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https://www.readbyqxmd.com/read/28645509/a-fast-and-reliable-method-for-daily-quality-assurance-in-spot-scanning-proton-therapy-with-a-compact-and-inexpensive-phantom
#1
Nicola Bizzocchi, Francesco Fracchiolla, Marco Schwarz, Carlo Algranati
In a radiotherapy center, daily quality assurance (QA) measurements are performed to ensure that the equipment can be safely used for patient treatment on that day. In a pencil beam scanning (PBS) proton therapy center, spot positioning, spot size, range, and dose output are usually verified every day before treatments. We designed, built, and tested a new, reliable, sensitive, and inexpensive phantom, coupled with an array of ionization chambers, for daily QA that reduces the execution times while preserving the reliability of the test...
June 20, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28644820/investigation-of-real-tissue-water-equivalent-path-lengths-using-an-efficient-dose-extinction-method
#2
Rongxiao Zhang, Esther Baer, Kyung-Wook Jee, Gregory C Sharp, Jay Flanz, Hsiao-Ming Lu
For proton therapy, an accurate conversion of CT HU to relative stopping power (RSP) is essential. Validation of the conversion based on real tissue samples is more direct than the current practice solely based on tissue substitutes and can potentially address variations over the population. Based on a novel dose extinction method, we measured water equivalent path lengths (WEPL) on animal tissue samples to evaluate the accuracy of CT HU to RSP conversion and potential variations over a population. A broad proton beam delivered a spread out Bragg peak to the samples sandwiched between a water tank and a 2D ion-chamber detector...
June 23, 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
#3
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/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/28625473/effect-of-dir-uncertainty-on-prostate-passive-scattering-proton-therapy-dose-accumulation
#5
Yoshitomo Abe, Noriyuki Kadoya, Kazuhiro Arai, Yoshiki Takayama, Takahiro Kato, Kanako Kimura, Takashi Ono, Tatsuya Nakamura, Hitoshi Wada, Yasuhiro Kikuchi, Keiichi Jingu
Deformable image registration (DIR) is important in dose accumulation. Currently, the impact of DIR-algorithm-associated uncertainties in proton therapy is unclear. Here, we quantify the effect of DIR uncertainties on prostate passive-scattering proton therapy (PSPT) dose accumulation. Ten patients with an intermediate risk for prostate cancer formerly treated by PSPT (PTV D95=78GyE) were studied. Dose distributions from all verification CT images (five images per patient) were warped and accumulated in the planning CT geometries with DIR...
June 15, 2017: Physica Medica: PM
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/28608702/a-proton-therapy-model-using-discrete-difference-equations-with-an-example-of-treating-hepatocellular-carcinoma
#8
Erin N Bodine, K Lars Monia
Proton therapy is a type of radiation therapy used to treat cancer. It provides more localized particle exposure than other types of radiotherapy (e.g., x-ray and electron) thus reducing damage to tissue surrounding a tumor and reducing unwanted side effects. We have developed a novel discrete difference equation model of the spatial and temporal dynamics of cancer and healthy cells before, during, and after the application of a proton therapy treatment course. Specifically, the model simulates the growth and diffusion of the cancer and healthy cells in and surrounding a tumor over one spatial dimension (tissue depth) and the treatment of the tumor with discrete bursts of proton radiation...
August 1, 2017: Mathematical Biosciences and Engineering: MBE
https://www.readbyqxmd.com/read/28595565/gold-nanoparticles-by-laser-ablation-for-x-ray-imaging-and-protontherapy-improvements
#9
Torrisi Lorenzo, Nancy Restuccia, Irene Paterniti
Gold nanoparticles, 5-20 nm in diameter, were generated with a pulsed Nd:YAG laser at 1010 W/cm2 at solution concentrations ranging between 1-100 mg/ml. Nanoparticles were characterized using optical absorbance, X-ray fluorescence, SEM, and TEM. Biocompatible nanoparticle solutions were injected by intravenously into the tail veins of mice followed by X-ray imaging using 20-45 keV photons to evaluate the uptake and the clearance by different organs of the nanoparticles. The incremental X-ray contrast imaging using gold nanoparticles was investigated and measured...
