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https://www.readbyqxmd.com/read/28103113/micronuclei-as-a-marker-for-medical-screening-of-subjects-continuously-occupationally-exposed-to-low-doses-of-ionizing-radiation
#1
Smj Mortazavi, Sar Mortazavi, Maryam Paknahad
No abstract text is available yet for this article.
January 19, 2017: Biomarkers: Biochemical Indicators of Exposure, Response, and Susceptibility to Chemicals
https://www.readbyqxmd.com/read/28102956/experimental-verification-of-4d-monte-carlo-simulations-of-dose-delivery-to-a-moving-anatomy
#2
Sara Gholampourkashi, Miro Vujicic, Jason Belec, Joanna E Cygler, Emily Heath
PURPOSE: To evaluate a novel 4D Monte Carlo simulation tool by comparing calculations to physical measurements using a respiratory motion phantom. METHODS: We used a dynamic Quasar phantom in both stationary and breathing states (sinusoidal motion of amplitude of 1.8 cm and period of 3.3 s) for dose measurements on an Elekta Agility linear accelerator. Gafchromic EBT3 film and the RADPOS 4D dosimetry system were placed inside the lung insert of the phantom to measure dose profiles and point-dose values at the center of the spherical tumor inside the insert...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102954/dosimetric-impact-of-lipiodol-in-stereotactic-body-radiation-therapy-on-liver-after-trans-arterial-chemoembolization
#3
Daisuke Kawahara, Shuichi Ozawa, Akito Saito, Teiji Nishio, Tomoki Kimura, Tatsuhiko Suzuki, Kazunari Hioki, Takeo Nakashima, Yoshimi Ohno, Yuji Murakami, Yasushi Nagata
PURPOSE: Stereotactic body radiation therapy (SBRT) combining trans-arterial chemoembolization (TACE) with Lipiodol is expected to improve local control. This study is aimed to estimate the dose enhancement in Lipiodol's proximity and to evaluate the dose calculation accuracy of the Acuros XB (AXB) algorithm and anisotropic analytical algorithm (AAA) in the Eclipse treatment planning system (TPS) (ver. 11, Varian Medical Systems, Palo Alto, USA), compared with that of the Monte Carlo (MC) calculation (using BEAMnrc/DOSXYZnrc code) for a virtual phantom and a treatment plan for liver SBRT after TACE...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102953/air-kerma-strength-determination-of-an-hdr-192-ir-source-including-a-geometric-sensitivity-study-of-the-seven-distance-method
#4
Blake R Smith, John A Micka, Manik Aima, Larry A DeWerd, Wesley S Culberson
PURPOSE: To perform an in-air air-kerma strength (SK) calibration of the Bebig model Ir2.A85-2 192Ir high-dose rate (HDR) brachytherapy source manufactured by Mallinckrodt Medical (Westerduinweg, Germany) with the NIST-traceable seven-distance technique established by the University of Wisconsin. A comparison was made between the reference air-kerma rate (RAKR) reported on a certificate from the Physikalisch-Technische Bundesanstalt (Berlin, Germany) (PTB) primary laboratory and the SK determined at the University of Wisconsin Madison Radiation Research Center (UWMRRC)...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102948/use-of-parallel-plate-ionization-chambers-in-reference-dosimetry-of-novac-and-liac-%C3%A2-mobile-electron-linear-accelerators-for-intraoperative-radiotherapy-a-multi-center-survey
#5
Paolo Scalchi, Alessia Ciccotelli, Giuseppe Felici, Assunta Petrucci, Raffaella Massafra, Valeria Piazzi, Paola D'Avenia, Francesca Cavagnetto, Federica Cattani, Raffaella Romagnoli, Antonella Soriani
PURPOSE: LIAC(®) and NOVAC are two mobile linear accelerators dedicated to intraoperative radiation therapy (IORT), generating electron beams in the energy range of 3-12 MeV. Due to high dose-per-pulse (up to 70 mGy per pulse), in 2003 the Italian National Institute of Health (ISS) stated that "for the measure of dose to water in reference conditions, ionization chambers cannot be employed and no published dosimetry protocol can be used". As a consequence, ferrous sulphate (or, alternatively alanine) dosimetry was recommended...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102946/a-portal-dosimetry-dose-prediction-method-based-on-collapsed-cone-algorithm-using-the-clinical-beam-model
