Experimental validation of a rapid Monte Carlo based micro-CT simulator

• Published in: Physics in medicine & biology Vol. 49; no. 18; pp. 4321 - 4333
• Main Authors: Colijn, A P, Zbijewski, W, Sasov, A, Beekman, F J
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 21.09.2004
• Subjects: Algorithms; Animals; Computer Simulation; Equipment Failure Analysis - methods; Miniaturization - instrumentation; Models, Biological; Monte Carlo Method; Phantoms, Imaging; Radiographic Image Enhancement - methods; Radiographic Image Interpretation, Computer-Assisted - methods; Radiography, Abdominal - methods; Rats; Reproducibility of Results; Sensitivity and Specificity; Tomography, Spiral Computed - instrumentation; Tomography, Spiral Computed - methods; Tomography, Spiral Computed - veterinary
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/49/18/009

We describe a newly developed, accelerated Monte Carlo simulator of a small animal micro-CT scanner. Transmission measurements using aluminium slabs are employed to estimate the spectrum of the x-ray source. The simulator incorporating this spectrum is validated with micro-CT scans of physical water phantoms of various diameters, some containing stainless steel and Teflon rods. Good agreement is found between simulated and real data: normalized error of simulated projections, as compared to the real ones, is typically smaller than 0.05. Also the reconstructions obtained from simulated and real data are found to be similar. Thereafter, effects of scatter are studied using a voxelized software phantom representing a rat body. It is shown that the scatter fraction can reach tens of per cents in specific areas of the body and therefore scatter can significantly affect quantitative accuracy in small animal CT imaging.