A statistically defined anthropomorphic software breast phantom

Abstract

Purpose: Digital anthropomorphic breast phantoms have emerged in the past decade because of recent advances in 3D breast x-ray imaging techniques. Computer phantoms in the literature have incorporated power-law noise to represent glandular tissue and branching structures to represent linear components such as ducts. When power-law noise is added to those phantoms in one piece, the simulated fibroglandular tissue is distributed randomly throughout the breast, resulting in dense tissue placement that may not be observed in a real breast. The authors describe a method for enhancing an existing digital anthropomorphic breast phantom by adding binarized power-law noise to a limited area of the breast. Methods: Phantoms with (0.5 mm) 3 voxel size were generated using software developed by Bakic et al. Between 0% and 40% of adipose compartments in each phantom were replaced with binarized power-law noise (b ¼ 3.0) ranging from 0.1 to 0.6 volumetric glandular fraction. The phantoms were compressed to 7.5 cm thickness, then blurred using a 3 Â 3 boxcar kernel and up-sampled to (0.1 mm) 3 voxel size using trilinear interpolation. Following interpolation, the phantoms were adjusted for volumetric glandular fraction using global thresholding. Monoenergetic phantom projections were created, including quantum noise and simulated detector blur. Texture was quantified in the simulated projections using power-spectrum analysis to estimate the power-law exponent b from 25.6 Â 25.6 mm 2 regions of interest. Results: Phantoms were generated with total volumetric glandular fraction ranging from 3% to 24%. Values for b (averaged per projection view) were found to be between 2.67 and 3.73. Thus, the range of textures of the simulated breasts covers the textures observed in clinical images. Conclusions: Using these new techniques, digital anthropomorphic breast phantoms can be generated with a variety of glandular fractions and patterns. b values for this new phantom are comparable with published values for breast tissue in x-ray projection modalities. The combination of conspicuous linear structures and binarized power-law noise added to a limited area of the phantom qualitatively improves its realism.

Population of 224 realistic human subject-based computational breast phantoms

“…The lack of very fine detail structures in turn can negatively impact the realism of the model. To restore these missing data, the work of Lau et al 52 could be used to add detail to our existing models at the high frequencies absent in the bCT data. Their work was specifically developed to enhance existing anthropomorphic breast models.…”

High-resolution, anthropomorphic, computational breast phantom: fusion of rule-based structures with patient-based anatomy

“…[36] Unlike previous work that added PLN throughout all adipose regions, [18] PLN was added only within a boundary mask region between adipose and glandular tissue in order to connect broken glandular tissue and increase spatial high--frequency detail at the glandular contour.…”

Noise, sampling, and the number of projections in cone-beam CT with a flat-panel detector

“…"Clutter phantoms"-popular in the last decade for simulating the anatomical power spectrum in applications such as breast CBCT (Refs. [38][39][40]-are considerably better suited to such measurement, and a collection of spheres of varying diameter and contrast [providing an approximation to noise of the form 1/f 3 associated with a self-similar object (3D fractal)] was shown to provide a good, statistically motivated phantom for physically probing such sampling effects. 12 Further consideration involves the effect of redundant rays on the noise and NPS as shown in Fig.…”