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https://www.readbyqxmd.com/read/28333688/treatment-planning-of-intensity-modulated-composite-particle-therapy-with-dose-and-linear-energy-transfer-optimization
#1
Taku Inaniwa, Nobuyuki Kanematsu, Koji Noda, Tadashi Kamada
The biological effect of charged-particle beams depends on both dose and radiation quality. The radiation quality of charged-particle beams has been most commonly represented by the linear energy transfer (LET) in radiation biology studies. We investigated a new therapeutic technique using two or more ion species in one treatment session, which we call an Intensity Modulated composite PArtiCle Therapy (IMPACT), for optimizing the physical dose and dose-averaged LET distributions in a patient as its proof of principle...
March 23, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28332994/predicting-patient-specific-dosimetric-benefits-of-proton-therapy-for-skull-base-tumors-using-a-geometric-knowledge-based-method
#2
David C Hall, Alexei V Trofimov, Brian A Winey, Norbert J Liebsch, Harald Paganetti
PURPOSE: To predict the organ at risk (OAR) dose levels achievable with proton beam therapy (PBT), solely based on the geometric arrangement of the target volume in relation to the OARs. A comparison with an alternative therapy yields a prediction of the patient-specific benefits offered by PBT. This could enable physicians at hospitals without proton capabilities to make a better-informed referral decision or aid patient selection in model-based clinical trials. METHODS AND MATERIALS: Skull-base tumors were chosen to test the method, owing to their geometric complexity and multitude of nearby OARs...
April 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28321635/relative-biological-effectiveness-in-a-proton-spread-out-bragg-peak-formed-by-pencil-beam-scanning-mode
#3
Anna Michaelidesová, Jana Vachelová, Monika Puchalska, Kateřina Pachnerová Brabcová, Vladimír Vondráček, Lembit Sihver, Marie Davídková
In recent years, there is an increased interest in using scanning modes in proton therapy, due to the more conformal dose distributions, thanks to the spot-weighted dose delivery. The dose rate in each spot is however much higher than the dose rate when using passive irradiation modes, which could affect the cell response. The purpose of this work was to investigate how the relative biological effectiveness changes along the spread-out Bragg peak created by protons delivered by the pencil beam scanning mode...
March 20, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28319031/evaluation-of-the-water-equivalence-of-plastic-materials-in-low-and-high-energy-clinical-proton-beams
#4
Ana Lourenco, David Shipley, Nigel Wellock, Russell Thomas, Hugo Bouchard, Andrzej Kacperek, Francesco Fracchiolla, Stefano Lorentini, Marco Schwarz, Niall MacDougall, Gary Royle, Hugo Palmans
The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, <i>H</i><sub><i>pl</i>,w</sub>. Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code...
March 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28306315/hard-two-photon-contribution-to-elastic-lepton-proton-scattering-determined-by-the-olympus-experiment
#5
B S Henderson, L D Ice, D Khaneft, C O'Connor, R Russell, A Schmidt, J C Bernauer, M Kohl, N Akopov, R Alarcon, O Ates, A Avetisyan, R Beck, S Belostotski, J Bessuille, F Brinker, J R Calarco, V Carassiti, E Cisbani, G Ciullo, M Contalbrigo, R De Leo, J Diefenbach, T W Donnelly, K Dow, G Elbakian, P D Eversheim, S Frullani, Ch Funke, G Gavrilov, B Gläser, N Görrissen, D K Hasell, J Hauschildt, Ph Hoffmeister, Y Holler, E Ihloff, A Izotov, R Kaiser, G Karyan, J Kelsey, A Kiselev, P Klassen, A Krivshich, I Lehmann, P Lenisa, D Lenz, S Lumsden, Y Ma, F Maas, H Marukyan, O Miklukho, R G Milner, A Movsisyan, M Murray, Y Naryshkin, R Perez Benito, R Perrino, R P Redwine, D Rodríguez Piñeiro, G Rosner, U Schneekloth, B Seitz, M Statera, A Thiel, H Vardanyan, D Veretennikov, C Vidal, A Winnebeck, V Yeganov
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20° to 80°...
