Monte Carlo assessment of coded aperture tool for breast imaging: a Mura-mask case study

The main purpose of this work was to perform a rigorous computational study on scintimammography with a Mura-mask based on Monte Carlo simulation of voxelized breast phantoms. Three main objectives were addressed: (1) verification of Geant4 version 10.4, (2) optimization of the imaging setup, and (3) small tumor detection and localization. We successfully verified the Geant4-based imaging of a commonly used phantom in the field. We used a Mura-mask with a \(41\times 41\) array pattern with adjustable thickness, material, and hole shape (box and cylinder); a low-energy high-resolution collimator with different hole shapes (cylinder and hexagon); and a voxelized breast phantom with different sizes (small, medium, and large) and glandularity percentages (low, medium, and high). We also compared the detector crystal outputs of CdZnTe and NaI(Tl). The simulation was followed by a deconvolution procedure, and the data (images) were statistically emphasized. Statistical metrics indicate that the Mura-mask (W material with 1.5 mm thickness and box holes) combined with a CdZnTe detector leads to the optimum point spread function. Finally, a preliminary study on small-sized tumor detection and localization was conducted with different tumor-to-background ratios (from 2 to 12). Tumors with diameters of 5 and 8 mm could be detected, while those of 2 mm were undetectable. Nevertheless, this study enhances our understanding of the early detection of tumors in the field of scintimammography.