Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jan;12(1):015501.
doi: 10.1117/1.JMI.12.1.015501. Epub 2024 Dec 31.

Examining the influence of digital phantom models in virtual imaging trials for tomographic breast imaging

Amar Kavuri  1 , Mini Das  1   2
Affiliations

Examining the influence of digital phantom models in virtual imaging trials for tomographic breast imaging

Amar Kavuri et al. J Med Imaging (Bellingham). 2025 Jan.

Abstract

Purpose: Digital phantoms are one of the key components of virtual imaging trials (VITs) that aim to assess and optimize new medical imaging systems and algorithms. However, these phantoms vary in their voxel resolution, appearance, and structural details. We investigate whether and how variations between digital phantoms influence system optimization with digital breast tomosynthesis (DBT) as a chosen modality.

Methods: We selected widely used and open-access digital breast phantoms created with different methods and generated an ensemble of DBT images to test acquisition strategies. Human observer performance was evaluated using localization receiver operating characteristic (LROC) studies for each phantom type. Noise power spectrum and gaze metrics were also employed to compare phantoms and generated images.

Results: Our LROC results show that the arc samplings for peak performance were ∼ 2.5 deg and 6 deg in Bakic and XCAT breast phantoms, respectively, for the 3-mm lesion detection task and indicate that system optimization outcomes from VITs can vary with phantom types and structural frequency components. In addition, a significant correlation ( p < 0.01 ) between gaze metrics and diagnostic performance suggests that gaze analysis can be used to understand and evaluate task difficulty in VITs.

Conclusion: Our results point to the critical need to evaluate realism in digital phantoms and ensure sufficient structural variations at spatial frequencies relevant to the intended task. Standardizing phantom generation and validation tools may help reduce discrepancies among independently conducted VITs for system or algorithmic optimizations.

Keywords: digital breast tomosynthesis; digital phantom; gaze metrics; localization receiver operating characteristic; optimization; structure variability; tomosynthesis; virtual imaging trial; virtual imaging trials; virtual phantom.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Sample slice of 25% VGF Bakic (top left) and XCAT breast (top right) phantoms and the corresponding reconstructed DBT slices with a 3-mm spherical lesion on the bottom.
Fig. 2
Fig. 2
Example gaze pattern with fixations and saccades on DBT slices of 25% dense (top) and 50% dense (bottom) phantoms.
Fig. 3
Fig. 3
Power spectra analysis of DBT slices of both types of backgrounds for a sample acquisition protocol of a 60-deg arc span, 35 projections suggest that lack of small and sharp structures in XCAT breast phantoms resulted in lower spectral density at higher frequencies than that of Bakic phantoms.
Fig. 4
Fig. 4
Sample lesion presents regions of DBT slices of both phantoms acquired with different numbers of projections. The black arrows indicate the lesion position.
Fig. 5
Fig. 5
Human observer performance plotted as LROC curves for a sample acquisition of 35 projections over 60 deg in a 3-mm mass detection study in Bakic phantom (top) and XCAT breast phantom (bottom) backgrounds.
Fig. 6
Fig. 6
Human observer performance plotted as the area under LROC (AUC) against the number of projections in a 3-mm mass detection study in Bakic phantom (top) and XCAT breast phantom (bottom) backgrounds. The results suggest the optimal configurations do not change with the task difficulty but change with the background structure type.
Fig. 7
Fig. 7
Average amount of time spent and the average number of fixations made on images (includes lesion absent and lesion present images) plotted for both phantom types. Observers spent a longer time and made more fixations to make decisions on images with Bakic phantom backgrounds in comparison to those with XCAT breast backgrounds.
Fig. 8
Fig. 8
Average value of first hit time, lesion dwell time, and number of fixations on lesion were plotted against the AUC value of each observer (total of six) for both phantom types and two densities.
See this image and copyright information in PMC

Update of

References

    1. Bakic P., et al. , “Virtual tools for validation of X-ray breast imaging systems,” Med. Phys. 40(6Part23), 390–390 (2013). 10.1118/1.4815218 - DOI
    1. Badano A., et al. , “In silico imaging clinical trials for regulatory evaluation: initial considerations for VICTRE, a demonstration study,” Proc. SPIE 10132, 1013220 (2017). 10.1117/12.2255746 - DOI
    1. Das M., Gifford H. C., “Comparison of model-observer and human-observer performance for breast tomosynthesis: effect of reconstruction and acquisition parameters,” Proc. SPIE 7961, 796118 (2011). 10.1117/12.878826 - DOI
    1. Das M., Liang Z., Gifford H. C., “Examining wide-arc digital breast tomosynthesis: optimization using a visual-search model observer,” Proc. SPIE 9412, 94121S (2015). 10.1117/12.2082986 - DOI
    1. Barufaldi B., et al. , “OpenVCT: a GPU-accelerated virtual clinical trial pipeline for mammography and digital breast tomosynthesis,” Proc. SPIE 10573, 1057358 (2018). 10.1117/12.2294935 - DOI