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Showing 1 to 20 of 56 for “"collimator"”.
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Direct optimization of 3D dose distributions using collimator rotation
… optimization (DAO) platform where the multileaf collimator (MLC) is rotated between each aperture. The approach is referred to as rotating aperture optimization (RAO). A series of tests is performed to evaluate how a final optimized plan depends on MLC parameters. Imposing constraints on the leaf …
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Collimator width Optimization in X-ray Luminescent Computed Tomography
X-ray Luminescent Computed Tomography (XLCT) is a new imaging modality which is under extensive trials at present. The modality works by selective excitation of X-ray sensitive nanophosphors and detecting the optical signal thus generated. This system can be used towards recreating high quality …
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Effect of Coil Layout on the Performance of the Proton Divertor Collimator Device
Made available in DSpace on 2017-07-06T18:55:38Z (GMT). No. of bitstreams: 3 Nieto-Perez_Martin_De_Jesus_MS.pdf: 37147999 bytes, checksum: bbfc2369a7fa2a773876b62e67116abd (MD5) Nieto-Perez_Martin_De_Jesus_MS_ABS.pdf: 449263 bytes, checksum: dd277725702ca739ac2af2da2e808776 (MD5) license.txt: 4813 …
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The Design and Characterization of a Multiple Pinhole Collimator and Its Applications in Biopharmaceutics
A 4-pinhole collimator was designed to image small objects and its characteristics were studied. The field of view formed by this collimator was a conically-tipped pyramid with a minimum object distance of 3 cm. The line-spread function at 8 cm from the collimator had a full-width-half-maximum of …
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Tool design for the production of a collimator on a 3-axes vertical milling centre
… running at normal capacity consumes about one collimator in every three to four weeks. The cost of replacement of each collimator is approximately US$3800 from Mitutoyo and Fowyer in America. Chambishi Metals Pic notes that it is spending thousands of dollars in importing the component and is …
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Tool design for the production of a collimator on a 3-axes vertical milling centre
… running at normal capacity consumes about one collimator in every three to four weeks. The cost of replacement of each collimator is approximately US$3800 from Mitutoyo and Fowyer in America. Chambishi Metals Pic notes that it is spending thousands of dollars in importing the component and is …
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Assessment of Collimator Jaw Optimization In Reducing Normal Tissue Irradiation With Intensity Modulated Radiation Therapy
… Varian 2100 platform by tracking the multileaf collimator (MLC) apertures with the accelerator jaws.</p> <p><strong>Methods: </strong>Clinical radiation treatment plans for 10 thoracic, 3 pediatric and 3 head and neck patients were converted to plans with the jaws tracking each segment’s MLC …
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Super-collimation in a rod-based photonic crystal
… rod-based two-dimensional photonic crystal super-collimator. The dispersion contours for the photonic crystal are simulated as part of the design process. Two different fabrication process methods are developed and applied. The super-collimator s fabricated, and the fabrication methods are …
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Use of silicon surface-barrier detectors for neutron detection
… there was some effect on energy spread by the collimator. A collimator with essentially an infinite number of baffles was used, since it consisted of a hole drilled through the collimator material. If the number of baffles were decreased, the possibility of protons being scattered from the …
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Diagnostics for ionized physical vapor deposition chambers
… microbalance (QCM), with a high aspect ratio collimator in place of the normal electron repeller grid for angular measurement distribution measurements. The collimator is made of copper elements with 500μm nominal openings which provides 1 degree angular resolution. This combined QCM and GEA …
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Scattering and Absorption of Photons in Emission Computed Tomography
… of the photon-transport process and the collimator-detector system are used in this study so that these scattering effects can be examined independently from other imaging factors. As a result of this investigation, two techniques have been developed for improving image quality in …
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Problems in point charge electrodynamics
… there exist geometric discontinuities such as collimators and cavities. When a relativistic bunch of particles passes such a discontinuity the field generated by a leading charge can interact with the wall and consequently affect the motion of trailing charges. The fields acting on the trailing …
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MONTE CARLO MODELING OF THE GAMMA KNIFE PERFEXION<sup>TM</sup>
… healthy tissue a few millimeters away. Tungsten collimators are organized into eight sectors of 24 sources each, and can independently choose one of three collimation sizes for each sector. The largest collimator size is designed to produce a sphere of dose 16 mm in diameter at the focus. The …
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Characterisation of radiation fields with combined fast-neutron and gamma-ray imaging
… Monte Carlo optimisation and characterisation of collimator and detector geometry, followed by the subsequent design and procurement, assembly and modification to produce several probe configurations. The full system was then realised through control system design, electronic interfacing between …
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Optical system for high-speed Atomic Force Microscope
… among which the lever method and the fiber collimator method were selected. Experiments were performed to characterize the performance of the integrated AFM and to show that the cantilever tracking while the scanner is in operation was accomplished. A triangular grating was imaged with the …
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A Novel Methodology for Iterative Image Reconstruction in SPECT Using Deterministic Particle Transport
… formulation has been improved through a modified collimator representation and full parallelization. The DRS methodology has been implemented in the TITAN code to create TITAN with Image Reconstruction (TITAN-IR). The TITAN-IR code has been used to successfully reconstruct the source distribution …
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Linear-cavity tunable fibre lasers employing an Opto-VLSI processor and a MEMS-based device
… and the MEMS-based device along with an optical collimator, a Bragg grating plate and an optical lens, enable the realisation of an optical filter for continuous tuning of wavelengths over the amplified spontaneous emission (ASE) range of the EDF. We also propose the use of a section of un-pumped …
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