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Radiation dose measurements

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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/29351645/dosimetry-during-percutaneous-coronary-interventions-of-chronic-total-occlusions
#2
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/29351567/whole-thorax-irradiation-of-non-human-primates-induces-persistent-nuclear-damage-and-gene-expression-changes-in-peripheral-blood-cells
#3
Shanaz A Ghandhi, Helen C Turner, Igor Shuryak, Gregory O Dugan, J Daniel Bourland, John D Olson, Janet A Tooze, Shad R Morton, Ines Batinic-Haberle, J Mark Cline, Sally A Amundson
We investigated the cytogenetic and gene expression responses of peripheral blood cells of non-human primates (NHP, Macaca mulatta) that were whole-thorax irradiated with a single dose of 10 Gy. In this model, partial irradiation of NHPs in the thoracic region (Whole Thorax Lung Irradiation, WTLI) allows the study of late radiation-induced lung injury, while avoiding acute radiation syndromes related to hematopoietic and gastrointestinal injury. A transient drop in circulating lymphocytes and platelets was seen by 9 days, followed by elevations in respiratory rate, circulating neutrophils, lymphocytes, and monocytes at 60-100 days, corresponding to computed tomography (CT) and histologic evidence of pneumonitis, and elective euthanasia of four animals...
2018: PloS One
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
#4
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/29349358/95gtc-and-96gtc-as-alternatives-to-medical-radioisotope-99mtc
#5
Takehito Hayakawa, Yuichi Hatsukawa, Toru Tanimori
We studied 95gTc and 96gTc as alternatives to the medical radioisotope 99mTc. 96gTc (95gTc) can be produced by (p, n) reactions on an enriched 96Mo (95Mo) target with a proton beam provided by a compact accelerator such as a medical cyclotron that generate radioisotopes for positron emission tomography (PET). The γ-rays are measured with an electron-tracking Compton camera (ETCC). We calculated the relative intensities of the γ-rays from 95gTc and 96gTc. The calculated γ-ray intensity of a 96gTc (95gTc) nucleus is as high as 63% (70%) of that of a 99mTc nucleus...
January 2018: Heliyon
https://www.readbyqxmd.com/read/29346670/scoping-analysis-of-material-activation-at-a-boron-neutron-capture-therapy-facility-based-on-the-be-p-xn-reaction-with-30-mev-protons
#6
Bo-Lun Lai, Rong-Jiun Sheu
Material activation assessment of a proposed accelerator-based boron neutron capture therapy facility was performed using the FLUKA Monte Carlo code to quantify the magnitude of the problem in terms of the isotope inventories, induced activities, and residual dose rates. Two simplified operation scenarios were considered: a 30-min proton bombardment to simulate a typical session of patient treatment and a long-term 1 year continuous operation to estimate the accumulation of long-lived radionuclides. Following the generation and transport of decay radiation, the space- and time-dependent inventories of induced radionuclides in materials and residual dose rates after shutdown were obtained...
January 16, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29346552/safety-profile-of-near-zero-fluoroscopy-atrial-fibrillation-ablation-with-non-fluoroscopic-catheter-visualization-experience-from-1000-consecutive-procedures
#7
Philipp Sommer, Livio Bertagnolli, Simon Kircher, Arash Arya, Andreas Bollmann, Sergio Richter, Sascha Rolf, Gerhard Hindricks
Aims: Efforts to reduce radiation exposure during catheter ablation procedures have included the use of various technological measures. Significant results have been achieved to the point where near lead-free procedures in routine clinical practice has become a realistic goal. The integration of MediGuide technology [non-fluoroscopic catheter visualization technology (NFCV)] and three-dimensional electroanatomical mapping is one of the methods developed in response to radiation reduction initiatives...
January 16, 2018: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29346192/image-quality-overall-evaluability-and-effective-radiation-dose-of-coronary-computed-tomography-angiography-with-prospective-electrocardiographic-triggering-plus-intracycle-motion-correction-algorithm-in-patients-with-a-heart-rate-over-65-beats-per-minute
#8
Gianluca Pontone, Giuseppe Muscogiuri, Andrea Baggiano, Daniele Andreini, Andrea I Guaricci, Marco Guglielmo, Fabio Fazzari, Saima Mushtaq, Edoardo Conte, Andrea Annoni, Alberto Formenti, Elisabetta Mancini, Massimo Verdecchia, Laura Fusini, Lorenzo Bonfanti, Elisa Consiglio, Mark G Rabbat, Antonio L Bartorelli, Mauro Pepi
PURPOSE: Recently, a new intracycle motion correction algorithm (MCA) was introduced to reduce motion artifacts from heart rate (HR) in coronary computed tomography angiography (cCTA). The aim of the study was to evaluate the image quality, overall evaluability, and effective radiation dose (ED) of cCTA with prospective electrocardiographic (ECG) triggering plus MCA as compared with standard protocol with retrospective ECG triggering in patients with HR≥65 bpm. MATERIALS AND METHODS: One hundred consecutive patients (67±10 y) scheduled for cCTA with 65<HR<80 bpm were retrospectively analyzed...
