keyword
MENU ▼
Read by QxMD icon Read
search

Proton Beam

keyword
https://www.readbyqxmd.com/read/29149320/organic-scintillator-for-real-time-neutron-dosimetry
#1
Kyle A Beyer, Angela Di Fulvio, Liliana Stolarczyk, Wiktor Parol, Natalia Mojzeszek, Renata Kopéc, Shaun D Clarke, Sara A Pozzi
We developed a radiation detector based on an organic scintillator for spectrometry and dosimetry of out-of-field secondary neutrons from clinical proton beams. The detector consists of an EJ-299-34 crystalline organic scintillator, coupled by fiber optic cable to a silicon photomultiplier (SiPM). Proof of concept measurements were taken with 137Cs and 252Cf, and corresponding simulations were performed in MCNPX-PoliMi. Despite its small size, the detector is able to discriminate between neutron and gamma-rays via pulse shape discrimination...
November 15, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29148575/effects-of-spot-parameters-in-pencil-beam-scanning-treatment-planning
#2
Aafke Christine Kraan, Nicolas Depauw, Ben Clasie, Marina Giunta, Tom Madden, Hanne M Kooy
BACKGROUND: Spot size σ (in-air at isocenter), inter-spot spacing d, and spot charge q influence dose delivery efficiency and plan quality in Intensity Modulated Proton Therapy (IMPT) treatment planning. The choice and range of parameters varies among different manufacturers. The goal of this work is to demonstrate the influence of the spot parameters on dose quality and delivery in IMPT treatment plans, to show their interdependence, and to make practitioners aware of the spot parameter values for a certain facility...
November 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/29139207/patient-reported-outcomes-of-slow-single-arc-rotation-do-we-need-rotating-gantries
#3
Brendan Whelan, Miriam Welgampola, Leigh McGarvie, Kuldeep Makhija, Robin M Turner, Lois Holloway, Ilana Feain, Michael Jackson, Michael Barton, Paul Keall
INTRODUCTION: Patient rotation could greatly simplify radiation therapy delivery, with particularly important ramifications for fixed beam treatment with protons, heavy ions, MRI-Linacs, and low cost Linacs. Patient tolerance is often cited as a barrier to widespread implementation to patient rotation; however, no quantitative data addressing this issue exists. In this study, patient reported experiences of slow, single arc rotation in upright (sitting) and lying orientations are reported...
November 15, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/29136081/imaging-the-dynamics-of-ion-molecule-reactions
#4
REVIEW
Eduardo Carrascosa, Jennifer Meyer, Roland Wester
A range of ion-molecule reactions have been studied in the last years using the crossed-beam ion imaging technique, from charge transfer and proton transfer to nucleophilic substitution and elimination. This review presents the detailed insights that have been gained with respect to the dynamics of both cation-molecule and anion-molecule reactions studied with this method. In particular, we show the recent progress that has been achieved to understand the atomistic energetics and dynamics of ion-molecule reactions, such as the effects of vibrational quantum states, the formation of carbon-carbon bonds, and the competition between nucleophilic substitution and elimination...
November 14, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/29135712/limbal-stem-cell-preservation-during-proton-beam-irradiation-for-diffuse-iris-melanoma
#5
Paul T Finger, Wolfgang A G Sauerwein
No abstract text is available yet for this article.
November 13, 2017: Cornea
https://www.readbyqxmd.com/read/29134674/experimental-validation-of-two-dual-energy-ct-methods-for-proton-therapy-using-heterogeneous-tissue-samples
#6
Esther Bär, Arthur Lalonde, Rongxiao Zhang, Kyung-Wook Jee, Kai Yang, Gregory Sharp, Bob Liu, Gary Royle, Hugo Bouchard, Hsiao-Ming Lu
PURPOSE: The purpose of this work is to evaluate the performance of dual-energy CT (DECT) for determining proton stopping power ratios (SPRs) in an experimental environment and to demonstrate its potential advantages over conventional single-energy CT (SECT) in clinical conditions. METHODS: Water equivalent range (WER) measurements of 12 tissue-equivalent plastic materials and 12 fresh animal tissue samples are performed in a 195 MeV broad proton beam using the dose extinction method...
November 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29131351/ion-recombination-and-polarity-correction-factors-for-a-plane-parallel-ionization-chamber-in-a-proton-scanning-beam
#7
Małgorzata Liszka, Liliana Stolarczyk, Magdalena Kłodowska, Anna Kozera, Dawid Krzempek, Natalia Mojżeszek, Anna Pędracka, Michael Patrick Russell Waligórski, Paweł Olko
PURPOSE: To evaluate the effect on charge collection in the ionization chamber (IC) in proton pencil beam scanning (PBS), where the local dose-rate may exceed the dose rates encountered in conventional MV therapy by up to 3 orders of magnitude. METHODS: We measured values of the ion recombination (ks ) and polarity (kpol ) correction factors in water, for a plane-parallel Markus TM23343 IC, using the cyclotron-based Proteus-235 therapy system with an active proton PBS of energies 30-230 MeV...
