A cascaded analytical model for photon counting CT simulation(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2025年第12期
- Page:
- 1576-1584
- Research Field:
- 医学影像物理
- Publishing date:
Info
- Title:
- A cascaded analytical model for photon counting CT simulation
- Author(s):
- SHENG Jiabing1; 2; 3; ZENG Dong1; 2; 3; BIAN Zhaoying1; 2; 3; MA Jianhua2; 3; 4
- 1. School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China 2. Guangdong Provincial Key Laboratory of Medical Image Processing, Guangzhou 510515, China 3. Guangzhou Key Laboratory of Medical Imaging and Detection Technology, Guangzhou 510515, China 4. School of Life Science and Technology, Xian Jiaotong University, Xian 710049, China
- Keywords:
- Keywords: photon counting computed tomography charge sharing pulse pileup simulation
- PACS:
- R318；R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2025.12.006
- Abstract:
- Abstract: A cascaded analytical model for photon counting CT simulation is developed and validated, which comprehensively accounts for the charge sharing effect and pulse pileup effect in photon counting detectors. To better model charge sharing process, a charge diffusion model is introduced to the original analytical framework for elaborating the charge transport from generation to collection at the anode. For pulse pileup effect, an existing analytical model is adopted and integrated as a post-processing step for projection data. The improved charge sharing model is verified through Monte Carlo simulation experiments using monoenergetic beams at 60, 90, and 120 keV, and the projection data affected by charge sharing effect are derived based on the generated spatial-energy response matrix. Simulations are performed on a water phantom and a Gammex phantom under a 120 kV scanning protocol to evaluate model performance. Water phantom images are qualitatively assessed at a flux of 120 mA, while Gammex phantom images are quantitatively evaluated at 5, 20, 50, and 100 mA. Results show that the spectral response of the established charge sharing model exhibits a maximum absolute percentage deviation of 11.42% relative to Monte Carlo simulation results. Compared with the linear distortion cased by charge sharing, the nonlinear distortion induced by pulse pileup leads to more significant degradation in image quality, especially at high flux. As flux increases, both the mean absolute deviation and standard deviation of linear attenuation coefficients for 30 and 70 mg/mL iodine in the Gammex phantom show an upward trend, further confirming the negative impact of pulse pileup effect on image quality.
Last Update: 2025-12-29