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Proton beam therapy

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https://www.readbyqxmd.com/read/28635614/advanced-treatment-planning-using-direct-4d-optimisation-for-pencil-beam-scanned-particle-therapy
#1
Kinga Bernatowicz, Ye Zhang, Rosalind Lucy Perrin, Damien Charles Weber, Antony John Lomax
We report on development of a new four-dimensional (4D) optimisation approach for scanned proton beams, which incorporates both irregular motion patterns and the delivery dynamics of the treatment machine into the plan optimiser. Furthermore, we assess the effectiveness of this technique to reduce dose to critical structures in proximity to moving targets, while maintaining effective target dose homogeneity and coverage. The proposed approach has been tested using both a simulated phantom and a clinical liver cancer case, and allows for realistic 4D calculations and optimisation using irregular breathing patterns extracted from e...
June 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28631017/proton-therapy-of-iris-melanoma-with-50%C3%A2-cge-influence-of-target-volume-on-clinical-outcome
#2
Aline I Riechardt, Bettina Karle, Dino Cordini, Jens Heufelder, Volker Budach, Antonia M Joussen, Johannes Gollrad
PURPOSE: The aim of this study was to evaluate local tumour control, incidence of radiation-induced glaucoma and associated interventions of sector-based and whole anterior segment proton beam therapy (PBT) for the treatment of iris melanoma. PATIENTS AND METHODS: We retrospectively analysed the data of 77 patients with iris melanoma who underwent PBT applied as 50 CGE in four daily fractions. Of the patients, 47 received PBT with a circular-shaped collimator and 30 with a conformal sector-shaped target volume...
June 19, 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/28630005/transgenerational-effects-of-proton-beam-irradiation-on-caenorhabditis-elegans-germline-apoptosis
#3
Hyemin Min, Minhee Sung, Miseol Son, Ichiro Kawasaki, Yhong-Hee Shims
When treating cancer using radiation therapy, it is critical to increase patient survival rates and to reduce side effects. In this respect, proton beam radiation treatment performs better than other radiation treatments because of its high target specificity. However, complications still remain after proton beam radiation treatment. Among them, the risk to progeny after irradiation of their parents is a major concern. In this study, we analyzed the transgenerational effects of proton beam irradiation using the model organism Caenorhabditis...
June 16, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28627000/pencil-beam-scanned-protons-for-the-treatment-of-patients-with-ewing-sarcoma
#4
Damien C Weber, Fritz R Murray, Dora Correia, Alessandra Bolsi, Martina Frei-Welte, Alessia Pica, Antony J Lomax, Ralf Schneider, Barbara Bachtiary
BACKGROUND: Few data exist regarding the clinical outcome of patients with Ewing sarcoma (EWS) treated with pencil beam scanning proton therapy (PT). We report the outcome of children, adolescents and young adults (AYA) treated with PT at the Paul Scherrer Institute. MATERIALS: Thirty-eight patients (median age, 9.9 years) received a median dose of 54.9 Gy(RBE) (where RBE is relative biologic effectiveness). Size of the tumor ranged from 1.7 to 24 cm. Most common primary site was axial/pelvic (n = 27; 71%)...
June 19, 2017: Pediatric Blood & Cancer
https://www.readbyqxmd.com/read/28623412/long-term-follow-up-after-endoscopic-trans-sphenoidal-surgery-or-initial-observation-in-clivus-chordomas
#5
Jon Ramm-Pettersen, Radek Frič, Jon Berg-Johnsen
BACKGROUND: Resection of clivus chordomas through extensive skull base approaches is associated with high mortality and morbidity even in experienced hands. We report our experience with endoscopic trans-sphenoidal surgery, or a "wait-and-scan" strategy in selected patients. METHOD: Ten patients were diagnosed with clivus chordomas during an 8-year period. Six patients underwent primary treatment with endoscopic trans-sphenoidal surgery, followed by adjuvant proton-beam therapy in three of these patients...