November 13, 2017: Medical Physics
https://www.readbyqxmd.com/read/29129096/eras-tubeless-michael-haddock-the-past-and-future-of-proton-beam
#8
Bella Poon, Helen Seliman
No abstract text is available yet for this article.
October 2017: Chinese Clinical Oncology
https://www.readbyqxmd.com/read/29128229/proton-beam-therapy-for-iris-melanomas-in-107-patients
#9
Juliette Thariat, Ahmed Rahmi, Julia Salleron, Carlo Mosci, Benjamin Butet, Celia Maschi, Francesco Lanza, Sara Lanteri, Stephanie Baillif, Joel Herault, Thibaud Mathis, Jean Pierre Caujolle
PURPOSE: To report on the clinical characteristics and outcomes for patients with iris melanoma using proton therapy. DESIGN: Retrospective study. PARTICIPANTS: One hundred seven patients with iris melanoma from 3 regional ophthalmologic centers. METHODS: A retrospective study was conducted for iris melanoma patients from 3 regional ophthalmologic centers referred to and treated at a single proton therapy facility between 1996 and 2015...
November 8, 2017: Ophthalmology
https://www.readbyqxmd.com/read/29120717/cataract-surgery-after-proton-beam-irradiation-for-uveal-tumors
#10
Zeba A Syed, Roberto Pineda
PURPOSE: To study the risks associated with cataract surgery in patients with previous proton-beam irradiation (PBI), focusing on preoperative risk factors, intraoperative findings, and postoperative complications. SETTING: Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA. DESIGN: Retrospective case series. METHODS: Electronic medical records of patients who had PBI and cataract surgery between January 1, 2006, and October 1, 2016, were reviewed...
October 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/29119788/radiochemical-determination-of-long-lived-radionuclides-in-proton-irradiated-heavy-metal-targets-part-i-tantalum
#11
Zeynep Talip, Rugard Dressler, Jean-Christophe David, Christof Vockenhuber, Elisabeth Müller Gubler, Alexander Voegele, Erik Strub, Peter Vontobel, Dorothea Schumann
In this study, distillation, precipitation, and ion exchange methods were choosen for the separation of the long-lived β-emitters (129)I , (36)Cl and the α-emitters (154)Dy, (148)Gd, (150)Gd and (146)Sm from Ta targets irradiated with protons up to 2.6 GeV to determine their production cross sections. Measurements of (129)I/(127)I and (36)Cl/Cl ratios were performed with accelerator mass spectrometry (AMS). After separation of the lanthanides, the molecular plating technique was applied to prepare thin samples to obtain high-resolved α-spectra...
November 9, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29118323/valproic-acid-sensitizes-hepatocellular-carcinoma-cells-to-proton-therapy-by-suppressing-nrf2-activation
#12
Jeong Il Yu, Changhoon Choi, Sung-Won Shin, Arang Son, Ga-Haeng Lee, Shin-Yeong Kim, Hee Chul Park
Although efficacy of combined histone deacetylase (HDAC) inhibitors and conventional photon radiotherapy is being tested in clinical trials, their combined effect with proton beam radiotherapy has yet to be determined. Here, we compared combined effect of valproic acid (VPA), a class I and II HDAC inhibitor and antiepileptic drug with proton and photon irradiation in hepatocellular carcinoma (HCC) cells in vitro and in vivo. We found that VPA sensitized more Hep3B cells to proton than to photon irradiation...
November 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29116399/intravitreal-bevacizumab-for-neovascular-glaucoma-in-uveal-melanoma-treated-by-proton-beam-therapy
#13
Amir Mahdjoubi, Marie Najean, Stéphanie Lemaitre, Sylvain Dureau, Rémi Dendale, Christine Levy, Livia Lumbroso-Le Rouic, Laurence Desjardins, Nathalie Cassoux
BACKGROUND: To evaluate the efficacy of bevacizumab on reduction of the enucleation rate and control of intraocular pressure (IOP) in neovascular glaucoma (NVG)-complicating proton beam therapy for UM and to identify the determinants of the efficacy of bevacizumab. METHODS: Retrospective comparative study of patients with rubeosis following proton therapy for uveal melanoma. Patients were divided into two groups: a bevacizumab group and a control group which comprised two subgroups: panretinal photocoagulation (PRP)/cryotherapy and observation subgroups...
November 7, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/29115339/electro-oxidation-of-a-cobalt-based-steel-in-lioh-a-non-noble-metal-based-electro-catalyst-suitable-for-durable-water-splitting-in-an-acidic-milieu
#14
Helmut Schäfer, Karsten Küpper, Klaus Müller-Buschbaum, Diemo Daum, Martin Steinhart, Joachim Wollschläger, Ulrich Krupp, Mercedes Schmidt, Weijia Han, Johannes Stangl
The use of proton exchange membrane (PEM) electrolyzers is the method of choice for the conversion of solar energy when frequently occurring changes of the current load are an issue. However, this technique requires electrolytes with low pH. All oxygen evolving electrodes working durably and actively in acids contain IrOx. Due to their scarcity and high acquisition costs, noble elements like Pt, Ru and Ir need to be replaced by earth abundant elements. We have evaluated a cobalt containing steel for use as an oxygen-forming electrode in H2SO4...
