3D-printed large-area focused grid for scatter reduction in cone-beam CT.
Santiago Fabian Cobos1, Christopher James Norley2, Hristo Nikolaev Nikolov2
1Department of Medical Biophysics, Western University, London, Ontario, Canada.
Medical Physics
|October 10, 2022
Summary
New 2D antiscatter grids (2D-ASGs) manufactured with metal additive manufacturing improve cone-beam computed tomography (CBCT) image quality by reducing scatter radiation. This technology enhances contrast-to-noise ratio and reduces artifacts without increasing patient dose.
Area of Science:
- Medical Imaging
- Radiological Physics
Background:
- Cone-beam computed tomography (CBCT) systems offer efficient volumetric data acquisition.
- Scattered radiation in CBCT degrades image quality, causing noise, artifacts, and inaccurate CT numbers.
Purpose of the Study:
- To implement a large-area, 2D antiscatter grid (2D-ASG) for flat-panel CBCT using advanced additive manufacturing.
- To evaluate the effectiveness of the 2D-ASG in reducing scatter intensity and improving image quality, including artifact removal.
Main Methods:
- A 2D-ASG was manufactured using laser powder-bed fusion (LPBF) from a chrome-cobalt alloy.
- The 2D-ASG was coupled to a flat-panel detector, and phantom images were acquired.
- Grid-line artifacts were removed using image processing, and reconstructions were compared with and without the 2D-ASG.
Main Results:
- Successful design and manufacture of a large-area 2D-ASG using LPBF.
- Achieved a 14.5% overall increase in contrast-to-noise ratio (CNR), up to 48.8% for low-contrast inserts.
- Reduced cupping artifacts by 65% without compromising spatial resolution or geometric accuracy.
Conclusions:
- LPBF enables the production of efficient 2D-focused ASGs for clinical flat-panel detectors.
- 2D-ASGs reduce scatter artifacts, improve CT number accuracy, and enhance CNR in CBCT without increasing patient dose.
- Potential for superior soft-tissue visualization and quantitative imaging in clinical applications.
