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Software breast phantoms have been developed for use in evaluation of novel breast imaging systems. Software
phantoms are flexible allowing the simulation of wide variations in breast anatomy, and provide ground truth for the
simulated tissue structures. Different levels of phantom realism are required depending on the intended application.
Realistic simulation of dense (fibroglandular) tissue is of particular importance; the properties of dense tissue – breast
percent density and the spatial distribution – have been related to the risk of breast cancer. In this work, we have
compared two methods for simulation of dense tissue distribution in a software breast phantom previously developed at
the University of Pennsylvania. The methods compared are: (1) the previously used Gaussian distribution centered at
the phantom nipple point, and (2) the proposed combination of two Beta functions, one modeling the dense tissue
distribution along the chest wall-to-nipple direction, and the other modeling the radial distribution in each coronal
section of the phantom. Dense tissue distributions obtained using these methods have been compared with distributions
reported in the literature estimated from the analysis of breast CT images. Qualitatively, the two methods produced
rather similar dense tissue distributions. The simulation based upon the use of Beta functions provides more control
over the simulated distributions through the selection of the various Beta function parameters. Both methods showed
good agreement to the clinical data, suggesting both provide a high level of realism.
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