Experimental study to optimize configurations of PCD Spectral CT

Area of Science:

• Medical Imaging Physics
• Detector Technology
• Computational Imaging

Background:

• Photon counting detector based spectral CT (PCD-SCT) is recognized for its high dose efficiency and diagnostic value.
• Despite its advantages, PCD-SCT has not achieved widespread adoption in clinical diagnosis and security inspection.

Purpose of the Study:

• To evaluate the impact of various parameters on PCD-SCT performance, including energy channel count, k-edge materials, energy thresholding, and basis functions.
• To determine optimal configurations for PCD-SCT through combined parameter settings.

Main Methods:

• A "one-step" synthesis method merging basis material decomposition and image synthesis was employed for PCD-SCT.
• Image quality was assessed using an I-RMSE metric, evaluating both signal difference from ground truth and noise levels.
• Virtual monochromatic images were synthesized and validated through numerical simulations and experimental data.

Main Results:

• Increasing energy channels significantly reduced I-RMSE compared to dual-energy systems, with diminishing returns beyond a certain point.
• High-concentration contrast agents introduced substantial errors (up to 50%) in surrounding matter.
• Energy threshold optimization proved crucial for accurate information recovery, and optimal basis materials varied based on imaging targets.

Conclusions:

• Optimizing the number of energy channels in PCD-SCT can yield significant performance gains.
• The presence of contrast agents necessitates careful consideration due to their potential to increase imaging errors.
• Fine-tuning energy thresholds and selecting appropriate basis materials are essential for enhancing information recovery and reducing noise in PCD-SCT.