A planar phased-array antenna has been constructed from a 15x15 square grid of z-directed monopoles with a length of 0.475 λ, element spacing of 0.29 λ, average directivity of 20.0 dBi across all scan angles, an average H-plane HPBW of 37 degrees, an average E-plane HPBW of 23 degrees, and an efficiency of 99.6%. Two current distributions are tested: uniform and binomial. The binomial current d...

abtract background: in nuclear medicine, phantoms are mainly used to evaluate the overall performance of the imaging systems and practically there is no phantom exclusively designed for the evaluation of the software performance.  in this study the hoffman brain phantom was used for quantitative evaluation of reconstruction techniques. the phantom is modified to acquire tomographic and planar i...

PURPOSE To develop a purpose-built quiet echo planar imaging capability for fetal functional and diffusion scans, for which acoustic considerations often compromise efficiency and resolution as well as angular/temporal coverage. METHODS The gradient waveforms in multiband-accelerated single-shot echo planar imaging sequences have been redesigned to minimize spectral content. This includes a s...

OBJECTIVES To compare different methods of measuring tumor growth after resection of vestibular schwannoma and to identify predictors of growth. STUDY DESIGN Retrospective case review. SETTING Tertiary referral center, inpatient surgery with ambulatory follow-up. PATIENTS All patients who underwent vestibular schwannoma resection by the senior author from September 1991 to April 2012 and ...

Patients had the 3Tesla MRI scan after 4.5 days from the index event. The structural MRI protocol, including standard MR sequences (DWI axial image, 3D T1 MP RAGE, 3D FLAIR, GRE) was applied to identify MR visible abnormalities. Axial diffusion-weighted images were acquired by using a spin-echo echo-planar imaging sequence (repetition time (TR)/echo time (TE), 2800/77 ms; field of view (FOV), 2...

We present results of a coherent x-ray diffractive imaging experiment performed on a single colloidal crystal grain. The full three-dimensional (3D) reciprocal space map measured by an azimuthal rotational scan contained several orders of Bragg reflections together with the coherent interference signal between them. Applying the iterative phase retrieval approach, the 3D structure of the crysta...

Target localization using single photon emission computed tomography (SPECT) and planar imaging is being investigated for guiding radiation therapy delivery. Previous studies on SPECT-based localization have used computer-simulated or hybrid images with simulated tumors embedded in disease-free patient images where the tumor position is known and localization can be calculated directly. In the ...

density functional theory (dft) calculations were performed to investigate the properties of planar, tubular and conical forms of silicon nanostructures. the evaluated parameters including averaged bond lengths, binding energies, gap energies and dipole moments were then evaluated for the optimized models of study. the results indicated that the bond lengths between silicon atoms are different ...

Density functional theory (DFT) calculations were performed to investigate the properties of planar, tubular and conical forms of silicon nanostructures. The evaluated parameters including averaged bond lengths, binding energies, gap energies and dipole moments were then evaluated for the optimized models of study. The results indicated that the bond lengths between silicon atoms are different ...