ability of these methods for vertebral fracture was assessed by receiver operating characteristic (ROC) analysis. The areas under the ROC curves were 0.68, 0.71, 0.69 and 0.78 for D50, D100, P100 and L-BMD, respectively. These results indicate that BMD measurements made by pQCT can provide information regarding both trabecular and cortical BMD, and that this method has potential for the diagnosis and management of osteoporosis. (author)

  17. The current status of eye lens dose measurement in interventional cardiology personnel in Thailand.

    Science.gov (United States)

    Krisanachinda, Anchali; Srimahachota, Suphot; Matsubara, Kosuke

    2017-06-01

    Workers involved in interventional cardiology procedures receive high eye lens doses if radiation protection tools are not properly utilized. Currently, there is no suitable method for routine measurement of eye dose. In Thailand, the eye lens equivalent doses in terms of Hp(3) of the interventional cardiologists, nurses, and radiographers participating in interventional cardiology procedures have been measured at 12 centers since 2015 in the pilot study. The optically stimulated luminescence (OSL) dosimeter was used for measurement of the occupational exposure and the eye lens dose of 42 interventional cardiology personnel at King Chulalongkorn Memorial Hospital as one of the pilot centers. For all personnel, it is recommended that a first In Light OSL badge is placed at waist level and under the lead apron for determination of Hp(10); a second badge is placed at the collar for determination of Hp(0.07) and estimation of Hp(3). Nano Dots OSL dosimeter has been used as an eye lens dosimeter for 16 interventional cardiology personnel, both with and without lead-glass eyewear. The mean effective dose at the body, equivalent dose at the collar, and estimated eye lens dose were 0.801, 5.88, and 5.70 mSv per year, respectively. The mean eye lens dose measured by the Nano Dots dosimeter was 8.059 mSv per year on the left eye and 3.552 mSv per year on the right eye. Two of 16 interventional cardiologists received annual eye lens doses on the left side without lead glass that were higher than 20 mSv per year, the new eye lens dose limit as recommended by ICRP with the risk of eye lens opacity and cataract.

  18. DNA methylation changes measured in pre‐diagnostic peripheral blood samples are associated with smoking and lung cancer risk

    Science.gov (United States)

    Baglietto, Laura; Ponzi, Erica; Haycock, Philip; Hodge, Allison; Bianca Assumma, Manuela; Jung, Chol‐Hee; Chung, Jessica; Fasanelli, Francesca; Guida, Florence; Campanella, Gianluca; Chadeau‐Hyam, Marc; Grankvist, Kjell; Johansson, Mikael; Ala, Ugo; Provero, Paolo; Wong, Ee Ming; Joo, Jihoon; English, Dallas R.; Kazmi, Nabila; Lund, Eiliv; Faltus, Christian; Kaaks, Rudolf; Risch, Angela; Barrdahl, Myrto; Sandanger, Torkjel M.; Southey, Melissa C.; Giles, Graham G.; Johansson, Mattias; Vineis, Paolo; Polidoro, Silvia; Relton, Caroline L.

    2016-01-01

    DNA methylation changes are associated with cigarette smoking. We used the Illumina Infinium HumanMethylation450 array to determine whether methylation in DNA from pre‐diagnostic, peripheral blood samples is associated with lung cancer risk. We used a case‐control study nested within the EPIC‐Italy cohort and a study within the MCCS cohort as discovery sets (a total of 552 case‐control pairs). We validated the top signals in 429 case‐control pairs from another 3 studies. We identified six CpGs for which hypomethylation was associated with lung cancer risk: cg05575921 in the AHRR gene (p‐valuepooled = 4 × 10−17), cg03636183 in the F2RL3 gene (p‐valuepooled = 2 × 10 − 13), cg21566642 and cg05951221 in 2q37.1 (p‐valuepooled = 7 × 10−16 and 1 × 10−11 respectively), cg06126421 in 6p21.33 (p‐valuepooled = 2 × 10−15) and cg23387569 in 12q14.1 (p‐valuepooled = 5 × 10−7). For cg05951221 and cg23387569 the strength of association was virtually identical in never and current smokers. For all these CpGs except for cg23387569, the methylation levels were different across smoking categories in controls (p‐valuesheterogeneity ≤ 1.8 x10 − 7), were lowest for current smokers and increased with time since quitting for former smokers. We observed a gain in discrimination between cases and controls measured by the area under the ROC curve of at least 8% (p‐values ≥ 0.003) in former smokers by adding methylation at the 6 CpGs into risk prediction models including smoking status and number of pack‐years. Our findings provide convincing evidence that smoking and possibly other factors lead to DNA methylation changes measurable in peripheral blood that may improve prediction of lung cancer risk. PMID:27632354

