Fig. 1. Diagram of XFCT with pinhole collimator

Fig. 2. Schematic of multi-pinhole XFCT MC model

Fig. 3. Designs of multi-pinhole collimator and phantom. (a) Perpendicular view of lead plate containing three pinholes; (b) cross-section of lead plate containing one pinhole; (c) phantom 1; (d) phantom 2

Fig. 4. Energy spectrum of X-ray source and spectrum of X-ray fluorescence. (a) Energy spectrum of X-ray source; (b) spectrum of X-ray fluorescence

Fig. 5. Simulation results at different tube voltages. (a) Noise as a function of detection angle at different tube voltages; (b) R_SN as a function of tube voltage at different detection angles

Fig. 6. Simulation results at different mass fractions of GNPs. (a) Noise as a function of detection angle at different mass fractions of GNPs; (b) R_SN as a function of mass fraction of GNPs at different detection angles

Fig. 7. Simulation results at different diameters of ROI. (a) Noise as a function of detection angle at different diameters of ROI; (b) R_SN as a function of diameter of ROI at different detection angles

Fig. 8. R_SN at different detection angles. (a) R_SN as a function of diameter of ROI at different detection angles; (b) R_SN as a function of mass fraction of GNPs at different detection angles

Fig. 9. Reconstructed images. (a) Reconstructed image of phantom 2 at detection angle of 90°; (b) reconstructed image of phantom 2 at detection angle of 120°

Fig. 10. Mean value and R_CN of ROI pixel values in reconstructed images. (a) Mean value of ROI pixel values in reconstructed images; (b) R_CN at detection angles of 90° and 120°