introduction:  the  purpose  of  this  study  is  to  define  the  optimal  parameters  for  the  tomographic  reconstruction procedure in a routine single photon emission tomography. the hoffman brain phantom  is modified to evaluate the reconstruction method. the phantom was imaged in a 3 and 2-dimensional  conformation and the results were compared.   materials  and  methods:  the  2d  phant...

OBJECTIVE To describe the prevalence of and risk factors for experiencing "phantom vibrations," the sensory hallucination sometimes experienced by people carrying pagers or cell phones when the device is not vibrating. DESIGN Cross sectional survey. SETTING Academic medical centre. PARTICIPANTS 176 medical staff who responded to questionnaire (76% of the 232 people invited). Measurements ...

We report on the low-dimensional magnetic behavior of series compounds ${\mathrm{NiNb}}_{2\ensuremath{-}x}{\mathrm{V}}_{x}{\mathrm{O}}_{6}$ ($0\ensuremath{\le}x\ensuremath{\le}2$), with a columbite-type crystal structure stabilized at high pressure and temperature. Based susceptibility, magnetization, specific-heat measurements, system is characterized as presenting quasi-one-dimensional magnet...

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...

The effect of gantry rotation on beam profiles of photon and electron beams is an important issue in quality assurance for radiotherapy. To address variations in the profiles of photon and electron beams at different gantry angles, a Dynamic Phantom scanner composed of a 20 x 12 x 6 cm3 scanning Lucite block was designed as a cross-beam-profile scanner. To our knowledge, differences between sca...

Though antiferroelectricity in PbZrO${}_{3}$ was discovered over 70 years ago, there is still no consensus on the exact physical mechanism behind its formation. In this study, authors rationalize antiferroelectric $P\phantom{\rule{0}{0ex}}b\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}m$ state of as a modulated phase, where polarization and antiphase O${}_{6}$ octahedra tilts are coupled via t...

PURPOSE The emergence of thermal modalities has promoted the use of heat-sensitive phantoms for calibration, measurement, and verification purposes. However, development of durable phantoms with high precision ability to represent the temperature distribution remains a challenge. This study aims to introduce a reusable phantom that provides an accurate assessment of the heated region in various...

We report the high-field superconducting properties of thin, disordered Re films via magnetotransport and tunneling density states measurements. Films with thicknesses in range 9 to 3 nm had normal-state sheet resistances $\ensuremath{\sim}0.2\phantom{\rule{4pt}{0ex}}\mathrm{k}\mathrm{\ensuremath{\Omega}}$ $\ensuremath{\sim}1\phantom{\rule{4pt}{0ex}}\mathrm{k}\mathrm{\ensuremath{\Omega}}$ corre...

The present study quantified surface doses on several rectangular phantom setups and on curved surface phantoms for a 6 MV photon field using the Attix parallel-plate chamber and Gafchromic EBT2 film. For the rectangular phantom setups, the surface doses on a homogenous water equivalent phantom and a water equivalent phantom with 60 mm thick lung equivalent material were measured. The measureme...