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Proton Beam

Wook-Geun Shin, Mauro Testa, Hak Soo Kim, Jong Hwi Jeong, Se Byeong Lee, Yeon-Joo Kim, Chul Hee Min
For the independent validation of treatment plans, we developed a Monte Carlo (MC)-based patient dose calculation system with the tool for particle simulation (TOPAS) to enable routine and automatic dose recalculation for each patient. The proton beam nozzle was modeled with TOPAS to simulate the therapeutic beam, and MC commissioning was performed by comparing percent depth dose with the measurement. The beam set-up based on the prescribed beam range and modulation width was automated by modifying the vendor-specific method...
August 15, 2017: Physics in Medicine and Biology
Silva Bortolussi, Ian Postuma, Nicoletta Protti, Lucas Provenzano, Cinzia Ferrari, Laura Cansolino, Paolo Dionigi, Olimpio Galasso, Giorgio Gasparini, Saverio Altieri, Shin-Ichi Miyatake, Sara J González
BACKGROUND: Osteosarcoma is the most frequent primary malignant bone tumour, and its incidence is higher in children and adolescents, for whom it represents more than 10% of solid cancers. Despite the introduction of adjuvant and neo-adjuvant chemotherapy that markedly increased the success rate in the treatment, aggressive surgery is still needed and a considerable percentage of patients do not survive due to recurrences or early metastases. Boron Neutron Capture Therapy (BNCT), an experimental radiotherapy, was investigated as a treatment that could allow a less aggressive surgery by killing infiltrated tumour cells in the surrounding healthy tissues...
August 15, 2017: Radiation Oncology
Christopher P McNary, P B Armentrout
Threshold collision-induced dissociation using a guided ion beam tandem mass spectrometer is performed on (N2H4)H(+)(H2O)n, where n = 1 and 2, and on the protonated unsymmetrical 1,1-dimethylhydrazine one-water complex. The primary dissociation pathway for all clusters is a loss of a single water molecule, which for n = 2 is followed by the sequential loss of an additional water molecule at higher collision energies. The data are analyzed using a statistical model after accounting for internal and kinetic energy distributions, multiple collisions, and kinetic shifts to obtain 0 K bond dissociation energies (BDEs)...
December 7, 2016: Journal of Chemical Physics
Marc-Elie Nader, Diana Bell, Lawrence Ginsberg, Franco DeMonte, G Brandon Gunn, Paul W Gidley
OBJECTIVE: Adenocarcinoma of the middle ear is a rare entity that must be distinguished from other adenomatous tumors of the temporal bone. We present the first patient of an intestinal-type adenocarcinoma originating from the middle ear. PATIENTS: A 58-year-old woman presented with an 8-year history of left otorrhea. Her middle ear effusions were quite thick and gummy. She underwent eight sets of pressure-equalization tubes within 3 years. In 2011, her physical examination identified a middle ear mass, and she underwent mastoidectomy...
August 8, 2017: Otology & Neurotology
Eric Ojerholm, Christine E Hill-Kayser
Proton beam therapy (PBT) holds promise for pediatric patients, but level 1 evidence is not available. In this context, we examined insurance coverage decisions at our facility from 2010 to 2015. PBT was initially denied for 11% of pediatric cases. However, nearly all denials were overturned on appeal-a process that often delayed care by more than a week. Despite unfavorable language in coverage policies, real-world decisions were eventual approval in >99% of cases. Payers appear to have largely accepted the current level-of-evidence for pediatric PBT, but all parties spend significant time and resources on appeals...
August 7, 2017: Pediatric Blood & Cancer
Jiajian Shen, Erik Tryggestad, James E Younkin, Sameer R Keole, Keith M Furutani, Yixiu Kang, Michael G Herman, Martin Bues
PURPOSE: To accurately model the beam delivery time (BDT) for a synchrotron based proton spot scanning system using experimentally determined beam parameters. METHODS: A model to simulate the proton spot delivery sequences was constructed and BDT was calculated by summing times for layer switch, spot switch and spot delivery. Test plans were designed to isolate and quantify the relevant beam parameters in the operation cycle of the proton beam therapy delivery system...
August 4, 2017: Medical Physics
Xuanfeng Ding, Xiaoqiang Li, An Qin, Jun Zhou, Di Yan, Craig Stevens, Daniel Krauss, Peyman Kabolizdeh
No abstract text is available yet for this article.