#6
J Martínez Ortega, N Gómez González, P Castro Tejero, M Pinto Monedero, N B Tolani, L Núñez Martín, R Sánchez Montero
PURPOSE: Amorphous silicon electronical portal imaging devices (EPIDs) are widely used for dosimetric measurements in Radiation Therapy. The purpose of this work was to determine if a portal dose prediction method can be utilized for dose map calculations based on the linear accelerator model within a commercial treatment planning system (Pinnacle(3) v8.0 m). METHODS: The method was developed for a 6 MV photon beam on the Varian Clinac 21-EX, at a nominal dose rate of 400 MU/min...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102944/a-simple-and-robust-trajectory-based-stereotactic-radiosurgery-treatment
#7
Byron Wilson, Karl Otto, Ermias Gete
INTRODUCTION: We present a Trajectory-based Volumetric Modulated Arc Therapy (TVMAT) technique for Stereotactic Radiosurgery (SRS) that takes advantage of a modern linacs ability to modulate dose rate and move the couch dynamically. In addition, we investigate the quality of the developed TVMAT method and the dosimetric accuracy of the technique. METHODS: The main feature of the TVMAT technique is a standard beam trajectory formed by dynamic motion of the treatment couch and the linac gantry...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102829/absorbed-dose-evaluation-of-auger-electron-emitting-radionuclides-impact-of-input-decay-spectra-on-dose-point-kernels-and-s-values
#8
Nadia Falzone, Boon Lee, José Fernández-Varea, Christiana Kartsonaki, Andrew Stuchbery, Tibor Kibedi, Katherine Vallis
AIM: The aim of this study was to investigate the impact of decay data provided by the newly developed stochastic atomic relaxation model <i>BrIccEmis</i> on dose point kernels (DPKs- radial dose distribution around a unit point source) and <i>S</i>-values (absorbed dose per unit cumulated activity) of 14 Auger electron (AE) emitting radionuclides, namely <sup>67</sup>Ga, <sup>80m</sup>Br, <sup>89</sup>Zr, <sup>90</sup>Nb, <sup>99m</sup>Tc, <sup>111</sup>In, <sup>117m</sup>Sn, <sup>119</sup>Sb, <sup>123</sup>I, <sup>124</sup>I, <sup>125</sup>I, <sup>135</sup>La, <sup>195m</sup>Pt and <sup>201</sup>Tl...
January 19, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28102696/compression-forces-used-in-the-norwegian-breast-cancer-screening-program
#9
Gunvor G Waade, Nataliia Moshina, Sofie Sæbuødegård, Peter Hogg, Solveig Hofvind
OBJECTIVES: Compression is used in mammography to reduce breast thickness, which is claimed to improve image quality and reduce radiation dose. In the XXX Breast Cancer Screening Program (XBCSP), the recommended range of compression force for full field digital mammography is 11-18 kg (108-177 Newton [N]). This is the first study to investigate the compression force used in the program. METHODS: The study included information from 17,951 randomly selected women screened with FFDM at 14 breast centres in the XBCSP, January-March 2014...
January 19, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28102693/a-phantom-study-for-ground-glass-nodule-detectability-using-chest-digital-tomosynthesis-with-iterative-reconstruction-algorithm-by-ten-observers-association-with-radiation-dose-and-nodular-characteristics
#10
Katsunori Miyata, Yukihiro Nagatani, Mitsuru Ikeda, Masashi Takahashi, Norihisa Nitta, Satoru Matsuo, Shinichi Ohta, Hideji Otani, Ayumi Nitta-Seko, Yoko Murakami, Keiko Tsuchiya, Akitoshi Inoue, Sayaka Misaki, Khishigdorj Erdenee, Tetsuo Kida, Kiyoshi Murata
OBJECTIVES: To compare detectability of simulated ground glass nodules (GGN) on chest digital tomosynthesis (CDT) among 12 images obtained at 6 radiation doses using 2 reconstruction algorithms and analyze its association with nodular size and density. METHODS: Seventy-four simulated GGNs (5, 8 and 10mm in diameter/-630 and -800 HU in density) were placed in a chest phantom in 14 nodular distribution patterns. Twelve sets of coronal images were obtained using CDT at 6 radiation doses: 120kV-10mA/20mA/80mA/160mA, 100kV-80mA and 80kV-320mA with and without iterative reconstruction (IR)...