June 16, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/28610689/experimental-assessment-of-proton-dose-calculation-accuracy-in-inhomogeneous-media
#6
J Sorriaux, M Testa, H Paganetti, J Orban de Xivry, J A Lee, E Traneus, K Souris, S Vynckier, E Sterpin
PURPOSE: Proton therapy with Pencil Beam Scanning (PBS) has the potential to improve radiotherapy treatments. Unfortunately, its promises are jeopardized by the sensitivity of the dose distributions to uncertainties, including dose calculation accuracy in inhomogeneous media. Monte Carlo dose engines (MC) are expected to handle heterogeneities better than analytical algorithms like the pencil-beam convolution algorithm (PBA). In this study, an experimental phantom has been devised to maximize the effect of heterogeneities and to quantify the capability of several dose engines (MC and PBA) to handle these...
June 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28609301/a-light-weight-compact-proton-gantry-design-with-a-novel-dose-delivery-system-for-broad-energetic-laser-accelerated-beams
#7
U Masood, T E Cowan, W Enghardt, K M Hofmann, L Karsch, F Kroll, U Schramm, J J Wilkens, J Pawelke
Proton beams may provide superior dose-conformity in radiation therapy. However, the large sizes and costs limit the widespread use of proton therapy (PT). The recent progress in proton acceleration via high-power laser systems has made it a compelling alternative to conventional accelerators, as it could potentially reduce the overall size and cost of the PT facilities. However, the laser-accelerated beams exhibit different characteristics than conventionally accelerated beams, i.e. very intense proton bunches with large divergences and broad-energy spectra...
July 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28605745/current-standard-and-future-perspectives-in-non-surgical-therapy-for-hepatocellular-carcinoma
#8
Tobias Eggert, Tim F Greten
BACKGROUND: Hepatocellular carcinoma (HCC) is an aggressive liver tumor with a poor 5-year survival rate. Many HCCs are not amenable to surgical resection, because of tumor size, location, or because of the patient's poor liver function, a common obstacle to HCC therapy, because HCCs almost always develop in chronically inflamed livers. SUMMARY: In recent years, many efforts have been made to improve patient survival by conducting clinical trials investigating local and systemic treatment options for patients with unresectable tumors...
June 13, 2017: Digestion
https://www.readbyqxmd.com/read/28596284/prognostic-biopsy-of-choroidal-melanoma-an-optimised-surgical-and-laboratory-approach
#9
Martina Angi, Helen Kalirai, Azzam Taktak, Rumana Hussain, Carl Groenewald, Bertil E Damato, Heinrich Heimann, Sarah E Coupland
BACKGROUND: Accurate survival prognostication for patients with uveal melanoma (UM) enables effective patient counselling and permits personalised systemic surveillance for the early detection of metastases and, in high-risk patients, enrolment in any trials of systemic adjuvant therapy. The aim of this work is to determine the success of prognostic UM tumour biopsy using an improved surgical approach and optimised sample handling workflow. METHODS: Patients with UM treated by primary radiotherapy between 2011 and 2013 and who underwent a prognostic biopsy with cytology, multiplex ligation-dependent probe amplification and/or microsatellite analysis were included...
June 8, 2017: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28593931/performance-characterization-of-a-3d-liquid-scintillation-detector-for-discrete-spot-scanning-proton-beam-systems
#10
Chinmay Darne, Fahed Alsanea, Daniel Robertson, Narayan Sahoo, Sam Beddar
Existing systems for proton beam dosimetry are limited in their ability to provide a complete, accurate, and detailed account of volumetric dose distribution. In this work, we describe the design and development of a portable, fast, and reusable liquid scintillator-based three-dimensional (3D) optical detection system for use in proton therapy. Our long-term goal is to use this system clinically for beam characterization, dosimetry, and quality assurance studies of discrete spot scanning proton beam systems...