January 16, 2018: Journal of Thoracic Imaging
https://www.readbyqxmd.com/read/29346028/biophysics-model-of-heavy-ion-degradation-of-neuron-morphology-in-mouse-hippocampal-granular-cell-layer-neurons
#9
Murat Alp, Francis A Cucinotta
Exposure to heavy-ion radiation during cancer treatment or space travel may cause cognitive detriments that have been associated with changes in neuron morphology and plasticity. Observations in mice of reduced neuronal dendritic complexity have revealed a dependence on radiation quality and absorbed dose, suggesting that microscopic energy deposition plays an important role. In this work we used morphological data for mouse dentate granular cell layer (GCL) neurons and a stochastic model of particle track structure and microscopic energy deposition (ED) to develop a predictive model of high-charge and energy (HZE) particle-induced morphological changes to the complex structures of dendritic arbors...
January 18, 2018: Radiation Research
https://www.readbyqxmd.com/read/29344955/development-of-an-advanced-two-dimensional-microdosimetric-detector-based-on-thick-gas-electron-multipliers
#10
Sahar Darvish-Molla, William V Prestwich, Soo Hyun Byun
PURPOSE: The THick Gas Electron Multiplier (THGEM) based tissue-equivalent proportional counter (TEPC) has been proven to be useful for microdosimetry due to its flexibility in varying the gaseous sensitive volume and achieving high multiplication gain. Aiming at measuring the spatial distribution of radiation dose for mixed neutron-gamma fields, an advanced two-dimensional (2-D) THGEM TEPC was designed and constructed at McMaster University which will enable us to overcome the operational limitation of the classical TEPCs, particularly for high dose rate fields...
January 18, 2018: Medical Physics
https://www.readbyqxmd.com/read/29344710/radiation-doses-to-operators-in-hepatobiliary-interventional-procedures
#11
Sarah Degiorgio, Roberta Gerasia, Ferdinanda Liotta, Luigi Maruzzelli, Kelvin Cortis, Roberto Miraglia, Angelo Luca
PURPOSE: The primary aim of this study is to provide a summary of operators' radiation doses during hepatobiliary fluoroscopic guided procedures. In addition, patient dose in these procedures was also documented. MATERIALS AND METHODS: A total of 283 transarterial chemoembolisation (TACE) and 302 biliary procedures, including 52 percutaneous transhepatic cholangiogram (PTC), 36 bilioplasty and 214 biliary catheter changes (BCC) performed over 14 months, were included...
January 17, 2018: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/29343841/microdosimetric-modeling-of-biological-effectiveness-for-boron-neutron-capture-therapy-considering-intra-and-intercellular-heterogeneity-in-10b-distribution
#12
Tatsuhiko Sato, Shin-Ichiro Masunaga, Hiroaki Kumada, Nobuyuki Hamada
We here propose a new model for estimating the biological effectiveness for boron neutron capture therapy (BNCT) considering intra- and intercellular heterogeneity in 10B distribution. The new model was developed from our previously established stochastic microdosimetric kinetic model that determines the surviving fraction of cells irradiated with any radiations. In the model, the probability density of the absorbed doses in microscopic scales is the fundamental physical index for characterizing the radiation fields...
January 17, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29343026/-applied-research-of-quadri-low-combined-with-automatic-tube-current-modulation-and-iterative-model-reconstruction-technology-in-head-and-neck-ct-angiography
#13
W Cai, C H Hu, X M Wang, S Hu, J Bao, J P Gong, G H Fan, W Zhang, D Shi, M H Qian
Objective: To investigate the feasibility of low tube voltage, low contrast medium concentration, injection rate and volume (quadri-low) combined with automatic tube current modulation (ATCM) and iterative model reconstruction (IMR) technology in head and neck CT angiography (CTA). Methods: A total of 70 patients whose body mass index (BMI)<25 kg/m(2) underwent head and neck CTA and digital subtraction angiography (DSA) from January to July 2017 were enrolled in this prospective study. According to random number table, patients were divided into two groups: group A (n=35) was scanned according to the protocol of 120 kV, 150 mAs, 50 ml and 5 ml/s iopromide (370 mg/ml) and filtered back projection (FBP) reconstruction; group B (n=35) was scanned with 80 kV, ATCM with mean tube current of 100 mAs, 30 ml and 3 ml/s iohexol (300 mg/ml) and IMR; the other parameters kept consistent between the two groups...
