Related Experiment Videos
Evaluation of a parallel hole grid for bedside chest imaging
1Department of Radiological Sciences and Technology, Massachusetts General Hospital, Boston 02114.
Investigative Radiology
|July 1, 1994
Summary
A new parallel hole grid for bedside radiography offers greater tolerance to positioning errors than conventional grids. While providing less contrast improvement than traditional grids, it enhances lung contrast compared to no grid techniques.
Area of Science:
- Radiologic Technology
- Medical Imaging Physics
Background:
- Conventional radiographic grids require precise alignment.
- Positioning errors can degrade image quality and increase patient exposure.
- Bedside radiography presents unique challenges for grid alignment.
Purpose of the Study:
- To evaluate a novel parallel hole grid for bedside radiography.
- To assess its tolerance to positioning errors compared to conventional grids.
- To quantify its performance in contrast improvement and scatter rejection.
Main Methods:
- Phantom studies comparing a parallel hole grid with 6:1 and 12:1 conventional grids.
- Measurement of contrast improvement, scatter fractions, and exposure factors.
- Assessment of tolerance to intentional positioning errors.
Main Results:
- The parallel hole grid demonstrated significantly higher tolerance to positioning errors.
- Contrast improvement and scatter rejection were lower than with a 6:1 conventional grid.
- Lung contrast increased by 13%-20% compared to nongrid techniques.
Conclusions:
- The parallel hole grid is suitable for bedside imaging, reducing alignment concerns.
- It requires higher entrance exposure (2.7x nongrid) and offers less contrast improvement than an aligned 6:1 grid.
- Performance exceeds a 6:1 grid at angulations greater than 8 degrees.