June 8, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28582266/a-beam-monitoring-and-validation-system-for-continuous-line-scanning-in-proton-therapy
#11
Grischa Klimpki, Serena Psoroulas, Christian Bula, Urs Rechsteiner, Michael Eichin, Damien Weber, Antony Lomax, David Meer
Line scanning represents a faster and potentially more flexible form of pencil beam scanning than conventional <i>step-and-shoot</i> irradiations. It seeks to minimize dead times in beam delivery whilst preserving the possibility to modulate the dose at any point in the target volume. Our second generation proton gantry features irradiations in line scanning mode, but it still lacks a dedicated monitoring and validation system that guarantees patient safety throughout beam delivery. We report on its design and implementation in this paper...
June 5, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28582265/application-of-fluence-field-modulation-to-proton-computed-tomography-for-proton-therapy-imaging
#12
Georgios Dedes, Ludovica De Angelis, Simon Rit, David Hansen, Claus Belka, Vladimir Bashkirov, Robert Johnson, George Coutrakon, Keith Schubert, Guillaume Landry, Reinhard Schulte, Katia Parodi
This simulation study presents the application of fluence field modulated computed tomography (FFMCT), initially developed for x-ray CT, to proton computed tomography (pCT). By using pencil beam (PB) scanning, fluence modulated pCT (FMpCT) may achieve variable image quality in a pCT image and imaging dose reduction. Three virtual phantoms, a uniform cylinder and two patients, were studied using Monte Carlo simulations of an ideal list-mode pCT scanner. Regions of interests (ROI) were selected for high image quality and only PBs intercepting them preserved full fluence (FF)...
June 5, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28580706/mr-techniques-for-guiding-high-intensity-focused-ultrasound-hifu-treatments
#13
REVIEW
Kagayaki Kuroda
To make full use of the ability of magnetic resonance (MR) to guide high-intensity focused ultrasound (HIFU) treatment, effort has been made to improve techniques for thermometry, motion tracking, and sound beam visualization. For monitoring rapid temperature elevation with proton resonance frequency (PRF) shift, data acquisition and processing can be accelerated with parallel imaging and/or sparse sampling in conjunction with appropriate signal processing methods. Thermometry should be robust against tissue motion, motion-induced magnetic field variation, and susceptibility change...
June 5, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28569997/impact-of-spot-charge-inaccuracies-in-impt-treatments
#14
Aafke C Kraan, Nicolas Depauw, Ben Clasie, Marina Giunta, Tom Madden, Hanne M Kooy
BACKGROUND: Spot charge is one parameter of pencil-beam scanning dose delivery system whose accuracy is typically high but whose required value has not been investigated. In this work we quantify the dose impact of spot charge inaccuracies on the dose distribution in patients. Knowing the effect of charge errors is relevant for conventional proton machines, as well as for new generation proton machines, where ensuring accurate charge may be challenging. METHODS: Through perturbation of spot charge in treatment plans for 7 patients and a phantom, we evaluated the dose impact of absolute (up to 5 X 10(6) protons) and relative (up to 30%) charge errors...
June 1, 2017: Medical Physics
https://www.readbyqxmd.com/read/28556241/carbon-and-oxygen-minibeam-radiation-therapy-an-experimental-dosimetric-evaluation
#15
Immaculada Martínez-Rovira, Wilfredo González, Stephan Brons, Yolanda Prezado
PURPOSE: To perform dosimetric characterization of a minibeam collimator in both carbon and oxygen ion beams to guide optimal set up geometry and irradiation for future radiobiological studies using these beams. METHODS: Carbon and oxygen minibeams were generated using a prototype tungsten multislit collimator presenting line apertures 700 μm wide, which are spaced 3500 μm centre-to-centre distance apart. Several radiation beam spots generated the desired field size of 15X15 mm(2) and production of a 50 mm long spread out Bragg peak (SOBP) centered at 80 mm-depth in water...