August 3, 2017: Acta Oncologica
Jonathan G Gigax, Philip D Bradford, Lin Shao
We studied the effects ion beam irradiation on carbon nanotube (CNT) yarns. CNT yarn was fabricated by drawing and spinning CNT sheets from a vertically aligned CNT forest. The yarn was irradiated by 2.5 MeV protons in either vacuum or air. Irradiation in air was achieved by directing the proton beam through a 0.025 mm thick Ti window. Irradiation in vacuum occurred at a pressure of <10(-6) torr at room temperature and at an elevated temperature of 600 °C. Tensile testing revealed that CNT yarn irradiated in air increased in tensile strength with increasing proton fluence...
July 27, 2017: Materials
Sylvain Deffet, Benoît Macq, Roberto Righetto, François Vander Stappen, Paolo Farace
PURPOSE: Proton radiography seems to be a promising tool for assessing the quality of the stopping power computation in proton therapy. However, range error maps obtained on the basis of proton radiographs are very sensitive to small misalignment between the planning CT and the proton radiography acquisitions. In order to be able to mitigate misalignment in post-processing, the authors implemented a fast method for registration between pencil proton radiography data obtained with a multilayer ionization chamber (MLIC) and an X-ray CT acquired on a head phantom...
August 3, 2017: Medical Physics
Damien C Weber, André Abrunhosa-Branquinho, Alessandra Bolsi, Andrzej Kacperek, Rémi Dendale, Dirk Geismar, Barbara Bachtiary, Annika Hall, Jens Heufelder, Klaus Herfarth, Jürgen Debus, Maurizio Amichetti, Mechthild Krause, Roberto Orecchia, Vladimir Vondracek, Juliette Thariat, Tomasz Kajdrowicz, Kristina Nilsson, Cai Grau
BACKGROUND: We performed a survey using the modified EORTC Facility questionnaire (pFQ) to evaluate the human, technical and organizational resources of particle centers in Europe. MATERIAL AND METHODS: The modified pFQ consisted of 235 questions distributed in 11 sections accessible on line on an EORTC server. Fifteen centers from 8 countries completed the pFQ between May 2015 and December 2015. RESULTS: The average number of patients treated per year and per particle center was 221 (range, 40-557)...
July 29, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
N P Dover, M Nishiuchi, H Sakaki, M A Alkhimova, A Ya Faenov, Y Fukuda, H Kiriyama, A Kon, K Kondo, K Nishitani, K Ogura, T A Pikuz, A S Pirozhkov, A Sagisaka, M Kando, K Kondo
A high repetition rate scintillator-based transverse beam profile diagnostic for laser-plasma accelerated proton beams has been designed and commissioned. The proton beam profiler uses differential filtering to provide coarse energy resolution and a flexible design to allow optimisation for expected beam energy range and trade-off between spatial and energy resolution depending on the application. A plastic scintillator detector, imaged with a standard 12-bit scientific camera, allows data to be taken at a high repetition rate...
July 2017: Review of Scientific Instruments
Ulrike Diebold
The interaction of water with the single-crystalline rutile TiO2(110) surface has been the object of intense investigations with both experimental and computational methods. Not only is TiO2(110) widely considered the prototypical oxide surface, its interaction with water is also important in many applications where this material is used. At first, experimental measurements were hampered by the fact that preparation recipes for well-controlled surfaces had yet to be developed, but clear experimental evidence that water dissociation at defects including oxygen vacancies and steps emerged...
July 28, 2017: Journal of Chemical Physics
Alexandre Matet, Alejandra Daruich, Leonidas Zografos
Purpose: To analyze microvascular and structural changes in radiation maculopathy and their influence on visual acuity (VA), using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: This was a retrospective analysis of consecutive patients with radiation maculopathy, 12 months or more after proton-beam irradiation for uveal melanoma, imaged with fluorescein angiography, OCT, and OCTA. Clinical parameters potentially affecting VA were recorded, including OCTA-derived metrics: foveal avascular zone (FAZ) area, vascular density, and local fractal dimension of the superficial (SCP) and deep capillary plexuses (DCP)...
