scholarly journals Theoretical Study for the Calculation of Proton Range in Human Body Tissues

2021 ◽  
pp. 3392-3399
Author(s):  
Shaima M. Hadi ◽  
Bashair M. Saied
Keyword(s):  
Bragg Peak ◽  
Theoretical Study ◽  
Absorbed Dose ◽  
Proton Radiotherapy ◽  
Normal Tissues ◽  
Matlab Program ◽  
Proton Interaction ◽  
Body Tissues ◽  
Maximum Penetration Depth ◽  
Maximum Penetration

     The main rationale for using charged particles in radiation therapy is the strong rise of energy loss (deposited dose) with maximum penetration depth ( Bragg peak) and rapid dose deposited  behind the peak. Thus, a large dose can be  applied to a deep seated tumor, with saving the surrounding normal tissues . Proton radiotherapy is nowadays an established method in the management of cancer diseases, although its availability is still limited to a few specialized centers. In this study, the range and the stopping power for proton interaction  in the skeleton  and intestine tissues, for an energy range from 0.01 to 300 MeV, was studied. The numerical calculations and analyses of Bethe  Ziegler, along with CASP and SRIM software programs, were applied using Matlab program. The absorbed dose and the Bragg peak were calculated and presented as tables and figures .

Theoretical study of the influence of a heterogeneous activity distribution on intratumoral absorbed dose distribution

2004 ◽  
Vol 32 (1) ◽  
pp. 200-208 ◽  
Author(s):  
Ande Bao ◽  
Xia Zhao ◽  
William T. Phillips ◽  
F. Ross Woolley ◽  
Randal A. Otto ◽  
...  
Keyword(s):  
Dose Distribution ◽  
Theoretical Study ◽  
Absorbed Dose ◽  
Activity Distribution

scholarly journals Theoretical Study on Proton Diffusivity in Y-Doped BaZrO3 with Realistic Dopant Configurations

2020 ◽  
Author(s):  
Takeo Fujii ◽  
Kazuaki Toyoura ◽  
Tetsuya Uda ◽  
Shusuke Kasamatsu
Keyword(s):  
First Principles ◽  
Theoretical Study ◽  
Site Effect ◽  
Barium Zirconate ◽  
Proton Proton ◽  
Potential Wells ◽  
Proton Interaction ◽  
Master Equation Approach ◽  
Replica Exchange Monte Carlo ◽  
Random Configuration

We theoretically revisit the proton diffusivity in yttrium-doped barium zirconate (Y-doped BaZrO<sub>3</sub>) with realistic dopant configurations under processing conditions. In a recent study employing the replica exchange Monte Carlo method, the equilibrium Y configurations at typical sintering temperatures were shown to deviate from the random configuration assumed in earlier theoretical studies. In the present study, we took this observation into account and evaluated the effect of the Y configuration on the proton diffusivity. Using the master equation approach based on local diffusion barriers calculated from first principles, the proton diffusivities under realistic Y configurations were estimated to be higher than those in the random configuration. This is explained by the fact that realistic Y configurations have fewer trap sites with deep potential wells compared to the random configuration due to the isolation trend of Y dopants. In addition, the effects of proton-proton interaction and the abundance of preferential conduction pathways are discussed; it is found that both are relatively minor factors compared to the trap site effect in determining the dependence of the proton diffusivity on the Y configurations.<br>

Design and Tests of a Multi-pin Flexible Seedling Pick-up Gripper for Automatic Transplanting

2019 ◽  
Vol 35 (6) ◽  
pp. 949-957 ◽  
Author(s):  
Luhua Han ◽  
Francis Kumi ◽  
Hanping Mao ◽  
Jianping Hu
Keyword(s):  
Control System ◽  
Penetration Depth ◽  
Working Pressure ◽  
Pneumatic Control ◽  
Position Detection ◽  
Maximum Penetration Depth ◽  
Timely Response ◽  
Plug Seedling ◽  
Maximum Penetration ◽  
Push Out