January 19, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28102667/two-different-structures-of-the-oxygen-evolving-complex-in-the-same-polypeptide-frameworks-of-photosystem-ii
#11
Ayako Tanaka, Yoshimasa Fukushima, Nobuo Kamiya
The oxygen-evolving complex (OEC) forms the heart of photosystem II (PSII) in photosynthesis. The crystal structure of PSII from Thermosynechococcus vulcanus has been reported at a resolution of 1.9 Å and at an averaged X-ray dose of 0.43 MGy. The OEC structure is suggested to be partially reduced to Mn(II) by EXAFS and DFT compu-tational studies. Recently, the "radiation-damage-free" struc-tures have been published at 1.95 Å resolution using XFEL, but reports continued to appear that the OEC is reduced to the S0-state of the Kok cycle...
January 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28102510/influence-of-dose-reduction-and-iterative-reconstruction-on-ct-calcium-scores-a-multi-manufacturer-dynamic-phantom-study
#12
N R van der Werf, M J Willemink, T P Willems, M J W Greuter, T Leiner
To evaluate the influence of dose reduction in combination with iterative reconstruction (IR) on coronary calcium scores (CCS) in a dynamic phantom on state-of-the-art CT systems from different manufacturers. Calcified inserts in an anthropomorphic chest phantom were translated at 20 mm/s corresponding to heart rates between 60 and 75 bpm. The inserts were scanned five times with routinely used CCS protocols at reference dose and 40 and 80% dose reduction on four high-end CT systems. Filtered back projection (FBP) and increasing levels of IR were applied...
January 19, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28102497/regulated-partitioning-of-fixed-carbon-14-c-sodium-na-potassium-k-and-glycine-betaine-determined-salinity-stress-tolerance-of-gamma-irradiated-pigeonpea-cajanus-cajan-l-millsp
#13
Pankaj Kumar, Vasundhara Sharma, Chobhe Kapil Atmaram, Bhupinder Singh
Soil salinity is a major constraint that limits legume productivity. Pigeonpea is a salt sensitive crop. Seed gamma irradiation at a very low dose (2.5 Gy) is known to enhance seedling establishment, plant growth and yield of cereals and other crops. The present study conducted using two genetically diverse varieties of pigeonpea viz., Pusa-991 and Pusa-992 aimed at establishing the role of pre-sowing seed gamma irradiation at 0, 0.0025, 0.005, 0.01, 0.02, 0.05 and 0.1 kGy on plant growth, seed yield and seed quality under salt stress at 0, 80 and 100 mM NaCl (soil solution EC equivalent 1...
January 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28102439/reconstruction-of-radionuclide-intakes-for-the-residents-of-east-urals-radioactive-trace-1957-2011
#14
Evgenia I Tolstykh, Lyudmila M Peremyslova, Marina O Degteva, Bruce A Napier
The East Urals Radioactive Trace (EURT) was formed after a chemical explosion in the radioactive waste-storage facility of the Mayak Production Association in 1957 (Southern Urals, Russia) and resulted in an activity dispersion of 7.4 × 10(16) Bq into the atmosphere. Internal exposure due to ingestion of radionuclides with local foodstuffs was the main factor of public exposure at the EURT. The EURT cohort, combining residents of most contaminated settlements, was formed for epidemiological study at the Urals Research Center for Radiation Medicine, Russia (URCRM)...
