MATSIM: A voxel model for the astronaut dosimetric phantom MATROSHKA

2011 ◽  
Author(s):  
P. Beck ◽  
S. Rollet ◽  
M. Hajek ◽  
A. Zechner ◽  
M. Latocha ◽  
...  
Keyword(s):  
Voxel Model

Line-Based Structure for Voxel Model

2021 ◽  
Author(s):  
Fan Jiangxin ◽  
Jing Shikai ◽  
Che Lei ◽  
Liu Tianren ◽  
Shi Zefang ◽  
...  
Keyword(s):  
Voxel Model

scholarly journals Detecting phase singularities and rotor center trajectories based on the Hilbert transform of intraatrial electrograms in an atrial voxel model

2015 ◽  
Vol 1 (1) ◽  
pp. 38-41 ◽  
Author(s):  
Laura Anna Unger ◽  
Markus Rottmann ◽  
Gunnar Seemann ◽  
Olaf Dössel
Keyword(s):  
Atrial Fibrillation ◽  
Blood Volume ◽  
Hilbert Transform ◽  
Rf Ablation ◽  
Voxel Model ◽  
Rotor Center ◽  
Phase Singularities ◽  
Endocardial Surface ◽  
The Hilbert Transform ◽  
Unipolar Electrograms

AbstractThis work aimed at the detection of rotor centers within the atrial cavity during atrial fibrillation on the basis of phase singularities. A voxel based method was established which employs the Hilbert transform and the phase of unipolar electrograms. The method provides a 3D overview of phase singularities at the endocardial surface and within the blood volume. Mapping those phase singularities from the inside of the atria at the endocardium yielded rotor center trajectories. We discuss the results for an unstable and a more stable rotor. The side length of the areas covered by the trajectories varied from 1.5 mm to 10 mm. These results are important for cardiologists who target rotors with RF ablation in order to cure atrial fibrillation.

Voxel model in BNCT treatment planning: performance analysis and improvements

2005 ◽  
Vol 50 (3) ◽  
pp. 441-458 ◽  
Author(s):  
Sara J González ◽  
Daniel G Carando ◽  
Gustavo A Santa Cruz ◽  
Robert G Zamenhof
Keyword(s):  
Performance Analysis ◽  
Treatment Planning ◽  
Voxel Model

Proton Dose Conversion Coefficients Based on Chinese Reference Adult Woman Voxel Phantom

2013 ◽  
Author(s):  
Fangfang Liu ◽  
Mingqi Shen ◽  
Taosheng Li ◽  
Chunyu Liu
Keyword(s):  
Effective Dose ◽  
Reference Data ◽  
Absorbed Dose ◽  
The Body ◽  
Adult Woman ◽  
Voxel Model ◽  
Conversion Coefficients ◽  
Computational Phantoms ◽  
Posterior Anterior ◽  
Anterior Posterior

In order to calculate the dose conversion coefficients for proton, the voxel model of Chinese Reference Adult Woman (CRAW) was established by the Monte Carlo transport code FLUKA according to the Chinese reference data and the Asian reference data. Compared with the reference data, the deviations of the mass for organs or tissues of CRAW is less than ±5%. Calculations have been performed for 14 incident monoenergetic protons energies from 0.02GeV to 10TeV at the irradiation incident of anterior-posterior (AP) and posterior-anterior (PA). The results of fluence-to-effective dose conversion coefficients are compared with data from the different models such as an anthropomorphic mathematical model, ICRP reference adult voxel model, the voxel-based visible Chinese human (VCH). Anatomical differences among various computational phantoms and the spatial geometric positions of the organs or tissues lead to the discrepancies of the effective dose conversion coefficients in the ranging from a negligible level to 107% at proton energies below 0.2GeV. The deviations of the coefficients, above 0.2GeV, are mostly within 10%. The results of fluence-to-organ absorbed dose conversion coefficients are compared with the data of VCH. The deviations of the coefficients, below and above 0.2GeV, are within 150% and 20%, respectively. The primary factors of the deviations for the coefficients should be due to the differences of the organ mass and the size of the body shape.

Voxel model surface offsetting for computer-aided manufacturing using virtualized high-performance computing

2017 ◽  
Vol 43 ◽  
pp. 296-304 ◽  
Author(s):  
Roby Lynn ◽  
Didier Contis ◽  
Mohammad Hossain ◽  
Nuodi Huang ◽  
Tommy Tucker ◽  
...  
Keyword(s):  
High Performance Computing ◽  
High Performance ◽  
Model Surface ◽  
Computer Aided Manufacturing ◽  
Computer Aided ◽  
Voxel Model ◽  
Performance Computing

A Voxel Model-Based Process-Planning Method for Five-Axis Machining of Complicated Parts

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Yamin Li ◽  
Kai Tang ◽  
Long Zeng
Keyword(s):  
Process Planning ◽  
Planning Method ◽  
Dynamic Problems ◽  
Tool Paths ◽  
New Process ◽  
Part Surface ◽  
Voxel Model ◽  
Voxel Representation ◽  
Complex Features ◽  
Five Axis

Abstract This paper presents a new process planning method for five-axis machining, which is particularly suitable for parts with complex features or weak structures. First, we represent the in-process workpiece as a voxel model. Facilitated by the voxel representation, a scalar field called subtraction field is then established between the blank surface and the part surface, whose value at any voxel identifies its removal sequence. This subtraction field helps identify a sequence of intermediate machining layers, which are always accessible to the tool and are free of self-intersection and the layer redundancy problem as suffered, respectively, by the traditional offset layering method and the morphing method. Iso-planar collision-free five-axis tool paths are then determined on the interface surfaces of these machining layers. In addition, to mitigate the deformation of the in-process workpiece and avoid potential dynamic problems such as chattering, we also propose a new machining strategy of alternating between the roughing and finishing operations, which is able to achieve a much higher stiffness of the in-process workpiece. Ample experiments in both computer simulation and physical cutting are performed, and the experimental results convincingly confirm the advantages of our method.

scholarly journals Dosimetric evaluation in radiation synovectomy

2005 ◽  
Vol 48 (spe2) ◽  
pp. 153-158 ◽  
Author(s):  
Carla Flávia de Lima ◽  
Tarcisio Passos Ribeiro de Campo
Keyword(s):  
Rheumatoid Arthritis ◽  
Articular Cartilage ◽  
Synovial Membrane ◽  
Half Life ◽  
Three Dimensional ◽  
Low Energy ◽  
Radioactive Material ◽  
Radiation Synovectomy ◽  
Voxel Model ◽  
The Common

Rheumatoid arthritis can manifest itself through synovitis, of which the knee is the common locale. The treatment using an intra-articular radioisotope injection has been applied in various countries. In this work, the dose of radioactive material absorbed in the joint is evaluated, taking into consideration the dose received in the articular cartilage and adjacencies using a three-dimensional voxel model representing the knee. The radioisotopes studied were Samarium-153 and Dysprosium-165. The results show that the synovial membrane receives 85 to 98% of the normalized dose taken from all voxels representative of the synovium. The following features of 153Sm and of 165Dy - its short physical half-life, the gamma emissions with low energy which allow monitoring the injection trough scintigraphy images, the possibility of binding themselves to macroaggregates that are retained in the joint, the high percentage of the effective dose spread in the synovial membrane - make these suitable radioisotopes for radiation synovectomy.

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