  19. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    International Nuclear Information System (INIS)

    Aragno, D.; Fattibene, P.; Onori, S.

    2000-01-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO 2 -signal of intensity similar to that induced by a dose of about 2 mGy of 60 Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60 Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined. (author)

  20. The radiation dose from a proposed measurement of arsenic and selenium in human skin

    Energy Technology Data Exchange (ETDEWEB)

    Gherase, Mihai R; Mader, Joanna E; Fleming, David E B, E-mail: mgherase@mta.c [Department of Physics, Mount Allison University, 67 York Street, Sackville, NB E4L 1E6 (Canada)

    2010-09-21

    Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrometer was used for all measurements. The setup included a stainless steel lid which served as a radiation shield. Two rectangular polyethylene skin/soft tissue phantoms with two cylindrical plaster of Paris bone phantoms were used to study the effect of x-ray beam attenuation and backscatter on the measured dose. Eight different irradiation experiments were performed. The average dose rate values measured with TLD chips within a 1 x 1 cm{sup 2} area were between 4.8 and 12.8 mGy min{sup -1}. The equivalent dose for a 1 x 1 cm{sup 2} skin area was estimated to be 13.2 mSv. The maximum measured dose rate values with a single TLD chip were between 7.5 and 25.1 mGy min{sup -1}. The effective dose corresponding to a proposed arsenic/selenium skin measurement was estimated to be 0.13 {mu}Sv for a 2 min irradiation.

  1. BeO-OSL detectors for dose measurements in cell cultures

    International Nuclear Information System (INIS)

    Andreeff, M.; Freudenberg, R.; Kotzerke, J.; Sommer, D.; Reichelt, U.; Henniger, J.

    2009-01-01

    Aim: The absorbed dose is an important parameter in experiments involving irradiation of cells in vitro with unsealed radionuclides. Typically, this is estimated with a model calculation, although the results thus obtained cannot be verified. Generally used real-time measurement methods are not applicable in this setting. A new detector material with in vitro suitability is the subject of this work. Methods: Optically-stimulated luminescence (OSL) dosimeters based on beryllium oxide (BeO) were used for dose measurement in cell cultures exposed to unsealed radionuclides. Their qualitative properties (e. g. energy-dependent count rate sensitivity, fading, contamination by radioactive liquids) were determined and compared to the results of a Monte Carlo simulation (using AMOS software). OSL dosimeters were tested in common cell culture setups with a known geometry. Results: Dose reproducibility of the OSL dosimeters was ± 1.5%. Fading at room temperature was 0.07% per day. Dose loss (optically-stimulated deletion) under ambient lighting conditions was 0.5% per minute. The Monte Carlo simulation for the relative sensitivity at different beta energies provided corresponding results to those obtained with the OSL dosimeters. Dose profile measurements using a 6 well plate and 14 ml PP tube showed that the geometry of the cell culture vessel has a marked influence on dose distribution with 188 Re. Conclusion: A new dosimeter system was calibrated with β-emitters of different energy. It turned out as suitable for measuring dose in liquids. The dose profile measurements obtained are suitably precise to be used as a check against theoretical dose calculations. (orig.)