June 8, 2017: Recent Patents on Nanotechnology
https://www.readbyqxmd.com/read/28593931/performance-characterization-of-a-3d-liquid-scintillation-detector-for-discrete-spot-scanning-proton-beam-systems
#10
Chinmay D Darne, Fahed Alsanea, Daniel G 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 23, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28587051/evaluating-intensity-modulated-proton-therapy-relative-to-passive-scattering-proton-therapy-for-increased-vertebral-column-sparing-in-craniospinal-irradiation-in-growing-pediatric-patients
#11
Drosoula Giantsoudi, Joao Seco, Bree R Eaton, F Joseph Simeone, Hanne Kooy, Torunn I Yock, Nancy J Tarbell, Thomas F DeLaney, Judith Adams, Harald Paganetti, Shannon M MacDonald
PURPOSE: At present, proton craniospinal irradiation (CSI) for growing children is delivered to the whole vertebral body (WVB) to avoid asymmetric growth. We aimed to demonstrate the feasibility and potential clinical benefit of delivering vertebral body sparing (VBS) versus WVB CSI with passively scattered (PS) and intensity modulated proton therapy (IMPT) in growing children treated for medulloblastoma. METHODS AND MATERIALS: Five plans were generated for medulloblastoma patients, who had been previously treated with CSI PS proton radiation therapy: (1) single posteroanterior (PA) PS field covering the WVB (PS-PA-WVB); (2) single PA PS field that included only the thecal sac in the target volume (PS-PA-VBS); (3) single PA IMPT field covering the WVB (IMPT-PA-WVB); (4) single PA IMPT field, target volume including thecal sac only (IMPT-PA-VBS); and (5) 2 posterior-oblique (-35°, +35°) IMPT fields, with the target volume including the thecal sac only (IMPT2F-VBS)...
May 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28587003/photon-volumetric-modulated-arc-therapy-versus-intensity-modulated-proton-therapy-versus-intensity-modulated-carbon-ion-therapy-in-the-delivery-of-hypofractionated-thoracic-radiation-therapy
#12
A Chi, L C Lin, S Wen, H Yan, W C Hsi
No abstract text is available yet for this article.
May 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28586979/impact-of-unfavorable-factors-on-outcomes-among-inoperable-stage-ii-iv-non-small-cell-lung-cancer-patients-treated-with-proton-therapy
#13
H J Zhu, R C Nichols, R H Henderson, C G Morris, S Flampouri, D C Pham, C L Klassen, A A Bajwa, J D Cury, B S Hoppe
No abstract text is available yet for this article.
May 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28586972/reirradiation-of-thoracic-cancers-with-intensity-modulated-proton-therapy
#14
J C Ho, Q N Nguyen, H Li, P K Allen, X Zhang, X R Zhu, D R Gomez, S H Lin, M T Gillin, R U Komaki, Z Liao, S M Hahn, J Y Chang
No abstract text is available yet for this article.
May 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28586953/dry-eye-syndrome-after-proton-therapy-of-ocular-melanomas
#15
Juliette Thariat, Celia Maschi, Sara Lanteri, Marie Laure Peyrichon, Stephanie Baillif, Joel Herault, Julia Salleron, Jean Pierre Caujolle
PURPOSE: To investigate whether proton therapy (PT) performs safely in superotemporal melanomas, in terms of risk of dry-eye syndrome (DES). METHODS AND MATERIALS: Tumor location, DES grade, and dose to ocular structures were analyzed in patients undergoing PT (2005-2015) with 52 Gy (prescribed dose, not accounting for biologic effectiveness correction of 1.1). Prognostic factors of DES and severe DES (sDES, grades 2-3) were determined with Cox proportional hazard models...
May 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28582266/a-beam-monitoring-and-validation-system-for-continuous-line-scanning-in-proton-therapy
#16
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
#17
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/28569997/impact-of-spot-charge-inaccuracies-in-impt-treatments
#18
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/28562200/underutilization-of-proton-therapy-in-the-treatment-of-pediatric-central-nervous-system-tumors-an-analysis-of-the-national-cancer-database
#19
Atif J Khan, Benjamin H Kann, Wilbur Pan, Richard Drachtman, Ken Roberts, Rahul R Parikh
No abstract text is available yet for this article.
August 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28549794/intensity-modulated-proton-therapy-and-osteoradionecrosis-in-oropharyngeal-cancer
#20
Wencheng Zhang, Xiaodong Zhang, Pei Yang, Pierre Blanchard, Adam S Garden, Brandon Gunn, C David Fuller, Mark Chambers, Katherine A Hutcheson, Rong Ye, Stephen Y Lai, Mohamed Abdallah Sherif Radwan, X Ron Zhu, Steven J Frank
PURPOSE: We compared mandibular doses and osteoradionecrosis in patients with oropharyngeal cancer after intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT). METHODS AND MATERIALS: We identified 584 patients who received definitive radiotherapy for oropharyngeal cancer from January 2011 through June 2014 at MD Anderson Cancer Center (534 IMRT and 50 IMPT). The dosimetric variables and osteoradionecrosis were compared with Chi-square test or Fisher's exact test...
May 23, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
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