March 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28304223/metastatic-clival-chordoma-a-case-report-of-multiple-extraneural-metastases-following-resection-and-proton-beam-radiotherapy-in-a-5-year-old-boy
#6
Martin J Rutkowski, Harjus S Birk, Matthew D Wood, Arie Perry, Theodore Nicolaides, Christopher P Ames, Nalin Gupta
The authors report the case of a 5-year-old boy in whom extraneural metastases developed 5 years after he underwent an occipitocervical fusion and transoral approach to treat a clival chordoma without local recurrence. Following primary resection, the patient's postoperative course was complicated by recurrent meningitis secondary to CSF leak, which responded to antibiotics, and communicating hydrocephalus, for which a ventriculoperitoneal shunt was placed. The patient then underwent postoperative proton beam radiotherapy...
March 17, 2017: Journal of Neurosurgery. Pediatrics
https://www.readbyqxmd.com/read/28300385/a-benchmarking-method-to-evaluate-the-accuracy-of-a-commercial-proton-monte-carlo-pencil-beam-scanning-treatment-planning-system
#7
Liyong Lin, Sheng Huang, Minglei Kang, Petri Hiltunen, Reynald Vanderstraeten, Jari Lindberg, Sami Siljamaki, Todd Wareing, Ian Davis, Allen Barnett, John McGhee, Charles B Simone, Timothy D Solberg, James E McDonough, Christopher Ainsley
AcurosPT is a Monte Carlo algorithm in the Eclipse 13.7 treatment planning system, which is designed to provide rapid and accurate dose calculations for proton therapy. Computational run-time in minimized by simplifying or eliminating less significant physics processes. In this article, the accuracy of AcurosPT was benchmarked against both measurement and an independent MC calculation, TOPAS. Such a method can be applied to any new MC calculation for the detection of potential inaccuracies. To validate multiple Coulomb scattering (MCS) which affects primary beam broadening, single spot profiles in a Solidwater(®) phantom were compared for beams of five selected proton energies between AcurosPT, measurement and TOPAS...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297992/monte-carlo-approach-to-calculate-proton-stopping-in-warm-dense-matter-within-particle-in-cell-simulations
#8
D Wu, X T He, W Yu, S Fritzsche
A Monte Carlo approach to proton stopping in warm dense matter is implemented into an existing particle-in-cell code. This approach is based on multiple electron-electron, electron-ion, and ion-ion binary collision and accounts for both the free and the bound electrons in the plasmas. This approach enables one to calculate the stopping of particles in a more natural manner than existing theoretical treatment. In the low-temperature limit, when "all" electrons are bound to the nucleus, the stopping power coincides with the predictions from the Bethe-Bloch formula and is consistent with the data from the National Institute of Standard and Technology database...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28297858/quantitative-shadowgraphy-and-proton-radiography-for-large-intensity-modulations
#9
Muhammad Firmansyah Kasim, Luke Ceurvorst, Naren Ratan, James Sadler, Nicholas Chen, Alexander Sävert, Raoul Trines, Robert Bingham, Philip N Burrows, Malte C Kaluza, Peter Norreys
Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the nonlinear nature of the process. Here, we present a method to retrieve quantitative information from shadowgrams, based on computational geometry...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28297453/spot-scanning-proton-therapy-minimizes-neutron-dose-in-the-setting-of-radiation-therapy-administered-during-pregnancy
#10
Xin Wang, Falk Poenisch, Narayan Sahoo, Ronald X Zhu, MingFwu Lii, Michael T Gillin, Jing Li, David Grosshans
This is a real case study to minimize the neutron dose equivalent (H) to a fetus using spot scanning proton beams with favorable beam energies and angles. Minimum neutron dose exposure to the fetus was achieved with iterative planning under the guidance of neutron H measurement. Two highly conformal treatment plans, each with three spot scanning beams, were planned to treat a 25-year-old pregnant female with aggressive recurrent chordoma of the base of skull who elected not to proceed with termination. Each plan was scheduled for delivery every other day for robust target coverage...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297425/investigation-on-using-high-energy-proton-beam-for-total-body-irradiation-tbi
#11
Miao Zhang, Nan Qin, Xun Jia, Wei J Zou, Atif Khan, Ning J Yue
This work investigated the possibility of using proton beam for total body irradiation (TBI). We hypothesized the broad-slow-rising entrance dose from a monoenergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon-based TBI, it would not require any patient-specific compensator or beam spoiler. The hypothesis was first tested by simulating 250 MeV, 275 MeV, and 300 MeV protons irradiating a wedge-shaped water phantom in a paired opposing arrangement using Monte Carlo (MC) method...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28295434/the-potential-of-dual-energy-ct-to-reduce-proton-beam-range-uncertainties
#12
Esther Bär, Arthur Lalonde, Gary Royle, Hsiao-Ming Lu, Hugo Bouchard
PURPOSE: Dual-energy CT (DECT) promises improvements in estimating stopping power ratios (SPRs) for proton therapy treatment planning. Although several comparable mathematical formalisms have been proposed in literature, the optimal techniques to characterize human tissue SPRs with DECT in a clinical environment are not fully established. The aim of this work is to compare the most robust DECT methods against conventional single-energy CT (SECT) in conditions reproducing a clinical environment, where CT artifacts and noise play a major role on the accuracy of these techniques...