  2. The precision of radiotherapy in Gliwice, Poland, estimated by in vivo dose measurements

    International Nuclear Information System (INIS)

    Orlef, A.; Lobodziec, W.; Maniakowski, Z.

    1995-01-01

    The aim of this work was to evaluate the precision of irradiation using gamma Co-60 Philips Unites and linear accelerators Neptun 10p and Saturne II+ which generate X-rays of 9MV and 23MV respectively. This work has been undertaken for the reason that the effect of radiotherapy of cancer is strongly dependent of the precision of the dose delivery to a patient. The in vivo dose measurements were performed using a p-type silicon diodes (EDE-5, EDP-20, EDP-30) connected to a DPD-510 electrometer (Scanditronix). The diodes were calibrated by comparison their response to a 0.6cm 3 ionization chamber (NE 2571) placed at the relevant depth in the phantom. The entrance and exit dose calibration factors have been determined for reference conditions (constant SSD, field, temperature, ...). For conditions different from reference one the correction factors have been evaluated. The 855 in vivo dose measurements of entrance dose were performed. The histograms of percentage differences between measured and planed entrance dose has been constructed and analyzed. The average values of such differences were: -1.3%, 4.0%, -0.9% for gamma Co-60, X 9MV, X 23MV, respectively. These values can be interpreted as systematic uncertainties. The standard deviations (SD) were found as: 3.1%, 4.1%, 3.5%. These parameters can be considered as a random uncertainties. The 546 cases of dose at the reference point for head and neck cancer have been evaluated taking into account the entrance and exit measured doses. The average difference between those values and planned one was 1.3% and SD = 5.1%. There were observed the changes of the dimensions of the irradiated tissue block during the radiotherapy. This had a significant influence on the differences between delivered (measured) and planed doses at reference point

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  4. Comparison of 3-dimensional dose reconstruction system between fluence-based system and dose measurement-guided system

    Energy Technology Data Exchange (ETDEWEB)

    Nakaguchi, Yuji, E-mail: nkgc2003@yahoo.co.jp [Department of Radiological Technology, Kumamoto University Hospital, Kumamoto (Japan); Ono, Takeshi [Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Onitsuka, Ryota [Graduate School of Health Sciences, Kumamoto University, Kumamoto (Japan); Maruyama, Masato; Shimohigashi, Yoshinobu; Kai, Yudai [Department of Radiological Technology, Kumamoto University Hospital, Kumamoto (Japan)

    2016-10-01

    COMPASS system (IBA Dosimetry, Schwarzenbruck, Germany) and ArcCHECK with 3DVH software (Sun Nuclear Corp., Melbourne, FL) are commercial quasi-3-dimensional (3D) dosimetry arrays. Cross-validation to compare them under the same conditions, such as a treatment plan, allows for clear evaluation of such measurement devices. In this study, we evaluated the accuracy of reconstructed dose distributions from the COMPASS system and ArcCHECK with 3DVH software using Monte Carlo simulation (MC) for multi-leaf collimator (MLC) test patterns and clinical VMAT plans. In a phantom study, ArcCHECK 3DVH showed clear differences from COMPASS, measurement and MC due to the detector resolution and the dose reconstruction method. Especially, ArcCHECK 3DVH showed 7% difference from MC for the heterogeneous phantom. ArcCHECK 3DVH only corrects the 3D dose distribution of treatment planning system (TPS) using ArcCHECK measurement, and therefore the accuracy of ArcCHECK 3DVH depends on TPS. In contrast, COMPASS showed good agreement with MC for all cases. However, the COMPASS system requires many complicated installation procedures such as beam modeling, and appropriate commissioning is needed. In terms of clinical cases, there were no large differences for each QA device. The accuracy of the compass and ArcCHECK 3DVH systems for phantoms and clinical cases was compared. Both systems have advantages and disadvantages for clinical use, and consideration of the operating environment is important. The QA system selection is depending on the purpose and workflow in each hospital.

  5. Review of techniques and detectors used in instruments for field measurement of β doses and dose rates

    International Nuclear Information System (INIS)

    Jones, A.R.

