keyword
MENU ▼
Read by QxMD icon Read
search

Radiation, proton therapy

keyword
https://www.readbyqxmd.com/read/28079196/ultra-fast-charge-migration-competes-with-proton-transfer-in-the-early-chemistry-of-h2o%C3%AB
#1
Furong Wang, Uli Schmidhammer, Aurélien de La Lande, Mehran Mostafavi
Oxidation by the ultra-short lived radical cation of water, H2O˙(+), can potentially take place at the interface of water and numerous heterogeneous systems involved in radiation therapy, energy and environmental industries. The oxidation processes induced by H2O˙(+) can be mimicked in highly concentrated solutions where the nearest neighbors of H2O˙(+) may be molecules other than water. The reactivity of H2O˙(+) and D2O˙(+) is probed in hydrogenated and deuterated sulfuric acid solutions of various concentrations...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28077128/treatment-planning-comparison-of-impt-vmat-and-4%C3%AF-radiotherapy-for-prostate-cases
#2
Angelia Tran, Jingjing Zhang, Kaley Woods, Victoria Yu, Dan Nguyen, Gary Gustafson, Lane Rosen, Ke Sheng
BACKGROUND: Intensity-modulated proton therapy (IMPT), non-coplanar 4π intensity-modulated radiation therapy (IMRT), and volumetric-modulated arc therapy (VMAT) represent the most advanced treatment methods based on heavy ion and X-rays, respectively. Here we compare their performance for prostate cancer treatment. METHODS: Ten prostate patients were planned using IMPT with robustness optimization, VMAT, and 4π to an initial dose of 54 Gy to a clinical target volume (CTV) that encompassed the prostate and seminal vesicles, then a boost prescription dose of 25...
January 11, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28068248/clinical-implementation-of-dual-energy-ct-for-proton-treatment-planning-on-pseudo-monoenergetic-ct-scans
#3
Patrick Wohlfahrt, Christian Möhler, Volker Hietschold, Stefan Menkel, Steffen Greilich, Mechthild Krause, Michael Baumann, Wolfgang Enghardt, Christian Richter
PURPOSE: To determine whether a standardized clinical application of dual-energy computed tomography (DECT) for proton treatment planning based on pseudomonoenergetic CT scans (MonoCTs) is feasible and increases the precision of proton therapy in comparison with single-energy CT (SECT). METHODS AND MATERIALS: To define an optimized DECT protocol, CT scan settings were analyzed experimentally concerning beam hardening, image quality, and influence on the heuristic conversion of CT numbers into stopping-power ratios (SPRs) and were compared with SECT scans with identical CT dose...
February 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28068231/establishing-evidence-based-indications-for-proton-therapy-an-overview-of-current-clinical-trials
#4
Mark V Mishra, Sameer Aggarwal, Soren M Bentzen, Nancy Knight, Minesh P Mehta, William F Regine
PURPOSE: To review and assess ongoing proton beam therapy (PBT) clinical trials and to identify major gaps. METHODS AND MATERIALS: Active PBT clinical trials were identified from clinicaltrials.gov and the World Health Organization International Clinical Trials Platform Registry. Data on clinical trial disease site, age group, projected patient enrollment, expected start and end dates, study type, and funding source were extracted. RESULTS: A total of 122 active PBT clinical trials were identified, with target enrollment of >42,000 patients worldwide...
February 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28048906/su-f-t-666-molecular-targeted-gold-nanorods-enhances-the-rbe-of-proton-therapy
#5
A Khoo, N Sahoo, S Krishnan, P Diagaradjane
PURPOSE: In recent years, proton beam radiation therapy (PBRT) has gained significant attention in the treatment of tumors in anatomically complex locations. However, the therapeutic benefit of PBRT is limited by a relative biological effectiveness (RBE) of just 1.1. The purpose of this study is to evaluate whether this limitation can be overcome by artificially enhancing the RBE using molecular-targeted gold nanorods (GNRs). METHODS: Molecular-targeting of GNRs was accomplished using Cetuximab (antibody specific to epidermal growth factor receptor that is over-expressed in tumors) conjugated GNRs (cGNRs) and their binding affinity to Head and Neck cancer cells was confirmed using dark field microscopy and Transmission Electron Microscopy (TEM)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048899/we-fg-202-09-voxel-level-analysis-of-adverse-treatment-response-in-pediatric-patients-treated-for-ependymoma-with-passive-scattering-proton-therapy
#6
C Peeler, D Mirkovic, U Titt, D Grosshans, R Mohan
PURPOSE: We identified patients treated for ependymoma with passive scattering proton therapy who subsequently developed treatment-related imaging changes on MRI. We sought to determine if there is any spatial correlation between imaged response, dose, and LET. METHODS: A group of 14 patients treated for ependymoma were identified as having post-treatment MR imaging changes observable as T2-FLAIR hyperintensity with or without enhancement on T1 post-contrast sequences...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048748/su-f-t-159-monte-carlo-simulation-studies-of-three-dimensional-dose-distribution-for-polymer-gel-dosimeter-and-radiochromic-gel-dosimeter-in-a-proton-beam
#7
M Park, G Kim, H Jung, S Park, S Park, Y Ji, J Yun