March 15, 2017: Medical Physics
https://www.readbyqxmd.com/read/28294362/systematic-out-of-field-secondary-neutron-spectrometry-and-dosimetry-in-pencil-beam-scanning-proton-therapy
#13
Sebastian Trinkl, Vladimir Mares, Franz Siegfried Englbrecht, Jan Jakob Wilkens, Marek Wielunski, Katia Parodi, Werner Rühm, Martin Hillbrand
BACKGROUND AND PURPOSE: Systematic investigation of the energy and angular dependence of secondary neutron fluence energy distributions and ambient dose equivalents values (H*(10)) inside a pencil beam scanning proton therapy treatment room using a gantry. MATERIAL AND METHODS: Neutron fluence energy distributions were measured with an extended-range Bonner sphere spectrometer featuring ³He proportional counters, at four positions at 0°, 45°, 90° and 135° with respect to beam direction and at a distance of 2 m from the isocenter...
March 11, 2017: Medical Physics
https://www.readbyqxmd.com/read/28291917/rectal-dose-to-prostate-cancer-patients-treated-with-proton-therapy-with-or-without-rectal-spacer
#14
Heeteak Chung, Jerimy Polf, Shahed Badiyan, Matthew Biagioli, Daniel Fernandez, Kujtim Latifi, Richard Wilder, Minesh Mehta, Michael Chuong
The purpose of this study was to evaluate whether a spacer inserted in the prerectal space could reduce modeled rectal dose and toxicity rates for patients with prostate cancer treated in silico with pencil beam scanning (PBS) proton therapy. A total of 20 patients were included in this study who received photon therapy (12 with rectal spacer (DuraSeal™ gel) and 8 without). Two PBS treatment plans were retrospectively created for each patient using the following beam arrangements: (1) lateral-opposed (LAT) fields and (2) left and right anterior oblique (LAO/RAO) fields...
January 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28288673/using-field-size-factors-to-characterize-the-in-air-fluence-of-a-proton-machine-with-a-range-shifter
#15
Jiajian Shen, Jarrod M Lentz, Yanle Hu, Wei Liu, Danairis Hernandez Morales, Joshua B Stoker, Martin Bues
INTRODUCTION: The range shifter (RS) is used to treat shallow tumors for a proton pencil beam scanning system (PBS). Adding RS certainly complicates the commissioning of the treatment planning system (TPS) because the spot sizes are significantly enlarged with RS. In this work, we present an efficient method to configure a commercial TPS for a PBS system with a fixed RS. METHODS: By combining a spiral delivery with customized control points, we were able to significantly improve measurement efficiency and obtain 250 field size factors (FSF) within three hours...