    1984-01-01

    Generally, field measurements are required to assess the hazard from β-rays before personnel are allowed to occupy a working space or perform a task. Occasionally, the measurements are required for an assessment after a β-ray exposure is suspected to have occurred. With these uses of field instruments in mind, the following detectors and associated techniques will be discussed in terms of the measurement principles, advantages, and limitations: 1) thin-walled ion chambers (sometimes in combination with thick-walled ones or with covers thick enough to prevent penetration of β-particles); 2) thin scintillators, nearly tissue equivalent, to provide a detector analogous to skin; 3) scintillators, thick enough to absorb all the energy of the β-particles. Circuitry is required to count pulses according to size to permit calculation of dose or dose rate; 4) silicon diodes with thin detection layers operated as photocurrent generators; 5) silicon diodes, reversed biassed, with pulses counted according to size; 6) simple pulse counters (e.g., GM counters or silicon diodes with thin windows)

  6. Phantom measurements and computed estimates of breast dose with radiotherapy for Hodgkin's lymphoma: dose reduction with the use of the involved field

    International Nuclear Information System (INIS)

    Wirth, A.; Kron, T.; Sorell, G.; Cramb, J.; Wittwer, H.; Sullivan, K.

    2008-01-01

    Full text: The risk of breast cancer following radiotherapy for Hodgkin's lymphoma appears to be dose related. In this study we compared breast dose in an anthropomorphic phantom for conventional 'mantle'; upper mediastinal/bilateral neck (minimantle) and unilateral neck fields, and evaluated the accuracy of computer planned dose estimates for out-of-field doses. For each field, computer-planned breast dose (CPD) estimates were compared with thermolu-minescence dosimetry measurements in five locations within 'breast tissue'. CPD were also compared with ion chamber measurements in a slab phantom. Measured dose and CPD were within 20% of each other up to approximately 10 cm from the field edge. Beyond 10 cm, the CPD underestimated dose by a factor of 2 or more. The minimantle reduced the breast dose by a factor of approximately 10 compared with the mantle treatment. Treating the neck field lowered the breast dose by a further 50% or more. Modern involved-field radiotherapy for lymphoma substantially reduces breast dose compared with mantle fields. Computer dosimetery underestimated dose at larger distances from the field. This needs to be considered if computer dosimetery is used to estimate breast dose and, by extrapolation, breast cancer risk.

  7. Organ dose evaluation for CT scans based on in-phantom measurements

    International Nuclear Information System (INIS)

    Liu Haikuan; Zhuo Weihai; Chen Bo; Yi Yanling; Li Dehong

    2009-01-01

    Objective: To explore the organ doses and their distributions in different projections of CT scans. Methods: The CT values were measured and the linear absorption coefficients were derived for the main organs of the anthropomorphic phantom to compare with the normal values of human beings. The radiophotoluminescent glass dosimeters were set into various tissues or organs of the phantom for mimic measurements of the organ doses undergoing the head, chest, abdomen and pelvis CT scans, respectively. Results: The tissue equivalence of the phantom used in this study was good. The brain had the largest organ dose undergoing the head CT scan. The organ doses in thyroid, breast, lung and oesophagus were relatively large in performing the chest CT scan, while the liver, stomach, colon and lung had relatively hrge organ doses in abdomen CT practice. The doses in bone surface and colon exceeded by 50 mGy in a single pelvis CT scan. Conclusions: The organ doses and their distributions largely vary with different projections of CT scans. The organ doses of colon, bone marrow,gonads and bladder are fairly large in performing pelvis CT scan, which should be paid attention in the practice. (authors)

  8. Surface dose measurements and comparison of unflattened and flattened photon beams

    Directory of Open Access Journals (Sweden)

