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Dosimetry

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https://www.readbyqxmd.com/read/29351691/out-of-field-doses-in-children-treated-for-large-arteriovenous-malformations-using-hypofractionated-gamma-knife-radiosurgery-and-intensity-modulated-radiation-therapy
#1
Marijke De Saint-Hubert, Marija Majer, Hrvoje Hršak, Zdravko Heinrich, Željka Kneževic, Saveta Miljanic, Paulina Porwol, Liliana Stolarczyk, Filip Vanhavere, Roger M Harrison
The purpose of this study was to measure out-of-field organ doses in two anthropomorphic child phantoms for the treatment of large brain arteriovenous malformations (AVMs) using hypofractionated gamma knife (GK) radiosurgery and to compare these with an alternative treatment using intensity-modulated radiation therapy (IMRT). Target volume was identical in size and shape in all cases. Radiophotoluminescent (RPL), thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters were used for out-of-field dosimetry during GK treatment and a good agreement within 1-2% between results was shown...
January 17, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29351653/calibration-of-gafchromic-ebt3-film-for-dosimetry-of-scanning-proton-pencil-beam-pbs
#2
D Krzempek, G Mianowska, N Bassler, L Stolarczyk, R Kopec, B Sas-Korczynska, P Olko
Gafchromic EBT3 films are applied in proton radiotherapy for 2D dose mapping because they demonstrate spatial resolution well below 1 mm. However, the film response must be corrected in order to reach the accuracy of dose measurements required for the clinical use. The in-house developed AnalyseGafchromic software allows to analyze and correct the measured response using triple channel dose calibration, statistical scan-to-scan fluctuations as well as experimentally determined dose and LET dependence. Finally, the optimized protocol for evaluation of response of Gafchromic EBT3 films was applied to determine 30 × 40 cm2 dose profiles of the scanning therapy unit at the Cyclotron Centre Bronowice, CCB in Krakow, Poland...
January 17, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29351645/dosimetry-during-percutaneous-coronary-interventions-of-chronic-total-occlusions
#3
Jérémie Dabin, Joren Maeremans, Danielle Berus, Werner Schoonjans, Giulia Tamborino, Jo Dens, Peter Kayaert
Percutaneous coronary interventions (PCI) of coronary chronic total occlusions (CTO) increase the risk of high radiation exposure for both the patient and the cardiologist. This study evaluated the maximum dose to the patients' skin (MSD) and the exposure of the cardiologists during CTO-PCI. Moreover, the efficiency of radioprotective drapes to reduce cardiologist exposure was assessed. Patient dose was measured during 31 procedures; dose to the cardiologist's extremities were measured during 65 procedures, among which 31 were performed with radioprotective drapes...
January 17, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29350236/dose-optimization-of-total-or-partial-skin-electron-irradiation-by-thermoluminescent-dosimetry
#4
Lars Schüttrumpf, Klement Neumaier, Cornelius Maihoefer, Maximilian Niyazi, Ute Ganswindt, Minglun Li, Peter Lang, Michael Reiner, Claus Belka, Stefanie Corradini
BACKGROUND: Due to the complex surface of the human body, total or partial skin irradiation using large electron fields is challenging. The aim of the present study was to quantify the magnitude of dose optimization required after the application of standard fields. METHODS: Total skin electron irradiation (TSEI) was applied using the Stanford technique with six dual-fields. Patients presenting with localized lesions were treated with partial skin electron irradiation (PSEI) using large electron fields, which were individually adapted...
January 19, 2018: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/29350197/a-three-dimensional-correction-method-for-predicting-the-readings-of-a-pinpoint-chamber-on-the-cyberknife-sup-%C3%A2-sup-m6%C3%A2-machine
#5
Yongqian Zhang, Edward Brandner, Cihat Ozhasoglu, Ron Lalonde, Dwight E Heron, M Saiful Huq
The use of small fields in radiation therapy techniques has increased substantially in particular in stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). However, as field size reduces further still, the response of the detector changes more rapidly with field size, and the effects of measurement uncertainties become increasingly significant. This work presents a novel 3D dose volume-to-point correction method to predict the readings of a 0.015cc PinPoint chamber (PTW 31014) for both small static-fields and composite-field dosimetry formed by fixed cones on the CyberKnife® M6™ machine...
