Geometric Parameters Estimation and Calibration in Cone-Beam Micro-CT.

Area of Science:

• Medical Imaging
• Physics
• Engineering

Background:

• Computed Tomography (CT) image quality is highly dependent on accurate scanner geometry.
• Misalignments in CT scanner geometry can lead to artifacts and reduced image fidelity.
• Precise calibration of geometric parameters is crucial before image acquisition.

Purpose of the Study:

• To develop and validate a method for estimating cone-beam CT (CBCT) geometric parameters using a novel phantom.
• To assess the effectiveness of the proposed method in reducing artifacts and improving image quality.
• To provide an easy-to-implement solution for CT scanner calibration.

Main Methods:

• Utilized a Two-Piece-Ball (TPB) phantom for geometric parameter estimation.
• Acquired multiple projections of the TPB phantom at a single position to avoid rotation errors.
• Developed and applied a corresponding algorithm for parameter calculation.
• Evaluated the method using both simulated and experimental data, including Micro-CT.

Main Results:

• The proposed TPB phantom method accurately estimates CT geometric parameters.
• The method is valid, easy to implement, and requires only single-position projections.
• Experimental results on a Micro-CT system showed significant reduction in artifacts.
• Image quality was demonstrably improved following geometric parameter calibration.

Conclusions:

• The TPB phantom method offers a robust and efficient approach for CT geometric calibration.
• This technique effectively addresses geometric misalignments, leading to enhanced image quality.
• The findings support the widespread adoption of this method for improving CT imaging.