نتایج جستجو برای: proton therapy bragg peak

تعداد نتایج: 854850  

Journal: :Physics in medicine and biology 2008
Yuanshui Zheng Jonas Fontenot Phil Taddei Dragan Mirkovic Wayne Newhauser

Stray neutron exposures pose a potential risk for the development of secondary cancer in patients receiving proton therapy. However, the behavior of the ambient dose equivalent is not fully understood, including dependences on neutron spectral fluence, radiation weighting factor and proton treatment beam characteristics. The objective of this work, therefore, was to estimate neutron exposures r...

Journal: :Physical review letters 2008
M Laver E M Forgan A B Abrahamsen C Bowell Th Geue R Cubitt

We describe the use of reverse Monte Carlo refinement to extract structural information from angle-resolved data of a Bragg peak. Starting with small-angle neutron scattering data, the positional order of an ensemble of flux lines in superconducting Nb is revealed. We discuss the uncovered correlation functions in the light of topical theories, in particular, the "Bragg glass" paradigm.

Journal: :Crystals 2021

The simultaneous measurement of two Bragg reflections by coherent X-ray diffraction is demonstrated on a twinned Au crystal, which was prepared the solid-state dewetting 30 nm thin gold film sapphire substrate. crystal oriented goniometer so that lattice planes fulfill condition at same time. 111 and 200 peaks were measured simultaneously scanning energy incident beam recording patterns with tw...

2009
WenJun Zheng GuangTao Fei Biao Wang Li De Zhang

We have successfully prepared anodized alumina membrane distributed Bragg reflector (DBR) using electrochemical anodization method. The transmission peak of this distributed Bragg reflector could be easily and effectively modulated to cover almost any wavelength range of the whole visible spectrum by adjusting anodization temperature.

2014
Boualem Hammouda

It is common practice to assume that Bragg scattering peaks have Gaussian shape. The Gaussian shape function is used to perform most instrumental smearing corrections. Using Monte Carlo ray tracing simulation, the resolution of a realistic small-angle neutron scattering (SANS) instrument is generated reliably. Including a single-crystal sample with large d-spacing, Bragg peaks are produced. Bra...

Journal: :Frontiers in oncology 2016
Mario Pietro Carante Francesca Ballarini

A biophysical model of radiation-induced cell death and chromosome aberrations [called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA)] was further developed and applied to therapeutic protons. The model assumes a pivotal role of DNA cluster damage, which can lead to clonogenic cell death following three main steps: (i) a DNA "cluster lesion" (CL) produces two independent...

2000
B. Marchand D. Prieels B. Bauvir Ion Beam

Particles are used in medical application for cancer treatment. Radiotherapy aims to deliver a high dose in a well-defined target volume while sparing the healthy surrounding tissues. Compared to the conventional radiotherapy (X-ray), protons show superior clinical performances thanks to their inherent depth dose characteristic (Bragg peak). In proton therapy, several techniques can be used to ...

Journal: :Frontiers in Physics 2021

In Charged Particle Therapy (PT) proton or 12 C beams are used to treat deep-seated solid tumors exploiting the advantageous characteristics of charged particles energy deposition in matter. For such projectiles, maximum dose is released at end beam range, Bragg peak region, where tumour located. However, nuclear interactions nuclei with patient tissues can induce fragmentation projectiles and/...

2002
Hideyuki Harada Shigeyuki Murayama

This review summarizes the past and present status of proton beam therapy (PBT) for lung cancer. PBT has a unique characteristic called the Bragg peak that enables a reduction in the dose of normal tissue around the tumor, but is sensitive to the uncertainties of density changes. The heterogeneity in electron density for thoracic lesions, such as those in the lung and mediastinum, and tumor mov...

2017
Mohammad Javad Tahmasebi Birgani Nahid Chegeni Mansour Zabihzadeh Marziyeh Tahmasbi

Background Integrated proton therapy - MRI systems are capable of delivering high doses to the target tissues near sensitive organs and achieve better therapeutic results; however, the applied magnetic field for imaging, influences the protons path, changes the penetration depth and deflects the particles, laterally, leading to dose distribution variations. Objective To determine the effects ...

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