January 19, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29350196/estimation-and-correction-of-produced-light-from-prompt-gamma-photons-on-luminescence-imaging-of-water-for-proton-therapy-dosimetry
#6
Takuya Yabe, Masataka Komori, Toshiyuki Toshito, Mitsutaka Yamaguchi, Naoki Kawachi, Seiichi Yamamoto
Although the luminescence images of water during proton-beam irradiation using a cooled charge-coupled device (CCD) camera showed almost the same ranges of proton beams as those measured by an ionization chamber, the depth profiles showed lower Bragg peak intensities than those measured by an ionization chamber. In addition, a broad optical baseline signal was observed in depths that exceed the depth of Bragg peak. We hypothesize that this broad baseline signal originates from interaction of proton-induced prompt gamma photons with water...
January 19, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29348735/dosimetric-evaluation-of-image-based-brachytherapy-using-tandem-ovoid-and-tandem-ring-applicators
#7
Ramya Rangarajan
Aim: The aim of the study is to evaluate the differences in dosimetry between tandem-ovoid and tandem-ring gynaecologic brachytherapy applicators in image based brachytherapy. Background: Traditionally, tandem ovoid applicators were used to deliver dose to tumor in intracavitary brachytherapy. Tandem-ring, tandem-cylinder and hybrid intracavitary, interstitial applicators are also used nowadays in cervical cancer brachytherapy. Methods and materials: 100 CT datasets of cervical cancer patients (stage IB2 - IIIB) receiving HDR application (50 tandem-ovoid and 50 tandem-ring) were studied...
January 2018: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/29348315/whole-body-biodistribution-and-dosimetry-of-the-dopamine-transporter-radioligand-18f-fe-pe2i-in-human-subjects
#8
Helena Lizana, Lennart Johansson, Jan E Axelsson, Anne Larsson Strömvall, Mattias Ögren, Jan Linder, Christer Halldin, Andrea Varrone, Susanna Jakobson Mo
18F-(E)-N-(3-iodoprop-2-enyl)-2β-carbofluoroethoxy-3β-(4'-methyl-phenyl) nortropane (18F-FE-PE2I) was recently developed and has shown adequate affinity and high selectivity for the dopamine transporter (DAT). Previous studies have shown promising results for 18F-FE-PE2I as a suitable radioligand for DAT-imaging. In this study, we investigate the whole body biodistribution and dosimetry of 18F-FE-PE2I in healthy volunteers to support the utility of it as a suitable positron emission tomography (PET) imaging agent for the DAT...
January 18, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/29345977/targeted-and-nontargeted-%C3%AE-particle-therapies
#9
Michael R McDevitt, George Sgouros, Stavroula Sofou
α-Particle irradiation of cancerous tissue is increasingly recognized as a potent therapeutic option. We briefly review the physics, radiobiology, and dosimetry of α-particle emitters, as well as the distinguishing features that make them unique for radiopharmaceutical therapy. We also review the emerging clinical role of α-particle therapy in managing cancer and recent studies on in vitro and preclinical α-particle therapy delivered by antibodies, other small molecules, and nanometer-sized particles. In addition to their unique radiopharmaceutical characteristics, the increased availability and improved radiochemistry of α-particle radionuclides have contributed to the growing recent interest in α-particle radiotherapy...
January 18, 2018: Annual Review of Biomedical Engineering
https://www.readbyqxmd.com/read/29344782/accuracy-and-efficiency-of-published-film-dosimetry-techniques-using-a-flat-bed-scanner-and-ebt3-film
#10
E Spelleken, S B Crowe, B Sutherland, C Challens, T Kairn
Gafchromic EBT3 film is widely used for patient specific quality assurance of complex treatment plans. Film dosimetry techniques commonly involve the use of transmission scanning to produce TIFF files, which are analysed using a non-linear calibration relationship between the dose and red channel net optical density (netOD). Numerous film calibration techniques featured in the literature have not been independently verified or evaluated. A range of previously published film dosimetry techniques were re-evaluated, to identify whether these methods produce better results than the commonly-used non-linear, netOD method...