January 19, 2017: Radiation and Environmental Biophysics
https://www.readbyqxmd.com/read/28102349/development-of-patient-specific-phantoms-for-verification-of-stereotactic-body-radiation-therapy-planning-in-patients-with-metallic-screw-fixation
#15
Dongryul Oh, Chae-Seon Hong, Sang Gyu Ju, Minkyu Kim, Bum Yong Koo, SungBack Choi, Hee Chul Park, Doo Ho Choi, Hongryull Pyo
A new technique for manufacturing a patient-specific dosimetric phantom using three-dimensional printing (PSDP_3DP) was developed, and its geometrical and dosimetric accuracy was analyzed. External body contours and structures of the spine and metallic fixation screws (MFS) were delineated from CT images of a patient with MFS who underwent stereotactic body radiation therapy for spine metastasis. Contours were converted into a STereoLithography file format using in-house program. A hollow, four-section PSDP was designed and manufactured using three types of 3DP to allow filling with a muscle-equivalent liquid and insertion of dosimeters...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28101739/inhalation-dose-due-to-radon-thoron-and-progenies-in-dwellings-of-a-hill-station
#16
R Sivakumar
The general public spends a major portion of their time in an indoor environment and hence receives a considerable amount of radiation. Knowledge about indoor radiation is important in order to arrive at the actual effective dose received by residents. The indoor radon, thoron, and progeny concentrations observed in the present study were found to vary with seasons of a given year. The highest and lowest indoor average radon, thoron, and progeny levels were observed during winter and summer seasons, respectively...
February 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28101417/investigation-of-terahertz-radiation-influence-on-rat-glial-cells
#17
Mariia Borovkova, Maria Serebriakova, Viacheslav Fedorov, Egor Sedykh, Vladimir Vaks, Alexander Lichutin, Alina Salnikova, Mikhail Khodzitsky
We studied an influence of continuous terahertz (THz) radiation (0.12 - 0.18 THz, average power density of 3.2 mW/cm(2)) on a rat glial cell line. A dose-dependent cytotoxic effect of THz radiation is demonstrated. After 1 minute of THz radiation exposure a relative number of apoptotic cells increased in 1.5 times, after 3 minutes it doubled. This result confirms the concept of biological hazard of intense THz radiation. Diagnostic applications of THz radiation can be restricted by the radiation power density and exposure time...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28100671/fast-neutron-survey-with-compact-plastic-scintillation-detectors
#18
Rhys M Preston, James R Tickner
With the rise of the Silicon Photomultiplier (SiPM), it is now practical to build compact scintillation detectors well suited to portable use. A prototype survey meter for fast-neutrons and gamma-rays, based around an EJ-299-34 plastic scintillator with SiPM readout, has been developed and tested. A custom digital pulse processor was used to perform pulse shape discrimination on-the-fly. Ambient dose equivalent H*(10) was calculated by means of two energy-dependent 'G-functions'. The sensitivity was calculated to be between 0...
January 17, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28100416/a-retrospective-analysis-of-the-clinical-effects-of-neoadjuvant-combination-therapy-with-full-dose-gemcitabine-and-radiation-therapy-in-patients-with-biliary-tract-cancer
#19
S Kobayashi, A Tomokuni, K Gotoh, H Takahashi, H Akita, S Marubashi, T Yamada, T Teshima, K Fukui, Y Fujiwara, M Sakon
PURPOSE: This study aims to evaluate survival and the objective response to neoadjuvant combination therapy with gemcitabine and radiation therapy in patients with biliary tract cancer. METHODS: The chemoradiation therapy regimen consisted of 3 cycles of full-dose gemcitabine (1000 mg/m(2) at days 1, 8, and 15, every 4 weeks) with 50-60 Gy radiation. We compared 27 patients who received neoadjuvant chemoradiation therapy and 79 patients who were treated without neoadjuvant therapy...
January 11, 2017: European Journal of Surgical Oncology
https://www.readbyqxmd.com/read/28100249/intraoperative-radiation-therapy-iort-in-soft-tissue-sarcoma
#20
REVIEW
Falk Roeder, Robert Krempien
Soft-tissue sarcoma (STS) represent a rare tumor entity, accounting for less than 1% of adult malignancies. The cornerstone of curative intent treatment is surgery with free margins, although the extent of the surgical approach has been subject to change in the last decades. Multimodal approaches usually including radiation therapy have replaced extensive surgical procedures in order to preserve functionality while maintaining adequate local control. However, the possibility to apply adequate radiation doses by external beam radiation therapy (EBRT) can be limited in some situation especially in case of directly adjacent organs at risk with low radiation tolerance...
January 19, 2017: Radiation Oncology
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