August 1, 2017: Investigative Ophthalmology & Visual Science
T Tessonnier, A Mairani, S Brons, P Sala, F Cerutti, A Ferrari, T Haberer, J Debus, K Parodi
In the field of particle therapy helium ion beams could offer an alternative for radiotherapy treatments, owing to their interesting physical and biological properties intermediate between protons and carbon ions. We present in this work the comparisons and validations of the Monte Carlo FLUKA code against in-depth dosimetric measurements acquired at the Heidelberg Ion Beam Therapy Center (HIT). Depth dose distributions in water with and without ripple filter, lateral profiles at different depths in water and a spread-out Bragg peak were investigated...
August 1, 2017: Physics in Medicine and Biology
Annika Jakobi, Rosalind Perrin, Antje Knopf, Christian Richter
BACKGROUND: The interplay effect might degrade the dose of pencil beam scanning proton therapy to a degree that free-breathing treatment might be impossible without further motion mitigation techniques, which complicate and prolong the treatment. We assessed whether treatment of free-breathing patients without motion mitigation is feasible. MATERIAL AND METHODS: For 40 lung cancer patients, 4DCT datasets and individual breathing patterns were used to simulate 4D dynamic dose distributions of 3D treatment plans over 33 fractions delivered with an IBA universal nozzle...
August 1, 2017: Acta Oncologica
Fabio Y Moraes, Caroline Chung
Skull base meningiomas (SBM) pose unique challenges for radiotherapy as these tumors are often in close proximity to a number of critical structures and may not be surgically addressed in many cases, leaving the question about the tumor grade and expected biological behaviour. External beam radiotherapy and radiosurgery are longstanding treatments for meningioma that are typically used as upfront primary therapy, for recurrent tumors and as adjuvant therapy following surgical resection. There is controversy regarding the optimal timing and approach for radiation therapy in various clinical settings such as the role of adjuvant radiotherapy for completely resected grade 2 tumours...
July 2017: Chinese Clinical Oncology
Manjulika Das
No abstract text is available yet for this article.
July 27, 2017: Lancet Oncology
Mansour Almurayshid, Yusuf Helo, Andrzej Kacperek, Jennifer Griffiths, Jem Hebden, Adam Gibson
PURPOSE: In this article, we evaluate a plastic scintillation detector system for quality assurance in proton therapy using a BC-408 plastic scintillator, a commercial camera, and a computer. METHODS: The basic characteristics of the system were assessed in a series of proton irradiations. The reproducibility and response to changes of dose, dose-rate, and proton energy were determined. Photographs of the scintillation light distributions were acquired, and compared with Geant4 Monte Carlo simulations and with depth-dose curves measured with an ionization chamber...
July 29, 2017: Journal of Applied Clinical Medical Physics
S Štajner, P Achenbach, T Beranek, J Beričič, J C Bernauer, D Bosnar, R Böhm, L Correa, A Denig, M O Distler, A Esser, H Fonvieille, J M Friedrich, I Friščić, S Kegel, Y Kohl, H Merkel, M Mihovilovič, J Müller, U Müller, L Nungesser, J Pochodzalla, B S Schlimme, M Schoth, F Schulz, C Sfienti, S Širca, M Thiel, L Tiator, A Tyukin, A Weber, I Yaron
The helicity-dependent recoil proton polarizations P_{x}^{'} and P_{z}^{'} as well as the helicity-independent component P_{y} have been measured in the p(e[over →],e^{'}p[over →])π^{0} reaction at four-momentum transfer Q^{2}≃0.1  GeV^{2}, center-of-mass proton emission angle θ_{p}^{*}≃90°, and invariant mass W≃1440  MeV. This first precise measurement of double-polarization observables in the energy domain of the Roper resonance P_{11}(1440) by exploiting recoil polarimetry has allowed for the extraction of its scalar electroexcitation amplitude at an unprecedentedly low value of Q^{2}, establishing a powerful instrument for probing the interplay of quark and meson degrees of freedom in the nucleon...
July 14, 2017: Physical Review Letters
Seung-Jun Seo, Jae-Kun Jeon, Sung-Mi Han, Jong-Ki Kim
PURPOSE: The Coulomb nanoradiator (CNR) effect produces the dose enhancement effects from high-Z nanoparticles under irradiation with a high-energy ion beam. To gain insight into the radiation dose and biological significance of the CNR effect, the enhancement of reactive oxygen species (ROS) production from iron oxide or gold NPs (IONs or AuNPs, respectively) in water was investigated using traversing proton beams. METHODS AND MATERIALS: The dependence of nanoradiator-enhanced ROS production on the atomic Z value and proton energy was investigated...
August 16, 2017: International Journal of Radiation Biology
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