January 17, 2018: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/29342297/an-exact-goodness-of-fit-test-based-on-the-occupancy-problems-to-study-zero-inflation-and-zero-deflation-in-biological-dosimetry-data
#11
Amanda Fernández-Fontelo, Pedro Puig, Elizabeth A Ainsbury, Manuel Higueras
The goal in biological dosimetry is to estimate the dose of radiation that a suspected irradiated individual has received. For that, the analysis of aberrations (most commonly dicentric chromosome aberrations) in scored cells is performed and dose response calibration curves are built. In whole body irradiation (WBI) with X- and gamma-rays, the number of aberrations in samples is properly described by the Poisson distribution, although in partial body irradiation (PBI) the excess of zeros provided by the non-irradiated cells leads, for instance, to the Zero-Inflated Poisson distribution...
January 12, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29342278/dosimetry-of-adult-and-pediatric-patients-for-common-digital-radiography-examinations
#12
Bhupendra Singh Rana, Sanjeev Kumar, Inderjeet Singh Sandhu, Narinder Paul Singh
The present work reports dosimetry data on adult and pediatric patients for some common radiographic examinations during the standard hospital routine. The measurements are the part of quality assurance program to determine radiation exposures to patients in these examinations. The entrance skin doses (ESDs) of the patients were measured from 2451 projection for 12 diagnostic examinations in digital radiography (DR). The ESDs in adult patient were measured using thermoluminescence dosemeters placed on the skin of the patient...
January 12, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29342223/development-of-a-job-exposure-matrix-for-noise-in-the-swedish-soft-tissue-paper-industry
#13
Richard Lee Neitzel, Marianne Andersson, Helena Eriksson, Kjell Torén, Eva Andersson
Objectives: Noise exposure is a common occupational hazard, but has not been sufficiently characterized in paper mills. We developed a job-exposure matrix (JEM) for noise exposure for use in estimating exposures among Swedish soft tissue paper mill workers. Methods: We used a combination of area and personal dosimetry noise exposure measurements made at four soft tissue paper mills by industry and research staff between 1977 and 2013 to estimate noise exposures by department, location, and job title...
December 16, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/29341541/radiotherapy-fiber-dosimeter-probes-based-on-silver-only-coated-hollow-glass-waveguides
#14
Arash Darafsheh, Jeffrey E Melzer, James A Harrington, Alireza Kassaee, Jarod C Finlay
Manifestation of Čerenkov radiation as a contaminating signal is a significant issue in radiation therapy dose measurement by fiber-coupled scintillator dosimeters. To enhance the scintillation signal transmission while minimizing Čerenkov radiation contamination, we designed a fiber probe using a silver-only coated hollow waveguide (HWG). The HWG with scintillator inserted in its tip, embedded in tissue-mimicking phantoms, was irradiated with clinical electron and photon beams generated by a medical linear accelerator...
January 2018: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29340629/development-of-a-set-of-mesh-based-and-age-dependent-chinese-phantoms-and-application-for-ct-dose-calculations
#15
Yifei Pi, Tianyu Liu, X George Xu
Phantoms for organ dose calculations are essential in radiation protection dosimetry. This article describes the development of a set of mesh-based and age-dependent phantoms for Chinese populations using reference data recommended by the Chinese government and by the International Atomic Energy Agency (IAEA). Existing mesh-based RPI adult male (RPI-AM) and RPI adult female (RPI-AF) phantoms were deformed to form new phantoms according to anatomical data for the height and weight of Chinese individuals of 5 years old male, 5 years old female, 10 years old male, 10 years old female,15 years old male, 15 years old female, adult male and adult female-named USTC-5 M, USTC-5F, USTC-10M, USTC-10F, USTC-15M, USTC-15F, USTC-AM and USTC-AF, respectively...
