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radiation dosimetry

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https://www.readbyqxmd.com/read/28212111/direct-determination-of-k-q-for-farmer-type-ionization-chambers-in-a-clinical-scanned-carbon-ion-beam-using-water-calorimetry
#1
J-M Osinga-Blättermann, S Brons, S Greilich, O Jäkel, A Krauss
Until now, the dosimetry of carbon ions with ionization chambers has not reached the same level of accuracy as that of high-energy photons. This is mainly caused by the approximately threefold larger uncertainty of the k Q factor of ionization chambers, which, due to the lack of experimental data, is still derived by calculations. Measurements of absorbed dose to water, D w, by means of water calorimetry have now been performed in the entrance channel of a scanned 6 cm  ×  6 cm radiation field of 429 MeV/u carbon ions, allowing the direct calibration of ionization chambers and thus the experimental determination of k Q...
February 17, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28210770/the-reset-button-revisited-why-high-activity-131-i-therapy-of-advanced-differentiated-thyroid-cancer-after-dosimetry-is-advantageous-for-patients
#2
EDITORIAL
Frederik A Verburg, Markus Luster, Luca Giovanella, Michael Lassmann, Carlo Chiesa, Nicolas Chouin, Glenn Flux
No abstract text is available yet for this article.
February 16, 2017: European Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/28210202/mechanisms-and-effects-of-transcranial-direct-current-stimulation
#3
James Giordano, Marom Bikson, Emily S Kappenman, Vincent P Clark, H Branch Coslett, Michael R Hamblin, Roy Hamilton, Ryan Jankord, Walter J Kozumbo, R Andrew McKinley, Michael A Nitsche, J Patrick Reilly, Jessica Richardson, Rachel Wurzman, Edward Calabrese
The US Air Force Office of Scientific Research convened a meeting of researchers in the fields of neuroscience, psychology, engineering, and medicine to discuss most pressing issues facing ongoing research in the field of transcranial direct current stimulation (tDCS) and related techniques. In this study, we present opinions prepared by participants of the meeting, focusing on the most promising areas of research, immediate and future goals for the field, and the potential for hormesis theory to inform tDCS research...
January 2017: Dose-response: a Publication of International Hormesis Society
https://www.readbyqxmd.com/read/28209906/first-evaluation-of-pet-based-human-biodistribution-and-dosimetry-of-18-f-faza-a-tracer-for-imaging-tumor-hypoxia
#4
Savi Annarita, Elena Incerti, Federico Fallanca, Valentino Bettinardi, Francesca Rossetti, Cristina Monterisi, Antonia Compierchio, Giampiero Negri, Piero Zannini, Luigi Gianolli, Maria Picchio
Fluorine-18 labelled fluoroazomycinarabinoside ((18)F-FAZA) is a positron emission tomography (PET) biomarker for non-invasive identification of regional tumor hypoxia. Aim of the present Phase I study was to firstly evaluate in non-small cell lung cancer patients the human biodistribution and dosimetry of (18)F-FAZA. Methods: Five patients awaiting surgical resection after histologically proven or radiologically suspected non-small cell lung cancer were prospectively enrolled for the study. The patients underwent a PET/computed tomography (CT) study after the injection of 371±32 MBq of (18)F-FAZA...
February 16, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28205452/in-vivo-dosimetry-in-uk-external-beam-radiotherapy-current-and-future-usage
#5
Niall D MacDougall, Michael Graveling, Vibeke N Hansen, Kevin Brownsword, Andrew Morgan
OBJECTIVES: Towards Safer Radiotherapy (1) recommended that radiotherapy centres should have protocols in place for in vivo dosimetry (IVD) monitoring at the beginning of patient treatment courses. This report determines IVD implementation in the UK in 2014, the methods used and makes recommendations on future use. METHODS: Evidence from peer-reviewed journals was used in conjunction with the first survey of UK radiotherapy centres' IVD practice since the publication of TSRT...
February 16, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28204779/development-of-real-time-radiation-exposure-dosimetry-system-using-synthetic-ruby-for-interventional-radiology
#6
Yoshiyuki Hosokai, Kenki Matsumoto, Masataka Kozakai, Kaito Takahashi, Akihito Usui, Thet Pe Win, Kenzo Muroi, Haruo Saito
No abstract text is available yet for this article.