HighlightsA multi-pin flexible pick-up gripper with a four-jaw chuck having four pick-up pins has been developed.The gripper can effectively grasp, hold and release plug seedlings with low damages to the plants and the root soil.Based on a typical on-off control and cylinder stroke position detection, the control system for timely response was designed to automate the process of picking up and releasing seedlings.Abstract. A multi-pin flexible seedling pick-up gripper for automatic transplanting was developed and evaluated. The gripper having a four-jaw chuck mainly consists of a parallel-type air gripper with four fingers, four fork frames, four cylinder fingers, and several connecting/supporting parts. The air gripper moves to open and close the cylinder fingers, and the cylinder fingers each having a flexible pin grasp and release the seedling. When the pick-up gripper extracts seedlings from the tray cells, its four cylindrical fingers push out four pick-up pins to penetrate deep into the root soil and then close, making the pick-up pins to firmly hold the root soil for lifting. When the pick-up gripper releases seedlings, its fingers open, making the pick-up pins loosen the root soil and then pull back for discharging. An electrical and pneumatic control system was designed to coordinate the execution of each action. The pick-up gripper attached to a robotic manipulator was tested on a range of plug seedling transplanting parameters and conditions. The results showed that penetration depth, seedling species, and the interaction of working pressure and seedling species significantly influenced the successful automatic transplanting. On the whole, the seedling integrity ratio in automatic transplanting was found to be up to 93.37%. For optimum performance of the device in transplanting seedlings, the pick-up pins of the multi-pin gripper need to grasp the maximum amount of root soil at their maximum penetration depth. Keywords: Gripper, Flexible, Multi-pin, Seedlings, Transplanting.

An Empirical Correlation for Maximum Penetration Depth of a Particle Impacting on a Free Surface at its Critical Velocity Condition

2011 ◽  
Vol 361-363 ◽  
pp. 320-323 ◽  
Author(s):  
Dong Mei Liu ◽  
Geoffrey Michael Evans ◽  
Qing Lin He
Keyword(s):  
Penetration Depth ◽  
Critical Condition ◽  
High Speed ◽  
Least Squares Method ◽  
Density Ratio ◽  
Video Camera ◽  
Empirical Correlation ◽  
Liquid Density ◽  
Maximum Penetration Depth ◽  
Maximum Penetration

Film flotation is a process which consumes much lower energy than mechanical cells. The extended film flotation technique is to separate mineral mixtures by different critical impact velocities. In this study the maximum penetration depth of a particle at its critical condition was investigated experimentally and theoretically. Experiments were performed using spherical glass beads of different diameters and hydrophobicities and different liquids. The penetration depth at critical condition was recorded and measured using high speed video camera. Buckingham’s PI theorem was applied to analyse the dimensionless groups, and then an empirical correlation for penetration depth was obtained by partial least squares method. It was found that the prediction results of the empirical equation were in good agreement with the measurements. Also, the influence factors were analysed. It was noticed that the hydrophobicities of particle and particle-liquid density ratio had most significant effects on the penetration depth.

Electrochemical and Mechanical Characterization of TiO2 Nanotubes Obtained by Anodic Oxidation at High Voltage

2016 ◽  
Vol 1815 ◽  
Author(s):  
S. Mejía Sintillo ◽  
C. Cuevas Arteaga ◽  
R. Ma. Melgoza ◽  
P. Mijailova Nacheva
Keyword(s):  
Mechanical Characterization ◽  
Chemical Characterization ◽  
Xrd Analysis ◽  
Electrochemical Stability ◽  
Electrochemical Anodization ◽  
Electrochemical Tests ◽  
Flat Surfaces ◽  
Deformation Curves ◽  
Maximum Penetration Depth ◽  
Maximum Penetration

ABSTRACTThe array of the TiO2 nanotubular films, also called one-dimensional nanostructures is carried out by electrochemical anodization tests, for which, titanium sheets were used with a high purity (99.7% and 0.25 mm thickness) in a solution of deionized water and glycerol (50:50 vol.%) + 0.27M NH4F applying a voltage of 20V. Electrochemical tests were performed at an anodization time of 2:30 hours and 3:30 hours. For the tests mirror polished foils and unpolished foils with flat surfaces to achieve better uniform arrays during the anodic growth of nanotubes were used. After anodizing, samples were observed in the scanning electron microscope (SEM) to determine the geometry and morphology of the films. Also, potentiodynamic polarization curves were performed for samples crystallized at 600 °C and 450 °C (polished and unpolished) to determine the electrochemical stability of the films, which were presented at two aqueous solutions: 1M of Na2SO4 (pH= 6.7) and 1M Na2SO4 + H2SO4 (pH= 3.2). Mechanical characterization was also performed by nanoindentation technique through the application of loading/unloaings of: (1, 2.5, 5, 10 mN). Chemical characterization was performed using XRD analysis, with the aim to determine the crystalline phases formed in the films crystallized at 450 °C and 600 °C. The electrochemical characterization showed that the TiO2 nanotubular film obtained by mirror polished and crystallized at 600 °C showed better electrochemical stability. Nanoindentation tests showed deformation curves, and the parameters such as hardness, Vickers hardness, elastic modulus and the maximum penetration depth were determined as mechanical parameters.

