نتایج جستجو برای: proton therapy bragg peak
تعداد نتایج: 854850 فیلتر نتایج به سال:
Introduction: High-energy beams of protons offer significant advantages for the treatment of deepseated local tumors. Their physical depth-dose distribution in tissue is characterized by a small entrance dose and a distinct maximum -Bragg peak- near the end of range with a sharp fall-off at the distal edge. Alongside its advantages there are some point that they need to meticul...
Introdution: Today, the Advantages of radiation therapy by charged particles is indicated for the treatment of cancerous. During the passing of proton beam in the body tissues, secondary particles produce, which penetrate to the body healthy tissues and cause damage. The aim of this research was calculating the Spread out Bragg Peak for covering the breast cancer and investigating arrived dose ...
Introduction: Proton therapy is newer therapeutic method for early stage breast cancer. Proton beams release most of their energy in the Bragg peak and then will be a rapid decline in their end. When protons interact with matter, produce secondary particles like neutrons and gammas, and these unwanted radiation has no beneficial effect and also is believed to increase the risk ...
In this research, in order to improve our calculations in treatment planning for proton radiotherapy of ocular melanoma, we improved our human eye phantom planning system in GEANT4 toolkit. Different analytical models have investigated the creating of Spread Out Bragg Peak (SOBP) in the tumor area. Bortfeld’s model is one of the most important analytical methods. Using convolution method, a new...
In radiation therapy, ions heavier than proton have more biological advantages than a proton beam. Recently, ion helium has been considered due to high linear energy transfer (LET) to the medium and a higher relative biological effect (RBE). To design the spread-out Bragg peak (SOBP) of biological dose for radiation with any type of ion, we need exact values of RBE, which is dependent to dose, ...
Proton therapy is a common form of external radiation therapy based on the manipulation of Bragg peak of this beam, it can treat the tumor by delivering high levels of doses to it, while protecting surrounding healthy tissues against radiation. In this work, the dose distribution of proton and secondary particles such as neutrons, photons, electrons and positrons in gastric cancer proton therap...
Due to their Bragg peak, proton beams are capable of delivering a targeted dose of radiation to a narrow volume, but range uncertainties currently limit their accuracy. One promising beam characterization technique, protoacoustic range verification, measures the acoustic emission generated by the proton beam. We simulated the pressure waves generated by proton radiation passing through water. W...
PURPOSE Laser-based accelerated proton beams are unsuitable for clinical use because of their broad energy spectra. For this reason, it is essential to employ an energy selection system (ESS). The purpose of this study is to determine optimum parameters of the ESS which uses a varying magnetic field to generate Bragg-peak. METHODS We simulated an accelerated proton beams using radiation press...
Background: The advantages of proton beam in radiation therapy- like small lateral scattering as well as absence of exit dose tail in the organs which are after the tumor- make it capable of delivering more treatment doses to the target and much lesser to the critical tissues near it. Materials and Methods: In this study, the Monte Carlo MCNPX code has been used to simulate a slab head phantom ...
There are many unknowns in the radiobiology of proton beams and other particle beams. We describe the development and testing of an image-guided low-energy proton system optimized for radiobiological research applications. A 50 MeV proton beam from an existing cyclotron was modified to produce collimated beams (as small as 2 mm in diameter). Ionization chamber and radiochromic film measurements...
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