Modular breast and tumor perfusion phantoms for 4D dynamic contrast-enhanced dedicated breast CT

Background: Tumor heterogeneity presents significant challenges in breast cancer diagnosis and treatment. Four-dimensional dynamic contrast-enhanced dedicated breast CT (4D DCE-bCT) is a novel imaging technique designed to capture contrast agent kinetics with high spatial and temporal resolution, enabling detailed assessment of tumor perfusion and heterogeneity. Purpose: To develop modular breast tumor phantoms capable of simulating a range of physiologically relevant perfusion patterns and structural heterogeneities for validation of 4D DCE-bCT. Methods: Tumor phantoms (1.5 cm diameter) were 3D-printed using clear resin in several designs: small-channel phantoms (0.8 and 1.0 mm diameter), a leaking vessel model with permeable outer walls, gyroid structures (1.3 and 1.5 mm pores) mimicking microvascularization, and a dual-input/output model to replicate heterogeneous perfusion. The phantoms were integrated into a programmable flow system, enabling iodinated contrast (up to 5 mg I/mL) delivery with custom profiles: full wash-in/wash-out, persistent, plateau, and partial wash-out. 4D DCE-bCT acquisitions with a 65 kV + 0.25 mm Cu filter involved 1 pre-contrast scan (360 pulses over a 10-second revolution at 80 mA) followed by three post-contrast phases (400 pulses over 10 revolutions at 32 mA). Images were reconstructed using 40 projections at 5-second intervals using prior image constrained compressed sensing (PICCS). Time–intensity curves (TICs) were analyzed in volumes of interest in various sections of the tumor phantoms. A gamma variate function was fitted to each TIC, and the corresponding fit parameters and coefficients of determination (R ²) were extracted. Results: Dynamic imaging demonstrated successful capture of expected contrast kinetics. Larger channels (1.0 mm) produced 2.5 times greater enhancement compared to smaller ones (0.8 mm). The R ² values for the 0.8 mm and leaking channel were lower, 0.54 and 0.67 versus 0.85 in the 1 mm channel, due to a higher noise level in the signal. The leaking vessel phantom exhibited delayed wash-out by ∼30 s. Distinct flow patterns were evident in the dual-input/output model. The gamma variate parameters showed the expected trends due to the programmed flow patterns. Conclusion: The developed 3D-printed tumor phantoms effectively simulate key perfusion features and point towards the feasibility of using 4D DCE-bCT to image detailed perfusion patterns.