PURPOSE: The purpose of this simulation study is to evaluate the proton detectability of gel dosimeters, and estimate the three-dimensional dose distribution of protons in the radiochromic gel and polymer gel dosimeter compared with the dose distribution in water. METHODS: The commercial composition ratios of normoxic polymer gel and LCV micelle radiochromic gel were included in this simulation study. The densities of polymer and radiochromic gel were 1.024 and 1...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048714/su-f-t-137-out-of-beam-dose-for-a-compact-double-scattering-proton-beam-therapy-system
#8
M Islam, S Ahmad, H Jin
PURPOSE: The out-of-beam dose is important for understanding the peripheral dose in radiation therapy. In proton radiotherapy, the study of out-of-beam dose is scarce and the treatment planning system (TPS) based on pencil beam algorithm cannot accurately predict the out-of-beam dose. This study investigates the out-of-beam dose for the single-room Mevion S250 double scattering proton therapy system using experimentally measured and treatment planning software generated data. The results are compared with those reported for conventional photon beam therapy...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048713/su-f-t-209-multicriteria-optimization-algorithm-for-intensity-modulated-radiation-therapy-using-pencil-proton-beam-scanning
#9
C Beltran, H Kamal
PURPOSE: To provide a multicriteria optimization algorithm for intensity modulated radiation therapy using pencil proton beam scanning. METHODS: Intensity modulated radiation therapy using pencil proton beam scanning requires efficient optimization algorithms to overcome the uncertainties in the Bragg peaks locations. This work is focused on optimization algorithms that are based on Monte Carlo simulation of the treatment planning and use the weights and the dose volume histogram (DVH) control points to steer toward desired plans...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048662/su-f-t-206-proton-treatment-techniques-for-posterior-fossa-tumors-consequences-for-let-and-dose-volume-parameters-for-the-brainstem-and-organs-at-risk
#10
D Giantsoudi, J Adams, S MacDonald, H Paganetti
PURPOSE: In proton radiation therapy of posterior fossa tumors, to spare other sensitive structures, the preferred beam geometry results in placing the treatment field distal edge within or just beyond the brainstem, including in at least partially in the treatment volume. Concerns for brainstem toxicity are increased and a controversy exists as to weather the beam's distal edge should be placed within the brainstem or beyond it, to avoid elevated linear energy transfer (LET) and relative biological effectiveness (RBE) within the brainstem...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048658/su-f-t-166-on-the-nature-of-the-background-visible-light-observed-in-fiber-optic-dosimetry-of-proton-beams
#11
A Darafsheh, R Taleei, A Kassaee, J Finlay
PURPOSE: The nature of the background visible light observed during fiber optic dosimetry of proton beams, whether it is due to Cherenkov radiation or not, has been debated in the literature recently. In this work, experimentally and by means of Monte Carlo simulations, we shed light on this problem and investigated the nature of the background visible light observed in fiber optics irradiated with proton beams. METHODS: A bare silica fiber optics was embedded in tissue-mimicking phantoms and irradiated with clinical proton beams with energies of 100-225 MeV at Roberts Proton Therapy Center...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048626/su-f-t-212-a-comparison-of-treatment-strategies-for-intracranial-stereotactic-radiosurgery
#12
T Lamberton, J Slater, A Wroe
PURPOSE: Stereotactic radiosurgery is an effective and noninvasive treatment for intracranial lesions that uses highly focused radiation beams in a single treatment fraction. The purpose of this study is to investigate the dosimetric differences between the treatment brain metastasis with a proton beam vs. intensity modulated radiation therapy (IMRT). METHODS: Ten separate brain metastasis targets where chosen and treatment plans were created for each, using three different strategies: custom proton beam shaping devices, standardized proton beam shaping devices, and IMRT...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048590/we-ab-brb-03-real-time-volumetric-scintillation-dosimetry-for-radiation-therapy
#13
S Beddar
: Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048551/we-fg-brb-02-spatial-mapping-of-the-rbe-of-scanned-particle-beams
#14
D Grosshans
: The physical pattern of energy deposition and the enhanced relative biological effectiveness (RBE) of protons and carbon ions compared to photons offer unique and not fully understood or exploited opportunities to improve the efficacy of radiation therapy. Variations in RBE within a pristine or spread out Bragg peak and between particle types may be exploited to enhance cell killing in target regions without a corresponding increase in damage to normal tissue structures. In addition, the decreased sensitivity of hypoxic tumors to photon-based therapies may be partially overcome through the use of more densely ionizing radiations...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048549/th-a-204-01-part-i-key-data-for-ionizing-radiation-dosimetry
