Online Geometric Calibration of a Hybrid CT System for Ultrahigh-Resolution Imaging

Area of Science:

• Medical Imaging
• Radiology
• Biomedical Engineering

Background:

• Standard computed tomography (CT) provides valuable diagnostic information but has limitations in resolution.
• Hybrid imaging systems offer potential for enhanced image quality and detail.
• Photon-counting detectors represent an advancement in X-ray imaging technology.

Purpose of the Study:

• To develop and validate a method for accurate geometric registration of a photon-counting detector insert with a standard CT scanner.
• To enable the creation of ultrahigh-resolution images in specific regions of interest within chest scans.
• To improve image quality by reducing artifacts in hybrid CT imaging.

Main Methods:

• A hybrid imaging system integrating a standard CT scanner with a low-profile photon-counting detector insert was utilized.
• Fiducial markers and an iterative registration algorithm were employed to determine the precise relative geometry between the detector insert and the CT scanner for each scan.
• Complementary image datasets from both systems were combined after geometric alignment.

Main Results:

• The developed method successfully determined the relative geometry of the detector insert for accurate image reconstruction.
• Ultrahigh-resolution images were achieved in a limited volume of patient chest scans.
• Summing the complementary image sets resulted in detailed images with reduced artifacts.

Conclusions:

• A robust method for geometric registration enables the effective use of hybrid CT imaging systems with photon-counting detector inserts.
• This approach significantly enhances image resolution and reduces artifacts, offering improved diagnostic capabilities for specific thoracic imaging applications.
• Hybrid imaging holds promise for advancing diagnostic accuracy in medical imaging.