March 14, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28288384/bulk-production-and-evaluation-of-high-specific-activity-186g-re-for-cancer-therapy-using-enriched-186-wo3-targets-in-a-proton-beam
#16
Tara Mastren, Valery Radchenko, Hong T Bach, Ethan R Balkin, Eva R Birnbaum, Mark Brugh, Jonathan W Engle, Matthew D Gott, James Guthrie, Heather M Hennkens, Kevin D John, Alan R Ketring, Marina Kuchuk, Joel R Maassen, Cleo M Naranjo, F Meiring Nortier, Tim E Phelps, Silvia S Jurisson, D Scott Wilbur, Michael E Fassbender
INTRODUCTION: Rhenium-186g (t1/2 = 3.72 d) is a β(-) emitting isotope suitable for theranostic applications. Current production methods rely on reactor production by way of the reaction (185)Re(n,γ)(186g)Re, which results in low specific activities limiting its use for cancer therapy. Production via charged particle activation of enriched (186)W results in a (186g)Re product with a higher specific activity, allowing it to be used more broadly for targeted radiotherapy applications. This targets the unmet clinical need for more efficient radiotherapeutics...
March 3, 2017: Nuclear Medicine and Biology
https://www.readbyqxmd.com/read/28283192/supine-craniospinal-irradiation-in-pediatric-patients-by-proton-pencil-beam-scanning
#17
Paolo Farace, Nicola Bizzocchi, Roberto Righetto, Francesco Fellin, Francesco Fracchiolla, Stefano Lorentini, Lamberto Widesott, Carlo Algranati, Barbara Rombi, Sabina Vennarini, Maurizio Amichetti, Marco Schwarz
BACKGROUND AND PURPOSE: Proton therapy is the emerging treatment modality for craniospinal irradiation (CSI) in pediatric patients. Herein, special methods adopted for CSI at proton Therapy Center of Trento by pencil beam scanning (PBS) are comprehensively described. MATERIALS AND METHODS: Twelve pediatric patients were treated by proton PBS using two/three isocenters. Special methods refer to: (i) patient positioning in supine position on immobilization devices crossed by the beams; (ii) planning field-junctions via the ancillary-beam technique; (iii) achieving lens-sparing by three-beams whole-brain-irradiation; (iv) applying a movable-snout and beam-splitting technique to reduce the lateral penumbra...
March 7, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28281862/model-based-approach-for-quantitative-estimates-of-skin-heart-and-lung-toxicity-risk-for-left-side-photon-and-proton-irradiation-after-breast-conserving-surgery
#18
Francesco Tommasino, Marco Durante, Vittoria D'Avino, Raffaele Liuzzi, Manuel Conson, Paolo Farace, Giuseppe Palma, Marco Schwarz, Laura Cella, Roberto Pacelli
BACKGROUND: Proton beam therapy represents a promising modality for left-side breast cancer (BC) treatment, but concerns have been raised about skin toxicity and poor cosmesis. The aim of this study is to apply skin normal tissue complication probability (NTCP) model for intensity modulated proton therapy (IMPT) optimization in left-side BC. MATERIAL AND METHODS: Ten left-side BC patients undergoing photon irradiation after breast-conserving surgery were randomly selected from our clinical database...
March 10, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28281357/comparison-of-gastric-cancer-radiotherapy-performed-with-volumetric-modulated-arc-therapy-or-single-field-uniform-dose-proton-therapy
#19
Gracinda Mondlane, Michael Gubanski, Pehr A Lind, Ana Ureba, Albert Siegbahn
BACKGROUND: Proton-beam therapy of large abdominal cancers has been questioned due to the large variations in tissue density in the abdomen. The aim of this study was to evaluate the importance of these variations for the dose distributions produced in adjuvant radiotherapy of gastric cancer (GC), implemented with photon-based volumetric modulated arc therapy (VMAT) or with proton-beam single-field uniform-dose (SFUD) method. MATERIAL AND METHODS: Eight GC patients were included in this study...
March 10, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28273345/feasibility-study-of-using-fall-off-gradients-of-early-and-late-pet-scans-for-proton-range-verification
#20
Jongmin Cho, Kira Grogg, Chul Hee Min, Xuping Zhu, Harald Paganetti, Hyun Cheol Lee, Georges El Fakhri
PURPOSE: While positron emission tomography (PET) allows for the imaging of tissues activated by proton beams in terms of monitoring the therapy administered, most endogenous tissue elements are activated by relatively high energy protons. Therefore, a relatively large distance off-set exists between the dose fall-off and activity fall-off. However, (16) O(p,2p,2n)(13) N has a relatively low energy threshold which peaks around 12 MeV and also a residual proton range that is approximately 1 to 2 mm...
March 8, 2017: Medical Physics
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