January 2, 2018: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/29342941/development-of-optical-fiber-based-measurement-system-for-the-verification-of-entrance-dose-map-in-pencil-beam-scanning-proton-beam
#14
Jaeman Son, Se Byeong Lee, Youngkyung Lim, Sung Yong Park, Kwanho Cho, Myonggeun Yoon, Dongho Shin
This study describes the development of a beam monitoring system for the verification of entrance dose map in pencil beam scanning (PBS) proton therapy based on fiber optic radiation sensors (FORS) and the validation of this system through a feasibility study. The beam monitoring system consisted of 128 optical fibers optically coupled to photo-multiplier tubes. The performance of the beam monitoring system based on FORS was verified by comparing 2D dose maps of square-shaped fields of various sizes, which were obtained using conventional dosimeters such as MatriXX and EBT3 film, with those measured using FORS...
January 15, 2018: Sensors
https://www.readbyqxmd.com/read/29342302/determination-of-the-appropriate-physical-density-of-internal-metallic-ports-in-temporary-tissue-expanders-for-the-treatment-planning-of-post-mastectomy-radiation-therapy
#15
Norifumi Mizuno, Haruna Takahashi, Jiro Kawamori, Naoki Nakamura, Mami Ogita, Shogo Hatanaka, Ryouhei Yamauchi, Masatsugu Hariu, Kenji Sekiguchi
Some patients undergoing breast reconstruction require post-mastectomy radiation therapy, but the metallic ports used in temporary tissue expanders attenuate the X-rays. In this study, we evaluated by the film method, the attenuation of 4 MV and 6 MV X-rays after passing through a metallic port, with the aim of identifying a useful method for determining the appropriate density to use in the radiation treatment planning system (RTPS), taking into account the distance between the metallic port and the targets...
January 12, 2018: Journal of Radiation Research
https://www.readbyqxmd.com/read/29342278/dosimetry-of-adult-and-pediatric-patients-for-common-digital-radiography-examinations
#16
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/29341541/radiotherapy-fiber-dosimeter-probes-based-on-silver-only-coated-hollow-glass-waveguides
#17
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/29340779/dose-image-quality-and-spine-modeling-assessment-of-biplanar-eos-micro-dose-radiographs-for-the-follow-up-of-in-brace-adolescent-idiopathic-scoliosis-patients
#18
Baptiste Morel, Sonia Moueddeb, Eleonore Blondiaux, Stephen Richard, Manon Bachy, Raphael Vialle, Hubert Ducou Le Pointe
PURPOSE: The aim of this study was to compare the radiation dose, image quality and 3D spine parameter measurements of EOS low-dose and micro-dose protocols for in-brace adolescent idiopathic scoliosis (AIS) patients. METHODS: We prospectively included 25 consecutive patients (20 females, 5 males) followed for AIS and undergoing brace treatment. The mean age was 12 years (SD 2 years, range 8-15 years). For each patient, in-brace biplanar EOS radiographs were acquired in a standing position using both the conventional low-dose and micro-dose protocols...
January 16, 2018: European Spine Journal
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
#19
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/29339540/radio-resistant-cervical-cancers-are-sensitive-to-inhibition-of-glycolysis-and-redox-metabolism
#20
Ramachandran Rashmi, Xiaojing Huang, John M Floberg, Adnan Elhammali, Michael L McCormick, Gary J Patti, Douglas R Spitz, Julie K Schwarz
Highly glycolytic cervical cancers largely resist treatment by cisplatin and co-administered pelvic irradiation as the present standard of care. In this study, we investigated the effects of inhibiting glycolysis and thiol redox metabolism to evaluate them as alternate treatment strategies in these cancers. In a panel of multiple cervical cancer cell lines, we evaluated sensitivity to inhibition of glycolysis (2-DG) with or without simultaneous inhibition of glutathione and thioredoxin metabolism (BSO/AUR)...
January 16, 2018: Cancer Research
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