scholarly journals Dosimetric Deviations of Bragg-Peak Position Shifts in Uniform Magnetic Fields for Magnetic Resonance Imaging-Guiding Proton Radiotherapy: A Monte Carlo Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaowa Wang ◽  
Hailun Pan ◽  
Qinqin Cheng ◽  
Xufei Wang ◽  
Wenzhen Xu
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Analytical Model ◽  
Bragg Peak ◽  
Peak Position ◽  
Proton Radiotherapy ◽  
3.0 Tesla ◽  
Proton Track ◽  
Mc Simulation ◽  
Dose Levels

Objective: To investigate dosimetric deviations in scanning protons for Bragg-peak position shifts, which were caused by proton spiral tracks in an ideal uniform field of magnetic resonance (MRI) imaging-guided proton radiotherapy (MRI-IGPRT).Methods: The FLUKA Monte-Carlo (MC) code was used to simulate the spiral tracks of protons penetrating water with initial energies of 70–270 MeV under the influence of field strength of 0.0–3.0 Tesla in commercial MRI systems. Two indexes, lateral shift (marked as WD) perpendicular to the field and a penetration-depth shift (marked as ΔDD) along the beam path, were employed for the Bragg-peak position of spiral proton track analysis. A comparison was performed between MC and classical analytical model to check the simulation results. The shape of the 2D/3D dose distribution of proton spots at the depth of Bragg-Peak was also investigated. The ratio of Gaussian-fit value between longitudinal and transverse major axes was used to indicate the asymmetric index. The skewness of asymmetry was evaluated at various dose levels by the radius ratio of circumscribed and inscribed circles by fitting a semi-ellipse circle of 2D distribution.Results: The maximum of WD deflection is 2.82 cm while the maximum of shortening ΔDD is 0.44 cm for proton at 270 MeV/u under a magnetic field of 3.0 Tesla. The trend of WD and ΔDD from MC simulation was consistent with the analytical model, which means the reverse equation of the analytical model can be applied to determine the proper field strength of the magnet and the initial energy of the proton for the planned dose. The asymmetry of 2D/3D dose distribution under the influence of a magnetic field was increased with higher energy, and the skewness of asymmetry for one proton energy at various dose levels was also increased with a larger radius, i.e., a lower dose level.Conclusions: The trend of the spiral proton track under a uniform magnetic field was obtained in this study using either MC simulation or the analytical model, which can provide an optimized and planned dose of the proton beam in the clinical application of MRI-IGPRT.

scholarly journals Oncology and palliative care

2019 ◽  
pp. 125-208
Keyword(s):  
Palliative Care ◽  
Side Effects ◽  
Life Expectancy ◽  
Industrialized Countries ◽  
Normal Tissues ◽  
Body Tissues ◽  
Biological Treatments ◽  
The Common ◽  
Oncology Practice ◽  
The Uk

This chapter provides an overview of current oncology practice as it pertains to palliative care. It covers the care of patients undergoing oncological interventions including some of the newer biological treatments and includes the management of the common side effects associated with the management of solid tumours in adults. It includes a succinct summary of the current management of common cancers. Cancer is an important cause of morbidity and mortality, particularly in industrialized countries. Currently in the UK, one person in two will be diagnosed with some form of cancer during their lifetime and one in four will die of the disease. Cancer incidence increases exponentially with age; with increasing life expectancy, cancer will become an even more common problem in the future. Cancers may develop in all body tissues. The chapter reviews the various ways that the cells that form cancers can be differentiated from cells in normal tissues.

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