February 14, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28198880/proton-therapy-dosimetry-using-the-scintillation-of-the-silica-fibers
#7
Arash Darafsheh, Reza Taleei, Alireza Kassaee, Jarod C Finlay
We investigate the feasibility of proton therapy dose measurement by using scintillation of a bare silica glass fiber. The emission spectra of the optical fiber at various depths in tissue-mimicking phantoms, irradiated with proton beams of energies 100-225 MeV show two distinct peaks at 460 and 650 nm whose nature is connected with the silica point defects. Our experimental results and Monte Carlo simulation showed that the Čerenkov radiation cannot be responsible for such a phenomenon. We showed that the intensity of the peak at 650 nm correlates with the proton dose with a minimal effect of ionization quenching, while the intensity peak at 460 nm under-reports the radiation dose...
February 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28196607/development-of-a-model-web-based-system-to-support-a-statewide-quality-consortium-in-radiation-oncology
#8
Jean M Moran, Mary Feng, Lisa A Benedetti, Robin Marsh, Kent A Griffith, Martha M Matuszak, Michael Hess, Matthew McMullen, Jennifer H Fisher, Teamour Nurushev, Margaret Grubb, Stephen Gardner, Daniel Nielsen, Reshma Jagsi, James A Hayman, Lori J Pierce
PURPOSE: A database in which patient data are compiled allows analytic opportunities for continuous improvements in treatment quality and comparative effectiveness research. We describe the development of a novel, web-based system that supports the collection of complex radiation treatment planning information from centers that use diverse techniques, software, and hardware for radiation oncology care in a statewide quality collaborative, the Michigan Radiation Oncology Quality Consortium (MROQC)...
October 20, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28193241/present-state-and-issues-in-iort-physics
#9
REVIEW
Frank W Hensley
Literature was reviewed to assess the physical aspects governing the present and emerging technologies used in intraoperative radiation therapy (IORT). Three major technologies were identified: treatment with electrons, treatment with external generators of kV X-rays and electronic brachytherapy. Although also used in IORT, literature on brachytherapy with radioactive sources is not systematically reviewed since an extensive own body of specialized literature and reviews exists in this field. A comparison with radioactive sources is made in the use of balloon catheters for partial breast irradiation where these are applied in almost an identical applicator technique as used with kV X-ray sources...
January 27, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28192281/design-of-a-head-phantom-produced-on-a-3d-rapid-prototyping-printer-and-comparison-with-a-rando-and-3m-lucite-head-phantom-in-eye-dosimetry-applications
#10
Peter Homolka, Michael Figl, Andreas Wartak, Mathias Glanzer, Martina Duenkelmeyer, Azadeh Hojreh, Johann Hummel
An anthropomorphic head phantom including eye inserts allowing placement of TLDs 3 mm below the cornea has been produced on a 3D printer using photo-cured-acrylic resin to best allow tissue equivalence. Thus Hp(3) can be determined in radiological and interventional photon radiation fields. Eye doses and doses to the forehead have been compared to an Alderson RANDO head and a 3M Lucite skull phantom in terms of surface dose per incident air kerma for frontal irradiation since the commercial phantoms do not allow placement of TLDs 3 mm below the corneal surface...
February 13, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28191342/dose-response-curves-of-the-fdxr-and-rad51-genes-with-6-and-18-mv-beam-energies-in-human-peripheral-blood-lymphocytes
#11
Alihossein Saberi, Ehsan Khodamoradi, Mohammad Javad Tahmasebi Birgani, Manoochehr Makvandi, Bijan Noori
BACKGROUND: Rapid dose assessment using biological dosimetry methods is essential to increase the chance of survival of exposed individuals in radiation accidents. OBJECTIVES: We compared the expression levels of the FDXR and RAD51 genes at 6 and 18 MV beam energies in human peripheral blood lymphocytes. The results of our study can be used to analyze radiation energy in biological dosimetry. METHODS: For this in vitro experimental study, from 36 students in the medical physics and virology departments, seven voluntary, healthy, non-smoking male blood donors of Khuzestan ethnicity with no history of exposure to ionization radiation were selected using simple randomized sampling...