January 11, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29339573/-sup-18-sup-f-choline-pet-ct-for-parathyroid-scintigraphy-significantly-lower-radiation-exposure-of-patients-in-comparison-to-conventional-nuclear-medicine-imaging-approaches
#16
Sebastijan Rep, Marko Hocevar, Janja Vaupotič, Urban Zdesar, Katja Zaletel, Luka Lezaic
Parathyroid subtraction scintigraphy is the most commonly used imaging method for localization of hyperfunctioning parathyroid glands (HPG) in primary hyperparathyroidism, a common endocrine disorder. Hybrid (SPECT/CT) imaging with 99mTc-sestaMIBI (MIBI) at an early and delayed phase (dual-phase imaging) may be the most accurate conventional imaging approach, but includes additional radiation exposure due to added CT imaging. Recently, 18F-choline (FCH) PET/CT was introduced for HPG imaging, which can also be performed using the dual-phase approach...
January 17, 2018: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/29339047/the-impact-of-semilateral-decubitus-position-on-the-dose-volume-parameters-of-the-heart-and-lung-for-left-sided-breast-cancer-patients-a-comparative-dosimetric-study
#17
Azza Helal, Mohamed Farouk, Sherief H Gamie, Mahran Abdo, Lila Mosa, Amr Abdul Aziz
PURPOSE: When treating breast cancer with radiation therapy, the impact of treatment position on heart and lung dose-volume parameters (DVPs) is largely dependent on the maximal heart distance (MHD) and central lung distance (CLD). We evaluate how much heart and lung sparing can be achieved using the semilateral decubitus (SLD) position without and with breath hold compared with the standard supine position for left-sided breast cancer patients. A secondary aim was to investigate the impact of MHD and CLD on heart and lung DVPs...
December 2, 2017: Practical Radiation Oncology
https://www.readbyqxmd.com/read/29336934/determination-of-recombination-and-polarity-correction-factors-ks-and-kp-for-small-cylindrical-ionization-chambers-ptw-31021-and-ptw-31022-in-pulsed-filtered-and-unfiltered-beams
#18
Gregor Bruggmoser, Rainer Saum, Rafael Kranzer
The aim of this technical communication is to provide correction factors for recombination and polarity effect for two new ionization chambers PTW PinPoint 3D (type 31022) and PTW Semiflex 3D (type 31021). The correction factors provided are for the (based on the) German DIN 6800-2 dosimetry protocol and the AAPM TG51 protocol. The measurements were made in filtered and unfiltered high-energy photon beams in a water equivalent phantom at maximum depth of the PDD and a field size on the surface of 10cm×10cm...
January 11, 2018: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/29333465/in-vivo-exposure-effects-of-99mtc-methoxyisobutylisonitrile-on-the-fdxr-and-xpa-genes-expression-in-human-peripheral-blood-lymphocytes
#19
Mohammad Taghi Bahreyni-Toossi, Habibeh Vosoughi, Hosein Azimian, Abdul Rahim Rezaei, Mehdi Momennezhad
Objectives: In recent years, the application of radiopharmaceuticals in nuclear medicine has increased substantially. Following the diagnostic procedures performed in nuclear medicine departments, such as myocardial perfusion imaging, patients generally receive considerable doses of radiation. Normally, radiation-induced DNA damages are expected following exposure to a low-dose ionizing radiation. In order to detect molecular changes, high-sensitivity techniques must be utilized. The aim of this study was to assess the effect of a low-dose (below 10 mSv) gamma ray on gene expression using quantitative real-time polymerase chain reaction (qRT-PCR)...
2018: Asia Oceania Journal of Nuclear Medicine & Biology
https://www.readbyqxmd.com/read/29333127/quality-assurance-procedures-based-on-dosimetric-gamma-analysis-as-a-fast-reliable-tool-for-commissioning-brachytherapy-treatment-planning-systems
#20
Grzegorz Zwierzchowski, Grzegorz Bieleda, Janusz Skowronek
Background: Fast and easily repeatable methods for commissioning procedures for brachytherapy (BT) treatment planning systems (TPS) are needed. Radiochromic film dosimetry with gamma analysis is widely used in external beam quality assurance (QA) procedures and planar film dosimetry is also increasingly used for verification of the dose distribution in BT applications. Using the gamma analysis method for comparing calculated and measured dose data could be used for commissioning procedures of the newly developed TG-186 and MBDCA calculation algorithms...
December 2017: Radiology and Oncology
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