DIFFERENT TYPES OF GRIDS PORTABLE

Ī stand-alone microgrid has its own sources of electricity, supplemented with an energy storage system. This kind of grids are called ' islandable microgrids'. In this way, they improve the security of supply within the microgrid cell, and can supply emergency power, changing between island and connected modes. Ī grid-connected microgrid normally operates connected to and synchronous with the traditional wide area synchronous grid (macrogrid), but is able to disconnect from the interconnected grid and to function autonomously in 'island mode' as technical or economic conditions dictate. A ' Stand-alone microgrid' or ' isolated microgrid' only operates off-the-grid and cannot be connected to a wider electric power system. It is able to operate in grid-connected and in island mode. slice-overlap artifact a.k.a.A microgrid is a local electrical grid with defined electrical boundaries, acting as a single and controllable entity.propylene glycol peak: resonates at 1.13 ppm.N-acetylaspartate (NAA) peak: resonates at 2.0 ppm.glutamine-glutamate peak: resonates at 2.2-2.4 ppm.gamma-aminobutyric acid (GABA) peak: resonates at 2.2-2.4 ppm.2-hydroxyglutarate peak: resonates at 2.25 ppm.arterial spin labeling (ASL) MR perfusion.dynamic contrast enhanced (DCE) MR perfusion.dynamic susceptibility contrast (DSC) MR perfusion.metal artifact reduction sequence (MARS).turbo inversion recovery magnitude (TIRM).fluid attenuation inversion recovery (FLAIR).diffusion tensor imaging and fiber tractography.MRI pulse sequences ( basics | abbreviations | parameters).iodinated contrast-induced thyrotoxicosis.iodinated contrast media adverse reactions.clinical applications of dual-energy CT.as low as reasonably achievable (ALARA).However, this leads to increased x-ray tube loading and radiation exposure to the patient. Image contrast can be improved by increasing the grid ratio by increasing the height of the lead strips or reducing the interspace. The contrast improvement factor is the ratio between the contrast with a grid and without a grid. It indicates the increase in patient dose due to the use of a grid. The Bucky factor is the ratio of radiation on the grid to the transmitted radiation. Generally used where the anatomy is >10 cm:īarium studies (including lateral cervical)īreast ( mammography): uses 4:1 grid ratio Grids are commonly used in radiography, with grid ratios available in even numbers, such as 4:1, 6:1, 8:1, 10:1 or 12:1.

DIFFERENT TYPES OF GRIDS PORTABLE

Moving grids (also known as Potter-Bucky or reciprocating grids): eliminates the fine grid lines that may appear on the image when focused or parallel grids are used cannot be used for portable films Parallel grid: used for short fields or long distances Virtual grid: no actual grid is used latest innovation for scatter reduction by digitally reconstructing a radiographįocused grids (most grids): strips are slightly angled so that they focus in space so must be used at specified focal distances The strip line density (number of strips per cm) is 1/(D+d), where d is the thickness of the strip. A grid ratio of 8:1 is generally used for 70-90 kVp technique and 12:1 is used for >90 kVp technique. The working ability of a grid is described by the grid ratio, which is the ratio of the height of the lead strips (h) to the distance between two strips, i.e. the interspace (D).

As scattered radiation is increased in 'thicker' patients and at larger field sizes, grids are useful in such scenarios to improve image contrast.

The strips can be oriented either linear or crossed in their longitudinal axis. They are made of parallel strips of high attenuating material such as lead with an interspace filled with low attenuating material such as carbon fiber or organic spacer. Grids are placed between the patient and the x-ray film to reduce the scattered radiation reaching the detector (produced mainly by the Compton effect) and thus improve image contrast.

Different types of grids