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Voltage standing wave ratio (VSWR) (pronounced "vizwar" [1] [2]) is the ratio of maximum to minimum voltage on a transmission line . For example, a VSWR of 1.2 means a peak voltage 1.2 times the minimum voltage along that line, if the line is at least one half wavelength long.
A set of many such projections under different angles organized in 2D is called a sinogram (see Fig. 3). In X-ray CT, the line integral represents the total attenuation of the beam of X-rays as it travels in a straight line through the object. As mentioned above, the resulting image is a 2D (or 3D) model of the attenuation coefficient.
The yellow lines describe how photons were scattered before the epoch of recombination and were free-streaming after. In astronomy, a free streaming particle is one that propagates through a medium without scattering. The particle is often a photon, but it can also refer to neutrinos, cosmic rays, and hypothetical dark matter particles.
The beam of X-ray is attenuated when photons are absorbed when the x-ray beam passes through the tissue. Interaction with matter varies between high energy photons and low energy photons. Photons travelling at higher energy are more capable of travelling through a tissue specimen as they have less chances of interacting with matter.
In the same way that a plain X-ray is a 2-dimensional (2-D) view of a 3-dimensional structure, the image obtained by a gamma camera is a 2-D view of 3-D distribution of a radionuclide. SPECT imaging is performed by using a gamma camera to acquire multiple 2-D images (also called projections ), from multiple angles.
From the point where the ray is parallel to ground, relative to the chosen coordinates, the ray goes down but relative to ground level, the ray goes up. Often engineers are interested in finding the limits of a system. In this case, a simple idea is to try some low elevation angle and let the ray reach the desired altitude.
The X-ray standing wave (XSW) technique can be used to study the structure of surfaces and interfaces with high spatial resolution and chemical selectivity. Pioneered by B.W. Batterman in the 1960s, [1] the availability of synchrotron light has stimulated the application of this interferometric technique to a wide range of problems in surface science.
X-ray motion analysis is a technique used to track the movement of objects using X-rays. This is done by placing the subject to be imaged in the center of the X-ray beam and recording the motion using an image intensifier and a high-speed camera , allowing for high quality videos sampled many times per second.