November 2016: Iranian Red Crescent Medical Journal
https://www.readbyqxmd.com/read/28188481/internal-exposure-to-neutron-activated-56-mn-dioxide-powder-in-wistar-rats-part%C3%A2-1-dosimetry
#12
Valeriy Stepanenko, Tolebay Rakhypbekov, Keiko Otani, Satoru Endo, Kenichi Satoh, Noriyuki Kawano, Kazuko Shichijo, Masahiro Nakashima, Toshihiro Takatsuji, Aya Sakaguchi, Hiroaki Kato, Yuichi Onda, Nariaki Fujimoto, Shin Toyoda, Hitoshi Sato, Altay Dyussupov, Nailya Chaizhunusova, Nurlan Sayakenov, Darkhan Uzbekov, Aisulu Saimova, Dariya Shabdarbaeva, Mazhin Skakov, Alexandr Vurim, Vyacheslav Gnyrya, Almas Azimkhanov, Alexander Kolbayenkov, Kasym Zhumadilov, Yankar Kairikhanova, Andrey Kaprin, Vsevolod Galkin, Sergey Ivanov, Timofey Kolyzhenkov, Aleksey Petukhov, Elena Yaskova, Irina Belukha, Artem Khailov, Valeriy Skvortsov, Alexander Ivannikov, Umukusum Akhmedova, Viktoria Bogacheva, Masaharu Hoshi
There were two sources of ionizing irradiation after the atomic bombings of Hiroshima and Nagasaki: (1) initial gamma-neutron irradiation at the moment of detonation and (2) residual radioactivity. Residual radioactivity consisted of two components: radioactive fallout containing fission products, including radioactive fissile materials from nuclear device, and neutron-activated radioisotopes from materials on the ground. The dosimetry systems DS86 and DS02 were mainly devoted to the assessment of initial radiation exposure to neutrons and gamma rays, while only brief considerations were given for the estimation of doses caused by residual radiation exposure...
February 10, 2017: Radiation and Environmental Biophysics
https://www.readbyqxmd.com/read/28183990/human-dosimetry-of-the-nmda-receptor-ligand-11-c-gmom
#13
Jasper van der Aart, Thalia F van der Doef, Paul Horstman, Marc C Huisman, Robert C Schuit, Arthur van Lingen, Albert D Windhorst, Bart N M van Berckel, Adriaan A Lammertsma
The methylguanadine derivative [(11)C]GMOM has been used successfully to quantify N-methyl-D-aspartate (NMDA) receptor binding in humans. The purpose of the present study was to estimate the [(11)C]GMOM radiation dose in healthy humans. Methods: Following [(11)C]GMOM injection, three female and two male subjects underwent 10 consecutive whole body PET scans in approximately 77 minutes. 7 source organs were defined manually, scaled to a gender specific reference, and residence times were calculated for input into OLINDA/EXM software...
February 9, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28181480/a-comparison-between-track-structure-condensed-history-monte-carlo-simulations-and-mird-cellular-s-values
#14
M A Tajik-Mansoury, H Rajabi, H Mozdarani
The S-value is a standard measure in cellular dosimetry. S-values are calculated by applying analytical methods or by Monte Carlo simulation. In Monte Carlo simulation, particles are either tracked individually event-by-event or close events are condensed and processed collectively in different steps. Both of these methods have been employed for estimation of cellular S-values, but there is no consistency between the published results. In the present paper, we used the Geant4-DNA track-structure physics model as the reference to estimate the cellular S-values...
March 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28179230/exposure-to-low-dose-computed-tomography-for-lung-cancer-screening-and-risk-of-cancer-secondary-analysis-of-trial-data-and-risk-benefit-analysis
#15
Cristiano Rampinelli, Paolo De Marco, Daniela Origgi, Patrick Maisonneuve, Monica Casiraghi, Giulia Veronesi, Lorenzo Spaggiari, Massimo Bellomi
Objective To estimate the cumulative radiation exposure and lifetime attributable risk of cancer incidence associated with lung cancer screening using annual low dose computed tomography (CT).Design Secondary analysis of data from a lung cancer screening trial and risk-benefit analysis.Setting 10 year, non-randomised, single centre, low dose CT, lung cancer screening trial (COSMOS study) which took place in Milan, Italy in 2004-15 (enrolment in 2004-05). Secondary analysis took place in 2015-16.Participants High risk asymptomatic smokers aged 50 and older, who were current or former smokers (≥20 pack years), and had no history of cancer in the previous five years...