#15
S Seltzer
: The ICRU is currently finalizing a report on key data for radiation dosimetry. This multi-year review has resulted in a number of recommendations regarding "fundamental" data that are used in dosimetry related to radiation therapy. This educational session will explain the background for the ICRU committee's work, the content and conclusions of the report and the impact on outputs, including NIST primary standards, ADCL calibration coefficients and clinical reference dosimetry. Parameters and beam modalities potentially affected by this report include: The mean excitation energy, I, for graphite, air, and water, The average energy required to create an ion pair in dry air (commonly referred to as W/e), The uncertainty in the determination of air kerma in kV x-rays The absolute value of Co-60 and Cs-137 primary standards and the dissemination of calibration coefficients, The determination of air kerma strength for Ir-192 HDR brachytherapy sources Ion chamber kQ factors for linac MV beams Ion chamber kQ factors for proton beams...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048472/tu-h-campus-jep3-04-factors-predicting-a-need-for-treatment-replanning-with-proton-radiotherapy-for-lung-cancer
#16
C Teng, G Janssens, C Ainsley, B Teo, G Valdes, B Burgdorf, A Berman, W Levin, Y Xiao, L Lin, P Gabriel, C Simone, T Solberg
PURPOSE: Proton dose distribution is sensitive to tumor regression and tissue and normal anatomy changes. Replanning is sometimes necessary during treatment to ensure continue tumor coverage or avoid overtreatment of organs at risk (OARs). We investigated action thresholds for replanning and identified both dosimetric and non-dosimetric metrics that would predict a need for replan. METHODS: All consecutive lung cancer patients (n = 188) who received definitive proton radiotherapy and had more than two evaluation CT scans at the Roberts Proton Therapy Center (Philadelphia, USA) from 2011 to 2015 were included in this study...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048445/su-c-207a-07-cumulative-18f-fdg-uptake-histogram-relative-to-radiation-dose-volume-histogram-of-lung-after-imrt-or-pspt-and-their-association-with-radiation-pneumonitis
#17
N Shusharina, Z Liao, R Mohan, N Choi, T Bortfeld
PURPOSE: To determine whether the difference in cumulative 18F-FDG uptake histogram of lung treated with either IMRT or PSPT is associated with radiation pneumonitis (RP) in patients with inoperable stage II and III NSCLC. METHODS: We analyzed 24 patients from a prospective randomized trial to compare IMRT (n=12) with vs. PSPT (n=12) for inoperable NSCLC. All patients underwent PET-CT imaging between 35 and 88 days post-therapy. Post-treatment PET-CT was aligned with planning 4D CT to establish a voxel-to-voxel correspondence between post-treatment PET and planning dose images...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048410/su-f-t-682-in-vivo-simulation-of-the-relative-biological-effectiveness-in-proton-therapy-using-a-monte-carlo-method
#18
H Oesten, S Loeck, S Helmbrecht, F Tillner, P Wohlfahrt, J Schuemann, A Luehr
PURPOSE: In proton therapy, the relative biological effectiveness (RBE) - compared with conventional photon therapy - is routinely set to 1.1. However, experimental in vitro studies indicate evidence for the variability of the RBE. To clarify the impact on patient treatment, investigation of the RBE in a preclinical case study should be performed. METHODS: The Monte Carlo software TOPAS was used to simulate the radiation field of an irradiation setup at the experimental beamline of the proton therapy facility (OncoRay) in Dresden, Germany...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048360/mo-b-201-03-mri-guided-tracking-and-gating
#19
O Green
: The motion management in stereotactic body radiation therapy (SBRT) is a key to success for a SBRT program, and still an on-going challenging task. A major factor is that moving structures behave differently than standing structures when examined by imaging modalities, and thus require special considerations and employments. Understanding the motion effects to these different imaging processes is a prerequisite for a decent motion management program. The commonly used motion control techniques to physically restrict tumor motion, if adopted correctly, effectively increase the conformity and accuracy of hypofractionated treatment...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048337/we-fg-202-03-quantitative-ct-based-analysis-to-assess-lung-injury-following-proton-radiotherapy
#20
T Underwood, C Grassberger, H Willers, S MacDonald, R Jimenez, H Paganetti
PURPOSE: Relative to photon alternatives, the increased dose-conformity associated with proton therapy is expected to reduce the extent of radiation-induced lung toxicity. However, analysis of follow-up data is yet to be published in this area. In this study we retrospectively analyzed late-phase HU changes for proton therapy cohorts of chest wall and lung patients. METHODS: From our institution's register of patients treated using double-scattered protons, all chest wall and stereotactic lung cases (treated 2011-2012 and 2008-2014 respectively) were initially considered...
June 2016: Medical Physics
keyword
keyword
23521
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"