نتایج جستجو برای: neck phantom
تعداد نتایج: 103711 فیلتر نتایج به سال:
The present study evaluates the performance of a newly released photon-beam dose calculation algorithm that is incorporated into an established treatment planning system (TPS). We compared the analytical anisotropic algorithm (AAA) factory-commissioned with "golden beam data" for Varian linear accelerators with measurements performed at two institutions using 6-MV and 15-MV beams. The TG-53 eva...
A mini-ridge filter is often used to widen the Bragg peak in the longitudinal direction at low energies but not high energies. To facilitate the clinical use of a mini-ridge filter, we performed a planning study for the feasibility of a mini-ridge filter as an integral part of the synchrotron nozzle (IMRF). Dose models with and without IMRF were commissioned in a commercial Treatment planning s...
abstract background: while the benefits of computed tomography (ct) are well known in accurate diagnosis, those benefits are not risk free. ct is a device with higher patient dose in comparison with other conventional radiological procedures. is the reduction of exposures by requiring optimization of ct procedures [a principle concern in radiological protection]? in this study, the radiation ...
Two cosmological models with non-phantom matter having the same expansion of the universe as phantom cosmologies are constructed. The first model is characterized by the evolving gravitational “constant” G and a dark energy component with a non-conserved energy-momentum tensor. The second model includes two interacting components, the dark energy component and the matter component. Closed form ...
An analysis with a transferred hyperfine field has been performed on the spectra of $^{115}\mathrm{In}$ nuclear quadrupole resonance experiments heavy fermion superconductor ${\mathrm{Ce}}_{3}{\mathrm{PtIn}}_{11}$ exhibiting co-occurrence two successive antiferromagnetic orderings (${T}_{\mathrm{N}1}$ = 2.2 K and ${T}_{\mathrm{N}2}$ 2.0 K) followed by superconducting transition (${T}_{\mathrm{c...
OBJECTIVES To determine the effective dose and CT dose index (CTDI) for a range of imaging protocols using the Sirona GALILEOS(®) Comfort CBCT scanner (Sirona Dental Systems GmbH, Bensheim, Germany). METHODS Calibrated optically stimulated luminescence dosemeters were placed at 26 sites in the head and neck of a modified RANDO(®) phantom (The Phantom Laboratory, Greenwich, NY). Effective dose...
Automatic tube current modulation (ATCM) systems are available for all CT manufacturers and are used for the majority of patients. Understanding how the systems work and their influence on patient dose and image quality is important for CT users, in order to gain the most effective use of the systems. In the present study, a new phantom was used for evaluating dose distribution and image qualit...
OBJECTIVES To demonstrate the feasibility of GafChromic(®) XR-QA2 (ISP Corp., Wayne, NJ) as a dosemeter when performing measurements of the effective dose from three cone beam CT (CBCT) units and to compare the doses from examinations of three common dental clinical situations. A second aim was to compare the radiation doses for three digital panoramic units with the doses for the CBCT units. ...
Defect engineering plays an important role in tailoring the electronic transport properties of van der Waals materials. Methods reported so far mainly rely on $e\phantom{\rule{0}{0ex}}x\phantom{\rule{0.333em}{0ex}}s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ defect type and concentration, hindering realization new types device functionalities associated with engine...
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