November 8, 2017: Nanoscale
https://www.readbyqxmd.com/read/29115059/universal-field-matching-in-craniospinal-irradiation-by-a-background-dose-gradient-optimized-method
#15
Erik Traneus, Nicola Bizzocchi, Francesco Fellin, Barbara Rombi, Paolo Farace
PURPOSE: The gradient-optimized methods are overcoming the traditional feathering methods to plan field junctions in craniospinal irradiation. In this note, a new gradient-optimized technique, based on the use of a background dose, is described. METHODS: Treatment planning was performed by RayStation (RaySearch Laboratories, Stockholm, Sweden) on the CT scans of a pediatric patient. Both proton (by pencil beam scanning) and photon (by volumetric modulated arc therapy) treatments were planned with three isocenters...
November 7, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29114596/clinical-outcomes-of-intensity-modulated-proton-therapy-and-concurrent-chemotherapy-in-esophageal-carcinoma-a-single-institutional-experience
#16
Anussara Prayongrat, Cai Xu, Heng Li, Steven H Lin
Purpose: Intensity-modulated proton therapy (IMPT) is an emerging advanced radiation technique. Although dosimetric studies demonstrate the superiority of IMPT for improving target conformity and reducing unnecessary dose to critical normal tissues, clinical experience is limited. We aim to describe our preliminary experience implementing IMPT concurrently with chemotherapy in esophageal carcinoma (EC). Methods and materials: From May 2011 through February 2016, 19 patients with EC (median age, 73 years) were treated with IMPT using 180 to 250 MV protons with a median dose of 50...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29113853/hyperkinetic-transient-ischemic-attacks-preceding-deep-ganglionic-infarction-in-a-patient-with-a-treated-parasellar-chondrosarcoma
#17
Michael W Ruff, Adip G Bhargav, Stephen W English, James P Klaas
A 44-year-old right-handed female with a past medical history of parasellar chondrosarcoma status post-surgical debulking and proton beam therapy (70 Gy) three years prior to presentation experienced several hours of brief, repetitive episodes of transient hemiballism and dystonia; this was followed by abrupt onset of fixed hemiparesis and dysarthria weeks later, ipsilateral to her prior hyperkinetic movements. She was found to have total occlusion of the right middle cerebral artery with focal stenosis of the proximal right A-1 segment of the anterior cerebral artery adjacent to the remnants of the chondrosarcoma...
November 4, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/29113697/sensitivity-of-a-prompt-gamma-slit-camera-to-detect-range-shifts-for-proton-treatment-verification
#18
Lena Nenoff, Marlen Priegnitz, Guillaume Janssens, Johannes Petzoldt, Patrick Wohlfahrt, Anna Trezza, Julien Smeets, Guntram Pausch, Christian Richter
BACKGROUND AND PURPOSE: A prompt-gamma imaging (PGI) slit-camera was recently applied successfully in clinical proton treatments using pencil beam scanning (PBS) and double scattering (DS). However, its full capability under clinical conditions has still to be systematically evaluated. Here, the performance of the slit-camera is systematically assessed in well-defined error scenarios using realistic treatment deliveries to an anthropomorphic head phantom. MATERIALS AND METHODS: The sensitivity and accuracy to detect introduced global and local range shifts with the slit-camera was investigated in PBS and DS irradiations...
November 4, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29106564/modelling-recurrence-and-second-cancer-risks-induced-by-proton-therapy
#19
V S K Manem, A Dhawan
In the past few years, proton therapy has taken the centre stage in treating various tumour types. The primary contribution of this study is to investigate the tumour control probability (TCP), relapse time and the corresponding secondary cancer risks induced by proton beam radiation therapy. We incorporate tumour relapse kinetics into the TCP framework and calculate the associated second cancer risks. To calculate proton therapy-induced secondary cancer induction, we used the well-known biologically motivated mathematical model, initiation-inactivation-proliferation formalism...
July 4, 2017: Mathematical Medicine and Biology: a Journal of the IMA
https://www.readbyqxmd.com/read/29103987/special-radiobiological-features-of-second-cancer-risk-after-particle-radiotherapy
#20
Klaus-Rüdiger Trott
In absolute terms: second cancer risks from radiotherapy of first cancers in adults are small compared to the benefits from radiotherapy but this is not so for radiotherapy of childhood cancers. Moreover, the radiation dose dependence of cancer induction differs between organs and tissues. The organ-specific dose dependence of second cancer risks may indicate the existence of different radiobiological mechanisms. As an inevitable consequence of the age dependence of organ sensitivity to second cancer induction, the organ/tissue weighting factors which have been proposed by ICRP for calculating effective dose (the dose unit Sv) and for risk estimation in the general population should not be used in medical radiation exposures...
November 2, 2017: Physica Medica: PM
keyword
keyword
38412
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"