References
- Li, Fu, Umberto Villa, Seonyeong Park, and Mark A. Anastasio. "3-D stochastic numerical breast phantoms for enabling virtual imaging trials of ultrasound computed tomography." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 69, no. 1 (2021): 135-146. DOI: 10.1109/TUFFC.2021.3112544
- Li, Fu; Villa, Umberto; Park, Seonyeong; Anastasio, Mark, 2021, "2D Acoustic Numerical Breast Phantoms and USCT Measurement Data", https://doi.org/10.7910/DVN/CUFVKE, Harvard Dataverse, V1

Overview
- This dataset includes 1,089 two-dimensional slices extracted from 3D numerical breast phantoms (NBPs) for ultrasound computed tomography (USCT) studies. The anatomical structures of these NBPs were obtained using tools from the Virtual Imaging Clinical Trial for Regulatory Evaluation (VICTRE) project. The methods used to modify and extend the VICTRE NBPs for use in USCT studies are described in the publication cited above.
- The NBPs in this dataset represent the following four ACR BI-RADS breast composition categories:
> Type A - The breast is almost entirely fatty
> Type B - There are scattered areas of fibroglandular density in the breast
> Type C - The breast is heterogeneously dense
> Type D - The breast is extremely dense
- Each 2D slice is taken from a different 3D NBP, ensuring that no more than one slice comes from any single phantom.

File Name Format
- Each data file is stored as an HDF5 .mat file. The filenames follow this format: {type}{subject_id}.mat where{type} indicates the breast type (A, B, C, or D), and {subject_id} is a unique identifier assigned to each sample. For example, in the filename D510022534.mat, "D" represents the breast type, and "510022534" is the sample ID.

File Contents
- Each file contains the following variables:
> "type": Breast type
> "sos": Speed-of-sound map [mm/μs]
> "den": Ambient density map [kg/mm³]
> "att": Acoustic attenuation (power-law prefactor) map [dB/ MHzʸ mm]
> "y": power-law exponent
> "label": Tissue label map. Tissue types are denoted using the following labels: water (0), fat (1), skin (2), glandular tissue (29), ligament (88), lesion (200).

- All spatial maps ("sos", "den", "att", and "label") have the same spatial dimensions of 2560 x 2560 pixels, with a pixel size of 0.1 mm x 0.1 mm.
- "sos", "den", and "att" are float32 arrays, and "label" is an 8-bit unsigned integer array.