Introduction: Attenuation correction is a useful process for improving myocardial perfusion SPECT and is dependent on activity and distribution of attenuation coefficients in the body (attenuation map). Attenuation artifacts are a common problem in myocardial perfusion SPECT. The aim of this study was to compare the effect of attenuation correction using different a...

Distributed measurement of humidity is a sought-after capability for various fields of application, especially in the civil engineering and structural health monitoring sectors. This article presents a method for distributed humidity sensing along polymethyl methacrylate (PMMA) polymer optical fibers (POFs) by analyzing wavelength-dependent Rayleigh backscattering and attenuation characteristic...

Computed tomography (CT) using metrizamide is a valuable tool in the neuroradiologic evaluation of the spinal cord, but CT must be used with care when measuring object size because size may vary with different window center (level) settings. A simple method to determine appropriate window center (level) settings during CT object measurement is described. A polystyrene core with a Teflon outer c...

BACKGROUND/AIMS Quantitative and objective technique to assess radiation-induced tissue fibrosis is important for clinicians to estimate the efficiency of radiotherapeutic schemes. It has been widely reported that ultrasonic properties are sensitive to changes of acoustic scatterers in biological tissues. Therefore, measurement of ultrasonic properties may serve as a potential assessment techni...

The radiation of an elastic wave field from a plane piston source is formulated using the representation theorem, in which the Green's function for an elastic half space is employed. On the basis of this formulation, we derive the radiated elastic wave field for both compressional and shear wave sources. We study the diffraction of elastic waves incident on a receiver that is coaxially aligned ...

background and aims. cone-beam computed tomography (cbct) is an imaging system which has many advantages over computed tomography (ct). in ct scan, hounsfield unit (hu) is proportional to the degree of x-ray attenuation by the tissue. in cbct, the degree of x-ray attenuation is shown by gray scale (voxel value). the aim of the present study was to investigate the relationship between gray scale...

Satellite beacon is a signal which does not modulated and sent to ground in constant frequency with specific designed power. Beacon signals are used by station antenna users track the satellite easily. The operators generally choose at Ku Band band since this more resistant rain attenuation. system performance describe contribute of rainfall rate This paper includes comparison attenuation takin...

The prediction of wall losses is a fundamental aspect in the planning of cellular systems. The broad variety of building materials and construction codes makes accurate attenuation prediction very difficult without the support of specific construction data or measurements. In this paper, the attenuation and equivalent electric parameters and of brick and doubly reinforced concrete walls are est...

In the measurement of acoustic attenuation that obeys a power-low alpha = beta f, the traditional through-transmission method uses only the amplitude information of the recorded pulses to determine the two parameters, beta and n. In this paper, we propose a new method that utilizes both the amplitude and phase information of the pulses to determine the two parameters. According to this method, ...

The pulse broadening and decay of coherent sound waves propagating in disordered granular media are investigated. We find that the pulse width of these compressional waves is broadened when the disorder is increased by mixing the beads made of different materials. To identify the responsible mechanism for the pulse broadening, we also perform the acoustic attenuation measurement by spectral ana...