Grids

Grids

Write short note on grid.
Answer.

Grid

• These are devices which reduces the amount of scattered radiation reaching the film and still allowing the primary beam to reach the film.
• Thus, grid prevent scattered radiation which reduces fog and increases contrast.

“Understanding the role of grids in improving X-ray image quality: Q&A explained”

Grid Composition

A grid is composed of alternative strips of radiopaque and radiolucent material

• Radiopaque material is lead.
• Radiolucent material is plastic.

Potter-Bucky diaphragm

• The radiopaque material absorbs the scattered radiations while the radiolucent material allows passage of primary radiation.

“Early warning signs of issues caused by improper grid use: Common questions”

“Importance of studying grids for better diagnostic accuracy: Questions explained”

Types of Grid

Following are the grids used, i.e.

• Stationary grids and moving grids
• Focused grids and non-focused grids

Radiology grid Stationary Grids

Stationary grids do not move.

• Linear grid
• • In this, strips of lead are used which are placed strictly parallel to each other.
  • Here the primary radiations travel radially from X-ray tube focal spot to the film will encounter the grid obliquely. So grid lines appear wider.
  • While using the linear grid, cut-off of the beam may occur as some primary radiation can be absorbed by lead which is situated in peripheral region.
  • For all practical applications, central beam in the plane is parallel with grid lines.

“Common challenges in using grids effectively in radiography: FAQs provided”

Stationary and moving grids in X-ray

• Focused grid
  • Here strips of lead are angled progressively from center to the edge so the inter spaces are directed at the focal spot.
  • Focused grid helps in prevention of primary cut-off.
  • Focused grid minimizes the disadvantages of linear grid.
• Pseudo-focused grid
  • Here the height of strips is reduced progressively from centre which leads to reduction in grid ratio from center to edge.
• Crossed grid
  • Linear grids are placed mutually at the right angles so even the small amount of radiation is blocked.

“Asymptomatic vs symptomatic effects of ignoring proper grid protocols: Q&A”

X-ray grid

Moving Grids

• These grids move sideways across the film during the exposure.
• These grids reduce the white lead lines in the radiographic image.

“Steps to explain different types of grids: Focused vs parallel grids: Q&A guide”

“Role of high-ratio grids in minimizing scatter radiation: Questions answered”

Grid Advantages 

Grids remove the scattered radiation efficiently which leads to decrease in film fog and increases radiographic contrast.

Focused grid radiology

Grid Disadvantages

• The radiopaque material (lead) may absorb some primary radiation and produces overall pattern of thin parallel white lines on the film called grid lines.
• The exposure time must be increased.