May 29, 2017: Medical Physics
https://www.readbyqxmd.com/read/28554507/track-structure-model-of-microscopic-energy-deposition-by-protons-and-heavy-ions-in-segments-of-neuronal-cell-dendrites-represented-by-cylinders-or-spheres
#16
Murat Alp, Francis A Cucinotta
Changes to cognition, including memory, following radiation exposure are a concern for cosmic ray exposures to astronauts and in Hadron therapy with proton and heavy ion beams. The purpose of the present work is to develop computational methods to evaluate microscopic energy deposition (ED) in volumes representative of neuron cell structures, including segments of dendrites and spines, using a stochastic track structure model. A challenge for biophysical models of neuronal damage is the large sizes (> 100µm) and variability in volumes of possible dendritic segments and pre-synaptic elements (spines and filopodia)...
May 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/28547820/future-of-medical-physics-real-time-mri-guided-proton-therapy
#17
Bradley M Oborn, Stephen Dowdell, Peter E Metcalfe, Stuart Crozier, Radhe Mohan, Paul J Keall
With the recent clinical implementation of real-time MRI guided x-ray beam therapy (MRXT), attention is therapy (MRPT). MRI guidance for proton beam therapy is expected to offer a compelling improvement to the turning to the concept of combining real-time MRI guidance with proton beam therapy; MRI guided proton beam current treatment workflow which is warranted arguably more than for x-ray beam therapy. This argument is born out of the fact that proton therapy toxicity outcomes are similar to that of the most advanced IMRT treatments, despite being a fundamentally superior particle for cancer treatment...
May 26, 2017: Medical Physics
https://www.readbyqxmd.com/read/28529896/advances-in-radiotherapy-techniques-and-delivery-for-non-small-cell-lung-cancer-benefits-of-intensity-modulated-radiation-therapy-proton-therapy-and-stereotactic-body-radiation-therapy
#18
REVIEW
Tejan P Diwanji, Pranshu Mohindra, Melissa Vyfhuis, James W Snider, Chaitanya Kalavagunta, Sina Mossahebi, Jen Yu, Steven Feigenberg, Shahed N Badiyan
The 21st century has seen several paradigm shifts in the treatment of non-small cell lung cancer (NSCLC) in early-stage inoperable disease, definitive locally advanced disease, and the postoperative setting. A key driver in improvement of local disease control has been the significant evolution of radiation therapy techniques in the last three decades, allowing for delivery of definitive radiation doses while limiting exposure of normal tissues. For patients with locally-advanced NSCLC, the advent of volumetric imaging techniques has allowed a shift from 2-dimensional approaches to 3-dimensional conformal radiation therapy (3DCRT)...
April 2017: Translational Lung Cancer Research
https://www.readbyqxmd.com/read/28521117/neutron-spectral-fluence-measurements-using-a-bonner-sphere-spectrometer-in-the-development-of-the-ibnct-accelerator-based-neutron-source
#19
Akihiko Masuda, Tetsuro Matsumoto, Kenta Takada, Takahiro Onishi, Kohei Kotaki, Hidenori Sugimoto, Hiroaki Kumada, Hideki Harano, Takeji Sakae
The neutron spectral fluence of an accelerator-based neutron source facility for boron neutron capture therapy (BNCT) based on a proton linac and a beryllium target was evaluated by the unfolding method using a Bonner sphere spectrometer (BSS). A (3)He-proportional-counter-based BSS was used with weak beam during the development of the facility. The measured epithermal neutron spectra were consistent with calculations. The epithermal neutron intensity at the beam port was estimated and the results gave a numerical target for the enhancement of the proton beam intensity and will be used as reference data for measurements performed after the completion of the facility...
May 10, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28506520/the-evolving-role-of-proton-beam-therapy-for-sarcomas
#20
S Frisch, B Timmermann
As an alternative to conventional photon-based radiotherapy, radiation with protons is recognised to offer considerable advantages. Today, central nervous system tumours, various sarcomatous tumours, childhood cancer and head and neck tumours are commonly treated with proton therapy. This review evaluates current data from clinical and dosimetric trials on the treatment of selected sarcomatous tumours like rhabdomyosarcoma, osteosarcoma, chordoma, chondrosarcoma and Ewing sarcoma. Special considerations for paediatric tumours and future prospects of proton therapy are outlined...
May 12, 2017: Clinical Oncology: a Journal of the Royal College of Radiologists
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