Grids
Updates to Article Attributes
Grids are placed between the patient and the X-ray film to reduce the scattered radiation (produced mainly by compton effect) and thus improve image contrast.
They are made of parallel strips of lead with an interspace having an aluminum or organic spacer. The strips can be oriented either linear or crossed in their longitudinal axis. As the scatter radiation is increased in "thicker" patients and at larger field sizes, grids are useful in such scenarios to improve image contrast.
The working ability of a grid is described by thegrid ratio, which is the ratio of height of the lead strips to the distance between two strips (the interspace). The higher the grid ratio, the better the image contrast but at a cost of increased patient dose. Grid ratio of 8:1 is generally used for for 70-90 kVp technique and 12 and 12:1 is used for for >90 kVp technique.
Types
- focussed grids (most grids): strips are slightly angled so that they focus in space
- parallel grid: used for short fields or long distances
- moving grids (also known as Potter-Bucky grids): eliminates the fine grid lines that may appear on the image when focussed or parallel grids are used
Uses
Grids are commonly used in radiography, with grid ratio available in even numbers, such as 8:1, 10:1 or 12:1 and 4:1 and 6:1
Generally used where the anatomy is greater than 10cm
- abdomen
- skull
- spine (except lateral cervical)
- contrast studies
- IVU
- RGU
- MCU
- barium studies
(except(including lateral cervical)
- breast (mammography): uses 4:1 grid ratio
Please note:
The Internet allows you to access information from anywhere, and at any time. However, the knowledge you retrieve may be a confusing collection of information in a wide variety of formats. Online information, along with your print resources, must ALWAYS be evaluated for relevance, currency, reliability, accuracy and coverage.
-<p><strong>Grids </strong>are placed between the patient and the X-ray film to reduce the scattered radiation (produced mainly by <a href="/articles/compton-effect">compton effect</a>) and thus improve image contrast.</p><p>They are made of parallel strips of lead with an interspace having an aluminum or organic spacer. The strips can be oriented either linear or crossed in their longitudinal axis. As the scatter radiation is increased in "thicker" patients and at larger field sizes, grids are useful in such scenarios to improve image contrast.</p><p>The working ability of a grid is described by the <strong>grid ratio</strong>, which is the ratio of height of the lead strips to the distance between two strips (the interspace). The higher the grid ratio, the better the image contrast but at a cost of increased patient dose. Grid ratio of 8:1 is generally used for 70-90 kVp technique and 12:1 is used for >90 kVp technique.</p><h5>Types</h5><ul>-<li>focussed grids (most grids): strips are slightly angled so that they focus in space</li>-<li>parallel grid: used for short fields or long distances</li>-<li>moving grids (also known as Potter-Bucky grids): eliminates the fine grid lines that may appear on the image when focussed or parallel grids are used</li>-</ul><h5>Uses</h5><p>Grids are commonly used in radiography with grid ratio 8:1 or 12:1 and 4:1</p><ul>-<li>abdomen</li>-<li>skull</li>-<li>spine (except lateral cervical)</li>-<li>contrast studies<ul>-<li>IVU</li>-<li>RGU</li>-<li>MCU</li>-<li>barium studies (except lateral cervical)</li>-</ul>-</li>-<li>breast (<a href="/articles/mammography">mammography</a>): uses 4:1 grid ratio</li>-</ul>- +<p><strong>Grids </strong>are placed between the patient and the X-ray film to reduce the scattered radiation (produced mainly by <a href="/articles/compton-effect">compton effect</a>) and thus improve image contrast.</p><p>They are made of parallel strips of lead with an interspace having an aluminum or organic spacer. The strips can be oriented either linear or crossed in their longitudinal axis. As the scatter radiation is increased in "thicker" patients and at larger field sizes, grids are useful in such scenarios to improve image contrast.</p><p>The working ability of a grid is described by the <strong>grid ratio</strong>, which is the ratio of height of the lead strips to the distance between two strips (the interspace). The higher the grid ratio, the better the image contrast but at a cost of increased patient dose. Grid ratio of 8:1 is generally used for 70-90 kVp technique and 12:1 is used for >90 kVp technique.</p><h5>Types</h5><ul>
- +<li>focussed grids (most grids): strips are slightly angled so that they focus in space</li>
- +<li>parallel grid: used for short fields or long distances</li>
- +<li>moving grids (also known as Potter-Bucky grids): eliminates the fine grid lines that may appear on the image when focussed or parallel grids are used</li>
- +</ul><h5>Uses</h5><p>Grids are commonly used in radiography, with grid ratio available in even numbers, such as 8:1, 10:1 or 12:1 and 4:1 and 6:1 </p><p>Generally used where the anatomy is greater than 10cm</p><ul>
- +<li>abdomen</li>
- +<li>skull</li>
- +<li>spine (except lateral cervical)</li>
- +<li>contrast studies<ul>
- +<li>IVU</li>
- +<li>RGU</li>
- +<li>MCU</li>
- +<li>barium studies (including lateral cervical)</li>
- +</ul>
- +</li>
- +<li>breast (<a href="/articles/mammography">mammography</a>): uses 4:1 grid ratio</li>
- +</ul><p>Please note:</p><p>The Internet allows you to access information from anywhere, and at any time. However, the knowledge you retrieve may be a confusing collection of information in a wide variety of formats. Online information, along with your print resources, must ALWAYS be evaluated for relevance, currency, reliability, accuracy and coverage.</p><p> </p>
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