February 8, 2017: BMJ: British Medical Journal
https://www.readbyqxmd.com/read/28169221/gaussian-plume-atmospheric-modelling-and-radiation-exposure-calculations-following-the-cremation-of-a-deceased-thyroid-cancer-patient-treated-with-iodine-131
#16
Phillipe J Calais
Shortly after treatment with 7200 MBq of (131)I, a thyroid cancer patient died and was subsequently cremated. Calculations of the atmospheric emissions of (131)I from the crematorium flue were performed using a standard atmospheric pollution Gaussian Plume Dispersal model. Estimates of whole-body and thyroid dose of those potentially exposed were made using OLINDA/EXM dosimetry software. Under the meteorological conditions prevalent at the time of the cremation, and depending on the actual release rate of the (131)I, the Western Australian legal limit of 3...
February 7, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/28168586/they-tamed-the-photon-early-days-of-radiation-dosimetry
#17
John R Patterson
This article is a tribute to the many physicists who tamed the photon in the service of mankind. Many received Nobel Prizes and other high awards. Several have units named after them. Some invented the equipment we use. Some sacrificed their lives before the hazards and benefits of radiation were fully understood. I discuss the progress over 120 years, both theoretical and technical, in the development of radiation protection regulations based on quantitative measurements and a consistent set of units, the gray and sievert...
February 6, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28164865/the-correction-of-time-and-temperature-effects-in-mr-based-3d-fricke-xylenol-orange-dosimetry
#18
Mattea L Welch, David Jaffray
<b>Purpose:</b> MR-based three-dimensional (3D) Fricke-xylenol orange (FXG) dosimeters can provide end-to-end quality assurance and validation protocols for pre-clinical radiation platforms. FXG dosimeters quantify ionizing irradiation using pre- and post-irradiation MR imaging methods that detect changes in spin-lattice relaxation rates (R<sub>1</sub> = T<sub>1</sub><sup>-1</sup>) caused by irradiation induced oxidation of Fe<sup>2+</sup>. Chemical changes in MR-based FXG dosimeters that occur over time and with changes in temperature can decrease dosimetric accuracy if they are not properly characterized and corrected...
February 6, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28159930/compared-planning-dosimetry-of-tomo-vmat-and-imrt-in-rectal-cancer-with-different-simulated-positions
#19
Jang-Chun Lin, Jo-Ting Tsai, Li-Jhen Chen, Ming-Hsien Li, Wei-Hsiu Liu
OBJECTIVES: To compare treatment plans for helical tomotherapy (TOMO), volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for locally advanced rectal cancer (LARC). MATERIALS AND METHODS: This retrospective study from December 2010 to June 2013 included 20 patients with LARC who received neoadjuvant concurrent chemoradiotherapy (CCRT) with radiation doses of greater than 50.4 Gy. Dosimetric quality was evaluated based on doses to organs at risk (OARs), including small bowel, urinary bladder and bilateral femoral head, over the same coverage of the clinical target volume (CTV)...
January 31, 2017: Oncotarget
https://www.readbyqxmd.com/read/28152195/a-2d-silicon-detector-array-for-quality-assurance-in-small-field-dosimetry-duo
#20
Khalsa Al Shukaili, Marco Petasecca, Matthew Newall, Anthony Espinoza, Vladimir L Perevertaylo, Stéphanie Corde, Michael Lerch, Anatoly B Rosenfeld
PURPOSE: Nowadays, there are many different applications that use small fields in radiotherapy treatments. The dosimetry of small radiation fields is not trivial due to the problems associated with lateral disequilibrium and source occlusion and requires reliable quality assurance (QA). Ideally such a QA tool should provide high spatial resolution, minimal beam perturbation and real time fast measurements. Many different types of silicon diode arrays are used for QA in radiotherapy; however, their application in small filed dosimetry is limited, in part, due to a lack of spatial resolution...
December 10, 2016: Medical Physics
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