Radiographic grids are devices designed to minimize scatter radiation while preserving the primary X-rays that contribute to image formation.

1. Radiographic Grid
Presenter: Dr. Dheeraj Kumar
MRIT, Ph.D. (Radiology and Imaging)
Assistant Professor
Medical Radiology and Imaging Technology
School of Health Sciences, CSJM University, Kanpur
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 1

2. Introduction
• Radiographic grids are devices designed to
minimize scatter radiation while preserving the
primary X-rays that contribute to image
formation.
• They consist of alternating radiopaque lead strips
and interspace material, creating a matrix that
selectively allows primary radiation to pass
through while absorbing scattered radiation.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 2

3. Working Principle
• The working principle of radiographic grids lies in
their ability to absorb scattered radiation.
• When X-rays pass through the patient, some are
scattered in various directions.
• The lead strips in the grid absorb a significant
portion of this scattered radiation. As a result, the
primary X-rays, necessary for image formation,
remain predominant.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 3

4. History
• The mid-20th century marked a turning point
with the introduction of the first radiographic
grids.
• Pioneers like Hollis Potter and Gustave Bucky
recognized the need to tackle the issue of
scatter and explored innovative solutions.
• In 1904, Bucky's invention of the grid, known
as the "Bucky Grid," was a pivotal step toward
achieving clearer images.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 4

5. Types of Grids
• Parallel Grids: These have lead strips running
parallel to each other and are well-suited for
examinations with minimal divergence of X-
ray beams.
• Focused Grids: In these grids, lead strips are
angled to match the divergence of X-rays,
reducing the risk of grid cut-off and allowing
for greater latitude in patient positioning.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 5

6. Moving grids
• Moving grids are innovative devices
designed to counteract the challenges
associated with stationary grids.
• They incorporate a mechanism that
introduces controlled motion to the grid
during the X-ray exposure.
• This motion helps minimize the impact
of grid lines, grid cut-off, and the Moiré
effect on the final radiographic image.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 6

7. Scatter Radiation and Its Effects
• Scatter Radiation Defined: Scatter radiation refers to secondary X-rays
that result from the interaction of primary X-rays with patient tissues.
It contributes to decreased image quality.
• Impact on Image Quality: Scatter radiation reduces image contrast,
blurs fine details, and affects overall diagnostic accuracy, making its
control vital.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 7

8. Components of Radiographic Grids
• Radiopaque Strips: Radiopaque lead strips within
the grid absorb scattered radiation, preventing it
from reaching the image receptor.
• Interspace Material: Interspace material, often
made of aluminum or plastic, allows primary X-
rays to pass through, contributing to the formation
of the radiographic image.
• Grid Ratio: Grid ratio is the ratio of the height of
the lead strip to the width of the interspace
material. It determines scatter absorption
efficiency and image quality.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 8

9. Grid Ratio and Image Quality
• Grid Ratio Explained: Grid ratio directly impacts
image quality. A higher grid ratio increases scatter
absorption, enhancing image contrast but also
requiring higher exposure factors.
• Choosing the Right Ratio: Selecting the
appropriate grid ratio depends on the imaging
scenario. Higher ratios are favoured for
specialized imaging while lower ratios balance
dose and image quality.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 9

10. Grid Frequency and Detail
• Understanding Grid Frequency: Grid frequency
refers to the number of lead strips per unit
length (usually per inch or centimeter). Higher
grid frequency reduces visibility of grid lines on
the image.
• Influence on Image Detail: Higher grid
frequency results in improved image detail and
clarity, making it ideal for capturing fine
anatomical structures.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 10

11. Grid Alignment and Focusing Distance
• Importance of Proper Alignment: Accurate
alignment of the grid and central X-ray
beam is essential to prevent grid cut-off
and ensure consistent image quality across
the entire field.
• Impact of Focusing Distance: Maintaining
the recommended focusing distance
between the grid and the patient helps
optimize image quality by minimizing
distortion and artifacts.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 11

12. Grid Cut-off and Errors
• Grid Cut-off Explained: Grid cut-off occurs when improper
positioning or incorrect technique factors lead to a reduction in
primary radiation reaching the image receptor.
• Common Errors: Off-center grids result from misalignment of the X-
ray tube and grid, while upside-down grids lead to grid cutoff due to
reversed lead strip orientation.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 12

13. Advancements in Grid Technology
• Moving Grids: Moving grids introduce dynamic motion during
exposure to minimize the appearance of grid lines on the image,
enhancing image quality.
• Stationary Grids with Software Correction: Stationary grids, coupled
with software-based corrections, compensate for grid-related artifacts,
resulting in cleaner images.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 13

14. Digital Radiography and Grids
• Grid Considerations in Digital Imaging: Digital
imaging systems require adjustments due to
increased grid absorption, necessitating
modifications in technique factors.
• Importance of Grids in Digital Imaging:
Despite advancements in digital technology,
grids remain essential for improving image
quality and diagnostic accuracy.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 14

15. Practical Application and Care
• Proper Positioning: Accurate grid positioning ensures that the central
X-ray beam is aligned, minimizing artifacts and maintaining image
quality.
• Collimation and Field Coverage: Proper collimation not only reduces
patient exposure to radiation but also ensures the image is well-
centered and high in quality.
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 15

16. References
• Bushong, S. C. (2018). Radiologic Science for Technologists: Physics, Biology, and Protection. Mosby.
• Fauber, T. L. (2019). Radiographic Imaging and Exposure. Elsevier Health Sciences.
• Carlton, R. R., & Adler, A. M. (2016). Principles of Radiographic Imaging: An Art and A Science. Cengage
Learning.
• Clark, K. R., Bushong, S. C., & Slovis, T. L. (2019). Essentials of Radiographic Physics and Imaging.
Elsevier Health Sciences.
•
04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 16

17. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 17