    Ashokkumar Sigamani

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the central axis dose in the build-up region and the surface dose of a 6 MV and 10 MV flattened photon beam (FB and flattening filter free (FFF therapeutic photon beam for different square field sizes (FSs for a Varian Truebeam linear accelerator using parallel-plate ionization chamber and Gafchromic film. Knowledge of dosimetric characteristics in the build-up region and surface dose of the FFF is essential for clinical care. The dose measurements were also obtained empirically using two different commonly used dosimeters: a p-type photon semiconductor dosimeter and a cylindrical ionization chamber. Surface dose increased linearly with FS for both FB and FFF photon beams. The surface dose values of FFF were higher than the FB FSs. The measured surface dose clearly increases with increasing FS. The FFF beams have a modestly higher surface dose in the build-up region than the FB. The dependence of source to skin distance (SSD is less significant in FFF beams when compared to the flattened beams at extended SSDs.

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  10. Spherical ionization chamber of 14 liter for precise measurement of environmental radiation dose rate

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

    1991-05-01

    A spherical ionization chamber of 14 liter filled with 1 atm. nitrogen gas was arranged aiming at precise measurement of dose rate due to environmental gamma rays and cosmic rays. Ionization current-dose rate conversion factor for this ionization chamber was derived from careful consideration taking into account the attenuation by chamber wall, ionization current due to alpha particles and so on. Experiments at calibrated gamma ray fields and intercomparison with NaI(Tl) scintillation detector were also performed, which confirmed this ionization chamber using the conversion factor can measure the dose rate with an error of only a few percent. This ionization chamber will be used for measurement of environmental gamma ray and cosmic ray dose rate. (author)

  11. Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures

    Energy Technology Data Exchange (ETDEWEB)

    Safari, M. J.; Wong, J. H. D.; Ng, K. H., E-mail: ngkh@um.edu.my [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Jong, W. L. [Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Cutajar, D. L.; Rosenfeld, A. B. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2015-05-15

    Purpose: The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. Methods: The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit. Results: The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (±1%), field size (±1%), frame rate (±3%), or beam energy (±5%). The detector angular dependence was within ±5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ±3%. Conclusions: The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.

  12. Radiation protection in medicine (542) comparison of different dosimetry systems for dose measurements in diagnostic radiology

    International Nuclear Information System (INIS)

    Milkovic, D.; Ranogajec-Komor, M.; Miljanic, S.; Knezevic, Z.; Krpan, K.

    2006-01-01

    The dose measurement on patients in X-ray diagnostic is not simple, because low doses with low and various energies have to be measured. The aim of this preliminary study was to compare high sensitivity thermoluminescent dosimeter (T.L.D.) (LiF:Mg,Cu,P) and radio-photoluminescent (R.P.L.) glass dosimeters for dose measurements in routine X-ray diagnostic of chest of children. The energy dependence of the dosimeters was investigated in Secondary Standard Dosimetry Laboratory (SSDL). The energy range was 33- 65 keV mean energy, the dosimeters were placed free in air and on the water phantom. The results were compared to calculated values of Hp(10). The next step was the irradiation in a routine X-ray diagnostic unit. Irradiations were performed by the Shimadzu X-ray unit. The selected irradiation conditions were the same as that most commonly used for baby examinations. Doses were measured with dosimeters placed free-in-air and also with the dosimeters placed on the water phantom and baby phantom. The results show that the R.P.L. glass dosimeters and LiF:Mg,Cu,P based T.L.D. are suitable for low dose measurements in X-ray diagnostic. The uncertainty of dose determination is mainly caused by the energy dependence of dosimeters. (authors)

  13. Assessment of micro-dose biplanar radiography in lower limb measurements in children

    International Nuclear Information System (INIS)

    Lerisson, Heloise; Amzallag-Bellenger, Elisa; Cebulski-Delebarre, Aurelie; Boutry, Nathalie; Nectoux, Eric; Herbaux, Bernard; Desmulliez, Geoffrey; Duhamel, Alain; Drumez, Elodie

    2018-01-01

    To evaluate in children microdose protocol compared with low dose for lower limb alignment (LLA) measurements on biplanar radiography. Children 6 years or older were included. Height, weight a